--- /dev/null
+What: /sys/block/<disk>/bcache/unregister
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ A write to this file causes the backing device or cache to be
+ unregistered. If a backing device had dirty data in the cache,
+ writeback mode is automatically disabled and all dirty data is
+ flushed before the device is unregistered. Caches unregister
+ all associated backing devices before unregistering themselves.
+
+What: /sys/block/<disk>/bcache/clear_stats
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ Writing to this file resets all the statistics for the device.
+
+What: /sys/block/<disk>/bcache/cache
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a backing device that has cache, a symlink to
+ the bcache/ dir of that cache.
+
+What: /sys/block/<disk>/bcache/cache_hits
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: integer number of full cache hits,
+ counted per bio. A partial cache hit counts as a miss.
+
+What: /sys/block/<disk>/bcache/cache_misses
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: integer number of cache misses.
+
+What: /sys/block/<disk>/bcache/cache_hit_ratio
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: cache hits as a percentage.
+
+What: /sys/block/<disk>/bcache/sequential_cutoff
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: Threshold past which sequential IO will
+ skip the cache. Read and written as bytes in human readable
+ units (i.e. echo 10M > sequntial_cutoff).
+
+What: /sys/block/<disk>/bcache/bypassed
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ Sum of all reads and writes that have bypassed the cache (due
+ to the sequential cutoff). Expressed as bytes in human
+ readable units.
+
+What: /sys/block/<disk>/bcache/writeback
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: When on, writeback caching is enabled and
+ writes will be buffered in the cache. When off, caching is in
+ writethrough mode; reads and writes will be added to the
+ cache but no write buffering will take place.
+
+What: /sys/block/<disk>/bcache/writeback_running
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: when off, dirty data will not be written
+ from the cache to the backing device. The cache will still be
+ used to buffer writes until it is mostly full, at which point
+ writes transparently revert to writethrough mode. Intended only
+ for benchmarking/testing.
+
+What: /sys/block/<disk>/bcache/writeback_delay
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: In writeback mode, when dirty data is
+ written to the cache and the cache held no dirty data for that
+ backing device, writeback from cache to backing device starts
+ after this delay, expressed as an integer number of seconds.
+
+What: /sys/block/<disk>/bcache/writeback_percent
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For backing devices: If nonzero, writeback from cache to
+ backing device only takes place when more than this percentage
+ of the cache is used, allowing more write coalescing to take
+ place and reducing total number of writes sent to the backing
+ device. Integer between 0 and 40.
+
+What: /sys/block/<disk>/bcache/synchronous
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, a boolean that allows synchronous mode to be
+ switched on and off. In synchronous mode all writes are ordered
+ such that the cache can reliably recover from unclean shutdown;
+ if disabled bcache will not generally wait for writes to
+ complete but if the cache is not shut down cleanly all data
+ will be discarded from the cache. Should not be turned off with
+ writeback caching enabled.
+
+What: /sys/block/<disk>/bcache/discard
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, a boolean allowing discard/TRIM to be turned off
+ or back on if the device supports it.
+
+What: /sys/block/<disk>/bcache/bucket_size
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, bucket size in human readable units, as set at
+ cache creation time; should match the erase block size of the
+ SSD for optimal performance.
+
+What: /sys/block/<disk>/bcache/nbuckets
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, the number of usable buckets.
+
+What: /sys/block/<disk>/bcache/tree_depth
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, height of the btree excluding leaf nodes (i.e. a
+ one node tree will have a depth of 0).
+
+What: /sys/block/<disk>/bcache/btree_cache_size
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ Number of btree buckets/nodes that are currently cached in
+ memory; cache dynamically grows and shrinks in response to
+ memory pressure from the rest of the system.
+
+What: /sys/block/<disk>/bcache/written
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, total amount of data in human readable units
+ written to the cache, excluding all metadata.
+
+What: /sys/block/<disk>/bcache/btree_written
+Date: November 2010
+Contact: Kent Overstreet <kent.overstreet@gmail.com>
+Description:
+ For a cache, sum of all btree writes in human readable units.
--- /dev/null
+Say you've got a big slow raid 6, and an X-25E or three. Wouldn't it be
+nice if you could use them as cache... Hence bcache.
+
+Wiki and git repositories are at:
+ http://bcache.evilpiepirate.org
+ http://evilpiepirate.org/git/linux-bcache.git
+ http://evilpiepirate.org/git/bcache-tools.git
+
+It's designed around the performance characteristics of SSDs - it only allocates
+in erase block sized buckets, and it uses a hybrid btree/log to track cached
+extants (which can be anywhere from a single sector to the bucket size). It's
+designed to avoid random writes at all costs; it fills up an erase block
+sequentially, then issues a discard before reusing it.
+
+Both writethrough and writeback caching are supported. Writeback defaults to
+off, but can be switched on and off arbitrarily at runtime. Bcache goes to
+great lengths to protect your data - it reliably handles unclean shutdown. (It
+doesn't even have a notion of a clean shutdown; bcache simply doesn't return
+writes as completed until they're on stable storage).
+
+Writeback caching can use most of the cache for buffering writes - writing
+dirty data to the backing device is always done sequentially, scanning from the
+start to the end of the index.
+
+Since random IO is what SSDs excel at, there generally won't be much benefit
+to caching large sequential IO. Bcache detects sequential IO and skips it;
+it also keeps a rolling average of the IO sizes per task, and as long as the
+average is above the cutoff it will skip all IO from that task - instead of
+caching the first 512k after every seek. Backups and large file copies should
+thus entirely bypass the cache.
+
+In the event of a data IO error on the flash it will try to recover by reading
+from disk or invalidating cache entries. For unrecoverable errors (meta data
+or dirty data), caching is automatically disabled; if dirty data was present
+in the cache it first disables writeback caching and waits for all dirty data
+to be flushed.
+
+Getting started:
+You'll need make-bcache from the bcache-tools repository. Both the cache device
+and backing device must be formatted before use.
+ make-bcache -B /dev/sdb
+ make-bcache -C /dev/sdc
+
+make-bcache has the ability to format multiple devices at the same time - if
+you format your backing devices and cache device at the same time, you won't
+have to manually attach:
+ make-bcache -B /dev/sda /dev/sdb -C /dev/sdc
+
+To make bcache devices known to the kernel, echo them to /sys/fs/bcache/register:
+
+ echo /dev/sdb > /sys/fs/bcache/register
+ echo /dev/sdc > /sys/fs/bcache/register
+
+To register your bcache devices automatically, you could add something like
+this to an init script:
+
+ echo /dev/sd* > /sys/fs/bcache/register_quiet
+
+It'll look for bcache superblocks and ignore everything that doesn't have one.
+
+Registering the backing device makes the bcache show up in /dev; you can now
+format it and use it as normal. But the first time using a new bcache device,
+it'll be running in passthrough mode until you attach it to a cache. See the
+section on attaching.
+
+The devices show up at /dev/bcacheN, and can be controlled via sysfs from
+/sys/block/bcacheN/bcache:
+
+ mkfs.ext4 /dev/bcache0
+ mount /dev/bcache0 /mnt
+
+Cache devices are managed as sets; multiple caches per set isn't supported yet
+but will allow for mirroring of metadata and dirty data in the future. Your new
+cache set shows up as /sys/fs/bcache/<UUID>
+
+ATTACHING:
+
+After your cache device and backing device are registered, the backing device
+must be attached to your cache set to enable caching. Attaching a backing
+device to a cache set is done thusly, with the UUID of the cache set in
+/sys/fs/bcache:
+
+ echo <UUID> > /sys/block/bcache0/bcache/attach
+
+This only has to be done once. The next time you reboot, just reregister all
+your bcache devices. If a backing device has data in a cache somewhere, the
+/dev/bcache# device won't be created until the cache shows up - particularly
+important if you have writeback caching turned on.
+
+If you're booting up and your cache device is gone and never coming back, you
+can force run the backing device:
+
+ echo 1 > /sys/block/sdb/bcache/running
+
+(You need to use /sys/block/sdb (or whatever your backing device is called), not
+/sys/block/bcache0, because bcache0 doesn't exist yet. If you're using a
+partition, the bcache directory would be at /sys/block/sdb/sdb2/bcache)
+
+The backing device will still use that cache set if it shows up in the future,
+but all the cached data will be invalidated. If there was dirty data in the
+cache, don't expect the filesystem to be recoverable - you will have massive
+filesystem corruption, though ext4's fsck does work miracles.
+
+SYSFS - BACKING DEVICE:
+
+attach
+ Echo the UUID of a cache set to this file to enable caching.
+
+cache_mode
+ Can be one of either writethrough, writeback, writearound or none.
+
+clear_stats
+ Writing to this file resets the running total stats (not the day/hour/5 minute
+ decaying versions).
+
+detach
+ Write to this file to detach from a cache set. If there is dirty data in the
+ cache, it will be flushed first.
+
+dirty_data
+ Amount of dirty data for this backing device in the cache. Continuously
+ updated unlike the cache set's version, but may be slightly off.
+
+label
+ Name of underlying device.
+
+readahead
+ Size of readahead that should be performed. Defaults to 0. If set to e.g.
+ 1M, it will round cache miss reads up to that size, but without overlapping
+ existing cache entries.
+
+running
+ 1 if bcache is running (i.e. whether the /dev/bcache device exists, whether
+ it's in passthrough mode or caching).
+
+sequential_cutoff
+ A sequential IO will bypass the cache once it passes this threshhold; the
+ most recent 128 IOs are tracked so sequential IO can be detected even when
+ it isn't all done at once.
+
+sequential_merge
+ If non zero, bcache keeps a list of the last 128 requests submitted to compare
+ against all new requests to determine which new requests are sequential
+ continuations of previous requests for the purpose of determining sequential
+ cutoff. This is necessary if the sequential cutoff value is greater than the
+ maximum acceptable sequential size for any single request.
+
+state
+ The backing device can be in one of four different states:
+
+ no cache: Has never been attached to a cache set.
+
+ clean: Part of a cache set, and there is no cached dirty data.
+
+ dirty: Part of a cache set, and there is cached dirty data.
+
+ inconsistent: The backing device was forcibly run by the user when there was
+ dirty data cached but the cache set was unavailable; whatever data was on the
+ backing device has likely been corrupted.
+
+stop
+ Write to this file to shut down the bcache device and close the backing
+ device.
+
+writeback_delay
+ When dirty data is written to the cache and it previously did not contain
+ any, waits some number of seconds before initiating writeback. Defaults to
+ 30.
+
+writeback_percent
+ If nonzero, bcache tries to keep around this percentage of the cache dirty by
+ throttling background writeback and using a PD controller to smoothly adjust
+ the rate.
+
+writeback_rate
+ Rate in sectors per second - if writeback_percent is nonzero, background
+ writeback is throttled to this rate. Continuously adjusted by bcache but may
+ also be set by the user.
+
+writeback_running
+ If off, writeback of dirty data will not take place at all. Dirty data will
+ still be added to the cache until it is mostly full; only meant for
+ benchmarking. Defaults to on.
+
+SYSFS - BACKING DEVICE STATS:
+
+There are directories with these numbers for a running total, as well as
+versions that decay over the past day, hour and 5 minutes; they're also
+aggregated in the cache set directory as well.
+
+bypassed
+ Amount of IO (both reads and writes) that has bypassed the cache
+
+cache_hits
+cache_misses
+cache_hit_ratio
+ Hits and misses are counted per individual IO as bcache sees them; a
+ partial hit is counted as a miss.
+
+cache_bypass_hits
+cache_bypass_misses
+ Hits and misses for IO that is intended to skip the cache are still counted,
+ but broken out here.
+
+cache_miss_collisions
+ Counts instances where data was going to be inserted into the cache from a
+ cache miss, but raced with a write and data was already present (usually 0
+ since the synchronization for cache misses was rewritten)
+
+cache_readaheads
+ Count of times readahead occured.
+
+SYSFS - CACHE SET:
+
+average_key_size
+ Average data per key in the btree.
+
+bdev<0..n>
+ Symlink to each of the attached backing devices.
+
+block_size
+ Block size of the cache devices.
+
+btree_cache_size
+ Amount of memory currently used by the btree cache
+
+bucket_size
+ Size of buckets
+
+cache<0..n>
+ Symlink to each of the cache devices comprising this cache set.
+
+cache_available_percent
+ Percentage of cache device free.
+
+clear_stats
+ Clears the statistics associated with this cache
+
+dirty_data
+ Amount of dirty data is in the cache (updated when garbage collection runs).
+
+flash_vol_create
+ Echoing a size to this file (in human readable units, k/M/G) creates a thinly
+ provisioned volume backed by the cache set.
+
+io_error_halflife
+io_error_limit
+ These determines how many errors we accept before disabling the cache.
+ Each error is decayed by the half life (in # ios). If the decaying count
+ reaches io_error_limit dirty data is written out and the cache is disabled.
+
+journal_delay_ms
+ Journal writes will delay for up to this many milliseconds, unless a cache
+ flush happens sooner. Defaults to 100.
+
+root_usage_percent
+ Percentage of the root btree node in use. If this gets too high the node
+ will split, increasing the tree depth.
+
+stop
+ Write to this file to shut down the cache set - waits until all attached
+ backing devices have been shut down.
+
+tree_depth
+ Depth of the btree (A single node btree has depth 0).
+
+unregister
+ Detaches all backing devices and closes the cache devices; if dirty data is
+ present it will disable writeback caching and wait for it to be flushed.
+
+SYSFS - CACHE SET INTERNAL:
+
+This directory also exposes timings for a number of internal operations, with
+separate files for average duration, average frequency, last occurence and max
+duration: garbage collection, btree read, btree node sorts and btree splits.
+
+active_journal_entries
+ Number of journal entries that are newer than the index.
+
+btree_nodes
+ Total nodes in the btree.
+
+btree_used_percent
+ Average fraction of btree in use.
+
+bset_tree_stats
+ Statistics about the auxiliary search trees
+
+btree_cache_max_chain
+ Longest chain in the btree node cache's hash table
+
+cache_read_races
+ Counts instances where while data was being read from the cache, the bucket
+ was reused and invalidated - i.e. where the pointer was stale after the read
+ completed. When this occurs the data is reread from the backing device.
+
+trigger_gc
+ Writing to this file forces garbage collection to run.
+
+SYSFS - CACHE DEVICE:
+
+block_size
+ Minimum granularity of writes - should match hardware sector size.
+
+btree_written
+ Sum of all btree writes, in (kilo/mega/giga) bytes
+
+bucket_size
+ Size of buckets
+
+cache_replacement_policy
+ One of either lru, fifo or random.
+
+discard
+ Boolean; if on a discard/TRIM will be issued to each bucket before it is
+ reused. Defaults to off, since SATA TRIM is an unqueued command (and thus
+ slow).
+
+freelist_percent
+ Size of the freelist as a percentage of nbuckets. Can be written to to
+ increase the number of buckets kept on the freelist, which lets you
+ artificially reduce the size of the cache at runtime. Mostly for testing
+ purposes (i.e. testing how different size caches affect your hit rate), but
+ since buckets are discarded when they move on to the freelist will also make
+ the SSD's garbage collection easier by effectively giving it more reserved
+ space.
+
+io_errors
+ Number of errors that have occured, decayed by io_error_halflife.
+
+metadata_written
+ Sum of all non data writes (btree writes and all other metadata).
+
+nbuckets
+ Total buckets in this cache
+
+priority_stats
+ Statistics about how recently data in the cache has been accessed. This can
+ reveal your working set size.
+
+written
+ Sum of all data that has been written to the cache; comparison with
+ btree_written gives the amount of write inflation in bcache.
S: Maintained
F: drivers/net/hamradio/baycom*
+BCACHE (BLOCK LAYER CACHE)
+M: Kent Overstreet <koverstreet@google.com>
+L: linux-bcache@vger.kernel.org
+W: http://bcache.evilpiepirate.org
+S: Maintained:
+F: drivers/md/bcache/
+
BEFS FILE SYSTEM
S: Orphan
F: Documentation/filesystems/befs.txt
In unsure, say N.
+source "drivers/md/bcache/Kconfig"
+
config BLK_DEV_DM
tristate "Device mapper support"
---help---
obj-$(CONFIG_MD_RAID456) += raid456.o
obj-$(CONFIG_MD_MULTIPATH) += multipath.o
obj-$(CONFIG_MD_FAULTY) += faulty.o
+obj-$(CONFIG_BCACHE) += bcache/
obj-$(CONFIG_BLK_DEV_MD) += md-mod.o
obj-$(CONFIG_BLK_DEV_DM) += dm-mod.o
obj-$(CONFIG_DM_BUFIO) += dm-bufio.o
--- /dev/null
+
+config BCACHE
+ tristate "Block device as cache"
+ select CLOSURES
+ ---help---
+ Allows a block device to be used as cache for other devices; uses
+ a btree for indexing and the layout is optimized for SSDs.
+
+ See Documentation/bcache.txt for details.
+
+config BCACHE_DEBUG
+ bool "Bcache debugging"
+ depends on BCACHE
+ ---help---
+ Don't select this option unless you're a developer
+
+ Enables extra debugging tools (primarily a fuzz tester)
+
+config BCACHE_EDEBUG
+ bool "Extended runtime checks"
+ depends on BCACHE
+ ---help---
+ Don't select this option unless you're a developer
+
+ Enables extra runtime checks which significantly affect performance
+
+config BCACHE_CLOSURES_DEBUG
+ bool "Debug closures"
+ depends on BCACHE
+ select DEBUG_FS
+ ---help---
+ Keeps all active closures in a linked list and provides a debugfs
+ interface to list them, which makes it possible to see asynchronous
+ operations that get stuck.
+
+# cgroup code needs to be updated:
+#
+#config CGROUP_BCACHE
+# bool "Cgroup controls for bcache"
+# depends on BCACHE && BLK_CGROUP
+# ---help---
+# TODO
--- /dev/null
+
+obj-$(CONFIG_BCACHE) += bcache.o
+
+bcache-y := alloc.o btree.o bset.o io.o journal.o writeback.o\
+ movinggc.o request.o super.o sysfs.o debug.o util.o trace.o stats.o closure.o
+
+CFLAGS_request.o += -Iblock
--- /dev/null
+/*
+ * Primary bucket allocation code
+ *
+ * Copyright 2012 Google, Inc.
+ *
+ * Allocation in bcache is done in terms of buckets:
+ *
+ * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in
+ * btree pointers - they must match for the pointer to be considered valid.
+ *
+ * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a
+ * bucket simply by incrementing its gen.
+ *
+ * The gens (along with the priorities; it's really the gens are important but
+ * the code is named as if it's the priorities) are written in an arbitrary list
+ * of buckets on disk, with a pointer to them in the journal header.
+ *
+ * When we invalidate a bucket, we have to write its new gen to disk and wait
+ * for that write to complete before we use it - otherwise after a crash we
+ * could have pointers that appeared to be good but pointed to data that had
+ * been overwritten.
+ *
+ * Since the gens and priorities are all stored contiguously on disk, we can
+ * batch this up: We fill up the free_inc list with freshly invalidated buckets,
+ * call prio_write(), and when prio_write() finishes we pull buckets off the
+ * free_inc list and optionally discard them.
+ *
+ * free_inc isn't the only freelist - if it was, we'd often to sleep while
+ * priorities and gens were being written before we could allocate. c->free is a
+ * smaller freelist, and buckets on that list are always ready to be used.
+ *
+ * If we've got discards enabled, that happens when a bucket moves from the
+ * free_inc list to the free list.
+ *
+ * There is another freelist, because sometimes we have buckets that we know
+ * have nothing pointing into them - these we can reuse without waiting for
+ * priorities to be rewritten. These come from freed btree nodes and buckets
+ * that garbage collection discovered no longer had valid keys pointing into
+ * them (because they were overwritten). That's the unused list - buckets on the
+ * unused list move to the free list, optionally being discarded in the process.
+ *
+ * It's also important to ensure that gens don't wrap around - with respect to
+ * either the oldest gen in the btree or the gen on disk. This is quite
+ * difficult to do in practice, but we explicitly guard against it anyways - if
+ * a bucket is in danger of wrapping around we simply skip invalidating it that
+ * time around, and we garbage collect or rewrite the priorities sooner than we
+ * would have otherwise.
+ *
+ * bch_bucket_alloc() allocates a single bucket from a specific cache.
+ *
+ * bch_bucket_alloc_set() allocates one or more buckets from different caches
+ * out of a cache set.
+ *
+ * free_some_buckets() drives all the processes described above. It's called
+ * from bch_bucket_alloc() and a few other places that need to make sure free
+ * buckets are ready.
+ *
+ * invalidate_buckets_(lru|fifo)() find buckets that are available to be
+ * invalidated, and then invalidate them and stick them on the free_inc list -
+ * in either lru or fifo order.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+
+#include <linux/random.h>
+
+#define MAX_IN_FLIGHT_DISCARDS 8U
+
+/* Bucket heap / gen */
+
+uint8_t bch_inc_gen(struct cache *ca, struct bucket *b)
+{
+ uint8_t ret = ++b->gen;
+
+ ca->set->need_gc = max(ca->set->need_gc, bucket_gc_gen(b));
+ WARN_ON_ONCE(ca->set->need_gc > BUCKET_GC_GEN_MAX);
+
+ if (CACHE_SYNC(&ca->set->sb)) {
+ ca->need_save_prio = max(ca->need_save_prio,
+ bucket_disk_gen(b));
+ WARN_ON_ONCE(ca->need_save_prio > BUCKET_DISK_GEN_MAX);
+ }
+
+ return ret;
+}
+
+void bch_rescale_priorities(struct cache_set *c, int sectors)
+{
+ struct cache *ca;
+ struct bucket *b;
+ unsigned next = c->nbuckets * c->sb.bucket_size / 1024;
+ unsigned i;
+ int r;
+
+ atomic_sub(sectors, &c->rescale);
+
+ do {
+ r = atomic_read(&c->rescale);
+
+ if (r >= 0)
+ return;
+ } while (atomic_cmpxchg(&c->rescale, r, r + next) != r);
+
+ mutex_lock(&c->bucket_lock);
+
+ c->min_prio = USHRT_MAX;
+
+ for_each_cache(ca, c, i)
+ for_each_bucket(b, ca)
+ if (b->prio &&
+ b->prio != BTREE_PRIO &&
+ !atomic_read(&b->pin)) {
+ b->prio--;
+ c->min_prio = min(c->min_prio, b->prio);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+/* Discard/TRIM */
+
+struct discard {
+ struct list_head list;
+ struct work_struct work;
+ struct cache *ca;
+ long bucket;
+
+ struct bio bio;
+ struct bio_vec bv;
+};
+
+static void discard_finish(struct work_struct *w)
+{
+ struct discard *d = container_of(w, struct discard, work);
+ struct cache *ca = d->ca;
+ char buf[BDEVNAME_SIZE];
+
+ if (!test_bit(BIO_UPTODATE, &d->bio.bi_flags)) {
+ pr_notice("discard error on %s, disabling",
+ bdevname(ca->bdev, buf));
+ d->ca->discard = 0;
+ }
+
+ mutex_lock(&ca->set->bucket_lock);
+
+ fifo_push(&ca->free, d->bucket);
+ list_add(&d->list, &ca->discards);
+ atomic_dec(&ca->discards_in_flight);
+
+ mutex_unlock(&ca->set->bucket_lock);
+
+ closure_wake_up(&ca->set->bucket_wait);
+ wake_up(&ca->set->alloc_wait);
+
+ closure_put(&ca->set->cl);
+}
+
+static void discard_endio(struct bio *bio, int error)
+{
+ struct discard *d = container_of(bio, struct discard, bio);
+ schedule_work(&d->work);
+}
+
+static void do_discard(struct cache *ca, long bucket)
+{
+ struct discard *d = list_first_entry(&ca->discards,
+ struct discard, list);
+
+ list_del(&d->list);
+ d->bucket = bucket;
+
+ atomic_inc(&ca->discards_in_flight);
+ closure_get(&ca->set->cl);
+
+ bio_init(&d->bio);
+
+ d->bio.bi_sector = bucket_to_sector(ca->set, d->bucket);
+ d->bio.bi_bdev = ca->bdev;
+ d->bio.bi_rw = REQ_WRITE|REQ_DISCARD;
+ d->bio.bi_max_vecs = 1;
+ d->bio.bi_io_vec = d->bio.bi_inline_vecs;
+ d->bio.bi_size = bucket_bytes(ca);
+ d->bio.bi_end_io = discard_endio;
+ bio_set_prio(&d->bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+
+ submit_bio(0, &d->bio);
+}
+
+/* Allocation */
+
+static inline bool can_inc_bucket_gen(struct bucket *b)
+{
+ return bucket_gc_gen(b) < BUCKET_GC_GEN_MAX &&
+ bucket_disk_gen(b) < BUCKET_DISK_GEN_MAX;
+}
+
+bool bch_bucket_add_unused(struct cache *ca, struct bucket *b)
+{
+ BUG_ON(GC_MARK(b) || GC_SECTORS_USED(b));
+
+ if (fifo_used(&ca->free) > ca->watermark[WATERMARK_MOVINGGC] &&
+ CACHE_REPLACEMENT(&ca->sb) == CACHE_REPLACEMENT_FIFO)
+ return false;
+
+ b->prio = 0;
+
+ if (can_inc_bucket_gen(b) &&
+ fifo_push(&ca->unused, b - ca->buckets)) {
+ atomic_inc(&b->pin);
+ return true;
+ }
+
+ return false;
+}
+
+static bool can_invalidate_bucket(struct cache *ca, struct bucket *b)
+{
+ return GC_MARK(b) == GC_MARK_RECLAIMABLE &&
+ !atomic_read(&b->pin) &&
+ can_inc_bucket_gen(b);
+}
+
+static void invalidate_one_bucket(struct cache *ca, struct bucket *b)
+{
+ bch_inc_gen(ca, b);
+ b->prio = INITIAL_PRIO;
+ atomic_inc(&b->pin);
+ fifo_push(&ca->free_inc, b - ca->buckets);
+}
+
+static void invalidate_buckets_lru(struct cache *ca)
+{
+ unsigned bucket_prio(struct bucket *b)
+ {
+ return ((unsigned) (b->prio - ca->set->min_prio)) *
+ GC_SECTORS_USED(b);
+ }
+
+ bool bucket_max_cmp(struct bucket *l, struct bucket *r)
+ {
+ return bucket_prio(l) < bucket_prio(r);
+ }
+
+ bool bucket_min_cmp(struct bucket *l, struct bucket *r)
+ {
+ return bucket_prio(l) > bucket_prio(r);
+ }
+
+ struct bucket *b;
+ ssize_t i;
+
+ ca->heap.used = 0;
+
+ for_each_bucket(b, ca) {
+ if (!can_invalidate_bucket(ca, b))
+ continue;
+
+ if (!GC_SECTORS_USED(b)) {
+ if (!bch_bucket_add_unused(ca, b))
+ return;
+ } else {
+ if (!heap_full(&ca->heap))
+ heap_add(&ca->heap, b, bucket_max_cmp);
+ else if (bucket_max_cmp(b, heap_peek(&ca->heap))) {
+ ca->heap.data[0] = b;
+ heap_sift(&ca->heap, 0, bucket_max_cmp);
+ }
+ }
+ }
+
+ if (ca->heap.used * 2 < ca->heap.size)
+ bch_queue_gc(ca->set);
+
+ for (i = ca->heap.used / 2 - 1; i >= 0; --i)
+ heap_sift(&ca->heap, i, bucket_min_cmp);
+
+ while (!fifo_full(&ca->free_inc)) {
+ if (!heap_pop(&ca->heap, b, bucket_min_cmp)) {
+ /* We don't want to be calling invalidate_buckets()
+ * multiple times when it can't do anything
+ */
+ ca->invalidate_needs_gc = 1;
+ bch_queue_gc(ca->set);
+ return;
+ }
+
+ invalidate_one_bucket(ca, b);
+ }
+}
+
+static void invalidate_buckets_fifo(struct cache *ca)
+{
+ struct bucket *b;
+ size_t checked = 0;
+
+ while (!fifo_full(&ca->free_inc)) {
+ if (ca->fifo_last_bucket < ca->sb.first_bucket ||
+ ca->fifo_last_bucket >= ca->sb.nbuckets)
+ ca->fifo_last_bucket = ca->sb.first_bucket;
+
+ b = ca->buckets + ca->fifo_last_bucket++;
+
+ if (can_invalidate_bucket(ca, b))
+ invalidate_one_bucket(ca, b);
+
+ if (++checked >= ca->sb.nbuckets) {
+ ca->invalidate_needs_gc = 1;
+ bch_queue_gc(ca->set);
+ return;
+ }
+ }
+}
+
+static void invalidate_buckets_random(struct cache *ca)
+{
+ struct bucket *b;
+ size_t checked = 0;
+
+ while (!fifo_full(&ca->free_inc)) {
+ size_t n;
+ get_random_bytes(&n, sizeof(n));
+
+ n %= (size_t) (ca->sb.nbuckets - ca->sb.first_bucket);
+ n += ca->sb.first_bucket;
+
+ b = ca->buckets + n;
+
+ if (can_invalidate_bucket(ca, b))
+ invalidate_one_bucket(ca, b);
+
+ if (++checked >= ca->sb.nbuckets / 2) {
+ ca->invalidate_needs_gc = 1;
+ bch_queue_gc(ca->set);
+ return;
+ }
+ }
+}
+
+static void invalidate_buckets(struct cache *ca)
+{
+ if (ca->invalidate_needs_gc)
+ return;
+
+ switch (CACHE_REPLACEMENT(&ca->sb)) {
+ case CACHE_REPLACEMENT_LRU:
+ invalidate_buckets_lru(ca);
+ break;
+ case CACHE_REPLACEMENT_FIFO:
+ invalidate_buckets_fifo(ca);
+ break;
+ case CACHE_REPLACEMENT_RANDOM:
+ invalidate_buckets_random(ca);
+ break;
+ }
+}
+
+#define allocator_wait(ca, cond) \
+do { \
+ DEFINE_WAIT(__wait); \
+ \
+ while (!(cond)) { \
+ prepare_to_wait(&ca->set->alloc_wait, \
+ &__wait, TASK_INTERRUPTIBLE); \
+ \
+ mutex_unlock(&(ca)->set->bucket_lock); \
+ if (test_bit(CACHE_SET_STOPPING_2, &ca->set->flags)) { \
+ finish_wait(&ca->set->alloc_wait, &__wait); \
+ closure_return(cl); \
+ } \
+ \
+ schedule(); \
+ __set_current_state(TASK_RUNNING); \
+ mutex_lock(&(ca)->set->bucket_lock); \
+ } \
+ \
+ finish_wait(&ca->set->alloc_wait, &__wait); \
+} while (0)
+
+void bch_allocator_thread(struct closure *cl)
+{
+ struct cache *ca = container_of(cl, struct cache, alloc);
+
+ mutex_lock(&ca->set->bucket_lock);
+
+ while (1) {
+ while (1) {
+ long bucket;
+
+ if ((!atomic_read(&ca->set->prio_blocked) ||
+ !CACHE_SYNC(&ca->set->sb)) &&
+ !fifo_empty(&ca->unused))
+ fifo_pop(&ca->unused, bucket);
+ else if (!fifo_empty(&ca->free_inc))
+ fifo_pop(&ca->free_inc, bucket);
+ else
+ break;
+
+ allocator_wait(ca, (int) fifo_free(&ca->free) >
+ atomic_read(&ca->discards_in_flight));
+
+ if (ca->discard) {
+ allocator_wait(ca, !list_empty(&ca->discards));
+ do_discard(ca, bucket);
+ } else {
+ fifo_push(&ca->free, bucket);
+ closure_wake_up(&ca->set->bucket_wait);
+ }
+ }
+
+ allocator_wait(ca, ca->set->gc_mark_valid);
+ invalidate_buckets(ca);
+
+ allocator_wait(ca, !atomic_read(&ca->set->prio_blocked) ||
+ !CACHE_SYNC(&ca->set->sb));
+
+ if (CACHE_SYNC(&ca->set->sb) &&
+ (!fifo_empty(&ca->free_inc) ||
+ ca->need_save_prio > 64)) {
+ bch_prio_write(ca);
+ }
+ }
+}
+
+long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl)
+{
+ long r = -1;
+again:
+ wake_up(&ca->set->alloc_wait);
+
+ if (fifo_used(&ca->free) > ca->watermark[watermark] &&
+ fifo_pop(&ca->free, r)) {
+ struct bucket *b = ca->buckets + r;
+#ifdef CONFIG_BCACHE_EDEBUG
+ size_t iter;
+ long i;
+
+ for (iter = 0; iter < prio_buckets(ca) * 2; iter++)
+ BUG_ON(ca->prio_buckets[iter] == (uint64_t) r);
+
+ fifo_for_each(i, &ca->free, iter)
+ BUG_ON(i == r);
+ fifo_for_each(i, &ca->free_inc, iter)
+ BUG_ON(i == r);
+ fifo_for_each(i, &ca->unused, iter)
+ BUG_ON(i == r);
+#endif
+ BUG_ON(atomic_read(&b->pin) != 1);
+
+ SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
+
+ if (watermark <= WATERMARK_METADATA) {
+ SET_GC_MARK(b, GC_MARK_METADATA);
+ b->prio = BTREE_PRIO;
+ } else {
+ SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
+ b->prio = INITIAL_PRIO;
+ }
+
+ return r;
+ }
+
+ pr_debug("alloc failure: blocked %i free %zu free_inc %zu unused %zu",
+ atomic_read(&ca->set->prio_blocked), fifo_used(&ca->free),
+ fifo_used(&ca->free_inc), fifo_used(&ca->unused));
+
+ if (cl) {
+ closure_wait(&ca->set->bucket_wait, cl);
+
+ if (closure_blocking(cl)) {
+ mutex_unlock(&ca->set->bucket_lock);
+ closure_sync(cl);
+ mutex_lock(&ca->set->bucket_lock);
+ goto again;
+ }
+ }
+
+ return -1;
+}
+
+void bch_bucket_free(struct cache_set *c, struct bkey *k)
+{
+ unsigned i;
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ struct bucket *b = PTR_BUCKET(c, k, i);
+
+ SET_GC_MARK(b, 0);
+ SET_GC_SECTORS_USED(b, 0);
+ bch_bucket_add_unused(PTR_CACHE(c, k, i), b);
+ }
+}
+
+int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
+ struct bkey *k, int n, struct closure *cl)
+{
+ int i;
+
+ lockdep_assert_held(&c->bucket_lock);
+ BUG_ON(!n || n > c->caches_loaded || n > 8);
+
+ bkey_init(k);
+
+ /* sort by free space/prio of oldest data in caches */
+
+ for (i = 0; i < n; i++) {
+ struct cache *ca = c->cache_by_alloc[i];
+ long b = bch_bucket_alloc(ca, watermark, cl);
+
+ if (b == -1)
+ goto err;
+
+ k->ptr[i] = PTR(ca->buckets[b].gen,
+ bucket_to_sector(c, b),
+ ca->sb.nr_this_dev);
+
+ SET_KEY_PTRS(k, i + 1);
+ }
+
+ return 0;
+err:
+ bch_bucket_free(c, k);
+ __bkey_put(c, k);
+ return -1;
+}
+
+int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
+ struct bkey *k, int n, struct closure *cl)
+{
+ int ret;
+ mutex_lock(&c->bucket_lock);
+ ret = __bch_bucket_alloc_set(c, watermark, k, n, cl);
+ mutex_unlock(&c->bucket_lock);
+ return ret;
+}
+
+/* Init */
+
+void bch_cache_allocator_exit(struct cache *ca)
+{
+ struct discard *d;
+
+ while (!list_empty(&ca->discards)) {
+ d = list_first_entry(&ca->discards, struct discard, list);
+ cancel_work_sync(&d->work);
+ list_del(&d->list);
+ kfree(d);
+ }
+}
+
+int bch_cache_allocator_init(struct cache *ca)
+{
+ unsigned i;
+
+ /*
+ * Reserve:
+ * Prio/gen writes first
+ * Then 8 for btree allocations
+ * Then half for the moving garbage collector
+ */
+
+ ca->watermark[WATERMARK_PRIO] = 0;
+
+ ca->watermark[WATERMARK_METADATA] = prio_buckets(ca);
+
+ ca->watermark[WATERMARK_MOVINGGC] = 8 +
+ ca->watermark[WATERMARK_METADATA];
+
+ ca->watermark[WATERMARK_NONE] = ca->free.size / 2 +
+ ca->watermark[WATERMARK_MOVINGGC];
+
+ for (i = 0; i < MAX_IN_FLIGHT_DISCARDS; i++) {
+ struct discard *d = kzalloc(sizeof(*d), GFP_KERNEL);
+ if (!d)
+ return -ENOMEM;
+
+ d->ca = ca;
+ INIT_WORK(&d->work, discard_finish);
+ list_add(&d->list, &ca->discards);
+ }
+
+ return 0;
+}
--- /dev/null
+#ifndef _BCACHE_H
+#define _BCACHE_H
+
+/*
+ * SOME HIGH LEVEL CODE DOCUMENTATION:
+ *
+ * Bcache mostly works with cache sets, cache devices, and backing devices.
+ *
+ * Support for multiple cache devices hasn't quite been finished off yet, but
+ * it's about 95% plumbed through. A cache set and its cache devices is sort of
+ * like a md raid array and its component devices. Most of the code doesn't care
+ * about individual cache devices, the main abstraction is the cache set.
+ *
+ * Multiple cache devices is intended to give us the ability to mirror dirty
+ * cached data and metadata, without mirroring clean cached data.
+ *
+ * Backing devices are different, in that they have a lifetime independent of a
+ * cache set. When you register a newly formatted backing device it'll come up
+ * in passthrough mode, and then you can attach and detach a backing device from
+ * a cache set at runtime - while it's mounted and in use. Detaching implicitly
+ * invalidates any cached data for that backing device.
+ *
+ * A cache set can have multiple (many) backing devices attached to it.
+ *
+ * There's also flash only volumes - this is the reason for the distinction
+ * between struct cached_dev and struct bcache_device. A flash only volume
+ * works much like a bcache device that has a backing device, except the
+ * "cached" data is always dirty. The end result is that we get thin
+ * provisioning with very little additional code.
+ *
+ * Flash only volumes work but they're not production ready because the moving
+ * garbage collector needs more work. More on that later.
+ *
+ * BUCKETS/ALLOCATION:
+ *
+ * Bcache is primarily designed for caching, which means that in normal
+ * operation all of our available space will be allocated. Thus, we need an
+ * efficient way of deleting things from the cache so we can write new things to
+ * it.
+ *
+ * To do this, we first divide the cache device up into buckets. A bucket is the
+ * unit of allocation; they're typically around 1 mb - anywhere from 128k to 2M+
+ * works efficiently.
+ *
+ * Each bucket has a 16 bit priority, and an 8 bit generation associated with
+ * it. The gens and priorities for all the buckets are stored contiguously and
+ * packed on disk (in a linked list of buckets - aside from the superblock, all
+ * of bcache's metadata is stored in buckets).
+ *
+ * The priority is used to implement an LRU. We reset a bucket's priority when
+ * we allocate it or on cache it, and every so often we decrement the priority
+ * of each bucket. It could be used to implement something more sophisticated,
+ * if anyone ever gets around to it.
+ *
+ * The generation is used for invalidating buckets. Each pointer also has an 8
+ * bit generation embedded in it; for a pointer to be considered valid, its gen
+ * must match the gen of the bucket it points into. Thus, to reuse a bucket all
+ * we have to do is increment its gen (and write its new gen to disk; we batch
+ * this up).
+ *
+ * Bcache is entirely COW - we never write twice to a bucket, even buckets that
+ * contain metadata (including btree nodes).
+ *
+ * THE BTREE:
+ *
+ * Bcache is in large part design around the btree.
+ *
+ * At a high level, the btree is just an index of key -> ptr tuples.
+ *
+ * Keys represent extents, and thus have a size field. Keys also have a variable
+ * number of pointers attached to them (potentially zero, which is handy for
+ * invalidating the cache).
+ *
+ * The key itself is an inode:offset pair. The inode number corresponds to a
+ * backing device or a flash only volume. The offset is the ending offset of the
+ * extent within the inode - not the starting offset; this makes lookups
+ * slightly more convenient.
+ *
+ * Pointers contain the cache device id, the offset on that device, and an 8 bit
+ * generation number. More on the gen later.
+ *
+ * Index lookups are not fully abstracted - cache lookups in particular are
+ * still somewhat mixed in with the btree code, but things are headed in that
+ * direction.
+ *
+ * Updates are fairly well abstracted, though. There are two different ways of
+ * updating the btree; insert and replace.
+ *
+ * BTREE_INSERT will just take a list of keys and insert them into the btree -
+ * overwriting (possibly only partially) any extents they overlap with. This is
+ * used to update the index after a write.
+ *
+ * BTREE_REPLACE is really cmpxchg(); it inserts a key into the btree iff it is
+ * overwriting a key that matches another given key. This is used for inserting
+ * data into the cache after a cache miss, and for background writeback, and for
+ * the moving garbage collector.
+ *
+ * There is no "delete" operation; deleting things from the index is
+ * accomplished by either by invalidating pointers (by incrementing a bucket's
+ * gen) or by inserting a key with 0 pointers - which will overwrite anything
+ * previously present at that location in the index.
+ *
+ * This means that there are always stale/invalid keys in the btree. They're
+ * filtered out by the code that iterates through a btree node, and removed when
+ * a btree node is rewritten.
+ *
+ * BTREE NODES:
+ *
+ * Our unit of allocation is a bucket, and we we can't arbitrarily allocate and
+ * free smaller than a bucket - so, that's how big our btree nodes are.
+ *
+ * (If buckets are really big we'll only use part of the bucket for a btree node
+ * - no less than 1/4th - but a bucket still contains no more than a single
+ * btree node. I'd actually like to change this, but for now we rely on the
+ * bucket's gen for deleting btree nodes when we rewrite/split a node.)
+ *
+ * Anyways, btree nodes are big - big enough to be inefficient with a textbook
+ * btree implementation.
+ *
+ * The way this is solved is that btree nodes are internally log structured; we
+ * can append new keys to an existing btree node without rewriting it. This
+ * means each set of keys we write is sorted, but the node is not.
+ *
+ * We maintain this log structure in memory - keeping 1Mb of keys sorted would
+ * be expensive, and we have to distinguish between the keys we have written and
+ * the keys we haven't. So to do a lookup in a btree node, we have to search
+ * each sorted set. But we do merge written sets together lazily, so the cost of
+ * these extra searches is quite low (normally most of the keys in a btree node
+ * will be in one big set, and then there'll be one or two sets that are much
+ * smaller).
+ *
+ * This log structure makes bcache's btree more of a hybrid between a
+ * conventional btree and a compacting data structure, with some of the
+ * advantages of both.
+ *
+ * GARBAGE COLLECTION:
+ *
+ * We can't just invalidate any bucket - it might contain dirty data or
+ * metadata. If it once contained dirty data, other writes might overwrite it
+ * later, leaving no valid pointers into that bucket in the index.
+ *
+ * Thus, the primary purpose of garbage collection is to find buckets to reuse.
+ * It also counts how much valid data it each bucket currently contains, so that
+ * allocation can reuse buckets sooner when they've been mostly overwritten.
+ *
+ * It also does some things that are really internal to the btree
+ * implementation. If a btree node contains pointers that are stale by more than
+ * some threshold, it rewrites the btree node to avoid the bucket's generation
+ * wrapping around. It also merges adjacent btree nodes if they're empty enough.
+ *
+ * THE JOURNAL:
+ *
+ * Bcache's journal is not necessary for consistency; we always strictly
+ * order metadata writes so that the btree and everything else is consistent on
+ * disk in the event of an unclean shutdown, and in fact bcache had writeback
+ * caching (with recovery from unclean shutdown) before journalling was
+ * implemented.
+ *
+ * Rather, the journal is purely a performance optimization; we can't complete a
+ * write until we've updated the index on disk, otherwise the cache would be
+ * inconsistent in the event of an unclean shutdown. This means that without the
+ * journal, on random write workloads we constantly have to update all the leaf
+ * nodes in the btree, and those writes will be mostly empty (appending at most
+ * a few keys each) - highly inefficient in terms of amount of metadata writes,
+ * and it puts more strain on the various btree resorting/compacting code.
+ *
+ * The journal is just a log of keys we've inserted; on startup we just reinsert
+ * all the keys in the open journal entries. That means that when we're updating
+ * a node in the btree, we can wait until a 4k block of keys fills up before
+ * writing them out.
+ *
+ * For simplicity, we only journal updates to leaf nodes; updates to parent
+ * nodes are rare enough (since our leaf nodes are huge) that it wasn't worth
+ * the complexity to deal with journalling them (in particular, journal replay)
+ * - updates to non leaf nodes just happen synchronously (see btree_split()).
+ */
+
+#define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
+
+#include <linux/bio.h>
+#include <linux/blktrace_api.h>
+#include <linux/kobject.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/rbtree.h>
+#include <linux/rwsem.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include "util.h"
+#include "closure.h"
+
+struct bucket {
+ atomic_t pin;
+ uint16_t prio;
+ uint8_t gen;
+ uint8_t disk_gen;
+ uint8_t last_gc; /* Most out of date gen in the btree */
+ uint8_t gc_gen;
+ uint16_t gc_mark;
+};
+
+/*
+ * I'd use bitfields for these, but I don't trust the compiler not to screw me
+ * as multiple threads touch struct bucket without locking
+ */
+
+BITMASK(GC_MARK, struct bucket, gc_mark, 0, 2);
+#define GC_MARK_RECLAIMABLE 0
+#define GC_MARK_DIRTY 1
+#define GC_MARK_METADATA 2
+BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, 14);
+
+struct bkey {
+ uint64_t high;
+ uint64_t low;
+ uint64_t ptr[];
+};
+
+/* Enough for a key with 6 pointers */
+#define BKEY_PAD 8
+
+#define BKEY_PADDED(key) \
+ union { struct bkey key; uint64_t key ## _pad[BKEY_PAD]; }
+
+/* Version 1: Backing device
+ * Version 2: Seed pointer into btree node checksum
+ * Version 3: New UUID format
+ */
+#define BCACHE_SB_VERSION 3
+
+#define SB_SECTOR 8
+#define SB_SIZE 4096
+#define SB_LABEL_SIZE 32
+#define SB_JOURNAL_BUCKETS 256U
+/* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
+#define MAX_CACHES_PER_SET 8
+
+#define BDEV_DATA_START 16 /* sectors */
+
+struct cache_sb {
+ uint64_t csum;
+ uint64_t offset; /* sector where this sb was written */
+ uint64_t version;
+#define CACHE_BACKING_DEV 1
+
+ uint8_t magic[16];
+
+ uint8_t uuid[16];
+ union {
+ uint8_t set_uuid[16];
+ uint64_t set_magic;
+ };
+ uint8_t label[SB_LABEL_SIZE];
+
+ uint64_t flags;
+ uint64_t seq;
+ uint64_t pad[8];
+
+ uint64_t nbuckets; /* device size */
+ uint16_t block_size; /* sectors */
+ uint16_t bucket_size; /* sectors */
+
+ uint16_t nr_in_set;
+ uint16_t nr_this_dev;
+
+ uint32_t last_mount; /* time_t */
+
+ uint16_t first_bucket;
+ union {
+ uint16_t njournal_buckets;
+ uint16_t keys;
+ };
+ uint64_t d[SB_JOURNAL_BUCKETS]; /* journal buckets */
+};
+
+BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1);
+BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1);
+BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3);
+#define CACHE_REPLACEMENT_LRU 0U
+#define CACHE_REPLACEMENT_FIFO 1U
+#define CACHE_REPLACEMENT_RANDOM 2U
+
+BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4);
+#define CACHE_MODE_WRITETHROUGH 0U
+#define CACHE_MODE_WRITEBACK 1U
+#define CACHE_MODE_WRITEAROUND 2U
+#define CACHE_MODE_NONE 3U
+BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2);
+#define BDEV_STATE_NONE 0U
+#define BDEV_STATE_CLEAN 1U
+#define BDEV_STATE_DIRTY 2U
+#define BDEV_STATE_STALE 3U
+
+/* Version 1: Seed pointer into btree node checksum
+ */
+#define BCACHE_BSET_VERSION 1
+
+/*
+ * This is the on disk format for btree nodes - a btree node on disk is a list
+ * of these; within each set the keys are sorted
+ */
+struct bset {
+ uint64_t csum;
+ uint64_t magic;
+ uint64_t seq;
+ uint32_t version;
+ uint32_t keys;
+
+ union {
+ struct bkey start[0];
+ uint64_t d[0];
+ };
+};
+
+/*
+ * On disk format for priorities and gens - see super.c near prio_write() for
+ * more.
+ */
+struct prio_set {
+ uint64_t csum;
+ uint64_t magic;
+ uint64_t seq;
+ uint32_t version;
+ uint32_t pad;
+
+ uint64_t next_bucket;
+
+ struct bucket_disk {
+ uint16_t prio;
+ uint8_t gen;
+ } __attribute((packed)) data[];
+};
+
+struct uuid_entry {
+ union {
+ struct {
+ uint8_t uuid[16];
+ uint8_t label[32];
+ uint32_t first_reg;
+ uint32_t last_reg;
+ uint32_t invalidated;
+
+ uint32_t flags;
+ /* Size of flash only volumes */
+ uint64_t sectors;
+ };
+
+ uint8_t pad[128];
+ };
+};
+
+BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1);
+
+#include "journal.h"
+#include "stats.h"
+struct search;
+struct btree;
+struct keybuf;
+
+struct keybuf_key {
+ struct rb_node node;
+ BKEY_PADDED(key);
+ void *private;
+};
+
+typedef bool (keybuf_pred_fn)(struct keybuf *, struct bkey *);
+
+struct keybuf {
+ keybuf_pred_fn *key_predicate;
+
+ struct bkey last_scanned;
+ spinlock_t lock;
+
+ /*
+ * Beginning and end of range in rb tree - so that we can skip taking
+ * lock and checking the rb tree when we need to check for overlapping
+ * keys.
+ */
+ struct bkey start;
+ struct bkey end;
+
+ struct rb_root keys;
+
+#define KEYBUF_NR 100
+ DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR);
+};
+
+struct bio_split_pool {
+ struct bio_set *bio_split;
+ mempool_t *bio_split_hook;
+};
+
+struct bio_split_hook {
+ struct closure cl;
+ struct bio_split_pool *p;
+ struct bio *bio;
+ bio_end_io_t *bi_end_io;
+ void *bi_private;
+};
+
+struct bcache_device {
+ struct closure cl;
+
+ struct kobject kobj;
+
+ struct cache_set *c;
+ unsigned id;
+#define BCACHEDEVNAME_SIZE 12
+ char name[BCACHEDEVNAME_SIZE];
+
+ struct gendisk *disk;
+
+ /* If nonzero, we're closing */
+ atomic_t closing;
+
+ /* If nonzero, we're detaching/unregistering from cache set */
+ atomic_t detaching;
+
+ atomic_long_t sectors_dirty;
+ unsigned long sectors_dirty_gc;
+ unsigned long sectors_dirty_last;
+ long sectors_dirty_derivative;
+
+ mempool_t *unaligned_bvec;
+ struct bio_set *bio_split;
+
+ unsigned data_csum:1;
+
+ int (*cache_miss)(struct btree *, struct search *,
+ struct bio *, unsigned);
+ int (*ioctl) (struct bcache_device *, fmode_t, unsigned, unsigned long);
+
+ struct bio_split_pool bio_split_hook;
+};
+
+struct io {
+ /* Used to track sequential IO so it can be skipped */
+ struct hlist_node hash;
+ struct list_head lru;
+
+ unsigned long jiffies;
+ unsigned sequential;
+ sector_t last;
+};
+
+struct cached_dev {
+ struct list_head list;
+ struct bcache_device disk;
+ struct block_device *bdev;
+
+ struct cache_sb sb;
+ struct bio sb_bio;
+ struct bio_vec sb_bv[1];
+ struct closure_with_waitlist sb_write;
+
+ /* Refcount on the cache set. Always nonzero when we're caching. */
+ atomic_t count;
+ struct work_struct detach;
+
+ /*
+ * Device might not be running if it's dirty and the cache set hasn't
+ * showed up yet.
+ */
+ atomic_t running;
+
+ /*
+ * Writes take a shared lock from start to finish; scanning for dirty
+ * data to refill the rb tree requires an exclusive lock.
+ */
+ struct rw_semaphore writeback_lock;
+
+ /*
+ * Nonzero, and writeback has a refcount (d->count), iff there is dirty
+ * data in the cache. Protected by writeback_lock; must have an
+ * shared lock to set and exclusive lock to clear.
+ */
+ atomic_t has_dirty;
+
+ struct ratelimit writeback_rate;
+ struct delayed_work writeback_rate_update;
+
+ /*
+ * Internal to the writeback code, so read_dirty() can keep track of
+ * where it's at.
+ */
+ sector_t last_read;
+
+ /* Number of writeback bios in flight */
+ atomic_t in_flight;
+ struct closure_with_timer writeback;
+ struct closure_waitlist writeback_wait;
+
+ struct keybuf writeback_keys;
+
+ /* For tracking sequential IO */
+#define RECENT_IO_BITS 7
+#define RECENT_IO (1 << RECENT_IO_BITS)
+ struct io io[RECENT_IO];
+ struct hlist_head io_hash[RECENT_IO + 1];
+ struct list_head io_lru;
+ spinlock_t io_lock;
+
+ struct cache_accounting accounting;
+
+ /* The rest of this all shows up in sysfs */
+ unsigned sequential_cutoff;
+ unsigned readahead;
+
+ unsigned sequential_merge:1;
+ unsigned verify:1;
+
+ unsigned writeback_metadata:1;
+ unsigned writeback_running:1;
+ unsigned char writeback_percent;
+ unsigned writeback_delay;
+
+ int writeback_rate_change;
+ int64_t writeback_rate_derivative;
+ uint64_t writeback_rate_target;
+
+ unsigned writeback_rate_update_seconds;
+ unsigned writeback_rate_d_term;
+ unsigned writeback_rate_p_term_inverse;
+ unsigned writeback_rate_d_smooth;
+};
+
+enum alloc_watermarks {
+ WATERMARK_PRIO,
+ WATERMARK_METADATA,
+ WATERMARK_MOVINGGC,
+ WATERMARK_NONE,
+ WATERMARK_MAX
+};
+
+struct cache {
+ struct cache_set *set;
+ struct cache_sb sb;
+ struct bio sb_bio;
+ struct bio_vec sb_bv[1];
+
+ struct kobject kobj;
+ struct block_device *bdev;
+
+ unsigned watermark[WATERMARK_MAX];
+
+ struct closure alloc;
+ struct workqueue_struct *alloc_workqueue;
+
+ struct closure prio;
+ struct prio_set *disk_buckets;
+
+ /*
+ * When allocating new buckets, prio_write() gets first dibs - since we
+ * may not be allocate at all without writing priorities and gens.
+ * prio_buckets[] contains the last buckets we wrote priorities to (so
+ * gc can mark them as metadata), prio_next[] contains the buckets
+ * allocated for the next prio write.
+ */
+ uint64_t *prio_buckets;
+ uint64_t *prio_last_buckets;
+
+ /*
+ * free: Buckets that are ready to be used
+ *
+ * free_inc: Incoming buckets - these are buckets that currently have
+ * cached data in them, and we can't reuse them until after we write
+ * their new gen to disk. After prio_write() finishes writing the new
+ * gens/prios, they'll be moved to the free list (and possibly discarded
+ * in the process)
+ *
+ * unused: GC found nothing pointing into these buckets (possibly
+ * because all the data they contained was overwritten), so we only
+ * need to discard them before they can be moved to the free list.
+ */
+ DECLARE_FIFO(long, free);
+ DECLARE_FIFO(long, free_inc);
+ DECLARE_FIFO(long, unused);
+
+ size_t fifo_last_bucket;
+
+ /* Allocation stuff: */
+ struct bucket *buckets;
+
+ DECLARE_HEAP(struct bucket *, heap);
+
+ /*
+ * max(gen - disk_gen) for all buckets. When it gets too big we have to
+ * call prio_write() to keep gens from wrapping.
+ */
+ uint8_t need_save_prio;
+ unsigned gc_move_threshold;
+
+ /*
+ * If nonzero, we know we aren't going to find any buckets to invalidate
+ * until a gc finishes - otherwise we could pointlessly burn a ton of
+ * cpu
+ */
+ unsigned invalidate_needs_gc:1;
+
+ bool discard; /* Get rid of? */
+
+ /*
+ * We preallocate structs for issuing discards to buckets, and keep them
+ * on this list when they're not in use; do_discard() issues discards
+ * whenever there's work to do and is called by free_some_buckets() and
+ * when a discard finishes.
+ */
+ atomic_t discards_in_flight;
+ struct list_head discards;
+
+ struct journal_device journal;
+
+ /* The rest of this all shows up in sysfs */
+#define IO_ERROR_SHIFT 20
+ atomic_t io_errors;
+ atomic_t io_count;
+
+ atomic_long_t meta_sectors_written;
+ atomic_long_t btree_sectors_written;
+ atomic_long_t sectors_written;
+
+ struct bio_split_pool bio_split_hook;
+};
+
+struct gc_stat {
+ size_t nodes;
+ size_t key_bytes;
+
+ size_t nkeys;
+ uint64_t data; /* sectors */
+ uint64_t dirty; /* sectors */
+ unsigned in_use; /* percent */
+};
+
+/*
+ * Flag bits, for how the cache set is shutting down, and what phase it's at:
+ *
+ * CACHE_SET_UNREGISTERING means we're not just shutting down, we're detaching
+ * all the backing devices first (their cached data gets invalidated, and they
+ * won't automatically reattach).
+ *
+ * CACHE_SET_STOPPING always gets set first when we're closing down a cache set;
+ * we'll continue to run normally for awhile with CACHE_SET_STOPPING set (i.e.
+ * flushing dirty data).
+ *
+ * CACHE_SET_STOPPING_2 gets set at the last phase, when it's time to shut down the
+ * allocation thread.
+ */
+#define CACHE_SET_UNREGISTERING 0
+#define CACHE_SET_STOPPING 1
+#define CACHE_SET_STOPPING_2 2
+
+struct cache_set {
+ struct closure cl;
+
+ struct list_head list;
+ struct kobject kobj;
+ struct kobject internal;
+ struct dentry *debug;
+ struct cache_accounting accounting;
+
+ unsigned long flags;
+
+ struct cache_sb sb;
+
+ struct cache *cache[MAX_CACHES_PER_SET];
+ struct cache *cache_by_alloc[MAX_CACHES_PER_SET];
+ int caches_loaded;
+
+ struct bcache_device **devices;
+ struct list_head cached_devs;
+ uint64_t cached_dev_sectors;
+ struct closure caching;
+
+ struct closure_with_waitlist sb_write;
+
+ mempool_t *search;
+ mempool_t *bio_meta;
+ struct bio_set *bio_split;
+
+ /* For the btree cache */
+ struct shrinker shrink;
+
+ /* For the allocator itself */
+ wait_queue_head_t alloc_wait;
+
+ /* For the btree cache and anything allocation related */
+ struct mutex bucket_lock;
+
+ /* log2(bucket_size), in sectors */
+ unsigned short bucket_bits;
+
+ /* log2(block_size), in sectors */
+ unsigned short block_bits;
+
+ /*
+ * Default number of pages for a new btree node - may be less than a
+ * full bucket
+ */
+ unsigned btree_pages;
+
+ /*
+ * Lists of struct btrees; lru is the list for structs that have memory
+ * allocated for actual btree node, freed is for structs that do not.
+ *
+ * We never free a struct btree, except on shutdown - we just put it on
+ * the btree_cache_freed list and reuse it later. This simplifies the
+ * code, and it doesn't cost us much memory as the memory usage is
+ * dominated by buffers that hold the actual btree node data and those
+ * can be freed - and the number of struct btrees allocated is
+ * effectively bounded.
+ *
+ * btree_cache_freeable effectively is a small cache - we use it because
+ * high order page allocations can be rather expensive, and it's quite
+ * common to delete and allocate btree nodes in quick succession. It
+ * should never grow past ~2-3 nodes in practice.
+ */
+ struct list_head btree_cache;
+ struct list_head btree_cache_freeable;
+ struct list_head btree_cache_freed;
+
+ /* Number of elements in btree_cache + btree_cache_freeable lists */
+ unsigned bucket_cache_used;
+
+ /*
+ * If we need to allocate memory for a new btree node and that
+ * allocation fails, we can cannibalize another node in the btree cache
+ * to satisfy the allocation. However, only one thread can be doing this
+ * at a time, for obvious reasons - try_harder and try_wait are
+ * basically a lock for this that we can wait on asynchronously. The
+ * btree_root() macro releases the lock when it returns.
+ */
+ struct closure *try_harder;
+ struct closure_waitlist try_wait;
+ uint64_t try_harder_start;
+
+ /*
+ * When we free a btree node, we increment the gen of the bucket the
+ * node is in - but we can't rewrite the prios and gens until we
+ * finished whatever it is we were doing, otherwise after a crash the
+ * btree node would be freed but for say a split, we might not have the
+ * pointers to the new nodes inserted into the btree yet.
+ *
+ * This is a refcount that blocks prio_write() until the new keys are
+ * written.
+ */
+ atomic_t prio_blocked;
+ struct closure_waitlist bucket_wait;
+
+ /*
+ * For any bio we don't skip we subtract the number of sectors from
+ * rescale; when it hits 0 we rescale all the bucket priorities.
+ */
+ atomic_t rescale;
+ /*
+ * When we invalidate buckets, we use both the priority and the amount
+ * of good data to determine which buckets to reuse first - to weight
+ * those together consistently we keep track of the smallest nonzero
+ * priority of any bucket.
+ */
+ uint16_t min_prio;
+
+ /*
+ * max(gen - gc_gen) for all buckets. When it gets too big we have to gc
+ * to keep gens from wrapping around.
+ */
+ uint8_t need_gc;
+ struct gc_stat gc_stats;
+ size_t nbuckets;
+
+ struct closure_with_waitlist gc;
+ /* Where in the btree gc currently is */
+ struct bkey gc_done;
+
+ /*
+ * The allocation code needs gc_mark in struct bucket to be correct, but
+ * it's not while a gc is in progress. Protected by bucket_lock.
+ */
+ int gc_mark_valid;
+
+ /* Counts how many sectors bio_insert has added to the cache */
+ atomic_t sectors_to_gc;
+
+ struct closure moving_gc;
+ struct closure_waitlist moving_gc_wait;
+ struct keybuf moving_gc_keys;
+ /* Number of moving GC bios in flight */
+ atomic_t in_flight;
+
+ struct btree *root;
+
+#ifdef CONFIG_BCACHE_DEBUG
+ struct btree *verify_data;
+ struct mutex verify_lock;
+#endif
+
+ unsigned nr_uuids;
+ struct uuid_entry *uuids;
+ BKEY_PADDED(uuid_bucket);
+ struct closure_with_waitlist uuid_write;
+
+ /*
+ * A btree node on disk could have too many bsets for an iterator to fit
+ * on the stack - this is a single element mempool for btree_read_work()
+ */
+ struct mutex fill_lock;
+ struct btree_iter *fill_iter;
+
+ /*
+ * btree_sort() is a merge sort and requires temporary space - single
+ * element mempool
+ */
+ struct mutex sort_lock;
+ struct bset *sort;
+
+ /* List of buckets we're currently writing data to */
+ struct list_head data_buckets;
+ spinlock_t data_bucket_lock;
+
+ struct journal journal;
+
+#define CONGESTED_MAX 1024
+ unsigned congested_last_us;
+ atomic_t congested;
+
+ /* The rest of this all shows up in sysfs */
+ unsigned congested_read_threshold_us;
+ unsigned congested_write_threshold_us;
+
+ spinlock_t sort_time_lock;
+ struct time_stats sort_time;
+ struct time_stats btree_gc_time;
+ struct time_stats btree_split_time;
+ spinlock_t btree_read_time_lock;
+ struct time_stats btree_read_time;
+ struct time_stats try_harder_time;
+
+ atomic_long_t cache_read_races;
+ atomic_long_t writeback_keys_done;
+ atomic_long_t writeback_keys_failed;
+ unsigned error_limit;
+ unsigned error_decay;
+ unsigned short journal_delay_ms;
+ unsigned verify:1;
+ unsigned key_merging_disabled:1;
+ unsigned gc_always_rewrite:1;
+ unsigned shrinker_disabled:1;
+ unsigned copy_gc_enabled:1;
+
+#define BUCKET_HASH_BITS 12
+ struct hlist_head bucket_hash[1 << BUCKET_HASH_BITS];
+};
+
+static inline bool key_merging_disabled(struct cache_set *c)
+{
+#ifdef CONFIG_BCACHE_DEBUG
+ return c->key_merging_disabled;
+#else
+ return 0;
+#endif
+}
+
+struct bbio {
+ unsigned submit_time_us;
+ union {
+ struct bkey key;
+ uint64_t _pad[3];
+ /*
+ * We only need pad = 3 here because we only ever carry around a
+ * single pointer - i.e. the pointer we're doing io to/from.
+ */
+ };
+ struct bio bio;
+};
+
+static inline unsigned local_clock_us(void)
+{
+ return local_clock() >> 10;
+}
+
+#define MAX_BSETS 4U
+
+#define BTREE_PRIO USHRT_MAX
+#define INITIAL_PRIO 32768
+
+#define btree_bytes(c) ((c)->btree_pages * PAGE_SIZE)
+#define btree_blocks(b) \
+ ((unsigned) (KEY_SIZE(&b->key) >> (b)->c->block_bits))
+
+#define btree_default_blocks(c) \
+ ((unsigned) ((PAGE_SECTORS * (c)->btree_pages) >> (c)->block_bits))
+
+#define bucket_pages(c) ((c)->sb.bucket_size / PAGE_SECTORS)
+#define bucket_bytes(c) ((c)->sb.bucket_size << 9)
+#define block_bytes(c) ((c)->sb.block_size << 9)
+
+#define __set_bytes(i, k) (sizeof(*(i)) + (k) * sizeof(uint64_t))
+#define set_bytes(i) __set_bytes(i, i->keys)
+
+#define __set_blocks(i, k, c) DIV_ROUND_UP(__set_bytes(i, k), block_bytes(c))
+#define set_blocks(i, c) __set_blocks(i, (i)->keys, c)
+
+#define node(i, j) ((struct bkey *) ((i)->d + (j)))
+#define end(i) node(i, (i)->keys)
+
+#define index(i, b) \
+ ((size_t) (((void *) i - (void *) (b)->sets[0].data) / \
+ block_bytes(b->c)))
+
+#define btree_data_space(b) (PAGE_SIZE << (b)->page_order)
+
+#define prios_per_bucket(c) \
+ ((bucket_bytes(c) - sizeof(struct prio_set)) / \
+ sizeof(struct bucket_disk))
+#define prio_buckets(c) \
+ DIV_ROUND_UP((size_t) (c)->sb.nbuckets, prios_per_bucket(c))
+
+#define JSET_MAGIC 0x245235c1a3625032ULL
+#define PSET_MAGIC 0x6750e15f87337f91ULL
+#define BSET_MAGIC 0x90135c78b99e07f5ULL
+
+#define jset_magic(c) ((c)->sb.set_magic ^ JSET_MAGIC)
+#define pset_magic(c) ((c)->sb.set_magic ^ PSET_MAGIC)
+#define bset_magic(c) ((c)->sb.set_magic ^ BSET_MAGIC)
+
+/* Bkey fields: all units are in sectors */
+
+#define KEY_FIELD(name, field, offset, size) \
+ BITMASK(name, struct bkey, field, offset, size)
+
+#define PTR_FIELD(name, offset, size) \
+ static inline uint64_t name(const struct bkey *k, unsigned i) \
+ { return (k->ptr[i] >> offset) & ~(((uint64_t) ~0) << size); } \
+ \
+ static inline void SET_##name(struct bkey *k, unsigned i, uint64_t v)\
+ { \
+ k->ptr[i] &= ~(~((uint64_t) ~0 << size) << offset); \
+ k->ptr[i] |= v << offset; \
+ }
+
+KEY_FIELD(KEY_PTRS, high, 60, 3)
+KEY_FIELD(HEADER_SIZE, high, 58, 2)
+KEY_FIELD(KEY_CSUM, high, 56, 2)
+KEY_FIELD(KEY_PINNED, high, 55, 1)
+KEY_FIELD(KEY_DIRTY, high, 36, 1)
+
+KEY_FIELD(KEY_SIZE, high, 20, 16)
+KEY_FIELD(KEY_INODE, high, 0, 20)
+
+/* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
+
+static inline uint64_t KEY_OFFSET(const struct bkey *k)
+{
+ return k->low;
+}
+
+static inline void SET_KEY_OFFSET(struct bkey *k, uint64_t v)
+{
+ k->low = v;
+}
+
+PTR_FIELD(PTR_DEV, 51, 12)
+PTR_FIELD(PTR_OFFSET, 8, 43)
+PTR_FIELD(PTR_GEN, 0, 8)
+
+#define PTR_CHECK_DEV ((1 << 12) - 1)
+
+#define PTR(gen, offset, dev) \
+ ((((uint64_t) dev) << 51) | ((uint64_t) offset) << 8 | gen)
+
+static inline size_t sector_to_bucket(struct cache_set *c, sector_t s)
+{
+ return s >> c->bucket_bits;
+}
+
+static inline sector_t bucket_to_sector(struct cache_set *c, size_t b)
+{
+ return ((sector_t) b) << c->bucket_bits;
+}
+
+static inline sector_t bucket_remainder(struct cache_set *c, sector_t s)
+{
+ return s & (c->sb.bucket_size - 1);
+}
+
+static inline struct cache *PTR_CACHE(struct cache_set *c,
+ const struct bkey *k,
+ unsigned ptr)
+{
+ return c->cache[PTR_DEV(k, ptr)];
+}
+
+static inline size_t PTR_BUCKET_NR(struct cache_set *c,
+ const struct bkey *k,
+ unsigned ptr)
+{
+ return sector_to_bucket(c, PTR_OFFSET(k, ptr));
+}
+
+static inline struct bucket *PTR_BUCKET(struct cache_set *c,
+ const struct bkey *k,
+ unsigned ptr)
+{
+ return PTR_CACHE(c, k, ptr)->buckets + PTR_BUCKET_NR(c, k, ptr);
+}
+
+/* Btree key macros */
+
+/*
+ * The high bit being set is a relic from when we used it to do binary
+ * searches - it told you where a key started. It's not used anymore,
+ * and can probably be safely dropped.
+ */
+#define KEY(dev, sector, len) (struct bkey) \
+{ \
+ .high = (1ULL << 63) | ((uint64_t) (len) << 20) | (dev), \
+ .low = (sector) \
+}
+
+static inline void bkey_init(struct bkey *k)
+{
+ *k = KEY(0, 0, 0);
+}
+
+#define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k))
+#define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0)
+#define MAX_KEY KEY(~(~0 << 20), ((uint64_t) ~0) >> 1, 0)
+#define ZERO_KEY KEY(0, 0, 0)
+
+/*
+ * This is used for various on disk data structures - cache_sb, prio_set, bset,
+ * jset: The checksum is _always_ the first 8 bytes of these structs
+ */
+#define csum_set(i) \
+ crc64(((void *) (i)) + sizeof(uint64_t), \
+ ((void *) end(i)) - (((void *) (i)) + sizeof(uint64_t)))
+
+/* Error handling macros */
+
+#define btree_bug(b, ...) \
+do { \
+ if (bch_cache_set_error((b)->c, __VA_ARGS__)) \
+ dump_stack(); \
+} while (0)
+
+#define cache_bug(c, ...) \
+do { \
+ if (bch_cache_set_error(c, __VA_ARGS__)) \
+ dump_stack(); \
+} while (0)
+
+#define btree_bug_on(cond, b, ...) \
+do { \
+ if (cond) \
+ btree_bug(b, __VA_ARGS__); \
+} while (0)
+
+#define cache_bug_on(cond, c, ...) \
+do { \
+ if (cond) \
+ cache_bug(c, __VA_ARGS__); \
+} while (0)
+
+#define cache_set_err_on(cond, c, ...) \
+do { \
+ if (cond) \
+ bch_cache_set_error(c, __VA_ARGS__); \
+} while (0)
+
+/* Looping macros */
+
+#define for_each_cache(ca, cs, iter) \
+ for (iter = 0; ca = cs->cache[iter], iter < (cs)->sb.nr_in_set; iter++)
+
+#define for_each_bucket(b, ca) \
+ for (b = (ca)->buckets + (ca)->sb.first_bucket; \
+ b < (ca)->buckets + (ca)->sb.nbuckets; b++)
+
+static inline void __bkey_put(struct cache_set *c, struct bkey *k)
+{
+ unsigned i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);
+}
+
+/* Blktrace macros */
+
+#define blktrace_msg(c, fmt, ...) \
+do { \
+ struct request_queue *q = bdev_get_queue(c->bdev); \
+ if (q) \
+ blk_add_trace_msg(q, fmt, ##__VA_ARGS__); \
+} while (0)
+
+#define blktrace_msg_all(s, fmt, ...) \
+do { \
+ struct cache *_c; \
+ unsigned i; \
+ for_each_cache(_c, (s), i) \
+ blktrace_msg(_c, fmt, ##__VA_ARGS__); \
+} while (0)
+
+static inline void cached_dev_put(struct cached_dev *dc)
+{
+ if (atomic_dec_and_test(&dc->count))
+ schedule_work(&dc->detach);
+}
+
+static inline bool cached_dev_get(struct cached_dev *dc)
+{
+ if (!atomic_inc_not_zero(&dc->count))
+ return false;
+
+ /* Paired with the mb in cached_dev_attach */
+ smp_mb__after_atomic_inc();
+ return true;
+}
+
+/*
+ * bucket_gc_gen() returns the difference between the bucket's current gen and
+ * the oldest gen of any pointer into that bucket in the btree (last_gc).
+ *
+ * bucket_disk_gen() returns the difference between the current gen and the gen
+ * on disk; they're both used to make sure gens don't wrap around.
+ */
+
+static inline uint8_t bucket_gc_gen(struct bucket *b)
+{
+ return b->gen - b->last_gc;
+}
+
+static inline uint8_t bucket_disk_gen(struct bucket *b)
+{
+ return b->gen - b->disk_gen;
+}
+
+#define BUCKET_GC_GEN_MAX 96U
+#define BUCKET_DISK_GEN_MAX 64U
+
+#define kobj_attribute_write(n, fn) \
+ static struct kobj_attribute ksysfs_##n = __ATTR(n, S_IWUSR, NULL, fn)
+
+#define kobj_attribute_rw(n, show, store) \
+ static struct kobj_attribute ksysfs_##n = \
+ __ATTR(n, S_IWUSR|S_IRUSR, show, store)
+
+/* Forward declarations */
+
+void bch_writeback_queue(struct cached_dev *);
+void bch_writeback_add(struct cached_dev *, unsigned);
+
+void bch_count_io_errors(struct cache *, int, const char *);
+void bch_bbio_count_io_errors(struct cache_set *, struct bio *,
+ int, const char *);
+void bch_bbio_endio(struct cache_set *, struct bio *, int, const char *);
+void bch_bbio_free(struct bio *, struct cache_set *);
+struct bio *bch_bbio_alloc(struct cache_set *);
+
+struct bio *bch_bio_split(struct bio *, int, gfp_t, struct bio_set *);
+void bch_generic_make_request(struct bio *, struct bio_split_pool *);
+void __bch_submit_bbio(struct bio *, struct cache_set *);
+void bch_submit_bbio(struct bio *, struct cache_set *, struct bkey *, unsigned);
+
+uint8_t bch_inc_gen(struct cache *, struct bucket *);
+void bch_rescale_priorities(struct cache_set *, int);
+bool bch_bucket_add_unused(struct cache *, struct bucket *);
+void bch_allocator_thread(struct closure *);
+
+long bch_bucket_alloc(struct cache *, unsigned, struct closure *);
+void bch_bucket_free(struct cache_set *, struct bkey *);
+
+int __bch_bucket_alloc_set(struct cache_set *, unsigned,
+ struct bkey *, int, struct closure *);
+int bch_bucket_alloc_set(struct cache_set *, unsigned,
+ struct bkey *, int, struct closure *);
+
+__printf(2, 3)
+bool bch_cache_set_error(struct cache_set *, const char *, ...);
+
+void bch_prio_write(struct cache *);
+void bch_write_bdev_super(struct cached_dev *, struct closure *);
+
+extern struct workqueue_struct *bcache_wq, *bch_gc_wq;
+extern const char * const bch_cache_modes[];
+extern struct mutex bch_register_lock;
+extern struct list_head bch_cache_sets;
+
+extern struct kobj_type bch_cached_dev_ktype;
+extern struct kobj_type bch_flash_dev_ktype;
+extern struct kobj_type bch_cache_set_ktype;
+extern struct kobj_type bch_cache_set_internal_ktype;
+extern struct kobj_type bch_cache_ktype;
+
+void bch_cached_dev_release(struct kobject *);
+void bch_flash_dev_release(struct kobject *);
+void bch_cache_set_release(struct kobject *);
+void bch_cache_release(struct kobject *);
+
+int bch_uuid_write(struct cache_set *);
+void bcache_write_super(struct cache_set *);
+
+int bch_flash_dev_create(struct cache_set *c, uint64_t size);
+
+int bch_cached_dev_attach(struct cached_dev *, struct cache_set *);
+void bch_cached_dev_detach(struct cached_dev *);
+void bch_cached_dev_run(struct cached_dev *);
+void bcache_device_stop(struct bcache_device *);
+
+void bch_cache_set_unregister(struct cache_set *);
+void bch_cache_set_stop(struct cache_set *);
+
+struct cache_set *bch_cache_set_alloc(struct cache_sb *);
+void bch_btree_cache_free(struct cache_set *);
+int bch_btree_cache_alloc(struct cache_set *);
+void bch_writeback_init_cached_dev(struct cached_dev *);
+void bch_moving_init_cache_set(struct cache_set *);
+
+void bch_cache_allocator_exit(struct cache *ca);
+int bch_cache_allocator_init(struct cache *ca);
+
+void bch_debug_exit(void);
+int bch_debug_init(struct kobject *);
+void bch_writeback_exit(void);
+int bch_writeback_init(void);
+void bch_request_exit(void);
+int bch_request_init(void);
+void bch_btree_exit(void);
+int bch_btree_init(void);
+
+#endif /* _BCACHE_H */
--- /dev/null
+/*
+ * Code for working with individual keys, and sorted sets of keys with in a
+ * btree node
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+
+#include <linux/random.h>
+
+/* Keylists */
+
+void bch_keylist_copy(struct keylist *dest, struct keylist *src)
+{
+ *dest = *src;
+
+ if (src->list == src->d) {
+ size_t n = (uint64_t *) src->top - src->d;
+ dest->top = (struct bkey *) &dest->d[n];
+ dest->list = dest->d;
+ }
+}
+
+int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c)
+{
+ unsigned oldsize = (uint64_t *) l->top - l->list;
+ unsigned newsize = oldsize + 2 + nptrs;
+ uint64_t *new;
+
+ /* The journalling code doesn't handle the case where the keys to insert
+ * is bigger than an empty write: If we just return -ENOMEM here,
+ * bio_insert() and bio_invalidate() will insert the keys created so far
+ * and finish the rest when the keylist is empty.
+ */
+ if (newsize * sizeof(uint64_t) > block_bytes(c) - sizeof(struct jset))
+ return -ENOMEM;
+
+ newsize = roundup_pow_of_two(newsize);
+
+ if (newsize <= KEYLIST_INLINE ||
+ roundup_pow_of_two(oldsize) == newsize)
+ return 0;
+
+ new = krealloc(l->list == l->d ? NULL : l->list,
+ sizeof(uint64_t) * newsize, GFP_NOIO);
+
+ if (!new)
+ return -ENOMEM;
+
+ if (l->list == l->d)
+ memcpy(new, l->list, sizeof(uint64_t) * KEYLIST_INLINE);
+
+ l->list = new;
+ l->top = (struct bkey *) (&l->list[oldsize]);
+
+ return 0;
+}
+
+struct bkey *bch_keylist_pop(struct keylist *l)
+{
+ struct bkey *k = l->bottom;
+
+ if (k == l->top)
+ return NULL;
+
+ while (bkey_next(k) != l->top)
+ k = bkey_next(k);
+
+ return l->top = k;
+}
+
+/* Pointer validation */
+
+bool __bch_ptr_invalid(struct cache_set *c, int level, const struct bkey *k)
+{
+ unsigned i;
+
+ if (level && (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k)))
+ goto bad;
+
+ if (!level && KEY_SIZE(k) > KEY_OFFSET(k))
+ goto bad;
+
+ if (!KEY_SIZE(k))
+ return true;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i)) {
+ struct cache *ca = PTR_CACHE(c, k, i);
+ size_t bucket = PTR_BUCKET_NR(c, k, i);
+ size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
+
+ if (KEY_SIZE(k) + r > c->sb.bucket_size ||
+ bucket < ca->sb.first_bucket ||
+ bucket >= ca->sb.nbuckets)
+ goto bad;
+ }
+
+ return false;
+bad:
+ cache_bug(c, "spotted bad key %s: %s", pkey(k), bch_ptr_status(c, k));
+ return true;
+}
+
+bool bch_ptr_bad(struct btree *b, const struct bkey *k)
+{
+ struct bucket *g;
+ unsigned i, stale;
+
+ if (!bkey_cmp(k, &ZERO_KEY) ||
+ !KEY_PTRS(k) ||
+ bch_ptr_invalid(b, k))
+ return true;
+
+ if (KEY_PTRS(k) && PTR_DEV(k, 0) == PTR_CHECK_DEV)
+ return true;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(b->c, k, i)) {
+ g = PTR_BUCKET(b->c, k, i);
+ stale = ptr_stale(b->c, k, i);
+
+ btree_bug_on(stale > 96, b,
+ "key too stale: %i, need_gc %u",
+ stale, b->c->need_gc);
+
+ btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
+ b, "stale dirty pointer");
+
+ if (stale)
+ return true;
+
+#ifdef CONFIG_BCACHE_EDEBUG
+ if (!mutex_trylock(&b->c->bucket_lock))
+ continue;
+
+ if (b->level) {
+ if (KEY_DIRTY(k) ||
+ g->prio != BTREE_PRIO ||
+ (b->c->gc_mark_valid &&
+ GC_MARK(g) != GC_MARK_METADATA))
+ goto bug;
+
+ } else {
+ if (g->prio == BTREE_PRIO)
+ goto bug;
+
+ if (KEY_DIRTY(k) &&
+ b->c->gc_mark_valid &&
+ GC_MARK(g) != GC_MARK_DIRTY)
+ goto bug;
+ }
+ mutex_unlock(&b->c->bucket_lock);
+#endif
+ }
+
+ return false;
+#ifdef CONFIG_BCACHE_EDEBUG
+bug:
+ mutex_unlock(&b->c->bucket_lock);
+ btree_bug(b, "inconsistent pointer %s: bucket %li pin %i "
+ "prio %i gen %i last_gc %i mark %llu gc_gen %i", pkey(k),
+ PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
+ g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
+ return true;
+#endif
+}
+
+/* Key/pointer manipulation */
+
+void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
+ unsigned i)
+{
+ BUG_ON(i > KEY_PTRS(src));
+
+ /* Only copy the header, key, and one pointer. */
+ memcpy(dest, src, 2 * sizeof(uint64_t));
+ dest->ptr[0] = src->ptr[i];
+ SET_KEY_PTRS(dest, 1);
+ /* We didn't copy the checksum so clear that bit. */
+ SET_KEY_CSUM(dest, 0);
+}
+
+bool __bch_cut_front(const struct bkey *where, struct bkey *k)
+{
+ unsigned i, len = 0;
+
+ if (bkey_cmp(where, &START_KEY(k)) <= 0)
+ return false;
+
+ if (bkey_cmp(where, k) < 0)
+ len = KEY_OFFSET(k) - KEY_OFFSET(where);
+ else
+ bkey_copy_key(k, where);
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
+
+ BUG_ON(len > KEY_SIZE(k));
+ SET_KEY_SIZE(k, len);
+ return true;
+}
+
+bool __bch_cut_back(const struct bkey *where, struct bkey *k)
+{
+ unsigned len = 0;
+
+ if (bkey_cmp(where, k) >= 0)
+ return false;
+
+ BUG_ON(KEY_INODE(where) != KEY_INODE(k));
+
+ if (bkey_cmp(where, &START_KEY(k)) > 0)
+ len = KEY_OFFSET(where) - KEY_START(k);
+
+ bkey_copy_key(k, where);
+
+ BUG_ON(len > KEY_SIZE(k));
+ SET_KEY_SIZE(k, len);
+ return true;
+}
+
+static uint64_t merge_chksums(struct bkey *l, struct bkey *r)
+{
+ return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) &
+ ~((uint64_t)1 << 63);
+}
+
+/* Tries to merge l and r: l should be lower than r
+ * Returns true if we were able to merge. If we did merge, l will be the merged
+ * key, r will be untouched.
+ */
+bool bch_bkey_try_merge(struct btree *b, struct bkey *l, struct bkey *r)
+{
+ unsigned i;
+
+ if (key_merging_disabled(b->c))
+ return false;
+
+ if (KEY_PTRS(l) != KEY_PTRS(r) ||
+ KEY_DIRTY(l) != KEY_DIRTY(r) ||
+ bkey_cmp(l, &START_KEY(r)))
+ return false;
+
+ for (i = 0; i < KEY_PTRS(l); i++)
+ if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
+ PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))
+ return false;
+
+ /* Keys with no pointers aren't restricted to one bucket and could
+ * overflow KEY_SIZE
+ */
+ if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) {
+ SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l));
+ SET_KEY_SIZE(l, USHRT_MAX);
+
+ bch_cut_front(l, r);
+ return false;
+ }
+
+ if (KEY_CSUM(l)) {
+ if (KEY_CSUM(r))
+ l->ptr[KEY_PTRS(l)] = merge_chksums(l, r);
+ else
+ SET_KEY_CSUM(l, 0);
+ }
+
+ SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r));
+ SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r));
+
+ return true;
+}
+
+/* Binary tree stuff for auxiliary search trees */
+
+static unsigned inorder_next(unsigned j, unsigned size)
+{
+ if (j * 2 + 1 < size) {
+ j = j * 2 + 1;
+
+ while (j * 2 < size)
+ j *= 2;
+ } else
+ j >>= ffz(j) + 1;
+
+ return j;
+}
+
+static unsigned inorder_prev(unsigned j, unsigned size)
+{
+ if (j * 2 < size) {
+ j = j * 2;
+
+ while (j * 2 + 1 < size)
+ j = j * 2 + 1;
+ } else
+ j >>= ffs(j);
+
+ return j;
+}
+
+/* I have no idea why this code works... and I'm the one who wrote it
+ *
+ * However, I do know what it does:
+ * Given a binary tree constructed in an array (i.e. how you normally implement
+ * a heap), it converts a node in the tree - referenced by array index - to the
+ * index it would have if you did an inorder traversal.
+ *
+ * Also tested for every j, size up to size somewhere around 6 million.
+ *
+ * The binary tree starts at array index 1, not 0
+ * extra is a function of size:
+ * extra = (size - rounddown_pow_of_two(size - 1)) << 1;
+ */
+static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra)
+{
+ unsigned b = fls(j);
+ unsigned shift = fls(size - 1) - b;
+
+ j ^= 1U << (b - 1);
+ j <<= 1;
+ j |= 1;
+ j <<= shift;
+
+ if (j > extra)
+ j -= (j - extra) >> 1;
+
+ return j;
+}
+
+static unsigned to_inorder(unsigned j, struct bset_tree *t)
+{
+ return __to_inorder(j, t->size, t->extra);
+}
+
+static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra)
+{
+ unsigned shift;
+
+ if (j > extra)
+ j += j - extra;
+
+ shift = ffs(j);
+
+ j >>= shift;
+ j |= roundup_pow_of_two(size) >> shift;
+
+ return j;
+}
+
+static unsigned inorder_to_tree(unsigned j, struct bset_tree *t)
+{
+ return __inorder_to_tree(j, t->size, t->extra);
+}
+
+#if 0
+void inorder_test(void)
+{
+ unsigned long done = 0;
+ ktime_t start = ktime_get();
+
+ for (unsigned size = 2;
+ size < 65536000;
+ size++) {
+ unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1;
+ unsigned i = 1, j = rounddown_pow_of_two(size - 1);
+
+ if (!(size % 4096))
+ printk(KERN_NOTICE "loop %u, %llu per us\n", size,
+ done / ktime_us_delta(ktime_get(), start));
+
+ while (1) {
+ if (__inorder_to_tree(i, size, extra) != j)
+ panic("size %10u j %10u i %10u", size, j, i);
+
+ if (__to_inorder(j, size, extra) != i)
+ panic("size %10u j %10u i %10u", size, j, i);
+
+ if (j == rounddown_pow_of_two(size) - 1)
+ break;
+
+ BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
+
+ j = inorder_next(j, size);
+ i++;
+ }
+
+ done += size - 1;
+ }
+}
+#endif
+
+/*
+ * Cacheline/offset <-> bkey pointer arithmatic:
+ *
+ * t->tree is a binary search tree in an array; each node corresponds to a key
+ * in one cacheline in t->set (BSET_CACHELINE bytes).
+ *
+ * This means we don't have to store the full index of the key that a node in
+ * the binary tree points to; to_inorder() gives us the cacheline, and then
+ * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
+ *
+ * cacheline_to_bkey() and friends abstract out all the pointer arithmatic to
+ * make this work.
+ *
+ * To construct the bfloat for an arbitrary key we need to know what the key
+ * immediately preceding it is: we have to check if the two keys differ in the
+ * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
+ * of the previous key so we can walk backwards to it from t->tree[j]'s key.
+ */
+
+static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline,
+ unsigned offset)
+{
+ return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
+}
+
+static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
+{
+ return ((void *) k - (void *) t->data) / BSET_CACHELINE;
+}
+
+static unsigned bkey_to_cacheline_offset(struct bkey *k)
+{
+ return ((size_t) k & (BSET_CACHELINE - 1)) / sizeof(uint64_t);
+}
+
+static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j)
+{
+ return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
+}
+
+static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j)
+{
+ return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
+}
+
+/*
+ * For the write set - the one we're currently inserting keys into - we don't
+ * maintain a full search tree, we just keep a simple lookup table in t->prev.
+ */
+static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
+{
+ return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
+}
+
+static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
+{
+#ifdef CONFIG_X86_64
+ asm("shrd %[shift],%[high],%[low]"
+ : [low] "+Rm" (low)
+ : [high] "R" (high),
+ [shift] "ci" (shift)
+ : "cc");
+#else
+ low >>= shift;
+ low |= (high << 1) << (63U - shift);
+#endif
+ return low;
+}
+
+static inline unsigned bfloat_mantissa(const struct bkey *k,
+ struct bkey_float *f)
+{
+ const uint64_t *p = &k->low - (f->exponent >> 6);
+ return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
+}
+
+static void make_bfloat(struct bset_tree *t, unsigned j)
+{
+ struct bkey_float *f = &t->tree[j];
+ struct bkey *m = tree_to_bkey(t, j);
+ struct bkey *p = tree_to_prev_bkey(t, j);
+
+ struct bkey *l = is_power_of_2(j)
+ ? t->data->start
+ : tree_to_prev_bkey(t, j >> ffs(j));
+
+ struct bkey *r = is_power_of_2(j + 1)
+ ? node(t->data, t->data->keys - bkey_u64s(&t->end))
+ : tree_to_bkey(t, j >> (ffz(j) + 1));
+
+ BUG_ON(m < l || m > r);
+ BUG_ON(bkey_next(p) != m);
+
+ if (KEY_INODE(l) != KEY_INODE(r))
+ f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64;
+ else
+ f->exponent = fls64(r->low ^ l->low);
+
+ f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0);
+
+ /*
+ * Setting f->exponent = 127 flags this node as failed, and causes the
+ * lookup code to fall back to comparing against the original key.
+ */
+
+ if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f))
+ f->mantissa = bfloat_mantissa(m, f) - 1;
+ else
+ f->exponent = 127;
+}
+
+static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
+{
+ if (t != b->sets) {
+ unsigned j = roundup(t[-1].size,
+ 64 / sizeof(struct bkey_float));
+
+ t->tree = t[-1].tree + j;
+ t->prev = t[-1].prev + j;
+ }
+
+ while (t < b->sets + MAX_BSETS)
+ t++->size = 0;
+}
+
+static void bset_build_unwritten_tree(struct btree *b)
+{
+ struct bset_tree *t = b->sets + b->nsets;
+
+ bset_alloc_tree(b, t);
+
+ if (t->tree != b->sets->tree + bset_tree_space(b)) {
+ t->prev[0] = bkey_to_cacheline_offset(t->data->start);
+ t->size = 1;
+ }
+}
+
+static void bset_build_written_tree(struct btree *b)
+{
+ struct bset_tree *t = b->sets + b->nsets;
+ struct bkey *k = t->data->start;
+ unsigned j, cacheline = 1;
+
+ bset_alloc_tree(b, t);
+
+ t->size = min_t(unsigned,
+ bkey_to_cacheline(t, end(t->data)),
+ b->sets->tree + bset_tree_space(b) - t->tree);
+
+ if (t->size < 2) {
+ t->size = 0;
+ return;
+ }
+
+ t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
+
+ /* First we figure out where the first key in each cacheline is */
+ for (j = inorder_next(0, t->size);
+ j;
+ j = inorder_next(j, t->size)) {
+ while (bkey_to_cacheline(t, k) != cacheline)
+ k = bkey_next(k);
+
+ t->prev[j] = bkey_u64s(k);
+ k = bkey_next(k);
+ cacheline++;
+ t->tree[j].m = bkey_to_cacheline_offset(k);
+ }
+
+ while (bkey_next(k) != end(t->data))
+ k = bkey_next(k);
+
+ t->end = *k;
+
+ /* Then we build the tree */
+ for (j = inorder_next(0, t->size);
+ j;
+ j = inorder_next(j, t->size))
+ make_bfloat(t, j);
+}
+
+void bch_bset_fix_invalidated_key(struct btree *b, struct bkey *k)
+{
+ struct bset_tree *t;
+ unsigned inorder, j = 1;
+
+ for (t = b->sets; t <= &b->sets[b->nsets]; t++)
+ if (k < end(t->data))
+ goto found_set;
+
+ BUG();
+found_set:
+ if (!t->size || !bset_written(b, t))
+ return;
+
+ inorder = bkey_to_cacheline(t, k);
+
+ if (k == t->data->start)
+ goto fix_left;
+
+ if (bkey_next(k) == end(t->data)) {
+ t->end = *k;
+ goto fix_right;
+ }
+
+ j = inorder_to_tree(inorder, t);
+
+ if (j &&
+ j < t->size &&
+ k == tree_to_bkey(t, j))
+fix_left: do {
+ make_bfloat(t, j);
+ j = j * 2;
+ } while (j < t->size);
+
+ j = inorder_to_tree(inorder + 1, t);
+
+ if (j &&
+ j < t->size &&
+ k == tree_to_prev_bkey(t, j))
+fix_right: do {
+ make_bfloat(t, j);
+ j = j * 2 + 1;
+ } while (j < t->size);
+}
+
+void bch_bset_fix_lookup_table(struct btree *b, struct bkey *k)
+{
+ struct bset_tree *t = &b->sets[b->nsets];
+ unsigned shift = bkey_u64s(k);
+ unsigned j = bkey_to_cacheline(t, k);
+
+ /* We're getting called from btree_split() or btree_gc, just bail out */
+ if (!t->size)
+ return;
+
+ /* k is the key we just inserted; we need to find the entry in the
+ * lookup table for the first key that is strictly greater than k:
+ * it's either k's cacheline or the next one
+ */
+ if (j < t->size &&
+ table_to_bkey(t, j) <= k)
+ j++;
+
+ /* Adjust all the lookup table entries, and find a new key for any that
+ * have gotten too big
+ */
+ for (; j < t->size; j++) {
+ t->prev[j] += shift;
+
+ if (t->prev[j] > 7) {
+ k = table_to_bkey(t, j - 1);
+
+ while (k < cacheline_to_bkey(t, j, 0))
+ k = bkey_next(k);
+
+ t->prev[j] = bkey_to_cacheline_offset(k);
+ }
+ }
+
+ if (t->size == b->sets->tree + bset_tree_space(b) - t->tree)
+ return;
+
+ /* Possibly add a new entry to the end of the lookup table */
+
+ for (k = table_to_bkey(t, t->size - 1);
+ k != end(t->data);
+ k = bkey_next(k))
+ if (t->size == bkey_to_cacheline(t, k)) {
+ t->prev[t->size] = bkey_to_cacheline_offset(k);
+ t->size++;
+ }
+}
+
+void bch_bset_init_next(struct btree *b)
+{
+ struct bset *i = write_block(b);
+
+ if (i != b->sets[0].data) {
+ b->sets[++b->nsets].data = i;
+ i->seq = b->sets[0].data->seq;
+ } else
+ get_random_bytes(&i->seq, sizeof(uint64_t));
+
+ i->magic = bset_magic(b->c);
+ i->version = 0;
+ i->keys = 0;
+
+ bset_build_unwritten_tree(b);
+}
+
+struct bset_search_iter {
+ struct bkey *l, *r;
+};
+
+static struct bset_search_iter bset_search_write_set(struct btree *b,
+ struct bset_tree *t,
+ const struct bkey *search)
+{
+ unsigned li = 0, ri = t->size;
+
+ BUG_ON(!b->nsets &&
+ t->size < bkey_to_cacheline(t, end(t->data)));
+
+ while (li + 1 != ri) {
+ unsigned m = (li + ri) >> 1;
+
+ if (bkey_cmp(table_to_bkey(t, m), search) > 0)
+ ri = m;
+ else
+ li = m;
+ }
+
+ return (struct bset_search_iter) {
+ table_to_bkey(t, li),
+ ri < t->size ? table_to_bkey(t, ri) : end(t->data)
+ };
+}
+
+static struct bset_search_iter bset_search_tree(struct btree *b,
+ struct bset_tree *t,
+ const struct bkey *search)
+{
+ struct bkey *l, *r;
+ struct bkey_float *f;
+ unsigned inorder, j, n = 1;
+
+ do {
+ unsigned p = n << 4;
+ p &= ((int) (p - t->size)) >> 31;
+
+ prefetch(&t->tree[p]);
+
+ j = n;
+ f = &t->tree[j];
+
+ /*
+ * n = (f->mantissa > bfloat_mantissa())
+ * ? j * 2
+ * : j * 2 + 1;
+ *
+ * We need to subtract 1 from f->mantissa for the sign bit trick
+ * to work - that's done in make_bfloat()
+ */
+ if (likely(f->exponent != 127))
+ n = j * 2 + (((unsigned)
+ (f->mantissa -
+ bfloat_mantissa(search, f))) >> 31);
+ else
+ n = (bkey_cmp(tree_to_bkey(t, j), search) > 0)
+ ? j * 2
+ : j * 2 + 1;
+ } while (n < t->size);
+
+ inorder = to_inorder(j, t);
+
+ /*
+ * n would have been the node we recursed to - the low bit tells us if
+ * we recursed left or recursed right.
+ */
+ if (n & 1) {
+ l = cacheline_to_bkey(t, inorder, f->m);
+
+ if (++inorder != t->size) {
+ f = &t->tree[inorder_next(j, t->size)];
+ r = cacheline_to_bkey(t, inorder, f->m);
+ } else
+ r = end(t->data);
+ } else {
+ r = cacheline_to_bkey(t, inorder, f->m);
+
+ if (--inorder) {
+ f = &t->tree[inorder_prev(j, t->size)];
+ l = cacheline_to_bkey(t, inorder, f->m);
+ } else
+ l = t->data->start;
+ }
+
+ return (struct bset_search_iter) {l, r};
+}
+
+struct bkey *__bch_bset_search(struct btree *b, struct bset_tree *t,
+ const struct bkey *search)
+{
+ struct bset_search_iter i;
+
+ /*
+ * First, we search for a cacheline, then lastly we do a linear search
+ * within that cacheline.
+ *
+ * To search for the cacheline, there's three different possibilities:
+ * * The set is too small to have a search tree, so we just do a linear
+ * search over the whole set.
+ * * The set is the one we're currently inserting into; keeping a full
+ * auxiliary search tree up to date would be too expensive, so we
+ * use a much simpler lookup table to do a binary search -
+ * bset_search_write_set().
+ * * Or we use the auxiliary search tree we constructed earlier -
+ * bset_search_tree()
+ */
+
+ if (unlikely(!t->size)) {
+ i.l = t->data->start;
+ i.r = end(t->data);
+ } else if (bset_written(b, t)) {
+ /*
+ * Each node in the auxiliary search tree covers a certain range
+ * of bits, and keys above and below the set it covers might
+ * differ outside those bits - so we have to special case the
+ * start and end - handle that here:
+ */
+
+ if (unlikely(bkey_cmp(search, &t->end) >= 0))
+ return end(t->data);
+
+ if (unlikely(bkey_cmp(search, t->data->start) < 0))
+ return t->data->start;
+
+ i = bset_search_tree(b, t, search);
+ } else
+ i = bset_search_write_set(b, t, search);
+
+#ifdef CONFIG_BCACHE_EDEBUG
+ BUG_ON(bset_written(b, t) &&
+ i.l != t->data->start &&
+ bkey_cmp(tree_to_prev_bkey(t,
+ inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
+ search) > 0);
+
+ BUG_ON(i.r != end(t->data) &&
+ bkey_cmp(i.r, search) <= 0);
+#endif
+
+ while (likely(i.l != i.r) &&
+ bkey_cmp(i.l, search) <= 0)
+ i.l = bkey_next(i.l);
+
+ return i.l;
+}
+
+/* Btree iterator */
+
+static inline bool btree_iter_cmp(struct btree_iter_set l,
+ struct btree_iter_set r)
+{
+ int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
+
+ return c ? c > 0 : l.k < r.k;
+}
+
+static inline bool btree_iter_end(struct btree_iter *iter)
+{
+ return !iter->used;
+}
+
+void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
+ struct bkey *end)
+{
+ if (k != end)
+ BUG_ON(!heap_add(iter,
+ ((struct btree_iter_set) { k, end }),
+ btree_iter_cmp));
+}
+
+struct bkey *__bch_btree_iter_init(struct btree *b, struct btree_iter *iter,
+ struct bkey *search, struct bset_tree *start)
+{
+ struct bkey *ret = NULL;
+ iter->size = ARRAY_SIZE(iter->data);
+ iter->used = 0;
+
+ for (; start <= &b->sets[b->nsets]; start++) {
+ ret = bch_bset_search(b, start, search);
+ bch_btree_iter_push(iter, ret, end(start->data));
+ }
+
+ return ret;
+}
+
+struct bkey *bch_btree_iter_next(struct btree_iter *iter)
+{
+ struct btree_iter_set unused;
+ struct bkey *ret = NULL;
+
+ if (!btree_iter_end(iter)) {
+ ret = iter->data->k;
+ iter->data->k = bkey_next(iter->data->k);
+
+ if (iter->data->k > iter->data->end) {
+ __WARN();
+ iter->data->k = iter->data->end;
+ }
+
+ if (iter->data->k == iter->data->end)
+ heap_pop(iter, unused, btree_iter_cmp);
+ else
+ heap_sift(iter, 0, btree_iter_cmp);
+ }
+
+ return ret;
+}
+
+struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
+ struct btree *b, ptr_filter_fn fn)
+{
+ struct bkey *ret;
+
+ do {
+ ret = bch_btree_iter_next(iter);
+ } while (ret && fn(b, ret));
+
+ return ret;
+}
+
+struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search)
+{
+ struct btree_iter iter;
+
+ bch_btree_iter_init(b, &iter, search);
+ return bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
+}
+
+/* Mergesort */
+
+static void btree_sort_fixup(struct btree_iter *iter)
+{
+ while (iter->used > 1) {
+ struct btree_iter_set *top = iter->data, *i = top + 1;
+ struct bkey *k;
+
+ if (iter->used > 2 &&
+ btree_iter_cmp(i[0], i[1]))
+ i++;
+
+ for (k = i->k;
+ k != i->end && bkey_cmp(top->k, &START_KEY(k)) > 0;
+ k = bkey_next(k))
+ if (top->k > i->k)
+ __bch_cut_front(top->k, k);
+ else if (KEY_SIZE(k))
+ bch_cut_back(&START_KEY(k), top->k);
+
+ if (top->k < i->k || k == i->k)
+ break;
+
+ heap_sift(iter, i - top, btree_iter_cmp);
+ }
+}
+
+static void btree_mergesort(struct btree *b, struct bset *out,
+ struct btree_iter *iter,
+ bool fixup, bool remove_stale)
+{
+ struct bkey *k, *last = NULL;
+ bool (*bad)(struct btree *, const struct bkey *) = remove_stale
+ ? bch_ptr_bad
+ : bch_ptr_invalid;
+
+ while (!btree_iter_end(iter)) {
+ if (fixup && !b->level)
+ btree_sort_fixup(iter);
+
+ k = bch_btree_iter_next(iter);
+ if (bad(b, k))
+ continue;
+
+ if (!last) {
+ last = out->start;
+ bkey_copy(last, k);
+ } else if (b->level ||
+ !bch_bkey_try_merge(b, last, k)) {
+ last = bkey_next(last);
+ bkey_copy(last, k);
+ }
+ }
+
+ out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
+
+ pr_debug("sorted %i keys", out->keys);
+ bch_check_key_order(b, out);
+}
+
+static void __btree_sort(struct btree *b, struct btree_iter *iter,
+ unsigned start, unsigned order, bool fixup)
+{
+ uint64_t start_time;
+ bool remove_stale = !b->written;
+ struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOIO,
+ order);
+ if (!out) {
+ mutex_lock(&b->c->sort_lock);
+ out = b->c->sort;
+ order = ilog2(bucket_pages(b->c));
+ }
+
+ start_time = local_clock();
+
+ btree_mergesort(b, out, iter, fixup, remove_stale);
+ b->nsets = start;
+
+ if (!fixup && !start && b->written)
+ bch_btree_verify(b, out);
+
+ if (!start && order == b->page_order) {
+ /*
+ * Our temporary buffer is the same size as the btree node's
+ * buffer, we can just swap buffers instead of doing a big
+ * memcpy()
+ */
+
+ out->magic = bset_magic(b->c);
+ out->seq = b->sets[0].data->seq;
+ out->version = b->sets[0].data->version;
+ swap(out, b->sets[0].data);
+
+ if (b->c->sort == b->sets[0].data)
+ b->c->sort = out;
+ } else {
+ b->sets[start].data->keys = out->keys;
+ memcpy(b->sets[start].data->start, out->start,
+ (void *) end(out) - (void *) out->start);
+ }
+
+ if (out == b->c->sort)
+ mutex_unlock(&b->c->sort_lock);
+ else
+ free_pages((unsigned long) out, order);
+
+ if (b->written)
+ bset_build_written_tree(b);
+
+ if (!start) {
+ spin_lock(&b->c->sort_time_lock);
+ time_stats_update(&b->c->sort_time, start_time);
+ spin_unlock(&b->c->sort_time_lock);
+ }
+}
+
+void bch_btree_sort_partial(struct btree *b, unsigned start)
+{
+ size_t oldsize = 0, order = b->page_order, keys = 0;
+ struct btree_iter iter;
+ __bch_btree_iter_init(b, &iter, NULL, &b->sets[start]);
+
+ BUG_ON(b->sets[b->nsets].data == write_block(b) &&
+ (b->sets[b->nsets].size || b->nsets));
+
+ if (b->written)
+ oldsize = bch_count_data(b);
+
+ if (start) {
+ unsigned i;
+
+ for (i = start; i <= b->nsets; i++)
+ keys += b->sets[i].data->keys;
+
+ order = roundup_pow_of_two(__set_bytes(b->sets->data, keys)) / PAGE_SIZE;
+ if (order)
+ order = ilog2(order);
+ }
+
+ __btree_sort(b, &iter, start, order, false);
+
+ EBUG_ON(b->written && bch_count_data(b) != oldsize);
+}
+
+void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter)
+{
+ BUG_ON(!b->written);
+ __btree_sort(b, iter, 0, b->page_order, true);
+}
+
+void bch_btree_sort_into(struct btree *b, struct btree *new)
+{
+ uint64_t start_time = local_clock();
+
+ struct btree_iter iter;
+ bch_btree_iter_init(b, &iter, NULL);
+
+ btree_mergesort(b, new->sets->data, &iter, false, true);
+
+ spin_lock(&b->c->sort_time_lock);
+ time_stats_update(&b->c->sort_time, start_time);
+ spin_unlock(&b->c->sort_time_lock);
+
+ bkey_copy_key(&new->key, &b->key);
+ new->sets->size = 0;
+}
+
+void bch_btree_sort_lazy(struct btree *b)
+{
+ if (b->nsets) {
+ unsigned i, j, keys = 0, total;
+
+ for (i = 0; i <= b->nsets; i++)
+ keys += b->sets[i].data->keys;
+
+ total = keys;
+
+ for (j = 0; j < b->nsets; j++) {
+ if (keys * 2 < total ||
+ keys < 1000) {
+ bch_btree_sort_partial(b, j);
+ return;
+ }
+
+ keys -= b->sets[j].data->keys;
+ }
+
+ /* Must sort if b->nsets == 3 or we'll overflow */
+ if (b->nsets >= (MAX_BSETS - 1) - b->level) {
+ bch_btree_sort(b);
+ return;
+ }
+ }
+
+ bset_build_written_tree(b);
+}
+
+/* Sysfs stuff */
+
+struct bset_stats {
+ size_t nodes;
+ size_t sets_written, sets_unwritten;
+ size_t bytes_written, bytes_unwritten;
+ size_t floats, failed;
+};
+
+static int bch_btree_bset_stats(struct btree *b, struct btree_op *op,
+ struct bset_stats *stats)
+{
+ struct bkey *k;
+ unsigned i;
+
+ stats->nodes++;
+
+ for (i = 0; i <= b->nsets; i++) {
+ struct bset_tree *t = &b->sets[i];
+ size_t bytes = t->data->keys * sizeof(uint64_t);
+ size_t j;
+
+ if (bset_written(b, t)) {
+ stats->sets_written++;
+ stats->bytes_written += bytes;
+
+ stats->floats += t->size - 1;
+
+ for (j = 1; j < t->size; j++)
+ if (t->tree[j].exponent == 127)
+ stats->failed++;
+ } else {
+ stats->sets_unwritten++;
+ stats->bytes_unwritten += bytes;
+ }
+ }
+
+ if (b->level) {
+ struct btree_iter iter;
+
+ for_each_key_filter(b, k, &iter, bch_ptr_bad) {
+ int ret = btree(bset_stats, k, b, op, stats);
+ if (ret)
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+int bch_bset_print_stats(struct cache_set *c, char *buf)
+{
+ struct btree_op op;
+ struct bset_stats t;
+ int ret;
+
+ bch_btree_op_init_stack(&op);
+ memset(&t, 0, sizeof(struct bset_stats));
+
+ ret = btree_root(bset_stats, c, &op, &t);
+ if (ret)
+ return ret;
+
+ return snprintf(buf, PAGE_SIZE,
+ "btree nodes: %zu\n"
+ "written sets: %zu\n"
+ "unwritten sets: %zu\n"
+ "written key bytes: %zu\n"
+ "unwritten key bytes: %zu\n"
+ "floats: %zu\n"
+ "failed: %zu\n",
+ t.nodes,
+ t.sets_written, t.sets_unwritten,
+ t.bytes_written, t.bytes_unwritten,
+ t.floats, t.failed);
+}
--- /dev/null
+#ifndef _BCACHE_BSET_H
+#define _BCACHE_BSET_H
+
+/*
+ * BKEYS:
+ *
+ * A bkey contains a key, a size field, a variable number of pointers, and some
+ * ancillary flag bits.
+ *
+ * We use two different functions for validating bkeys, bch_ptr_invalid and
+ * bch_ptr_bad().
+ *
+ * bch_ptr_invalid() primarily filters out keys and pointers that would be
+ * invalid due to some sort of bug, whereas bch_ptr_bad() filters out keys and
+ * pointer that occur in normal practice but don't point to real data.
+ *
+ * The one exception to the rule that ptr_invalid() filters out invalid keys is
+ * that it also filters out keys of size 0 - these are keys that have been
+ * completely overwritten. It'd be safe to delete these in memory while leaving
+ * them on disk, just unnecessary work - so we filter them out when resorting
+ * instead.
+ *
+ * We can't filter out stale keys when we're resorting, because garbage
+ * collection needs to find them to ensure bucket gens don't wrap around -
+ * unless we're rewriting the btree node those stale keys still exist on disk.
+ *
+ * We also implement functions here for removing some number of sectors from the
+ * front or the back of a bkey - this is mainly used for fixing overlapping
+ * extents, by removing the overlapping sectors from the older key.
+ *
+ * BSETS:
+ *
+ * A bset is an array of bkeys laid out contiguously in memory in sorted order,
+ * along with a header. A btree node is made up of a number of these, written at
+ * different times.
+ *
+ * There could be many of them on disk, but we never allow there to be more than
+ * 4 in memory - we lazily resort as needed.
+ *
+ * We implement code here for creating and maintaining auxiliary search trees
+ * (described below) for searching an individial bset, and on top of that we
+ * implement a btree iterator.
+ *
+ * BTREE ITERATOR:
+ *
+ * Most of the code in bcache doesn't care about an individual bset - it needs
+ * to search entire btree nodes and iterate over them in sorted order.
+ *
+ * The btree iterator code serves both functions; it iterates through the keys
+ * in a btree node in sorted order, starting from either keys after a specific
+ * point (if you pass it a search key) or the start of the btree node.
+ *
+ * AUXILIARY SEARCH TREES:
+ *
+ * Since keys are variable length, we can't use a binary search on a bset - we
+ * wouldn't be able to find the start of the next key. But binary searches are
+ * slow anyways, due to terrible cache behaviour; bcache originally used binary
+ * searches and that code topped out at under 50k lookups/second.
+ *
+ * So we need to construct some sort of lookup table. Since we only insert keys
+ * into the last (unwritten) set, most of the keys within a given btree node are
+ * usually in sets that are mostly constant. We use two different types of
+ * lookup tables to take advantage of this.
+ *
+ * Both lookup tables share in common that they don't index every key in the
+ * set; they index one key every BSET_CACHELINE bytes, and then a linear search
+ * is used for the rest.
+ *
+ * For sets that have been written to disk and are no longer being inserted
+ * into, we construct a binary search tree in an array - traversing a binary
+ * search tree in an array gives excellent locality of reference and is very
+ * fast, since both children of any node are adjacent to each other in memory
+ * (and their grandchildren, and great grandchildren...) - this means
+ * prefetching can be used to great effect.
+ *
+ * It's quite useful performance wise to keep these nodes small - not just
+ * because they're more likely to be in L2, but also because we can prefetch
+ * more nodes on a single cacheline and thus prefetch more iterations in advance
+ * when traversing this tree.
+ *
+ * Nodes in the auxiliary search tree must contain both a key to compare against
+ * (we don't want to fetch the key from the set, that would defeat the purpose),
+ * and a pointer to the key. We use a few tricks to compress both of these.
+ *
+ * To compress the pointer, we take advantage of the fact that one node in the
+ * search tree corresponds to precisely BSET_CACHELINE bytes in the set. We have
+ * a function (to_inorder()) that takes the index of a node in a binary tree and
+ * returns what its index would be in an inorder traversal, so we only have to
+ * store the low bits of the offset.
+ *
+ * The key is 84 bits (KEY_DEV + key->key, the offset on the device). To
+ * compress that, we take advantage of the fact that when we're traversing the
+ * search tree at every iteration we know that both our search key and the key
+ * we're looking for lie within some range - bounded by our previous
+ * comparisons. (We special case the start of a search so that this is true even
+ * at the root of the tree).
+ *
+ * So we know the key we're looking for is between a and b, and a and b don't
+ * differ higher than bit 50, we don't need to check anything higher than bit
+ * 50.
+ *
+ * We don't usually need the rest of the bits, either; we only need enough bits
+ * to partition the key range we're currently checking. Consider key n - the
+ * key our auxiliary search tree node corresponds to, and key p, the key
+ * immediately preceding n. The lowest bit we need to store in the auxiliary
+ * search tree is the highest bit that differs between n and p.
+ *
+ * Note that this could be bit 0 - we might sometimes need all 80 bits to do the
+ * comparison. But we'd really like our nodes in the auxiliary search tree to be
+ * of fixed size.
+ *
+ * The solution is to make them fixed size, and when we're constructing a node
+ * check if p and n differed in the bits we needed them to. If they don't we
+ * flag that node, and when doing lookups we fallback to comparing against the
+ * real key. As long as this doesn't happen to often (and it seems to reliably
+ * happen a bit less than 1% of the time), we win - even on failures, that key
+ * is then more likely to be in cache than if we were doing binary searches all
+ * the way, since we're touching so much less memory.
+ *
+ * The keys in the auxiliary search tree are stored in (software) floating
+ * point, with an exponent and a mantissa. The exponent needs to be big enough
+ * to address all the bits in the original key, but the number of bits in the
+ * mantissa is somewhat arbitrary; more bits just gets us fewer failures.
+ *
+ * We need 7 bits for the exponent and 3 bits for the key's offset (since keys
+ * are 8 byte aligned); using 22 bits for the mantissa means a node is 4 bytes.
+ * We need one node per 128 bytes in the btree node, which means the auxiliary
+ * search trees take up 3% as much memory as the btree itself.
+ *
+ * Constructing these auxiliary search trees is moderately expensive, and we
+ * don't want to be constantly rebuilding the search tree for the last set
+ * whenever we insert another key into it. For the unwritten set, we use a much
+ * simpler lookup table - it's just a flat array, so index i in the lookup table
+ * corresponds to the i range of BSET_CACHELINE bytes in the set. Indexing
+ * within each byte range works the same as with the auxiliary search trees.
+ *
+ * These are much easier to keep up to date when we insert a key - we do it
+ * somewhat lazily; when we shift a key up we usually just increment the pointer
+ * to it, only when it would overflow do we go to the trouble of finding the
+ * first key in that range of bytes again.
+ */
+
+/* Btree key comparison/iteration */
+
+struct btree_iter {
+ size_t size, used;
+ struct btree_iter_set {
+ struct bkey *k, *end;
+ } data[MAX_BSETS];
+};
+
+struct bset_tree {
+ /*
+ * We construct a binary tree in an array as if the array
+ * started at 1, so that things line up on the same cachelines
+ * better: see comments in bset.c at cacheline_to_bkey() for
+ * details
+ */
+
+ /* size of the binary tree and prev array */
+ unsigned size;
+
+ /* function of size - precalculated for to_inorder() */
+ unsigned extra;
+
+ /* copy of the last key in the set */
+ struct bkey end;
+ struct bkey_float *tree;
+
+ /*
+ * The nodes in the bset tree point to specific keys - this
+ * array holds the sizes of the previous key.
+ *
+ * Conceptually it's a member of struct bkey_float, but we want
+ * to keep bkey_float to 4 bytes and prev isn't used in the fast
+ * path.
+ */
+ uint8_t *prev;
+
+ /* The actual btree node, with pointers to each sorted set */
+ struct bset *data;
+};
+
+static __always_inline int64_t bkey_cmp(const struct bkey *l,
+ const struct bkey *r)
+{
+ return unlikely(KEY_INODE(l) != KEY_INODE(r))
+ ? (int64_t) KEY_INODE(l) - (int64_t) KEY_INODE(r)
+ : (int64_t) KEY_OFFSET(l) - (int64_t) KEY_OFFSET(r);
+}
+
+static inline size_t bkey_u64s(const struct bkey *k)
+{
+ BUG_ON(KEY_CSUM(k) > 1);
+ return 2 + KEY_PTRS(k) + (KEY_CSUM(k) ? 1 : 0);
+}
+
+static inline size_t bkey_bytes(const struct bkey *k)
+{
+ return bkey_u64s(k) * sizeof(uint64_t);
+}
+
+static inline void bkey_copy(struct bkey *dest, const struct bkey *src)
+{
+ memcpy(dest, src, bkey_bytes(src));
+}
+
+static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
+{
+ if (!src)
+ src = &KEY(0, 0, 0);
+
+ SET_KEY_INODE(dest, KEY_INODE(src));
+ SET_KEY_OFFSET(dest, KEY_OFFSET(src));
+}
+
+static inline struct bkey *bkey_next(const struct bkey *k)
+{
+ uint64_t *d = (void *) k;
+ return (struct bkey *) (d + bkey_u64s(k));
+}
+
+/* Keylists */
+
+struct keylist {
+ struct bkey *top;
+ union {
+ uint64_t *list;
+ struct bkey *bottom;
+ };
+
+ /* Enough room for btree_split's keys without realloc */
+#define KEYLIST_INLINE 16
+ uint64_t d[KEYLIST_INLINE];
+};
+
+static inline void bch_keylist_init(struct keylist *l)
+{
+ l->top = (void *) (l->list = l->d);
+}
+
+static inline void bch_keylist_push(struct keylist *l)
+{
+ l->top = bkey_next(l->top);
+}
+
+static inline void bch_keylist_add(struct keylist *l, struct bkey *k)
+{
+ bkey_copy(l->top, k);
+ bch_keylist_push(l);
+}
+
+static inline bool bch_keylist_empty(struct keylist *l)
+{
+ return l->top == (void *) l->list;
+}
+
+static inline void bch_keylist_free(struct keylist *l)
+{
+ if (l->list != l->d)
+ kfree(l->list);
+}
+
+void bch_keylist_copy(struct keylist *, struct keylist *);
+struct bkey *bch_keylist_pop(struct keylist *);
+int bch_keylist_realloc(struct keylist *, int, struct cache_set *);
+
+void bch_bkey_copy_single_ptr(struct bkey *, const struct bkey *,
+ unsigned);
+bool __bch_cut_front(const struct bkey *, struct bkey *);
+bool __bch_cut_back(const struct bkey *, struct bkey *);
+
+static inline bool bch_cut_front(const struct bkey *where, struct bkey *k)
+{
+ BUG_ON(bkey_cmp(where, k) > 0);
+ return __bch_cut_front(where, k);
+}
+
+static inline bool bch_cut_back(const struct bkey *where, struct bkey *k)
+{
+ BUG_ON(bkey_cmp(where, &START_KEY(k)) < 0);
+ return __bch_cut_back(where, k);
+}
+
+const char *bch_ptr_status(struct cache_set *, const struct bkey *);
+bool __bch_ptr_invalid(struct cache_set *, int level, const struct bkey *);
+bool bch_ptr_bad(struct btree *, const struct bkey *);
+
+static inline uint8_t gen_after(uint8_t a, uint8_t b)
+{
+ uint8_t r = a - b;
+ return r > 128U ? 0 : r;
+}
+
+static inline uint8_t ptr_stale(struct cache_set *c, const struct bkey *k,
+ unsigned i)
+{
+ return gen_after(PTR_BUCKET(c, k, i)->gen, PTR_GEN(k, i));
+}
+
+static inline bool ptr_available(struct cache_set *c, const struct bkey *k,
+ unsigned i)
+{
+ return (PTR_DEV(k, i) < MAX_CACHES_PER_SET) && PTR_CACHE(c, k, i);
+}
+
+
+typedef bool (*ptr_filter_fn)(struct btree *, const struct bkey *);
+
+struct bkey *bch_next_recurse_key(struct btree *, struct bkey *);
+struct bkey *bch_btree_iter_next(struct btree_iter *);
+struct bkey *bch_btree_iter_next_filter(struct btree_iter *,
+ struct btree *, ptr_filter_fn);
+
+void bch_btree_iter_push(struct btree_iter *, struct bkey *, struct bkey *);
+struct bkey *__bch_btree_iter_init(struct btree *, struct btree_iter *,
+ struct bkey *, struct bset_tree *);
+
+/* 32 bits total: */
+#define BKEY_MID_BITS 3
+#define BKEY_EXPONENT_BITS 7
+#define BKEY_MANTISSA_BITS 22
+#define BKEY_MANTISSA_MASK ((1 << BKEY_MANTISSA_BITS) - 1)
+
+struct bkey_float {
+ unsigned exponent:BKEY_EXPONENT_BITS;
+ unsigned m:BKEY_MID_BITS;
+ unsigned mantissa:BKEY_MANTISSA_BITS;
+} __packed;
+
+/*
+ * BSET_CACHELINE was originally intended to match the hardware cacheline size -
+ * it used to be 64, but I realized the lookup code would touch slightly less
+ * memory if it was 128.
+ *
+ * It definites the number of bytes (in struct bset) per struct bkey_float in
+ * the auxiliar search tree - when we're done searching the bset_float tree we
+ * have this many bytes left that we do a linear search over.
+ *
+ * Since (after level 5) every level of the bset_tree is on a new cacheline,
+ * we're touching one fewer cacheline in the bset tree in exchange for one more
+ * cacheline in the linear search - but the linear search might stop before it
+ * gets to the second cacheline.
+ */
+
+#define BSET_CACHELINE 128
+#define bset_tree_space(b) (btree_data_space(b) / BSET_CACHELINE)
+
+#define bset_tree_bytes(b) (bset_tree_space(b) * sizeof(struct bkey_float))
+#define bset_prev_bytes(b) (bset_tree_space(b) * sizeof(uint8_t))
+
+void bch_bset_init_next(struct btree *);
+
+void bch_bset_fix_invalidated_key(struct btree *, struct bkey *);
+void bch_bset_fix_lookup_table(struct btree *, struct bkey *);
+
+struct bkey *__bch_bset_search(struct btree *, struct bset_tree *,
+ const struct bkey *);
+
+static inline struct bkey *bch_bset_search(struct btree *b, struct bset_tree *t,
+ const struct bkey *search)
+{
+ return search ? __bch_bset_search(b, t, search) : t->data->start;
+}
+
+bool bch_bkey_try_merge(struct btree *, struct bkey *, struct bkey *);
+void bch_btree_sort_lazy(struct btree *);
+void bch_btree_sort_into(struct btree *, struct btree *);
+void bch_btree_sort_and_fix_extents(struct btree *, struct btree_iter *);
+void bch_btree_sort_partial(struct btree *, unsigned);
+
+static inline void bch_btree_sort(struct btree *b)
+{
+ bch_btree_sort_partial(b, 0);
+}
+
+int bch_bset_print_stats(struct cache_set *, char *);
+
+#endif
--- /dev/null
+/*
+ * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
+ *
+ * Uses a block device as cache for other block devices; optimized for SSDs.
+ * All allocation is done in buckets, which should match the erase block size
+ * of the device.
+ *
+ * Buckets containing cached data are kept on a heap sorted by priority;
+ * bucket priority is increased on cache hit, and periodically all the buckets
+ * on the heap have their priority scaled down. This currently is just used as
+ * an LRU but in the future should allow for more intelligent heuristics.
+ *
+ * Buckets have an 8 bit counter; freeing is accomplished by incrementing the
+ * counter. Garbage collection is used to remove stale pointers.
+ *
+ * Indexing is done via a btree; nodes are not necessarily fully sorted, rather
+ * as keys are inserted we only sort the pages that have not yet been written.
+ * When garbage collection is run, we resort the entire node.
+ *
+ * All configuration is done via sysfs; see Documentation/bcache.txt.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+#include <linux/slab.h>
+#include <linux/bitops.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include <linux/rcupdate.h>
+#include <trace/events/bcache.h>
+
+/*
+ * Todo:
+ * register_bcache: Return errors out to userspace correctly
+ *
+ * Writeback: don't undirty key until after a cache flush
+ *
+ * Create an iterator for key pointers
+ *
+ * On btree write error, mark bucket such that it won't be freed from the cache
+ *
+ * Journalling:
+ * Check for bad keys in replay
+ * Propagate barriers
+ * Refcount journal entries in journal_replay
+ *
+ * Garbage collection:
+ * Finish incremental gc
+ * Gc should free old UUIDs, data for invalid UUIDs
+ *
+ * Provide a way to list backing device UUIDs we have data cached for, and
+ * probably how long it's been since we've seen them, and a way to invalidate
+ * dirty data for devices that will never be attached again
+ *
+ * Keep 1 min/5 min/15 min statistics of how busy a block device has been, so
+ * that based on that and how much dirty data we have we can keep writeback
+ * from being starved
+ *
+ * Add a tracepoint or somesuch to watch for writeback starvation
+ *
+ * When btree depth > 1 and splitting an interior node, we have to make sure
+ * alloc_bucket() cannot fail. This should be true but is not completely
+ * obvious.
+ *
+ * Make sure all allocations get charged to the root cgroup
+ *
+ * Plugging?
+ *
+ * If data write is less than hard sector size of ssd, round up offset in open
+ * bucket to the next whole sector
+ *
+ * Also lookup by cgroup in get_open_bucket()
+ *
+ * Superblock needs to be fleshed out for multiple cache devices
+ *
+ * Add a sysfs tunable for the number of writeback IOs in flight
+ *
+ * Add a sysfs tunable for the number of open data buckets
+ *
+ * IO tracking: Can we track when one process is doing io on behalf of another?
+ * IO tracking: Don't use just an average, weigh more recent stuff higher
+ *
+ * Test module load/unload
+ */
+
+static const char * const op_types[] = {
+ "insert", "replace"
+};
+
+static const char *op_type(struct btree_op *op)
+{
+ return op_types[op->type];
+}
+
+#define MAX_NEED_GC 64
+#define MAX_SAVE_PRIO 72
+
+#define PTR_DIRTY_BIT (((uint64_t) 1 << 36))
+
+#define PTR_HASH(c, k) \
+ (((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0))
+
+struct workqueue_struct *bch_gc_wq;
+static struct workqueue_struct *btree_io_wq;
+
+void bch_btree_op_init_stack(struct btree_op *op)
+{
+ memset(op, 0, sizeof(struct btree_op));
+ closure_init_stack(&op->cl);
+ op->lock = -1;
+ bch_keylist_init(&op->keys);
+}
+
+/* Btree key manipulation */
+
+static void bkey_put(struct cache_set *c, struct bkey *k, int level)
+{
+ if ((level && KEY_OFFSET(k)) || !level)
+ __bkey_put(c, k);
+}
+
+/* Btree IO */
+
+static uint64_t btree_csum_set(struct btree *b, struct bset *i)
+{
+ uint64_t crc = b->key.ptr[0];
+ void *data = (void *) i + 8, *end = end(i);
+
+ crc = crc64_update(crc, data, end - data);
+ return crc ^ 0xffffffffffffffff;
+}
+
+static void btree_bio_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+ struct btree *b = container_of(cl, struct btree, io.cl);
+
+ if (error)
+ set_btree_node_io_error(b);
+
+ bch_bbio_count_io_errors(b->c, bio, error, (bio->bi_rw & WRITE)
+ ? "writing btree" : "reading btree");
+ closure_put(cl);
+}
+
+static void btree_bio_init(struct btree *b)
+{
+ BUG_ON(b->bio);
+ b->bio = bch_bbio_alloc(b->c);
+
+ b->bio->bi_end_io = btree_bio_endio;
+ b->bio->bi_private = &b->io.cl;
+}
+
+void bch_btree_read_done(struct closure *cl)
+{
+ struct btree *b = container_of(cl, struct btree, io.cl);
+ struct bset *i = b->sets[0].data;
+ struct btree_iter *iter = b->c->fill_iter;
+ const char *err = "bad btree header";
+ BUG_ON(b->nsets || b->written);
+
+ bch_bbio_free(b->bio, b->c);
+ b->bio = NULL;
+
+ mutex_lock(&b->c->fill_lock);
+ iter->used = 0;
+
+ if (btree_node_io_error(b) ||
+ !i->seq)
+ goto err;
+
+ for (;
+ b->written < btree_blocks(b) && i->seq == b->sets[0].data->seq;
+ i = write_block(b)) {
+ err = "unsupported bset version";
+ if (i->version > BCACHE_BSET_VERSION)
+ goto err;
+
+ err = "bad btree header";
+ if (b->written + set_blocks(i, b->c) > btree_blocks(b))
+ goto err;
+
+ err = "bad magic";
+ if (i->magic != bset_magic(b->c))
+ goto err;
+
+ err = "bad checksum";
+ switch (i->version) {
+ case 0:
+ if (i->csum != csum_set(i))
+ goto err;
+ break;
+ case BCACHE_BSET_VERSION:
+ if (i->csum != btree_csum_set(b, i))
+ goto err;
+ break;
+ }
+
+ err = "empty set";
+ if (i != b->sets[0].data && !i->keys)
+ goto err;
+
+ bch_btree_iter_push(iter, i->start, end(i));
+
+ b->written += set_blocks(i, b->c);
+ }
+
+ err = "corrupted btree";
+ for (i = write_block(b);
+ index(i, b) < btree_blocks(b);
+ i = ((void *) i) + block_bytes(b->c))
+ if (i->seq == b->sets[0].data->seq)
+ goto err;
+
+ bch_btree_sort_and_fix_extents(b, iter);
+
+ i = b->sets[0].data;
+ err = "short btree key";
+ if (b->sets[0].size &&
+ bkey_cmp(&b->key, &b->sets[0].end) < 0)
+ goto err;
+
+ if (b->written < btree_blocks(b))
+ bch_bset_init_next(b);
+out:
+
+ mutex_unlock(&b->c->fill_lock);
+
+ spin_lock(&b->c->btree_read_time_lock);
+ time_stats_update(&b->c->btree_read_time, b->io_start_time);
+ spin_unlock(&b->c->btree_read_time_lock);
+
+ smp_wmb(); /* read_done is our write lock */
+ set_btree_node_read_done(b);
+
+ closure_return(cl);
+err:
+ set_btree_node_io_error(b);
+ bch_cache_set_error(b->c, "%s at bucket %lu, block %zu, %u keys",
+ err, PTR_BUCKET_NR(b->c, &b->key, 0),
+ index(i, b), i->keys);
+ goto out;
+}
+
+void bch_btree_read(struct btree *b)
+{
+ BUG_ON(b->nsets || b->written);
+
+ if (!closure_trylock(&b->io.cl, &b->c->cl))
+ BUG();
+
+ b->io_start_time = local_clock();
+
+ btree_bio_init(b);
+ b->bio->bi_rw = REQ_META|READ_SYNC;
+ b->bio->bi_size = KEY_SIZE(&b->key) << 9;
+
+ bio_map(b->bio, b->sets[0].data);
+
+ pr_debug("%s", pbtree(b));
+ trace_bcache_btree_read(b->bio);
+ bch_submit_bbio(b->bio, b->c, &b->key, 0);
+
+ continue_at(&b->io.cl, bch_btree_read_done, system_wq);
+}
+
+static void btree_complete_write(struct btree *b, struct btree_write *w)
+{
+ if (w->prio_blocked &&
+ !atomic_sub_return(w->prio_blocked, &b->c->prio_blocked))
+ wake_up(&b->c->alloc_wait);
+
+ if (w->journal) {
+ atomic_dec_bug(w->journal);
+ __closure_wake_up(&b->c->journal.wait);
+ }
+
+ if (w->owner)
+ closure_put(w->owner);
+
+ w->prio_blocked = 0;
+ w->journal = NULL;
+ w->owner = NULL;
+}
+
+static void __btree_write_done(struct closure *cl)
+{
+ struct btree *b = container_of(cl, struct btree, io.cl);
+ struct btree_write *w = btree_prev_write(b);
+
+ bch_bbio_free(b->bio, b->c);
+ b->bio = NULL;
+ btree_complete_write(b, w);
+
+ if (btree_node_dirty(b))
+ queue_delayed_work(btree_io_wq, &b->work,
+ msecs_to_jiffies(30000));
+
+ closure_return(cl);
+}
+
+static void btree_write_done(struct closure *cl)
+{
+ struct btree *b = container_of(cl, struct btree, io.cl);
+ struct bio_vec *bv;
+ int n;
+
+ __bio_for_each_segment(bv, b->bio, n, 0)
+ __free_page(bv->bv_page);
+
+ __btree_write_done(cl);
+}
+
+static void do_btree_write(struct btree *b)
+{
+ struct closure *cl = &b->io.cl;
+ struct bset *i = b->sets[b->nsets].data;
+ BKEY_PADDED(key) k;
+
+ i->version = BCACHE_BSET_VERSION;
+ i->csum = btree_csum_set(b, i);
+
+ btree_bio_init(b);
+ b->bio->bi_rw = REQ_META|WRITE_SYNC;
+ b->bio->bi_size = set_blocks(i, b->c) * block_bytes(b->c);
+ bio_map(b->bio, i);
+
+ bkey_copy(&k.key, &b->key);
+ SET_PTR_OFFSET(&k.key, 0, PTR_OFFSET(&k.key, 0) + bset_offset(b, i));
+
+ if (!bio_alloc_pages(b->bio, GFP_NOIO)) {
+ int j;
+ struct bio_vec *bv;
+ void *base = (void *) ((unsigned long) i & ~(PAGE_SIZE - 1));
+
+ bio_for_each_segment(bv, b->bio, j)
+ memcpy(page_address(bv->bv_page),
+ base + j * PAGE_SIZE, PAGE_SIZE);
+
+ trace_bcache_btree_write(b->bio);
+ bch_submit_bbio(b->bio, b->c, &k.key, 0);
+
+ continue_at(cl, btree_write_done, NULL);
+ } else {
+ b->bio->bi_vcnt = 0;
+ bio_map(b->bio, i);
+
+ trace_bcache_btree_write(b->bio);
+ bch_submit_bbio(b->bio, b->c, &k.key, 0);
+
+ closure_sync(cl);
+ __btree_write_done(cl);
+ }
+}
+
+static void __btree_write(struct btree *b)
+{
+ struct bset *i = b->sets[b->nsets].data;
+
+ BUG_ON(current->bio_list);
+
+ closure_lock(&b->io, &b->c->cl);
+ cancel_delayed_work(&b->work);
+
+ clear_bit(BTREE_NODE_dirty, &b->flags);
+ change_bit(BTREE_NODE_write_idx, &b->flags);
+
+ bch_check_key_order(b, i);
+ BUG_ON(b->written && !i->keys);
+
+ do_btree_write(b);
+
+ pr_debug("%s block %i keys %i", pbtree(b), b->written, i->keys);
+
+ b->written += set_blocks(i, b->c);
+ atomic_long_add(set_blocks(i, b->c) * b->c->sb.block_size,
+ &PTR_CACHE(b->c, &b->key, 0)->btree_sectors_written);
+
+ bch_btree_sort_lazy(b);
+
+ if (b->written < btree_blocks(b))
+ bch_bset_init_next(b);
+}
+
+static void btree_write_work(struct work_struct *w)
+{
+ struct btree *b = container_of(to_delayed_work(w), struct btree, work);
+
+ down_write(&b->lock);
+
+ if (btree_node_dirty(b))
+ __btree_write(b);
+ up_write(&b->lock);
+}
+
+void bch_btree_write(struct btree *b, bool now, struct btree_op *op)
+{
+ struct bset *i = b->sets[b->nsets].data;
+ struct btree_write *w = btree_current_write(b);
+
+ BUG_ON(b->written &&
+ (b->written >= btree_blocks(b) ||
+ i->seq != b->sets[0].data->seq ||
+ !i->keys));
+
+ if (!btree_node_dirty(b)) {
+ set_btree_node_dirty(b);
+ queue_delayed_work(btree_io_wq, &b->work,
+ msecs_to_jiffies(30000));
+ }
+
+ w->prio_blocked += b->prio_blocked;
+ b->prio_blocked = 0;
+
+ if (op && op->journal && !b->level) {
+ if (w->journal &&
+ journal_pin_cmp(b->c, w, op)) {
+ atomic_dec_bug(w->journal);
+ w->journal = NULL;
+ }
+
+ if (!w->journal) {
+ w->journal = op->journal;
+ atomic_inc(w->journal);
+ }
+ }
+
+ if (current->bio_list)
+ return;
+
+ /* Force write if set is too big */
+ if (now ||
+ b->level ||
+ set_bytes(i) > PAGE_SIZE - 48) {
+ if (op && now) {
+ /* Must wait on multiple writes */
+ BUG_ON(w->owner);
+ w->owner = &op->cl;
+ closure_get(&op->cl);
+ }
+
+ __btree_write(b);
+ }
+ BUG_ON(!b->written);
+}
+
+/*
+ * Btree in memory cache - allocation/freeing
+ * mca -> memory cache
+ */
+
+static void mca_reinit(struct btree *b)
+{
+ unsigned i;
+
+ b->flags = 0;
+ b->written = 0;
+ b->nsets = 0;
+
+ for (i = 0; i < MAX_BSETS; i++)
+ b->sets[i].size = 0;
+ /*
+ * Second loop starts at 1 because b->sets[0]->data is the memory we
+ * allocated
+ */
+ for (i = 1; i < MAX_BSETS; i++)
+ b->sets[i].data = NULL;
+}
+
+#define mca_reserve(c) (((c->root && c->root->level) \
+ ? c->root->level : 1) * 8 + 16)
+#define mca_can_free(c) \
+ max_t(int, 0, c->bucket_cache_used - mca_reserve(c))
+
+static void mca_data_free(struct btree *b)
+{
+ struct bset_tree *t = b->sets;
+ BUG_ON(!closure_is_unlocked(&b->io.cl));
+
+ if (bset_prev_bytes(b) < PAGE_SIZE)
+ kfree(t->prev);
+ else
+ free_pages((unsigned long) t->prev,
+ get_order(bset_prev_bytes(b)));
+
+ if (bset_tree_bytes(b) < PAGE_SIZE)
+ kfree(t->tree);
+ else
+ free_pages((unsigned long) t->tree,
+ get_order(bset_tree_bytes(b)));
+
+ free_pages((unsigned long) t->data, b->page_order);
+
+ t->prev = NULL;
+ t->tree = NULL;
+ t->data = NULL;
+ list_move(&b->list, &b->c->btree_cache_freed);
+ b->c->bucket_cache_used--;
+}
+
+static void mca_bucket_free(struct btree *b)
+{
+ BUG_ON(btree_node_dirty(b));
+
+ b->key.ptr[0] = 0;
+ hlist_del_init_rcu(&b->hash);
+ list_move(&b->list, &b->c->btree_cache_freeable);
+}
+
+static unsigned btree_order(struct bkey *k)
+{
+ return ilog2(KEY_SIZE(k) / PAGE_SECTORS ?: 1);
+}
+
+static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
+{
+ struct bset_tree *t = b->sets;
+ BUG_ON(t->data);
+
+ b->page_order = max_t(unsigned,
+ ilog2(b->c->btree_pages),
+ btree_order(k));
+
+ t->data = (void *) __get_free_pages(gfp, b->page_order);
+ if (!t->data)
+ goto err;
+
+ t->tree = bset_tree_bytes(b) < PAGE_SIZE
+ ? kmalloc(bset_tree_bytes(b), gfp)
+ : (void *) __get_free_pages(gfp, get_order(bset_tree_bytes(b)));
+ if (!t->tree)
+ goto err;
+
+ t->prev = bset_prev_bytes(b) < PAGE_SIZE
+ ? kmalloc(bset_prev_bytes(b), gfp)
+ : (void *) __get_free_pages(gfp, get_order(bset_prev_bytes(b)));
+ if (!t->prev)
+ goto err;
+
+ list_move(&b->list, &b->c->btree_cache);
+ b->c->bucket_cache_used++;
+ return;
+err:
+ mca_data_free(b);
+}
+
+static struct btree *mca_bucket_alloc(struct cache_set *c,
+ struct bkey *k, gfp_t gfp)
+{
+ struct btree *b = kzalloc(sizeof(struct btree), gfp);
+ if (!b)
+ return NULL;
+
+ init_rwsem(&b->lock);
+ lockdep_set_novalidate_class(&b->lock);
+ INIT_LIST_HEAD(&b->list);
+ INIT_DELAYED_WORK(&b->work, btree_write_work);
+ b->c = c;
+ closure_init_unlocked(&b->io);
+
+ mca_data_alloc(b, k, gfp);
+ return b;
+}
+
+static int mca_reap(struct btree *b, struct closure *cl, unsigned min_order)
+{
+ lockdep_assert_held(&b->c->bucket_lock);
+
+ if (!down_write_trylock(&b->lock))
+ return -ENOMEM;
+
+ if (b->page_order < min_order) {
+ rw_unlock(true, b);
+ return -ENOMEM;
+ }
+
+ BUG_ON(btree_node_dirty(b) && !b->sets[0].data);
+
+ if (cl && btree_node_dirty(b))
+ bch_btree_write(b, true, NULL);
+
+ if (cl)
+ closure_wait_event_async(&b->io.wait, cl,
+ atomic_read(&b->io.cl.remaining) == -1);
+
+ if (btree_node_dirty(b) ||
+ !closure_is_unlocked(&b->io.cl) ||
+ work_pending(&b->work.work)) {
+ rw_unlock(true, b);
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static int bch_mca_shrink(struct shrinker *shrink, struct shrink_control *sc)
+{
+ struct cache_set *c = container_of(shrink, struct cache_set, shrink);
+ struct btree *b, *t;
+ unsigned long i, nr = sc->nr_to_scan;
+
+ if (c->shrinker_disabled)
+ return 0;
+
+ if (c->try_harder)
+ return 0;
+
+ /*
+ * If nr == 0, we're supposed to return the number of items we have
+ * cached. Not allowed to return -1.
+ */
+ if (!nr)
+ return mca_can_free(c) * c->btree_pages;
+
+ /* Return -1 if we can't do anything right now */
+ if (sc->gfp_mask & __GFP_WAIT)
+ mutex_lock(&c->bucket_lock);
+ else if (!mutex_trylock(&c->bucket_lock))
+ return -1;
+
+ nr /= c->btree_pages;
+ nr = min_t(unsigned long, nr, mca_can_free(c));
+
+ i = 0;
+ list_for_each_entry_safe(b, t, &c->btree_cache_freeable, list) {
+ if (!nr)
+ break;
+
+ if (++i > 3 &&
+ !mca_reap(b, NULL, 0)) {
+ mca_data_free(b);
+ rw_unlock(true, b);
+ --nr;
+ }
+ }
+
+ /*
+ * Can happen right when we first start up, before we've read in any
+ * btree nodes
+ */
+ if (list_empty(&c->btree_cache))
+ goto out;
+
+ for (i = 0; nr && i < c->bucket_cache_used; i++) {
+ b = list_first_entry(&c->btree_cache, struct btree, list);
+ list_rotate_left(&c->btree_cache);
+
+ if (!b->accessed &&
+ !mca_reap(b, NULL, 0)) {
+ mca_bucket_free(b);
+ mca_data_free(b);
+ rw_unlock(true, b);
+ --nr;
+ } else
+ b->accessed = 0;
+ }
+out:
+ nr = mca_can_free(c) * c->btree_pages;
+ mutex_unlock(&c->bucket_lock);
+ return nr;
+}
+
+void bch_btree_cache_free(struct cache_set *c)
+{
+ struct btree *b;
+ struct closure cl;
+ closure_init_stack(&cl);
+
+ if (c->shrink.list.next)
+ unregister_shrinker(&c->shrink);
+
+ mutex_lock(&c->bucket_lock);
+
+#ifdef CONFIG_BCACHE_DEBUG
+ if (c->verify_data)
+ list_move(&c->verify_data->list, &c->btree_cache);
+#endif
+
+ list_splice(&c->btree_cache_freeable,
+ &c->btree_cache);
+
+ while (!list_empty(&c->btree_cache)) {
+ b = list_first_entry(&c->btree_cache, struct btree, list);
+
+ if (btree_node_dirty(b))
+ btree_complete_write(b, btree_current_write(b));
+ clear_bit(BTREE_NODE_dirty, &b->flags);
+
+ mca_data_free(b);
+ }
+
+ while (!list_empty(&c->btree_cache_freed)) {
+ b = list_first_entry(&c->btree_cache_freed,
+ struct btree, list);
+ list_del(&b->list);
+ cancel_delayed_work_sync(&b->work);
+ kfree(b);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+int bch_btree_cache_alloc(struct cache_set *c)
+{
+ unsigned i;
+
+ /* XXX: doesn't check for errors */
+
+ closure_init_unlocked(&c->gc);
+
+ for (i = 0; i < mca_reserve(c); i++)
+ mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);
+
+ list_splice_init(&c->btree_cache,
+ &c->btree_cache_freeable);
+
+#ifdef CONFIG_BCACHE_DEBUG
+ mutex_init(&c->verify_lock);
+
+ c->verify_data = mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);
+
+ if (c->verify_data &&
+ c->verify_data->sets[0].data)
+ list_del_init(&c->verify_data->list);
+ else
+ c->verify_data = NULL;
+#endif
+
+ c->shrink.shrink = bch_mca_shrink;
+ c->shrink.seeks = 4;
+ c->shrink.batch = c->btree_pages * 2;
+ register_shrinker(&c->shrink);
+
+ return 0;
+}
+
+/* Btree in memory cache - hash table */
+
+static struct hlist_head *mca_hash(struct cache_set *c, struct bkey *k)
+{
+ return &c->bucket_hash[hash_32(PTR_HASH(c, k), BUCKET_HASH_BITS)];
+}
+
+static struct btree *mca_find(struct cache_set *c, struct bkey *k)
+{
+ struct btree *b;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(b, mca_hash(c, k), hash)
+ if (PTR_HASH(c, &b->key) == PTR_HASH(c, k))
+ goto out;
+ b = NULL;
+out:
+ rcu_read_unlock();
+ return b;
+}
+
+static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k,
+ int level, struct closure *cl)
+{
+ int ret = -ENOMEM;
+ struct btree *i;
+
+ if (!cl)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * Trying to free up some memory - i.e. reuse some btree nodes - may
+ * require initiating IO to flush the dirty part of the node. If we're
+ * running under generic_make_request(), that IO will never finish and
+ * we would deadlock. Returning -EAGAIN causes the cache lookup code to
+ * punt to workqueue and retry.
+ */
+ if (current->bio_list)
+ return ERR_PTR(-EAGAIN);
+
+ if (c->try_harder && c->try_harder != cl) {
+ closure_wait_event_async(&c->try_wait, cl, !c->try_harder);
+ return ERR_PTR(-EAGAIN);
+ }
+
+ /* XXX: tracepoint */
+ c->try_harder = cl;
+ c->try_harder_start = local_clock();
+retry:
+ list_for_each_entry_reverse(i, &c->btree_cache, list) {
+ int r = mca_reap(i, cl, btree_order(k));
+ if (!r)
+ return i;
+ if (r != -ENOMEM)
+ ret = r;
+ }
+
+ if (ret == -EAGAIN &&
+ closure_blocking(cl)) {
+ mutex_unlock(&c->bucket_lock);
+ closure_sync(cl);
+ mutex_lock(&c->bucket_lock);
+ goto retry;
+ }
+
+ return ERR_PTR(ret);
+}
+
+/*
+ * We can only have one thread cannibalizing other cached btree nodes at a time,
+ * or we'll deadlock. We use an open coded mutex to ensure that, which a
+ * cannibalize_bucket() will take. This means every time we unlock the root of
+ * the btree, we need to release this lock if we have it held.
+ */
+void bch_cannibalize_unlock(struct cache_set *c, struct closure *cl)
+{
+ if (c->try_harder == cl) {
+ time_stats_update(&c->try_harder_time, c->try_harder_start);
+ c->try_harder = NULL;
+ __closure_wake_up(&c->try_wait);
+ }
+}
+
+static struct btree *mca_alloc(struct cache_set *c, struct bkey *k,
+ int level, struct closure *cl)
+{
+ struct btree *b;
+
+ lockdep_assert_held(&c->bucket_lock);
+
+ if (mca_find(c, k))
+ return NULL;
+
+ /* btree_free() doesn't free memory; it sticks the node on the end of
+ * the list. Check if there's any freed nodes there:
+ */
+ list_for_each_entry(b, &c->btree_cache_freeable, list)
+ if (!mca_reap(b, NULL, btree_order(k)))
+ goto out;
+
+ /* We never free struct btree itself, just the memory that holds the on
+ * disk node. Check the freed list before allocating a new one:
+ */
+ list_for_each_entry(b, &c->btree_cache_freed, list)
+ if (!mca_reap(b, NULL, 0)) {
+ mca_data_alloc(b, k, __GFP_NOWARN|GFP_NOIO);
+ if (!b->sets[0].data)
+ goto err;
+ else
+ goto out;
+ }
+
+ b = mca_bucket_alloc(c, k, __GFP_NOWARN|GFP_NOIO);
+ if (!b)
+ goto err;
+
+ BUG_ON(!down_write_trylock(&b->lock));
+ if (!b->sets->data)
+ goto err;
+out:
+ BUG_ON(!closure_is_unlocked(&b->io.cl));
+
+ bkey_copy(&b->key, k);
+ list_move(&b->list, &c->btree_cache);
+ hlist_del_init_rcu(&b->hash);
+ hlist_add_head_rcu(&b->hash, mca_hash(c, k));
+
+ lock_set_subclass(&b->lock.dep_map, level + 1, _THIS_IP_);
+ b->level = level;
+
+ mca_reinit(b);
+
+ return b;
+err:
+ if (b)
+ rw_unlock(true, b);
+
+ b = mca_cannibalize(c, k, level, cl);
+ if (!IS_ERR(b))
+ goto out;
+
+ return b;
+}
+
+/**
+ * bch_btree_node_get - find a btree node in the cache and lock it, reading it
+ * in from disk if necessary.
+ *
+ * If IO is necessary, it uses the closure embedded in struct btree_op to wait;
+ * if that closure is in non blocking mode, will return -EAGAIN.
+ *
+ * The btree node will have either a read or a write lock held, depending on
+ * level and op->lock.
+ */
+struct btree *bch_btree_node_get(struct cache_set *c, struct bkey *k,
+ int level, struct btree_op *op)
+{
+ int i = 0;
+ bool write = level <= op->lock;
+ struct btree *b;
+
+ BUG_ON(level < 0);
+retry:
+ b = mca_find(c, k);
+
+ if (!b) {
+ mutex_lock(&c->bucket_lock);
+ b = mca_alloc(c, k, level, &op->cl);
+ mutex_unlock(&c->bucket_lock);
+
+ if (!b)
+ goto retry;
+ if (IS_ERR(b))
+ return b;
+
+ bch_btree_read(b);
+
+ if (!write)
+ downgrade_write(&b->lock);
+ } else {
+ rw_lock(write, b, level);
+ if (PTR_HASH(c, &b->key) != PTR_HASH(c, k)) {
+ rw_unlock(write, b);
+ goto retry;
+ }
+ BUG_ON(b->level != level);
+ }
+
+ b->accessed = 1;
+
+ for (; i <= b->nsets && b->sets[i].size; i++) {
+ prefetch(b->sets[i].tree);
+ prefetch(b->sets[i].data);
+ }
+
+ for (; i <= b->nsets; i++)
+ prefetch(b->sets[i].data);
+
+ if (!closure_wait_event(&b->io.wait, &op->cl,
+ btree_node_read_done(b))) {
+ rw_unlock(write, b);
+ b = ERR_PTR(-EAGAIN);
+ } else if (btree_node_io_error(b)) {
+ rw_unlock(write, b);
+ b = ERR_PTR(-EIO);
+ } else
+ BUG_ON(!b->written);
+
+ return b;
+}
+
+static void btree_node_prefetch(struct cache_set *c, struct bkey *k, int level)
+{
+ struct btree *b;
+
+ mutex_lock(&c->bucket_lock);
+ b = mca_alloc(c, k, level, NULL);
+ mutex_unlock(&c->bucket_lock);
+
+ if (!IS_ERR_OR_NULL(b)) {
+ bch_btree_read(b);
+ rw_unlock(true, b);
+ }
+}
+
+/* Btree alloc */
+
+static void btree_node_free(struct btree *b, struct btree_op *op)
+{
+ unsigned i;
+
+ /*
+ * The BUG_ON() in btree_node_get() implies that we must have a write
+ * lock on parent to free or even invalidate a node
+ */
+ BUG_ON(op->lock <= b->level);
+ BUG_ON(b == b->c->root);
+ pr_debug("bucket %s", pbtree(b));
+
+ if (btree_node_dirty(b))
+ btree_complete_write(b, btree_current_write(b));
+ clear_bit(BTREE_NODE_dirty, &b->flags);
+
+ if (b->prio_blocked &&
+ !atomic_sub_return(b->prio_blocked, &b->c->prio_blocked))
+ closure_wake_up(&b->c->bucket_wait);
+
+ b->prio_blocked = 0;
+
+ cancel_delayed_work(&b->work);
+
+ mutex_lock(&b->c->bucket_lock);
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++) {
+ BUG_ON(atomic_read(&PTR_BUCKET(b->c, &b->key, i)->pin));
+
+ bch_inc_gen(PTR_CACHE(b->c, &b->key, i),
+ PTR_BUCKET(b->c, &b->key, i));
+ }
+
+ bch_bucket_free(b->c, &b->key);
+ mca_bucket_free(b);
+ mutex_unlock(&b->c->bucket_lock);
+}
+
+struct btree *bch_btree_node_alloc(struct cache_set *c, int level,
+ struct closure *cl)
+{
+ BKEY_PADDED(key) k;
+ struct btree *b = ERR_PTR(-EAGAIN);
+
+ mutex_lock(&c->bucket_lock);
+retry:
+ if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, cl))
+ goto err;
+
+ SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
+
+ b = mca_alloc(c, &k.key, level, cl);
+ if (IS_ERR(b))
+ goto err_free;
+
+ if (!b) {
+ cache_bug(c, "Tried to allocate bucket"
+ " that was in btree cache");
+ __bkey_put(c, &k.key);
+ goto retry;
+ }
+
+ set_btree_node_read_done(b);
+ b->accessed = 1;
+ bch_bset_init_next(b);
+
+ mutex_unlock(&c->bucket_lock);
+ return b;
+err_free:
+ bch_bucket_free(c, &k.key);
+ __bkey_put(c, &k.key);
+err:
+ mutex_unlock(&c->bucket_lock);
+ return b;
+}
+
+static struct btree *btree_node_alloc_replacement(struct btree *b,
+ struct closure *cl)
+{
+ struct btree *n = bch_btree_node_alloc(b->c, b->level, cl);
+ if (!IS_ERR_OR_NULL(n))
+ bch_btree_sort_into(b, n);
+
+ return n;
+}
+
+/* Garbage collection */
+
+uint8_t __bch_btree_mark_key(struct cache_set *c, int level, struct bkey *k)
+{
+ uint8_t stale = 0;
+ unsigned i;
+ struct bucket *g;
+
+ /*
+ * ptr_invalid() can't return true for the keys that mark btree nodes as
+ * freed, but since ptr_bad() returns true we'll never actually use them
+ * for anything and thus we don't want mark their pointers here
+ */
+ if (!bkey_cmp(k, &ZERO_KEY))
+ return stale;
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ if (!ptr_available(c, k, i))
+ continue;
+
+ g = PTR_BUCKET(c, k, i);
+
+ if (gen_after(g->gc_gen, PTR_GEN(k, i)))
+ g->gc_gen = PTR_GEN(k, i);
+
+ if (ptr_stale(c, k, i)) {
+ stale = max(stale, ptr_stale(c, k, i));
+ continue;
+ }
+
+ cache_bug_on(GC_MARK(g) &&
+ (GC_MARK(g) == GC_MARK_METADATA) != (level != 0),
+ c, "inconsistent ptrs: mark = %llu, level = %i",
+ GC_MARK(g), level);
+
+ if (level)
+ SET_GC_MARK(g, GC_MARK_METADATA);
+ else if (KEY_DIRTY(k))
+ SET_GC_MARK(g, GC_MARK_DIRTY);
+
+ /* guard against overflow */
+ SET_GC_SECTORS_USED(g, min_t(unsigned,
+ GC_SECTORS_USED(g) + KEY_SIZE(k),
+ (1 << 14) - 1));
+
+ BUG_ON(!GC_SECTORS_USED(g));
+ }
+
+ return stale;
+}
+
+#define btree_mark_key(b, k) __bch_btree_mark_key(b->c, b->level, k)
+
+static int btree_gc_mark_node(struct btree *b, unsigned *keys,
+ struct gc_stat *gc)
+{
+ uint8_t stale = 0;
+ unsigned last_dev = -1;
+ struct bcache_device *d = NULL;
+ struct bkey *k;
+ struct btree_iter iter;
+ struct bset_tree *t;
+
+ gc->nodes++;
+
+ for_each_key_filter(b, k, &iter, bch_ptr_invalid) {
+ if (last_dev != KEY_INODE(k)) {
+ last_dev = KEY_INODE(k);
+
+ d = KEY_INODE(k) < b->c->nr_uuids
+ ? b->c->devices[last_dev]
+ : NULL;
+ }
+
+ stale = max(stale, btree_mark_key(b, k));
+
+ if (bch_ptr_bad(b, k))
+ continue;
+
+ *keys += bkey_u64s(k);
+
+ gc->key_bytes += bkey_u64s(k);
+ gc->nkeys++;
+
+ gc->data += KEY_SIZE(k);
+ if (KEY_DIRTY(k)) {
+ gc->dirty += KEY_SIZE(k);
+ if (d)
+ d->sectors_dirty_gc += KEY_SIZE(k);
+ }
+ }
+
+ for (t = b->sets; t <= &b->sets[b->nsets]; t++)
+ btree_bug_on(t->size &&
+ bset_written(b, t) &&
+ bkey_cmp(&b->key, &t->end) < 0,
+ b, "found short btree key in gc");
+
+ return stale;
+}
+
+static struct btree *btree_gc_alloc(struct btree *b, struct bkey *k,
+ struct btree_op *op)
+{
+ /*
+ * We block priorities from being written for the duration of garbage
+ * collection, so we can't sleep in btree_alloc() ->
+ * bch_bucket_alloc_set(), or we'd risk deadlock - so we don't pass it
+ * our closure.
+ */
+ struct btree *n = btree_node_alloc_replacement(b, NULL);
+
+ if (!IS_ERR_OR_NULL(n)) {
+ swap(b, n);
+
+ memcpy(k->ptr, b->key.ptr,
+ sizeof(uint64_t) * KEY_PTRS(&b->key));
+
+ __bkey_put(b->c, &b->key);
+ atomic_inc(&b->c->prio_blocked);
+ b->prio_blocked++;
+
+ btree_node_free(n, op);
+ up_write(&n->lock);
+ }
+
+ return b;
+}
+
+/*
+ * Leaving this at 2 until we've got incremental garbage collection done; it
+ * could be higher (and has been tested with 4) except that garbage collection
+ * could take much longer, adversely affecting latency.
+ */
+#define GC_MERGE_NODES 2U
+
+struct gc_merge_info {
+ struct btree *b;
+ struct bkey *k;
+ unsigned keys;
+};
+
+static void btree_gc_coalesce(struct btree *b, struct btree_op *op,
+ struct gc_stat *gc, struct gc_merge_info *r)
+{
+ unsigned nodes = 0, keys = 0, blocks;
+ int i;
+
+ while (nodes < GC_MERGE_NODES && r[nodes].b)
+ keys += r[nodes++].keys;
+
+ blocks = btree_default_blocks(b->c) * 2 / 3;
+
+ if (nodes < 2 ||
+ __set_blocks(b->sets[0].data, keys, b->c) > blocks * (nodes - 1))
+ return;
+
+ for (i = nodes - 1; i >= 0; --i) {
+ if (r[i].b->written)
+ r[i].b = btree_gc_alloc(r[i].b, r[i].k, op);
+
+ if (r[i].b->written)
+ return;
+ }
+
+ for (i = nodes - 1; i > 0; --i) {
+ struct bset *n1 = r[i].b->sets->data;
+ struct bset *n2 = r[i - 1].b->sets->data;
+ struct bkey *k, *last = NULL;
+
+ keys = 0;
+
+ if (i == 1) {
+ /*
+ * Last node we're not getting rid of - we're getting
+ * rid of the node at r[0]. Have to try and fit all of
+ * the remaining keys into this node; we can't ensure
+ * they will always fit due to rounding and variable
+ * length keys (shouldn't be possible in practice,
+ * though)
+ */
+ if (__set_blocks(n1, n1->keys + r->keys,
+ b->c) > btree_blocks(r[i].b))
+ return;
+
+ keys = n2->keys;
+ last = &r->b->key;
+ } else
+ for (k = n2->start;
+ k < end(n2);
+ k = bkey_next(k)) {
+ if (__set_blocks(n1, n1->keys + keys +
+ bkey_u64s(k), b->c) > blocks)
+ break;
+
+ last = k;
+ keys += bkey_u64s(k);
+ }
+
+ BUG_ON(__set_blocks(n1, n1->keys + keys,
+ b->c) > btree_blocks(r[i].b));
+
+ if (last) {
+ bkey_copy_key(&r[i].b->key, last);
+ bkey_copy_key(r[i].k, last);
+ }
+
+ memcpy(end(n1),
+ n2->start,
+ (void *) node(n2, keys) - (void *) n2->start);
+
+ n1->keys += keys;
+
+ memmove(n2->start,
+ node(n2, keys),
+ (void *) end(n2) - (void *) node(n2, keys));
+
+ n2->keys -= keys;
+
+ r[i].keys = n1->keys;
+ r[i - 1].keys = n2->keys;
+ }
+
+ btree_node_free(r->b, op);
+ up_write(&r->b->lock);
+
+ pr_debug("coalesced %u nodes", nodes);
+
+ gc->nodes--;
+ nodes--;
+
+ memmove(&r[0], &r[1], sizeof(struct gc_merge_info) * nodes);
+ memset(&r[nodes], 0, sizeof(struct gc_merge_info));
+}
+
+static int btree_gc_recurse(struct btree *b, struct btree_op *op,
+ struct closure *writes, struct gc_stat *gc)
+{
+ void write(struct btree *r)
+ {
+ if (!r->written)
+ bch_btree_write(r, true, op);
+ else if (btree_node_dirty(r)) {
+ BUG_ON(btree_current_write(r)->owner);
+ btree_current_write(r)->owner = writes;
+ closure_get(writes);
+
+ bch_btree_write(r, true, NULL);
+ }
+
+ up_write(&r->lock);
+ }
+
+ int ret = 0, stale;
+ unsigned i;
+ struct gc_merge_info r[GC_MERGE_NODES];
+
+ memset(r, 0, sizeof(r));
+
+ while ((r->k = bch_next_recurse_key(b, &b->c->gc_done))) {
+ r->b = bch_btree_node_get(b->c, r->k, b->level - 1, op);
+
+ if (IS_ERR(r->b)) {
+ ret = PTR_ERR(r->b);
+ break;
+ }
+
+ r->keys = 0;
+ stale = btree_gc_mark_node(r->b, &r->keys, gc);
+
+ if (!b->written &&
+ (r->b->level || stale > 10 ||
+ b->c->gc_always_rewrite))
+ r->b = btree_gc_alloc(r->b, r->k, op);
+
+ if (r->b->level)
+ ret = btree_gc_recurse(r->b, op, writes, gc);
+
+ if (ret) {
+ write(r->b);
+ break;
+ }
+
+ bkey_copy_key(&b->c->gc_done, r->k);
+
+ if (!b->written)
+ btree_gc_coalesce(b, op, gc, r);
+
+ if (r[GC_MERGE_NODES - 1].b)
+ write(r[GC_MERGE_NODES - 1].b);
+
+ memmove(&r[1], &r[0],
+ sizeof(struct gc_merge_info) * (GC_MERGE_NODES - 1));
+
+ /* When we've got incremental GC working, we'll want to do
+ * if (should_resched())
+ * return -EAGAIN;
+ */
+ cond_resched();
+#if 0
+ if (need_resched()) {
+ ret = -EAGAIN;
+ break;
+ }
+#endif
+ }
+
+ for (i = 1; i < GC_MERGE_NODES && r[i].b; i++)
+ write(r[i].b);
+
+ /* Might have freed some children, must remove their keys */
+ if (!b->written)
+ bch_btree_sort(b);
+
+ return ret;
+}
+
+static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
+ struct closure *writes, struct gc_stat *gc)
+{
+ struct btree *n = NULL;
+ unsigned keys = 0;
+ int ret = 0, stale = btree_gc_mark_node(b, &keys, gc);
+
+ if (b->level || stale > 10)
+ n = btree_node_alloc_replacement(b, NULL);
+
+ if (!IS_ERR_OR_NULL(n))
+ swap(b, n);
+
+ if (b->level)
+ ret = btree_gc_recurse(b, op, writes, gc);
+
+ if (!b->written || btree_node_dirty(b)) {
+ atomic_inc(&b->c->prio_blocked);
+ b->prio_blocked++;
+ bch_btree_write(b, true, n ? op : NULL);
+ }
+
+ if (!IS_ERR_OR_NULL(n)) {
+ closure_sync(&op->cl);
+ bch_btree_set_root(b);
+ btree_node_free(n, op);
+ rw_unlock(true, b);
+ }
+
+ return ret;
+}
+
+static void btree_gc_start(struct cache_set *c)
+{
+ struct cache *ca;
+ struct bucket *b;
+ struct bcache_device **d;
+ unsigned i;
+
+ if (!c->gc_mark_valid)
+ return;
+
+ mutex_lock(&c->bucket_lock);
+
+ c->gc_mark_valid = 0;
+ c->gc_done = ZERO_KEY;
+
+ for_each_cache(ca, c, i)
+ for_each_bucket(b, ca) {
+ b->gc_gen = b->gen;
+ if (!atomic_read(&b->pin))
+ SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
+ }
+
+ for (d = c->devices;
+ d < c->devices + c->nr_uuids;
+ d++)
+ if (*d)
+ (*d)->sectors_dirty_gc = 0;
+
+ mutex_unlock(&c->bucket_lock);
+}
+
+size_t bch_btree_gc_finish(struct cache_set *c)
+{
+ size_t available = 0;
+ struct bucket *b;
+ struct cache *ca;
+ struct bcache_device **d;
+ unsigned i;
+
+ mutex_lock(&c->bucket_lock);
+
+ set_gc_sectors(c);
+ c->gc_mark_valid = 1;
+ c->need_gc = 0;
+
+ if (c->root)
+ for (i = 0; i < KEY_PTRS(&c->root->key); i++)
+ SET_GC_MARK(PTR_BUCKET(c, &c->root->key, i),
+ GC_MARK_METADATA);
+
+ for (i = 0; i < KEY_PTRS(&c->uuid_bucket); i++)
+ SET_GC_MARK(PTR_BUCKET(c, &c->uuid_bucket, i),
+ GC_MARK_METADATA);
+
+ for_each_cache(ca, c, i) {
+ uint64_t *i;
+
+ ca->invalidate_needs_gc = 0;
+
+ for (i = ca->sb.d; i < ca->sb.d + ca->sb.keys; i++)
+ SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
+
+ for (i = ca->prio_buckets;
+ i < ca->prio_buckets + prio_buckets(ca) * 2; i++)
+ SET_GC_MARK(ca->buckets + *i, GC_MARK_METADATA);
+
+ for_each_bucket(b, ca) {
+ b->last_gc = b->gc_gen;
+ c->need_gc = max(c->need_gc, bucket_gc_gen(b));
+
+ if (!atomic_read(&b->pin) &&
+ GC_MARK(b) == GC_MARK_RECLAIMABLE) {
+ available++;
+ if (!GC_SECTORS_USED(b))
+ bch_bucket_add_unused(ca, b);
+ }
+ }
+ }
+
+ for (d = c->devices;
+ d < c->devices + c->nr_uuids;
+ d++)
+ if (*d) {
+ unsigned long last =
+ atomic_long_read(&((*d)->sectors_dirty));
+ long difference = (*d)->sectors_dirty_gc - last;
+
+ pr_debug("sectors dirty off by %li", difference);
+
+ (*d)->sectors_dirty_last += difference;
+
+ atomic_long_set(&((*d)->sectors_dirty),
+ (*d)->sectors_dirty_gc);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+ return available;
+}
+
+static void bch_btree_gc(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, gc.cl);
+ int ret;
+ unsigned long available;
+ struct gc_stat stats;
+ struct closure writes;
+ struct btree_op op;
+
+ uint64_t start_time = local_clock();
+ trace_bcache_gc_start(c->sb.set_uuid);
+ blktrace_msg_all(c, "Starting gc");
+
+ memset(&stats, 0, sizeof(struct gc_stat));
+ closure_init_stack(&writes);
+ bch_btree_op_init_stack(&op);
+ op.lock = SHRT_MAX;
+
+ btree_gc_start(c);
+
+ ret = btree_root(gc_root, c, &op, &writes, &stats);
+ closure_sync(&op.cl);
+ closure_sync(&writes);
+
+ if (ret) {
+ blktrace_msg_all(c, "Stopped gc");
+ pr_warn("gc failed!");
+
+ continue_at(cl, bch_btree_gc, bch_gc_wq);
+ }
+
+ /* Possibly wait for new UUIDs or whatever to hit disk */
+ bch_journal_meta(c, &op.cl);
+ closure_sync(&op.cl);
+
+ available = bch_btree_gc_finish(c);
+
+ time_stats_update(&c->btree_gc_time, start_time);
+
+ stats.key_bytes *= sizeof(uint64_t);
+ stats.dirty <<= 9;
+ stats.data <<= 9;
+ stats.in_use = (c->nbuckets - available) * 100 / c->nbuckets;
+ memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat));
+ blktrace_msg_all(c, "Finished gc");
+
+ trace_bcache_gc_end(c->sb.set_uuid);
+ wake_up(&c->alloc_wait);
+ closure_wake_up(&c->bucket_wait);
+
+ continue_at(cl, bch_moving_gc, bch_gc_wq);
+}
+
+void bch_queue_gc(struct cache_set *c)
+{
+ closure_trylock_call(&c->gc.cl, bch_btree_gc, bch_gc_wq, &c->cl);
+}
+
+/* Initial partial gc */
+
+static int bch_btree_check_recurse(struct btree *b, struct btree_op *op,
+ unsigned long **seen)
+{
+ int ret;
+ unsigned i;
+ struct bkey *k;
+ struct bucket *g;
+ struct btree_iter iter;
+
+ for_each_key_filter(b, k, &iter, bch_ptr_invalid) {
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ if (!ptr_available(b->c, k, i))
+ continue;
+
+ g = PTR_BUCKET(b->c, k, i);
+
+ if (!__test_and_set_bit(PTR_BUCKET_NR(b->c, k, i),
+ seen[PTR_DEV(k, i)]) ||
+ !ptr_stale(b->c, k, i)) {
+ g->gen = PTR_GEN(k, i);
+
+ if (b->level)
+ g->prio = BTREE_PRIO;
+ else if (g->prio == BTREE_PRIO)
+ g->prio = INITIAL_PRIO;
+ }
+ }
+
+ btree_mark_key(b, k);
+ }
+
+ if (b->level) {
+ k = bch_next_recurse_key(b, &ZERO_KEY);
+
+ while (k) {
+ struct bkey *p = bch_next_recurse_key(b, k);
+ if (p)
+ btree_node_prefetch(b->c, p, b->level - 1);
+
+ ret = btree(check_recurse, k, b, op, seen);
+ if (ret)
+ return ret;
+
+ k = p;
+ }
+ }
+
+ return 0;
+}
+
+int bch_btree_check(struct cache_set *c, struct btree_op *op)
+{
+ int ret = -ENOMEM;
+ unsigned i;
+ unsigned long *seen[MAX_CACHES_PER_SET];
+
+ memset(seen, 0, sizeof(seen));
+
+ for (i = 0; c->cache[i]; i++) {
+ size_t n = DIV_ROUND_UP(c->cache[i]->sb.nbuckets, 8);
+ seen[i] = kmalloc(n, GFP_KERNEL);
+ if (!seen[i])
+ goto err;
+
+ /* Disables the seen array until prio_read() uses it too */
+ memset(seen[i], 0xFF, n);
+ }
+
+ ret = btree_root(check_recurse, c, op, seen);
+err:
+ for (i = 0; i < MAX_CACHES_PER_SET; i++)
+ kfree(seen[i]);
+ return ret;
+}
+
+/* Btree insertion */
+
+static void shift_keys(struct btree *b, struct bkey *where, struct bkey *insert)
+{
+ struct bset *i = b->sets[b->nsets].data;
+
+ memmove((uint64_t *) where + bkey_u64s(insert),
+ where,
+ (void *) end(i) - (void *) where);
+
+ i->keys += bkey_u64s(insert);
+ bkey_copy(where, insert);
+ bch_bset_fix_lookup_table(b, where);
+}
+
+static bool fix_overlapping_extents(struct btree *b,
+ struct bkey *insert,
+ struct btree_iter *iter,
+ struct btree_op *op)
+{
+ void subtract_dirty(struct bkey *k, int sectors)
+ {
+ struct bcache_device *d = b->c->devices[KEY_INODE(k)];
+
+ if (KEY_DIRTY(k) && d)
+ atomic_long_sub(sectors, &d->sectors_dirty);
+ }
+
+ unsigned old_size, sectors_found = 0;
+
+ while (1) {
+ struct bkey *k = bch_btree_iter_next(iter);
+ if (!k ||
+ bkey_cmp(&START_KEY(k), insert) >= 0)
+ break;
+
+ if (bkey_cmp(k, &START_KEY(insert)) <= 0)
+ continue;
+
+ old_size = KEY_SIZE(k);
+
+ /*
+ * We might overlap with 0 size extents; we can't skip these
+ * because if they're in the set we're inserting to we have to
+ * adjust them so they don't overlap with the key we're
+ * inserting. But we don't want to check them for BTREE_REPLACE
+ * operations.
+ */
+
+ if (op->type == BTREE_REPLACE &&
+ KEY_SIZE(k)) {
+ /*
+ * k might have been split since we inserted/found the
+ * key we're replacing
+ */
+ unsigned i;
+ uint64_t offset = KEY_START(k) -
+ KEY_START(&op->replace);
+
+ /* But it must be a subset of the replace key */
+ if (KEY_START(k) < KEY_START(&op->replace) ||
+ KEY_OFFSET(k) > KEY_OFFSET(&op->replace))
+ goto check_failed;
+
+ /* We didn't find a key that we were supposed to */
+ if (KEY_START(k) > KEY_START(insert) + sectors_found)
+ goto check_failed;
+
+ if (KEY_PTRS(&op->replace) != KEY_PTRS(k))
+ goto check_failed;
+
+ /* skip past gen */
+ offset <<= 8;
+
+ BUG_ON(!KEY_PTRS(&op->replace));
+
+ for (i = 0; i < KEY_PTRS(&op->replace); i++)
+ if (k->ptr[i] != op->replace.ptr[i] + offset)
+ goto check_failed;
+
+ sectors_found = KEY_OFFSET(k) - KEY_START(insert);
+ }
+
+ if (bkey_cmp(insert, k) < 0 &&
+ bkey_cmp(&START_KEY(insert), &START_KEY(k)) > 0) {
+ /*
+ * We overlapped in the middle of an existing key: that
+ * means we have to split the old key. But we have to do
+ * slightly different things depending on whether the
+ * old key has been written out yet.
+ */
+
+ struct bkey *top;
+
+ subtract_dirty(k, KEY_SIZE(insert));
+
+ if (bkey_written(b, k)) {
+ /*
+ * We insert a new key to cover the top of the
+ * old key, and the old key is modified in place
+ * to represent the bottom split.
+ *
+ * It's completely arbitrary whether the new key
+ * is the top or the bottom, but it has to match
+ * up with what btree_sort_fixup() does - it
+ * doesn't check for this kind of overlap, it
+ * depends on us inserting a new key for the top
+ * here.
+ */
+ top = bch_bset_search(b, &b->sets[b->nsets],
+ insert);
+ shift_keys(b, top, k);
+ } else {
+ BKEY_PADDED(key) temp;
+ bkey_copy(&temp.key, k);
+ shift_keys(b, k, &temp.key);
+ top = bkey_next(k);
+ }
+
+ bch_cut_front(insert, top);
+ bch_cut_back(&START_KEY(insert), k);
+ bch_bset_fix_invalidated_key(b, k);
+ return false;
+ }
+
+ if (bkey_cmp(insert, k) < 0) {
+ bch_cut_front(insert, k);
+ } else {
+ if (bkey_written(b, k) &&
+ bkey_cmp(&START_KEY(insert), &START_KEY(k)) <= 0) {
+ /*
+ * Completely overwrote, so we don't have to
+ * invalidate the binary search tree
+ */
+ bch_cut_front(k, k);
+ } else {
+ __bch_cut_back(&START_KEY(insert), k);
+ bch_bset_fix_invalidated_key(b, k);
+ }
+ }
+
+ subtract_dirty(k, old_size - KEY_SIZE(k));
+ }
+
+check_failed:
+ if (op->type == BTREE_REPLACE) {
+ if (!sectors_found) {
+ op->insert_collision = true;
+ return true;
+ } else if (sectors_found < KEY_SIZE(insert)) {
+ SET_KEY_OFFSET(insert, KEY_OFFSET(insert) -
+ (KEY_SIZE(insert) - sectors_found));
+ SET_KEY_SIZE(insert, sectors_found);
+ }
+ }
+
+ return false;
+}
+
+static bool btree_insert_key(struct btree *b, struct btree_op *op,
+ struct bkey *k)
+{
+ struct bset *i = b->sets[b->nsets].data;
+ struct bkey *m, *prev;
+ const char *status = "insert";
+
+ BUG_ON(bkey_cmp(k, &b->key) > 0);
+ BUG_ON(b->level && !KEY_PTRS(k));
+ BUG_ON(!b->level && !KEY_OFFSET(k));
+
+ if (!b->level) {
+ struct btree_iter iter;
+ struct bkey search = KEY(KEY_INODE(k), KEY_START(k), 0);
+
+ /*
+ * bset_search() returns the first key that is strictly greater
+ * than the search key - but for back merging, we want to find
+ * the first key that is greater than or equal to KEY_START(k) -
+ * unless KEY_START(k) is 0.
+ */
+ if (KEY_OFFSET(&search))
+ SET_KEY_OFFSET(&search, KEY_OFFSET(&search) - 1);
+
+ prev = NULL;
+ m = bch_btree_iter_init(b, &iter, &search);
+
+ if (fix_overlapping_extents(b, k, &iter, op))
+ return false;
+
+ while (m != end(i) &&
+ bkey_cmp(k, &START_KEY(m)) > 0)
+ prev = m, m = bkey_next(m);
+
+ if (key_merging_disabled(b->c))
+ goto insert;
+
+ /* prev is in the tree, if we merge we're done */
+ status = "back merging";
+ if (prev &&
+ bch_bkey_try_merge(b, prev, k))
+ goto merged;
+
+ status = "overwrote front";
+ if (m != end(i) &&
+ KEY_PTRS(m) == KEY_PTRS(k) && !KEY_SIZE(m))
+ goto copy;
+
+ status = "front merge";
+ if (m != end(i) &&
+ bch_bkey_try_merge(b, k, m))
+ goto copy;
+ } else
+ m = bch_bset_search(b, &b->sets[b->nsets], k);
+
+insert: shift_keys(b, m, k);
+copy: bkey_copy(m, k);
+merged:
+ bch_check_keys(b, "%s for %s at %s: %s", status,
+ op_type(op), pbtree(b), pkey(k));
+ bch_check_key_order_msg(b, i, "%s for %s at %s: %s", status,
+ op_type(op), pbtree(b), pkey(k));
+
+ if (b->level && !KEY_OFFSET(k))
+ b->prio_blocked++;
+
+ pr_debug("%s for %s at %s: %s", status,
+ op_type(op), pbtree(b), pkey(k));
+
+ return true;
+}
+
+bool bch_btree_insert_keys(struct btree *b, struct btree_op *op)
+{
+ bool ret = false;
+ struct bkey *k;
+ unsigned oldsize = bch_count_data(b);
+
+ while ((k = bch_keylist_pop(&op->keys))) {
+ bkey_put(b->c, k, b->level);
+ ret |= btree_insert_key(b, op, k);
+ }
+
+ BUG_ON(bch_count_data(b) < oldsize);
+ return ret;
+}
+
+bool bch_btree_insert_check_key(struct btree *b, struct btree_op *op,
+ struct bio *bio)
+{
+ bool ret = false;
+ uint64_t btree_ptr = b->key.ptr[0];
+ unsigned long seq = b->seq;
+ BKEY_PADDED(k) tmp;
+
+ rw_unlock(false, b);
+ rw_lock(true, b, b->level);
+
+ if (b->key.ptr[0] != btree_ptr ||
+ b->seq != seq + 1 ||
+ should_split(b))
+ goto out;
+
+ op->replace = KEY(op->inode, bio_end(bio), bio_sectors(bio));
+
+ SET_KEY_PTRS(&op->replace, 1);
+ get_random_bytes(&op->replace.ptr[0], sizeof(uint64_t));
+
+ SET_PTR_DEV(&op->replace, 0, PTR_CHECK_DEV);
+
+ bkey_copy(&tmp.k, &op->replace);
+
+ BUG_ON(op->type != BTREE_INSERT);
+ BUG_ON(!btree_insert_key(b, op, &tmp.k));
+ bch_btree_write(b, false, NULL);
+ ret = true;
+out:
+ downgrade_write(&b->lock);
+ return ret;
+}
+
+static int btree_split(struct btree *b, struct btree_op *op)
+{
+ bool split, root = b == b->c->root;
+ struct btree *n1, *n2 = NULL, *n3 = NULL;
+ uint64_t start_time = local_clock();
+
+ if (b->level)
+ set_closure_blocking(&op->cl);
+
+ n1 = btree_node_alloc_replacement(b, &op->cl);
+ if (IS_ERR(n1))
+ goto err;
+
+ split = set_blocks(n1->sets[0].data, n1->c) > (btree_blocks(b) * 4) / 5;
+
+ pr_debug("%ssplitting at %s keys %i", split ? "" : "not ",
+ pbtree(b), n1->sets[0].data->keys);
+
+ if (split) {
+ unsigned keys = 0;
+
+ n2 = bch_btree_node_alloc(b->c, b->level, &op->cl);
+ if (IS_ERR(n2))
+ goto err_free1;
+
+ if (root) {
+ n3 = bch_btree_node_alloc(b->c, b->level + 1, &op->cl);
+ if (IS_ERR(n3))
+ goto err_free2;
+ }
+
+ bch_btree_insert_keys(n1, op);
+
+ /* Has to be a linear search because we don't have an auxiliary
+ * search tree yet
+ */
+
+ while (keys < (n1->sets[0].data->keys * 3) / 5)
+ keys += bkey_u64s(node(n1->sets[0].data, keys));
+
+ bkey_copy_key(&n1->key, node(n1->sets[0].data, keys));
+ keys += bkey_u64s(node(n1->sets[0].data, keys));
+
+ n2->sets[0].data->keys = n1->sets[0].data->keys - keys;
+ n1->sets[0].data->keys = keys;
+
+ memcpy(n2->sets[0].data->start,
+ end(n1->sets[0].data),
+ n2->sets[0].data->keys * sizeof(uint64_t));
+
+ bkey_copy_key(&n2->key, &b->key);
+
+ bch_keylist_add(&op->keys, &n2->key);
+ bch_btree_write(n2, true, op);
+ rw_unlock(true, n2);
+ } else
+ bch_btree_insert_keys(n1, op);
+
+ bch_keylist_add(&op->keys, &n1->key);
+ bch_btree_write(n1, true, op);
+
+ if (n3) {
+ bkey_copy_key(&n3->key, &MAX_KEY);
+ bch_btree_insert_keys(n3, op);
+ bch_btree_write(n3, true, op);
+
+ closure_sync(&op->cl);
+ bch_btree_set_root(n3);
+ rw_unlock(true, n3);
+ } else if (root) {
+ op->keys.top = op->keys.bottom;
+ closure_sync(&op->cl);
+ bch_btree_set_root(n1);
+ } else {
+ unsigned i;
+
+ bkey_copy(op->keys.top, &b->key);
+ bkey_copy_key(op->keys.top, &ZERO_KEY);
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++) {
+ uint8_t g = PTR_BUCKET(b->c, &b->key, i)->gen + 1;
+
+ SET_PTR_GEN(op->keys.top, i, g);
+ }
+
+ bch_keylist_push(&op->keys);
+ closure_sync(&op->cl);
+ atomic_inc(&b->c->prio_blocked);
+ }
+
+ rw_unlock(true, n1);
+ btree_node_free(b, op);
+
+ time_stats_update(&b->c->btree_split_time, start_time);
+
+ return 0;
+err_free2:
+ __bkey_put(n2->c, &n2->key);
+ btree_node_free(n2, op);
+ rw_unlock(true, n2);
+err_free1:
+ __bkey_put(n1->c, &n1->key);
+ btree_node_free(n1, op);
+ rw_unlock(true, n1);
+err:
+ if (n3 == ERR_PTR(-EAGAIN) ||
+ n2 == ERR_PTR(-EAGAIN) ||
+ n1 == ERR_PTR(-EAGAIN))
+ return -EAGAIN;
+
+ pr_warn("couldn't split");
+ return -ENOMEM;
+}
+
+static int bch_btree_insert_recurse(struct btree *b, struct btree_op *op,
+ struct keylist *stack_keys)
+{
+ if (b->level) {
+ int ret;
+ struct bkey *insert = op->keys.bottom;
+ struct bkey *k = bch_next_recurse_key(b, &START_KEY(insert));
+
+ if (!k) {
+ btree_bug(b, "no key to recurse on at level %i/%i",
+ b->level, b->c->root->level);
+
+ op->keys.top = op->keys.bottom;
+ return -EIO;
+ }
+
+ if (bkey_cmp(insert, k) > 0) {
+ unsigned i;
+
+ if (op->type == BTREE_REPLACE) {
+ __bkey_put(b->c, insert);
+ op->keys.top = op->keys.bottom;
+ op->insert_collision = true;
+ return 0;
+ }
+
+ for (i = 0; i < KEY_PTRS(insert); i++)
+ atomic_inc(&PTR_BUCKET(b->c, insert, i)->pin);
+
+ bkey_copy(stack_keys->top, insert);
+
+ bch_cut_back(k, insert);
+ bch_cut_front(k, stack_keys->top);
+
+ bch_keylist_push(stack_keys);
+ }
+
+ ret = btree(insert_recurse, k, b, op, stack_keys);
+ if (ret)
+ return ret;
+ }
+
+ if (!bch_keylist_empty(&op->keys)) {
+ if (should_split(b)) {
+ if (op->lock <= b->c->root->level) {
+ BUG_ON(b->level);
+ op->lock = b->c->root->level + 1;
+ return -EINTR;
+ }
+ return btree_split(b, op);
+ }
+
+ BUG_ON(write_block(b) != b->sets[b->nsets].data);
+
+ if (bch_btree_insert_keys(b, op))
+ bch_btree_write(b, false, op);
+ }
+
+ return 0;
+}
+
+int bch_btree_insert(struct btree_op *op, struct cache_set *c)
+{
+ int ret = 0;
+ struct keylist stack_keys;
+
+ /*
+ * Don't want to block with the btree locked unless we have to,
+ * otherwise we get deadlocks with try_harder and between split/gc
+ */
+ clear_closure_blocking(&op->cl);
+
+ BUG_ON(bch_keylist_empty(&op->keys));
+ bch_keylist_copy(&stack_keys, &op->keys);
+ bch_keylist_init(&op->keys);
+
+ while (!bch_keylist_empty(&stack_keys) ||
+ !bch_keylist_empty(&op->keys)) {
+ if (bch_keylist_empty(&op->keys)) {
+ bch_keylist_add(&op->keys,
+ bch_keylist_pop(&stack_keys));
+ op->lock = 0;
+ }
+
+ ret = btree_root(insert_recurse, c, op, &stack_keys);
+
+ if (ret == -EAGAIN) {
+ ret = 0;
+ closure_sync(&op->cl);
+ } else if (ret) {
+ struct bkey *k;
+
+ pr_err("error %i trying to insert key for %s",
+ ret, op_type(op));
+
+ while ((k = bch_keylist_pop(&stack_keys) ?:
+ bch_keylist_pop(&op->keys)))
+ bkey_put(c, k, 0);
+ }
+ }
+
+ bch_keylist_free(&stack_keys);
+
+ if (op->journal)
+ atomic_dec_bug(op->journal);
+ op->journal = NULL;
+ return ret;
+}
+
+void bch_btree_set_root(struct btree *b)
+{
+ unsigned i;
+
+ BUG_ON(!b->written);
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++)
+ BUG_ON(PTR_BUCKET(b->c, &b->key, i)->prio != BTREE_PRIO);
+
+ mutex_lock(&b->c->bucket_lock);
+ list_del_init(&b->list);
+ mutex_unlock(&b->c->bucket_lock);
+
+ b->c->root = b;
+ __bkey_put(b->c, &b->key);
+
+ bch_journal_meta(b->c, NULL);
+ pr_debug("%s for %pf", pbtree(b), __builtin_return_address(0));
+}
+
+/* Cache lookup */
+
+static int submit_partial_cache_miss(struct btree *b, struct btree_op *op,
+ struct bkey *k)
+{
+ struct search *s = container_of(op, struct search, op);
+ struct bio *bio = &s->bio.bio;
+ int ret = 0;
+
+ while (!ret &&
+ !op->lookup_done) {
+ unsigned sectors = INT_MAX;
+
+ if (KEY_INODE(k) == op->inode) {
+ if (KEY_START(k) <= bio->bi_sector)
+ break;
+
+ sectors = min_t(uint64_t, sectors,
+ KEY_START(k) - bio->bi_sector);
+ }
+
+ ret = s->d->cache_miss(b, s, bio, sectors);
+ }
+
+ return ret;
+}
+
+/*
+ * Read from a single key, handling the initial cache miss if the key starts in
+ * the middle of the bio
+ */
+static int submit_partial_cache_hit(struct btree *b, struct btree_op *op,
+ struct bkey *k)
+{
+ struct search *s = container_of(op, struct search, op);
+ struct bio *bio = &s->bio.bio;
+ unsigned ptr;
+ struct bio *n;
+
+ int ret = submit_partial_cache_miss(b, op, k);
+ if (ret || op->lookup_done)
+ return ret;
+
+ /* XXX: figure out best pointer - for multiple cache devices */
+ ptr = 0;
+
+ PTR_BUCKET(b->c, k, ptr)->prio = INITIAL_PRIO;
+
+ while (!op->lookup_done &&
+ KEY_INODE(k) == op->inode &&
+ bio->bi_sector < KEY_OFFSET(k)) {
+ struct bkey *bio_key;
+ sector_t sector = PTR_OFFSET(k, ptr) +
+ (bio->bi_sector - KEY_START(k));
+ unsigned sectors = min_t(uint64_t, INT_MAX,
+ KEY_OFFSET(k) - bio->bi_sector);
+
+ n = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
+ if (!n)
+ return -EAGAIN;
+
+ if (n == bio)
+ op->lookup_done = true;
+
+ bio_key = &container_of(n, struct bbio, bio)->key;
+
+ /*
+ * The bucket we're reading from might be reused while our bio
+ * is in flight, and we could then end up reading the wrong
+ * data.
+ *
+ * We guard against this by checking (in cache_read_endio()) if
+ * the pointer is stale again; if so, we treat it as an error
+ * and reread from the backing device (but we don't pass that
+ * error up anywhere).
+ */
+
+ bch_bkey_copy_single_ptr(bio_key, k, ptr);
+ SET_PTR_OFFSET(bio_key, 0, sector);
+
+ n->bi_end_io = bch_cache_read_endio;
+ n->bi_private = &s->cl;
+
+ trace_bcache_cache_hit(n);
+ __bch_submit_bbio(n, b->c);
+ }
+
+ return 0;
+}
+
+int bch_btree_search_recurse(struct btree *b, struct btree_op *op)
+{
+ struct search *s = container_of(op, struct search, op);
+ struct bio *bio = &s->bio.bio;
+
+ int ret = 0;
+ struct bkey *k;
+ struct btree_iter iter;
+ bch_btree_iter_init(b, &iter, &KEY(op->inode, bio->bi_sector, 0));
+
+ pr_debug("at %s searching for %u:%llu", pbtree(b), op->inode,
+ (uint64_t) bio->bi_sector);
+
+ do {
+ k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
+ if (!k) {
+ /*
+ * b->key would be exactly what we want, except that
+ * pointers to btree nodes have nonzero size - we
+ * wouldn't go far enough
+ */
+
+ ret = submit_partial_cache_miss(b, op,
+ &KEY(KEY_INODE(&b->key),
+ KEY_OFFSET(&b->key), 0));
+ break;
+ }
+
+ ret = b->level
+ ? btree(search_recurse, k, b, op)
+ : submit_partial_cache_hit(b, op, k);
+ } while (!ret &&
+ !op->lookup_done);
+
+ return ret;
+}
+
+/* Keybuf code */
+
+static inline int keybuf_cmp(struct keybuf_key *l, struct keybuf_key *r)
+{
+ /* Overlapping keys compare equal */
+ if (bkey_cmp(&l->key, &START_KEY(&r->key)) <= 0)
+ return -1;
+ if (bkey_cmp(&START_KEY(&l->key), &r->key) >= 0)
+ return 1;
+ return 0;
+}
+
+static inline int keybuf_nonoverlapping_cmp(struct keybuf_key *l,
+ struct keybuf_key *r)
+{
+ return clamp_t(int64_t, bkey_cmp(&l->key, &r->key), -1, 1);
+}
+
+static int bch_btree_refill_keybuf(struct btree *b, struct btree_op *op,
+ struct keybuf *buf, struct bkey *end)
+{
+ struct btree_iter iter;
+ bch_btree_iter_init(b, &iter, &buf->last_scanned);
+
+ while (!array_freelist_empty(&buf->freelist)) {
+ struct bkey *k = bch_btree_iter_next_filter(&iter, b,
+ bch_ptr_bad);
+
+ if (!b->level) {
+ if (!k) {
+ buf->last_scanned = b->key;
+ break;
+ }
+
+ buf->last_scanned = *k;
+ if (bkey_cmp(&buf->last_scanned, end) >= 0)
+ break;
+
+ if (buf->key_predicate(buf, k)) {
+ struct keybuf_key *w;
+
+ pr_debug("%s", pkey(k));
+
+ spin_lock(&buf->lock);
+
+ w = array_alloc(&buf->freelist);
+
+ w->private = NULL;
+ bkey_copy(&w->key, k);
+
+ if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
+ array_free(&buf->freelist, w);
+
+ spin_unlock(&buf->lock);
+ }
+ } else {
+ if (!k)
+ break;
+
+ btree(refill_keybuf, k, b, op, buf, end);
+ /*
+ * Might get an error here, but can't really do anything
+ * and it'll get logged elsewhere. Just read what we
+ * can.
+ */
+
+ if (bkey_cmp(&buf->last_scanned, end) >= 0)
+ break;
+
+ cond_resched();
+ }
+ }
+
+ return 0;
+}
+
+void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
+ struct bkey *end)
+{
+ struct bkey start = buf->last_scanned;
+ struct btree_op op;
+ bch_btree_op_init_stack(&op);
+
+ cond_resched();
+
+ btree_root(refill_keybuf, c, &op, buf, end);
+ closure_sync(&op.cl);
+
+ pr_debug("found %s keys from %llu:%llu to %llu:%llu",
+ RB_EMPTY_ROOT(&buf->keys) ? "no" :
+ array_freelist_empty(&buf->freelist) ? "some" : "a few",
+ KEY_INODE(&start), KEY_OFFSET(&start),
+ KEY_INODE(&buf->last_scanned), KEY_OFFSET(&buf->last_scanned));
+
+ spin_lock(&buf->lock);
+
+ if (!RB_EMPTY_ROOT(&buf->keys)) {
+ struct keybuf_key *w;
+ w = RB_FIRST(&buf->keys, struct keybuf_key, node);
+ buf->start = START_KEY(&w->key);
+
+ w = RB_LAST(&buf->keys, struct keybuf_key, node);
+ buf->end = w->key;
+ } else {
+ buf->start = MAX_KEY;
+ buf->end = MAX_KEY;
+ }
+
+ spin_unlock(&buf->lock);
+}
+
+static void __bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
+{
+ rb_erase(&w->node, &buf->keys);
+ array_free(&buf->freelist, w);
+}
+
+void bch_keybuf_del(struct keybuf *buf, struct keybuf_key *w)
+{
+ spin_lock(&buf->lock);
+ __bch_keybuf_del(buf, w);
+ spin_unlock(&buf->lock);
+}
+
+bool bch_keybuf_check_overlapping(struct keybuf *buf, struct bkey *start,
+ struct bkey *end)
+{
+ bool ret = false;
+ struct keybuf_key *p, *w, s;
+ s.key = *start;
+
+ if (bkey_cmp(end, &buf->start) <= 0 ||
+ bkey_cmp(start, &buf->end) >= 0)
+ return false;
+
+ spin_lock(&buf->lock);
+ w = RB_GREATER(&buf->keys, s, node, keybuf_nonoverlapping_cmp);
+
+ while (w && bkey_cmp(&START_KEY(&w->key), end) < 0) {
+ p = w;
+ w = RB_NEXT(w, node);
+
+ if (p->private)
+ ret = true;
+ else
+ __bch_keybuf_del(buf, p);
+ }
+
+ spin_unlock(&buf->lock);
+ return ret;
+}
+
+struct keybuf_key *bch_keybuf_next(struct keybuf *buf)
+{
+ struct keybuf_key *w;
+ spin_lock(&buf->lock);
+
+ w = RB_FIRST(&buf->keys, struct keybuf_key, node);
+
+ while (w && w->private)
+ w = RB_NEXT(w, node);
+
+ if (w)
+ w->private = ERR_PTR(-EINTR);
+
+ spin_unlock(&buf->lock);
+ return w;
+}
+
+struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *c,
+ struct keybuf *buf,
+ struct bkey *end)
+{
+ struct keybuf_key *ret;
+
+ while (1) {
+ ret = bch_keybuf_next(buf);
+ if (ret)
+ break;
+
+ if (bkey_cmp(&buf->last_scanned, end) >= 0) {
+ pr_debug("scan finished");
+ break;
+ }
+
+ bch_refill_keybuf(c, buf, end);
+ }
+
+ return ret;
+}
+
+void bch_keybuf_init(struct keybuf *buf, keybuf_pred_fn *fn)
+{
+ buf->key_predicate = fn;
+ buf->last_scanned = MAX_KEY;
+ buf->keys = RB_ROOT;
+
+ spin_lock_init(&buf->lock);
+ array_allocator_init(&buf->freelist);
+}
+
+void bch_btree_exit(void)
+{
+ if (btree_io_wq)
+ destroy_workqueue(btree_io_wq);
+ if (bch_gc_wq)
+ destroy_workqueue(bch_gc_wq);
+}
+
+int __init bch_btree_init(void)
+{
+ if (!(bch_gc_wq = create_singlethread_workqueue("bch_btree_gc")) ||
+ !(btree_io_wq = create_singlethread_workqueue("bch_btree_io")))
+ return -ENOMEM;
+
+ return 0;
+}
--- /dev/null
+#ifndef _BCACHE_BTREE_H
+#define _BCACHE_BTREE_H
+
+/*
+ * THE BTREE:
+ *
+ * At a high level, bcache's btree is relatively standard b+ tree. All keys and
+ * pointers are in the leaves; interior nodes only have pointers to the child
+ * nodes.
+ *
+ * In the interior nodes, a struct bkey always points to a child btree node, and
+ * the key is the highest key in the child node - except that the highest key in
+ * an interior node is always MAX_KEY. The size field refers to the size on disk
+ * of the child node - this would allow us to have variable sized btree nodes
+ * (handy for keeping the depth of the btree 1 by expanding just the root).
+ *
+ * Btree nodes are themselves log structured, but this is hidden fairly
+ * thoroughly. Btree nodes on disk will in practice have extents that overlap
+ * (because they were written at different times), but in memory we never have
+ * overlapping extents - when we read in a btree node from disk, the first thing
+ * we do is resort all the sets of keys with a mergesort, and in the same pass
+ * we check for overlapping extents and adjust them appropriately.
+ *
+ * struct btree_op is a central interface to the btree code. It's used for
+ * specifying read vs. write locking, and the embedded closure is used for
+ * waiting on IO or reserve memory.
+ *
+ * BTREE CACHE:
+ *
+ * Btree nodes are cached in memory; traversing the btree might require reading
+ * in btree nodes which is handled mostly transparently.
+ *
+ * bch_btree_node_get() looks up a btree node in the cache and reads it in from
+ * disk if necessary. This function is almost never called directly though - the
+ * btree() macro is used to get a btree node, call some function on it, and
+ * unlock the node after the function returns.
+ *
+ * The root is special cased - it's taken out of the cache's lru (thus pinning
+ * it in memory), so we can find the root of the btree by just dereferencing a
+ * pointer instead of looking it up in the cache. This makes locking a bit
+ * tricky, since the root pointer is protected by the lock in the btree node it
+ * points to - the btree_root() macro handles this.
+ *
+ * In various places we must be able to allocate memory for multiple btree nodes
+ * in order to make forward progress. To do this we use the btree cache itself
+ * as a reserve; if __get_free_pages() fails, we'll find a node in the btree
+ * cache we can reuse. We can't allow more than one thread to be doing this at a
+ * time, so there's a lock, implemented by a pointer to the btree_op closure -
+ * this allows the btree_root() macro to implicitly release this lock.
+ *
+ * BTREE IO:
+ *
+ * Btree nodes never have to be explicitly read in; bch_btree_node_get() handles
+ * this.
+ *
+ * For writing, we have two btree_write structs embeddded in struct btree - one
+ * write in flight, and one being set up, and we toggle between them.
+ *
+ * Writing is done with a single function - bch_btree_write() really serves two
+ * different purposes and should be broken up into two different functions. When
+ * passing now = false, it merely indicates that the node is now dirty - calling
+ * it ensures that the dirty keys will be written at some point in the future.
+ *
+ * When passing now = true, bch_btree_write() causes a write to happen
+ * "immediately" (if there was already a write in flight, it'll cause the write
+ * to happen as soon as the previous write completes). It returns immediately
+ * though - but it takes a refcount on the closure in struct btree_op you passed
+ * to it, so a closure_sync() later can be used to wait for the write to
+ * complete.
+ *
+ * This is handy because btree_split() and garbage collection can issue writes
+ * in parallel, reducing the amount of time they have to hold write locks.
+ *
+ * LOCKING:
+ *
+ * When traversing the btree, we may need write locks starting at some level -
+ * inserting a key into the btree will typically only require a write lock on
+ * the leaf node.
+ *
+ * This is specified with the lock field in struct btree_op; lock = 0 means we
+ * take write locks at level <= 0, i.e. only leaf nodes. bch_btree_node_get()
+ * checks this field and returns the node with the appropriate lock held.
+ *
+ * If, after traversing the btree, the insertion code discovers it has to split
+ * then it must restart from the root and take new locks - to do this it changes
+ * the lock field and returns -EINTR, which causes the btree_root() macro to
+ * loop.
+ *
+ * Handling cache misses require a different mechanism for upgrading to a write
+ * lock. We do cache lookups with only a read lock held, but if we get a cache
+ * miss and we wish to insert this data into the cache, we have to insert a
+ * placeholder key to detect races - otherwise, we could race with a write and
+ * overwrite the data that was just written to the cache with stale data from
+ * the backing device.
+ *
+ * For this we use a sequence number that write locks and unlocks increment - to
+ * insert the check key it unlocks the btree node and then takes a write lock,
+ * and fails if the sequence number doesn't match.
+ */
+
+#include "bset.h"
+#include "debug.h"
+
+struct btree_write {
+ struct closure *owner;
+ atomic_t *journal;
+
+ /* If btree_split() frees a btree node, it writes a new pointer to that
+ * btree node indicating it was freed; it takes a refcount on
+ * c->prio_blocked because we can't write the gens until the new
+ * pointer is on disk. This allows btree_write_endio() to release the
+ * refcount that btree_split() took.
+ */
+ int prio_blocked;
+};
+
+struct btree {
+ /* Hottest entries first */
+ struct hlist_node hash;
+
+ /* Key/pointer for this btree node */
+ BKEY_PADDED(key);
+
+ /* Single bit - set when accessed, cleared by shrinker */
+ unsigned long accessed;
+ unsigned long seq;
+ struct rw_semaphore lock;
+ struct cache_set *c;
+
+ unsigned long flags;
+ uint16_t written; /* would be nice to kill */
+ uint8_t level;
+ uint8_t nsets;
+ uint8_t page_order;
+
+ /*
+ * Set of sorted keys - the real btree node - plus a binary search tree
+ *
+ * sets[0] is special; set[0]->tree, set[0]->prev and set[0]->data point
+ * to the memory we have allocated for this btree node. Additionally,
+ * set[0]->data points to the entire btree node as it exists on disk.
+ */
+ struct bset_tree sets[MAX_BSETS];
+
+ /* Used to refcount bio splits, also protects b->bio */
+ struct closure_with_waitlist io;
+
+ /* Gets transferred to w->prio_blocked - see the comment there */
+ int prio_blocked;
+
+ struct list_head list;
+ struct delayed_work work;
+
+ uint64_t io_start_time;
+ struct btree_write writes[2];
+ struct bio *bio;
+};
+
+#define BTREE_FLAG(flag) \
+static inline bool btree_node_ ## flag(struct btree *b) \
+{ return test_bit(BTREE_NODE_ ## flag, &b->flags); } \
+ \
+static inline void set_btree_node_ ## flag(struct btree *b) \
+{ set_bit(BTREE_NODE_ ## flag, &b->flags); } \
+
+enum btree_flags {
+ BTREE_NODE_read_done,
+ BTREE_NODE_io_error,
+ BTREE_NODE_dirty,
+ BTREE_NODE_write_idx,
+};
+
+BTREE_FLAG(read_done);
+BTREE_FLAG(io_error);
+BTREE_FLAG(dirty);
+BTREE_FLAG(write_idx);
+
+static inline struct btree_write *btree_current_write(struct btree *b)
+{
+ return b->writes + btree_node_write_idx(b);
+}
+
+static inline struct btree_write *btree_prev_write(struct btree *b)
+{
+ return b->writes + (btree_node_write_idx(b) ^ 1);
+}
+
+static inline unsigned bset_offset(struct btree *b, struct bset *i)
+{
+ return (((size_t) i) - ((size_t) b->sets->data)) >> 9;
+}
+
+static inline struct bset *write_block(struct btree *b)
+{
+ return ((void *) b->sets[0].data) + b->written * block_bytes(b->c);
+}
+
+static inline bool bset_written(struct btree *b, struct bset_tree *t)
+{
+ return t->data < write_block(b);
+}
+
+static inline bool bkey_written(struct btree *b, struct bkey *k)
+{
+ return k < write_block(b)->start;
+}
+
+static inline void set_gc_sectors(struct cache_set *c)
+{
+ atomic_set(&c->sectors_to_gc, c->sb.bucket_size * c->nbuckets / 8);
+}
+
+static inline bool bch_ptr_invalid(struct btree *b, const struct bkey *k)
+{
+ return __bch_ptr_invalid(b->c, b->level, k);
+}
+
+static inline struct bkey *bch_btree_iter_init(struct btree *b,
+ struct btree_iter *iter,
+ struct bkey *search)
+{
+ return __bch_btree_iter_init(b, iter, search, b->sets);
+}
+
+/* Looping macros */
+
+#define for_each_cached_btree(b, c, iter) \
+ for (iter = 0; \
+ iter < ARRAY_SIZE((c)->bucket_hash); \
+ iter++) \
+ hlist_for_each_entry_rcu((b), (c)->bucket_hash + iter, hash)
+
+#define for_each_key_filter(b, k, iter, filter) \
+ for (bch_btree_iter_init((b), (iter), NULL); \
+ ((k) = bch_btree_iter_next_filter((iter), b, filter));)
+
+#define for_each_key(b, k, iter) \
+ for (bch_btree_iter_init((b), (iter), NULL); \
+ ((k) = bch_btree_iter_next(iter));)
+
+/* Recursing down the btree */
+
+struct btree_op {
+ struct closure cl;
+ struct cache_set *c;
+
+ /* Journal entry we have a refcount on */
+ atomic_t *journal;
+
+ /* Bio to be inserted into the cache */
+ struct bio *cache_bio;
+
+ unsigned inode;
+
+ uint16_t write_prio;
+
+ /* Btree level at which we start taking write locks */
+ short lock;
+
+ /* Btree insertion type */
+ enum {
+ BTREE_INSERT,
+ BTREE_REPLACE
+ } type:8;
+
+ unsigned csum:1;
+ unsigned skip:1;
+ unsigned flush_journal:1;
+
+ unsigned insert_data_done:1;
+ unsigned lookup_done:1;
+ unsigned insert_collision:1;
+
+ /* Anything after this point won't get zeroed in do_bio_hook() */
+
+ /* Keys to be inserted */
+ struct keylist keys;
+ BKEY_PADDED(replace);
+};
+
+void bch_btree_op_init_stack(struct btree_op *);
+
+static inline void rw_lock(bool w, struct btree *b, int level)
+{
+ w ? down_write_nested(&b->lock, level + 1)
+ : down_read_nested(&b->lock, level + 1);
+ if (w)
+ b->seq++;
+}
+
+static inline void rw_unlock(bool w, struct btree *b)
+{
+#ifdef CONFIG_BCACHE_EDEBUG
+ unsigned i;
+
+ if (w &&
+ b->key.ptr[0] &&
+ btree_node_read_done(b))
+ for (i = 0; i <= b->nsets; i++)
+ bch_check_key_order(b, b->sets[i].data);
+#endif
+
+ if (w)
+ b->seq++;
+ (w ? up_write : up_read)(&b->lock);
+}
+
+#define insert_lock(s, b) ((b)->level <= (s)->lock)
+
+/*
+ * These macros are for recursing down the btree - they handle the details of
+ * locking and looking up nodes in the cache for you. They're best treated as
+ * mere syntax when reading code that uses them.
+ *
+ * op->lock determines whether we take a read or a write lock at a given depth.
+ * If you've got a read lock and find that you need a write lock (i.e. you're
+ * going to have to split), set op->lock and return -EINTR; btree_root() will
+ * call you again and you'll have the correct lock.
+ */
+
+/**
+ * btree - recurse down the btree on a specified key
+ * @fn: function to call, which will be passed the child node
+ * @key: key to recurse on
+ * @b: parent btree node
+ * @op: pointer to struct btree_op
+ */
+#define btree(fn, key, b, op, ...) \
+({ \
+ int _r, l = (b)->level - 1; \
+ bool _w = l <= (op)->lock; \
+ struct btree *_b = bch_btree_node_get((b)->c, key, l, op); \
+ if (!IS_ERR(_b)) { \
+ _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
+ rw_unlock(_w, _b); \
+ } else \
+ _r = PTR_ERR(_b); \
+ _r; \
+})
+
+/**
+ * btree_root - call a function on the root of the btree
+ * @fn: function to call, which will be passed the child node
+ * @c: cache set
+ * @op: pointer to struct btree_op
+ */
+#define btree_root(fn, c, op, ...) \
+({ \
+ int _r = -EINTR; \
+ do { \
+ struct btree *_b = (c)->root; \
+ bool _w = insert_lock(op, _b); \
+ rw_lock(_w, _b, _b->level); \
+ if (_b == (c)->root && \
+ _w == insert_lock(op, _b)) \
+ _r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
+ rw_unlock(_w, _b); \
+ bch_cannibalize_unlock(c, &(op)->cl); \
+ } while (_r == -EINTR); \
+ \
+ _r; \
+})
+
+static inline bool should_split(struct btree *b)
+{
+ struct bset *i = write_block(b);
+ return b->written >= btree_blocks(b) ||
+ (i->seq == b->sets[0].data->seq &&
+ b->written + __set_blocks(i, i->keys + 15, b->c)
+ > btree_blocks(b));
+}
+
+void bch_btree_read_done(struct closure *);
+void bch_btree_read(struct btree *);
+void bch_btree_write(struct btree *b, bool now, struct btree_op *op);
+
+void bch_cannibalize_unlock(struct cache_set *, struct closure *);
+void bch_btree_set_root(struct btree *);
+struct btree *bch_btree_node_alloc(struct cache_set *, int, struct closure *);
+struct btree *bch_btree_node_get(struct cache_set *, struct bkey *,
+ int, struct btree_op *);
+
+bool bch_btree_insert_keys(struct btree *, struct btree_op *);
+bool bch_btree_insert_check_key(struct btree *, struct btree_op *,
+ struct bio *);
+int bch_btree_insert(struct btree_op *, struct cache_set *);
+
+int bch_btree_search_recurse(struct btree *, struct btree_op *);
+
+void bch_queue_gc(struct cache_set *);
+size_t bch_btree_gc_finish(struct cache_set *);
+void bch_moving_gc(struct closure *);
+int bch_btree_check(struct cache_set *, struct btree_op *);
+uint8_t __bch_btree_mark_key(struct cache_set *, int, struct bkey *);
+
+void bch_keybuf_init(struct keybuf *, keybuf_pred_fn *);
+void bch_refill_keybuf(struct cache_set *, struct keybuf *, struct bkey *);
+bool bch_keybuf_check_overlapping(struct keybuf *, struct bkey *,
+ struct bkey *);
+void bch_keybuf_del(struct keybuf *, struct keybuf_key *);
+struct keybuf_key *bch_keybuf_next(struct keybuf *);
+struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *,
+ struct keybuf *, struct bkey *);
+
+#endif
--- /dev/null
+/*
+ * Asynchronous refcounty things
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+
+#include "closure.h"
+
+void closure_queue(struct closure *cl)
+{
+ struct workqueue_struct *wq = cl->wq;
+ if (wq) {
+ INIT_WORK(&cl->work, cl->work.func);
+ BUG_ON(!queue_work(wq, &cl->work));
+ } else
+ cl->fn(cl);
+}
+EXPORT_SYMBOL_GPL(closure_queue);
+
+#define CL_FIELD(type, field) \
+ case TYPE_ ## type: \
+ return &container_of(cl, struct type, cl)->field
+
+static struct closure_waitlist *closure_waitlist(struct closure *cl)
+{
+ switch (cl->type) {
+ CL_FIELD(closure_with_waitlist, wait);
+ CL_FIELD(closure_with_waitlist_and_timer, wait);
+ default:
+ return NULL;
+ }
+}
+
+static struct timer_list *closure_timer(struct closure *cl)
+{
+ switch (cl->type) {
+ CL_FIELD(closure_with_timer, timer);
+ CL_FIELD(closure_with_waitlist_and_timer, timer);
+ default:
+ return NULL;
+ }
+}
+
+static inline void closure_put_after_sub(struct closure *cl, int flags)
+{
+ int r = flags & CLOSURE_REMAINING_MASK;
+
+ BUG_ON(flags & CLOSURE_GUARD_MASK);
+ BUG_ON(!r && (flags & ~(CLOSURE_DESTRUCTOR|CLOSURE_BLOCKING)));
+
+ /* Must deliver precisely one wakeup */
+ if (r == 1 && (flags & CLOSURE_SLEEPING))
+ wake_up_process(cl->task);
+
+ if (!r) {
+ if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
+ /* CLOSURE_BLOCKING might be set - clear it */
+ atomic_set(&cl->remaining,
+ CLOSURE_REMAINING_INITIALIZER);
+ closure_queue(cl);
+ } else {
+ struct closure *parent = cl->parent;
+ struct closure_waitlist *wait = closure_waitlist(cl);
+
+ closure_debug_destroy(cl);
+
+ atomic_set(&cl->remaining, -1);
+
+ if (wait)
+ closure_wake_up(wait);
+
+ if (cl->fn)
+ cl->fn(cl);
+
+ if (parent)
+ closure_put(parent);
+ }
+ }
+}
+
+/* For clearing flags with the same atomic op as a put */
+void closure_sub(struct closure *cl, int v)
+{
+ closure_put_after_sub(cl, atomic_sub_return(v, &cl->remaining));
+}
+EXPORT_SYMBOL_GPL(closure_sub);
+
+void closure_put(struct closure *cl)
+{
+ closure_put_after_sub(cl, atomic_dec_return(&cl->remaining));
+}
+EXPORT_SYMBOL_GPL(closure_put);
+
+static void set_waiting(struct closure *cl, unsigned long f)
+{
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+ cl->waiting_on = f;
+#endif
+}
+
+void __closure_wake_up(struct closure_waitlist *wait_list)
+{
+ struct llist_node *list;
+ struct closure *cl;
+ struct llist_node *reverse = NULL;
+
+ list = llist_del_all(&wait_list->list);
+
+ /* We first reverse the list to preserve FIFO ordering and fairness */
+
+ while (list) {
+ struct llist_node *t = list;
+ list = llist_next(list);
+
+ t->next = reverse;
+ reverse = t;
+ }
+
+ /* Then do the wakeups */
+
+ while (reverse) {
+ cl = container_of(reverse, struct closure, list);
+ reverse = llist_next(reverse);
+
+ set_waiting(cl, 0);
+ closure_sub(cl, CLOSURE_WAITING + 1);
+ }
+}
+EXPORT_SYMBOL_GPL(__closure_wake_up);
+
+bool closure_wait(struct closure_waitlist *list, struct closure *cl)
+{
+ if (atomic_read(&cl->remaining) & CLOSURE_WAITING)
+ return false;
+
+ set_waiting(cl, _RET_IP_);
+ atomic_add(CLOSURE_WAITING + 1, &cl->remaining);
+ llist_add(&cl->list, &list->list);
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(closure_wait);
+
+/**
+ * closure_sync() - sleep until a closure a closure has nothing left to wait on
+ *
+ * Sleeps until the refcount hits 1 - the thread that's running the closure owns
+ * the last refcount.
+ */
+void closure_sync(struct closure *cl)
+{
+ while (1) {
+ __closure_start_sleep(cl);
+ closure_set_ret_ip(cl);
+
+ if ((atomic_read(&cl->remaining) &
+ CLOSURE_REMAINING_MASK) == 1)
+ break;
+
+ schedule();
+ }
+
+ __closure_end_sleep(cl);
+}
+EXPORT_SYMBOL_GPL(closure_sync);
+
+/**
+ * closure_trylock() - try to acquire the closure, without waiting
+ * @cl: closure to lock
+ *
+ * Returns true if the closure was succesfully locked.
+ */
+bool closure_trylock(struct closure *cl, struct closure *parent)
+{
+ if (atomic_cmpxchg(&cl->remaining, -1,
+ CLOSURE_REMAINING_INITIALIZER) != -1)
+ return false;
+
+ closure_set_ret_ip(cl);
+
+ smp_mb();
+ cl->parent = parent;
+ if (parent)
+ closure_get(parent);
+
+ closure_debug_create(cl);
+ return true;
+}
+EXPORT_SYMBOL_GPL(closure_trylock);
+
+void __closure_lock(struct closure *cl, struct closure *parent,
+ struct closure_waitlist *wait_list)
+{
+ struct closure wait;
+ closure_init_stack(&wait);
+
+ while (1) {
+ if (closure_trylock(cl, parent))
+ return;
+
+ closure_wait_event_sync(wait_list, &wait,
+ atomic_read(&cl->remaining) == -1);
+ }
+}
+EXPORT_SYMBOL_GPL(__closure_lock);
+
+static void closure_delay_timer_fn(unsigned long data)
+{
+ struct closure *cl = (struct closure *) data;
+ closure_sub(cl, CLOSURE_TIMER + 1);
+}
+
+void do_closure_timer_init(struct closure *cl)
+{
+ struct timer_list *timer = closure_timer(cl);
+
+ init_timer(timer);
+ timer->data = (unsigned long) cl;
+ timer->function = closure_delay_timer_fn;
+}
+EXPORT_SYMBOL_GPL(do_closure_timer_init);
+
+bool __closure_delay(struct closure *cl, unsigned long delay,
+ struct timer_list *timer)
+{
+ if (atomic_read(&cl->remaining) & CLOSURE_TIMER)
+ return false;
+
+ BUG_ON(timer_pending(timer));
+
+ timer->expires = jiffies + delay;
+
+ atomic_add(CLOSURE_TIMER + 1, &cl->remaining);
+ add_timer(timer);
+ return true;
+}
+EXPORT_SYMBOL_GPL(__closure_delay);
+
+void __closure_flush(struct closure *cl, struct timer_list *timer)
+{
+ if (del_timer(timer))
+ closure_sub(cl, CLOSURE_TIMER + 1);
+}
+EXPORT_SYMBOL_GPL(__closure_flush);
+
+void __closure_flush_sync(struct closure *cl, struct timer_list *timer)
+{
+ if (del_timer_sync(timer))
+ closure_sub(cl, CLOSURE_TIMER + 1);
+}
+EXPORT_SYMBOL_GPL(__closure_flush_sync);
+
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+
+static LIST_HEAD(closure_list);
+static DEFINE_SPINLOCK(closure_list_lock);
+
+void closure_debug_create(struct closure *cl)
+{
+ unsigned long flags;
+
+ BUG_ON(cl->magic == CLOSURE_MAGIC_ALIVE);
+ cl->magic = CLOSURE_MAGIC_ALIVE;
+
+ spin_lock_irqsave(&closure_list_lock, flags);
+ list_add(&cl->all, &closure_list);
+ spin_unlock_irqrestore(&closure_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(closure_debug_create);
+
+void closure_debug_destroy(struct closure *cl)
+{
+ unsigned long flags;
+
+ BUG_ON(cl->magic != CLOSURE_MAGIC_ALIVE);
+ cl->magic = CLOSURE_MAGIC_DEAD;
+
+ spin_lock_irqsave(&closure_list_lock, flags);
+ list_del(&cl->all);
+ spin_unlock_irqrestore(&closure_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(closure_debug_destroy);
+
+static struct dentry *debug;
+
+#define work_data_bits(work) ((unsigned long *)(&(work)->data))
+
+static int debug_seq_show(struct seq_file *f, void *data)
+{
+ struct closure *cl;
+ spin_lock_irq(&closure_list_lock);
+
+ list_for_each_entry(cl, &closure_list, all) {
+ int r = atomic_read(&cl->remaining);
+
+ seq_printf(f, "%p: %pF -> %pf p %p r %i ",
+ cl, (void *) cl->ip, cl->fn, cl->parent,
+ r & CLOSURE_REMAINING_MASK);
+
+ seq_printf(f, "%s%s%s%s%s%s\n",
+ test_bit(WORK_STRUCT_PENDING,
+ work_data_bits(&cl->work)) ? "Q" : "",
+ r & CLOSURE_RUNNING ? "R" : "",
+ r & CLOSURE_BLOCKING ? "B" : "",
+ r & CLOSURE_STACK ? "S" : "",
+ r & CLOSURE_SLEEPING ? "Sl" : "",
+ r & CLOSURE_TIMER ? "T" : "");
+
+ if (r & CLOSURE_WAITING)
+ seq_printf(f, " W %pF\n",
+ (void *) cl->waiting_on);
+
+ seq_printf(f, "\n");
+ }
+
+ spin_unlock_irq(&closure_list_lock);
+ return 0;
+}
+
+static int debug_seq_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, debug_seq_show, NULL);
+}
+
+static const struct file_operations debug_ops = {
+ .owner = THIS_MODULE,
+ .open = debug_seq_open,
+ .read = seq_read,
+ .release = single_release
+};
+
+int __init closure_debug_init(void)
+{
+ debug = debugfs_create_file("closures", 0400, NULL, NULL, &debug_ops);
+ return 0;
+}
+
+module_init(closure_debug_init);
+
+#endif
+
+MODULE_AUTHOR("Kent Overstreet <koverstreet@google.com>");
+MODULE_LICENSE("GPL");
--- /dev/null
+#ifndef _LINUX_CLOSURE_H
+#define _LINUX_CLOSURE_H
+
+#include <linux/llist.h>
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+
+/*
+ * Closure is perhaps the most overused and abused term in computer science, but
+ * since I've been unable to come up with anything better you're stuck with it
+ * again.
+ *
+ * What are closures?
+ *
+ * They embed a refcount. The basic idea is they count "things that are in
+ * progress" - in flight bios, some other thread that's doing something else -
+ * anything you might want to wait on.
+ *
+ * The refcount may be manipulated with closure_get() and closure_put().
+ * closure_put() is where many of the interesting things happen, when it causes
+ * the refcount to go to 0.
+ *
+ * Closures can be used to wait on things both synchronously and asynchronously,
+ * and synchronous and asynchronous use can be mixed without restriction. To
+ * wait synchronously, use closure_sync() - you will sleep until your closure's
+ * refcount hits 1.
+ *
+ * To wait asynchronously, use
+ * continue_at(cl, next_function, workqueue);
+ *
+ * passing it, as you might expect, the function to run when nothing is pending
+ * and the workqueue to run that function out of.
+ *
+ * continue_at() also, critically, is a macro that returns the calling function.
+ * There's good reason for this.
+ *
+ * To use safely closures asynchronously, they must always have a refcount while
+ * they are running owned by the thread that is running them. Otherwise, suppose
+ * you submit some bios and wish to have a function run when they all complete:
+ *
+ * foo_endio(struct bio *bio, int error)
+ * {
+ * closure_put(cl);
+ * }
+ *
+ * closure_init(cl);
+ *
+ * do_stuff();
+ * closure_get(cl);
+ * bio1->bi_endio = foo_endio;
+ * bio_submit(bio1);
+ *
+ * do_more_stuff();
+ * closure_get(cl);
+ * bio2->bi_endio = foo_endio;
+ * bio_submit(bio2);
+ *
+ * continue_at(cl, complete_some_read, system_wq);
+ *
+ * If closure's refcount started at 0, complete_some_read() could run before the
+ * second bio was submitted - which is almost always not what you want! More
+ * importantly, it wouldn't be possible to say whether the original thread or
+ * complete_some_read()'s thread owned the closure - and whatever state it was
+ * associated with!
+ *
+ * So, closure_init() initializes a closure's refcount to 1 - and when a
+ * closure_fn is run, the refcount will be reset to 1 first.
+ *
+ * Then, the rule is - if you got the refcount with closure_get(), release it
+ * with closure_put() (i.e, in a bio->bi_endio function). If you have a refcount
+ * on a closure because you called closure_init() or you were run out of a
+ * closure - _always_ use continue_at(). Doing so consistently will help
+ * eliminate an entire class of particularly pernicious races.
+ *
+ * For a closure to wait on an arbitrary event, we need to introduce waitlists:
+ *
+ * struct closure_waitlist list;
+ * closure_wait_event(list, cl, condition);
+ * closure_wake_up(wait_list);
+ *
+ * These work analagously to wait_event() and wake_up() - except that instead of
+ * operating on the current thread (for wait_event()) and lists of threads, they
+ * operate on an explicit closure and lists of closures.
+ *
+ * Because it's a closure we can now wait either synchronously or
+ * asynchronously. closure_wait_event() returns the current value of the
+ * condition, and if it returned false continue_at() or closure_sync() can be
+ * used to wait for it to become true.
+ *
+ * It's useful for waiting on things when you can't sleep in the context in
+ * which you must check the condition (perhaps a spinlock held, or you might be
+ * beneath generic_make_request() - in which case you can't sleep on IO).
+ *
+ * closure_wait_event() will wait either synchronously or asynchronously,
+ * depending on whether the closure is in blocking mode or not. You can pick a
+ * mode explicitly with closure_wait_event_sync() and
+ * closure_wait_event_async(), which do just what you might expect.
+ *
+ * Lastly, you might have a wait list dedicated to a specific event, and have no
+ * need for specifying the condition - you just want to wait until someone runs
+ * closure_wake_up() on the appropriate wait list. In that case, just use
+ * closure_wait(). It will return either true or false, depending on whether the
+ * closure was already on a wait list or not - a closure can only be on one wait
+ * list at a time.
+ *
+ * Parents:
+ *
+ * closure_init() takes two arguments - it takes the closure to initialize, and
+ * a (possibly null) parent.
+ *
+ * If parent is non null, the new closure will have a refcount for its lifetime;
+ * a closure is considered to be "finished" when its refcount hits 0 and the
+ * function to run is null. Hence
+ *
+ * continue_at(cl, NULL, NULL);
+ *
+ * returns up the (spaghetti) stack of closures, precisely like normal return
+ * returns up the C stack. continue_at() with non null fn is better thought of
+ * as doing a tail call.
+ *
+ * All this implies that a closure should typically be embedded in a particular
+ * struct (which its refcount will normally control the lifetime of), and that
+ * struct can very much be thought of as a stack frame.
+ *
+ * Locking:
+ *
+ * Closures are based on work items but they can be thought of as more like
+ * threads - in that like threads and unlike work items they have a well
+ * defined lifetime; they are created (with closure_init()) and eventually
+ * complete after a continue_at(cl, NULL, NULL).
+ *
+ * Suppose you've got some larger structure with a closure embedded in it that's
+ * used for periodically doing garbage collection. You only want one garbage
+ * collection happening at a time, so the natural thing to do is protect it with
+ * a lock. However, it's difficult to use a lock protecting a closure correctly
+ * because the unlock should come after the last continue_to() (additionally, if
+ * you're using the closure asynchronously a mutex won't work since a mutex has
+ * to be unlocked by the same process that locked it).
+ *
+ * So to make it less error prone and more efficient, we also have the ability
+ * to use closures as locks:
+ *
+ * closure_init_unlocked();
+ * closure_trylock();
+ *
+ * That's all we need for trylock() - the last closure_put() implicitly unlocks
+ * it for you. But for closure_lock(), we also need a wait list:
+ *
+ * struct closure_with_waitlist frobnicator_cl;
+ *
+ * closure_init_unlocked(&frobnicator_cl);
+ * closure_lock(&frobnicator_cl);
+ *
+ * A closure_with_waitlist embeds a closure and a wait list - much like struct
+ * delayed_work embeds a work item and a timer_list. The important thing is, use
+ * it exactly like you would a regular closure and closure_put() will magically
+ * handle everything for you.
+ *
+ * We've got closures that embed timers, too. They're called, appropriately
+ * enough:
+ * struct closure_with_timer;
+ *
+ * This gives you access to closure_delay(). It takes a refcount for a specified
+ * number of jiffies - you could then call closure_sync() (for a slightly
+ * convoluted version of msleep()) or continue_at() - which gives you the same
+ * effect as using a delayed work item, except you can reuse the work_struct
+ * already embedded in struct closure.
+ *
+ * Lastly, there's struct closure_with_waitlist_and_timer. It does what you
+ * probably expect, if you happen to need the features of both. (You don't
+ * really want to know how all this is implemented, but if I've done my job
+ * right you shouldn't have to care).
+ */
+
+struct closure;
+typedef void (closure_fn) (struct closure *);
+
+struct closure_waitlist {
+ struct llist_head list;
+};
+
+enum closure_type {
+ TYPE_closure = 0,
+ TYPE_closure_with_waitlist = 1,
+ TYPE_closure_with_timer = 2,
+ TYPE_closure_with_waitlist_and_timer = 3,
+ MAX_CLOSURE_TYPE = 3,
+};
+
+enum closure_state {
+ /*
+ * CLOSURE_BLOCKING: Causes closure_wait_event() to block, instead of
+ * waiting asynchronously
+ *
+ * CLOSURE_WAITING: Set iff the closure is on a waitlist. Must be set by
+ * the thread that owns the closure, and cleared by the thread that's
+ * waking up the closure.
+ *
+ * CLOSURE_SLEEPING: Must be set before a thread uses a closure to sleep
+ * - indicates that cl->task is valid and closure_put() may wake it up.
+ * Only set or cleared by the thread that owns the closure.
+ *
+ * CLOSURE_TIMER: Analagous to CLOSURE_WAITING, indicates that a closure
+ * has an outstanding timer. Must be set by the thread that owns the
+ * closure, and cleared by the timer function when the timer goes off.
+ *
+ * The rest are for debugging and don't affect behaviour:
+ *
+ * CLOSURE_RUNNING: Set when a closure is running (i.e. by
+ * closure_init() and when closure_put() runs then next function), and
+ * must be cleared before remaining hits 0. Primarily to help guard
+ * against incorrect usage and accidentally transferring references.
+ * continue_at() and closure_return() clear it for you, if you're doing
+ * something unusual you can use closure_set_dead() which also helps
+ * annotate where references are being transferred.
+ *
+ * CLOSURE_STACK: Sanity check - remaining should never hit 0 on a
+ * closure with this flag set
+ */
+
+ CLOSURE_BITS_START = (1 << 19),
+ CLOSURE_DESTRUCTOR = (1 << 19),
+ CLOSURE_BLOCKING = (1 << 21),
+ CLOSURE_WAITING = (1 << 23),
+ CLOSURE_SLEEPING = (1 << 25),
+ CLOSURE_TIMER = (1 << 27),
+ CLOSURE_RUNNING = (1 << 29),
+ CLOSURE_STACK = (1 << 31),
+};
+
+#define CLOSURE_GUARD_MASK \
+ ((CLOSURE_DESTRUCTOR|CLOSURE_BLOCKING|CLOSURE_WAITING| \
+ CLOSURE_SLEEPING|CLOSURE_TIMER|CLOSURE_RUNNING|CLOSURE_STACK) << 1)
+
+#define CLOSURE_REMAINING_MASK (CLOSURE_BITS_START - 1)
+#define CLOSURE_REMAINING_INITIALIZER (1|CLOSURE_RUNNING)
+
+struct closure {
+ union {
+ struct {
+ struct workqueue_struct *wq;
+ struct task_struct *task;
+ struct llist_node list;
+ closure_fn *fn;
+ };
+ struct work_struct work;
+ };
+
+ struct closure *parent;
+
+ atomic_t remaining;
+
+ enum closure_type type;
+
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+#define CLOSURE_MAGIC_DEAD 0xc054dead
+#define CLOSURE_MAGIC_ALIVE 0xc054a11e
+
+ unsigned magic;
+ struct list_head all;
+ unsigned long ip;
+ unsigned long waiting_on;
+#endif
+};
+
+struct closure_with_waitlist {
+ struct closure cl;
+ struct closure_waitlist wait;
+};
+
+struct closure_with_timer {
+ struct closure cl;
+ struct timer_list timer;
+};
+
+struct closure_with_waitlist_and_timer {
+ struct closure cl;
+ struct closure_waitlist wait;
+ struct timer_list timer;
+};
+
+extern unsigned invalid_closure_type(void);
+
+#define __CLOSURE_TYPE(cl, _t) \
+ __builtin_types_compatible_p(typeof(cl), struct _t) \
+ ? TYPE_ ## _t : \
+
+#define __closure_type(cl) \
+( \
+ __CLOSURE_TYPE(cl, closure) \
+ __CLOSURE_TYPE(cl, closure_with_waitlist) \
+ __CLOSURE_TYPE(cl, closure_with_timer) \
+ __CLOSURE_TYPE(cl, closure_with_waitlist_and_timer) \
+ invalid_closure_type() \
+)
+
+void closure_sub(struct closure *cl, int v);
+void closure_put(struct closure *cl);
+void closure_queue(struct closure *cl);
+void __closure_wake_up(struct closure_waitlist *list);
+bool closure_wait(struct closure_waitlist *list, struct closure *cl);
+void closure_sync(struct closure *cl);
+
+bool closure_trylock(struct closure *cl, struct closure *parent);
+void __closure_lock(struct closure *cl, struct closure *parent,
+ struct closure_waitlist *wait_list);
+
+void do_closure_timer_init(struct closure *cl);
+bool __closure_delay(struct closure *cl, unsigned long delay,
+ struct timer_list *timer);
+void __closure_flush(struct closure *cl, struct timer_list *timer);
+void __closure_flush_sync(struct closure *cl, struct timer_list *timer);
+
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+
+void closure_debug_create(struct closure *cl);
+void closure_debug_destroy(struct closure *cl);
+
+#else
+
+static inline void closure_debug_create(struct closure *cl) {}
+static inline void closure_debug_destroy(struct closure *cl) {}
+
+#endif
+
+static inline void closure_set_ip(struct closure *cl)
+{
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+ cl->ip = _THIS_IP_;
+#endif
+}
+
+static inline void closure_set_ret_ip(struct closure *cl)
+{
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+ cl->ip = _RET_IP_;
+#endif
+}
+
+static inline void closure_get(struct closure *cl)
+{
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+ BUG_ON((atomic_inc_return(&cl->remaining) &
+ CLOSURE_REMAINING_MASK) <= 1);
+#else
+ atomic_inc(&cl->remaining);
+#endif
+}
+
+static inline void closure_set_stopped(struct closure *cl)
+{
+ atomic_sub(CLOSURE_RUNNING, &cl->remaining);
+}
+
+static inline bool closure_is_stopped(struct closure *cl)
+{
+ return !(atomic_read(&cl->remaining) & CLOSURE_RUNNING);
+}
+
+static inline bool closure_is_unlocked(struct closure *cl)
+{
+ return atomic_read(&cl->remaining) == -1;
+}
+
+static inline void do_closure_init(struct closure *cl, struct closure *parent,
+ bool running)
+{
+ switch (cl->type) {
+ case TYPE_closure_with_timer:
+ case TYPE_closure_with_waitlist_and_timer:
+ do_closure_timer_init(cl);
+ default:
+ break;
+ }
+
+ cl->parent = parent;
+ if (parent)
+ closure_get(parent);
+
+ if (running) {
+ closure_debug_create(cl);
+ atomic_set(&cl->remaining, CLOSURE_REMAINING_INITIALIZER);
+ } else
+ atomic_set(&cl->remaining, -1);
+
+ closure_set_ip(cl);
+}
+
+/*
+ * Hack to get at the embedded closure if there is one, by doing an unsafe cast:
+ * the result of __closure_type() is thrown away, it's used merely for type
+ * checking.
+ */
+#define __to_internal_closure(cl) \
+({ \
+ BUILD_BUG_ON(__closure_type(*cl) > MAX_CLOSURE_TYPE); \
+ (struct closure *) cl; \
+})
+
+#define closure_init_type(cl, parent, running) \
+do { \
+ struct closure *_cl = __to_internal_closure(cl); \
+ _cl->type = __closure_type(*(cl)); \
+ do_closure_init(_cl, parent, running); \
+} while (0)
+
+/**
+ * __closure_init() - Initialize a closure, skipping the memset()
+ *
+ * May be used instead of closure_init() when memory has already been zeroed.
+ */
+#define __closure_init(cl, parent) \
+ closure_init_type(cl, parent, true)
+
+/**
+ * closure_init() - Initialize a closure, setting the refcount to 1
+ * @cl: closure to initialize
+ * @parent: parent of the new closure. cl will take a refcount on it for its
+ * lifetime; may be NULL.
+ */
+#define closure_init(cl, parent) \
+do { \
+ memset((cl), 0, sizeof(*(cl))); \
+ __closure_init(cl, parent); \
+} while (0)
+
+static inline void closure_init_stack(struct closure *cl)
+{
+ memset(cl, 0, sizeof(struct closure));
+ atomic_set(&cl->remaining, CLOSURE_REMAINING_INITIALIZER|
+ CLOSURE_BLOCKING|CLOSURE_STACK);
+}
+
+/**
+ * closure_init_unlocked() - Initialize a closure but leave it unlocked.
+ * @cl: closure to initialize
+ *
+ * For when the closure will be used as a lock. The closure may not be used
+ * until after a closure_lock() or closure_trylock().
+ */
+#define closure_init_unlocked(cl) \
+do { \
+ memset((cl), 0, sizeof(*(cl))); \
+ closure_init_type(cl, NULL, false); \
+} while (0)
+
+/**
+ * closure_lock() - lock and initialize a closure.
+ * @cl: the closure to lock
+ * @parent: the new parent for this closure
+ *
+ * The closure must be of one of the types that has a waitlist (otherwise we
+ * wouldn't be able to sleep on contention).
+ *
+ * @parent has exactly the same meaning as in closure_init(); if non null, the
+ * closure will take a reference on @parent which will be released when it is
+ * unlocked.
+ */
+#define closure_lock(cl, parent) \
+ __closure_lock(__to_internal_closure(cl), parent, &(cl)->wait)
+
+/**
+ * closure_delay() - delay some number of jiffies
+ * @cl: the closure that will sleep
+ * @delay: the delay in jiffies
+ *
+ * Takes a refcount on @cl which will be released after @delay jiffies; this may
+ * be used to have a function run after a delay with continue_at(), or
+ * closure_sync() may be used for a convoluted version of msleep().
+ */
+#define closure_delay(cl, delay) \
+ __closure_delay(__to_internal_closure(cl), delay, &(cl)->timer)
+
+#define closure_flush(cl) \
+ __closure_flush(__to_internal_closure(cl), &(cl)->timer)
+
+#define closure_flush_sync(cl) \
+ __closure_flush_sync(__to_internal_closure(cl), &(cl)->timer)
+
+static inline void __closure_end_sleep(struct closure *cl)
+{
+ __set_current_state(TASK_RUNNING);
+
+ if (atomic_read(&cl->remaining) & CLOSURE_SLEEPING)
+ atomic_sub(CLOSURE_SLEEPING, &cl->remaining);
+}
+
+static inline void __closure_start_sleep(struct closure *cl)
+{
+ closure_set_ip(cl);
+ cl->task = current;
+ set_current_state(TASK_UNINTERRUPTIBLE);
+
+ if (!(atomic_read(&cl->remaining) & CLOSURE_SLEEPING))
+ atomic_add(CLOSURE_SLEEPING, &cl->remaining);
+}
+
+/**
+ * closure_blocking() - returns true if the closure is in blocking mode.
+ *
+ * If a closure is in blocking mode, closure_wait_event() will sleep until the
+ * condition is true instead of waiting asynchronously.
+ */
+static inline bool closure_blocking(struct closure *cl)
+{
+ return atomic_read(&cl->remaining) & CLOSURE_BLOCKING;
+}
+
+/**
+ * set_closure_blocking() - put a closure in blocking mode.
+ *
+ * If a closure is in blocking mode, closure_wait_event() will sleep until the
+ * condition is true instead of waiting asynchronously.
+ *
+ * Not thread safe - can only be called by the thread running the closure.
+ */
+static inline void set_closure_blocking(struct closure *cl)
+{
+ if (!closure_blocking(cl))
+ atomic_add(CLOSURE_BLOCKING, &cl->remaining);
+}
+
+/*
+ * Not thread safe - can only be called by the thread running the closure.
+ */
+static inline void clear_closure_blocking(struct closure *cl)
+{
+ if (closure_blocking(cl))
+ atomic_sub(CLOSURE_BLOCKING, &cl->remaining);
+}
+
+/**
+ * closure_wake_up() - wake up all closures on a wait list.
+ */
+static inline void closure_wake_up(struct closure_waitlist *list)
+{
+ smp_mb();
+ __closure_wake_up(list);
+}
+
+/*
+ * Wait on an event, synchronously or asynchronously - analogous to wait_event()
+ * but for closures.
+ *
+ * The loop is oddly structured so as to avoid a race; we must check the
+ * condition again after we've added ourself to the waitlist. We know if we were
+ * already on the waitlist because closure_wait() returns false; thus, we only
+ * schedule or break if closure_wait() returns false. If it returns true, we
+ * just loop again - rechecking the condition.
+ *
+ * The __closure_wake_up() is necessary because we may race with the event
+ * becoming true; i.e. we see event false -> wait -> recheck condition, but the
+ * thread that made the event true may have called closure_wake_up() before we
+ * added ourself to the wait list.
+ *
+ * We have to call closure_sync() at the end instead of just
+ * __closure_end_sleep() because a different thread might've called
+ * closure_wake_up() before us and gotten preempted before they dropped the
+ * refcount on our closure. If this was a stack allocated closure, that would be
+ * bad.
+ */
+#define __closure_wait_event(list, cl, condition, _block) \
+({ \
+ bool block = _block; \
+ typeof(condition) ret; \
+ \
+ while (1) { \
+ ret = (condition); \
+ if (ret) { \
+ __closure_wake_up(list); \
+ if (block) \
+ closure_sync(cl); \
+ \
+ break; \
+ } \
+ \
+ if (block) \
+ __closure_start_sleep(cl); \
+ \
+ if (!closure_wait(list, cl)) { \
+ if (!block) \
+ break; \
+ \
+ schedule(); \
+ } \
+ } \
+ \
+ ret; \
+})
+
+/**
+ * closure_wait_event() - wait on a condition, synchronously or asynchronously.
+ * @list: the wait list to wait on
+ * @cl: the closure that is doing the waiting
+ * @condition: a C expression for the event to wait for
+ *
+ * If the closure is in blocking mode, sleeps until the @condition evaluates to
+ * true - exactly like wait_event().
+ *
+ * If the closure is not in blocking mode, waits asynchronously; if the
+ * condition is currently false the @cl is put onto @list and returns. @list
+ * owns a refcount on @cl; closure_sync() or continue_at() may be used later to
+ * wait for another thread to wake up @list, which drops the refcount on @cl.
+ *
+ * Returns the value of @condition; @cl will be on @list iff @condition was
+ * false.
+ *
+ * closure_wake_up(@list) must be called after changing any variable that could
+ * cause @condition to become true.
+ */
+#define closure_wait_event(list, cl, condition) \
+ __closure_wait_event(list, cl, condition, closure_blocking(cl))
+
+#define closure_wait_event_async(list, cl, condition) \
+ __closure_wait_event(list, cl, condition, false)
+
+#define closure_wait_event_sync(list, cl, condition) \
+ __closure_wait_event(list, cl, condition, true)
+
+static inline void set_closure_fn(struct closure *cl, closure_fn *fn,
+ struct workqueue_struct *wq)
+{
+ BUG_ON(object_is_on_stack(cl));
+ closure_set_ip(cl);
+ cl->fn = fn;
+ cl->wq = wq;
+ /* between atomic_dec() in closure_put() */
+ smp_mb__before_atomic_dec();
+}
+
+#define continue_at(_cl, _fn, _wq) \
+do { \
+ set_closure_fn(_cl, _fn, _wq); \
+ closure_sub(_cl, CLOSURE_RUNNING + 1); \
+ return; \
+} while (0)
+
+#define closure_return(_cl) continue_at((_cl), NULL, NULL)
+
+#define continue_at_nobarrier(_cl, _fn, _wq) \
+do { \
+ set_closure_fn(_cl, _fn, _wq); \
+ closure_queue(cl); \
+ return; \
+} while (0)
+
+#define closure_return_with_destructor(_cl, _destructor) \
+do { \
+ set_closure_fn(_cl, _destructor, NULL); \
+ closure_sub(_cl, CLOSURE_RUNNING - CLOSURE_DESTRUCTOR + 1); \
+ return; \
+} while (0)
+
+static inline void closure_call(struct closure *cl, closure_fn fn,
+ struct workqueue_struct *wq,
+ struct closure *parent)
+{
+ closure_init(cl, parent);
+ continue_at_nobarrier(cl, fn, wq);
+}
+
+static inline void closure_trylock_call(struct closure *cl, closure_fn fn,
+ struct workqueue_struct *wq,
+ struct closure *parent)
+{
+ if (closure_trylock(cl, parent))
+ continue_at_nobarrier(cl, fn, wq);
+}
+
+#endif /* _LINUX_CLOSURE_H */
--- /dev/null
+/*
+ * Assorted bcache debug code
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+#include <linux/console.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/seq_file.h>
+
+static struct dentry *debug;
+
+const char *bch_ptr_status(struct cache_set *c, const struct bkey *k)
+{
+ unsigned i;
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ if (ptr_available(c, k, i)) {
+ struct cache *ca = PTR_CACHE(c, k, i);
+ size_t bucket = PTR_BUCKET_NR(c, k, i);
+ size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
+
+ if (KEY_SIZE(k) + r > c->sb.bucket_size)
+ return "bad, length too big";
+ if (bucket < ca->sb.first_bucket)
+ return "bad, short offset";
+ if (bucket >= ca->sb.nbuckets)
+ return "bad, offset past end of device";
+ if (ptr_stale(c, k, i))
+ return "stale";
+ }
+
+ if (!bkey_cmp(k, &ZERO_KEY))
+ return "bad, null key";
+ if (!KEY_PTRS(k))
+ return "bad, no pointers";
+ if (!KEY_SIZE(k))
+ return "zeroed key";
+ return "";
+}
+
+struct keyprint_hack bch_pkey(const struct bkey *k)
+{
+ unsigned i = 0;
+ struct keyprint_hack r;
+ char *out = r.s, *end = r.s + KEYHACK_SIZE;
+
+#define p(...) (out += scnprintf(out, end - out, __VA_ARGS__))
+
+ p("%llu:%llu len %llu -> [", KEY_INODE(k), KEY_OFFSET(k), KEY_SIZE(k));
+
+ if (KEY_PTRS(k))
+ while (1) {
+ p("%llu:%llu gen %llu",
+ PTR_DEV(k, i), PTR_OFFSET(k, i), PTR_GEN(k, i));
+
+ if (++i == KEY_PTRS(k))
+ break;
+
+ p(", ");
+ }
+
+ p("]");
+
+ if (KEY_DIRTY(k))
+ p(" dirty");
+ if (KEY_CSUM(k))
+ p(" cs%llu %llx", KEY_CSUM(k), k->ptr[1]);
+#undef p
+ return r;
+}
+
+struct keyprint_hack bch_pbtree(const struct btree *b)
+{
+ struct keyprint_hack r;
+
+ snprintf(r.s, 40, "%li level %i/%i", PTR_BUCKET_NR(b->c, &b->key, 0),
+ b->level, b->c->root ? b->c->root->level : -1);
+ return r;
+}
+
+#if defined(CONFIG_BCACHE_DEBUG) || defined(CONFIG_BCACHE_EDEBUG)
+
+static bool skipped_backwards(struct btree *b, struct bkey *k)
+{
+ return bkey_cmp(k, (!b->level)
+ ? &START_KEY(bkey_next(k))
+ : bkey_next(k)) > 0;
+}
+
+static void dump_bset(struct btree *b, struct bset *i)
+{
+ struct bkey *k;
+ unsigned j;
+
+ for (k = i->start; k < end(i); k = bkey_next(k)) {
+ printk(KERN_ERR "block %zu key %zi/%u: %s", index(i, b),
+ (uint64_t *) k - i->d, i->keys, pkey(k));
+
+ for (j = 0; j < KEY_PTRS(k); j++) {
+ size_t n = PTR_BUCKET_NR(b->c, k, j);
+ printk(" bucket %zu", n);
+
+ if (n >= b->c->sb.first_bucket && n < b->c->sb.nbuckets)
+ printk(" prio %i",
+ PTR_BUCKET(b->c, k, j)->prio);
+ }
+
+ printk(" %s\n", bch_ptr_status(b->c, k));
+
+ if (bkey_next(k) < end(i) &&
+ skipped_backwards(b, k))
+ printk(KERN_ERR "Key skipped backwards\n");
+ }
+}
+
+#endif
+
+#ifdef CONFIG_BCACHE_DEBUG
+
+void bch_btree_verify(struct btree *b, struct bset *new)
+{
+ struct btree *v = b->c->verify_data;
+ struct closure cl;
+ closure_init_stack(&cl);
+
+ if (!b->c->verify)
+ return;
+
+ closure_wait_event(&b->io.wait, &cl,
+ atomic_read(&b->io.cl.remaining) == -1);
+
+ mutex_lock(&b->c->verify_lock);
+
+ bkey_copy(&v->key, &b->key);
+ v->written = 0;
+ v->level = b->level;
+
+ bch_btree_read(v);
+ closure_wait_event(&v->io.wait, &cl,
+ atomic_read(&b->io.cl.remaining) == -1);
+
+ if (new->keys != v->sets[0].data->keys ||
+ memcmp(new->start,
+ v->sets[0].data->start,
+ (void *) end(new) - (void *) new->start)) {
+ unsigned i, j;
+
+ console_lock();
+
+ printk(KERN_ERR "*** original memory node:\n");
+ for (i = 0; i <= b->nsets; i++)
+ dump_bset(b, b->sets[i].data);
+
+ printk(KERN_ERR "*** sorted memory node:\n");
+ dump_bset(b, new);
+
+ printk(KERN_ERR "*** on disk node:\n");
+ dump_bset(v, v->sets[0].data);
+
+ for (j = 0; j < new->keys; j++)
+ if (new->d[j] != v->sets[0].data->d[j])
+ break;
+
+ console_unlock();
+ panic("verify failed at %u\n", j);
+ }
+
+ mutex_unlock(&b->c->verify_lock);
+}
+
+static void data_verify_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+ closure_put(cl);
+}
+
+void bch_data_verify(struct search *s)
+{
+ char name[BDEVNAME_SIZE];
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+ struct closure *cl = &s->cl;
+ struct bio *check;
+ struct bio_vec *bv;
+ int i;
+
+ if (!s->unaligned_bvec)
+ bio_for_each_segment(bv, s->orig_bio, i)
+ bv->bv_offset = 0, bv->bv_len = PAGE_SIZE;
+
+ check = bio_clone(s->orig_bio, GFP_NOIO);
+ if (!check)
+ return;
+
+ if (bio_alloc_pages(check, GFP_NOIO))
+ goto out_put;
+
+ check->bi_rw = READ_SYNC;
+ check->bi_private = cl;
+ check->bi_end_io = data_verify_endio;
+
+ closure_bio_submit(check, cl, &dc->disk);
+ closure_sync(cl);
+
+ bio_for_each_segment(bv, s->orig_bio, i) {
+ void *p1 = kmap(bv->bv_page);
+ void *p2 = kmap(check->bi_io_vec[i].bv_page);
+
+ if (memcmp(p1 + bv->bv_offset,
+ p2 + bv->bv_offset,
+ bv->bv_len))
+ printk(KERN_ERR "bcache (%s): verify failed"
+ " at sector %llu\n",
+ bdevname(dc->bdev, name),
+ (uint64_t) s->orig_bio->bi_sector);
+
+ kunmap(bv->bv_page);
+ kunmap(check->bi_io_vec[i].bv_page);
+ }
+
+ __bio_for_each_segment(bv, check, i, 0)
+ __free_page(bv->bv_page);
+out_put:
+ bio_put(check);
+}
+
+#endif
+
+#ifdef CONFIG_BCACHE_EDEBUG
+
+unsigned bch_count_data(struct btree *b)
+{
+ unsigned ret = 0;
+ struct btree_iter iter;
+ struct bkey *k;
+
+ if (!b->level)
+ for_each_key(b, k, &iter)
+ ret += KEY_SIZE(k);
+ return ret;
+}
+
+static void vdump_bucket_and_panic(struct btree *b, const char *fmt,
+ va_list args)
+{
+ unsigned i;
+
+ console_lock();
+
+ for (i = 0; i <= b->nsets; i++)
+ dump_bset(b, b->sets[i].data);
+
+ vprintk(fmt, args);
+
+ console_unlock();
+
+ panic("at %s\n", pbtree(b));
+}
+
+void bch_check_key_order_msg(struct btree *b, struct bset *i,
+ const char *fmt, ...)
+{
+ struct bkey *k;
+
+ if (!i->keys)
+ return;
+
+ for (k = i->start; bkey_next(k) < end(i); k = bkey_next(k))
+ if (skipped_backwards(b, k)) {
+ va_list args;
+ va_start(args, fmt);
+
+ vdump_bucket_and_panic(b, fmt, args);
+ va_end(args);
+ }
+}
+
+void bch_check_keys(struct btree *b, const char *fmt, ...)
+{
+ va_list args;
+ struct bkey *k, *p = NULL;
+ struct btree_iter iter;
+
+ if (b->level)
+ return;
+
+ for_each_key(b, k, &iter) {
+ if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0) {
+ printk(KERN_ERR "Keys out of order:\n");
+ goto bug;
+ }
+
+ if (bch_ptr_invalid(b, k))
+ continue;
+
+ if (p && bkey_cmp(p, &START_KEY(k)) > 0) {
+ printk(KERN_ERR "Overlapping keys:\n");
+ goto bug;
+ }
+ p = k;
+ }
+ return;
+bug:
+ va_start(args, fmt);
+ vdump_bucket_and_panic(b, fmt, args);
+ va_end(args);
+}
+
+#endif
+
+#ifdef CONFIG_DEBUG_FS
+
+/* XXX: cache set refcounting */
+
+struct dump_iterator {
+ char buf[PAGE_SIZE];
+ size_t bytes;
+ struct cache_set *c;
+ struct keybuf keys;
+};
+
+static bool dump_pred(struct keybuf *buf, struct bkey *k)
+{
+ return true;
+}
+
+static ssize_t bch_dump_read(struct file *file, char __user *buf,
+ size_t size, loff_t *ppos)
+{
+ struct dump_iterator *i = file->private_data;
+ ssize_t ret = 0;
+
+ while (size) {
+ struct keybuf_key *w;
+ unsigned bytes = min(i->bytes, size);
+
+ int err = copy_to_user(buf, i->buf, bytes);
+ if (err)
+ return err;
+
+ ret += bytes;
+ buf += bytes;
+ size -= bytes;
+ i->bytes -= bytes;
+ memmove(i->buf, i->buf + bytes, i->bytes);
+
+ if (i->bytes)
+ break;
+
+ w = bch_keybuf_next_rescan(i->c, &i->keys, &MAX_KEY);
+ if (!w)
+ break;
+
+ i->bytes = snprintf(i->buf, PAGE_SIZE, "%s\n", pkey(&w->key));
+ bch_keybuf_del(&i->keys, w);
+ }
+
+ return ret;
+}
+
+static int bch_dump_open(struct inode *inode, struct file *file)
+{
+ struct cache_set *c = inode->i_private;
+ struct dump_iterator *i;
+
+ i = kzalloc(sizeof(struct dump_iterator), GFP_KERNEL);
+ if (!i)
+ return -ENOMEM;
+
+ file->private_data = i;
+ i->c = c;
+ bch_keybuf_init(&i->keys, dump_pred);
+ i->keys.last_scanned = KEY(0, 0, 0);
+
+ return 0;
+}
+
+static int bch_dump_release(struct inode *inode, struct file *file)
+{
+ kfree(file->private_data);
+ return 0;
+}
+
+static const struct file_operations cache_set_debug_ops = {
+ .owner = THIS_MODULE,
+ .open = bch_dump_open,
+ .read = bch_dump_read,
+ .release = bch_dump_release
+};
+
+void bch_debug_init_cache_set(struct cache_set *c)
+{
+ if (!IS_ERR_OR_NULL(debug)) {
+ char name[50];
+ snprintf(name, 50, "bcache-%pU", c->sb.set_uuid);
+
+ c->debug = debugfs_create_file(name, 0400, debug, c,
+ &cache_set_debug_ops);
+ }
+}
+
+#endif
+
+#ifdef CONFIG_BCACHE_DEBUG
+static ssize_t btree_fuzz(struct kobject *k, struct kobj_attribute *a,
+ const char *buffer, size_t size)
+{
+ void dump(struct btree *b)
+ {
+ struct bset *i;
+
+ for (i = b->sets[0].data;
+ index(i, b) < btree_blocks(b) &&
+ i->seq == b->sets[0].data->seq;
+ i = ((void *) i) + set_blocks(i, b->c) * block_bytes(b->c))
+ dump_bset(b, i);
+ }
+
+ struct cache_sb *sb;
+ struct cache_set *c;
+ struct btree *all[3], *b, *fill, *orig;
+ int j;
+
+ struct btree_op op;
+ bch_btree_op_init_stack(&op);
+
+ sb = kzalloc(sizeof(struct cache_sb), GFP_KERNEL);
+ if (!sb)
+ return -ENOMEM;
+
+ sb->bucket_size = 128;
+ sb->block_size = 4;
+
+ c = bch_cache_set_alloc(sb);
+ if (!c)
+ return -ENOMEM;
+
+ for (j = 0; j < 3; j++) {
+ BUG_ON(list_empty(&c->btree_cache));
+ all[j] = list_first_entry(&c->btree_cache, struct btree, list);
+ list_del_init(&all[j]->list);
+
+ all[j]->key = KEY(0, 0, c->sb.bucket_size);
+ bkey_copy_key(&all[j]->key, &MAX_KEY);
+ }
+
+ b = all[0];
+ fill = all[1];
+ orig = all[2];
+
+ while (1) {
+ for (j = 0; j < 3; j++)
+ all[j]->written = all[j]->nsets = 0;
+
+ bch_bset_init_next(b);
+
+ while (1) {
+ struct bset *i = write_block(b);
+ struct bkey *k = op.keys.top;
+ unsigned rand;
+
+ bkey_init(k);
+ rand = get_random_int();
+
+ op.type = rand & 1
+ ? BTREE_INSERT
+ : BTREE_REPLACE;
+ rand >>= 1;
+
+ SET_KEY_SIZE(k, bucket_remainder(c, rand));
+ rand >>= c->bucket_bits;
+ rand &= 1024 * 512 - 1;
+ rand += c->sb.bucket_size;
+ SET_KEY_OFFSET(k, rand);
+#if 0
+ SET_KEY_PTRS(k, 1);
+#endif
+ bch_keylist_push(&op.keys);
+ bch_btree_insert_keys(b, &op);
+
+ if (should_split(b) ||
+ set_blocks(i, b->c) !=
+ __set_blocks(i, i->keys + 15, b->c)) {
+ i->csum = csum_set(i);
+
+ memcpy(write_block(fill),
+ i, set_bytes(i));
+
+ b->written += set_blocks(i, b->c);
+ fill->written = b->written;
+ if (b->written == btree_blocks(b))
+ break;
+
+ bch_btree_sort_lazy(b);
+ bch_bset_init_next(b);
+ }
+ }
+
+ memcpy(orig->sets[0].data,
+ fill->sets[0].data,
+ btree_bytes(c));
+
+ bch_btree_sort(b);
+ fill->written = 0;
+ bch_btree_read_done(&fill->io.cl);
+
+ if (b->sets[0].data->keys != fill->sets[0].data->keys ||
+ memcmp(b->sets[0].data->start,
+ fill->sets[0].data->start,
+ b->sets[0].data->keys * sizeof(uint64_t))) {
+ struct bset *i = b->sets[0].data;
+ struct bkey *k, *l;
+
+ for (k = i->start,
+ l = fill->sets[0].data->start;
+ k < end(i);
+ k = bkey_next(k), l = bkey_next(l))
+ if (bkey_cmp(k, l) ||
+ KEY_SIZE(k) != KEY_SIZE(l))
+ pr_err("key %zi differs: %s "
+ "!= %s", (uint64_t *) k - i->d,
+ pkey(k), pkey(l));
+
+ for (j = 0; j < 3; j++) {
+ pr_err("**** Set %i ****", j);
+ dump(all[j]);
+ }
+ panic("\n");
+ }
+
+ pr_info("fuzz complete: %i keys", b->sets[0].data->keys);
+ }
+}
+
+kobj_attribute_write(fuzz, btree_fuzz);
+#endif
+
+void bch_debug_exit(void)
+{
+ if (!IS_ERR_OR_NULL(debug))
+ debugfs_remove_recursive(debug);
+}
+
+int __init bch_debug_init(struct kobject *kobj)
+{
+ int ret = 0;
+#ifdef CONFIG_BCACHE_DEBUG
+ ret = sysfs_create_file(kobj, &ksysfs_fuzz.attr);
+ if (ret)
+ return ret;
+#endif
+
+ debug = debugfs_create_dir("bcache", NULL);
+ return ret;
+}
--- /dev/null
+#ifndef _BCACHE_DEBUG_H
+#define _BCACHE_DEBUG_H
+
+/* Btree/bkey debug printing */
+
+#define KEYHACK_SIZE 80
+struct keyprint_hack {
+ char s[KEYHACK_SIZE];
+};
+
+struct keyprint_hack bch_pkey(const struct bkey *k);
+struct keyprint_hack bch_pbtree(const struct btree *b);
+#define pkey(k) (&bch_pkey(k).s[0])
+#define pbtree(b) (&bch_pbtree(b).s[0])
+
+#ifdef CONFIG_BCACHE_EDEBUG
+
+unsigned bch_count_data(struct btree *);
+void bch_check_key_order_msg(struct btree *, struct bset *, const char *, ...);
+void bch_check_keys(struct btree *, const char *, ...);
+
+#define bch_check_key_order(b, i) \
+ bch_check_key_order_msg(b, i, "keys out of order")
+#define EBUG_ON(cond) BUG_ON(cond)
+
+#else /* EDEBUG */
+
+#define bch_count_data(b) 0
+#define bch_check_key_order(b, i) do {} while (0)
+#define bch_check_key_order_msg(b, i, ...) do {} while (0)
+#define bch_check_keys(b, ...) do {} while (0)
+#define EBUG_ON(cond) do {} while (0)
+
+#endif
+
+#ifdef CONFIG_BCACHE_DEBUG
+
+void bch_btree_verify(struct btree *, struct bset *);
+void bch_data_verify(struct search *);
+
+#else /* DEBUG */
+
+static inline void bch_btree_verify(struct btree *b, struct bset *i) {}
+static inline void bch_data_verify(struct search *s) {};
+
+#endif
+
+#ifdef CONFIG_DEBUG_FS
+void bch_debug_init_cache_set(struct cache_set *);
+#else
+static inline void bch_debug_init_cache_set(struct cache_set *c) {}
+#endif
+
+#endif
--- /dev/null
+/*
+ * Some low level IO code, and hacks for various block layer limitations
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "bset.h"
+#include "debug.h"
+
+static void bch_bi_idx_hack_endio(struct bio *bio, int error)
+{
+ struct bio *p = bio->bi_private;
+
+ bio_endio(p, error);
+ bio_put(bio);
+}
+
+static void bch_generic_make_request_hack(struct bio *bio)
+{
+ if (bio->bi_idx) {
+ struct bio *clone = bio_alloc(GFP_NOIO, bio_segments(bio));
+
+ memcpy(clone->bi_io_vec,
+ bio_iovec(bio),
+ bio_segments(bio) * sizeof(struct bio_vec));
+
+ clone->bi_sector = bio->bi_sector;
+ clone->bi_bdev = bio->bi_bdev;
+ clone->bi_rw = bio->bi_rw;
+ clone->bi_vcnt = bio_segments(bio);
+ clone->bi_size = bio->bi_size;
+
+ clone->bi_private = bio;
+ clone->bi_end_io = bch_bi_idx_hack_endio;
+
+ bio = clone;
+ }
+
+ generic_make_request(bio);
+}
+
+/**
+ * bch_bio_split - split a bio
+ * @bio: bio to split
+ * @sectors: number of sectors to split from the front of @bio
+ * @gfp: gfp mask
+ * @bs: bio set to allocate from
+ *
+ * Allocates and returns a new bio which represents @sectors from the start of
+ * @bio, and updates @bio to represent the remaining sectors.
+ *
+ * If bio_sectors(@bio) was less than or equal to @sectors, returns @bio
+ * unchanged.
+ *
+ * The newly allocated bio will point to @bio's bi_io_vec, if the split was on a
+ * bvec boundry; it is the caller's responsibility to ensure that @bio is not
+ * freed before the split.
+ *
+ * If bch_bio_split() is running under generic_make_request(), it's not safe to
+ * allocate more than one bio from the same bio set. Therefore, if it is running
+ * under generic_make_request() it masks out __GFP_WAIT when doing the
+ * allocation. The caller must check for failure if there's any possibility of
+ * it being called from under generic_make_request(); it is then the caller's
+ * responsibility to retry from a safe context (by e.g. punting to workqueue).
+ */
+struct bio *bch_bio_split(struct bio *bio, int sectors,
+ gfp_t gfp, struct bio_set *bs)
+{
+ unsigned idx = bio->bi_idx, vcnt = 0, nbytes = sectors << 9;
+ struct bio_vec *bv;
+ struct bio *ret = NULL;
+
+ BUG_ON(sectors <= 0);
+
+ /*
+ * If we're being called from underneath generic_make_request() and we
+ * already allocated any bios from this bio set, we risk deadlock if we
+ * use the mempool. So instead, we possibly fail and let the caller punt
+ * to workqueue or somesuch and retry in a safe context.
+ */
+ if (current->bio_list)
+ gfp &= ~__GFP_WAIT;
+
+ if (sectors >= bio_sectors(bio))
+ return bio;
+
+ if (bio->bi_rw & REQ_DISCARD) {
+ ret = bio_alloc_bioset(gfp, 1, bs);
+ idx = 0;
+ goto out;
+ }
+
+ bio_for_each_segment(bv, bio, idx) {
+ vcnt = idx - bio->bi_idx;
+
+ if (!nbytes) {
+ ret = bio_alloc_bioset(gfp, vcnt, bs);
+ if (!ret)
+ return NULL;
+
+ memcpy(ret->bi_io_vec, bio_iovec(bio),
+ sizeof(struct bio_vec) * vcnt);
+
+ break;
+ } else if (nbytes < bv->bv_len) {
+ ret = bio_alloc_bioset(gfp, ++vcnt, bs);
+ if (!ret)
+ return NULL;
+
+ memcpy(ret->bi_io_vec, bio_iovec(bio),
+ sizeof(struct bio_vec) * vcnt);
+
+ ret->bi_io_vec[vcnt - 1].bv_len = nbytes;
+ bv->bv_offset += nbytes;
+ bv->bv_len -= nbytes;
+ break;
+ }
+
+ nbytes -= bv->bv_len;
+ }
+out:
+ ret->bi_bdev = bio->bi_bdev;
+ ret->bi_sector = bio->bi_sector;
+ ret->bi_size = sectors << 9;
+ ret->bi_rw = bio->bi_rw;
+ ret->bi_vcnt = vcnt;
+ ret->bi_max_vecs = vcnt;
+
+ bio->bi_sector += sectors;
+ bio->bi_size -= sectors << 9;
+ bio->bi_idx = idx;
+
+ if (bio_integrity(bio)) {
+ if (bio_integrity_clone(ret, bio, gfp)) {
+ bio_put(ret);
+ return NULL;
+ }
+
+ bio_integrity_trim(ret, 0, bio_sectors(ret));
+ bio_integrity_trim(bio, bio_sectors(ret), bio_sectors(bio));
+ }
+
+ return ret;
+}
+
+static unsigned bch_bio_max_sectors(struct bio *bio)
+{
+ unsigned ret = bio_sectors(bio);
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+ struct bio_vec *bv, *end = bio_iovec(bio) +
+ min_t(int, bio_segments(bio), queue_max_segments(q));
+
+ struct bvec_merge_data bvm = {
+ .bi_bdev = bio->bi_bdev,
+ .bi_sector = bio->bi_sector,
+ .bi_size = 0,
+ .bi_rw = bio->bi_rw,
+ };
+
+ if (bio->bi_rw & REQ_DISCARD)
+ return min(ret, q->limits.max_discard_sectors);
+
+ if (bio_segments(bio) > queue_max_segments(q) ||
+ q->merge_bvec_fn) {
+ ret = 0;
+
+ for (bv = bio_iovec(bio); bv < end; bv++) {
+ if (q->merge_bvec_fn &&
+ q->merge_bvec_fn(q, &bvm, bv) < (int) bv->bv_len)
+ break;
+
+ ret += bv->bv_len >> 9;
+ bvm.bi_size += bv->bv_len;
+ }
+
+ if (ret >= (BIO_MAX_PAGES * PAGE_SIZE) >> 9)
+ return (BIO_MAX_PAGES * PAGE_SIZE) >> 9;
+ }
+
+ ret = min(ret, queue_max_sectors(q));
+
+ WARN_ON(!ret);
+ ret = max_t(int, ret, bio_iovec(bio)->bv_len >> 9);
+
+ return ret;
+}
+
+static void bch_bio_submit_split_done(struct closure *cl)
+{
+ struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
+
+ s->bio->bi_end_io = s->bi_end_io;
+ s->bio->bi_private = s->bi_private;
+ bio_endio(s->bio, 0);
+
+ closure_debug_destroy(&s->cl);
+ mempool_free(s, s->p->bio_split_hook);
+}
+
+static void bch_bio_submit_split_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+ struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
+
+ if (error)
+ clear_bit(BIO_UPTODATE, &s->bio->bi_flags);
+
+ bio_put(bio);
+ closure_put(cl);
+}
+
+static void __bch_bio_submit_split(struct closure *cl)
+{
+ struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
+ struct bio *bio = s->bio, *n;
+
+ do {
+ n = bch_bio_split(bio, bch_bio_max_sectors(bio),
+ GFP_NOIO, s->p->bio_split);
+ if (!n)
+ continue_at(cl, __bch_bio_submit_split, system_wq);
+
+ n->bi_end_io = bch_bio_submit_split_endio;
+ n->bi_private = cl;
+
+ closure_get(cl);
+ bch_generic_make_request_hack(n);
+ } while (n != bio);
+
+ continue_at(cl, bch_bio_submit_split_done, NULL);
+}
+
+void bch_generic_make_request(struct bio *bio, struct bio_split_pool *p)
+{
+ struct bio_split_hook *s;
+
+ if (!bio_has_data(bio) && !(bio->bi_rw & REQ_DISCARD))
+ goto submit;
+
+ if (bio_sectors(bio) <= bch_bio_max_sectors(bio))
+ goto submit;
+
+ s = mempool_alloc(p->bio_split_hook, GFP_NOIO);
+
+ s->bio = bio;
+ s->p = p;
+ s->bi_end_io = bio->bi_end_io;
+ s->bi_private = bio->bi_private;
+ bio_get(bio);
+
+ closure_call(&s->cl, __bch_bio_submit_split, NULL, NULL);
+ return;
+submit:
+ bch_generic_make_request_hack(bio);
+}
+
+/* Bios with headers */
+
+void bch_bbio_free(struct bio *bio, struct cache_set *c)
+{
+ struct bbio *b = container_of(bio, struct bbio, bio);
+ mempool_free(b, c->bio_meta);
+}
+
+struct bio *bch_bbio_alloc(struct cache_set *c)
+{
+ struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO);
+ struct bio *bio = &b->bio;
+
+ bio_init(bio);
+ bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
+ bio->bi_max_vecs = bucket_pages(c);
+ bio->bi_io_vec = bio->bi_inline_vecs;
+
+ return bio;
+}
+
+void __bch_submit_bbio(struct bio *bio, struct cache_set *c)
+{
+ struct bbio *b = container_of(bio, struct bbio, bio);
+
+ bio->bi_sector = PTR_OFFSET(&b->key, 0);
+ bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev;
+
+ b->submit_time_us = local_clock_us();
+ closure_bio_submit(bio, bio->bi_private, PTR_CACHE(c, &b->key, 0));
+}
+
+void bch_submit_bbio(struct bio *bio, struct cache_set *c,
+ struct bkey *k, unsigned ptr)
+{
+ struct bbio *b = container_of(bio, struct bbio, bio);
+ bch_bkey_copy_single_ptr(&b->key, k, ptr);
+ __bch_submit_bbio(bio, c);
+}
+
+/* IO errors */
+
+void bch_count_io_errors(struct cache *ca, int error, const char *m)
+{
+ /*
+ * The halflife of an error is:
+ * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
+ */
+
+ if (ca->set->error_decay) {
+ unsigned count = atomic_inc_return(&ca->io_count);
+
+ while (count > ca->set->error_decay) {
+ unsigned errors;
+ unsigned old = count;
+ unsigned new = count - ca->set->error_decay;
+
+ /*
+ * First we subtract refresh from count; each time we
+ * succesfully do so, we rescale the errors once:
+ */
+
+ count = atomic_cmpxchg(&ca->io_count, old, new);
+
+ if (count == old) {
+ count = new;
+
+ errors = atomic_read(&ca->io_errors);
+ do {
+ old = errors;
+ new = ((uint64_t) errors * 127) / 128;
+ errors = atomic_cmpxchg(&ca->io_errors,
+ old, new);
+ } while (old != errors);
+ }
+ }
+ }
+
+ if (error) {
+ char buf[BDEVNAME_SIZE];
+ unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT,
+ &ca->io_errors);
+ errors >>= IO_ERROR_SHIFT;
+
+ if (errors < ca->set->error_limit)
+ pr_err("%s: IO error on %s, recovering",
+ bdevname(ca->bdev, buf), m);
+ else
+ bch_cache_set_error(ca->set,
+ "%s: too many IO errors %s",
+ bdevname(ca->bdev, buf), m);
+ }
+}
+
+void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio,
+ int error, const char *m)
+{
+ struct bbio *b = container_of(bio, struct bbio, bio);
+ struct cache *ca = PTR_CACHE(c, &b->key, 0);
+
+ unsigned threshold = bio->bi_rw & REQ_WRITE
+ ? c->congested_write_threshold_us
+ : c->congested_read_threshold_us;
+
+ if (threshold) {
+ unsigned t = local_clock_us();
+
+ int us = t - b->submit_time_us;
+ int congested = atomic_read(&c->congested);
+
+ if (us > (int) threshold) {
+ int ms = us / 1024;
+ c->congested_last_us = t;
+
+ ms = min(ms, CONGESTED_MAX + congested);
+ atomic_sub(ms, &c->congested);
+ } else if (congested < 0)
+ atomic_inc(&c->congested);
+ }
+
+ bch_count_io_errors(ca, error, m);
+}
+
+void bch_bbio_endio(struct cache_set *c, struct bio *bio,
+ int error, const char *m)
+{
+ struct closure *cl = bio->bi_private;
+
+ bch_bbio_count_io_errors(c, bio, error, m);
+ bio_put(bio);
+ closure_put(cl);
+}
--- /dev/null
+/*
+ * bcache journalling code, for btree insertions
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+/*
+ * Journal replay/recovery:
+ *
+ * This code is all driven from run_cache_set(); we first read the journal
+ * entries, do some other stuff, then we mark all the keys in the journal
+ * entries (same as garbage collection would), then we replay them - reinserting
+ * them into the cache in precisely the same order as they appear in the
+ * journal.
+ *
+ * We only journal keys that go in leaf nodes, which simplifies things quite a
+ * bit.
+ */
+
+static void journal_read_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+ closure_put(cl);
+}
+
+static int journal_read_bucket(struct cache *ca, struct list_head *list,
+ struct btree_op *op, unsigned bucket_index)
+{
+ struct journal_device *ja = &ca->journal;
+ struct bio *bio = &ja->bio;
+
+ struct journal_replay *i;
+ struct jset *j, *data = ca->set->journal.w[0].data;
+ unsigned len, left, offset = 0;
+ int ret = 0;
+ sector_t bucket = bucket_to_sector(ca->set, ca->sb.d[bucket_index]);
+
+ pr_debug("reading %llu", (uint64_t) bucket);
+
+ while (offset < ca->sb.bucket_size) {
+reread: left = ca->sb.bucket_size - offset;
+ len = min_t(unsigned, left, PAGE_SECTORS * 8);
+
+ bio_reset(bio);
+ bio->bi_sector = bucket + offset;
+ bio->bi_bdev = ca->bdev;
+ bio->bi_rw = READ;
+ bio->bi_size = len << 9;
+
+ bio->bi_end_io = journal_read_endio;
+ bio->bi_private = &op->cl;
+ bio_map(bio, data);
+
+ closure_bio_submit(bio, &op->cl, ca);
+ closure_sync(&op->cl);
+
+ /* This function could be simpler now since we no longer write
+ * journal entries that overlap bucket boundaries; this means
+ * the start of a bucket will always have a valid journal entry
+ * if it has any journal entries at all.
+ */
+
+ j = data;
+ while (len) {
+ struct list_head *where;
+ size_t blocks, bytes = set_bytes(j);
+
+ if (j->magic != jset_magic(ca->set))
+ return ret;
+
+ if (bytes > left << 9)
+ return ret;
+
+ if (bytes > len << 9)
+ goto reread;
+
+ if (j->csum != csum_set(j))
+ return ret;
+
+ blocks = set_blocks(j, ca->set);
+
+ while (!list_empty(list)) {
+ i = list_first_entry(list,
+ struct journal_replay, list);
+ if (i->j.seq >= j->last_seq)
+ break;
+ list_del(&i->list);
+ kfree(i);
+ }
+
+ list_for_each_entry_reverse(i, list, list) {
+ if (j->seq == i->j.seq)
+ goto next_set;
+
+ if (j->seq < i->j.last_seq)
+ goto next_set;
+
+ if (j->seq > i->j.seq) {
+ where = &i->list;
+ goto add;
+ }
+ }
+
+ where = list;
+add:
+ i = kmalloc(offsetof(struct journal_replay, j) +
+ bytes, GFP_KERNEL);
+ if (!i)
+ return -ENOMEM;
+ memcpy(&i->j, j, bytes);
+ list_add(&i->list, where);
+ ret = 1;
+
+ ja->seq[bucket_index] = j->seq;
+next_set:
+ offset += blocks * ca->sb.block_size;
+ len -= blocks * ca->sb.block_size;
+ j = ((void *) j) + blocks * block_bytes(ca);
+ }
+ }
+
+ return ret;
+}
+
+int bch_journal_read(struct cache_set *c, struct list_head *list,
+ struct btree_op *op)
+{
+#define read_bucket(b) \
+ ({ \
+ int ret = journal_read_bucket(ca, list, op, b); \
+ __set_bit(b, bitmap); \
+ if (ret < 0) \
+ return ret; \
+ ret; \
+ })
+
+ struct cache *ca;
+ unsigned iter;
+
+ for_each_cache(ca, c, iter) {
+ struct journal_device *ja = &ca->journal;
+ unsigned long bitmap[SB_JOURNAL_BUCKETS / BITS_PER_LONG];
+ unsigned i, l, r, m;
+ uint64_t seq;
+
+ bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);
+ pr_debug("%u journal buckets", ca->sb.njournal_buckets);
+
+ /* Read journal buckets ordered by golden ratio hash to quickly
+ * find a sequence of buckets with valid journal entries
+ */
+ for (i = 0; i < ca->sb.njournal_buckets; i++) {
+ l = (i * 2654435769U) % ca->sb.njournal_buckets;
+
+ if (test_bit(l, bitmap))
+ break;
+
+ if (read_bucket(l))
+ goto bsearch;
+ }
+
+ /* If that fails, check all the buckets we haven't checked
+ * already
+ */
+ pr_debug("falling back to linear search");
+
+ for (l = 0; l < ca->sb.njournal_buckets; l++) {
+ if (test_bit(l, bitmap))
+ continue;
+
+ if (read_bucket(l))
+ goto bsearch;
+ }
+bsearch:
+ /* Binary search */
+ m = r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
+ pr_debug("starting binary search, l %u r %u", l, r);
+
+ while (l + 1 < r) {
+ m = (l + r) >> 1;
+
+ if (read_bucket(m))
+ l = m;
+ else
+ r = m;
+ }
+
+ /* Read buckets in reverse order until we stop finding more
+ * journal entries
+ */
+ pr_debug("finishing up");
+ l = m;
+
+ while (1) {
+ if (!l--)
+ l = ca->sb.njournal_buckets - 1;
+
+ if (l == m)
+ break;
+
+ if (test_bit(l, bitmap))
+ continue;
+
+ if (!read_bucket(l))
+ break;
+ }
+
+ seq = 0;
+
+ for (i = 0; i < ca->sb.njournal_buckets; i++)
+ if (ja->seq[i] > seq) {
+ seq = ja->seq[i];
+ ja->cur_idx = ja->discard_idx =
+ ja->last_idx = i;
+
+ }
+ }
+
+ c->journal.seq = list_entry(list->prev,
+ struct journal_replay,
+ list)->j.seq;
+
+ return 0;
+#undef read_bucket
+}
+
+void bch_journal_mark(struct cache_set *c, struct list_head *list)
+{
+ atomic_t p = { 0 };
+ struct bkey *k;
+ struct journal_replay *i;
+ struct journal *j = &c->journal;
+ uint64_t last = j->seq;
+
+ /*
+ * journal.pin should never fill up - we never write a journal
+ * entry when it would fill up. But if for some reason it does, we
+ * iterate over the list in reverse order so that we can just skip that
+ * refcount instead of bugging.
+ */
+
+ list_for_each_entry_reverse(i, list, list) {
+ BUG_ON(last < i->j.seq);
+ i->pin = NULL;
+
+ while (last-- != i->j.seq)
+ if (fifo_free(&j->pin) > 1) {
+ fifo_push_front(&j->pin, p);
+ atomic_set(&fifo_front(&j->pin), 0);
+ }
+
+ if (fifo_free(&j->pin) > 1) {
+ fifo_push_front(&j->pin, p);
+ i->pin = &fifo_front(&j->pin);
+ atomic_set(i->pin, 1);
+ }
+
+ for (k = i->j.start;
+ k < end(&i->j);
+ k = bkey_next(k)) {
+ unsigned j;
+
+ for (j = 0; j < KEY_PTRS(k); j++) {
+ struct bucket *g = PTR_BUCKET(c, k, j);
+ atomic_inc(&g->pin);
+
+ if (g->prio == BTREE_PRIO &&
+ !ptr_stale(c, k, j))
+ g->prio = INITIAL_PRIO;
+ }
+
+ __bch_btree_mark_key(c, 0, k);
+ }
+ }
+}
+
+int bch_journal_replay(struct cache_set *s, struct list_head *list,
+ struct btree_op *op)
+{
+ int ret = 0, keys = 0, entries = 0;
+ struct bkey *k;
+ struct journal_replay *i =
+ list_entry(list->prev, struct journal_replay, list);
+
+ uint64_t start = i->j.last_seq, end = i->j.seq, n = start;
+
+ list_for_each_entry(i, list, list) {
+ BUG_ON(i->pin && atomic_read(i->pin) != 1);
+
+ if (n != i->j.seq)
+ pr_err("journal entries %llu-%llu "
+ "missing! (replaying %llu-%llu)\n",
+ n, i->j.seq - 1, start, end);
+
+ for (k = i->j.start;
+ k < end(&i->j);
+ k = bkey_next(k)) {
+ pr_debug("%s", pkey(k));
+ bkey_copy(op->keys.top, k);
+ bch_keylist_push(&op->keys);
+
+ op->journal = i->pin;
+ atomic_inc(op->journal);
+
+ ret = bch_btree_insert(op, s);
+ if (ret)
+ goto err;
+
+ BUG_ON(!bch_keylist_empty(&op->keys));
+ keys++;
+
+ cond_resched();
+ }
+
+ if (i->pin)
+ atomic_dec(i->pin);
+ n = i->j.seq + 1;
+ entries++;
+ }
+
+ pr_info("journal replay done, %i keys in %i entries, seq %llu",
+ keys, entries, end);
+
+ while (!list_empty(list)) {
+ i = list_first_entry(list, struct journal_replay, list);
+ list_del(&i->list);
+ kfree(i);
+ }
+err:
+ closure_sync(&op->cl);
+ return ret;
+}
+
+/* Journalling */
+
+static void btree_flush_write(struct cache_set *c)
+{
+ /*
+ * Try to find the btree node with that references the oldest journal
+ * entry, best is our current candidate and is locked if non NULL:
+ */
+ struct btree *b, *best = NULL;
+ unsigned iter;
+
+ for_each_cached_btree(b, c, iter) {
+ if (!down_write_trylock(&b->lock))
+ continue;
+
+ if (!btree_node_dirty(b) ||
+ !btree_current_write(b)->journal) {
+ rw_unlock(true, b);
+ continue;
+ }
+
+ if (!best)
+ best = b;
+ else if (journal_pin_cmp(c,
+ btree_current_write(best),
+ btree_current_write(b))) {
+ rw_unlock(true, best);
+ best = b;
+ } else
+ rw_unlock(true, b);
+ }
+
+ if (best)
+ goto out;
+
+ /* We can't find the best btree node, just pick the first */
+ list_for_each_entry(b, &c->btree_cache, list)
+ if (!b->level && btree_node_dirty(b)) {
+ best = b;
+ rw_lock(true, best, best->level);
+ goto found;
+ }
+
+out:
+ if (!best)
+ return;
+found:
+ if (btree_node_dirty(best))
+ bch_btree_write(best, true, NULL);
+ rw_unlock(true, best);
+}
+
+#define last_seq(j) ((j)->seq - fifo_used(&(j)->pin) + 1)
+
+static void journal_discard_endio(struct bio *bio, int error)
+{
+ struct journal_device *ja =
+ container_of(bio, struct journal_device, discard_bio);
+ struct cache *ca = container_of(ja, struct cache, journal);
+
+ atomic_set(&ja->discard_in_flight, DISCARD_DONE);
+
+ closure_wake_up(&ca->set->journal.wait);
+ closure_put(&ca->set->cl);
+}
+
+static void journal_discard_work(struct work_struct *work)
+{
+ struct journal_device *ja =
+ container_of(work, struct journal_device, discard_work);
+
+ submit_bio(0, &ja->discard_bio);
+}
+
+static void do_journal_discard(struct cache *ca)
+{
+ struct journal_device *ja = &ca->journal;
+ struct bio *bio = &ja->discard_bio;
+
+ if (!ca->discard) {
+ ja->discard_idx = ja->last_idx;
+ return;
+ }
+
+ switch (atomic_read(&ja->discard_in_flight) == DISCARD_IN_FLIGHT) {
+ case DISCARD_IN_FLIGHT:
+ return;
+
+ case DISCARD_DONE:
+ ja->discard_idx = (ja->discard_idx + 1) %
+ ca->sb.njournal_buckets;
+
+ atomic_set(&ja->discard_in_flight, DISCARD_READY);
+ /* fallthrough */
+
+ case DISCARD_READY:
+ if (ja->discard_idx == ja->last_idx)
+ return;
+
+ atomic_set(&ja->discard_in_flight, DISCARD_IN_FLIGHT);
+
+ bio_init(bio);
+ bio->bi_sector = bucket_to_sector(ca->set,
+ ca->sb.d[ja->discard_idx]);
+ bio->bi_bdev = ca->bdev;
+ bio->bi_rw = REQ_WRITE|REQ_DISCARD;
+ bio->bi_max_vecs = 1;
+ bio->bi_io_vec = bio->bi_inline_vecs;
+ bio->bi_size = bucket_bytes(ca);
+ bio->bi_end_io = journal_discard_endio;
+
+ closure_get(&ca->set->cl);
+ INIT_WORK(&ja->discard_work, journal_discard_work);
+ schedule_work(&ja->discard_work);
+ }
+}
+
+static void journal_reclaim(struct cache_set *c)
+{
+ struct bkey *k = &c->journal.key;
+ struct cache *ca;
+ uint64_t last_seq;
+ unsigned iter, n = 0;
+ atomic_t p;
+
+ while (!atomic_read(&fifo_front(&c->journal.pin)))
+ fifo_pop(&c->journal.pin, p);
+
+ last_seq = last_seq(&c->journal);
+
+ /* Update last_idx */
+
+ for_each_cache(ca, c, iter) {
+ struct journal_device *ja = &ca->journal;
+
+ while (ja->last_idx != ja->cur_idx &&
+ ja->seq[ja->last_idx] < last_seq)
+ ja->last_idx = (ja->last_idx + 1) %
+ ca->sb.njournal_buckets;
+ }
+
+ for_each_cache(ca, c, iter)
+ do_journal_discard(ca);
+
+ if (c->journal.blocks_free)
+ return;
+
+ /*
+ * Allocate:
+ * XXX: Sort by free journal space
+ */
+
+ for_each_cache(ca, c, iter) {
+ struct journal_device *ja = &ca->journal;
+ unsigned next = (ja->cur_idx + 1) % ca->sb.njournal_buckets;
+
+ /* No space available on this device */
+ if (next == ja->discard_idx)
+ continue;
+
+ ja->cur_idx = next;
+ k->ptr[n++] = PTR(0,
+ bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
+ ca->sb.nr_this_dev);
+ }
+
+ bkey_init(k);
+ SET_KEY_PTRS(k, n);
+
+ if (n)
+ c->journal.blocks_free = c->sb.bucket_size >> c->block_bits;
+
+ if (!journal_full(&c->journal))
+ __closure_wake_up(&c->journal.wait);
+}
+
+void bch_journal_next(struct journal *j)
+{
+ atomic_t p = { 1 };
+
+ j->cur = (j->cur == j->w)
+ ? &j->w[1]
+ : &j->w[0];
+
+ /*
+ * The fifo_push() needs to happen at the same time as j->seq is
+ * incremented for last_seq() to be calculated correctly
+ */
+ BUG_ON(!fifo_push(&j->pin, p));
+ atomic_set(&fifo_back(&j->pin), 1);
+
+ j->cur->data->seq = ++j->seq;
+ j->cur->need_write = false;
+ j->cur->data->keys = 0;
+
+ if (fifo_full(&j->pin))
+ pr_debug("journal_pin full (%zu)", fifo_used(&j->pin));
+}
+
+static void journal_write_endio(struct bio *bio, int error)
+{
+ struct journal_write *w = bio->bi_private;
+
+ cache_set_err_on(error, w->c, "journal io error");
+ closure_put(&w->c->journal.io.cl);
+}
+
+static void journal_write(struct closure *);
+
+static void journal_write_done(struct closure *cl)
+{
+ struct journal *j = container_of(cl, struct journal, io.cl);
+ struct cache_set *c = container_of(j, struct cache_set, journal);
+
+ struct journal_write *w = (j->cur == j->w)
+ ? &j->w[1]
+ : &j->w[0];
+
+ __closure_wake_up(&w->wait);
+
+ if (c->journal_delay_ms)
+ closure_delay(&j->io, msecs_to_jiffies(c->journal_delay_ms));
+
+ continue_at(cl, journal_write, system_wq);
+}
+
+static void journal_write_unlocked(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, journal.io.cl);
+ struct cache *ca;
+ struct journal_write *w = c->journal.cur;
+ struct bkey *k = &c->journal.key;
+ unsigned i, sectors = set_blocks(w->data, c) * c->sb.block_size;
+
+ struct bio *bio;
+ struct bio_list list;
+ bio_list_init(&list);
+
+ if (!w->need_write) {
+ /*
+ * XXX: have to unlock closure before we unlock journal lock,
+ * else we race with bch_journal(). But this way we race
+ * against cache set unregister. Doh.
+ */
+ set_closure_fn(cl, NULL, NULL);
+ closure_sub(cl, CLOSURE_RUNNING + 1);
+ spin_unlock(&c->journal.lock);
+ return;
+ } else if (journal_full(&c->journal)) {
+ journal_reclaim(c);
+ spin_unlock(&c->journal.lock);
+
+ btree_flush_write(c);
+ continue_at(cl, journal_write, system_wq);
+ }
+
+ c->journal.blocks_free -= set_blocks(w->data, c);
+
+ w->data->btree_level = c->root->level;
+
+ bkey_copy(&w->data->btree_root, &c->root->key);
+ bkey_copy(&w->data->uuid_bucket, &c->uuid_bucket);
+
+ for_each_cache(ca, c, i)
+ w->data->prio_bucket[ca->sb.nr_this_dev] = ca->prio_buckets[0];
+
+ w->data->magic = jset_magic(c);
+ w->data->version = BCACHE_JSET_VERSION;
+ w->data->last_seq = last_seq(&c->journal);
+ w->data->csum = csum_set(w->data);
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ ca = PTR_CACHE(c, k, i);
+ bio = &ca->journal.bio;
+
+ atomic_long_add(sectors, &ca->meta_sectors_written);
+
+ bio_reset(bio);
+ bio->bi_sector = PTR_OFFSET(k, i);
+ bio->bi_bdev = ca->bdev;
+ bio->bi_rw = REQ_WRITE|REQ_SYNC|REQ_META|REQ_FLUSH;
+ bio->bi_size = sectors << 9;
+
+ bio->bi_end_io = journal_write_endio;
+ bio->bi_private = w;
+ bio_map(bio, w->data);
+
+ trace_bcache_journal_write(bio);
+ bio_list_add(&list, bio);
+
+ SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + sectors);
+
+ ca->journal.seq[ca->journal.cur_idx] = w->data->seq;
+ }
+
+ atomic_dec_bug(&fifo_back(&c->journal.pin));
+ bch_journal_next(&c->journal);
+ journal_reclaim(c);
+
+ spin_unlock(&c->journal.lock);
+
+ while ((bio = bio_list_pop(&list)))
+ closure_bio_submit(bio, cl, c->cache[0]);
+
+ continue_at(cl, journal_write_done, NULL);
+}
+
+static void journal_write(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, journal.io.cl);
+
+ spin_lock(&c->journal.lock);
+ journal_write_unlocked(cl);
+}
+
+static void __journal_try_write(struct cache_set *c, bool noflush)
+{
+ struct closure *cl = &c->journal.io.cl;
+
+ if (!closure_trylock(cl, &c->cl))
+ spin_unlock(&c->journal.lock);
+ else if (noflush && journal_full(&c->journal)) {
+ spin_unlock(&c->journal.lock);
+ continue_at(cl, journal_write, system_wq);
+ } else
+ journal_write_unlocked(cl);
+}
+
+#define journal_try_write(c) __journal_try_write(c, false)
+
+void bch_journal_meta(struct cache_set *c, struct closure *cl)
+{
+ struct journal_write *w;
+
+ if (CACHE_SYNC(&c->sb)) {
+ spin_lock(&c->journal.lock);
+
+ w = c->journal.cur;
+ w->need_write = true;
+
+ if (cl)
+ BUG_ON(!closure_wait(&w->wait, cl));
+
+ __journal_try_write(c, true);
+ }
+}
+
+/*
+ * Entry point to the journalling code - bio_insert() and btree_invalidate()
+ * pass bch_journal() a list of keys to be journalled, and then
+ * bch_journal() hands those same keys off to btree_insert_async()
+ */
+
+void bch_journal(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+ struct cache_set *c = op->c;
+ struct journal_write *w;
+ size_t b, n = ((uint64_t *) op->keys.top) - op->keys.list;
+
+ if (op->type != BTREE_INSERT ||
+ !CACHE_SYNC(&c->sb))
+ goto out;
+
+ /*
+ * If we're looping because we errored, might already be waiting on
+ * another journal write:
+ */
+ while (atomic_read(&cl->parent->remaining) & CLOSURE_WAITING)
+ closure_sync(cl->parent);
+
+ spin_lock(&c->journal.lock);
+
+ if (journal_full(&c->journal)) {
+ /* XXX: tracepoint */
+ closure_wait(&c->journal.wait, cl);
+
+ journal_reclaim(c);
+ spin_unlock(&c->journal.lock);
+
+ btree_flush_write(c);
+ continue_at(cl, bch_journal, bcache_wq);
+ }
+
+ w = c->journal.cur;
+ w->need_write = true;
+ b = __set_blocks(w->data, w->data->keys + n, c);
+
+ if (b * c->sb.block_size > PAGE_SECTORS << JSET_BITS ||
+ b > c->journal.blocks_free) {
+ /* XXX: If we were inserting so many keys that they won't fit in
+ * an _empty_ journal write, we'll deadlock. For now, handle
+ * this in bch_keylist_realloc() - but something to think about.
+ */
+ BUG_ON(!w->data->keys);
+
+ /* XXX: tracepoint */
+ BUG_ON(!closure_wait(&w->wait, cl));
+
+ closure_flush(&c->journal.io);
+
+ journal_try_write(c);
+ continue_at(cl, bch_journal, bcache_wq);
+ }
+
+ memcpy(end(w->data), op->keys.list, n * sizeof(uint64_t));
+ w->data->keys += n;
+
+ op->journal = &fifo_back(&c->journal.pin);
+ atomic_inc(op->journal);
+
+ if (op->flush_journal) {
+ closure_flush(&c->journal.io);
+ closure_wait(&w->wait, cl->parent);
+ }
+
+ journal_try_write(c);
+out:
+ bch_btree_insert_async(cl);
+}
+
+void bch_journal_free(struct cache_set *c)
+{
+ free_pages((unsigned long) c->journal.w[1].data, JSET_BITS);
+ free_pages((unsigned long) c->journal.w[0].data, JSET_BITS);
+ free_fifo(&c->journal.pin);
+}
+
+int bch_journal_alloc(struct cache_set *c)
+{
+ struct journal *j = &c->journal;
+
+ closure_init_unlocked(&j->io);
+ spin_lock_init(&j->lock);
+
+ c->journal_delay_ms = 100;
+
+ j->w[0].c = c;
+ j->w[1].c = c;
+
+ if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
+ !(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)) ||
+ !(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)))
+ return -ENOMEM;
+
+ return 0;
+}
--- /dev/null
+#ifndef _BCACHE_JOURNAL_H
+#define _BCACHE_JOURNAL_H
+
+/*
+ * THE JOURNAL:
+ *
+ * The journal is treated as a circular buffer of buckets - a journal entry
+ * never spans two buckets. This means (not implemented yet) we can resize the
+ * journal at runtime, and will be needed for bcache on raw flash support.
+ *
+ * Journal entries contain a list of keys, ordered by the time they were
+ * inserted; thus journal replay just has to reinsert the keys.
+ *
+ * We also keep some things in the journal header that are logically part of the
+ * superblock - all the things that are frequently updated. This is for future
+ * bcache on raw flash support; the superblock (which will become another
+ * journal) can't be moved or wear leveled, so it contains just enough
+ * information to find the main journal, and the superblock only has to be
+ * rewritten when we want to move/wear level the main journal.
+ *
+ * Currently, we don't journal BTREE_REPLACE operations - this will hopefully be
+ * fixed eventually. This isn't a bug - BTREE_REPLACE is used for insertions
+ * from cache misses, which don't have to be journaled, and for writeback and
+ * moving gc we work around it by flushing the btree to disk before updating the
+ * gc information. But it is a potential issue with incremental garbage
+ * collection, and it's fragile.
+ *
+ * OPEN JOURNAL ENTRIES:
+ *
+ * Each journal entry contains, in the header, the sequence number of the last
+ * journal entry still open - i.e. that has keys that haven't been flushed to
+ * disk in the btree.
+ *
+ * We track this by maintaining a refcount for every open journal entry, in a
+ * fifo; each entry in the fifo corresponds to a particular journal
+ * entry/sequence number. When the refcount at the tail of the fifo goes to
+ * zero, we pop it off - thus, the size of the fifo tells us the number of open
+ * journal entries
+ *
+ * We take a refcount on a journal entry when we add some keys to a journal
+ * entry that we're going to insert (held by struct btree_op), and then when we
+ * insert those keys into the btree the btree write we're setting up takes a
+ * copy of that refcount (held by struct btree_write). That refcount is dropped
+ * when the btree write completes.
+ *
+ * A struct btree_write can only hold a refcount on a single journal entry, but
+ * might contain keys for many journal entries - we handle this by making sure
+ * it always has a refcount on the _oldest_ journal entry of all the journal
+ * entries it has keys for.
+ *
+ * JOURNAL RECLAIM:
+ *
+ * As mentioned previously, our fifo of refcounts tells us the number of open
+ * journal entries; from that and the current journal sequence number we compute
+ * last_seq - the oldest journal entry we still need. We write last_seq in each
+ * journal entry, and we also have to keep track of where it exists on disk so
+ * we don't overwrite it when we loop around the journal.
+ *
+ * To do that we track, for each journal bucket, the sequence number of the
+ * newest journal entry it contains - if we don't need that journal entry we
+ * don't need anything in that bucket anymore. From that we track the last
+ * journal bucket we still need; all this is tracked in struct journal_device
+ * and updated by journal_reclaim().
+ *
+ * JOURNAL FILLING UP:
+ *
+ * There are two ways the journal could fill up; either we could run out of
+ * space to write to, or we could have too many open journal entries and run out
+ * of room in the fifo of refcounts. Since those refcounts are decremented
+ * without any locking we can't safely resize that fifo, so we handle it the
+ * same way.
+ *
+ * If the journal fills up, we start flushing dirty btree nodes until we can
+ * allocate space for a journal write again - preferentially flushing btree
+ * nodes that are pinning the oldest journal entries first.
+ */
+
+#define BCACHE_JSET_VERSION_UUIDv1 1
+/* Always latest UUID format */
+#define BCACHE_JSET_VERSION_UUID 1
+#define BCACHE_JSET_VERSION 1
+
+/*
+ * On disk format for a journal entry:
+ * seq is monotonically increasing; every journal entry has its own unique
+ * sequence number.
+ *
+ * last_seq is the oldest journal entry that still has keys the btree hasn't
+ * flushed to disk yet.
+ *
+ * version is for on disk format changes.
+ */
+struct jset {
+ uint64_t csum;
+ uint64_t magic;
+ uint64_t seq;
+ uint32_t version;
+ uint32_t keys;
+
+ uint64_t last_seq;
+
+ BKEY_PADDED(uuid_bucket);
+ BKEY_PADDED(btree_root);
+ uint16_t btree_level;
+ uint16_t pad[3];
+
+ uint64_t prio_bucket[MAX_CACHES_PER_SET];
+
+ union {
+ struct bkey start[0];
+ uint64_t d[0];
+ };
+};
+
+/*
+ * Only used for holding the journal entries we read in btree_journal_read()
+ * during cache_registration
+ */
+struct journal_replay {
+ struct list_head list;
+ atomic_t *pin;
+ struct jset j;
+};
+
+/*
+ * We put two of these in struct journal; we used them for writes to the
+ * journal that are being staged or in flight.
+ */
+struct journal_write {
+ struct jset *data;
+#define JSET_BITS 3
+
+ struct cache_set *c;
+ struct closure_waitlist wait;
+ bool need_write;
+};
+
+/* Embedded in struct cache_set */
+struct journal {
+ spinlock_t lock;
+ /* used when waiting because the journal was full */
+ struct closure_waitlist wait;
+ struct closure_with_timer io;
+
+ /* Number of blocks free in the bucket(s) we're currently writing to */
+ unsigned blocks_free;
+ uint64_t seq;
+ DECLARE_FIFO(atomic_t, pin);
+
+ BKEY_PADDED(key);
+
+ struct journal_write w[2], *cur;
+};
+
+/*
+ * Embedded in struct cache. First three fields refer to the array of journal
+ * buckets, in cache_sb.
+ */
+struct journal_device {
+ /*
+ * For each journal bucket, contains the max sequence number of the
+ * journal writes it contains - so we know when a bucket can be reused.
+ */
+ uint64_t seq[SB_JOURNAL_BUCKETS];
+
+ /* Journal bucket we're currently writing to */
+ unsigned cur_idx;
+
+ /* Last journal bucket that still contains an open journal entry */
+ unsigned last_idx;
+
+ /* Next journal bucket to be discarded */
+ unsigned discard_idx;
+
+#define DISCARD_READY 0
+#define DISCARD_IN_FLIGHT 1
+#define DISCARD_DONE 2
+ /* 1 - discard in flight, -1 - discard completed */
+ atomic_t discard_in_flight;
+
+ struct work_struct discard_work;
+ struct bio discard_bio;
+ struct bio_vec discard_bv;
+
+ /* Bio for journal reads/writes to this device */
+ struct bio bio;
+ struct bio_vec bv[8];
+};
+
+#define journal_pin_cmp(c, l, r) \
+ (fifo_idx(&(c)->journal.pin, (l)->journal) > \
+ fifo_idx(&(c)->journal.pin, (r)->journal))
+
+#define JOURNAL_PIN 20000
+
+#define journal_full(j) \
+ (!(j)->blocks_free || fifo_free(&(j)->pin) <= 1)
+
+struct closure;
+struct cache_set;
+struct btree_op;
+
+void bch_journal(struct closure *);
+void bch_journal_next(struct journal *);
+void bch_journal_mark(struct cache_set *, struct list_head *);
+void bch_journal_meta(struct cache_set *, struct closure *);
+int bch_journal_read(struct cache_set *, struct list_head *,
+ struct btree_op *);
+int bch_journal_replay(struct cache_set *, struct list_head *,
+ struct btree_op *);
+
+void bch_journal_free(struct cache_set *);
+int bch_journal_alloc(struct cache_set *);
+
+#endif /* _BCACHE_JOURNAL_H */
--- /dev/null
+/*
+ * Moving/copying garbage collector
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+struct moving_io {
+ struct keybuf_key *w;
+ struct search s;
+ struct bbio bio;
+};
+
+static bool moving_pred(struct keybuf *buf, struct bkey *k)
+{
+ struct cache_set *c = container_of(buf, struct cache_set,
+ moving_gc_keys);
+ unsigned i;
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ struct cache *ca = PTR_CACHE(c, k, i);
+ struct bucket *g = PTR_BUCKET(c, k, i);
+
+ if (GC_SECTORS_USED(g) < ca->gc_move_threshold)
+ return true;
+ }
+
+ return false;
+}
+
+/* Moving GC - IO loop */
+
+static void moving_io_destructor(struct closure *cl)
+{
+ struct moving_io *io = container_of(cl, struct moving_io, s.cl);
+ kfree(io);
+}
+
+static void write_moving_finish(struct closure *cl)
+{
+ struct moving_io *io = container_of(cl, struct moving_io, s.cl);
+ struct bio *bio = &io->bio.bio;
+ struct bio_vec *bv = bio_iovec_idx(bio, bio->bi_vcnt);
+
+ while (bv-- != bio->bi_io_vec)
+ __free_page(bv->bv_page);
+
+ pr_debug("%s %s", io->s.op.insert_collision
+ ? "collision moving" : "moved",
+ pkey(&io->w->key));
+
+ bch_keybuf_del(&io->s.op.c->moving_gc_keys, io->w);
+
+ atomic_dec_bug(&io->s.op.c->in_flight);
+ closure_wake_up(&io->s.op.c->moving_gc_wait);
+
+ closure_return_with_destructor(cl, moving_io_destructor);
+}
+
+static void read_moving_endio(struct bio *bio, int error)
+{
+ struct moving_io *io = container_of(bio->bi_private,
+ struct moving_io, s.cl);
+
+ if (error)
+ io->s.error = error;
+
+ bch_bbio_endio(io->s.op.c, bio, error, "reading data to move");
+}
+
+static void moving_init(struct moving_io *io)
+{
+ struct bio *bio = &io->bio.bio;
+
+ bio_init(bio);
+ bio_get(bio);
+ bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+
+ bio->bi_size = KEY_SIZE(&io->w->key) << 9;
+ bio->bi_max_vecs = DIV_ROUND_UP(KEY_SIZE(&io->w->key),
+ PAGE_SECTORS);
+ bio->bi_private = &io->s.cl;
+ bio->bi_io_vec = bio->bi_inline_vecs;
+ bio_map(bio, NULL);
+}
+
+static void write_moving(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct moving_io *io = container_of(s, struct moving_io, s);
+
+ if (!s->error) {
+ trace_bcache_write_moving(&io->bio.bio);
+
+ moving_init(io);
+
+ io->bio.bio.bi_sector = KEY_START(&io->w->key);
+ s->op.lock = -1;
+ s->op.write_prio = 1;
+ s->op.cache_bio = &io->bio.bio;
+
+ s->writeback = KEY_DIRTY(&io->w->key);
+ s->op.csum = KEY_CSUM(&io->w->key);
+
+ s->op.type = BTREE_REPLACE;
+ bkey_copy(&s->op.replace, &io->w->key);
+
+ closure_init(&s->op.cl, cl);
+ bch_insert_data(&s->op.cl);
+ }
+
+ continue_at(cl, write_moving_finish, NULL);
+}
+
+static void read_moving_submit(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct moving_io *io = container_of(s, struct moving_io, s);
+ struct bio *bio = &io->bio.bio;
+
+ trace_bcache_read_moving(bio);
+ bch_submit_bbio(bio, s->op.c, &io->w->key, 0);
+
+ continue_at(cl, write_moving, bch_gc_wq);
+}
+
+static void read_moving(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, moving_gc);
+ struct keybuf_key *w;
+ struct moving_io *io;
+ struct bio *bio;
+
+ /* XXX: if we error, background writeback could stall indefinitely */
+
+ while (!test_bit(CACHE_SET_STOPPING, &c->flags)) {
+ w = bch_keybuf_next_rescan(c, &c->moving_gc_keys, &MAX_KEY);
+ if (!w)
+ break;
+
+ io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec)
+ * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS),
+ GFP_KERNEL);
+ if (!io)
+ goto err;
+
+ w->private = io;
+ io->w = w;
+ io->s.op.inode = KEY_INODE(&w->key);
+ io->s.op.c = c;
+
+ moving_init(io);
+ bio = &io->bio.bio;
+
+ bio->bi_rw = READ;
+ bio->bi_end_io = read_moving_endio;
+
+ if (bio_alloc_pages(bio, GFP_KERNEL))
+ goto err;
+
+ pr_debug("%s", pkey(&w->key));
+
+ closure_call(&io->s.cl, read_moving_submit, NULL, &c->gc.cl);
+
+ if (atomic_inc_return(&c->in_flight) >= 64) {
+ closure_wait_event(&c->moving_gc_wait, cl,
+ atomic_read(&c->in_flight) < 64);
+ continue_at(cl, read_moving, bch_gc_wq);
+ }
+ }
+
+ if (0) {
+err: if (!IS_ERR_OR_NULL(w->private))
+ kfree(w->private);
+
+ bch_keybuf_del(&c->moving_gc_keys, w);
+ }
+
+ closure_return(cl);
+}
+
+void bch_moving_gc(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, gc.cl);
+ struct cache *ca;
+ struct bucket *b;
+ unsigned i;
+
+ bool bucket_cmp(struct bucket *l, struct bucket *r)
+ {
+ return GC_SECTORS_USED(l) < GC_SECTORS_USED(r);
+ }
+
+ unsigned top(struct cache *ca)
+ {
+ return GC_SECTORS_USED(heap_peek(&ca->heap));
+ }
+
+ if (!c->copy_gc_enabled)
+ closure_return(cl);
+
+ mutex_lock(&c->bucket_lock);
+
+ for_each_cache(ca, c, i) {
+ unsigned sectors_to_move = 0;
+ unsigned reserve_sectors = ca->sb.bucket_size *
+ min(fifo_used(&ca->free), ca->free.size / 2);
+
+ ca->heap.used = 0;
+
+ for_each_bucket(b, ca) {
+ if (!GC_SECTORS_USED(b))
+ continue;
+
+ if (!heap_full(&ca->heap)) {
+ sectors_to_move += GC_SECTORS_USED(b);
+ heap_add(&ca->heap, b, bucket_cmp);
+ } else if (bucket_cmp(b, heap_peek(&ca->heap))) {
+ sectors_to_move -= top(ca);
+ sectors_to_move += GC_SECTORS_USED(b);
+
+ ca->heap.data[0] = b;
+ heap_sift(&ca->heap, 0, bucket_cmp);
+ }
+ }
+
+ while (sectors_to_move > reserve_sectors) {
+ heap_pop(&ca->heap, b, bucket_cmp);
+ sectors_to_move -= GC_SECTORS_USED(b);
+ }
+
+ ca->gc_move_threshold = top(ca);
+
+ pr_debug("threshold %u", ca->gc_move_threshold);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+
+ c->moving_gc_keys.last_scanned = ZERO_KEY;
+
+ closure_init(&c->moving_gc, cl);
+ read_moving(&c->moving_gc);
+
+ closure_return(cl);
+}
+
+void bch_moving_init_cache_set(struct cache_set *c)
+{
+ bch_keybuf_init(&c->moving_gc_keys, moving_pred);
+}
--- /dev/null
+/*
+ * Main bcache entry point - handle a read or a write request and decide what to
+ * do with it; the make_request functions are called by the block layer.
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+#include <linux/cgroup.h>
+#include <linux/module.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include "blk-cgroup.h"
+
+#include <trace/events/bcache.h>
+
+#define CUTOFF_CACHE_ADD 95
+#define CUTOFF_CACHE_READA 90
+#define CUTOFF_WRITEBACK 50
+#define CUTOFF_WRITEBACK_SYNC 75
+
+struct kmem_cache *bch_search_cache;
+
+static void check_should_skip(struct cached_dev *, struct search *);
+
+/* Cgroup interface */
+
+#ifdef CONFIG_CGROUP_BCACHE
+static struct bch_cgroup bcache_default_cgroup = { .cache_mode = -1 };
+
+static struct bch_cgroup *cgroup_to_bcache(struct cgroup *cgroup)
+{
+ struct cgroup_subsys_state *css;
+ return cgroup &&
+ (css = cgroup_subsys_state(cgroup, bcache_subsys_id))
+ ? container_of(css, struct bch_cgroup, css)
+ : &bcache_default_cgroup;
+}
+
+struct bch_cgroup *bch_bio_to_cgroup(struct bio *bio)
+{
+ struct cgroup_subsys_state *css = bio->bi_css
+ ? cgroup_subsys_state(bio->bi_css->cgroup, bcache_subsys_id)
+ : task_subsys_state(current, bcache_subsys_id);
+
+ return css
+ ? container_of(css, struct bch_cgroup, css)
+ : &bcache_default_cgroup;
+}
+
+static ssize_t cache_mode_read(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ char __user *buf, size_t nbytes, loff_t *ppos)
+{
+ char tmp[1024];
+ int len = snprint_string_list(tmp, PAGE_SIZE, bch_cache_modes,
+ cgroup_to_bcache(cgrp)->cache_mode + 1);
+
+ if (len < 0)
+ return len;
+
+ return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
+}
+
+static int cache_mode_write(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ int v = read_string_list(buf, bch_cache_modes);
+ if (v < 0)
+ return v;
+
+ cgroup_to_bcache(cgrp)->cache_mode = v - 1;
+ return 0;
+}
+
+static u64 bch_verify_read(struct cgroup *cgrp, struct cftype *cft)
+{
+ return cgroup_to_bcache(cgrp)->verify;
+}
+
+static int bch_verify_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+ cgroup_to_bcache(cgrp)->verify = val;
+ return 0;
+}
+
+static u64 bch_cache_hits_read(struct cgroup *cgrp, struct cftype *cft)
+{
+ struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
+ return atomic_read(&bcachecg->stats.cache_hits);
+}
+
+static u64 bch_cache_misses_read(struct cgroup *cgrp, struct cftype *cft)
+{
+ struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
+ return atomic_read(&bcachecg->stats.cache_misses);
+}
+
+static u64 bch_cache_bypass_hits_read(struct cgroup *cgrp,
+ struct cftype *cft)
+{
+ struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
+ return atomic_read(&bcachecg->stats.cache_bypass_hits);
+}
+
+static u64 bch_cache_bypass_misses_read(struct cgroup *cgrp,
+ struct cftype *cft)
+{
+ struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp);
+ return atomic_read(&bcachecg->stats.cache_bypass_misses);
+}
+
+static struct cftype bch_files[] = {
+ {
+ .name = "cache_mode",
+ .read = cache_mode_read,
+ .write_string = cache_mode_write,
+ },
+ {
+ .name = "verify",
+ .read_u64 = bch_verify_read,
+ .write_u64 = bch_verify_write,
+ },
+ {
+ .name = "cache_hits",
+ .read_u64 = bch_cache_hits_read,
+ },
+ {
+ .name = "cache_misses",
+ .read_u64 = bch_cache_misses_read,
+ },
+ {
+ .name = "cache_bypass_hits",
+ .read_u64 = bch_cache_bypass_hits_read,
+ },
+ {
+ .name = "cache_bypass_misses",
+ .read_u64 = bch_cache_bypass_misses_read,
+ },
+ { } /* terminate */
+};
+
+static void init_bch_cgroup(struct bch_cgroup *cg)
+{
+ cg->cache_mode = -1;
+}
+
+static struct cgroup_subsys_state *bcachecg_create(struct cgroup *cgroup)
+{
+ struct bch_cgroup *cg;
+
+ cg = kzalloc(sizeof(*cg), GFP_KERNEL);
+ if (!cg)
+ return ERR_PTR(-ENOMEM);
+ init_bch_cgroup(cg);
+ return &cg->css;
+}
+
+static void bcachecg_destroy(struct cgroup *cgroup)
+{
+ struct bch_cgroup *cg = cgroup_to_bcache(cgroup);
+ free_css_id(&bcache_subsys, &cg->css);
+ kfree(cg);
+}
+
+struct cgroup_subsys bcache_subsys = {
+ .create = bcachecg_create,
+ .destroy = bcachecg_destroy,
+ .subsys_id = bcache_subsys_id,
+ .name = "bcache",
+ .module = THIS_MODULE,
+};
+EXPORT_SYMBOL_GPL(bcache_subsys);
+#endif
+
+static unsigned cache_mode(struct cached_dev *dc, struct bio *bio)
+{
+#ifdef CONFIG_CGROUP_BCACHE
+ int r = bch_bio_to_cgroup(bio)->cache_mode;
+ if (r >= 0)
+ return r;
+#endif
+ return BDEV_CACHE_MODE(&dc->sb);
+}
+
+static bool verify(struct cached_dev *dc, struct bio *bio)
+{
+#ifdef CONFIG_CGROUP_BCACHE
+ if (bch_bio_to_cgroup(bio)->verify)
+ return true;
+#endif
+ return dc->verify;
+}
+
+static void bio_csum(struct bio *bio, struct bkey *k)
+{
+ struct bio_vec *bv;
+ uint64_t csum = 0;
+ int i;
+
+ bio_for_each_segment(bv, bio, i) {
+ void *d = kmap(bv->bv_page) + bv->bv_offset;
+ csum = crc64_update(csum, d, bv->bv_len);
+ kunmap(bv->bv_page);
+ }
+
+ k->ptr[KEY_PTRS(k)] = csum & (~0ULL >> 1);
+}
+
+/* Insert data into cache */
+
+static void bio_invalidate(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+ struct bio *bio = op->cache_bio;
+
+ pr_debug("invalidating %i sectors from %llu",
+ bio_sectors(bio), (uint64_t) bio->bi_sector);
+
+ while (bio_sectors(bio)) {
+ unsigned len = min(bio_sectors(bio), 1U << 14);
+
+ if (bch_keylist_realloc(&op->keys, 0, op->c))
+ goto out;
+
+ bio->bi_sector += len;
+ bio->bi_size -= len << 9;
+
+ bch_keylist_add(&op->keys,
+ &KEY(op->inode, bio->bi_sector, len));
+ }
+
+ op->insert_data_done = true;
+ bio_put(bio);
+out:
+ continue_at(cl, bch_journal, bcache_wq);
+}
+
+struct open_bucket {
+ struct list_head list;
+ struct task_struct *last;
+ unsigned sectors_free;
+ BKEY_PADDED(key);
+};
+
+void bch_open_buckets_free(struct cache_set *c)
+{
+ struct open_bucket *b;
+
+ while (!list_empty(&c->data_buckets)) {
+ b = list_first_entry(&c->data_buckets,
+ struct open_bucket, list);
+ list_del(&b->list);
+ kfree(b);
+ }
+}
+
+int bch_open_buckets_alloc(struct cache_set *c)
+{
+ int i;
+
+ spin_lock_init(&c->data_bucket_lock);
+
+ for (i = 0; i < 6; i++) {
+ struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL);
+ if (!b)
+ return -ENOMEM;
+
+ list_add(&b->list, &c->data_buckets);
+ }
+
+ return 0;
+}
+
+/*
+ * We keep multiple buckets open for writes, and try to segregate different
+ * write streams for better cache utilization: first we look for a bucket where
+ * the last write to it was sequential with the current write, and failing that
+ * we look for a bucket that was last used by the same task.
+ *
+ * The ideas is if you've got multiple tasks pulling data into the cache at the
+ * same time, you'll get better cache utilization if you try to segregate their
+ * data and preserve locality.
+ *
+ * For example, say you've starting Firefox at the same time you're copying a
+ * bunch of files. Firefox will likely end up being fairly hot and stay in the
+ * cache awhile, but the data you copied might not be; if you wrote all that
+ * data to the same buckets it'd get invalidated at the same time.
+ *
+ * Both of those tasks will be doing fairly random IO so we can't rely on
+ * detecting sequential IO to segregate their data, but going off of the task
+ * should be a sane heuristic.
+ */
+static struct open_bucket *pick_data_bucket(struct cache_set *c,
+ const struct bkey *search,
+ struct task_struct *task,
+ struct bkey *alloc)
+{
+ struct open_bucket *ret, *ret_task = NULL;
+
+ list_for_each_entry_reverse(ret, &c->data_buckets, list)
+ if (!bkey_cmp(&ret->key, search))
+ goto found;
+ else if (ret->last == task)
+ ret_task = ret;
+
+ ret = ret_task ?: list_first_entry(&c->data_buckets,
+ struct open_bucket, list);
+found:
+ if (!ret->sectors_free && KEY_PTRS(alloc)) {
+ ret->sectors_free = c->sb.bucket_size;
+ bkey_copy(&ret->key, alloc);
+ bkey_init(alloc);
+ }
+
+ if (!ret->sectors_free)
+ ret = NULL;
+
+ return ret;
+}
+
+/*
+ * Allocates some space in the cache to write to, and k to point to the newly
+ * allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the
+ * end of the newly allocated space).
+ *
+ * May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many
+ * sectors were actually allocated.
+ *
+ * If s->writeback is true, will not fail.
+ */
+static bool bch_alloc_sectors(struct bkey *k, unsigned sectors,
+ struct search *s)
+{
+ struct cache_set *c = s->op.c;
+ struct open_bucket *b;
+ BKEY_PADDED(key) alloc;
+ struct closure cl, *w = NULL;
+ unsigned i;
+
+ if (s->writeback) {
+ closure_init_stack(&cl);
+ w = &cl;
+ }
+
+ /*
+ * We might have to allocate a new bucket, which we can't do with a
+ * spinlock held. So if we have to allocate, we drop the lock, allocate
+ * and then retry. KEY_PTRS() indicates whether alloc points to
+ * allocated bucket(s).
+ */
+
+ bkey_init(&alloc.key);
+ spin_lock(&c->data_bucket_lock);
+
+ while (!(b = pick_data_bucket(c, k, s->task, &alloc.key))) {
+ unsigned watermark = s->op.write_prio
+ ? WATERMARK_MOVINGGC
+ : WATERMARK_NONE;
+
+ spin_unlock(&c->data_bucket_lock);
+
+ if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, w))
+ return false;
+
+ spin_lock(&c->data_bucket_lock);
+ }
+
+ /*
+ * If we had to allocate, we might race and not need to allocate the
+ * second time we call find_data_bucket(). If we allocated a bucket but
+ * didn't use it, drop the refcount bch_bucket_alloc_set() took:
+ */
+ if (KEY_PTRS(&alloc.key))
+ __bkey_put(c, &alloc.key);
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++)
+ EBUG_ON(ptr_stale(c, &b->key, i));
+
+ /* Set up the pointer to the space we're allocating: */
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++)
+ k->ptr[i] = b->key.ptr[i];
+
+ sectors = min(sectors, b->sectors_free);
+
+ SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors);
+ SET_KEY_SIZE(k, sectors);
+ SET_KEY_PTRS(k, KEY_PTRS(&b->key));
+
+ /*
+ * Move b to the end of the lru, and keep track of what this bucket was
+ * last used for:
+ */
+ list_move_tail(&b->list, &c->data_buckets);
+ bkey_copy_key(&b->key, k);
+ b->last = s->task;
+
+ b->sectors_free -= sectors;
+
+ for (i = 0; i < KEY_PTRS(&b->key); i++) {
+ SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors);
+
+ atomic_long_add(sectors,
+ &PTR_CACHE(c, &b->key, i)->sectors_written);
+ }
+
+ if (b->sectors_free < c->sb.block_size)
+ b->sectors_free = 0;
+
+ /*
+ * k takes refcounts on the buckets it points to until it's inserted
+ * into the btree, but if we're done with this bucket we just transfer
+ * get_data_bucket()'s refcount.
+ */
+ if (b->sectors_free)
+ for (i = 0; i < KEY_PTRS(&b->key); i++)
+ atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin);
+
+ spin_unlock(&c->data_bucket_lock);
+ return true;
+}
+
+static void bch_insert_data_error(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+
+ /*
+ * Our data write just errored, which means we've got a bunch of keys to
+ * insert that point to data that wasn't succesfully written.
+ *
+ * We don't have to insert those keys but we still have to invalidate
+ * that region of the cache - so, if we just strip off all the pointers
+ * from the keys we'll accomplish just that.
+ */
+
+ struct bkey *src = op->keys.bottom, *dst = op->keys.bottom;
+
+ while (src != op->keys.top) {
+ struct bkey *n = bkey_next(src);
+
+ SET_KEY_PTRS(src, 0);
+ bkey_copy(dst, src);
+
+ dst = bkey_next(dst);
+ src = n;
+ }
+
+ op->keys.top = dst;
+
+ bch_journal(cl);
+}
+
+static void bch_insert_data_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+ struct search *s = container_of(op, struct search, op);
+
+ if (error) {
+ /* TODO: We could try to recover from this. */
+ if (s->writeback)
+ s->error = error;
+ else if (s->write)
+ set_closure_fn(cl, bch_insert_data_error, bcache_wq);
+ else
+ set_closure_fn(cl, NULL, NULL);
+ }
+
+ bch_bbio_endio(op->c, bio, error, "writing data to cache");
+}
+
+static void bch_insert_data_loop(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+ struct search *s = container_of(op, struct search, op);
+ struct bio *bio = op->cache_bio, *n;
+
+ if (op->skip)
+ return bio_invalidate(cl);
+
+ if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) {
+ set_gc_sectors(op->c);
+ bch_queue_gc(op->c);
+ }
+
+ do {
+ unsigned i;
+ struct bkey *k;
+ struct bio_set *split = s->d
+ ? s->d->bio_split : op->c->bio_split;
+
+ /* 1 for the device pointer and 1 for the chksum */
+ if (bch_keylist_realloc(&op->keys,
+ 1 + (op->csum ? 1 : 0),
+ op->c))
+ continue_at(cl, bch_journal, bcache_wq);
+
+ k = op->keys.top;
+ bkey_init(k);
+ SET_KEY_INODE(k, op->inode);
+ SET_KEY_OFFSET(k, bio->bi_sector);
+
+ if (!bch_alloc_sectors(k, bio_sectors(bio), s))
+ goto err;
+
+ n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
+ if (!n) {
+ __bkey_put(op->c, k);
+ continue_at(cl, bch_insert_data_loop, bcache_wq);
+ }
+
+ n->bi_end_io = bch_insert_data_endio;
+ n->bi_private = cl;
+
+ if (s->writeback) {
+ SET_KEY_DIRTY(k, true);
+
+ for (i = 0; i < KEY_PTRS(k); i++)
+ SET_GC_MARK(PTR_BUCKET(op->c, k, i),
+ GC_MARK_DIRTY);
+ }
+
+ SET_KEY_CSUM(k, op->csum);
+ if (KEY_CSUM(k))
+ bio_csum(n, k);
+
+ pr_debug("%s", pkey(k));
+ bch_keylist_push(&op->keys);
+
+ trace_bcache_cache_insert(n, n->bi_sector, n->bi_bdev);
+ n->bi_rw |= REQ_WRITE;
+ bch_submit_bbio(n, op->c, k, 0);
+ } while (n != bio);
+
+ op->insert_data_done = true;
+ continue_at(cl, bch_journal, bcache_wq);
+err:
+ /* bch_alloc_sectors() blocks if s->writeback = true */
+ BUG_ON(s->writeback);
+
+ /*
+ * But if it's not a writeback write we'd rather just bail out if
+ * there aren't any buckets ready to write to - it might take awhile and
+ * we might be starving btree writes for gc or something.
+ */
+
+ if (s->write) {
+ /*
+ * Writethrough write: We can't complete the write until we've
+ * updated the index. But we don't want to delay the write while
+ * we wait for buckets to be freed up, so just invalidate the
+ * rest of the write.
+ */
+ op->skip = true;
+ return bio_invalidate(cl);
+ } else {
+ /*
+ * From a cache miss, we can just insert the keys for the data
+ * we have written or bail out if we didn't do anything.
+ */
+ op->insert_data_done = true;
+ bio_put(bio);
+
+ if (!bch_keylist_empty(&op->keys))
+ continue_at(cl, bch_journal, bcache_wq);
+ else
+ closure_return(cl);
+ }
+}
+
+/**
+ * bch_insert_data - stick some data in the cache
+ *
+ * This is the starting point for any data to end up in a cache device; it could
+ * be from a normal write, or a writeback write, or a write to a flash only
+ * volume - it's also used by the moving garbage collector to compact data in
+ * mostly empty buckets.
+ *
+ * It first writes the data to the cache, creating a list of keys to be inserted
+ * (if the data had to be fragmented there will be multiple keys); after the
+ * data is written it calls bch_journal, and after the keys have been added to
+ * the next journal write they're inserted into the btree.
+ *
+ * It inserts the data in op->cache_bio; bi_sector is used for the key offset,
+ * and op->inode is used for the key inode.
+ *
+ * If op->skip is true, instead of inserting the data it invalidates the region
+ * of the cache represented by op->cache_bio and op->inode.
+ */
+void bch_insert_data(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+
+ bch_keylist_init(&op->keys);
+ bio_get(op->cache_bio);
+ bch_insert_data_loop(cl);
+}
+
+void bch_btree_insert_async(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+ struct search *s = container_of(op, struct search, op);
+
+ if (bch_btree_insert(op, op->c)) {
+ s->error = -ENOMEM;
+ op->insert_data_done = true;
+ }
+
+ if (op->insert_data_done) {
+ bch_keylist_free(&op->keys);
+ closure_return(cl);
+ } else
+ continue_at(cl, bch_insert_data_loop, bcache_wq);
+}
+
+/* Common code for the make_request functions */
+
+static void request_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+
+ if (error) {
+ struct search *s = container_of(cl, struct search, cl);
+ s->error = error;
+ /* Only cache read errors are recoverable */
+ s->recoverable = false;
+ }
+
+ bio_put(bio);
+ closure_put(cl);
+}
+
+void bch_cache_read_endio(struct bio *bio, int error)
+{
+ struct bbio *b = container_of(bio, struct bbio, bio);
+ struct closure *cl = bio->bi_private;
+ struct search *s = container_of(cl, struct search, cl);
+
+ /*
+ * If the bucket was reused while our bio was in flight, we might have
+ * read the wrong data. Set s->error but not error so it doesn't get
+ * counted against the cache device, but we'll still reread the data
+ * from the backing device.
+ */
+
+ if (error)
+ s->error = error;
+ else if (ptr_stale(s->op.c, &b->key, 0)) {
+ atomic_long_inc(&s->op.c->cache_read_races);
+ s->error = -EINTR;
+ }
+
+ bch_bbio_endio(s->op.c, bio, error, "reading from cache");
+}
+
+static void bio_complete(struct search *s)
+{
+ if (s->orig_bio) {
+ int cpu, rw = bio_data_dir(s->orig_bio);
+ unsigned long duration = jiffies - s->start_time;
+
+ cpu = part_stat_lock();
+ part_round_stats(cpu, &s->d->disk->part0);
+ part_stat_add(cpu, &s->d->disk->part0, ticks[rw], duration);
+ part_stat_unlock();
+
+ trace_bcache_request_end(s, s->orig_bio);
+ bio_endio(s->orig_bio, s->error);
+ s->orig_bio = NULL;
+ }
+}
+
+static void do_bio_hook(struct search *s)
+{
+ struct bio *bio = &s->bio.bio;
+ memcpy(bio, s->orig_bio, sizeof(struct bio));
+
+ bio->bi_end_io = request_endio;
+ bio->bi_private = &s->cl;
+ atomic_set(&bio->bi_cnt, 3);
+}
+
+static void search_free(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ bio_complete(s);
+
+ if (s->op.cache_bio)
+ bio_put(s->op.cache_bio);
+
+ if (s->unaligned_bvec)
+ mempool_free(s->bio.bio.bi_io_vec, s->d->unaligned_bvec);
+
+ closure_debug_destroy(cl);
+ mempool_free(s, s->d->c->search);
+}
+
+static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
+{
+ struct bio_vec *bv;
+ struct search *s = mempool_alloc(d->c->search, GFP_NOIO);
+ memset(s, 0, offsetof(struct search, op.keys));
+
+ __closure_init(&s->cl, NULL);
+
+ s->op.inode = d->id;
+ s->op.c = d->c;
+ s->d = d;
+ s->op.lock = -1;
+ s->task = current;
+ s->orig_bio = bio;
+ s->write = (bio->bi_rw & REQ_WRITE) != 0;
+ s->op.flush_journal = (bio->bi_rw & REQ_FLUSH) != 0;
+ s->op.skip = (bio->bi_rw & REQ_DISCARD) != 0;
+ s->recoverable = 1;
+ s->start_time = jiffies;
+ do_bio_hook(s);
+
+ if (bio->bi_size != bio_segments(bio) * PAGE_SIZE) {
+ bv = mempool_alloc(d->unaligned_bvec, GFP_NOIO);
+ memcpy(bv, bio_iovec(bio),
+ sizeof(struct bio_vec) * bio_segments(bio));
+
+ s->bio.bio.bi_io_vec = bv;
+ s->unaligned_bvec = 1;
+ }
+
+ return s;
+}
+
+static void btree_read_async(struct closure *cl)
+{
+ struct btree_op *op = container_of(cl, struct btree_op, cl);
+
+ int ret = btree_root(search_recurse, op->c, op);
+
+ if (ret == -EAGAIN)
+ continue_at(cl, btree_read_async, bcache_wq);
+
+ closure_return(cl);
+}
+
+/* Cached devices */
+
+static void cached_dev_bio_complete(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+
+ search_free(cl);
+ cached_dev_put(dc);
+}
+
+/* Process reads */
+
+static void cached_dev_read_complete(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+
+ if (s->op.insert_collision)
+ bch_mark_cache_miss_collision(s);
+
+ if (s->op.cache_bio) {
+ int i;
+ struct bio_vec *bv;
+
+ __bio_for_each_segment(bv, s->op.cache_bio, i, 0)
+ __free_page(bv->bv_page);
+ }
+
+ cached_dev_bio_complete(cl);
+}
+
+static void request_read_error(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct bio_vec *bv;
+ int i;
+
+ if (s->recoverable) {
+ /* The cache read failed, but we can retry from the backing
+ * device.
+ */
+ pr_debug("recovering at sector %llu",
+ (uint64_t) s->orig_bio->bi_sector);
+
+ s->error = 0;
+ bv = s->bio.bio.bi_io_vec;
+ do_bio_hook(s);
+ s->bio.bio.bi_io_vec = bv;
+
+ if (!s->unaligned_bvec)
+ bio_for_each_segment(bv, s->orig_bio, i)
+ bv->bv_offset = 0, bv->bv_len = PAGE_SIZE;
+ else
+ memcpy(s->bio.bio.bi_io_vec,
+ bio_iovec(s->orig_bio),
+ sizeof(struct bio_vec) *
+ bio_segments(s->orig_bio));
+
+ /* XXX: invalidate cache */
+
+ trace_bcache_read_retry(&s->bio.bio);
+ closure_bio_submit(&s->bio.bio, &s->cl, s->d);
+ }
+
+ continue_at(cl, cached_dev_read_complete, NULL);
+}
+
+static void request_read_done(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+
+ /*
+ * s->cache_bio != NULL implies that we had a cache miss; cache_bio now
+ * contains data ready to be inserted into the cache.
+ *
+ * First, we copy the data we just read from cache_bio's bounce buffers
+ * to the buffers the original bio pointed to:
+ */
+
+ if (s->op.cache_bio) {
+ struct bio_vec *src, *dst;
+ unsigned src_offset, dst_offset, bytes;
+ void *dst_ptr;
+
+ bio_reset(s->op.cache_bio);
+ s->op.cache_bio->bi_sector = s->cache_miss->bi_sector;
+ s->op.cache_bio->bi_bdev = s->cache_miss->bi_bdev;
+ s->op.cache_bio->bi_size = s->cache_bio_sectors << 9;
+ bio_map(s->op.cache_bio, NULL);
+
+ src = bio_iovec(s->op.cache_bio);
+ dst = bio_iovec(s->cache_miss);
+ src_offset = src->bv_offset;
+ dst_offset = dst->bv_offset;
+ dst_ptr = kmap(dst->bv_page);
+
+ while (1) {
+ if (dst_offset == dst->bv_offset + dst->bv_len) {
+ kunmap(dst->bv_page);
+ dst++;
+ if (dst == bio_iovec_idx(s->cache_miss,
+ s->cache_miss->bi_vcnt))
+ break;
+
+ dst_offset = dst->bv_offset;
+ dst_ptr = kmap(dst->bv_page);
+ }
+
+ if (src_offset == src->bv_offset + src->bv_len) {
+ src++;
+ if (src == bio_iovec_idx(s->op.cache_bio,
+ s->op.cache_bio->bi_vcnt))
+ BUG();
+
+ src_offset = src->bv_offset;
+ }
+
+ bytes = min(dst->bv_offset + dst->bv_len - dst_offset,
+ src->bv_offset + src->bv_len - src_offset);
+
+ memcpy(dst_ptr + dst_offset,
+ page_address(src->bv_page) + src_offset,
+ bytes);
+
+ src_offset += bytes;
+ dst_offset += bytes;
+ }
+
+ bio_put(s->cache_miss);
+ s->cache_miss = NULL;
+ }
+
+ if (verify(dc, &s->bio.bio) && s->recoverable)
+ bch_data_verify(s);
+
+ bio_complete(s);
+
+ if (s->op.cache_bio &&
+ !test_bit(CACHE_SET_STOPPING, &s->op.c->flags)) {
+ s->op.type = BTREE_REPLACE;
+ closure_call(&s->op.cl, bch_insert_data, NULL, cl);
+ }
+
+ continue_at(cl, cached_dev_read_complete, NULL);
+}
+
+static void request_read_done_bh(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+
+ bch_mark_cache_accounting(s, !s->cache_miss, s->op.skip);
+
+ if (s->error)
+ continue_at_nobarrier(cl, request_read_error, bcache_wq);
+ else if (s->op.cache_bio || verify(dc, &s->bio.bio))
+ continue_at_nobarrier(cl, request_read_done, bcache_wq);
+ else
+ continue_at_nobarrier(cl, cached_dev_read_complete, NULL);
+}
+
+static int cached_dev_cache_miss(struct btree *b, struct search *s,
+ struct bio *bio, unsigned sectors)
+{
+ int ret = 0;
+ unsigned reada;
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+ struct bio *miss;
+
+ miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
+ if (!miss)
+ return -EAGAIN;
+
+ if (miss == bio)
+ s->op.lookup_done = true;
+
+ miss->bi_end_io = request_endio;
+ miss->bi_private = &s->cl;
+
+ if (s->cache_miss || s->op.skip)
+ goto out_submit;
+
+ if (miss != bio ||
+ (bio->bi_rw & REQ_RAHEAD) ||
+ (bio->bi_rw & REQ_META) ||
+ s->op.c->gc_stats.in_use >= CUTOFF_CACHE_READA)
+ reada = 0;
+ else {
+ reada = min(dc->readahead >> 9,
+ sectors - bio_sectors(miss));
+
+ if (bio_end(miss) + reada > bdev_sectors(miss->bi_bdev))
+ reada = bdev_sectors(miss->bi_bdev) - bio_end(miss);
+ }
+
+ s->cache_bio_sectors = bio_sectors(miss) + reada;
+ s->op.cache_bio = bio_alloc_bioset(GFP_NOWAIT,
+ DIV_ROUND_UP(s->cache_bio_sectors, PAGE_SECTORS),
+ dc->disk.bio_split);
+
+ if (!s->op.cache_bio)
+ goto out_submit;
+
+ s->op.cache_bio->bi_sector = miss->bi_sector;
+ s->op.cache_bio->bi_bdev = miss->bi_bdev;
+ s->op.cache_bio->bi_size = s->cache_bio_sectors << 9;
+
+ s->op.cache_bio->bi_end_io = request_endio;
+ s->op.cache_bio->bi_private = &s->cl;
+
+ /* btree_search_recurse()'s btree iterator is no good anymore */
+ ret = -EINTR;
+ if (!bch_btree_insert_check_key(b, &s->op, s->op.cache_bio))
+ goto out_put;
+
+ bio_map(s->op.cache_bio, NULL);
+ if (bio_alloc_pages(s->op.cache_bio, __GFP_NOWARN|GFP_NOIO))
+ goto out_put;
+
+ s->cache_miss = miss;
+ bio_get(s->op.cache_bio);
+
+ trace_bcache_cache_miss(s->orig_bio);
+ closure_bio_submit(s->op.cache_bio, &s->cl, s->d);
+
+ return ret;
+out_put:
+ bio_put(s->op.cache_bio);
+ s->op.cache_bio = NULL;
+out_submit:
+ closure_bio_submit(miss, &s->cl, s->d);
+ return ret;
+}
+
+static void request_read(struct cached_dev *dc, struct search *s)
+{
+ struct closure *cl = &s->cl;
+
+ check_should_skip(dc, s);
+ closure_call(&s->op.cl, btree_read_async, NULL, cl);
+
+ continue_at(cl, request_read_done_bh, NULL);
+}
+
+/* Process writes */
+
+static void cached_dev_write_complete(struct closure *cl)
+{
+ struct search *s = container_of(cl, struct search, cl);
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+
+ up_read_non_owner(&dc->writeback_lock);
+ cached_dev_bio_complete(cl);
+}
+
+static bool should_writeback(struct cached_dev *dc, struct bio *bio)
+{
+ unsigned threshold = (bio->bi_rw & REQ_SYNC)
+ ? CUTOFF_WRITEBACK_SYNC
+ : CUTOFF_WRITEBACK;
+
+ return !atomic_read(&dc->disk.detaching) &&
+ cache_mode(dc, bio) == CACHE_MODE_WRITEBACK &&
+ dc->disk.c->gc_stats.in_use < threshold;
+}
+
+static void request_write(struct cached_dev *dc, struct search *s)
+{
+ struct closure *cl = &s->cl;
+ struct bio *bio = &s->bio.bio;
+ struct bkey start, end;
+ start = KEY(dc->disk.id, bio->bi_sector, 0);
+ end = KEY(dc->disk.id, bio_end(bio), 0);
+
+ bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys, &start, &end);
+
+ check_should_skip(dc, s);
+ down_read_non_owner(&dc->writeback_lock);
+
+ if (bch_keybuf_check_overlapping(&dc->writeback_keys, &start, &end)) {
+ s->op.skip = false;
+ s->writeback = true;
+ }
+
+ if (bio->bi_rw & REQ_DISCARD)
+ goto skip;
+
+ if (s->op.skip)
+ goto skip;
+
+ if (should_writeback(dc, s->orig_bio))
+ s->writeback = true;
+
+ if (!s->writeback) {
+ s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO,
+ dc->disk.bio_split);
+
+ trace_bcache_writethrough(s->orig_bio);
+ closure_bio_submit(bio, cl, s->d);
+ } else {
+ s->op.cache_bio = bio;
+ trace_bcache_writeback(s->orig_bio);
+ bch_writeback_add(dc, bio_sectors(bio));
+ }
+out:
+ closure_call(&s->op.cl, bch_insert_data, NULL, cl);
+ continue_at(cl, cached_dev_write_complete, NULL);
+skip:
+ s->op.skip = true;
+ s->op.cache_bio = s->orig_bio;
+ bio_get(s->op.cache_bio);
+ trace_bcache_write_skip(s->orig_bio);
+
+ if ((bio->bi_rw & REQ_DISCARD) &&
+ !blk_queue_discard(bdev_get_queue(dc->bdev)))
+ goto out;
+
+ closure_bio_submit(bio, cl, s->d);
+ goto out;
+}
+
+static void request_nodata(struct cached_dev *dc, struct search *s)
+{
+ struct closure *cl = &s->cl;
+ struct bio *bio = &s->bio.bio;
+
+ if (bio->bi_rw & REQ_DISCARD) {
+ request_write(dc, s);
+ return;
+ }
+
+ if (s->op.flush_journal)
+ bch_journal_meta(s->op.c, cl);
+
+ closure_bio_submit(bio, cl, s->d);
+
+ continue_at(cl, cached_dev_bio_complete, NULL);
+}
+
+/* Cached devices - read & write stuff */
+
+int bch_get_congested(struct cache_set *c)
+{
+ int i;
+
+ if (!c->congested_read_threshold_us &&
+ !c->congested_write_threshold_us)
+ return 0;
+
+ i = (local_clock_us() - c->congested_last_us) / 1024;
+ if (i < 0)
+ return 0;
+
+ i += atomic_read(&c->congested);
+ if (i >= 0)
+ return 0;
+
+ i += CONGESTED_MAX;
+
+ return i <= 0 ? 1 : fract_exp_two(i, 6);
+}
+
+static void add_sequential(struct task_struct *t)
+{
+ ewma_add(t->sequential_io_avg,
+ t->sequential_io, 8, 0);
+
+ t->sequential_io = 0;
+}
+
+static void check_should_skip(struct cached_dev *dc, struct search *s)
+{
+ struct hlist_head *iohash(uint64_t k)
+ { return &dc->io_hash[hash_64(k, RECENT_IO_BITS)]; }
+
+ struct cache_set *c = s->op.c;
+ struct bio *bio = &s->bio.bio;
+
+ long rand;
+ int cutoff = bch_get_congested(c);
+ unsigned mode = cache_mode(dc, bio);
+
+ if (atomic_read(&dc->disk.detaching) ||
+ c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
+ (bio->bi_rw & REQ_DISCARD))
+ goto skip;
+
+ if (mode == CACHE_MODE_NONE ||
+ (mode == CACHE_MODE_WRITEAROUND &&
+ (bio->bi_rw & REQ_WRITE)))
+ goto skip;
+
+ if (bio->bi_sector & (c->sb.block_size - 1) ||
+ bio_sectors(bio) & (c->sb.block_size - 1)) {
+ pr_debug("skipping unaligned io");
+ goto skip;
+ }
+
+ if (!cutoff) {
+ cutoff = dc->sequential_cutoff >> 9;
+
+ if (!cutoff)
+ goto rescale;
+
+ if (mode == CACHE_MODE_WRITEBACK &&
+ (bio->bi_rw & REQ_WRITE) &&
+ (bio->bi_rw & REQ_SYNC))
+ goto rescale;
+ }
+
+ if (dc->sequential_merge) {
+ struct io *i;
+
+ spin_lock(&dc->io_lock);
+
+ hlist_for_each_entry(i, iohash(bio->bi_sector), hash)
+ if (i->last == bio->bi_sector &&
+ time_before(jiffies, i->jiffies))
+ goto found;
+
+ i = list_first_entry(&dc->io_lru, struct io, lru);
+
+ add_sequential(s->task);
+ i->sequential = 0;
+found:
+ if (i->sequential + bio->bi_size > i->sequential)
+ i->sequential += bio->bi_size;
+
+ i->last = bio_end(bio);
+ i->jiffies = jiffies + msecs_to_jiffies(5000);
+ s->task->sequential_io = i->sequential;
+
+ hlist_del(&i->hash);
+ hlist_add_head(&i->hash, iohash(i->last));
+ list_move_tail(&i->lru, &dc->io_lru);
+
+ spin_unlock(&dc->io_lock);
+ } else {
+ s->task->sequential_io = bio->bi_size;
+
+ add_sequential(s->task);
+ }
+
+ rand = get_random_int();
+ cutoff -= bitmap_weight(&rand, BITS_PER_LONG);
+
+ if (cutoff <= (int) (max(s->task->sequential_io,
+ s->task->sequential_io_avg) >> 9))
+ goto skip;
+
+rescale:
+ bch_rescale_priorities(c, bio_sectors(bio));
+ return;
+skip:
+ bch_mark_sectors_bypassed(s, bio_sectors(bio));
+ s->op.skip = true;
+}
+
+static void cached_dev_make_request(struct request_queue *q, struct bio *bio)
+{
+ struct search *s;
+ struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
+ struct cached_dev *dc = container_of(d, struct cached_dev, disk);
+ int cpu, rw = bio_data_dir(bio);
+
+ cpu = part_stat_lock();
+ part_stat_inc(cpu, &d->disk->part0, ios[rw]);
+ part_stat_add(cpu, &d->disk->part0, sectors[rw], bio_sectors(bio));
+ part_stat_unlock();
+
+ bio->bi_bdev = dc->bdev;
+ bio->bi_sector += BDEV_DATA_START;
+
+ if (cached_dev_get(dc)) {
+ s = search_alloc(bio, d);
+ trace_bcache_request_start(s, bio);
+
+ if (!bio_has_data(bio))
+ request_nodata(dc, s);
+ else if (rw)
+ request_write(dc, s);
+ else
+ request_read(dc, s);
+ } else {
+ if ((bio->bi_rw & REQ_DISCARD) &&
+ !blk_queue_discard(bdev_get_queue(dc->bdev)))
+ bio_endio(bio, 0);
+ else
+ bch_generic_make_request(bio, &d->bio_split_hook);
+ }
+}
+
+static int cached_dev_ioctl(struct bcache_device *d, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct cached_dev *dc = container_of(d, struct cached_dev, disk);
+ return __blkdev_driver_ioctl(dc->bdev, mode, cmd, arg);
+}
+
+static int cached_dev_congested(void *data, int bits)
+{
+ struct bcache_device *d = data;
+ struct cached_dev *dc = container_of(d, struct cached_dev, disk);
+ struct request_queue *q = bdev_get_queue(dc->bdev);
+ int ret = 0;
+
+ if (bdi_congested(&q->backing_dev_info, bits))
+ return 1;
+
+ if (cached_dev_get(dc)) {
+ unsigned i;
+ struct cache *ca;
+
+ for_each_cache(ca, d->c, i) {
+ q = bdev_get_queue(ca->bdev);
+ ret |= bdi_congested(&q->backing_dev_info, bits);
+ }
+
+ cached_dev_put(dc);
+ }
+
+ return ret;
+}
+
+void bch_cached_dev_request_init(struct cached_dev *dc)
+{
+ struct gendisk *g = dc->disk.disk;
+
+ g->queue->make_request_fn = cached_dev_make_request;
+ g->queue->backing_dev_info.congested_fn = cached_dev_congested;
+ dc->disk.cache_miss = cached_dev_cache_miss;
+ dc->disk.ioctl = cached_dev_ioctl;
+}
+
+/* Flash backed devices */
+
+static int flash_dev_cache_miss(struct btree *b, struct search *s,
+ struct bio *bio, unsigned sectors)
+{
+ /* Zero fill bio */
+
+ while (bio->bi_idx != bio->bi_vcnt) {
+ struct bio_vec *bv = bio_iovec(bio);
+ unsigned j = min(bv->bv_len >> 9, sectors);
+
+ void *p = kmap(bv->bv_page);
+ memset(p + bv->bv_offset, 0, j << 9);
+ kunmap(bv->bv_page);
+
+ bv->bv_len -= j << 9;
+ bv->bv_offset += j << 9;
+
+ if (bv->bv_len)
+ return 0;
+
+ bio->bi_sector += j;
+ bio->bi_size -= j << 9;
+
+ bio->bi_idx++;
+ sectors -= j;
+ }
+
+ s->op.lookup_done = true;
+
+ return 0;
+}
+
+static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
+{
+ struct search *s;
+ struct closure *cl;
+ struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
+ int cpu, rw = bio_data_dir(bio);
+
+ cpu = part_stat_lock();
+ part_stat_inc(cpu, &d->disk->part0, ios[rw]);
+ part_stat_add(cpu, &d->disk->part0, sectors[rw], bio_sectors(bio));
+ part_stat_unlock();
+
+ s = search_alloc(bio, d);
+ cl = &s->cl;
+ bio = &s->bio.bio;
+
+ trace_bcache_request_start(s, bio);
+
+ if (bio_has_data(bio) && !rw) {
+ closure_call(&s->op.cl, btree_read_async, NULL, cl);
+ } else if (bio_has_data(bio) || s->op.skip) {
+ bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys,
+ &KEY(d->id, bio->bi_sector, 0),
+ &KEY(d->id, bio_end(bio), 0));
+
+ s->writeback = true;
+ s->op.cache_bio = bio;
+
+ closure_call(&s->op.cl, bch_insert_data, NULL, cl);
+ } else {
+ /* No data - probably a cache flush */
+ if (s->op.flush_journal)
+ bch_journal_meta(s->op.c, cl);
+ }
+
+ continue_at(cl, search_free, NULL);
+}
+
+static int flash_dev_ioctl(struct bcache_device *d, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ return -ENOTTY;
+}
+
+static int flash_dev_congested(void *data, int bits)
+{
+ struct bcache_device *d = data;
+ struct request_queue *q;
+ struct cache *ca;
+ unsigned i;
+ int ret = 0;
+
+ for_each_cache(ca, d->c, i) {
+ q = bdev_get_queue(ca->bdev);
+ ret |= bdi_congested(&q->backing_dev_info, bits);
+ }
+
+ return ret;
+}
+
+void bch_flash_dev_request_init(struct bcache_device *d)
+{
+ struct gendisk *g = d->disk;
+
+ g->queue->make_request_fn = flash_dev_make_request;
+ g->queue->backing_dev_info.congested_fn = flash_dev_congested;
+ d->cache_miss = flash_dev_cache_miss;
+ d->ioctl = flash_dev_ioctl;
+}
+
+void bch_request_exit(void)
+{
+#ifdef CONFIG_CGROUP_BCACHE
+ cgroup_unload_subsys(&bcache_subsys);
+#endif
+ if (bch_search_cache)
+ kmem_cache_destroy(bch_search_cache);
+}
+
+int __init bch_request_init(void)
+{
+ bch_search_cache = KMEM_CACHE(search, 0);
+ if (!bch_search_cache)
+ return -ENOMEM;
+
+#ifdef CONFIG_CGROUP_BCACHE
+ cgroup_load_subsys(&bcache_subsys);
+ init_bch_cgroup(&bcache_default_cgroup);
+
+ cgroup_add_cftypes(&bcache_subsys, bch_files);
+#endif
+ return 0;
+}
--- /dev/null
+#ifndef _BCACHE_REQUEST_H_
+#define _BCACHE_REQUEST_H_
+
+#include <linux/cgroup.h>
+
+struct search {
+ /* Stack frame for bio_complete */
+ struct closure cl;
+
+ struct bcache_device *d;
+ struct task_struct *task;
+
+ struct bbio bio;
+ struct bio *orig_bio;
+ struct bio *cache_miss;
+ unsigned cache_bio_sectors;
+
+ unsigned recoverable:1;
+ unsigned unaligned_bvec:1;
+
+ unsigned write:1;
+ unsigned writeback:1;
+
+ /* IO error returned to s->bio */
+ short error;
+ unsigned long start_time;
+
+ /* Anything past op->keys won't get zeroed in do_bio_hook */
+ struct btree_op op;
+};
+
+void bch_cache_read_endio(struct bio *, int);
+int bch_get_congested(struct cache_set *);
+void bch_insert_data(struct closure *cl);
+void bch_btree_insert_async(struct closure *);
+void bch_cache_read_endio(struct bio *, int);
+
+void bch_open_buckets_free(struct cache_set *);
+int bch_open_buckets_alloc(struct cache_set *);
+
+void bch_cached_dev_request_init(struct cached_dev *dc);
+void bch_flash_dev_request_init(struct bcache_device *d);
+
+extern struct kmem_cache *bch_search_cache, *bch_passthrough_cache;
+
+struct bch_cgroup {
+#ifdef CONFIG_CGROUP_BCACHE
+ struct cgroup_subsys_state css;
+#endif
+ /*
+ * We subtract one from the index into bch_cache_modes[], so that
+ * default == -1; this makes it so the rest match up with d->cache_mode,
+ * and we use d->cache_mode if cgrp->cache_mode < 0
+ */
+ short cache_mode;
+ bool verify;
+ struct cache_stat_collector stats;
+};
+
+struct bch_cgroup *bch_bio_to_cgroup(struct bio *bio);
+
+#endif /* _BCACHE_REQUEST_H_ */
--- /dev/null
+/*
+ * bcache stats code
+ *
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "stats.h"
+#include "btree.h"
+#include "request.h"
+#include "sysfs.h"
+
+/*
+ * We keep absolute totals of various statistics, and addionally a set of three
+ * rolling averages.
+ *
+ * Every so often, a timer goes off and rescales the rolling averages.
+ * accounting_rescale[] is how many times the timer has to go off before we
+ * rescale each set of numbers; that gets us half lives of 5 minutes, one hour,
+ * and one day.
+ *
+ * accounting_delay is how often the timer goes off - 22 times in 5 minutes,
+ * and accounting_weight is what we use to rescale:
+ *
+ * pow(31 / 32, 22) ~= 1/2
+ *
+ * So that we don't have to increment each set of numbers every time we (say)
+ * get a cache hit, we increment a single atomic_t in acc->collector, and when
+ * the rescale function runs it resets the atomic counter to 0 and adds its
+ * old value to each of the exported numbers.
+ *
+ * To reduce rounding error, the numbers in struct cache_stats are all
+ * stored left shifted by 16, and scaled back in the sysfs show() function.
+ */
+
+static const unsigned DAY_RESCALE = 288;
+static const unsigned HOUR_RESCALE = 12;
+static const unsigned FIVE_MINUTE_RESCALE = 1;
+static const unsigned accounting_delay = (HZ * 300) / 22;
+static const unsigned accounting_weight = 32;
+
+/* sysfs reading/writing */
+
+read_attribute(cache_hits);
+read_attribute(cache_misses);
+read_attribute(cache_bypass_hits);
+read_attribute(cache_bypass_misses);
+read_attribute(cache_hit_ratio);
+read_attribute(cache_readaheads);
+read_attribute(cache_miss_collisions);
+read_attribute(bypassed);
+
+SHOW(bch_stats)
+{
+ struct cache_stats *s =
+ container_of(kobj, struct cache_stats, kobj);
+#define var(stat) (s->stat >> 16)
+ var_print(cache_hits);
+ var_print(cache_misses);
+ var_print(cache_bypass_hits);
+ var_print(cache_bypass_misses);
+
+ sysfs_print(cache_hit_ratio,
+ DIV_SAFE(var(cache_hits) * 100,
+ var(cache_hits) + var(cache_misses)));
+
+ var_print(cache_readaheads);
+ var_print(cache_miss_collisions);
+ sysfs_hprint(bypassed, var(sectors_bypassed) << 9);
+#undef var
+ return 0;
+}
+
+STORE(bch_stats)
+{
+ return size;
+}
+
+static void bch_stats_release(struct kobject *k)
+{
+}
+
+static struct attribute *bch_stats_files[] = {
+ &sysfs_cache_hits,
+ &sysfs_cache_misses,
+ &sysfs_cache_bypass_hits,
+ &sysfs_cache_bypass_misses,
+ &sysfs_cache_hit_ratio,
+ &sysfs_cache_readaheads,
+ &sysfs_cache_miss_collisions,
+ &sysfs_bypassed,
+ NULL
+};
+static KTYPE(bch_stats);
+
+static void scale_accounting(unsigned long data);
+
+void bch_cache_accounting_init(struct cache_accounting *acc, struct closure *parent)
+{
+ kobject_init(&acc->total.kobj, &bch_stats_ktype);
+ kobject_init(&acc->five_minute.kobj, &bch_stats_ktype);
+ kobject_init(&acc->hour.kobj, &bch_stats_ktype);
+ kobject_init(&acc->day.kobj, &bch_stats_ktype);
+
+ closure_init(&acc->cl, parent);
+ init_timer(&acc->timer);
+ acc->timer.expires = jiffies + accounting_delay;
+ acc->timer.data = (unsigned long) acc;
+ acc->timer.function = scale_accounting;
+ add_timer(&acc->timer);
+}
+
+int bch_cache_accounting_add_kobjs(struct cache_accounting *acc,
+ struct kobject *parent)
+{
+ int ret = kobject_add(&acc->total.kobj, parent,
+ "stats_total");
+ ret = ret ?: kobject_add(&acc->five_minute.kobj, parent,
+ "stats_five_minute");
+ ret = ret ?: kobject_add(&acc->hour.kobj, parent,
+ "stats_hour");
+ ret = ret ?: kobject_add(&acc->day.kobj, parent,
+ "stats_day");
+ return ret;
+}
+
+void bch_cache_accounting_clear(struct cache_accounting *acc)
+{
+ memset(&acc->total.cache_hits,
+ 0,
+ sizeof(unsigned long) * 7);
+}
+
+void bch_cache_accounting_destroy(struct cache_accounting *acc)
+{
+ kobject_put(&acc->total.kobj);
+ kobject_put(&acc->five_minute.kobj);
+ kobject_put(&acc->hour.kobj);
+ kobject_put(&acc->day.kobj);
+
+ atomic_set(&acc->closing, 1);
+ if (del_timer_sync(&acc->timer))
+ closure_return(&acc->cl);
+}
+
+/* EWMA scaling */
+
+static void scale_stat(unsigned long *stat)
+{
+ *stat = ewma_add(*stat, 0, accounting_weight, 0);
+}
+
+static void scale_stats(struct cache_stats *stats, unsigned long rescale_at)
+{
+ if (++stats->rescale == rescale_at) {
+ stats->rescale = 0;
+ scale_stat(&stats->cache_hits);
+ scale_stat(&stats->cache_misses);
+ scale_stat(&stats->cache_bypass_hits);
+ scale_stat(&stats->cache_bypass_misses);
+ scale_stat(&stats->cache_readaheads);
+ scale_stat(&stats->cache_miss_collisions);
+ scale_stat(&stats->sectors_bypassed);
+ }
+}
+
+static void scale_accounting(unsigned long data)
+{
+ struct cache_accounting *acc = (struct cache_accounting *) data;
+
+#define move_stat(name) do { \
+ unsigned t = atomic_xchg(&acc->collector.name, 0); \
+ t <<= 16; \
+ acc->five_minute.name += t; \
+ acc->hour.name += t; \
+ acc->day.name += t; \
+ acc->total.name += t; \
+} while (0)
+
+ move_stat(cache_hits);
+ move_stat(cache_misses);
+ move_stat(cache_bypass_hits);
+ move_stat(cache_bypass_misses);
+ move_stat(cache_readaheads);
+ move_stat(cache_miss_collisions);
+ move_stat(sectors_bypassed);
+
+ scale_stats(&acc->total, 0);
+ scale_stats(&acc->day, DAY_RESCALE);
+ scale_stats(&acc->hour, HOUR_RESCALE);
+ scale_stats(&acc->five_minute, FIVE_MINUTE_RESCALE);
+
+ acc->timer.expires += accounting_delay;
+
+ if (!atomic_read(&acc->closing))
+ add_timer(&acc->timer);
+ else
+ closure_return(&acc->cl);
+}
+
+static void mark_cache_stats(struct cache_stat_collector *stats,
+ bool hit, bool bypass)
+{
+ if (!bypass)
+ if (hit)
+ atomic_inc(&stats->cache_hits);
+ else
+ atomic_inc(&stats->cache_misses);
+ else
+ if (hit)
+ atomic_inc(&stats->cache_bypass_hits);
+ else
+ atomic_inc(&stats->cache_bypass_misses);
+}
+
+void bch_mark_cache_accounting(struct search *s, bool hit, bool bypass)
+{
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+ mark_cache_stats(&dc->accounting.collector, hit, bypass);
+ mark_cache_stats(&s->op.c->accounting.collector, hit, bypass);
+#ifdef CONFIG_CGROUP_BCACHE
+ mark_cache_stats(&(bch_bio_to_cgroup(s->orig_bio)->stats), hit, bypass);
+#endif
+}
+
+void bch_mark_cache_readahead(struct search *s)
+{
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+ atomic_inc(&dc->accounting.collector.cache_readaheads);
+ atomic_inc(&s->op.c->accounting.collector.cache_readaheads);
+}
+
+void bch_mark_cache_miss_collision(struct search *s)
+{
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+ atomic_inc(&dc->accounting.collector.cache_miss_collisions);
+ atomic_inc(&s->op.c->accounting.collector.cache_miss_collisions);
+}
+
+void bch_mark_sectors_bypassed(struct search *s, int sectors)
+{
+ struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+ atomic_add(sectors, &dc->accounting.collector.sectors_bypassed);
+ atomic_add(sectors, &s->op.c->accounting.collector.sectors_bypassed);
+}
--- /dev/null
+#ifndef _BCACHE_STATS_H_
+#define _BCACHE_STATS_H_
+
+struct cache_stat_collector {
+ atomic_t cache_hits;
+ atomic_t cache_misses;
+ atomic_t cache_bypass_hits;
+ atomic_t cache_bypass_misses;
+ atomic_t cache_readaheads;
+ atomic_t cache_miss_collisions;
+ atomic_t sectors_bypassed;
+};
+
+struct cache_stats {
+ struct kobject kobj;
+
+ unsigned long cache_hits;
+ unsigned long cache_misses;
+ unsigned long cache_bypass_hits;
+ unsigned long cache_bypass_misses;
+ unsigned long cache_readaheads;
+ unsigned long cache_miss_collisions;
+ unsigned long sectors_bypassed;
+
+ unsigned rescale;
+};
+
+struct cache_accounting {
+ struct closure cl;
+ struct timer_list timer;
+ atomic_t closing;
+
+ struct cache_stat_collector collector;
+
+ struct cache_stats total;
+ struct cache_stats five_minute;
+ struct cache_stats hour;
+ struct cache_stats day;
+};
+
+struct search;
+
+void bch_cache_accounting_init(struct cache_accounting *acc,
+ struct closure *parent);
+
+int bch_cache_accounting_add_kobjs(struct cache_accounting *acc,
+ struct kobject *parent);
+
+void bch_cache_accounting_clear(struct cache_accounting *acc);
+
+void bch_cache_accounting_destroy(struct cache_accounting *acc);
+
+void bch_mark_cache_accounting(struct search *s, bool hit, bool bypass);
+void bch_mark_cache_readahead(struct search *s);
+void bch_mark_cache_miss_collision(struct search *s);
+void bch_mark_sectors_bypassed(struct search *s, int sectors);
+
+#endif /* _BCACHE_STATS_H_ */
--- /dev/null
+/*
+ * bcache setup/teardown code, and some metadata io - read a superblock and
+ * figure out what to do with it.
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+#include "request.h"
+
+#include <linux/buffer_head.h>
+#include <linux/debugfs.h>
+#include <linux/genhd.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/reboot.h>
+#include <linux/sysfs.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Kent Overstreet <kent.overstreet@gmail.com>");
+
+static const char bcache_magic[] = {
+ 0xc6, 0x85, 0x73, 0xf6, 0x4e, 0x1a, 0x45, 0xca,
+ 0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81
+};
+
+static const char invalid_uuid[] = {
+ 0xa0, 0x3e, 0xf8, 0xed, 0x3e, 0xe1, 0xb8, 0x78,
+ 0xc8, 0x50, 0xfc, 0x5e, 0xcb, 0x16, 0xcd, 0x99
+};
+
+/* Default is -1; we skip past it for struct cached_dev's cache mode */
+const char * const bch_cache_modes[] = {
+ "default",
+ "writethrough",
+ "writeback",
+ "writearound",
+ "none",
+ NULL
+};
+
+struct uuid_entry_v0 {
+ uint8_t uuid[16];
+ uint8_t label[32];
+ uint32_t first_reg;
+ uint32_t last_reg;
+ uint32_t invalidated;
+ uint32_t pad;
+};
+
+static struct kobject *bcache_kobj;
+struct mutex bch_register_lock;
+LIST_HEAD(bch_cache_sets);
+static LIST_HEAD(uncached_devices);
+
+static int bcache_major, bcache_minor;
+static wait_queue_head_t unregister_wait;
+struct workqueue_struct *bcache_wq;
+
+#define BTREE_MAX_PAGES (256 * 1024 / PAGE_SIZE)
+
+static void bio_split_pool_free(struct bio_split_pool *p)
+{
+ if (p->bio_split)
+ bioset_free(p->bio_split);
+
+}
+
+static int bio_split_pool_init(struct bio_split_pool *p)
+{
+ p->bio_split = bioset_create(4, 0);
+ if (!p->bio_split)
+ return -ENOMEM;
+
+ p->bio_split_hook = mempool_create_kmalloc_pool(4,
+ sizeof(struct bio_split_hook));
+ if (!p->bio_split_hook)
+ return -ENOMEM;
+
+ return 0;
+}
+
+/* Superblock */
+
+static const char *read_super(struct cache_sb *sb, struct block_device *bdev,
+ struct page **res)
+{
+ const char *err;
+ struct cache_sb *s;
+ struct buffer_head *bh = __bread(bdev, 1, SB_SIZE);
+ unsigned i;
+
+ if (!bh)
+ return "IO error";
+
+ s = (struct cache_sb *) bh->b_data;
+
+ sb->offset = le64_to_cpu(s->offset);
+ sb->version = le64_to_cpu(s->version);
+
+ memcpy(sb->magic, s->magic, 16);
+ memcpy(sb->uuid, s->uuid, 16);
+ memcpy(sb->set_uuid, s->set_uuid, 16);
+ memcpy(sb->label, s->label, SB_LABEL_SIZE);
+
+ sb->flags = le64_to_cpu(s->flags);
+ sb->seq = le64_to_cpu(s->seq);
+
+ sb->nbuckets = le64_to_cpu(s->nbuckets);
+ sb->block_size = le16_to_cpu(s->block_size);
+ sb->bucket_size = le16_to_cpu(s->bucket_size);
+
+ sb->nr_in_set = le16_to_cpu(s->nr_in_set);
+ sb->nr_this_dev = le16_to_cpu(s->nr_this_dev);
+ sb->last_mount = le32_to_cpu(s->last_mount);
+
+ sb->first_bucket = le16_to_cpu(s->first_bucket);
+ sb->keys = le16_to_cpu(s->keys);
+
+ for (i = 0; i < SB_JOURNAL_BUCKETS; i++)
+ sb->d[i] = le64_to_cpu(s->d[i]);
+
+ pr_debug("read sb version %llu, flags %llu, seq %llu, journal size %u",
+ sb->version, sb->flags, sb->seq, sb->keys);
+
+ err = "Not a bcache superblock";
+ if (sb->offset != SB_SECTOR)
+ goto err;
+
+ if (memcmp(sb->magic, bcache_magic, 16))
+ goto err;
+
+ err = "Too many journal buckets";
+ if (sb->keys > SB_JOURNAL_BUCKETS)
+ goto err;
+
+ err = "Bad checksum";
+ if (s->csum != csum_set(s))
+ goto err;
+
+ err = "Bad UUID";
+ if (is_zero(sb->uuid, 16))
+ goto err;
+
+ err = "Unsupported superblock version";
+ if (sb->version > BCACHE_SB_VERSION)
+ goto err;
+
+ err = "Bad block/bucket size";
+ if (!is_power_of_2(sb->block_size) || sb->block_size > PAGE_SECTORS ||
+ !is_power_of_2(sb->bucket_size) || sb->bucket_size < PAGE_SECTORS)
+ goto err;
+
+ err = "Too many buckets";
+ if (sb->nbuckets > LONG_MAX)
+ goto err;
+
+ err = "Not enough buckets";
+ if (sb->nbuckets < 1 << 7)
+ goto err;
+
+ err = "Invalid superblock: device too small";
+ if (get_capacity(bdev->bd_disk) < sb->bucket_size * sb->nbuckets)
+ goto err;
+
+ if (sb->version == CACHE_BACKING_DEV)
+ goto out;
+
+ err = "Bad UUID";
+ if (is_zero(sb->set_uuid, 16))
+ goto err;
+
+ err = "Bad cache device number in set";
+ if (!sb->nr_in_set ||
+ sb->nr_in_set <= sb->nr_this_dev ||
+ sb->nr_in_set > MAX_CACHES_PER_SET)
+ goto err;
+
+ err = "Journal buckets not sequential";
+ for (i = 0; i < sb->keys; i++)
+ if (sb->d[i] != sb->first_bucket + i)
+ goto err;
+
+ err = "Too many journal buckets";
+ if (sb->first_bucket + sb->keys > sb->nbuckets)
+ goto err;
+
+ err = "Invalid superblock: first bucket comes before end of super";
+ if (sb->first_bucket * sb->bucket_size < 16)
+ goto err;
+out:
+ sb->last_mount = get_seconds();
+ err = NULL;
+
+ get_page(bh->b_page);
+ *res = bh->b_page;
+err:
+ put_bh(bh);
+ return err;
+}
+
+static void write_bdev_super_endio(struct bio *bio, int error)
+{
+ struct cached_dev *dc = bio->bi_private;
+ /* XXX: error checking */
+
+ closure_put(&dc->sb_write.cl);
+}
+
+static void __write_super(struct cache_sb *sb, struct bio *bio)
+{
+ struct cache_sb *out = page_address(bio->bi_io_vec[0].bv_page);
+ unsigned i;
+
+ bio->bi_sector = SB_SECTOR;
+ bio->bi_rw = REQ_SYNC|REQ_META;
+ bio->bi_size = SB_SIZE;
+ bio_map(bio, NULL);
+
+ out->offset = cpu_to_le64(sb->offset);
+ out->version = cpu_to_le64(sb->version);
+
+ memcpy(out->uuid, sb->uuid, 16);
+ memcpy(out->set_uuid, sb->set_uuid, 16);
+ memcpy(out->label, sb->label, SB_LABEL_SIZE);
+
+ out->flags = cpu_to_le64(sb->flags);
+ out->seq = cpu_to_le64(sb->seq);
+
+ out->last_mount = cpu_to_le32(sb->last_mount);
+ out->first_bucket = cpu_to_le16(sb->first_bucket);
+ out->keys = cpu_to_le16(sb->keys);
+
+ for (i = 0; i < sb->keys; i++)
+ out->d[i] = cpu_to_le64(sb->d[i]);
+
+ out->csum = csum_set(out);
+
+ pr_debug("ver %llu, flags %llu, seq %llu",
+ sb->version, sb->flags, sb->seq);
+
+ submit_bio(REQ_WRITE, bio);
+}
+
+void bch_write_bdev_super(struct cached_dev *dc, struct closure *parent)
+{
+ struct closure *cl = &dc->sb_write.cl;
+ struct bio *bio = &dc->sb_bio;
+
+ closure_lock(&dc->sb_write, parent);
+
+ bio_reset(bio);
+ bio->bi_bdev = dc->bdev;
+ bio->bi_end_io = write_bdev_super_endio;
+ bio->bi_private = dc;
+
+ closure_get(cl);
+ __write_super(&dc->sb, bio);
+
+ closure_return(cl);
+}
+
+static void write_super_endio(struct bio *bio, int error)
+{
+ struct cache *ca = bio->bi_private;
+
+ bch_count_io_errors(ca, error, "writing superblock");
+ closure_put(&ca->set->sb_write.cl);
+}
+
+void bcache_write_super(struct cache_set *c)
+{
+ struct closure *cl = &c->sb_write.cl;
+ struct cache *ca;
+ unsigned i;
+
+ closure_lock(&c->sb_write, &c->cl);
+
+ c->sb.seq++;
+
+ for_each_cache(ca, c, i) {
+ struct bio *bio = &ca->sb_bio;
+
+ ca->sb.version = BCACHE_SB_VERSION;
+ ca->sb.seq = c->sb.seq;
+ ca->sb.last_mount = c->sb.last_mount;
+
+ SET_CACHE_SYNC(&ca->sb, CACHE_SYNC(&c->sb));
+
+ bio_reset(bio);
+ bio->bi_bdev = ca->bdev;
+ bio->bi_end_io = write_super_endio;
+ bio->bi_private = ca;
+
+ closure_get(cl);
+ __write_super(&ca->sb, bio);
+ }
+
+ closure_return(cl);
+}
+
+/* UUID io */
+
+static void uuid_endio(struct bio *bio, int error)
+{
+ struct closure *cl = bio->bi_private;
+ struct cache_set *c = container_of(cl, struct cache_set, uuid_write.cl);
+
+ cache_set_err_on(error, c, "accessing uuids");
+ bch_bbio_free(bio, c);
+ closure_put(cl);
+}
+
+static void uuid_io(struct cache_set *c, unsigned long rw,
+ struct bkey *k, struct closure *parent)
+{
+ struct closure *cl = &c->uuid_write.cl;
+ struct uuid_entry *u;
+ unsigned i;
+
+ BUG_ON(!parent);
+ closure_lock(&c->uuid_write, parent);
+
+ for (i = 0; i < KEY_PTRS(k); i++) {
+ struct bio *bio = bch_bbio_alloc(c);
+
+ bio->bi_rw = REQ_SYNC|REQ_META|rw;
+ bio->bi_size = KEY_SIZE(k) << 9;
+
+ bio->bi_end_io = uuid_endio;
+ bio->bi_private = cl;
+ bio_map(bio, c->uuids);
+
+ bch_submit_bbio(bio, c, k, i);
+
+ if (!(rw & WRITE))
+ break;
+ }
+
+ pr_debug("%s UUIDs at %s", rw & REQ_WRITE ? "wrote" : "read",
+ pkey(&c->uuid_bucket));
+
+ for (u = c->uuids; u < c->uuids + c->nr_uuids; u++)
+ if (!is_zero(u->uuid, 16))
+ pr_debug("Slot %zi: %pU: %s: 1st: %u last: %u inv: %u",
+ u - c->uuids, u->uuid, u->label,
+ u->first_reg, u->last_reg, u->invalidated);
+
+ closure_return(cl);
+}
+
+static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
+{
+ struct bkey *k = &j->uuid_bucket;
+
+ if (__bch_ptr_invalid(c, 1, k))
+ return "bad uuid pointer";
+
+ bkey_copy(&c->uuid_bucket, k);
+ uuid_io(c, READ_SYNC, k, cl);
+
+ if (j->version < BCACHE_JSET_VERSION_UUIDv1) {
+ struct uuid_entry_v0 *u0 = (void *) c->uuids;
+ struct uuid_entry *u1 = (void *) c->uuids;
+ int i;
+
+ closure_sync(cl);
+
+ /*
+ * Since the new uuid entry is bigger than the old, we have to
+ * convert starting at the highest memory address and work down
+ * in order to do it in place
+ */
+
+ for (i = c->nr_uuids - 1;
+ i >= 0;
+ --i) {
+ memcpy(u1[i].uuid, u0[i].uuid, 16);
+ memcpy(u1[i].label, u0[i].label, 32);
+
+ u1[i].first_reg = u0[i].first_reg;
+ u1[i].last_reg = u0[i].last_reg;
+ u1[i].invalidated = u0[i].invalidated;
+
+ u1[i].flags = 0;
+ u1[i].sectors = 0;
+ }
+ }
+
+ return NULL;
+}
+
+static int __uuid_write(struct cache_set *c)
+{
+ BKEY_PADDED(key) k;
+ struct closure cl;
+ closure_init_stack(&cl);
+
+ lockdep_assert_held(&bch_register_lock);
+
+ if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, &cl))
+ return 1;
+
+ SET_KEY_SIZE(&k.key, c->sb.bucket_size);
+ uuid_io(c, REQ_WRITE, &k.key, &cl);
+ closure_sync(&cl);
+
+ bkey_copy(&c->uuid_bucket, &k.key);
+ __bkey_put(c, &k.key);
+ return 0;
+}
+
+int bch_uuid_write(struct cache_set *c)
+{
+ int ret = __uuid_write(c);
+
+ if (!ret)
+ bch_journal_meta(c, NULL);
+
+ return ret;
+}
+
+static struct uuid_entry *uuid_find(struct cache_set *c, const char *uuid)
+{
+ struct uuid_entry *u;
+
+ for (u = c->uuids;
+ u < c->uuids + c->nr_uuids; u++)
+ if (!memcmp(u->uuid, uuid, 16))
+ return u;
+
+ return NULL;
+}
+
+static struct uuid_entry *uuid_find_empty(struct cache_set *c)
+{
+ static const char zero_uuid[16] = "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
+ return uuid_find(c, zero_uuid);
+}
+
+/*
+ * Bucket priorities/gens:
+ *
+ * For each bucket, we store on disk its
+ * 8 bit gen
+ * 16 bit priority
+ *
+ * See alloc.c for an explanation of the gen. The priority is used to implement
+ * lru (and in the future other) cache replacement policies; for most purposes
+ * it's just an opaque integer.
+ *
+ * The gens and the priorities don't have a whole lot to do with each other, and
+ * it's actually the gens that must be written out at specific times - it's no
+ * big deal if the priorities don't get written, if we lose them we just reuse
+ * buckets in suboptimal order.
+ *
+ * On disk they're stored in a packed array, and in as many buckets are required
+ * to fit them all. The buckets we use to store them form a list; the journal
+ * header points to the first bucket, the first bucket points to the second
+ * bucket, et cetera.
+ *
+ * This code is used by the allocation code; periodically (whenever it runs out
+ * of buckets to allocate from) the allocation code will invalidate some
+ * buckets, but it can't use those buckets until their new gens are safely on
+ * disk.
+ */
+
+static void prio_endio(struct bio *bio, int error)
+{
+ struct cache *ca = bio->bi_private;
+
+ cache_set_err_on(error, ca->set, "accessing priorities");
+ bch_bbio_free(bio, ca->set);
+ closure_put(&ca->prio);
+}
+
+static void prio_io(struct cache *ca, uint64_t bucket, unsigned long rw)
+{
+ struct closure *cl = &ca->prio;
+ struct bio *bio = bch_bbio_alloc(ca->set);
+
+ closure_init_stack(cl);
+
+ bio->bi_sector = bucket * ca->sb.bucket_size;
+ bio->bi_bdev = ca->bdev;
+ bio->bi_rw = REQ_SYNC|REQ_META|rw;
+ bio->bi_size = bucket_bytes(ca);
+
+ bio->bi_end_io = prio_endio;
+ bio->bi_private = ca;
+ bio_map(bio, ca->disk_buckets);
+
+ closure_bio_submit(bio, &ca->prio, ca);
+ closure_sync(cl);
+}
+
+#define buckets_free(c) "free %zu, free_inc %zu, unused %zu", \
+ fifo_used(&c->free), fifo_used(&c->free_inc), fifo_used(&c->unused)
+
+void bch_prio_write(struct cache *ca)
+{
+ int i;
+ struct bucket *b;
+ struct closure cl;
+
+ closure_init_stack(&cl);
+
+ lockdep_assert_held(&ca->set->bucket_lock);
+
+ for (b = ca->buckets;
+ b < ca->buckets + ca->sb.nbuckets; b++)
+ b->disk_gen = b->gen;
+
+ ca->disk_buckets->seq++;
+
+ atomic_long_add(ca->sb.bucket_size * prio_buckets(ca),
+ &ca->meta_sectors_written);
+
+ pr_debug("free %zu, free_inc %zu, unused %zu", fifo_used(&ca->free),
+ fifo_used(&ca->free_inc), fifo_used(&ca->unused));
+ blktrace_msg(ca, "Starting priorities: " buckets_free(ca));
+
+ for (i = prio_buckets(ca) - 1; i >= 0; --i) {
+ long bucket;
+ struct prio_set *p = ca->disk_buckets;
+ struct bucket_disk *d = p->data, *end = d + prios_per_bucket(ca);
+
+ for (b = ca->buckets + i * prios_per_bucket(ca);
+ b < ca->buckets + ca->sb.nbuckets && d < end;
+ b++, d++) {
+ d->prio = cpu_to_le16(b->prio);
+ d->gen = b->gen;
+ }
+
+ p->next_bucket = ca->prio_buckets[i + 1];
+ p->magic = pset_magic(ca);
+ p->csum = crc64(&p->magic, bucket_bytes(ca) - 8);
+
+ bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, &cl);
+ BUG_ON(bucket == -1);
+
+ mutex_unlock(&ca->set->bucket_lock);
+ prio_io(ca, bucket, REQ_WRITE);
+ mutex_lock(&ca->set->bucket_lock);
+
+ ca->prio_buckets[i] = bucket;
+ atomic_dec_bug(&ca->buckets[bucket].pin);
+ }
+
+ mutex_unlock(&ca->set->bucket_lock);
+
+ bch_journal_meta(ca->set, &cl);
+ closure_sync(&cl);
+
+ mutex_lock(&ca->set->bucket_lock);
+
+ ca->need_save_prio = 0;
+
+ /*
+ * Don't want the old priorities to get garbage collected until after we
+ * finish writing the new ones, and they're journalled
+ */
+ for (i = 0; i < prio_buckets(ca); i++)
+ ca->prio_last_buckets[i] = ca->prio_buckets[i];
+}
+
+static void prio_read(struct cache *ca, uint64_t bucket)
+{
+ struct prio_set *p = ca->disk_buckets;
+ struct bucket_disk *d = p->data + prios_per_bucket(ca), *end = d;
+ struct bucket *b;
+ unsigned bucket_nr = 0;
+
+ for (b = ca->buckets;
+ b < ca->buckets + ca->sb.nbuckets;
+ b++, d++) {
+ if (d == end) {
+ ca->prio_buckets[bucket_nr] = bucket;
+ ca->prio_last_buckets[bucket_nr] = bucket;
+ bucket_nr++;
+
+ prio_io(ca, bucket, READ_SYNC);
+
+ if (p->csum != crc64(&p->magic, bucket_bytes(ca) - 8))
+ pr_warn("bad csum reading priorities");
+
+ if (p->magic != pset_magic(ca))
+ pr_warn("bad magic reading priorities");
+
+ bucket = p->next_bucket;
+ d = p->data;
+ }
+
+ b->prio = le16_to_cpu(d->prio);
+ b->gen = b->disk_gen = b->last_gc = b->gc_gen = d->gen;
+ }
+}
+
+/* Bcache device */
+
+static int open_dev(struct block_device *b, fmode_t mode)
+{
+ struct bcache_device *d = b->bd_disk->private_data;
+ if (atomic_read(&d->closing))
+ return -ENXIO;
+
+ closure_get(&d->cl);
+ return 0;
+}
+
+static int release_dev(struct gendisk *b, fmode_t mode)
+{
+ struct bcache_device *d = b->private_data;
+ closure_put(&d->cl);
+ return 0;
+}
+
+static int ioctl_dev(struct block_device *b, fmode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct bcache_device *d = b->bd_disk->private_data;
+ return d->ioctl(d, mode, cmd, arg);
+}
+
+static const struct block_device_operations bcache_ops = {
+ .open = open_dev,
+ .release = release_dev,
+ .ioctl = ioctl_dev,
+ .owner = THIS_MODULE,
+};
+
+void bcache_device_stop(struct bcache_device *d)
+{
+ if (!atomic_xchg(&d->closing, 1))
+ closure_queue(&d->cl);
+}
+
+static void bcache_device_detach(struct bcache_device *d)
+{
+ lockdep_assert_held(&bch_register_lock);
+
+ if (atomic_read(&d->detaching)) {
+ struct uuid_entry *u = d->c->uuids + d->id;
+
+ SET_UUID_FLASH_ONLY(u, 0);
+ memcpy(u->uuid, invalid_uuid, 16);
+ u->invalidated = cpu_to_le32(get_seconds());
+ bch_uuid_write(d->c);
+
+ atomic_set(&d->detaching, 0);
+ }
+
+ d->c->devices[d->id] = NULL;
+ closure_put(&d->c->caching);
+ d->c = NULL;
+}
+
+static void bcache_device_attach(struct bcache_device *d, struct cache_set *c,
+ unsigned id)
+{
+ BUG_ON(test_bit(CACHE_SET_STOPPING, &c->flags));
+
+ d->id = id;
+ d->c = c;
+ c->devices[id] = d;
+
+ closure_get(&c->caching);
+}
+
+static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
+ const char *name)
+{
+ snprintf(d->name, BCACHEDEVNAME_SIZE,
+ "%s%u", name, d->id);
+
+ WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
+ sysfs_create_link(&c->kobj, &d->kobj, d->name),
+ "Couldn't create device <-> cache set symlinks");
+}
+
+static void bcache_device_free(struct bcache_device *d)
+{
+ lockdep_assert_held(&bch_register_lock);
+
+ pr_info("%s stopped", d->disk->disk_name);
+
+ if (d->c)
+ bcache_device_detach(d);
+
+ if (d->disk)
+ del_gendisk(d->disk);
+ if (d->disk && d->disk->queue)
+ blk_cleanup_queue(d->disk->queue);
+ if (d->disk)
+ put_disk(d->disk);
+
+ bio_split_pool_free(&d->bio_split_hook);
+ if (d->unaligned_bvec)
+ mempool_destroy(d->unaligned_bvec);
+ if (d->bio_split)
+ bioset_free(d->bio_split);
+
+ closure_debug_destroy(&d->cl);
+}
+
+static int bcache_device_init(struct bcache_device *d, unsigned block_size)
+{
+ struct request_queue *q;
+
+ if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
+ !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
+ sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
+ bio_split_pool_init(&d->bio_split_hook))
+
+ return -ENOMEM;
+
+ d->disk = alloc_disk(1);
+ if (!d->disk)
+ return -ENOMEM;
+
+ snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor);
+
+ d->disk->major = bcache_major;
+ d->disk->first_minor = bcache_minor++;
+ d->disk->fops = &bcache_ops;
+ d->disk->private_data = d;
+
+ q = blk_alloc_queue(GFP_KERNEL);
+ if (!q)
+ return -ENOMEM;
+
+ blk_queue_make_request(q, NULL);
+ d->disk->queue = q;
+ q->queuedata = d;
+ q->backing_dev_info.congested_data = d;
+ q->limits.max_hw_sectors = UINT_MAX;
+ q->limits.max_sectors = UINT_MAX;
+ q->limits.max_segment_size = UINT_MAX;
+ q->limits.max_segments = BIO_MAX_PAGES;
+ q->limits.max_discard_sectors = UINT_MAX;
+ q->limits.io_min = block_size;
+ q->limits.logical_block_size = block_size;
+ q->limits.physical_block_size = block_size;
+ set_bit(QUEUE_FLAG_NONROT, &d->disk->queue->queue_flags);
+ set_bit(QUEUE_FLAG_DISCARD, &d->disk->queue->queue_flags);
+
+ return 0;
+}
+
+/* Cached device */
+
+static void calc_cached_dev_sectors(struct cache_set *c)
+{
+ uint64_t sectors = 0;
+ struct cached_dev *dc;
+
+ list_for_each_entry(dc, &c->cached_devs, list)
+ sectors += bdev_sectors(dc->bdev);
+
+ c->cached_dev_sectors = sectors;
+}
+
+void bch_cached_dev_run(struct cached_dev *dc)
+{
+ struct bcache_device *d = &dc->disk;
+
+ if (atomic_xchg(&dc->running, 1))
+ return;
+
+ if (!d->c &&
+ BDEV_STATE(&dc->sb) != BDEV_STATE_NONE) {
+ struct closure cl;
+ closure_init_stack(&cl);
+
+ SET_BDEV_STATE(&dc->sb, BDEV_STATE_STALE);
+ bch_write_bdev_super(dc, &cl);
+ closure_sync(&cl);
+ }
+
+ add_disk(d->disk);
+#if 0
+ char *env[] = { "SYMLINK=label" , NULL };
+ kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
+#endif
+ if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
+ sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
+ pr_debug("error creating sysfs link");
+}
+
+static void cached_dev_detach_finish(struct work_struct *w)
+{
+ struct cached_dev *dc = container_of(w, struct cached_dev, detach);
+ char buf[BDEVNAME_SIZE];
+ struct closure cl;
+ closure_init_stack(&cl);
+
+ BUG_ON(!atomic_read(&dc->disk.detaching));
+ BUG_ON(atomic_read(&dc->count));
+
+ sysfs_remove_link(&dc->disk.c->kobj, dc->disk.name);
+ sysfs_remove_link(&dc->disk.kobj, "cache");
+
+ mutex_lock(&bch_register_lock);
+
+ memset(&dc->sb.set_uuid, 0, 16);
+ SET_BDEV_STATE(&dc->sb, BDEV_STATE_NONE);
+
+ bch_write_bdev_super(dc, &cl);
+ closure_sync(&cl);
+
+ bcache_device_detach(&dc->disk);
+ list_move(&dc->list, &uncached_devices);
+
+ mutex_unlock(&bch_register_lock);
+
+ pr_info("Caching disabled for %s", bdevname(dc->bdev, buf));
+
+ /* Drop ref we took in cached_dev_detach() */
+ closure_put(&dc->disk.cl);
+}
+
+void bch_cached_dev_detach(struct cached_dev *dc)
+{
+ lockdep_assert_held(&bch_register_lock);
+
+ if (atomic_read(&dc->disk.closing))
+ return;
+
+ if (atomic_xchg(&dc->disk.detaching, 1))
+ return;
+
+ /*
+ * Block the device from being closed and freed until we're finished
+ * detaching
+ */
+ closure_get(&dc->disk.cl);
+
+ bch_writeback_queue(dc);
+ cached_dev_put(dc);
+}
+
+int bch_cached_dev_attach(struct cached_dev *dc, struct cache_set *c)
+{
+ uint32_t rtime = cpu_to_le32(get_seconds());
+ struct uuid_entry *u;
+ char buf[BDEVNAME_SIZE];
+
+ bdevname(dc->bdev, buf);
+
+ if (memcmp(dc->sb.set_uuid, c->sb.set_uuid, 16))
+ return -ENOENT;
+
+ if (dc->disk.c) {
+ pr_err("Can't attach %s: already attached", buf);
+ return -EINVAL;
+ }
+
+ if (test_bit(CACHE_SET_STOPPING, &c->flags)) {
+ pr_err("Can't attach %s: shutting down", buf);
+ return -EINVAL;
+ }
+
+ if (dc->sb.block_size < c->sb.block_size) {
+ /* Will die */
+ pr_err("Couldn't attach %s: block size "
+ "less than set's block size", buf);
+ return -EINVAL;
+ }
+
+ u = uuid_find(c, dc->sb.uuid);
+
+ if (u &&
+ (BDEV_STATE(&dc->sb) == BDEV_STATE_STALE ||
+ BDEV_STATE(&dc->sb) == BDEV_STATE_NONE)) {
+ memcpy(u->uuid, invalid_uuid, 16);
+ u->invalidated = cpu_to_le32(get_seconds());
+ u = NULL;
+ }
+
+ if (!u) {
+ if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
+ pr_err("Couldn't find uuid for %s in set", buf);
+ return -ENOENT;
+ }
+
+ u = uuid_find_empty(c);
+ if (!u) {
+ pr_err("Not caching %s, no room for UUID", buf);
+ return -EINVAL;
+ }
+ }
+
+ /* Deadlocks since we're called via sysfs...
+ sysfs_remove_file(&dc->kobj, &sysfs_attach);
+ */
+
+ if (is_zero(u->uuid, 16)) {
+ struct closure cl;
+ closure_init_stack(&cl);
+
+ memcpy(u->uuid, dc->sb.uuid, 16);
+ memcpy(u->label, dc->sb.label, SB_LABEL_SIZE);
+ u->first_reg = u->last_reg = rtime;
+ bch_uuid_write(c);
+
+ memcpy(dc->sb.set_uuid, c->sb.set_uuid, 16);
+ SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
+
+ bch_write_bdev_super(dc, &cl);
+ closure_sync(&cl);
+ } else {
+ u->last_reg = rtime;
+ bch_uuid_write(c);
+ }
+
+ bcache_device_attach(&dc->disk, c, u - c->uuids);
+ bcache_device_link(&dc->disk, c, "bdev");
+ list_move(&dc->list, &c->cached_devs);
+ calc_cached_dev_sectors(c);
+
+ smp_wmb();
+ /*
+ * dc->c must be set before dc->count != 0 - paired with the mb in
+ * cached_dev_get()
+ */
+ atomic_set(&dc->count, 1);
+
+ if (BDEV_STATE(&dc->sb) == BDEV_STATE_DIRTY) {
+ atomic_set(&dc->has_dirty, 1);
+ atomic_inc(&dc->count);
+ bch_writeback_queue(dc);
+ }
+
+ bch_cached_dev_run(dc);
+
+ pr_info("Caching %s as %s on set %pU",
+ bdevname(dc->bdev, buf), dc->disk.disk->disk_name,
+ dc->disk.c->sb.set_uuid);
+ return 0;
+}
+
+void bch_cached_dev_release(struct kobject *kobj)
+{
+ struct cached_dev *dc = container_of(kobj, struct cached_dev,
+ disk.kobj);
+ kfree(dc);
+ module_put(THIS_MODULE);
+}
+
+static void cached_dev_free(struct closure *cl)
+{
+ struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
+
+ cancel_delayed_work_sync(&dc->writeback_rate_update);
+
+ mutex_lock(&bch_register_lock);
+
+ bcache_device_free(&dc->disk);
+ list_del(&dc->list);
+
+ mutex_unlock(&bch_register_lock);
+
+ if (!IS_ERR_OR_NULL(dc->bdev)) {
+ blk_sync_queue(bdev_get_queue(dc->bdev));
+ blkdev_put(dc->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+ }
+
+ wake_up(&unregister_wait);
+
+ kobject_put(&dc->disk.kobj);
+}
+
+static void cached_dev_flush(struct closure *cl)
+{
+ struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
+ struct bcache_device *d = &dc->disk;
+
+ bch_cache_accounting_destroy(&dc->accounting);
+ kobject_del(&d->kobj);
+
+ continue_at(cl, cached_dev_free, system_wq);
+}
+
+static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
+{
+ int err;
+ struct io *io;
+
+ closure_init(&dc->disk.cl, NULL);
+ set_closure_fn(&dc->disk.cl, cached_dev_flush, system_wq);
+
+ __module_get(THIS_MODULE);
+ INIT_LIST_HEAD(&dc->list);
+ kobject_init(&dc->disk.kobj, &bch_cached_dev_ktype);
+
+ bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
+
+ err = bcache_device_init(&dc->disk, block_size);
+ if (err)
+ goto err;
+
+ spin_lock_init(&dc->io_lock);
+ closure_init_unlocked(&dc->sb_write);
+ INIT_WORK(&dc->detach, cached_dev_detach_finish);
+
+ dc->sequential_merge = true;
+ dc->sequential_cutoff = 4 << 20;
+
+ INIT_LIST_HEAD(&dc->io_lru);
+ dc->sb_bio.bi_max_vecs = 1;
+ dc->sb_bio.bi_io_vec = dc->sb_bio.bi_inline_vecs;
+
+ for (io = dc->io; io < dc->io + RECENT_IO; io++) {
+ list_add(&io->lru, &dc->io_lru);
+ hlist_add_head(&io->hash, dc->io_hash + RECENT_IO);
+ }
+
+ bch_writeback_init_cached_dev(dc);
+ return 0;
+err:
+ bcache_device_stop(&dc->disk);
+ return err;
+}
+
+/* Cached device - bcache superblock */
+
+static const char *register_bdev(struct cache_sb *sb, struct page *sb_page,
+ struct block_device *bdev,
+ struct cached_dev *dc)
+{
+ char name[BDEVNAME_SIZE];
+ const char *err = "cannot allocate memory";
+ struct gendisk *g;
+ struct cache_set *c;
+
+ if (!dc || cached_dev_init(dc, sb->block_size << 9) != 0)
+ return err;
+
+ memcpy(&dc->sb, sb, sizeof(struct cache_sb));
+ dc->sb_bio.bi_io_vec[0].bv_page = sb_page;
+ dc->bdev = bdev;
+ dc->bdev->bd_holder = dc;
+
+ g = dc->disk.disk;
+
+ set_capacity(g, dc->bdev->bd_part->nr_sects - 16);
+
+ bch_cached_dev_request_init(dc);
+
+ err = "error creating kobject";
+ if (kobject_add(&dc->disk.kobj, &part_to_dev(bdev->bd_part)->kobj,
+ "bcache"))
+ goto err;
+ if (bch_cache_accounting_add_kobjs(&dc->accounting, &dc->disk.kobj))
+ goto err;
+
+ list_add(&dc->list, &uncached_devices);
+ list_for_each_entry(c, &bch_cache_sets, list)
+ bch_cached_dev_attach(dc, c);
+
+ if (BDEV_STATE(&dc->sb) == BDEV_STATE_NONE ||
+ BDEV_STATE(&dc->sb) == BDEV_STATE_STALE)
+ bch_cached_dev_run(dc);
+
+ return NULL;
+err:
+ kobject_put(&dc->disk.kobj);
+ pr_notice("error opening %s: %s", bdevname(bdev, name), err);
+ /*
+ * Return NULL instead of an error because kobject_put() cleans
+ * everything up
+ */
+ return NULL;
+}
+
+/* Flash only volumes */
+
+void bch_flash_dev_release(struct kobject *kobj)
+{
+ struct bcache_device *d = container_of(kobj, struct bcache_device,
+ kobj);
+ kfree(d);
+}
+
+static void flash_dev_free(struct closure *cl)
+{
+ struct bcache_device *d = container_of(cl, struct bcache_device, cl);
+ bcache_device_free(d);
+ kobject_put(&d->kobj);
+}
+
+static void flash_dev_flush(struct closure *cl)
+{
+ struct bcache_device *d = container_of(cl, struct bcache_device, cl);
+
+ sysfs_remove_link(&d->c->kobj, d->name);
+ sysfs_remove_link(&d->kobj, "cache");
+ kobject_del(&d->kobj);
+ continue_at(cl, flash_dev_free, system_wq);
+}
+
+static int flash_dev_run(struct cache_set *c, struct uuid_entry *u)
+{
+ struct bcache_device *d = kzalloc(sizeof(struct bcache_device),
+ GFP_KERNEL);
+ if (!d)
+ return -ENOMEM;
+
+ closure_init(&d->cl, NULL);
+ set_closure_fn(&d->cl, flash_dev_flush, system_wq);
+
+ kobject_init(&d->kobj, &bch_flash_dev_ktype);
+
+ if (bcache_device_init(d, block_bytes(c)))
+ goto err;
+
+ bcache_device_attach(d, c, u - c->uuids);
+ set_capacity(d->disk, u->sectors);
+ bch_flash_dev_request_init(d);
+ add_disk(d->disk);
+
+ if (kobject_add(&d->kobj, &disk_to_dev(d->disk)->kobj, "bcache"))
+ goto err;
+
+ bcache_device_link(d, c, "volume");
+
+ return 0;
+err:
+ kobject_put(&d->kobj);
+ return -ENOMEM;
+}
+
+static int flash_devs_run(struct cache_set *c)
+{
+ int ret = 0;
+ struct uuid_entry *u;
+
+ for (u = c->uuids;
+ u < c->uuids + c->nr_uuids && !ret;
+ u++)
+ if (UUID_FLASH_ONLY(u))
+ ret = flash_dev_run(c, u);
+
+ return ret;
+}
+
+int bch_flash_dev_create(struct cache_set *c, uint64_t size)
+{
+ struct uuid_entry *u;
+
+ if (test_bit(CACHE_SET_STOPPING, &c->flags))
+ return -EINTR;
+
+ u = uuid_find_empty(c);
+ if (!u) {
+ pr_err("Can't create volume, no room for UUID");
+ return -EINVAL;
+ }
+
+ get_random_bytes(u->uuid, 16);
+ memset(u->label, 0, 32);
+ u->first_reg = u->last_reg = cpu_to_le32(get_seconds());
+
+ SET_UUID_FLASH_ONLY(u, 1);
+ u->sectors = size >> 9;
+
+ bch_uuid_write(c);
+
+ return flash_dev_run(c, u);
+}
+
+/* Cache set */
+
+__printf(2, 3)
+bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
+{
+ va_list args;
+
+ if (test_bit(CACHE_SET_STOPPING, &c->flags))
+ return false;
+
+ /* XXX: we can be called from atomic context
+ acquire_console_sem();
+ */
+
+ printk(KERN_ERR "bcache: error on %pU: ", c->sb.set_uuid);
+
+ va_start(args, fmt);
+ vprintk(fmt, args);
+ va_end(args);
+
+ printk(", disabling caching\n");
+
+ bch_cache_set_unregister(c);
+ return true;
+}
+
+void bch_cache_set_release(struct kobject *kobj)
+{
+ struct cache_set *c = container_of(kobj, struct cache_set, kobj);
+ kfree(c);
+ module_put(THIS_MODULE);
+}
+
+static void cache_set_free(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, cl);
+ struct cache *ca;
+ unsigned i;
+
+ if (!IS_ERR_OR_NULL(c->debug))
+ debugfs_remove(c->debug);
+
+ bch_open_buckets_free(c);
+ bch_btree_cache_free(c);
+ bch_journal_free(c);
+
+ for_each_cache(ca, c, i)
+ if (ca)
+ kobject_put(&ca->kobj);
+
+ free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
+ free_pages((unsigned long) c->sort, ilog2(bucket_pages(c)));
+
+ kfree(c->fill_iter);
+ if (c->bio_split)
+ bioset_free(c->bio_split);
+ if (c->bio_meta)
+ mempool_destroy(c->bio_meta);
+ if (c->search)
+ mempool_destroy(c->search);
+ kfree(c->devices);
+
+ mutex_lock(&bch_register_lock);
+ list_del(&c->list);
+ mutex_unlock(&bch_register_lock);
+
+ pr_info("Cache set %pU unregistered", c->sb.set_uuid);
+ wake_up(&unregister_wait);
+
+ closure_debug_destroy(&c->cl);
+ kobject_put(&c->kobj);
+}
+
+static void cache_set_flush(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, caching);
+ struct btree *b;
+
+ /* Shut down allocator threads */
+ set_bit(CACHE_SET_STOPPING_2, &c->flags);
+ wake_up(&c->alloc_wait);
+
+ bch_cache_accounting_destroy(&c->accounting);
+
+ kobject_put(&c->internal);
+ kobject_del(&c->kobj);
+
+ if (!IS_ERR_OR_NULL(c->root))
+ list_add(&c->root->list, &c->btree_cache);
+
+ /* Should skip this if we're unregistering because of an error */
+ list_for_each_entry(b, &c->btree_cache, list)
+ if (btree_node_dirty(b))
+ bch_btree_write(b, true, NULL);
+
+ closure_return(cl);
+}
+
+static void __cache_set_unregister(struct closure *cl)
+{
+ struct cache_set *c = container_of(cl, struct cache_set, caching);
+ struct cached_dev *dc, *t;
+ size_t i;
+
+ mutex_lock(&bch_register_lock);
+
+ if (test_bit(CACHE_SET_UNREGISTERING, &c->flags))
+ list_for_each_entry_safe(dc, t, &c->cached_devs, list)
+ bch_cached_dev_detach(dc);
+
+ for (i = 0; i < c->nr_uuids; i++)
+ if (c->devices[i] && UUID_FLASH_ONLY(&c->uuids[i]))
+ bcache_device_stop(c->devices[i]);
+
+ mutex_unlock(&bch_register_lock);
+
+ continue_at(cl, cache_set_flush, system_wq);
+}
+
+void bch_cache_set_stop(struct cache_set *c)
+{
+ if (!test_and_set_bit(CACHE_SET_STOPPING, &c->flags))
+ closure_queue(&c->caching);
+}
+
+void bch_cache_set_unregister(struct cache_set *c)
+{
+ set_bit(CACHE_SET_UNREGISTERING, &c->flags);
+ bch_cache_set_stop(c);
+}
+
+#define alloc_bucket_pages(gfp, c) \
+ ((void *) __get_free_pages(__GFP_ZERO|gfp, ilog2(bucket_pages(c))))
+
+struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
+{
+ int iter_size;
+ struct cache_set *c = kzalloc(sizeof(struct cache_set), GFP_KERNEL);
+ if (!c)
+ return NULL;
+
+ __module_get(THIS_MODULE);
+ closure_init(&c->cl, NULL);
+ set_closure_fn(&c->cl, cache_set_free, system_wq);
+
+ closure_init(&c->caching, &c->cl);
+ set_closure_fn(&c->caching, __cache_set_unregister, system_wq);
+
+ /* Maybe create continue_at_noreturn() and use it here? */
+ closure_set_stopped(&c->cl);
+ closure_put(&c->cl);
+
+ kobject_init(&c->kobj, &bch_cache_set_ktype);
+ kobject_init(&c->internal, &bch_cache_set_internal_ktype);
+
+ bch_cache_accounting_init(&c->accounting, &c->cl);
+
+ memcpy(c->sb.set_uuid, sb->set_uuid, 16);
+ c->sb.block_size = sb->block_size;
+ c->sb.bucket_size = sb->bucket_size;
+ c->sb.nr_in_set = sb->nr_in_set;
+ c->sb.last_mount = sb->last_mount;
+ c->bucket_bits = ilog2(sb->bucket_size);
+ c->block_bits = ilog2(sb->block_size);
+ c->nr_uuids = bucket_bytes(c) / sizeof(struct uuid_entry);
+
+ c->btree_pages = c->sb.bucket_size / PAGE_SECTORS;
+ if (c->btree_pages > BTREE_MAX_PAGES)
+ c->btree_pages = max_t(int, c->btree_pages / 4,
+ BTREE_MAX_PAGES);
+
+ init_waitqueue_head(&c->alloc_wait);
+ mutex_init(&c->bucket_lock);
+ mutex_init(&c->fill_lock);
+ mutex_init(&c->sort_lock);
+ spin_lock_init(&c->sort_time_lock);
+ closure_init_unlocked(&c->sb_write);
+ closure_init_unlocked(&c->uuid_write);
+ spin_lock_init(&c->btree_read_time_lock);
+ bch_moving_init_cache_set(c);
+
+ INIT_LIST_HEAD(&c->list);
+ INIT_LIST_HEAD(&c->cached_devs);
+ INIT_LIST_HEAD(&c->btree_cache);
+ INIT_LIST_HEAD(&c->btree_cache_freeable);
+ INIT_LIST_HEAD(&c->btree_cache_freed);
+ INIT_LIST_HEAD(&c->data_buckets);
+
+ c->search = mempool_create_slab_pool(32, bch_search_cache);
+ if (!c->search)
+ goto err;
+
+ iter_size = (sb->bucket_size / sb->block_size + 1) *
+ sizeof(struct btree_iter_set);
+
+ if (!(c->devices = kzalloc(c->nr_uuids * sizeof(void *), GFP_KERNEL)) ||
+ !(c->bio_meta = mempool_create_kmalloc_pool(2,
+ sizeof(struct bbio) + sizeof(struct bio_vec) *
+ bucket_pages(c))) ||
+ !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
+ !(c->fill_iter = kmalloc(iter_size, GFP_KERNEL)) ||
+ !(c->sort = alloc_bucket_pages(GFP_KERNEL, c)) ||
+ !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
+ bch_journal_alloc(c) ||
+ bch_btree_cache_alloc(c) ||
+ bch_open_buckets_alloc(c))
+ goto err;
+
+ c->fill_iter->size = sb->bucket_size / sb->block_size;
+
+ c->congested_read_threshold_us = 2000;
+ c->congested_write_threshold_us = 20000;
+ c->error_limit = 8 << IO_ERROR_SHIFT;
+
+ return c;
+err:
+ bch_cache_set_unregister(c);
+ return NULL;
+}
+
+static void run_cache_set(struct cache_set *c)
+{
+ const char *err = "cannot allocate memory";
+ struct cached_dev *dc, *t;
+ struct cache *ca;
+ unsigned i;
+
+ struct btree_op op;
+ bch_btree_op_init_stack(&op);
+ op.lock = SHRT_MAX;
+
+ for_each_cache(ca, c, i)
+ c->nbuckets += ca->sb.nbuckets;
+
+ if (CACHE_SYNC(&c->sb)) {
+ LIST_HEAD(journal);
+ struct bkey *k;
+ struct jset *j;
+
+ err = "cannot allocate memory for journal";
+ if (bch_journal_read(c, &journal, &op))
+ goto err;
+
+ pr_debug("btree_journal_read() done");
+
+ err = "no journal entries found";
+ if (list_empty(&journal))
+ goto err;
+
+ j = &list_entry(journal.prev, struct journal_replay, list)->j;
+
+ err = "IO error reading priorities";
+ for_each_cache(ca, c, i)
+ prio_read(ca, j->prio_bucket[ca->sb.nr_this_dev]);
+
+ /*
+ * If prio_read() fails it'll call cache_set_error and we'll
+ * tear everything down right away, but if we perhaps checked
+ * sooner we could avoid journal replay.
+ */
+
+ k = &j->btree_root;
+
+ err = "bad btree root";
+ if (__bch_ptr_invalid(c, j->btree_level + 1, k))
+ goto err;
+
+ err = "error reading btree root";
+ c->root = bch_btree_node_get(c, k, j->btree_level, &op);
+ if (IS_ERR_OR_NULL(c->root))
+ goto err;
+
+ list_del_init(&c->root->list);
+ rw_unlock(true, c->root);
+
+ err = uuid_read(c, j, &op.cl);
+ if (err)
+ goto err;
+
+ err = "error in recovery";
+ if (bch_btree_check(c, &op))
+ goto err;
+
+ bch_journal_mark(c, &journal);
+ bch_btree_gc_finish(c);
+ pr_debug("btree_check() done");
+
+ /*
+ * bcache_journal_next() can't happen sooner, or
+ * btree_gc_finish() will give spurious errors about last_gc >
+ * gc_gen - this is a hack but oh well.
+ */
+ bch_journal_next(&c->journal);
+
+ for_each_cache(ca, c, i)
+ closure_call(&ca->alloc, bch_allocator_thread,
+ system_wq, &c->cl);
+
+ /*
+ * First place it's safe to allocate: btree_check() and
+ * btree_gc_finish() have to run before we have buckets to
+ * allocate, and bch_bucket_alloc_set() might cause a journal
+ * entry to be written so bcache_journal_next() has to be called
+ * first.
+ *
+ * If the uuids were in the old format we have to rewrite them
+ * before the next journal entry is written:
+ */
+ if (j->version < BCACHE_JSET_VERSION_UUID)
+ __uuid_write(c);
+
+ bch_journal_replay(c, &journal, &op);
+ } else {
+ pr_notice("invalidating existing data");
+ /* Don't want invalidate_buckets() to queue a gc yet */
+ closure_lock(&c->gc, NULL);
+
+ for_each_cache(ca, c, i) {
+ unsigned j;
+
+ ca->sb.keys = clamp_t(int, ca->sb.nbuckets >> 7,
+ 2, SB_JOURNAL_BUCKETS);
+
+ for (j = 0; j < ca->sb.keys; j++)
+ ca->sb.d[j] = ca->sb.first_bucket + j;
+ }
+
+ bch_btree_gc_finish(c);
+
+ for_each_cache(ca, c, i)
+ closure_call(&ca->alloc, bch_allocator_thread,
+ ca->alloc_workqueue, &c->cl);
+
+ mutex_lock(&c->bucket_lock);
+ for_each_cache(ca, c, i)
+ bch_prio_write(ca);
+ mutex_unlock(&c->bucket_lock);
+
+ wake_up(&c->alloc_wait);
+
+ err = "cannot allocate new UUID bucket";
+ if (__uuid_write(c))
+ goto err_unlock_gc;
+
+ err = "cannot allocate new btree root";
+ c->root = bch_btree_node_alloc(c, 0, &op.cl);
+ if (IS_ERR_OR_NULL(c->root))
+ goto err_unlock_gc;
+
+ bkey_copy_key(&c->root->key, &MAX_KEY);
+ bch_btree_write(c->root, true, &op);
+
+ bch_btree_set_root(c->root);
+ rw_unlock(true, c->root);
+
+ /*
+ * We don't want to write the first journal entry until
+ * everything is set up - fortunately journal entries won't be
+ * written until the SET_CACHE_SYNC() here:
+ */
+ SET_CACHE_SYNC(&c->sb, true);
+
+ bch_journal_next(&c->journal);
+ bch_journal_meta(c, &op.cl);
+
+ /* Unlock */
+ closure_set_stopped(&c->gc.cl);
+ closure_put(&c->gc.cl);
+ }
+
+ closure_sync(&op.cl);
+ c->sb.last_mount = get_seconds();
+ bcache_write_super(c);
+
+ list_for_each_entry_safe(dc, t, &uncached_devices, list)
+ bch_cached_dev_attach(dc, c);
+
+ flash_devs_run(c);
+
+ return;
+err_unlock_gc:
+ closure_set_stopped(&c->gc.cl);
+ closure_put(&c->gc.cl);
+err:
+ closure_sync(&op.cl);
+ /* XXX: test this, it's broken */
+ bch_cache_set_error(c, err);
+}
+
+static bool can_attach_cache(struct cache *ca, struct cache_set *c)
+{
+ return ca->sb.block_size == c->sb.block_size &&
+ ca->sb.bucket_size == c->sb.block_size &&
+ ca->sb.nr_in_set == c->sb.nr_in_set;
+}
+
+static const char *register_cache_set(struct cache *ca)
+{
+ char buf[12];
+ const char *err = "cannot allocate memory";
+ struct cache_set *c;
+
+ list_for_each_entry(c, &bch_cache_sets, list)
+ if (!memcmp(c->sb.set_uuid, ca->sb.set_uuid, 16)) {
+ if (c->cache[ca->sb.nr_this_dev])
+ return "duplicate cache set member";
+
+ if (!can_attach_cache(ca, c))
+ return "cache sb does not match set";
+
+ if (!CACHE_SYNC(&ca->sb))
+ SET_CACHE_SYNC(&c->sb, false);
+
+ goto found;
+ }
+
+ c = bch_cache_set_alloc(&ca->sb);
+ if (!c)
+ return err;
+
+ err = "error creating kobject";
+ if (kobject_add(&c->kobj, bcache_kobj, "%pU", c->sb.set_uuid) ||
+ kobject_add(&c->internal, &c->kobj, "internal"))
+ goto err;
+
+ if (bch_cache_accounting_add_kobjs(&c->accounting, &c->kobj))
+ goto err;
+
+ bch_debug_init_cache_set(c);
+
+ list_add(&c->list, &bch_cache_sets);
+found:
+ sprintf(buf, "cache%i", ca->sb.nr_this_dev);
+ if (sysfs_create_link(&ca->kobj, &c->kobj, "set") ||
+ sysfs_create_link(&c->kobj, &ca->kobj, buf))
+ goto err;
+
+ if (ca->sb.seq > c->sb.seq) {
+ c->sb.version = ca->sb.version;
+ memcpy(c->sb.set_uuid, ca->sb.set_uuid, 16);
+ c->sb.flags = ca->sb.flags;
+ c->sb.seq = ca->sb.seq;
+ pr_debug("set version = %llu", c->sb.version);
+ }
+
+ ca->set = c;
+ ca->set->cache[ca->sb.nr_this_dev] = ca;
+ c->cache_by_alloc[c->caches_loaded++] = ca;
+
+ if (c->caches_loaded == c->sb.nr_in_set)
+ run_cache_set(c);
+
+ return NULL;
+err:
+ bch_cache_set_unregister(c);
+ return err;
+}
+
+/* Cache device */
+
+void bch_cache_release(struct kobject *kobj)
+{
+ struct cache *ca = container_of(kobj, struct cache, kobj);
+
+ if (ca->set)
+ ca->set->cache[ca->sb.nr_this_dev] = NULL;
+
+ bch_cache_allocator_exit(ca);
+
+ bio_split_pool_free(&ca->bio_split_hook);
+
+ if (ca->alloc_workqueue)
+ destroy_workqueue(ca->alloc_workqueue);
+
+ free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
+ kfree(ca->prio_buckets);
+ vfree(ca->buckets);
+
+ free_heap(&ca->heap);
+ free_fifo(&ca->unused);
+ free_fifo(&ca->free_inc);
+ free_fifo(&ca->free);
+
+ if (ca->sb_bio.bi_inline_vecs[0].bv_page)
+ put_page(ca->sb_bio.bi_io_vec[0].bv_page);
+
+ if (!IS_ERR_OR_NULL(ca->bdev)) {
+ blk_sync_queue(bdev_get_queue(ca->bdev));
+ blkdev_put(ca->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+ }
+
+ kfree(ca);
+ module_put(THIS_MODULE);
+}
+
+static int cache_alloc(struct cache_sb *sb, struct cache *ca)
+{
+ size_t free;
+ struct bucket *b;
+
+ if (!ca)
+ return -ENOMEM;
+
+ __module_get(THIS_MODULE);
+ kobject_init(&ca->kobj, &bch_cache_ktype);
+
+ memcpy(&ca->sb, sb, sizeof(struct cache_sb));
+
+ INIT_LIST_HEAD(&ca->discards);
+
+ bio_init(&ca->sb_bio);
+ ca->sb_bio.bi_max_vecs = 1;
+ ca->sb_bio.bi_io_vec = ca->sb_bio.bi_inline_vecs;
+
+ bio_init(&ca->journal.bio);
+ ca->journal.bio.bi_max_vecs = 8;
+ ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs;
+
+ free = roundup_pow_of_two(ca->sb.nbuckets) >> 9;
+ free = max_t(size_t, free, (prio_buckets(ca) + 8) * 2);
+
+ if (!init_fifo(&ca->free, free, GFP_KERNEL) ||
+ !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) ||
+ !init_fifo(&ca->unused, free << 2, GFP_KERNEL) ||
+ !init_heap(&ca->heap, free << 3, GFP_KERNEL) ||
+ !(ca->buckets = vmalloc(sizeof(struct bucket) *
+ ca->sb.nbuckets)) ||
+ !(ca->prio_buckets = kzalloc(sizeof(uint64_t) * prio_buckets(ca) *
+ 2, GFP_KERNEL)) ||
+ !(ca->disk_buckets = alloc_bucket_pages(GFP_KERNEL, ca)) ||
+ !(ca->alloc_workqueue = alloc_workqueue("bch_allocator", 0, 1)) ||
+ bio_split_pool_init(&ca->bio_split_hook))
+ goto err;
+
+ ca->prio_last_buckets = ca->prio_buckets + prio_buckets(ca);
+
+ memset(ca->buckets, 0, ca->sb.nbuckets * sizeof(struct bucket));
+ for_each_bucket(b, ca)
+ atomic_set(&b->pin, 0);
+
+ if (bch_cache_allocator_init(ca))
+ goto err;
+
+ return 0;
+err:
+ kobject_put(&ca->kobj);
+ return -ENOMEM;
+}
+
+static const char *register_cache(struct cache_sb *sb, struct page *sb_page,
+ struct block_device *bdev, struct cache *ca)
+{
+ char name[BDEVNAME_SIZE];
+ const char *err = "cannot allocate memory";
+
+ if (cache_alloc(sb, ca) != 0)
+ return err;
+
+ ca->sb_bio.bi_io_vec[0].bv_page = sb_page;
+ ca->bdev = bdev;
+ ca->bdev->bd_holder = ca;
+
+ if (blk_queue_discard(bdev_get_queue(ca->bdev)))
+ ca->discard = CACHE_DISCARD(&ca->sb);
+
+ err = "error creating kobject";
+ if (kobject_add(&ca->kobj, &part_to_dev(bdev->bd_part)->kobj, "bcache"))
+ goto err;
+
+ err = register_cache_set(ca);
+ if (err)
+ goto err;
+
+ pr_info("registered cache device %s", bdevname(bdev, name));
+
+ return NULL;
+err:
+ kobject_put(&ca->kobj);
+ pr_info("error opening %s: %s", bdevname(bdev, name), err);
+ /* Return NULL instead of an error because kobject_put() cleans
+ * everything up
+ */
+ return NULL;
+}
+
+/* Global interfaces/init */
+
+static ssize_t register_bcache(struct kobject *, struct kobj_attribute *,
+ const char *, size_t);
+
+kobj_attribute_write(register, register_bcache);
+kobj_attribute_write(register_quiet, register_bcache);
+
+static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
+ const char *buffer, size_t size)
+{
+ ssize_t ret = size;
+ const char *err = "cannot allocate memory";
+ char *path = NULL;
+ struct cache_sb *sb = NULL;
+ struct block_device *bdev = NULL;
+ struct page *sb_page = NULL;
+
+ if (!try_module_get(THIS_MODULE))
+ return -EBUSY;
+
+ mutex_lock(&bch_register_lock);
+
+ if (!(path = kstrndup(buffer, size, GFP_KERNEL)) ||
+ !(sb = kmalloc(sizeof(struct cache_sb), GFP_KERNEL)))
+ goto err;
+
+ err = "failed to open device";
+ bdev = blkdev_get_by_path(strim(path),
+ FMODE_READ|FMODE_WRITE|FMODE_EXCL,
+ sb);
+ if (bdev == ERR_PTR(-EBUSY))
+ err = "device busy";
+
+ if (IS_ERR(bdev) ||
+ set_blocksize(bdev, 4096))
+ goto err;
+
+ err = read_super(sb, bdev, &sb_page);
+ if (err)
+ goto err_close;
+
+ if (sb->version == CACHE_BACKING_DEV) {
+ struct cached_dev *dc = kzalloc(sizeof(*dc), GFP_KERNEL);
+
+ err = register_bdev(sb, sb_page, bdev, dc);
+ } else {
+ struct cache *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+
+ err = register_cache(sb, sb_page, bdev, ca);
+ }
+
+ if (err) {
+ /* register_(bdev|cache) will only return an error if they
+ * didn't get far enough to create the kobject - if they did,
+ * the kobject destructor will do this cleanup.
+ */
+ put_page(sb_page);
+err_close:
+ blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+err:
+ if (attr != &ksysfs_register_quiet)
+ pr_info("error opening %s: %s", path, err);
+ ret = -EINVAL;
+ }
+
+ kfree(sb);
+ kfree(path);
+ mutex_unlock(&bch_register_lock);
+ module_put(THIS_MODULE);
+ return ret;
+}
+
+static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
+{
+ if (code == SYS_DOWN ||
+ code == SYS_HALT ||
+ code == SYS_POWER_OFF) {
+ DEFINE_WAIT(wait);
+ unsigned long start = jiffies;
+ bool stopped = false;
+
+ struct cache_set *c, *tc;
+ struct cached_dev *dc, *tdc;
+
+ mutex_lock(&bch_register_lock);
+
+ if (list_empty(&bch_cache_sets) &&
+ list_empty(&uncached_devices))
+ goto out;
+
+ pr_info("Stopping all devices:");
+
+ list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
+ bch_cache_set_stop(c);
+
+ list_for_each_entry_safe(dc, tdc, &uncached_devices, list)
+ bcache_device_stop(&dc->disk);
+
+ /* What's a condition variable? */
+ while (1) {
+ long timeout = start + 2 * HZ - jiffies;
+
+ stopped = list_empty(&bch_cache_sets) &&
+ list_empty(&uncached_devices);
+
+ if (timeout < 0 || stopped)
+ break;
+
+ prepare_to_wait(&unregister_wait, &wait,
+ TASK_UNINTERRUPTIBLE);
+
+ mutex_unlock(&bch_register_lock);
+ schedule_timeout(timeout);
+ mutex_lock(&bch_register_lock);
+ }
+
+ finish_wait(&unregister_wait, &wait);
+
+ if (stopped)
+ pr_info("All devices stopped");
+ else
+ pr_notice("Timeout waiting for devices to be closed");
+out:
+ mutex_unlock(&bch_register_lock);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block reboot = {
+ .notifier_call = bcache_reboot,
+ .priority = INT_MAX, /* before any real devices */
+};
+
+static void bcache_exit(void)
+{
+ bch_debug_exit();
+ bch_writeback_exit();
+ bch_request_exit();
+ bch_btree_exit();
+ if (bcache_kobj)
+ kobject_put(bcache_kobj);
+ if (bcache_wq)
+ destroy_workqueue(bcache_wq);
+ unregister_blkdev(bcache_major, "bcache");
+ unregister_reboot_notifier(&reboot);
+}
+
+static int __init bcache_init(void)
+{
+ static const struct attribute *files[] = {
+ &ksysfs_register.attr,
+ &ksysfs_register_quiet.attr,
+ NULL
+ };
+
+ mutex_init(&bch_register_lock);
+ init_waitqueue_head(&unregister_wait);
+ register_reboot_notifier(&reboot);
+
+ bcache_major = register_blkdev(0, "bcache");
+ if (bcache_major < 0)
+ return bcache_major;
+
+ if (!(bcache_wq = create_workqueue("bcache")) ||
+ !(bcache_kobj = kobject_create_and_add("bcache", fs_kobj)) ||
+ sysfs_create_files(bcache_kobj, files) ||
+ bch_btree_init() ||
+ bch_request_init() ||
+ bch_writeback_init() ||
+ bch_debug_init(bcache_kobj))
+ goto err;
+
+ return 0;
+err:
+ bcache_exit();
+ return -ENOMEM;
+}
+
+module_exit(bcache_exit);
+module_init(bcache_init);
--- /dev/null
+/*
+ * bcache sysfs interfaces
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "sysfs.h"
+#include "btree.h"
+#include "request.h"
+
+#include <linux/sort.h>
+
+static const char * const cache_replacement_policies[] = {
+ "lru",
+ "fifo",
+ "random",
+ NULL
+};
+
+write_attribute(attach);
+write_attribute(detach);
+write_attribute(unregister);
+write_attribute(stop);
+write_attribute(clear_stats);
+write_attribute(trigger_gc);
+write_attribute(prune_cache);
+write_attribute(flash_vol_create);
+
+read_attribute(bucket_size);
+read_attribute(block_size);
+read_attribute(nbuckets);
+read_attribute(tree_depth);
+read_attribute(root_usage_percent);
+read_attribute(priority_stats);
+read_attribute(btree_cache_size);
+read_attribute(btree_cache_max_chain);
+read_attribute(cache_available_percent);
+read_attribute(written);
+read_attribute(btree_written);
+read_attribute(metadata_written);
+read_attribute(active_journal_entries);
+
+sysfs_time_stats_attribute(btree_gc, sec, ms);
+sysfs_time_stats_attribute(btree_split, sec, us);
+sysfs_time_stats_attribute(btree_sort, ms, us);
+sysfs_time_stats_attribute(btree_read, ms, us);
+sysfs_time_stats_attribute(try_harder, ms, us);
+
+read_attribute(btree_nodes);
+read_attribute(btree_used_percent);
+read_attribute(average_key_size);
+read_attribute(dirty_data);
+read_attribute(bset_tree_stats);
+
+read_attribute(state);
+read_attribute(cache_read_races);
+read_attribute(writeback_keys_done);
+read_attribute(writeback_keys_failed);
+read_attribute(io_errors);
+read_attribute(congested);
+rw_attribute(congested_read_threshold_us);
+rw_attribute(congested_write_threshold_us);
+
+rw_attribute(sequential_cutoff);
+rw_attribute(sequential_merge);
+rw_attribute(data_csum);
+rw_attribute(cache_mode);
+rw_attribute(writeback_metadata);
+rw_attribute(writeback_running);
+rw_attribute(writeback_percent);
+rw_attribute(writeback_delay);
+rw_attribute(writeback_rate);
+
+rw_attribute(writeback_rate_update_seconds);
+rw_attribute(writeback_rate_d_term);
+rw_attribute(writeback_rate_p_term_inverse);
+rw_attribute(writeback_rate_d_smooth);
+read_attribute(writeback_rate_debug);
+
+rw_attribute(synchronous);
+rw_attribute(journal_delay_ms);
+rw_attribute(discard);
+rw_attribute(running);
+rw_attribute(label);
+rw_attribute(readahead);
+rw_attribute(io_error_limit);
+rw_attribute(io_error_halflife);
+rw_attribute(verify);
+rw_attribute(key_merging_disabled);
+rw_attribute(gc_always_rewrite);
+rw_attribute(freelist_percent);
+rw_attribute(cache_replacement_policy);
+rw_attribute(btree_shrinker_disabled);
+rw_attribute(copy_gc_enabled);
+rw_attribute(size);
+
+SHOW(__bch_cached_dev)
+{
+ struct cached_dev *dc = container_of(kobj, struct cached_dev,
+ disk.kobj);
+ const char *states[] = { "no cache", "clean", "dirty", "inconsistent" };
+
+#define var(stat) (dc->stat)
+
+ if (attr == &sysfs_cache_mode)
+ return snprint_string_list(buf, PAGE_SIZE,
+ bch_cache_modes + 1,
+ BDEV_CACHE_MODE(&dc->sb));
+
+ sysfs_printf(data_csum, "%i", dc->disk.data_csum);
+ var_printf(verify, "%i");
+ var_printf(writeback_metadata, "%i");
+ var_printf(writeback_running, "%i");
+ var_print(writeback_delay);
+ var_print(writeback_percent);
+ sysfs_print(writeback_rate, dc->writeback_rate.rate);
+
+ var_print(writeback_rate_update_seconds);
+ var_print(writeback_rate_d_term);
+ var_print(writeback_rate_p_term_inverse);
+ var_print(writeback_rate_d_smooth);
+
+ if (attr == &sysfs_writeback_rate_debug) {
+ char dirty[20];
+ char derivative[20];
+ char target[20];
+ hprint(dirty,
+ atomic_long_read(&dc->disk.sectors_dirty) << 9);
+ hprint(derivative, dc->writeback_rate_derivative << 9);
+ hprint(target, dc->writeback_rate_target << 9);
+
+ return sprintf(buf,
+ "rate:\t\t%u\n"
+ "change:\t\t%i\n"
+ "dirty:\t\t%s\n"
+ "derivative:\t%s\n"
+ "target:\t\t%s\n",
+ dc->writeback_rate.rate,
+ dc->writeback_rate_change,
+ dirty, derivative, target);
+ }
+
+ sysfs_hprint(dirty_data,
+ atomic_long_read(&dc->disk.sectors_dirty) << 9);
+
+ var_printf(sequential_merge, "%i");
+ var_hprint(sequential_cutoff);
+ var_hprint(readahead);
+
+ sysfs_print(running, atomic_read(&dc->running));
+ sysfs_print(state, states[BDEV_STATE(&dc->sb)]);
+
+ if (attr == &sysfs_label) {
+ memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
+ buf[SB_LABEL_SIZE + 1] = '\0';
+ strcat(buf, "\n");
+ return strlen(buf);
+ }
+
+#undef var
+ return 0;
+}
+SHOW_LOCKED(bch_cached_dev)
+
+STORE(__cached_dev)
+{
+ struct cached_dev *dc = container_of(kobj, struct cached_dev,
+ disk.kobj);
+ unsigned v = size;
+ struct cache_set *c;
+
+#define d_strtoul(var) sysfs_strtoul(var, dc->var)
+#define d_strtoi_h(var) sysfs_hatoi(var, dc->var)
+
+ sysfs_strtoul(data_csum, dc->disk.data_csum);
+ d_strtoul(verify);
+ d_strtoul(writeback_metadata);
+ d_strtoul(writeback_running);
+ d_strtoul(writeback_delay);
+ sysfs_strtoul_clamp(writeback_rate,
+ dc->writeback_rate.rate, 1, 1000000);
+ sysfs_strtoul_clamp(writeback_percent, dc->writeback_percent, 0, 40);
+
+ d_strtoul(writeback_rate_update_seconds);
+ d_strtoul(writeback_rate_d_term);
+ d_strtoul(writeback_rate_p_term_inverse);
+ sysfs_strtoul_clamp(writeback_rate_p_term_inverse,
+ dc->writeback_rate_p_term_inverse, 1, INT_MAX);
+ d_strtoul(writeback_rate_d_smooth);
+
+ d_strtoul(sequential_merge);
+ d_strtoi_h(sequential_cutoff);
+ d_strtoi_h(readahead);
+
+ if (attr == &sysfs_clear_stats)
+ bch_cache_accounting_clear(&dc->accounting);
+
+ if (attr == &sysfs_running &&
+ strtoul_or_return(buf))
+ bch_cached_dev_run(dc);
+
+ if (attr == &sysfs_cache_mode) {
+ ssize_t v = read_string_list(buf, bch_cache_modes + 1);
+
+ if (v < 0)
+ return v;
+
+ if ((unsigned) v != BDEV_CACHE_MODE(&dc->sb)) {
+ SET_BDEV_CACHE_MODE(&dc->sb, v);
+ bch_write_bdev_super(dc, NULL);
+ }
+ }
+
+ if (attr == &sysfs_label) {
+ memcpy(dc->sb.label, buf, SB_LABEL_SIZE);
+ bch_write_bdev_super(dc, NULL);
+ if (dc->disk.c) {
+ memcpy(dc->disk.c->uuids[dc->disk.id].label,
+ buf, SB_LABEL_SIZE);
+ bch_uuid_write(dc->disk.c);
+ }
+ }
+
+ if (attr == &sysfs_attach) {
+ if (parse_uuid(buf, dc->sb.set_uuid) < 16)
+ return -EINVAL;
+
+ list_for_each_entry(c, &bch_cache_sets, list) {
+ v = bch_cached_dev_attach(dc, c);
+ if (!v)
+ return size;
+ }
+
+ pr_err("Can't attach %s: cache set not found", buf);
+ size = v;
+ }
+
+ if (attr == &sysfs_detach && dc->disk.c)
+ bch_cached_dev_detach(dc);
+
+ if (attr == &sysfs_stop)
+ bcache_device_stop(&dc->disk);
+
+ return size;
+}
+
+STORE(bch_cached_dev)
+{
+ struct cached_dev *dc = container_of(kobj, struct cached_dev,
+ disk.kobj);
+
+ mutex_lock(&bch_register_lock);
+ size = __cached_dev_store(kobj, attr, buf, size);
+
+ if (attr == &sysfs_writeback_running)
+ bch_writeback_queue(dc);
+
+ if (attr == &sysfs_writeback_percent)
+ schedule_delayed_work(&dc->writeback_rate_update,
+ dc->writeback_rate_update_seconds * HZ);
+
+ mutex_unlock(&bch_register_lock);
+ return size;
+}
+
+static struct attribute *bch_cached_dev_files[] = {
+ &sysfs_attach,
+ &sysfs_detach,
+ &sysfs_stop,
+#if 0
+ &sysfs_data_csum,
+#endif
+ &sysfs_cache_mode,
+ &sysfs_writeback_metadata,
+ &sysfs_writeback_running,
+ &sysfs_writeback_delay,
+ &sysfs_writeback_percent,
+ &sysfs_writeback_rate,
+ &sysfs_writeback_rate_update_seconds,
+ &sysfs_writeback_rate_d_term,
+ &sysfs_writeback_rate_p_term_inverse,
+ &sysfs_writeback_rate_d_smooth,
+ &sysfs_writeback_rate_debug,
+ &sysfs_dirty_data,
+ &sysfs_sequential_cutoff,
+ &sysfs_sequential_merge,
+ &sysfs_clear_stats,
+ &sysfs_running,
+ &sysfs_state,
+ &sysfs_label,
+ &sysfs_readahead,
+#ifdef CONFIG_BCACHE_DEBUG
+ &sysfs_verify,
+#endif
+ NULL
+};
+KTYPE(bch_cached_dev);
+
+SHOW(bch_flash_dev)
+{
+ struct bcache_device *d = container_of(kobj, struct bcache_device,
+ kobj);
+ struct uuid_entry *u = &d->c->uuids[d->id];
+
+ sysfs_printf(data_csum, "%i", d->data_csum);
+ sysfs_hprint(size, u->sectors << 9);
+
+ if (attr == &sysfs_label) {
+ memcpy(buf, u->label, SB_LABEL_SIZE);
+ buf[SB_LABEL_SIZE + 1] = '\0';
+ strcat(buf, "\n");
+ return strlen(buf);
+ }
+
+ return 0;
+}
+
+STORE(__bch_flash_dev)
+{
+ struct bcache_device *d = container_of(kobj, struct bcache_device,
+ kobj);
+ struct uuid_entry *u = &d->c->uuids[d->id];
+
+ sysfs_strtoul(data_csum, d->data_csum);
+
+ if (attr == &sysfs_size) {
+ uint64_t v;
+ strtoi_h_or_return(buf, v);
+
+ u->sectors = v >> 9;
+ bch_uuid_write(d->c);
+ set_capacity(d->disk, u->sectors);
+ }
+
+ if (attr == &sysfs_label) {
+ memcpy(u->label, buf, SB_LABEL_SIZE);
+ bch_uuid_write(d->c);
+ }
+
+ if (attr == &sysfs_unregister) {
+ atomic_set(&d->detaching, 1);
+ bcache_device_stop(d);
+ }
+
+ return size;
+}
+STORE_LOCKED(bch_flash_dev)
+
+static struct attribute *bch_flash_dev_files[] = {
+ &sysfs_unregister,
+#if 0
+ &sysfs_data_csum,
+#endif
+ &sysfs_label,
+ &sysfs_size,
+ NULL
+};
+KTYPE(bch_flash_dev);
+
+SHOW(__bch_cache_set)
+{
+ unsigned root_usage(struct cache_set *c)
+ {
+ unsigned bytes = 0;
+ struct bkey *k;
+ struct btree *b;
+ struct btree_iter iter;
+
+ goto lock_root;
+
+ do {
+ rw_unlock(false, b);
+lock_root:
+ b = c->root;
+ rw_lock(false, b, b->level);
+ } while (b != c->root);
+
+ for_each_key_filter(b, k, &iter, bch_ptr_bad)
+ bytes += bkey_bytes(k);
+
+ rw_unlock(false, b);
+
+ return (bytes * 100) / btree_bytes(c);
+ }
+
+ size_t cache_size(struct cache_set *c)
+ {
+ size_t ret = 0;
+ struct btree *b;
+
+ mutex_lock(&c->bucket_lock);
+ list_for_each_entry(b, &c->btree_cache, list)
+ ret += 1 << (b->page_order + PAGE_SHIFT);
+
+ mutex_unlock(&c->bucket_lock);
+ return ret;
+ }
+
+ unsigned cache_max_chain(struct cache_set *c)
+ {
+ unsigned ret = 0;
+ struct hlist_head *h;
+
+ mutex_lock(&c->bucket_lock);
+
+ for (h = c->bucket_hash;
+ h < c->bucket_hash + (1 << BUCKET_HASH_BITS);
+ h++) {
+ unsigned i = 0;
+ struct hlist_node *p;
+
+ hlist_for_each(p, h)
+ i++;
+
+ ret = max(ret, i);
+ }
+
+ mutex_unlock(&c->bucket_lock);
+ return ret;
+ }
+
+ unsigned btree_used(struct cache_set *c)
+ {
+ return div64_u64(c->gc_stats.key_bytes * 100,
+ (c->gc_stats.nodes ?: 1) * btree_bytes(c));
+ }
+
+ unsigned average_key_size(struct cache_set *c)
+ {
+ return c->gc_stats.nkeys
+ ? div64_u64(c->gc_stats.data, c->gc_stats.nkeys)
+ : 0;
+ }
+
+ struct cache_set *c = container_of(kobj, struct cache_set, kobj);
+
+ sysfs_print(synchronous, CACHE_SYNC(&c->sb));
+ sysfs_print(journal_delay_ms, c->journal_delay_ms);
+ sysfs_hprint(bucket_size, bucket_bytes(c));
+ sysfs_hprint(block_size, block_bytes(c));
+ sysfs_print(tree_depth, c->root->level);
+ sysfs_print(root_usage_percent, root_usage(c));
+
+ sysfs_hprint(btree_cache_size, cache_size(c));
+ sysfs_print(btree_cache_max_chain, cache_max_chain(c));
+ sysfs_print(cache_available_percent, 100 - c->gc_stats.in_use);
+
+ sysfs_print_time_stats(&c->btree_gc_time, btree_gc, sec, ms);
+ sysfs_print_time_stats(&c->btree_split_time, btree_split, sec, us);
+ sysfs_print_time_stats(&c->sort_time, btree_sort, ms, us);
+ sysfs_print_time_stats(&c->btree_read_time, btree_read, ms, us);
+ sysfs_print_time_stats(&c->try_harder_time, try_harder, ms, us);
+
+ sysfs_print(btree_used_percent, btree_used(c));
+ sysfs_print(btree_nodes, c->gc_stats.nodes);
+ sysfs_hprint(dirty_data, c->gc_stats.dirty);
+ sysfs_hprint(average_key_size, average_key_size(c));
+
+ sysfs_print(cache_read_races,
+ atomic_long_read(&c->cache_read_races));
+
+ sysfs_print(writeback_keys_done,
+ atomic_long_read(&c->writeback_keys_done));
+ sysfs_print(writeback_keys_failed,
+ atomic_long_read(&c->writeback_keys_failed));
+
+ /* See count_io_errors for why 88 */
+ sysfs_print(io_error_halflife, c->error_decay * 88);
+ sysfs_print(io_error_limit, c->error_limit >> IO_ERROR_SHIFT);
+
+ sysfs_hprint(congested,
+ ((uint64_t) bch_get_congested(c)) << 9);
+ sysfs_print(congested_read_threshold_us,
+ c->congested_read_threshold_us);
+ sysfs_print(congested_write_threshold_us,
+ c->congested_write_threshold_us);
+
+ sysfs_print(active_journal_entries, fifo_used(&c->journal.pin));
+ sysfs_printf(verify, "%i", c->verify);
+ sysfs_printf(key_merging_disabled, "%i", c->key_merging_disabled);
+ sysfs_printf(gc_always_rewrite, "%i", c->gc_always_rewrite);
+ sysfs_printf(btree_shrinker_disabled, "%i", c->shrinker_disabled);
+ sysfs_printf(copy_gc_enabled, "%i", c->copy_gc_enabled);
+
+ if (attr == &sysfs_bset_tree_stats)
+ return bch_bset_print_stats(c, buf);
+
+ return 0;
+}
+SHOW_LOCKED(bch_cache_set)
+
+STORE(__bch_cache_set)
+{
+ struct cache_set *c = container_of(kobj, struct cache_set, kobj);
+
+ if (attr == &sysfs_unregister)
+ bch_cache_set_unregister(c);
+
+ if (attr == &sysfs_stop)
+ bch_cache_set_stop(c);
+
+ if (attr == &sysfs_synchronous) {
+ bool sync = strtoul_or_return(buf);
+
+ if (sync != CACHE_SYNC(&c->sb)) {
+ SET_CACHE_SYNC(&c->sb, sync);
+ bcache_write_super(c);
+ }
+ }
+
+ if (attr == &sysfs_flash_vol_create) {
+ int r;
+ uint64_t v;
+ strtoi_h_or_return(buf, v);
+
+ r = bch_flash_dev_create(c, v);
+ if (r)
+ return r;
+ }
+
+ if (attr == &sysfs_clear_stats) {
+ atomic_long_set(&c->writeback_keys_done, 0);
+ atomic_long_set(&c->writeback_keys_failed, 0);
+
+ memset(&c->gc_stats, 0, sizeof(struct gc_stat));
+ bch_cache_accounting_clear(&c->accounting);
+ }
+
+ if (attr == &sysfs_trigger_gc)
+ bch_queue_gc(c);
+
+ if (attr == &sysfs_prune_cache) {
+ struct shrink_control sc;
+ sc.gfp_mask = GFP_KERNEL;
+ sc.nr_to_scan = strtoul_or_return(buf);
+ c->shrink.shrink(&c->shrink, &sc);
+ }
+
+ sysfs_strtoul(congested_read_threshold_us,
+ c->congested_read_threshold_us);
+ sysfs_strtoul(congested_write_threshold_us,
+ c->congested_write_threshold_us);
+
+ if (attr == &sysfs_io_error_limit)
+ c->error_limit = strtoul_or_return(buf) << IO_ERROR_SHIFT;
+
+ /* See count_io_errors() for why 88 */
+ if (attr == &sysfs_io_error_halflife)
+ c->error_decay = strtoul_or_return(buf) / 88;
+
+ sysfs_strtoul(journal_delay_ms, c->journal_delay_ms);
+ sysfs_strtoul(verify, c->verify);
+ sysfs_strtoul(key_merging_disabled, c->key_merging_disabled);
+ sysfs_strtoul(gc_always_rewrite, c->gc_always_rewrite);
+ sysfs_strtoul(btree_shrinker_disabled, c->shrinker_disabled);
+ sysfs_strtoul(copy_gc_enabled, c->copy_gc_enabled);
+
+ return size;
+}
+STORE_LOCKED(bch_cache_set)
+
+SHOW(bch_cache_set_internal)
+{
+ struct cache_set *c = container_of(kobj, struct cache_set, internal);
+ return bch_cache_set_show(&c->kobj, attr, buf);
+}
+
+STORE(bch_cache_set_internal)
+{
+ struct cache_set *c = container_of(kobj, struct cache_set, internal);
+ return bch_cache_set_store(&c->kobj, attr, buf, size);
+}
+
+static void bch_cache_set_internal_release(struct kobject *k)
+{
+}
+
+static struct attribute *bch_cache_set_files[] = {
+ &sysfs_unregister,
+ &sysfs_stop,
+ &sysfs_synchronous,
+ &sysfs_journal_delay_ms,
+ &sysfs_flash_vol_create,
+
+ &sysfs_bucket_size,
+ &sysfs_block_size,
+ &sysfs_tree_depth,
+ &sysfs_root_usage_percent,
+ &sysfs_btree_cache_size,
+ &sysfs_cache_available_percent,
+
+ &sysfs_average_key_size,
+ &sysfs_dirty_data,
+
+ &sysfs_io_error_limit,
+ &sysfs_io_error_halflife,
+ &sysfs_congested,
+ &sysfs_congested_read_threshold_us,
+ &sysfs_congested_write_threshold_us,
+ &sysfs_clear_stats,
+ NULL
+};
+KTYPE(bch_cache_set);
+
+static struct attribute *bch_cache_set_internal_files[] = {
+ &sysfs_active_journal_entries,
+
+ sysfs_time_stats_attribute_list(btree_gc, sec, ms)
+ sysfs_time_stats_attribute_list(btree_split, sec, us)
+ sysfs_time_stats_attribute_list(btree_sort, ms, us)
+ sysfs_time_stats_attribute_list(btree_read, ms, us)
+ sysfs_time_stats_attribute_list(try_harder, ms, us)
+
+ &sysfs_btree_nodes,
+ &sysfs_btree_used_percent,
+ &sysfs_btree_cache_max_chain,
+
+ &sysfs_bset_tree_stats,
+ &sysfs_cache_read_races,
+ &sysfs_writeback_keys_done,
+ &sysfs_writeback_keys_failed,
+
+ &sysfs_trigger_gc,
+ &sysfs_prune_cache,
+#ifdef CONFIG_BCACHE_DEBUG
+ &sysfs_verify,
+ &sysfs_key_merging_disabled,
+#endif
+ &sysfs_gc_always_rewrite,
+ &sysfs_btree_shrinker_disabled,
+ &sysfs_copy_gc_enabled,
+ NULL
+};
+KTYPE(bch_cache_set_internal);
+
+SHOW(__bch_cache)
+{
+ struct cache *ca = container_of(kobj, struct cache, kobj);
+
+ sysfs_hprint(bucket_size, bucket_bytes(ca));
+ sysfs_hprint(block_size, block_bytes(ca));
+ sysfs_print(nbuckets, ca->sb.nbuckets);
+ sysfs_print(discard, ca->discard);
+ sysfs_hprint(written, atomic_long_read(&ca->sectors_written) << 9);
+ sysfs_hprint(btree_written,
+ atomic_long_read(&ca->btree_sectors_written) << 9);
+ sysfs_hprint(metadata_written,
+ (atomic_long_read(&ca->meta_sectors_written) +
+ atomic_long_read(&ca->btree_sectors_written)) << 9);
+
+ sysfs_print(io_errors,
+ atomic_read(&ca->io_errors) >> IO_ERROR_SHIFT);
+
+ sysfs_print(freelist_percent, ca->free.size * 100 /
+ ((size_t) ca->sb.nbuckets));
+
+ if (attr == &sysfs_cache_replacement_policy)
+ return snprint_string_list(buf, PAGE_SIZE,
+ cache_replacement_policies,
+ CACHE_REPLACEMENT(&ca->sb));
+
+ if (attr == &sysfs_priority_stats) {
+ int cmp(const void *l, const void *r)
+ { return *((uint16_t *) r) - *((uint16_t *) l); }
+
+ /* Number of quantiles we compute */
+ const unsigned nq = 31;
+
+ size_t n = ca->sb.nbuckets, i, unused, btree;
+ uint64_t sum = 0;
+ uint16_t q[nq], *p, *cached;
+ ssize_t ret;
+
+ cached = p = vmalloc(ca->sb.nbuckets * sizeof(uint16_t));
+ if (!p)
+ return -ENOMEM;
+
+ mutex_lock(&ca->set->bucket_lock);
+ for (i = ca->sb.first_bucket; i < n; i++)
+ p[i] = ca->buckets[i].prio;
+ mutex_unlock(&ca->set->bucket_lock);
+
+ sort(p, n, sizeof(uint16_t), cmp, NULL);
+
+ while (n &&
+ !cached[n - 1])
+ --n;
+
+ unused = ca->sb.nbuckets - n;
+
+ while (cached < p + n &&
+ *cached == BTREE_PRIO)
+ cached++;
+
+ btree = cached - p;
+ n -= btree;
+
+ for (i = 0; i < n; i++)
+ sum += INITIAL_PRIO - cached[i];
+
+ if (n)
+ do_div(sum, n);
+
+ for (i = 0; i < nq; i++)
+ q[i] = INITIAL_PRIO - cached[n * (i + 1) / (nq + 1)];
+
+ vfree(p);
+
+ ret = snprintf(buf, PAGE_SIZE,
+ "Unused: %zu%%\n"
+ "Metadata: %zu%%\n"
+ "Average: %llu\n"
+ "Sectors per Q: %zu\n"
+ "Quantiles: [",
+ unused * 100 / (size_t) ca->sb.nbuckets,
+ btree * 100 / (size_t) ca->sb.nbuckets, sum,
+ n * ca->sb.bucket_size / (nq + 1));
+
+ for (i = 0; i < nq && ret < (ssize_t) PAGE_SIZE; i++)
+ ret += snprintf(buf + ret, PAGE_SIZE - ret,
+ i < nq - 1 ? "%u " : "%u]\n", q[i]);
+
+ buf[PAGE_SIZE - 1] = '\0';
+ return ret;
+ }
+
+ return 0;
+}
+SHOW_LOCKED(bch_cache)
+
+STORE(__bch_cache)
+{
+ struct cache *ca = container_of(kobj, struct cache, kobj);
+
+ if (attr == &sysfs_discard) {
+ bool v = strtoul_or_return(buf);
+
+ if (blk_queue_discard(bdev_get_queue(ca->bdev)))
+ ca->discard = v;
+
+ if (v != CACHE_DISCARD(&ca->sb)) {
+ SET_CACHE_DISCARD(&ca->sb, v);
+ bcache_write_super(ca->set);
+ }
+ }
+
+ if (attr == &sysfs_cache_replacement_policy) {
+ ssize_t v = read_string_list(buf, cache_replacement_policies);
+
+ if (v < 0)
+ return v;
+
+ if ((unsigned) v != CACHE_REPLACEMENT(&ca->sb)) {
+ mutex_lock(&ca->set->bucket_lock);
+ SET_CACHE_REPLACEMENT(&ca->sb, v);
+ mutex_unlock(&ca->set->bucket_lock);
+
+ bcache_write_super(ca->set);
+ }
+ }
+
+ if (attr == &sysfs_freelist_percent) {
+ DECLARE_FIFO(long, free);
+ long i;
+ size_t p = strtoul_or_return(buf);
+
+ p = clamp_t(size_t,
+ ((size_t) ca->sb.nbuckets * p) / 100,
+ roundup_pow_of_two(ca->sb.nbuckets) >> 9,
+ ca->sb.nbuckets / 2);
+
+ if (!init_fifo_exact(&free, p, GFP_KERNEL))
+ return -ENOMEM;
+
+ mutex_lock(&ca->set->bucket_lock);
+
+ fifo_move(&free, &ca->free);
+ fifo_swap(&free, &ca->free);
+
+ mutex_unlock(&ca->set->bucket_lock);
+
+ while (fifo_pop(&free, i))
+ atomic_dec(&ca->buckets[i].pin);
+
+ free_fifo(&free);
+ }
+
+ if (attr == &sysfs_clear_stats) {
+ atomic_long_set(&ca->sectors_written, 0);
+ atomic_long_set(&ca->btree_sectors_written, 0);
+ atomic_long_set(&ca->meta_sectors_written, 0);
+ atomic_set(&ca->io_count, 0);
+ atomic_set(&ca->io_errors, 0);
+ }
+
+ return size;
+}
+STORE_LOCKED(bch_cache)
+
+static struct attribute *bch_cache_files[] = {
+ &sysfs_bucket_size,
+ &sysfs_block_size,
+ &sysfs_nbuckets,
+ &sysfs_priority_stats,
+ &sysfs_discard,
+ &sysfs_written,
+ &sysfs_btree_written,
+ &sysfs_metadata_written,
+ &sysfs_io_errors,
+ &sysfs_clear_stats,
+ &sysfs_freelist_percent,
+ &sysfs_cache_replacement_policy,
+ NULL
+};
+KTYPE(bch_cache);
--- /dev/null
+#ifndef _BCACHE_SYSFS_H_
+#define _BCACHE_SYSFS_H_
+
+#define KTYPE(type) \
+struct kobj_type type ## _ktype = { \
+ .release = type ## _release, \
+ .sysfs_ops = &((const struct sysfs_ops) { \
+ .show = type ## _show, \
+ .store = type ## _store \
+ }), \
+ .default_attrs = type ## _files \
+}
+
+#define SHOW(fn) \
+static ssize_t fn ## _show(struct kobject *kobj, struct attribute *attr,\
+ char *buf) \
+
+#define STORE(fn) \
+static ssize_t fn ## _store(struct kobject *kobj, struct attribute *attr,\
+ const char *buf, size_t size) \
+
+#define SHOW_LOCKED(fn) \
+SHOW(fn) \
+{ \
+ ssize_t ret; \
+ mutex_lock(&bch_register_lock); \
+ ret = __ ## fn ## _show(kobj, attr, buf); \
+ mutex_unlock(&bch_register_lock); \
+ return ret; \
+}
+
+#define STORE_LOCKED(fn) \
+STORE(fn) \
+{ \
+ ssize_t ret; \
+ mutex_lock(&bch_register_lock); \
+ ret = __ ## fn ## _store(kobj, attr, buf, size); \
+ mutex_unlock(&bch_register_lock); \
+ return ret; \
+}
+
+#define __sysfs_attribute(_name, _mode) \
+ static struct attribute sysfs_##_name = \
+ { .name = #_name, .mode = _mode }
+
+#define write_attribute(n) __sysfs_attribute(n, S_IWUSR)
+#define read_attribute(n) __sysfs_attribute(n, S_IRUGO)
+#define rw_attribute(n) __sysfs_attribute(n, S_IRUGO|S_IWUSR)
+
+#define sysfs_printf(file, fmt, ...) \
+do { \
+ if (attr == &sysfs_ ## file) \
+ return snprintf(buf, PAGE_SIZE, fmt "\n", __VA_ARGS__); \
+} while (0)
+
+#define sysfs_print(file, var) \
+do { \
+ if (attr == &sysfs_ ## file) \
+ return snprint(buf, PAGE_SIZE, var); \
+} while (0)
+
+#define sysfs_hprint(file, val) \
+do { \
+ if (attr == &sysfs_ ## file) { \
+ ssize_t ret = hprint(buf, val); \
+ strcat(buf, "\n"); \
+ return ret + 1; \
+ } \
+} while (0)
+
+#define var_printf(_var, fmt) sysfs_printf(_var, fmt, var(_var))
+#define var_print(_var) sysfs_print(_var, var(_var))
+#define var_hprint(_var) sysfs_hprint(_var, var(_var))
+
+#define sysfs_strtoul(file, var) \
+do { \
+ if (attr == &sysfs_ ## file) \
+ return strtoul_safe(buf, var) ?: (ssize_t) size; \
+} while (0)
+
+#define sysfs_strtoul_clamp(file, var, min, max) \
+do { \
+ if (attr == &sysfs_ ## file) \
+ return strtoul_safe_clamp(buf, var, min, max) \
+ ?: (ssize_t) size; \
+} while (0)
+
+#define strtoul_or_return(cp) \
+({ \
+ unsigned long _v; \
+ int _r = kstrtoul(cp, 10, &_v); \
+ if (_r) \
+ return _r; \
+ _v; \
+})
+
+#define strtoi_h_or_return(cp, v) \
+do { \
+ int _r = strtoi_h(cp, &v); \
+ if (_r) \
+ return _r; \
+} while (0)
+
+#define sysfs_hatoi(file, var) \
+do { \
+ if (attr == &sysfs_ ## file) \
+ return strtoi_h(buf, &var) ?: (ssize_t) size; \
+} while (0)
+
+#endif /* _BCACHE_SYSFS_H_ */
--- /dev/null
+#include "bcache.h"
+#include "btree.h"
+#include "request.h"
+
+#include <linux/module.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/bcache.h>
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_request_start);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_request_end);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_passthrough);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_cache_hit);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_cache_miss);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_read_retry);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_writethrough);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_writeback);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_write_skip);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_btree_read);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_btree_write);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_write_dirty);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_read_dirty);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_journal_write);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_cache_insert);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_gc_start);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_gc_end);
--- /dev/null
+/*
+ * random utiility code, for bcache but in theory not specific to bcache
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/types.h>
+
+#include "util.h"
+
+#define simple_strtoint(c, end, base) simple_strtol(c, end, base)
+#define simple_strtouint(c, end, base) simple_strtoul(c, end, base)
+
+#define STRTO_H(name, type) \
+int name ## _h(const char *cp, type *res) \
+{ \
+ int u = 0; \
+ char *e; \
+ type i = simple_ ## name(cp, &e, 10); \
+ \
+ switch (tolower(*e)) { \
+ default: \
+ return -EINVAL; \
+ case 'y': \
+ case 'z': \
+ u++; \
+ case 'e': \
+ u++; \
+ case 'p': \
+ u++; \
+ case 't': \
+ u++; \
+ case 'g': \
+ u++; \
+ case 'm': \
+ u++; \
+ case 'k': \
+ u++; \
+ if (e++ == cp) \
+ return -EINVAL; \
+ case '\n': \
+ case '\0': \
+ if (*e == '\n') \
+ e++; \
+ } \
+ \
+ if (*e) \
+ return -EINVAL; \
+ \
+ while (u--) { \
+ if ((type) ~0 > 0 && \
+ (type) ~0 / 1024 <= i) \
+ return -EINVAL; \
+ if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) || \
+ (i < 0 && -ANYSINT_MAX(type) / 1024 > i)) \
+ return -EINVAL; \
+ i *= 1024; \
+ } \
+ \
+ *res = i; \
+ return 0; \
+} \
+EXPORT_SYMBOL_GPL(name ## _h);
+
+STRTO_H(strtoint, int)
+STRTO_H(strtouint, unsigned int)
+STRTO_H(strtoll, long long)
+STRTO_H(strtoull, unsigned long long)
+
+ssize_t hprint(char *buf, int64_t v)
+{
+ static const char units[] = "?kMGTPEZY";
+ char dec[3] = "";
+ int u, t = 0;
+
+ for (u = 0; v >= 1024 || v <= -1024; u++) {
+ t = v & ~(~0 << 10);
+ v >>= 10;
+ }
+
+ if (!u)
+ return sprintf(buf, "%llu", v);
+
+ if (v < 100 && v > -100)
+ sprintf(dec, ".%i", t / 100);
+
+ return sprintf(buf, "%lli%s%c", v, dec, units[u]);
+}
+EXPORT_SYMBOL_GPL(hprint);
+
+ssize_t snprint_string_list(char *buf, size_t size, const char * const list[],
+ size_t selected)
+{
+ char *out = buf;
+ size_t i;
+
+ for (i = 0; list[i]; i++)
+ out += snprintf(out, buf + size - out,
+ i == selected ? "[%s] " : "%s ", list[i]);
+
+ out[-1] = '\n';
+ return out - buf;
+}
+EXPORT_SYMBOL_GPL(snprint_string_list);
+
+ssize_t read_string_list(const char *buf, const char * const list[])
+{
+ size_t i;
+ char *s, *d = kstrndup(buf, PAGE_SIZE - 1, GFP_KERNEL);
+ if (!d)
+ return -ENOMEM;
+
+ s = strim(d);
+
+ for (i = 0; list[i]; i++)
+ if (!strcmp(list[i], s))
+ break;
+
+ kfree(d);
+
+ if (!list[i])
+ return -EINVAL;
+
+ return i;
+}
+EXPORT_SYMBOL_GPL(read_string_list);
+
+bool is_zero(const char *p, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++)
+ if (p[i])
+ return false;
+ return true;
+}
+EXPORT_SYMBOL_GPL(is_zero);
+
+int parse_uuid(const char *s, char *uuid)
+{
+ size_t i, j, x;
+ memset(uuid, 0, 16);
+
+ for (i = 0, j = 0;
+ i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
+ i++) {
+ x = s[i] | 32;
+
+ switch (x) {
+ case '0'...'9':
+ x -= '0';
+ break;
+ case 'a'...'f':
+ x -= 'a' - 10;
+ break;
+ default:
+ continue;
+ }
+
+ if (!(j & 1))
+ x <<= 4;
+ uuid[j++ >> 1] |= x;
+ }
+ return i;
+}
+EXPORT_SYMBOL_GPL(parse_uuid);
+
+void time_stats_update(struct time_stats *stats, uint64_t start_time)
+{
+ uint64_t now = local_clock();
+ uint64_t duration = time_after64(now, start_time)
+ ? now - start_time : 0;
+ uint64_t last = time_after64(now, stats->last)
+ ? now - stats->last : 0;
+
+ stats->max_duration = max(stats->max_duration, duration);
+
+ if (stats->last) {
+ ewma_add(stats->average_duration, duration, 8, 8);
+
+ if (stats->average_frequency)
+ ewma_add(stats->average_frequency, last, 8, 8);
+ else
+ stats->average_frequency = last << 8;
+ } else {
+ stats->average_duration = duration << 8;
+ }
+
+ stats->last = now ?: 1;
+}
+EXPORT_SYMBOL_GPL(time_stats_update);
+
+unsigned next_delay(struct ratelimit *d, uint64_t done)
+{
+ uint64_t now = local_clock();
+
+ d->next += div_u64(done, d->rate);
+
+ return time_after64(d->next, now)
+ ? div_u64(d->next - now, NSEC_PER_SEC / HZ)
+ : 0;
+}
+EXPORT_SYMBOL_GPL(next_delay);
+
+void bio_map(struct bio *bio, void *base)
+{
+ size_t size = bio->bi_size;
+ struct bio_vec *bv = bio->bi_io_vec;
+
+ BUG_ON(!bio->bi_size);
+ BUG_ON(bio->bi_vcnt);
+
+ bv->bv_offset = base ? ((unsigned long) base) % PAGE_SIZE : 0;
+ goto start;
+
+ for (; size; bio->bi_vcnt++, bv++) {
+ bv->bv_offset = 0;
+start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset,
+ size);
+ if (base) {
+ bv->bv_page = is_vmalloc_addr(base)
+ ? vmalloc_to_page(base)
+ : virt_to_page(base);
+
+ base += bv->bv_len;
+ }
+
+ size -= bv->bv_len;
+ }
+}
+EXPORT_SYMBOL_GPL(bio_map);
+
+int bio_alloc_pages(struct bio *bio, gfp_t gfp)
+{
+ int i;
+ struct bio_vec *bv;
+
+ bio_for_each_segment(bv, bio, i) {
+ bv->bv_page = alloc_page(gfp);
+ if (!bv->bv_page) {
+ while (bv-- != bio->bi_io_vec + bio->bi_idx)
+ __free_page(bv->bv_page);
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(bio_alloc_pages);
+
+/*
+ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group (Any
+ * use permitted, subject to terms of PostgreSQL license; see.)
+
+ * If we have a 64-bit integer type, then a 64-bit CRC looks just like the
+ * usual sort of implementation. (See Ross Williams' excellent introduction
+ * A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS, available from
+ * ftp://ftp.rocksoft.com/papers/crc_v3.txt or several other net sites.)
+ * If we have no working 64-bit type, then fake it with two 32-bit registers.
+ *
+ * The present implementation is a normal (not "reflected", in Williams'
+ * terms) 64-bit CRC, using initial all-ones register contents and a final
+ * bit inversion. The chosen polynomial is borrowed from the DLT1 spec
+ * (ECMA-182, available from http://www.ecma.ch/ecma1/STAND/ECMA-182.HTM):
+ *
+ * x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 +
+ * x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 +
+ * x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
+ * x^7 + x^4 + x + 1
+*/
+
+static const uint64_t crc_table[256] = {
+ 0x0000000000000000, 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26,
+ 0xC711223CFA3E5BB5, 0x493366450E42ECDF, 0x0BC387AEA7A8DA4C,
+ 0xCCD2A5925D9681F9, 0x8E224479F47CB76A, 0x9266CC8A1C85D9BE,
+ 0xD0962D61B56FEF2D, 0x17870F5D4F51B498, 0x5577EEB6E6BB820B,
+ 0xDB55AACF12C73561, 0x99A54B24BB2D03F2, 0x5EB4691841135847,
+ 0x1C4488F3E8F96ED4, 0x663D78FF90E185EF, 0x24CD9914390BB37C,
+ 0xE3DCBB28C335E8C9, 0xA12C5AC36ADFDE5A, 0x2F0E1EBA9EA36930,
+ 0x6DFEFF5137495FA3, 0xAAEFDD6DCD770416, 0xE81F3C86649D3285,
+ 0xF45BB4758C645C51, 0xB6AB559E258E6AC2, 0x71BA77A2DFB03177,
+ 0x334A9649765A07E4, 0xBD68D2308226B08E, 0xFF9833DB2BCC861D,
+ 0x388911E7D1F2DDA8, 0x7A79F00C7818EB3B, 0xCC7AF1FF21C30BDE,
+ 0x8E8A101488293D4D, 0x499B3228721766F8, 0x0B6BD3C3DBFD506B,
+ 0x854997BA2F81E701, 0xC7B97651866BD192, 0x00A8546D7C558A27,
+ 0x4258B586D5BFBCB4, 0x5E1C3D753D46D260, 0x1CECDC9E94ACE4F3,
+ 0xDBFDFEA26E92BF46, 0x990D1F49C77889D5, 0x172F5B3033043EBF,
+ 0x55DFBADB9AEE082C, 0x92CE98E760D05399, 0xD03E790CC93A650A,
+ 0xAA478900B1228E31, 0xE8B768EB18C8B8A2, 0x2FA64AD7E2F6E317,
+ 0x6D56AB3C4B1CD584, 0xE374EF45BF6062EE, 0xA1840EAE168A547D,
+ 0x66952C92ECB40FC8, 0x2465CD79455E395B, 0x3821458AADA7578F,
+ 0x7AD1A461044D611C, 0xBDC0865DFE733AA9, 0xFF3067B657990C3A,
+ 0x711223CFA3E5BB50, 0x33E2C2240A0F8DC3, 0xF4F3E018F031D676,
+ 0xB60301F359DBE0E5, 0xDA050215EA6C212F, 0x98F5E3FE438617BC,
+ 0x5FE4C1C2B9B84C09, 0x1D14202910527A9A, 0x93366450E42ECDF0,
+ 0xD1C685BB4DC4FB63, 0x16D7A787B7FAA0D6, 0x5427466C1E109645,
+ 0x4863CE9FF6E9F891, 0x0A932F745F03CE02, 0xCD820D48A53D95B7,
+ 0x8F72ECA30CD7A324, 0x0150A8DAF8AB144E, 0x43A04931514122DD,
+ 0x84B16B0DAB7F7968, 0xC6418AE602954FFB, 0xBC387AEA7A8DA4C0,
+ 0xFEC89B01D3679253, 0x39D9B93D2959C9E6, 0x7B2958D680B3FF75,
+ 0xF50B1CAF74CF481F, 0xB7FBFD44DD257E8C, 0x70EADF78271B2539,
+ 0x321A3E938EF113AA, 0x2E5EB66066087D7E, 0x6CAE578BCFE24BED,
+ 0xABBF75B735DC1058, 0xE94F945C9C3626CB, 0x676DD025684A91A1,
+ 0x259D31CEC1A0A732, 0xE28C13F23B9EFC87, 0xA07CF2199274CA14,
+ 0x167FF3EACBAF2AF1, 0x548F120162451C62, 0x939E303D987B47D7,
+ 0xD16ED1D631917144, 0x5F4C95AFC5EDC62E, 0x1DBC74446C07F0BD,
+ 0xDAAD56789639AB08, 0x985DB7933FD39D9B, 0x84193F60D72AF34F,
+ 0xC6E9DE8B7EC0C5DC, 0x01F8FCB784FE9E69, 0x43081D5C2D14A8FA,
+ 0xCD2A5925D9681F90, 0x8FDAB8CE70822903, 0x48CB9AF28ABC72B6,
+ 0x0A3B7B1923564425, 0x70428B155B4EAF1E, 0x32B26AFEF2A4998D,
+ 0xF5A348C2089AC238, 0xB753A929A170F4AB, 0x3971ED50550C43C1,
+ 0x7B810CBBFCE67552, 0xBC902E8706D82EE7, 0xFE60CF6CAF321874,
+ 0xE224479F47CB76A0, 0xA0D4A674EE214033, 0x67C58448141F1B86,
+ 0x253565A3BDF52D15, 0xAB1721DA49899A7F, 0xE9E7C031E063ACEC,
+ 0x2EF6E20D1A5DF759, 0x6C0603E6B3B7C1CA, 0xF6FAE5C07D3274CD,
+ 0xB40A042BD4D8425E, 0x731B26172EE619EB, 0x31EBC7FC870C2F78,
+ 0xBFC9838573709812, 0xFD39626EDA9AAE81, 0x3A28405220A4F534,
+ 0x78D8A1B9894EC3A7, 0x649C294A61B7AD73, 0x266CC8A1C85D9BE0,
+ 0xE17DEA9D3263C055, 0xA38D0B769B89F6C6, 0x2DAF4F0F6FF541AC,
+ 0x6F5FAEE4C61F773F, 0xA84E8CD83C212C8A, 0xEABE6D3395CB1A19,
+ 0x90C79D3FEDD3F122, 0xD2377CD44439C7B1, 0x15265EE8BE079C04,
+ 0x57D6BF0317EDAA97, 0xD9F4FB7AE3911DFD, 0x9B041A914A7B2B6E,
+ 0x5C1538ADB04570DB, 0x1EE5D94619AF4648, 0x02A151B5F156289C,
+ 0x4051B05E58BC1E0F, 0x87409262A28245BA, 0xC5B073890B687329,
+ 0x4B9237F0FF14C443, 0x0962D61B56FEF2D0, 0xCE73F427ACC0A965,
+ 0x8C8315CC052A9FF6, 0x3A80143F5CF17F13, 0x7870F5D4F51B4980,
+ 0xBF61D7E80F251235, 0xFD913603A6CF24A6, 0x73B3727A52B393CC,
+ 0x31439391FB59A55F, 0xF652B1AD0167FEEA, 0xB4A25046A88DC879,
+ 0xA8E6D8B54074A6AD, 0xEA16395EE99E903E, 0x2D071B6213A0CB8B,
+ 0x6FF7FA89BA4AFD18, 0xE1D5BEF04E364A72, 0xA3255F1BE7DC7CE1,
+ 0x64347D271DE22754, 0x26C49CCCB40811C7, 0x5CBD6CC0CC10FAFC,
+ 0x1E4D8D2B65FACC6F, 0xD95CAF179FC497DA, 0x9BAC4EFC362EA149,
+ 0x158E0A85C2521623, 0x577EEB6E6BB820B0, 0x906FC95291867B05,
+ 0xD29F28B9386C4D96, 0xCEDBA04AD0952342, 0x8C2B41A1797F15D1,
+ 0x4B3A639D83414E64, 0x09CA82762AAB78F7, 0x87E8C60FDED7CF9D,
+ 0xC51827E4773DF90E, 0x020905D88D03A2BB, 0x40F9E43324E99428,
+ 0x2CFFE7D5975E55E2, 0x6E0F063E3EB46371, 0xA91E2402C48A38C4,
+ 0xEBEEC5E96D600E57, 0x65CC8190991CB93D, 0x273C607B30F68FAE,
+ 0xE02D4247CAC8D41B, 0xA2DDA3AC6322E288, 0xBE992B5F8BDB8C5C,
+ 0xFC69CAB42231BACF, 0x3B78E888D80FE17A, 0x7988096371E5D7E9,
+ 0xF7AA4D1A85996083, 0xB55AACF12C735610, 0x724B8ECDD64D0DA5,
+ 0x30BB6F267FA73B36, 0x4AC29F2A07BFD00D, 0x08327EC1AE55E69E,
+ 0xCF235CFD546BBD2B, 0x8DD3BD16FD818BB8, 0x03F1F96F09FD3CD2,
+ 0x41011884A0170A41, 0x86103AB85A2951F4, 0xC4E0DB53F3C36767,
+ 0xD8A453A01B3A09B3, 0x9A54B24BB2D03F20, 0x5D45907748EE6495,
+ 0x1FB5719CE1045206, 0x919735E51578E56C, 0xD367D40EBC92D3FF,
+ 0x1476F63246AC884A, 0x568617D9EF46BED9, 0xE085162AB69D5E3C,
+ 0xA275F7C11F7768AF, 0x6564D5FDE549331A, 0x279434164CA30589,
+ 0xA9B6706FB8DFB2E3, 0xEB46918411358470, 0x2C57B3B8EB0BDFC5,
+ 0x6EA7525342E1E956, 0x72E3DAA0AA188782, 0x30133B4B03F2B111,
+ 0xF7021977F9CCEAA4, 0xB5F2F89C5026DC37, 0x3BD0BCE5A45A6B5D,
+ 0x79205D0E0DB05DCE, 0xBE317F32F78E067B, 0xFCC19ED95E6430E8,
+ 0x86B86ED5267CDBD3, 0xC4488F3E8F96ED40, 0x0359AD0275A8B6F5,
+ 0x41A94CE9DC428066, 0xCF8B0890283E370C, 0x8D7BE97B81D4019F,
+ 0x4A6ACB477BEA5A2A, 0x089A2AACD2006CB9, 0x14DEA25F3AF9026D,
+ 0x562E43B4931334FE, 0x913F6188692D6F4B, 0xD3CF8063C0C759D8,
+ 0x5DEDC41A34BBEEB2, 0x1F1D25F19D51D821, 0xD80C07CD676F8394,
+ 0x9AFCE626CE85B507
+};
+
+uint64_t crc64_update(uint64_t crc, const void *_data, size_t len)
+{
+ const unsigned char *data = _data;
+
+ while (len--) {
+ int i = ((int) (crc >> 56) ^ *data++) & 0xFF;
+ crc = crc_table[i] ^ (crc << 8);
+ }
+
+ return crc;
+}
+EXPORT_SYMBOL(crc64_update);
+
+uint64_t crc64(const void *data, size_t len)
+{
+ uint64_t crc = 0xffffffffffffffff;
+
+ crc = crc64_update(crc, data, len);
+
+ return crc ^ 0xffffffffffffffff;
+}
+EXPORT_SYMBOL(crc64);
--- /dev/null
+
+#ifndef _BCACHE_UTIL_H
+#define _BCACHE_UTIL_H
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/llist.h>
+#include <linux/ratelimit.h>
+#include <linux/vmalloc.h>
+#include <linux/workqueue.h>
+
+#include "closure.h"
+
+#define PAGE_SECTORS (PAGE_SIZE / 512)
+
+struct closure;
+
+#include <trace/events/bcache.h>
+
+#ifdef CONFIG_BCACHE_EDEBUG
+
+#define atomic_dec_bug(v) BUG_ON(atomic_dec_return(v) < 0)
+#define atomic_inc_bug(v, i) BUG_ON(atomic_inc_return(v) <= i)
+
+#else /* EDEBUG */
+
+#define atomic_dec_bug(v) atomic_dec(v)
+#define atomic_inc_bug(v, i) atomic_inc(v)
+
+#endif
+
+#define BITMASK(name, type, field, offset, size) \
+static inline uint64_t name(const type *k) \
+{ return (k->field >> offset) & ~(((uint64_t) ~0) << size); } \
+ \
+static inline void SET_##name(type *k, uint64_t v) \
+{ \
+ k->field &= ~(~((uint64_t) ~0 << size) << offset); \
+ k->field |= v << offset; \
+}
+
+#define DECLARE_HEAP(type, name) \
+ struct { \
+ size_t size, used; \
+ type *data; \
+ } name
+
+#define init_heap(heap, _size, gfp) \
+({ \
+ size_t _bytes; \
+ (heap)->used = 0; \
+ (heap)->size = (_size); \
+ _bytes = (heap)->size * sizeof(*(heap)->data); \
+ (heap)->data = NULL; \
+ if (_bytes < KMALLOC_MAX_SIZE) \
+ (heap)->data = kmalloc(_bytes, (gfp)); \
+ if ((!(heap)->data) && ((gfp) & GFP_KERNEL)) \
+ (heap)->data = vmalloc(_bytes); \
+ (heap)->data; \
+})
+
+#define free_heap(heap) \
+do { \
+ if (is_vmalloc_addr((heap)->data)) \
+ vfree((heap)->data); \
+ else \
+ kfree((heap)->data); \
+ (heap)->data = NULL; \
+} while (0)
+
+#define heap_swap(h, i, j) swap((h)->data[i], (h)->data[j])
+
+#define heap_sift(h, i, cmp) \
+do { \
+ size_t _r, _j = i; \
+ \
+ for (; _j * 2 + 1 < (h)->used; _j = _r) { \
+ _r = _j * 2 + 1; \
+ if (_r + 1 < (h)->used && \
+ cmp((h)->data[_r], (h)->data[_r + 1])) \
+ _r++; \
+ \
+ if (cmp((h)->data[_r], (h)->data[_j])) \
+ break; \
+ heap_swap(h, _r, _j); \
+ } \
+} while (0)
+
+#define heap_sift_down(h, i, cmp) \
+do { \
+ while (i) { \
+ size_t p = (i - 1) / 2; \
+ if (cmp((h)->data[i], (h)->data[p])) \
+ break; \
+ heap_swap(h, i, p); \
+ i = p; \
+ } \
+} while (0)
+
+#define heap_add(h, d, cmp) \
+({ \
+ bool _r = !heap_full(h); \
+ if (_r) { \
+ size_t _i = (h)->used++; \
+ (h)->data[_i] = d; \
+ \
+ heap_sift_down(h, _i, cmp); \
+ heap_sift(h, _i, cmp); \
+ } \
+ _r; \
+})
+
+#define heap_pop(h, d, cmp) \
+({ \
+ bool _r = (h)->used; \
+ if (_r) { \
+ (d) = (h)->data[0]; \
+ (h)->used--; \
+ heap_swap(h, 0, (h)->used); \
+ heap_sift(h, 0, cmp); \
+ } \
+ _r; \
+})
+
+#define heap_peek(h) ((h)->size ? (h)->data[0] : NULL)
+
+#define heap_full(h) ((h)->used == (h)->size)
+
+#define DECLARE_FIFO(type, name) \
+ struct { \
+ size_t front, back, size, mask; \
+ type *data; \
+ } name
+
+#define fifo_for_each(c, fifo, iter) \
+ for (iter = (fifo)->front; \
+ c = (fifo)->data[iter], iter != (fifo)->back; \
+ iter = (iter + 1) & (fifo)->mask)
+
+#define __init_fifo(fifo, gfp) \
+({ \
+ size_t _allocated_size, _bytes; \
+ BUG_ON(!(fifo)->size); \
+ \
+ _allocated_size = roundup_pow_of_two((fifo)->size + 1); \
+ _bytes = _allocated_size * sizeof(*(fifo)->data); \
+ \
+ (fifo)->mask = _allocated_size - 1; \
+ (fifo)->front = (fifo)->back = 0; \
+ (fifo)->data = NULL; \
+ \
+ if (_bytes < KMALLOC_MAX_SIZE) \
+ (fifo)->data = kmalloc(_bytes, (gfp)); \
+ if ((!(fifo)->data) && ((gfp) & GFP_KERNEL)) \
+ (fifo)->data = vmalloc(_bytes); \
+ (fifo)->data; \
+})
+
+#define init_fifo_exact(fifo, _size, gfp) \
+({ \
+ (fifo)->size = (_size); \
+ __init_fifo(fifo, gfp); \
+})
+
+#define init_fifo(fifo, _size, gfp) \
+({ \
+ (fifo)->size = (_size); \
+ if ((fifo)->size > 4) \
+ (fifo)->size = roundup_pow_of_two((fifo)->size) - 1; \
+ __init_fifo(fifo, gfp); \
+})
+
+#define free_fifo(fifo) \
+do { \
+ if (is_vmalloc_addr((fifo)->data)) \
+ vfree((fifo)->data); \
+ else \
+ kfree((fifo)->data); \
+ (fifo)->data = NULL; \
+} while (0)
+
+#define fifo_used(fifo) (((fifo)->back - (fifo)->front) & (fifo)->mask)
+#define fifo_free(fifo) ((fifo)->size - fifo_used(fifo))
+
+#define fifo_empty(fifo) (!fifo_used(fifo))
+#define fifo_full(fifo) (!fifo_free(fifo))
+
+#define fifo_front(fifo) ((fifo)->data[(fifo)->front])
+#define fifo_back(fifo) \
+ ((fifo)->data[((fifo)->back - 1) & (fifo)->mask])
+
+#define fifo_idx(fifo, p) (((p) - &fifo_front(fifo)) & (fifo)->mask)
+
+#define fifo_push_back(fifo, i) \
+({ \
+ bool _r = !fifo_full((fifo)); \
+ if (_r) { \
+ (fifo)->data[(fifo)->back++] = (i); \
+ (fifo)->back &= (fifo)->mask; \
+ } \
+ _r; \
+})
+
+#define fifo_pop_front(fifo, i) \
+({ \
+ bool _r = !fifo_empty((fifo)); \
+ if (_r) { \
+ (i) = (fifo)->data[(fifo)->front++]; \
+ (fifo)->front &= (fifo)->mask; \
+ } \
+ _r; \
+})
+
+#define fifo_push_front(fifo, i) \
+({ \
+ bool _r = !fifo_full((fifo)); \
+ if (_r) { \
+ --(fifo)->front; \
+ (fifo)->front &= (fifo)->mask; \
+ (fifo)->data[(fifo)->front] = (i); \
+ } \
+ _r; \
+})
+
+#define fifo_pop_back(fifo, i) \
+({ \
+ bool _r = !fifo_empty((fifo)); \
+ if (_r) { \
+ --(fifo)->back; \
+ (fifo)->back &= (fifo)->mask; \
+ (i) = (fifo)->data[(fifo)->back] \
+ } \
+ _r; \
+})
+
+#define fifo_push(fifo, i) fifo_push_back(fifo, (i))
+#define fifo_pop(fifo, i) fifo_pop_front(fifo, (i))
+
+#define fifo_swap(l, r) \
+do { \
+ swap((l)->front, (r)->front); \
+ swap((l)->back, (r)->back); \
+ swap((l)->size, (r)->size); \
+ swap((l)->mask, (r)->mask); \
+ swap((l)->data, (r)->data); \
+} while (0)
+
+#define fifo_move(dest, src) \
+do { \
+ typeof(*((dest)->data)) _t; \
+ while (!fifo_full(dest) && \
+ fifo_pop(src, _t)) \
+ fifo_push(dest, _t); \
+} while (0)
+
+/*
+ * Simple array based allocator - preallocates a number of elements and you can
+ * never allocate more than that, also has no locking.
+ *
+ * Handy because if you know you only need a fixed number of elements you don't
+ * have to worry about memory allocation failure, and sometimes a mempool isn't
+ * what you want.
+ *
+ * We treat the free elements as entries in a singly linked list, and the
+ * freelist as a stack - allocating and freeing push and pop off the freelist.
+ */
+
+#define DECLARE_ARRAY_ALLOCATOR(type, name, size) \
+ struct { \
+ type *freelist; \
+ type data[size]; \
+ } name
+
+#define array_alloc(array) \
+({ \
+ typeof((array)->freelist) _ret = (array)->freelist; \
+ \
+ if (_ret) \
+ (array)->freelist = *((typeof((array)->freelist) *) _ret);\
+ \
+ _ret; \
+})
+
+#define array_free(array, ptr) \
+do { \
+ typeof((array)->freelist) _ptr = ptr; \
+ \
+ *((typeof((array)->freelist) *) _ptr) = (array)->freelist; \
+ (array)->freelist = _ptr; \
+} while (0)
+
+#define array_allocator_init(array) \
+do { \
+ typeof((array)->freelist) _i; \
+ \
+ BUILD_BUG_ON(sizeof((array)->data[0]) < sizeof(void *)); \
+ (array)->freelist = NULL; \
+ \
+ for (_i = (array)->data; \
+ _i < (array)->data + ARRAY_SIZE((array)->data); \
+ _i++) \
+ array_free(array, _i); \
+} while (0)
+
+#define array_freelist_empty(array) ((array)->freelist == NULL)
+
+#define ANYSINT_MAX(t) \
+ ((((t) 1 << (sizeof(t) * 8 - 2)) - (t) 1) * (t) 2 + (t) 1)
+
+int strtoint_h(const char *, int *);
+int strtouint_h(const char *, unsigned int *);
+int strtoll_h(const char *, long long *);
+int strtoull_h(const char *, unsigned long long *);
+
+static inline int strtol_h(const char *cp, long *res)
+{
+#if BITS_PER_LONG == 32
+ return strtoint_h(cp, (int *) res);
+#else
+ return strtoll_h(cp, (long long *) res);
+#endif
+}
+
+static inline int strtoul_h(const char *cp, long *res)
+{
+#if BITS_PER_LONG == 32
+ return strtouint_h(cp, (unsigned int *) res);
+#else
+ return strtoull_h(cp, (unsigned long long *) res);
+#endif
+}
+
+#define strtoi_h(cp, res) \
+ (__builtin_types_compatible_p(typeof(*res), int) \
+ ? strtoint_h(cp, (void *) res) \
+ : __builtin_types_compatible_p(typeof(*res), long) \
+ ? strtol_h(cp, (void *) res) \
+ : __builtin_types_compatible_p(typeof(*res), long long) \
+ ? strtoll_h(cp, (void *) res) \
+ : __builtin_types_compatible_p(typeof(*res), unsigned int) \
+ ? strtouint_h(cp, (void *) res) \
+ : __builtin_types_compatible_p(typeof(*res), unsigned long) \
+ ? strtoul_h(cp, (void *) res) \
+ : __builtin_types_compatible_p(typeof(*res), unsigned long long)\
+ ? strtoull_h(cp, (void *) res) : -EINVAL)
+
+#define strtoul_safe(cp, var) \
+({ \
+ unsigned long _v; \
+ int _r = kstrtoul(cp, 10, &_v); \
+ if (!_r) \
+ var = _v; \
+ _r; \
+})
+
+#define strtoul_safe_clamp(cp, var, min, max) \
+({ \
+ unsigned long _v; \
+ int _r = kstrtoul(cp, 10, &_v); \
+ if (!_r) \
+ var = clamp_t(typeof(var), _v, min, max); \
+ _r; \
+})
+
+#define snprint(buf, size, var) \
+ snprintf(buf, size, \
+ __builtin_types_compatible_p(typeof(var), int) \
+ ? "%i\n" : \
+ __builtin_types_compatible_p(typeof(var), unsigned) \
+ ? "%u\n" : \
+ __builtin_types_compatible_p(typeof(var), long) \
+ ? "%li\n" : \
+ __builtin_types_compatible_p(typeof(var), unsigned long)\
+ ? "%lu\n" : \
+ __builtin_types_compatible_p(typeof(var), int64_t) \
+ ? "%lli\n" : \
+ __builtin_types_compatible_p(typeof(var), uint64_t) \
+ ? "%llu\n" : \
+ __builtin_types_compatible_p(typeof(var), const char *) \
+ ? "%s\n" : "%i\n", var)
+
+ssize_t hprint(char *buf, int64_t v);
+
+bool is_zero(const char *p, size_t n);
+int parse_uuid(const char *s, char *uuid);
+
+ssize_t snprint_string_list(char *buf, size_t size, const char * const list[],
+ size_t selected);
+
+ssize_t read_string_list(const char *buf, const char * const list[]);
+
+struct time_stats {
+ /*
+ * all fields are in nanoseconds, averages are ewmas stored left shifted
+ * by 8
+ */
+ uint64_t max_duration;
+ uint64_t average_duration;
+ uint64_t average_frequency;
+ uint64_t last;
+};
+
+void time_stats_update(struct time_stats *stats, uint64_t time);
+
+#define NSEC_PER_ns 1L
+#define NSEC_PER_us NSEC_PER_USEC
+#define NSEC_PER_ms NSEC_PER_MSEC
+#define NSEC_PER_sec NSEC_PER_SEC
+
+#define __print_time_stat(stats, name, stat, units) \
+ sysfs_print(name ## _ ## stat ## _ ## units, \
+ div_u64((stats)->stat >> 8, NSEC_PER_ ## units))
+
+#define sysfs_print_time_stats(stats, name, \
+ frequency_units, \
+ duration_units) \
+do { \
+ __print_time_stat(stats, name, \
+ average_frequency, frequency_units); \
+ __print_time_stat(stats, name, \
+ average_duration, duration_units); \
+ __print_time_stat(stats, name, \
+ max_duration, duration_units); \
+ \
+ sysfs_print(name ## _last_ ## frequency_units, (stats)->last \
+ ? div_s64(local_clock() - (stats)->last, \
+ NSEC_PER_ ## frequency_units) \
+ : -1LL); \
+} while (0)
+
+#define sysfs_time_stats_attribute(name, \
+ frequency_units, \
+ duration_units) \
+read_attribute(name ## _average_frequency_ ## frequency_units); \
+read_attribute(name ## _average_duration_ ## duration_units); \
+read_attribute(name ## _max_duration_ ## duration_units); \
+read_attribute(name ## _last_ ## frequency_units)
+
+#define sysfs_time_stats_attribute_list(name, \
+ frequency_units, \
+ duration_units) \
+&sysfs_ ## name ## _average_frequency_ ## frequency_units, \
+&sysfs_ ## name ## _average_duration_ ## duration_units, \
+&sysfs_ ## name ## _max_duration_ ## duration_units, \
+&sysfs_ ## name ## _last_ ## frequency_units,
+
+#define ewma_add(ewma, val, weight, factor) \
+({ \
+ (ewma) *= (weight) - 1; \
+ (ewma) += (val) << factor; \
+ (ewma) /= (weight); \
+ (ewma) >> factor; \
+})
+
+struct ratelimit {
+ uint64_t next;
+ unsigned rate;
+};
+
+static inline void ratelimit_reset(struct ratelimit *d)
+{
+ d->next = local_clock();
+}
+
+unsigned next_delay(struct ratelimit *d, uint64_t done);
+
+#define __DIV_SAFE(n, d, zero) \
+({ \
+ typeof(n) _n = (n); \
+ typeof(d) _d = (d); \
+ _d ? _n / _d : zero; \
+})
+
+#define DIV_SAFE(n, d) __DIV_SAFE(n, d, 0)
+
+#define container_of_or_null(ptr, type, member) \
+({ \
+ typeof(ptr) _ptr = ptr; \
+ _ptr ? container_of(_ptr, type, member) : NULL; \
+})
+
+#define RB_INSERT(root, new, member, cmp) \
+({ \
+ __label__ dup; \
+ struct rb_node **n = &(root)->rb_node, *parent = NULL; \
+ typeof(new) this; \
+ int res, ret = -1; \
+ \
+ while (*n) { \
+ parent = *n; \
+ this = container_of(*n, typeof(*(new)), member); \
+ res = cmp(new, this); \
+ if (!res) \
+ goto dup; \
+ n = res < 0 \
+ ? &(*n)->rb_left \
+ : &(*n)->rb_right; \
+ } \
+ \
+ rb_link_node(&(new)->member, parent, n); \
+ rb_insert_color(&(new)->member, root); \
+ ret = 0; \
+dup: \
+ ret; \
+})
+
+#define RB_SEARCH(root, search, member, cmp) \
+({ \
+ struct rb_node *n = (root)->rb_node; \
+ typeof(&(search)) this, ret = NULL; \
+ int res; \
+ \
+ while (n) { \
+ this = container_of(n, typeof(search), member); \
+ res = cmp(&(search), this); \
+ if (!res) { \
+ ret = this; \
+ break; \
+ } \
+ n = res < 0 \
+ ? n->rb_left \
+ : n->rb_right; \
+ } \
+ ret; \
+})
+
+#define RB_GREATER(root, search, member, cmp) \
+({ \
+ struct rb_node *n = (root)->rb_node; \
+ typeof(&(search)) this, ret = NULL; \
+ int res; \
+ \
+ while (n) { \
+ this = container_of(n, typeof(search), member); \
+ res = cmp(&(search), this); \
+ if (res < 0) { \
+ ret = this; \
+ n = n->rb_left; \
+ } else \
+ n = n->rb_right; \
+ } \
+ ret; \
+})
+
+#define RB_FIRST(root, type, member) \
+ container_of_or_null(rb_first(root), type, member)
+
+#define RB_LAST(root, type, member) \
+ container_of_or_null(rb_last(root), type, member)
+
+#define RB_NEXT(ptr, member) \
+ container_of_or_null(rb_next(&(ptr)->member), typeof(*ptr), member)
+
+#define RB_PREV(ptr, member) \
+ container_of_or_null(rb_prev(&(ptr)->member), typeof(*ptr), member)
+
+/* Does linear interpolation between powers of two */
+static inline unsigned fract_exp_two(unsigned x, unsigned fract_bits)
+{
+ unsigned fract = x & ~(~0 << fract_bits);
+
+ x >>= fract_bits;
+ x = 1 << x;
+ x += (x * fract) >> fract_bits;
+
+ return x;
+}
+
+#define bio_end(bio) ((bio)->bi_sector + bio_sectors(bio))
+
+void bio_map(struct bio *bio, void *base);
+
+int bio_alloc_pages(struct bio *bio, gfp_t gfp);
+
+static inline sector_t bdev_sectors(struct block_device *bdev)
+{
+ return bdev->bd_inode->i_size >> 9;
+}
+
+#define closure_bio_submit(bio, cl, dev) \
+do { \
+ closure_get(cl); \
+ bch_generic_make_request(bio, &(dev)->bio_split_hook); \
+} while (0)
+
+uint64_t crc64_update(uint64_t, const void *, size_t);
+uint64_t crc64(const void *, size_t);
+
+#endif /* _BCACHE_UTIL_H */
--- /dev/null
+/*
+ * background writeback - scan btree for dirty data and write it to the backing
+ * device
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include "bcache.h"
+#include "btree.h"
+#include "debug.h"
+
+static struct workqueue_struct *dirty_wq;
+
+static void read_dirty(struct closure *);
+
+struct dirty_io {
+ struct closure cl;
+ struct cached_dev *dc;
+ struct bio bio;
+};
+
+/* Rate limiting */
+
+static void __update_writeback_rate(struct cached_dev *dc)
+{
+ struct cache_set *c = dc->disk.c;
+ uint64_t cache_sectors = c->nbuckets * c->sb.bucket_size;
+ uint64_t cache_dirty_target =
+ div_u64(cache_sectors * dc->writeback_percent, 100);
+
+ int64_t target = div64_u64(cache_dirty_target * bdev_sectors(dc->bdev),
+ c->cached_dev_sectors);
+
+ /* PD controller */
+
+ int change = 0;
+ int64_t error;
+ int64_t dirty = atomic_long_read(&dc->disk.sectors_dirty);
+ int64_t derivative = dirty - dc->disk.sectors_dirty_last;
+
+ dc->disk.sectors_dirty_last = dirty;
+
+ derivative *= dc->writeback_rate_d_term;
+ derivative = clamp(derivative, -dirty, dirty);
+
+ derivative = ewma_add(dc->disk.sectors_dirty_derivative, derivative,
+ dc->writeback_rate_d_smooth, 0);
+
+ /* Avoid divide by zero */
+ if (!target)
+ goto out;
+
+ error = div64_s64((dirty + derivative - target) << 8, target);
+
+ change = div_s64((dc->writeback_rate.rate * error) >> 8,
+ dc->writeback_rate_p_term_inverse);
+
+ /* Don't increase writeback rate if the device isn't keeping up */
+ if (change > 0 &&
+ time_after64(local_clock(),
+ dc->writeback_rate.next + 10 * NSEC_PER_MSEC))
+ change = 0;
+
+ dc->writeback_rate.rate =
+ clamp_t(int64_t, dc->writeback_rate.rate + change,
+ 1, NSEC_PER_MSEC);
+out:
+ dc->writeback_rate_derivative = derivative;
+ dc->writeback_rate_change = change;
+ dc->writeback_rate_target = target;
+
+ schedule_delayed_work(&dc->writeback_rate_update,
+ dc->writeback_rate_update_seconds * HZ);
+}
+
+static void update_writeback_rate(struct work_struct *work)
+{
+ struct cached_dev *dc = container_of(to_delayed_work(work),
+ struct cached_dev,
+ writeback_rate_update);
+
+ down_read(&dc->writeback_lock);
+
+ if (atomic_read(&dc->has_dirty) &&
+ dc->writeback_percent)
+ __update_writeback_rate(dc);
+
+ up_read(&dc->writeback_lock);
+}
+
+static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors)
+{
+ if (atomic_read(&dc->disk.detaching) ||
+ !dc->writeback_percent)
+ return 0;
+
+ return next_delay(&dc->writeback_rate, sectors * 10000000ULL);
+}
+
+/* Background writeback */
+
+static bool dirty_pred(struct keybuf *buf, struct bkey *k)
+{
+ return KEY_DIRTY(k);
+}
+
+static void dirty_init(struct keybuf_key *w)
+{
+ struct dirty_io *io = w->private;
+ struct bio *bio = &io->bio;
+
+ bio_init(bio);
+ if (!io->dc->writeback_percent)
+ bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
+
+ bio->bi_size = KEY_SIZE(&w->key) << 9;
+ bio->bi_max_vecs = DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS);
+ bio->bi_private = w;
+ bio->bi_io_vec = bio->bi_inline_vecs;
+ bio_map(bio, NULL);
+}
+
+static void refill_dirty(struct closure *cl)
+{
+ struct cached_dev *dc = container_of(cl, struct cached_dev,
+ writeback.cl);
+ struct keybuf *buf = &dc->writeback_keys;
+ bool searched_from_start = false;
+ struct bkey end = MAX_KEY;
+ SET_KEY_INODE(&end, dc->disk.id);
+
+ if (!atomic_read(&dc->disk.detaching) &&
+ !dc->writeback_running)
+ closure_return(cl);
+
+ down_write(&dc->writeback_lock);
+
+ if (!atomic_read(&dc->has_dirty)) {
+ SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
+ bch_write_bdev_super(dc, NULL);
+
+ up_write(&dc->writeback_lock);
+ closure_return(cl);
+ }
+
+ if (bkey_cmp(&buf->last_scanned, &end) >= 0) {
+ buf->last_scanned = KEY(dc->disk.id, 0, 0);
+ searched_from_start = true;
+ }
+
+ bch_refill_keybuf(dc->disk.c, buf, &end);
+
+ if (bkey_cmp(&buf->last_scanned, &end) >= 0 && searched_from_start) {
+ /* Searched the entire btree - delay awhile */
+
+ if (RB_EMPTY_ROOT(&buf->keys)) {
+ atomic_set(&dc->has_dirty, 0);
+ cached_dev_put(dc);
+ }
+
+ if (!atomic_read(&dc->disk.detaching))
+ closure_delay(&dc->writeback, dc->writeback_delay * HZ);
+ }
+
+ up_write(&dc->writeback_lock);
+
+ ratelimit_reset(&dc->writeback_rate);
+
+ /* Punt to workqueue only so we don't recurse and blow the stack */
+ continue_at(cl, read_dirty, dirty_wq);
+}
+
+void bch_writeback_queue(struct cached_dev *dc)
+{
+ if (closure_trylock(&dc->writeback.cl, &dc->disk.cl)) {
+ if (!atomic_read(&dc->disk.detaching))
+ closure_delay(&dc->writeback, dc->writeback_delay * HZ);
+
+ continue_at(&dc->writeback.cl, refill_dirty, dirty_wq);
+ }
+}
+
+void bch_writeback_add(struct cached_dev *dc, unsigned sectors)
+{
+ atomic_long_add(sectors, &dc->disk.sectors_dirty);
+
+ if (!atomic_read(&dc->has_dirty) &&
+ !atomic_xchg(&dc->has_dirty, 1)) {
+ atomic_inc(&dc->count);
+
+ if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
+ SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
+ /* XXX: should do this synchronously */
+ bch_write_bdev_super(dc, NULL);
+ }
+
+ bch_writeback_queue(dc);
+
+ if (dc->writeback_percent)
+ schedule_delayed_work(&dc->writeback_rate_update,
+ dc->writeback_rate_update_seconds * HZ);
+ }
+}
+
+/* Background writeback - IO loop */
+
+static void dirty_io_destructor(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+ kfree(io);
+}
+
+static void write_dirty_finish(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+ struct keybuf_key *w = io->bio.bi_private;
+ struct cached_dev *dc = io->dc;
+ struct bio_vec *bv = bio_iovec_idx(&io->bio, io->bio.bi_vcnt);
+
+ while (bv-- != io->bio.bi_io_vec)
+ __free_page(bv->bv_page);
+
+ /* This is kind of a dumb way of signalling errors. */
+ if (KEY_DIRTY(&w->key)) {
+ unsigned i;
+ struct btree_op op;
+ bch_btree_op_init_stack(&op);
+
+ op.type = BTREE_REPLACE;
+ bkey_copy(&op.replace, &w->key);
+
+ SET_KEY_DIRTY(&w->key, false);
+ bch_keylist_add(&op.keys, &w->key);
+
+ for (i = 0; i < KEY_PTRS(&w->key); i++)
+ atomic_inc(&PTR_BUCKET(dc->disk.c, &w->key, i)->pin);
+
+ pr_debug("clearing %s", pkey(&w->key));
+ bch_btree_insert(&op, dc->disk.c);
+ closure_sync(&op.cl);
+
+ atomic_long_inc(op.insert_collision
+ ? &dc->disk.c->writeback_keys_failed
+ : &dc->disk.c->writeback_keys_done);
+ }
+
+ bch_keybuf_del(&dc->writeback_keys, w);
+ atomic_dec_bug(&dc->in_flight);
+
+ closure_wake_up(&dc->writeback_wait);
+
+ closure_return_with_destructor(cl, dirty_io_destructor);
+}
+
+static void dirty_endio(struct bio *bio, int error)
+{
+ struct keybuf_key *w = bio->bi_private;
+ struct dirty_io *io = w->private;
+
+ if (error)
+ SET_KEY_DIRTY(&w->key, false);
+
+ closure_put(&io->cl);
+}
+
+static void write_dirty(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+ struct keybuf_key *w = io->bio.bi_private;
+
+ dirty_init(w);
+ io->bio.bi_rw = WRITE;
+ io->bio.bi_sector = KEY_START(&w->key);
+ io->bio.bi_bdev = io->dc->bdev;
+ io->bio.bi_end_io = dirty_endio;
+
+ trace_bcache_write_dirty(&io->bio);
+ closure_bio_submit(&io->bio, cl, &io->dc->disk);
+
+ continue_at(cl, write_dirty_finish, dirty_wq);
+}
+
+static void read_dirty_endio(struct bio *bio, int error)
+{
+ struct keybuf_key *w = bio->bi_private;
+ struct dirty_io *io = w->private;
+
+ bch_count_io_errors(PTR_CACHE(io->dc->disk.c, &w->key, 0),
+ error, "reading dirty data from cache");
+
+ dirty_endio(bio, error);
+}
+
+static void read_dirty_submit(struct closure *cl)
+{
+ struct dirty_io *io = container_of(cl, struct dirty_io, cl);
+
+ trace_bcache_read_dirty(&io->bio);
+ closure_bio_submit(&io->bio, cl, &io->dc->disk);
+
+ continue_at(cl, write_dirty, dirty_wq);
+}
+
+static void read_dirty(struct closure *cl)
+{
+ struct cached_dev *dc = container_of(cl, struct cached_dev,
+ writeback.cl);
+ unsigned delay = writeback_delay(dc, 0);
+ struct keybuf_key *w;
+ struct dirty_io *io;
+
+ /*
+ * XXX: if we error, background writeback just spins. Should use some
+ * mempools.
+ */
+
+ while (1) {
+ w = bch_keybuf_next(&dc->writeback_keys);
+ if (!w)
+ break;
+
+ BUG_ON(ptr_stale(dc->disk.c, &w->key, 0));
+
+ if (delay > 0 &&
+ (KEY_START(&w->key) != dc->last_read ||
+ jiffies_to_msecs(delay) > 50)) {
+ w->private = NULL;
+
+ closure_delay(&dc->writeback, delay);
+ continue_at(cl, read_dirty, dirty_wq);
+ }
+
+ dc->last_read = KEY_OFFSET(&w->key);
+
+ io = kzalloc(sizeof(struct dirty_io) + sizeof(struct bio_vec)
+ * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS),
+ GFP_KERNEL);
+ if (!io)
+ goto err;
+
+ w->private = io;
+ io->dc = dc;
+
+ dirty_init(w);
+ io->bio.bi_sector = PTR_OFFSET(&w->key, 0);
+ io->bio.bi_bdev = PTR_CACHE(dc->disk.c,
+ &w->key, 0)->bdev;
+ io->bio.bi_rw = READ;
+ io->bio.bi_end_io = read_dirty_endio;
+
+ if (bio_alloc_pages(&io->bio, GFP_KERNEL))
+ goto err_free;
+
+ pr_debug("%s", pkey(&w->key));
+
+ closure_call(&io->cl, read_dirty_submit, NULL, &dc->disk.cl);
+
+ delay = writeback_delay(dc, KEY_SIZE(&w->key));
+
+ atomic_inc(&dc->in_flight);
+
+ if (!closure_wait_event(&dc->writeback_wait, cl,
+ atomic_read(&dc->in_flight) < 64))
+ continue_at(cl, read_dirty, dirty_wq);
+ }
+
+ if (0) {
+err_free:
+ kfree(w->private);
+err:
+ bch_keybuf_del(&dc->writeback_keys, w);
+ }
+
+ refill_dirty(cl);
+}
+
+void bch_writeback_init_cached_dev(struct cached_dev *dc)
+{
+ closure_init_unlocked(&dc->writeback);
+ init_rwsem(&dc->writeback_lock);
+
+ bch_keybuf_init(&dc->writeback_keys, dirty_pred);
+
+ dc->writeback_metadata = true;
+ dc->writeback_running = true;
+ dc->writeback_percent = 10;
+ dc->writeback_delay = 30;
+ dc->writeback_rate.rate = 1024;
+
+ dc->writeback_rate_update_seconds = 30;
+ dc->writeback_rate_d_term = 16;
+ dc->writeback_rate_p_term_inverse = 64;
+ dc->writeback_rate_d_smooth = 8;
+
+ INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate);
+ schedule_delayed_work(&dc->writeback_rate_update,
+ dc->writeback_rate_update_seconds * HZ);
+}
+
+void bch_writeback_exit(void)
+{
+ if (dirty_wq)
+ destroy_workqueue(dirty_wq);
+}
+
+int __init bch_writeback_init(void)
+{
+ dirty_wq = create_singlethread_workqueue("bcache_writeback");
+ if (!dirty_wq)
+ return -ENOMEM;
+
+ return 0;
+}
#endif
/* */
+
+#ifdef CONFIG_CGROUP_BCACHE
+SUBSYS(bcache)
+#endif
+
+/* */
#ifdef CONFIG_UPROBES
struct uprobe_task *utask;
#endif
+#if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
+ unsigned int sequential_io;
+ unsigned int sequential_io_avg;
+#endif
};
/* Future-safe accessor for struct task_struct's cpus_allowed. */
--- /dev/null
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bcache
+
+#if !defined(_TRACE_BCACHE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BCACHE_H
+
+#include <linux/tracepoint.h>
+
+struct search;
+
+DECLARE_EVENT_CLASS(bcache_request,
+
+ TP_PROTO(struct search *s, struct bio *bio),
+
+ TP_ARGS(s, bio),
+
+ TP_STRUCT__entry(
+ __field(dev_t, dev )
+ __field(unsigned int, orig_major )
+ __field(unsigned int, orig_minor )
+ __field(sector_t, sector )
+ __field(dev_t, orig_sector )
+ __field(unsigned int, nr_sector )
+ __array(char, rwbs, 6 )
+ __array(char, comm, TASK_COMM_LEN )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = bio->bi_bdev->bd_dev;
+ __entry->orig_major = s->d->disk->major;
+ __entry->orig_minor = s->d->disk->first_minor;
+ __entry->sector = bio->bi_sector;
+ __entry->orig_sector = bio->bi_sector - 16;
+ __entry->nr_sector = bio->bi_size >> 9;
+ blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+ memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ ),
+
+ TP_printk("%d,%d %s %llu + %u [%s] (from %d,%d @ %llu)",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->rwbs,
+ (unsigned long long)__entry->sector,
+ __entry->nr_sector, __entry->comm,
+ __entry->orig_major, __entry->orig_minor,
+ (unsigned long long)__entry->orig_sector)
+);
+
+DEFINE_EVENT(bcache_request, bcache_request_start,
+
+ TP_PROTO(struct search *s, struct bio *bio),
+
+ TP_ARGS(s, bio)
+);
+
+DEFINE_EVENT(bcache_request, bcache_request_end,
+
+ TP_PROTO(struct search *s, struct bio *bio),
+
+ TP_ARGS(s, bio)
+);
+
+DECLARE_EVENT_CLASS(bcache_bio,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio),
+
+ TP_STRUCT__entry(
+ __field(dev_t, dev )
+ __field(sector_t, sector )
+ __field(unsigned int, nr_sector )
+ __array(char, rwbs, 6 )
+ __array(char, comm, TASK_COMM_LEN )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = bio->bi_bdev->bd_dev;
+ __entry->sector = bio->bi_sector;
+ __entry->nr_sector = bio->bi_size >> 9;
+ blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+ memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ ),
+
+ TP_printk("%d,%d %s %llu + %u [%s]",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->rwbs,
+ (unsigned long long)__entry->sector,
+ __entry->nr_sector, __entry->comm)
+);
+
+
+DEFINE_EVENT(bcache_bio, bcache_passthrough,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_cache_hit,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_cache_miss,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_read_retry,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_writethrough,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_writeback,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_write_skip,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_btree_read,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_btree_write,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_write_dirty,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_read_dirty,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_write_moving,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_read_moving,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DEFINE_EVENT(bcache_bio, bcache_journal_write,
+
+ TP_PROTO(struct bio *bio),
+
+ TP_ARGS(bio)
+);
+
+DECLARE_EVENT_CLASS(bcache_cache_bio,
+
+ TP_PROTO(struct bio *bio,
+ sector_t orig_sector,
+ struct block_device* orig_bdev),
+
+ TP_ARGS(bio, orig_sector, orig_bdev),
+
+ TP_STRUCT__entry(
+ __field(dev_t, dev )
+ __field(dev_t, orig_dev )
+ __field(sector_t, sector )
+ __field(sector_t, orig_sector )
+ __field(unsigned int, nr_sector )
+ __array(char, rwbs, 6 )
+ __array(char, comm, TASK_COMM_LEN )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = bio->bi_bdev->bd_dev;
+ __entry->orig_dev = orig_bdev->bd_dev;
+ __entry->sector = bio->bi_sector;
+ __entry->orig_sector = orig_sector;
+ __entry->nr_sector = bio->bi_size >> 9;
+ blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
+ memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
+ ),
+
+ TP_printk("%d,%d %s %llu + %u [%s] (from %d,%d %llu)",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->rwbs,
+ (unsigned long long)__entry->sector,
+ __entry->nr_sector, __entry->comm,
+ MAJOR(__entry->orig_dev), MINOR(__entry->orig_dev),
+ (unsigned long long)__entry->orig_sector)
+);
+
+DEFINE_EVENT(bcache_cache_bio, bcache_cache_insert,
+
+ TP_PROTO(struct bio *bio,
+ sector_t orig_sector,
+ struct block_device *orig_bdev),
+
+ TP_ARGS(bio, orig_sector, orig_bdev)
+);
+
+DECLARE_EVENT_CLASS(bcache_gc,
+
+ TP_PROTO(uint8_t *uuid),
+
+ TP_ARGS(uuid),
+
+ TP_STRUCT__entry(
+ __field(uint8_t *, uuid)
+ ),
+
+ TP_fast_assign(
+ __entry->uuid = uuid;
+ ),
+
+ TP_printk("%pU", __entry->uuid)
+);
+
+
+DEFINE_EVENT(bcache_gc, bcache_gc_start,
+
+ TP_PROTO(uint8_t *uuid),
+
+ TP_ARGS(uuid)
+);
+
+DEFINE_EVENT(bcache_gc, bcache_gc_end,
+
+ TP_PROTO(uint8_t *uuid),
+
+ TP_ARGS(uuid)
+);
+
+#endif /* _TRACE_BCACHE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
p->memcg_batch.do_batch = 0;
p->memcg_batch.memcg = NULL;
#endif
+#ifdef CONFIG_BCACHE
+ p->sequential_io = 0;
+ p->sequential_io_avg = 0;
+#endif
/* Perform scheduler related setup. Assign this task to a CPU. */
sched_fork(p);
projects / platform / kernel / linux-rpi.git / commitdiff