#include "fuse_i.h"
#include <linux/dax.h>
+#include <linux/uio.h>
#include <linux/pfn_t.h>
+#include <linux/iomap.h>
+#include <linux/interval_tree.h>
/*
* Default memory range size. A power of 2 so it agrees with common FUSE_INIT
/* Will connect in fcd->free_ranges to keep track of free memory */
struct list_head list;
+ /* For interval tree in file/inode */
+ struct interval_tree_node itn;
+
/** Position in DAX window */
u64 window_offset;
/** Length of mapping, in bytes */
loff_t length;
+
+ /* Is this mapping read-only or read-write */
+ bool writable;
+};
+
+/* Per-inode dax map */
+struct fuse_inode_dax {
+ /* Semaphore to protect modifications to the dmap tree */
+ struct rw_semaphore sem;
+
+ /* Sorted rb tree of struct fuse_dax_mapping elements */
+ struct rb_root_cached tree;
+ unsigned long nr;
};
struct fuse_conn_dax {
/* DAX device */
struct dax_device *dev;
+ /* Lock protecting accessess to members of this structure */
+ spinlock_t lock;
+
/* DAX Window Free Ranges */
long nr_free_ranges;
struct list_head free_ranges;
};
+static inline struct fuse_dax_mapping *
+node_to_dmap(struct interval_tree_node *node)
+{
+ if (!node)
+ return NULL;
+
+ return container_of(node, struct fuse_dax_mapping, itn);
+}
+
+static struct fuse_dax_mapping *alloc_dax_mapping(struct fuse_conn_dax *fcd)
+{
+ struct fuse_dax_mapping *dmap;
+
+ spin_lock(&fcd->lock);
+ dmap = list_first_entry_or_null(&fcd->free_ranges,
+ struct fuse_dax_mapping, list);
+ if (dmap) {
+ list_del_init(&dmap->list);
+ WARN_ON(fcd->nr_free_ranges <= 0);
+ fcd->nr_free_ranges--;
+ }
+ spin_unlock(&fcd->lock);
+ return dmap;
+}
+
+/* This assumes fcd->lock is held */
+static void __dmap_add_to_free_pool(struct fuse_conn_dax *fcd,
+ struct fuse_dax_mapping *dmap)
+{
+ list_add_tail(&dmap->list, &fcd->free_ranges);
+ fcd->nr_free_ranges++;
+}
+
+static void dmap_add_to_free_pool(struct fuse_conn_dax *fcd,
+ struct fuse_dax_mapping *dmap)
+{
+ /* Return fuse_dax_mapping to free list */
+ spin_lock(&fcd->lock);
+ __dmap_add_to_free_pool(fcd, dmap);
+ spin_unlock(&fcd->lock);
+}
+
+static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx,
+ struct fuse_dax_mapping *dmap, bool writable,
+ bool upgrade)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_conn_dax *fcd = fc->dax;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_setupmapping_in inarg;
+ loff_t offset = start_idx << FUSE_DAX_SHIFT;
+ FUSE_ARGS(args);
+ ssize_t err;
+
+ WARN_ON(fcd->nr_free_ranges < 0);
+
+ /* Ask fuse daemon to setup mapping */
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.foffset = offset;
+ inarg.fh = -1;
+ inarg.moffset = dmap->window_offset;
+ inarg.len = FUSE_DAX_SZ;
+ inarg.flags |= FUSE_SETUPMAPPING_FLAG_READ;
+ if (writable)
+ inarg.flags |= FUSE_SETUPMAPPING_FLAG_WRITE;
+ args.opcode = FUSE_SETUPMAPPING;
+ args.nodeid = fi->nodeid;
+ args.in_numargs = 1;
+ args.in_args[0].size = sizeof(inarg);
+ args.in_args[0].value = &inarg;
+ err = fuse_simple_request(fc, &args);
+ if (err < 0)
+ return err;
+ dmap->writable = writable;
+ if (!upgrade) {
+ dmap->itn.start = dmap->itn.last = start_idx;
+ /* Protected by fi->dax->sem */
+ interval_tree_insert(&dmap->itn, &fi->dax->tree);
+ fi->dax->nr++;
+ }
+ return 0;
+}
+
+static int fuse_send_removemapping(struct inode *inode,
+ struct fuse_removemapping_in *inargp,
+ struct fuse_removemapping_one *remove_one)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ FUSE_ARGS(args);
+
+ args.opcode = FUSE_REMOVEMAPPING;
+ args.nodeid = fi->nodeid;
+ args.in_numargs = 2;
+ args.in_args[0].size = sizeof(*inargp);
+ args.in_args[0].value = inargp;
+ args.in_args[1].size = inargp->count * sizeof(*remove_one);
+ args.in_args[1].value = remove_one;
+ return fuse_simple_request(fc, &args);
+}
+
+static int dmap_removemapping_list(struct inode *inode, unsigned int num,
+ struct list_head *to_remove)
+{
+ struct fuse_removemapping_one *remove_one, *ptr;
+ struct fuse_removemapping_in inarg;
+ struct fuse_dax_mapping *dmap;
+ int ret, i = 0, nr_alloc;
+
+ nr_alloc = min_t(unsigned int, num, FUSE_REMOVEMAPPING_MAX_ENTRY);
+ remove_one = kmalloc_array(nr_alloc, sizeof(*remove_one), GFP_NOFS);
+ if (!remove_one)
+ return -ENOMEM;
+
+ ptr = remove_one;
+ list_for_each_entry(dmap, to_remove, list) {
+ ptr->moffset = dmap->window_offset;
+ ptr->len = dmap->length;
+ ptr++;
+ i++;
+ num--;
+ if (i >= nr_alloc || num == 0) {
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.count = i;
+ ret = fuse_send_removemapping(inode, &inarg,
+ remove_one);
+ if (ret)
+ goto out;
+ ptr = remove_one;
+ i = 0;
+ }
+ }
+out:
+ kfree(remove_one);
+ return ret;
+}
+
+/*
+ * Cleanup dmap entry and add back to free list. This should be called with
+ * fcd->lock held.
+ */
+static void dmap_reinit_add_to_free_pool(struct fuse_conn_dax *fcd,
+ struct fuse_dax_mapping *dmap)
+{
+ pr_debug("fuse: freeing memory range start_idx=0x%lx end_idx=0x%lx window_offset=0x%llx length=0x%llx\n",
+ dmap->itn.start, dmap->itn.last, dmap->window_offset,
+ dmap->length);
+ dmap->itn.start = dmap->itn.last = 0;
+ __dmap_add_to_free_pool(fcd, dmap);
+}
+
+/*
+ * Free inode dmap entries whose range falls inside [start, end].
+ * Does not take any locks. At this point of time it should only be
+ * called from evict_inode() path where we know all dmap entries can be
+ * reclaimed.
+ */
+static void inode_reclaim_dmap_range(struct fuse_conn_dax *fcd,
+ struct inode *inode,
+ loff_t start, loff_t end)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_dax_mapping *dmap, *n;
+ int err, num = 0;
+ LIST_HEAD(to_remove);
+ unsigned long start_idx = start >> FUSE_DAX_SHIFT;
+ unsigned long end_idx = end >> FUSE_DAX_SHIFT;
+ struct interval_tree_node *node;
+
+ while (1) {
+ node = interval_tree_iter_first(&fi->dax->tree, start_idx,
+ end_idx);
+ if (!node)
+ break;
+ dmap = node_to_dmap(node);
+ interval_tree_remove(&dmap->itn, &fi->dax->tree);
+ num++;
+ list_add(&dmap->list, &to_remove);
+ }
+
+ /* Nothing to remove */
+ if (list_empty(&to_remove))
+ return;
+
+ WARN_ON(fi->dax->nr < num);
+ fi->dax->nr -= num;
+ err = dmap_removemapping_list(inode, num, &to_remove);
+ if (err && err != -ENOTCONN) {
+ pr_warn("Failed to removemappings. start=0x%llx end=0x%llx\n",
+ start, end);
+ }
+ spin_lock(&fcd->lock);
+ list_for_each_entry_safe(dmap, n, &to_remove, list) {
+ list_del_init(&dmap->list);
+ dmap_reinit_add_to_free_pool(fcd, dmap);
+ }
+ spin_unlock(&fcd->lock);
+}
+
+/*
+ * It is called from evict_inode() and by that time inode is going away. So
+ * this function does not take any locks like fi->dax->sem for traversing
+ * that fuse inode interval tree. If that lock is taken then lock validator
+ * complains of deadlock situation w.r.t fs_reclaim lock.
+ */
+void fuse_dax_inode_cleanup(struct inode *inode)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ /*
+ * fuse_evict_inode() has already called truncate_inode_pages_final()
+ * before we arrive here. So we should not have to worry about any
+ * pages/exception entries still associated with inode.
+ */
+ inode_reclaim_dmap_range(fc->dax, inode, 0, -1);
+ WARN_ON(fi->dax->nr);
+}
+
+static void fuse_fill_iomap_hole(struct iomap *iomap, loff_t length)
+{
+ iomap->addr = IOMAP_NULL_ADDR;
+ iomap->length = length;
+ iomap->type = IOMAP_HOLE;
+}
+
+static void fuse_fill_iomap(struct inode *inode, loff_t pos, loff_t length,
+ struct iomap *iomap, struct fuse_dax_mapping *dmap,
+ unsigned int flags)
+{
+ loff_t offset, len;
+ loff_t i_size = i_size_read(inode);
+
+ offset = pos - (dmap->itn.start << FUSE_DAX_SHIFT);
+ len = min(length, dmap->length - offset);
+
+ /* If length is beyond end of file, truncate further */
+ if (pos + len > i_size)
+ len = i_size - pos;
+
+ if (len > 0) {
+ iomap->addr = dmap->window_offset + offset;
+ iomap->length = len;
+ if (flags & IOMAP_FAULT)
+ iomap->length = ALIGN(len, PAGE_SIZE);
+ iomap->type = IOMAP_MAPPED;
+ } else {
+ /* Mapping beyond end of file is hole */
+ fuse_fill_iomap_hole(iomap, length);
+ }
+}
+
+static int fuse_setup_new_dax_mapping(struct inode *inode, loff_t pos,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_conn_dax *fcd = fc->dax;
+ struct fuse_dax_mapping *dmap, *alloc_dmap = NULL;
+ int ret;
+ bool writable = flags & IOMAP_WRITE;
+ unsigned long start_idx = pos >> FUSE_DAX_SHIFT;
+ struct interval_tree_node *node;
+
+ alloc_dmap = alloc_dax_mapping(fcd);
+ if (!alloc_dmap)
+ return -EIO;
+
+ /*
+ * Take write lock so that only one caller can try to setup mapping
+ * and other waits.
+ */
+ down_write(&fi->dax->sem);
+ /*
+ * We dropped lock. Check again if somebody else setup
+ * mapping already.
+ */
+ node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx);
+ if (node) {
+ dmap = node_to_dmap(node);
+ fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
+ dmap_add_to_free_pool(fcd, alloc_dmap);
+ up_write(&fi->dax->sem);
+ return 0;
+ }
+
+ /* Setup one mapping */
+ ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, alloc_dmap,
+ writable, false);
+ if (ret < 0) {
+ dmap_add_to_free_pool(fcd, alloc_dmap);
+ up_write(&fi->dax->sem);
+ return ret;
+ }
+ fuse_fill_iomap(inode, pos, length, iomap, alloc_dmap, flags);
+ up_write(&fi->dax->sem);
+ return 0;
+}
+
+static int fuse_upgrade_dax_mapping(struct inode *inode, loff_t pos,
+ loff_t length, unsigned int flags,
+ struct iomap *iomap)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_dax_mapping *dmap;
+ int ret;
+ unsigned long idx = pos >> FUSE_DAX_SHIFT;
+ struct interval_tree_node *node;
+
+ /*
+ * Take exclusive lock so that only one caller can try to setup
+ * mapping and others wait.
+ */
+ down_write(&fi->dax->sem);
+ node = interval_tree_iter_first(&fi->dax->tree, idx, idx);
+
+ /* We are holding either inode lock or i_mmap_sem, and that should
+ * ensure that dmap can't reclaimed or truncated and it should still
+ * be there in tree despite the fact we dropped and re-acquired the
+ * lock.
+ */
+ ret = -EIO;
+ if (WARN_ON(!node))
+ goto out_err;
+
+ dmap = node_to_dmap(node);
+
+ /* Maybe another thread already upgraded mapping while we were not
+ * holding lock.
+ */
+ if (dmap->writable) {
+ ret = 0;
+ goto out_fill_iomap;
+ }
+
+ ret = fuse_setup_one_mapping(inode, pos >> FUSE_DAX_SHIFT, dmap, true,
+ true);
+ if (ret < 0)
+ goto out_err;
+out_fill_iomap:
+ fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
+out_err:
+ up_write(&fi->dax->sem);
+ return ret;
+}
+
+/* This is just for DAX and the mapping is ephemeral, do not use it for other
+ * purposes since there is no block device with a permanent mapping.
+ */
+static int fuse_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
+ unsigned int flags, struct iomap *iomap,
+ struct iomap *srcmap)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_dax_mapping *dmap;
+ bool writable = flags & IOMAP_WRITE;
+ unsigned long start_idx = pos >> FUSE_DAX_SHIFT;
+ struct interval_tree_node *node;
+
+ /* We don't support FIEMAP */
+ if (WARN_ON(flags & IOMAP_REPORT))
+ return -EIO;
+
+ iomap->offset = pos;
+ iomap->flags = 0;
+ iomap->bdev = NULL;
+ iomap->dax_dev = fc->dax->dev;
+
+ /*
+ * Both read/write and mmap path can race here. So we need something
+ * to make sure if we are setting up mapping, then other path waits
+ *
+ * For now, use a semaphore for this. It probably needs to be
+ * optimized later.
+ */
+ down_read(&fi->dax->sem);
+ node = interval_tree_iter_first(&fi->dax->tree, start_idx, start_idx);
+ if (node) {
+ dmap = node_to_dmap(node);
+ if (writable && !dmap->writable) {
+ /* Upgrade read-only mapping to read-write. This will
+ * require exclusive fi->dax->sem lock as we don't want
+ * two threads to be trying to this simultaneously
+ * for same dmap. So drop shared lock and acquire
+ * exclusive lock.
+ */
+ up_read(&fi->dax->sem);
+ pr_debug("%s: Upgrading mapping at offset 0x%llx length 0x%llx\n",
+ __func__, pos, length);
+ return fuse_upgrade_dax_mapping(inode, pos, length,
+ flags, iomap);
+ } else {
+ fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
+ up_read(&fi->dax->sem);
+ return 0;
+ }
+ } else {
+ up_read(&fi->dax->sem);
+ pr_debug("%s: no mapping at offset 0x%llx length 0x%llx\n",
+ __func__, pos, length);
+ if (pos >= i_size_read(inode))
+ goto iomap_hole;
+
+ return fuse_setup_new_dax_mapping(inode, pos, length, flags,
+ iomap);
+ }
+
+ /*
+ * If read beyond end of file happnes, fs code seems to return
+ * it as hole
+ */
+iomap_hole:
+ fuse_fill_iomap_hole(iomap, length);
+ pr_debug("%s returning hole mapping. pos=0x%llx length_asked=0x%llx length_returned=0x%llx\n",
+ __func__, pos, length, iomap->length);
+ return 0;
+}
+
+static int fuse_iomap_end(struct inode *inode, loff_t pos, loff_t length,
+ ssize_t written, unsigned int flags,
+ struct iomap *iomap)
+{
+ /* DAX writes beyond end-of-file aren't handled using iomap, so the
+ * file size is unchanged and there is nothing to do here.
+ */
+ return 0;
+}
+
+static const struct iomap_ops fuse_iomap_ops = {
+ .iomap_begin = fuse_iomap_begin,
+ .iomap_end = fuse_iomap_end,
+};
+
+ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ ssize_t ret;
+
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (!inode_trylock_shared(inode))
+ return -EAGAIN;
+ } else {
+ inode_lock_shared(inode);
+ }
+
+ ret = dax_iomap_rw(iocb, to, &fuse_iomap_ops);
+ inode_unlock_shared(inode);
+
+ /* TODO file_accessed(iocb->f_filp) */
+ return ret;
+}
+
+static bool file_extending_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+
+ return (iov_iter_rw(from) == WRITE &&
+ ((iocb->ki_pos) >= i_size_read(inode) ||
+ (iocb->ki_pos + iov_iter_count(from) > i_size_read(inode))));
+}
+
+static ssize_t fuse_dax_direct_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
+ ssize_t ret;
+
+ ret = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE);
+ if (ret < 0)
+ return ret;
+
+ fuse_invalidate_attr(inode);
+ fuse_write_update_size(inode, iocb->ki_pos);
+ return ret;
+}
+
+ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ ssize_t ret;
+
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ if (!inode_trylock(inode))
+ return -EAGAIN;
+ } else {
+ inode_lock(inode);
+ }
+
+ ret = generic_write_checks(iocb, from);
+ if (ret <= 0)
+ goto out;
+
+ ret = file_remove_privs(iocb->ki_filp);
+ if (ret)
+ goto out;
+ /* TODO file_update_time() but we don't want metadata I/O */
+
+ /* Do not use dax for file extending writes as write and on
+ * disk i_size increase are not atomic otherwise.
+ */
+ if (file_extending_write(iocb, from))
+ ret = fuse_dax_direct_write(iocb, from);
+ else
+ ret = dax_iomap_rw(iocb, from, &fuse_iomap_ops);
+
+out:
+ inode_unlock(inode);
+
+ if (ret > 0)
+ ret = generic_write_sync(iocb, ret);
+ return ret;
+}
+
static void fuse_free_dax_mem_ranges(struct list_head *mem_list)
{
struct fuse_dax_mapping *range, *temp;
if (!fcd)
return -ENOMEM;
+ spin_lock_init(&fcd->lock);
fcd->dev = dax_dev;
err = fuse_dax_mem_range_init(fcd);
if (err) {
return 0;
}
+bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi)
+{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
+
+ fi->dax = NULL;
+ if (fc->dax) {
+ fi->dax = kzalloc(sizeof(*fi->dax), GFP_KERNEL_ACCOUNT);
+ if (!fi->dax)
+ return false;
+
+ init_rwsem(&fi->dax->sem);
+ fi->dax->tree = RB_ROOT_CACHED;
+ }
+
+ return true;
+}
+
+void fuse_dax_inode_init(struct inode *inode)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ if (!fc->dax)
+ return;
+
+ inode->i_flags |= S_DAX;
+}
+
bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment)
{
if (fc->dax && (map_alignment > FUSE_DAX_SHIFT)) {
projects / platform / kernel / linux-rpi.git / commitdiff