1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2011 STRATO. All rights reserved.
6 #include <linux/sched.h>
7 #include <linux/pagemap.h>
8 #include <linux/writeback.h>
9 #include <linux/blkdev.h>
10 #include <linux/slab.h>
11 #include <linux/workqueue.h>
15 #include "transaction.h"
16 #include "dev-replace.h"
17 #include "block-group.h"
22 * This is the implementation for the generic read ahead framework.
24 * To trigger a readahead, btrfs_reada_add must be called. It will start
25 * a read ahead for the given range [start, end) on tree root. The returned
26 * handle can either be used to wait on the readahead to finish
27 * (btrfs_reada_wait), or to send it to the background (btrfs_reada_detach).
29 * The read ahead works as follows:
30 * On btrfs_reada_add, the root of the tree is inserted into a radix_tree.
31 * reada_start_machine will then search for extents to prefetch and trigger
32 * some reads. When a read finishes for a node, all contained node/leaf
33 * pointers that lie in the given range will also be enqueued. The reads will
34 * be triggered in sequential order, thus giving a big win over a naive
35 * enumeration. It will also make use of multi-device layouts. Each disk
36 * will have its on read pointer and all disks will by utilized in parallel.
37 * Also will no two disks read both sides of a mirror simultaneously, as this
38 * would waste seeking capacity. Instead both disks will read different parts
40 * Any number of readaheads can be started in parallel. The read order will be
41 * determined globally, i.e. 2 parallel readaheads will normally finish faster
42 * than the 2 started one after another.
45 #define MAX_IN_FLIGHT 6
48 struct list_head list;
49 struct reada_control *rc;
56 struct list_head extctl;
59 struct reada_zone *zones[BTRFS_MAX_MIRRORS];
68 struct list_head list;
71 struct btrfs_device *device;
72 struct btrfs_device *devs[BTRFS_MAX_MIRRORS]; /* full list, incl
78 struct reada_machine_work {
79 struct btrfs_work work;
80 struct btrfs_fs_info *fs_info;
83 static void reada_extent_put(struct btrfs_fs_info *, struct reada_extent *);
84 static void reada_control_release(struct kref *kref);
85 static void reada_zone_release(struct kref *kref);
86 static void reada_start_machine(struct btrfs_fs_info *fs_info);
87 static void __reada_start_machine(struct btrfs_fs_info *fs_info);
89 static int reada_add_block(struct reada_control *rc, u64 logical,
90 struct btrfs_key *top, u64 generation);
93 /* in case of err, eb might be NULL */
94 static void __readahead_hook(struct btrfs_fs_info *fs_info,
95 struct reada_extent *re, struct extent_buffer *eb,
102 struct list_head list;
104 spin_lock(&re->lock);
106 * just take the full list from the extent. afterwards we
107 * don't need the lock anymore
109 list_replace_init(&re->extctl, &list);
111 spin_unlock(&re->lock);
114 * this is the error case, the extent buffer has not been
115 * read correctly. We won't access anything from it and
116 * just cleanup our data structures. Effectively this will
117 * cut the branch below this node from read ahead.
123 * FIXME: currently we just set nritems to 0 if this is a leaf,
124 * effectively ignoring the content. In a next step we could
125 * trigger more readahead depending from the content, e.g.
126 * fetch the checksums for the extents in the leaf.
128 if (!btrfs_header_level(eb))
131 nritems = btrfs_header_nritems(eb);
132 generation = btrfs_header_generation(eb);
133 for (i = 0; i < nritems; i++) {
134 struct reada_extctl *rec;
136 struct btrfs_key key;
137 struct btrfs_key next_key;
139 btrfs_node_key_to_cpu(eb, &key, i);
141 btrfs_node_key_to_cpu(eb, &next_key, i + 1);
144 bytenr = btrfs_node_blockptr(eb, i);
145 n_gen = btrfs_node_ptr_generation(eb, i);
147 list_for_each_entry(rec, &list, list) {
148 struct reada_control *rc = rec->rc;
151 * if the generation doesn't match, just ignore this
152 * extctl. This will probably cut off a branch from
153 * prefetch. Alternatively one could start a new (sub-)
154 * prefetch for this branch, starting again from root.
155 * FIXME: move the generation check out of this loop
158 if (rec->generation != generation) {
160 "generation mismatch for (%llu,%d,%llu) %llu != %llu",
161 key.objectid, key.type, key.offset,
162 rec->generation, generation);
165 if (rec->generation == generation &&
166 btrfs_comp_cpu_keys(&key, &rc->key_end) < 0 &&
167 btrfs_comp_cpu_keys(&next_key, &rc->key_start) > 0)
168 reada_add_block(rc, bytenr, &next_key, n_gen);
174 * free extctl records
176 while (!list_empty(&list)) {
177 struct reada_control *rc;
178 struct reada_extctl *rec;
180 rec = list_first_entry(&list, struct reada_extctl, list);
181 list_del(&rec->list);
185 kref_get(&rc->refcnt);
186 if (atomic_dec_and_test(&rc->elems)) {
187 kref_put(&rc->refcnt, reada_control_release);
190 kref_put(&rc->refcnt, reada_control_release);
192 reada_extent_put(fs_info, re); /* one ref for each entry */
198 int btree_readahead_hook(struct extent_buffer *eb, int err)
200 struct btrfs_fs_info *fs_info = eb->fs_info;
202 struct reada_extent *re;
205 spin_lock(&fs_info->reada_lock);
206 re = radix_tree_lookup(&fs_info->reada_tree,
207 eb->start >> PAGE_SHIFT);
210 spin_unlock(&fs_info->reada_lock);
216 __readahead_hook(fs_info, re, eb, err);
217 reada_extent_put(fs_info, re); /* our ref */
220 reada_start_machine(fs_info);
224 static struct reada_zone *reada_find_zone(struct btrfs_device *dev, u64 logical,
225 struct btrfs_bio *bbio)
227 struct btrfs_fs_info *fs_info = dev->fs_info;
229 struct reada_zone *zone;
230 struct btrfs_block_group *cache = NULL;
236 spin_lock(&fs_info->reada_lock);
237 ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
238 logical >> PAGE_SHIFT, 1);
239 if (ret == 1 && logical >= zone->start && logical <= zone->end) {
240 kref_get(&zone->refcnt);
241 spin_unlock(&fs_info->reada_lock);
245 spin_unlock(&fs_info->reada_lock);
247 cache = btrfs_lookup_block_group(fs_info, logical);
251 start = cache->start;
252 end = start + cache->length - 1;
253 btrfs_put_block_group(cache);
255 zone = kzalloc(sizeof(*zone), GFP_KERNEL);
259 ret = radix_tree_preload(GFP_KERNEL);
267 INIT_LIST_HEAD(&zone->list);
268 spin_lock_init(&zone->lock);
270 kref_init(&zone->refcnt);
272 zone->device = dev; /* our device always sits at index 0 */
273 for (i = 0; i < bbio->num_stripes; ++i) {
274 /* bounds have already been checked */
275 zone->devs[i] = bbio->stripes[i].dev;
277 zone->ndevs = bbio->num_stripes;
279 spin_lock(&fs_info->reada_lock);
280 ret = radix_tree_insert(&dev->reada_zones,
281 (unsigned long)(zone->end >> PAGE_SHIFT),
284 if (ret == -EEXIST) {
286 ret = radix_tree_gang_lookup(&dev->reada_zones, (void **)&zone,
287 logical >> PAGE_SHIFT, 1);
288 if (ret == 1 && logical >= zone->start && logical <= zone->end)
289 kref_get(&zone->refcnt);
293 spin_unlock(&fs_info->reada_lock);
294 radix_tree_preload_end();
299 static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
301 struct btrfs_key *top)
304 struct reada_extent *re = NULL;
305 struct reada_extent *re_exist = NULL;
306 struct btrfs_bio *bbio = NULL;
307 struct btrfs_device *dev;
308 struct btrfs_device *prev_dev;
312 unsigned long index = logical >> PAGE_SHIFT;
313 int dev_replace_is_ongoing;
316 spin_lock(&fs_info->reada_lock);
317 re = radix_tree_lookup(&fs_info->reada_tree, index);
320 spin_unlock(&fs_info->reada_lock);
325 re = kzalloc(sizeof(*re), GFP_KERNEL);
329 re->logical = logical;
331 INIT_LIST_HEAD(&re->extctl);
332 spin_lock_init(&re->lock);
338 length = fs_info->nodesize;
339 ret = btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical,
341 if (ret || !bbio || length < fs_info->nodesize)
344 if (bbio->num_stripes > BTRFS_MAX_MIRRORS) {
346 "readahead: more than %d copies not supported",
351 real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
352 for (nzones = 0; nzones < real_stripes; ++nzones) {
353 struct reada_zone *zone;
355 dev = bbio->stripes[nzones].dev;
357 /* cannot read ahead on missing device. */
361 zone = reada_find_zone(dev, logical, bbio);
365 re->zones[re->nzones++] = zone;
366 spin_lock(&zone->lock);
368 kref_get(&zone->refcnt);
370 spin_unlock(&zone->lock);
371 spin_lock(&fs_info->reada_lock);
372 kref_put(&zone->refcnt, reada_zone_release);
373 spin_unlock(&fs_info->reada_lock);
375 if (re->nzones == 0) {
376 /* not a single zone found, error and out */
380 /* Insert extent in reada tree + all per-device trees, all or nothing */
381 down_read(&fs_info->dev_replace.rwsem);
382 ret = radix_tree_preload(GFP_KERNEL);
384 up_read(&fs_info->dev_replace.rwsem);
388 spin_lock(&fs_info->reada_lock);
389 ret = radix_tree_insert(&fs_info->reada_tree, index, re);
390 if (ret == -EEXIST) {
391 re_exist = radix_tree_lookup(&fs_info->reada_tree, index);
393 spin_unlock(&fs_info->reada_lock);
394 radix_tree_preload_end();
395 up_read(&fs_info->dev_replace.rwsem);
399 spin_unlock(&fs_info->reada_lock);
400 radix_tree_preload_end();
401 up_read(&fs_info->dev_replace.rwsem);
404 radix_tree_preload_end();
406 dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(
407 &fs_info->dev_replace);
408 for (nzones = 0; nzones < re->nzones; ++nzones) {
409 dev = re->zones[nzones]->device;
411 if (dev == prev_dev) {
413 * in case of DUP, just add the first zone. As both
414 * are on the same device, there's nothing to gain
416 * Also, it wouldn't work, as the tree is per device
417 * and adding would fail with EEXIST
424 if (dev_replace_is_ongoing &&
425 dev == fs_info->dev_replace.tgtdev) {
427 * as this device is selected for reading only as
428 * a last resort, skip it for read ahead.
433 ret = radix_tree_insert(&dev->reada_extents, index, re);
435 while (--nzones >= 0) {
436 dev = re->zones[nzones]->device;
438 /* ignore whether the entry was inserted */
439 radix_tree_delete(&dev->reada_extents, index);
441 radix_tree_delete(&fs_info->reada_tree, index);
442 spin_unlock(&fs_info->reada_lock);
443 up_read(&fs_info->dev_replace.rwsem);
449 radix_tree_delete(&fs_info->reada_tree, index);
450 spin_unlock(&fs_info->reada_lock);
451 up_read(&fs_info->dev_replace.rwsem);
456 btrfs_put_bbio(bbio);
460 for (nzones = 0; nzones < re->nzones; ++nzones) {
461 struct reada_zone *zone;
463 zone = re->zones[nzones];
464 kref_get(&zone->refcnt);
465 spin_lock(&zone->lock);
467 if (zone->elems == 0) {
469 * no fs_info->reada_lock needed, as this can't be
472 kref_put(&zone->refcnt, reada_zone_release);
474 spin_unlock(&zone->lock);
476 spin_lock(&fs_info->reada_lock);
477 kref_put(&zone->refcnt, reada_zone_release);
478 spin_unlock(&fs_info->reada_lock);
480 btrfs_put_bbio(bbio);
485 static void reada_extent_put(struct btrfs_fs_info *fs_info,
486 struct reada_extent *re)
489 unsigned long index = re->logical >> PAGE_SHIFT;
491 spin_lock(&fs_info->reada_lock);
493 spin_unlock(&fs_info->reada_lock);
497 radix_tree_delete(&fs_info->reada_tree, index);
498 for (i = 0; i < re->nzones; ++i) {
499 struct reada_zone *zone = re->zones[i];
501 radix_tree_delete(&zone->device->reada_extents, index);
504 spin_unlock(&fs_info->reada_lock);
506 for (i = 0; i < re->nzones; ++i) {
507 struct reada_zone *zone = re->zones[i];
509 kref_get(&zone->refcnt);
510 spin_lock(&zone->lock);
512 if (zone->elems == 0) {
513 /* no fs_info->reada_lock needed, as this can't be
515 kref_put(&zone->refcnt, reada_zone_release);
517 spin_unlock(&zone->lock);
519 spin_lock(&fs_info->reada_lock);
520 kref_put(&zone->refcnt, reada_zone_release);
521 spin_unlock(&fs_info->reada_lock);
527 static void reada_zone_release(struct kref *kref)
529 struct reada_zone *zone = container_of(kref, struct reada_zone, refcnt);
531 radix_tree_delete(&zone->device->reada_zones,
532 zone->end >> PAGE_SHIFT);
537 static void reada_control_release(struct kref *kref)
539 struct reada_control *rc = container_of(kref, struct reada_control,
545 static int reada_add_block(struct reada_control *rc, u64 logical,
546 struct btrfs_key *top, u64 generation)
548 struct btrfs_fs_info *fs_info = rc->fs_info;
549 struct reada_extent *re;
550 struct reada_extctl *rec;
553 re = reada_find_extent(fs_info, logical, top);
557 rec = kzalloc(sizeof(*rec), GFP_KERNEL);
559 reada_extent_put(fs_info, re);
564 rec->generation = generation;
565 atomic_inc(&rc->elems);
567 spin_lock(&re->lock);
568 list_add_tail(&rec->list, &re->extctl);
569 spin_unlock(&re->lock);
571 /* leave the ref on the extent */
577 * called with fs_info->reada_lock held
579 static void reada_peer_zones_set_lock(struct reada_zone *zone, int lock)
582 unsigned long index = zone->end >> PAGE_SHIFT;
584 for (i = 0; i < zone->ndevs; ++i) {
585 struct reada_zone *peer;
586 peer = radix_tree_lookup(&zone->devs[i]->reada_zones, index);
587 if (peer && peer->device != zone->device)
593 * called with fs_info->reada_lock held
595 static int reada_pick_zone(struct btrfs_device *dev)
597 struct reada_zone *top_zone = NULL;
598 struct reada_zone *top_locked_zone = NULL;
600 u64 top_locked_elems = 0;
601 unsigned long index = 0;
604 if (dev->reada_curr_zone) {
605 reada_peer_zones_set_lock(dev->reada_curr_zone, 0);
606 kref_put(&dev->reada_curr_zone->refcnt, reada_zone_release);
607 dev->reada_curr_zone = NULL;
609 /* pick the zone with the most elements */
611 struct reada_zone *zone;
613 ret = radix_tree_gang_lookup(&dev->reada_zones,
614 (void **)&zone, index, 1);
617 index = (zone->end >> PAGE_SHIFT) + 1;
619 if (zone->elems > top_locked_elems) {
620 top_locked_elems = zone->elems;
621 top_locked_zone = zone;
624 if (zone->elems > top_elems) {
625 top_elems = zone->elems;
631 dev->reada_curr_zone = top_zone;
632 else if (top_locked_zone)
633 dev->reada_curr_zone = top_locked_zone;
637 dev->reada_next = dev->reada_curr_zone->start;
638 kref_get(&dev->reada_curr_zone->refcnt);
639 reada_peer_zones_set_lock(dev->reada_curr_zone, 1);
644 static int reada_tree_block_flagged(struct btrfs_fs_info *fs_info, u64 bytenr,
645 int mirror_num, struct extent_buffer **eb)
647 struct extent_buffer *buf = NULL;
650 buf = btrfs_find_create_tree_block(fs_info, bytenr);
654 set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
656 ret = read_extent_buffer_pages(buf, WAIT_PAGE_LOCK, mirror_num);
658 free_extent_buffer_stale(buf);
662 if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
663 free_extent_buffer_stale(buf);
665 } else if (extent_buffer_uptodate(buf)) {
668 free_extent_buffer(buf);
673 static int reada_start_machine_dev(struct btrfs_device *dev)
675 struct btrfs_fs_info *fs_info = dev->fs_info;
676 struct reada_extent *re = NULL;
678 struct extent_buffer *eb = NULL;
683 spin_lock(&fs_info->reada_lock);
684 if (dev->reada_curr_zone == NULL) {
685 ret = reada_pick_zone(dev);
687 spin_unlock(&fs_info->reada_lock);
692 * FIXME currently we issue the reads one extent at a time. If we have
693 * a contiguous block of extents, we could also coagulate them or use
694 * plugging to speed things up
696 ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
697 dev->reada_next >> PAGE_SHIFT, 1);
698 if (ret == 0 || re->logical > dev->reada_curr_zone->end) {
699 ret = reada_pick_zone(dev);
701 spin_unlock(&fs_info->reada_lock);
705 ret = radix_tree_gang_lookup(&dev->reada_extents, (void **)&re,
706 dev->reada_next >> PAGE_SHIFT, 1);
709 spin_unlock(&fs_info->reada_lock);
712 dev->reada_next = re->logical + fs_info->nodesize;
715 spin_unlock(&fs_info->reada_lock);
717 spin_lock(&re->lock);
718 if (re->scheduled || list_empty(&re->extctl)) {
719 spin_unlock(&re->lock);
720 reada_extent_put(fs_info, re);
724 spin_unlock(&re->lock);
729 for (i = 0; i < re->nzones; ++i) {
730 if (re->zones[i]->device == dev) {
735 logical = re->logical;
737 atomic_inc(&dev->reada_in_flight);
738 ret = reada_tree_block_flagged(fs_info, logical, mirror_num, &eb);
740 __readahead_hook(fs_info, re, NULL, ret);
742 __readahead_hook(fs_info, re, eb, ret);
745 free_extent_buffer(eb);
747 atomic_dec(&dev->reada_in_flight);
748 reada_extent_put(fs_info, re);
754 static void reada_start_machine_worker(struct btrfs_work *work)
756 struct reada_machine_work *rmw;
759 rmw = container_of(work, struct reada_machine_work, work);
761 old_ioprio = IOPRIO_PRIO_VALUE(task_nice_ioclass(current),
762 task_nice_ioprio(current));
763 set_task_ioprio(current, BTRFS_IOPRIO_READA);
764 __reada_start_machine(rmw->fs_info);
765 set_task_ioprio(current, old_ioprio);
767 atomic_dec(&rmw->fs_info->reada_works_cnt);
772 /* Try to start up to 10k READA requests for a group of devices */
773 static int reada_start_for_fsdevs(struct btrfs_fs_devices *fs_devices)
777 struct btrfs_device *device;
781 list_for_each_entry(device, &fs_devices->devices, dev_list) {
782 if (atomic_read(&device->reada_in_flight) <
784 enqueued += reada_start_machine_dev(device);
787 } while (enqueued && total < 10000);
792 static void __reada_start_machine(struct btrfs_fs_info *fs_info)
794 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices, *seed_devs;
798 mutex_lock(&fs_devices->device_list_mutex);
800 enqueued += reada_start_for_fsdevs(fs_devices);
801 list_for_each_entry(seed_devs, &fs_devices->seed_list, seed_list)
802 enqueued += reada_start_for_fsdevs(seed_devs);
804 mutex_unlock(&fs_devices->device_list_mutex);
809 * If everything is already in the cache, this is effectively single
810 * threaded. To a) not hold the caller for too long and b) to utilize
811 * more cores, we broke the loop above after 10000 iterations and now
812 * enqueue to workers to finish it. This will distribute the load to
815 for (i = 0; i < 2; ++i) {
816 reada_start_machine(fs_info);
817 if (atomic_read(&fs_info->reada_works_cnt) >
818 BTRFS_MAX_MIRRORS * 2)
823 static void reada_start_machine(struct btrfs_fs_info *fs_info)
825 struct reada_machine_work *rmw;
827 rmw = kzalloc(sizeof(*rmw), GFP_KERNEL);
829 /* FIXME we cannot handle this properly right now */
832 btrfs_init_work(&rmw->work, reada_start_machine_worker, NULL, NULL);
833 rmw->fs_info = fs_info;
835 btrfs_queue_work(fs_info->readahead_workers, &rmw->work);
836 atomic_inc(&fs_info->reada_works_cnt);
840 static void dump_devs(struct btrfs_fs_info *fs_info, int all)
842 struct btrfs_device *device;
843 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
850 spin_lock(&fs_info->reada_lock);
851 list_for_each_entry(device, &fs_devices->devices, dev_list) {
852 btrfs_debug(fs_info, "dev %lld has %d in flight", device->devid,
853 atomic_read(&device->reada_in_flight));
856 struct reada_zone *zone;
857 ret = radix_tree_gang_lookup(&device->reada_zones,
858 (void **)&zone, index, 1);
861 pr_debug(" zone %llu-%llu elems %llu locked %d devs",
862 zone->start, zone->end, zone->elems,
864 for (j = 0; j < zone->ndevs; ++j) {
866 zone->devs[j]->devid);
868 if (device->reada_curr_zone == zone)
869 pr_cont(" curr off %llu",
870 device->reada_next - zone->start);
872 index = (zone->end >> PAGE_SHIFT) + 1;
877 struct reada_extent *re = NULL;
879 ret = radix_tree_gang_lookup(&device->reada_extents,
880 (void **)&re, index, 1);
883 pr_debug(" re: logical %llu size %u empty %d scheduled %d",
884 re->logical, fs_info->nodesize,
885 list_empty(&re->extctl), re->scheduled);
887 for (i = 0; i < re->nzones; ++i) {
888 pr_cont(" zone %llu-%llu devs",
891 for (j = 0; j < re->zones[i]->ndevs; ++j) {
893 re->zones[i]->devs[j]->devid);
897 index = (re->logical >> PAGE_SHIFT) + 1;
906 struct reada_extent *re = NULL;
908 ret = radix_tree_gang_lookup(&fs_info->reada_tree, (void **)&re,
912 if (!re->scheduled) {
913 index = (re->logical >> PAGE_SHIFT) + 1;
916 pr_debug("re: logical %llu size %u list empty %d scheduled %d",
917 re->logical, fs_info->nodesize,
918 list_empty(&re->extctl), re->scheduled);
919 for (i = 0; i < re->nzones; ++i) {
920 pr_cont(" zone %llu-%llu devs",
923 for (j = 0; j < re->zones[i]->ndevs; ++j) {
925 re->zones[i]->devs[j]->devid);
929 index = (re->logical >> PAGE_SHIFT) + 1;
931 spin_unlock(&fs_info->reada_lock);
938 struct reada_control *btrfs_reada_add(struct btrfs_root *root,
939 struct btrfs_key *key_start, struct btrfs_key *key_end)
941 struct reada_control *rc;
945 struct extent_buffer *node;
946 static struct btrfs_key max_key = {
952 rc = kzalloc(sizeof(*rc), GFP_KERNEL);
954 return ERR_PTR(-ENOMEM);
956 rc->fs_info = root->fs_info;
957 rc->key_start = *key_start;
958 rc->key_end = *key_end;
959 atomic_set(&rc->elems, 0);
960 init_waitqueue_head(&rc->wait);
961 kref_init(&rc->refcnt);
962 kref_get(&rc->refcnt); /* one ref for having elements */
964 node = btrfs_root_node(root);
966 generation = btrfs_header_generation(node);
967 free_extent_buffer(node);
969 ret = reada_add_block(rc, start, &max_key, generation);
975 reada_start_machine(root->fs_info);
981 int btrfs_reada_wait(void *handle)
983 struct reada_control *rc = handle;
984 struct btrfs_fs_info *fs_info = rc->fs_info;
986 while (atomic_read(&rc->elems)) {
987 if (!atomic_read(&fs_info->reada_works_cnt))
988 reada_start_machine(fs_info);
989 wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
991 dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0);
994 dump_devs(fs_info, atomic_read(&rc->elems) < 10 ? 1 : 0);
996 kref_put(&rc->refcnt, reada_control_release);
1001 int btrfs_reada_wait(void *handle)
1003 struct reada_control *rc = handle;
1004 struct btrfs_fs_info *fs_info = rc->fs_info;
1006 while (atomic_read(&rc->elems)) {
1007 if (!atomic_read(&fs_info->reada_works_cnt))
1008 reada_start_machine(fs_info);
1009 wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0,
1013 kref_put(&rc->refcnt, reada_control_release);
1019 void btrfs_reada_detach(void *handle)
1021 struct reada_control *rc = handle;
1023 kref_put(&rc->refcnt, reada_control_release);