1 // SPDX-License-Identifier: GPL-2.0
5 #include "space-info.h"
8 #include "free-space-cache.h"
9 #include "ordered-data.h"
10 #include "transaction.h"
11 #include "block-group.h"
14 #include "accessors.h"
15 #include "extent-tree.h"
18 * HOW DOES SPACE RESERVATION WORK
20 * If you want to know about delalloc specifically, there is a separate comment
21 * for that with the delalloc code. This comment is about how the whole system
26 * 1) space_info. This is the ultimate arbiter of how much space we can use.
27 * There's a description of the bytes_ fields with the struct declaration,
28 * refer to that for specifics on each field. Suffice it to say that for
29 * reservations we care about total_bytes - SUM(space_info->bytes_) when
30 * determining if there is space to make an allocation. There is a space_info
31 * for METADATA, SYSTEM, and DATA areas.
33 * 2) block_rsv's. These are basically buckets for every different type of
34 * metadata reservation we have. You can see the comment in the block_rsv
35 * code on the rules for each type, but generally block_rsv->reserved is how
36 * much space is accounted for in space_info->bytes_may_use.
38 * 3) btrfs_calc*_size. These are the worst case calculations we used based
39 * on the number of items we will want to modify. We have one for changing
40 * items, and one for inserting new items. Generally we use these helpers to
41 * determine the size of the block reserves, and then use the actual bytes
42 * values to adjust the space_info counters.
44 * MAKING RESERVATIONS, THE NORMAL CASE
46 * We call into either btrfs_reserve_data_bytes() or
47 * btrfs_reserve_metadata_bytes(), depending on which we're looking for, with
48 * num_bytes we want to reserve.
51 * space_info->bytes_may_reserve += num_bytes
54 * Call btrfs_add_reserved_bytes() which does
55 * space_info->bytes_may_reserve -= num_bytes
56 * space_info->bytes_reserved += extent_bytes
59 * Call btrfs_update_block_group() which does
60 * space_info->bytes_reserved -= extent_bytes
61 * space_info->bytes_used += extent_bytes
63 * MAKING RESERVATIONS, FLUSHING NORMALLY (non-priority)
65 * Assume we are unable to simply make the reservation because we do not have
69 * create a reserve_ticket with ->bytes set to our reservation, add it to
70 * the tail of space_info->tickets, kick async flush thread
72 * ->handle_reserve_ticket
73 * wait on ticket->wait for ->bytes to be reduced to 0, or ->error to be set
76 * -> btrfs_async_reclaim_metadata_space/btrfs_async_reclaim_data_space
77 * Flushes various things attempting to free up space.
79 * -> btrfs_try_granting_tickets()
80 * This is called by anything that either subtracts space from
81 * space_info->bytes_may_use, ->bytes_pinned, etc, or adds to the
82 * space_info->total_bytes. This loops through the ->priority_tickets and
83 * then the ->tickets list checking to see if the reservation can be
84 * completed. If it can the space is added to space_info->bytes_may_use and
85 * the ticket is woken up.
88 * Check if ->bytes == 0, if it does we got our reservation and we can carry
89 * on, if not return the appropriate error (ENOSPC, but can be EINTR if we
92 * MAKING RESERVATIONS, FLUSHING HIGH PRIORITY
94 * Same as the above, except we add ourselves to the
95 * space_info->priority_tickets, and we do not use ticket->wait, we simply
96 * call flush_space() ourselves for the states that are safe for us to call
97 * without deadlocking and hope for the best.
101 * Generally speaking we will have two cases for each state, a "nice" state
102 * and a "ALL THE THINGS" state. In btrfs we delay a lot of work in order to
103 * reduce the locking over head on the various trees, and even to keep from
104 * doing any work at all in the case of delayed refs. Each of these delayed
105 * things however hold reservations, and so letting them run allows us to
106 * reclaim space so we can make new reservations.
108 * FLUSH_DELAYED_ITEMS
109 * Every inode has a delayed item to update the inode. Take a simple write
110 * for example, we would update the inode item at write time to update the
111 * mtime, and then again at finish_ordered_io() time in order to update the
112 * isize or bytes. We keep these delayed items to coalesce these operations
113 * into a single operation done on demand. These are an easy way to reclaim
117 * Look at the delalloc comment to get an idea of how much space is reserved
118 * for delayed allocation. We can reclaim some of this space simply by
119 * running delalloc, but usually we need to wait for ordered extents to
120 * reclaim the bulk of this space.
123 * We have a block reserve for the outstanding delayed refs space, and every
124 * delayed ref operation holds a reservation. Running these is a quick way
125 * to reclaim space, but we want to hold this until the end because COW can
126 * churn a lot and we can avoid making some extent tree modifications if we
127 * are able to delay for as long as possible.
130 * We will skip this the first time through space reservation, because of
131 * overcommit and we don't want to have a lot of useless metadata space when
132 * our worst case reservations will likely never come true.
135 * If we're freeing inodes we're likely freeing checksums, file extent
136 * items, and extent tree items. Loads of space could be freed up by these
137 * operations, however they won't be usable until the transaction commits.
140 * This will commit the transaction. Historically we had a lot of logic
141 * surrounding whether or not we'd commit the transaction, but this waits born
142 * out of a pre-tickets era where we could end up committing the transaction
143 * thousands of times in a row without making progress. Now thanks to our
144 * ticketing system we know if we're not making progress and can error
145 * everybody out after a few commits rather than burning the disk hoping for
146 * a different answer.
150 * Because we hold so many reservations for metadata we will allow you to
151 * reserve more space than is currently free in the currently allocate
152 * metadata space. This only happens with metadata, data does not allow
155 * You can see the current logic for when we allow overcommit in
156 * btrfs_can_overcommit(), but it only applies to unallocated space. If there
157 * is no unallocated space to be had, all reservations are kept within the
158 * free space in the allocated metadata chunks.
160 * Because of overcommitting, you generally want to use the
161 * btrfs_can_overcommit() logic for metadata allocations, as it does the right
162 * thing with or without extra unallocated space.
165 u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info,
166 bool may_use_included)
169 return s_info->bytes_used + s_info->bytes_reserved +
170 s_info->bytes_pinned + s_info->bytes_readonly +
171 s_info->bytes_zone_unusable +
172 (may_use_included ? s_info->bytes_may_use : 0);
176 * after adding space to the filesystem, we need to clear the full flags
177 * on all the space infos.
179 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
181 struct list_head *head = &info->space_info;
182 struct btrfs_space_info *found;
184 list_for_each_entry(found, head, list)
189 * Block groups with more than this value (percents) of unusable space will be
190 * scheduled for background reclaim.
192 #define BTRFS_DEFAULT_ZONED_RECLAIM_THRESH (75)
195 * Calculate chunk size depending on volume type (regular or zoned).
197 static u64 calc_chunk_size(const struct btrfs_fs_info *fs_info, u64 flags)
199 if (btrfs_is_zoned(fs_info))
200 return fs_info->zone_size;
202 ASSERT(flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
204 if (flags & BTRFS_BLOCK_GROUP_DATA)
205 return BTRFS_MAX_DATA_CHUNK_SIZE;
206 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
209 /* Handle BTRFS_BLOCK_GROUP_METADATA */
210 if (fs_info->fs_devices->total_rw_bytes > 50ULL * SZ_1G)
217 * Update default chunk size.
219 void btrfs_update_space_info_chunk_size(struct btrfs_space_info *space_info,
222 WRITE_ONCE(space_info->chunk_size, chunk_size);
225 static int create_space_info(struct btrfs_fs_info *info, u64 flags)
228 struct btrfs_space_info *space_info;
232 space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
236 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
237 INIT_LIST_HEAD(&space_info->block_groups[i]);
238 init_rwsem(&space_info->groups_sem);
239 spin_lock_init(&space_info->lock);
240 space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
241 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
242 INIT_LIST_HEAD(&space_info->ro_bgs);
243 INIT_LIST_HEAD(&space_info->tickets);
244 INIT_LIST_HEAD(&space_info->priority_tickets);
245 space_info->clamp = 1;
246 btrfs_update_space_info_chunk_size(space_info, calc_chunk_size(info, flags));
248 if (btrfs_is_zoned(info))
249 space_info->bg_reclaim_threshold = BTRFS_DEFAULT_ZONED_RECLAIM_THRESH;
251 ret = btrfs_sysfs_add_space_info_type(info, space_info);
255 list_add(&space_info->list, &info->space_info);
256 if (flags & BTRFS_BLOCK_GROUP_DATA)
257 info->data_sinfo = space_info;
262 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
264 struct btrfs_super_block *disk_super;
270 disk_super = fs_info->super_copy;
271 if (!btrfs_super_root(disk_super))
274 features = btrfs_super_incompat_flags(disk_super);
275 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
278 flags = BTRFS_BLOCK_GROUP_SYSTEM;
279 ret = create_space_info(fs_info, flags);
284 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
285 ret = create_space_info(fs_info, flags);
287 flags = BTRFS_BLOCK_GROUP_METADATA;
288 ret = create_space_info(fs_info, flags);
292 flags = BTRFS_BLOCK_GROUP_DATA;
293 ret = create_space_info(fs_info, flags);
299 void btrfs_add_bg_to_space_info(struct btrfs_fs_info *info,
300 struct btrfs_block_group *block_group)
302 struct btrfs_space_info *found;
305 factor = btrfs_bg_type_to_factor(block_group->flags);
307 found = btrfs_find_space_info(info, block_group->flags);
309 spin_lock(&found->lock);
310 found->total_bytes += block_group->length;
311 if (test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE, &block_group->runtime_flags))
312 found->active_total_bytes += block_group->length;
313 found->disk_total += block_group->length * factor;
314 found->bytes_used += block_group->used;
315 found->disk_used += block_group->used * factor;
316 found->bytes_readonly += block_group->bytes_super;
317 found->bytes_zone_unusable += block_group->zone_unusable;
318 if (block_group->length > 0)
320 btrfs_try_granting_tickets(info, found);
321 spin_unlock(&found->lock);
323 block_group->space_info = found;
325 index = btrfs_bg_flags_to_raid_index(block_group->flags);
326 down_write(&found->groups_sem);
327 list_add_tail(&block_group->list, &found->block_groups[index]);
328 up_write(&found->groups_sem);
331 struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
334 struct list_head *head = &info->space_info;
335 struct btrfs_space_info *found;
337 flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
339 list_for_each_entry(found, head, list) {
340 if (found->flags & flags)
346 static u64 calc_available_free_space(struct btrfs_fs_info *fs_info,
347 struct btrfs_space_info *space_info,
348 enum btrfs_reserve_flush_enum flush)
354 if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM)
355 profile = btrfs_system_alloc_profile(fs_info);
357 profile = btrfs_metadata_alloc_profile(fs_info);
359 avail = atomic64_read(&fs_info->free_chunk_space);
362 * If we have dup, raid1 or raid10 then only half of the free
363 * space is actually usable. For raid56, the space info used
364 * doesn't include the parity drive, so we don't have to
367 factor = btrfs_bg_type_to_factor(profile);
368 avail = div_u64(avail, factor);
371 * If we aren't flushing all things, let us overcommit up to
372 * 1/2th of the space. If we can flush, don't let us overcommit
373 * too much, let it overcommit up to 1/8 of the space.
375 if (flush == BTRFS_RESERVE_FLUSH_ALL)
382 static inline u64 writable_total_bytes(struct btrfs_fs_info *fs_info,
383 struct btrfs_space_info *space_info)
386 * On regular filesystem, all total_bytes are always writable. On zoned
387 * filesystem, there may be a limitation imposed by max_active_zones.
388 * For metadata allocation, we cannot finish an existing active block
389 * group to avoid a deadlock. Thus, we need to consider only the active
390 * groups to be writable for metadata space.
392 if (!btrfs_is_zoned(fs_info) || (space_info->flags & BTRFS_BLOCK_GROUP_DATA))
393 return space_info->total_bytes;
395 return space_info->active_total_bytes;
398 int btrfs_can_overcommit(struct btrfs_fs_info *fs_info,
399 struct btrfs_space_info *space_info, u64 bytes,
400 enum btrfs_reserve_flush_enum flush)
405 /* Don't overcommit when in mixed mode */
406 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
409 used = btrfs_space_info_used(space_info, true);
410 if (btrfs_is_zoned(fs_info) && (space_info->flags & BTRFS_BLOCK_GROUP_METADATA))
413 avail = calc_available_free_space(fs_info, space_info, flush);
415 if (used + bytes < writable_total_bytes(fs_info, space_info) + avail)
420 static void remove_ticket(struct btrfs_space_info *space_info,
421 struct reserve_ticket *ticket)
423 if (!list_empty(&ticket->list)) {
424 list_del_init(&ticket->list);
425 ASSERT(space_info->reclaim_size >= ticket->bytes);
426 space_info->reclaim_size -= ticket->bytes;
431 * This is for space we already have accounted in space_info->bytes_may_use, so
432 * basically when we're returning space from block_rsv's.
434 void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
435 struct btrfs_space_info *space_info)
437 struct list_head *head;
438 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
440 lockdep_assert_held(&space_info->lock);
442 head = &space_info->priority_tickets;
444 while (!list_empty(head)) {
445 struct reserve_ticket *ticket;
446 u64 used = btrfs_space_info_used(space_info, true);
448 ticket = list_first_entry(head, struct reserve_ticket, list);
450 /* Check and see if our ticket can be satisfied now. */
451 if ((used + ticket->bytes <= writable_total_bytes(fs_info, space_info)) ||
452 btrfs_can_overcommit(fs_info, space_info, ticket->bytes,
454 btrfs_space_info_update_bytes_may_use(fs_info,
457 remove_ticket(space_info, ticket);
459 space_info->tickets_id++;
460 wake_up(&ticket->wait);
466 if (head == &space_info->priority_tickets) {
467 head = &space_info->tickets;
468 flush = BTRFS_RESERVE_FLUSH_ALL;
473 #define DUMP_BLOCK_RSV(fs_info, rsv_name) \
475 struct btrfs_block_rsv *__rsv = &(fs_info)->rsv_name; \
476 spin_lock(&__rsv->lock); \
477 btrfs_info(fs_info, #rsv_name ": size %llu reserved %llu", \
478 __rsv->size, __rsv->reserved); \
479 spin_unlock(&__rsv->lock); \
482 static const char *space_info_flag_to_str(const struct btrfs_space_info *space_info)
484 switch (space_info->flags) {
485 case BTRFS_BLOCK_GROUP_SYSTEM:
487 case BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA:
488 return "DATA+METADATA";
489 case BTRFS_BLOCK_GROUP_DATA:
491 case BTRFS_BLOCK_GROUP_METADATA:
498 static void dump_global_block_rsv(struct btrfs_fs_info *fs_info)
500 DUMP_BLOCK_RSV(fs_info, global_block_rsv);
501 DUMP_BLOCK_RSV(fs_info, trans_block_rsv);
502 DUMP_BLOCK_RSV(fs_info, chunk_block_rsv);
503 DUMP_BLOCK_RSV(fs_info, delayed_block_rsv);
504 DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv);
507 static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
508 struct btrfs_space_info *info)
510 const char *flag_str = space_info_flag_to_str(info);
511 lockdep_assert_held(&info->lock);
513 /* The free space could be negative in case of overcommit */
514 btrfs_info(fs_info, "space_info %s has %lld free, is %sfull",
516 (s64)(info->total_bytes - btrfs_space_info_used(info, true)),
517 info->full ? "" : "not ");
519 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu zone_unusable=%llu",
520 info->total_bytes, info->bytes_used, info->bytes_pinned,
521 info->bytes_reserved, info->bytes_may_use,
522 info->bytes_readonly, info->bytes_zone_unusable);
525 void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
526 struct btrfs_space_info *info, u64 bytes,
527 int dump_block_groups)
529 struct btrfs_block_group *cache;
532 spin_lock(&info->lock);
533 __btrfs_dump_space_info(fs_info, info);
534 dump_global_block_rsv(fs_info);
535 spin_unlock(&info->lock);
537 if (!dump_block_groups)
540 down_read(&info->groups_sem);
542 list_for_each_entry(cache, &info->block_groups[index], list) {
543 spin_lock(&cache->lock);
545 "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %llu zone_unusable %s",
546 cache->start, cache->length, cache->used, cache->pinned,
547 cache->reserved, cache->zone_unusable,
548 cache->ro ? "[readonly]" : "");
549 spin_unlock(&cache->lock);
550 btrfs_dump_free_space(cache, bytes);
552 if (++index < BTRFS_NR_RAID_TYPES)
554 up_read(&info->groups_sem);
557 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
563 bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
564 nr = div64_u64(to_reclaim, bytes);
570 #define EXTENT_SIZE_PER_ITEM SZ_256K
573 * shrink metadata reservation for delalloc
575 static void shrink_delalloc(struct btrfs_fs_info *fs_info,
576 struct btrfs_space_info *space_info,
577 u64 to_reclaim, bool wait_ordered,
580 struct btrfs_trans_handle *trans;
587 delalloc_bytes = percpu_counter_sum_positive(&fs_info->delalloc_bytes);
588 ordered_bytes = percpu_counter_sum_positive(&fs_info->ordered_bytes);
589 if (delalloc_bytes == 0 && ordered_bytes == 0)
592 /* Calc the number of the pages we need flush for space reservation */
593 if (to_reclaim == U64_MAX) {
597 * to_reclaim is set to however much metadata we need to
598 * reclaim, but reclaiming that much data doesn't really track
599 * exactly. What we really want to do is reclaim full inode's
600 * worth of reservations, however that's not available to us
601 * here. We will take a fraction of the delalloc bytes for our
602 * flushing loops and hope for the best. Delalloc will expand
603 * the amount we write to cover an entire dirty extent, which
604 * will reclaim the metadata reservation for that range. If
605 * it's not enough subsequent flush stages will be more
608 to_reclaim = max(to_reclaim, delalloc_bytes >> 3);
609 items = calc_reclaim_items_nr(fs_info, to_reclaim) * 2;
612 trans = current->journal_info;
615 * If we are doing more ordered than delalloc we need to just wait on
616 * ordered extents, otherwise we'll waste time trying to flush delalloc
617 * that likely won't give us the space back we need.
619 if (ordered_bytes > delalloc_bytes && !for_preempt)
623 while ((delalloc_bytes || ordered_bytes) && loops < 3) {
624 u64 temp = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT;
625 long nr_pages = min_t(u64, temp, LONG_MAX);
628 btrfs_start_delalloc_roots(fs_info, nr_pages, true);
631 * We need to make sure any outstanding async pages are now
632 * processed before we continue. This is because things like
633 * sync_inode() try to be smart and skip writing if the inode is
634 * marked clean. We don't use filemap_fwrite for flushing
635 * because we want to control how many pages we write out at a
636 * time, thus this is the only safe way to make sure we've
637 * waited for outstanding compressed workers to have started
638 * their jobs and thus have ordered extents set up properly.
640 * This exists because we do not want to wait for each
641 * individual inode to finish its async work, we simply want to
642 * start the IO on everybody, and then come back here and wait
643 * for all of the async work to catch up. Once we're done with
644 * that we know we'll have ordered extents for everything and we
645 * can decide if we wait for that or not.
647 * If we choose to replace this in the future, make absolutely
648 * sure that the proper waiting is being done in the async case,
649 * as there have been bugs in that area before.
651 async_pages = atomic_read(&fs_info->async_delalloc_pages);
656 * We don't want to wait forever, if we wrote less pages in this
657 * loop than we have outstanding, only wait for that number of
658 * pages, otherwise we can wait for all async pages to finish
661 if (async_pages > nr_pages)
662 async_pages -= nr_pages;
665 wait_event(fs_info->async_submit_wait,
666 atomic_read(&fs_info->async_delalloc_pages) <=
670 if (wait_ordered && !trans) {
671 btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
673 time_left = schedule_timeout_killable(1);
679 * If we are for preemption we just want a one-shot of delalloc
680 * flushing so we can stop flushing if we decide we don't need
686 spin_lock(&space_info->lock);
687 if (list_empty(&space_info->tickets) &&
688 list_empty(&space_info->priority_tickets)) {
689 spin_unlock(&space_info->lock);
692 spin_unlock(&space_info->lock);
694 delalloc_bytes = percpu_counter_sum_positive(
695 &fs_info->delalloc_bytes);
696 ordered_bytes = percpu_counter_sum_positive(
697 &fs_info->ordered_bytes);
702 * Try to flush some data based on policy set by @state. This is only advisory
703 * and may fail for various reasons. The caller is supposed to examine the
704 * state of @space_info to detect the outcome.
706 static void flush_space(struct btrfs_fs_info *fs_info,
707 struct btrfs_space_info *space_info, u64 num_bytes,
708 enum btrfs_flush_state state, bool for_preempt)
710 struct btrfs_root *root = fs_info->tree_root;
711 struct btrfs_trans_handle *trans;
716 case FLUSH_DELAYED_ITEMS_NR:
717 case FLUSH_DELAYED_ITEMS:
718 if (state == FLUSH_DELAYED_ITEMS_NR)
719 nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
723 trans = btrfs_join_transaction(root);
725 ret = PTR_ERR(trans);
728 ret = btrfs_run_delayed_items_nr(trans, nr);
729 btrfs_end_transaction(trans);
732 case FLUSH_DELALLOC_WAIT:
733 case FLUSH_DELALLOC_FULL:
734 if (state == FLUSH_DELALLOC_FULL)
736 shrink_delalloc(fs_info, space_info, num_bytes,
737 state != FLUSH_DELALLOC, for_preempt);
739 case FLUSH_DELAYED_REFS_NR:
740 case FLUSH_DELAYED_REFS:
741 trans = btrfs_join_transaction(root);
743 ret = PTR_ERR(trans);
746 if (state == FLUSH_DELAYED_REFS_NR)
747 nr = calc_reclaim_items_nr(fs_info, num_bytes);
750 btrfs_run_delayed_refs(trans, nr);
751 btrfs_end_transaction(trans);
754 case ALLOC_CHUNK_FORCE:
756 * For metadata space on zoned filesystem, reaching here means we
757 * don't have enough space left in active_total_bytes. Try to
758 * activate a block group first, because we may have inactive
759 * block group already allocated.
761 ret = btrfs_zoned_activate_one_bg(fs_info, space_info, false);
767 trans = btrfs_join_transaction(root);
769 ret = PTR_ERR(trans);
772 ret = btrfs_chunk_alloc(trans,
773 btrfs_get_alloc_profile(fs_info, space_info->flags),
774 (state == ALLOC_CHUNK) ? CHUNK_ALLOC_NO_FORCE :
776 btrfs_end_transaction(trans);
779 * For metadata space on zoned filesystem, allocating a new chunk
780 * is not enough. We still need to activate the block * group.
781 * Active the newly allocated block group by (maybe) finishing
785 ret = btrfs_zoned_activate_one_bg(fs_info, space_info, true);
787 * Revert to the original ret regardless we could finish
788 * one block group or not.
794 if (ret > 0 || ret == -ENOSPC)
797 case RUN_DELAYED_IPUTS:
799 * If we have pending delayed iputs then we could free up a
800 * bunch of pinned space, so make sure we run the iputs before
801 * we do our pinned bytes check below.
803 btrfs_run_delayed_iputs(fs_info);
804 btrfs_wait_on_delayed_iputs(fs_info);
807 ASSERT(current->journal_info == NULL);
808 trans = btrfs_join_transaction(root);
810 ret = PTR_ERR(trans);
813 ret = btrfs_commit_transaction(trans);
820 trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
826 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
827 struct btrfs_space_info *space_info)
832 u64 to_reclaim = space_info->reclaim_size;
834 lockdep_assert_held(&space_info->lock);
836 avail = calc_available_free_space(fs_info, space_info,
837 BTRFS_RESERVE_FLUSH_ALL);
838 used = btrfs_space_info_used(space_info, true);
841 * We may be flushing because suddenly we have less space than we had
842 * before, and now we're well over-committed based on our current free
843 * space. If that's the case add in our overage so we make sure to put
844 * appropriate pressure on the flushing state machine.
846 total = writable_total_bytes(fs_info, space_info);
847 if (total + avail < used)
848 to_reclaim += used - (total + avail);
853 static bool need_preemptive_reclaim(struct btrfs_fs_info *fs_info,
854 struct btrfs_space_info *space_info)
856 u64 global_rsv_size = fs_info->global_block_rsv.reserved;
857 u64 ordered, delalloc;
858 u64 total = writable_total_bytes(fs_info, space_info);
862 thresh = mult_perc(total, 90);
864 lockdep_assert_held(&space_info->lock);
866 /* If we're just plain full then async reclaim just slows us down. */
867 if ((space_info->bytes_used + space_info->bytes_reserved +
868 global_rsv_size) >= thresh)
871 used = space_info->bytes_may_use + space_info->bytes_pinned;
873 /* The total flushable belongs to the global rsv, don't flush. */
874 if (global_rsv_size >= used)
878 * 128MiB is 1/4 of the maximum global rsv size. If we have less than
879 * that devoted to other reservations then there's no sense in flushing,
880 * we don't have a lot of things that need flushing.
882 if (used - global_rsv_size <= SZ_128M)
886 * We have tickets queued, bail so we don't compete with the async
889 if (space_info->reclaim_size)
893 * If we have over half of the free space occupied by reservations or
894 * pinned then we want to start flushing.
896 * We do not do the traditional thing here, which is to say
898 * if (used >= ((total_bytes + avail) / 2))
901 * because this doesn't quite work how we want. If we had more than 50%
902 * of the space_info used by bytes_used and we had 0 available we'd just
903 * constantly run the background flusher. Instead we want it to kick in
904 * if our reclaimable space exceeds our clamped free space.
906 * Our clamping range is 2^1 -> 2^8. Practically speaking that means
909 * Amount of RAM Minimum threshold Maximum threshold
912 * 128GiB 512MiB 64GiB
917 * These are the range our thresholds will fall in, corresponding to how
918 * much delalloc we need for the background flusher to kick in.
921 thresh = calc_available_free_space(fs_info, space_info,
922 BTRFS_RESERVE_FLUSH_ALL);
923 used = space_info->bytes_used + space_info->bytes_reserved +
924 space_info->bytes_readonly + global_rsv_size;
926 thresh += total - used;
927 thresh >>= space_info->clamp;
929 used = space_info->bytes_pinned;
932 * If we have more ordered bytes than delalloc bytes then we're either
933 * doing a lot of DIO, or we simply don't have a lot of delalloc waiting
934 * around. Preemptive flushing is only useful in that it can free up
935 * space before tickets need to wait for things to finish. In the case
936 * of ordered extents, preemptively waiting on ordered extents gets us
937 * nothing, if our reservations are tied up in ordered extents we'll
938 * simply have to slow down writers by forcing them to wait on ordered
941 * In the case that ordered is larger than delalloc, only include the
942 * block reserves that we would actually be able to directly reclaim
943 * from. In this case if we're heavy on metadata operations this will
944 * clearly be heavy enough to warrant preemptive flushing. In the case
945 * of heavy DIO or ordered reservations, preemptive flushing will just
946 * waste time and cause us to slow down.
948 * We want to make sure we truly are maxed out on ordered however, so
949 * cut ordered in half, and if it's still higher than delalloc then we
950 * can keep flushing. This is to avoid the case where we start
951 * flushing, and now delalloc == ordered and we stop preemptively
952 * flushing when we could still have several gigs of delalloc to flush.
954 ordered = percpu_counter_read_positive(&fs_info->ordered_bytes) >> 1;
955 delalloc = percpu_counter_read_positive(&fs_info->delalloc_bytes);
956 if (ordered >= delalloc)
957 used += fs_info->delayed_refs_rsv.reserved +
958 fs_info->delayed_block_rsv.reserved;
960 used += space_info->bytes_may_use - global_rsv_size;
962 return (used >= thresh && !btrfs_fs_closing(fs_info) &&
963 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
966 static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info,
967 struct btrfs_space_info *space_info,
968 struct reserve_ticket *ticket)
970 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
976 if (global_rsv->space_info != space_info)
979 spin_lock(&global_rsv->lock);
980 min_bytes = mult_perc(global_rsv->size, 10);
981 if (global_rsv->reserved < min_bytes + ticket->bytes) {
982 spin_unlock(&global_rsv->lock);
985 global_rsv->reserved -= ticket->bytes;
986 remove_ticket(space_info, ticket);
988 wake_up(&ticket->wait);
989 space_info->tickets_id++;
990 if (global_rsv->reserved < global_rsv->size)
991 global_rsv->full = 0;
992 spin_unlock(&global_rsv->lock);
998 * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets
999 * @fs_info - fs_info for this fs
1000 * @space_info - the space info we were flushing
1002 * We call this when we've exhausted our flushing ability and haven't made
1003 * progress in satisfying tickets. The reservation code handles tickets in
1004 * order, so if there is a large ticket first and then smaller ones we could
1005 * very well satisfy the smaller tickets. This will attempt to wake up any
1006 * tickets in the list to catch this case.
1008 * This function returns true if it was able to make progress by clearing out
1009 * other tickets, or if it stumbles across a ticket that was smaller than the
1012 static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
1013 struct btrfs_space_info *space_info)
1015 struct reserve_ticket *ticket;
1016 u64 tickets_id = space_info->tickets_id;
1017 const bool aborted = BTRFS_FS_ERROR(fs_info);
1019 trace_btrfs_fail_all_tickets(fs_info, space_info);
1021 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1022 btrfs_info(fs_info, "cannot satisfy tickets, dumping space info");
1023 __btrfs_dump_space_info(fs_info, space_info);
1026 while (!list_empty(&space_info->tickets) &&
1027 tickets_id == space_info->tickets_id) {
1028 ticket = list_first_entry(&space_info->tickets,
1029 struct reserve_ticket, list);
1031 if (!aborted && steal_from_global_rsv(fs_info, space_info, ticket))
1034 if (!aborted && btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1035 btrfs_info(fs_info, "failing ticket with %llu bytes",
1038 remove_ticket(space_info, ticket);
1040 ticket->error = -EIO;
1042 ticket->error = -ENOSPC;
1043 wake_up(&ticket->wait);
1046 * We're just throwing tickets away, so more flushing may not
1047 * trip over btrfs_try_granting_tickets, so we need to call it
1048 * here to see if we can make progress with the next ticket in
1052 btrfs_try_granting_tickets(fs_info, space_info);
1054 return (tickets_id != space_info->tickets_id);
1058 * This is for normal flushers, we can wait all goddamned day if we want to. We
1059 * will loop and continuously try to flush as long as we are making progress.
1060 * We count progress as clearing off tickets each time we have to loop.
1062 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
1064 struct btrfs_fs_info *fs_info;
1065 struct btrfs_space_info *space_info;
1067 enum btrfs_flush_state flush_state;
1068 int commit_cycles = 0;
1069 u64 last_tickets_id;
1071 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
1072 space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
1074 spin_lock(&space_info->lock);
1075 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
1077 space_info->flush = 0;
1078 spin_unlock(&space_info->lock);
1081 last_tickets_id = space_info->tickets_id;
1082 spin_unlock(&space_info->lock);
1084 flush_state = FLUSH_DELAYED_ITEMS_NR;
1086 flush_space(fs_info, space_info, to_reclaim, flush_state, false);
1087 spin_lock(&space_info->lock);
1088 if (list_empty(&space_info->tickets)) {
1089 space_info->flush = 0;
1090 spin_unlock(&space_info->lock);
1093 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
1095 if (last_tickets_id == space_info->tickets_id) {
1098 last_tickets_id = space_info->tickets_id;
1099 flush_state = FLUSH_DELAYED_ITEMS_NR;
1105 * We do not want to empty the system of delalloc unless we're
1106 * under heavy pressure, so allow one trip through the flushing
1107 * logic before we start doing a FLUSH_DELALLOC_FULL.
1109 if (flush_state == FLUSH_DELALLOC_FULL && !commit_cycles)
1113 * We don't want to force a chunk allocation until we've tried
1114 * pretty hard to reclaim space. Think of the case where we
1115 * freed up a bunch of space and so have a lot of pinned space
1116 * to reclaim. We would rather use that than possibly create a
1117 * underutilized metadata chunk. So if this is our first run
1118 * through the flushing state machine skip ALLOC_CHUNK_FORCE and
1119 * commit the transaction. If nothing has changed the next go
1120 * around then we can force a chunk allocation.
1122 if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
1125 if (flush_state > COMMIT_TRANS) {
1127 if (commit_cycles > 2) {
1128 if (maybe_fail_all_tickets(fs_info, space_info)) {
1129 flush_state = FLUSH_DELAYED_ITEMS_NR;
1132 space_info->flush = 0;
1135 flush_state = FLUSH_DELAYED_ITEMS_NR;
1138 spin_unlock(&space_info->lock);
1139 } while (flush_state <= COMMIT_TRANS);
1143 * This handles pre-flushing of metadata space before we get to the point that
1144 * we need to start blocking threads on tickets. The logic here is different
1145 * from the other flush paths because it doesn't rely on tickets to tell us how
1146 * much we need to flush, instead it attempts to keep us below the 80% full
1147 * watermark of space by flushing whichever reservation pool is currently the
1150 static void btrfs_preempt_reclaim_metadata_space(struct work_struct *work)
1152 struct btrfs_fs_info *fs_info;
1153 struct btrfs_space_info *space_info;
1154 struct btrfs_block_rsv *delayed_block_rsv;
1155 struct btrfs_block_rsv *delayed_refs_rsv;
1156 struct btrfs_block_rsv *global_rsv;
1157 struct btrfs_block_rsv *trans_rsv;
1160 fs_info = container_of(work, struct btrfs_fs_info,
1161 preempt_reclaim_work);
1162 space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
1163 delayed_block_rsv = &fs_info->delayed_block_rsv;
1164 delayed_refs_rsv = &fs_info->delayed_refs_rsv;
1165 global_rsv = &fs_info->global_block_rsv;
1166 trans_rsv = &fs_info->trans_block_rsv;
1168 spin_lock(&space_info->lock);
1169 while (need_preemptive_reclaim(fs_info, space_info)) {
1170 enum btrfs_flush_state flush;
1171 u64 delalloc_size = 0;
1172 u64 to_reclaim, block_rsv_size;
1173 u64 global_rsv_size = global_rsv->reserved;
1178 * We don't have a precise counter for the metadata being
1179 * reserved for delalloc, so we'll approximate it by subtracting
1180 * out the block rsv's space from the bytes_may_use. If that
1181 * amount is higher than the individual reserves, then we can
1182 * assume it's tied up in delalloc reservations.
1184 block_rsv_size = global_rsv_size +
1185 delayed_block_rsv->reserved +
1186 delayed_refs_rsv->reserved +
1187 trans_rsv->reserved;
1188 if (block_rsv_size < space_info->bytes_may_use)
1189 delalloc_size = space_info->bytes_may_use - block_rsv_size;
1192 * We don't want to include the global_rsv in our calculation,
1193 * because that's space we can't touch. Subtract it from the
1194 * block_rsv_size for the next checks.
1196 block_rsv_size -= global_rsv_size;
1199 * We really want to avoid flushing delalloc too much, as it
1200 * could result in poor allocation patterns, so only flush it if
1201 * it's larger than the rest of the pools combined.
1203 if (delalloc_size > block_rsv_size) {
1204 to_reclaim = delalloc_size;
1205 flush = FLUSH_DELALLOC;
1206 } else if (space_info->bytes_pinned >
1207 (delayed_block_rsv->reserved +
1208 delayed_refs_rsv->reserved)) {
1209 to_reclaim = space_info->bytes_pinned;
1210 flush = COMMIT_TRANS;
1211 } else if (delayed_block_rsv->reserved >
1212 delayed_refs_rsv->reserved) {
1213 to_reclaim = delayed_block_rsv->reserved;
1214 flush = FLUSH_DELAYED_ITEMS_NR;
1216 to_reclaim = delayed_refs_rsv->reserved;
1217 flush = FLUSH_DELAYED_REFS_NR;
1220 spin_unlock(&space_info->lock);
1223 * We don't want to reclaim everything, just a portion, so scale
1224 * down the to_reclaim by 1/4. If it takes us down to 0,
1225 * reclaim 1 items worth.
1229 to_reclaim = btrfs_calc_insert_metadata_size(fs_info, 1);
1230 flush_space(fs_info, space_info, to_reclaim, flush, true);
1232 spin_lock(&space_info->lock);
1235 /* We only went through once, back off our clamping. */
1236 if (loops == 1 && !space_info->reclaim_size)
1237 space_info->clamp = max(1, space_info->clamp - 1);
1238 trace_btrfs_done_preemptive_reclaim(fs_info, space_info);
1239 spin_unlock(&space_info->lock);
1243 * FLUSH_DELALLOC_WAIT:
1244 * Space is freed from flushing delalloc in one of two ways.
1246 * 1) compression is on and we allocate less space than we reserved
1247 * 2) we are overwriting existing space
1249 * For #1 that extra space is reclaimed as soon as the delalloc pages are
1250 * COWed, by way of btrfs_add_reserved_bytes() which adds the actual extent
1251 * length to ->bytes_reserved, and subtracts the reserved space from
1254 * For #2 this is trickier. Once the ordered extent runs we will drop the
1255 * extent in the range we are overwriting, which creates a delayed ref for
1256 * that freed extent. This however is not reclaimed until the transaction
1257 * commits, thus the next stages.
1260 * If we are freeing inodes, we want to make sure all delayed iputs have
1261 * completed, because they could have been on an inode with i_nlink == 0, and
1262 * thus have been truncated and freed up space. But again this space is not
1263 * immediately re-usable, it comes in the form of a delayed ref, which must be
1264 * run and then the transaction must be committed.
1267 * This is where we reclaim all of the pinned space generated by running the
1271 * For data we start with alloc chunk force, however we could have been full
1272 * before, and then the transaction commit could have freed new block groups,
1273 * so if we now have space to allocate do the force chunk allocation.
1275 static const enum btrfs_flush_state data_flush_states[] = {
1276 FLUSH_DELALLOC_FULL,
1282 static void btrfs_async_reclaim_data_space(struct work_struct *work)
1284 struct btrfs_fs_info *fs_info;
1285 struct btrfs_space_info *space_info;
1286 u64 last_tickets_id;
1287 enum btrfs_flush_state flush_state = 0;
1289 fs_info = container_of(work, struct btrfs_fs_info, async_data_reclaim_work);
1290 space_info = fs_info->data_sinfo;
1292 spin_lock(&space_info->lock);
1293 if (list_empty(&space_info->tickets)) {
1294 space_info->flush = 0;
1295 spin_unlock(&space_info->lock);
1298 last_tickets_id = space_info->tickets_id;
1299 spin_unlock(&space_info->lock);
1301 while (!space_info->full) {
1302 flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE, false);
1303 spin_lock(&space_info->lock);
1304 if (list_empty(&space_info->tickets)) {
1305 space_info->flush = 0;
1306 spin_unlock(&space_info->lock);
1310 /* Something happened, fail everything and bail. */
1311 if (BTRFS_FS_ERROR(fs_info))
1313 last_tickets_id = space_info->tickets_id;
1314 spin_unlock(&space_info->lock);
1317 while (flush_state < ARRAY_SIZE(data_flush_states)) {
1318 flush_space(fs_info, space_info, U64_MAX,
1319 data_flush_states[flush_state], false);
1320 spin_lock(&space_info->lock);
1321 if (list_empty(&space_info->tickets)) {
1322 space_info->flush = 0;
1323 spin_unlock(&space_info->lock);
1327 if (last_tickets_id == space_info->tickets_id) {
1330 last_tickets_id = space_info->tickets_id;
1334 if (flush_state >= ARRAY_SIZE(data_flush_states)) {
1335 if (space_info->full) {
1336 if (maybe_fail_all_tickets(fs_info, space_info))
1339 space_info->flush = 0;
1344 /* Something happened, fail everything and bail. */
1345 if (BTRFS_FS_ERROR(fs_info))
1349 spin_unlock(&space_info->lock);
1354 maybe_fail_all_tickets(fs_info, space_info);
1355 space_info->flush = 0;
1356 spin_unlock(&space_info->lock);
1359 void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info)
1361 INIT_WORK(&fs_info->async_reclaim_work, btrfs_async_reclaim_metadata_space);
1362 INIT_WORK(&fs_info->async_data_reclaim_work, btrfs_async_reclaim_data_space);
1363 INIT_WORK(&fs_info->preempt_reclaim_work,
1364 btrfs_preempt_reclaim_metadata_space);
1367 static const enum btrfs_flush_state priority_flush_states[] = {
1368 FLUSH_DELAYED_ITEMS_NR,
1369 FLUSH_DELAYED_ITEMS,
1373 static const enum btrfs_flush_state evict_flush_states[] = {
1374 FLUSH_DELAYED_ITEMS_NR,
1375 FLUSH_DELAYED_ITEMS,
1376 FLUSH_DELAYED_REFS_NR,
1379 FLUSH_DELALLOC_WAIT,
1380 FLUSH_DELALLOC_FULL,
1385 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
1386 struct btrfs_space_info *space_info,
1387 struct reserve_ticket *ticket,
1388 const enum btrfs_flush_state *states,
1392 int flush_state = 0;
1394 spin_lock(&space_info->lock);
1395 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info);
1397 * This is the priority reclaim path, so to_reclaim could be >0 still
1398 * because we may have only satisfied the priority tickets and still
1399 * left non priority tickets on the list. We would then have
1400 * to_reclaim but ->bytes == 0.
1402 if (ticket->bytes == 0) {
1403 spin_unlock(&space_info->lock);
1407 while (flush_state < states_nr) {
1408 spin_unlock(&space_info->lock);
1409 flush_space(fs_info, space_info, to_reclaim, states[flush_state],
1412 spin_lock(&space_info->lock);
1413 if (ticket->bytes == 0) {
1414 spin_unlock(&space_info->lock);
1419 /* Attempt to steal from the global rsv if we can. */
1420 if (!steal_from_global_rsv(fs_info, space_info, ticket)) {
1421 ticket->error = -ENOSPC;
1422 remove_ticket(space_info, ticket);
1426 * We must run try_granting_tickets here because we could be a large
1427 * ticket in front of a smaller ticket that can now be satisfied with
1428 * the available space.
1430 btrfs_try_granting_tickets(fs_info, space_info);
1431 spin_unlock(&space_info->lock);
1434 static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info,
1435 struct btrfs_space_info *space_info,
1436 struct reserve_ticket *ticket)
1438 spin_lock(&space_info->lock);
1440 /* We could have been granted before we got here. */
1441 if (ticket->bytes == 0) {
1442 spin_unlock(&space_info->lock);
1446 while (!space_info->full) {
1447 spin_unlock(&space_info->lock);
1448 flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE, false);
1449 spin_lock(&space_info->lock);
1450 if (ticket->bytes == 0) {
1451 spin_unlock(&space_info->lock);
1456 ticket->error = -ENOSPC;
1457 remove_ticket(space_info, ticket);
1458 btrfs_try_granting_tickets(fs_info, space_info);
1459 spin_unlock(&space_info->lock);
1462 static void wait_reserve_ticket(struct btrfs_fs_info *fs_info,
1463 struct btrfs_space_info *space_info,
1464 struct reserve_ticket *ticket)
1470 spin_lock(&space_info->lock);
1471 while (ticket->bytes > 0 && ticket->error == 0) {
1472 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
1475 * Delete us from the list. After we unlock the space
1476 * info, we don't want the async reclaim job to reserve
1477 * space for this ticket. If that would happen, then the
1478 * ticket's task would not known that space was reserved
1479 * despite getting an error, resulting in a space leak
1480 * (bytes_may_use counter of our space_info).
1482 remove_ticket(space_info, ticket);
1483 ticket->error = -EINTR;
1486 spin_unlock(&space_info->lock);
1490 finish_wait(&ticket->wait, &wait);
1491 spin_lock(&space_info->lock);
1493 spin_unlock(&space_info->lock);
1497 * Do the appropriate flushing and waiting for a ticket.
1499 * @fs_info: the filesystem
1500 * @space_info: space info for the reservation
1501 * @ticket: ticket for the reservation
1502 * @start_ns: timestamp when the reservation started
1503 * @orig_bytes: amount of bytes originally reserved
1504 * @flush: how much we can flush
1506 * This does the work of figuring out how to flush for the ticket, waiting for
1507 * the reservation, and returning the appropriate error if there is one.
1509 static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
1510 struct btrfs_space_info *space_info,
1511 struct reserve_ticket *ticket,
1512 u64 start_ns, u64 orig_bytes,
1513 enum btrfs_reserve_flush_enum flush)
1518 case BTRFS_RESERVE_FLUSH_DATA:
1519 case BTRFS_RESERVE_FLUSH_ALL:
1520 case BTRFS_RESERVE_FLUSH_ALL_STEAL:
1521 wait_reserve_ticket(fs_info, space_info, ticket);
1523 case BTRFS_RESERVE_FLUSH_LIMIT:
1524 priority_reclaim_metadata_space(fs_info, space_info, ticket,
1525 priority_flush_states,
1526 ARRAY_SIZE(priority_flush_states));
1528 case BTRFS_RESERVE_FLUSH_EVICT:
1529 priority_reclaim_metadata_space(fs_info, space_info, ticket,
1531 ARRAY_SIZE(evict_flush_states));
1533 case BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE:
1534 priority_reclaim_data_space(fs_info, space_info, ticket);
1541 ret = ticket->error;
1542 ASSERT(list_empty(&ticket->list));
1544 * Check that we can't have an error set if the reservation succeeded,
1545 * as that would confuse tasks and lead them to error out without
1546 * releasing reserved space (if an error happens the expectation is that
1547 * space wasn't reserved at all).
1549 ASSERT(!(ticket->bytes == 0 && ticket->error));
1550 trace_btrfs_reserve_ticket(fs_info, space_info->flags, orig_bytes,
1551 start_ns, flush, ticket->error);
1556 * This returns true if this flush state will go through the ordinary flushing
1559 static inline bool is_normal_flushing(enum btrfs_reserve_flush_enum flush)
1561 return (flush == BTRFS_RESERVE_FLUSH_ALL) ||
1562 (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL);
1565 static inline void maybe_clamp_preempt(struct btrfs_fs_info *fs_info,
1566 struct btrfs_space_info *space_info)
1568 u64 ordered = percpu_counter_sum_positive(&fs_info->ordered_bytes);
1569 u64 delalloc = percpu_counter_sum_positive(&fs_info->delalloc_bytes);
1572 * If we're heavy on ordered operations then clamping won't help us. We
1573 * need to clamp specifically to keep up with dirty'ing buffered
1574 * writers, because there's not a 1:1 correlation of writing delalloc
1575 * and freeing space, like there is with flushing delayed refs or
1576 * delayed nodes. If we're already more ordered than delalloc then
1577 * we're keeping up, otherwise we aren't and should probably clamp.
1579 if (ordered < delalloc)
1580 space_info->clamp = min(space_info->clamp + 1, 8);
1583 static inline bool can_steal(enum btrfs_reserve_flush_enum flush)
1585 return (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL ||
1586 flush == BTRFS_RESERVE_FLUSH_EVICT);
1590 * NO_FLUSH and FLUSH_EMERGENCY don't want to create a ticket, they just want to
1591 * fail as quickly as possible.
1593 static inline bool can_ticket(enum btrfs_reserve_flush_enum flush)
1595 return (flush != BTRFS_RESERVE_NO_FLUSH &&
1596 flush != BTRFS_RESERVE_FLUSH_EMERGENCY);
1600 * Try to reserve bytes from the block_rsv's space.
1602 * @fs_info: the filesystem
1603 * @space_info: space info we want to allocate from
1604 * @orig_bytes: number of bytes we want
1605 * @flush: whether or not we can flush to make our reservation
1607 * This will reserve orig_bytes number of bytes from the space info associated
1608 * with the block_rsv. If there is not enough space it will make an attempt to
1609 * flush out space to make room. It will do this by flushing delalloc if
1610 * possible or committing the transaction. If flush is 0 then no attempts to
1611 * regain reservations will be made and this will fail if there is not enough
1614 static int __reserve_bytes(struct btrfs_fs_info *fs_info,
1615 struct btrfs_space_info *space_info, u64 orig_bytes,
1616 enum btrfs_reserve_flush_enum flush)
1618 struct work_struct *async_work;
1619 struct reserve_ticket ticket;
1623 bool pending_tickets;
1626 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
1628 if (flush == BTRFS_RESERVE_FLUSH_DATA)
1629 async_work = &fs_info->async_data_reclaim_work;
1631 async_work = &fs_info->async_reclaim_work;
1633 spin_lock(&space_info->lock);
1635 used = btrfs_space_info_used(space_info, true);
1638 * We don't want NO_FLUSH allocations to jump everybody, they can
1639 * generally handle ENOSPC in a different way, so treat them the same as
1640 * normal flushers when it comes to skipping pending tickets.
1642 if (is_normal_flushing(flush) || (flush == BTRFS_RESERVE_NO_FLUSH))
1643 pending_tickets = !list_empty(&space_info->tickets) ||
1644 !list_empty(&space_info->priority_tickets);
1646 pending_tickets = !list_empty(&space_info->priority_tickets);
1649 * Carry on if we have enough space (short-circuit) OR call
1650 * can_overcommit() to ensure we can overcommit to continue.
1652 if (!pending_tickets &&
1653 ((used + orig_bytes <= writable_total_bytes(fs_info, space_info)) ||
1654 btrfs_can_overcommit(fs_info, space_info, orig_bytes, flush))) {
1655 btrfs_space_info_update_bytes_may_use(fs_info, space_info,
1661 * Things are dire, we need to make a reservation so we don't abort. We
1662 * will let this reservation go through as long as we have actual space
1663 * left to allocate for the block.
1665 if (ret && unlikely(flush == BTRFS_RESERVE_FLUSH_EMERGENCY)) {
1666 used = btrfs_space_info_used(space_info, false);
1667 if (used + orig_bytes <=
1668 writable_total_bytes(fs_info, space_info)) {
1669 btrfs_space_info_update_bytes_may_use(fs_info, space_info,
1676 * If we couldn't make a reservation then setup our reservation ticket
1677 * and kick the async worker if it's not already running.
1679 * If we are a priority flusher then we just need to add our ticket to
1680 * the list and we will do our own flushing further down.
1682 if (ret && can_ticket(flush)) {
1683 ticket.bytes = orig_bytes;
1685 space_info->reclaim_size += ticket.bytes;
1686 init_waitqueue_head(&ticket.wait);
1687 ticket.steal = can_steal(flush);
1688 if (trace_btrfs_reserve_ticket_enabled())
1689 start_ns = ktime_get_ns();
1691 if (flush == BTRFS_RESERVE_FLUSH_ALL ||
1692 flush == BTRFS_RESERVE_FLUSH_ALL_STEAL ||
1693 flush == BTRFS_RESERVE_FLUSH_DATA) {
1694 list_add_tail(&ticket.list, &space_info->tickets);
1695 if (!space_info->flush) {
1697 * We were forced to add a reserve ticket, so
1698 * our preemptive flushing is unable to keep
1699 * up. Clamp down on the threshold for the
1700 * preemptive flushing in order to keep up with
1703 maybe_clamp_preempt(fs_info, space_info);
1705 space_info->flush = 1;
1706 trace_btrfs_trigger_flush(fs_info,
1710 queue_work(system_unbound_wq, async_work);
1713 list_add_tail(&ticket.list,
1714 &space_info->priority_tickets);
1716 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
1718 * We will do the space reservation dance during log replay,
1719 * which means we won't have fs_info->fs_root set, so don't do
1720 * the async reclaim as we will panic.
1722 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
1723 !work_busy(&fs_info->preempt_reclaim_work) &&
1724 need_preemptive_reclaim(fs_info, space_info)) {
1725 trace_btrfs_trigger_flush(fs_info, space_info->flags,
1726 orig_bytes, flush, "preempt");
1727 queue_work(system_unbound_wq,
1728 &fs_info->preempt_reclaim_work);
1731 spin_unlock(&space_info->lock);
1732 if (!ret || !can_ticket(flush))
1735 return handle_reserve_ticket(fs_info, space_info, &ticket, start_ns,
1740 * Try to reserve metadata bytes from the block_rsv's space.
1742 * @fs_info: the filesystem
1743 * @block_rsv: block_rsv we're allocating for
1744 * @orig_bytes: number of bytes we want
1745 * @flush: whether or not we can flush to make our reservation
1747 * This will reserve orig_bytes number of bytes from the space info associated
1748 * with the block_rsv. If there is not enough space it will make an attempt to
1749 * flush out space to make room. It will do this by flushing delalloc if
1750 * possible or committing the transaction. If flush is 0 then no attempts to
1751 * regain reservations will be made and this will fail if there is not enough
1754 int btrfs_reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
1755 struct btrfs_block_rsv *block_rsv,
1757 enum btrfs_reserve_flush_enum flush)
1761 ret = __reserve_bytes(fs_info, block_rsv->space_info, orig_bytes, flush);
1762 if (ret == -ENOSPC) {
1763 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
1764 block_rsv->space_info->flags,
1767 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1768 btrfs_dump_space_info(fs_info, block_rsv->space_info,
1775 * Try to reserve data bytes for an allocation.
1777 * @fs_info: the filesystem
1778 * @bytes: number of bytes we need
1779 * @flush: how we are allowed to flush
1781 * This will reserve bytes from the data space info. If there is not enough
1782 * space then we will attempt to flush space as specified by flush.
1784 int btrfs_reserve_data_bytes(struct btrfs_fs_info *fs_info, u64 bytes,
1785 enum btrfs_reserve_flush_enum flush)
1787 struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
1790 ASSERT(flush == BTRFS_RESERVE_FLUSH_DATA ||
1791 flush == BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE ||
1792 flush == BTRFS_RESERVE_NO_FLUSH);
1793 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_DATA);
1795 ret = __reserve_bytes(fs_info, data_sinfo, bytes, flush);
1796 if (ret == -ENOSPC) {
1797 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
1798 data_sinfo->flags, bytes, 1);
1799 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
1800 btrfs_dump_space_info(fs_info, data_sinfo, bytes, 0);
1805 /* Dump all the space infos when we abort a transaction due to ENOSPC. */
1806 __cold void btrfs_dump_space_info_for_trans_abort(struct btrfs_fs_info *fs_info)
1808 struct btrfs_space_info *space_info;
1810 btrfs_info(fs_info, "dumping space info:");
1811 list_for_each_entry(space_info, &fs_info->space_info, list) {
1812 spin_lock(&space_info->lock);
1813 __btrfs_dump_space_info(fs_info, space_info);
1814 spin_unlock(&space_info->lock);
1816 dump_global_block_rsv(fs_info);
1820 * Account the unused space of all the readonly block group in the space_info.
1821 * takes mirrors into account.
1823 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
1825 struct btrfs_block_group *block_group;
1829 /* It's df, we don't care if it's racy */
1830 if (list_empty(&sinfo->ro_bgs))
1833 spin_lock(&sinfo->lock);
1834 list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
1835 spin_lock(&block_group->lock);
1837 if (!block_group->ro) {
1838 spin_unlock(&block_group->lock);
1842 factor = btrfs_bg_type_to_factor(block_group->flags);
1843 free_bytes += (block_group->length -
1844 block_group->used) * factor;
1846 spin_unlock(&block_group->lock);
1848 spin_unlock(&sinfo->lock);