Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
new file mode 100644
index 0000000..e8a4b0e
--- /dev/null
+++ b/fs/btrfs/space-info.c
@@ -0,0 +1,1117 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "misc.h"
+#include "ctree.h"
+#include "space-info.h"
+#include "sysfs.h"
+#include "volumes.h"
+#include "free-space-cache.h"
+#include "ordered-data.h"
+#include "transaction.h"
+#include "block-group.h"
+
+u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
+ bool may_use_included)
+{
+ ASSERT(s_info);
+ return s_info->bytes_used + s_info->bytes_reserved +
+ s_info->bytes_pinned + s_info->bytes_readonly +
+ (may_use_included ? s_info->bytes_may_use : 0);
+}
+
+/*
+ * after adding space to the filesystem, we need to clear the full flags
+ * on all the space infos.
+ */
+void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
+{
+ struct list_head *head = &info->space_info;
+ struct btrfs_space_info *found;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(found, head, list)
+ found->full = 0;
+ rcu_read_unlock();
+}
+
+static int create_space_info(struct btrfs_fs_info *info, u64 flags)
+{
+
+ struct btrfs_space_info *space_info;
+ int i;
+ int ret;
+
+ space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
+ if (!space_info)
+ return -ENOMEM;
+
+ ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
+ GFP_KERNEL);
+ if (ret) {
+ kfree(space_info);
+ return ret;
+ }
+
+ for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
+ INIT_LIST_HEAD(&space_info->block_groups[i]);
+ init_rwsem(&space_info->groups_sem);
+ spin_lock_init(&space_info->lock);
+ space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
+ space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
+ init_waitqueue_head(&space_info->wait);
+ INIT_LIST_HEAD(&space_info->ro_bgs);
+ INIT_LIST_HEAD(&space_info->tickets);
+ INIT_LIST_HEAD(&space_info->priority_tickets);
+
+ ret = btrfs_sysfs_add_space_info_type(info, space_info);
+ if (ret)
+ return ret;
+
+ list_add_rcu(&space_info->list, &info->space_info);
+ if (flags & BTRFS_BLOCK_GROUP_DATA)
+ info->data_sinfo = space_info;
+
+ return ret;
+}
+
+int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_super_block *disk_super;
+ u64 features;
+ u64 flags;
+ int mixed = 0;
+ int ret;
+
+ disk_super = fs_info->super_copy;
+ if (!btrfs_super_root(disk_super))
+ return -EINVAL;
+
+ features = btrfs_super_incompat_flags(disk_super);
+ if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
+ mixed = 1;
+
+ flags = BTRFS_BLOCK_GROUP_SYSTEM;
+ ret = create_space_info(fs_info, flags);
+ if (ret)
+ goto out;
+
+ if (mixed) {
+ flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
+ ret = create_space_info(fs_info, flags);
+ } else {
+ flags = BTRFS_BLOCK_GROUP_METADATA;
+ ret = create_space_info(fs_info, flags);
+ if (ret)
+ goto out;
+
+ flags = BTRFS_BLOCK_GROUP_DATA;
+ ret = create_space_info(fs_info, flags);
+ }
+out:
+ return ret;
+}
+
+void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags,
+ u64 total_bytes, u64 bytes_used,
+ u64 bytes_readonly,
+ struct btrfs_space_info **space_info)
+{
+ struct btrfs_space_info *found;
+ int factor;
+
+ factor = btrfs_bg_type_to_factor(flags);
+
+ found = btrfs_find_space_info(info, flags);
+ ASSERT(found);
+ spin_lock(&found->lock);
+ found->total_bytes += total_bytes;
+ found->disk_total += total_bytes * factor;
+ found->bytes_used += bytes_used;
+ found->disk_used += bytes_used * factor;
+ found->bytes_readonly += bytes_readonly;
+ if (total_bytes > 0)
+ found->full = 0;
+ btrfs_try_granting_tickets(info, found);
+ spin_unlock(&found->lock);
+ *space_info = found;
+}
+
+struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info,
+ u64 flags)
+{
+ struct list_head *head = &info->space_info;
+ struct btrfs_space_info *found;
+
+ flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(found, head, list) {
+ if (found->flags & flags) {
+ rcu_read_unlock();
+ return found;
+ }
+ }
+ rcu_read_unlock();
+ return NULL;
+}
+
+static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
+{
+ return (global->size << 1);
+}
+
+static int can_overcommit(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info, u64 bytes,
+ enum btrfs_reserve_flush_enum flush,
+ bool system_chunk)
+{
+ u64 profile;
+ u64 avail;
+ u64 used;
+ int factor;
+
+ /* Don't overcommit when in mixed mode. */
+ if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
+ return 0;
+
+ if (system_chunk)
+ profile = btrfs_system_alloc_profile(fs_info);
+ else
+ profile = btrfs_metadata_alloc_profile(fs_info);
+
+ used = btrfs_space_info_used(space_info, true);
+ avail = atomic64_read(&fs_info->free_chunk_space);
+
+ /*
+ * If we have dup, raid1 or raid10 then only half of the free
+ * space is actually usable. For raid56, the space info used
+ * doesn't include the parity drive, so we don't have to
+ * change the math
+ */
+ factor = btrfs_bg_type_to_factor(profile);
+ avail = div_u64(avail, factor);
+
+ /*
+ * If we aren't flushing all things, let us overcommit up to
+ * 1/2th of the space. If we can flush, don't let us overcommit
+ * too much, let it overcommit up to 1/8 of the space.
+ */
+ if (flush == BTRFS_RESERVE_FLUSH_ALL)
+ avail >>= 3;
+ else
+ avail >>= 1;
+
+ if (used + bytes < space_info->total_bytes + avail)
+ return 1;
+ return 0;
+}
+
+/*
+ * This is for space we already have accounted in space_info->bytes_may_use, so
+ * basically when we're returning space from block_rsv's.
+ */
+void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info)
+{
+ struct list_head *head;
+ enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
+
+ lockdep_assert_held(&space_info->lock);
+
+ head = &space_info->priority_tickets;
+again:
+ while (!list_empty(head)) {
+ struct reserve_ticket *ticket;
+ u64 used = btrfs_space_info_used(space_info, true);
+
+ ticket = list_first_entry(head, struct reserve_ticket, list);
+
+ /* Check and see if our ticket can be satisified now. */
+ if ((used + ticket->bytes <= space_info->total_bytes) ||
+ can_overcommit(fs_info, space_info, ticket->bytes, flush,
+ false)) {
+ btrfs_space_info_update_bytes_may_use(fs_info,
+ space_info,
+ ticket->bytes);
+ list_del_init(&ticket->list);
+ ticket->bytes = 0;
+ space_info->tickets_id++;
+ wake_up(&ticket->wait);
+ } else {
+ break;
+ }
+ }
+
+ if (head == &space_info->priority_tickets) {
+ head = &space_info->tickets;
+ flush = BTRFS_RESERVE_FLUSH_ALL;
+ goto again;
+ }
+}
+
+#define DUMP_BLOCK_RSV(fs_info, rsv_name) \
+do { \
+ struct btrfs_block_rsv *__rsv = &(fs_info)->rsv_name; \
+ spin_lock(&__rsv->lock); \
+ btrfs_info(fs_info, #rsv_name ": size %llu reserved %llu", \
+ __rsv->size, __rsv->reserved); \
+ spin_unlock(&__rsv->lock); \
+} while (0)
+
+static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *info)
+{
+ lockdep_assert_held(&info->lock);
+
+ btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
+ info->flags,
+ info->total_bytes - btrfs_space_info_used(info, true),
+ info->full ? "" : "not ");
+ btrfs_info(fs_info,
+ "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
+ info->total_bytes, info->bytes_used, info->bytes_pinned,
+ info->bytes_reserved, info->bytes_may_use,
+ info->bytes_readonly);
+
+ DUMP_BLOCK_RSV(fs_info, global_block_rsv);
+ DUMP_BLOCK_RSV(fs_info, trans_block_rsv);
+ DUMP_BLOCK_RSV(fs_info, chunk_block_rsv);
+ DUMP_BLOCK_RSV(fs_info, delayed_block_rsv);
+ DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv);
+
+}
+
+void btrfs_dump_space_info(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *info, u64 bytes,
+ int dump_block_groups)
+{
+ struct btrfs_block_group_cache *cache;
+ int index = 0;
+
+ spin_lock(&info->lock);
+ __btrfs_dump_space_info(fs_info, info);
+ spin_unlock(&info->lock);
+
+ if (!dump_block_groups)
+ return;
+
+ down_read(&info->groups_sem);
+again:
+ list_for_each_entry(cache, &info->block_groups[index], list) {
+ spin_lock(&cache->lock);
+ btrfs_info(fs_info,
+ "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
+ cache->key.objectid, cache->key.offset,
+ btrfs_block_group_used(&cache->item), cache->pinned,
+ cache->reserved, cache->ro ? "[readonly]" : "");
+ btrfs_dump_free_space(cache, bytes);
+ spin_unlock(&cache->lock);
+ }
+ if (++index < BTRFS_NR_RAID_TYPES)
+ goto again;
+ up_read(&info->groups_sem);
+}
+
+static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
+ unsigned long nr_pages, int nr_items)
+{
+ struct super_block *sb = fs_info->sb;
+
+ if (down_read_trylock(&sb->s_umount)) {
+ writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
+ up_read(&sb->s_umount);
+ } else {
+ /*
+ * We needn't worry the filesystem going from r/w to r/o though
+ * we don't acquire ->s_umount mutex, because the filesystem
+ * should guarantee the delalloc inodes list be empty after
+ * the filesystem is readonly(all dirty pages are written to
+ * the disk).
+ */
+ btrfs_start_delalloc_roots(fs_info, nr_items);
+ if (!current->journal_info)
+ btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
+ }
+}
+
+static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
+ u64 to_reclaim)
+{
+ u64 bytes;
+ u64 nr;
+
+ bytes = btrfs_calc_insert_metadata_size(fs_info, 1);
+ nr = div64_u64(to_reclaim, bytes);
+ if (!nr)
+ nr = 1;
+ return nr;
+}
+
+#define EXTENT_SIZE_PER_ITEM SZ_256K
+
+/*
+ * shrink metadata reservation for delalloc
+ */
+static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
+ u64 orig, bool wait_ordered)
+{
+ struct btrfs_space_info *space_info;
+ struct btrfs_trans_handle *trans;
+ u64 delalloc_bytes;
+ u64 dio_bytes;
+ u64 async_pages;
+ u64 items;
+ long time_left;
+ unsigned long nr_pages;
+ int loops;
+
+ /* Calc the number of the pages we need flush for space reservation */
+ items = calc_reclaim_items_nr(fs_info, to_reclaim);
+ to_reclaim = items * EXTENT_SIZE_PER_ITEM;
+
+ trans = (struct btrfs_trans_handle *)current->journal_info;
+ space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
+
+ delalloc_bytes = percpu_counter_sum_positive(
+ &fs_info->delalloc_bytes);
+ dio_bytes = percpu_counter_sum_positive(&fs_info->dio_bytes);
+ if (delalloc_bytes == 0 && dio_bytes == 0) {
+ if (trans)
+ return;
+ if (wait_ordered)
+ btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
+ return;
+ }
+
+ /*
+ * If we are doing more ordered than delalloc we need to just wait on
+ * ordered extents, otherwise we'll waste time trying to flush delalloc
+ * that likely won't give us the space back we need.
+ */
+ if (dio_bytes > delalloc_bytes)
+ wait_ordered = true;
+
+ loops = 0;
+ while ((delalloc_bytes || dio_bytes) && loops < 3) {
+ nr_pages = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT;
+
+ /*
+ * Triggers inode writeback for up to nr_pages. This will invoke
+ * ->writepages callback and trigger delalloc filling
+ * (btrfs_run_delalloc_range()).
+ */
+ btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
+
+ /*
+ * We need to wait for the compressed pages to start before
+ * we continue.
+ */
+ async_pages = atomic_read(&fs_info->async_delalloc_pages);
+ if (!async_pages)
+ goto skip_async;
+
+ /*
+ * Calculate how many compressed pages we want to be written
+ * before we continue. I.e if there are more async pages than we
+ * require wait_event will wait until nr_pages are written.
+ */
+ if (async_pages <= nr_pages)
+ async_pages = 0;
+ else
+ async_pages -= nr_pages;
+
+ wait_event(fs_info->async_submit_wait,
+ atomic_read(&fs_info->async_delalloc_pages) <=
+ (int)async_pages);
+skip_async:
+ spin_lock(&space_info->lock);
+ if (list_empty(&space_info->tickets) &&
+ list_empty(&space_info->priority_tickets)) {
+ spin_unlock(&space_info->lock);
+ break;
+ }
+ spin_unlock(&space_info->lock);
+
+ loops++;
+ if (wait_ordered && !trans) {
+ btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
+ } else {
+ time_left = schedule_timeout_killable(1);
+ if (time_left)
+ break;
+ }
+ delalloc_bytes = percpu_counter_sum_positive(
+ &fs_info->delalloc_bytes);
+ dio_bytes = percpu_counter_sum_positive(&fs_info->dio_bytes);
+ }
+}
+
+/**
+ * maybe_commit_transaction - possibly commit the transaction if its ok to
+ * @root - the root we're allocating for
+ * @bytes - the number of bytes we want to reserve
+ * @force - force the commit
+ *
+ * This will check to make sure that committing the transaction will actually
+ * get us somewhere and then commit the transaction if it does. Otherwise it
+ * will return -ENOSPC.
+ */
+static int may_commit_transaction(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info)
+{
+ struct reserve_ticket *ticket = NULL;
+ struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
+ struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
+ struct btrfs_trans_handle *trans;
+ u64 bytes_needed;
+ u64 reclaim_bytes = 0;
+ u64 cur_free_bytes = 0;
+
+ trans = (struct btrfs_trans_handle *)current->journal_info;
+ if (trans)
+ return -EAGAIN;
+
+ spin_lock(&space_info->lock);
+ cur_free_bytes = btrfs_space_info_used(space_info, true);
+ if (cur_free_bytes < space_info->total_bytes)
+ cur_free_bytes = space_info->total_bytes - cur_free_bytes;
+ else
+ cur_free_bytes = 0;
+
+ if (!list_empty(&space_info->priority_tickets))
+ ticket = list_first_entry(&space_info->priority_tickets,
+ struct reserve_ticket, list);
+ else if (!list_empty(&space_info->tickets))
+ ticket = list_first_entry(&space_info->tickets,
+ struct reserve_ticket, list);
+ bytes_needed = (ticket) ? ticket->bytes : 0;
+
+ if (bytes_needed > cur_free_bytes)
+ bytes_needed -= cur_free_bytes;
+ else
+ bytes_needed = 0;
+ spin_unlock(&space_info->lock);
+
+ if (!bytes_needed)
+ return 0;
+
+ trans = btrfs_join_transaction(fs_info->extent_root);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ /*
+ * See if there is enough pinned space to make this reservation, or if
+ * we have block groups that are going to be freed, allowing us to
+ * possibly do a chunk allocation the next loop through.
+ */
+ if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags) ||
+ __percpu_counter_compare(&space_info->total_bytes_pinned,
+ bytes_needed,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH) >= 0)
+ goto commit;
+
+ /*
+ * See if there is some space in the delayed insertion reservation for
+ * this reservation.
+ */
+ if (space_info != delayed_rsv->space_info)
+ goto enospc;
+
+ spin_lock(&delayed_rsv->lock);
+ reclaim_bytes += delayed_rsv->reserved;
+ spin_unlock(&delayed_rsv->lock);
+
+ spin_lock(&delayed_refs_rsv->lock);
+ reclaim_bytes += delayed_refs_rsv->reserved;
+ spin_unlock(&delayed_refs_rsv->lock);
+ if (reclaim_bytes >= bytes_needed)
+ goto commit;
+ bytes_needed -= reclaim_bytes;
+
+ if (__percpu_counter_compare(&space_info->total_bytes_pinned,
+ bytes_needed,
+ BTRFS_TOTAL_BYTES_PINNED_BATCH) < 0)
+ goto enospc;
+
+commit:
+ return btrfs_commit_transaction(trans);
+enospc:
+ btrfs_end_transaction(trans);
+ return -ENOSPC;
+}
+
+/*
+ * Try to flush some data based on policy set by @state. This is only advisory
+ * and may fail for various reasons. The caller is supposed to examine the
+ * state of @space_info to detect the outcome.
+ */
+static void flush_space(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info, u64 num_bytes,
+ int state)
+{
+ struct btrfs_root *root = fs_info->extent_root;
+ struct btrfs_trans_handle *trans;
+ int nr;
+ int ret = 0;
+
+ switch (state) {
+ case FLUSH_DELAYED_ITEMS_NR:
+ case FLUSH_DELAYED_ITEMS:
+ if (state == FLUSH_DELAYED_ITEMS_NR)
+ nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
+ else
+ nr = -1;
+
+ trans = btrfs_join_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ break;
+ }
+ ret = btrfs_run_delayed_items_nr(trans, nr);
+ btrfs_end_transaction(trans);
+ break;
+ case FLUSH_DELALLOC:
+ case FLUSH_DELALLOC_WAIT:
+ shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
+ state == FLUSH_DELALLOC_WAIT);
+ break;
+ case FLUSH_DELAYED_REFS_NR:
+ case FLUSH_DELAYED_REFS:
+ trans = btrfs_join_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ break;
+ }
+ if (state == FLUSH_DELAYED_REFS_NR)
+ nr = calc_reclaim_items_nr(fs_info, num_bytes);
+ else
+ nr = 0;
+ btrfs_run_delayed_refs(trans, nr);
+ btrfs_end_transaction(trans);
+ break;
+ case ALLOC_CHUNK:
+ case ALLOC_CHUNK_FORCE:
+ trans = btrfs_join_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ break;
+ }
+ ret = btrfs_chunk_alloc(trans,
+ btrfs_metadata_alloc_profile(fs_info),
+ (state == ALLOC_CHUNK) ? CHUNK_ALLOC_NO_FORCE :
+ CHUNK_ALLOC_FORCE);
+ btrfs_end_transaction(trans);
+ if (ret > 0 || ret == -ENOSPC)
+ ret = 0;
+ break;
+ case RUN_DELAYED_IPUTS:
+ /*
+ * If we have pending delayed iputs then we could free up a
+ * bunch of pinned space, so make sure we run the iputs before
+ * we do our pinned bytes check below.
+ */
+ btrfs_run_delayed_iputs(fs_info);
+ btrfs_wait_on_delayed_iputs(fs_info);
+ break;
+ case COMMIT_TRANS:
+ ret = may_commit_transaction(fs_info, space_info);
+ break;
+ default:
+ ret = -ENOSPC;
+ break;
+ }
+
+ trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
+ ret);
+ return;
+}
+
+static inline u64
+btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info,
+ bool system_chunk)
+{
+ struct reserve_ticket *ticket;
+ u64 used;
+ u64 expected;
+ u64 to_reclaim = 0;
+
+ list_for_each_entry(ticket, &space_info->tickets, list)
+ to_reclaim += ticket->bytes;
+ list_for_each_entry(ticket, &space_info->priority_tickets, list)
+ to_reclaim += ticket->bytes;
+ if (to_reclaim)
+ return to_reclaim;
+
+ to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
+ if (can_overcommit(fs_info, space_info, to_reclaim,
+ BTRFS_RESERVE_FLUSH_ALL, system_chunk))
+ return 0;
+
+ used = btrfs_space_info_used(space_info, true);
+
+ if (can_overcommit(fs_info, space_info, SZ_1M,
+ BTRFS_RESERVE_FLUSH_ALL, system_chunk))
+ expected = div_factor_fine(space_info->total_bytes, 95);
+ else
+ expected = div_factor_fine(space_info->total_bytes, 90);
+
+ if (used > expected)
+ to_reclaim = used - expected;
+ else
+ to_reclaim = 0;
+ to_reclaim = min(to_reclaim, space_info->bytes_may_use +
+ space_info->bytes_reserved);
+ return to_reclaim;
+}
+
+static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info,
+ u64 used, bool system_chunk)
+{
+ u64 thresh = div_factor_fine(space_info->total_bytes, 98);
+
+ /* If we're just plain full then async reclaim just slows us down. */
+ if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
+ return 0;
+
+ if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
+ system_chunk))
+ return 0;
+
+ return (used >= thresh && !btrfs_fs_closing(fs_info) &&
+ !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
+}
+
+/*
+ * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets
+ * @fs_info - fs_info for this fs
+ * @space_info - the space info we were flushing
+ *
+ * We call this when we've exhausted our flushing ability and haven't made
+ * progress in satisfying tickets. The reservation code handles tickets in
+ * order, so if there is a large ticket first and then smaller ones we could
+ * very well satisfy the smaller tickets. This will attempt to wake up any
+ * tickets in the list to catch this case.
+ *
+ * This function returns true if it was able to make progress by clearing out
+ * other tickets, or if it stumbles across a ticket that was smaller than the
+ * first ticket.
+ */
+static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info)
+{
+ struct reserve_ticket *ticket;
+ u64 tickets_id = space_info->tickets_id;
+ u64 first_ticket_bytes = 0;
+
+ if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
+ btrfs_info(fs_info, "cannot satisfy tickets, dumping space info");
+ __btrfs_dump_space_info(fs_info, space_info);
+ }
+
+ while (!list_empty(&space_info->tickets) &&
+ tickets_id == space_info->tickets_id) {
+ ticket = list_first_entry(&space_info->tickets,
+ struct reserve_ticket, list);
+
+ /*
+ * may_commit_transaction will avoid committing the transaction
+ * if it doesn't feel like the space reclaimed by the commit
+ * would result in the ticket succeeding. However if we have a
+ * smaller ticket in the queue it may be small enough to be
+ * satisified by committing the transaction, so if any
+ * subsequent ticket is smaller than the first ticket go ahead
+ * and send us back for another loop through the enospc flushing
+ * code.
+ */
+ if (first_ticket_bytes == 0)
+ first_ticket_bytes = ticket->bytes;
+ else if (first_ticket_bytes > ticket->bytes)
+ return true;
+
+ if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
+ btrfs_info(fs_info, "failing ticket with %llu bytes",
+ ticket->bytes);
+
+ list_del_init(&ticket->list);
+ ticket->error = -ENOSPC;
+ wake_up(&ticket->wait);
+
+ /*
+ * We're just throwing tickets away, so more flushing may not
+ * trip over btrfs_try_granting_tickets, so we need to call it
+ * here to see if we can make progress with the next ticket in
+ * the list.
+ */
+ btrfs_try_granting_tickets(fs_info, space_info);
+ }
+ return (tickets_id != space_info->tickets_id);
+}
+
+/*
+ * This is for normal flushers, we can wait all goddamned day if we want to. We
+ * will loop and continuously try to flush as long as we are making progress.
+ * We count progress as clearing off tickets each time we have to loop.
+ */
+static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
+{
+ struct btrfs_fs_info *fs_info;
+ struct btrfs_space_info *space_info;
+ u64 to_reclaim;
+ int flush_state;
+ int commit_cycles = 0;
+ u64 last_tickets_id;
+
+ fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
+ space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
+
+ spin_lock(&space_info->lock);
+ to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
+ false);
+ if (!to_reclaim) {
+ space_info->flush = 0;
+ spin_unlock(&space_info->lock);
+ return;
+ }
+ last_tickets_id = space_info->tickets_id;
+ spin_unlock(&space_info->lock);
+
+ flush_state = FLUSH_DELAYED_ITEMS_NR;
+ do {
+ flush_space(fs_info, space_info, to_reclaim, flush_state);
+ spin_lock(&space_info->lock);
+ if (list_empty(&space_info->tickets)) {
+ space_info->flush = 0;
+ spin_unlock(&space_info->lock);
+ return;
+ }
+ to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
+ space_info,
+ false);
+ if (last_tickets_id == space_info->tickets_id) {
+ flush_state++;
+ } else {
+ last_tickets_id = space_info->tickets_id;
+ flush_state = FLUSH_DELAYED_ITEMS_NR;
+ if (commit_cycles)
+ commit_cycles--;
+ }
+
+ /*
+ * We don't want to force a chunk allocation until we've tried
+ * pretty hard to reclaim space. Think of the case where we
+ * freed up a bunch of space and so have a lot of pinned space
+ * to reclaim. We would rather use that than possibly create a
+ * underutilized metadata chunk. So if this is our first run
+ * through the flushing state machine skip ALLOC_CHUNK_FORCE and
+ * commit the transaction. If nothing has changed the next go
+ * around then we can force a chunk allocation.
+ */
+ if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles)
+ flush_state++;
+
+ if (flush_state > COMMIT_TRANS) {
+ commit_cycles++;
+ if (commit_cycles > 2) {
+ if (maybe_fail_all_tickets(fs_info, space_info)) {
+ flush_state = FLUSH_DELAYED_ITEMS_NR;
+ commit_cycles--;
+ } else {
+ space_info->flush = 0;
+ }
+ } else {
+ flush_state = FLUSH_DELAYED_ITEMS_NR;
+ }
+ }
+ spin_unlock(&space_info->lock);
+ } while (flush_state <= COMMIT_TRANS);
+}
+
+void btrfs_init_async_reclaim_work(struct work_struct *work)
+{
+ INIT_WORK(work, btrfs_async_reclaim_metadata_space);
+}
+
+static const enum btrfs_flush_state priority_flush_states[] = {
+ FLUSH_DELAYED_ITEMS_NR,
+ FLUSH_DELAYED_ITEMS,
+ ALLOC_CHUNK,
+};
+
+static const enum btrfs_flush_state evict_flush_states[] = {
+ FLUSH_DELAYED_ITEMS_NR,
+ FLUSH_DELAYED_ITEMS,
+ FLUSH_DELAYED_REFS_NR,
+ FLUSH_DELAYED_REFS,
+ FLUSH_DELALLOC,
+ FLUSH_DELALLOC_WAIT,
+ ALLOC_CHUNK,
+ COMMIT_TRANS,
+};
+
+static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info,
+ struct reserve_ticket *ticket,
+ const enum btrfs_flush_state *states,
+ int states_nr)
+{
+ u64 to_reclaim;
+ int flush_state;
+
+ spin_lock(&space_info->lock);
+ to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
+ false);
+ if (!to_reclaim) {
+ spin_unlock(&space_info->lock);
+ return;
+ }
+ spin_unlock(&space_info->lock);
+
+ flush_state = 0;
+ do {
+ flush_space(fs_info, space_info, to_reclaim, states[flush_state]);
+ flush_state++;
+ spin_lock(&space_info->lock);
+ if (ticket->bytes == 0) {
+ spin_unlock(&space_info->lock);
+ return;
+ }
+ spin_unlock(&space_info->lock);
+ } while (flush_state < states_nr);
+}
+
+static void wait_reserve_ticket(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info,
+ struct reserve_ticket *ticket)
+
+{
+ DEFINE_WAIT(wait);
+ int ret = 0;
+
+ spin_lock(&space_info->lock);
+ while (ticket->bytes > 0 && ticket->error == 0) {
+ ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
+ if (ret) {
+ /*
+ * Delete us from the list. After we unlock the space
+ * info, we don't want the async reclaim job to reserve
+ * space for this ticket. If that would happen, then the
+ * ticket's task would not known that space was reserved
+ * despite getting an error, resulting in a space leak
+ * (bytes_may_use counter of our space_info).
+ */
+ list_del_init(&ticket->list);
+ ticket->error = -EINTR;
+ break;
+ }
+ spin_unlock(&space_info->lock);
+
+ schedule();
+
+ finish_wait(&ticket->wait, &wait);
+ spin_lock(&space_info->lock);
+ }
+ spin_unlock(&space_info->lock);
+}
+
+/**
+ * handle_reserve_ticket - do the appropriate flushing and waiting for a ticket
+ * @fs_info - the fs
+ * @space_info - the space_info for the reservation
+ * @ticket - the ticket for the reservation
+ * @flush - how much we can flush
+ *
+ * This does the work of figuring out how to flush for the ticket, waiting for
+ * the reservation, and returning the appropriate error if there is one.
+ */
+static int handle_reserve_ticket(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info,
+ struct reserve_ticket *ticket,
+ enum btrfs_reserve_flush_enum flush)
+{
+ int ret;
+
+ switch (flush) {
+ case BTRFS_RESERVE_FLUSH_ALL:
+ wait_reserve_ticket(fs_info, space_info, ticket);
+ break;
+ case BTRFS_RESERVE_FLUSH_LIMIT:
+ priority_reclaim_metadata_space(fs_info, space_info, ticket,
+ priority_flush_states,
+ ARRAY_SIZE(priority_flush_states));
+ break;
+ case BTRFS_RESERVE_FLUSH_EVICT:
+ priority_reclaim_metadata_space(fs_info, space_info, ticket,
+ evict_flush_states,
+ ARRAY_SIZE(evict_flush_states));
+ break;
+ default:
+ ASSERT(0);
+ break;
+ }
+
+ spin_lock(&space_info->lock);
+ ret = ticket->error;
+ if (ticket->bytes || ticket->error) {
+ /*
+ * Need to delete here for priority tickets. For regular tickets
+ * either the async reclaim job deletes the ticket from the list
+ * or we delete it ourselves at wait_reserve_ticket().
+ */
+ list_del_init(&ticket->list);
+ if (!ret)
+ ret = -ENOSPC;
+ }
+ spin_unlock(&space_info->lock);
+ ASSERT(list_empty(&ticket->list));
+ /*
+ * Check that we can't have an error set if the reservation succeeded,
+ * as that would confuse tasks and lead them to error out without
+ * releasing reserved space (if an error happens the expectation is that
+ * space wasn't reserved at all).
+ */
+ ASSERT(!(ticket->bytes == 0 && ticket->error));
+ return ret;
+}
+
+/**
+ * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
+ * @root - the root we're allocating for
+ * @space_info - the space info we want to allocate from
+ * @orig_bytes - the number of bytes we want
+ * @flush - whether or not we can flush to make our reservation
+ *
+ * This will reserve orig_bytes number of bytes from the space info associated
+ * with the block_rsv. If there is not enough space it will make an attempt to
+ * flush out space to make room. It will do this by flushing delalloc if
+ * possible or committing the transaction. If flush is 0 then no attempts to
+ * regain reservations will be made and this will fail if there is not enough
+ * space already.
+ */
+static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
+ struct btrfs_space_info *space_info,
+ u64 orig_bytes,
+ enum btrfs_reserve_flush_enum flush,
+ bool system_chunk)
+{
+ struct reserve_ticket ticket;
+ u64 used;
+ int ret = 0;
+ bool pending_tickets;
+
+ ASSERT(orig_bytes);
+ ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
+
+ spin_lock(&space_info->lock);
+ ret = -ENOSPC;
+ used = btrfs_space_info_used(space_info, true);
+ pending_tickets = !list_empty(&space_info->tickets) ||
+ !list_empty(&space_info->priority_tickets);
+
+ /*
+ * Carry on if we have enough space (short-circuit) OR call
+ * can_overcommit() to ensure we can overcommit to continue.
+ */
+ if (!pending_tickets &&
+ ((used + orig_bytes <= space_info->total_bytes) ||
+ can_overcommit(fs_info, space_info, orig_bytes, flush,
+ system_chunk))) {
+ btrfs_space_info_update_bytes_may_use(fs_info, space_info,
+ orig_bytes);
+ ret = 0;
+ }
+
+ /*
+ * If we couldn't make a reservation then setup our reservation ticket
+ * and kick the async worker if it's not already running.
+ *
+ * If we are a priority flusher then we just need to add our ticket to
+ * the list and we will do our own flushing further down.
+ */
+ if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
+ ticket.bytes = orig_bytes;
+ ticket.error = 0;
+ init_waitqueue_head(&ticket.wait);
+ if (flush == BTRFS_RESERVE_FLUSH_ALL) {
+ list_add_tail(&ticket.list, &space_info->tickets);
+ if (!space_info->flush) {
+ space_info->flush = 1;
+ trace_btrfs_trigger_flush(fs_info,
+ space_info->flags,
+ orig_bytes, flush,
+ "enospc");
+ queue_work(system_unbound_wq,
+ &fs_info->async_reclaim_work);
+ }
+ } else {
+ list_add_tail(&ticket.list,
+ &space_info->priority_tickets);
+ }
+ } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
+ used += orig_bytes;
+ /*
+ * We will do the space reservation dance during log replay,
+ * which means we won't have fs_info->fs_root set, so don't do
+ * the async reclaim as we will panic.
+ */
+ if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
+ need_do_async_reclaim(fs_info, space_info,
+ used, system_chunk) &&
+ !work_busy(&fs_info->async_reclaim_work)) {
+ trace_btrfs_trigger_flush(fs_info, space_info->flags,
+ orig_bytes, flush, "preempt");
+ queue_work(system_unbound_wq,
+ &fs_info->async_reclaim_work);
+ }
+ }
+ spin_unlock(&space_info->lock);
+ if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
+ return ret;
+
+ return handle_reserve_ticket(fs_info, space_info, &ticket, flush);
+}
+
+/**
+ * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
+ * @root - the root we're allocating for
+ * @block_rsv - the block_rsv we're allocating for
+ * @orig_bytes - the number of bytes we want
+ * @flush - whether or not we can flush to make our reservation
+ *
+ * This will reserve orig_bytes number of bytes from the space info associated
+ * with the block_rsv. If there is not enough space it will make an attempt to
+ * flush out space to make room. It will do this by flushing delalloc if
+ * possible or committing the transaction. If flush is 0 then no attempts to
+ * regain reservations will be made and this will fail if there is not enough
+ * space already.
+ */
+int btrfs_reserve_metadata_bytes(struct btrfs_root *root,
+ struct btrfs_block_rsv *block_rsv,
+ u64 orig_bytes,
+ enum btrfs_reserve_flush_enum flush)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
+ int ret;
+ bool system_chunk = (root == fs_info->chunk_root);
+
+ ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
+ orig_bytes, flush, system_chunk);
+ if (ret == -ENOSPC &&
+ unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
+ if (block_rsv != global_rsv &&
+ !btrfs_block_rsv_use_bytes(global_rsv, orig_bytes))
+ ret = 0;
+ }
+ if (ret == -ENOSPC) {
+ trace_btrfs_space_reservation(fs_info, "space_info:enospc",
+ block_rsv->space_info->flags,
+ orig_bytes, 1);
+
+ if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
+ btrfs_dump_space_info(fs_info, block_rsv->space_info,
+ orig_bytes, 0);
+ }
+ return ret;
+}