The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e30729d4bd4001881be4d1ad4332a5d4985398f8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024081951-enrich-hesitate-0db0@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

e30729d4bd40 ("btrfs: zoned: properly take lock to read/update block group's zoned variables") 8cd44dd1d17a ("btrfs: zoned: fix zone_unusable accounting on making block group read-write again") b9fd2affe4aa ("btrfs: zoned: fix initial free space detection") 6a8ebc773ef6 ("btrfs: zoned: no longer count fresh BG region as zone unusable") fa2068d7e922 ("btrfs: zoned: count fresh BG region as zone unusable") 3349b57fd47b ("btrfs: convert block group bit field to use bit helpers") 9d4b0a129a0d ("btrfs: simplify arguments of btrfs_update_space_info and rename") 6ca64ac27631 ("btrfs: zoned: fix mounting with conventional zones") ced8ecf026fd ("btrfs: fix space cache corruption and potential double allocations") b09315139136 ("btrfs: zoned: activate metadata block group on flush_space") 6a921de58992 ("btrfs: zoned: introduce space_info->active_total_bytes") 393f646e34c1 ("btrfs: zoned: finish least available block group on data bg allocation") bb9950d3df71 ("btrfs: let can_allocate_chunk return error") f6fca3917b4d ("btrfs: store chunk size in space-info struct") b8bea09a456f ("btrfs: add trace event for submitted RAID56 bio") c67c68eb57f1 ("btrfs: use integrated bitmaps for btrfs_raid_bio::dbitmap and finish_pbitmap") 143823cf4d5a ("btrfs: fix typos in comments") b3a3b0255797 ("btrfs: zoned: drop optimization of zone finish") 343d8a30851c ("btrfs: zoned: prevent allocation from previous data relocation BG") d70cbdda75da ("btrfs: zoned: consolidate zone finish functions")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e30729d4bd4001881be4d1ad4332a5d4985398f8 Mon Sep 17 00:00:00 2001 From: Naohiro Aota naohiro.aota@wdc.com Date: Thu, 1 Aug 2024 16:47:52 +0900 Subject: [PATCH] btrfs: zoned: properly take lock to read/update block group's zoned variables

__btrfs_add_free_space_zoned() references and modifies bg's alloc_offset, ro, and zone_unusable, but without taking the lock. It is mostly safe because they monotonically increase (at least for now) and this function is mostly called by a transaction commit, which is serialized by itself.

Still, taking the lock is a safer and correct option and I'm going to add a change to reset zone_unusable while a block group is still alive. So, add locking around the operations.

Fixes: 169e0da91a21 ("btrfs: zoned: track unusable bytes for zones") CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index f5996a43db24..eaa1dbd31352 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -2697,15 +2697,16 @@ static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group, u64 offset = bytenr - block_group->start; u64 to_free, to_unusable; int bg_reclaim_threshold = 0; - bool initial = ((size == block_group->length) && (block_group->alloc_offset == 0)); + bool initial; u64 reclaimable_unusable;

- WARN_ON(!initial && offset + size > block_group->zone_capacity); + spin_lock(&block_group->lock);

+ initial = ((size == block_group->length) && (block_group->alloc_offset == 0)); + WARN_ON(!initial && offset + size > block_group->zone_capacity); if (!initial) bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);

- spin_lock(&ctl->tree_lock); if (!used) to_free = size; else if (initial) @@ -2718,7 +2719,9 @@ static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group, to_free = offset + size - block_group->alloc_offset; to_unusable = size - to_free;

+ spin_lock(&ctl->tree_lock); ctl->free_space += to_free; + spin_unlock(&ctl->tree_lock); /* * If the block group is read-only, we should account freed space into * bytes_readonly. @@ -2727,11 +2730,8 @@ static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group, block_group->zone_unusable += to_unusable; WARN_ON(block_group->zone_unusable > block_group->length); } - spin_unlock(&ctl->tree_lock); if (!used) { - spin_lock(&block_group->lock); block_group->alloc_offset -= size; - spin_unlock(&block_group->lock); }

reclaimable_unusable = block_group->zone_unusable - @@ -2745,6 +2745,8 @@ static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group, btrfs_mark_bg_to_reclaim(block_group); }

+ spin_unlock(&block_group->lock); + return 0; }