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| author | Johannes Thumshirn <johannes.thumshirn@wdc.com> | 2026-05-22 11:02:47 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2026-05-26 16:35:03 +0200 |
| commit | cc8e2453c5f0ce218566ed095de5b7fec8870752 (patch) | |
| tree | 2d9cb171cebb30f82744280b9f4c6db33c19bdc8 /fs | |
| parent | 5f7724eaa159cfce6f3b62d2fe7509aec50a69de (diff) | |
| download | linux-next-history-cc8e2453c5f0ce218566ed095de5b7fec8870752.tar.gz | |
btrfs: zoned: fix deadlock waiting for ticket during data relocation
When performing data relocation on a zoned filesystem, BTRFS can deadlock
in handle_reserve_tickets(). The relocation process is waiting on a space
reservation ticket that can never be fulfilled, because the relocation
itself is the operation responsible for freeing up that space.
Fix this by introducing a new flush state,
BTRFS_RESERVE_FLUSH_ZONED_RELOCATION, specifically for data chunk
allocation during zoned relocation. Like
BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE, this state uses
priority_reclaim_data_space() instead of the normal flushing path, which
avoids re-entering the relocation code and breaking the deadlock cycle.
In btrfs_alloc_data_chunk_ondemand(), select this new flush state when the
inode belongs to a data relocation root on a zoned filesystem.
Fixes: e2a7fd22378f ("btrfs: zoned: add zone reclaim flush state for DATA space_info")
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/delalloc-space.c | 2 | ||||
| -rw-r--r-- | fs/btrfs/space-info.c | 2 | ||||
| -rw-r--r-- | fs/btrfs/space-info.h | 11 |
3 files changed, 15 insertions, 0 deletions
diff --git a/fs/btrfs/delalloc-space.c b/fs/btrfs/delalloc-space.c index 0970799d0aa44..4293a63834337 100644 --- a/fs/btrfs/delalloc-space.c +++ b/fs/btrfs/delalloc-space.c @@ -134,6 +134,8 @@ int btrfs_alloc_data_chunk_ondemand(const struct btrfs_inode *inode, u64 bytes) if (btrfs_is_free_space_inode(inode)) flush = BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE; + else if (btrfs_is_zoned(fs_info) && btrfs_is_data_reloc_root(root)) + flush = BTRFS_RESERVE_FLUSH_ZONED_RELOCATION; return btrfs_reserve_data_bytes(data_sinfo_for_inode(inode), bytes, flush); } diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 739984462677e..e6641597b321e 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -1705,6 +1705,7 @@ static int handle_reserve_ticket(struct btrfs_space_info *space_info, ARRAY_SIZE(evict_flush_states)); break; case BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE: + case BTRFS_RESERVE_FLUSH_ZONED_RELOCATION: priority_reclaim_data_space(space_info, ticket); break; default: @@ -1968,6 +1969,7 @@ int btrfs_reserve_data_bytes(struct btrfs_space_info *space_info, u64 bytes, ASSERT(flush == BTRFS_RESERVE_FLUSH_DATA || flush == BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE || + flush == BTRFS_RESERVE_FLUSH_ZONED_RELOCATION || flush == BTRFS_RESERVE_NO_FLUSH, "flush=%d", flush); ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_DATA, "current->journal_info=0x%lx flush=%d", diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h index 24f45072ca4b1..aa836e8a9d4a6 100644 --- a/fs/btrfs/space-info.h +++ b/fs/btrfs/space-info.h @@ -78,6 +78,17 @@ enum btrfs_reserve_flush_enum { BTRFS_RESERVE_FLUSH_ALL_STEAL, /* + * This is for relocation on zoned filesystems only. We need to use + * priority flushing for this, because otherwise we can deadlock on + * waiting for a ticket, that cannot be granted, because we cannot do + * any allocations. + * + * Apart from being specific to zoned relocation, it is equal to + * BTRFS_FLUSH_FREE_SPACE_INODE. + */ + BTRFS_RESERVE_FLUSH_ZONED_RELOCATION, + + /* * This is for btrfs_use_block_rsv only. We have exhausted our block * rsv and our global block rsv. This can happen for things like * delalloc where we are overwriting a lot of extents with a single |