btrfs: zoned: fix initial free space detection

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When creating a new block group, it calls btrfs_add_new_free_space() to add
the entire block group range into the free space accounting.
__btrfs_add_free_space_zoned() checks if size == block_group->length to
detect the initial free space adding, and proceed that case properly.

However, if the zone_capacity == zone_size and the over-write speed is fast
enough, the entire zone can be over-written within one transaction. That
confuses __btrfs_add_free_space_zoned() to handle it as an initial free
space accounting. As a result, that block group becomes a strange state: 0
used bytes, 0 zone_unusable bytes, but alloc_offset == zone_capacity (no
allocation anymore).

The initial free space accounting can properly be checked by checking
alloc_offset too.

Fixes: 98173255bd ("btrfs: zoned: calculate free space from zone capacity")
CC: stable@vger.kernel.org # 6.1+
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>

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Naohiro Aota 2024-06-11 17:17:30 +09:00 • committed by David Sterba

parent d1825752e3

commit b9fd2affe4

1 changed files with 1 additions and 1 deletions

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fs/btrfs/free-space-cache.c

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