Re: [PATCH v2 2/2] ext4: track zeroed out blocks of unwritten extents for fast commit

[sashiko-bot@kernel.org]

> From: Daejun Park <daejun7.park@samsung.com>
> 
> When ext4_ext_convert_to_initialized() converts part of an unwritten
> extent, it may zero out the blocks before and after that range (a side
> only if it fits together with the range in s_extent_max_zeroout_kb,
> 32 KiB by default, and the extent ends within i_disksize or the write)
> and convert them to written together with it, instead of splitting them
> off. ext4_split_extent() zeroes out the rest of the extent and converts
> all of it when a split fails with -ENOSPC, -EDQUOT or -ENOMEM. In both
> cases ext4_map_blocks() reports only the mapped range to fast commit, so
> the other converted blocks are not tracked.
> 
> A later write to one of those blocks overwrites a written block in
> place. That changes no mapping and is not tracked either, so the next
> fsync is a fast commit that logs the inode but no range for the block.
> [ ... ]
> 
> Fixes: aa75f4d3daae ("ext4: main fast-commit commit path")
> Cc: stable@vger.kernel.org
> Suggested-by: Jan Kara <jack@suse.cz>
> Signed-off-by: Daejun Park <daejun7.park@samsung.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261008-ext4-fc-zeroout-v2-0-55cab1e24fa3@samsung.com?part=2