Re: [PATCH v2] ext4: free the new extent block on failure to grow the tree

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [High] ext4: single-word name in Author and Signed-off-by trailer
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commit 28c8d79985e366b191e9eac1f2d5415854ca0289
Author: Alan <3164729207@qq.com>

> ext4: free the new extent block on failure to grow the tree
>
> ext4_ext_grow_indepth() allocates and accounts a metadata block before
> getting its buffer, obtaining journal create access and dirtying the
> new extent block. If any of these operations fails, the new block has
> not been linked into the extent tree. However, the error paths return
> without freeing it, leaking the block and leaving i_blocks larger
> than the number of blocks reachable from the inode.
>
> Commit 8a83ac54940d ("ext4: call bdev_getblk() from sb_getblk_gfp()")
> removed the implicit __GFP_NOFAIL from the buffer allocation, making
> the allocation failure path reachable. The two journal error paths
> already lacked cleanup before that commit and are fixed here as well.
>
> Route all three failures through a common cleanup label to free the
> unpublished metadata block and undo its inode accounting. Keep the
> existing buffer unlock and release handling. Once the new block has
> been linked by ext4_idx_store_pblock(), an ext4_mark_inode_dirty()
> failure must not free it because the extent tree already references it.
>
> Tested on Linux 6.12.1 by injecting NULL for buffer acquisition and
> -EIO for each of the two metadata helper calls at their caller
> boundaries. Each unfixed case leaves seven unreachable blocks and
> i_blocks of 40 instead of 32 on a filesystem with 4 KiB blocks. With
> the fix, all three cases retain i_blocks of 32, preserve the original
> data and pass e2fsck -fn after a normal unmount. Retry, truncate and
> uninjected growth also pass for each case.
>
> Fixes: 8a83ac54940d ("ext4: call bdev_getblk() from sb_getblk_gfp()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Alan <3164729207@qq.com>

[Severity: High]
Documentation/process/submitting-patches.rst requires a full real name in
the Author header and Signed-off-by trailer to satisfy the Developer's
Certificate of Origin, rather than a single-word name or handle ("Alan").

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Sashiko AI review · https://sashiko.dev/#/patchset/tencent_DF25FDEF46DA68C4E18D6DB40F08E30BB705@qq.com?part=1