Re: [PATCH v5] ntfs: handle a failed size rollback in the write error path

[Hyunchul Lee]

On Wed, Oct 21, 2026 at 02:32:21PM +0800, Hongling Zeng wrote:
> ntfs_file_write_iter() extends the data and initialized sizes before
> it copies the user data and restores them when the write then fails.
> The restoration is best-effort: both results are discarded, even
> though the extension is already recorded in the dirty MFT record.
> When the restoration fails too, the extended sizes reach the disk
> while the VFS inode keeps reporting the old ones: after a remount the
> file appears grown again, with an uninitialized tail where the failed
> write never put any data, and nothing records the failure.
> 
> Keep both undo results: roll the initialized size back first, and
> roll the data size back only when that rollback succeeded.  The data
> rollback goes through the same VFS-facing truncate
> ntfs_setattr_size() uses, which also supports compressed attributes,
> and keeps the VFS size on the durable data size when it fails.  Its
> shrink clamps the initialized size to the rolled-back data size,
> which can sit above the old initialized size, so a failed initialized
> size rollback would leave the clamp in place and expose the
> uninitialized tail.  The undo runs under the mapping invalidate lock,
> like ntfs_setattr_size(), which the truncate expects.  On an undo
> failure, set NVolSetErrors(), which the next persistence point
> persists as VOLUME_IS_DIRTY, and log a message for the errors=
> policy.
> 
> Fixes: 9c87959601e8 ("ntfs: update file operations")
> Suggested-by: Hyunchul Lee <hyc.lee@xxxxxxxxx>
> Signed-off-by: Hongling Zeng <zenghongling@xxxxxxxxxx>

Looks good to me.

Reviewed-by: Hyunchul Lee <hyc.lee@xxxxxxxxx>

-- 
Thanks,
Hyunchul