Re: [PATCH] ntfs: use base mft_no when looking up base inode for extent record

[Namjae Jeon]

On Thu, Apr 30, 2026 at 8:54 PM DaeMyung Kang <charsyam@xxxxxxxxx> wrote:
>
> When the mft record is an extent record, ntfs_may_write_mft_record()
> looks up its base inode in the icache. The hash key passed to
> find_inode_nowait() must be the base inode's mft number (na.mft_no,
> set just above to MREF_LE(m->base_mft_record)), but the code passes
> @mft_no, the extent record's own number.
>
> find_inode_nowait() uses its second argument as the hashval, so the
> lookup lands in the wrong bucket and almost always returns NULL.
> ntfs_may_write_mft_record() then returns false and the writeback
> path (ntfs_write_mft_block()) skips that extent record, leaving the
> on-disk copy permanently out of sync with the in-memory one.
>
> The original ilookup5_nowait() call this conversion replaced used
> na.mft_no.  Restore that.
>
> Fixes: 115380f9a2f9 ("ntfs: update mft operations")
> Signed-off-by: DaeMyung Kang <charsyam@xxxxxxxxx>
Applied it to #ntfs-next
Thanks!