Re: [PATCH] xfs_repair: Bump link count if longform_dir2_rebuild yields shortform dir

Bill O'Donnell
2025-04-15T18:23:09Z

On Tue, Apr 15, 2025 at 01:09:23PM -0500, user.mail wrote:
> From: Eric Sandeen <sandeen@redhat.com>
>
> If longform_dir2_rebuild() has so few entries in *hashtab that it results
> in a short form directory, bump the link count manually as shortform
> directories have no explicit "." entry.
>
> Without this, repair will end with i.e.:
>
> resetting inode 131 nlinks from 2 to 1
>
> in this case, because it thinks this directory inode only has 1 link
> discovered, and then a 2nd repair will fix it:
>
> resetting inode 131 nlinks from 1 to 2
>
> because shortform_dir2_entry_check() explicitly adds the extra ref when
> the (newly-created)shortform directory is checked:
>
> /*
> * no '.' entry in shortform dirs, just bump up ref count by 1
> * '..' was already (or will be) accounted for and checked when
> * the directory is reached or will be taken care of when the
> * directory is moved to orphanage.
> */
> add_inode_ref(current_irec, current_ino_offset);
>
> Avoid this by adding the extra ref if we convert from longform to
> shortform.
>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> Signed-off-by: user.mail <sandeen@redhat.com>
> ---

I was about to send a v3 of my patch to handle this (fix link counts
update...) based on djwong's review. This looks cleaner. Thanks!

Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>

> repair/phase6.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/repair/phase6.c b/repair/phase6.c
> index dbc090a5..8804278a 100644
> --- a/repair/phase6.c
> +++ b/repair/phase6.c
> @@ -1392,6 +1392,13 @@ _("name create failed in ino %" PRIu64 " (%d)\n"), ino, error);
> _("name create failed (%d) during rebuild\n"), error);
> }
>
> + /*
> + * If we added too few entries to retain longform, add the extra
> + * ref for . as this is now a shortform directory.
> + */
> + if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL)
> + add_inode_ref(irec, ino_offset);
> +
> return;
>
> out_bmap_cancel:
> --
> 2.49.0
>