On Mon, Dec 02, 2019 at 09:36:25AM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> If sb_rootino doesn't point to where we think mkfs was supposed to have
> preallocated an inode chunk, check to see if the alleged root directory
> actually looks like a root directory. If so, we'll let it go because
> someone could have changed sunit since formatting time.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> repair/xfs_repair.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 49 insertions(+), 1 deletion(-)
>
>
> diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
> index 6798b88c..f6134cca 100644
> --- a/repair/xfs_repair.c
> +++ b/repair/xfs_repair.c
> @@ -395,12 +395,60 @@ do_log(char const *msg, ...)
> va_end(args);
> }
>
> +/*
> + * If sb_rootino points to a different inode than we were expecting, try
> + * loading the alleged root inode to see if it's a plausibly a root directory.
> + * If so, we'll readjust the computations.
"... readjust the calculated inode chunk range such that the root inode
is the first inode in the chunk."
> + */
> +static void
> +check_misaligned_root(
> + struct xfs_mount *mp)
> +{
> + struct xfs_inode *ip;
> + xfs_ino_t ino;
> + int error;
> +
> + error = -libxfs_iget(mp, NULL, mp->m_sb.sb_rootino, 0, &ip,
> + &xfs_default_ifork_ops);
> + if (error)
> + return;
> + if (!S_ISDIR(VFS_I(ip)->i_mode))
> + goto out_rele;
> +
> + error = -libxfs_dir_lookup(NULL, ip, &xfs_name_dotdot, &ino, NULL);
> + if (error)
> + goto out_rele;
> +
> + if (ino == mp->m_sb.sb_rootino) {
> + do_warn(
> +_("sb root inode value %" PRIu64 " inconsistent with calculated value %u but looks like a root directory\n"),
Just a nit, but I think the error would be more informative if it just
said something like:
"sb root inode %" PRIu64 " inconsistent with alignment (expected rootino %u)."
> + mp->m_sb.sb_rootino, first_prealloc_ino);
> + last_prealloc_ino += (int)ino - first_prealloc_ino;
> + first_prealloc_ino = ino;
Why assume ino > first_prealloc_ino? How about we just assign
last_prealloc_ino as done in _find_prealloc()?
Brian
> + }
> +
> +out_rele:
> + libxfs_irele(ip);
> +}
> +
> static void
> -calc_mkfs(xfs_mount_t *mp)
> +calc_mkfs(
> + struct xfs_mount *mp)
> {
> libxfs_ialloc_find_prealloc(mp, &first_prealloc_ino,
> &last_prealloc_ino);
>
> + /*
> + * If the root inode isn't where we think it is, check its plausibility
> + * as a root directory. It's possible that somebody changed sunit since
> + * the filesystem was created, which can change the value of the above
> + * computation. Try to avoid blowing up the filesystem if this is the
> + * case.
> + */
> + if (mp->m_sb.sb_rootino != NULLFSINO &&
> + mp->m_sb.sb_rootino != first_prealloc_ino)
> + check_misaligned_root(mp);
> +
> /*
> * now the first 3 inodes in the system
> */
>
