[PATCH 13/13] xfs_repair: validate & fix inode CRCs

[Brian Foster]

On Tue, Mar 17, 2015 at 03:33:15PM -0500, Eric Sandeen wrote:
> xfs_repair doesn't ever check an inode's CRC, so it never repairs
> them.  If the root inode or realtime inodes have bad crcs, the
> fs won't even mount and can't be fixed (without using xfs_db).
> 
> It's fairly straightforward to just test the inode CRC before
> we do any other checking or modification of the inode, and
> just mark it dirty if it's wrong and needs to be re-written.
> 
> Signed-off-by: Eric Sandeen <sandeen at redhat.com>
> ---
>  repair/dinode.c |   24 ++++++++++++++++++++++++
>  1 files changed, 24 insertions(+), 0 deletions(-)
> 
> diff --git a/repair/dinode.c b/repair/dinode.c
> index 5d9094b..05db838 100644
> --- a/repair/dinode.c
> +++ b/repair/dinode.c
> @@ -2291,6 +2291,30 @@ process_dinode_int(xfs_mount_t *mp,
>  	 */
>  	ASSERT(uncertain == 0 || verify_mode != 0);
>  
> +	/*
> +	 * This is the only valid point to check the CRC; after this we may have
> +	 * made changes which invalidate it, and the CRC is only updated again
> +	 * when it gets written out.
> +	 *
> +	 * Of course if we make any modifications after this, the inode gets
> +	 * rewritten, and the CRC is updated automagically.
> +	 */
> +	if (xfs_sb_version_hascrc(&mp->m_sb) &&
> +	    !xfs_verify_cksum((char *)dino, mp->m_sb.sb_inodesize,
> +                		XFS_DINODE_CRC_OFF)) {

   ^^^^^^ whitespace ;)

Otherwise looks good to me:

Reviewed-by: Brian Foster <bfoster at redhat.com>

> +		retval = 1;
> +		if (!uncertain)
> +			do_warn(_("bad CRC for inode %" PRIu64 "%c"),
> +				lino, verify_mode ? '\n' : ',');
> +		if (!verify_mode) {
> +			if (!no_modify) {
> +				do_warn(_(" will rewrite\n"));
> +				*dirty = 1;
> +			} else
> +				do_warn(_(" would rewrite\n"));
> +		}
> +	}
> +
>  	if (be16_to_cpu(dino->di_magic) != XFS_DINODE_MAGIC)  {
>  		retval = 1;
>  		if (!uncertain)
> -- 
> 1.7.1
> 
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