Re: [PATCH 06/11] xfs_repair: check v5 filesystem attr block header sanity

Dave Chinner
2015-08-26T00:45:18Z

On Tue, Aug 25, 2015 at 05:32:59PM -0700, Darrick J. Wong wrote:
> Check the v5 fields (uuid, blocknr, owner) of attribute blocks for
> obvious errors while scanning xattr blocks. If the ownership info
> is incorrect, kill the block.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Why hasn't the buffer verifier done this validation?

> @@ -1564,6 +1602,13 @@ process_longform_attr(
> if (bp->b_error == -EFSBADCRC)
> (*repair)++;
>
> + /* is this block sane? */
> + if (__check_attr_header(mp, bp, ino)) {
> + *repair = 0;
> + libxfs_putbuf(bp);
> + return 1;
> + }

As you can see the above hunk has a bad CRC check from the verifier,
and if the attr header is wrong then the verifier should be setting
bp->b_error == -EFSCORRUPTED.

So shouldn't this simply be:

+ if (bp->b_error == -EFSCORRUPTED) {
+ *repair = 0;
+ libxfs_putbuf(bp);
+ return 1;
+ }
+

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com