xfs: add CRC checks for quota blocks

Use the reserved space in struct xfs_dqblk to store a UUID and a crc
for the quota blocks.

[dchinner@redhat.com] Add a LSN field and update for current verifier
infrastructure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 20 insertions, 3 deletions

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index d0acb4e..f41702b 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -617,6 +617,20 @@ xfs_qm_dqdetach(
 	}
 }
 
+int
+xfs_qm_calc_dquots_per_chunk(
+	struct xfs_mount	*mp,
+	unsigned int		nbblks)	/* basic block units */
+{
+	unsigned int	ndquots;
+
+	ASSERT(nbblks > 0);
+	ndquots = BBTOB(nbblks);
+	do_div(ndquots, sizeof(xfs_dqblk_t));
+
+	return ndquots;
+}
+
 /*
  * This initializes all the quota information that's kept in the
  * mount structure
@@ -656,9 +670,8 @@ xfs_qm_init_quotainfo(
 
 	/* Precalc some constants */
 	qinf->qi_dqchunklen = XFS_FSB_TO_BB(mp, XFS_DQUOT_CLUSTER_SIZE_FSB);
-	ASSERT(qinf->qi_dqchunklen);
-	qinf->qi_dqperchunk = BBTOB(qinf->qi_dqchunklen);
-	do_div(qinf->qi_dqperchunk, sizeof(xfs_dqblk_t));
+	qinf->qi_dqperchunk = xfs_qm_calc_dquots_per_chunk(mp,
+							qinf->qi_dqchunklen);
 
 	mp->m_qflags |= (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_CHKD);
 
@@ -897,6 +910,10 @@ xfs_qm_dqiter_bufs(
 		if (error)
 			break;
 
+		/*
+		 * XXX(hch): need to figure out if it makes sense to validate
+		 *	     the CRC here.
+		 */
 		xfs_qm_reset_dqcounts(mp, bp, firstid, type);
 		xfs_buf_delwri_queue(bp, buffer_list);
 		xfs_buf_relse(bp);