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 d0acb4e40a6f..f41702b43003 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);