xfs: add CRC checks to the AGFL

Add CRC checks, location information and a magic number to the AGFL.
Previously the AGFL was just a block containing nothing but the
free block pointers.  The new AGFL has a real header with the usual
boilerplate instead, so that we can verify it's not corrupted and
written into the right place.

[dchinner@redhat.com] Added LSN field, reworked significantly to fit
into new verifier structure and growfs structure, enabled full
verifier functionality now there is a header to verify and we can
guarantee an initialised AGFL.

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, 3 insertions, 1 deletions

diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 76bd7a167a70..067d5f0fc233 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -46,13 +46,15 @@ extern kmem_zone_t	*xfs_buf_item_zone;
  */
 #define XFS_BLF_BTREE_BUF       (1<<5)
 #define XFS_BLF_AGF_BUF         (1<<6)
+#define XFS_BLF_AGFL_BUF        (1<<7)
 
 #define XFS_BLF_TYPE_MASK       \
                 (XFS_BLF_UDQUOT_BUF | \
                  XFS_BLF_PDQUOT_BUF | \
                  XFS_BLF_GDQUOT_BUF | \
                  XFS_BLF_BTREE_BUF | \
-                 XFS_BLF_AGF_BUF)
+                 XFS_BLF_AGF_BUF | \
+                 XFS_BLF_AGFL_BUF)
 
 #define XFS_BLF_CHUNK           128
 #define XFS_BLF_SHIFT           7