xfs: add CRC checks to the AGI

Same set of changes made to the AGF need to be made to the AGI.
This patch has a similar history to the AGF, hence a similar
sign-off chain.

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

5 files changed, 65 insertions, 15 deletions

diff --git a/fs/xfs/xfs_ag.h b/fs/xfs/xfs_ag.h
index 272ef097e2be..317aa86d96ea 100644
--- a/fs/xfs/xfs_ag.h
+++ b/fs/xfs/xfs_ag.h
@@ -152,6 +152,7 @@ typedef struct xfs_agi {
         __be32          agi_root;       /* root of inode btree */
         __be32          agi_level;      /* levels in inode btree */
         __be32          agi_freecount;  /* number of free inodes */
+
         __be32          agi_newino;     /* new inode just allocated */
         __be32          agi_dirino;     /* last directory inode chunk */
         /*
@@ -159,6 +160,13 @@ typedef struct xfs_agi {
          * still being referenced.
          */
         __be32          agi_unlinked[XFS_AGI_UNLINKED_BUCKETS];
+
+        uuid_t          agi_uuid;       /* uuid of filesystem */
+        __be32          agi_crc;        /* crc of agi sector */
+        __be32          agi_pad32;
+        __be64          agi_lsn;        /* last write sequence */
+
+        /* structure must be padded to 64 bit alignment */
 } xfs_agi_t;
 
 #define XFS_AGI_MAGICNUM        0x00000001
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 067d5f0fc233..c25660691e08 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -47,6 +47,7 @@ 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_AGI_BUF         (1<<8)
 
 #define XFS_BLF_TYPE_MASK       \
                 (XFS_BLF_UDQUOT_BUF | \
@@ -54,7 +55,8 @@ extern kmem_zone_t	*xfs_buf_item_zone;
                  XFS_BLF_GDQUOT_BUF | \
                  XFS_BLF_BTREE_BUF | \
                  XFS_BLF_AGF_BUF | \
-                 XFS_BLF_AGFL_BUF)
+                 XFS_BLF_AGFL_BUF | \
+                 XFS_BLF_AGI_BUF)
 
 #define XFS_BLF_CHUNK           128
 #define XFS_BLF_SHIFT           7
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index a693a54799e5..87595b211da1 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -304,8 +304,11 @@ xfs_growfs_data_private(
                 agi->agi_freecount = 0;
                 agi->agi_newino = cpu_to_be32(NULLAGINO);
                 agi->agi_dirino = cpu_to_be32(NULLAGINO);
+                if (xfs_sb_version_hascrc(&mp->m_sb))
+                        uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_uuid);
                 for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
                         agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
+
                 error = xfs_bwrite(bp);
                 xfs_buf_relse(bp);
                 if (error)
diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index ba626613bf49..6d0a4954aa8c 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -36,6 +36,8 @@
 #include "xfs_rtalloc.h"
 #include "xfs_error.h"
 #include "xfs_bmap.h"
+#include "xfs_cksum.h"
+#include "xfs_buf_item.h"
 
 
 /*
@@ -1453,6 +1455,7 @@ xfs_ialloc_log_agi(
         /*
          * Log the allocation group inode header buffer.
          */
+        xfs_trans_buf_set_type(tp, bp, XFS_BLF_AGI_BUF);
         xfs_trans_log_buf(tp, bp, first, last);
 }
 
@@ -1470,19 +1473,23 @@ xfs_check_agi_unlinked(
 #define xfs_check_agi_unlinked(agi)
 #endif
 
-static void
+static bool
 xfs_agi_verify(
         struct xfs_buf  *bp)
 {
         struct xfs_mount *mp = bp->b_target->bt_mount;
         struct xfs_agi  *agi = XFS_BUF_TO_AGI(bp);
-        int             agi_ok;
 
+        if (xfs_sb_version_hascrc(&mp->m_sb) &&
+            !uuid_equal(&agi->agi_uuid, &mp->m_sb.sb_uuid))
+                        return false;
         /*
          * Validate the magic number of the agi block.
          */
-        agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&
-                XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum));
+        if (agi->agi_magicnum != cpu_to_be32(XFS_AGI_MAGIC))
+                return false;
+        if (!XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum)))
+                return false;
 
         /*
          * during growfs operations, the perag is not fully initialised,
@@ -1490,30 +1497,52 @@ xfs_agi_verify(
          * use it by using uncached buffers that don't have the perag attached
          * so we can detect and avoid this problem.
          */
-        if (bp->b_pag)
-                agi_ok = agi_ok && be32_to_cpu(agi->agi_seqno) ==
-                                                bp->b_pag->pag_agno;
+        if (bp->b_pag && be32_to_cpu(agi->agi_seqno) != bp->b_pag->pag_agno)
+                return false;
 
-        if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
-                        XFS_RANDOM_IALLOC_READ_AGI))) {
-                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, agi);
-                xfs_buf_ioerror(bp, EFSCORRUPTED);
-        }
         xfs_check_agi_unlinked(agi);
+        return true;
 }
 
 static void
 xfs_agi_read_verify(
         struct xfs_buf  *bp)
 {
-        xfs_agi_verify(bp);
+        struct xfs_mount *mp = bp->b_target->bt_mount;
+        int             agi_ok = 1;
+
+        if (xfs_sb_version_hascrc(&mp->m_sb))
+                agi_ok = xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
+                                          offsetof(struct xfs_agi, agi_crc));
+        agi_ok = agi_ok && xfs_agi_verify(bp);
+
+        if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
+                        XFS_RANDOM_IALLOC_READ_AGI))) {
+                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+                xfs_buf_ioerror(bp, EFSCORRUPTED);
+        }
 }
 
 static void
 xfs_agi_write_verify(
         struct xfs_buf  *bp)
 {
-        xfs_agi_verify(bp);
+        struct xfs_mount *mp = bp->b_target->bt_mount;
+        struct xfs_buf_log_item *bip = bp->b_fspriv;
+
+        if (!xfs_agi_verify(bp)) {
+                XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+                xfs_buf_ioerror(bp, EFSCORRUPTED);
+                return;
+        }
+
+        if (!xfs_sb_version_hascrc(&mp->m_sb))
+                return;
+
+        if (bip)
+                XFS_BUF_TO_AGI(bp)->agi_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+        xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
+                         offsetof(struct xfs_agi, agi_crc));
 }
 
 const struct xfs_buf_ops xfs_agi_buf_ops = {
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index da2a19e0554e..6778a7943db4 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -1971,6 +1971,14 @@ xlog_recover_do_reg_buffer(
                 }
                 bp->b_ops = &xfs_agfl_buf_ops;
                 break;
+        case XFS_BLF_AGI_BUF:
+                if (*(__be32 *)bp->b_addr != cpu_to_be32(XFS_AGI_MAGIC)) {
+                        xfs_warn(mp, "Bad AGI block magic!");
+                        ASSERT(0);
+                        break;
+                }
+                bp->b_ops = &xfs_agi_buf_ops;
+                break;
         default:
                 break;
         }