ocfs2: Validate metadata only when it's read from disk.

Add an optional validation hook to ocfs2_read_blocks().  Now the
validation function is only called when a block was actually read off of
disk.  It is not called when the buffer was in cache.

We add a buffer state bit BH_NeedsValidate to flag these buffers.  It
must always be one higher than the last JBD2 buffer state bit.

The dinode, dirblock, extent_block, and xattr_block validators are
lifted to this scheme directly.  The group_descriptor validator needs to
be split into two pieces.  The first part only needs the gd buffer and
is passed to ocfs2_read_block().  The second part requires the dinode as
well, and is called every time.  It's only 3 compares, so it's tiny.
This also allows us to clean up the non-fatal gd check used by resize.c.
It now has no magic argument.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 5 insertions, 13 deletions

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 9eb701b86466..ec3497bafda6 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1255,6 +1255,9 @@ int ocfs2_validate_inode_block(struct super_block *sb,
         int rc = -EINVAL;
         struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;
 
+        mlog(0, "Validating dinode %llu\n",
+             (unsigned long long)bh->b_blocknr);
+
         BUG_ON(!buffer_uptodate(bh));
 
         if (!OCFS2_IS_VALID_DINODE(di)) {
@@ -1300,23 +1303,12 @@ int ocfs2_read_inode_block_full(struct inode *inode, struct buffer_head **bh,
         struct buffer_head *tmp = *bh;
 
         rc = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, &tmp,
-                               flags);
-        if (rc)
-                goto out;
-
-        if (!(flags & OCFS2_BH_READAHEAD)) {
-                rc = ocfs2_validate_inode_block(inode->i_sb, tmp);
-                if (rc) {
-                        brelse(tmp);
-                        goto out;
-                }
-        }
+                               flags, ocfs2_validate_inode_block);
 
         /* If ocfs2_read_blocks() got us a new bh, pass it up. */
-        if (!*bh)
+        if (!rc && !*bh)
                 *bh = tmp;
 
-out:
         return rc;
 }