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, 4 insertions, 9 deletions

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c2f3fd93be5c..7e863d40380d 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -214,6 +214,8 @@ static int ocfs2_validate_dir_block(struct super_block *sb,
 	 * Nothing yet.  We don't validate dirents here, that's handled
 	 * in-place when the code walks them.
 	 */
+	mlog(0, "Validating dirblock %llu\n",
+	     (unsigned long long)bh->b_blocknr);
 
 	return 0;
 }
@@ -255,20 +257,13 @@ static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
 		goto out;
 	}
 
-	rc = ocfs2_read_blocks(inode, p_blkno, 1, &tmp, flags);
+	rc = ocfs2_read_blocks(inode, p_blkno, 1, &tmp, flags,
+			       ocfs2_validate_dir_block);
 	if (rc) {
 		mlog_errno(rc);
 		goto out;
 	}
 
-	if (!(flags & OCFS2_BH_READAHEAD)) {
-		rc = ocfs2_validate_dir_block(inode->i_sb, tmp);
-		if (rc) {
-			brelse(tmp);
-			goto out;
-		}
-	}
-
 	/* If ocfs2_read_blocks() got us a new bh, pass it up.  */
 	if (!*bh)
 		*bh = tmp;