xfs: add pre-write metadata buffer verifier callbacks

These verifiers are essentially the same code as the read verifiers,
but do not require ioend processing. Hence factor the read verifier
functions and add a new write verifier wrapper that is used as the
callback.

This is done as one large patch for all verifiers rather than one
patch per verifier as the change is largely mechanical. This
includes hooking up the write verifier via the read verifier
function.

Hooking up the write verifier for buffers obtained via
xfs_trans_get_buf() will be done in a separate patch as that touches
code in many different places rather than just the verifier
functions.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 25 insertions, 12 deletions

diff --git a/fs/xfs/xfs_da_btree.c b/fs/xfs/xfs_da_btree.c
index 93ebc0fc6dd9..6bb0a59eaaee 100644
--- a/fs/xfs/xfs_da_btree.c
+++ b/fs/xfs/xfs_da_btree.c
@@ -92,7 +92,7 @@ STATIC int	xfs_da_blk_unlink(xfs_da_state_t *state,
 STATIC void	xfs_da_state_kill_altpath(xfs_da_state_t *state);
 
 static void
-__xfs_da_node_verify(
+xfs_da_node_verify(
 	struct xfs_buf		*bp)
 {
 	struct xfs_mount	*mp = bp->b_target->bt_mount;
@@ -108,12 +108,17 @@ __xfs_da_node_verify(
 		xfs_buf_ioerror(bp, EFSCORRUPTED);
 	}
 
-	bp->b_iodone = NULL;
-	xfs_buf_ioend(bp, 0);
 }
 
 static void
-xfs_da_node_verify(
+xfs_da_node_write_verify(
+	struct xfs_buf	*bp)
+{
+	xfs_da_node_verify(bp);
+}
+
+static void
+xfs_da_node_read_verify(
 	struct xfs_buf		*bp)
 {
 	struct xfs_mount	*mp = bp->b_target->bt_mount;
@@ -121,21 +126,22 @@ xfs_da_node_verify(
 
 	switch (be16_to_cpu(info->magic)) {
 		case XFS_DA_NODE_MAGIC:
-			__xfs_da_node_verify(bp);
-			return;
+			xfs_da_node_verify(bp);
+			break;
 		case XFS_ATTR_LEAF_MAGIC:
-			xfs_attr_leaf_verify(bp);
+			xfs_attr_leaf_read_verify(bp);
 			return;
 		case XFS_DIR2_LEAFN_MAGIC:
-			xfs_dir2_leafn_verify(bp);
+			xfs_dir2_leafn_read_verify(bp);
 			return;
 		default:
+			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW,
+					     mp, info);
+			xfs_buf_ioerror(bp, EFSCORRUPTED);
 			break;
 	}
 
-	XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, info);
-	xfs_buf_ioerror(bp, EFSCORRUPTED);
-
+	bp->b_pre_io = xfs_da_node_write_verify;
 	bp->b_iodone = NULL;
 	xfs_buf_ioend(bp, 0);
 }
@@ -150,7 +156,7 @@ xfs_da_node_read(
 	int			which_fork)
 {
 	return xfs_da_read_buf(tp, dp, bno, mappedbno, bpp,
-					which_fork, xfs_da_node_verify);
+					which_fork, xfs_da_node_read_verify);
 }
 
 /*========================================================================
@@ -816,7 +822,14 @@ xfs_da_root_join(xfs_da_state_t *state, xfs_da_state_blk_t *root_blk)
 	xfs_da_blkinfo_onlychild_validate(bp->b_addr,
 					be16_to_cpu(oldroot->hdr.level));
 
+	/*
+	 * This could be copying a leaf back into the root block in the case of
+	 * there only being a single leaf block left in the tree. Hence we have
+	 * to update the pre_io pointer as well to match the buffer type change
+	 * that could occur.
+	 */
 	memcpy(root_blk->bp->b_addr, bp->b_addr, state->blocksize);
+	root_blk->bp->b_pre_io = bp->b_pre_io;
 	xfs_trans_log_buf(args->trans, root_blk->bp, 0, state->blocksize - 1);
 	error = xfs_da_shrink_inode(args, child, bp);
 	return(error);