xfs: convert buffer verifiers to an ops structure.

To separate the verifiers from iodone functions and associate read
and write verifiers at the same time, introduce a buffer verifier
operations structure to the xfs_buf.

This avoids the need for assigning the write verifier, clearing the
iodone function and re-running ioend processing in the read
verifier, and gets rid of the nasty "b_pre_io" name for the write
verifier function pointer. If we ever need to, it will also be
easier to add further content specific callbacks to a buffer with an
ops structure in place.

We also avoid needing to export verifier functions, instead we
can simply export the ops structures for those that are needed
outside the function they are defined in.

This patch also fixes a directory block readahead verifier issue
it exposed.

This patch also adds ops callbacks to the inode/alloc btree blocks
initialised by growfs. These will need more work before they will
work with CRCs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index e2fdc6f..7536faa 100644
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -74,22 +74,24 @@ xfs_dir2_block_verify(
 }
 
 static void
-xfs_dir2_block_write_verify(
+xfs_dir2_block_read_verify(
 	struct xfs_buf	*bp)
 {
 	xfs_dir2_block_verify(bp);
 }
 
-void
-xfs_dir2_block_read_verify(
+static void
+xfs_dir2_block_write_verify(
 	struct xfs_buf	*bp)
 {
 	xfs_dir2_block_verify(bp);
-	bp->b_pre_io = xfs_dir2_block_write_verify;
-	bp->b_iodone = NULL;
-	xfs_buf_ioend(bp, 0);
 }
 
+const struct xfs_buf_ops xfs_dir2_block_buf_ops = {
+	.verify_read = xfs_dir2_block_read_verify,
+	.verify_write = xfs_dir2_block_write_verify,
+};
+
 static int
 xfs_dir2_block_read(
 	struct xfs_trans	*tp,
@@ -99,7 +101,7 @@ xfs_dir2_block_read(
 	struct xfs_mount	*mp = dp->i_mount;
 
 	return xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, bpp,
-				XFS_DATA_FORK, xfs_dir2_block_read_verify);
+				XFS_DATA_FORK, &xfs_dir2_block_buf_ops);
 }
 
 static void
@@ -1010,7 +1012,7 @@ xfs_dir2_leaf_to_block(
 	/*
 	 * Start converting it to block form.
 	 */
-	dbp->b_pre_io = xfs_dir2_block_write_verify;
+	dbp->b_ops = &xfs_dir2_block_buf_ops;
 	hdr->magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
 	needlog = 1;
 	needscan = 0;
@@ -1140,7 +1142,7 @@ xfs_dir2_sf_to_block(
 		kmem_free(sfp);
 		return error;
 	}
-	bp->b_pre_io = xfs_dir2_block_write_verify;
+	bp->b_ops = &xfs_dir2_block_buf_ops;
 	hdr = bp->b_addr;
 	hdr->magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);
 	/*