xfs: add struct xfs_mount pointer to struct xfs_buf

We need to derive the mount pointer from a buffer in a lot of place.
Add a direct pointer to short cut the pointer chasing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/xfs/libxfs/xfs_dir2_node.c b/fs/xfs/libxfs/xfs_dir2_node.c
index 0a8fa45..747d14d 100644
--- a/fs/xfs/libxfs/xfs_dir2_node.c
+++ b/fs/xfs/libxfs/xfs_dir2_node.c
@@ -85,7 +85,7 @@ static xfs_failaddr_t
 xfs_dir3_free_verify(
 	struct xfs_buf		*bp)
 {
-	struct xfs_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_mount	*mp = bp->b_mount;
 	struct xfs_dir2_free_hdr *hdr = bp->b_addr;
 
 	if (!xfs_verify_magic(bp, hdr->magic))
@@ -111,7 +111,7 @@ static void
 xfs_dir3_free_read_verify(
 	struct xfs_buf	*bp)
 {
-	struct xfs_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_mount	*mp = bp->b_mount;
 	xfs_failaddr_t		fa;
 
 	if (xfs_sb_version_hascrc(&mp->m_sb) &&
@@ -128,7 +128,7 @@ static void
 xfs_dir3_free_write_verify(
 	struct xfs_buf	*bp)
 {
-	struct xfs_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_mount	*mp = bp->b_mount;
 	struct xfs_buf_log_item	*bip = bp->b_log_item;
 	struct xfs_dir3_blk_hdr	*hdr3 = bp->b_addr;
 	xfs_failaddr_t		fa;