xfs: factor dir2 free block reading

Also factor out the updating of the free block when removing entries
from leaf blocks, and add a verifier callback for reads.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Phil White <pwhite@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_dir2_priv.h b/fs/xfs/xfs_dir2_priv.h
index 93b8f66..263a632 100644
--- a/fs/xfs/xfs_dir2_priv.h
+++ b/fs/xfs/xfs_dir2_priv.h
@@ -117,6 +117,8 @@
 extern int xfs_dir2_node_replace(struct xfs_da_args *args);
 extern int xfs_dir2_node_trim_free(struct xfs_da_args *args, xfs_fileoff_t fo,
 		int *rvalp);
+extern int xfs_dir2_free_read(struct xfs_trans *tp, struct xfs_inode *dp,
+		xfs_dablk_t fbno, struct xfs_buf **bpp);
 
 /* xfs_dir2_sf.c */
 extern xfs_ino_t xfs_dir2_sf_get_parent_ino(struct xfs_dir2_sf_hdr *sfp);