xfs: combine xfs_dir_canenter into xfs_dir_createname

xfs_dir_canenter and xfs_dir_createname are
almost identical.

Fold the former into the latter, with a helpful
wrapper for the former.  If createname is called without
an inode number, it now only checks for space, and does
not actually add the entry.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_dir2.c

@@ -237,7 +237,8 @@ xfs_dir_init(
 }
 
 /*
-  Enter a name in a directory.
+ * Enter a name in a directory, or check for available space.
+ * If inum is 0, only the available space test is performed.
  */
 int
 xfs_dir_createname(
@@ -254,10 +255,12 @@ xfs_dir_createname(
 	int			v;		/* type-checking value */
 
 	ASSERT(S_ISDIR(dp->i_d.di_mode));
-	rval = xfs_dir_ino_validate(tp->t_mountp, inum);
-	if (rval)
-		return rval;
-	XFS_STATS_INC(xs_dir_create);
+	if (inum) {
+		rval = xfs_dir_ino_validate(tp->t_mountp, inum);
+		if (rval)
+			return rval;
+		XFS_STATS_INC(xs_dir_create);
+	}
 
 	args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
 	if (!args)
@@ -276,6 +279,8 @@ xfs_dir_createname(
 	args->whichfork = XFS_DATA_FORK;
 	args->trans = tp;
 	args->op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
+	if (!inum)
+		args->op_flags |= XFS_DA_OP_JUSTCHECK;
 
 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
 		rval = xfs_dir2_sf_addname(args);
@@ -542,50 +547,7 @@ xfs_dir_canenter(
 	xfs_inode_t	*dp,
 	struct xfs_name	*name)		/* name of entry to add */
 {
-	struct xfs_da_args *args;
-	int		rval;
-	int		v;		/* type-checking value */
-
-	ASSERT(S_ISDIR(dp->i_d.di_mode));
-
-	args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
-	if (!args)
-		return -ENOMEM;
-
-	args->geo = dp->i_mount->m_dir_geo;
-	args->name = name->name;
-	args->namelen = name->len;
-	args->filetype = name->type;
-	args->hashval = dp->i_mount->m_dirnameops->hashname(name);
-	args->dp = dp;
-	args->whichfork = XFS_DATA_FORK;
-	args->trans = tp;
-	args->op_flags = XFS_DA_OP_JUSTCHECK | XFS_DA_OP_ADDNAME |
-							XFS_DA_OP_OKNOENT;
-
-	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
-		rval = xfs_dir2_sf_addname(args);
-		goto out_free;
-	}
-
-	rval = xfs_dir2_isblock(args, &v);
-	if (rval)
-		goto out_free;
-	if (v) {
-		rval = xfs_dir2_block_addname(args);
-		goto out_free;
-	}
-
-	rval = xfs_dir2_isleaf(args, &v);
-	if (rval)
-		goto out_free;
-	if (v)
-		rval = xfs_dir2_leaf_addname(args);
-	else
-		rval = xfs_dir2_node_addname(args);
-out_free:
-	kmem_free(args);
-	return rval;
+	return xfs_dir_createname(tp, dp, name, 0, NULL, NULL, 0);
 }
 
 /*