git simplify nilfs check for busy subtree

Reviewed-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/nilfs2/super.c

@@ -994,23 +994,16 @@ static int nilfs_attach_snapshot(struct super_block *s, __u64 cno,
 	return ret;
 }
 
-static int nilfs_tree_was_touched(struct dentry *root_dentry)
-{
-	return d_count(root_dentry) > 1;
-}
-
 /**
- * nilfs_try_to_shrink_tree() - try to shrink dentries of a checkpoint
+ * nilfs_tree_is_busy() - try to shrink dentries of a checkpoint
  * @root_dentry: root dentry of the tree to be shrunk
  *
  * This function returns true if the tree was in-use.
  */
-static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
+static bool nilfs_tree_is_busy(struct dentry *root_dentry)
 {
-	if (have_submounts(root_dentry))
-		return true;
 	shrink_dcache_parent(root_dentry);
-	return nilfs_tree_was_touched(root_dentry);
+	return d_count(root_dentry) > 1;
 }
 
 int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
@@ -1034,8 +1027,7 @@ int nilfs_checkpoint_is_mounted(struct super_block *sb, __u64 cno)
 		if (inode) {
 			dentry = d_find_alias(inode);
 			if (dentry) {
-				if (nilfs_tree_was_touched(dentry))
-					ret = nilfs_try_to_shrink_tree(dentry);
+				ret = nilfs_tree_is_busy(dentry);
 				dput(dentry);
 			}
 			iput(inode);
@@ -1331,11 +1323,8 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 
 		s->s_flags |= MS_ACTIVE;
 	} else if (!sd.cno) {
-		int busy = false;
-
-		if (nilfs_tree_was_touched(s->s_root)) {
-			busy = nilfs_try_to_shrink_tree(s->s_root);
-			if (busy && (flags ^ s->s_flags) & MS_RDONLY) {
+		if (nilfs_tree_is_busy(s->s_root)) {
+			if ((flags ^ s->s_flags) & MS_RDONLY) {
 				printk(KERN_ERR "NILFS: the device already "
 				       "has a %s mount.\n",
 				       (s->s_flags & MS_RDONLY) ?
@@ -1343,8 +1332,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 				err = -EBUSY;
 				goto failed_super;
 			}
-		}
-		if (!busy) {
+		} else {
 			/*
 			 * Try remount to setup mount states if the current
 			 * tree is not mounted and only snapshots use this sb.