vfs: new helper - d_make_root()

d_alloc_root() with iput() in case of allocation failure...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 18 insertions, 0 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index b209d73f9a98..3c6d3113a255 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1440,6 +1440,23 @@ struct dentry * d_alloc_root(struct inode * root_inode)
 }
 EXPORT_SYMBOL(d_alloc_root);
 
+struct dentry *d_make_root(struct inode *root_inode)
+{
+        struct dentry *res = NULL;
+
+        if (root_inode) {
+                static const struct qstr name = { .name = "/", .len = 1 };
+
+                res = __d_alloc(root_inode->i_sb, &name);
+                if (res)
+                        d_instantiate(res, root_inode);
+                else
+                        iput(root_inode);
+        }
+        return res;
+}
+EXPORT_SYMBOL(d_make_root);
+
 static struct dentry * __d_find_any_alias(struct inode *inode)
 {
         struct dentry *alias;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index ed9f74f6c519..a47bda5f76db 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -249,6 +249,7 @@ extern int d_invalidate(struct dentry *);
 
 /* only used at mount-time */
 extern struct dentry * d_alloc_root(struct inode *);
+extern struct dentry * d_make_root(struct inode *);
 
 /* <clickety>-<click> the ramfs-type tree */
 extern void d_genocide(struct dentry *);