vfs: add helpers to get root and pwd

Add three helpers that retrieve a refcounted copy of the root and cwd
from the supplied fs_struct.

 get_fs_root()
 get_fs_pwd()
 get_fs_root_and_pwd()

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 12 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 13ff4abdbdca..17ea76bf2fbe 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -483,13 +483,8 @@ ok:
 
 static __always_inline void set_root(struct nameidata *nd)
 {
-        if (!nd->root.mnt) {
-                struct fs_struct *fs = current->fs;
-                read_lock(&fs->lock);
-                nd->root = fs->root;
-                path_get(&nd->root);
-                read_unlock(&fs->lock);
-        }
+        if (!nd->root.mnt)
+                get_fs_root(current->fs, &nd->root);
 }
 
 static int link_path_walk(const char *, struct nameidata *);
@@ -1015,11 +1010,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct namei
                 nd->path = nd->root;
                 path_get(&nd->root);
         } else if (dfd == AT_FDCWD) {
-                struct fs_struct *fs = current->fs;
-                read_lock(&fs->lock);
-                nd->path = fs->pwd;
-                path_get(&fs->pwd);
-                read_unlock(&fs->lock);
+                get_fs_pwd(current->fs, &nd->path);
         } else {
                 struct dentry *dentry;