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, 2 insertions, 10 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 9f2c13417969..995d08069d26 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2014,10 +2014,7 @@ char *d_path(const struct path *path, char *buf, int buflen)
         if (path->dentry->d_op && path->dentry->d_op->d_dname)
                 return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
 
-        read_lock(&current->fs->lock);
-        root = current->fs->root;
-        path_get(&root);
-        read_unlock(&current->fs->lock);
+        get_fs_root(current->fs, &root);
         spin_lock(&dcache_lock);
         tmp = root;
         res = __d_path(path, &tmp, buf, buflen);
@@ -2129,12 +2126,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
         if (!page)
                 return -ENOMEM;
 
-        read_lock(&current->fs->lock);
-        pwd = current->fs->pwd;
-        path_get(&pwd);
-        root = current->fs->root;
-        path_get(&root);
-        read_unlock(&current->fs->lock);
+        get_fs_root_and_pwd(current->fs, &root, &pwd);
 
         error = -ENOENT;
         spin_lock(&dcache_lock);