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, 12 deletions

diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index 72d4d0042826..727caedcdd92 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -552,7 +552,6 @@ static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
  */
 static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
 {
-        struct fs_struct *fs;
         struct path path;
         const struct cred *saved_cred;
         int ret;
@@ -573,11 +572,7 @@ static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
         }
 
         /* extract the directory dentry from the cwd */
-        fs = current->fs;
-        read_lock(&fs->lock);
-        path = fs->pwd;
-        path_get(&path);
-        read_unlock(&fs->lock);
+        get_fs_pwd(current->fs, &path);
 
         if (!S_ISDIR(path.dentry->d_inode->i_mode))
                 goto notdir;
@@ -629,7 +624,6 @@ inval:
  */
 static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
 {
-        struct fs_struct *fs;
         struct path path;
         const struct cred *saved_cred;
         int ret;
@@ -650,11 +644,7 @@ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
         }
 
         /* extract the directory dentry from the cwd */
-        fs = current->fs;
-        read_lock(&fs->lock);
-        path = fs->pwd;
-        path_get(&path);
-        read_unlock(&fs->lock);
+        get_fs_pwd(current->fs, &path);
 
         if (!S_ISDIR(path.dentry->d_inode->i_mode))
                 goto notdir;