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, 11 insertions, 11 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c806dfb24e08..4cf5abf77ddf 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -149,18 +149,13 @@ static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,
         return count;
 }
 
-static int get_fs_path(struct task_struct *task, struct path *path, bool root)
+static int get_task_root(struct task_struct *task, struct path *root)
 {
-        struct fs_struct *fs;
         int result = -ENOENT;
 
         task_lock(task);
-        fs = task->fs;
-        if (fs) {
-                read_lock(&fs->lock);
-                *path = root ? fs->root : fs->pwd;
-                path_get(path);
-                read_unlock(&fs->lock);
+        if (task->fs) {
+                get_fs_root(task->fs, root);
                 result = 0;
         }
         task_unlock(task);
@@ -173,7 +168,12 @@ static int proc_cwd_link(struct inode *inode, struct path *path)
         int result = -ENOENT;
 
         if (task) {
-                result = get_fs_path(task, path, 0);
+                task_lock(task);
+                if (task->fs) {
+                        get_fs_pwd(task->fs, path);
+                        result = 0;
+                }
+                task_unlock(task);
                 put_task_struct(task);
         }
         return result;
@@ -185,7 +185,7 @@ static int proc_root_link(struct inode *inode, struct path *path)
         int result = -ENOENT;
 
         if (task) {
-                result = get_fs_path(task, path, 1);
+                result = get_task_root(task, path);
                 put_task_struct(task);
         }
         return result;
@@ -597,7 +597,7 @@ static int mounts_open_common(struct inode *inode, struct file *file,
                                 get_mnt_ns(ns);
                 }
                 rcu_read_unlock();
-                if (ns && get_fs_path(task, &root, 1) == 0)
+                if (ns && get_task_root(task, &root) == 0)
                         ret = 0;
                 put_task_struct(task);
         }