fs: move path_put on failure out of ->follow_link

Currently the non-nd_set_link based versions of ->follow_link are expected
to do a path_put(&nd->path) on failure.  This calling convention is unexpected,
undocumented and doesn't match what the nd_set_link-based instances do.

Move the path_put out of the only non-nd_set_link based ->follow_link
instance into the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 4 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 8eaa5ea1c613..3bd5ac1ff018 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1427,16 +1427,20 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
         struct inode *inode = dentry->d_inode;
+        struct path path;
         int error = -EACCES;
 
-        /* We don't need a base pointer in the /proc filesystem */
-        path_put(&nd->path);
-
         /* Are we allowed to snoop on the tasks file descriptors? */
         if (!proc_fd_access_allowed(inode))
                 goto out;
 
-        error = PROC_I(inode)->op.proc_get_link(dentry, &nd->path);
+        error = PROC_I(inode)->op.proc_get_link(dentry, &path);
+        if (error)
+                goto out;
+
+        path_put(&nd->path);
+        nd->path = path;
+        return NULL;
 out:
         return ERR_PTR(error);
 }