vfs: lock_two_nondirectories: allow directory args

lock_two_nondirectories warned if either of its args was a directory.
Instead just ignore the directory args.  This is needed for locking in
cross rename.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 12 insertions, 13 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 4bcdad3c9361..73779c090f0d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -944,24 +944,22 @@ EXPORT_SYMBOL(unlock_new_inode);
 
 /**
  * lock_two_nondirectories - take two i_mutexes on non-directory objects
+ *
+ * Lock any non-NULL argument that is not a directory.
+ * Zero, one or two objects may be locked by this function.
+ *
  * @inode1: first inode to lock
  * @inode2: second inode to lock
  */
 void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
 {
-        WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
-        if (inode1 == inode2 || !inode2) {
-                mutex_lock(&inode1->i_mutex);
-                return;
-        }
-        WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
-        if (inode1 < inode2) {
+        if (inode1 > inode2)
+                swap(inode1, inode2);
+
+        if (inode1 && !S_ISDIR(inode1->i_mode))
                 mutex_lock(&inode1->i_mutex);
+        if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
                 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
-        } else {
-                mutex_lock(&inode2->i_mutex);
-                mutex_lock_nested(&inode1->i_mutex, I_MUTEX_NONDIR2);
-        }
 }
 EXPORT_SYMBOL(lock_two_nondirectories);
 
@@ -972,8 +970,9 @@ EXPORT_SYMBOL(lock_two_nondirectories);
  */
 void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
 {
-        mutex_unlock(&inode1->i_mutex);
-        if (inode2 && inode2 != inode1)
+        if (inode1 && !S_ISDIR(inode1->i_mode))
+                mutex_unlock(&inode1->i_mutex);
+        if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
                 mutex_unlock(&inode2->i_mutex);
 }
 EXPORT_SYMBOL(unlock_two_nondirectories);