2 files changed, 28 insertions, 0 deletions

diff --git a/fs/reiserfs/lock.c b/fs/reiserfs/lock.c
index cdd8d9ef048e..cb1bba3802dd 100644
--- a/fs/reiserfs/lock.c
+++ b/fs/reiserfs/lock.c
@@ -50,6 +50,32 @@ void reiserfs_write_unlock(struct super_block *s)
 }
 
 /*
+ * If we already own the lock, just exit and don't increase the depth.
+ * Useful when we don't want to lock more than once.
+ *
+ * We always return the lock_depth we had before calling
+ * this function.
+ */
+int reiserfs_write_lock_once(struct super_block *s)
+{
+        struct reiserfs_sb_info *sb_i = REISERFS_SB(s);
+
+        if (sb_i->lock_owner != current) {
+                mutex_lock(&sb_i->lock);
+                sb_i->lock_owner = current;
+                return sb_i->lock_depth++;
+        }
+
+        return sb_i->lock_depth;
+}
+
+void reiserfs_write_unlock_once(struct super_block *s, int lock_depth)
+{
+        if (lock_depth == -1)
+                reiserfs_write_unlock(s);
+}
+
+/*
  * Utility function to force a BUG if it is called without the superblock
  * write lock held.  caller is the string printed just before calling BUG()
  */
diff --git a/include/linux/reiserfs_fs.h b/include/linux/reiserfs_fs.h
index e47328f51801..4a2df57c8b1d 100644
--- a/include/linux/reiserfs_fs.h
+++ b/include/linux/reiserfs_fs.h
@@ -59,6 +59,8 @@
  */
 void reiserfs_write_lock(struct super_block *s);
 void reiserfs_write_unlock(struct super_block *s);
+int reiserfs_write_lock_once(struct super_block *s);
+void reiserfs_write_unlock_once(struct super_block *s, int lock_depth);
 
 struct fid;