1 files changed, 17 insertions, 6 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 8af24da983b1..270655da11d1 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1395,7 +1395,8 @@ static noinline int reada_for_balance(struct btrfs_root *root,
  * if lowest_unlock is 1, level 0 won't be unlocked
  */
 static noinline void unlock_up(struct btrfs_path *path, int level,
-                               int lowest_unlock)
+                               int lowest_unlock, int min_write_lock_level,
+                               int *write_lock_level)
 {
         int i;
         int skip_level = level;
@@ -1427,6 +1428,11 @@ static noinline void unlock_up(struct btrfs_path *path, int level,
                 if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
                         btrfs_tree_unlock_rw(t, path->locks[i]);
                         path->locks[i] = 0;
+                        if (write_lock_level &&
+                            i > min_write_lock_level &&
+                            i <= *write_lock_level) {
+                                *write_lock_level = i - 1;
+                        }
                 }
         }
 }
@@ -1650,6 +1656,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
         /* everything at write_lock_level or lower must be write locked */
         int write_lock_level = 0;
         u8 lowest_level = 0;
+        int min_write_lock_level;
 
         lowest_level = p->lowest_level;
         WARN_ON(lowest_level && ins_len > 0);
@@ -1677,6 +1684,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
         if (cow && (p->keep_locks || p->lowest_level))
                 write_lock_level = BTRFS_MAX_LEVEL;
 
+        min_write_lock_level = write_lock_level;
+
 again:
         /*
          * we try very hard to do read locks on the root
@@ -1808,7 +1817,8 @@ cow_done:
                                 goto again;
                         }
 
-                        unlock_up(p, level, lowest_unlock);
+                        unlock_up(p, level, lowest_unlock,
+                                  min_write_lock_level, &write_lock_level);
 
                         if (level == lowest_level) {
                                 if (dec)
@@ -1870,7 +1880,8 @@ cow_done:
                                 }
                         }
                         if (!p->search_for_split)
-                                unlock_up(p, level, lowest_unlock);
+                                unlock_up(p, level, lowest_unlock,
+                                          min_write_lock_level, &write_lock_level);
                         goto done;
                 }
         }
@@ -4108,7 +4119,7 @@ find_next_key:
                 path->slots[level] = slot;
                 if (level == path->lowest_level) {
                         ret = 0;
-                        unlock_up(path, level, 1);
+                        unlock_up(path, level, 1, 0, NULL);
                         goto out;
                 }
                 btrfs_set_path_blocking(path);
@@ -4119,7 +4130,7 @@ find_next_key:
 
                 path->locks[level - 1] = BTRFS_READ_LOCK;
                 path->nodes[level - 1] = cur;
-                unlock_up(path, level, 1);
+                unlock_up(path, level, 1, 0, NULL);
                 btrfs_clear_path_blocking(path, NULL, 0);
         }
 out:
@@ -4355,7 +4366,7 @@ again:
         }
         ret = 0;
 done:
-        unlock_up(path, 0, 1);
+        unlock_up(path, 0, 1, 0, NULL);
         path->leave_spinning = old_spinning;
         if (!old_spinning)
                 btrfs_set_path_blocking(path);