1 files changed, 4 insertions, 53 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 0a6c645fab0a..2ee43b6a4f09 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -52,42 +52,6 @@ noinline void btrfs_set_path_blocking(struct btrfs_path *p)
 	}
 }
 
-/*
- * reset all the locked nodes in the patch to spinning locks.
- *
- * held is used to keep lockdep happy, when lockdep is enabled
- * we set held to a blocking lock before we go around and
- * retake all the spinlocks in the path.  You can safely use NULL
- * for held
- */
-noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
-					struct extent_buffer *held, int held_rw)
-{
-	int i;
-
-	if (held) {
-		btrfs_set_lock_blocking_rw(held, held_rw);
-		if (held_rw == BTRFS_WRITE_LOCK)
-			held_rw = BTRFS_WRITE_LOCK_BLOCKING;
-		else if (held_rw == BTRFS_READ_LOCK)
-			held_rw = BTRFS_READ_LOCK_BLOCKING;
-	}
-	btrfs_set_path_blocking(p);
-
-	for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
-		if (p->nodes[i] && p->locks[i]) {
-			btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]);
-			if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING)
-				p->locks[i] = BTRFS_WRITE_LOCK;
-			else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING)
-				p->locks[i] = BTRFS_READ_LOCK;
-		}
-	}
-
-	if (held)
-		btrfs_clear_lock_blocking_rw(held, held_rw);
-}
-
 /* this also releases the path */
 void btrfs_free_path(struct btrfs_path *p)
 {
@@ -1306,7 +1270,6 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
 		}
 	}
 
-	btrfs_clear_path_blocking(path, NULL, BTRFS_READ_LOCK);
 	btrfs_tree_read_unlock_blocking(eb);
 	free_extent_buffer(eb);
 
@@ -2482,7 +2445,6 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans,
 		btrfs_set_path_blocking(p);
 		reada_for_balance(fs_info, p, level);
 		sret = split_node(trans, root, p, level);
-		btrfs_clear_path_blocking(p, NULL, 0);
 
 		BUG_ON(sret > 0);
 		if (sret) {
@@ -2503,7 +2465,6 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans,
 		btrfs_set_path_blocking(p);
 		reada_for_balance(fs_info, p, level);
 		sret = balance_level(trans, root, p, level);
-		btrfs_clear_path_blocking(p, NULL, 0);
 
 		if (sret) {
 			ret = sret;
@@ -2788,7 +2749,10 @@ again:
 		}
 cow_done:
 		p->nodes[level] = b;
-		btrfs_clear_path_blocking(p, NULL, 0);
+		/*
+		 * Leave path with blocking locks to avoid massive
+		 * lock context switch, this is made on purpose.
+		 */
 
 		/*
 		 * we have a lock on b and as long as we aren't changing
@@ -2870,8 +2834,6 @@ cow_done:
 					if (!err) {
 						btrfs_set_path_blocking(p);
 						btrfs_tree_lock(b);
-						btrfs_clear_path_blocking(p, b,
-								  BTRFS_WRITE_LOCK);
 					}
 					p->locks[level] = BTRFS_WRITE_LOCK;
 				} else {
@@ -2879,8 +2841,6 @@ cow_done:
 					if (!err) {
 						btrfs_set_path_blocking(p);
 						btrfs_tree_read_lock(b);
-						btrfs_clear_path_blocking(p, b,
-								  BTRFS_READ_LOCK);
 					}
 					p->locks[level] = BTRFS_READ_LOCK;
 				}
@@ -2899,7 +2859,6 @@ cow_done:
 				btrfs_set_path_blocking(p);
 				err = split_leaf(trans, root, key,
 						 p, ins_len, ret == 0);
-				btrfs_clear_path_blocking(p, NULL, 0);
 
 				BUG_ON(err > 0);
 				if (err) {
@@ -2970,7 +2929,6 @@ again:
 	while (b) {
 		level = btrfs_header_level(b);
 		p->nodes[level] = b;
-		btrfs_clear_path_blocking(p, NULL, 0);
 
 		/*
 		 * we have a lock on b and as long as we aren't changing
@@ -3016,8 +2974,6 @@ again:
 			if (!err) {
 				btrfs_set_path_blocking(p);
 				btrfs_tree_read_lock(b);
-				btrfs_clear_path_blocking(p, b,
-							  BTRFS_READ_LOCK);
 			}
 			b = tree_mod_log_rewind(fs_info, p, b, time_seq);
 			if (!b) {
@@ -5201,7 +5157,6 @@ find_next_key:
 		path->locks[level - 1] = BTRFS_READ_LOCK;
 		path->nodes[level - 1] = cur;
 		unlock_up(path, level, 1, 0, NULL);
-		btrfs_clear_path_blocking(path, NULL, 0);
 	}
 out:
 	path->keep_locks = keep_locks;
@@ -5786,8 +5741,6 @@ again:
 			if (!ret) {
 				btrfs_set_path_blocking(path);
 				btrfs_tree_read_lock(next);
-				btrfs_clear_path_blocking(path, next,
-							  BTRFS_READ_LOCK);
 			}
 			next_rw_lock = BTRFS_READ_LOCK;
 		}
@@ -5823,8 +5776,6 @@ again:
 			if (!ret) {
 				btrfs_set_path_blocking(path);
 				btrfs_tree_read_lock(next);
-				btrfs_clear_path_blocking(path, next,
-							  BTRFS_READ_LOCK);
 			}
 			next_rw_lock = BTRFS_READ_LOCK;
 		}