---

yaml
---
r: 131442
b: refs/heads/master
c: 4008c04
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3f3420df505e47751ef76a652b5cb660e5360d6f
+refs/heads/master: 4008c04a07c73ec3cb1be4c1391d2159a8f75d6d

trunk/fs/btrfs/ctree.c

@@ -62,14 +62,38 @@ 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)
+noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
+					struct extent_buffer *held)
 {
 	int i;
-	for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/* lockdep really cares that we take all of these spinlocks
+	 * in the right order.  If any of the locks in the path are not
+	 * currently blocking, it is going to complain.  So, make really
+	 * really sure by forcing the path to blocking before we clear
+	 * the path blocking.
+	 */
+	if (held)
+		btrfs_set_lock_blocking(held);
+	btrfs_set_path_blocking(p);
+#endif
+
+	for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
 		if (p->nodes[i] && p->locks[i])
 			btrfs_clear_lock_blocking(p->nodes[i]);
 	}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	if (held)
+		btrfs_clear_lock_blocking(held);
+#endif
 }
 
 /* this also releases the path */
@@ -279,7 +303,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 						  trans->transid, level, &ins);
 		BUG_ON(ret);
 		cow = btrfs_init_new_buffer(trans, root, prealloc_dest,
-					    buf->len);
+					    buf->len, level);
 	} else {
 		cow = btrfs_alloc_free_block(trans, root, buf->len,
 					     parent_start,
@@ -1559,7 +1583,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 		if (!p->skip_locking)
 			p->locks[level] = 1;
 
-		btrfs_clear_path_blocking(p);
+		btrfs_clear_path_blocking(p, NULL);
 
 		/*
 		 * we have a lock on b and as long as we aren't changing
@@ -1598,7 +1622,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 
 				btrfs_set_path_blocking(p);
 				sret = split_node(trans, root, p, level);
-				btrfs_clear_path_blocking(p);
+				btrfs_clear_path_blocking(p, NULL);
 
 				BUG_ON(sret > 0);
 				if (sret) {
@@ -1618,7 +1642,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 
 				btrfs_set_path_blocking(p);
 				sret = balance_level(trans, root, p, level);
-				btrfs_clear_path_blocking(p);
+				btrfs_clear_path_blocking(p, NULL);
 
 				if (sret) {
 					ret = sret;
@@ -1681,13 +1705,13 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 			if (!p->skip_locking) {
 				int lret;
 
-				btrfs_clear_path_blocking(p);
+				btrfs_clear_path_blocking(p, NULL);
 				lret = btrfs_try_spin_lock(b);
 
 				if (!lret) {
 					btrfs_set_path_blocking(p);
 					btrfs_tree_lock(b);
-					btrfs_clear_path_blocking(p);
+					btrfs_clear_path_blocking(p, b);
 				}
 			}
 		} else {
@@ -1699,7 +1723,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 				btrfs_set_path_blocking(p);
 				sret = split_leaf(trans, root, key,
 						      p, ins_len, ret == 0);
-				btrfs_clear_path_blocking(p);
+				btrfs_clear_path_blocking(p, NULL);
 
 				BUG_ON(sret > 0);
 				if (sret) {
@@ -3919,7 +3943,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
 				btrfs_release_path(root, path);
 				goto again;
 			} else {
-				btrfs_clear_path_blocking(path);
 				goto out;
 			}
 		}
@@ -3939,7 +3962,7 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
 		path->locks[level - 1] = 1;
 		path->nodes[level - 1] = cur;
 		unlock_up(path, level, 1);
-		btrfs_clear_path_blocking(path);
+		btrfs_clear_path_blocking(path, NULL);
 	}
 out:
 	if (ret == 0)

trunk/fs/btrfs/ctree.h

@@ -43,11 +43,7 @@ struct btrfs_ordered_sum;
 
 #define BTRFS_ACL_NOT_CACHED    ((void *)-1)
 
-#ifdef CONFIG_LOCKDEP
-# define BTRFS_MAX_LEVEL 7
-#else
-# define BTRFS_MAX_LEVEL 8
-#endif
+#define BTRFS_MAX_LEVEL 8
 
 /* holds pointers to all of the tree roots */
 #define BTRFS_ROOT_TREE_OBJECTID 1ULL
@@ -1715,7 +1711,8 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 					     u64 empty_size);
 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
 					    struct btrfs_root *root,
-					    u64 bytenr, u32 blocksize);
+					    u64 bytenr, u32 blocksize,
+					    int level);
 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 		       struct btrfs_root *root,
 		       u64 num_bytes, u64 parent, u64 min_bytes,
@@ -1835,7 +1832,6 @@ void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
 struct btrfs_path *btrfs_alloc_path(void);
 void btrfs_free_path(struct btrfs_path *p);
 void btrfs_set_path_blocking(struct btrfs_path *p);
-void btrfs_clear_path_blocking(struct btrfs_path *p);
 void btrfs_unlock_up_safe(struct btrfs_path *p, int level);
 
 int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,

trunk/fs/btrfs/disk-io.c

@@ -75,6 +75,40 @@ struct async_submit_bio {
 	struct btrfs_work work;
 };
 
+/* These are used to set the lockdep class on the extent buffer locks.
+ * The class is set by the readpage_end_io_hook after the buffer has
+ * passed csum validation but before the pages are unlocked.
+ *
+ * The lockdep class is also set by btrfs_init_new_buffer on freshly
+ * allocated blocks.
+ *
+ * The class is based on the level in the tree block, which allows lockdep
+ * to know that lower nodes nest inside the locks of higher nodes.
+ *
+ * We also add a check to make sure the highest level of the tree is
+ * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
+ * code needs update as well.
+ */
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# if BTRFS_MAX_LEVEL != 8
+#  error
+# endif
+static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
+static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
+	/* leaf */
+	"btrfs-extent-00",
+	"btrfs-extent-01",
+	"btrfs-extent-02",
+	"btrfs-extent-03",
+	"btrfs-extent-04",
+	"btrfs-extent-05",
+	"btrfs-extent-06",
+	"btrfs-extent-07",
+	/* highest possible level */
+	"btrfs-extent-08",
+};
+#endif
+
 /*
  * extents on the btree inode are pretty simple, there's one extent
  * that covers the entire device
@@ -347,6 +381,15 @@ static int check_tree_block_fsid(struct btrfs_root *root,
 	return ret;
 }
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
+{
+	lockdep_set_class_and_name(&eb->lock,
+			   &btrfs_eb_class[level],
+			   btrfs_eb_name[level]);
+}
+#endif
+
 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 			       struct extent_state *state)
 {
@@ -392,6 +435,8 @@ static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 	}
 	found_level = btrfs_header_level(eb);
 
+	btrfs_set_buffer_lockdep_class(eb, found_level);
+
 	ret = csum_tree_block(root, eb, 1);
 	if (ret)
 		ret = -EIO;
@@ -1777,7 +1822,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	ret = find_and_setup_root(tree_root, fs_info,
 				  BTRFS_DEV_TREE_OBJECTID, dev_root);
 	dev_root->track_dirty = 1;
-
 	if (ret)
 		goto fail_extent_root;
 

trunk/fs/btrfs/disk-io.h

@@ -101,4 +101,14 @@ int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
 		       struct btrfs_root *root);
 int btree_lock_page_hook(struct page *page);
+
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level);
+#else
+static inline void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb,
+						 int level)
+{
+}
+#endif
 #endif

trunk/fs/btrfs/extent-tree.c

@@ -3416,14 +3416,16 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 
 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
 					    struct btrfs_root *root,
-					    u64 bytenr, u32 blocksize)
+					    u64 bytenr, u32 blocksize,
+					    int level)
 {
 	struct extent_buffer *buf;
 
 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 	btrfs_set_header_generation(buf, trans->transid);
+	btrfs_set_buffer_lockdep_class(buf, level);
 	btrfs_tree_lock(buf);
 	clean_tree_block(trans, root, buf);
 
@@ -3467,7 +3469,8 @@ struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 		return ERR_PTR(ret);
 	}
 
-	buf = btrfs_init_new_buffer(trans, root, ins.objectid, blocksize);
+	buf = btrfs_init_new_buffer(trans, root, ins.objectid,
+				    blocksize, level);
 	return buf;
 }
 

trunk/fs/btrfs/locking.c

@@ -25,21 +25,10 @@
 #include "extent_io.h"
 #include "locking.h"
 
-/*
- * btrfs_header_level() isn't free, so don't call it when lockdep isn't
- * on
- */
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-static inline void spin_nested(struct extent_buffer *eb)
-{
-	spin_lock_nested(&eb->lock, BTRFS_MAX_LEVEL - btrfs_header_level(eb));
-}
-#else
 static inline void spin_nested(struct extent_buffer *eb)
 {
 	spin_lock(&eb->lock);
 }
-#endif
 
 /*
  * Setting a lock to blocking will drop the spinlock and set the

trunk/fs/btrfs/volumes.c

@@ -3102,6 +3102,8 @@ int btrfs_read_sys_array(struct btrfs_root *root)
 	if (!sb)
 		return -ENOMEM;
 	btrfs_set_buffer_uptodate(sb);
+	btrfs_set_buffer_lockdep_class(sb, 0);
+
 	write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
 	array_size = btrfs_super_sys_array_size(super_copy);