Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: hold trans_mutex when using btrfs_record_root_in_trans
  Btrfs: make a lockdep class for the extent buffer locks
  Btrfs: fs/btrfs/volumes.c: remove useless kzalloc
  Btrfs: remove unused code in split_state()
  Btrfs: remove btrfs_init_path
  Btrfs: balance_level checks !child after access
  Btrfs: Avoid using __GFP_HIGHMEM with slab allocator
  Btrfs: don't clean old snapshots on sync(1)
  Btrfs: use larger metadata clusters in ssd mode
  Btrfs: process mount options on mount -o remount,
  Btrfs: make sure all pending extent operations are complete

fs/btrfs/ctree.c

@@ -38,19 +38,12 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
 static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		   struct btrfs_path *path, int level, int slot);
 
-inline void btrfs_init_path(struct btrfs_path *p)
-{
-	memset(p, 0, sizeof(*p));
-}
-
 struct btrfs_path *btrfs_alloc_path(void)
 {
 	struct btrfs_path *path;
-	path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
-	if (path) {
-		btrfs_init_path(path);
+	path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
+	if (path)
 		path->reada = 1;
-	}
 	return path;
 }
 
@@ -69,14 +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 */
@@ -286,7 +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,
@@ -917,9 +934,9 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 
 		/* promote the child to a root */
 		child = read_node_slot(root, mid, 0);
+		BUG_ON(!child);
 		btrfs_tree_lock(child);
 		btrfs_set_lock_blocking(child);
-		BUG_ON(!child);
 		ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0);
 		BUG_ON(ret);
 
@@ -1566,7 +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
@@ -1605,7 +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) {
@@ -1625,7 +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;
@@ -1688,13 +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 {
@@ -1706,7 +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) {
@@ -3926,7 +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;
 			}
 		}
@@ -3946,7 +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)

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,
@@ -1834,9 +1831,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 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_init_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,

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;
 

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

fs/btrfs/extent-tree.c

@@ -1323,8 +1323,25 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root)
 {
-	finish_current_insert(trans, root->fs_info->extent_root, 1);
-	del_pending_extents(trans, root->fs_info->extent_root, 1);
+	u64 start;
+	u64 end;
+	int ret;
+
+	while(1) {
+		finish_current_insert(trans, root->fs_info->extent_root, 1);
+		del_pending_extents(trans, root->fs_info->extent_root, 1);
+
+		/* is there more work to do? */
+		ret = find_first_extent_bit(&root->fs_info->pending_del,
+					    0, &start, &end, EXTENT_WRITEBACK);
+		if (!ret)
+			continue;
+		ret = find_first_extent_bit(&root->fs_info->extent_ins,
+					    0, &start, &end, EXTENT_WRITEBACK);
+		if (!ret)
+			continue;
+		break;
+	}
 	return 0;
 }
 
@@ -2211,13 +2228,12 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 	u64 end;
 	u64 priv;
 	u64 search = 0;
-	u64 skipped = 0;
 	struct btrfs_fs_info *info = extent_root->fs_info;
 	struct btrfs_path *path;
 	struct pending_extent_op *extent_op, *tmp;
 	struct list_head insert_list, update_list;
 	int ret;
-	int num_inserts = 0, max_inserts;
+	int num_inserts = 0, max_inserts, restart = 0;
 
 	path = btrfs_alloc_path();
 	INIT_LIST_HEAD(&insert_list);
@@ -2233,19 +2249,19 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 		ret = find_first_extent_bit(&info->extent_ins, search, &start,
 					    &end, EXTENT_WRITEBACK);
 		if (ret) {
-			if (skipped && all && !num_inserts &&
+			if (restart && !num_inserts &&
 			    list_empty(&update_list)) {
-				skipped = 0;
+				restart = 0;
 				search = 0;
 				continue;
 			}
-			mutex_unlock(&info->extent_ins_mutex);
 			break;
 		}
 
 		ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
 		if (!ret) {
-			skipped = 1;
+			if (all)
+				restart = 1;
 			search = end + 1;
 			if (need_resched()) {
 				mutex_unlock(&info->extent_ins_mutex);
@@ -2264,7 +2280,7 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 			list_add_tail(&extent_op->list, &insert_list);
 			search = end + 1;
 			if (num_inserts == max_inserts) {
-				mutex_unlock(&info->extent_ins_mutex);
+				restart = 1;
 				break;
 			}
 		} else if (extent_op->type == PENDING_BACKREF_UPDATE) {
@@ -2280,7 +2296,6 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 	 * somebody marked this thing for deletion then just unlock it and be
 	 * done, the free_extents will handle it
 	 */
-	mutex_lock(&info->extent_ins_mutex);
 	list_for_each_entry_safe(extent_op, tmp, &update_list, list) {
 		clear_extent_bits(&info->extent_ins, extent_op->bytenr,
 				  extent_op->bytenr + extent_op->num_bytes - 1,
@@ -2302,6 +2317,10 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 	if (!list_empty(&update_list)) {
 		ret = update_backrefs(trans, extent_root, path, &update_list);
 		BUG_ON(ret);
+
+		/* we may have COW'ed new blocks, so lets start over */
+		if (all)
+			restart = 1;
 	}
 
 	/*
@@ -2309,9 +2328,9 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 	 * need to make sure everything is cleaned then reset everything and
 	 * go back to the beginning
 	 */
-	if (!num_inserts && all && skipped) {
+	if (!num_inserts && restart) {
 		search = 0;
-		skipped = 0;
+		restart = 0;
 		INIT_LIST_HEAD(&update_list);
 		INIT_LIST_HEAD(&insert_list);
 		goto again;
@@ -2368,27 +2387,19 @@ static int finish_current_insert(struct btrfs_trans_handle *trans,
 	BUG_ON(ret);
 
 	/*
-	 * if we broke out of the loop in order to insert stuff because we hit
-	 * the maximum number of inserts at a time we can handle, then loop
-	 * back and pick up where we left off
+	 * if restart is set for whatever reason we need to go back and start
+	 * searching through the pending list again.
+	 *
+	 * We just inserted some extents, which could have resulted in new
+	 * blocks being allocated, which would result in new blocks needing
+	 * updates, so if all is set we _must_ restart to get the updated
+	 * blocks.
 	 */
-	if (num_inserts == max_inserts) {
-		INIT_LIST_HEAD(&insert_list);
-		INIT_LIST_HEAD(&update_list);
-		num_inserts = 0;
-		goto again;
-	}
-
-	/*
-	 * again, if we need to make absolutely sure there are no more pending
-	 * extent operations left and we know that we skipped some, go back to
-	 * the beginning and do it all again
-	 */
-	if (all && skipped) {
+	if (restart || all) {
 		INIT_LIST_HEAD(&insert_list);
 		INIT_LIST_HEAD(&update_list);
 		search = 0;
-		skipped = 0;
+		restart = 0;
 		num_inserts = 0;
 		goto again;
 	}
@@ -2709,6 +2720,8 @@ static int del_pending_extents(struct btrfs_trans_handle *trans,
 		goto again;
 	}
 
+	if (!err)
+		finish_current_insert(trans, extent_root, 0);
 	return err;
 }
 
@@ -2859,7 +2872,8 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
 
 	if (data & BTRFS_BLOCK_GROUP_METADATA) {
 		last_ptr = &root->fs_info->last_alloc;
-		empty_cluster = 64 * 1024;
+		if (!btrfs_test_opt(root, SSD))
+			empty_cluster = 64 * 1024;
 	}
 
 	if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
@@ -3402,7 +3416,8 @@ 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;
 
@@ -3410,6 +3425,7 @@ struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
 	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);
 
@@ -3453,7 +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;
 }
 
@@ -5641,7 +5658,9 @@ static noinline int relocate_one_extent(struct btrfs_root *extent_root,
 			prev_block = block_start;
 		}
 
+		mutex_lock(&extent_root->fs_info->trans_mutex);
 		btrfs_record_root_in_trans(found_root);
+		mutex_unlock(&extent_root->fs_info->trans_mutex);
 		if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
 			/*
 			 * try to update data extent references while

fs/btrfs/extent_io.c

@@ -415,8 +415,6 @@ static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
 
 	node = tree_insert(&tree->state, prealloc->end, &prealloc->rb_node);
 	if (node) {
-		struct extent_state *found;
-		found = rb_entry(node, struct extent_state, rb_node);
 		free_extent_state(prealloc);
 		return -EEXIST;
 	}

fs/btrfs/inode-map.c

@@ -84,7 +84,6 @@ int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
 	search_key.type = 0;
 	search_key.offset = 0;
 
-	btrfs_init_path(path);
 	start_found = 0;
 	ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
 	if (ret < 0)

fs/btrfs/inode.c

@@ -2531,8 +2531,6 @@ noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 	key.offset = (u64)-1;
 	key.type = (u8)-1;
 
-	btrfs_init_path(path);
-
 search_again:
 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 	if (ret < 0)
@@ -4263,7 +4261,7 @@ static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
 {
 	if (PageWriteback(page) || PageDirty(page))
 		return 0;
-	return __btrfs_releasepage(page, gfp_flags);
+	return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
 }
 
 static void btrfs_invalidatepage(struct page *page, unsigned long offset)

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

fs/btrfs/super.c

@@ -379,7 +379,6 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
 	btrfs_start_delalloc_inodes(root);
 	btrfs_wait_ordered_extents(root, 0);
 
-	btrfs_clean_old_snapshots(root);
 	trans = btrfs_start_transaction(root, 1);
 	ret = btrfs_commit_transaction(trans, root);
 	sb->s_dirt = 0;
@@ -511,6 +510,10 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 	struct btrfs_root *root = btrfs_sb(sb);
 	int ret;
 
+	ret = btrfs_parse_options(root, data);
+	if (ret)
+		return -EINVAL;
+
 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
 		return 0;
 

fs/btrfs/transaction.c

@@ -688,7 +688,9 @@ static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
 		num_bytes -= btrfs_root_used(&dirty->root->root_item);
 		bytes_used = btrfs_root_used(&root->root_item);
 		if (num_bytes) {
+			mutex_lock(&root->fs_info->trans_mutex);
 			btrfs_record_root_in_trans(root);
+			mutex_unlock(&root->fs_info->trans_mutex);
 			btrfs_set_root_used(&root->root_item,
 					    bytes_used - num_bytes);
 		}

fs/btrfs/tree-log.c

@@ -2832,7 +2832,9 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
 		BUG_ON(!wc.replay_dest);
 
 		wc.replay_dest->log_root = log;
+		mutex_lock(&fs_info->trans_mutex);
 		btrfs_record_root_in_trans(wc.replay_dest);
+		mutex_unlock(&fs_info->trans_mutex);
 		ret = walk_log_tree(trans, log, &wc);
 		BUG_ON(ret);
 

fs/btrfs/volumes.c

@@ -2894,10 +2894,6 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
 		free_extent_map(em);
 	}
 
-	map = kzalloc(sizeof(*map), GFP_NOFS);
-	if (!map)
-		return -ENOMEM;
-
 	em = alloc_extent_map(GFP_NOFS);
 	if (!em)
 		return -ENOMEM;
@@ -3106,6 +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);