1 files changed, 144 insertions, 22 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index dcaae3616728..a605d4e2f2bc 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -76,6 +76,32 @@ void btrfs_put_transaction(struct btrfs_transaction *transaction)
 	}
 }
 
+static void clear_btree_io_tree(struct extent_io_tree *tree)
+{
+	spin_lock(&tree->lock);
+	while (!RB_EMPTY_ROOT(&tree->state)) {
+		struct rb_node *node;
+		struct extent_state *state;
+
+		node = rb_first(&tree->state);
+		state = rb_entry(node, struct extent_state, rb_node);
+		rb_erase(&state->rb_node, &tree->state);
+		RB_CLEAR_NODE(&state->rb_node);
+		/*
+		 * btree io trees aren't supposed to have tasks waiting for
+		 * changes in the flags of extent states ever.
+		 */
+		ASSERT(!waitqueue_active(&state->wq));
+		free_extent_state(state);
+		if (need_resched()) {
+			spin_unlock(&tree->lock);
+			cond_resched();
+			spin_lock(&tree->lock);
+		}
+	}
+	spin_unlock(&tree->lock);
+}
+
 static noinline void switch_commit_roots(struct btrfs_transaction *trans,
 					 struct btrfs_fs_info *fs_info)
 {
@@ -89,6 +115,7 @@ static noinline void switch_commit_roots(struct btrfs_transaction *trans,
 		root->commit_root = btrfs_root_node(root);
 		if (is_fstree(root->objectid))
 			btrfs_unpin_free_ino(root);
+		clear_btree_io_tree(&root->dirty_log_pages);
 	}
 	up_write(&fs_info->commit_root_sem);
 }
@@ -220,6 +247,7 @@ loop:
 	INIT_LIST_HEAD(&cur_trans->pending_snapshots);
 	INIT_LIST_HEAD(&cur_trans->pending_chunks);
 	INIT_LIST_HEAD(&cur_trans->switch_commits);
+	INIT_LIST_HEAD(&cur_trans->pending_ordered);
 	list_add_tail(&cur_trans->list, &fs_info->trans_list);
 	extent_io_tree_init(&cur_trans->dirty_pages,
 			     fs_info->btree_inode->i_mapping);
@@ -488,6 +516,7 @@ again:
 	h->sync = false;
 	INIT_LIST_HEAD(&h->qgroup_ref_list);
 	INIT_LIST_HEAD(&h->new_bgs);
+	INIT_LIST_HEAD(&h->ordered);
 
 	smp_mb();
 	if (cur_trans->state >= TRANS_STATE_BLOCKED &&
@@ -719,6 +748,12 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 	if (!list_empty(&trans->new_bgs))
 		btrfs_create_pending_block_groups(trans, root);
 
+	if (!list_empty(&trans->ordered)) {
+		spin_lock(&info->trans_lock);
+		list_splice(&trans->ordered, &cur_trans->pending_ordered);
+		spin_unlock(&info->trans_lock);
+	}
+
 	trans->delayed_ref_updates = 0;
 	if (!trans->sync) {
 		must_run_delayed_refs =
@@ -828,17 +863,39 @@ int btrfs_write_marked_extents(struct btrfs_root *root,
 
 	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
 				      mark, &cached_state)) {
-		convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
-				   mark, &cached_state, GFP_NOFS);
-		cached_state = NULL;
-		err = filemap_fdatawrite_range(mapping, start, end);
+		bool wait_writeback = false;
+
+		err = convert_extent_bit(dirty_pages, start, end,
+					 EXTENT_NEED_WAIT,
+					 mark, &cached_state, GFP_NOFS);
+		/*
+		 * convert_extent_bit can return -ENOMEM, which is most of the
+		 * time a temporary error. So when it happens, ignore the error
+		 * and wait for writeback of this range to finish - because we
+		 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
+		 * to btrfs_wait_marked_extents() would not know that writeback
+		 * for this range started and therefore wouldn't wait for it to
+		 * finish - we don't want to commit a superblock that points to
+		 * btree nodes/leafs for which writeback hasn't finished yet
+		 * (and without errors).
+		 * We cleanup any entries left in the io tree when committing
+		 * the transaction (through clear_btree_io_tree()).
+		 */
+		if (err == -ENOMEM) {
+			err = 0;
+			wait_writeback = true;
+		}
+		if (!err)
+			err = filemap_fdatawrite_range(mapping, start, end);
 		if (err)
 			werr = err;
+		else if (wait_writeback)
+			werr = filemap_fdatawait_range(mapping, start, end);
+		free_extent_state(cached_state);
+		cached_state = NULL;
 		cond_resched();
 		start = end + 1;
 	}
-	if (err)
-		werr = err;
 	return werr;
 }
 
@@ -862,11 +919,25 @@ int btrfs_wait_marked_extents(struct btrfs_root *root,
 
 	while (!find_first_extent_bit(dirty_pages, start, &start, &end,
 				      EXTENT_NEED_WAIT, &cached_state)) {
-		clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
-				 0, 0, &cached_state, GFP_NOFS);
-		err = filemap_fdatawait_range(mapping, start, end);
+		/*
+		 * Ignore -ENOMEM errors returned by clear_extent_bit().
+		 * When committing the transaction, we'll remove any entries
+		 * left in the io tree. For a log commit, we don't remove them
+		 * after committing the log because the tree can be accessed
+		 * concurrently - we do it only at transaction commit time when
+		 * it's safe to do it (through clear_btree_io_tree()).
+		 */
+		err = clear_extent_bit(dirty_pages, start, end,
+				       EXTENT_NEED_WAIT,
+				       0, 0, &cached_state, GFP_NOFS);
+		if (err == -ENOMEM)
+			err = 0;
+		if (!err)
+			err = filemap_fdatawait_range(mapping, start, end);
 		if (err)
 			werr = err;
+		free_extent_state(cached_state);
+		cached_state = NULL;
 		cond_resched();
 		start = end + 1;
 	}
@@ -919,17 +990,17 @@ static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
 	return 0;
 }
 
-int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
+static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root)
 {
-	if (!trans || !trans->transaction) {
-		struct inode *btree_inode;
-		btree_inode = root->fs_info->btree_inode;
-		return filemap_write_and_wait(btree_inode->i_mapping);
-	}
-	return btrfs_write_and_wait_marked_extents(root,
+	int ret;
+
+	ret = btrfs_write_and_wait_marked_extents(root,
 					   &trans->transaction->dirty_pages,
 					   EXTENT_DIRTY);
+	clear_btree_io_tree(&trans->transaction->dirty_pages);
+
+	return ret;
 }
 
 /*
@@ -1652,6 +1723,28 @@ static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
 		btrfs_wait_ordered_roots(fs_info, -1);
 }
 
+static inline void
+btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans,
+			   struct btrfs_fs_info *fs_info)
+{
+	struct btrfs_ordered_extent *ordered;
+
+	spin_lock(&fs_info->trans_lock);
+	while (!list_empty(&cur_trans->pending_ordered)) {
+		ordered = list_first_entry(&cur_trans->pending_ordered,
+					   struct btrfs_ordered_extent,
+					   trans_list);
+		list_del_init(&ordered->trans_list);
+		spin_unlock(&fs_info->trans_lock);
+
+		wait_event(ordered->wait, test_bit(BTRFS_ORDERED_COMPLETE,
+						   &ordered->flags));
+		btrfs_put_ordered_extent(ordered);
+		spin_lock(&fs_info->trans_lock);
+	}
+	spin_unlock(&fs_info->trans_lock);
+}
+
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root)
 {
@@ -1702,6 +1795,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 	}
 
 	spin_lock(&root->fs_info->trans_lock);
+	list_splice(&trans->ordered, &cur_trans->pending_ordered);
 	if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
 		spin_unlock(&root->fs_info->trans_lock);
 		atomic_inc(&cur_trans->use_count);
@@ -1754,6 +1848,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
 	btrfs_wait_delalloc_flush(root->fs_info);
 
+	btrfs_wait_pending_ordered(cur_trans, root->fs_info);
+
 	btrfs_scrub_pause(root);
 	/*
 	 * Ok now we need to make sure to block out any other joins while we
@@ -1842,13 +1938,10 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 	}
 
 	/*
-	 * Since the transaction is done, we should set the inode map cache flag
-	 * before any other comming transaction.
+	 * Since the transaction is done, we can apply the pending changes
+	 * before the next transaction.
 	 */
-	if (btrfs_test_opt(root, CHANGE_INODE_CACHE))
-		btrfs_set_opt(root->fs_info->mount_opt, INODE_MAP_CACHE);
-	else
-		btrfs_clear_opt(root->fs_info->mount_opt, INODE_MAP_CACHE);
+	btrfs_apply_pending_changes(root->fs_info);
 
 	/* commit_fs_roots gets rid of all the tree log roots, it is now
 	 * safe to free the root of tree log roots
@@ -2019,3 +2112,32 @@ int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
 
 	return (ret < 0) ? 0 : 1;
 }
+
+void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
+{
+	unsigned long prev;
+	unsigned long bit;
+
+	prev = cmpxchg(&fs_info->pending_changes, 0, 0);
+	if (!prev)
+		return;
+
+	bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
+	if (prev & bit)
+		btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
+	prev &= ~bit;
+
+	bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
+	if (prev & bit)
+		btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
+	prev &= ~bit;
+
+	bit = 1 << BTRFS_PENDING_COMMIT;
+	if (prev & bit)
+		btrfs_debug(fs_info, "pending commit done");
+	prev &= ~bit;
+
+	if (prev)
+		btrfs_warn(fs_info,
+			"unknown pending changes left 0x%lx, ignoring", prev);
+}