From: Filipe Manana fdmanana@suse.com
[ Upstream commit a57c2d4e46f519b24558ae0752c17eec416ac72a ]
When removing a delayed item, or releasing which will remove it as well, we will modify one of the delayed node's rbtrees and item counter if the delayed item is in one of the rbtrees. This require having the delayed node's mutex locked, otherwise we will race with other tasks modifying the rbtrees and the counter.
This is motivated by a previous version of another patch actually calling btrfs_release_delayed_item() after unlocking the delayed node's mutex and against a delayed item that is in a rbtree.
So assert at __btrfs_remove_delayed_item() that the delayed node's mutex is locked.
Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/delayed-inode.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 88db451697b0a..f7fb42833e9db 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -412,6 +412,7 @@ static void finish_one_item(struct btrfs_delayed_root *delayed_root)
static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item) { + struct btrfs_delayed_node *delayed_node = delayed_item->delayed_node; struct rb_root_cached *root; struct btrfs_delayed_root *delayed_root;
@@ -419,18 +420,21 @@ static void __btrfs_remove_delayed_item(struct btrfs_delayed_item *delayed_item) if (RB_EMPTY_NODE(&delayed_item->rb_node)) return;
- delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root; + /* If it's in a rbtree, then we need to have delayed node locked. */ + lockdep_assert_held(&delayed_node->mutex); + + delayed_root = delayed_node->root->fs_info->delayed_root;
BUG_ON(!delayed_root);
if (delayed_item->type == BTRFS_DELAYED_INSERTION_ITEM) - root = &delayed_item->delayed_node->ins_root; + root = &delayed_node->ins_root; else - root = &delayed_item->delayed_node->del_root; + root = &delayed_node->del_root;
rb_erase_cached(&delayed_item->rb_node, root); RB_CLEAR_NODE(&delayed_item->rb_node); - delayed_item->delayed_node->count--; + delayed_node->count--;
finish_one_item(delayed_root); }