From: Qu Wenruo Date: Wed, 21 Oct 2020 06:25:02 +0000 (+0800) Subject: btrfs: assert page mapping lock in attach_extent_buffer_page X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0d01e247a06b9f36f685edf6c2e74f79f60df9cd;p=linux.git btrfs: assert page mapping lock in attach_extent_buffer_page When calling attach_extent_buffer_page(), either we're attaching anonymous pages, called from btrfs_clone_extent_buffer(), or we're attaching btree inode pages, called from alloc_extent_buffer(). For the latter case, we should hold page->mapping->private_lock to avoid parallel changes to page->private. Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 119ced4a501b..092ccb811eac 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3102,6 +3102,15 @@ static int submit_extent_page(unsigned int opf, static void attach_extent_buffer_page(struct extent_buffer *eb, struct page *page) { + /* + * If the page is mapped to btree inode, we should hold the private + * lock to prevent race. + * For cloned or dummy extent buffers, their pages are not mapped and + * will not race with any other ebs. + */ + if (page->mapping) + lockdep_assert_held(&page->mapping->private_lock); + if (!PagePrivate(page)) attach_page_private(page, eb); else