From 6dcc693bc57f198bd85a7881eb59a915366fae1e Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 1 Dec 2016 11:46:40 -0500 Subject: [PATCH] ext4: warn when page is dirtied without buffers Warn when a page is dirtied without buffers (as that will likely lead to a crash in ext4_writepages()) or when it gets newly dirtied without the page being locked (as there is nothing that prevents buffers to get stripped just before calling set_page_dirty() under memory pressure). Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 861f848..7d95b61 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3714,6 +3714,13 @@ static int ext4_journalled_set_page_dirty(struct page *page) return __set_page_dirty_nobuffers(page); } +static int ext4_set_page_dirty(struct page *page) +{ + WARN_ON_ONCE(!PageLocked(page) && !PageDirty(page)); + WARN_ON_ONCE(!page_has_buffers(page)); + return __set_page_dirty_buffers(page); +} + static const struct address_space_operations ext4_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, @@ -3721,6 +3728,7 @@ static const struct address_space_operations ext4_aops = { .writepages = ext4_writepages, .write_begin = ext4_write_begin, .write_end = ext4_write_end, + .set_page_dirty = ext4_set_page_dirty, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, @@ -3753,6 +3761,7 @@ static const struct address_space_operations ext4_da_aops = { .writepages = ext4_writepages, .write_begin = ext4_da_write_begin, .write_end = ext4_da_write_end, + .set_page_dirty = ext4_set_page_dirty, .bmap = ext4_bmap, .invalidatepage = ext4_da_invalidatepage, .releasepage = ext4_releasepage, -- 2.7.4