ext4: fix WARN_ON from ext4_releasepage()

ext4_releasepage() warns when it is passed a page with PageChecked set.
However this can correctly happen when invalidate_inode_pages2_range()
invalidates pages - and we should fail the release in that case. Since
the page was dirty anyway, it won't be discarded and no harm has
happened but it's good to be safe. Also remove bogus page_has_buffers()
check - we are guaranteed page has buffers in this function.

Reported-by: Zheng Liu <gnehzuil.liu@gmail.com>
Tested-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4f1d54a88d8cf5d38239500e1f591a44e31f1124..117a9e7aa4a0f2047842e4d3bfac446b02d5dd88 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3018,8 +3018,8 @@ static int ext4_releasepage(struct page *page, gfp_t wait)
 
        trace_ext4_releasepage(page);
 
-       WARN_ON(PageChecked(page));
-       if (!page_has_buffers(page))
+       /* Page has dirty journalled data -> cannot release */
+       if (PageChecked(page))
                return 0;
        if (journal)
                return jbd2_journal_try_to_free_buffers(journal, page, wait);