1 files changed, 18 insertions, 12 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6824cb1bd1bb..86bf43d6dfcd 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1976,21 +1976,27 @@ static int ext4_writepage(struct page *page,
                 len = PAGE_CACHE_SIZE;
 
         page_bufs = page_buffers(page);
+        /*
+         * We cannot do block allocation or other extent handling in this
+         * function. If there are buffers needing that, we have to redirty
+         * the page. But we may reach here when we do a journal commit via
+         * journal_submit_inode_data_buffers() and in that case we must write
+         * allocated buffers to achieve data=ordered mode guarantees.
+         */
         if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
                                    ext4_bh_delay_or_unwritten)) {
-                /*
-                 * We don't want to do block allocation, so redirty
-                 * the page and return.  We may reach here when we do
-                 * a journal commit via journal_submit_inode_data_buffers.
-                 * We can also reach here via shrink_page_list but it
-                 * should never be for direct reclaim so warn if that
-                 * happens
-                 */
-                WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
-                                                                PF_MEMALLOC);
                 redirty_page_for_writepage(wbc, page);
-                unlock_page(page);
-                return 0;
+                if (current->flags & PF_MEMALLOC) {
+                        /*
+                         * For memory cleaning there's no point in writing only
+                         * some buffers. So just bail out. Warn if we came here
+                         * from direct reclaim.
+                         */
+                        WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
+                                                        == PF_MEMALLOC);
+                        unlock_page(page);
+                        return 0;
+                }
         }
 
         if (PageChecked(page) && ext4_should_journal_data(inode))