+ clear_page_dirty_for_io(page);
+ /*
+ * We have to be very careful here! Nothing protects
+ * writeback path against i_size changes and the page
+ * can be writeably mapped into page tables. So an
+ * application can be growing i_size and writing data
+ * through mmap while writeback runs.
+ * clear_page_dirty_for_io() write-protects our page in
+ * page tables and the page cannot get written to again
+ * until we release page lock. So only after
+ * clear_page_dirty_for_io() we are safe to sample
+ * i_size for ext4_bio_write_page() to zero-out tail of
+ * the written page. We rely on the barrier provided by
+ * TestClearPageDirty in clear_page_dirty_for_io() to
+ * make sure i_size is really sampled only after page
+ * tables are updated.
+ */
+ if (size != i_size_read(inode)) {
+ set_page_dirty(page);
+ goto skip_page;
+ }
+