Btrfs: add missing end_page_writeback on submit_extent_page failure

If submit_extent_page() fails in write_one_eb(), we end up with the current
page not marked dirty anymore, unlocked and marked for writeback. But we never
end up calling end_page_writeback() against the page, which will make calls to
filemap_fdatawait_range (e.g. at transaction commit time) hang forever waiting
for the writeback bit to be cleared from the page.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/extent_io.c

@@ -3663,6 +3663,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
 		if (ret) {
 			set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
 			SetPageError(p);
+			end_page_writeback(p);
 			if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
 				end_extent_buffer_writeback(eb);
 			ret = -EIO;