> > 在 2017年12月19日，上午12:02，Vivek Goyal <vgoyal@xxxxxxxxxx> 写道： > > On Mon, Dec 18, 2017 at 08:55:48PM +0800, Chengguang Xu wrote: >> Inspired by encountering unexpected write error when >> upperdir and workdir having different project ids. > > Can you please make this problem descrition little better. By > these two lines I really don't understand what's the problem > you are trying to solve. All I understood was that upperdir > and workdir had different project id. But not sure what > problem it led to and why. > > In fact your first patch changelong was little better. It > atleast said that you encounter "-EXDEV". So is it rename > which fails. So rename is not allowed between two directories > having different project ids? > The background is I encountered an unexpected write error with error code -EXDEV in my environment which didn’t break any rules in overlayfs kernel document. So I did some investigations and found when upperdir and workdir having different project quotas then rename/link operations between those directories would be fail with -EXDEV because project quota asks files in it strictly inherit project id with it’s own. This will make write fail during copy-up process. I wrote first patch to check this condition, but that check seems not sufficient to detect write error, so after discussion with Amir, we decided to check link ability between upperdir and workdir, it is what copy-up actually doing when modifying files in lowerdirs, and also I decided to only print a warning message instead of directly mounting on read-only mode in case there is a special use case just read and do not modify anything in lowerdirs. Thanks, Chengguang. -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
