On Wed 11-01-17 18:35:02, Steve Kenton wrote: > I first noticed this with 4.10rc2+ while testing some changes I was > making to the UDF driver but it's neither a new problem nor related to my > changes. Below is a test run on a stock Ubuntu 14.04 system with kernel > 3.19 and the results are the same. If I copy large video files to the DVD > I can put 4+GiB on the disk, it syncs as expected and life is good. If I > try to copy Linus' 2.7GiB repo to the DVD it is still going after running > overnight and after killing the copy sync does not return for hours, > which hangs a graceful reboot. I should note that while the sync has not > completed the filesystem on the DVD seems usable for the light testing I > did using df, ls, find etc and the verbose copy was still proceeding if > slowly when I killed it. Yeah, I think the problem is that seeking just kills the DVD drive and UDF driver in Linux is not very good in avoiding them. So writing to a UDF filesystem on DVD media directly simply does not work very well. Also if you copy a directory tree, there are lots of inplace updates of directories happening so that may contribute to slowness as well. So all in all I don't think this was ever something we were trying to make work reasonably since people don't tend to use DVD like this... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
