On Fri, Aug 9, 2024 at 8:57 PM Namjae Jeon <linkinjeon@xxxxxxxxxx> wrote: > > 2024년 8월 8일 (목) 오후 3:40, Dongliang Cui <dongliang.cui@xxxxxxxxxx>님이 작성: > > > > We found that when writing a large file through buffer write, if the > > disk is inaccessible, exFAT does not return an error normally, which > > leads to the writing process not stopping properly. > > > > To easily reproduce this issue, you can follow the steps below: > > > > 1. format a device to exFAT and then mount (with a full disk erase) > > 2. dd if=/dev/zero of=/exfat_mount/test.img bs=1M count=8192 > > 3. eject the device > > > > You may find that the dd process does not stop immediately and may > > continue for a long time. > > > > The root cause of this issue is that during buffer write process, > > exFAT does not need to access the disk to look up directory entries > > or the FAT table (whereas FAT would do) every time data is written. > > Instead, exFAT simply marks the buffer as dirty and returns, > > delegating the writeback operation to the writeback process. > > > > If the disk cannot be accessed at this time, the error will only be > > returned to the writeback process, and the original process will not > > receive the error, so it cannot be returned to the user side. > > > > When the disk cannot be accessed normally, an error should be returned > > to stop the writing process. > > > > xfstests results: > > > > Apart from generic/622, all other shutdown-related cases can pass. > > > > generic/622 fails the test after the shutdown ioctl implementation, but > > when it's not implemented, this case will be skipped. > > > > This case designed to test the lazytime mount option, based on the test > > results, it appears that the atime and ctime of files cannot be > > synchronized to the disk through interfaces such as sync or fsync. > > It seems that it has little to do with the implementation of shutdown > > itself. > > > > If you need detailed information about generic/622, I can upload it. > > > > Signed-off-by: Dongliang Cui <dongliang.cui@xxxxxxxxxx> > > Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx> > You still haven't updated the patch subject and description with > shutdown support. > I've directly updated it and applied it to #dev. > Thanks for your patch:) Thank you for your help in updating.
