On Tue 26-01-21 10:22:56, Jens Axboe wrote: > On 1/26/21 3:02 AM, Jan Kara wrote: > > On Thu 07-01-21 16:40:34, Jan Kara wrote: > >> blkdev_fallocate() tries to detect whether a discard raced with an > >> overlapping write by calling invalidate_inode_pages2_range(). However > >> this check can give both false negatives (when writing using direct IO > >> or when writeback already writes out the written pagecache range) and > >> false positives (when write is not actually overlapping but ends in the > >> same page when blocksize < pagesize). This actually causes issues for > >> qemu which is getting confused by EBUSY errors. > >> > >> Fix the problem by removing this conflicting write detection since it is > >> inherently racy and thus of little use anyway. > >> > >> Reported-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> > >> CC: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx> > >> Link: https://lore.kernel.org/qemu-devel/20201111153913.41840-1-mlevitsk@xxxxxxxxxx > >> Signed-off-by: Jan Kara <jack@xxxxxxx> > > > > Jens, can you please pick up this patch? Thanks! > > Picked it up for 5.12, hope that works. It looks simple enough but not > really meeting criteria for 5.11 at this point. Sure, 5.12 is fine. We've been living with the current behavior for quite some time and not many people complained... Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
