On Thu, Jan 27, 2022 at 10:47:37AM +0100, Jan Kara wrote: > On Wed 26-01-22 16:50:35, Christoph Hellwig wrote: > > Nothing prevents a file system or userspace opener of the block device > > from redirtying the page right afte sync_blockdev returned. Fortunately > > data in the page cache during a block device change is mostly harmless > > anyway. > > > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > > My understanding was these warnings are there to tell userspace it is doing > something wrong. Something like the warning we issue when DIO races with > buffered IO... I'm not sure how useful they are but I don't see strong > reason to remove them either... Well, it is not just a warning, but also fails the command. With some of the reduced synchronization blktests loop/002 can hit them pretty reliably.
