On Tue 25-08-20 10:11:29, yebin wrote: > Your patch certainly can fix the problem with my testcases, but I don't > think it's a good way. There are other paths that can call > do_invalidatepage , for instance block ioctl to discard and zero_range. OK, good point! So my patch is a cleanup that stands on its own and we should do it regardless. But I agree we need more to completely fix this. I don't quite like the callback you've added just for this special case (furthermore it grows size of every buffer_head and there can be lots of those). But I agree with the general idea that we shouldn't discard buffers that the filesystem is working with. In fact I believe that fallocate(2) and zeroout/discard ioctls should return EBUSY if they are run against a mounted device because with 99% probability something went wrong and you're accidentally discarding the wrong device. But maybe I'm wrong. I'll run this idea through other fs developers. Honza > On 2020/8/24 23:51, Jan Kara wrote: > > On Sat 22-08-20 16:22:16, Ye Bin wrote: > > > Ye Bin (2): > > > ext4: Add comment to BUFFER_FLAGS_DISCARD for search code > > > jbd2: Fix race between do_invalidatepage and init_page_buffers > > > > > > fs/buffer.c | 12 +++++++++++- > > > fs/jbd2/journal.c | 7 +++++++ > > > include/linux/buffer_head.h | 2 ++ > > > 3 files changed, 20 insertions(+), 1 deletion(-) > > Thanks for the good description of the problem and the analysis. I could > > now easily understand what was really happening on your system. I think the > > problem should be fixed differently through - it is a problem of > > block_write_full_page() that it invalidates buffers while JBD2 is working > > with them. Attached patch should also fix the problem. Can you please test > > whether it fixes your testcase as well? Thanks! > > > > Honza > > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
