On Sat, Mar 12, 2016 at 09:47:23AM +0800, Ming Lei wrote: > On Fri, 11 Mar 2016 15:24:33 -0700 > Andrea Righi <righi.andrea@xxxxxxxxx> wrote: > > > On Sat, Mar 05, 2016 at 08:31:03PM -0900, Kent Overstreet wrote: > > > On Fri, Mar 04, 2016 at 10:30:44AM -0700, Andrea Righi wrote: > > > > On Sun, Feb 28, 2016 at 08:46:16PM -0700, Andrea Righi wrote: > > > > > On Sun, Feb 28, 2016 at 06:53:33PM -0700, Andrea Righi wrote: > > > > > ... > > > > > > I'm using 4.5.0-rc5+, from Linus' git. I'll try to do a git bisect > > > > > > later, I'm pretty sure this problem has been introduced recently (i.e., > > > > > > I've never seen this issue with 4.1.x). > > > > > > > > > > I confirm, just tested kernel 4.1 and this problem doesn't happen. > > > > > > > > Alright, I had some spare time to bisect this problem and I found that > > > > the commit that introduced this issue is c66a14d. > > > > > > > > So, I tried to revert the commit (with some changes to fix conflicts and > > > > ABI changes) and now multipath seems to work fine for me (no hung task). > > > > > > Is it hanging on first IO, first large IO, or just randomly? > > > > It's always the very first O_DIRECT I/O, in general the task gets stuck > > in do_blockdev_direct_IO(). > > I can reproduce the issue too, and looks it is a MD issue instead of block. > Andrea, could you try the following patch to see if it can fix your issue? > > --- > From 43fc9c221e53c64f2df7c100c77cc25c4a98c607 Mon Sep 17 00:00:00 2001 > From: Ming Lei <ming.lei@xxxxxxxxxxxxx> > Date: Sat, 12 Mar 2016 09:29:40 +0800 > Subject: [PATCH] md: multipath: don't hardcopy bio in .make_request path > > Inside multipath_make_request(), multipath maps the incoming > bio into low level device's bio, but it is totally wrong to > copy the bio into mapped bio via '*mapped_bio = *bio'. For > example, .__bi_remaining is kept in the copy, especially if > the incoming bio is chained to via bio splitting, so .bi_end_io > can't be called for the mapped bio at all in the completing path > in this kind of situation. > > This patch fixes the issue by using clone style. Applied, thanks! Looks this issue exists since immutable bio is introduced, but triggered recently. Will add to stable too. Thanks, Shaohua -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
