From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Bacik Subject: Re: btrfs hang in flush-btrfs-5 Date: Wed, 13 Jul 2011 10:55:06 -0400 Message-ID: <4E1DB1CA.1050307@redhat.com> References: <4E1B08FC.6030907@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: linux-btrfs@vger.kernel.org To: Jeremy Sanders Return-path: In-Reply-To: List-ID: On 07/11/2011 05:21 PM, Jeremy Sanders wrote: > Josef Bacik wrote: > >> On 07/11/2011 07:40 AM, Jeremy Sanders wrote: >>> Jeremy Sanders wrote: >>> >>>> Hi - I'm trying btrfs with kernel 2.6.38.8-32.fc15.x86_64 (a Fedora >>>> kernel). I'm just doing a tar-to-tar copy onto the file system with >>>> compress- force=zlib. Here are some traces of the stuck processes. >>> >>> I've managed to reproduce the hang using the latest btrfs from the >>> repository. I had to remove some of the tracing lines to get it to >>> compile under 2.6.38.8 and an ioctl which wasn't defined. Here is is >>> where it is stuck: >>> >> >> Hrm well that is just unlikely and hard to hit. Will you try this and >> see if it helps you? Thanks, > > It's got quite a bit further past than where it got before and hasn't > crashed yet. I will let you know when it has finished ok. > > I see that the btrfs-delalloc (rather than endio-write) thread is taking up > 100% of CPU and the write speed seems to have dropped during the copying, > however. The copy started with using endio-write fully on both cores and now > is using dealloc a lot. > When you see that can you get sysrq+w or sysrq+t to get a stacktrace of what it's doing so I can see if it's something that can be fixed. Thanks, Josef