From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josef Bacik Subject: Re: btrfs lock-up on copying files Date: Thu, 30 Jun 2011 10:52:57 -0400 Message-ID: <4E0C8DC9.6080402@redhat.com> References: <20110630123738.6042e563@natsu> <4E0C8A3F.2060202@redhat.com> <20110630204347.0d70506e@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: linux-btrfs To: Roman Mamedov Return-path: In-Reply-To: <20110630204347.0d70506e@natsu> List-ID: On 06/30/2011 10:43 AM, Roman Mamedov wrote: > On Thu, 30 Jun 2011 10:37:51 -0400 > Josef Bacik wrote: > >> Can you do sysrq+w when this happens? The caching kthread should still >> be able to make progress, which is what we seem to be waiting on. Does >> it eventually unhang and continue on? Thanks, > > Hello, > > Unfortunately I already rebooted that server so can't check SysRq+W. > Before the reboot I waited for about 40 minutes, and the block device seemed to be 100% idle during all this time. > I got an advice on IRC to wait for a couple of hours if this happens again, which I am going to try if it does. > Oh well crud I see what happened, the caching_kthread didn't even get started, kthreadd got locked up waiting on the page lock for migration. I will try and figure out what to do for this. Thanks for reporting it, Josef