From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leho Kraav Subject: Re: btrfs 3.2.2 -> 3.3.1 upgrade finally ate babies, some advice? Date: Mon, 09 Apr 2012 17:44:10 +0300 Message-ID: <4F82F5BA.3080504@kraav.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Cc: Linux BTRFS , Liu Bo To: Daniel J Blueman Return-path: In-Reply-To: List-ID: On 09.04.2012 17:35, Daniel J Blueman wrote: > Leho Kraav kraav.com> writes: > [] >> Apr 8 02:46:11 s9 kernel: [ 189.691778] attempt to access beyond end >> of device >> Apr 8 02:46:11 s9 kernel: [ 189.691787] dm-3: rw=129, want=23361976, >> limit=20967424 > > I recently bumped into this too [1]. Liu Bo posted a patch for it [2], > which tests out fine here. The workaround is to not mount with > 'discard' until eg ~3.4-rc3 or later. > > [1] http://permalink.gmane.org/gmane.comp.file-systems.btrfs/16409 > [2] http://permalink.gmane.org/gmane.comp.file-systems.btrfs/16649 Oh wow, thanks. This sounds exactly like what happened. I got the livelock post off my search results, but the patch post doesn't seem to have any of the keywords I was looking for, since I had no idea it could be related to discards. So can this become a problem earlier too, not only when the space used is approaching limits? If not, I think I should be good until 3.4: $ sudo btrfs fi show Label: 'S9-HOME' uuid: 1ed06dbc-e1b7-433f-8d1b-19cf1f7756f1 Total devices 1 FS bytes used 12.93GB devid 1 size 60.00GB used 20.04GB path /dev/dm-0 Label: 'S9-ROOT' uuid: 6206dfce-afcf-4afe-9047-b1c88a7889fd Total devices 1 FS bytes used 8.75GB devid 1 size 30.00GB used 18.29GB path /dev/dm-1 I think I'd like to keep using "discard" for SSD still, unless a smart person says it's not particularly useful anyway. So while I'm on 3.3, is the patch from gmane:16649 good enough to eliminate immediate dangers? And is the previous filesystem still hosed for good then? Or mounting the images with -discard might help?