On Fri, 29 Jul 2016 17:03:43 -0400, Josef Bacik wrote: > On 07/29/2016 03:14 PM, Omar Sandoval wrote: >> On Fri, Jul 29, 2016 at 12:11:53PM -0700, Omar Sandoval wrote: >>> On Fri, Jul 29, 2016 at 08:40:26PM +0200, Stefan Priebe - Profihost AG >>> wrote: >>>> Dear list, >>>> >>>> i'm seeing btrfs no space messages frequently on big filesystems (> 30TB). >>>> >>>> In all cases i'm getting a trace like this one a space_info warning. >>>> (since commit [1]). Could someone please be so kind and help me >>>> debugging / fixing this bug? I'm using space_cache=v2 on all those systems. >>> >>> Hm, so I think this indicates a bug in space accounting somewhere else >>> rather than the free space tree itself. I haven't debugged one of these >>> issues before, I'll see if I can reproduce it. Cc'ing Josef, too. >> >> I should've asked, what sort of filesystem activity triggers this? >> > > Chris just fixed this I think, try his next branch from his git tree > > git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs.git > > and see if it still happens. Thanks, > > Josef
Hi Josef, can you say which patch you have in mind? The tree in question doesn't have any of Chandra's pagesize/sectorsize patches (carefully patched around, for stability and LTS patchability) so I hope it's not the recent commit 8b8b08cb "fix delalloc accounting after copy_from_user faults" because that would be too fiddly (at least for me) to backport correctly. The only other patch I just found missing and which looks like it could/should (I think?) work on top of the 4.4.x pagesize-based calculations in file.c is: a2af23b7 "__btrfs_buffered_write: Pass valid file offset when releasing delalloc space" Would that make sense? Neither I nor any other users of that tree have observed weird space-info underflows so far (and I use my fs daily), so it's definitely something peculiar Stefan is doing with his weird compressed rsync-inplace workload. Odd sector offsets causing slowly creeping space_info underflow sounds to me like it just might be the problem. thanks, Holger -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
