From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mondschein.lichtvoll.de ([194.150.191.11]:51492 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751113AbaGYJyj convert rfc822-to-8bit (ORCPT ); Fri, 25 Jul 2014 05:54:39 -0400 From: Martin Steigerwald To: Liu Bo , linux-btrfs@vger.kernel.org Subject: Re: [PATCH] Btrfs: fix compressed write corruption on enospc Date: Fri, 25 Jul 2014 11:54:37 +0200 Message-ID: <1537782.AGn1dfcASJ@merkaba> In-Reply-To: <1406213285-19607-1-git-send-email-bo.li.liu@oracle.com> References: <1406213285-19607-1-git-send-email-bo.li.liu@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am Donnerstag, 24. Juli 2014, 22:48:05 schrieben Sie: > When failing to allocate space for the whole compressed extent, we'll > fallback to uncompressed IO, but we've forgotten to redirty the pages > which belong to this compressed extent, and these 'clean' pages will > simply skip 'submit' part and go to endio directly, at last we got data > corruption as we write nothing. > > Signed-off-by: Liu Bo > --- > fs/btrfs/inode.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 3668048..8ea7610 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -709,6 +709,18 @@ retry: > unlock_extent(io_tree, async_extent->start, > async_extent->start + > async_extent->ram_size - 1); > + > + /* > + * we need to redirty the pages if we decide to > + * fallback to uncompressed IO, otherwise we > + * will not submit these pages down to lower > + * layers. > + */ > + extent_range_redirty_for_io(inode, > + async_extent->start, > + async_extent->start + > + async_extent->ram_size - 1); > + > goto retry; > } > goto out_free; I am testing this currently. So far no lockup. Lets see. Still has not filled the the block device with trees completely after I balanced them: Label: 'home' uuid: […] Total devices 2 FS bytes used 125.57GiB devid 1 size 160.00GiB used 153.00GiB path /dev/dm-0 devid 2 size 160.00GiB used 153.00GiB path /dev/mapper/sata-home I believe the lockups happen more easily if the trees occupy all of disk space. Well I will do some compiling of some KDE components which may let BTRFS fill all space again. This patch will mean it when it can´t make enough free space in the (fragmented) tree it will write uncompressed? This would mean that one would have a defragment trees regularily to allow for writes to happen compressed at all times. Well… of course still better than lockup or corruption. Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7