From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:35597 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751655AbaANLxu (ORCPT ); Tue, 14 Jan 2014 06:53:50 -0500 Message-ID: <52D5250A.204@cn.fujitsu.com> Date: Tue, 14 Jan 2014 19:52:42 +0800 From: Wang Shilong MIME-Version: 1.0 To: dsterba@suse.cz, Wang Shilong , linux-btrfs@vger.kernel.org Subject: Re: [PATCH v2 1/4] Btrfs: fix wrong send_in_progress accounting References: <1389086721-19624-1-git-send-email-wangsl.fnst@cn.fujitsu.com> <20140108121609.GF6498@suse.cz> <20140113184024.GT6498@twin.jikos.cz> In-Reply-To: <20140113184024.GT6498@twin.jikos.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 01/14/2014 02:40 AM, David Sterba wrote: > On Wed, Jan 08, 2014 at 11:09:02PM +0800, Wang Shilong wrote: >> Hello David, >> >>> On Tue, Jan 07, 2014 at 05:25:18PM +0800, Wang Shilong wrote: >>>> Steps to reproduce: >>>> # mkfs.btrfs -f /dev/sda8 >>>> # mount /dev/sda8 /mnt >>>> # btrfs sub snapshot -r /mnt /mnt/snap1 >>>> # btrfs sub snapshot -r /mnt /mnt/snap2 >>>> # btrfs send /mnt/snap1 -p /mnt/snap2 -f /mnt/1 >>>> # dmesg >>>> >>>> The problem is that we will sort clone roots(include @send_root), it >>>> might push @send_root before thus @send_root's @send_in_progress will >>>> be decreased twice. >>> Of course, the sort(). I think your fix adds some complexity that's not >>> necessary. Whether the clone_roots array is sorted is not important, we >>> just have to process each root once. >>> >>> send_root becomes a clone_root member, so the missing part is to account >>> in the rollback counter: >>> >>> --- a/fs/btrfs/send.c >>> +++ b/fs/btrfs/send.c >>> @@ -4937,6 +4937,7 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user *arg_) >>> * for possible clone sources. >>> */ >>> sctx->clone_roots[sctx->clone_roots_cnt++].root = sctx->send_root; >>> + clone_sources_to_rollback++; >> Not really, If we fail to come here, we still need decrease @send_root. > Right. I was thinking if the code can be simplified somehow, but don't > have anything vastly better. Can you please add a comment to the first > branch that send_root is processed in the loop and not missed? It looks > unabalanced when it's handled just a few lines below and not in the 1st > loop. Reasonable, i will send v3 for this patch and add some comments. David, really thanks for you costing time to review and correct me.^_^ Thanks, Wang > > thanks, > david > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >