From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:47396 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756062AbaGaIpQ (ORCPT ); Thu, 31 Jul 2014 04:45:16 -0400 Message-ID: <53DA0211.4000000@oracle.com> Date: Thu, 31 Jul 2014 16:45:05 +0800 From: Anand Jain MIME-Version: 1.0 To: miaox@cn.fujitsu.com CC: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] btrfs: replace seed device followed by unmount causes kernel WARNING In-Reply-To: <53D8A1DA.2060703@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: References: <1406291614-29544-1-git-send-email-anand.jain@oracle.com> <53D8A1DA.2060703@cn.fujitsu.com> On 30/07/2014 15:42, Miao Xie wrote: > On Fri, 25 Jul 2014 20:33:34 +0800, Anand Jain wrote: >> After the seed device has been replaced the new target device >> is no more a seed device. So we need to bring that state in >> the fs_devices. >> >> reproducer: >> mount /dev/sdb /btrfs >> btrfs dev add /dev/sdc /btrfs >> btrfs rep start -B /dev/sdb /dev/sdd /btrfs >> umount /btrfs >> >> WARNING: CPU: 0 PID: 12661 at fs/btrfs/volumes.c:891 __btrfs_close_devices+0x1b0/0x200 [btrfs]() >> :: >> >> __btrfs_close_devices() >> :: >> WARN_ON(fs_devices->open_devices); >> WARN_ON(fs_devices->rw_devices); >> >> per the btrfs-devlist tool (to dump fs_devices and >> btrfs_device from the kernel) the num_device, open_devices, >> rw_devices are still at 1 but the total_device is at 2, >> even after the seed device has been replaced in the above example. >> >> Signed-off-by: Anand Jain >> --- >> fs/btrfs/dev-replace.c | 13 +++++++++++++ >> 1 file changed, 13 insertions(+) >> >> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c >> index eea26e1..a144bb1 100644 >> --- a/fs/btrfs/dev-replace.c >> +++ b/fs/btrfs/dev-replace.c >> @@ -569,6 +569,19 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, >> >> btrfs_rm_dev_replace_blocked(fs_info); >> >> + /* >> + * if we are replacing a seed device with a writable device >> + * then FS won't be a seeding FS any more. >> + */ >> + if (src_device->fs_devices->seeding && !src_device->writeable) { > > First, why not move this code into btrfs_rm_dev_replace_srcdev()? > > Then if the first condition is true, the second one(!src_device->writeable) must be true > because all the devices in the seed fs_device must be read-only. so only the first > check is enough. > >> + fs_info->fs_devices->rw_devices++; > > If src is missing dev, we would increase it twice. > >> + fs_info->fs_devices->num_devices++; >> + fs_info->fs_devices->open_devices++; >> + >> + fs_info->fs_devices->seeding = 0; >> + fs_info->fs_devices->seed = NULL; > > In fact, we may have several seed fs_devices in one fs, and the seed fs_device > which includes src might not the first one, so assign seed to be NULL would break > the seed fs_device list. Yep I had question when writing this patch but later decided to reset seed and seeding. if I am not wrong don't reset seeding and seed will do as well. Thanks for reviewing. Anand > Thanks > Miao > >> + } >> + >> btrfs_rm_dev_replace_srcdev(fs_info, src_device); >> >> btrfs_rm_dev_replace_unblocked(fs_info); >> > > -- > 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 >