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Fri, 4 Oct 2019 04:18:08 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 59F66AE6D; Fri, 4 Oct 2019 08:18:05 +0000 (UTC) Subject: Re: [PATCH 2/4] btrfs: delete identified alien device in open_fs_devices To: Anand Jain , linux-btrfs@vger.kernel.org References: <1570175403-4073-1-git-send-email-anand.jain@oracle.com> <1570175403-4073-3-git-send-email-anand.jain@oracle.com> From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: <66defad6-6757-76d2-8819-fd22b9cd1b9e@suse.com> Date: Fri, 4 Oct 2019 11:18:04 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <1570175403-4073-3-git-send-email-anand.jain@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 4.10.19 г. 10:50 ч., Anand Jain wrote: > In open_fs_devices() we identify alien device but we don't reset its > the device::name. So progs device list does not show the device missing > as shown in the script below. > > mkfs.btrfs -fq /dev/sdd && mount /dev/sdd /btrfs > mkfs.btrfs -fq -draid1 -mraid1 /dev/sdc /dev/sdb > sleep 3 # avoid racing with udev's useless scans if needed > btrfs dev add -f /dev/sdb /btrfs > mount -o degraded /dev/sdc /btrfs1 > > No missing device: > btrfs fi show -m /btrfs1 > Label: none uuid: 3eb7cd50-4594-458f-9d68-c243cc49954d > Total devices 2 FS bytes used 128.00KiB > devid 1 size 12.00GiB used 1.26GiB path /dev/sdc > devid 2 size 12.00GiB used 1.26GiB path /dev/sdb > > Signed-off-by: Anand Jain > --- > PS: Fundamentally its wrong approach that btrfs-progs deduces the device > missing state in the userland instead of obtaining it from the kernel. > I objected on the patch, but still those patches got merged, this bug is > one of its side effects. Ironically I wrote patches to read device_state > from the kernel using ioctl, procfs and sysfs but didn't get the due > attention till a merger. > > fs/btrfs/volumes.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c > index 06ec3577c6b4..05ade8c7342b 100644 > --- a/fs/btrfs/volumes.c > +++ b/fs/btrfs/volumes.c > @@ -803,10 +803,10 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, > disk_super = (struct btrfs_super_block *)bh->b_data; > devid = btrfs_stack_device_id(&disk_super->dev_item); > if (devid != device->devid) > - goto error_brelse; > + goto free_alien; > > if (memcmp(device->uuid, disk_super->dev_item.uuid, BTRFS_UUID_SIZE)) > - goto error_brelse; > + goto free_alien; > Imo a better approach is to return a particular error code and do the deletion in open_fs_devices. Otherwise it's not apparent why you use list_for_each_entry_safe in one function to delete something in a different one (whose name by the way doesn't suggest a deletion is going on). Looking at the error I think enodev/enxio is appropriate. > device->generation = btrfs_super_generation(disk_super); > > @@ -845,6 +845,11 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, > > return 0; > > +free_alien: > + fs_devices->num_devices--; > + list_del(&device->dev_list); > + btrfs_free_device(device); > + > error_brelse: > brelse(bh); > blkdev_put(bdev, flags); > @@ -1329,11 +1334,13 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices, > fmode_t flags, void *holder) > { > struct btrfs_device *device; > + struct btrfs_device *tmp_device; > struct btrfs_device *latest_dev = NULL; > > flags |= FMODE_EXCL; > > - list_for_each_entry(device, &fs_devices->devices, dev_list) { > + list_for_each_entry_safe(device, tmp_device, &fs_devices->devices, > + dev_list) { > /* Just open everything we can; ignore failures here */ > if (btrfs_open_one_device(fs_devices, device, flags, holder)) > continue; >