| From 96c2e067ed3e3e004580a643c76f58729206b829 Mon Sep 17 00:00:00 2001 |
| From: Anand Jain <anand.jain@oracle.com> |
| Date: Wed, 30 Sep 2020 21:09:52 +0800 |
| Subject: btrfs: skip devices without magic signature when mounting |
| |
| From: Anand Jain <anand.jain@oracle.com> |
| |
| commit 96c2e067ed3e3e004580a643c76f58729206b829 upstream. |
| |
| Many things can happen after the device is scanned and before the device |
| is mounted. One such thing is losing the BTRFS_MAGIC on the device. |
| If it happens we still won't free that device from the memory and cause |
| the userland confusion. |
| |
| For example: As the BTRFS_IOC_DEV_INFO still carries the device path |
| which does not have the BTRFS_MAGIC, 'btrfs fi show' still lists |
| device which does not belong to the filesystem anymore: |
| |
| $ mkfs.btrfs -fq -draid1 -mraid1 /dev/sda /dev/sdb |
| $ wipefs -a /dev/sdb |
| # /dev/sdb does not contain magic signature |
| $ mount -o degraded /dev/sda /btrfs |
| $ btrfs fi show -m |
| Label: none uuid: 470ec6fb-646b-4464-b3cb-df1b26c527bd |
| Total devices 2 FS bytes used 128.00KiB |
| devid 1 size 3.00GiB used 571.19MiB path /dev/sda |
| devid 2 size 3.00GiB used 571.19MiB path /dev/sdb |
| |
| We need to distinguish the missing signature and invalid superblock, so |
| add a specific error code ENODATA for that. This also fixes failure of |
| fstest btrfs/198. |
| |
| CC: stable@vger.kernel.org # 4.19+ |
| Reviewed-by: Josef Bacik <josef@toxicpanda.com> |
| Signed-off-by: Anand Jain <anand.jain@oracle.com> |
| Reviewed-by: David Sterba <dsterba@suse.com> |
| Signed-off-by: David Sterba <dsterba@suse.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/btrfs/disk-io.c | 8 ++++++-- |
| fs/btrfs/volumes.c | 18 ++++++++++++------ |
| 2 files changed, 18 insertions(+), 8 deletions(-) |
| |
| --- a/fs/btrfs/disk-io.c |
| +++ b/fs/btrfs/disk-io.c |
| @@ -3482,8 +3482,12 @@ struct btrfs_super_block *btrfs_read_dev |
| return ERR_CAST(page); |
| |
| super = page_address(page); |
| - if (btrfs_super_bytenr(super) != bytenr || |
| - btrfs_super_magic(super) != BTRFS_MAGIC) { |
| + if (btrfs_super_magic(super) != BTRFS_MAGIC) { |
| + btrfs_release_disk_super(super); |
| + return ERR_PTR(-ENODATA); |
| + } |
| + |
| + if (btrfs_super_bytenr(super) != bytenr) { |
| btrfs_release_disk_super(super); |
| return ERR_PTR(-EINVAL); |
| } |
| --- a/fs/btrfs/volumes.c |
| +++ b/fs/btrfs/volumes.c |
| @@ -1200,17 +1200,23 @@ static int open_fs_devices(struct btrfs_ |
| { |
| struct btrfs_device *device; |
| struct btrfs_device *latest_dev = NULL; |
| + struct btrfs_device *tmp_device; |
| |
| flags |= FMODE_EXCL; |
| |
| - list_for_each_entry(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; |
| + list_for_each_entry_safe(device, tmp_device, &fs_devices->devices, |
| + dev_list) { |
| + int ret; |
| |
| - if (!latest_dev || |
| - device->generation > latest_dev->generation) |
| + ret = btrfs_open_one_device(fs_devices, device, flags, holder); |
| + if (ret == 0 && |
| + (!latest_dev || device->generation > latest_dev->generation)) { |
| latest_dev = device; |
| + } else if (ret == -ENODATA) { |
| + fs_devices->num_devices--; |
| + list_del(&device->dev_list); |
| + btrfs_free_device(device); |
| + } |
| } |
| if (fs_devices->open_devices == 0) |
| return -EINVAL; |