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From: Nikolay Borisov <nborisov@suse.com>
To: Anand Jain <anand.jain@oracle.com>, linux-btrfs@vger.kernel.org
Cc: Johannes.Thumshirn@wdc.com
Subject: Re: [PATCH v2] btrfs: free device without BTRFS_MAGIC
Date: Wed, 23 Sep 2020 14:09:52 +0300	[thread overview]
Message-ID: <a0dc643f-81ee-8450-1371-d5c7f89dd8db@suse.com> (raw)
In-Reply-To: <1ee9b318e3bb851aaec9c1efd1eadb117ad46638.1600741332.git.anand.jain@oracle.com>



On 22.09.20 г. 6:13 ч., Anand Jain wrote:
> 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 causes
> the userland to confuse.
> 
> For example: As the BTRFS_IOC_DEV_INFO still carries the device path which
> does not have the BTRFS_MAGIC, the btrfs fi show still shows device
> which does not belong. As shown below.
> 
> mkfs.btrfs -fq -draid1 -mraid1 /dev/sda /dev/sdb
> 
> wipefs -a /dev/sdb
> mount -o degraded /dev/sda /btrfs
> btrfs fi show -m
> 
> /dev/sdb does not contain BTRFS_MAGIC and we still show it as part of
> btrfs.
> 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
> 
> Fix is to return -ENODATA error code in btrfs_read_dev_one_super()
> when BTRFS_MAGIC check fails, and its parent open_fs_devices() to
> free the device in the mount-thread.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>

Has an fstest for this been submitted ?

<snip>

  reply	other threads:[~2020-09-23 11:09 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-19  2:52 [PATCH] btrfs: free device without BTRFS_MAGIC Anand Jain
2020-09-21  9:44 ` Johannes Thumshirn
2020-09-21 10:52 ` Johannes Thumshirn
2020-09-21 11:19   ` Anand Jain
2020-09-22  3:13 ` [PATCH v2] " Anand Jain
2020-09-23 11:09   ` Nikolay Borisov [this message]
2020-09-24 11:55     ` Anand Jain
2020-09-28 18:14   ` Josef Bacik
2020-09-30  7:21     ` Anand Jain
2020-09-30 12:41       ` Josef Bacik
2020-09-30 13:09 ` [PATCH v3] " Anand Jain
2020-10-01  1:05   ` Anand Jain
2020-10-01 10:49   ` David Sterba

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