From: Eric Sandeen <sandeen@sandeen.net>
To: Eric Sandeen <sandeen@redhat.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>, Jes.Sorensen@redhat.com
Subject: Re: [PATCH] block: return EBUSY from drop_partitions on mounted whole disk device
Date: Wed, 2 Mar 2016 16:13:09 -0600 [thread overview]
Message-ID: <56D76575.6050901@sandeen.net> (raw)
In-Reply-To: <56D5FF69.6070004@redhat.com>
On 3/1/16 2:45 PM, Eric Sandeen wrote:
> On 8/5/15 2:13 PM, Eric Sandeen wrote:
>> The BLKRRPART ioctl already fails today if any partition under
>> the device is mounted. However, if we mkfs a whole disk and mount
>> it, BLKRRPART happily proceeds down the invalidation path, which
>> seems like a bad idea.
>>
>> Check whether the whole device is mounted by checking bd_super,
>> and return -EBUSY if so.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> I don't know for sure if this is the right approach, but figure
>> I'll ask in the form of a patch. ;)
>
> I'm now thinking that this is not the right approach. :( I got a
> bug report stating that during some md raid1 testing with replacing
> failed disks, filesystems were losing data. I haven't reproduced
> that part yet, but...
>
> It's hitting the "bd_super" case added in the patch below, and returning
> -EBUSY to md when mdadm tries to to remove a disk:
>
> # mdadm /dev/md0 -r /dev/loop0
> mdadm: hot remove failed for /dev/loop0: Device or resource busy
FWIW, just ignore me, I was being an idiot. a) the patch *prevents*
the corruption; does not cause it; without the EBUSY, drop_partitions
will get to invalidate_inodes() etc, and no wonder data is lost.
And b) the above EBUSY is because I forgot to fail the disk first. :/
Nothing to see here, move along, sorry!
-Eric
next prev parent reply other threads:[~2016-03-02 22:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-05 19:13 [PATCH] block: return EBUSY from drop_partitions on mounted whole disk device Eric Sandeen
2016-03-01 20:45 ` Eric Sandeen
2016-03-02 3:38 ` Eric Sandeen
2016-03-02 22:13 ` Eric Sandeen [this message]
2016-03-02 22:15 ` Jens Axboe
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