From: Zhiqiang Liu <liuzhiqiang26@huawei.com>
To: "Ewan D. Milne" <emilne@redhat.com>,
lixiaokeng <lixiaokeng@huawei.com>,
Mike Snitzer <snitzer@redhat.com>,
Christoph Hellwig <hch@infradead.org>
Cc: <agk@redhat.com>, <dm-devel@redhat.com>,
"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
<linux-kernel@vger.kernel.org>, <linux-scsi@vger.kernel.org>,
linfeilong <linfeilong@huawei.com>,
"wubo (T)" <wubo40@huawei.com>
Subject: Re: md/dm-mpath: check whether all pgpaths have same uuid in multipath_ctr()
Date: Thu, 25 Mar 2021 09:12:14 +0800 [thread overview]
Message-ID: <4d0860a6-9f53-2e51-91ea-e2b7c4322d9c@huawei.com> (raw)
In-Reply-To: <5612cd9e298488ea9277f8d99ce0fd35240bdc53.camel@redhat.com>
On 2021/3/24 1:11, Ewan D. Milne wrote:
> On Tue, 2021-03-23 at 15:47 +0800, lixiaokeng wrote:
>>
>> On 2021/3/22 22:22, Mike Snitzer wrote:
>>> On Mon, Mar 22 2021 at 4:11am -0400,
>>> Christoph Hellwig <hch@infradead.org> wrote:
>>>
>>>> On Sat, Mar 20, 2021 at 03:19:23PM +0800, Zhiqiang Liu wrote:
>>>>> From: Zhiqiang Liu <liuzhiqiang26@huawei.com>
>>>>>
>>>>> When we make IO stress test on multipath device, there will
>>>>> be a metadata err because of wrong path. In the test, we
>>>>> concurrent execute 'iscsi device login|logout' and
>>>>> 'multipath -r' command with IO stress on multipath device.
>>>>> In some case, systemd-udevd may have not time to process
>>>>> uevents of iscsi device logout|login, and then 'multipath -r'
>>>>> command triggers multipathd daemon calls ioctl to load table
>>>>> with incorrect old device info from systemd-udevd.
>>>>> Then, one iscsi path may be incorrectly attached to another
>>>>> multipath which has different uuid. Finally, the metadata err
>>>>> occurs when umounting filesystem to down write metadata on
>>>>> the iscsi device which is actually not owned by the multipath
>>>>> device.
>>>>>
>>>>> So we need to check whether all pgpaths of one multipath have
>>>>> the same uuid, if not, we should throw a error.
>>>>>
>>>>> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
>>>>> Signed-off-by: lixiaokeng <lixiaokeng@huawei.com>
>>>>> Signed-off-by: linfeilong <linfeilong@huawei.com>
>>>>> Signed-off-by: Wubo <wubo40@huawei.com>
>>>>> ---
>>>>> drivers/md/dm-mpath.c | 52
>>>>> +++++++++++++++++++++++++++++++++++++++++
>>>>> drivers/scsi/scsi_lib.c | 1 +
>>>>> 2 files changed, 53 insertions(+)
>>>>>
>>>>> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
>>>>> index bced42f082b0..f0b995784b53 100644
>>>>> --- a/drivers/md/dm-mpath.c
>>>>> +++ b/drivers/md/dm-mpath.c
>>>>> @@ -24,6 +24,7 @@
>>>>> #include <linux/workqueue.h>
>>>>> #include <linux/delay.h>
>>>>> #include <scsi/scsi_dh.h>
>>>>> +#include <linux/dm-ioctl.h>
>>>>> #include <linux/atomic.h>
>>>>> #include <linux/blk-mq.h>
>>>>>
>>>>> @@ -1169,6 +1170,45 @@ static int parse_features(struct
>>>>> dm_arg_set *as, struct multipath *m)
>>>>> return r;
>>>>> }
>>>>>
>>>>> +#define SCSI_VPD_LUN_ID_PREFIX_LEN 4
>>>>> +#define MPATH_UUID_PREFIX_LEN 7
>>>>> +static int check_pg_uuid(struct priority_group *pg, char
>>>>> *md_uuid)
>>>>> +{
>>>>> + char pgpath_uuid[DM_UUID_LEN] = {0};
>>>>> + struct request_queue *q;
>>>>> + struct pgpath *pgpath;
>>>>> + struct scsi_device *sdev;
>>>>> + ssize_t count;
>>>>> + int r = 0;
>>>>> +
>>>>> + list_for_each_entry(pgpath, &pg->pgpaths, list) {
>>>>> + q = bdev_get_queue(pgpath->path.dev->bdev);
>>>>> + sdev = scsi_device_from_queue(q);
>>>>
>>>> Common dm-multipath code should never poke into scsi
>>>> internals. This
>>>> is something for the device handler to check. It probably also
>>>> won't
>>>> work for all older devices.
>>>
>>> Definitely.
>>>
>>> But that aside, userspace (multipathd) _should_ be able to do extra
>>> validation, _before_ pushing down a new table to the kernel, rather
>>> than
>>> forcing the kernel to do it.
>>>
>>
>> Martin (committer of multipath-tools) said that:
>> "Don't get me wrong, I don't argue against tough testing. But we
>> should
>> be aware that there are always time intervals during which
>> multipathd's
>> picture of the present devices is different from what the kernel
>> sees."
>>
>> It is difficult to solve this in multipathd.
>>
>> Regards,
>> Lixiaokeng
>>
>
> I think the patch is no good. There are plenty of devices that don't
> support VPD page 83h:
>
> int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
> {
> u8 cur_id_type = 0xff;
> u8 cur_id_size = 0;
> unsigned char *d, *cur_id_str;
> unsigned char __rcu *vpd_pg83;
> int id_size = -EINVAL;
>
> rcu_read_lock();
> vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
> if (!vpd_pg83) {
> rcu_read_unlock();
> return -ENXIO;
> }
>
> and the DM layer should not be looking at the properties of the
> underlying devices in this way anyway. It should be pushed down
> to the table.
>
Thanks for your suggestion.
I will have a try to modify the patch as your advice.
Regards
Zhiqiang Liu.
> -Ewan
>
>
>
>
> .
>
next prev parent reply other threads:[~2021-03-25 1:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-20 7:19 [PATCH] md/dm-mpath: check whether all pgpaths have same uuid in multipath_ctr() Zhiqiang Liu
2021-03-20 14:34 ` kernel test robot
2021-03-22 8:11 ` Christoph Hellwig
2021-03-22 14:22 ` Mike Snitzer
2021-03-23 7:47 ` lixiaokeng
2021-03-23 17:11 ` Ewan D. Milne
2021-03-25 1:12 ` Zhiqiang Liu [this message]
2021-03-25 1:21 ` Zhiqiang Liu
2021-03-25 15:14 ` Mike Snitzer
2021-03-26 17:12 ` [dm-devel] " Martin Wilck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4d0860a6-9f53-2e51-91ea-e2b7c4322d9c@huawei.com \
--to=liuzhiqiang26@huawei.com \
--cc=agk@redhat.com \
--cc=dm-devel@redhat.com \
--cc=emilne@redhat.com \
--cc=hch@infradead.org \
--cc=jejb@linux.ibm.com \
--cc=linfeilong@huawei.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=lixiaokeng@huawei.com \
--cc=martin.petersen@oracle.com \
--cc=snitzer@redhat.com \
--cc=wubo40@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).