From: Yu Kuai <yukuai1@huaweicloud.com>
To: Mateusz Kusiak <mateusz.kusiak@linux.intel.com>,
DM-devel-linux <dm-devel@lists.linux.dev>
Cc: linux-raid@vger.kernel.org, "yukuai (C)" <yukuai3@huawei.com>
Subject: Re: regression: mdadm detects dm-device as partition
Date: Mon, 25 Mar 2024 10:41:47 +0800 [thread overview]
Message-ID: <c7db2443-06d4-a199-02ac-f58204118cb6@huaweicloud.com> (raw)
In-Reply-To: <35e0eae0-7fb0-4029-8445-997e22c21482@linux.intel.com>
Hi,
在 2024/03/21 17:17, Mateusz Kusiak 写道:
> Hello,
> We discovered an issue when trying to create imsm container with mdadm
> on dm-device.
>
> The scenario is as follows:
>
> 1. Create dm device
> # echo -e '0 195312 linear /dev/nvme2n1 0' | dmsetup create nvme2n1DM
>
> 2. Create IMSM container.
> # dmdev=$(readlink -f /dev/mapper/nvme2n1DM)
> # export IMSM_DEVNAME_AS_SERIAL=1 IMSM_NO_PLATFORM=1; mdadm --create
> /dev/md/container --metadata=imsm --raid-disks=1 $dmdev --force
>
> Result:
>
> Error message is displayed
> # mdadm: imsm: /dev/dm-0 is a partition, cannot be used in IMSM
>
> Mdadm's function for checking "if partition" looks like so.
>
> int test_partition(int fd)
> {
> /* Check if fd is a whole-disk or a partition.
> * BLKPG will return EINVAL on a partition, and BLKPG_DEL_PARTITION
> * will return ENXIO on an invalid partition number.
> */
> struct blkpg_ioctl_arg a;
> struct blkpg_partition p;
> a.op = BLKPG_DEL_PARTITION;
> a.data = (void*)&p;
> a.datalen = sizeof(p);
> a.flags = 0;
> memset(a.data, 0, a.datalen);
> p.pno = 1<<30;
> if (ioctl(fd, BLKPG, &a) == 0)
> /* Very unlikely, but not a partition */
> return 0;
> if (errno == ENXIO || errno == ENOTTY)
> /* not a partition */
> return 0;
>
> return 1;
> }
>
> I plugged in with debugger and established that when ioctl is run on
> dm-device errno is EINVAL, as if it was a partition.
This is a known regression, reported here:
https://lore.kernel.org/all/CAOYeF9VsmqKMcQjo1k6YkGNujwN-nzfxY17N3F-CMikE1tYp+w@mail.gmail.com/
please try this patch:
https://lore.kernel.org/all/20240118130401.792757-1-lilingfeng@huaweicloud.com/
Thanks,
Kuai
>
> The issue is reproducible only with newer kernels which leads me te
> believe there is a regression in device mapper. This code has been
> working stable for last 10+ years, which is another reason. I tested
> this on RHEL 8.9 with inbox 5.14 kernel and 6.5.7-1 I happen to have
> installed. The issue reproduced only on 6.5.7-1 kernel. I also observed
> same regression on stock Ubuntu 24.04 with inbox 6.6.0 kernel.
>
> Can you please point me to when it was introduced and are there any
> plans for fixing it?
>
> Thanks,
> Mateusz
>
> .
>
prev parent reply other threads:[~2024-03-25 2:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-21 9:17 regression: mdadm detects dm-device as partition Mateusz Kusiak
2024-03-25 2:41 ` Yu Kuai [this message]
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