[linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[Gang He]

Hello List,

One user complained this error message.
The user has a usb sd card reader with no media present.  When they issue a pvscan under lvm2-2.02.180 the device is opened which results in 'No medium found' being reported. 
But lvm2-2.02.120 did not do this (the device appears to get filtered out earlier). The customer views the 'No medium found' message as an issue/bug.
Any suggest/comments for this error message?

The detailed information is as below,
lvm2 2.02.180-9.4.2
OS: SLES12 SP4
Kernel 4.12.14-95.3-default
Hardware: HP ProLiant DL380 Gen10

After upgrade from sles12SP3 to SP4, customer is reporting the following error message:

 # pvscan
 /dev/sdc: open failed: No medium found
 PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
 Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]


Thanks
Gang

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[David Teigland]

On Mon, Apr 22, 2019 at 11:15:53PM -0600, Gang He wrote:
> Hello List,
> 
> One user complained this error message.
> The user has a usb sd card reader with no media present.  When they issue a pvscan under lvm2-2.02.180 the device is opened which results in 'No medium found' being reported. 
> But lvm2-2.02.120 did not do this (the device appears to get filtered out earlier). The customer views the 'No medium found' message as an issue/bug.
> Any suggest/comments for this error message?
> 
> The detailed information is as below,
> lvm2 2.02.180-9.4.2
> OS: SLES12 SP4
> Kernel 4.12.14-95.3-default
> Hardware: HP ProLiant DL380 Gen10
> 
> After upgrade from sles12SP3 to SP4, customer is reporting the following error message:
> 
>  # pvscan
>  /dev/sdc: open failed: No medium found
>  PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
>  Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]

I've heard this a few times now, I guess we should drop it, it's probably
more trouble than help.

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[Peter Rajnoha]

On 4/23/19 7:15 AM, Gang He wrote:
> Hello List,
> 
> One user complained this error message.
> The user has a usb sd card reader with no media present.  When they issue a pvscan under lvm2-2.02.180 the device is opened which results in 'No medium found' being reported. 
> But lvm2-2.02.120 did not do this (the device appears to get filtered out earlier). The customer views the 'No medium found' message as an issue/bug.
> Any suggest/comments for this error message?
> 
> The detailed information is as below,
> lvm2 2.02.180-9.4.2
> OS: SLES12 SP4
> Kernel 4.12.14-95.3-default
> Hardware: HP ProLiant DL380 Gen10
> 
> After upgrade from sles12SP3 to SP4, customer is reporting the following error message:
> 
>  # pvscan
>  /dev/sdc: open failed: No medium found
>  PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
>  Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]
> 
> 

See also https://github.com/lvmteam/lvm2/issues/13

-- 
Peter

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[Gang He]

Hello Peter and David,

Thank for your quick responses.
How do we handle this behavior further?
Fix it as an issue, filter this kind of disk silently. 
or keep the current error message printing, looking a bit unfriendly, but the logic is not wrong.


Thanks
Gang




>>> On 2019/4/23 at 23:24, in message
<9cd91b48-408b-f7a9-c4bc-df05d55376e6@redhat.com>, Peter Rajnoha
<prajnoha@redhat.com> wrote:
> On 4/23/19 7:15 AM, Gang He wrote:
>> Hello List,
>> 
>> One user complained this error message.
>> The user has a usb sd card reader with no media present.  When they issue a 
> pvscan under lvm2-2.02.180 the device is opened which results in 'No medium 
> found' being reported. 
>> But lvm2-2.02.120 did not do this (the device appears to get filtered out 
> earlier). The customer views the 'No medium found' message as an issue/bug.
>> Any suggest/comments for this error message?
>> 
>> The detailed information is as below,
>> lvm2 2.02.180-9.4.2
>> OS: SLES12 SP4
>> Kernel 4.12.14-95.3-default
>> Hardware: HP ProLiant DL380 Gen10
>> 
>> After upgrade from sles12SP3 to SP4, customer is reporting the following 
> error message:
>> 
>>  # pvscan
>>  /dev/sdc: open failed: No medium found
>>  PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
>>  Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]
>> 
>> 
> 
> See also https://github.com/lvmteam/lvm2/issues/13 
> 
> -- 
> Peter
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com 
> https://www.redhat.com/mailman/listinfo/linux-lvm 
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[Zdenek Kabelac]

Dne 23. 04. 19 v 16:27 David Teigland napsal(a):
> On Mon, Apr 22, 2019 at 11:15:53PM -0600, Gang He wrote:
>> Hello List,
>>
>> One user complained this error message.
>> The user has a usb sd card reader with no media present.  When they issue a pvscan under lvm2-2.02.180 the device is opened which results in 'No medium found' being reported.
>> But lvm2-2.02.120 did not do this (the device appears to get filtered out earlier). The customer views the 'No medium found' message as an issue/bug.
>> Any suggest/comments for this error message?
>>
>> The detailed information is as below,
>> lvm2 2.02.180-9.4.2
>> OS: SLES12 SP4
>> Kernel 4.12.14-95.3-default
>> Hardware: HP ProLiant DL380 Gen10
>>
>> After upgrade from sles12SP3 to SP4, customer is reporting the following error message:
>>
>>   # pvscan
>>   /dev/sdc: open failed: No medium found
>>   PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
>>   Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]
> 
> I've heard this a few times now, I guess we should drop it, it's probably
> more trouble than help.
> 

This hotfix patch:

https://www.redhat.com/archives/lvm-devel/2019-April/msg00067.html

is unfortunately faulty and should be reverted.

The core problem is - the filtering layer is somehow bypassed where cdrom used 
be recognized as unsuitable device for opening.

So the error reported by lvm2 is really an error where lvm2 should not be 
trying to even open such device.

The switch of message severity not only 'waves' this particular  cdrom open 
error - but also all other device open errors.


Zdenek

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[David Teigland]

On Wed, Apr 24, 2019 at 10:37:26AM +0200, Zdenek Kabelac wrote:
> Dne 23. 04. 19 v 16:27 David Teigland napsal(a):
> > On Mon, Apr 22, 2019 at 11:15:53PM -0600, Gang He wrote:
> > > Hello List,
> > > 
> > > One user complained this error message.
> > > The user has a usb sd card reader with no media present.  When they issue a pvscan under lvm2-2.02.180 the device is opened which results in 'No medium found' being reported.
> > > But lvm2-2.02.120 did not do this (the device appears to get filtered out earlier). The customer views the 'No medium found' message as an issue/bug.
> > > Any suggest/comments for this error message?
> > > 
> > > The detailed information is as below,
> > > lvm2 2.02.180-9.4.2
> > > OS: SLES12 SP4
> > > Kernel 4.12.14-95.3-default
> > > Hardware: HP ProLiant DL380 Gen10
> > > 
> > > After upgrade from sles12SP3 to SP4, customer is reporting the following error message:
> > > 
> > >   # pvscan
> > >   /dev/sdc: open failed: No medium found
> > >   PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
> > >   Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]
> > 
> > I've heard this a few times now, I guess we should drop it, it's probably
> > more trouble than help.
> > 
> 
> This hotfix patch:
> 
> https://www.redhat.com/archives/lvm-devel/2019-April/msg00067.html
> 
> is unfortunately faulty and should be reverted.
> 
> The core problem is - the filtering layer is somehow bypassed where cdrom
> used be recognized as unsuitable device for opening.
>
> So the error reported by lvm2 is really an error where lvm2 should not be
> trying to even open such device.

I don't believe opening is the problem; most filters need the device open.
I suspect the difference is that filter-usable once used
dev_open_readonly_quiet itself, which suppressed the warning, to use with
dev_get_size.  Now the filter relies on dev_get_size to open the dev if
necessary (it's often already open), and that does not use the quiet flag.

This might be an effective alternative to suppressing all open warnings
(I can't say for certain in this case until seeing which open triggered
the warning.)

diff --git a/lib/device/dev-io.c b/lib/device/dev-io.c
index 3fe264755443..bd6cbcb04a1b 100644
--- a/lib/device/dev-io.c
+++ b/lib/device/dev-io.c
@@ -165,7 +165,7 @@ static int _dev_get_size_dev(struct device *dev, uint64_t *size)
        }
 
        if (fd <= 0) {
-               if (!dev_open_readonly(dev))
+               if (!dev_open_readonly_quiet(dev))
                        return_0;
                fd = dev_fd(dev);
                do_close = 1;

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[Zdenek Kabelac]

Dne 24. 04. 19 v 17:35 David Teigland napsal(a):
> On Wed, Apr 24, 2019 at 10:37:26AM +0200, Zdenek Kabelac wrote:
>> Dne 23. 04. 19 v 16:27 David Teigland napsal(a):
>>> On Mon, Apr 22, 2019 at 11:15:53PM -0600, Gang He wrote:
>>>> Hello List,
>>>>
>>>> One user complained this error message.
>>>> The user has a usb sd card reader with no media present.  When they issue a pvscan under lvm2-2.02.180 the device is opened which results in 'No medium found' being reported.
>>>> But lvm2-2.02.120 did not do this (the device appears to get filtered out earlier). The customer views the 'No medium found' message as an issue/bug.
>>>> Any suggest/comments for this error message?
>>>>
>>>> The detailed information is as below,
>>>> lvm2 2.02.180-9.4.2
>>>> OS: SLES12 SP4
>>>> Kernel 4.12.14-95.3-default
>>>> Hardware: HP ProLiant DL380 Gen10
>>>>
>>>> After upgrade from sles12SP3 to SP4, customer is reporting the following error message:
>>>>
>>>>    # pvscan
>>>>    /dev/sdc: open failed: No medium found
>>>>    PV /dev/sdb   VG Q11vg10         lvm2 [5.24 TiB / 2.00 TiB free]
>>>>    Total: 1 [5.24 TiB] / in use: 1 [5.24 TiB] / in no VG: 0 [0   ]
>>>
>>> I've heard this a few times now, I guess we should drop it, it's probably
>>> more trouble than help.
>>>
>>
>> This hotfix patch:
>>
>> https://www.redhat.com/archives/lvm-devel/2019-April/msg00067.html
>>
>> is unfortunately faulty and should be reverted.
>>
>> The core problem is - the filtering layer is somehow bypassed where cdrom
>> used be recognized as unsuitable device for opening.
>>
>> So the error reported by lvm2 is really an error where lvm2 should not be
>> trying to even open such device.
> 
> I don't believe opening is the problem; most filters need the device open.
> I suspect the difference is that filter-usable once used
> dev_open_readonly_quiet itself, which suppressed the warning, to use with
> dev_get_size.  Now the filter relies on dev_get_size to open the dev if
> necessary (it's often already open), and that does not use the quiet flag.
> 
> This might be an effective alternative to suppressing all open warnings
> (I can't say for certain in this case until seeing which open triggered
> the warning.)


The core principle should be that lvm2 should always open minimal needed set 
of devices - and always use as much other system hints to avoid opening 
something we know it can't be a PV.

AKA in case of cdrom - it can cause annoying clicking sound - in some other 
cases opening of device that used to be filtered before can even cause unwated 
disk wake-up, delays and in some obscure case maybe even long delays.

So preferable fix is to correct list devices that are going to be opened.

Zdenek

Re: [linux-lvm] pvscan: /dev/sdc: open failed: No medium found

[Gang He]

Hello David,

Sorry for delayed reply.
the verbose log (lvm2-2.02.180) looks like,

#device/dev-cache.c:763           Found dev 11:0 /dev/disk/by-id/ata-TSSTcorp_DVDWBD_SH-B123L_R84A6GDC10003F - new alias.
#device/dev-cache.c:763           Found dev 11:0 /dev/disk/by-label/SLE-12-SP4-Server-DVD-x86_640456 - new alias.
#device/dev-cache.c:763           Found dev 11:0 /dev/disk/by-path/pci-0000:00:1f.2-ata-2 - new alias.
#device/dev-cache.c:763           Found dev 11:0 /dev/disk/by-uuid/2018-11-07-14-08-50-00 - new alias.
#device/dev-cache.c:763           Found dev 11:0 /dev/dvd - new alias.
#device/dev-cache.c:763           Found dev 11:0 /dev/dvdrw - new alias.
#cache/lvmetad.c:1420          Asking lvmetad for complete list of known PVs
#device/dev-io.c:609           Opened /dev/sda RO O_DIRECT
#device/dev-io.c:359         /dev/sda: size is 268435456 sectors
#device/dev-io.c:658           Closed /dev/sda
#filters/filter-partitioned.c:37            /dev/sda: Skipping: Partition table signature found
#filters/filter-type.c:27            /dev/cdrom: Skipping: Unrecognised LVM device type 11
#device/dev-io.c:609           Opened /dev/sda1 RO O_DIRECT
#device/dev-io.c:359         /dev/sda1: size is 4206592 sectors
#device/dev-io.c:658           Closed /dev/sda1
#filters/filter-mpath.c:196           /dev/sda1: Device is a partition, using primary device sda for mpath component detection
#device/dev-io.c:336         /dev/sda1: using cached size 4206592 sectors
#filters/filter-persistent.c:346           filter caching good /dev/sda1
#device/dev-io.c:609           Opened /dev/root RO O_DIRECT
#device/dev-io.c:359         /dev/root: size is 264226816 sectors
#device/dev-io.c:658           Closed /dev/root
#filters/filter-mpath.c:196           /dev/root: Device is a partition, using primary device sda for mpath component detection
#device/dev-io.c:336         /dev/root: using cached size 264226816 sectors
#filters/filter-persistent.c:346           filter caching good /dev/root
#device/dev-io.c:567     /dev/sdb: open failed: No medium found                    <<== here
#device/dev-io.c:343           <backtrace>
#filters/filter-usable.c:32            /dev/sdb: Skipping: dev_get_size failed
#toollib.c:4377          Processing PVs in VG #orphans_lvm2
#locking/locking.c:331           Dropping cache for #orphans.
#misc/lvm-flock.c:202         Locking /run/lvm/lock/P_orphans RB
#misc/lvm-flock.c:100           _do_flock /run/lvm/lock/P_orphans:aux WB
#misc/lvm-flock.c:47            _undo_flock /run/lvm/lock/P_orphans:aux
#misc/lvm-flock.c:100           _do_flock /run/lvm/lock/P_orphans RB
#cache/lvmcache.c:751           lvmcache has no info for vgname "#orphans".
#metadata/metadata.c:3764        Reading VG #orphans_lvm2
#locking/locking.c:331           Dropping cache for #orphans.
#misc/lvm-flock.c:70          Unlocking /run/lvm/lock/P_orphans
#misc/lvm-flock.c:47            _undo_flock /run/lvm/lock/P_orphans
#cache/lvmcache.c:751           lvmcache has no info for vgname "#orphans".
#locking/locking.c:331           Dropping cache for #orphans.

Thanks
Gang 

>>> On 4/24/2019 at 11:08 pm, in message <20190424150858.GA3218@redhat.com>, David
Teigland <teigland@redhat.com> wrote:
> On Tue, Apr 23, 2019 at 09:23:29PM -0600, Gang He wrote:
>> Hello Peter and David,
>> 
>> Thank for your quick responses.
>> How do we handle this behavior further?
>> Fix it as an issue, filter this kind of disk silently. 
>> or keep the current error message printing, looking a bit unfriendly, but 
> the logic is not wrong.
> 
> Hi, 
> 
> I'd like to figure out what the old code was doing differently to avoid
> this.  Part of the problem is that I don't have a device that reports
> these same errors.  Could you send me the output of pvscan -vvvv so I can
> see which open is causing the error?
> Thanks