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mount weirdness

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  mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-05 22:40 +0200
    Re: mount weirdness Andrei POPESCU <andreimpopescu@gmail.com> - 2019-08-06 08:10 +0200
      Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-06 17:10 +0200
        Re: mount weirdness rhkramer@gmail.com - 2019-08-06 17:40 +0200
          Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-06 19:40 +0200
            Re: mount weirdness Richard Hector <richard@walnut.gen.nz> - 2019-08-06 19:50 +0200
              Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-06 20:00 +0200
                Re: mount weirdness Richard Hector <richard@walnut.gen.nz> - 2019-08-06 20:20 +0200
        Re: mount weirdness Felix Miata <mrmazda@earthlink.net> - 2019-08-06 17:40 +0200
          Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-06 19:30 +0200
    Re: mount weirdness "Thomas Schmitt" <scdbackup@gmx.net> - 2019-08-06 17:40 +0200
      Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-06 19:20 +0200
        Re: mount weirdness David Wright <deblis@lionunicorn.co.uk> - 2019-08-06 20:50 +0200
          Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-07 19:50 +0200
            Re: mount weirdness Greg Wooledge <wooledg@eeg.ccf.org> - 2019-08-07 20:00 +0200
            Re: mount weirdness David Wright <deblis@lionunicorn.co.uk> - 2019-08-07 22:50 +0200
        Re: mount weirdness "Thomas Schmitt" <scdbackup@gmx.net> - 2019-08-06 21:00 +0200
          Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-07 20:00 +0200
            Re: mount weirdness "Thomas Schmitt" <scdbackup@gmx.net> - 2019-08-07 23:30 +0200
    Re: mount weirdness Curt <curty@free.fr> - 2019-08-08 10:20 +0200
      Re: mount weirdness Curt <curty@free.fr> - 2019-08-08 10:50 +0200
        Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-09 21:20 +0200
      Re: mount weirdness "Thomas Schmitt" <scdbackup@gmx.net> - 2019-08-08 12:00 +0200
        Re: mount weirdness Curt <curty@free.fr> - 2019-08-08 14:40 +0200
        Re: mount weirdness Michael Stone <mstone@debian.org> - 2019-08-08 14:40 +0200
          Re: mount weirdness Curt <curty@free.fr> - 2019-08-08 15:00 +0200
      Re: mount weirdness David Wright <deblis@lionunicorn.co.uk> - 2019-08-08 16:10 +0200
        Re: mount weirdness Michael Stone <mstone@debian.org> - 2019-08-08 17:00 +0200
          Re: mount weirdness David Wright <deblis@lionunicorn.co.uk> - 2019-08-08 19:10 +0200
            Re: mount weirdness Greg Wooledge <wooledg@eeg.ccf.org> - 2019-08-08 19:20 +0200
            Re: mount weirdness Michael Stone <mstone@debian.org> - 2019-08-08 20:20 +0200
              Re: mount weirdness David Wright <deblis@lionunicorn.co.uk> - 2019-08-09 18:30 +0200
                Re: mount weirdness Greg Wooledge <wooledg@eeg.ccf.org> - 2019-08-09 19:00 +0200
                  Re: mount weirdness "Thomas Schmitt" <scdbackup@gmx.net> - 2019-08-09 20:00 +0200
        Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-09 22:00 +0200
      Re: mount weirdness Dennis Wicks <wix@mgssub.com> - 2019-08-09 21:20 +0200

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#212411

On 2019-08-08, Curt <curty@free.fr> wrote:
> On 2019-08-05, Dennis Wicks <wix@mgssub.com> wrote:
>>
>>
>> So anyway, I typed in "sudo mount /dev/sdb2 /wa1" and it 
>> seemed to finish successfully, but "ls /wa1" indicated that 
>> in fact it had not. Nothing mounted on wa1! Many other tests 
>> told me the same thing. "umount /wa1" said "not mounted"!
>
> Would this be the result if /dev/sdb2 were already mounted (i.e. nothing?).
>
> Many other tests. What about 'mount' from an xterm to see what's mounted
> and what ain't and where?
>
> Did you show your /etc/fstab file (cut and paste)? If so, I must've missed
> it.
>
> BTW, what's with the exclamation points? Makes you seem enthusiastic.
>
> ;-)
>

Oh, and I forgot: the relevant logs might be clueful and relevant
and of course should be explored for relevant clues.

-- 
“We are all in the gutter, but some of us are looking at the stars.” 
― Oscar Wilde, Lady Windermere's Fan

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#212533

Curt wrote on 8/8/19 3:41 AM:
> On 2019-08-08, Curt <curty@free.fr> wrote:
>> On 2019-08-05, Dennis Wicks <wix@mgssub.com> wrote:
>>>
>>>
>>> So anyway, I typed in "sudo mount /dev/sdb2 /wa1" and it
>>> seemed to finish successfully, but "ls /wa1" indicated that
>>> in fact it had not. Nothing mounted on wa1! Many other tests
>>> told me the same thing. "umount /wa1" said "not mounted"!
>>
>> Would this be the result if /dev/sdb2 were already mounted (i.e. nothing?).
>>
>> Many other tests. What about 'mount' from an xterm to see what's mounted
>> and what ain't and where?
>>
>> Did you show your /etc/fstab file (cut and paste)? If so, I must've missed
>> it.
>>
>> BTW, what's with the exclamation points? Makes you seem enthusiastic.
>>
>> ;-)
>>
> 
> Oh, and I forgot: the relevant logs might be clueful and relevant
> and of course should be explored for relevant clues.
> 
Tell me what logs and how to view them.

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#212418

Hi,

Curt wrote:
> Did you show your /etc/fstab file (cut and paste)? If so, I must've missed
> it.

See https://lists.debian.org/debian-user/2019/08/msg00295.html
where the attachments are kindly attached to the body text.

Results from "mount" without arguments or the contents of /etc/mtab
and /proc/mounts seem indeed not yet shown.

The central riddle is how mount(8) can fail to make the filesystem
available without visibly reporting an error.
A question about "mount -v" and its exit value is pending.
Maybe one should also look at dmesg output after such a silent failure.


Have a nice day :)

Thomas

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#212427

On 2019-08-08, Thomas Schmitt <scdbackup@gmx.net> wrote:
> Hi,
>
> The central riddle is how mount(8) can fail to make the filesystem
> available without visibly reporting an error.


Nothing to do with these swaps spaces (I took a gander at the /etc/fstab)?

 /wa1/Swap5 ...          
 /wa2/Swap6 ...    

 "I can mount /dev/sdb2 on any mount point except /wa1 and 2)" says the
 OP.

There's also a /wa3/Swap4, so maybe not. I wonder what happens if you
try to mount a partition on ... well.

> A question about "mount -v" and its exit value is pending.
> Maybe one should also look at dmesg output after such a silent failure.
>
>
> Have a nice day :)
>
> Thomas
>
>


-- 
“We are all in the gutter, but some of us are looking at the stars.” 
― Oscar Wilde, Lady Windermere's Fan

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#212428

On Thu, Aug 08, 2019 at 11:52:41AM +0200, Thomas Schmitt wrote:
>The central riddle is how mount(8) can fail to make the filesystem
>available without visibly reporting an error.
>A question about "mount -v" and its exit value is pending.
>Maybe one should also look at dmesg output after such a silent failure.

Yes, there are often messages in dmesg which do not appear in the mount 
output. I don't think the kernel API for mount passes those to the 
caller. I'd want to see that, and also the filesytem type (which, if 
mentioned, got lost in this wandering thread).

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#212430

On 2019-08-08, Michael Stone <mstone@debian.org> wrote:
> On Thu, Aug 08, 2019 at 11:52:41AM +0200, Thomas Schmitt wrote:
>>The central riddle is how mount(8) can fail to make the filesystem
>>available without visibly reporting an error.
>>A question about "mount -v" and its exit value is pending.
>>Maybe one should also look at dmesg output after such a silent failure.
>
> Yes, there are often messages in dmesg which do not appear in the mount 
> output. I don't think the kernel API for mount passes those to the 
> caller. I'd want to see that, and also the filesytem type (which, if 
> mentioned, got lost in this wandering thread).
>
>


sdb2 xfs      Work-Area-1  20173008-eeaa-41cd-b862-f7d0b871895d  241.9G    65% /wa11

-- 
“We are all in the gutter, but some of us are looking at the stars.” 
― Oscar Wilde, Lady Windermere's Fan

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#212440

On Thu 08 Aug 2019 at 08:19:22 (-0000), Curt wrote:
> On 2019-08-05, Dennis Wicks <wix@mgssub.com> wrote:
> > So anyway, I typed in "sudo mount /dev/sdb2 /wa1" and it 
> > seemed to finish successfully, but "ls /wa1" indicated that 
> > in fact it had not. Nothing mounted on wa1! Many other tests 
> > told me the same thing. "umount /wa1" said "not mounted"!
> 
> Would this be the result if /dev/sdb2 were already mounted (i.e. nothing?).

Try it. I, at least, would be interested in the result.
So far, the voting is 2-1 against seeing what I see:

wren 08:50:11 ~# lsblk -f | grep sda7
├─sda7       ext4        swan07      4a4e352f-2180-4083-92b4-f46e4e0104b4 /wrenbk
wren 08:50:26 ~# mkdir /wa1 /somethingelse
wren 08:50:49 ~# mount /dev/sda7 /somethingelse
mount: /dev/sda7 is already mounted or /somethingelse busy
       /dev/sda7 is already mounted on /wrenbk
32 wren 08:51:16 ~# mount /dev/sda7 /wa1
mount: /dev/sda7 is already mounted or /wa1 busy
       /dev/sda7 is already mounted on /wrenbk
32 wren 08:51:31 ~# rmdir /wa1 /somethingelse
wren 08:51:53 ~# 

By way of explanation, the prompt is
export PROMPT_COMMAND='MYPROMPT="$? " && [ "$MYPROMPT" = "0 " ] && MYPROMPT=""'
export PS1='\[\e[1;33;41m\]$MYPROMPT\[\e[1;37;44m\]\H \t \w\[\e[0m\]\$ ' # blue
but I normally cut it to reduce clutter.

> Many other tests. What about 'mount' from an xterm to see what's mounted
> and what ain't and where?
> 
> Did you show your /etc/fstab file (cut and paste)? If so, I must've missed
> it.
> 
> BTW, what's with the exclamation points? Makes you seem enthusiastic.

Yes, I couldn't figure that out, nor what good a note in /etc/fstab
would do (in the reply to Thomas). Does one peruse that file each time
one reboots?

Cheers,
David.

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#212446

On Thu, Aug 08, 2019 at 09:04:00AM -0500, David Wright wrote:
>wren 08:50:11 ~# lsblk -f | grep sda7
>├─sda7       ext4        swan07      4a4e352f-2180-4083-92b4-f46e4e0104b4 /wrenbk
>wren 08:50:26 ~# mkdir /wa1 /somethingelse
>wren 08:50:49 ~# mount /dev/sda7 /somethingelse
>mount: /dev/sda7 is already mounted or /somethingelse busy
>       /dev/sda7 is already mounted on /wrenbk
>32 wren 08:51:16 ~# mount /dev/sda7 /wa1
>mount: /dev/sda7 is already mounted or /wa1 busy
>       /dev/sda7 is already mounted on /wrenbk
>32 wren 08:51:31 ~# rmdir /wa1 /somethingelse
>wren 08:51:53 ~#

It's already been said repeatedly that you should post the bottom of 
dmesg output because kernel mount errors show up there but not in the 
output of the mount command. 

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#212453

[Multipart message — attachments visible in raw view] — view raw

On Thu 08 Aug 2019 at 10:56:46 (-0400), Michael Stone wrote:
> On Thu, Aug 08, 2019 at 09:04:00AM -0500, David Wright wrote:
> > wren 08:50:11 ~# lsblk -f | grep sda7
> > ├─sda7       ext4        swan07      4a4e352f-2180-4083-92b4-f46e4e0104b4 /wrenbk
> > wren 08:50:26 ~# mkdir /wa1 /somethingelse
> > wren 08:50:49 ~# mount /dev/sda7 /somethingelse
> > mount: /dev/sda7 is already mounted or /somethingelse busy
> >       /dev/sda7 is already mounted on /wrenbk
> > 32 wren 08:51:16 ~# mount /dev/sda7 /wa1
> > mount: /dev/sda7 is already mounted or /wa1 busy
> >       /dev/sda7 is already mounted on /wrenbk
> > 32 wren 08:51:31 ~# rmdir /wa1 /somethingelse
> > wren 08:51:53 ~#
> 
> It's already been said repeatedly that you should post the bottom of
> dmesg output because kernel mount errors show up there but not in the
> output of the mount command.

I've plenty of mount errors, which you've quoted, so I think you might
be addressing somebody else. Or have I missed something? But anyway,
dmesg's tail is attached, with a timecheck from earlier in the file so
that you can exercise forensic skills in tying the times above to
those in dmesg.

But the 2-1 vote wasn't whether error messages were emitted, but
whether the system should mount an already-mounted partition onto
another mount point. I get error messages and the mount fails.
Others get no error messages (though they haven't demonstrated
the lack) and a successful mount, so currently I'm in a minority
of one.

Cheers,
David.

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#212454

On Thu, Aug 08, 2019 at 12:09:11PM -0500, David Wright wrote:
> But the 2-1 vote wasn't whether error messages were emitted, but
> whether the system should mount an already-mounted partition onto
> another mount point. I get error messages and the mount fails.
> Others get no error messages (though they haven't demonstrated
> the lack) and a successful mount, so currently I'm in a minority
> of one.

It may very well depend on the version of Debian, the kernel, the mount
package, the type of file system... I don't know.  I was utterly surprised
when I got the result that I got, because I really did expect it to fail
with an error message.  I was in the process of writing an email reply of
the form "you can't do that, you have to use --bind or something".  I
tested it out, so I could paste the results into the email... and... this.

Here's what I get, on buster, amd64, standard 4.19 kernel, standard
mount package, ext4 file system, no encryption, no LVM, no mdraid.

wooledg:~$ df
Filesystem     1K-blocks     Used Available Use% Mounted on
udev             4007532        0   4007532   0% /dev
tmpfs             804828     2432    802396   1% /run
/dev/sda6      187064220 19717412 157821460  12% /
tmpfs            4024136   130088   3894048   4% /dev/shm
tmpfs               5120        0      5120   0% /run/lock
tmpfs            4024136        0   4024136   0% /sys/fs/cgroup
/dev/sda3        2818080    80600   2574616   4% /boot
tmpfs             804824       12    804812   1% /run/user/563
wooledg:~$ sudo mount /dev/sda3 /mnt
[sudo] password for wooledg: 
wooledg:~$ df
Filesystem     1K-blocks     Used Available Use% Mounted on
udev             4007532        0   4007532   0% /dev
tmpfs             804828     2432    802396   1% /run
/dev/sda6      187064220 19717412 157821460  12% /
tmpfs            4024136   130068   3894068   4% /dev/shm
tmpfs               5120        0      5120   0% /run/lock
tmpfs            4024136        0   4024136   0% /sys/fs/cgroup
/dev/sda3        2818080    80600   2574616   4% /mnt
tmpfs             804824       12    804812   1% /run/user/563
wooledg:~$ ls /mnt
config-4.19.0-5-amd64      initrd.img-4.9.0-8-amd64   vmlinuz-4.19.0-5-amd64
config-4.9.0-8-amd64       lost+found                 vmlinuz-4.9.0-8-amd64
grub                       System.map-4.19.0-5-amd64
initrd.img-4.19.0-5-amd64  System.map-4.9.0-8-amd64
wooledg:~$ ls /boot
config-4.19.0-5-amd64      initrd.img-4.9.0-8-amd64   vmlinuz-4.19.0-5-amd64
config-4.9.0-8-amd64       lost+found                 vmlinuz-4.9.0-8-amd64
grub                       System.map-4.19.0-5-amd64
initrd.img-4.19.0-5-amd64  System.map-4.9.0-8-amd64
wooledg:~$ sudo umount /mnt
wooledg:~$ df
Filesystem     1K-blocks     Used Available Use% Mounted on
udev             4007532        0   4007532   0% /dev
tmpfs             804828     2432    802396   1% /run
/dev/sda6      187064220 19717412 157821460  12% /
tmpfs            4024136   130068   3894068   4% /dev/shm
tmpfs               5120        0      5120   0% /run/lock
tmpfs            4024136        0   4024136   0% /sys/fs/cgroup
/dev/sda3        2818080    80600   2574616   4% /boot
tmpfs             804824       12    804812   1% /run/user/563
wooledg:~$ ls /mnt
wooledg:~$ 

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#212455

On Thu, Aug 08, 2019 at 12:09:11PM -0500, David Wright wrote:
>On Thu 08 Aug 2019 at 10:56:46 (-0400), Michael Stone wrote:
>> On Thu, Aug 08, 2019 at 09:04:00AM -0500, David Wright wrote:
>> > wren 08:50:11 ~# lsblk -f | grep sda7
>> > ├─sda7       ext4        swan07      4a4e352f-2180-4083-92b4-f46e4e0104b4 /wrenbk
>> > wren 08:50:26 ~# mkdir /wa1 /somethingelse
>> > wren 08:50:49 ~# mount /dev/sda7 /somethingelse
>> > mount: /dev/sda7 is already mounted or /somethingelse busy
>> >       /dev/sda7 is already mounted on /wrenbk
>> > 32 wren 08:51:16 ~# mount /dev/sda7 /wa1
>> > mount: /dev/sda7 is already mounted or /wa1 busy
>> >       /dev/sda7 is already mounted on /wrenbk
>> > 32 wren 08:51:31 ~# rmdir /wa1 /somethingelse
>> > wren 08:51:53 ~#
>>
>> It's already been said repeatedly that you should post the bottom of
>> dmesg output because kernel mount errors show up there but not in the
>> output of the mount command.
>
>I've plenty of mount errors, which you've quoted, so I think you might
>be addressing somebody else. Or have I missed something? But anyway,
>dmesg's tail is attached, with a timecheck from earlier in the file so
>that you can exercise forensic skills in tying the times above to
>those in dmesg.

No, I'm addressing you. It's very common for mount to say something like 
"can't do that" but you need a kernel error message to explain why 
because the kernel mount API isn't verbose. (As I said in a previous 
message.) Example:

# mount -o norecovery,loop test.img /mnt
mount: /mnt: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
# dmesg | tail -n 1
[268039.035599] XFS (loop0): no-recovery mounts must be read-only.

In this case the dmesg output doesn't add anything, but it's generally 
good for completeness. 

>But the 2-1 vote wasn't whether error messages were emitted, but
>whether the system should mount an already-mounted partition onto
>another mount point. I get error messages and the mount fails.
>Others get no error messages (though they haven't demonstrated
>the lack) and a successful mount, so currently I'm in a minority
>of one.

That's not a matter for voting, it's something that was implemented 
years ago, in the 2.4 kernel:

potato:~# uname -a
Linux potato 2.2.19-idepci #1 Wed Mar 20 20:33:20 EST 2002 i686 unknown
potato:~# mount
/dev/hda1 on / type ext2 (rw,errors=remount-ro,errors=remount-ro)
proc on /proc type proc (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
potato:~# mount /dev/hda1 /mnt
mount: /dev/hda1 already mounted or /mnt busy
mount: according to mtab, /dev/hda1 is mounted on /

woody:~# uname -a
Linux woody 2.4.18-686-smp #1 SMP Sun Apr 14 12:07:19 EST 2002 i686 unknown
woody:~# mount
/dev/hda1 on / type ext2 (rw,errors=remount-ro)
proc on /proc type proc (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
woody:~# mount /dev/hda1 /mnt
woody:~# ls /mnt
bin  boot  cdrom  dev  etc  floppy  home  initrd  initrd.img  lib  lost+found  mnt  opt  proc  root  sbin  tmp	usr  var  vmlinuz  vmlinuz.old

So you're confusing a completely different issue with something fairly 
unique to your system. I'm not sure if you've somehow managed to turn 
that off via a switch that I'm just not familiar with, or if there's 
something else going on. There's a reference to dm in your dmesg, so 
possibly a dm driver is grabbing your block device and preventing 
multiple access. There are a few other possibilities, but suffice it to 
say that they aren't typical.

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#212518

Sorry to cause the thread to "wander", but some of us are trying to
replicate aspects of the OP's problem, which necessitates explaining
any differences in the results being obtained.

On Thu 08 Aug 2019 at 14:14:25 (-0400), Michael Stone wrote:
> On Thu, Aug 08, 2019 at 12:09:11PM -0500, David Wright wrote:
> > On Thu 08 Aug 2019 at 10:56:46 (-0400), Michael Stone wrote:
> > > On Thu, Aug 08, 2019 at 09:04:00AM -0500, David Wright wrote:
> > > > wren 08:50:11 ~# lsblk -f | grep sda7
> > > > ├─sda7       ext4        swan07      4a4e352f-2180-4083-92b4-f46e4e0104b4 /wrenbk
> > > > wren 08:50:26 ~# mkdir /wa1 /somethingelse
> > > > wren 08:50:49 ~# mount /dev/sda7 /somethingelse
> > > > mount: /dev/sda7 is already mounted or /somethingelse busy
> > > >       /dev/sda7 is already mounted on /wrenbk
> > > > 32 wren 08:51:16 ~# mount /dev/sda7 /wa1
> > > > mount: /dev/sda7 is already mounted or /wa1 busy
> > > >       /dev/sda7 is already mounted on /wrenbk
> > > > 32 wren 08:51:31 ~# rmdir /wa1 /somethingelse
> > > > wren 08:51:53 ~#
> > > 
> > > It's already been said repeatedly that you should post the bottom of
> > > dmesg output because kernel mount errors show up there but not in the
> > > output of the mount command.
> > 
> > I've plenty of mount errors, which you've quoted, so I think you might
> > be addressing somebody else. Or have I missed something? But anyway,
> > dmesg's tail is attached, with a timecheck from earlier in the file so
> > that you can exercise forensic skills in tying the times above to
> > those in dmesg.
> 
> No, I'm addressing you. It's very common for mount to say something
> like "can't do that" but you need a kernel error message to explain
> why because the kernel mount API isn't verbose. (As I said in a
> previous message.) Example:
> 
> # mount -o norecovery,loop test.img /mnt
> mount: /mnt: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
> # dmesg | tail -n 1
> [268039.035599] XFS (loop0): no-recovery mounts must be read-only.
> 
> In this case the dmesg output doesn't add anything, but it's generally
> good for completeness.

Well I wasn't aware that dmesg specifically added anything to what I
see as a matter of course: I have an xconsole at the foot of the page
and an xterm running tail -F /var/log/kern.log in my diagnostics
viewport.

But your incidental choice of example has nudged me in the right
direction; seeing the string "read-only", I tried:

# mkdir /somethingelse
# mount /dev/sda7 /somethingelse
mount: /dev/sda7 is already mounted or /somethingelse busy
       /dev/sda7 is already mounted on /wrenbk
# mount -o ro /dev/sda7 /somethingelse
# 

and bingo. /wrenbk is the backup installation on this laptop.
I normally mount them readonly so that I can't accidentally interfere
with them. So it appears that any subsequent mount commands have to
agree explicitly with the earlier choice. Are there other, similar
factors involved in the OP's case…

Looking at the OP's fstab, regardless of what worked in the past,
I would reorganise it into a more systematic order. I got caught out
when systemd came out, because my fstab had two entries for the
same mountpoint. SystemV just churns through fstab carrying out
its mount, whereas systemd reads the whole file (and regurgitates it?)
before it mounts anything.

So what's the explanation for entries such as these:

/wa3/Swap4   none swap sw,pri=100,nofail,x-systemd.device-timeout=60
/wa1/Swap5   none swap sw,pri=100,nofail,x-systemd.device-timeout=60
/wa2/Swap6   none swap sw,pri=100,nofail,x-systemd.device-timeout=60
/pvt04/Swap7 none swap sw,pri=100,nofail,x-systemd.device-timeout=60

UUID=20173008-…   /wa11  xfs defaults,nofail,x-systemd.device-timeout=20 ¹
UUID=9092610b-…   /wa2   xfs defaults,nofail,x-systemd.device-timeout=60
LABEL=Work-Area-3 /wa3   xfs defaults,nofail,x-systemd.device-timeout=60
UUID=fdbb6809-…   /pvt04 xfs defaults,nofail,x-systemd.device-timeout=60

¹ was /wa1 originally.

Is it intended that the "General work areas" hide these swap files,
or is this just the way the OP's fstab grew? It's not clear to me
what the semantics for systemd.mount are, but a first reading
suggests that it contradicts fstab.

And rereading the first OP, what is Debian 10 bullseye?
Is all this just an ephemeral bug that will disappear next week?

> > But the 2-1 vote wasn't whether error messages were emitted, but
> > whether the system should mount an already-mounted partition onto
> > another mount point. I get error messages and the mount fails.
> > Others get no error messages (though they haven't demonstrated
> > the lack) and a successful mount, so currently I'm in a minority
> > of one.
> 
> That's not a matter for voting, it's something that was implemented
> years ago, in the 2.4 kernel:

Sorry, badly expressed: by "voting", I just meant OP & Greg (2) report
successful mounts, and I (1) an error message.

Whether I like the ability to mount in this manner, I'm with Greg at the
moment. Obviously I missed any discussion on the topic ~15 years ago,
so I haven't seen any benefits spelled out. In any case, perhaps a
warning in kern.log rather than total silence? After all, mount already
warns about things like:

    "utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!"
    "Volume was not properly unmounted. Some data may be corrupt. Please run fsck."

Cheers,
David.

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#212522

On Fri, Aug 09, 2019 at 11:29:17AM -0500, David Wright wrote:
> Whether I like the ability to mount in this manner, I'm with Greg at the
> moment. Obviously I missed any discussion on the topic ~15 years ago,
> so I haven't seen any benefits spelled out. In any case, perhaps a
> warning in kern.log rather than total silence?

The disappearance of one of the mounts from "df" output also tells me
that, if nothing else, "df" is not prepared to handle this situation.
I wonder what other userspace commands might be making assumptions
about things that are no longer true.

I also wonder whether this is a bug in df.

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#212527

Hi,

David Wright wrote:
> it appears that any subsequent mount commands have to
> agree explicitly with the earlier choice. Are there other, similar
> factors involved in the OP's case…

Ah yes.

I was similarly confused by my system's behavior on double mount
and the fact that i remember to have needed mount -o loop for mounting
two different ISO 9660 sessions on the same DVD.

It seems that identical multi-mounts actually work like links to the
same filesystem:

  # mount /dev/sdc2 /mnt/fat
  # mount /dev/sdc2 /mnt/fat2
  # echo hallo >/mnt/fat/x
  # cat /mnt/fat/x
  hallo
  # cat /mnt/fat2/x
  hallo


Greg Wooledge wrote:
> The disappearance of one of the mounts from "df" output also tells me
> that, if nothing else, "df" is not prepared to handle this situation.

Or it avoids intentionally to represent one mounted filesystem as two.
The code starting at
  https://sources.debian.org/src/coreutils/8.30-3/src/df.c/#L688
looks like considerations for possibly doing one of:
  /* Discard mount entry for existing device.  */
  /* Discard mount entry currently being processed.  */

---------------------------------------------------------------------

But again, this is a deviation from the problem.

Why does mount fail silently ?
Why is bad luck attached only to the mount directory path /wa1 ?

(Is the problem bound to mount(8) or does it sit in mount(2) ?)


Have a nice day :)

Thomas

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#212535

David Wright wrote on 8/8/19 9:04 AM:
> On Thu 08 Aug 2019 at 08:19:22 (-0000), Curt wrote:
>> On 2019-08-05, Dennis Wicks <wix@mgssub.com> wrote:
>>> So anyway, I typed in "sudo mount /dev/sdb2 /wa1" and it
>>> seemed to finish successfully, but "ls /wa1" indicated that
>>> in fact it had not. Nothing mounted on wa1! Many other tests
>>> told me the same thing. "umount /wa1" said "not mounted"!
>>
>> Would this be the result if /dev/sdb2 were already mounted (i.e. nothing?).
> 
> Try it. I, at least, would be interested in the result.
> So far, the voting is 2-1 against seeing what I see:
> 
> wren 08:50:11 ~# lsblk -f | grep sda7
> ├─sda7       ext4        swan07      4a4e352f-2180-4083-92b4-f46e4e0104b4 /wrenbk
> wren 08:50:26 ~# mkdir /wa1 /somethingelse
> wren 08:50:49 ~# mount /dev/sda7 /somethingelse
> mount: /dev/sda7 is already mounted or /somethingelse busy
>         /dev/sda7 is already mounted on /wrenbk
> 32 wren 08:51:16 ~# mount /dev/sda7 /wa1
> mount: /dev/sda7 is already mounted or /wa1 busy
>         /dev/sda7 is already mounted on /wrenbk
> 32 wren 08:51:31 ~# rmdir /wa1 /somethingelse
> wren 08:51:53 ~#
> 
> By way of explanation, the prompt is
> export PROMPT_COMMAND='MYPROMPT="$? " && [ "$MYPROMPT" = "0 " ] && MYPROMPT=""'
> export PS1='\[\e[1;33;41m\]$MYPROMPT\[\e[1;37;44m\]\H \t \w\[\e[0m\]\$ ' # blue
> but I normally cut it to reduce clutter.
> 
>> Many other tests. What about 'mount' from an xterm to see what's mounted
>> and what ain't and where?
>>
>> Did you show your /etc/fstab file (cut and paste)? If so, I must've missed
>> it.
>>
>> BTW, what's with the exclamation points? Makes you seem enthusiastic.
> 
> Yes, I couldn't figure that out, nor what good a note in /etc/fstab
> would do (in the reply to Thomas). Does one peruse that file each time
> one reboots?
> 
> Cheers,
> David.
> 
> 
Greetings;

What system are you running, David? I am running vanilla 
Debian bullseye, recently upgraded. Been running Debian for 
years and have never gotten those errors. This is what 
happens to me.

  wix@dgwicks:~$ s mount /dev/sdc1 /test1
  wix@dgwicks:~$ s mount /dev/sdc1 /test2
  wix@dgwicks:~$ findmnt /dev/sdc1
  TARGET SOURCE    FSTYPE OPTIONS
  /test1 /dev/sdc1 xfs    rw,relatime,attr2,inode64,noquota
  /test2 /dev/sdc1 xfs    rw,relatime,attr2,inode64,noquota
  wix@dgwicks:~$
  wix@dgwicks:~$ s mount -v /dev/sdc1 /work-1
  mount: /dev/sdc1 mounted on /work-1.
  wix@dgwicks:~$ findmnt /dev/sdc1
  TARGET  SOURCE    FSTYPE OPTIONS
  /test1  /dev/sdc1 xfs    rw,relatime,attr2,inode64,noquota
  /test2  /dev/sdc1 xfs    rw,relatime,attr2,inode64,noquota
  /work-1 /dev/sdc1 xfs    rw,relatime,attr2,inode64,noquota
  wix@dgwicks:~$

Do you have some environment variable set or something in an 
ini or rc file that makes mount behave in a more strict way 
than standard?

No, I don't look at fstab every time I reboot. Just when I 
get things like failed mounts. In which case seeing that 
note will remind me what to look at/for.

Regards,
Dennis

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#212532

Curt wrote on 8/8/19 3:19 AM:
> On 2019-08-05, Dennis Wicks <wix@mgssub.com> wrote:
>>
>>
>> So anyway, I typed in "sudo mount /dev/sdb2 /wa1" and it
>> seemed to finish successfully, but "ls /wa1" indicated that
>> in fact it had not. Nothing mounted on wa1! Many other tests
>> told me the same thing. "umount /wa1" said "not mounted"!
> 
> Would this be the result if /dev/sdb2 were already mounted (i.e. nothing?).
System does not care if device is already mounted somewhere 
else.


> 
> Many other tests. What about 'mount' from an xterm to see what's mounted
> and what ain't and where?
> 
> Did you show your /etc/fstab file (cut and paste)? If so, I must've missed
> it.
Yep. Sometime back.
> 
> BTW, what's with the exclamation points? Makes you seem enthusiastic.
Nope. Surprised!
> 
> ;-)
> 
> 

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