reassign 669314 src:linux-2.6 3.2.15-1
found 669314 linux-2.6/3.3.2-1~experimental.1
quit

Hi,

Chris Hiestand wrote:

> I expect /proc/self/mounts to show (notice no trailing slash on the export):
> nfsserver:/srv/ubuntu-32 /mnt/ubuntu-32 nfs ro,nosuid,nodev,noatime,vers=3,rsize=32768,wsize=3 2768,namlen=255,soft,proto=tcp,timeo=600,retrans=2 ,sec=sys,mountaddr=198.202.1.1,mountvers=3,mountpo rt=41576,mountproto=tcp,local_lock=none,addr=198.2 02.1.1 0 0
>
> But instead in /proc/self/mounts I get (notice the trailing slash):
> nfsserver:/srv/ubuntu-32/ /mnt/ubuntu-32 nfs ro,nosuid,nodev,noatime,vers=3,rsize=32768,wsize=3 2768,namlen=255,soft,proto=tcp,timeo=600,retrans=2 ,sec=sys,mountaddr=198.202.1.1,mountvers=3,mountpo rt=41576,mountproto=tcp,local_lock=none,addr=198.2 02.1.1 0 0
>
> This simple change has a lot of implications because lots of things
> parse /proc/self/mounts, for example mount.nfs and umount.nfs
>
> user@hostname:/proc/self$ sudo umount.nfs nfsserver:/srv/ubuntu-32
> umount.nfs: nfsserver:/srv/ubuntu-32: not found
>
> And if you run "sudo mount -va", mount will not recognize that the
> fstab mounts have already been mounted; mounting all mounts twice on
> the same mount point. This quickly gets messy.
[...]
> As a workaround, I can boot into the squeeze kernel,
> linux-image-2.6.32-5-amd64, and the problem no longer reproduces.
> This is why I believe it is a problem in the kernel and not in
> nfs-common.

Laurent Désarmes wrote:

> I've been able to reproduce this bug.
> It doesn't happen when using nfs4, it does with nfsvers=2 or
> nfsvers=3.

Thanks for a clear report, and sorry for the slow response.

I suspect this behavior change was introduced by v2.6.39-rc1~460^2~3
(vfs: new superblock methods to override /proc/*/mount{s,info},
2011-03-16). Can you confirm, like so?

0. prerequisites:

apt-get install git build-essential

1. get the kernel history, if you don't already have it:

git clone
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

2. configure, build, test:

cd linux
git checkout v2.6.39-rc1~460^2~3
git checkout HEAD^
cp /boot/config-$(uname -r) .config; # current configuration
scripts/config --disable DEBUG_INFO
make localmodconfig; # optional: minimize configuration
make deb-pkg; # optionally with -j<num> for parallel build
dpkg -i ../<name of package>; # as root
reboot
... test test test ...

3. Hopefully it does not reproduce the bug. So try the patch:

cd linux
git checkout v2.6.39-rc1~460^2~3
make deb-pkg; # maybe with -j4
dpkg -i ../<name of package>; # as root
reboot
... test test test ...

An alternative way to confirm would be to try packages from before and
after that change from snapshot.debian.org.

I suspect that commit was just preparation for removing get_sb() and
was not supposed to change behavior, though I'm not sure.

Hope that helps,
Jonathan



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Hi again,

Quick correction:

Jonathan Nieder wrote:

> I suspect this behavior change was introduced by v2.6.39-rc1~460^2~3

I should have said v2.6.39-rc1~460^2^ (nfs: switch NFS from ->get_sb()
to ->mount(), 2011-03-16). So:

[...]
> apt-get install git build-essential
[...]
> git clone
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[...]
> cd linux
> git checkout v2.6.39-rc1~460^2~3
> git checkout HEAD^

This should say

git checkout v2.6.39-rc1~460^2^
git checkout HEAD^

[...]
> 3. Hopefully it does not reproduce the bug. So try the patch:
>
> cd linux
> git checkout v2.6.39-rc1~460^2~3
> make deb-pkg; # maybe with -j4

... and this one should say

git checkout v2.6.39-rc1~460^2^
make deb-pkg; # maybe with -j4

Thanks again, and sorry for the confusion.
Jonathan



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On Jun 17, 2012, at 3:31 PM, Jonathan Nieder wrote:

> I should have said v2.6.39-rc1~460^2^ (nfs: switch NFS from ->get_sb()
> to ->mount(), 2011-03-16). So:


Thanks Jonathan,

Based on this tip I tested that commit and neighboring commits and was
able to find the commit that introduced the problem:
c7f404b40a3665d9f4e9a927cc5c1ee0479ed8f9
vfs: new superblock methods to override /proc/*/mount{s,info}

The last commit to be problem free was the previous one:
f8ad9c4bae99854c961ca79ed130a0d11d9ab53c
nfs: nfs_do_{ref,sub}mount() superblock argument is redundant


I think this bug should be fixed before Wheezy becomes stable.

Thanks a lot,
Chris



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Chris Hiestand wrote:

> Based on this tip I tested that commit and neighboring commits and was
> able to find the commit that introduced the problem:
> c7f404b40a3665d9f4e9a927cc5c1ee0479ed8f9
> vfs: new superblock methods to override /proc/*/mount{s,info}

Hmph.

Please send a summary of the symptoms to Alexander Viro
<viro@zeniv.linux.org.uk>, cc-ing linux-nfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, and either me or this bug log so we can
track it. Be sure to mention:

- steps to reproduce the problem, expected result, actual result, and
how the difference indicates a bug
- the date and log message for the commit that introduced the problem
- which kernel versions you have tested and what happens with each
- any other weird symptoms or observations
- a link to <http://bugs.debian.org/669314> for the backstory

Hopefully Al can say whether the change in behavior was intentional
and, either way, what an appropriate way to move forward would be.

Thanks again for your help, and hope that helps.

Sincerely,
Jonathan



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