freebsd stable - Sep 2016 - Regression with revision 303970 (was kern.proc.pathname failure while booting from zfs)

On 27/08/2016 22:09, Frederic Chardon wrote:
>> Anybody is able to reproduce this behavior or is it a local problem?
> Reverting 303970 solves this issue. gcore and adb works again, and I
> can start the vboxnet service.
> I recreated my boot pool with no properties defined, just to be sure.
I can not reproduce this issue here.
Unfortunately, I have no clue how kern.proc.pathname works, so I would
appreciate any hints at what filesystem operations I should look for potential
problems.

-- 
Andriy Gapon

On 04/09/2016 11:24, Andriy Gapon wrote:
> On 27/08/2016 22:09, Frederic Chardon wrote:
>>> Anybody is able to reproduce this behavior or is it a local
problem?
>> Reverting 303970 solves this issue. gcore and adb works again, and I
>> can start the vboxnet service.
>> I recreated my boot pool with no properties defined, just to be sure.
> 
> I can not reproduce this issue here.
I was not trying hard enough.  I've just reproduced the problem using a
non-default normalization property.  The issue is that 303970 disabled the use
of VFS name cache when any name "mangling" (normalization,
case-insensitivity)
is enabled.  And apparently I misunderstood how vop_stdvptocnp() works.  So,
right now zfs_vptocnp() is broken when its argument is a non-directory vnode.
That fact is masked when the name cache is used and is exposed otherwise.

I will think about a fix.  Could you please file a bug report for this (if not
already)?
Sorry about the breakage.

-- 
Andriy Gapon