svn commit: r325386 - head/sys/kern

[Andriy Gapon]

On 05/11/2017 21:02, Konstantin Belousov wrote:
> On Sun, Nov 05, 2017 at 11:42:51AM -0700, Warner Losh wrote:
>> On Sun, Nov 5, 2017 at 11:32 AM, Conrad Meyer <cem at freebsd.org> wrote:
>>
>>> E.g.,
>>>
>>> --- a/sys/ufs/ffs/ffs_alloc.c
>>> +++ b/sys/ufs/ffs/ffs_alloc.c
>>> @@ -304,8 +304,7 @@ retry:
>>>         }
>>>
>>>         if (bp->b_blkno == bp->b_lblkno) {
>>> -               if (lbprev >= UFS_NDADDR)
>>> -                       panic("ffs_realloccg: lbprev out of range");
>>> +               ASSERT(lbprev < UFS_NDADDR, "ffs_realloccg: lbprev out
>>> of range");
>>>                 bp->b_blkno = fsbtodb(fs, bprev);
>>>         }
>>>
>>
>> Just a side point: All these should be programming errors. The bogus data
>> that comes or could come from the FS itself should remain always-on panics.
>> Well, actually, they should transition from always-on panics to some sort
>> of degraded mount that would be more resilient in the face of such
>> corruption. But failing that, they should remain always-on panics :)
> 
> This is what I said in my reply before the last.
> 
> I still have no idea what is the point cem tries to express.
> 
> Nor I know what should the ASSERT() macro do in the kernel. If the
> patch above really about replacing panic() with _K_ASSERT, then I most
> likely agree with it, since the error catched is not due to the on-disk
> metadata corruption.
> 

I guess (only guess) that Conrad is saying that it would be useful to have a
macro like KASSERT but which would be always active regardless of INVARIANTS.
E.g. in illumos they have ASSERT and VERIFY.

-- 
Andriy Gapon