Date: Sun, 5 Nov 2017 21:13:21 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com>, Warner Losh <imp@bsdimp.com> Cc: "Conrad E. Meyer" <cem@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r325386 - head/sys/kern Message-ID: <20f694b3-c60c-1b6d-76a1-2ef14cbdd698@FreeBSD.org> In-Reply-To: <20171105190214.GG2566@kib.kiev.ua> References: <201711041049.vA4AnZUE096709@repo.freebsd.org> <CAG6CVpUaXSX26Bc839kn96EXnUjtGyQ3_eNJPhsRB%2Bv6G6gH1Q@mail.gmail.com> <20171105130607.GA2566@kib.kiev.ua> <CAG6CVpV3SfV8VuNeMJEuN%2BMSu3424mK=HO_-YW9vRt9HEdcJZQ@mail.gmail.com> <20171105173032.GE2566@kib.kiev.ua> <CAG6CVpVQ4RSgz883ezsdExVDQ4RbSiR_y%2BZ5XWDNFeYBpMS-cQ@mail.gmail.com> <CANCZdfqApxd99G-HqVfe4x8EysYJVCAcHksqTeUuBAaYR1OjEA@mail.gmail.com> <20171105190214.GG2566@kib.kiev.ua>
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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@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
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