From: Kevin Easton <kevin@guarana.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>, Qian Cai <cai@lca.pw>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: "fs/namei.c: keep track of nd->root refcount status" causes boot panic
Date: Thu, 5 Sep 2019 12:17:55 +0000 [thread overview]
Message-ID: <20190905121755.GA23258@ip-172-31-14-16> (raw)
In-Reply-To: <20190903175610.GM1131@ZenIV.linux.org.uk>
On Tue, Sep 03, 2019 at 06:56:10PM +0100, Al Viro wrote:
> On Tue, Sep 03, 2019 at 08:39:30AM -0700, Christoph Hellwig wrote:
>
> > > There's much nastier situation than "new upstream kernel released,
> > > need to rebuild" - it's bisect in mainline trying to locate something...
> >
> > I really don't get the point. And it's not like we've card about
> > this anywhere else. And jumping wildly around with the numeric values
> > for constants will lead to bugs like the one you added and fixed again
> > and again.
>
> The thing is, there are several groups - it's not as if all additions
> were guaranteed to be at the end. So either we play with renumbering
> again and again, or we are back to the square one...
>
> Is there any common trick that would allow to verify the lack of duplicates
> at the build time?
What about:
static_assert(
(LOOKUP_FOLLOW^LOOKUP_DIRECTORY^LOOKUP_AUTOMOUNT^LOOKUP_EMPTY^LOOKUP_DOWN^
LOOKUP_REVAL^LOOKUP_RCU^
LOOKUP_OPEN^LOOKUP_CREATE^LOOKUP_EXCL^LOOKUP_RENAME_TARGET^
LOOKUP_PARENT^LOOKUP_NO_REVAL^LOOKUP_JUMPED^LOOKUP_ROOT^LOOKUP_ROOT_GRABBED)
==
(LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_AUTOMOUNT|LOOKUP_EMPTY|LOOKUP_DOWN|
LOOKUP_REVAL|LOOKUP_RCU|
LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL|LOOKUP_RENAME_TARGET|
LOOKUP_PARENT|LOOKUP_NO_REVAL|LOOKUP_JUMPED|LOOKUP_ROOT|LOOKUP_ROOT_GRABBED)
, "duplicated LOOKUP_* constant");
?
- Kevin
next prev parent reply other threads:[~2019-09-05 12:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 4:21 "fs/namei.c: keep track of nd->root refcount status" causes boot panic Qian Cai
2019-09-03 5:22 ` Dexuan-Linux Cui
2019-09-03 5:50 ` Dexuan Cui
2019-09-03 6:00 ` Dexuan Cui
2019-09-03 8:13 ` Naresh Kamboju
2019-09-03 9:08 ` Sachin Sant
2019-09-03 12:37 ` Al Viro
2019-09-03 13:04 ` Christoph Hellwig
2019-09-03 13:48 ` Al Viro
2019-09-03 13:50 ` Christoph Hellwig
2019-09-03 13:53 ` Al Viro
2019-09-03 15:39 ` Christoph Hellwig
2019-09-03 17:56 ` Al Viro
2019-09-04 12:39 ` Christoph Hellwig
2019-09-05 9:13 ` Naresh Kamboju
2019-09-05 16:46 ` Al Viro
2019-09-05 12:17 ` Kevin Easton [this message]
2019-09-03 21:30 ` Theodore Y. Ts'o
2019-09-03 13:31 ` Al Viro
2019-09-03 13:52 ` Naresh Kamboju
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