Date: Thu, 2 Jul 2015 13:01:39 -0400
From: Jeff Layton <jlayton@poochiereds.net>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [git pull] vfs part 2
Message-ID: <20150702130139.35e01106@tlielax.poochiereds.net>
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On Thu, 2 Jul 2015 17:45:35 +0100
Al Viro <viro@ZenIV.linux.org.uk> wrote:

> On Thu, Jul 02, 2015 at 08:07:38AM -0400, Jeff Layton wrote:
> 
> > Erm...and why is it passing in '0' to idr_alloc for the end value if it
> > can't deal with more than 16 bits? That seems like a plain old bug...
> 
> Because they are using the same function (with different pool, obviously)
> for FID allocation, and those are 32bit...

Ahh, right...

So p9_idpool_create should take an argument for the "end" value, and
then store that in a new field in p9_idpool. Then they can pass that in
as the "end" parm in idr_alloc. Or, they could give up using the same
function there and use a different one for tags and FIDs.

In any case...allowing this thing to allocate tag values that can
collide seems fundamentally wrong. Using idr_alloc_cyclic might also
not hurt either, particularly given that these tag values are supposed
to function something like an XID and you probably don't want to be
reusing them too quickly.

-- 
Jeff Layton <jlayton@poochiereds.net>
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