Re: [PATCH] diskquota: 32bit quota tools on 64bit architectures

From: Andi Kleen
Date: Thu Oct 19 2006 - 12:10:29 EST


Vasily Tarasov <vtaras@xxxxxxxxxx> writes:

> OpenVZ Linux kernel team has discovered the problem
> with 32bit quota tools working on 64bit architectures.
> In 2.6.10 kernel sys32_quotactl() function was replaced by sys_quotactl() with
> the comment "sys_quotactl seems to be 32/64bit clean, enable it for 32bit"
> However this isn't right. Look at if_dqblk structure:
>
> struct if_dqblk {
> __u64 dqb_bhardlimit;
> __u64 dqb_bsoftlimit;
> __u64 dqb_curspace;
> __u64 dqb_ihardlimit;
> __u64 dqb_isoftlimit;
> __u64 dqb_curinodes;
> __u64 dqb_btime;
> __u64 dqb_itime;
> __u32 dqb_valid;
> };
>
> For 32 bit quota tools sizeof(if_dqblk) == 0x44.
> But for 64 bit kernel its size is 0x48, 'cause of alignment!
> Thus we got a problem.
> Attached patch reintroduce sys32_quotactl() function,
> that handles the situation.

Thanks. But the code should be probably common somewhere in fs/*, not
duplicated.

-Andi
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