Re: [PATCH] fs: change sys_truncate/sys_ftruncate length parametertype

From: Linus Torvalds
Date: Wed Sep 23 2009 - 11:14:36 EST




On Wed, 23 Sep 2009, Heiko Carstens wrote:
>
> For both system calls user space passes a signed long length parameter,
> while the kernel side takes an unsigned long parameter and converts it
> later to signed long again.

No it doesn't.

Look at sys_ftruncate() again. It doesn't convert it to signed long at
all. It converts it to 'loff_t' which is something different entirely.

Now, it may be that we _should_ convert it to 'long' like your patch does,
but this is definitely not a "no changes" patch as far as I can tell. It
limits ftruncate to 31 bits on 32-bit architectures, in ways it didn't use
to be limited.

[ Note the "small" logic and the interaction with O_LARGEFILE. On a 32-bit
architecture, if you open with O_LARGEFILE, ftruncate() gets the full
32-bit range, and that's the part your patch broke. ]

So NAK. Not without some serious explanations on why I'm wrong and am just
being unnecessarily difficult and a pinhead.

Linus
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