Hi Ted,
On Wed, Jan 01, 2014 at 03:46:50PM -0500, Theodore Ts'o wrote:
> On Wed, Jan 01, 2014 at 09:08:00PM +0200, Baruch Siach wrote:
> > Yes. uClibc does provide posix_fadvise64() when __NR_fadvise64_64 is
> > available.
> >
> > > Maybe the better fix would be to try to use posix_fadvise64 if it is exists,
> > > with posix_fadvise() and the locally defined posix_fadvise() as fallbacks.
> >
> > OK. So you suggest to add another autoconf test for posix_fadvise64 and use
> > that as a fall back before trying direct syscall()?
>
> Yes, I think that's the more general and hence the more correct
> answer. In fact what we have right now is arguably wrong, since on a
> 32-bit platform where off_t is 32-bits, and which defines
> posix_fadvise, we wouldn't correctly handle files that are larger than
> 2GB. So if posix_fadvise64 exists, we should be using in preference
> to posix_fadvise(), even if both are provided by the C library.
>
> Would you mind sending such a revised patch?
Just sent. Thanks for reviewing.
Turns out that this is actually an uClibc bug. There used to be a
posix_fadvise definition for xtensa as a wrapper around the __NR_fadvise64_64
system call. This broke with uClibc commit ee84b8b400 (linux: posix_fadvise:
use new SYSCALL_ALIGN_64BIT). The patch I have sent can be used as a
workaround for now. I'll send a separate patch for uClibc later.
baruch
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