Date: Thu, 06 Nov 2003 16:02:01 -0800 From: Kirk McKusick <mckusick@beastie.mckusick.com> To: Tim Robbins <tjr@freebsd.org> Cc: Peter Wemm <peter@freebsd.org> Subject: Re: >0x7fffffff blocksize filesystem reporting Message-ID: <200311070002.hA7021eN035691@beastie.mckusick.com> In-Reply-To: Your message of "Thu, 06 Nov 2003 17:45:28 %2B1100." <20031106064528.GA1440@wombat.robbins.dropbear.id.au>
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> Date: Thu, 6 Nov 2003 17:45:28 +1100
> From: Tim Robbins <tjr@freebsd.org>
> To: Kirk McKusick <mckusick@mckusick.com>
> Cc: Peter Wemm <peter@freebsd.org>, Robert Watson <rwatson@nailabs.com>,
> arch@freebsd.org
> Subject: Re: >0x7fffffff blocksize filesystem reporting
> X-ASK-Info: Whitelist match
>
> On Wed, Nov 05, 2003 at 09:04:41PM -0800, Kirk McKusick wrote:
>
> > + /*
> > + * Convert a new format statfs structure to an old format statfs structure.
> > + */
> > + static void
> > + cvtstatfs(td, nsp, osp)
> > + struct thread *td;
> > + struct statfs *nsp;
> > + struct ostatfs *osp;
> > + {
> > +
> > + bzero(osp, sizeof(*osp));
> > + osp->f_bsize = nsp->f_bsize;
> > + osp->f_iosize = nsp->f_iosize;
> > + osp->f_blocks = nsp->f_blocks;
> > + osp->f_bfree = nsp->f_bfree;
> > + osp->f_bavail = nsp->f_bavail;
> > + osp->f_files = nsp->f_files;
> > + osp->f_ffree = nsp->f_ffree;
> > + osp->f_owner = nsp->f_owner;
> > + osp->f_type = nsp->f_type;
> > + osp->f_flags = nsp->f_flags;
> > + osp->f_syncwrites = nsp->f_syncwrites;
> > + osp->f_asyncwrites = nsp->f_asyncwrites;
> > + osp->f_syncreads = nsp->f_syncreads;
> > + osp->f_asyncreads = nsp->f_asyncreads;
>
> It may be better to return LONG_MAX for some of these members than to
> truncate the value. Alternatively, the block size could be adjusted
> to ensure that f_blocks fits in a "long" even though f_blocks * f_bsize
> may overflow it, but this is messy and can't help if f_files or
> f_{sync,async}{reads,writes} are too big.
>
> > + bcopy(nsp->f_fstypename, osp->f_fstypename, MFSNAMELEN);
> > + bcopy(nsp->f_mntonname, osp->f_mntonname, MNAMELEN);
> > + bcopy(nsp->f_mntfromname, osp->f_mntfromname, MNAMELEN);
>
> On architectures where longs are not 32 bits (amd64), OMNAMELEN != MNAMELEN,
> so this may do the wrong thing.
>
>
> Tim
You make two good points. Here is my revised diff for cvtstatfs:
+ /*
+ * Convert a new format statfs structure to an old format statfs structure.
+ */
+ static void
+ cvtstatfs(td, nsp, osp)
+ struct thread *td;
+ struct statfs *nsp;
+ struct ostatfs *osp;
+ {
+
+ bzero(osp, sizeof(*osp));
+ osp->f_bsize = MIN(nsp->f_bsize, LONG_MAX);
+ osp->f_iosize = MIN(nsp->f_iosize, LONG_MAX);
+ osp->f_blocks = MIN(nsp->f_blocks, LONG_MAX);
+ osp->f_bfree = MIN(nsp->f_bfree, LONG_MAX);
+ osp->f_bavail = MIN(nsp->f_bavail, LONG_MAX);
+ osp->f_files = MIN(nsp->f_files, LONG_MAX);
+ osp->f_ffree = MIN(nsp->f_ffree, LONG_MAX);
+ osp->f_owner = nsp->f_owner;
+ osp->f_type = nsp->f_type;
+ osp->f_flags = nsp->f_flags;
+ osp->f_syncwrites = MIN(nsp->f_syncwrites, LONG_MAX);
+ osp->f_asyncwrites = MIN(nsp->f_asyncwrites, LONG_MAX);
+ osp->f_syncreads = MIN(nsp->f_syncreads, LONG_MAX);
+ osp->f_asyncreads = MIN(nsp->f_asyncreads, LONG_MAX);
+ bcopy(nsp->f_fstypename, osp->f_fstypename,
+ MIN(MFSNAMELEN, OMNAMELEN));
+ bcopy(nsp->f_mntonname, osp->f_mntonname,
+ MIN(MFSNAMELEN, OMNAMELEN));
+ bcopy(nsp->f_mntfromname, osp->f_mntfromname,
+ MIN(MFSNAMELEN, OMNAMELEN));
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