Date: Mon, 21 Jan 2002 00:17:49 +0600 From: Max Khon <fjoe@iclub.nsu.ru> To: Bruce Evans <bde@zeta.org.au> Cc: Cy Schubert - ITSD Open Systems Group <Cy.Schubert@uumail.gov.bc.ca>, Poul-Henning Kamp <phk@critter.freebsd.dk>, arch@freebsd.org Subject: Re: request for review Message-ID: <20020121001749.A80939@iclub.nsu.ru> In-Reply-To: <20020116155828.T487-100000@gamplex.bde.org>; from bde@zeta.org.au on Wed, Jan 16, 2002 at 04:18:12PM %2B1100 References: <20020116000607.B10938@iclub.nsu.ru> <20020116155828.T487-100000@gamplex.bde.org>
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hi, there!
On Wed, Jan 16, 2002 at 04:18:12PM +1100, Bruce Evans wrote:
> > > This patch also makes FreeBSD almost compatible with FreeBSD (versions
> > > 1, 2, 3) that is. Old versions vn_stat() simply passed back the
> > > va_blocksize set by VOP_GETTATTR().
> >
> > NetBSD/OpenBSD do exactly the same
>
> The main point of the differences in FreeBSD is to set st_blksize to
> a reasonable value for disks (since individual filesystems didn't do
> it). The changes really shouldn't have affected non-disks.
>
> > > > > I think it is bogus for devices other than disks to flout a
> > > > > va_blocksize, but I am on the other hand not sure what the
> > > > > relevant (if any) standards say.
> > >
> > > POSIX says almost the same as the quote from www.opengroup.org in the
> > > sources: "A file system-specific [sic] preferred I/O block size for
> > > this object". 0 is wrong except possibly for /dev/null since it is
> > > a very bad I/O size.
> >
> > do you think we should remove setting sb->st_blksize to 0 in vn_stat() at all?
>
> Yes. We should also fix any filesystems that set va_blocksize to 0, or
> convert a va_blocksize of 0 to a more sensible st_blksize. I just noticed
> the following comment in vn_stat():
>
> * Default to zero to catch bogus uses of this field.
>
> This causes many bogus block sizes in the same way that a fixed default
> in the kernel does. An st_blksize of 0 means stdio's BUFSIZ in many
> cases, since stdio prefers to use st_blksize but has to invent a block
> size if st_blksize is not useful. BUFSIZ is 1024, which is rather
> small these days. It's good for slow cdevs but not much else.
ok, what do you think about this patch?
Index: vfs_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/vfs_vnops.c,v
retrieving revision 1.126
diff -u -p -r1.126 vfs_vnops.c
--- vfs_vnops.c 13 Jan 2002 11:58:03 -0000 1.126
+++ vfs_vnops.c 20 Jan 2002 17:45:38 -0000
@@ -571,17 +571,17 @@ vn_stat(vp, sb, td)
* Default to zero to catch bogus uses of this field.
*/
- if (vap->va_type == VREG) {
- sb->st_blksize = vap->va_blocksize;
- } else if (vn_isdisk(vp, NULL)) {
+ if (vn_isdisk(vp, NULL)) {
sb->st_blksize = vp->v_rdev->si_bsize_best;
if (sb->st_blksize < vp->v_rdev->si_bsize_phys)
sb->st_blksize = vp->v_rdev->si_bsize_phys;
if (sb->st_blksize < BLKDEV_IOSIZE)
sb->st_blksize = BLKDEV_IOSIZE;
- } else {
- sb->st_blksize = 0;
- }
+ } else
+ sb->st_blksize = vap->va_blocksize;
+
+ if (sb->st_blksize == 0)
+ sb->st_blksize = PAGE_SIZE;
sb->st_flags = vap->va_flags;
if (suser_xxx(td->td_proc->p_ucred, 0, 0))
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