4.1GB limit with nfs3, 2.6 & knfsd?

4.1GB limit with nfs3, 2.6 & knfsd?

[Mike Fedyk]

Hi,

I was trying to tar and bzip2 some directories over the weekend and I think
I may have found a bug.

The operation would consistantly fail when the bzip2ed tar file hit 4.1GB
when directed at a 2.6.1-bk2-nfs-stale-file-handles knfsd server from
another computer running the same kernel.

If I try the operation against a local filesystem, or a 2.4.24 knfsd server
on the network there are no failures and the file is at 18GB and growing on
the local filesystem (not enough space on the 2.4 server...).

This is all from the same nfs client computer.

I plan on doing some more tests with dd and cat against the server after the
files have finished compressing.

Anyone have any ideas?  I know this could be userspace, but why does it work
against a 2.4 knfsd and on the local filesystem?

Re: 4.1GB limit with nfs3, 2.6 & knfsd?

[Andrew Morton]

Mike Fedyk <mfedyk@matchmail.com> wrote:
>
> Hi,
> 
> I was trying to tar and bzip2 some directories over the weekend and I think
> I may have found a bug.
> 
> The operation would consistantly fail when the bzip2ed tar file hit 4.1GB
> when directed at a 2.6.1-bk2-nfs-stale-file-handles knfsd server from
> another computer running the same kernel.
> 
> If I try the operation against a local filesystem, or a 2.4.24 knfsd server
> on the network there are no failures and the file is at 18GB and growing on
> the local filesystem (not enough space on the 2.4 server...).
> 
> This is all from the same nfs client computer.
> 
> I plan on doing some more tests with dd and cat against the server after the
> files have finished compressing.
> 
> Anyone have any ideas?  I know this could be userspace, but why does it work
> against a 2.4 knfsd and on the local filesystem?

Yes, something funny does seem to be happening.

I have a simple NFS mount of an ext2 filesystem via localhost and a 6GB
`dd' fails after 4G:

vmm:/mnt/localhost> strace dd if=/dev/zero of=foo bs=1M count=6000
...
write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = -1 EINVAL (Invalid argument)

vmm:/mnt/localhost> ls -l foo                                     
-rw-r--r--    1 akpm     akpm     4296015872 Feb  9 21:36 foo

But after that, one can continue to grow the file:

vmm:/mnt/localhost> cat /dev/zero >> foo
^C
vmm:/mnt/localhost> ls -l foo           
-rw-r--r--    1 akpm     akpm     4573638656 Feb  9 21:48 foo

Maybe Neil can shed some light?

Re: 4.1GB limit with nfs3, 2.6 & knfsd?

[Neil Brown]

On Monday February 9, akpm@osdl.org wrote:
> Mike Fedyk <mfedyk@matchmail.com> wrote:
> >
> > Hi,
> > 
> > I was trying to tar and bzip2 some directories over the weekend and I think
> > I may have found a bug.
> > 
> > The operation would consistantly fail when the bzip2ed tar file hit 4.1GB
> > when directed at a 2.6.1-bk2-nfs-stale-file-handles knfsd server from
> > another computer running the same kernel.
> > 
> > If I try the operation against a local filesystem, or a 2.4.24 knfsd server
> > on the network there are no failures and the file is at 18GB and growing on
> > the local filesystem (not enough space on the 2.4 server...).
> > 
> > This is all from the same nfs client computer.
> > 
> > I plan on doing some more tests with dd and cat against the server after the
> > files have finished compressing.
> > 
> > Anyone have any ideas?  I know this could be userspace, but why does it work
> > against a 2.4 knfsd and on the local filesystem?
> 
> Yes, something funny does seem to be happening.
> 
> I have a simple NFS mount of an ext2 filesystem via localhost and a 6GB
> `dd' fails after 4G:
> 
> vmm:/mnt/localhost> strace dd if=/dev/zero of=foo bs=1M count=6000
> ...
> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = -1 EINVAL (Invalid argument)
> 

This is probably fixed by the following patch that is sitting in my
queue.
While 2.4 technically needs the same patch, it isn't affected because
it completely ignores the "offset", rather than almost-completely
ignoring it.

NeilBrown

-------------------------------------------------------
off_t in nfsd_commit needs to be loff_t

From: Miquel van Smoorenburg <miquels@cistron.nl>

While I was stress-testing NFS/XFS on 2.6.1/2.6.2-rc, I found that
sometimes my "dd" would exit with:

	#  dd if=/dev/zero bs=4096 > /mnt/file
	dd: writing `standard output': Invalid argument
	1100753+0 records in
	1100752+0 records out

After adding some debug printk's to the server and client code
and some tcpdump-ing, I found that the NFSERR_INVAL was returned by
nfsd_commit on the server.

Turns out that the "offset" argument is off_t instead of loff_t.
It isn't used at all (unfortunately), but it _is_ checked for
sanity, so that's where the error came from.

 ----------- Diffstat output ------------
 ./fs/nfsd/nfs3proc.c        |    4 ++--
 ./fs/nfsd/vfs.c             |    2 +-
 ./include/linux/nfsd/nfsd.h |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff ./fs/nfsd/nfs3proc.c~current~ ./fs/nfsd/nfs3proc.c
--- ./fs/nfsd/nfs3proc.c~current~	2004-02-06 13:38:28.000000000 +1100
+++ ./fs/nfsd/nfs3proc.c	2004-02-06 13:38:28.000000000 +1100
@@ -595,10 +595,10 @@ nfsd3_proc_commit(struct svc_rqst * rqst
 {
 	int	nfserr;
 
-	dprintk("nfsd: COMMIT(3)   %s %d@%ld\n",
+	dprintk("nfsd: COMMIT(3)   %s %u@%Lu\n",
 				SVCFH_fmt(&argp->fh),
 				argp->count,
-				(unsigned long) argp->offset);
+				(unsigned long long) argp->offset);
 
 	if (argp->offset > NFS_OFFSET_MAX)
 		RETURN_STATUS(nfserr_inval);

diff ./fs/nfsd/vfs.c~current~ ./fs/nfsd/vfs.c
--- ./fs/nfsd/vfs.c~current~	2004-02-06 13:38:21.000000000 +1100
+++ ./fs/nfsd/vfs.c	2004-02-06 13:38:28.000000000 +1100
@@ -823,7 +823,7 @@ out:
  */
 int
 nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
-               off_t offset, unsigned long count)
+               loff_t offset, unsigned long count)
 {
 	struct file	file;
 	int		err;

diff ./include/linux/nfsd/nfsd.h~current~ ./include/linux/nfsd/nfsd.h
--- ./include/linux/nfsd/nfsd.h~current~	2004-02-06 13:38:24.000000000 +1100
+++ ./include/linux/nfsd/nfsd.h	2004-02-06 13:38:28.000000000 +1100
@@ -86,7 +86,7 @@ int		nfsd_create_v3(struct svc_rqst *, s
 				struct svc_fh *res, int createmode,
 				u32 *verifier, int *truncp);
 int		nfsd_commit(struct svc_rqst *, struct svc_fh *,
-				off_t, unsigned long);
+				loff_t, unsigned long);
 #endif /* CONFIG_NFSD_V3 */
 int		nfsd_open(struct svc_rqst *, struct svc_fh *, int,
 				int, struct file *);

Re: 4.1GB limit with nfs3, 2.6 & knfsd?

[Mike Fedyk]

On Tue, Feb 10, 2004 at 04:53:56PM +1100, Neil Brown wrote:
> On Monday February 9, akpm@osdl.org wrote:
> > Mike Fedyk <mfedyk@matchmail.com> wrote:
> > >
> > > Hi,
> > > 
> > > I was trying to tar and bzip2 some directories over the weekend and I think
> > > I may have found a bug.
> > > 
> > > The operation would consistantly fail when the bzip2ed tar file hit 4.1GB
> > > when directed at a 2.6.1-bk2-nfs-stale-file-handles knfsd server from
> > > another computer running the same kernel.
> > > 
> > > If I try the operation against a local filesystem, or a 2.4.24 knfsd server
> > > on the network there are no failures and the file is at 18GB and growing on
> > > the local filesystem (not enough space on the 2.4 server...).
> > > 
> > > This is all from the same nfs client computer.
> > > 
> > > I plan on doing some more tests with dd and cat against the server after the
> > > files have finished compressing.
> > > 
> > > Anyone have any ideas?  I know this could be userspace, but why does it work
> > > against a 2.4 knfsd and on the local filesystem?
> > 
> > Yes, something funny does seem to be happening.
> > 
> > I have a simple NFS mount of an ext2 filesystem via localhost and a 6GB
> > `dd' fails after 4G:
> > 
> > vmm:/mnt/localhost> strace dd if=/dev/zero of=foo bs=1M count=6000
> > ...
> > write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> > read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> > write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> > read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576
> > write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = -1 EINVAL (Invalid argument)
> > 
> 
> This is probably fixed by the following patch that is sitting in my
> queue.
> While 2.4 technically needs the same patch, it isn't affected because
> it completely ignores the "offset", rather than almost-completely
> ignoring it.
> 
> NeilBrown

Would this patch work with 2.6.1-bk2-nfs-stale-file-handles, or does it
depend on any other patches?

Re: 4.1GB limit with nfs3, 2.6 & knfsd?

[Neil Brown]

On Monday February 9, mfedyk@matchmail.com wrote:
> > 
> > This is probably fixed by the following patch that is sitting in my
> > queue.
....
> 
> Would this patch work with 2.6.1-bk2-nfs-stale-file-handles, or does it
> depend on any other patches?

It doesn't depend on, or conflict with, any other patches (to my
knowledge).

NeilBrown

Re: 4.1GB limit with nfs3, 2.6 & knfsd?

[Andrew Morton]

Neil Brown <neilb@cse.unsw.edu.au> wrote:
>
> > write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = -1 EINVAL (Invalid argument)
>  > 
> 
>  This is probably fixed by the following patch that is sitting in my
>  queue.

Indeed it is, thanks.