[RFC PATCH V2] mount: Added the -o v4.1 mount option

[RFC PATCH V2] mount: Added the -o v4.1 mount option

[Steve Dickson]

This patch will convert -o v4.1, vers=4.1 or nfsvers=4.1 into
the corresponding "v4,minorversion=1", "vers=4,minorversion=1"
or "nfsvers=4,minorversion=1" options.

Signed-off-by: Steve Dickson <steved@redhat.com>
---
 utils/mount/network.c | 18 ++++++++++++++++--
 utils/mount/nfs.man   | 13 +++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/utils/mount/network.c b/utils/mount/network.c
index e7bd522..36aa03b 100644
--- a/utils/mount/network.c
+++ b/utils/mount/network.c
@@ -94,6 +94,7 @@ static const char *nfs_version_opttbl[] = {
 	"v2",
 	"v3",
 	"v4",
+	"v4.1",
 	"vers",
 	"nfsvers",
 	NULL,
@@ -1244,11 +1245,20 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
 	case 2: /* v4 */
 		*version = 4;
 		return 1;
-	case 3:	/* vers */
+	case 3: /* v4.1 */
+		*version = 4;
+		po_remove_all(options, "v4.1");
+		po_append(options, "v4,minorversion=1");
+		return 1;
+	case 4:	/* vers */
 		switch (po_get_numeric(options, "vers", &tmp)) {
 		case PO_FOUND:
 			if (tmp >= 2 && tmp <= 4) {
 				*version = tmp;
+				if (strcmp(po_get(options, "vers"), "4.1") == 0) {
+					po_remove_all(options, "vers");
+					po_append(options, "vers=4,minorversion=1");
+				}
 				return 1;
 			}
 			return 0;
@@ -1261,11 +1271,15 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
 					progname);
 			return 0;
 		}
-	case 4: /* nfsvers */
+	case 5: /* nfsvers */
 		switch (po_get_numeric(options, "nfsvers", &tmp)) {
 		case PO_FOUND:
 			if (tmp >= 2 && tmp <= 4) {
 				*version = tmp;
+				if (strcmp(po_get(options, "nfsvers"), "4.1") == 0) {
+					po_remove_all(options, "nfsvers");
+					po_append(options, "nfsvers=4,minorversion=1");
+				}
 				return 1;
 			}
 			return 0;
diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man
index c15de98..8d1bb56 100644
--- a/utils/mount/nfs.man
+++ b/utils/mount/nfs.man
@@ -762,6 +762,19 @@ by 'nolock'/'lock' mount option.
 Use these options, along with the options in the first subsection above,
 for NFS version 4 and newer.
 .TP 1.5i
+.BI minorversion= n
+Specifies the protocol minor version number.
+NFSv4 introduces "minor versioning," where NFS protocol enhancements can
+be introduced without bumping the NFS protocol version number.
+.IP
+The minor version can also be be specified using the
+.B vers=
+option.
+For example, specifying
+.B vers=4.1
+is the same as specifying
+.BR vers=4,minorversion=1 .
+.TP 1.5i
 .BI proto= netid
 The
 .I netid
-- 
1.7.11.7

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Myklebust, Trond]

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ClRyb25kLk15a2xlYnVzdEBuZXRhcHAuY29tDQp3d3cubmV0YXBwLmNvbQ0K

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Steve Dickson]

On 19/11/12 10:54, Myklebust, Trond wrote:
> On Mon, 2012-11-19 at 10:43 -0500, Steve Dickson wrote:
>> This patch will convert -o v4.1, vers=4.1 or nfsvers=4.1 into
>> the corresponding "v4,minorversion=1", "vers=4,minorversion=1"
>> or "nfsvers=4,minorversion=1" options.
>>
> 
> NACK.
> 
> If you are going to do this, then please do it only for kernels that
> don't support the "vers=4.1" syntax. i.e. anything older than Linux-3.4.
This is the intention... 

> 
> We want to get rid of minorversion=x, not perpetuate it...
> 
Understood... But that is not option in some worlds... ;-) 

steved.

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Myklebust, Trond]

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Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Steve Dickson]

On 19/11/12 11:02, Myklebust, Trond wrote:
> On Mon, 2012-11-19 at 10:58 -0500, Steve Dickson wrote:
>>
>> On 19/11/12 10:54, Myklebust, Trond wrote:
>>> On Mon, 2012-11-19 at 10:43 -0500, Steve Dickson wrote:
>>>> This patch will convert -o v4.1, vers=4.1 or nfsvers=4.1 into
>>>> the corresponding "v4,minorversion=1", "vers=4,minorversion=1"
>>>> or "nfsvers=4,minorversion=1" options.
>>>>
>>>
>>> NACK.
>>>
>>> If you are going to do this, then please do it only for kernels that
>>> don't support the "vers=4.1" syntax. i.e. anything older than Linux-3.4.
>> This is the intention... 
>>
>>>
>>> We want to get rid of minorversion=x, not perpetuate it...
>>>
>> Understood... But that is not option in some worlds... ;-) 
> 
> Sure it is. The mount program can continue to parse minorversion= after
> it is gone from the kernel and convert it into the vers=4.x syntax.
> 
Basically what I'm doing now, with the exception of not adding
the minorversion=1 options... 

BTW, there is a bug in the -o v4.1 current logic... 

mount -o v4.1 produces both "v4.1,vers=4,..." in the string that given
to the kernel which does not seem right... I would assume just a "v4.1,.."
should be pumped down.. 

steved.

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Myklebust, Trond]

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Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Chuck Lever]

On Nov 19, 2012, at 11:24 AM, "Myklebust, Trond" <Trond.Myklebust@netapp.com> wrote:

> On Mon, 2012-11-19 at 11:14 -0500, Steve Dickson wrote:
>> 
>> On 19/11/12 11:02, Myklebust, Trond wrote:
>>> On Mon, 2012-11-19 at 10:58 -0500, Steve Dickson wrote:
>>>> 
>>>> On 19/11/12 10:54, Myklebust, Trond wrote:
>>>>> On Mon, 2012-11-19 at 10:43 -0500, Steve Dickson wrote:
>>>>>> This patch will convert -o v4.1, vers=4.1 or nfsvers=4.1 into
>>>>>> the corresponding "v4,minorversion=1", "vers=4,minorversion=1"
>>>>>> or "nfsvers=4,minorversion=1" options.
>>>>>> 
>>>>> 
>>>>> NACK.
>>>>> 
>>>>> If you are going to do this, then please do it only for kernels that
>>>>> don't support the "vers=4.1" syntax. i.e. anything older than Linux-3.4.
>>>> This is the intention... 
>>>> 
>>>>> 
>>>>> We want to get rid of minorversion=x, not perpetuate it...
>>>>> 
>>>> Understood... But that is not option in some worlds... ;-) 
>>> 
>>> Sure it is. The mount program can continue to parse minorversion= after
>>> it is gone from the kernel and convert it into the vers=4.x syntax.
>>> 
>> Basically what I'm doing now, with the exception of not adding
>> the minorversion=1 options... 
>> 
>> BTW, there is a bug in the -o v4.1 current logic... 
>> 
>> mount -o v4.1 produces both "v4.1,vers=4,..." in the string that given
>> to the kernel which does not seem right... I would assume just a "v4.1,.."
>> should be pumped down.. 
> 
> Yes. I remember seeing that in the Bakeathon tests... I agree that we
> just need the vers=4.1. The extra 'vers=4' isn't harmful in that the
> kernel won't interpret it as vers=4.0, but it would be nice to get rid
> of it.
> 
> Essentially, the plan is that some time in the future we will want to
> have 'vers=4' be the 'auto-negotiate minor version' syntax, while
> vers=4.x will be the 'use minor version x' syntax.
> Of course, auto-negotiation should be driven by the 'mount' program,
> which will be using the 'vers=4.x' syntax in the mount system call, for
> various values of 'x', until it achieves success.

Interesting.  I assume you want "mount.nfs" to do this to allow some kind of auto-negotiation policy to be specified (say, via the mount command configuration file).

As a design precursor, can you speculate on how the mount command would go about negotiating the minor version?  mount.nfs cannot use protocol versions advertised by rpcbind, for instance, and neither can a simple NULL request identify which minor versions are available on the server.

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Chuck Lever]

On Nov 19, 2012, at 10:43 AM, Steve Dickson <steved@redhat.com> wrote:

> This patch will convert -o v4.1, vers=4.1 or nfsvers=4.1 into
> the corresponding "v4,minorversion=1", "vers=4,minorversion=1"
> or "nfsvers=4,minorversion=1" options.

I had a couple of thoughts about this.

As Trond points out, mount.nfs really should not use option "minorversion=" here, except on kernels that do not support "vers=4.x".  That will add complexity, certainly.

In addition, I think we can expect the need for support for "v4.2" and "v4.0" (perhaps) in the near future, and then subsequently "v4.3" and so on.  Since that is close at hand, we should consider the need to add those as we design this.

Perhaps instead of editing the mount option string directly in nfs_nfs_version(), you might add a "*minorversion" argument to nfs_nfs_version() function and let its callers finish the work, just as is done with "*version" today.  That might also make it easier to add the logic that changes behavior based on kernel version.


> 
> Signed-off-by: Steve Dickson <steved@redhat.com>
> ---
> utils/mount/network.c | 18 ++++++++++++++++--
> utils/mount/nfs.man   | 13 +++++++++++++
> 2 files changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/utils/mount/network.c b/utils/mount/network.c
> index e7bd522..36aa03b 100644
> --- a/utils/mount/network.c
> +++ b/utils/mount/network.c
> @@ -94,6 +94,7 @@ static const char *nfs_version_opttbl[] = {
> 	"v2",
> 	"v3",
> 	"v4",
> +	"v4.1",
> 	"vers",
> 	"nfsvers",
> 	NULL,
> @@ -1244,11 +1245,20 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
> 	case 2: /* v4 */
> 		*version = 4;
> 		return 1;
> -	case 3:	/* vers */
> +	case 3: /* v4.1 */
> +		*version = 4;
> +		po_remove_all(options, "v4.1");
> +		po_append(options, "v4,minorversion=1");
> +		return 1;
> +	case 4:	/* vers */
> 		switch (po_get_numeric(options, "vers", &tmp)) {
> 		case PO_FOUND:
> 			if (tmp >= 2 && tmp <= 4) {
> 				*version = tmp;
> +				if (strcmp(po_get(options, "vers"), "4.1") == 0) {
> +					po_remove_all(options, "vers");
> +					po_append(options, "vers=4,minorversion=1");
> +				}
> 				return 1;
> 			}
> 			return 0;
> @@ -1261,11 +1271,15 @@ nfs_nfs_version(struct mount_options *options, unsigned long *version)
> 					progname);
> 			return 0;
> 		}
> -	case 4: /* nfsvers */
> +	case 5: /* nfsvers */
> 		switch (po_get_numeric(options, "nfsvers", &tmp)) {
> 		case PO_FOUND:
> 			if (tmp >= 2 && tmp <= 4) {
> 				*version = tmp;
> +				if (strcmp(po_get(options, "nfsvers"), "4.1") == 0) {
> +					po_remove_all(options, "nfsvers");
> +					po_append(options, "nfsvers=4,minorversion=1");
> +				}
> 				return 1;
> 			}
> 			return 0;
> diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man
> index c15de98..8d1bb56 100644
> --- a/utils/mount/nfs.man
> +++ b/utils/mount/nfs.man
> @@ -762,6 +762,19 @@ by 'nolock'/'lock' mount option.
> Use these options, along with the options in the first subsection above,
> for NFS version 4 and newer.
> .TP 1.5i
> +.BI minorversion= n
> +Specifies the protocol minor version number.
> +NFSv4 introduces "minor versioning," where NFS protocol enhancements can
> +be introduced without bumping the NFS protocol version number.
> +.IP
> +The minor version can also be be specified using the
> +.B vers=
> +option.
> +For example, specifying
> +.B vers=4.1
> +is the same as specifying
> +.BR vers=4,minorversion=1 .
> +.TP 1.5i
> .BI proto= netid
> The
> .I netid
> -- 
> 1.7.11.7
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Myklebust, Trond]

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Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Chuck Lever]

On Nov 19, 2012, at 1:29 PM, "Myklebust, Trond" <Trond.Myklebust@netapp.com> wrote:

> On Mon, 2012-11-19 at 13:11 -0500, Chuck Lever wrote:
>> On Nov 19, 2012, at 11:24 AM, "Myklebust, Trond" <Trond.Myklebust@netapp.com> wrote:
>> 
>>> On Mon, 2012-11-19 at 11:14 -0500, Steve Dickson wrote:
>>>> 
>>>> On 19/11/12 11:02, Myklebust, Trond wrote:
>>>>> On Mon, 2012-11-19 at 10:58 -0500, Steve Dickson wrote:
>>>>>> 
>>>>>> On 19/11/12 10:54, Myklebust, Trond wrote:
>>>>>>> On Mon, 2012-11-19 at 10:43 -0500, Steve Dickson wrote:
>>>>>>>> This patch will convert -o v4.1, vers=4.1 or nfsvers=4.1 into
>>>>>>>> the corresponding "v4,minorversion=1", "vers=4,minorversion=1"
>>>>>>>> or "nfsvers=4,minorversion=1" options.
>>>>>>>> 
>>>>>>> 
>>>>>>> NACK.
>>>>>>> 
>>>>>>> If you are going to do this, then please do it only for kernels that
>>>>>>> don't support the "vers=4.1" syntax. i.e. anything older than Linux-3.4.
>>>>>> This is the intention... 
>>>>>> 
>>>>>>> 
>>>>>>> We want to get rid of minorversion=x, not perpetuate it...
>>>>>>> 
>>>>>> Understood... But that is not option in some worlds... ;-) 
>>>>> 
>>>>> Sure it is. The mount program can continue to parse minorversion= after
>>>>> it is gone from the kernel and convert it into the vers=4.x syntax.
>>>>> 
>>>> Basically what I'm doing now, with the exception of not adding
>>>> the minorversion=1 options... 
>>>> 
>>>> BTW, there is a bug in the -o v4.1 current logic... 
>>>> 
>>>> mount -o v4.1 produces both "v4.1,vers=4,..." in the string that given
>>>> to the kernel which does not seem right... I would assume just a "v4.1,.."
>>>> should be pumped down.. 
>>> 
>>> Yes. I remember seeing that in the Bakeathon tests... I agree that we
>>> just need the vers=4.1. The extra 'vers=4' isn't harmful in that the
>>> kernel won't interpret it as vers=4.0, but it would be nice to get rid
>>> of it.
>>> 
>>> Essentially, the plan is that some time in the future we will want to
>>> have 'vers=4' be the 'auto-negotiate minor version' syntax, while
>>> vers=4.x will be the 'use minor version x' syntax.
>>> Of course, auto-negotiation should be driven by the 'mount' program,
>>> which will be using the 'vers=4.x' syntax in the mount system call, for
>>> various values of 'x', until it achieves success.
>> 
>> Interesting.  I assume you want "mount.nfs" to do this to allow some kind of auto-negotiation policy to be specified (say, via the mount command configuration file).
> 
> Right. I'd like to be able to set Defaultvers=4.1 in /etc/nfsmount.conf
> and have it work.
> 
>> As a design precursor, can you speculate on how the mount command would go about negotiating the minor version?  mount.nfs cannot use protocol versions advertised by rpcbind, for instance, and neither can a simple NULL request identify which minor versions are available on the server.
> 
> Note that the mount command should in any case not be relying on rpcbind
> to decide whether or not the server supports NFSv4.
> 
> As for minor version negotiation, RFC3530 already tells you how to do
> this: the client has to start with the highest version that it supports,
> and then walk that number down until the server stops replying with
> NFS4ERR_MINOR_VERS_MISMATCH.
> 
> Note that if you want to do this in userland before calling the mount
> syscall, then the spec does allow you to "ping" the NFSv4 server with an
> empty COMPOUND.

I see: not an NFSv4 NULL, but an NFSv4 COMPOUND that has no operations.  That carries a compound header, which would have the minor version number in it.

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Myklebust, Trond]

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Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[J. Bruce Fields]

On Mon, Nov 19, 2012 at 07:04:10PM +0000, Myklebust, Trond wrote:
> On Mon, 2012-11-19 at 13:39 -0500, Chuck Lever wrote:
> > On Nov 19, 2012, at 1:29 PM, "Myklebust, Trond" <Trond.Myklebust@netapp.com> wrote:
> > > As for minor version negotiation, RFC3530 already tells you how to do
> > > this: the client has to start with the highest version that it supports,
> > > and then walk that number down until the server stops replying with
> > > NFS4ERR_MINOR_VERS_MISMATCH.
> > > 
> > > Note that if you want to do this in userland before calling the mount
> > > syscall, then the spec does allow you to "ping" the NFSv4 server with an
> > > empty COMPOUND.
> > 
> > I see: not an NFSv4 NULL, but an NFSv4 COMPOUND that has no operations.  That carries a compound header, which would have the minor version number in it.
> 
> Right. Section 16.2.4 of RFC5661 would appear to allow the server to
> return the following errors in the case of an empty COMPOUND: NFS4_OK,
> NFS4ERR_DELAY, NFS4ERR_MINOR_VERS_MISMATCH and NFS4ERR_SERVERFAULT.
> 
> The other errors shouldn't apply at all to a zero-op compound
> (NFS4ERR_BADXDR, NFS4ERR_TOO_MANY_OPS, NFS4ERR_REP_TOO_BIG_TO_CACHE), or
> should only apply if you have a non-empty optional tag argument
> (NFS4ERR_BADCHAR, NFS4ERR_INVAL, NFS4ERR_REP_TOO_BIG,
> NFS4ERR_REQ_TOO_BIG).

And, I just wanted to check because I hadn't thought about this before:
the Linux server does appear to handle 0-length compounds correctly.
(And there's a 4.0 pynfs test, COMP1, which checks that a server will
accept a zero-length compound, so anyone that's run pynfs should have
noticed if there server doesn't.)

--b.

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Steve Dickson]

On 19/11/12 13:29, Myklebust, Trond wrote:
> Note that the mount command should in any case not be relying on rpcbind
> to decide whether or not the server supports NFSv4.
Of course.... 

> 
> As for minor version negotiation, RFC3530 already tells you how to do
> this: the client has to start with the highest version that it supports,
> and then walk that number down until the server stops replying with
> NFS4ERR_MINOR_VERS_MISMATCH.
Perfect... I think we should do *all* v4 negotiation from the mount 
command... It's so much acceptable to replace mount.nfs binaries 
than kernels... 

> 
> Note that if you want to do this in userland before calling the mount
> syscall, then the spec does allow you to "ping" the NFSv4 server with an
> empty COMPOUND.
The type of functionality will allow us to better deal with legacy servers, IMHO..

steved.

Re: [RFC PATCH V2] mount: Added the -o v4.1 mount option

[Steve Dickson]

On 19/11/12 13:21, Chuck Lever wrote:
> 
> As Trond points out, mount.nfs really should not use option "minorversion=" here, except on kernels that do not support "vers=4.x".  That will add complexity, certainly.
I agree... The patch I put out today was just an RFC... I just wanted to get the conversation started... 

> 
> In addition, I think we can expect the need for support for "v4.2" and "v4.0" (perhaps) in the near future, and then subsequently "v4.3" and so on.  Since that is close at hand, we should consider the need to add those as we design this.
Right, I thinking bring this type of negotiation back up to userland is the right thing to do... 

> 
> Perhaps instead of editing the mount option string directly in nfs_nfs_version(), you might add a "*minorversion" argument to nfs_nfs_version() function and let its callers finish the work, just as is done with "*version" today.  That might also make it easier to add the logic that changes behavior based on kernel version.
Let me digest this... I've noticed that in recent kernels that minorversion always seems to be set... 

steved.