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Mount version older than kernel: 4 vs. 6

DISCUSSION Frank Steiner 3 participants 5 messages Aug 4, 2004

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Frank Steiner

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#0 lore raw

Hi,

using kernel 2.6.8rc3 and util-linux-2.12a, I ran into those "mount version older than kernel" messages, which were discussed here for the 2.6.4 kernel before. Patching inode.c, I can see that NFS_MOUNT_VERSION is 6, while data->version is 4. (The only mount at all that does not complain is the one done by nfsroot (of course) :-))

Just a stupid question: why does the nfsmount.h from the kernel source define NFS_MOUNT_VERSION 6? Shouldn't this number match the latest nfs version, i.e., 4? I've never heard of nfs v6 yet :-)
Or is the meaning of NFS_MOUNT_VERSION different?

Would it be safe to patch nfsmount.h and set the number to 4 for my own kernel to get rid of this warning, or could that break sth. else? It just fills my logs and I want to get rid of it...

cu,
Frank

Signature · 15 lines
Dipl.-Inform. Frank Steiner   Web:  http://www.bio.ifi.lmu.de/~steiner/
Lehrstuhl f. Bioinformatik    Mail: http://www.bio.ifi.lmu.de/~steiner/m/
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#1 lore raw
Quoted 4 lines · Frank Steiner

Just a stupid question: why does the nfsmount.h from the kernel source define NFS_MOUNT_VERSION 6? Shouldn't this number match the latest nfs version, i.e., 4? I've never heard of nfs v6 yet :-)
Or is the meaning of NFS_MOUNT_VERSION different?

That's the version of the NFS kernel mount struct, and is absolutely unrelated to the NFS version (except that both grow monotonically over time).

Quoted 3 lines

Would it be safe to patch nfsmount.h and set the number to 4 for my own kernel to get rid of this warning, or could that break sth. else? It just fills my logs and I want to get rid of it...

Our kernel has a patch to silence that warning for versions < 3. But I wouldn't mind if it was nixed entirely.

Olaf

Signature · 3 lines
Olaf Kirch     |  The Hardware Gods hate me.
[email protected]   |
---------------+

Bug #36841: Disable ``mount version is older than kernel'' warning:
The kernel for SL 9.1 will support a higher mount version than the mount binary.

Bug #37689: Some people still saw kernel messages complaining about the mount version. It seems this happens when the first mount attempt using kernel mount version 4 fails for some reason (for instance if the server doesn't support NFSv3) mount falls back to mount version 3.
So we should really warn about versions < 3 only. --okir

fs/nfs/inode.c +3 -2
Index: linux-2.6.4/fs/nfs/inode.c
===================================================================
@@ -1389,8 +1389,9 @@ static struct super_block *nfs_get_sb(st
 		memset(root->data+root->size, 0, sizeof(root->data)-root->size);
 
 	if (data->version != NFS_MOUNT_VERSION) {
-		printk("nfs warning: mount version %s than kernel\n",
-			data->version < NFS_MOUNT_VERSION ? "older" : "newer");
+		if (data->version < 3)
+			printk("nfs warning: mount version %d is older "
+			       "than 3\n", data->version);
 		if (data->version < 2)
 			data->namlen = 0;
 		if (data->version < 3)
author
#2 lore raw
Quoted 11 lines · Olaf Kirch
Quoted 4 lines · Frank Steiner

Just a stupid question: why does the nfsmount.h from the kernel source define NFS_MOUNT_VERSION 6? Shouldn't this number match the latest nfs version, i.e., 4? I've never heard of nfs v6 yet :-)
Or is the meaning of NFS_MOUNT_VERSION different?

That's the version of the NFS kernel mount struct, and is absolutely unrelated to the NFS version (except that both grow monotonically over time).

I see. But then it looks like a bug to me that the code in the inode.c is comparing the "NFS version" (4, in data->version) against the "NFS kernel mount struct" (6, in NFS_MOUNT_VERSION). That doesn't make sense, does it?

I added this to inode.c

        if (data->version != NFS_MOUNT_VERSION) {
                printk("nfs warning: mount version %s than kernel\n",
                        data->version < NFS_MOUNT_VERSION ? "older" : "newer");

+ printk("data version: %d\n",data->version);
+ printk("NFS_MOUNT_VERSION: %d\n",NFS_MOUNT_VERSION);

and got this result:

Aug  4 14:33:50 riemann kernel: nfs warning: mmmount version older than kernel
Aug  4 14:33:50 riemann kernel: data version: 4
Aug  4 14:33:50 riemann kernel: NFS_MOUNT_VERSION: 6

cu,
Frank

Signature · 15 lines
Dipl.-Inform. Frank Steiner   Web:  http://www.bio.ifi.lmu.de/~steiner/
Lehrstuhl f. Bioinformatik    Mail: http://www.bio.ifi.lmu.de/~steiner/m/
LMU, Amalienstr. 17           Phone: +49 89 2180-4049
80333 Muenchen, Germany       Fax:   +49 89 2180-99-4049
* Rekursion kann man erst verstehen, wenn man Rekursion verstanden hat. *


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#3 lore raw
Quoted 4 lines · Frank Steiner

I see. But then it looks like a bug to me that the code in the inode.c is comparing the "NFS version" (4, in data->version) against the "NFS kernel mount struct" (6, in NFS_MOUNT_VERSION). That doesn't make sense, does it?

data->version _is_ the API version. Your mount binary currently uses API version 4. The kernel supports up to API version 6 (which add NFSv4 support).

Olaf

Signature · 13 lines
Olaf Kirch     |  The Hardware Gods hate me.
[email protected]   |
---------------+ 


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#4 lore raw

P=E5 on , 04/08/2004 klokka 06:51, skreiv Olaf Kirch:

Quoted 9 lines · Frank Steiner
Quoted 4 lines

I see. But then it looks like a bug to me that the code in the inode.c is comparing the "NFS version" (4, in data->version) against the "NFS kernel mount struct" (6, in NFS_MOUNT_VERSION). That doesn't make sense, does it?

=20
data->version _is_ the API version. Your mount binary currently uses API version 4. The kernel supports up to API version 6 (which add NFSv4 support).

Nope. NFSv4 uses an entirely separate mount structure.

For the NFSv2/v3 mount structure, API version 5 adds RPCSEC_GSS the secure RPC model. API version 6 adds support for passing security context information down for use by LSM/SELinux/...

Cheers,
Trond

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