NFS suport block sharing

[Olaf Kirch <okir@suse.de>]

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Hi,

yesterday, I ran into something that puzzled me quite a bit.  I had an
NFS file system (my home directory) mounted in its normal location. For
testing purposes, I wanted to mount it a second time, but with a different
set of options (hard instead of soft, etc).

To my surprise, the second mount continued to act like the original
mount, as if it had been mounted with -o soft. /etc/mtab showed the
options I had specified, but /proc/mounts showed that it indeed used
soft retransmits.

To make a long story short, I think _if_ we do NFS super block
sharing, we should make sure we use don't reuse an existing
sb if it has different options. Attached is a patch that implements
this, at least for the most common set of options.

Comments?

Olaf
-- 
Olaf Kirch     |  Stop wasting entropy - start using predictable
okir@suse.de   |  tempfile names today!
---------------+ 

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--- inode.c-reuse	2004-02-17 16:58:25.000000000 +0100
+++ inode.c	2004-02-17 17:00:01.000000000 +0100
@@ -1320,6 +1320,14 @@
 		return 0;
 	if (old->addr.sin_port != server->addr.sin_port)
 		return 0;
+	if (old->flags != server->flags
+	 || old->rsize != server->rsize
+	 || old->wsize != server->wsize
+	 || old->acregmin != server->acregmin
+	 || old->acregmax != server->acregmax
+	 || old->acdirmin != server->acdirmin
+	 || old->acdirmax != server->acdirmax)
+	 	return 0;
 	return !memcmp(&old->fh, &server->fh, sizeof(struct nfs_fh));
 }