Re: [PATCH 2.4.19pre8][RFC] remove-NFS-close-to-open from VFS (was Re: [PATCHSET] 2.4.19-pre8-jp12)

[Jan Harkes <jaharkes@cs.cmu.edu>]

On Fri, Oct 18, 2002 at 07:41:40PM +0200, Trond Myklebust wrote:
> >>>>> " " == Jan Harkes <jaharkes@cs.cmu.edu> writes:
> 
>      > So, we're not really revalidating the dcache entry at
>      > all. Maybe the code really wants to revalidate the inode.
> 
> That is indeed the correct thing to do here according to POSIX, and is
> really all I want to do for NFS too.  For that reason, I originally
> proposed to use i_op->revalidate(), but that was vetoed as you may
> recall.

It was? I really hope I wasn't one of the veto-ers because looking at
this problem it does seem like the correct thing to do as we're not
trying to see whether the path is correct, but only the object.

Ok, it will cost Coda a whole upcall/context switch, but as it is '.'
we're talking about it should already be locally cached.

btw. you can easily drop the lookup in nfs_lookup_revalidate.
It is a bug for this case, and not necessary in all other places
d_revalidate is called as the VFS already uses real_lookup in those
cases.

Jan


Haven't tried to compile it yet, but I guess it would look something
like this?

diff -urN linux-2.4.19/fs/namei.c linux-2.4.19-revalidate/fs/namei.c
--- linux-2.4.19/fs/namei.c	2002-08-28 01:07:35.000000000 -0400
+++ linux-2.4.19-revalidate/fs/namei.c	2002-10-18 14:21:13.000000000 -0400
@@ -633,9 +633,12 @@
 		 * Check the cached dentry for staleness.
 		 */
 		dentry = nd->dentry;
-		if (dentry && dentry->d_op && dentry->d_op->d_revalidate) {
+		if (dentry) {
 			err = -ESTALE;
-			if (!dentry->d_op->d_revalidate(dentry, 0)) {
+			if (!dentry->d_inode || is_bad_inode(dentry->d_inode) ||
+			    (dentry->d_inode->i_op && 
+			     dentry->d_inode->i_op->revalidate &&
+			    !dentry->d_inode->i_op->revalidate(dentry))) {
 				d_invalidate(dentry);
 				break;
 			}