Re: Stale NFS handles on 2.4.2

[Trond Myklebust]

>>>>> " " == David Fries <[e-mail]> writes:

     > If I didn't make it clear /home/david directory is the stale
     > NFS filehandle and server:/home is mounted on /home so it isn't
     > the root directory inode here that is having the problem.

Ah. Sorry... Neil's argumentation made me think it might be the root
inode that was stale. Indeed from the code that is currently a
pathology.

Hmm: it looks like the dentry revalidation code is in any case not
complete. Basically it doesn't check if the NFS_INO_STALE flag is set
when deciding whether or not a cached dentry is valid.

OK. We need the patch I sent last night plus a 1-liner in
nfs_inode_is_stale(). That should cover both pathologies. It'll
probably clean up the other cases in which people have been reporting
-ESTALE errors.

Cheers,
   Trond

--- linux-2.4.2/fs/nfs/inode.c.orig	Wed Feb 14 01:14:28 2001
+++ linux-2.4.2/fs/nfs/inode.c	Thu Mar  1 10:00:15 2001
@@ -632,7 +632,7 @@
 	if ((fattr->mode & S_IFMT) != (inode->i_mode & S_IFMT))
 		return 1;
 
-	if (is_bad_inode(inode))
+	if (is_bad_inode(inode) || NFS_STALE(inode))
 		return 1;
 
 	/* Has the filehandle changed? If so is the old one stale? */
@@ -819,24 +819,22 @@
 int
 __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 {
-	int		 status = 0;
+	int		 status = -ESTALE;
 	struct nfs_fattr fattr;
 
 	dfprintk(PAGECACHE, "NFS: revalidating (%x/%Ld)\n",
 		inode->i_dev, (long long)NFS_FILEID(inode));
 
 	lock_kernel();
-	if (!inode || is_bad_inode(inode) || NFS_STALE(inode)) {
-		unlock_kernel();
-		return -ESTALE;
-	}
+	if (!inode || is_bad_inode(inode))
+ 		goto out_nowait;
+	if (NFS_STALE(inode) && inode != inode->i_sb->s_root->d_inode)
+ 		goto out_nowait;
 
 	while (NFS_REVALIDATING(inode)) {
 		status = nfs_wait_on_inode(inode, NFS_INO_REVALIDATING);
-		if (status < 0) {
-			unlock_kernel();
-			return status;
-		}
+		if (status < 0)
+			goto out_nowait;
 		if (time_before(jiffies,NFS_READTIME(inode)+NFS_ATTRTIMEO(inode))) {
 			status = NFS_STALE(inode) ? -ESTALE : 0;
 			goto out_nowait;
@@ -850,7 +848,8 @@
 			 inode->i_dev, (long long)NFS_FILEID(inode), status);
 		if (status == -ESTALE) {
 			NFS_FLAGS(inode) |= NFS_INO_STALE;
-			remove_inode_hash(inode);
+			if (inode != inode->i_sb->s_root->d_inode)
+				remove_inode_hash(inode);
 		}
 		goto out;
 	}
@@ -863,6 +862,8 @@
 	}
 	dfprintk(PAGECACHE, "NFS: (%x/%Ld) revalidation complete\n",
 		inode->i_dev, (long long)NFS_FILEID(inode));
+
+	NFS_FLAGS(inode) &= ~NFS_INO_STALE;
 out:
 	NFS_FLAGS(inode) &= ~NFS_INO_REVALIDATING;
 	wake_up(&inode->i_wait);