NFS: nfs_lookup doesn't need to revalidate the parent directory's inode

 nfs_lookup() used to consult a lookup cache before trying an actual wire
 lookup operation.  The lookup cache would be invalid, of course, if the
 parent directory's mtime had changed, so nfs_lookup performed an inode
 revalidation on the parent.

 Since nfs_lookup() doesn't use a cache anymore, the revalidation is no
 longer necessary.  There are cases where it will generate a lot of
 unnecessary GETATTR traffic.

 See http://bugzilla.linux-nfs.org/show_bug.cgi?id=9

 Test-plan:
 Use lndir and "rm -rf" and watch for excess GETATTR traffic or application
 level errors.

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b8a7304..ce8f77d 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -853,12 +853,6 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
        dentry->d_op = NFS_PROTO(dir)->dentry_ops;
 
        lock_kernel();
-       /* Revalidate parent directory attribute cache */
-       error = nfs_revalidate_inode(NFS_SERVER(dir), dir);
-       if (error < 0) {
-               res = ERR_PTR(error);
-               goto out_unlock;
-       }
 
        /* If we're doing an exclusive create, optimize away the lookup */
        if (nfs_is_exclusive_create(dir, nd))