NFS: Also use readdir info to revalidate positive dentries

If the fileid of the cached dentry fails to match that returned by
the readdir call, then we should also d_drop. Try to take into account the
fact that on NFSv4, readdir may return the "mounted_on_fileid" by looking
for submounts.

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

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index db29c7fa962062b3ae87c216ffcf3f26b53c5ec2..062e108fac50b40834dd6b842e1b7426a98842ef 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1124,9 +1124,16 @@ static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
        name.hash = full_name_hash(name.name, name.len);
        dentry = d_lookup(parent, &name);
        if (dentry != NULL) {
-               /* Is this a positive dentry? */
-               if (dentry->d_inode != NULL)
-                       return dentry;
+               /* Is this a positive dentry that matches the readdir info? */
+               if (dentry->d_inode != NULL &&
+                               (NFS_FILEID(dentry->d_inode) == entry->ino ||
+                               d_mountpoint(dentry))) {
+                       if (!desc->plus || entry->fh->size == 0)
+                               return dentry;
+                       if (nfs_compare_fh(NFS_FH(dentry->d_inode),
+                                               entry->fh) == 0)
+                               goto out_renew;
+               }
                /* No, so d_drop to allow one to be created */
                d_drop(dentry);
                dput(dentry);
@@ -1152,6 +1159,7 @@ static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
                dentry = alias;
        }
 
+out_renew:
        nfs_renew_times(dentry);
        nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
        return dentry;