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>

1 files changed, 11 insertions, 3 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index db29c7fa9620..062e108fac50 100644
--- 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;