NFS: Fix revalidation of empty readdir pages

If the page is empty, we need to check the array->last_cookie instead of
the first entry. Add a helper for the cases where we care.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 17986c0019d4a2875af44c662dc72a1474493dfd..bac4cf1a308efe8c9ef55b582d8fef9ace5d9430 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -252,6 +252,11 @@ static void nfs_readdir_page_array_free(struct page *page)
        }
 }
 
+static u64 nfs_readdir_array_index_cookie(struct nfs_cache_array *array)
+{
+       return array->size == 0 ? array->last_cookie : array->array[0].cookie;
+}
+
 static void nfs_readdir_array_set_eof(struct nfs_cache_array *array)
 {
        array->page_is_eof = 1;
@@ -369,7 +374,7 @@ static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie,
 
        if (array->change_attr != change_attr)
                ret = false;
-       if (array->size > 0 && array->array[0].cookie != last_cookie)
+       if (nfs_readdir_array_index_cookie(array) != last_cookie)
                ret = false;
        kunmap_atomic(array);
        return ret;
@@ -480,7 +485,7 @@ static void nfs_readdir_seek_next_array(struct nfs_cache_array *array,
                desc->cache_entry_index = 0;
                desc->page_index++;
        } else
-               desc->last_cookie = array->array[0].cookie;
+               desc->last_cookie = nfs_readdir_array_index_cookie(array);
 }
 
 static void nfs_readdir_rewind_search(struct nfs_readdir_descriptor *desc)