NFS: We must use list_for_each_entry_safe in nfs_access_cache_shrinker

We may end up removing the current entry from nfs_access_lru_list.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/dir.c

@@ -1788,14 +1788,14 @@ static void nfs_access_free_list(struct list_head *head)
 int nfs_access_cache_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
 {
 	LIST_HEAD(head);
-	struct nfs_inode *nfsi;
+	struct nfs_inode *nfsi, *next;
 	struct nfs_access_entry *cache;
 
 	if ((gfp_mask & GFP_KERNEL) != GFP_KERNEL)
 		return (nr_to_scan == 0) ? 0 : -1;
 
 	spin_lock(&nfs_access_lru_lock);
-	list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) {
+	list_for_each_entry_safe(nfsi, next, &nfs_access_lru_list, access_cache_inode_lru) {
 		struct inode *inode;
 
 		if (nr_to_scan-- == 0)