NFS: Fix and clean up the access cache validity checking

The access cache needs to check whether or not the mode bits, ownership,
or ACL has changed or the cache has timed out.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/dir.c

@@ -2286,8 +2286,7 @@ static int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, str
 		if (cache == NULL)
 			goto out;
 		/* Found an entry, is our attribute cache valid? */
-		if (!nfs_attribute_cache_expired(inode) &&
-		    !(nfsi->cache_validity & NFS_INO_INVALID_ATTR))
+		if (!nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
 			break;
 		err = -ECHILD;
 		if (!may_block)
@@ -2335,12 +2334,12 @@ static int nfs_access_get_cached_rcu(struct inode *inode, struct rpc_cred *cred,
 		cache = NULL;
 	if (cache == NULL)
 		goto out;
-	err = nfs_revalidate_inode_rcu(NFS_SERVER(inode), inode);
-	if (err)
+	if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS))
 		goto out;
 	res->jiffies = cache->jiffies;
 	res->cred = cache->cred;
 	res->mask = cache->mask;
+	err = 0;
 out:
 	rcu_read_unlock();
 	return err;
@@ -2492,12 +2491,13 @@ EXPORT_SYMBOL_GPL(nfs_may_open);
 static int nfs_execute_ok(struct inode *inode, int mask)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
-	int ret;
+	int ret = 0;
 
-	if (mask & MAY_NOT_BLOCK)
-		ret = nfs_revalidate_inode_rcu(server, inode);
-	else
-		ret = nfs_revalidate_inode(server, inode);
+	if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_ACCESS)) {
+		if (mask & MAY_NOT_BLOCK)
+			return -ECHILD;
+		ret = __nfs_revalidate_inode(server, inode);
+	}
 	if (ret == 0 && !execute_ok(inode))
 		ret = -EACCES;
 	return ret;