---

yaml
---
r: 217087
b: refs/heads/master
c: 6b96724
h: refs/heads/master
i:
  217085: 2e82887
  217083: bad960c
  217079: b924f18
  217071: 95ef4f9
  217055: ac60699
  217023: 72f3656
  216959: e5bc886
  216831: 7516913
  216575: c6c1946
  216063: 66acf48
  215039: 452be46
  212991: 0c478d4
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 118df3d17f11733b294ea2cd988d56ee376ef9fd
+refs/heads/master: 6b96724e507fecc3e6440e86426fe4f44359ed66

trunk/fs/nfs/client.c

@@ -915,6 +915,8 @@ static void nfs_server_set_fsinfo(struct nfs_server *server, struct nfs_fsinfo *
 
 	server->maxfilesize = fsinfo->maxfilesize;
 
+	server->time_delta = fsinfo->time_delta;
+
 	/* We're airborne Set socket buffersize */
 	rpc_setbufsize(server->client, server->wsize + 100, server->rsize + 100);
 }

trunk/fs/nfs/file.c

@@ -757,6 +757,11 @@ do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
 	return status;
 }
 
+static int
+is_time_granular(struct timespec *ts) {
+	return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
+}
+
 static int
 do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
 {
@@ -781,13 +786,21 @@ do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
 		status = do_vfs_lock(filp, fl);
 	if (status < 0)
 		goto out;
+
 	/*
-	 * Make sure we clear the cache whenever we try to get the lock.
+	 * Revalidate the cache if the server has time stamps granular
+	 * enough to detect subsecond changes.  Otherwise, clear the
+	 * cache to prevent missing any changes.
+	 *
 	 * This makes locking act as a cache coherency point.
 	 */
 	nfs_sync_mapping(filp->f_mapping);
-	if (!nfs_have_delegation(inode, FMODE_READ))
-		nfs_zap_caches(inode);
+	if (!nfs_have_delegation(inode, FMODE_READ)) {
+		if (is_time_granular(&NFS_SERVER(inode)->time_delta))
+			__nfs_revalidate_inode(NFS_SERVER(inode), inode);
+		else
+			nfs_zap_caches(inode);
+	}
 out:
 	return status;
 }

trunk/fs/nfs/nfs3xdr.c

@@ -1044,8 +1044,9 @@ nfs3_xdr_fsinfores(struct rpc_rqst *req, __be32 *p, struct nfs_fsinfo *res)
 	res->wtmult = ntohl(*p++);
 	res->dtpref = ntohl(*p++);
 	p = xdr_decode_hyper(p, &res->maxfilesize);
+	p = xdr_decode_time3(p, &res->time_delta);
 
-	/* ignore time_delta and properties */
+	/* ignore properties */
 	res->lease_time = 0;
 	return 0;
 }

trunk/include/linux/nfs_fs_sb.h

@@ -124,6 +124,7 @@ struct nfs_server {
 
 	struct nfs_fsid		fsid;
 	__u64			maxfilesize;	/* maximum file size */
+	struct timespec		time_delta;	/* smallest time granularity */
 	unsigned long		mount_time;	/* when this fs was mounted */
 	dev_t			s_dev;		/* superblock dev numbers */
 

trunk/include/linux/nfs_xdr.h

@@ -112,6 +112,7 @@ struct nfs_fsinfo {
 	__u32			wtmult;	/* writes should be multiple of this */
 	__u32			dtpref;	/* pref. readdir transfer size */
 	__u64			maxfilesize;
+	struct timespec		time_delta; /* server time granularity */
 	__u32			lease_time; /* in seconds */
 };