NFS: Simplify the cache invalidation code

Now that NFSv2 and NFSv3 have simulated change attributes,
instead of using all three of mtime, ctime and change attribute to
manage data cache consistency, we can simplify the code to just use
the change attribute.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -958,7 +958,7 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat
 
 	/* Verify a few of the more important attributes */
 	if ((fattr->valid & NFS_ATTR_FATTR_MTIME) && !timespec_equal(&inode->i_mtime, &fattr->mtime))
-		invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
+		invalid |= NFS_INO_INVALID_ATTR;
 
 	if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
 		cur_size = i_size_read(inode);
@@ -1325,38 +1325,15 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 		invalid |= save_cache_validity;
 
 	if (fattr->valid & NFS_ATTR_FATTR_MTIME) {
-		/* NFSv2/v3: Check if the mtime agrees */
-		if (!timespec_equal(&inode->i_mtime, &fattr->mtime)) {
-			dprintk("NFS: mtime change on server for file %s/%ld\n",
-					inode->i_sb->s_id, inode->i_ino);
-			invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
-			if (S_ISDIR(inode->i_mode))
-				nfs_force_lookup_revalidate(inode);
-			memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
-		}
+		memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
 	} else if (server->caps & NFS_CAP_MTIME)
 		invalid |= save_cache_validity & (NFS_INO_INVALID_ATTR
-				| NFS_INO_INVALID_DATA
-				| NFS_INO_REVAL_PAGECACHE
 				| NFS_INO_REVAL_FORCED);
 
 	if (fattr->valid & NFS_ATTR_FATTR_CTIME) {
-		/* If ctime has changed we should definitely clear access+acl caches */
-		if (!timespec_equal(&inode->i_ctime, &fattr->ctime)) {
-			invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
-			/* and probably clear data for a directory too as utimes can cause
-			 * havoc with our cache.
-			 */
-			if (S_ISDIR(inode->i_mode)) {
-				invalid |= NFS_INO_INVALID_DATA;
-				nfs_force_lookup_revalidate(inode);
-			}
-			memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
-		}
+		memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
 	} else if (server->caps & NFS_CAP_CTIME)
 		invalid |= save_cache_validity & (NFS_INO_INVALID_ATTR
-				| NFS_INO_INVALID_ACCESS
-				| NFS_INO_INVALID_ACL
 				| NFS_INO_REVAL_FORCED);
 
 	/* Check if our cached file size is stale */