NFS: Don't force a dcache revalidation if nfs_wcc_update_inode succeeds

The reason is that if the weak cache consistency update was successful,
then we know that our client must be the only one that changed the
directory, and we've already updated the dcache to reflect the change.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -791,24 +791,18 @@ void nfs_end_data_update(struct inode *inode)
 static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 {
 	struct nfs_inode *nfsi = NFS_I(inode);
-	unsigned long now = jiffies;
 
 	/* If we have atomic WCC data, we may update some attributes */
 	if ((fattr->valid & NFS_ATTR_WCC) != 0) {
-		if (timespec_equal(&inode->i_ctime, &fattr->pre_ctime)) {
+		if (timespec_equal(&inode->i_ctime, &fattr->pre_ctime))
 			memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
-			nfsi->cache_change_attribute = now;
-		}
 		if (timespec_equal(&inode->i_mtime, &fattr->pre_mtime)) {
 			memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
 			if (S_ISDIR(inode->i_mode))
 				nfsi->cache_validity |= NFS_INO_INVALID_DATA;
-			nfsi->cache_change_attribute = now;
 		}
-		if (inode->i_size == fattr->pre_size && nfsi->npages == 0) {
+		if (inode->i_size == fattr->pre_size && nfsi->npages == 0)
 			inode->i_size = fattr->size;
-			nfsi->cache_change_attribute = now;
-		}
 	}
 }
 
@@ -919,6 +913,7 @@ int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 	if (unlikely((fattr->valid & NFS_ATTR_FATTR) == 0)) {
 		spin_lock(&inode->i_lock);
 		nfsi->cache_validity |= NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
+		nfsi->cache_change_attribute = jiffies;
 		spin_unlock(&inode->i_lock);
 		goto out;
 	}

fs/nfs/nfs4proc.c

@@ -208,9 +208,12 @@ static void update_changeattr(struct inode *dir, struct nfs4_change_info *cinfo)
 	struct nfs_inode *nfsi = NFS_I(dir);
 
 	spin_lock(&dir->i_lock);
-	nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA;
-	if (cinfo->before == nfsi->change_attr && cinfo->atomic)
+	if (cinfo->after != nfsi->change_attr) {
+		nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA;
+		if (!cinfo->atomic || cinfo->before != nfsi->change_attr)
+			nfsi->cache_change_attribute = jiffies;
 		nfsi->change_attr = cinfo->after;
+	}
 	spin_unlock(&dir->i_lock);
 }
 

include/linux/nfs_fs.h

@@ -235,8 +235,10 @@ static inline void nfs_mark_for_revalidate(struct inode *inode)
 
 	spin_lock(&inode->i_lock);
 	nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS;
-	if (S_ISDIR(inode->i_mode))
+	if (S_ISDIR(inode->i_mode)) {
 		nfsi->cache_validity |= NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA;
+		nfsi->cache_change_attribute = jiffies;
+	}
 	spin_unlock(&inode->i_lock);
 }