NFS: fsync() must exit with an error if page writeback failed

We need to ensure that if the call to filemap_write_and_wait_range()
fails, then we report that error back to the application.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/file.c

@@ -287,10 +287,12 @@ nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	struct inode *inode = file->f_path.dentry->d_inode;
 
 	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (ret != 0)
+		goto out;
 	mutex_lock(&inode->i_mutex);
 	ret = nfs_file_fsync_commit(file, start, end, datasync);
 	mutex_unlock(&inode->i_mutex);
-
+out:
 	return ret;
 }
 

fs/nfs/nfs4file.c

@@ -96,13 +96,15 @@ nfs4_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	struct inode *inode = file->f_path.dentry->d_inode;
 
 	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+	if (ret != 0)
+		goto out;
 	mutex_lock(&inode->i_mutex);
 	ret = nfs_file_fsync_commit(file, start, end, datasync);
 	if (!ret && !datasync)
 		/* application has asked for meta-data sync */
 		ret = pnfs_layoutcommit_inode(inode, true);
 	mutex_unlock(&inode->i_mutex);
-
+out:
 	return ret;
 }