Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751593Ab3JTMWP (ORCPT ); Sun, 20 Oct 2013 08:22:15 -0400 Received: from outbound-ss-330.hostmonster.com ([74.220.205.49]:36146 "HELO outbound-ss-330.hostmonster.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751326Ab3JTMWO convert rfc822-to-8bit (ORCPT ); Sun, 20 Oct 2013 08:22:14 -0400 Subject: Re: [RFC] Rollback FS Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Vyacheslav Dubeyko In-Reply-To: Date: Sun, 20 Oct 2013 16:32:12 +0400 Cc: jiaweiwei , "linux-kernel@vger.kernel.org" , Harry Wei Content-Transfer-Encoding: 8BIT Message-Id: <977288EE-C80D-4808-93E6-E019CA1DDC58@dubeyko.com> References: To: Richard Weinberger X-Mailer: Apple Mail (2.1085) X-Identified-User: {2172:host202.hostmonster.com:dubeykoc:dubeyko.com} {sentby:smtp auth 46.39.244.28 authed with slava@dubeyko.com} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1313 Lines: 31 On Oct 20, 2013, at 3:46 PM, Richard Weinberger wrote: > On Sun, Oct 20, 2013 at 1:37 PM, jiaweiwei wrote: >> On Sun, Oct 20, 2013 at 6:43 PM, Vyacheslav Dubeyko wrote: >>> Anyway, you need to use Copy-On-Write (COW) approach for such file system. >>> But there are file systems that implements snapshot approach yet: NILFS2, ext3cow, >>> Next3, and so on. >>> >> >> Any file system should rollback but not specific ones. Therefore, a >> VFS like mechanism should be designed and implemented. > > -ENOPATCH Yes, I doubt also that it makes sense to implement such feature on VFS level only. Anyway, it needs to have support of snapshot feature on concrete file system level. Otherwise, if it doesn't take into account a concrete file system's internal techniques then it will have such nonsense as COW under COW. :) Maybe, VFS needs in transparent rollback support likewise online resize. But such feature should be based on concrete file systems' internal techniques. With the best regards, Vyacheslav Dubeyko. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/