From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264931AbTLREsL (ORCPT ); Wed, 17 Dec 2003 23:48:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264934AbTLREsL (ORCPT ); Wed, 17 Dec 2003 23:48:11 -0500 Received: from chico.cs.colostate.edu ([129.82.45.30]:17297 "EHLO chico.cs.colostate.edu") by vger.kernel.org with ESMTP id S264931AbTLREsD (ORCPT ); Wed, 17 Dec 2003 23:48:03 -0500 X-WebMail-UserID: jshankar@cs.colostate.edu Date: Wed, 17 Dec 2003 21:47:59 -0700 From: jshankar To: Hans Reiser Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org X-EXP32-SerialNo: 00002247, 00002264 Subject: RE: ext3 file system Message-ID: <3FE23273@webmail.colostate.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Mailer: Infinite Mobile Delivery (Hydra) SMTP v3.62.01 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello Hans, >Filesystems don't usually wait on the IO to complete before submitting >more IO in response to the next write() syscall. They can do this by >batching a whole bunch of operations into one committed transaction. > Is there a timeout mechanism for batching operations. What if certain operation is done after the batch operation is executed. Does it mean that the new operation has to wait. Thanks Jay >===== Original Message From Hans Reiser ===== >jshankar wrote: > >>Hello, >> >>Please provide some more insight. >> >>Suppose a filesystem issues a write command to the disk with around 10 4K >>Blocks to be written. SCSI device point of view i don't get what is the >>parallel I/O. >>It has only 1 write command. If some other sends a write request it needs to >>be queued. But the next question arises how the write data would be handled. >>Does it mean the SCSI does not give a response for the block of data written. >>In otherwords does it mean that the response would be given after all the >>block of data is written for a single write request. >> >>Thanks >>Jay >> >> >> >> >> >> >>>===== Original Message From Mike Fedyk ===== >>>On Wed, Dec 17, 2003 at 05:25:49PM -0500, Richard B. Johnson wrote: >>> >>> >>>to the physical media. There are special file-systems (journaling) >>>that guarantee that something, enough to recover the data, is >>>written at periodic intervals. >>> >>> >>>Most journaling filesystems make guarantees on the filesystem meta-data, but >>>not on the data. Some like ext3, and reiserfs (with suse's journaling >>>patch) can journal the data, or order things so that the data is written >>>before any pointers (ie meta-data) make it to the disk so it will be harder >>>to loose data. >>>- >>>To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in >>>the body of a message to majordomo@vger.kernel.org >>>More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >>> >> >>- >>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/ >> >> >> >> >In reiser4 we do this more carefully than other filesystems such as >reiserfs v3, and as a result every fs operation is fully atomic. > >-- >Hans > > >- >To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html