From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753328Ab0JOEtM (ORCPT ); Fri, 15 Oct 2010 00:49:12 -0400 Received: from nic.NetDirect.CA ([216.16.235.2]:58920 "EHLO rubicon.netdirect.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750889Ab0JOEtK (ORCPT ); Fri, 15 Oct 2010 00:49:10 -0400 X-Originating-Ip: 216.16.235.2 Date: Fri, 15 Oct 2010 00:47:56 -0400 From: Chris Frey To: Tejun Heo Cc: Jens Axboe , Richard Weinberger , Andrew Morton , "linux-kernel@vger.kernel.org" , "jdike@addtoit.com" , "user-mode-linux-devel@lists.sourceforge.net" , "user-mode-linux-user@lists.sourceforge.net" , "janjaap@bos.nl" , "geert@linux-m68k.org" , "martin.petersen@oracle.com" , "adobriyan@gmail.com" , "syzop@vulnscan.org" Subject: Re: [PATCH 1/1] um: ubd: Fix data corruption Message-ID: <20101015044756.GA16666@foursquare.net> References: <20100929012945.GA3324@foursquare.net> <4CA2CCC3.8010307@fusionio.com> <20100929063452.GA13290@foursquare.net> <4CAA02D0.7040901@gmail.com> <20101004195152.GA31583@foursquare.net> <4CAAE077.9010500@gmail.com> <20101005203137.GA594@foursquare.net> <4CAD7D98.7080808@fusionio.com> <20101007202339.GA8338@foursquare.net> <4CB70234.3030308@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CB70234.3030308@gmail.com> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 14, 2010 at 03:14:28PM +0200, Tejun Heo wrote: > Hello, > > Can you please try this one then? It seems to work here but I can't > reproduce the original problem reliably so I'm not really sure. > > Thanks. > > diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c > index 1bcd208..9734994 100644 > --- a/arch/um/drivers/ubd_kern.c > +++ b/arch/um/drivers/ubd_kern.c > @@ -163,6 +163,7 @@ struct ubd { > struct scatterlist sg[MAX_SG]; > struct request *request; > int start_sg, end_sg; > + sector_t rq_pos; > }; > > #define DEFAULT_COW { \ > @@ -187,6 +188,7 @@ struct ubd { > .request = NULL, \ > .start_sg = 0, \ > .end_sg = 0, \ > + .rq_pos = 0, \ > } > > /* Protected by ubd_lock */ > @@ -1228,7 +1230,6 @@ static void do_ubd_request(struct request_queue *q) > { > struct io_thread_req *io_req; > struct request *req; > - sector_t sector; > int n; > > while(1){ > @@ -1239,12 +1240,12 @@ static void do_ubd_request(struct request_queue *q) > return; > > dev->request = req; > + dev->rq_pos = blk_rq_pos(req); > dev->start_sg = 0; > dev->end_sg = blk_rq_map_sg(q, req, dev->sg); > } > > req = dev->request; > - sector = blk_rq_pos(req); > while(dev->start_sg < dev->end_sg){ > struct scatterlist *sg = &dev->sg[dev->start_sg]; > > @@ -1256,10 +1257,9 @@ static void do_ubd_request(struct request_queue *q) > return; > } > prepare_request(req, io_req, > - (unsigned long long)sector << 9, > + (unsigned long long)dev->rq_pos << 9, > sg->offset, sg->length, sg_page(sg)); > > - sector += sg->length >> 9; > n = os_write_file(thread_fd, &io_req, > sizeof(struct io_thread_req *)); > if(n != sizeof(struct io_thread_req *)){ > @@ -1272,6 +1272,7 @@ static void do_ubd_request(struct request_queue *q) > return; > } > > + dev->rq_pos += sg->length >> 9; > dev->start_sg++; > } > dev->end_sg = 0; I tested this patch, on 2.6.35.5, as heavily as I could today, and was unable to reproduce the filesystem corruption. Seems to be fixed. :-) Thanks! - Chris