From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <4CB70234.3030308@gmail.com> Date: Thu, 14 Oct 2010 15:14:28 +0200 From: Tejun Heo MIME-Version: 1.0 Subject: Re: [PATCH 1/1] um: ubd: Fix data corruption References: <20100928225202.GA30352@foursquare.net> <4CA275CE.6060401@fusionio.com> <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> In-Reply-To: <20101007202339.GA8338@foursquare.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Chris Frey 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" List-ID: 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;