Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261737AbVDYT1O (ORCPT ); Mon, 25 Apr 2005 15:27:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262768AbVDYT1N (ORCPT ); Mon, 25 Apr 2005 15:27:13 -0400 Received: from mail-relay-3.tiscali.it ([213.205.33.43]:40667 "EHLO mail-relay-3.tiscali.it") by vger.kernel.org with ESMTP id S261737AbVDYTXy (ORCPT ); Mon, 25 Apr 2005 15:23:54 -0400 Subject: [patch 1/1] uml ubd: handle readonly status To: akpm@osdl.org Cc: jdike@addtoit.com, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, blaisorblade@yahoo.it, axboe@suse.de From: blaisorblade@yahoo.it Date: Mon, 25 Apr 2005 21:19:49 +0200 Message-Id: <20050425191949.E56D145EBB@zion> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2755 Lines: 78 CC: Jens Axboe Use the set_disk_ro() API when the backing file is read-only, to mark the disk read-only, during the ->open(). The current hack does not work when doing a mount -o remount. Also, mark explicitly the code paths which should no more be triggerable (I've removed the WARN_ON(1) things). They should actually become BUG()s probably but I'll avoid that since I'm not so sure the change works so well. I gave it only some limited testing. Signed-off-by: Paolo 'Blaisorblade' Giarrusso --- linux-2.6.12-paolo/arch/um/drivers/ubd_kern.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-) diff -puN arch/um/drivers/ubd_kern.c~uml-ubd-handle-readonly arch/um/drivers/ubd_kern.c --- linux-2.6.12/arch/um/drivers/ubd_kern.c~uml-ubd-handle-readonly 2005-04-25 21:16:03.000000000 +0200 +++ linux-2.6.12-paolo/arch/um/drivers/ubd_kern.c 2005-04-25 21:16:47.000000000 +0200 @@ -156,6 +156,7 @@ static struct gendisk *fake_gendisk[MAX_ static struct openflags global_openflags = OPEN_FLAGS; struct cow { + /* This is the backing file, actually */ char *file; int fd; unsigned long *bitmap; @@ -927,10 +928,14 @@ static int ubd_open(struct inode *inode, } } dev->count++; - if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){ + set_disk_ro(disk, !dev->openflags.w); + + /* This should no more be needed. And it didn't work anyway to exclude + * read-write remounting of filesystems.*/ + /*if((filp->f_mode & FMODE_WRITE) && !dev->openflags.w){ if(--dev->count == 0) ubd_close(dev); err = -EROFS; - } + }*/ out: return(err); } @@ -1096,6 +1101,7 @@ static int prepare_request(struct reques if(req->rq_status == RQ_INACTIVE) return(1); + /* This should be impossible now */ if((rq_data_dir(req) == WRITE) && !dev->openflags.w){ printk("Write attempted on readonly ubd device %s\n", disk->disk_name); @@ -1243,6 +1249,7 @@ static int ubd_check_remapped(int fd, un /* It's a write to a ubd device */ + /* This should be impossible now */ if(!dev->openflags.w){ /* It's a write access on a read-only device - probably * shouldn't happen. If the kernel is trying to change @@ -1605,8 +1612,7 @@ void do_io(struct io_thread_req *req) } } while((n < len) && (n != 0)); if (n < len) memset(&buf[n], 0, len - n); - } - else { + } else { n = os_write_file(req->fds[bit], buf, len); if(n != len){ printk("do_io - write failed err = %d " _ - 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/