From 2c49be99ede1e3685a9817a564b4b1678d48e1b9 Mon Sep 17 00:00:00 2001
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Date: Sun, 1 May 2005 08:58:57 -0700
Subject: [PATCH] uml ubd: handle readonly status
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 <blaisorblade@yahoo.it>
CC: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
arch/um/drivers/ubd_kern.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
(limited to 'arch/um')
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 4d8b165bfa48..9a56ff94308d 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -156,6 +156,7 @@ static struct gendisk *fake_gendisk[MAX_DEV];
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, struct file *filp)
}
}
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 request *req, struct io_thread_req *io_req)
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, unsigned long address, int is_write,
/* 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 "
--
cgit