[PATCH] fix floppy.c to store correct ro/rw status in underlying gendisk

[Jon Masters <jonathan@jonmasters.org>]

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Evgeny Stambulchik found that doing the following always worked:

# mount /dev/fd0 /mnt/floppy/
mount: block device /dev/fd0 is write-protected, mounting read-only
# mount -o remount,rw /mnt/floppy
# echo $?
0

This is the case because the block device /dev/fd0 is writeable but the
floppy disk is marked protected. A fix is to simply have floppy_open
mark the underlying gendisk policy according to reality (since the VFS
doesn't provide a way for do_remount_sb to inquire as to the current
device status).

Signed-off-by: Jon Masters <jcm@jonmasters.org>

- --- linux-2.6.14/drivers/block/floppy.c 2005-10-28 01:02:08.000000000
+0100
+++ linux-2.6.14_new/drivers/block/floppy.c     2005-10-29
18:14:47.000000000 +0100
@@ -3714,6 +3714,13 @@
                USETF(FD_VERIFY);
        }

+       /* set underlying gendisk policy to reflect real ro/rw status */
+       if (UTESTF(FD_DISK_WRITABLE)) {
+               inode->i_bdev->bd_disk->policy = 0;
+       } else {
+               inode->i_bdev->bd_disk->policy = 1;
+       }
+
        if (UDRS->fd_ref == -1 || (UDRS->fd_ref && (filp->f_flags &
O_EXCL)))
                goto out2;
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