Re: floppy regression from "[PATCH] fix floppy.c to store correct ..."

Jon Masters
2005-11-19T03:46:19Z

On Wed, Nov 16, 2005 at 12:59:58AM -0800, Andrew Morton wrote:
> Cal Peake <cp@absolutedigital.net> wrote:

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

> > causes an annoying side-effect. Upon first write attempt to a floppy I get
> > this:

> > $ dd if=bootdisk.img of=/dev/fd0 bs=1440k
> > dd: writing `/dev/fd0': Operation not permitted
> > 1+0 records in
> > 0+0 records out

Yes indeed. I reproduced that behaviour.

> hmm, yes, when floppy_open() does its test we haven't yet gone and
> determined the state of FD_DISK_WRITABLE. On later opens, we have done, so
> things work OK.

I stuck a test in for first use and had floppy_release free up policy
too. But there are a bunch of problems in the floppy driver I've noticed
in going through it tonight (and there's only so much of that I can take
at 03:43 on a Saturday morning). I'll hopefully followup again.

Jon.

diff -urN linux-2.6.14/drivers/block/floppy.c linux-2.6.14_new/drivers/block/floppy.c
--- 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 2005-11-19 03:17:08.000000000 +0000
@@ -1610,10 +1610,11 @@
DPRINT("wp=%x\n", ST3 & 0x40);
}
#endif
- if (!(ST3 & 0x40))
+ if (!(ST3 & 0x40)) {
SETF(FD_DISK_WRITABLE);
- else
+ } else {
CLEARF(FD_DISK_WRITABLE);
+ }
}
}

@@ -3677,15 +3678,19 @@
int drive = (long)inode->i_bdev->bd_disk->private_data;

down(&open_lock);
+
if (UDRS->fd_ref < 0)
UDRS->fd_ref = 0;
else if (!UDRS->fd_ref--) {
DPRINT("floppy_release with fd_ref == 0");
UDRS->fd_ref = 0;
}
- if (!UDRS->fd_ref)
+ if (!UDRS->fd_ref) {
+ opened_bdev[drive]->bd_disk->policy = 0;
opened_bdev[drive] = NULL;
+ }
floppy_release_irq_and_dma();
+
up(&open_lock);
return 0;
}
@@ -3714,6 +3719,13 @@
USETF(FD_VERIFY);
}

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

@@ -3788,6 +3800,7 @@
if ((filp->f_mode & 2) && !(UTESTF(FD_DISK_WRITABLE)))
goto out;
}
+
up(&open_lock);
return 0;