* Re: PATCH: fix block layer ioctl bug
[not found] <1V9VL-3ty-5@gated-at.bofh.it>
@ 2004-10-01 13:56 ` Ed L Cashin
0 siblings, 0 replies; 2+ messages in thread
From: Ed L Cashin @ 2004-10-01 13:56 UTC (permalink / raw)
To: linux-kernel
Alan Cox <alan@redhat.com> writes:
> The block layer checks for -EINVAL from block layer driver ioctls. This
> is wrong - ENOTTY is unknown and some drivers correctly use this. I suspect
> for an internal ioctl 2.7 should change to -ENOIOCTLCMD and bitch about
> old style returns
>
> This is conservative fix for the 2.6 case, it keeps the bogus -EINVAL to
> avoid breaking stuff
>
>
> diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.6/drivers/block/ioctl.c linux-2.6.6/drivers/block/ioctl.c
> --- linux.vanilla-2.6.6/drivers/block/ioctl.c 2004-05-10 03:31:59.000000000 +0100
> +++ linux-2.6.6/drivers/block/ioctl.c 2004-05-11 20:05:09.000000000 +0100
> @@ -203,7 +203,8 @@
> case BLKROSET:
> if (disk->fops->ioctl) {
> ret = disk->fops->ioctl(inode, file, cmd, arg);
> - if (ret != -EINVAL)
> + /* -EINVAL to handle old uncorrected drivers */
> + if (ret != -EINVAL && ret != -ENOTTY)
> return ret;
> }
> if (!capable(CAP_SYS_ADMIN))
There's a case just above BLKROSET that seems to be in need of a
similar change. In 2.6.8.1, on a BLKFLSBUF ioctl, if a driver returns
-EINVAL, the block layer will call fsync_bdev, invalidate_bdev, and
return 0. It only gets the default behavior if it's returning
-EINVAL, though.
If returning -ENOTTY for unhandled ioctls is the correct thing for a
driver to do, shouldn't the BLKFLSBUF ioctl sync the block device when
the driver returns -ENOTTY?
If so, this patch follows the one above, supporting the drivers that
return -ENOTTY correctly as well as the ones that still return
-EINVAL, at least for now.
--- linux-2.6.8.1/drivers/block/ioctl.c.20041001 Fri Oct 1 08:31:52 2004
+++ linux-2.6.8.1/drivers/block/ioctl.c Fri Oct 1 08:42:05 2004
@@ -192,11 +192,12 @@ int blkdev_ioctl(struct inode *inode, st
case BLKFLSBUF:
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (disk->fops->ioctl) {
ret = disk->fops->ioctl(inode, file, cmd, arg);
- if (ret != -EINVAL)
+ /* -EINVAL to handle old uncorrected drivers */
+ if (ret != -EINVAL && ret != -ENOTTY)
return ret;
}
fsync_bdev(bdev);
invalidate_bdev(bdev, 0);
return 0;
--
Ed L Cashin <ecashin@coraid.com>
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