[dm-devel] LVM snapshot broke between 4.14 and 4.16
snitzer at redhat.com
Fri Aug 3 19:06:17 UTC 2018
On Fri, Aug 03 2018 at 2:57pm -0400,
Linus Torvalds <torvalds at linux-foundation.org> wrote:
> On Fri, Aug 3, 2018 at 11:39 AM Mike Snitzer <snitzer at redhat.com> wrote:
> > Please stop with the overreaction and making this something it isn't.
> It's not an overreaction when people get their scripts broken, and
> some developers then argue "that's not a serious bug".
> Guys, this needs to be fixed. With all the stupid and fundamentyally
> incorrect excuses, I am now no longer even willing to maintain any
> other course of action.
> If you develop for the Linux kernel, you need to realize that
> "breaking user space" is simply not acceptable. And if you cannot live
> with that, then you should stop working on the kernel. Because I will
> refuse to continue to pull from you as a developer.
> At worst, I'll just revert the original commit entirely. I was hoping
> we'd be able to avoid that, partly because the commit looks fine, but
> partly because it also doesn't revert cleanly.
> Or I'll just do something like this, since it seems like it's the lvm
> people who have the hardest time with understanding the simple rules:
I'll be your whipping boy all you like.
But you're making Zdenek's response into mine and threathening to no
longer pull from me.
A block regression that an lvm2 developer papered over.
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index b810ea77e6b1..fcfab812e025 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -1049,7 +1049,12 @@ static int do_resume(struct dm_ioctl *param)
> return PTR_ERR(old_map);
> - if (dm_table_get_mode(new_map) & FMODE_WRITE)
> + /*
> + * This used to do
> + * dm_table_get_mode(new_map) & FMODE_WRITE
> + * but the lvm tools got this wrong, and will
> + * continue to write to "read-only" volumes.
> + if (0)
> set_disk_ro(dm_disk(md), 0);
> set_disk_ro(dm_disk(md), 1);
> which seems to target the actual problem more directly.
How does that pass for a fix to this issue?
That'll unilaterally mark all dm device's readonly.
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