[Libguestfs] [PATCH v3 0/6] launch: direct: Disable qemu locking when opening drives readonly.

[Richard W.M. Jones]

On Thu, Sep 14, 2017 at 04:15:10PM +0300, Roman Kagan wrote:
> What ABI is broken by this?

It's used all over, major tools like virt-tail simply assume that it
works this way.

I'm not disputing that locking in QEMU is valuable, and we can
certainly add a flag to obey locking when readonly=true.

> In fact it was the amount of reports of weird misbehavior of all sorts
> that made us add image locking to QEMU in the first place

This wasn't weird misbehaviour in libguestfs though (or at least no
such reports were ever sent to me).  Libguestfs + qemu 2.10 does
prevent accidental writes which cause corruption and data loss --
that's the important fix.

Rich.

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