Re: [Qemu-devel] [PATCH] Add readonly flag to -drive command

[Kevin Wolf]

Am 12.10.2009 15:50, schrieb Jamie Lokier:
> Right now there is already a 'readonly' flag called 'chmod -r image',
> because QEMU opens a file read-only if it can't open it writable, so
> it's not a new case.  Just moving it from the filesystem into QEMU.

Right, but I'm not sure how well it is tested. I think, when moving it
into qemu we should take the opportunity to do it right. If everything
works right now, the right description of it is probably "pure luck".
And I assume you didn't do stupid things like savevm on a read-only
image which we still should be able to handle.

> When opened read-only, it would be better for the block drivers to
> return an error themselves, instead of trying to write and (hopefully)
> getting a host OS error.

For simple read/write operations, the generic block layer is doing the
check already.

Kevin