[libvirt] [PATCHv3 18/19] blockjob: refactor qemu disk chain permission grants
Eric Blake
eblake at redhat.com
Fri Oct 19 23:54:20 UTC 2012
On 10/18/2012 12:50 PM, Laine Stump wrote:
> On 10/17/2012 06:30 PM, Eric Blake wrote:
>> Previously, snapshot code did its own permission granting (lock
>> manager, cgroup device controller, and security manager labeling)
>> inline. But now that we are adding block-commit and block-copy
>> which also have to change permissions, it's better to reuse
>> common code for the task. While snapshot should fall back to
>> no access if read-write access failed, block-commit will want to
>> fall back to read-only access. The common code doesn't know
>> whether failure to grant read-write access should revert to no
>> access (snapshot, block-copy) or read-only access (block-commit).
>> This code can also be used to revoke access to unused files after
>> block-pull.
>>
>
> ACK, with qualifying remarks from the review of the previous version of
> the patch (PATCHv2 17/16)
I'm adding this to the commit message:
It might be nice to clean things up in a future patch by adding
new functions to the lock manager, cgroup manager, and security
manager that takes a single file name and applies context of a
disk to that file, rather than the current semantics of applying
context to the entire chain already associated to a disk. That
way, we could avoid the games this patch plays of temporarily
swapping out the disk->src and related fields of the disk. But
that would involve more code changes, so this patch really is
the smallest hack for doing the necessary work; besides, this
patch is more or less code motion (the hack was already employed
by the snapshot creation code, we are just making it reusable).
--
Eric Blake eblake at redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 617 bytes
Desc: OpenPGP digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20121019/e893c4e2/attachment-0001.sig>
More information about the libvir-list
mailing list