[libvirt] [PATCH v3] qemu: Don't fail if the SCSI host device is shareable between domains

[Osier Yang]

On 23/01/14 23:04, Osier Yang wrote:
> It doesn't make sense to fail if the SCSI host device is specified
> as "shareable" explicitly between domains (NB, it works if and only
> if the device is specified as "shareable" for *all* domains,
> otherwise it fails).
>
> To fix the problem, this patch introduces an array for virSCSIDevice
> struct, which records all the names of domain which are using the
> device (note that the recorded domains must specifiy the device as
> shareable).  And the change on the data struct brings on many
> subsequent changes in the code.
>
> Since prior to this patch, the "shareable" tag didn't work as expected,
> it actually work like "non-shareable".  If there was a live domain using
> the SCSI device with "shareable" specified, then after upgrading
> (assuming the live domain keep running during upgrading) the older
> libvirt (without this patch) to newer libvirt (with this patch), it may
> cause some confusion when user tries to start later domains as
> "shareable". So this patch also added notes in formatdomain.html to
> declare the fact.
>
> * src/util/virscsi.h:
>    - Remove virSCSIDeviceGetUsedBy
>    - Change definition of virSCSIDeviceGetUsedBy and virSCSIDeviceListDel
>    - Add virSCSIDeviceIsAvailable
>
> * src/util/virscsi.c:
>    - struct virSCSIDevice: Change "used_by" to be an array; Add
>      "n_used_by" as the array count
>    - virSCSIDeviceGetUsedBy: Removed
>    - virSCSIDeviceFree: frees the "used_by" array
>    - virSCSIDeviceSetUsedBy: Copy the domain name to avoid potential
>      memory corruption
>    - virSCSIDeviceIsAvailable: New
>    - virSCSIDeviceListDel: Change the logic, for device which is already
>      in the list, just remove the corresponding entry in "used_by". And
>      since it's only used in one place, we can safely removing the code
>      to find out the dev in the list first.
>    - Copyright updating
>
> * src/libvirt_private.sys:
>    - virSCSIDeviceGetUsedBy: Remove
>    - virSCSIDeviceIsAvailable: New
>
> * src/qemu/qemu_hostdev.c:
>    - qemuUpdateActiveScsiHostdevs: Check if the device existing before
>      adding it to the list;
>    - qemuPrepareHostdevSCSIDevices: Error out if the not all domains
>      use the device as "shareable"; Also don't try to add the device
>      to the activeScsiHostdevs list if it already there; And make
>      more sensible error w.r.t the current "shareable" value in
>      driver->activeScsiHostdevs.
>    - qemuDomainReAttachHostScsiDevices: Change the logic according
>      to the changes on helpers.
> ---
>   docs/formatdomain.html.in |  6 ++++
>   src/libvirt_private.syms  |  2 +-
>   src/qemu/qemu_hostdev.c   | 77 ++++++++++++++++++++++++++---------------------
>   src/util/virscsi.c        | 45 +++++++++++++++++++++------
>   src/util/virscsi.h        |  7 +++--
>   5 files changed, 90 insertions(+), 47 deletions(-)
>
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index ff50214..18bfad1 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -2798,6 +2798,12 @@
>           between domains (assuming the hypervisor and OS support this).
>           Only supported by SCSI host device.
>           <span class="since">Since 1.0.6</span>
> +        <p>
> +          Note: though <code>shareable</shareable> was introduced
>

s/shareable/code/,  :(