On Tue, Dec 11, 2012 at 09:37:18PM +0800, Osier Yang wrote:
> This introduces a hash table for qemu driver, to store the shared
> disk's info as (@disk_path, {@ref_count, @orig_cdbfilter}). @ref_count
> is the number of domains which shares the disk. @orig_cdbfilter is
> the original cdbfilter setting of the shared disk, it will be used
> to restore the the disk's cdbfilter setting to original value by
> later patches.
>
> * src/qemu/qemu_conf.h: (Add member 'sharedDisks' of type
> virHashTablePtr; New struct qemuSharedDiskEntry;
> Declare helpers qemuAddSharedDisk,
> qemuRemoveSharedDisk)
> * src/qemu/qemu_conf.c (Implement the two helpers)
> * src/qemu/qemu_process.c (Update 'sharedDisks' when domain
> starting and shutdown)
> * src/qemu/qemu_driver.c (Update 'sharedDisks' when attaching
> or detaching disk).
>
> 0 is passed for orig_cdbfilter temporarily, later patches will update
> it.
> ---
> src/qemu/qemu_conf.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
> src/qemu/qemu_conf.h | 18 +++++++++++++++++
> src/qemu/qemu_driver.c | 17 ++++++++++++++++
> src/qemu/qemu_process.c | 17 +++++++++++++++-
> 4 files changed, 99 insertions(+), 1 deletions(-)
>
> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> index 8d380a1..2b21186 100644
> --- a/src/qemu/qemu_conf.c
> +++ b/src/qemu/qemu_conf.c
> @@ -556,3 +556,51 @@ qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver,
>
> virHashForEach(driver->closeCallbacks, qemuDriverCloseCallbackRun, &data);
> }
> +
> +/* Increase ref count if the entry already exists, otherwise
> + * add a new entry.
> + */
> +int
> +qemuAddSharedDisk(virHashTablePtr sharedDisks,
> + const char *disk_path,
> + int orig_cdbfilter)
> +{
> + qemuSharedDiskEntryPtr entry = NULL;
> +
> + if ((entry = virHashLookup(sharedDisks, disk_path))) {
> + entry->ref++;
> + } else {
> + if (VIR_ALLOC(entry) < 0)
> + return -1;
> +
> + entry->ref = 1;
> + entry->orig_cdbfilter = orig_cdbfilter;
> +
> + if (virHashAddEntry(sharedDisks, disk_path, entry))
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +/* Decrease the ref count if the entry already exists, otherwise
> + * remove the entry.
> + */
> +int
> +qemuRemoveSharedDisk(virHashTablePtr sharedDisks,
> + const char *disk_path)
> +{
> + qemuSharedDiskEntryPtr entry = NULL;
> +
> + if (!(entry = virHashLookup(sharedDisks, disk_path)))
> + return -1;
> +
> + if (entry->ref != 1) {
> + entry->ref--;
> + } else {
> + if (virHashRemoveEntry(sharedDisks, disk_path) < 0)
> + return -1;
> + }
> +
> + return 0;
> +}
> diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
> index d0d25ce..df901f6 100644
> --- a/src/qemu/qemu_conf.h
> +++ b/src/qemu/qemu_conf.h
> @@ -147,6 +147,8 @@ struct _virQEMUDriver {
> /* The devices which is are not in use by the host or any guest. */
> pciDeviceList *inactivePciHostdevs;
>
> + virHashTablePtr sharedDisks;
> +
> virBitmapPtr reservedRemotePorts;
>
> virSysinfoDefPtr hostsysinfo;
> @@ -193,6 +195,13 @@ struct qemuDomainDiskInfo {
> int io_status;
> };
>
> +typedef struct qemuSharedDiskEntry qemuSharedDiskEntry;
> +typedef qemuSharedDiskEntry *qemuSharedDiskEntryPtr;
> +struct qemuSharedDiskEntry {
> + size_t ref; /* ref count of the shared disk */
> + int orig_cdbfilter; /* Original disk's cdbfilter setting */
> +};
Storing the original value here doesn't work in context of
libvirtd restarts, because you've no way to re-populate
it
Daniel
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