Re: [libvirt] [PATCH 2/8 v8] qemu: Add a hash table for the shared disks

This introduces a hash table for qemu driver, to store the shared disk's info as (@disk_path, @ref_count). @ref_count is the number

of domains which shares the disk. Since we only care about the disk's cdbfilter (see later patch) setting for shared disk currently, and cdbfilter is only valid for block disk, this patch only manages (add/remove hash entry) the shared disk for block disk. * src/qemu/qemu_conf.h: (Add member 'sharedDisks' of type virHashTablePtr; Declare helpers qemuGetSharedDiskKey, qemuAddSharedDisk and qemuRemoveSharedDisk) * src/qemu/qemu_conf.c (Implement the 3 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). --- src/qemu/qemu_conf.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_conf.h | 12 ++++++ src/qemu/qemu_driver.c | 22 ++++++++++++ src/qemu/qemu_process.c | 15 ++++++++ 4 files changed, 135 insertions(+), 0 deletions(-) diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index a1b1d04..e25376d 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -553,3 +553,89 @@ qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver, virHashForEach(driver->closeCallbacks, qemuDriverCloseCallbackRun, &data); } + +/* Construct the hash key for sharedDisks as "major:minor" */ +char * +qemuGetSharedDiskKey(const char *disk_path) +{ + int major, minor; + char *key = NULL; + int rc; + + if ((rc = virGetDeviceID(disk_path, &major, &minor)) < 0) { + virReportSystemError(-rc, + _("Unable to get minor number of device '%s'"), + disk_path); + return NULL; + }

+ + if (virAsprintf(&key, "%d:%d", major, minor) < 0) { + virReportOOMError(); + return NULL; + } + + return key; +} + +/* Increase ref count if the entry already exists, otherwise + * add a new entry. + */ +int +qemuAddSharedDisk(virHashTablePtr sharedDisks, + const char *disk_path) +{ + size_t *ref = NULL; + char *key = NULL; + + if (!(key = qemuGetSharedDiskKey(disk_path))) + return -1;

@@ -6041,6 +6045,15 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn, VIR_WARN("Failed to teardown cgroup for disk path %s", NULLSTR(disk->src)); } + + if (ret == 0 && + disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK && + disk->shared) {