Re: [libvirt] [PATCH 01/12] 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, @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;

@@ -6035,6 +6039,12 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn, VIR_WARN("Failed to teardown cgroup for disk path %s", NULLSTR(disk->src)); } + + if (ret == 0 && disk->shared) { + if (qemuAddSharedDisk(driver->sharedDisks, disk->src, 0) < 0) + VIR_WARN("Failed to add disk '%s' to shared disk table", + disk->src); + }

end: if (cgroup) virCgroupFree(&cgroup); @@ -6149,6 +6159,13 @@ qemuDomainDetachDeviceDiskLive(virQEMUDriverPtr driver, virDomainDiskDeviceTypeToString(disk->type)); break; } + + if (ret == 0 && disk->shared) { + if (qemuRemoveSharedDisk(driver->sharedDisks, disk->src) < 0) + VIR_WARN("Failed to remove disk '%s' from shared disk table", + disk->src); + }

+ return ret; } diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index ab04599..89152b8 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3706,8 +3706,15 @@ int qemuProcessStart(virConnectPtr conn, /* in case a certain disk is desirous of CAP_SYS_RAWIO, add this */ for (i = 0; i < vm->def->ndisks; i++) { - if (vm->def->disks[i]->rawio == 1) + virDomainDiskDefPtr disk = vm->def->disks[i]; + + if (disk->rawio == 1) virCommandAllowCap(cmd, CAP_SYS_RAWIO); + + if (disk->shared) { + if (qemuAddSharedDisk(driver->sharedDisks, disk->src, 0) < 0) + goto cleanup; + }

} virCommandSetPreExecHook(cmd, qemuProcessHook, &hookData); @@ -4104,6 +4111,14 @@ void qemuProcessStop(virQEMUDriverPtr driver, flags & VIR_QEMU_PROCESS_STOP_MIGRATED); virSecurityManagerReleaseLabel(driver->securityManager, vm->def); + for (i = 0; i < vm->def->ndisks; i++) { + virDomainDiskDefPtr disk = vm->def->disks[i]; + + if (disk->shared) { + ignore_value(qemuRemoveSharedDisk(driver->sharedDisks, disk->src)); + } + }