From a4504ac184c8fa5c30856a58e2f26f1a5db3fb90 Mon Sep 17 00:00:00 2001 From: Osier Yang Date: Wed, 20 Feb 2013 15:43:55 +0800 Subject: [PATCH] qemu: Record names of domain which uses the shared disk in hash table The hash entry is changed from "ref" to {ref, @domains}. With this, the caller can simply call qemuRemoveSharedDisk, without afraid of removing the entry belongs to other domains. qemuProcessStart will obviously benifit from it on error codepath (which calls qemuProcessStop to do the cleanup). --- src/qemu/qemu_conf.c | 169 +++++++++++++++++++++++++++++++++++----- src/qemu/qemu_conf.h | 22 +++++- src/qemu/qemu_driver.c | 6 +- src/qemu/qemu_process.c | 4 +- 4 files changed, 173 insertions(+), 28 deletions(-) diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index e54227f920..8299b7969e 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -824,6 +824,11 @@ qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver, qemuDriverUnlock(driver); } +struct _qemuSharedDiskEntry { + size_t ref; + char **domains; /* array of domain names */ +}; + /* Construct the hash key for sharedDisks as "major:minor" */ char * qemuGetSharedDiskKey(const char *disk_path) @@ -858,10 +863,9 @@ static int qemuCheckSharedDisk(virHashTablePtr sharedDisks, virDomainDiskDefPtr disk) { - int val; - size_t *ref = NULL; char *sysfs_path = NULL; char *key = NULL; + int val; int ret = 0; /* The only conflicts between shared disk we care about now @@ -881,7 +885,6 @@ qemuCheckSharedDisk(virHashTablePtr sharedDisks, if (!virFileExists(sysfs_path)) goto cleanup; - if (!(key = qemuGetSharedDiskKey(disk->src))) { ret = -1; goto cleanup; @@ -890,7 +893,7 @@ qemuCheckSharedDisk(virHashTablePtr sharedDisks, /* It can't be conflict if no other domain is * is sharing it. */ - if (!(ref = virHashLookup(sharedDisks, key))) + if (!(virHashLookup(sharedDisks, key))) goto cleanup; if (virGetDeviceUnprivSGIO(disk->src, NULL, &val) < 0) { @@ -916,14 +919,84 @@ cleanup: return ret; } -/* Increase ref count if the entry already exists, otherwise - * add a new entry. +bool +qemuSharedDiskEntryDomainExists(qemuSharedDiskEntryPtr entry, + const char *name, + int *idx) +{ + size_t i; + + for (i = 0; i < entry->ref; i++) { + if (STREQ(entry->domains[i], name)) { + if (idx) + *idx = i; + return true; + } + } + + return false; +} + +void +qemuSharedDiskEntryFree(void *payload, const void *name ATTRIBUTE_UNUSED) +{ + qemuSharedDiskEntryPtr entry = payload; + size_t i; + + for (i = 0; i < entry->ref; i++) { + VIR_FREE(entry->domains[i]); + } + VIR_FREE(entry->domains); + VIR_FREE(entry); +} + +static qemuSharedDiskEntryPtr +qemuSharedDiskEntryCopy(const qemuSharedDiskEntryPtr entry) +{ + qemuSharedDiskEntryPtr ret = NULL; + size_t i; + + if (VIR_ALLOC(ret) < 0) { + virReportOOMError(); + return NULL; + } + + if (VIR_ALLOC_N(ret->domains, entry->ref) < 0) { + virReportOOMError(); + goto cleanup; + } + + for (i = 0; i < entry->ref; i++) { + if (!(ret->domains[i] = strdup(entry->domains[i]))) { + virReportOOMError(); + goto cleanup; + } + ret->ref++; + } + + return ret; + +cleanup: + qemuSharedDiskEntryFree(ret, NULL); + return NULL; +} + +/* qemuAddSharedDisk: + * @driver: Pointer to qemu driver struct + * @disk: The disk def + * @name: The domain name + * + * Increase ref count and add the domain name into the list which + * records all the domains that use the shared disk if the entry + * already exists, otherwise add a new entry. */ int qemuAddSharedDisk(virQEMUDriverPtr driver, - virDomainDiskDefPtr disk) + virDomainDiskDefPtr disk, + const char *name) { - size_t *ref = NULL; + qemuSharedDiskEntry *entry = NULL; + qemuSharedDiskEntry *new_entry = NULL; char *key = NULL; int ret = -1; @@ -942,11 +1015,40 @@ qemuAddSharedDisk(virQEMUDriverPtr driver, if (!(key = qemuGetSharedDiskKey(disk->src))) goto cleanup; - if ((ref = virHashLookup(driver->sharedDisks, key))) { - if (virHashUpdateEntry(driver->sharedDisks, key, ++ref) < 0) - goto cleanup; + if ((entry = virHashLookup(driver->sharedDisks, key))) { + /* Nothing to do if the shared disk is already recorded + * in the table. + */ + if (qemuSharedDiskEntryDomainExists(entry, name, NULL)) { + ret = 0; + goto cleanup; + } + + if (!(new_entry = qemuSharedDiskEntryCopy(entry))) + goto cleanup; + + if ((VIR_EXPAND_N(new_entry->domains, new_entry->ref, 1) < 0) || + !(new_entry->domains[new_entry->ref - 1] = strdup(name))) { + qemuSharedDiskEntryFree(new_entry, NULL); + virReportOOMError(); + goto cleanup; + } + + if (virHashUpdateEntry(driver->sharedDisks, key, new_entry) < 0) { + qemuSharedDiskEntryFree(new_entry, NULL); + goto cleanup; + } } else { - if (virHashAddEntry(driver->sharedDisks, key, (void *)0x1)) + if ((VIR_ALLOC(entry) < 0) || + (VIR_ALLOC_N(entry->domains, 1) < 0) || + !(entry->domains[0] = strdup(name))) { + virReportOOMError(); + goto cleanup; + } + + entry->ref = 1; + + if (virHashAddEntry(driver->sharedDisks, key, entry)) goto cleanup; } @@ -957,16 +1059,25 @@ cleanup: return ret; } -/* Decrease the ref count if the entry already exists, otherwise - * remove the entry. +/* qemuRemoveSharedDisk: + * @driver: Pointer to qemu driver struct + * @disk: The disk def + * @name: The domain name + * + * Decrease ref count and remove the domain name from the list which + * records all the domains that use the shared disk if ref is not 1, + * otherwise remove the entry. */ int qemuRemoveSharedDisk(virQEMUDriverPtr driver, - virDomainDiskDefPtr disk) + virDomainDiskDefPtr disk, + const char *name) { - size_t *ref = NULL; + qemuSharedDiskEntryPtr entry = NULL; + qemuSharedDiskEntryPtr new_entry = NULL; char *key = NULL; int ret = -1; + int idx; if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK || !disk->shared || !disk->src) @@ -976,12 +1087,32 @@ qemuRemoveSharedDisk(virQEMUDriverPtr driver, if (!(key = qemuGetSharedDiskKey(disk->src))) goto cleanup; - if (!(ref = virHashLookup(driver->sharedDisks, key))) + if (!(entry = virHashLookup(driver->sharedDisks, key))) goto cleanup; - if (ref != (void *)0x1) { - if (virHashUpdateEntry(driver->sharedDisks, key, --ref) < 0) + /* Nothing to do if the shared disk is not recored in + * the table. + */ + if (!qemuSharedDiskEntryDomainExists(entry, name, &idx)) { + ret = 0; + goto cleanup; + } + + if (entry->ref != 1) { + if (!(new_entry = qemuSharedDiskEntryCopy(entry))) + goto cleanup; + + if (idx != new_entry->ref - 1) + memmove(&new_entry->domains[idx], + &new_entry->domains[idx + 1], + sizeof(*new_entry->domains) * (new_entry->ref - idx - 1)); + + VIR_SHRINK_N(new_entry->domains, new_entry->ref, 1); + + if (virHashUpdateEntry(driver->sharedDisks, key, new_entry) < 0){ + qemuSharedDiskEntryFree(new_entry, NULL); goto cleanup; + } } else { if (virHashRemoveEntry(driver->sharedDisks, key) < 0) goto cleanup; diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index 6ae33ae698..87d8b77cd4 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -272,16 +272,30 @@ qemuDriverCloseCallback qemuDriverCloseCallbackGet(virQEMUDriverPtr driver, void qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver, virConnectPtr conn); -int qemuAddSharedDisk(virQEMUDriverPtr driver, - virDomainDiskDefPtr disk) +typedef struct _qemuSharedDiskEntry qemuSharedDiskEntry; +typedef qemuSharedDiskEntry *qemuSharedDiskEntryPtr; + +bool qemuSharedDiskEntryDomainExists(qemuSharedDiskEntryPtr entry, + const char *name, + int *index) ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2); +int qemuAddSharedDisk(virQEMUDriverPtr driver, + virDomainDiskDefPtr disk, + const char *name) + ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3); + int qemuRemoveSharedDisk(virQEMUDriverPtr driver, - virDomainDiskDefPtr disk) - ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2); + virDomainDiskDefPtr disk, + const char *name) + ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3); + char * qemuGetSharedDiskKey(const char *disk_path) ATTRIBUTE_NONNULL(1); +void qemuSharedDiskEntryFree(void *payload, const void *name) + ATTRIBUTE_NONNULL(1); + int qemuDriverAllocateID(virQEMUDriverPtr driver); #endif /* __QEMUD_CONF_H */ diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 813411db2f..3025d1d4e0 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -681,7 +681,7 @@ qemuStartup(bool privileged, if ((qemu_driver->inactivePciHostdevs = virPCIDeviceListNew()) == NULL) goto error; - if (!(qemu_driver->sharedDisks = virHashCreate(30, NULL))) + if (!(qemu_driver->sharedDisks = virHashCreate(30, qemuSharedDiskEntryFree))) goto error; if (privileged) { @@ -5766,7 +5766,7 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn, } if (ret == 0) { - if (qemuAddSharedDisk(driver, disk) < 0) + if (qemuAddSharedDisk(driver, disk, vm->def->name) < 0) VIR_WARN("Failed to add disk '%s' to shared disk table", disk->src); @@ -5890,7 +5890,7 @@ qemuDomainDetachDeviceDiskLive(virQEMUDriverPtr driver, } if (ret == 0) { - if (qemuRemoveSharedDisk(driver, disk) < 0) + if (qemuRemoveSharedDisk(driver, disk, vm->def->name) < 0) VIR_WARN("Failed to remove disk '%s' from shared disk table", disk->src); } diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index a925d61d97..95ed6c0658 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3830,7 +3830,7 @@ int qemuProcessStart(virConnectPtr conn, _("Raw I/O is not supported on this platform")); #endif - if (qemuAddSharedDisk(driver, disk) < 0) + if (qemuAddSharedDisk(driver, disk, vm->def->name) < 0) goto cleanup; if (qemuSetUnprivSGIO(disk) < 0) @@ -4235,7 +4235,7 @@ void qemuProcessStop(virQEMUDriverPtr driver, for (i = 0; i < vm->def->ndisks; i++) { virDomainDiskDefPtr disk = vm->def->disks[i]; - ignore_value(qemuRemoveSharedDisk(driver, disk)); + ignore_value(qemuRemoveSharedDisk(driver, disk, vm->def->name)); } /* Clear out dynamically assigned labels */ -- 2.39.5