[libvirt] [PATCH 3/6] qemu: Record names of domain which uses the shared disk in hash table
John Ferlan
jferlan at redhat.com
Tue Feb 19 18:57:41 UTC 2013
On 02/19/2013 07:27 AM, Osier Yang wrote:
> 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 | 163 +++++++++++++++++++++++++++++++++++++++++------
> src/qemu/qemu_conf.h | 26 ++++++-
> src/qemu/qemu_driver.c | 6 +-
> src/qemu/qemu_process.c | 4 +-
> 4 files changed, 171 insertions(+), 28 deletions(-)
>
> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> index e54227f..a0477b3 100644
> --- a/src/qemu/qemu_conf.c
> +++ b/src/qemu/qemu_conf.c
> @@ -858,10 +858,9 @@ 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 +880,6 @@ qemuCheckSharedDisk(virHashTablePtr sharedDisks,
> if (!virFileExists(sysfs_path))
> goto cleanup;
>
> -
> if (!(key = qemuGetSharedDiskKey(disk->src))) {
> ret = -1;
> goto cleanup;
> @@ -890,7 +888,7 @@ 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 +914,83 @@ 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)
> +{
> + int 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 = (qemuSharedDiskEntryPtr)payload;
> + int i;
> +
> + for (i = 0; i < entry->ref; i++) {
> + VIR_FREE(entry->domains[i]);
> + }
> + VIR_FREE(entry->domains);
Do we need to VIR_FREE(entry)?
There's a VIR_ALLOC(ret) below, followed by VIR_ALLOC_N(ret->domains),
followed by strdup(entry->domains[i]);
> +}
> +
> +static qemuSharedDiskEntryPtr
> +qemuSharedDiskEntryCopy(const qemuSharedDiskEntryPtr entry)
> +{
> + qemuSharedDiskEntryPtr ret = NULL;
> + int 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 +1009,40 @@ 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;
> + }
If this is successful, then shouldn't the former 'entry' now be
DiskEntryFree'd since you've successfully replaced the former 'entry'
with 'new_entry' in the hash table (eg, payload = new data structure?
> } 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 +1053,25 @@ 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 +1081,32 @@ qemuRemoveSharedDisk(virQEMUDriverPtr driver,
> if (!(key = qemuGetSharedDiskKey(disk->src)))
> goto cleanup;
>
> - if (!(ref = virHashLookup(driver->sharedDisks, key)))
> + if (!(entry = virHashLookup(driver->sharedDisks, key)))
> + goto cleanup;
> +
> + /* 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));
>
> - if (ref != (void *)0x1) {
> - if (virHashUpdateEntry(driver->sharedDisks, key, --ref) < 0)
> + VIR_SHRINK_N(new_entry->domains, new_entry->ref, 1);
> +
> + if (virHashUpdateEntry(driver->sharedDisks, key, new_entry) < 0){
> + qemuSharedDiskEntryFree(new_entry, NULL);
> goto cleanup;
> + }
Same comment as above. 'new_entry' is now in the hash - the old 'entry'
can be DiskEntryFree()'d right?
> } else {
> if (virHashRemoveEntry(driver->sharedDisks, key) < 0)
> goto cleanup;
> diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
> index 81a001b..d3cd0a1 100644
> --- a/src/qemu/qemu_conf.h
> +++ b/src/qemu/qemu_conf.h
> @@ -272,16 +272,34 @@ qemuDriverCloseCallback qemuDriverCloseCallbackGet(virQEMUDriverPtr driver,
> void qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver,
> virConnectPtr conn);
>
> -int qemuAddSharedDisk(virQEMUDriverPtr driver,
> - virDomainDiskDefPtr disk)
> +typedef struct _qemuSharedDiskEntry qemuSharedDiskEntry;
> +typedef qemuSharedDiskEntry *qemuSharedDiskEntryPtr;
> +struct _qemuSharedDiskEntry {
> + size_t ref;
> + char **domains; /* array of domain names */
> +};
> +
> +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 5ebe3fa..27d3daf 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -679,7 +679,7 @@ 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) {
> @@ -5762,7 +5762,7 @@ 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);
>
> @@ -5886,7 +5886,7 @@ 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 e955260..69e4209 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -3831,7 +3831,7 @@ 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)
> @@ -4237,7 +4237,7 @@ 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 */
>
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