On 08/14/2018 07:19 AM, Michal Privoznik wrote:
> Fortunately, we have qemu wrappers so it's sufficient to put
> lock/unlock call only there.
>
Kind of sparse... Maybe a few words related to what benefit locking the
metadata provides. There is a danger in all this too if the unlock does
fail since metadata locks are wait type locks any subsequent lock will wait.
> Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
> ---
> src/qemu/qemu_security.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 107 insertions(+)
>
> diff --git a/src/qemu/qemu_security.c b/src/qemu/qemu_security.c
> index af3be42854..527563947c 100644
> --- a/src/qemu/qemu_security.c
> +++ b/src/qemu/qemu_security.c
> @@ -26,6 +26,7 @@
> #include "qemu_domain.h"
> #include "qemu_security.h"
> #include "virlog.h"
> +#include "locking/domain_lock.h"
>
> #define VIR_FROM_THIS VIR_FROM_QEMU
>
> @@ -39,6 +40,12 @@ qemuSecuritySetAllLabel(virQEMUDriverPtr driver,
> {
> int ret = -1;
> qemuDomainObjPrivatePtr priv = vm->privateData;
> + bool locked = false;
> +
> + if (virDomainLockMetadataLock(driver->lockManager, vm) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -55,9 +62,17 @@ qemuSecuritySetAllLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
Technically not true yet. Also , I think two such attempts with the
second eliciting the VIR_WARN is perfectly reasonable (IOW: on failure
of the following goto cleanup with locked == true, try again, and spew
that message).
This repeats a few times, but I'll note just once.
> +
> + if (virDomainLockMetadataUnlock(driver->lockManager, vm) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataUnlock(driver->lockManager, vm) < 0)
> + VIR_WARN("unable to release metadata lock");
Should we add the @stdin_path and @vm->pid and/or vm->name here? It may
help some day. Similar comments for other new VIR_WARN's, but the
parameters change...
> return ret;
> }
>
> @@ -68,6 +83,10 @@ qemuSecurityRestoreAllLabel(virQEMUDriverPtr driver,
> bool migrated)
> {
> qemuDomainObjPrivatePtr priv = vm->privateData;
> + bool unlock = true;
> +
> + if (virDomainLockMetadataLock(driver->lockManager, vm) < 0)
> + unlock = false;
>
> /* In contrast to qemuSecuritySetAllLabel, do not use
> * secdriver transactions here. This function is called from
> @@ -79,6 +98,10 @@ qemuSecurityRestoreAllLabel(virQEMUDriverPtr driver,
> vm->def,
> migrated,
> priv->chardevStdioLogd);
> +
> + if (unlock &&
> + virDomainLockMetadataUnlock(driver->lockManager, vm) < 0)
> + VIR_WARN("unable to release metadata lock");
> }
>
>
> @@ -88,6 +111,12 @@ qemuSecuritySetDiskLabel(virQEMUDriverPtr driver,
> virDomainDiskDefPtr disk)
> {
> int ret = -1;
> + bool locked = false;
> +
> + if (virDomainLockMetadataDiskLock(driver->lockManager, vm, disk) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -103,9 +132,17 @@ qemuSecuritySetDiskLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
> +
> + if (virDomainLockMetadataDiskUnlock(driver->lockManager, vm, disk) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataDiskUnlock(driver->lockManager, vm, disk) < 0)
> + VIR_WARN("unable to release disk metadata lock");
> return ret;
> }
>
> @@ -116,6 +153,12 @@ qemuSecurityRestoreDiskLabel(virQEMUDriverPtr driver,
> virDomainDiskDefPtr disk)
> {
> int ret = -1;
> + bool locked = false;
> +
> + if (virDomainLockMetadataDiskLock(driver->lockManager, vm, disk) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -131,9 +174,17 @@ qemuSecurityRestoreDiskLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
> +
> + if (virDomainLockMetadataDiskUnlock(driver->lockManager, vm, disk) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataDiskUnlock(driver->lockManager, vm, disk) < 0)
> + VIR_WARN("unable to release disk metadata lock");
> return ret;
> }
>
> @@ -144,6 +195,12 @@ qemuSecuritySetImageLabel(virQEMUDriverPtr driver,
> virStorageSourcePtr src)
> {
> int ret = -1;
> + bool locked = false;
> +
> + if (virDomainLockMetadataImageLock(driver->lockManager, vm, src) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -159,9 +216,17 @@ qemuSecuritySetImageLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
> +
> + if (virDomainLockMetadataImageUnlock(driver->lockManager, vm, src) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataImageUnlock(driver->lockManager, vm, src) < 0)
> + VIR_WARN("unable to release image metadata lock");
> return ret;
> }
>
> @@ -172,6 +237,12 @@ qemuSecurityRestoreImageLabel(virQEMUDriverPtr driver,
> virStorageSourcePtr src)
> {
> int ret = -1;
> + bool locked = false;
> +
> + if (virDomainLockMetadataImageLock(driver->lockManager, vm, src) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -187,9 +258,17 @@ qemuSecurityRestoreImageLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
> +
> + if (virDomainLockMetadataImageUnlock(driver->lockManager, vm, src) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataImageUnlock(driver->lockManager, vm, src) < 0)
> + VIR_WARN("unable to release image metadata lock");
> return ret;
> }
>
Just below here is HostdevLabel processing... For a SCSI host device
that would seem to cover the type of resource described in the cover
letter to patch6 - at least for iSCSI LUNs (and of course vHBA LUNs).
Need to look at the hostdev->mode and hostdev->source.subsys.type and
dig into the subsys.u.scsi to get to the src->path.
Other than that nothing else sticks out to me.
John
> @@ -258,6 +337,12 @@ qemuSecuritySetMemoryLabel(virQEMUDriverPtr driver,
> virDomainMemoryDefPtr mem)
> {
> int ret = -1;
> + bool locked = false;
> +
> + if (virDomainLockMetadataMemLock(driver->lockManager, vm, mem) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -273,9 +358,17 @@ qemuSecuritySetMemoryLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
> +
> + if (virDomainLockMetadataMemUnlock(driver->lockManager, vm, mem) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataMemUnlock(driver->lockManager, vm, mem) < 0)
> + VIR_WARN("unable to release memory metadata lock");
> return ret;
> }
>
> @@ -286,6 +379,12 @@ qemuSecurityRestoreMemoryLabel(virQEMUDriverPtr driver,
> virDomainMemoryDefPtr mem)
> {
> int ret = -1;
> + bool locked = false;
> +
> + if (virDomainLockMetadataMemLock(driver->lockManager, vm, mem) < 0)
> + goto cleanup;
> +
> + locked = true;
>
> if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
> virSecurityManagerTransactionStart(driver->securityManager) < 0)
> @@ -301,9 +400,17 @@ qemuSecurityRestoreMemoryLabel(virQEMUDriverPtr driver,
> vm->pid) < 0)
> goto cleanup;
>
> + locked = false;
> +
> + if (virDomainLockMetadataMemUnlock(driver->lockManager, vm, mem) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virSecurityManagerTransactionAbort(driver->securityManager);
> + if (locked &&
> + virDomainLockMetadataMemUnlock(driver->lockManager, vm, mem) < 0)
> + VIR_WARN("unable to release memory metadata lock");
> return ret;
> }
>
>
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