[libvirt] [PATCH 02/10] qemu: migration: Refactor code now that we assume support for fd migration
Peter Krempa
pkrempa at redhat.com
Tue Feb 16 15:29:44 UTC 2016
After removing capability check for fd migration the code that was left
behind didn't make quite sense. The old exec migration would be used in
case when pipe() failed. Remove the old code and make failure of pipe()
a hard error.
This additionally removes usage of virCgroupAllowDevicePath outside of
qemu_cgroup.c.
---
src/qemu/qemu_driver.c | 4 +-
src/qemu/qemu_migration.c | 114 ++++++++++++++++------------------------------
src/qemu/qemu_migration.h | 2 +-
3 files changed, 41 insertions(+), 79 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2bbc724..fa1d9b7 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -3187,7 +3187,7 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver,
goto cleanup;
/* Perform the migration */
- if (qemuMigrationToFile(driver, vm, fd, offset, path,
+ if (qemuMigrationToFile(driver, vm, fd, path,
qemuCompressProgramName(compressed),
bypassSecurityDriver,
asyncJob) < 0)
@@ -3690,7 +3690,7 @@ doCoreDump(virQEMUDriverPtr driver,
if (!qemuMigrationIsAllowed(driver, vm, false, 0))
goto cleanup;
- ret = qemuMigrationToFile(driver, vm, fd, 0, path,
+ ret = qemuMigrationToFile(driver, vm, fd, path,
qemuCompressProgramName(compress), false,
QEMU_ASYNC_JOB_DUMP);
}
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index f2c7b61..f3b84c8 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -5940,7 +5940,7 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
/* Helper function called while vm is active. */
int
qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
- int fd, off_t offset, const char *path,
+ int fd, const char *path,
const char *compressor,
bool bypassSecurityDriver,
qemuDomainAsyncJob asyncJob)
@@ -5972,54 +5972,28 @@ qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
return -1;
}
- if ((!compressor || pipe(pipeFD) == 0)) {
- /* All right! We can use fd migration, which means that qemu
- * doesn't have to open() the file, so while we still have to
- * grant SELinux access, we can do it on fd and avoid cleanup
- * later, as well as skip futzing with cgroup. */
- if (virSecurityManagerSetImageFDLabel(driver->securityManager, vm->def,
- compressor ? pipeFD[1] : fd) < 0)
- goto cleanup;
- bypassSecurityDriver = true;
- } else {
- /* Phooey - we have to fall back on exec migration, where qemu
- * has to popen() the file by name, and block devices have to be
- * given cgroup ACL permission. We might also stumble on
- * a race present in some qemu versions where it does a wait()
- * that botches pclose. */
- if (virCgroupHasController(priv->cgroup,
- VIR_CGROUP_CONTROLLER_DEVICES)) {
- int rv = virCgroupAllowDevicePath(priv->cgroup, path,
- VIR_CGROUP_DEVICE_RW);
- virDomainAuditCgroupPath(vm, priv->cgroup, "allow", path, "rw", rv == 0);
- if (rv == 1) {
- /* path was not a device, no further need for cgroup */
- } else if (rv < 0) {
- goto cleanup;
- }
- }
- if ((!bypassSecurityDriver) &&
- virSecurityManagerSetSavedStateLabel(driver->securityManager,
- vm->def, path) < 0)
- goto cleanup;
- restoreLabel = true;
+ if (compressor && pipe(pipeFD) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Failed to create pipe for migration"));
+ return -1;
}
+ /* All right! We can use fd migration, which means that qemu
+ * doesn't have to open() the file, so while we still have to
+ * grant SELinux access, we can do it on fd and avoid cleanup
+ * later, as well as skip futzing with cgroup. */
+ if (virSecurityManagerSetImageFDLabel(driver->securityManager, vm->def,
+ compressor ? pipeFD[1] : fd) < 0)
+ goto cleanup;
+ bypassSecurityDriver = true;
+
if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
goto cleanup;
if (!compressor) {
- const char *args[] = { "cat", NULL };
-
- if (priv->monConfig->type == VIR_DOMAIN_CHR_TYPE_UNIX) {
- rc = qemuMonitorMigrateToFd(priv->mon,
- QEMU_MONITOR_MIGRATE_BACKGROUND,
- fd);
- } else {
- rc = qemuMonitorMigrateToFile(priv->mon,
- QEMU_MONITOR_MIGRATE_BACKGROUND,
- args, path, offset);
- }
+ rc = qemuMonitorMigrateToFd(priv->mon,
+ QEMU_MONITOR_MIGRATE_BACKGROUND,
+ fd);
} else {
const char *prog = compressor;
const char *args[] = {
@@ -6027,33 +6001,28 @@ qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
"-c",
NULL
};
- if (pipeFD[0] != -1) {
- cmd = virCommandNewArgs(args);
- virCommandSetInputFD(cmd, pipeFD[0]);
- virCommandSetOutputFD(cmd, &fd);
- virCommandSetErrorBuffer(cmd, &errbuf);
- virCommandDoAsyncIO(cmd);
- if (virSetCloseExec(pipeFD[1]) < 0) {
- virReportSystemError(errno, "%s",
- _("Unable to set cloexec flag"));
- ignore_value(qemuDomainObjExitMonitor(driver, vm));
- goto cleanup;
- }
- if (virCommandRunAsync(cmd, NULL) < 0) {
- ignore_value(qemuDomainObjExitMonitor(driver, vm));
- goto cleanup;
- }
- rc = qemuMonitorMigrateToFd(priv->mon,
- QEMU_MONITOR_MIGRATE_BACKGROUND,
- pipeFD[1]);
- if (VIR_CLOSE(pipeFD[0]) < 0 ||
- VIR_CLOSE(pipeFD[1]) < 0)
- VIR_WARN("failed to close intermediate pipe");
- } else {
- rc = qemuMonitorMigrateToFile(priv->mon,
- QEMU_MONITOR_MIGRATE_BACKGROUND,
- args, path, offset);
+
+ cmd = virCommandNewArgs(args);
+ virCommandSetInputFD(cmd, pipeFD[0]);
+ virCommandSetOutputFD(cmd, &fd);
+ virCommandSetErrorBuffer(cmd, &errbuf);
+ virCommandDoAsyncIO(cmd);
+ if (virSetCloseExec(pipeFD[1]) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to set cloexec flag"));
+ ignore_value(qemuDomainObjExitMonitor(driver, vm));
+ goto cleanup;
}
+ if (virCommandRunAsync(cmd, NULL) < 0) {
+ ignore_value(qemuDomainObjExitMonitor(driver, vm));
+ goto cleanup;
+ }
+ rc = qemuMonitorMigrateToFd(priv->mon,
+ QEMU_MONITOR_MIGRATE_BACKGROUND,
+ pipeFD[1]);
+ if (VIR_CLOSE(pipeFD[0]) < 0 ||
+ VIR_CLOSE(pipeFD[1]) < 0)
+ VIR_WARN("failed to close intermediate pipe");
}
if (qemuDomainObjExitMonitor(driver, vm) < 0)
goto cleanup;
@@ -6105,13 +6074,6 @@ qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
vm->def, path) < 0)
VIR_WARN("failed to restore save state label on %s", path);
- if (virCgroupHasController(priv->cgroup,
- VIR_CGROUP_CONTROLLER_DEVICES)) {
- int rv = virCgroupDenyDevicePath(priv->cgroup, path,
- VIR_CGROUP_DEVICE_RWM);
- virDomainAuditCgroupPath(vm, priv->cgroup, "deny", path, "rwm", rv == 0);
- }
-
if (orig_err) {
virSetError(orig_err);
virFreeError(orig_err);
diff --git a/src/qemu/qemu_migration.h b/src/qemu/qemu_migration.h
index 2445e13..fd94d6e 100644
--- a/src/qemu/qemu_migration.h
+++ b/src/qemu/qemu_migration.h
@@ -177,7 +177,7 @@ bool qemuMigrationIsAllowed(virQEMUDriverPtr driver, virDomainObjPtr vm,
bool remote, unsigned int flags);
int qemuMigrationToFile(virQEMUDriverPtr driver, virDomainObjPtr vm,
- int fd, off_t offset, const char *path,
+ int fd, const char *path,
const char *compressor,
bool bypassSecurityDriver,
qemuDomainAsyncJob asyncJob)
--
2.6.2
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