[libvirt] [PATCHv2 13/16] save: support BYPASS_CACHE during qemu save/restore
Eric Blake
eblake at redhat.com
Wed Jul 20 04:20:36 UTC 2011
Wire together the previous patches to support file system cache
bypass during API save/restore requests in qemu.
* src/qemu/qemu_driver.c (qemuDomainSaveInternal, doCoreDump)
(qemudDomainObjStart, qemuDomainSaveImageOpen, qemuDomainObjRestore)
(qemuDomainObjStart): Add parameter.
(qemuDomainSaveFlags, qemuDomainManagedSave, qemudDomainCoreDump)
(processWatchdogEvent, qemudDomainStartWithFlags, qemuAutostartDomain)
(qemuDomainRestoreFlags): Update callers.
---
v2: merge 8 and 16 of v1, and rebase to renamed flags and new
virFileDirectFdFlag call done earlier in this series
src/qemu/qemu_driver.c | 161 ++++++++++++++++++++++++++++++++++--------------
1 files changed, 115 insertions(+), 46 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 95f30c3..f6166c2 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -116,11 +116,12 @@ static void processWatchdogEvent(void *data, void *opaque);
static int qemudShutdown(void);
-static int qemudDomainObjStart(virConnectPtr conn,
- struct qemud_driver *driver,
- virDomainObjPtr vm,
- bool start_paused,
- bool autodestroy);
+static int qemuDomainObjStart(virConnectPtr conn,
+ struct qemud_driver *driver,
+ virDomainObjPtr vm,
+ bool start_paused,
+ bool autodestroy,
+ bool bypass_cache);
static int qemudDomainGetMaxVcpus(virDomainPtr dom);
@@ -148,9 +149,11 @@ qemuAutostartDomain(void *payload, const void *name ATTRIBUTE_UNUSED, void *opaq
vm->def->name,
err ? err->message : _("unknown error"));
} else {
+ /* XXX need to wire bypass-cache autostart into qemu.conf */
if (vm->autostart &&
!virDomainObjIsActive(vm) &&
- qemudDomainObjStart(data->conn, data->driver, vm, false, false) < 0) {
+ qemuDomainObjStart(data->conn, data->driver, vm,
+ false, false, false) < 0) {
err = virGetLastError();
VIR_ERROR(_("Failed to autostart VM '%s': %s"),
vm->def->name,
@@ -2110,7 +2113,7 @@ qemuCompressProgramName(int compress)
static int
qemuDomainSaveInternal(struct qemud_driver *driver, virDomainPtr dom,
virDomainObjPtr vm, const char *path,
- int compressed)
+ int compressed, bool bypass_cache)
{
char *xml = NULL;
struct qemud_save_header header;
@@ -2125,6 +2128,8 @@ qemuDomainSaveInternal(struct qemud_driver *driver, virDomainPtr dom,
int fd = -1;
uid_t uid = getuid();
gid_t gid = getgid();
+ int directFlag = 0;
+ virFileDirectFdPtr directFd = NULL;
memset(&header, 0, sizeof(header));
memcpy(header.magic, QEMUD_SAVE_MAGIC, sizeof(header.magic));
@@ -2207,15 +2212,23 @@ qemuDomainSaveInternal(struct qemud_driver *driver, virDomainPtr dom,
/* Obtain the file handle. */
/* First try creating the file as root */
+ if (bypass_cache) {
+ directFlag = virFileDirectFdFlag();
+ if (directFlag < 0) {
+ qemuReportError(VIR_ERR_OPERATION_FAILED, "%s",
+ _("bypass cache unsupported by this system"));
+ goto endjob;
+ }
+ }
if (!is_reg) {
- fd = open(path, O_WRONLY | O_TRUNC);
+ fd = open(path, O_WRONLY | O_TRUNC | directFlag);
if (fd < 0) {
virReportSystemError(errno, _("unable to open %s"), path);
goto endjob;
}
} else {
- if ((fd = virFileOpenAs(path, O_CREAT|O_TRUNC|O_WRONLY,
- S_IRUSR|S_IWUSR,
+ int oflags = O_CREAT | O_TRUNC | O_WRONLY | directFlag;
+ if ((fd = virFileOpenAs(path, oflags, S_IRUSR | S_IWUSR,
uid, gid, 0)) < 0) {
/* If we failed as root, and the error was permission-denied
(EACCES or EPERM), assume it's on a network-connected share
@@ -2261,7 +2274,7 @@ qemuDomainSaveInternal(struct qemud_driver *driver, virDomainPtr dom,
/* Retry creating the file as driver->user */
- if ((fd = virFileOpenAs(path, O_CREAT|O_TRUNC|O_WRONLY,
+ if ((fd = virFileOpenAs(path, oflags,
S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP,
driver->user, driver->group,
VIR_FILE_OPEN_AS_UID)) < 0) {
@@ -2279,6 +2292,9 @@ qemuDomainSaveInternal(struct qemud_driver *driver, virDomainPtr dom,
}
}
+ if (bypass_cache && (directFd = virFileDirectFdNew(&fd, path)) == NULL)
+ goto endjob;
+
/* Write header to file, followed by XML */
if (qemuDomainSaveHeader(fd, path, xml, &header) < 0) {
VIR_FORCE_CLOSE(fd);
@@ -2294,6 +2310,8 @@ qemuDomainSaveInternal(struct qemud_driver *driver, virDomainPtr dom,
virReportSystemError(errno, _("unable to close %s"), path);
goto endjob;
}
+ if (virFileDirectFdClose(directFd) < 0)
+ goto endjob;
ret = 0;
@@ -2326,6 +2344,7 @@ endjob:
cleanup:
VIR_FORCE_CLOSE(fd);
+ virFileDirectFdFree(directFd);
VIR_FREE(xml);
if (ret != 0 && is_reg)
unlink(path);
@@ -2361,7 +2380,7 @@ qemuDomainSaveFlags(virDomainPtr dom, const char *path, const char *dxml,
int ret = -1;
virDomainObjPtr vm = NULL;
- virCheckFlags(0, -1);
+ virCheckFlags(VIR_DOMAIN_SAVE_BYPASS_CACHE, -1);
if (dxml) {
qemuReportError(VIR_ERR_INVALID_ARG, "%s",
_("xml modification unsupported"));
@@ -2403,7 +2422,8 @@ qemuDomainSaveFlags(virDomainPtr dom, const char *path, const char *dxml,
goto cleanup;
}
- ret = qemuDomainSaveInternal(driver, dom, vm, path, compressed);
+ ret = qemuDomainSaveInternal(driver, dom, vm, path, compressed,
+ (flags & VIR_DOMAIN_SAVE_BYPASS_CACHE) != 0);
vm = NULL;
cleanup:
@@ -2441,7 +2461,7 @@ qemuDomainManagedSave(virDomainPtr dom, unsigned int flags)
int ret = -1;
int compressed;
- virCheckFlags(0, -1);
+ virCheckFlags(VIR_DOMAIN_SAVE_BYPASS_CACHE, -1);
qemuDriverLock(driver);
vm = virDomainFindByUUID(&driver->domains, dom->uuid);
@@ -2466,7 +2486,8 @@ qemuDomainManagedSave(virDomainPtr dom, unsigned int flags)
VIR_INFO("Saving state to %s", name);
compressed = QEMUD_SAVE_FORMAT_RAW;
- ret = qemuDomainSaveInternal(driver, dom, vm, name, compressed);
+ ret = qemuDomainSaveInternal(driver, dom, vm, name, compressed,
+ (flags & VIR_DOMAIN_SAVE_BYPASS_CACHE) != 0);
vm = NULL;
cleanup:
@@ -2550,18 +2571,33 @@ static int
doCoreDump(struct qemud_driver *driver,
virDomainObjPtr vm,
const char *path,
- enum qemud_save_formats compress)
+ enum qemud_save_formats compress,
+ bool bypass_cache)
{
int fd = -1;
int ret = -1;
+ virFileDirectFdPtr directFd = NULL;
+ int directFlag = 0;
/* Create an empty file with appropriate ownership. */
- if ((fd = open(path, O_CREAT|O_TRUNC|O_WRONLY, S_IRUSR|S_IWUSR)) < 0) {
+ if (bypass_cache) {
+ directFlag = virFileDirectFdFlag();
+ if (directFlag < 0) {
+ qemuReportError(VIR_ERR_OPERATION_FAILED, "%s",
+ _("bypass cache unsupported by this system"));
+ goto cleanup;
+ }
+ }
+ if ((fd = open(path, O_CREAT | O_TRUNC | O_WRONLY | directFlag,
+ S_IRUSR | S_IWUSR)) < 0) {
qemuReportError(VIR_ERR_OPERATION_FAILED,
_("failed to create '%s'"), path);
goto cleanup;
}
+ if (bypass_cache && (directFd = virFileDirectFdNew(&fd, path)) == NULL)
+ goto cleanup;
+
if (qemuMigrationToFile(driver, vm, fd, 0, path,
qemuCompressProgramName(compress), true, false) < 0)
goto cleanup;
@@ -2572,11 +2608,14 @@ doCoreDump(struct qemud_driver *driver,
path);
goto cleanup;
}
+ if (virFileDirectFdClose(directFd) < 0)
+ goto cleanup;
ret = 0;
cleanup:
VIR_FORCE_CLOSE(fd);
+ virFileDirectFdClose(directFd);
if (ret != 0)
unlink(path);
return ret;
@@ -2620,7 +2659,7 @@ static int qemudDomainCoreDump(virDomainPtr dom,
int ret = -1;
virDomainEventPtr event = NULL;
- virCheckFlags(VIR_DUMP_LIVE | VIR_DUMP_CRASH, -1);
+ virCheckFlags(VIR_DUMP_LIVE | VIR_DUMP_CRASH | VIR_DUMP_BYPASS_CACHE, -1);
qemuDriverLock(driver);
vm = virDomainFindByUUID(&driver->domains, dom->uuid);
@@ -2661,7 +2700,8 @@ static int qemudDomainCoreDump(virDomainPtr dom,
}
}
- ret = doCoreDump(driver, vm, path, getCompressionType(driver));
+ ret = doCoreDump(driver, vm, path, getCompressionType(driver),
+ (flags & VIR_DUMP_BYPASS_CACHE) != 0);
if (ret < 0)
goto endjob;
@@ -2832,10 +2872,9 @@ static void processWatchdogEvent(void *data, void *opaque)
goto endjob;
}
- ret = doCoreDump(driver,
- wdEvent->vm,
- dumpfile,
- getCompressionType(driver));
+ /* XXX wire up qemu.conf to support bypass-cache dumps */
+ ret = doCoreDump(driver, wdEvent->vm, dumpfile,
+ getCompressionType(driver), false);
if (ret < 0)
qemuReportError(VIR_ERR_OPERATION_FAILED,
"%s", _("Dump failed"));
@@ -3572,18 +3611,29 @@ cleanup:
return ret;
}
-static int ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4)
+static int ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4) ATTRIBUTE_NONNULL(6)
qemuDomainSaveImageOpen(struct qemud_driver *driver,
const char *path,
virDomainDefPtr *ret_def,
- struct qemud_save_header *ret_header)
+ struct qemud_save_header *ret_header,
+ bool bypass_cache, virFileDirectFdPtr *directFd)
{
int fd;
struct qemud_save_header header;
char *xml = NULL;
virDomainDefPtr def = NULL;
+ int directFlag = 0;
- if ((fd = virFileOpenAs(path, O_RDONLY, 0, getuid(), getgid(), 0)) < 0) {
+ if (bypass_cache) {
+ directFlag = virFileDirectFdFlag();
+ if (directFlag < 0) {
+ qemuReportError(VIR_ERR_OPERATION_FAILED, "%s",
+ _("bypass cache unsupported by this system"));
+ goto error;
+ }
+ }
+ if ((fd = virFileOpenAs(path, O_RDONLY | directFlag, 0,
+ getuid(), getgid(), 0)) < 0) {
if ((fd != -EACCES && fd != -EPERM) ||
driver->user == getuid()) {
qemuReportError(VIR_ERR_OPERATION_FAILED,
@@ -3593,7 +3643,7 @@ qemuDomainSaveImageOpen(struct qemud_driver *driver,
/* Opening as root failed, but qemu runs as a different user
* that might have better luck. */
- if ((fd = virFileOpenAs(path, O_RDONLY, 0,
+ if ((fd = virFileOpenAs(path, O_RDONLY | directFlag, 0,
driver->user, driver->group,
VIR_FILE_OPEN_AS_UID)) < 0) {
qemuReportError(VIR_ERR_OPERATION_FAILED,
@@ -3601,6 +3651,8 @@ qemuDomainSaveImageOpen(struct qemud_driver *driver,
goto error;
}
}
+ if (bypass_cache && (*directFd = virFileDirectFdNew(&fd, path)) == NULL)
+ goto error;
if (saferead(fd, &header, sizeof(header)) != sizeof(header)) {
qemuReportError(VIR_ERR_OPERATION_FAILED,
@@ -3779,8 +3831,9 @@ qemuDomainRestoreFlags(virConnectPtr conn,
int fd = -1;
int ret = -1;
struct qemud_save_header header;
+ virFileDirectFdPtr directFd = NULL;
- virCheckFlags(0, -1);
+ virCheckFlags(VIR_DOMAIN_SAVE_BYPASS_CACHE, -1);
if (dxml) {
qemuReportError(VIR_ERR_INVALID_ARG, "%s",
_("xml modification unsupported"));
@@ -3789,7 +3842,9 @@ qemuDomainRestoreFlags(virConnectPtr conn,
qemuDriverLock(driver);
- fd = qemuDomainSaveImageOpen(driver, path, &def, &header);
+ fd = qemuDomainSaveImageOpen(driver, path, &def, &header,
+ (flags & VIR_DOMAIN_SAVE_BYPASS_CACHE) != 0,
+ &directFd);
if (fd < 0)
goto cleanup;
@@ -3808,6 +3863,8 @@ qemuDomainRestoreFlags(virConnectPtr conn,
goto cleanup;
ret = qemuDomainSaveImageStartVM(conn, driver, vm, &fd, &header, path);
+ if (virFileDirectFdClose(directFd) < 0)
+ VIR_WARN("Failed to close %s", path);
if (qemuDomainObjEndJob(driver, vm) == 0)
vm = NULL;
@@ -3819,6 +3876,7 @@ qemuDomainRestoreFlags(virConnectPtr conn,
cleanup:
virDomainDefFree(def);
VIR_FORCE_CLOSE(fd);
+ virFileDirectFdFree(directFd);
if (vm)
virDomainObjUnlock(vm);
qemuDriverUnlock(driver);
@@ -3836,14 +3894,17 @@ static int
qemuDomainObjRestore(virConnectPtr conn,
struct qemud_driver *driver,
virDomainObjPtr vm,
- const char *path)
+ const char *path,
+ bool bypass_cache)
{
virDomainDefPtr def = NULL;
int fd = -1;
int ret = -1;
struct qemud_save_header header;
+ virFileDirectFdPtr directFd = NULL;
- fd = qemuDomainSaveImageOpen(driver, path, &def, &header);
+ fd = qemuDomainSaveImageOpen(driver, path, &def, &header,
+ bypass_cache, &directFd);
if (fd < 0)
goto cleanup;
@@ -3865,10 +3926,13 @@ qemuDomainObjRestore(virConnectPtr conn,
def = NULL;
ret = qemuDomainSaveImageStartVM(conn, driver, vm, &fd, &header, path);
+ if (virFileDirectFdClose(directFd) < 0)
+ VIR_WARN("Failed to close %s", path);
cleanup:
virDomainDefFree(def);
VIR_FORCE_CLOSE(fd);
+ virFileDirectFdFree(directFd);
return ret;
}
@@ -4082,11 +4146,13 @@ static int qemudNumDefinedDomains(virConnectPtr conn) {
}
-static int qemudDomainObjStart(virConnectPtr conn,
- struct qemud_driver *driver,
- virDomainObjPtr vm,
- bool start_paused,
- bool autodestroy)
+static int
+qemuDomainObjStart(virConnectPtr conn,
+ struct qemud_driver *driver,
+ virDomainObjPtr vm,
+ bool start_paused,
+ bool autodestroy,
+ bool bypass_cache)
{
int ret = -1;
char *managed_save;
@@ -4101,7 +4167,8 @@ static int qemudDomainObjStart(virConnectPtr conn,
goto cleanup;
if (virFileExists(managed_save)) {
- ret = qemuDomainObjRestore(conn, driver, vm, managed_save);
+ ret = qemuDomainObjRestore(conn, driver, vm, managed_save,
+ bypass_cache);
if ((ret == 0) && (unlink(managed_save) < 0))
VIR_WARN("Failed to remove the managed state %s", managed_save);
@@ -4127,14 +4194,15 @@ cleanup:
}
static int
-qemudDomainStartWithFlags(virDomainPtr dom, unsigned int flags)
+qemuDomainStartWithFlags(virDomainPtr dom, unsigned int flags)
{
struct qemud_driver *driver = dom->conn->privateData;
virDomainObjPtr vm;
int ret = -1;
virCheckFlags(VIR_DOMAIN_START_PAUSED |
- VIR_DOMAIN_START_AUTODESTROY, -1);
+ VIR_DOMAIN_START_AUTODESTROY |
+ VIR_DOMAIN_START_BYPASS_CACHE, -1);
qemuDriverLock(driver);
vm = virDomainFindByUUID(&driver->domains, dom->uuid);
@@ -4156,9 +4224,10 @@ qemudDomainStartWithFlags(virDomainPtr dom, unsigned int flags)
goto endjob;
}
- if (qemudDomainObjStart(dom->conn, driver, vm,
- (flags & VIR_DOMAIN_START_PAUSED) != 0,
- (flags & VIR_DOMAIN_START_AUTODESTROY) != 0) < 0)
+ if (qemuDomainObjStart(dom->conn, driver, vm,
+ (flags & VIR_DOMAIN_START_PAUSED) != 0,
+ (flags & VIR_DOMAIN_START_AUTODESTROY) != 0,
+ (flags & VIR_DOMAIN_START_BYPASS_CACHE) != 0) < 0)
goto endjob;
ret = 0;
@@ -4175,9 +4244,9 @@ cleanup:
}
static int
-qemudDomainStart(virDomainPtr dom)
+qemuDomainStart(virDomainPtr dom)
{
- return qemudDomainStartWithFlags(dom, 0);
+ return qemuDomainStartWithFlags(dom, 0);
}
static int
@@ -8616,8 +8685,8 @@ static virDriver qemuDriver = {
.domainXMLToNative = qemuDomainXMLToNative, /* 0.6.4 */
.listDefinedDomains = qemudListDefinedDomains, /* 0.2.0 */
.numOfDefinedDomains = qemudNumDefinedDomains, /* 0.2.0 */
- .domainCreate = qemudDomainStart, /* 0.2.0 */
- .domainCreateWithFlags = qemudDomainStartWithFlags, /* 0.8.2 */
+ .domainCreate = qemuDomainStart, /* 0.2.0 */
+ .domainCreateWithFlags = qemuDomainStartWithFlags, /* 0.8.2 */
.domainDefineXML = qemudDomainDefine, /* 0.2.0 */
.domainUndefine = qemudDomainUndefine, /* 0.2.0 */
.domainUndefineFlags = qemuDomainUndefineFlags, /* 0.9.4 */
--
1.7.4.4
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