https://bugzilla.redhat.com/show_bug.cgi?id=
1199182 documents that
after a series of disk snapshots into existing destination images,
followed by active commits of the top image, it is possible for
qemu 2.2 and earlier to end up tracking a different name for the
image than what it would have had when opening the chain afresh.
That is, when starting with the chain 'a <- b <- c', the name
associated with 'b' is how it was spelled in the metadata of 'c',
but when starting with 'a', taking two snapshots into 'a <- b <- c',
then committing 'c' back into 'b', the name associated with 'b' is
now the name used when taking the first snapshot.
Sadly, older qemu doesn't know how to treat different spellings of
the same filename as identical files (it uses strcmp() instead of
checking for the same inode), which means libvirt's attempt to
commit an image using solely the names learned from qcow2 metadata
fails with a cryptic:
error: internal error: unable to execute QEMU command 'block-commit': Top image file /tmp/images/c/../b/b not found
even though the file exists. Trying to teach libvirt the rules on
which name qemu will expect is not worth the effort (besides, we'd
have to remember it across libvirtd restarts, and track whether a
file was opened via metadata or via snapshot creation for a given
qemu process); it is easier to just always directly ask qemu what
string it expects to see in the first place.
As a safety valve, we validate that any name returned by qemu
still maps to the same local file as we have tracked it, so that
a compromised qemu cannot accidentally cause us to act on an
incorrect file.
* src/qemu/qemu_monitor.h (qemuMonitorDiskNameLookup): New
prototype.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONDiskNameLookup):
Likewise.
* src/qemu/qemu_monitor.c (qemuMonitorDiskNameLookup): New function.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONDiskNameLookup)
(qemuMonitorJSONDiskNameLookupOne): Likewise.
* src/qemu/qemu_driver.c (qemuDomainBlockCommit)
(qemuDomainBlockJobImpl): Use it.
Signed-off-by: Eric Blake <eblake@redhat.com>
goto endjob;
if (baseSource) {
- if (qemuGetDriveSourceString(baseSource, NULL, &basePath) < 0)
- goto endjob;
-
if (flags & VIR_DOMAIN_BLOCK_REBASE_RELATIVE) {
if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_CHANGE_BACKING_FILE)) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
}
qemuDomainObjEnterMonitor(driver, vm);
- ret = qemuMonitorBlockJob(priv->mon, device, basePath, backingPath,
- speed, mode, async);
+ if (baseSource)
+ basePath = qemuMonitorDiskNameLookup(priv->mon, device, disk->src,
+ baseSource);
+ if (!baseSource || basePath)
+ ret = qemuMonitorBlockJob(priv->mon, device, basePath, backingPath,
+ speed, mode, async);
if (qemuDomainObjExitMonitor(driver, vm) < 0)
ret = -1;
if (ret < 0) {
VIR_DISK_CHAIN_READ_WRITE) < 0))
goto endjob;
- if (qemuGetDriveSourceString(topSource, NULL, &topPath) < 0)
- goto endjob;
-
- if (qemuGetDriveSourceString(baseSource, NULL, &basePath) < 0)
- goto endjob;
-
if (flags & VIR_DOMAIN_BLOCK_COMMIT_RELATIVE &&
topSource != disk->src) {
if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_CHANGE_BACKING_FILE)) {
disk->mirrorJob = VIR_DOMAIN_BLOCK_JOB_TYPE_ACTIVE_COMMIT;
}
qemuDomainObjEnterMonitor(driver, vm);
- ret = qemuMonitorBlockCommit(priv->mon, device,
- topPath, basePath, backingPath,
- speed);
+ basePath = qemuMonitorDiskNameLookup(priv->mon, device, disk->src,
+ baseSource);
+ topPath = qemuMonitorDiskNameLookup(priv->mon, device, disk->src,
+ topSource);
+ if (basePath && topPath)
+ ret = qemuMonitorBlockCommit(priv->mon, device,
+ topPath, basePath, backingPath,
+ speed);
if (qemuDomainObjExitMonitor(driver, vm) < 0) {
ret = -1;
goto endjob;
}
+/* Determine the name that qemu is using for tracking the backing
+ * element TARGET within the chain starting at TOP. */
+char *
+qemuMonitorDiskNameLookup(qemuMonitorPtr mon,
+ const char *device,
+ virStorageSourcePtr top,
+ virStorageSourcePtr target)
+{
+ if (!mon->json) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("JSON monitor is required"));
+ return NULL;
+ }
+
+ return qemuMonitorJSONDiskNameLookup(mon, device, top, target);
+}
+
+
/* Use the block-job-complete monitor command to pivot a block copy
* job. */
int
/*
* qemu_monitor.h: interaction with QEMU monitor console
*
- * Copyright (C) 2006-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2015 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3)
ATTRIBUTE_NONNULL(4);
bool qemuMonitorSupportsActiveCommit(qemuMonitorPtr mon);
+char *qemuMonitorDiskNameLookup(qemuMonitorPtr mon,
+ const char *device,
+ virStorageSourcePtr top,
+ virStorageSourcePtr target)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3)
+ ATTRIBUTE_NONNULL(4);
int qemuMonitorArbitraryCommand(qemuMonitorPtr mon,
const char *cmd,
/*
* qemu_monitor_json.c: interaction with QEMU monitor console
*
- * Copyright (C) 2006-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2015 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
}
+static char *
+qemuMonitorJSONDiskNameLookupOne(virJSONValuePtr image,
+ virStorageSourcePtr top,
+ virStorageSourcePtr target)
+{
+ virJSONValuePtr backing;
+ char *ret;
+
+ /* The caller will report a generic message if we return NULL
+ * without an error; but in some cases we can improve by reporting
+ * a more specific message. */
+ if (!top || !image)
+ return NULL;
+ if (top != target) {
+ backing = virJSONValueObjectGet(image, "backing-image");
+ return qemuMonitorJSONDiskNameLookupOne(backing, top->backingStore,
+ target);
+ }
+ if (VIR_STRDUP(ret, virJSONValueObjectGetString(image, "filename")) < 0)
+ return NULL;
+ /* Sanity check - the name qemu gave us should resolve to the same
+ file tracked by our target description. */
+ if (virStorageSourceIsLocalStorage(target) &&
+ STRNEQ(ret, target->path) &&
+ !virFileLinkPointsTo(ret, target->path)) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("qemu block name '%s' doesn't match expected '%s'"),
+ ret, target->path);
+ VIR_FREE(ret);
+ }
+ return ret;
+}
+
+
+char *
+qemuMonitorJSONDiskNameLookup(qemuMonitorPtr mon,
+ const char *device,
+ virStorageSourcePtr top,
+ virStorageSourcePtr target)
+{
+ char *ret = NULL;
+ virJSONValuePtr cmd = NULL;
+ virJSONValuePtr reply = NULL;
+ virJSONValuePtr devices;
+ size_t i;
+
+ cmd = qemuMonitorJSONMakeCommand("query-block", NULL);
+ if (!cmd)
+ return NULL;
+ if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
+ goto cleanup;
+
+ devices = virJSONValueObjectGet(reply, "return");
+ if (!devices || devices->type != VIR_JSON_TYPE_ARRAY) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("block info reply was missing device list"));
+ goto cleanup;
+ }
+
+ for (i = 0; i < virJSONValueArraySize(devices); i++) {
+ virJSONValuePtr dev = virJSONValueArrayGet(devices, i);
+ virJSONValuePtr inserted;
+ virJSONValuePtr image;
+ const char *thisdev;
+
+ if (!dev || dev->type != VIR_JSON_TYPE_OBJECT) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("block info device entry was not in expected format"));
+ goto cleanup;
+ }
+
+ if (!(thisdev = virJSONValueObjectGetString(dev, "device"))) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("block info device entry was not in expected format"));
+ goto cleanup;
+ }
+
+ if (STREQ(thisdev, device)) {
+ if ((inserted = virJSONValueObjectGet(dev, "inserted")) &&
+ (image = virJSONValueObjectGet(inserted, "image"))) {
+ ret = qemuMonitorJSONDiskNameLookupOne(image, top, target);
+ }
+ break;
+ }
+ }
+ /* Guarantee an error when returning NULL, but don't override a
+ * more specific error if one was already generated. */
+ if (!ret && !virGetLastError())
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("unable to find backing name for device %s"),
+ device);
+
+ cleanup:
+ virJSONValueFree(cmd);
+ virJSONValueFree(reply);
+
+ return ret;
+}
+
+
int qemuMonitorJSONArbitraryCommand(qemuMonitorPtr mon,
const char *cmd_str,
char **reply_str,
/*
* qemu_monitor_json.h: interaction with QEMU monitor console
*
- * Copyright (C) 2006-2009, 2011-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2009, 2011-2015 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
unsigned long long bandwidth)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
+char *qemuMonitorJSONDiskNameLookup(qemuMonitorPtr mon,
+ const char *device,
+ virStorageSourcePtr top,
+ virStorageSourcePtr target)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3)
+ ATTRIBUTE_NONNULL(4);
+
int qemuMonitorJSONArbitraryCommand(qemuMonitorPtr mon,
const char *cmd_str,
char **reply_str,
projects / people / liuw / libxenctrl-split / libvirt.git / commitdiff