Explicitly CCing danpb to clarify usage of the logging daemon. On Thu, Feb 20, 2020 at 15:32:48 +0100, Ján Tomko wrote:
Start virtiofsd for each <filesystem> device using it.
Pre-create the socket for communication with QEMU and pass it to virtiofsd.
Note that virtiofsd needs to run as root.
https://bugzilla.redhat.com/show_bug.cgi?id=1694166
Introduced by QEMU commit a43efa34c7d7b628cbf1ec0fe60043e5c91043ea
Signed-off-by: Ján Tomko <jtomko@redhat.com> ---
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diff --git a/src/qemu/qemu_virtiofs.c b/src/qemu/qemu_virtiofs.c new file mode 100644 index 0000000000..600a3644bd --- /dev/null +++ b/src/qemu/qemu_virtiofs.c @@ -0,0 +1,300 @@
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+char * +qemuVirtioFSCreatePidFilename(virQEMUDriverConfigPtr cfg, + const virDomainDef *def, + const char *alias) +{ + g_autofree char *shortName = NULL; + g_autofree char *name = NULL; + + if (!(shortName = virDomainDefGetShortName(def))) + return NULL; + + name = g_strdup_printf("%s-%s-virtiofsd", shortName, alias); + + return virPidFileBuildPath(cfg->stateDir, name); +}
Why do we want to store the pid file here?
+ + +char * +qemuVirtioFSCreateSocketFilename(virDomainObjPtr vm, + const char *alias) +{ + qemuDomainObjPrivatePtr priv = vm->privateData; + + return virFileBuildPath(priv->libDir, alias, "-virtiofsd.sock");
Shouldn't we put it here as well? It's a sub-process of the domain itself and doesn't make much sense to treat it as the qemu pid file.
+}
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+static int +qemuVirtioFSOpenChardev(virQEMUDriverPtr driver, + virDomainObjPtr vm, + const char *socket_path) +{ + virDomainChrSourceDefPtr chrdev = virDomainChrSourceDefNew(NULL); + virDomainChrDef chr = { .source = chrdev }; + VIR_AUTOCLOSE fd = -1; + int ret = -1; + + chrdev->type = VIR_DOMAIN_CHR_TYPE_UNIX; + chrdev->data.nix.listen = true; + chrdev->data.nix.path = g_strdup(socket_path); + + if (qemuSecuritySetDaemonSocketLabel(driver->securityManager, vm->def) < 0) + goto cleanup; + fd = qemuOpenChrChardevUNIXSocket(chrdev); + if (fd < 0) { + ignore_value(qemuSecurityClearSocketLabel(driver->securityManager, vm->def)); + goto cleanup; + } + if (qemuSecurityClearSocketLabel(driver->securityManager, vm->def) < 0) + goto cleanup; + + if (qemuSecuritySetChardevLabel(driver, vm, &chr) < 0) + goto cleanup; + + ret = fd; + fd = -1; + + cleanup: + virObjectUnref(chrdev); + return ret; +} + +static virCommandPtr
Inconsistent spacing between functions.
+qemuVirtioFSBuildCommandLine(virQEMUDriverConfigPtr cfg, + virDomainFSDefPtr fs, + int *fd) +{ + g_autoptr(virCommand) cmd = NULL; + g_auto(virBuffer) opts = VIR_BUFFER_INITIALIZER; + + if (!(cmd = virCommandNew(fs->binary))) + return NULL; + + virCommandAddArgFormat(cmd, "--fd=%d", *fd); + virCommandPassFD(cmd, *fd, VIR_COMMAND_PASS_FD_CLOSE_PARENT); + *fd = -1; + + virCommandAddArg(cmd, "-o"); + virBufferAsprintf(&opts, "source=%s,", fs->src->path);
Since the path is an argument of -o along with others you must escape commas in the path.
+ if (fs->cache) + virBufferAsprintf(&opts, "cache=%s,", virDomainFSCacheModeTypeToString(fs->cache)); + + if (fs->xattr == VIR_TRISTATE_SWITCH_ON) + virBufferAddLit(&opts, "xattr,"); + else if (fs->xattr == VIR_TRISTATE_SWITCH_OFF) + virBufferAddLit(&opts, "no_xattr,"); + + if (fs->flock == VIR_TRISTATE_SWITCH_ON) + virBufferAddLit(&opts, "flock,"); + else if (fs->flock == VIR_TRISTATE_SWITCH_OFF) + virBufferAddLit(&opts, "no_flock,"); + + if (fs->posix_lock == VIR_TRISTATE_SWITCH_ON) + virBufferAddLit(&opts, "posix_lock,"); + else if (fs->posix_lock == VIR_TRISTATE_SWITCH_OFF) + virBufferAddLit(&opts, "no_posix_lock,"); + + virBufferTrim(&opts, ","); + + virCommandAddArgBuffer(cmd, &opts); + if (cfg->virtiofsdDebug) + virCommandAddArg(cmd, "-d"); + + return g_steal_pointer(&cmd); +} + +int +qemuVirtioFSStart(virLogManagerPtr logManager, + virQEMUDriverPtr driver, + virDomainObjPtr vm, + virDomainFSDefPtr fs) +{ + g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver); + g_autoptr(virCommand) cmd = NULL; + g_autofree char *socket_path = NULL; + g_autofree char *pidfile = NULL; + g_autofree char *logpath = NULL; + pid_t pid = (pid_t) -1; + VIR_AUTOCLOSE fd = -1; + VIR_AUTOCLOSE logfd = -1; + int ret = -1; + int rc; + + if (!virFileExists(fs->src->path)) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("the virtiofs export directory '%s' does not exist"), + fs->src->path); + return -1; + } + + if (!(pidfile = qemuVirtioFSCreatePidFilename(cfg, vm->def, fs->info.alias))) + goto cleanup; + + if (!(socket_path = qemuVirtioFSCreateSocketFilename(vm, fs->info.alias))) + goto cleanup; + + if ((fd = qemuVirtioFSOpenChardev(driver, vm, socket_path)) < 0) + goto cleanup; + + logpath = qemuVirtioFSCreateLogFilename(cfg, vm->def, fs->info.alias); + + if (cfg->stdioLogD) { + if ((logfd = virLogManagerDomainOpenLogFile(logManager, + "qemu", + vm->def->uuid, + vm->def->name, + logpath, + 0, + NULL, NULL)) < 0)
Hmm, I'm not sure now what the intented usage of uuid/domname was and there's no docs. Daniel, please review this.
+ goto cleanup; + } else { + if ((logfd = open(logpath, O_WRONLY | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR)) < 0) { + virReportSystemError(errno, _("failed to create logfile %s"), + logpath); + goto cleanup; + } + if (virSetCloseExec(logfd) < 0) { + virReportSystemError(errno, _("failed to set close-on-exec flag on %s"), + logpath); + goto error; + } + } + + if (!(cmd = qemuVirtioFSBuildCommandLine(cfg, fs, &fd))) + goto cleanup; + + /* so far only running as root is supported */ + virCommandSetUID(cmd, 0); + virCommandSetGID(cmd, 0);
Is it necessary to special-case this for cases when we run the session connection? Or is it necessary to forbid usage of virtiofs?
+ virCommandSetPidFile(cmd, pidfile); + virCommandSetOutputFD(cmd, &logfd); + virCommandSetErrorFD(cmd, &logfd); + virCommandNonblockingFDs(cmd); + virCommandDaemonize(cmd); + + if (qemuExtDeviceLogCommand(driver, vm, cmd, "virtiofsd") < 0) + goto cleanup; +
The rest looks good to me.