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authorTomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>2012-12-12 12:55:55 +0900
committerMichael Roth <mdroth@linux.vnet.ibm.com>2013-01-08 16:38:12 -0600
commitec0f694c11e8e0958d727e40e0759ab99e5908d6 (patch)
tree6167bf79990fcde0edf3c0fe862fd7c62619b764
parent7b3760879bf323a0d9654a5158d5b3ed51882505 (diff)
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qemu-ga: execute hook to quiesce the guest on fsfreeze-freeze/thaw
To use the online disk snapshot for online-backup, application-level consistency of the snapshot image is required. However, currently the guest agent can provide only filesystem-level consistency, and the snapshot may contain dirty data, for example, incomplete transactions. This patch provides the opportunity to quiesce applications before snapshot is taken. If --fsfreeze-hook option is specified, the hook is executed with "freeze" argument before the filesystem is frozen by fsfreeze-freeze command. As for fsfreeze-thaw command, the hook is executed with "thaw" argument after the filesystem is thawed. This patch depends on patchset to improve error reporting by Luiz Capitulino: http://lists.gnu.org/archive/html/qemu-devel/2012-11/msg03016.html Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com> *clarified usage in help output Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
-rw-r--r--qga/commands-posix.c69
-rw-r--r--qga/guest-agent-core.h1
-rw-r--r--qga/main.c48
3 files changed, 117 insertions, 1 deletions
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 614a421..77f6ee7 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -410,6 +410,66 @@ static void build_fs_mount_list(FsMountList *mounts, Error **err)
#if defined(CONFIG_FSFREEZE)
+typedef enum {
+ FSFREEZE_HOOK_THAW = 0,
+ FSFREEZE_HOOK_FREEZE,
+} FsfreezeHookArg;
+
+const char *fsfreeze_hook_arg_string[] = {
+ "thaw",
+ "freeze",
+};
+
+static void execute_fsfreeze_hook(FsfreezeHookArg arg, Error **err)
+{
+ int status;
+ pid_t pid;
+ const char *hook;
+ const char *arg_str = fsfreeze_hook_arg_string[arg];
+ Error *local_err = NULL;
+
+ hook = ga_fsfreeze_hook(ga_state);
+ if (!hook) {
+ return;
+ }
+ if (access(hook, X_OK) != 0) {
+ error_setg_errno(err, errno, "can't access fsfreeze hook '%s'", hook);
+ return;
+ }
+
+ slog("executing fsfreeze hook with arg '%s'", arg_str);
+ pid = fork();
+ if (pid == 0) {
+ setsid();
+ reopen_fd_to_null(0);
+ reopen_fd_to_null(1);
+ reopen_fd_to_null(2);
+
+ execle(hook, hook, arg_str, NULL, environ);
+ _exit(EXIT_FAILURE);
+ } else if (pid < 0) {
+ error_setg_errno(err, errno, "failed to create child process");
+ return;
+ }
+
+ ga_wait_child(pid, &status, &local_err);
+ if (error_is_set(&local_err)) {
+ error_propagate(err, local_err);
+ return;
+ }
+
+ if (!WIFEXITED(status)) {
+ error_setg(err, "fsfreeze hook has terminated abnormally");
+ return;
+ }
+
+ status = WEXITSTATUS(status);
+ if (status) {
+ error_setg(err, "fsfreeze hook has failed with status %d", status);
+ return;
+ }
+}
+
/*
* Return status of freeze/thaw
*/
@@ -436,6 +496,12 @@ int64_t qmp_guest_fsfreeze_freeze(Error **err)
slog("guest-fsfreeze called");
+ execute_fsfreeze_hook(FSFREEZE_HOOK_FREEZE, &local_err);
+ if (error_is_set(&local_err)) {
+ error_propagate(err, local_err);
+ return -1;
+ }
+
QTAILQ_INIT(&mounts);
build_fs_mount_list(&mounts, &local_err);
if (error_is_set(&local_err)) {
@@ -537,6 +603,9 @@ int64_t qmp_guest_fsfreeze_thaw(Error **err)
ga_unset_frozen(ga_state);
free_fs_mount_list(&mounts);
+
+ execute_fsfreeze_hook(FSFREEZE_HOOK_THAW, err);
+
return i;
}
diff --git a/qga/guest-agent-core.h b/qga/guest-agent-core.h
index 8934163..3354598 100644
--- a/qga/guest-agent-core.h
+++ b/qga/guest-agent-core.h
@@ -34,6 +34,7 @@ void ga_set_response_delimited(GAState *s);
bool ga_is_frozen(GAState *s);
void ga_set_frozen(GAState *s);
void ga_unset_frozen(GAState *s);
+const char *ga_fsfreeze_hook(GAState *s);
#ifndef _WIN32
void reopen_fd_to_null(int fd);
diff --git a/qga/main.c b/qga/main.c
index ba5fa1c..a9b968c 100644
--- a/qga/main.c
+++ b/qga/main.c
@@ -34,6 +34,12 @@
#include "qga/service-win32.h"
#include <windows.h>
#endif
+#ifdef __linux__
+#include <linux/fs.h>
+#ifdef FIFREEZE
+#define CONFIG_FSFREEZE
+#endif
+#endif
#ifndef _WIN32
#define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
@@ -42,6 +48,9 @@
#endif
#define QGA_STATEDIR_DEFAULT CONFIG_QEMU_LOCALSTATEDIR "/run"
#define QGA_PIDFILE_DEFAULT QGA_STATEDIR_DEFAULT "/qemu-ga.pid"
+#ifdef CONFIG_FSFREEZE
+#define QGA_FSFREEZE_HOOK_DEFAULT CONFIG_QEMU_CONFDIR "/fsfreeze-hook"
+#endif
#define QGA_SENTINEL_BYTE 0xFF
struct GAState {
@@ -64,6 +73,9 @@ struct GAState {
const char *log_filepath;
const char *pid_filepath;
} deferred_options;
+#ifdef CONFIG_FSFREEZE
+ const char *fsfreeze_hook;
+#endif
};
struct GAState *ga_state;
@@ -153,6 +165,16 @@ static void usage(const char *cmd)
" %s)\n"
" -l, --logfile set logfile path, logs to stderr by default\n"
" -f, --pidfile specify pidfile (default is %s)\n"
+#ifdef CONFIG_FSFREEZE
+" -F, --fsfreeze-hook\n"
+" enable fsfreeze hook. Accepts an optional argument that\n"
+" specifies script to run on freeze/thaw. Script will be\n"
+" called with 'freeze'/'thaw' arguments accordingly.\n"
+" (default is %s)\n"
+" If using -F with an argument, do not follow -F with a\n"
+" space.\n"
+" (for example: -F/var/run/fsfreezehook.sh)\n"
+#endif
" -t, --statedir specify dir to store state information (absolute paths\n"
" only, default is %s)\n"
" -v, --verbose log extra debugging information\n"
@@ -167,6 +189,9 @@ static void usage(const char *cmd)
"\n"
"Report bugs to <mdroth@linux.vnet.ibm.com>\n"
, cmd, QEMU_VERSION, QGA_VIRTIO_PATH_DEFAULT, QGA_PIDFILE_DEFAULT,
+#ifdef CONFIG_FSFREEZE
+ QGA_FSFREEZE_HOOK_DEFAULT,
+#endif
QGA_STATEDIR_DEFAULT);
}
@@ -401,6 +426,13 @@ void ga_unset_frozen(GAState *s)
}
}
+#ifdef CONFIG_FSFREEZE
+const char *ga_fsfreeze_hook(GAState *s)
+{
+ return s->fsfreeze_hook;
+}
+#endif
+
static void become_daemon(const char *pidfile)
{
#ifndef _WIN32
@@ -678,10 +710,13 @@ VOID WINAPI service_main(DWORD argc, TCHAR *argv[])
int main(int argc, char **argv)
{
- const char *sopt = "hVvdm:p:l:f:b:s:t:";
+ const char *sopt = "hVvdm:p:l:f:F::b:s:t:";
const char *method = NULL, *path = NULL;
const char *log_filepath = NULL;
const char *pid_filepath = QGA_PIDFILE_DEFAULT;
+#ifdef CONFIG_FSFREEZE
+ const char *fsfreeze_hook = NULL;
+#endif
const char *state_dir = QGA_STATEDIR_DEFAULT;
#ifdef _WIN32
const char *service = NULL;
@@ -691,6 +726,9 @@ int main(int argc, char **argv)
{ "version", 0, NULL, 'V' },
{ "logfile", 1, NULL, 'l' },
{ "pidfile", 1, NULL, 'f' },
+#ifdef CONFIG_FSFREEZE
+ { "fsfreeze-hook", 2, NULL, 'F' },
+#endif
{ "verbose", 0, NULL, 'v' },
{ "method", 1, NULL, 'm' },
{ "path", 1, NULL, 'p' },
@@ -723,6 +761,11 @@ int main(int argc, char **argv)
case 'f':
pid_filepath = optarg;
break;
+#ifdef CONFIG_FSFREEZE
+ case 'F':
+ fsfreeze_hook = optarg ? optarg : QGA_FSFREEZE_HOOK_DEFAULT;
+ break;
+#endif
case 't':
state_dir = optarg;
break;
@@ -786,6 +829,9 @@ int main(int argc, char **argv)
s = g_malloc0(sizeof(GAState));
s->log_level = log_level;
s->log_file = stderr;
+#ifdef CONFIG_FSFREEZE
+ s->fsfreeze_hook = fsfreeze_hook;
+#endif
g_log_set_default_handler(ga_log, s);
g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
ga_enable_logging(s);