On Tue, Jan 8, 2013 at 11:00 PM, Michael Roth <mdr...@linux.vnet.ibm.com> wrote:
> From: Tomoki Sekiyama <tomoki.sekiyama...@hitachi.com>
>
> 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...@hitachi.com>
> Reviewed-by: Luiz Capitulino <lcapitul...@redhat.com>
>
> *clarified usage in help output
>
> Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
> ---
> qga/commands-posix.c | 69
> ++++++++++++++++++++++++++++++++++++++++++++++++
> qga/guest-agent-core.h | 1 +
> qga/main.c | 48 ++++++++++++++++++++++++++++++++-
> 3 files changed, 117 insertions(+), 1 deletion(-)
>
> 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[] = {
static
> + "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 <mdr...@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);
> --
> 1.7.9.5
>
>
