[Qemu-devel] [PATCH v8 0/2] qemu-ga: add hook to quiesce the guest on fsfreeze-freeze/thaw

[Qemu-devel] [PATCH v8 0/2] qemu-ga: add hook to quiesce the guest on fsfreeze-freeze/thaw

[Tomoki Sekiyama]

Hi,

This is version 8 of the qemu-ga fsfreeze hook patchset.

*Changes from v7: ( http://patchwork.ozlabs.org/patch/204426/ )
 1/2: Not changed.
 2/2: Moved .gitignore exception for fsfreeze-hook.d right below "*.d".
      Make fsfreeze success even if fsfreeze-hook.d doesn't exist.
      Use printf(1) instead of echo to output logs.
      Use "$MYSQL" $MYSQL_OPTS instead of $MYSQL_CMD for safety.
      Improve signal handling in flush-mysql.sh.
      Fix misspelling.

This patchset depends on Luiz Capitulino's patchset to improve error
handling, which is available at:
https://lists.gnu.org/archive/html/qemu-devel/2012-11/msg03016.html
---
Tomoki Sekiyama (2):
      qemu-ga: execute hook to quiesce the guest on fsfreeze-freeze/thaw
      qemu-ga: sample fsfreeze hooks

 .gitignore                                         |    1 
 Makefile                                           |    2 -
 qemu-ga.c                                          |   42 ++++++++++++
 qga/commands-posix.c                               |   69 ++++++++++++++++++++
 qga/guest-agent-core.h                             |    1 
 scripts/qemu-guest-agent/fsfreeze-hook             |   33 ++++++++++
 .../fsfreeze-hook.d/mysql-flush.sh.sample          |   56 ++++++++++++++++
 7 files changed, 202 insertions(+), 2 deletions(-)
 create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook
 create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample

Thanks,
-- 
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory

Re: [Qemu-devel] [PATCH v8 1/2] qemu-ga: execute hook to quiesce the guest on fsfreeze-freeze/thaw

[Tomoki Sekiyama]

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>
---
 qemu-ga.c              |   42 +++++++++++++++++++++++++++++
 qga/commands-posix.c   |   69 ++++++++++++++++++++++++++++++++++++++++++++++++
 qga/guest-agent-core.h |    1 +
 3 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/qemu-ga.c b/qemu-ga.c
index 9b59a52..53ce462 100644
--- a/qemu-ga.c
+++ b/qemu-ga.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 +165,10 @@ 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 (default is %s)\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 +183,9 @@ 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 +420,13 @@ 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 +704,13 @@ 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 +720,9 @@ 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 +755,11 @@ 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 +823,9 @@ 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);
diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 2591a3c..f7c0d9a 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 49a7abe..c6e8de0 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);

Re: [Qemu-devel] [PATCH v8 2/2] qemu-ga: sample fsfreeze hooks

[Tomoki Sekiyama]

Adds sample hook scripts for --fsfreeze-hook option of qemu-ga.
  - fsfreeze-hook : execute scripts in fsfreeze-hook.d/
  - fsfreeze-hook.d/mysql-flush.sh.sample : quiesce MySQL before snapshot

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
---
 .gitignore                                         |    1 
 Makefile                                           |    2 -
 scripts/qemu-guest-agent/fsfreeze-hook             |   33 ++++++++++++
 .../fsfreeze-hook.d/mysql-flush.sh.sample          |   56 ++++++++++++++++++++
 4 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook
 create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample

diff --git a/.gitignore b/.gitignore
index bd6ba1c..6456e9d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -68,6 +68,7 @@ fsdev/virtfs-proxy-helper.pod
 *.tp
 *.vr
 *.d
+!scripts/qemu-guest-agent/fsfreeze-hook.d
 *.o
 *.lo
 *.la
diff --git a/Makefile b/Makefile
index 9ecbcbb..466dcd7 100644
--- a/Makefile
+++ b/Makefile
@@ -248,7 +248,7 @@ clean:
 # avoid old build problems by removing potentially incorrect old files
 	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
 	rm -f qemu-options.def
-	find . -name '*.[od]' -exec rm -f {} +
+	find . -name '*.[od]' -type f -exec rm -f {} +
 	rm -f *.a *.lo $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
 	rm -Rf .libs
 	rm -f qemu-img-cmds.h
diff --git a/scripts/qemu-guest-agent/fsfreeze-hook b/scripts/qemu-guest-agent/fsfreeze-hook
new file mode 100755
index 0000000..c27b29f
--- /dev/null
+++ b/scripts/qemu-guest-agent/fsfreeze-hook
@@ -0,0 +1,33 @@
+#!/bin/sh
+
+# This script is executed when a guest agent receives fsfreeze-freeze and
+# fsfreeze-thaw command, if it is specified in --fsfreeze-hook (-F)
+# option of qemu-ga or placed in default path (/etc/qemu/fsfreeze-hook).
+# When the agent receives fsfreeze-freeze request, this script is issued with
+# "freeze" argument before the filesystem is frozen. And for fsfreeze-thaw
+# request, it is issued with "thaw" argument after filesystem is thawed.
+
+LOGFILE=/var/log/qga-fsfreeze-hook.log
+FSFREEZE_D=$(dirname -- "$0")/fsfreeze-hook.d
+
+# Check whether file $1 is a backup or rpm-generated file and should be ignored
+is_ignored_file() {
+    case "$1" in
+        *~ | *.bak | *.orig | *.rpmnew | *.rpmorig | *.rpmsave | *.sample)
+            return 0 ;;
+    esac
+    return 1
+}
+
+# Iterate executables in directory "fsfreeze-hook.d" with the specified args
+[ ! -d "$FSFREEZE_D" ] && exit 0
+for file in "$FSFREEZE_D"/* ; do
+    is_ignored_file "$file" && continue
+    [ -x "$file" ] || continue
+    printf "$(date): execute $file $@\n" >>$LOGFILE
+    "$file" "$@" >>$LOGFILE 2>&1
+    STATUS=$?
+    printf "$(date): $file finished with status=$STATUS\n" >>$LOGFILE
+done
+
+exit 0
diff --git a/scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample b/scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
new file mode 100755
index 0000000..2b4fa3a
--- /dev/null
+++ b/scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+# Flush MySQL tables to the disk before the filesystem is frozen.
+# At the same time, this keeps a read lock in order to avoid write accesses
+# from the other clients until the filesystem is thawed.
+
+MYSQL="/usr/bin/mysql"
+MYSQL_OPTS="-uroot" #"-prootpassword"
+FIFO=/var/run/mysql-flush.fifo
+
+# Check mysql is installed and the server running
+[ -x "$MYSQL" ] && "$MYSQL" $MYSQL_OPTS < /dev/null || exit 0
+
+flush_and_wait() {
+    printf "FLUSH TABLES WITH READ LOCK \\G\n"
+    trap 'printf "$(date): $0 is killed\n">&2' HUP INT QUIT ALRM TERM
+    read < $FIFO
+    printf "UNLOCK TABLES \\G\n"
+    rm -f $FIFO
+}
+
+case "$1" in
+    freeze)
+        mkfifo $FIFO || exit 1
+        flush_and_wait | "$MYSQL" $MYSQL_OPTS &
+        # wait until every block is flushed
+        while [ "$(echo 'SHOW STATUS LIKE "Key_blocks_not_flushed"' |\
+                 "$MYSQL" $MYSQL_OPTS | tail -1 | cut -f 2)" -gt 0 ]; do
+            sleep 1
+        done
+        # for InnoDB, wait until every log is flushed
+        INNODB_STATUS=$(mktemp /tmp/mysql-flush.XXXXXX)
+        [ $? -ne 0 ] && exit 2
+        trap "rm -f $INNODB_STATUS; exit 1" HUP INT QUIT ALRM TERM
+        while :; do
+            printf "SHOW ENGINE INNODB STATUS \\G" |\
+                "$MYSQL" $MYSQL_OPTS > $INNODB_STATUS
+            LOG_CURRENT=$(grep 'Log sequence number' $INNODB_STATUS |\
+                          tr -s ' ' | cut -d' ' -f4)
+            LOG_FLUSHED=$(grep 'Log flushed up to' $INNODB_STATUS |\
+                          tr -s ' ' | cut -d' ' -f5)
+            [ "$LOG_CURRENT" = "$LOG_FLUSHED" ] && break
+            sleep 1
+        done
+        rm -f $INNODB_STATUS
+        ;;
+
+    thaw)
+        [ ! -p $FIFO ] && exit 1
+        echo > $FIFO
+        ;;
+
+    *)
+        exit 1
+        ;;
+esac

Re: [Qemu-devel] [PATCH v8 2/2] qemu-ga: sample fsfreeze hooks

[Luiz Capitulino]

On Wed, 12 Dec 2012 12:55:57 +0900
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> wrote:

> Adds sample hook scripts for --fsfreeze-hook option of qemu-ga.
>   - fsfreeze-hook : execute scripts in fsfreeze-hook.d/
>   - fsfreeze-hook.d/mysql-flush.sh.sample : quiesce MySQL before snapshot
> 
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>

Looks good to me:

Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>

> ---
>  .gitignore                                         |    1 
>  Makefile                                           |    2 -
>  scripts/qemu-guest-agent/fsfreeze-hook             |   33 ++++++++++++
>  .../fsfreeze-hook.d/mysql-flush.sh.sample          |   56 ++++++++++++++++++++
>  4 files changed, 91 insertions(+), 1 deletion(-)
>  create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook
>  create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
> 
> diff --git a/.gitignore b/.gitignore
> index bd6ba1c..6456e9d 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -68,6 +68,7 @@ fsdev/virtfs-proxy-helper.pod
>  *.tp
>  *.vr
>  *.d
> +!scripts/qemu-guest-agent/fsfreeze-hook.d
>  *.o
>  *.lo
>  *.la
> diff --git a/Makefile b/Makefile
> index 9ecbcbb..466dcd7 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -248,7 +248,7 @@ clean:
>  # avoid old build problems by removing potentially incorrect old files
>  	rm -f config.mak op-i386.h opc-i386.h gen-op-i386.h op-arm.h opc-arm.h gen-op-arm.h
>  	rm -f qemu-options.def
> -	find . -name '*.[od]' -exec rm -f {} +
> +	find . -name '*.[od]' -type f -exec rm -f {} +
>  	rm -f *.a *.lo $(TOOLS) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~
>  	rm -Rf .libs
>  	rm -f qemu-img-cmds.h
> diff --git a/scripts/qemu-guest-agent/fsfreeze-hook b/scripts/qemu-guest-agent/fsfreeze-hook
> new file mode 100755
> index 0000000..c27b29f
> --- /dev/null
> +++ b/scripts/qemu-guest-agent/fsfreeze-hook
> @@ -0,0 +1,33 @@
> +#!/bin/sh
> +
> +# This script is executed when a guest agent receives fsfreeze-freeze and
> +# fsfreeze-thaw command, if it is specified in --fsfreeze-hook (-F)
> +# option of qemu-ga or placed in default path (/etc/qemu/fsfreeze-hook).
> +# When the agent receives fsfreeze-freeze request, this script is issued with
> +# "freeze" argument before the filesystem is frozen. And for fsfreeze-thaw
> +# request, it is issued with "thaw" argument after filesystem is thawed.
> +
> +LOGFILE=/var/log/qga-fsfreeze-hook.log
> +FSFREEZE_D=$(dirname -- "$0")/fsfreeze-hook.d
> +
> +# Check whether file $1 is a backup or rpm-generated file and should be ignored
> +is_ignored_file() {
> +    case "$1" in
> +        *~ | *.bak | *.orig | *.rpmnew | *.rpmorig | *.rpmsave | *.sample)
> +            return 0 ;;
> +    esac
> +    return 1
> +}
> +
> +# Iterate executables in directory "fsfreeze-hook.d" with the specified args
> +[ ! -d "$FSFREEZE_D" ] && exit 0
> +for file in "$FSFREEZE_D"/* ; do
> +    is_ignored_file "$file" && continue
> +    [ -x "$file" ] || continue
> +    printf "$(date): execute $file $@\n" >>$LOGFILE
> +    "$file" "$@" >>$LOGFILE 2>&1
> +    STATUS=$?
> +    printf "$(date): $file finished with status=$STATUS\n" >>$LOGFILE
> +done
> +
> +exit 0
> diff --git a/scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample b/scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
> new file mode 100755
> index 0000000..2b4fa3a
> --- /dev/null
> +++ b/scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
> @@ -0,0 +1,56 @@
> +#!/bin/sh
> +
> +# Flush MySQL tables to the disk before the filesystem is frozen.
> +# At the same time, this keeps a read lock in order to avoid write accesses
> +# from the other clients until the filesystem is thawed.
> +
> +MYSQL="/usr/bin/mysql"
> +MYSQL_OPTS="-uroot" #"-prootpassword"
> +FIFO=/var/run/mysql-flush.fifo
> +
> +# Check mysql is installed and the server running
> +[ -x "$MYSQL" ] && "$MYSQL" $MYSQL_OPTS < /dev/null || exit 0
> +
> +flush_and_wait() {
> +    printf "FLUSH TABLES WITH READ LOCK \\G\n"
> +    trap 'printf "$(date): $0 is killed\n">&2' HUP INT QUIT ALRM TERM
> +    read < $FIFO
> +    printf "UNLOCK TABLES \\G\n"
> +    rm -f $FIFO
> +}
> +
> +case "$1" in
> +    freeze)
> +        mkfifo $FIFO || exit 1
> +        flush_and_wait | "$MYSQL" $MYSQL_OPTS &
> +        # wait until every block is flushed
> +        while [ "$(echo 'SHOW STATUS LIKE "Key_blocks_not_flushed"' |\
> +                 "$MYSQL" $MYSQL_OPTS | tail -1 | cut -f 2)" -gt 0 ]; do
> +            sleep 1
> +        done
> +        # for InnoDB, wait until every log is flushed
> +        INNODB_STATUS=$(mktemp /tmp/mysql-flush.XXXXXX)
> +        [ $? -ne 0 ] && exit 2
> +        trap "rm -f $INNODB_STATUS; exit 1" HUP INT QUIT ALRM TERM
> +        while :; do
> +            printf "SHOW ENGINE INNODB STATUS \\G" |\
> +                "$MYSQL" $MYSQL_OPTS > $INNODB_STATUS
> +            LOG_CURRENT=$(grep 'Log sequence number' $INNODB_STATUS |\
> +                          tr -s ' ' | cut -d' ' -f4)
> +            LOG_FLUSHED=$(grep 'Log flushed up to' $INNODB_STATUS |\
> +                          tr -s ' ' | cut -d' ' -f5)
> +            [ "$LOG_CURRENT" = "$LOG_FLUSHED" ] && break
> +            sleep 1
> +        done
> +        rm -f $INNODB_STATUS
> +        ;;
> +
> +    thaw)
> +        [ ! -p $FIFO ] && exit 1
> +        echo > $FIFO
> +        ;;
> +
> +    *)
> +        exit 1
> +        ;;
> +esac
> 

Re: [Qemu-devel] [PATCH v8 0/2] qemu-ga: add hook to quiesce the guest on fsfreeze-freeze/thaw

[mdroth]

On Wed, Dec 12, 2012 at 12:55:47PM +0900, Tomoki Sekiyama wrote:
> Hi,
> 
> This is version 8 of the qemu-ga fsfreeze hook patchset.

Thanks, applied to qga branch with some minor clarifications for the
help output.

> 
> *Changes from v7: ( http://patchwork.ozlabs.org/patch/204426/ )
>  1/2: Not changed.
>  2/2: Moved .gitignore exception for fsfreeze-hook.d right below "*.d".
>       Make fsfreeze success even if fsfreeze-hook.d doesn't exist.
>       Use printf(1) instead of echo to output logs.
>       Use "$MYSQL" $MYSQL_OPTS instead of $MYSQL_CMD for safety.
>       Improve signal handling in flush-mysql.sh.
>       Fix misspelling.
> 
> This patchset depends on Luiz Capitulino's patchset to improve error
> handling, which is available at:
> https://lists.gnu.org/archive/html/qemu-devel/2012-11/msg03016.html
> ---
> Tomoki Sekiyama (2):
>       qemu-ga: execute hook to quiesce the guest on fsfreeze-freeze/thaw
>       qemu-ga: sample fsfreeze hooks
> 
>  .gitignore                                         |    1 
>  Makefile                                           |    2 -
>  qemu-ga.c                                          |   42 ++++++++++++
>  qga/commands-posix.c                               |   69 ++++++++++++++++++++
>  qga/guest-agent-core.h                             |    1 
>  scripts/qemu-guest-agent/fsfreeze-hook             |   33 ++++++++++
>  .../fsfreeze-hook.d/mysql-flush.sh.sample          |   56 ++++++++++++++++
>  7 files changed, 202 insertions(+), 2 deletions(-)
>  create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook
>  create mode 100755 scripts/qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
> 
> Thanks,
> -- 
> Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
> Linux Technology Center
> Hitachi, Ltd., Yokohama Research Laboratory
>