Re: [Qemu-devel] [PATCH 34/41] migration: use QEMUFile for migration channel lifetime

[Orit Wasserman]

On 02/15/2013 07:47 PM, Paolo Bonzini wrote:
> As a start, use QEMUFile to store the destination and close it.
> qemu_get_fd gets a file descriptor that will be used by the write
> callbacks.
> 
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  include/migration/migration.h |    7 ++++---
>  migration-exec.c              |   21 ++-------------------
>  migration-fd.c                |   35 +++--------------------------------
>  migration-tcp.c               |   19 +++----------------
>  migration-unix.c              |   19 +++----------------
>  migration.c                   |    8 +++++---
>  savevm.c                      |    1 +
>  7 files changed, 21 insertions(+), 89 deletions(-)
> 
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 172ef95..cf3e81c 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -38,12 +38,13 @@ struct MigrationState
>      QEMUBH *cleanup_bh;
>  
>      QEMUFile *file;
> +    QEMUFile *migration_file;
> +
>      int fd;
> -    int state;
>      int (*get_error)(MigrationState *s);
> -    int (*close)(MigrationState *s);
>      int (*write)(MigrationState *s, const void *buff, size_t size);
> -    void *opaque;
> +
> +    int state;
>      MigrationParams params;
>      int64_t total_time;
>      int64_t downtime;
> diff --git a/migration-exec.c b/migration-exec.c
> index a2b5f8d..8c3f720 100644
> --- a/migration-exec.c
> +++ b/migration-exec.c
> @@ -43,33 +43,16 @@ static int file_write(MigrationState *s, const void * 
> buf, size_t size)
>      return write(s->fd, buf, size);
>  }
>  
> -static int exec_close(MigrationState *s)
> -{
> -    int ret = 0;
> -    DPRINTF("exec_close\n");
> -    ret = qemu_fclose(s->opaque);
> -    s->opaque = NULL;
> -    s->fd = -1;
> -    return ret;
> -}
> -
>  void exec_start_outgoing_migration(MigrationState *s, const char *command, 
> Error **errp)
>  {
> -    QEMUFile *f;
> -    f = qemu_popen_cmd(command, "w");
> -    if (f == NULL) {
> +    s->migration_file = qemu_popen_cmd(command, "w");
> +    if (s->migration_file == NULL) {
>          error_setg_errno(errp, errno, "failed to popen the migration 
> target");
>          return;
>      }
>  
> -    s->opaque = f;
> -    s->fd = qemu_get_fd(f);
> -    assert(s->fd != -1);
> -
> -    s->close = exec_close;
>      s->get_error = file_errno;
>      s->write = file_write;
> -
>      migrate_fd_connect(s);
>  }
>  
> diff --git a/migration-fd.c b/migration-fd.c
> index a99e0e3..4636457 100644
> --- a/migration-fd.c
> +++ b/migration-fd.c
> @@ -40,45 +40,16 @@ static int fd_write(MigrationState *s, const void * buf, 
> size_t size)
>      return write(s->fd, buf, size);
>  }
>  
> -static int fd_close(MigrationState *s)
> -{
> -    struct stat st;
> -    int ret;
> -
> -    DPRINTF("fd_close\n");
> -    ret = fstat(s->fd, &st);
> -    if (ret == 0 && S_ISREG(st.st_mode)) {
> -        /*
> -         * If the file handle is a regular file make sure the
> -         * data is flushed to disk before signaling success.
> -         */
> -        ret = fsync(s->fd);
> -        if (ret != 0) {
> -            ret = -errno;
> -            perror("migration-fd: fsync");
> -            return ret;
> -        }
> -    }
> -    ret = close(s->fd);
> -    s->fd = -1;
> -    if (ret != 0) {
> -        ret = -errno;
> -        perror("migration-fd: close");
> -    }
> -    return ret;
> -}
> -
>  void fd_start_outgoing_migration(MigrationState *s, const char *fdname, 
> Error **errp)
>  {
> -    s->fd = monitor_get_fd(cur_mon, fdname, errp);
> -    if (s->fd == -1) {
> +    int fd = monitor_get_fd(cur_mon, fdname, errp);
> +    if (fd == -1) {
>          return;
>      }
> +    s->migration_file = qemu_fdopen(fd, "wb");
>  
>      s->get_error = fd_errno;
>      s->write = fd_write;
> -    s->close = fd_close;
> -
>      migrate_fd_connect(s);
>  }
>  
> diff --git a/migration-tcp.c b/migration-tcp.c
> index 7d975b5..1e8e004 100644
> --- a/migration-tcp.c
> +++ b/migration-tcp.c
> @@ -39,28 +39,17 @@ static int socket_write(MigrationState *s, const void * 
> buf, size_t size)
>      return send(s->fd, buf, size, 0);
>  }
>  
> -static int tcp_close(MigrationState *s)
> -{
> -    int r = 0;
> -    DPRINTF("tcp_close\n");
> -    if (closesocket(s->fd) < 0) {
> -        r = -socket_error();
> -    }
> -    return r;
> -}
> -
>  static void tcp_wait_for_connect(int fd, void *opaque)
>  {
>      MigrationState *s = opaque;
>  
>      if (fd < 0) {
>          DPRINTF("migrate connect error\n");
> -        s->fd = -1;
> +        s->migration_file = NULL;
>          migrate_fd_error(s);
>      } else {
>          DPRINTF("migrate connect success\n");
> -        s->fd = fd;
> -        socket_set_block(s->fd);
> +        s->migration_file = qemu_fopen_socket(fd, "wb");
>          migrate_fd_connect(s);
>      }
>  }
> @@ -69,9 +58,7 @@ void tcp_start_outgoing_migration(MigrationState *s, const 
> char *host_port, Erro
>  {
>      s->get_error = socket_errno;
>      s->write = socket_write;
> -    s->close = tcp_close;
> -
> -    s->fd = inet_nonblocking_connect(host_port, tcp_wait_for_connect, s, 
> errp);
> +    inet_nonblocking_connect(host_port, tcp_wait_for_connect, s, errp);
>  }
>  
>  static void tcp_accept_incoming_migration(void *opaque)
> diff --git a/migration-unix.c b/migration-unix.c
> index 4693b43..11917f4 100644
> --- a/migration-unix.c
> +++ b/migration-unix.c
> @@ -39,28 +39,17 @@ static int unix_write(MigrationState *s, const void * 
> buf, size_t size)
>      return write(s->fd, buf, size);
>  }
>  
> -static int unix_close(MigrationState *s)
> -{
> -    int r = 0;
> -    DPRINTF("unix_close\n");
> -    if (close(s->fd) < 0) {
> -        r = -errno;
> -    }
> -    return r;
> -}
> -
>  static void unix_wait_for_connect(int fd, void *opaque)
>  {
>      MigrationState *s = opaque;
>  
>      if (fd < 0) {
>          DPRINTF("migrate connect error\n");
> -        s->fd = -1;
> +        s->migration_file = NULL;
>          migrate_fd_error(s);
>      } else {
>          DPRINTF("migrate connect success\n");
> -        s->fd = fd;
> -        socket_set_block(s->fd);
> +        s->migration_file = qemu_fopen_socket(fd, "wb");
>          migrate_fd_connect(s);
>      }
>  }
> @@ -69,9 +58,7 @@ void unix_start_outgoing_migration(MigrationState *s, const 
> char *path, Error **
>  {
>      s->get_error = unix_errno;
>      s->write = unix_write;
> -    s->close = unix_close;
> -
> -    s->fd = unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
> +    unix_nonblocking_connect(path, unix_wait_for_connect, s, errp);
>  }
>  
>  static void unix_accept_incoming_migration(void *opaque)
> diff --git a/migration.c b/migration.c
> index 8d35af5..9cffdd4 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -273,7 +273,7 @@ static void migrate_fd_cleanup(void *opaque)
>          s->file = NULL;
>      }
>  
> -    assert(s->fd == -1);
> +    assert(s->migration_file == NULL);
>      assert(s->state != MIG_STATE_ACTIVE);
>  
>      if (s->state != MIG_STATE_COMPLETED) {
> @@ -320,8 +320,9 @@ static void migrate_fd_cancel(MigrationState *s)
>  int migrate_fd_close(MigrationState *s)
>  {
>      int rc = 0;
> -    if (s->fd != -1) {
> -        rc = s->close(s);
> +    if (s->migration_file != NULL) {
> +        rc = qemu_fclose(s->migration_file);
> +        s->migration_file = NULL;
>          s->fd = -1;
>      }
>      return rc;
> @@ -694,6 +695,7 @@ void migrate_fd_connect(MigrationState *s)
>      s->xfer_limit = s->bandwidth_limit / XFER_LIMIT_RATIO;
>  
>      s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
> +    s->fd = qemu_get_fd(s->migration_file);
>      s->file = qemu_fopen_ops(s, &migration_file_ops);
>  
>      qemu_thread_create(&s->thread, migration_thread, s,
> diff --git a/savevm.c b/savevm.c
> index e4dc01d..f704f46 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -400,6 +400,7 @@ QEMUFile *qemu_fopen_socket(int fd, const char *mode)
>  
>      s->fd = fd;
>      if (mode[0] == 'w') {
> +        socket_set_block(s->fd);
>          s->file = qemu_fopen_ops(s, &socket_write_ops);
>      } else {
>          s->file = qemu_fopen_ops(s, &socket_read_ops);
> 
Reviewed-by: Orit Wasserman <address@hidden>