For backwards compatibility, a legacy stream needs converting before
it can be read by the v2 stream logic.
This causes the v2 stream logic to need to juggle two parallel tasks.
check_all_finished() is introduced for the purpose of joining the
tasks in both success and error cases.
Signed-off-by: Andrew Cooper
CC: Ian Campbell
CC: Ian Jackson
CC: Wei Liu
---
v3: Simplified greatly from v2. No practical change.
---
tools/libxl/libxl_internal.h|2 ++
tools/libxl/libxl_stream_read.c | 66 ++-
2 files changed, 67 insertions(+), 1 deletion(-)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 4de7349..8afff06 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -3260,12 +3260,14 @@ struct libxl__stream_read_state {
libxl__ao *ao;
libxl__domain_create_state *dcs;
int fd;
+bool legacy;
void (*completion_callback)(libxl__egc *egc,
libxl__stream_read_state *srs,
int rc);
/* Private */
int rc;
bool running;
+libxl__conversion_helper_state chs;
/* Main stream-reading data. */
libxl__datacopier_state dc;
diff --git a/tools/libxl/libxl_stream_read.c b/tools/libxl/libxl_stream_read.c
index e70c05a..93aa479 100644
--- a/tools/libxl/libxl_stream_read.c
+++ b/tools/libxl/libxl_stream_read.c
@@ -73,6 +73,10 @@
*- stream_write_emulator()
*- stream_write_emulator_done()
*- stream_continue()
+ *
+ * Depending on the contents of the stream, there are likely to be several
+ * parallel tasks being managed. check_all_finished() is used to join all
+ * tasks in both success and error cases.
*/
/* Success/error/cleanup handling. */
@@ -80,6 +84,10 @@ static void stream_complete(libxl__egc *egc,
libxl__stream_read_state *stream, int rc);
static void stream_done(libxl__egc *egc,
libxl__stream_read_state *stream);
+static void conversion_done(libxl__egc *egc,
+libxl__conversion_helper_state *chs, int rc);
+static void check_all_finished(libxl__egc *egc,
+ libxl__stream_read_state *stream, int rc);
/* Event chain for first iteration, from _start(). */
static void stream_header_done(libxl__egc *egc,
@@ -138,17 +146,42 @@ void libxl__stream_read_init(libxl__stream_read_state
*stream)
{
FILLZERO(*stream);
LIBXL_STAILQ_INIT(&stream->record_queue);
+libxl__conversion_helper_init(&stream->chs);
}
void libxl__stream_read_start(libxl__egc *egc,
libxl__stream_read_state *stream)
{
libxl__datacopier_state *dc = &stream->dc;
+STATE_AO_GC(stream->ao);
int rc = 0;
stream->running = true;
stream->phase = SRS_PHASE_NORMAL;
+if (stream->legacy) {
+/* Convert the legacy stream. */
+libxl__conversion_helper_state *chs = &stream->chs;
+
+chs->ao = stream->ao;
+chs->legacy_fd = stream->fd;
+chs->hvm =
+(stream->dcs->guest_config->b_info.type == LIBXL_DOMAIN_TYPE_HVM);
+chs->completion_callback = conversion_done;
+
+rc = libxl__convert_legacy_stream(egc, &stream->chs);
+
+if (rc) {
+LOG(ERROR, "Failed to start the legacy stream conversion helper");
+goto err;
+}
+
+assert(stream->chs.v2_carefd);
+stream->fd = libxl__carefd_fd(stream->chs.v2_carefd);
+stream->dcs->libxc_fd = stream->fd;
+}
+/* stream->fd is now a v2 stream. */
+
dc->ao = stream->ao;
dc->readfd = stream->fd;
dc->writefd = -1;
@@ -522,6 +555,10 @@ static void stream_done(libxl__egc *egc,
if (stream->emu_carefd)
libxl__carefd_close(stream->emu_carefd);
+/* If we started a conversion helper, we took ownership of its carefd. */
+if (stream->chs.v2_carefd)
+libxl__carefd_close(stream->chs.v2_carefd);
+
/* The record queue had better be empty if the stream believes
* itself to have been successful. */
assert(LIBXL_STAILQ_EMPTY(&stream->record_queue) || stream->rc);
@@ -529,7 +566,34 @@ static void stream_done(libxl__egc *egc,
LIBXL_STAILQ_FOREACH_SAFE(rec, &stream->record_queue, entry, trec)
free_record(rec);
-stream->completion_callback(egc, stream, stream->rc);
+check_all_finished(egc, stream, stream->rc);
+}
+
+static void conversion_done(libxl__egc *egc,
+libxl__conversion_helper_state *chs, int rc)
+{
+libxl__stream_read_state *stream = CONTAINER_OF(chs, *stream, chs);
+
+check_all_finished(egc, stream, rc);
+}
+
+static void check_all_finished(libxl__egc *egc,
+ libxl__stream_read_state *stream, int rc)
+{
+STATE_AO_GC(stream->ao);
+
+if (!stream->rc && rc) {
+/* First reported failure. Tear everything down. */
+stream->rc =