vaapi-recorder: Don't loop trying to write on out of space condition

The error handling for the function that writes the encoded frame on
the disk was bogus, always assuming the buffer supplied to the encoder
was too small. That would cause a bigger buffer to be allocated and
another attempt to encode the frame was done. In the case of a failure
to write to disk (due to ENOSPC, for instance) that would cause an
endless loop.

Possibly-related-to: https://bugs.freedesktop.org/show_bug.cgi?id=69330

src/compositor-drm.c

@@ -2557,6 +2557,18 @@ planes_binding(struct weston_seat *seat, uint32_t time, uint32_t key, void *data
 }
 
 #ifdef BUILD_VAAPI_RECORDER
+static void
+recorder_destroy(struct drm_output *output)
+{
+	vaapi_recorder_destroy(output->recorder);
+	output->recorder = NULL;
+
+	output->base.disable_planes--;
+
+	wl_list_remove(&output->recorder_frame_listener.link);
+	weston_log("[libva recorder] done\n");
+}
+
 static void
 recorder_frame_notify(struct wl_listener *listener, void *data)
 {
@@ -2579,7 +2591,12 @@ recorder_frame_notify(struct wl_listener *listener, void *data)
 		return;
 	}
 
-	vaapi_recorder_frame(output->recorder, fd, output->current->stride);
+	ret = vaapi_recorder_frame(output->recorder, fd,
+				   output->current->stride);
+	if (ret < 0) {
+		weston_log("[libva recorder] aborted: %m\n");
+		recorder_destroy(output);
+	}
 }
 
 static void *
@@ -2637,13 +2654,7 @@ recorder_binding(struct weston_seat *seat, uint32_t time, uint32_t key,
 
 		weston_log("[libva recorder] initialized\n");
 	} else {
-		vaapi_recorder_destroy(output->recorder);
-		output->recorder = NULL;
-
-		output->base.disable_planes--;
-
-		wl_list_remove(&output->recorder_frame_listener.link);
-		weston_log("[libva recorder] done\n");
+		recorder_destroy(output);
 	}
 }
 #else

src/vaapi-recorder.c

@@ -50,6 +50,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <assert.h>
+#include <errno.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -93,6 +94,7 @@ struct vaapi_recorder {
 	int width, height;
 	int frame_count;
 
+	int error;
 	int destroying;
 	pthread_t worker_thread;
 	pthread_mutex_t mutex;
@@ -761,7 +763,13 @@ encoder_create_output_buffer(struct vaapi_recorder *r)
 		return VA_INVALID_ID;
 }
 
-static int
+enum output_write_status {
+	OUTPUT_WRITE_SUCCESS,
+	OUTPUT_WRITE_OVERFLOW,
+	OUTPUT_WRITE_FATAL
+};
+
+static enum output_write_status
 encoder_write_output(struct vaapi_recorder *r, VABufferID output_buf)
 {
 	VACodedBufferSegment *segment;
@@ -770,19 +778,22 @@ encoder_write_output(struct vaapi_recorder *r, VABufferID output_buf)
 
 	status = vaMapBuffer(r->va_dpy, output_buf, (void **) &segment);
 	if (status != VA_STATUS_SUCCESS)
-		return -1;
+		return OUTPUT_WRITE_FATAL;
 
 	if (segment->status & VA_CODED_BUF_STATUS_SLICE_OVERFLOW_MASK) {
 		r->encoder.output_size *= 2;
 		vaUnmapBuffer(r->va_dpy, output_buf);
-		return -1;
+		return OUTPUT_WRITE_OVERFLOW;
 	}
 
 	count = write(r->output_fd, segment->buf, segment->size);
 
 	vaUnmapBuffer(r->va_dpy, output_buf);
 
-	return count;
+	if (count < 0)
+		return OUTPUT_WRITE_FATAL;
+
+	return OUTPUT_WRITE_SUCCESS;
 }
 
 static void
@@ -792,9 +803,8 @@ encoder_encode(struct vaapi_recorder *r, VASurfaceID input)
 
 	VABufferID buffers[8];
 	int count = 0;
-
-	int slice_type;
-	int ret, i;
+	int i, slice_type;
+	enum output_write_status ret;
 
 	if ((r->frame_count % r->encoder.intra_period) == 0)
 		slice_type = SLICE_TYPE_I;
@@ -829,7 +839,10 @@ encoder_encode(struct vaapi_recorder *r, VASurfaceID input)
 		output_buf = VA_INVALID_ID;
 
 		vaDestroyBuffer(r->va_dpy, buffers[--count]);
-	} while (ret < 0);
+	} while (ret == OUTPUT_WRITE_OVERFLOW);
+
+	if (ret == OUTPUT_WRITE_FATAL)
+		r->error = errno;
 
 	for (i = 0; i < count; i++)
 		vaDestroyBuffer(r->va_dpy, buffers[i]);
@@ -1138,11 +1151,19 @@ worker_thread_function(void *data)
 	return NULL;
 }
 
-void
+int
 vaapi_recorder_frame(struct vaapi_recorder *r, int prime_fd, int stride)
 {
+	int ret = 0;
+
 	pthread_mutex_lock(&r->mutex);
 
+	if (r->error) {
+		errno = r->error;
+		ret = -1;
+		goto unlock;
+	}
+
 	/* The mutex is never released while encoding, so this point should
 	 * never be reached if input.valid is true. */
 	assert(!r->input.valid);
@@ -1152,5 +1173,8 @@ vaapi_recorder_frame(struct vaapi_recorder *r, int prime_fd, int stride)
 	r->input.valid = 1;
 	pthread_cond_signal(&r->input_cond);
 
+unlock:
 	pthread_mutex_unlock(&r->mutex);
+
+	return ret;
 }

src/vaapi-recorder.h

@@ -29,7 +29,7 @@ struct vaapi_recorder *
 vaapi_recorder_create(int drm_fd, int width, int height, const char *filename);
 void
 vaapi_recorder_destroy(struct vaapi_recorder *r);
-void
+int
 vaapi_recorder_frame(struct vaapi_recorder *r, int fd, int stride);
 
 #endif /* _VAAPI_RECORDER_H_ */