From 994ab360b3264e19fdf590178601fa1f9f6489d0 Mon Sep 17 00:00:00 2001
From: David Goulet <dgoulet@efficios.com>
Date: Tue, 11 Feb 2014 13:21:59 -0500
Subject: [PATCH] Fix: cleanup relayd on any I/O error in read subbuffer mmap

Any I/O operation that triggers an error now cleans the relayd since
there is no way we can recover from that in any cases and streams
associated to that relayd need to be cleaned up.

This commit also removes the "written" variable that is simply not
needed and was a bit confusing as a returned value.

Signed-off-by: David Goulet <dgoulet@efficios.com>
---
 src/common/consumer.c | 60 +++++++++++++++++--------------------------
 1 file changed, 23 insertions(+), 37 deletions(-)

diff --git a/src/common/consumer.c b/src/common/consumer.c
index c90954890..ffbecf716 100644
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -1457,7 +1457,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 {
 	unsigned long mmap_offset;
 	void *mmap_base;
-	ssize_t ret = 0, written = 0;
+	ssize_t ret = 0;
 	off_t orig_offset = stream->out_fd_offset;
 	/* Default is on the disk */
 	int outfd = stream->out_fd;
@@ -1481,9 +1481,9 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 	case LTTNG_CONSUMER_KERNEL:
 		mmap_base = stream->mmap_base;
 		ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
-		if (ret != 0) {
+		if (ret < 0) {
+			ret = -errno;
 			PERROR("tracer ctl get_mmap_read_offset");
-			written = -errno;
 			goto end;
 		}
 		break;
@@ -1492,13 +1492,13 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 		mmap_base = lttng_ustctl_get_mmap_base(stream);
 		if (!mmap_base) {
 			ERR("read mmap get mmap base for stream %s", stream->name);
-			written = -EPERM;
+			ret = -EPERM;
 			goto end;
 		}
 		ret = lttng_ustctl_get_mmap_read_offset(stream, &mmap_offset);
 		if (ret != 0) {
 			PERROR("tracer ctl get_mmap_read_offset");
-			written = ret;
+			ret = -EINVAL;
 			goto end;
 		}
 		break;
@@ -1522,30 +1522,20 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 		}
 
 		ret = write_relayd_stream_header(stream, netlen, padding, relayd);
-		if (ret >= 0) {
-			/* Use the returned socket. */
-			outfd = ret;
+		if (ret < 0) {
+			relayd_hang_up = 1;
+			goto write_error;
+		}
+		/* Use the returned socket. */
+		outfd = ret;
 
-			/* Write metadata stream id before payload */
-			if (stream->metadata_flag) {
-				ret = write_relayd_metadata_id(outfd, stream, relayd, padding);
-				if (ret < 0) {
-					written = ret;
-					/* Socket operation failed. We consider the relayd dead */
-					if (ret == -EPIPE || ret == -EINVAL) {
-						relayd_hang_up = 1;
-						goto write_error;
-					}
-					goto end;
-				}
-			}
-		} else {
-			/* Socket operation failed. We consider the relayd dead */
-			if (ret == -EPIPE || ret == -EINVAL) {
+		/* Write metadata stream id before payload */
+		if (stream->metadata_flag) {
+			ret = write_relayd_metadata_id(outfd, stream, relayd, padding);
+			if (ret < 0) {
 				relayd_hang_up = 1;
 				goto write_error;
 			}
-			/* Else, use the default set before which is the filesystem. */
 		}
 	} else {
 		/* No streaming, we have to set the len with the full padding */
@@ -1602,13 +1592,12 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 		 * amount written.
 		 */
 		if (ret < 0) {
-			written = -errno;
-		} else {
-			written = ret;
+			ret = -errno;
 		}
+		relayd_hang_up = 1;
 
 		/* Socket operation failed. We consider the relayd dead */
-		if (errno == EPIPE || errno == EINVAL) {
+		if (errno == EPIPE || errno == EINVAL || errno == EBADF) {
 			/*
 			 * This is possible if the fd is closed on the other side
 			 * (outfd) or any write problem. It can be verbose a bit for a
@@ -1616,16 +1605,13 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 			 * abruptly. This can happen so set this to a DBG statement.
 			 */
 			DBG("Consumer mmap write detected relayd hang up");
-			relayd_hang_up = 1;
-			goto write_error;
+		} else {
+			/* Unhandled error, print it and stop function right now. */
+			PERROR("Error in write mmap (ret %zd != len %lu)", ret, len);
 		}
-
-		/* Unhandled error, print it and stop function right now. */
-		PERROR("Error in write mmap (ret %zd != len %lu)", ret, len);
-		goto end;
+		goto write_error;
 	}
 	stream->output_written += ret;
-	written = ret;
 
 	/* This call is useless on a socket so better save a syscall. */
 	if (!relayd) {
@@ -1652,7 +1638,7 @@ end:
 	}
 
 	rcu_read_unlock();
-	return written;
+	return ret;
 }
 
 /*
-- 
2.34.1