From c4d2c6c6753fd2c41c3db1877c5c46613dc45510 Mon Sep 17 00:00:00 2001
From: sr
Date: Thu, 25 Jul 2013 23:44:18 +0200
Subject: Work in progress: uplink

---
 src/server/uplink.c | 44 ++++++++++++++++++++++++++++++++++----------
 1 file changed, 34 insertions(+), 10 deletions(-)

(limited to 'src/server/uplink.c')

diff --git a/src/server/uplink.c b/src/server/uplink.c
index 92cf944..0116fda 100644
--- a/src/server/uplink.c
+++ b/src/server/uplink.c
@@ -2,6 +2,7 @@
 #include "locks.h"
 #include "memlog.h"
 #include "sockhelper.h"
+#include "image.h"
 #include <pthread.h>
 #include <sys/socket.h>
 #include <string.h>
@@ -108,6 +109,7 @@ int uplink_init(dnbd3_image_t *image)
 	link->betterFd = -1;
 	link->rttTestResult = RTT_IDLE;
 	link->recvBufferLen = 0;
+	link->shutdown = FALSE;
 	spin_init( &link->lock, PTHREAD_PROCESS_PRIVATE );
 	if ( 0 != pthread_create( &(link->thread), NULL, &uplink_mainloop, (void *)(uintptr_t)link ) ) {
 		memlogf( "[ERROR] Could not start thread for new client." );
@@ -122,13 +124,21 @@ int uplink_init(dnbd3_image_t *image)
 	return FALSE;
 }
 
-void uplink_shutdown(dnbd3_connection_t *uplink)
+dnbd3_connection_t* uplink_shutdown(dnbd3_connection_t *uplink)
 {
 	assert( uplink != NULL );
-	if ( uplink->fd != -1 ) close( uplink->fd );
+	if ( uplink->shutdown ) return NULL ;
+	uplink->shutdown = TRUE;
+	if ( uplink->signal != -1 ) write( uplink->signal, uplink, 1 );
 	pthread_join( uplink->thread, NULL );
+	free( uplink );
+	return NULL ;
 }
 
+/**
+ * Uplink thread.
+ * Locks are irrelevant as this is never called from another function
+ */
 static void* uplink_mainloop(void *data)
 {
 	const int MAXEVENTS = 3;
@@ -166,7 +176,7 @@ static void* uplink_mainloop(void *data)
 			goto cleanup;
 		}
 	}
-	while ( !_shutdown ) {
+	while ( !_shutdown && !link->shutdown ) {
 		if ( link->rttTestResult == RTT_DOCHANGE ) {
 			link->rttTestResult = RTT_IDLE;
 			// The rttTest worker thread has finished our request.
@@ -193,6 +203,7 @@ static void* uplink_mainloop(void *data)
 			if ( waitTime < 1500 ) waitTime = 1500;
 		}
 		numSocks = epoll_wait( fdEpoll, events, MAXEVENTS, waitTime );
+		if ( _shutdown || link->shutdown ) break;
 		if ( numSocks < 0 ) { // Error?
 			memlogf( "[DEBUG] epoll_wait() error %d", (int)errno);
 			usleep( 10000 );
@@ -235,18 +246,22 @@ static void* uplink_mainloop(void *data)
 	return NULL ;
 }
 
+/**
+ * Receive data from uplink server and process/dispatch
+ * Locks on: link.lock, indirectly on images[].lock
+ */
 static void uplink_handle_receive(dnbd3_connection_t *link)
 {
 	dnbd3_reply_t reply;
 	int ret, i;
 	ret = recv( link->fd, &reply, sizeof reply, MSG_WAITALL );
 	if ( ret != sizeof reply ) {
-		memlogf( "[INFO] Lost connection to uplink server." );
+		memlogf( "[INFO] Lost connection to uplink server for %s", link->image->path );
 		goto error_cleanup;
 	}
 	fixup_reply( reply );
 	if ( reply.size > 9000000 ) {
-		memlogf( "[WARNING] Pure evil: Uplink server sent too much payload!" );
+		memlogf( "[WARNING] Pure evil: Uplink server sent too much payload for %s", link->image->path );
 		goto error_cleanup;
 	}
 	if ( link->recvBufferLen < reply.size ) {
@@ -258,19 +273,16 @@ static void uplink_handle_receive(dnbd3_connection_t *link)
 	while ( done < reply.size ) {
 		ret = recv( link->fd, link->recvBuffer + done, reply.size - done, 0 );
 		if ( ret <= 0 ) {
-			memlogf( "[INFO] Lost connection to uplink server" );
+			memlogf( "[INFO] Lost connection to uplink server of", link->image->path );
 			goto error_cleanup;
 		}
 		done += ret;
 	}
 	// Payload read completely
-	// 1) Write to cache file
-	assert( link->image->cacheFd != -1 );
-	// 2) Figure out which clients are interested in it
+	// 1) Figure out which clients are interested in it
 	const uint64_t start = reply.handle;
 	const uint64_t end = reply.handle + reply.size;
 	struct iovec iov[2];
-	reply.magic = dnbd3_packet_magic;
 	spin_lock( &link->lock );
 	for (i = 0; i < link->queuelen; ++i) {
 		dnbd3_queued_request_t * const req = &link->queue[i];
@@ -280,6 +292,18 @@ static void uplink_handle_receive(dnbd3_connection_t *link)
 			req->status = ULR_PROCESSING;
 		}
 	}
+	spin_unlock( &link->lock );
+	// 2) Write to cache file
+	assert( link->image->cacheFd != -1 );
+	if ( lseek( link->image->cacheFd, start, SEEK_SET ) != start ) {
+		memlogf( "[ERROR] lseek() failed when writing to cache for %s", link->image->path );
+	} else {
+		ret = (int)write( link->image->cacheFd, link->recvBuffer, reply.size );
+		if ( ret > 0 ) image_update_cachemap( link->image, start, start + ret, TRUE);
+	}
+	// 3) Send to interested clients
+	reply.magic = dnbd3_packet_magic; // !! re-using reply struct - do not read from it after here
+	spin_lock( &link->lock );
 	for (i = link->queuelen - 1; i >= 0; --i) {
 		dnbd3_queued_request_t * const req = &link->queue[i];
 		if ( req->status != ULR_PROCESSING ) continue;
-- 
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