Revert 17499:451ae3b8e5c8

Breaks HVM guest creation (bugzilla #1221).

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

2 files changed, 13 insertions, 64 deletions

diff --git a/tools/blktap/drivers/blktapctrl.c b/tools/blktap/drivers/blktapctrl.c
index f15c7b997d..8825e919c4 100644
--- a/tools/blktap/drivers/blktapctrl.c
+++ b/tools/blktap/drivers/blktapctrl.c
@@ -474,8 +474,9 @@ static int read_msg(int fd, int msgtype, void *ptr)
 
 }
 
-static int launch_tapdisk_provider(char **argv)
+int launch_tapdisk(char *wrctldev, char *rdctldev)
 {
+	char *argv[] = { "tapdisk", wrctldev, rdctldev, NULL };
 	pid_t child;
 	
 	if ((child = fork()) < 0)
@@ -489,9 +490,7 @@ static int launch_tapdisk_provider(char **argv)
 			    i != STDERR_FILENO)
 				close(i);
 
-		execvp(argv[0], argv);
-		DPRINTF("execvp failed: %d (%s)\n", errno, strerror(errno));
-		DPRINTF("PATH = %s\n", getenv("PATH"));
+		execvp("tapdisk", argv);
 		_exit(1);
 	} else {
 		pid_t got;
@@ -499,78 +498,28 @@ static int launch_tapdisk_provider(char **argv)
 			got = waitpid(child, NULL, 0);
 		} while (got != child);
 	}
-	return child;
-}
-
-static int launch_tapdisk(char *wrctldev, char *rdctldev)
-{
-	char *argv[] = { "tapdisk", wrctldev, rdctldev, NULL };
-
-	if (launch_tapdisk_provider(argv) < 0)
-		return -1;
-
 	return 0;
 }
 
-static int launch_tapdisk_ioemu(void)
-{
-	char *argv[] = { "tapdisk-ioemu", NULL };
-	return launch_tapdisk_provider(argv);
-}
-
-/* 
- * Connect to an ioemu based disk provider (qemu-dm or tapdisk-ioemu)
- *
- * If the domain has a device model, connect to qemu-dm through the
- * domain specific pipe. Otherwise use a single tapdisk-ioemu instance
- * which is represented by domid 0 and provides access for Dom0 and
- * all DomUs without device model.
- */
-static int connect_qemu(blkif_t *blkif, int domid)
+/* Connect to qemu-dm */
+static int connect_qemu(blkif_t *blkif)
 {
 	char *rdctldev, *wrctldev;
-
-	static int tapdisk_ioemu_pid = 0;
-	static int dom0_readfd = 0;
-	static int dom0_writefd = 0;
 	
-	if (asprintf(&rdctldev, BLKTAP_CTRL_DIR "/qemu-read-%d", domid) < 0)
+	if (asprintf(&rdctldev, BLKTAP_CTRL_DIR "/qemu-read-%d", 
+			blkif->domid) < 0)
 		return -1;
 
-	if (asprintf(&wrctldev, BLKTAP_CTRL_DIR "/qemu-write-%d", domid) < 0) {
+	if (asprintf(&wrctldev, BLKTAP_CTRL_DIR "/qemu-write-%d", 
+			blkif->domid) < 0) {
 		free(rdctldev);
 		return -1;
 	}
 
 	DPRINTF("Using qemu blktap pipe: %s\n", rdctldev);
 	
-	if (domid == 0) {
-		/*
-		 * tapdisk-ioemu exits as soon as the last image is 
-		 * disconnected. Check if it is still running.
-		 */
-		if (tapdisk_ioemu_pid == 0 || kill(tapdisk_ioemu_pid, 0)) {
-			/* No device model and tapdisk-ioemu doesn't run yet */
-			DPRINTF("Launching tapdisk-ioemu\n");
-			tapdisk_ioemu_pid = launch_tapdisk_ioemu();
-			
-			dom0_readfd = open_ctrl_socket(wrctldev);
-			dom0_writefd = open_ctrl_socket(rdctldev);
-		}
-
-		DPRINTF("Using tapdisk-ioemu connection\n");
-		blkif->fds[READ] = dom0_readfd;
-		blkif->fds[WRITE] = dom0_writefd;
-	} else if (access(rdctldev, R_OK | W_OK) == 0) {
-		/* Use existing pipe to the device model */
-		DPRINTF("Using qemu-dm connection\n");
-		blkif->fds[READ] = open_ctrl_socket(wrctldev);
-		blkif->fds[WRITE] = open_ctrl_socket(rdctldev);
-	} else {
-		/* No device model => try with tapdisk-ioemu */
-		DPRINTF("No device model\n");
-		connect_qemu(blkif, 0);
-	}
+	blkif->fds[READ] = open_ctrl_socket(wrctldev);
+	blkif->fds[WRITE] = open_ctrl_socket(rdctldev);
 	
 	free(rdctldev);
 	free(wrctldev);
@@ -650,7 +599,7 @@ int blktapctrl_new_blkif(blkif_t *blkif)
 
 		if (!exist) {
 			if (type == DISK_TYPE_IOEMU) {
-				if (connect_qemu(blkif, blkif->domid))
+				if (connect_qemu(blkif))
 					goto fail;
 			} else {
 				if (connect_tapdisk(blkif, minor))
diff --git a/tools/blktap/drivers/tapdisk.h b/tools/blktap/drivers/tapdisk.h
index c8a21827ff..77b7fd8c83 100644
--- a/tools/blktap/drivers/tapdisk.h
+++ b/tools/blktap/drivers/tapdisk.h
@@ -235,7 +235,7 @@ static disk_info_t ioemu_disk = {
 	DISK_TYPE_IOEMU,
 	"ioemu disk",
 	"ioemu",
-	1,
+	0,
 #ifdef TAPDISK
 	NULL
 #endif