We need to invalidate the Read Cache on the destination, otherwise we
have corruption. Easy way to reproduce it is:
- create an qcow2 images
- start qemu on destination of migration (qemu .... -incoming tcp:...)
- start qemu on source of migration and do one install.
- migrate at the end of install (when lot of disk IO has happened).
Destination of migration has a local copy of the L1/L2 tables that existed
at the beginning, before the install started. We have disk corruption at
this point. The solution (for NFS) is to just re-open the file. Operations
have to happen in this order:
- source of migration: flush()
- destination: close(file);
- destination: open(file)
it is not necesary that source of migration close the file.
Signed-off-by: Juan Quintela <quint...@redhat.com>
---
blockdev.c | 43 ++++++++++++++++++++++++++++++++++++++-----
blockdev.h | 6 ++++++
migration.c | 6 ++++++
3 files changed, 50 insertions(+), 5 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 0827bf7..a10de7a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -182,6 +182,7 @@ static void drive_uninit(DriveInfo *dinfo)
qemu_opts_del(dinfo->opts);
bdrv_delete(dinfo->bdrv);
g_free(dinfo->id);
+ g_free(dinfo->file);
QTAILQ_REMOVE(&drives, dinfo, next);
g_free(dinfo);
}
@@ -216,6 +217,37 @@ static int parse_block_error_action(const char *buf, int
is_read)
}
}
+static int drive_open(DriveInfo *dinfo)
+{
+ int res = bdrv_open(dinfo->bdrv, dinfo->file,
+ dinfo->bdrv_flags, dinfo->drv);
+
+ if (res < 0) {
+ fprintf(stderr, "qemu: could not open disk image %s: %s\n",
+ dinfo->file, strerror(errno));
+ }
+ return res;
+}
+
+int drives_reinit(void)
+{
+ DriveInfo *dinfo;
+
+ QTAILQ_FOREACH(dinfo, &drives, next) {
+ if (dinfo->opened && !bdrv_is_read_only(dinfo->bdrv)) {
+ int res;
+ bdrv_close(dinfo->bdrv);
+ res = drive_open(dinfo);
+ if (res) {
+ fprintf(stderr, "qemu: re-open of %s failed with error %d\n",
+ dinfo->file, res);
+ return res;
+ }
+ }
+ }
+ return 0;
+}
+
DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
{
const char *buf;
@@ -236,7 +268,6 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
const char *devaddr;
DriveInfo *dinfo;
int snapshot = 0;
- int ret;
translation = BIOS_ATA_TRANSLATION_AUTO;
media = MEDIA_DISK;
@@ -514,10 +545,12 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
- ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
- if (ret < 0) {
- error_report("could not open disk image %s: %s",
- file, strerror(-ret));
+ dinfo->file = g_strdup(file);
+ dinfo->bdrv_flags = bdrv_flags;
+ dinfo->drv = drv;
+ dinfo->opened = 1;
+
+ if (drive_open(dinfo) < 0) {
goto err;
}
diff --git a/blockdev.h b/blockdev.h
index 3587786..733eb72 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -38,6 +38,10 @@ struct DriveInfo {
char serial[BLOCK_SERIAL_STRLEN + 1];
QTAILQ_ENTRY(DriveInfo) next;
int refcount;
+ int opened;
+ int bdrv_flags;
+ char *file;
+ BlockDriver *drv;
};
DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit);
@@ -53,6 +57,8 @@ QemuOpts *drive_add(BlockInterfaceType type, int index, const
char *file,
const char *optstr);
DriveInfo *drive_init(QemuOpts *arg, int default_to_scsi);
+extern int drives_reinit(void);
+
/* device-hotplug */
DriveInfo *add_init_drive(const char *opts);
diff --git a/migration.c b/migration.c
index 4b17566..764b233 100644
--- a/migration.c
+++ b/migration.c
@@ -17,6 +17,7 @@
#include "buffered_file.h"
#include "sysemu.h"
#include "block.h"
+#include "blockdev.h"
#include "qemu_socket.h"
#include "block-migration.h"
#include "qmp-commands.h"
@@ -89,6 +90,11 @@ void process_incoming_migration(QEMUFile *f)
qemu_announce_self();
DPRINTF("successfully loaded vm state\n");
+ if (drives_reinit() != 0) {
+ fprintf(stderr, "reopening of drives failed\n");
+ exit(1);
+ }
+
if (autostart) {
vm_start();
} else {
--
1.7.7
