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[Qemu-devel] [RFC PATCH 02/26] blkreplay: create temporary overlay for u
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [RFC PATCH 02/26] blkreplay: create temporary overlay for underlaying devices |
Date: |
Tue, 31 Oct 2017 14:06:52 +0300 |
User-agent: |
StGit/0.17.1-dirty |
From: Pavel Dovgalyuk <address@hidden>
This patch allows using '-snapshot' behavior in record/replay mode.
blkreplay layer creates temporary overlays on top of underlaying
disk images. It is needed, because creating an overlay over blkreplay
breaks the determinism.
This patch creates similar temporary overlay (when it is needed)
under the blkreplay driver. Therefore all block operations are controlled
by blkreplay.
Signed-off-by: Pavel Dovgalyuk <address@hidden>
---
block/blkreplay.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++
stubs/replay.c | 1 +
vl.c | 2 +-
3 files changed, 67 insertions(+), 1 deletion(-)
diff --git a/block/blkreplay.c b/block/blkreplay.c
index 82a88f8..c489d50 100755
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -14,12 +14,69 @@
#include "block/block_int.h"
#include "sysemu/replay.h"
#include "qapi/error.h"
+#include "qapi/qmp/qstring.h"
typedef struct Request {
Coroutine *co;
QEMUBH *bh;
} Request;
+static BlockDriverState *blkreplay_append_snapshot(BlockDriverState *bs,
+ Error **errp)
+{
+ int ret;
+ BlockDriverState *bs_snapshot;
+ int64_t total_size;
+ QemuOpts *opts = NULL;
+ char tmp_filename[PATH_MAX + 1];
+ QDict *snapshot_options = qdict_new();
+
+ /* Prepare options QDict for the overlay file */
+ qdict_put(snapshot_options, "file.driver", qstring_from_str("file"));
+ qdict_put(snapshot_options, "driver", qstring_from_str("qcow2"));
+
+ /* Create temporary file */
+ ret = get_tmp_filename(tmp_filename, PATH_MAX + 1);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not get temporary filename");
+ goto out;
+ }
+ qdict_put(snapshot_options, "file.filename",
+ qstring_from_str(tmp_filename));
+
+ /* Get the required size from the image */
+ total_size = bdrv_getlength(bs);
+ if (total_size < 0) {
+ error_setg_errno(errp, -total_size, "Could not get image size");
+ goto out;
+ }
+
+ opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, &error_abort);
+ qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort);
+ ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp);
+ qemu_opts_del(opts);
+ if (ret < 0) {
+ error_prepend(errp, "Could not create temporary overlay '%s': ",
+ tmp_filename);
+ goto out;
+ }
+
+ bs_snapshot = bdrv_open(NULL, NULL, snapshot_options,
+ BDRV_O_RDWR | BDRV_O_TEMPORARY, errp);
+ snapshot_options = NULL;
+ if (!bs_snapshot) {
+ goto out;
+ }
+
+ bdrv_append(bs_snapshot, bs, errp);
+
+ return bs_snapshot;
+
+out:
+ QDECREF(snapshot_options);
+ return NULL;
+}
+
static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
@@ -35,6 +92,14 @@ static int blkreplay_open(BlockDriverState *bs, QDict
*options, int flags,
goto fail;
}
+ /* Add temporary snapshot to preserve the image */
+ if (!replay_snapshot
+ && !blkreplay_append_snapshot(bs->file->bs, &local_err)) {
+ ret = -EINVAL;
+ error_propagate(errp, local_err);
+ goto fail;
+ }
+
ret = 0;
fail:
return ret;
diff --git a/stubs/replay.c b/stubs/replay.c
index 9c8aa48..9991ee5 100644
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -3,6 +3,7 @@
#include "sysemu/sysemu.h"
ReplayMode replay_mode;
+char *replay_snapshot;
int64_t replay_save_clock(unsigned int kind, int64_t clock)
{
diff --git a/vl.c b/vl.c
index ec29909..7aa59f0 100644
--- a/vl.c
+++ b/vl.c
@@ -4661,7 +4661,7 @@ int main(int argc, char **argv, char **envp)
qapi_free_BlockdevOptions(bdo->bdo);
g_free(bdo);
}
- if (snapshot || replay_mode != REPLAY_MODE_NONE) {
+ if (snapshot) {
qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot,
NULL, NULL);
}
- [Qemu-devel] [RFC PATCH 00/26] replay additions, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 01/26] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 02/26] blkreplay: create temporary overlay for underlaying devices,
Pavel Dovgalyuk <=
- [Qemu-devel] [RFC PATCH 03/26] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 05/26] replay: fixed replay_enable_events, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 04/26] replay: fix processing async events, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 06/26] replay: fix save/load vm for non-empty queue, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 09/26] replay: save prior value of the host clock, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 07/26] replay: added replay log format description, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 08/26] replay: make safe vmstop at record/replay, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 10/26] icount: fixed saving/restoring of icount warp timers, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 11/26] target/arm/arm-powertctl: drop BQL assertions, Pavel Dovgalyuk, 2017/10/31
- [Qemu-devel] [RFC PATCH 12/26] cpus: push BQL lock to qemu_*_wait_io_event, Pavel Dovgalyuk, 2017/10/31