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[Qemu-devel] [RFC PATCH v4 03/23] blkreplay: create temporary overlay fo
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [RFC PATCH v4 03/23] blkreplay: create temporary overlay for underlaying devices |
Date: |
Fri, 19 Jan 2018 11:42:59 +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 4c58bd2..2bef4d6 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 2586f25..340d085 100644
--- a/vl.c
+++ b/vl.c
@@ -4548,7 +4548,7 @@ 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 v4 00/23] replay additions, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 01/23] This patch adds a condition before overwriting exception_index fields., Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 02/23] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 03/23] blkreplay: create temporary overlay for underlaying devices,
Pavel Dovgalyuk <=
- [Qemu-devel] [RFC PATCH v4 04/23] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 05/23] replay: fix processing async events, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 06/23] replay: fixed replay_enable_events, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 07/23] replay: fix save/load vm for non-empty queue, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 08/23] replay: added replay log format description, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 09/23] replay: make safe vmstop at record/replay, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 10/23] replay: save prior value of the host clock, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 11/23] target/arm/arm-powertctl: drop BQL assertions, Pavel Dovgalyuk, 2018/01/19
- [Qemu-devel] [RFC PATCH v4 12/23] cpus: push BQL lock to qemu_*_wait_io_event, Pavel Dovgalyuk, 2018/01/19