* [Qemu-devel] [PATCH 0/3] block devices record/replay update
@ 2017-01-31 11:57 Pavel Dovgalyuk
2017-01-31 11:57 ` [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay Pavel Dovgalyuk
` (3 more replies)
0 siblings, 4 replies; 11+ messages in thread
From: Pavel Dovgalyuk @ 2017-01-31 11:57 UTC (permalink / raw)
To: qemu-devel; +Cc: kwolf, pbonzini, dovgaluk, qemu-block, mreitz
This set of patches includes several fixes for preserving
the state of the block device images while recording and replaying
virtual machine execution.
blkreplay driver now creates temporary overlay for underlaying devices
This patch implicitly enables '-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
with explicit '-snapshot' option breaks the determinism.
---
Pavel Dovgalyuk (3):
block: implement bdrv_snapshot_goto for blkreplay
blkreplay: create temporary overlay for underlaying devices
replay: disable default snapshot for record/replay
block/blkreplay.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++
stubs/replay.c | 1 +
vl.c | 10 +++++-
3 files changed, 93 insertions(+), 2 deletions(-)
--
Pavel Dovgalyuk
^ permalink raw reply [flat|nested] 11+ messages in thread* [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay 2017-01-31 11:57 [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk @ 2017-01-31 11:57 ` Pavel Dovgalyuk 2017-02-22 10:05 ` Kevin Wolf 2017-01-31 11:57 ` [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices Pavel Dovgalyuk ` (2 subsequent siblings) 3 siblings, 1 reply; 11+ messages in thread From: Pavel Dovgalyuk @ 2017-01-31 11:57 UTC (permalink / raw) To: qemu-devel; +Cc: kwolf, pbonzini, dovgaluk, qemu-block, mreitz This patch enables making snapshots with blkreplay used in block devices. Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> --- block/blkreplay.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/blkreplay.c b/block/blkreplay.c index a741654..8a03d62 100644 --- a/block/blkreplay.c +++ b/block/blkreplay.c @@ -130,6 +130,12 @@ static int coroutine_fn blkreplay_co_flush(BlockDriverState *bs) return ret; } +static int blkreplay_snapshot_goto(BlockDriverState *bs, + const char *snapshot_id) +{ + return bdrv_snapshot_goto(bs->file->bs, snapshot_id); +} + static BlockDriver bdrv_blkreplay = { .format_name = "blkreplay", .protocol_name = "blkreplay", @@ -145,6 +151,8 @@ static BlockDriver bdrv_blkreplay = { .bdrv_co_pwrite_zeroes = blkreplay_co_pwrite_zeroes, .bdrv_co_pdiscard = blkreplay_co_pdiscard, .bdrv_co_flush = blkreplay_co_flush, + + .bdrv_snapshot_goto = blkreplay_snapshot_goto, }; static void bdrv_blkreplay_init(void) ^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay 2017-01-31 11:57 ` [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay Pavel Dovgalyuk @ 2017-02-22 10:05 ` Kevin Wolf 2017-02-27 12:07 ` Pavel Dovgalyuk 0 siblings, 1 reply; 11+ messages in thread From: Kevin Wolf @ 2017-02-22 10:05 UTC (permalink / raw) To: Pavel Dovgalyuk; +Cc: qemu-devel, pbonzini, qemu-block, mreitz Am 31.01.2017 um 12:57 hat Pavel Dovgalyuk geschrieben: > This patch enables making snapshots with blkreplay used in > block devices. > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> Specifically, I think it avoids the blkreplay_open/close sequence. Is this what is needed to make it work? We should probably mention in the commit message the exact reason why implementing .bdrv_snapshot_goto, but not the other snapshot related callbacks, fixes things. If you confirm my assumption, I can add that while applying. Kevin ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay 2017-02-22 10:05 ` Kevin Wolf @ 2017-02-27 12:07 ` Pavel Dovgalyuk 2017-02-27 17:35 ` Kevin Wolf 0 siblings, 1 reply; 11+ messages in thread From: Pavel Dovgalyuk @ 2017-02-27 12:07 UTC (permalink / raw) To: 'Kevin Wolf', 'Pavel Dovgalyuk' Cc: qemu-devel, pbonzini, qemu-block, mreitz > From: Kevin Wolf [mailto:kwolf@redhat.com] > Am 31.01.2017 um 12:57 hat Pavel Dovgalyuk geschrieben: > > This patch enables making snapshots with blkreplay used in > > block devices. > > > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> > > Specifically, I think it avoids the blkreplay_open/close sequence. Is > this what is needed to make it work? Then I'll need to implement bdrv_open, because there is only bdrv_file_open for blkreplay now. Which way is better? > We should probably mention in the commit message the exact reason why > implementing .bdrv_snapshot_goto, but not the other snapshot related > callbacks, fixes things. If you confirm my assumption, I can add that > while applying. Pavel Dovgalyuk ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay 2017-02-27 12:07 ` Pavel Dovgalyuk @ 2017-02-27 17:35 ` Kevin Wolf 0 siblings, 0 replies; 11+ messages in thread From: Kevin Wolf @ 2017-02-27 17:35 UTC (permalink / raw) To: Pavel Dovgalyuk Cc: 'Pavel Dovgalyuk', qemu-devel, pbonzini, qemu-block, mreitz Am 27.02.2017 um 13:07 hat Pavel Dovgalyuk geschrieben: > > From: Kevin Wolf [mailto:kwolf@redhat.com] > > Am 31.01.2017 um 12:57 hat Pavel Dovgalyuk geschrieben: > > > This patch enables making snapshots with blkreplay used in > > > block devices. > > > > > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> > > > > Specifically, I think it avoids the blkreplay_open/close sequence. Is > > this what is needed to make it work? > > Then I'll need to implement bdrv_open, because there is only bdrv_file_open > for blkreplay now. > > Which way is better? I was just checking whether I understood the reason for this correctly. If I did, then I think your solution is fine and we should just make the commit message a bit more explicit. Kevin > > We should probably mention in the commit message the exact reason why > > implementing .bdrv_snapshot_goto, but not the other snapshot related > > callbacks, fixes things. If you confirm my assumption, I can add that > > while applying. > > Pavel Dovgalyuk > ^ permalink raw reply [flat|nested] 11+ messages in thread
* [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices 2017-01-31 11:57 [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk 2017-01-31 11:57 ` [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay Pavel Dovgalyuk @ 2017-01-31 11:57 ` Pavel Dovgalyuk 2017-02-22 10:24 ` Kevin Wolf 2017-01-31 11:57 ` [Qemu-devel] [PATCH 3/3] replay: disable default snapshot for record/replay Pavel Dovgalyuk 2017-02-13 5:04 ` [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk 3 siblings, 1 reply; 11+ messages in thread From: Pavel Dovgalyuk @ 2017-01-31 11:57 UTC (permalink / raw) To: qemu-devel; +Cc: kwolf, pbonzini, dovgaluk, qemu-block, mreitz 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. Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> --- block/blkreplay.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++ stubs/replay.c | 1 + vl.c | 2 + 3 files changed, 78 insertions(+), 1 deletion(-) diff --git a/block/blkreplay.c b/block/blkreplay.c index 8a03d62..172642f 100644 --- a/block/blkreplay.c +++ b/block/blkreplay.c @@ -14,12 +14,76 @@ #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) { + ret = -EINVAL; + goto out; + } + + /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will + * call bdrv_unref() on it), so in order to be able to return one, we have + * to increase bs_snapshot's refcount here */ + bdrv_ref(bs_snapshot); + bdrv_append(bs_snapshot, bs); + + return bs_snapshot; + +out: + QDECREF(snapshot_options); + return NULL; +} + static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { @@ -35,6 +99,14 @@ 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: if (ret < 0) { @@ -45,6 +117,10 @@ fail: static void blkreplay_close(BlockDriverState *bs) { + if (!replay_snapshot) { + /* Unref created snapshot file */ + bdrv_unref(bs->file->bs); + } } static int64_t blkreplay_getlength(BlockDriverState *bs) 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 0b72b12..c6fc5c9 100644 --- a/vl.c +++ b/vl.c @@ -4414,7 +4414,7 @@ int main(int argc, char **argv, char **envp) } /* open the virtual block devices */ - if (snapshot || replay_mode != REPLAY_MODE_NONE) { + if (snapshot) { qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot, NULL, NULL); } ^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices 2017-01-31 11:57 ` [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices Pavel Dovgalyuk @ 2017-02-22 10:24 ` Kevin Wolf 0 siblings, 0 replies; 11+ messages in thread From: Kevin Wolf @ 2017-02-22 10:24 UTC (permalink / raw) To: Pavel Dovgalyuk; +Cc: qemu-devel, pbonzini, qemu-block, mreitz Am 31.01.2017 um 12:57 hat Pavel Dovgalyuk geschrieben: > 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. > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> Is replacing the '-snapshot' behaviour (which was automatically enabled before this patch) with custom code what this patch really does? In other words, does it fix that the old behaviour didn't work correctly rather than adding a new feature? If so, the commit message is prone to misunderstanding, I think. > diff --git a/block/blkreplay.c b/block/blkreplay.c > index 8a03d62..172642f 100644 > --- a/block/blkreplay.c > +++ b/block/blkreplay.c > @@ -14,12 +14,76 @@ > #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")); Both of these statements fit each in a single line. > + /* 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) { > + ret = -EINVAL; The value of ret is unused, so why set it here? > + goto out; > + } > + > + /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will > + * call bdrv_unref() on it), so in order to be able to return one, we have > + * to increase bs_snapshot's refcount here */ > + bdrv_ref(bs_snapshot); > + bdrv_append(bs_snapshot, bs); Actually, your case is exactly what bdrv_append() is designed for: You don't need to return a strong reference here, the caller just checks for NULL and that's it. So: 1. bdrv_open() return a strong reference (refcount = 1) 2. You do bdrv_ref() (refcount = 2) 3. bdrv_append() takes a reference and uses it for bs->file ... 4. bdrv_close() calls blkreplay_close(), which does a bdrv_unref() (refcount = 1) 5. bdrv_close() unrefs all child nodes (refcount = 0 --> delete) You can simplify this by just not doing the extra bdrv_ref/unref (i.e. remove steps 2 and 4). The correct reference counting is already taken care of by bdrv_append() and bdrv_close(). > + return bs_snapshot; > + > +out: > + QDECREF(snapshot_options); > + return NULL; > +} Kevin ^ permalink raw reply [flat|nested] 11+ messages in thread
* [Qemu-devel] [PATCH 3/3] replay: disable default snapshot for record/replay 2017-01-31 11:57 [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk 2017-01-31 11:57 ` [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay Pavel Dovgalyuk 2017-01-31 11:57 ` [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices Pavel Dovgalyuk @ 2017-01-31 11:57 ` Pavel Dovgalyuk 2017-02-22 10:28 ` Kevin Wolf 2017-02-13 5:04 ` [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk 3 siblings, 1 reply; 11+ messages in thread From: Pavel Dovgalyuk @ 2017-01-31 11:57 UTC (permalink / raw) To: qemu-devel; +Cc: kwolf, pbonzini, dovgaluk, qemu-block, mreitz This patch disables setting '-snapshot' option on by default in record/replay mode. This is needed for creating vmstates in record and replay modes. Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> --- vl.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/vl.c b/vl.c index c6fc5c9..671fc04 100644 --- a/vl.c +++ b/vl.c @@ -3129,7 +3129,13 @@ int main(int argc, char **argv, char **envp) drive_add(IF_PFLASH, -1, optarg, PFLASH_OPTS); break; case QEMU_OPTION_snapshot: - snapshot = 1; + { + Error *blocker = NULL; + snapshot = 1; + error_setg(&blocker, QERR_REPLAY_NOT_SUPPORTED, + "-snapshot"); + replay_add_blocker(blocker); + } break; case QEMU_OPTION_hdachs: { ^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 3/3] replay: disable default snapshot for record/replay 2017-01-31 11:57 ` [Qemu-devel] [PATCH 3/3] replay: disable default snapshot for record/replay Pavel Dovgalyuk @ 2017-02-22 10:28 ` Kevin Wolf 0 siblings, 0 replies; 11+ messages in thread From: Kevin Wolf @ 2017-02-22 10:28 UTC (permalink / raw) To: Pavel Dovgalyuk; +Cc: qemu-devel, pbonzini, qemu-block, mreitz Am 31.01.2017 um 12:57 hat Pavel Dovgalyuk geschrieben: > This patch disables setting '-snapshot' option on by default > in record/replay mode. This is needed for creating vmstates in record > and replay modes. > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> Looks good the me. (Though obviously, record/replay mode really comes with a lot more restrictions for block devices that aren't checked yet. But it's a start.) Kevin ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 0/3] block devices record/replay update 2017-01-31 11:57 [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk ` (2 preceding siblings ...) 2017-01-31 11:57 ` [Qemu-devel] [PATCH 3/3] replay: disable default snapshot for record/replay Pavel Dovgalyuk @ 2017-02-13 5:04 ` Pavel Dovgalyuk 2017-02-20 5:36 ` Pavel Dovgalyuk 3 siblings, 1 reply; 11+ messages in thread From: Pavel Dovgalyuk @ 2017-02-13 5:04 UTC (permalink / raw) To: 'Pavel Dovgalyuk', qemu-devel; +Cc: kwolf, pbonzini, qemu-block, mreitz Ping? Pavel Dovgalyuk > -----Original Message----- > From: Pavel Dovgalyuk [mailto:pavel.dovgaluk@ispras.ru] > Sent: Tuesday, January 31, 2017 2:57 PM > To: qemu-devel@nongnu.org > Cc: kwolf@redhat.com; pbonzini@redhat.com; dovgaluk@ispras.ru; qemu-block@nongnu.org; > mreitz@redhat.com > Subject: [PATCH 0/3] block devices record/replay update > > This set of patches includes several fixes for preserving > the state of the block device images while recording and replaying > virtual machine execution. > > blkreplay driver now creates temporary overlay for underlaying devices > This patch implicitly enables '-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 > with explicit '-snapshot' option breaks the determinism. > > --- > > Pavel Dovgalyuk (3): > block: implement bdrv_snapshot_goto for blkreplay > blkreplay: create temporary overlay for underlaying devices > replay: disable default snapshot for record/replay > > > block/blkreplay.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > stubs/replay.c | 1 + > vl.c | 10 +++++- > 3 files changed, 93 insertions(+), 2 deletions(-) > > -- > Pavel Dovgalyuk ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Qemu-devel] [PATCH 0/3] block devices record/replay update 2017-02-13 5:04 ` [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk @ 2017-02-20 5:36 ` Pavel Dovgalyuk 0 siblings, 0 replies; 11+ messages in thread From: Pavel Dovgalyuk @ 2017-02-20 5:36 UTC (permalink / raw) To: 'Pavel Dovgalyuk', qemu-devel; +Cc: kwolf, pbonzini, qemu-block, mreitz Destination host unreachable. Ping again. Pavel Dovgalyuk > -----Original Message----- > From: Pavel Dovgalyuk [mailto:dovgaluk@ispras.ru] > Sent: Monday, February 13, 2017 8:05 AM > To: 'Pavel Dovgalyuk'; qemu-devel@nongnu.org > Cc: kwolf@redhat.com; pbonzini@redhat.com; qemu-block@nongnu.org; mreitz@redhat.com > Subject: RE: [PATCH 0/3] block devices record/replay update > > Ping? > > Pavel Dovgalyuk > > > -----Original Message----- > > From: Pavel Dovgalyuk [mailto:pavel.dovgaluk@ispras.ru] > > Sent: Tuesday, January 31, 2017 2:57 PM > > To: qemu-devel@nongnu.org > > Cc: kwolf@redhat.com; pbonzini@redhat.com; dovgaluk@ispras.ru; qemu-block@nongnu.org; > > mreitz@redhat.com > > Subject: [PATCH 0/3] block devices record/replay update > > > > This set of patches includes several fixes for preserving > > the state of the block device images while recording and replaying > > virtual machine execution. > > > > blkreplay driver now creates temporary overlay for underlaying devices > > This patch implicitly enables '-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 > > with explicit '-snapshot' option breaks the determinism. > > > > --- > > > > Pavel Dovgalyuk (3): > > block: implement bdrv_snapshot_goto for blkreplay > > blkreplay: create temporary overlay for underlaying devices > > replay: disable default snapshot for record/replay > > > > > > block/blkreplay.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > > stubs/replay.c | 1 + > > vl.c | 10 +++++- > > 3 files changed, 93 insertions(+), 2 deletions(-) > > > > -- > > Pavel Dovgalyuk ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2017-02-27 17:35 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-01-31 11:57 [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk 2017-01-31 11:57 ` [Qemu-devel] [PATCH 1/3] block: implement bdrv_snapshot_goto for blkreplay Pavel Dovgalyuk 2017-02-22 10:05 ` Kevin Wolf 2017-02-27 12:07 ` Pavel Dovgalyuk 2017-02-27 17:35 ` Kevin Wolf 2017-01-31 11:57 ` [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices Pavel Dovgalyuk 2017-02-22 10:24 ` Kevin Wolf 2017-01-31 11:57 ` [Qemu-devel] [PATCH 3/3] replay: disable default snapshot for record/replay Pavel Dovgalyuk 2017-02-22 10:28 ` Kevin Wolf 2017-02-13 5:04 ` [Qemu-devel] [PATCH 0/3] block devices record/replay update Pavel Dovgalyuk 2017-02-20 5:36 ` Pavel Dovgalyuk
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