| Message ID | 1280345424-12918-4-git-send-email-miguel.filho@gmail.com |
|---|---|
| State | New |
| Headers | show |
Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: > This patch address two issues. > > 1) When savevm is run using an previously saved snapshot id or name, it will > delete the original and create a new one, using the same id and name and not > prompting the user of what just happened. > > This behaviour is not good, IMHO. Debatable. > We add a '-f' parameter to savevm, to really force that to happen, in case the > user really wants to. Incompatible change, looks like it'll break libvirt. Doesn't mean we can't do it ever, but right now may not be the best time. Perhaps after savevm & friends are fully functional in QMP. > New behavior: > (qemu) savevm snap1 > An snapshot named 'snap1' already exists > > (qemu) savevm -f snap1 > > We do better error reporting in case '-f' is used too than before. > > 2) When savevm is run without a name or id, the name stays blank. > > This is a first step to hide the internal id, because I don't see a reason to > expose this kind of internals to the user. Huh? > The new behavior is when savevm is run without parameters a name will be > created automaticaly, so the snapshot is accessible to the user without needing > the id when loadvm is run. Aha, now it makes sense. Suggest to swap the paragraphs. > (qemu) savevm > (qemu) info snapshots > ID TAG VM SIZE DATE VM CLOCK > 1 vm-20100728134640 978K 2010-07-28 13:46:40 00:00:08.603 > > We use a name with the format 'vm-YYYYMMDDHHMMSS'. > > TODO: I have no clue on how to create a timestamp string when using Windows. > > Signed-off-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com> > --- > qemu-monitor.hx | 9 ++++--- > savevm.c | 59 ++++++++++++++++++++++++++++++++---------------------- > 2 files changed, 40 insertions(+), 28 deletions(-) > > diff --git a/qemu-monitor.hx b/qemu-monitor.hx > index 9c27b31..94e8178 100644 > --- a/qemu-monitor.hx > +++ b/qemu-monitor.hx > @@ -275,14 +275,15 @@ ETEXI > > { > .name = "savevm", > - .args_type = "name:s?", > - .params = "[tag|id]", > - .help = "save a VM snapshot. If no tag or id are provided, a new snapshot is created", > + .args_type = "force:-f,name:s?", > + .params = "[-f] [name]", > + .help = "save a VM snapshot. If no name is provided, a new one will be generated" > + "\n\t\t\t -f to overwrite an snapshot if it already exists", > .mhandler.cmd = do_savevm, > }, > > STEXI > -@item savevm [@var{tag}|@var{id}] > +@item savevm [-f] [@var{tag}] > @findex savevm > Create a snapshot of the whole virtual machine. If @var{tag} is > provided, it is used as human readable identifier. If there is already > diff --git a/savevm.c b/savevm.c > index fb38e8a..ae6f29f 100644 > --- a/savevm.c > +++ b/savevm.c > @@ -1785,7 +1785,7 @@ static int del_existing_snapshots(Monitor *mon, const char *name) > > void do_savevm(Monitor *mon, const QDict *qdict) > { > - BlockDriverState *bs, *bs1; > + BlockDriverState *bs_vm_state, *bs; These renames make the patch harder to review. > QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1; > int ret; > QEMUFile *f; > @@ -1796,7 +1796,9 @@ void do_savevm(Monitor *mon, const QDict *qdict) > #else > struct timeval tv; > #endif > + struct tm tm; > const char *name = qdict_get_try_str(qdict, "name"); > + int force = qdict_get_try_bool(qdict, "force", 0); > > /* Verify if there is a device that doesn't support snapshots and is writable */ > bs = NULL; > @@ -1813,8 +1815,8 @@ void do_savevm(Monitor *mon, const QDict *qdict) > } > } > > - bs = bdrv_snapshots(); > - if (!bs) { > + bs_vm_state = bdrv_snapshots(); > + if (!bs_vm_state) { > monitor_printf(mon, "No block device can accept snapshots\n"); > return; > } > @@ -1825,15 +1827,6 @@ void do_savevm(Monitor *mon, const QDict *qdict) > vm_stop(0); > > memset(sn, 0, sizeof(*sn)); > - if (name) { > - ret = bdrv_snapshot_find(bs, old_sn, name); > - if (ret >= 0) { > - pstrcpy(sn->name, sizeof(sn->name), old_sn->name); > - pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str); > - } else { > - pstrcpy(sn->name, sizeof(sn->name), name); > - } > - } > > /* fill auxiliary fields */ > #ifdef _WIN32 > @@ -1847,13 +1840,31 @@ void do_savevm(Monitor *mon, const QDict *qdict) > #endif > sn->vm_clock_nsec = qemu_get_clock(vm_clock); > > - /* Delete old snapshots of the same name */ > - if (name && del_existing_snapshots(mon, name) < 0) { > - goto the_end; > + if (name) { > + ret = bdrv_snapshot_find(bs_vm_state, old_sn, name); > + if (ret == 0) { > + if (force) { > + ret = del_existing_snapshots(mon, name); > + if (ret < 0) { > + monitor_printf(mon, "Error deleting snapshot '%s', error: %d\n", > + name, ret); > + goto the_end; > + } > + } else { > + monitor_printf(mon, "An snapshot named '%s' already exists\n", name); > + goto the_end; > + } > + } > + > + pstrcpy(sn->name, sizeof(sn->name), name); > + } else { > + /* TODO: handle Windows */ > + localtime_r(&tv.tv_sec, &tm); > + strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", &tm); > } > > /* save the VM state */ > - f = qemu_fopen_bdrv(bs, 1); > + f = qemu_fopen_bdrv(bs_vm_state, 1); > if (!f) { > monitor_printf(mon, "Could not open VM state file\n"); > goto the_end; > @@ -1867,23 +1878,23 @@ void do_savevm(Monitor *mon, const QDict *qdict) > } > > /* create the snapshots */ > - > - bs1 = NULL; > - while ((bs1 = bdrv_next(bs1))) { > - if (bdrv_can_snapshot(bs1)) { > + bs = NULL; > + while ((bs = bdrv_next(bs))) { > + if (bdrv_can_snapshot(bs)) { > /* Write VM state size only to the image that contains the state */ > - sn->vm_state_size = (bs == bs1 ? vm_state_size : 0); > - ret = bdrv_snapshot_create(bs1, sn); > + sn->vm_state_size = (bs_vm_state == bs ? vm_state_size : 0); > + ret = bdrv_snapshot_create(bs, sn); > if (ret < 0) { > monitor_printf(mon, "Error while creating snapshot on '%s'\n", > - bdrv_get_device_name(bs1)); > + bdrv_get_device_name(bs)); > } > } > } > > the_end: > - if (saved_vm_running) > + if (saved_vm_running) { > vm_start(); > + } I don't like style changes mixed up with functional changes in the same patch. It's fine if you have to touch the code anyway, but here you don't. > } > > int load_vmstate(const char *name)
On Wed, 28 Jul 2010 16:30:24 -0300 Miguel Di Ciurcio Filho <miguel.filho@gmail.com> wrote: > This patch address two issues. Then it should be split in two. > > 1) When savevm is run using an previously saved snapshot id or name, it will > delete the original and create a new one, using the same id and name and not > prompting the user of what just happened. > > This behaviour is not good, IMHO. > > We add a '-f' parameter to savevm, to really force that to happen, in case the > user really wants to. > > New behavior: > (qemu) savevm snap1 > An snapshot named 'snap1' already exists > > (qemu) savevm -f snap1 > > We do better error reporting in case '-f' is used too than before. > > 2) When savevm is run without a name or id, the name stays blank. > > This is a first step to hide the internal id, because I don't see a reason to > expose this kind of internals to the user. > > The new behavior is when savevm is run without parameters a name will be > created automaticaly, so the snapshot is accessible to the user without needing > the id when loadvm is run. > > (qemu) savevm > (qemu) info snapshots > ID TAG VM SIZE DATE VM CLOCK > 1 vm-20100728134640 978K 2010-07-28 13:46:40 00:00:08.603 > > We use a name with the format 'vm-YYYYMMDDHHMMSS'. > > TODO: I have no clue on how to create a timestamp string when using Windows. So, what happens on windows? Also, please, avoid making changes which are unrelated to the patch, like: > the_end: > - if (saved_vm_running) > + if (saved_vm_running) { > vm_start(); > + } > } > > int load_vmstate(const char *name)
On Fri, 30 Jul 2010 11:34:57 +0200 Markus Armbruster <armbru@redhat.com> wrote: > Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: > > > This patch address two issues. > > > > 1) When savevm is run using an previously saved snapshot id or name, it will > > delete the original and create a new one, using the same id and name and not > > prompting the user of what just happened. > > > > This behaviour is not good, IMHO. > > Debatable. Automatically destroying previously saved data without any notice seems a quite bad behavior to me. > > We add a '-f' parameter to savevm, to really force that to happen, in case the > > user really wants to. > > Incompatible change, looks like it'll break libvirt. Doesn't mean we > can't do it ever, but right now may not be the best time. Perhaps after > savevm & friends are fully functional in QMP. Chris, could you please check whether this impacts libvirt?
On Fri, Jul 30, 2010 at 10:39 AM, Luiz Capitulino <lcapitulino@redhat.com> wrote: >> >> TODO: I have no clue on how to create a timestamp string when using Windows. > > So, what happens on windows? > I've found some code in bdrv_snapshot_dump() that formats a timestamp when using Windows. I will use it as a basis. > Also, please, avoid making changes which are unrelated to the patch, like: > >> the_end: >> - if (saved_vm_running) >> + if (saved_vm_running) { >> vm_start(); >> + } >> } >> Ack. Coding style cleanups must have a separate patch :-D Regards, Miguel
Luiz Capitulino <lcapitulino@redhat.com> writes: > On Fri, 30 Jul 2010 11:34:57 +0200 > Markus Armbruster <armbru@redhat.com> wrote: > >> Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: >> >> > This patch address two issues. >> > >> > 1) When savevm is run using an previously saved snapshot id or name, it will >> > delete the original and create a new one, using the same id and name and not >> > prompting the user of what just happened. >> > >> > This behaviour is not good, IMHO. >> >> Debatable. > > Automatically destroying previously saved data without any notice seems > a quite bad behavior to me. See cp, mv ;) [...]
On Fri, 30 Jul 2010 16:43:09 +0200 Markus Armbruster <armbru@redhat.com> wrote: > Luiz Capitulino <lcapitulino@redhat.com> writes: > > > On Fri, 30 Jul 2010 11:34:57 +0200 > > Markus Armbruster <armbru@redhat.com> wrote: > > > >> Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: > >> > >> > This patch address two issues. > >> > > >> > 1) When savevm is run using an previously saved snapshot id or name, it will > >> > delete the original and create a new one, using the same id and name and not > >> > prompting the user of what just happened. > >> > > >> > This behaviour is not good, IMHO. > >> > >> Debatable. > > > > Automatically destroying previously saved data without any notice seems > > a quite bad behavior to me. > > See cp, mv ;) Nah, unrelated because the name of the command imply that. A best comparison would be lvcreate have such semantics.
On Fri, 30 Jul 2010 11:42:44 -0300 Miguel Di Ciurcio Filho <miguel.filho@gmail.com> wrote: > On Fri, Jul 30, 2010 at 10:39 AM, Luiz Capitulino > <lcapitulino@redhat.com> wrote: > >> > >> TODO: I have no clue on how to create a timestamp string when using Windows. > > > > So, what happens on windows? > > > > I've found some code in bdrv_snapshot_dump() that formats a timestamp > when using Windows. I will use it as a basis. How hard would be for you to test it, we shouldn't commit untested code.
On 07/30/10 - 10:43:01AM, Luiz Capitulino wrote: > On Fri, 30 Jul 2010 11:34:57 +0200 > Markus Armbruster <armbru@redhat.com> wrote: > > > Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: > > > > > This patch address two issues. > > > > > > 1) When savevm is run using an previously saved snapshot id or name, it will > > > delete the original and create a new one, using the same id and name and not > > > prompting the user of what just happened. > > > > > > This behaviour is not good, IMHO. > > > > Debatable. > > Automatically destroying previously saved data without any notice seems > a quite bad behavior to me. > > > > We add a '-f' parameter to savevm, to really force that to happen, in case the > > > user really wants to. > > > > Incompatible change, looks like it'll break libvirt. Doesn't mean we > > can't do it ever, but right now may not be the best time. Perhaps after > > savevm & friends are fully functional in QMP. > > Chris, could you please check whether this impacts libvirt? Sorry for the delay here. As far as libvirt is concerned, this won't break the functionality, just change the semantics. If you only ever do snapshots through libvirt, then we can never run into this situation; libvirt prevents 2 snapshots from having the same name. Today, if you do a mixture of snapshots through the monitor and snapshots through libvirt, and you name them the same, then libvirt *could* silently override the old one. After this patch, the savevm will fail (which libvirt will gracefully handle. In any case, it's a corner case that libvirt will never intentionally put itself into, so either way is fine with me. (I also tend to think that overwriting data without any notification isn't very nice, but I also understand that this is a change in semantics)
diff --git a/qemu-monitor.hx b/qemu-monitor.hx index 9c27b31..94e8178 100644 --- a/qemu-monitor.hx +++ b/qemu-monitor.hx @@ -275,14 +275,15 @@ ETEXI { .name = "savevm", - .args_type = "name:s?", - .params = "[tag|id]", - .help = "save a VM snapshot. If no tag or id are provided, a new snapshot is created", + .args_type = "force:-f,name:s?", + .params = "[-f] [name]", + .help = "save a VM snapshot. If no name is provided, a new one will be generated" + "\n\t\t\t -f to overwrite an snapshot if it already exists", .mhandler.cmd = do_savevm, }, STEXI -@item savevm [@var{tag}|@var{id}] +@item savevm [-f] [@var{tag}] @findex savevm Create a snapshot of the whole virtual machine. If @var{tag} is provided, it is used as human readable identifier. If there is already diff --git a/savevm.c b/savevm.c index fb38e8a..ae6f29f 100644 --- a/savevm.c +++ b/savevm.c @@ -1785,7 +1785,7 @@ static int del_existing_snapshots(Monitor *mon, const char *name) void do_savevm(Monitor *mon, const QDict *qdict) { - BlockDriverState *bs, *bs1; + BlockDriverState *bs_vm_state, *bs; QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1; int ret; QEMUFile *f; @@ -1796,7 +1796,9 @@ void do_savevm(Monitor *mon, const QDict *qdict) #else struct timeval tv; #endif + struct tm tm; const char *name = qdict_get_try_str(qdict, "name"); + int force = qdict_get_try_bool(qdict, "force", 0); /* Verify if there is a device that doesn't support snapshots and is writable */ bs = NULL; @@ -1813,8 +1815,8 @@ void do_savevm(Monitor *mon, const QDict *qdict) } } - bs = bdrv_snapshots(); - if (!bs) { + bs_vm_state = bdrv_snapshots(); + if (!bs_vm_state) { monitor_printf(mon, "No block device can accept snapshots\n"); return; } @@ -1825,15 +1827,6 @@ void do_savevm(Monitor *mon, const QDict *qdict) vm_stop(0); memset(sn, 0, sizeof(*sn)); - if (name) { - ret = bdrv_snapshot_find(bs, old_sn, name); - if (ret >= 0) { - pstrcpy(sn->name, sizeof(sn->name), old_sn->name); - pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str); - } else { - pstrcpy(sn->name, sizeof(sn->name), name); - } - } /* fill auxiliary fields */ #ifdef _WIN32 @@ -1847,13 +1840,31 @@ void do_savevm(Monitor *mon, const QDict *qdict) #endif sn->vm_clock_nsec = qemu_get_clock(vm_clock); - /* Delete old snapshots of the same name */ - if (name && del_existing_snapshots(mon, name) < 0) { - goto the_end; + if (name) { + ret = bdrv_snapshot_find(bs_vm_state, old_sn, name); + if (ret == 0) { + if (force) { + ret = del_existing_snapshots(mon, name); + if (ret < 0) { + monitor_printf(mon, "Error deleting snapshot '%s', error: %d\n", + name, ret); + goto the_end; + } + } else { + monitor_printf(mon, "An snapshot named '%s' already exists\n", name); + goto the_end; + } + } + + pstrcpy(sn->name, sizeof(sn->name), name); + } else { + /* TODO: handle Windows */ + localtime_r(&tv.tv_sec, &tm); + strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", &tm); } /* save the VM state */ - f = qemu_fopen_bdrv(bs, 1); + f = qemu_fopen_bdrv(bs_vm_state, 1); if (!f) { monitor_printf(mon, "Could not open VM state file\n"); goto the_end; @@ -1867,23 +1878,23 @@ void do_savevm(Monitor *mon, const QDict *qdict) } /* create the snapshots */ - - bs1 = NULL; - while ((bs1 = bdrv_next(bs1))) { - if (bdrv_can_snapshot(bs1)) { + bs = NULL; + while ((bs = bdrv_next(bs))) { + if (bdrv_can_snapshot(bs)) { /* Write VM state size only to the image that contains the state */ - sn->vm_state_size = (bs == bs1 ? vm_state_size : 0); - ret = bdrv_snapshot_create(bs1, sn); + sn->vm_state_size = (bs_vm_state == bs ? vm_state_size : 0); + ret = bdrv_snapshot_create(bs, sn); if (ret < 0) { monitor_printf(mon, "Error while creating snapshot on '%s'\n", - bdrv_get_device_name(bs1)); + bdrv_get_device_name(bs)); } } } the_end: - if (saved_vm_running) + if (saved_vm_running) { vm_start(); + } } int load_vmstate(const char *name)
This patch address two issues. 1) When savevm is run using an previously saved snapshot id or name, it will delete the original and create a new one, using the same id and name and not prompting the user of what just happened. This behaviour is not good, IMHO. We add a '-f' parameter to savevm, to really force that to happen, in case the user really wants to. New behavior: (qemu) savevm snap1 An snapshot named 'snap1' already exists (qemu) savevm -f snap1 We do better error reporting in case '-f' is used too than before. 2) When savevm is run without a name or id, the name stays blank. This is a first step to hide the internal id, because I don't see a reason to expose this kind of internals to the user. The new behavior is when savevm is run without parameters a name will be created automaticaly, so the snapshot is accessible to the user without needing the id when loadvm is run. (qemu) savevm (qemu) info snapshots ID TAG VM SIZE DATE VM CLOCK 1 vm-20100728134640 978K 2010-07-28 13:46:40 00:00:08.603 We use a name with the format 'vm-YYYYMMDDHHMMSS'. TODO: I have no clue on how to create a timestamp string when using Windows. Signed-off-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com> --- qemu-monitor.hx | 9 ++++--- savevm.c | 59 ++++++++++++++++++++++++++++++++---------------------- 2 files changed, 40 insertions(+), 28 deletions(-)