| Message ID | 1280242448-20775-1-git-send-email-miguel.filho@gmail.com |
|---|---|
| State | New |
| Headers | show |
Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: > The output generated by 'info snapshots' shows only snapshots that exist on the > block device that saves the VM state. This output can cause an user to > erroneously try to load an snapshot that is not available on all block devices. What happens when you try that? > $ qemu-img snapshot -l xxtest.qcow2 > Snapshot list: > ID TAG VM SIZE DATE VM CLOCK > 1 1.5M 2010-07-26 16:51:52 00:00:08.599 > 2 1.5M 2010-07-26 16:51:53 00:00:09.719 > 3 1.5M 2010-07-26 17:26:49 00:00:13.245 > 4 1.5M 2010-07-26 19:01:00 00:00:46.763 > > $ qemu-img snapshot -l xxtest2.qcow2 > Snapshot list: > ID TAG VM SIZE DATE VM CLOCK > 3 0 2010-07-26 17:26:49 00:00:13.245 > 4 0 2010-07-26 19:01:00 00:00:46.763 > > Current output: > $ qemu -hda xxtest.qcow2 -hdb xxtest2.qcow2 -monitor stdio -vnc :0 > QEMU 0.12.4 monitor - type 'help' for more information > (qemu) info snapshots > Snapshot devices: ide0-hd0 > Snapshot list (from ide0-hd0): > ID TAG VM SIZE DATE VM CLOCK > 1 1.5M 2010-07-26 16:51:52 00:00:08.599 > 2 1.5M 2010-07-26 16:51:53 00:00:09.719 > 3 1.5M 2010-07-26 17:26:49 00:00:13.245 > 4 1.5M 2010-07-26 19:01:00 00:00:46.763 > > Snapshots 1 and 2 do not exist on xxtest2.qcow, but they are displayed anyway. > > This patch sumarizes the output to only show fully available snapshots. > > New output: > (qemu) info snapshots > ID TAG VM SIZE DATE VM CLOCK > 3 1.5M 2010-07-26 17:26:49 00:00:13.245 > 4 1.5M 2010-07-26 19:01:00 00:00:46.763 > > Signed-off-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com> No information on "partial" snapshots. I doubt anybody will miss it. > --- > savevm.c | 65 ++++++++++++++++++++++++++++++++++++++++++------------------- > 1 files changed, 45 insertions(+), 20 deletions(-) > > diff --git a/savevm.c b/savevm.c > index 7a1de3c..be83878 100644 > --- a/savevm.c > +++ b/savevm.c > @@ -1997,37 +1997,62 @@ void do_delvm(Monitor *mon, const QDict *qdict) > > void do_info_snapshots(Monitor *mon) > { > - BlockDriverState *bs, *bs1; > - QEMUSnapshotInfo *sn_tab, *sn; > - int nb_sns, i; > + BlockDriverState *bs_vm_state, *bs; > + QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s; > + int nb_sns, i, ret, available; > + int total; > + int *available_snapshots; > char buf[256]; > > - bs = bdrv_snapshots(); > - if (!bs) { > + bs_vm_state = bdrv_snapshots(); > + if (!bs_vm_state) { > monitor_printf(mon, "No available block device supports snapshots\n"); > return; > } > - monitor_printf(mon, "Snapshot devices:"); > - bs1 = NULL; > - while ((bs1 = bdrv_next(bs1))) { > - if (bdrv_can_snapshot(bs1)) { > - if (bs == bs1) > - monitor_printf(mon, " %s", bdrv_get_device_name(bs1)); > - } > - } > - monitor_printf(mon, "\n"); > > - nb_sns = bdrv_snapshot_list(bs, &sn_tab); > + nb_sns = bdrv_snapshot_list(bs_vm_state, &sn_tab); > if (nb_sns < 0) { > monitor_printf(mon, "bdrv_snapshot_list: error %d\n", nb_sns); > return; > + } else if (nb_sns == 0) { > + monitor_printf(mon, "There is no snapshot available.\n"); > } This changes output for the "no snapshots available" case from the empty table ID TAG VM SIZE DATE VM CLOCK to There is no snapshot available. I'd prefer that as separate patch, if at all. Nitpick: I don't like "return; else". > - monitor_printf(mon, "Snapshot list (from %s):\n", > - bdrv_get_device_name(bs)); > - monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL)); > - for(i = 0; i < nb_sns; i++) { > + > + available_snapshots = qemu_mallocz(sizeof(int) * nb_sns); This can die due to the nonsensical semantics of qemu_mallocz(0). > + total = 0; > + for (i = 0; i < nb_sns; i++) { > sn = &sn_tab[i]; > - monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn)); > + available = 1; > + bs = NULL; > + > + while ((bs = bdrv_next(bs))) { > + if (bdrv_can_snapshot(bs) && bs != bs_vm_state) { > + ret = bdrv_snapshot_find(bs, sn_info, sn->id_str); > + if (ret < 0) { > + available = 0; > + break; > + } > + } > + } > + > + if (available) { > + available_snapshots[total] = i; > + total++; > + } > } > + > + if (total > 0) { > + monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL)); > + for (i = 0; i < total; i++) { > + sn = &sn_tab[available_snapshots[i]]; > + monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn)); > + } > + > + qemu_free(available_snapshots); > + > + } else { > + monitor_printf(mon, "There is no suitable snapshot available to be loaded.\n"); Where is available_snapshots freed when control flows through this point? > + } > + > qemu_free(sn_tab); > }
On Wed, Jul 28, 2010 at 12:38 PM, Markus Armbruster <armbru@redhat.com> wrote: > Miguel Di Ciurcio Filho <miguel.filho@gmail.com> writes: > >> The output generated by 'info snapshots' shows only snapshots that exist on the >> block device that saves the VM state. This output can cause an user to >> erroneously try to load an snapshot that is not available on all block devices. > > What happens when you try that? > I've sent a patch that will protect that from happening [1]. With that patch, the VM stays stopped, without it the VM keeps running with a failed bdrv_snapshot_goto(). > >> --- >> savevm.c | 65 ++++++++++++++++++++++++++++++++++++++++++------------------- >> 1 files changed, 45 insertions(+), 20 deletions(-) >> >> diff --git a/savevm.c b/savevm.c >> index 7a1de3c..be83878 100644 >> --- a/savevm.c >> +++ b/savevm.c >> @@ -1997,37 +1997,62 @@ void do_delvm(Monitor *mon, const QDict *qdict) >> >> void do_info_snapshots(Monitor *mon) >> { >> - BlockDriverState *bs, *bs1; >> - QEMUSnapshotInfo *sn_tab, *sn; >> - int nb_sns, i; >> + BlockDriverState *bs_vm_state, *bs; >> + QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s; >> + int nb_sns, i, ret, available; >> + int total; >> + int *available_snapshots; >> char buf[256]; >> >> - bs = bdrv_snapshots(); >> - if (!bs) { >> + bs_vm_state = bdrv_snapshots(); >> + if (!bs_vm_state) { >> monitor_printf(mon, "No available block device supports snapshots\n"); >> return; >> } >> - monitor_printf(mon, "Snapshot devices:"); >> - bs1 = NULL; >> - while ((bs1 = bdrv_next(bs1))) { >> - if (bdrv_can_snapshot(bs1)) { >> - if (bs == bs1) >> - monitor_printf(mon, " %s", bdrv_get_device_name(bs1)); >> - } >> - } >> - monitor_printf(mon, "\n"); >> >> - nb_sns = bdrv_snapshot_list(bs, &sn_tab); >> + nb_sns = bdrv_snapshot_list(bs_vm_state, &sn_tab); >> if (nb_sns < 0) { >> monitor_printf(mon, "bdrv_snapshot_list: error %d\n", nb_sns); >> return; >> + } else if (nb_sns == 0) { >> + monitor_printf(mon, "There is no snapshot available.\n"); >> } > > This changes output for the "no snapshots available" case from the empty > table > > ID TAG VM SIZE DATE VM CLOCK > > to > > There is no snapshot available. > > I'd prefer that as separate patch, if at all. I think a clear message saying "there is nothing" is better than an empty table. I'm already changing the output to something more reasonable, so. > > Nitpick: I don't like "return; else". > Yeah, kinda ugly. I will fix it. >> - monitor_printf(mon, "Snapshot list (from %s):\n", >> - bdrv_get_device_name(bs)); >> - monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL)); >> - for(i = 0; i < nb_sns; i++) { >> + >> + available_snapshots = qemu_mallocz(sizeof(int) * nb_sns); > > This can die due to the nonsensical semantics of qemu_mallocz(0). > Will fix that, so this code will be reached only if nb_sns > 0 and qemu_mallocz(0) will never be executed. >> + total = 0; >> + for (i = 0; i < nb_sns; i++) { >> sn = &sn_tab[i]; >> - monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn)); >> + available = 1; >> + bs = NULL; >> + >> + while ((bs = bdrv_next(bs))) { >> + if (bdrv_can_snapshot(bs) && bs != bs_vm_state) { >> + ret = bdrv_snapshot_find(bs, sn_info, sn->id_str); >> + if (ret < 0) { >> + available = 0; >> + break; >> + } >> + } >> + } >> + >> + if (available) { >> + available_snapshots[total] = i; >> + total++; >> + } >> } >> + >> + if (total > 0) { >> + monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL)); >> + for (i = 0; i < total; i++) { >> + sn = &sn_tab[available_snapshots[i]]; >> + monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn)); >> + } >> + >> + qemu_free(available_snapshots); >> + >> + } else { >> + monitor_printf(mon, "There is no suitable snapshot available to be loaded.\n"); > > Where is available_snapshots freed when control flows through this point? > Oops. I will fix that too. Thanks for the feedback. Regards, Miguel [1] http://lists.gnu.org/archive/html/qemu-devel/2010-07/msg01065.html (Kevin has applied it to this block branch)
diff --git a/savevm.c b/savevm.c index 7a1de3c..be83878 100644 --- a/savevm.c +++ b/savevm.c @@ -1997,37 +1997,62 @@ void do_delvm(Monitor *mon, const QDict *qdict) void do_info_snapshots(Monitor *mon) { - BlockDriverState *bs, *bs1; - QEMUSnapshotInfo *sn_tab, *sn; - int nb_sns, i; + BlockDriverState *bs_vm_state, *bs; + QEMUSnapshotInfo *sn_tab, *sn, s, *sn_info = &s; + int nb_sns, i, ret, available; + int total; + int *available_snapshots; char buf[256]; - bs = bdrv_snapshots(); - if (!bs) { + bs_vm_state = bdrv_snapshots(); + if (!bs_vm_state) { monitor_printf(mon, "No available block device supports snapshots\n"); return; } - monitor_printf(mon, "Snapshot devices:"); - bs1 = NULL; - while ((bs1 = bdrv_next(bs1))) { - if (bdrv_can_snapshot(bs1)) { - if (bs == bs1) - monitor_printf(mon, " %s", bdrv_get_device_name(bs1)); - } - } - monitor_printf(mon, "\n"); - nb_sns = bdrv_snapshot_list(bs, &sn_tab); + nb_sns = bdrv_snapshot_list(bs_vm_state, &sn_tab); if (nb_sns < 0) { monitor_printf(mon, "bdrv_snapshot_list: error %d\n", nb_sns); return; + } else if (nb_sns == 0) { + monitor_printf(mon, "There is no snapshot available.\n"); } - monitor_printf(mon, "Snapshot list (from %s):\n", - bdrv_get_device_name(bs)); - monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL)); - for(i = 0; i < nb_sns; i++) { + + available_snapshots = qemu_mallocz(sizeof(int) * nb_sns); + total = 0; + for (i = 0; i < nb_sns; i++) { sn = &sn_tab[i]; - monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn)); + available = 1; + bs = NULL; + + while ((bs = bdrv_next(bs))) { + if (bdrv_can_snapshot(bs) && bs != bs_vm_state) { + ret = bdrv_snapshot_find(bs, sn_info, sn->id_str); + if (ret < 0) { + available = 0; + break; + } + } + } + + if (available) { + available_snapshots[total] = i; + total++; + } } + + if (total > 0) { + monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), NULL)); + for (i = 0; i < total; i++) { + sn = &sn_tab[available_snapshots[i]]; + monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), sn)); + } + + qemu_free(available_snapshots); + + } else { + monitor_printf(mon, "There is no suitable snapshot available to be loaded.\n"); + } + qemu_free(sn_tab); }
The output generated by 'info snapshots' shows only snapshots that exist on the block device that saves the VM state. This output can cause an user to erroneously try to load an snapshot that is not available on all block devices. $ qemu-img snapshot -l xxtest.qcow2 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 1 1.5M 2010-07-26 16:51:52 00:00:08.599 2 1.5M 2010-07-26 16:51:53 00:00:09.719 3 1.5M 2010-07-26 17:26:49 00:00:13.245 4 1.5M 2010-07-26 19:01:00 00:00:46.763 $ qemu-img snapshot -l xxtest2.qcow2 Snapshot list: ID TAG VM SIZE DATE VM CLOCK 3 0 2010-07-26 17:26:49 00:00:13.245 4 0 2010-07-26 19:01:00 00:00:46.763 Current output: $ qemu -hda xxtest.qcow2 -hdb xxtest2.qcow2 -monitor stdio -vnc :0 QEMU 0.12.4 monitor - type 'help' for more information (qemu) info snapshots Snapshot devices: ide0-hd0 Snapshot list (from ide0-hd0): ID TAG VM SIZE DATE VM CLOCK 1 1.5M 2010-07-26 16:51:52 00:00:08.599 2 1.5M 2010-07-26 16:51:53 00:00:09.719 3 1.5M 2010-07-26 17:26:49 00:00:13.245 4 1.5M 2010-07-26 19:01:00 00:00:46.763 Snapshots 1 and 2 do not exist on xxtest2.qcow, but they are displayed anyway. This patch sumarizes the output to only show fully available snapshots. New output: (qemu) info snapshots ID TAG VM SIZE DATE VM CLOCK 3 1.5M 2010-07-26 17:26:49 00:00:13.245 4 1.5M 2010-07-26 19:01:00 00:00:46.763 Signed-off-by: Miguel Di Ciurcio Filho <miguel.filho@gmail.com> --- savevm.c | 65 ++++++++++++++++++++++++++++++++++++++++++------------------- 1 files changed, 45 insertions(+), 20 deletions(-)