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Re: [Qemu-devel] [PATCH] migration: Fix block failure cases
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH] migration: Fix block failure cases |
Date: |
Fri, 2 Mar 2018 11:43:48 +0800 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
On Thu, Mar 01, 2018 at 03:32:19PM +0000, Dr. David Alan Gilbert wrote:
> * Peter Xu (address@hidden) wrote:
> > On Wed, Feb 28, 2018 at 04:49:37PM +0000, Dr. David Alan Gilbert (git)
> > wrote:
> > > From: "Dr. David Alan Gilbert" <address@hidden>
> > >
> > > This fixes a couple of cases where the block migration capability
> > > doesn't get cleared when a migration failed.
> > >
> > > 1) When block migration is compiled out:
> > > (qemu) migrate -d -b "exec:cat > /dev/null"
> > > QEMU compiled without old-style (blk/-b, inc/-i) block migration
> > > Use drive_mirror+NBD instead.
> > > (qemu) migrate_set_capability xbzrle off
> > > QEMU compiled without old-style (blk/-b, inc/-i) block migration
> > > Use drive_mirror+NBD instead.
> > >
> > > This corresponds to https://bugzilla.redhat.com/show_bug.cgi?id=1550022
> > >
> > > 2) When a migration with a bad protocol is tried:
> > > (qemu) migrate -d -b "foo:bah"
> > > Parameter 'uri' expects a valid migration protocol
> > > (qemu) info migrate_capabilities
> > > xbzrle: off
> > > rdma-pin-all: off
> > > auto-converge: off
> > > zero-blocks: off
> > > compress: off
> > > events: off
> > > postcopy-ram: off
> > > x-colo: off
> > > release-ram: off
> > > block: on <<<<<<-----
> > > return-path: off
> > > pause-before-switchover: off
> > > x-multifd: off
> > >
> > > Fixes: 2833c59b947
> > > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > > ---
> > > migration/migration.c | 6 +++---
> > > 1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/migration/migration.c b/migration/migration.c
> > > index b913b98803..da0e4a1f56 100644
> > > --- a/migration/migration.c
> > > +++ b/migration/migration.c
> > > @@ -1391,11 +1391,12 @@ void qmp_migrate(const char *uri, bool has_blk,
> > > bool blk,
> > > return;
> > > }
> > > migrate_set_block_enabled(true, &local_err);
> > > + s->must_remove_block_options = true;
> > > if (local_err) {
> > > error_propagate(errp, local_err);
> > > + block_cleanup_parameters(s);
> > > return;
> > > }
> > > - s->must_remove_block_options = true;
> > > }
> > >
> > > if (has_inc && inc) {
> > > @@ -1417,11 +1418,10 @@ void qmp_migrate(const char *uri, bool has_blk,
> > > bool blk,
> > > } else if (strstart(uri, "fd:", &p)) {
> > > fd_start_outgoing_migration(s, p, &local_err);
> > > } else {
> > > - error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
> > > + error_setg(&local_err, QERR_INVALID_PARAMETER_VALUE, "uri",
> > > "a valid migration protocol");
> > > migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
> > > MIGRATION_STATUS_FAILED);
> > > - return;
> > > }
> > >
> > > if (local_err) {
> > > --
> > > 2.14.3
> > >
> >
> > Ouch...
> >
> > Instead it seems to be my fault in 4a84214ebe ("migration: provide
> > migrate_caps_check()", 2017-07-18). For now I cannot understand why I
> > did that before since it's obviously strange if without this
> > squashed...
> >
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 0aa596f867..88ed9375aa 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -747,13 +747,15 @@ void
> > qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
> > {
> > MigrationState *s = migrate_get_current();
> > MigrationCapabilityStatusList *cap;
> > + bool cap_list[MIGRATION_CAPABILITY__MAX];
> >
> > if (migration_is_setup_or_active(s->state)) {
> > error_setg(errp, QERR_MIGRATION_ACTIVE);
> > return;
> > }
> >
> > - if (!migrate_caps_check(s->enabled_capabilities, params, errp)) {
> > + memcpy(cap_list, s->enabled_capabilities, sizeof(cap_list));
> > + if (!migrate_caps_check(cap_list, params, errp)) {
> > return;
> > }
>
> >
> > Otherwise I'll get:
> >
> > (qemu) migrate_set_capability postcopy-ram on
> >
> > (qemu) migrate_set_capability compress on
> >
> > Postcopy is not currently compatible with compression
> >
> > (qemu) info migrate_capabilities
> > xbzrle: off
> > rdma-pin-all: off
> > auto-converge: off
> > zero-blocks: off
> > compress: on <------------------------- :(
> > events: off
> > postcopy-ram: on
> > x-colo: off
> > release-ram: off
> > block: off
> > return-path: off
> > pause-before-switchover: off
> > x-multifd: off
> >
> > And it looks very likely that this should solve the block bug too.
>
> Yes, it looks like it should - but it doesn't solve the 2nd of my cases;
> so we also need the 2nd half of my change.
>
> > (So I think either I got a brain fart last July, or now...)
>
> Of course it's the combination of two bugs :-)
Ah sure. :)
Please just let me know if you want me to post a patch, or I'll assume
you'll handle this together in the next post (and thanks anyways :)
--
Peter Xu