The incoming migration is processed in a coroutine and uses an fd read
handler to enter the yielded coroutine when data becomes available.
The read handler was set too broadly, so that spurious coroutine entries
were be triggered if other coroutine users yielded (like the block
layer's bdrv_write() function).
Install the fd read only only when yielding for more data to become
available. This prevents spurious coroutine entries which break code
that assumes only a specific set of places can re-enter the coroutine.
This patch fixes crashes in block/raw-posix.c that are triggered with
"migrate -b" when qiov becomes a dangling pointer due to a spurious
coroutine entry that frees qiov early.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1360598505-5512-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
This will allow us finer control in next patches.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we have error handling we can do proper handling of
buffered_flush().
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
The call in buffered_close is enough, because buffered_close is called
already by migrate_fd_cleanup.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
commit 5b4e1eb769
missed this use.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Reviewed-by: Eric Blake <eblake@redhat.com>
Avoid splitting the state of outgoing migration, more or less arbitrarily,
between two data structures. QEMUFileBuffered anyway is used only during
migration.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The "magic" divisions by 10 are there because of the value of BUFFER_DELAY.
Introduce a constant to explain them better.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This only moves the code (also from buffered_file.h to migration.h).
Fix whitespace until checkpatch is happy.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Code just now does (simplified for clarity)
if (qemu_savevm_state_iterate(s->file) == 1) {
vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
qemu_savevm_state_complete(s->file);
}
Problem here is that qemu_savevm_state_iterate() returns 1 when it
knows that remaining memory to sent takes less than max downtime.
But this means that we could end spending 2x max_downtime, one
downtime in qemu_savevm_iterate, and the other in
qemu_savevm_state_complete.
Changed code to:
pending_size = qemu_savevm_state_pending(s->file, max_size);
DPRINTF("pending size %lu max %lu\n", pending_size, max_size);
if (pending_size >= max_size) {
ret = qemu_savevm_state_iterate(s->file);
} else {
vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
qemu_savevm_state_complete(s->file);
}
So what we do is: at current network speed, we calculate the maximum
number of bytes we can sent: max_size.
Then we ask every save_live section how much they have pending. If
they are less than max_size, we move to complete phase, otherwise we
do an iterate one.
This makes things much simpler, because now individual sections don't
have to caluclate the bandwidth (it was implossible to do right from
there).
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we have a thread, and blocking writes, we don't need it.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Move all the writes to the migration_thread, and make writings
blocking. Notice that are still using the iothread for everything
that we do.
Signed-off-by: Juan Quintela <quintela@redhat.com>
We want the file assignment to happen before the thread is created to
avoid locking, so we just do it before creating the thread.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
The call in buffered_close is enough, because buffered_close is called
already by migrate_fd_cleanup.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
The final part of incoming migration, which now consists of
process_incoming_migration for all protocols, is thus made non-blocking.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The common suffix is now just process_incoming_migration.
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
migrate_fd_cleanup will usually close the file descriptor via
buffered_file_close's call to migrate_fd_close. However, in the case
of s->file == NULL it is "inlining" migrate_fd_close (almost: there is a
direct close() instead of using s->close(s)). To fix the inconsistency
and clean up the code, allow multiple calls to migrate_fd_close and use
the function in migrate_fd_cleanup.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* 'queue/qmp' of git://repo.or.cz/qemu/qmp-unstable:
migration: go to paused state after finishing incoming migration with -S
qmp: handle stop/cont in INMIGRATE state
hmp: fix info cpus for sparc targets
At the end of migration the machine has started already, and cannot be
destroyed without losing the guest's data. Hence, prelaunch is the
wrong state. Go to the paused state instead. QEMU would reach that
state anyway (after running the guest for the blink of an eye) if the
"stop" command had been received after the start of migration.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
And remove the superfluous integer return value.
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Error propagation is already there for socket backends. Add it to other
protocols, simplifying code that tests for errors that will never happen.
With all protocols understanding Error, the code can be simplified
further by removing the return value.
Unfortunately, the quality of error messages varies depending
on where the error is detected, because no Error is passed to the
NonBlockingConnectHandler. Thus, the exact error message still cannot
be sent to the user if the OS reports it asynchronously via SO_ERROR.
If NonBlockingConnectHandler received an Error**, we could for
example report the error class and/or message via a new field of the
query-migration command even if it is reported asynchronously.
Before:
(qemu) migrate fd:ffff
migrate: An undefined error has occurred
(qemu) info migrate
(qemu)
After:
(qemu) migrate fd:ffff
migrate: File descriptor named 'ffff' has not been found
(qemu) info migrate
capabilities: xbzrle: off
Migration status: failed
total time: 0 milliseconds
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This makes migration-unix.c again a cut-and-paste job from migration-tcp.c,
exactly as it was in the beginning. :)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The call to migrate_fd_error() was missing for non-socket backends, so
centralize it in qmp_migrate().
Before:
(qemu) migrate fd:ffff
migrate: An undefined error has occurred
(qemu) info migrate
(qemu)
After:
(qemu) migrate fd:ffff
migrate: An undefined error has occurred
(qemu) info migrate
capabilities: xbzrle: off
Migration status: failed
total time: 0 milliseconds
(The awful error message will be fixed later in the series).
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The migration code is using errp to detect "internal" errors, this means
that it relies on errp being non-NULL.
No impact so far because our only QMP clients (the QMP marshaller and HMP)
never pass a NULL Error **. But if we had others, this patch would make
sure that migration can work with a NULL Error **.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We only use it once, just remove the callback indirection.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
We only used it once, just remove the callback indirection
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Stefan Hajnoczi