It is easier to track the current snapshot as part of the list of
snapshots. In particular, doing so lets us guarantee that the current
snapshot is cleared if that snapshot is removed from the list (rather
than depending on the caller to do so, and risking a use-after-free
problem, such as the one recently patched in 1db9d0efbf). This
requires the addition of several new accessor functions, as well as a
useful return type for virDomainSnapshotObjListRemove(). A few error
handling sites that were previously setting vm->current_snapshot =
NULL can now be dropped, because the previous function call has now
done it already. Also, qemuDomainRevertToSnapshot() was setting the
current vm twice, so keep only the one used on the success path.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The only use for the 'current' member of virDomainSnapshotDef was with
the PARSE/FORMAT_INTERNAL flag for controlling an internal-use
<active> element marking whether a particular snapshot definition was
current, and even then, only by the qemu driver on output, and by qemu
and test driver on input. But this duplicates vm->snapshot_current,
and gets in the way of potential simplifications to have qemu store a
single file for all snapshots rather than one file per snapshot. Get
rid of the member by adding a bool* parameter during parse (ignored if
the PARSE_INTERNAL flag is not set), and by adding a new flag during
format (if FORMAT_INTERNAL is set, the value printed in <active>
depends on the new FORMAT_CURRENT).
Then update the qemu driver accordingly, which involves hoisting
assignments to vm->current_snapshot to occur prior to any point where
a snapshot XML file is written (although qemu kept
vm->current_snapshot and snapshot->def_current in sync by the end of
the function, they were not always identical in the middle of
functions, so the shuffling gets a bit interesting). Later patches
will clean up some of that confusing churn to vm->current_snapshot.
Note: even if later patches refactor qemu to no longer use
FORMAT_INTERNAL for output (by storing bulk snapshot XML instead), we
will always need PARSE_INTERNAL for input (because on upgrade, a new
libvirt still has to parse XML left from a previous libvirt).
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
When a future patch converts virDomainSnapshotDef to be a virObject,
we need to be careful that converting VIR_FREE() to virObjectUnref()
does not result in double frees. Reorder the assignment of def into
the object to the point after object is in the hash table (as
otherwise the virHashAddEntry() error path would have a shot at
freeing def prematurely).
Suggested-by: John Ferlan <ferlan@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Change the return value of virDomainSnapshotObjListParse() to return
the number of snapshots imported, and allow a return of 0 (the
original proposal of adding a flag to virDomainSnapshotCreateXML
required returning an arbitrary non-NULL snapshot, but that idea was
abandoned; and by returning a count, we are no longer constrained to a
non-empty list).
Document which flags are supported (namely, just SECURE) in
virDomainSnapshotObjListFormat().
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
snapshot_conf.h was mixing three separate types: the snapshot
definition, the snapshot object, and the snapshot object list.
Separate out the snapshot object list code into its own file, and
update includes for affected clients.
This is just code motion, but done in preparation of sharing a lot of
the object list code with checkpoints.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
