Commit Graph

2953 Commits

Author SHA1 Message Date
Peter Krempa
693a044a21 qemu: driver: Don't pull in qemu_monitor_json.h directly
There's nothing that uses it directly now. Also not allowing direct use
will promote our layering.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-30 13:12:56 +02:00
Peter Krempa
b3d8c03c69 qemu: domain: Move checkpoint related code to qemu_checkpoint.c
Finish the refactor by moving and renaming functions from qemu_domain.c

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-30 13:12:56 +02:00
Peter Krempa
bc3088ca39 qemu: driver: Move checkpoint-related code to qemu_checkpoint.c
Move all extensive functions to a new file so that we don't just pile
everything in the common files. This obviously isn't possible with
straight code movement as we still need stubs in qemu_driver.c

Additionally some functions e.g. for looking up a checkpoint by name
were so short that moving the impl didn't make sense.

Note that in the move the new file also doesn't use
virQEMUMomentReparent but rather an stripped down copy. As I plan to
split out snapshot code into a separate file the unification doesn't
make sense any more.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-30 13:12:56 +02:00
Peter Krempa
c8ef580f7b qemu: checkpoint: Do ACL check prior to snapshot interlocking
The interlocking with snapshots is executed prior to the ACL check so if
a VM has snapshots invoking the checkpoint API may leak it's existance.

Introduced with the qemuDomainCheckpointCreateXML API implementation in
commit 5f4e079650.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2019-09-30 13:12:56 +02:00
Peter Krempa
7364f00eb3 qemu: driver: Remove misplaced qemuDomainObjEndJob in qemuDomainCheckpointGetXMLDesc
The code that gets the job to refresh disk sizes was not merged yet so
remove this artifact.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-27 15:23:42 +02:00
Peter Krempa
efeb6232c6 conf: Drop pointless 'domain' argument from virDomainSnapshotRedefinePrep
'vm' is passed in which contains the definition which contains the UUID
so we don't need another parameter for this.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-27 15:23:42 +02:00
Peter Krempa
4c94f8d8c1 conf: Drop pointless 'domain' argument from virDomainCheckpointRedefinePrep
'vm' is passed in which contains the definition which contains the UUID
so we don't need another parameter for this.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-27 15:23:42 +02:00
Peter Krempa
75f4a7b2c7 qemu: Move, rename and export qemuDomObjFromDomain
Move it to qemu_domain.c and rename it to qemuDomainObjFromDomain. This
will allow reusing it after splitting out checkpoint code from
qemu_driver.c.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-27 15:23:41 +02:00
Peter Krempa
742f599033 qemu: Simplify argument list of qemuDomainBlockPullCommon
Drop the 'driver' argument since it can be extracted from private data
to shorten the argument list.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-27 10:28:16 +02:00
Daniel Henrique Barboza
f372c27592 qemu_driver.c: use virConnectValidateURIPath()
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Suggested-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2019-09-26 17:25:20 -04:00
Laine Stump
7e490cdad6 conf: utility function to update entry in def->nets array
A virDomainNetDef object in a domain's nets array might contain a
virDomainHostdevDef, and when this is the case, the domain's hostdevs
array will also have a pointer to this embedded hostdev (this is done
so that internal functions that need to perform some operation on all
hostdevs won't leave out the type='hostdev' network interfaces).

When a network device was updated with virDomainUpdateDeviceFlags(),
we were replacing the entry in the nets array (and free'ing the
original) but forgetting about the pointer in the hostdevs array
(which would then point to the now-free'd hostdev contained in the old
net object.) This often resulted in a libvirtd crash.

The solution is to add a function, virDomainNetUpdate(), called by
qemuDomainUpdateDeviceConfig(), that updates the hostdevs array
appropriately along with the nets array.

Resolves: https://bugzilla.redhat.com/1558934

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-09-26 13:54:12 -04:00
Peter Krempa
3ebde403c7 qemu: driver: Remove unused cleanup labels in stats gathering functions
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
1bdf20c9df qemu: driver: Stop using QEMU_ADD_BLOCK_PARAM_ULL in qemuDomainGetStatsBlockExportFrontend
The macro now became unused so it was deleted.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
d4dcfdf7a3 qemu: driver: Stop using QEMU_ADD_BLOCK_PARAM_ULL in qemuDomainGetStatsBlockExportBackendStorage
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
585e260395 qemu: driver: Stop using QEMU_ADD_BLOCK_PARAM_ULL in qemuDomainGetStatsOneBlock
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
bb722855ca qemu: driver: Stop using QEMU_ADD_BLOCK_PARAM_ULL in qemuDomainGetStatsOneBlockFallback
The open-coded version does not take much more space and additionally we
get rid of the hidden goto.

This also requires us to remove the 'cleanup' section.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
2ccb5335dc qemu: Use virTypedParamList in the bulk stats gathering functions
The bulk stats functions are specific as they pass around the list into
many sub-functions and also a substantial amount of the entries uses
formatted names for indexing purposes. This makes them ideal to be
converted to the new virTypedParamList helpers.

Unfortunately given how the functions are used this requires a big-bang
rewrite of all of the calls to add entries to the parameter list.

Given that a substantial simplification is achieved as well as a pretty
significant change to the original code is required some macros which
were used only sporadically were replaced by inline calls rather than
tweaking the macros first and deleting them later.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
fc183b64d3 qemu: driver: Remove QEMU_ADD_BLOCK_PARAM_LL macro
Use QEMU_ADD_BLOCK_PARAM_ULL instead since all parameters are now
unsigned.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
e25dfbf58c qemu: driver: Don't return anything from qemuDomainBlockStatsGatherTotals
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
535b78ff03 qemu: driver: Remove pointless macro QEMU_BLOCK_STAT_TOTAL
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
f385dd3a47 qemu: monitor: Change fields in qemuBlockStats to 'unsigned'
None of the fields actually return negative values. The internal
implementation of BlockAcctStats struct in qemu uses uint64_t and the
last place using -1 in libvirt was in the HMP monitor code which was
deleted.

Change the internal type to unsigned long long and ensure that all
public conversions don't overflow.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
2717c3417a qemu: Remove stale comment for qemuDomainBlockStats
We no longer use HMP for this API.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-25 13:02:48 +02:00
Peter Krempa
fdff7294d1 qemu: checkpoint: Don't forbid checkpoint when VM is marked for autodestroy
The check was copied from the snapshot code and makes even less sense
here.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-25 08:38:52 +02:00
Peter Krempa
045a8e197c qemu: snapshot: Don't forbid snapshot if autodestroy is registered
Semantically VIR_DOMAIN_START_AUTODESTROY doesn't really clash with
snapshot operations as the VM stays on the same host and thus bound to
the same connection. Saving the state also doesn't differ from modifying
the state of the VM which is allowed.

Remove the check as it doesn't make much sense.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-25 08:38:51 +02:00
Peter Krempa
15340ff583 qemu: snapshot: Do ACL check prior to checkpoint interlocking
Commit 7efe930ec3 introduced interlock of snapshots and checkpoints,
but the check is executed prior to the snapshot API ACL check. This
means that an unauthorized user can see whether a VM exists if it has a
checkpoint.

Move the checks to proper places.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-09-23 16:42:54 +02:00
Xu Yandong
d72ed16ba7 qemuCheckDiskConfigAgainstDomain: Validate disk's SCSI address iff disk is SCSI
Check the disk SCSI address only when the disk actually is of
SCSI type.

Signed-off-by: Xu Yandong <xuyandong2@huawei.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-09-19 16:32:56 +02:00
Maxiwell S. Garcia
152c165d34 snapshot: Store both config and live XML in the snapshot domain
The snapshot-create operation of running guests saves the live
XML and uses it to replace the active and inactive domain in
case of revert. So, the config XML is ignored by the snapshot
process. This commit changes it and adds the config XML in the
snapshot XML as the <inactiveDomain> entry.

In case of offline guest, the behavior remains the same and the
config XML is saved in the snapshot XML as <domain> entry. The
behavior of older snapshots of running guests, that don't have
the new <inactiveDomain>, remains the same too. The revert, in
this case, overrides both active and inactive domain with the
<domain> entry. So, the <inactiveDomain> in the snapshot XML is
not required to snapshot work, but it's useful to preserve the
config XML of running guests.

Signed-off-by: Maxiwell S. Garcia <maxiwell@linux.ibm.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
2019-09-11 13:09:45 +02:00
Jiri Denemark
33c05f8b44 qemu: Don't leak domain def when RevertToSnapshot fails
Once we copy the domain definition from virDomainSnapshotDef, we either
need to assign it to the domain object or free it to avoid memory leaks.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2019-09-11 13:07:42 +02:00
Eric Blake
4933445a18 qemu: Fix regression in snapshot-revert
Commit f10562799 introduced a regression: if reverting to a snapshot
fails early (such as when we refuse to revert to an external
snapshot), we lose track of the domain's current snapshot.

Before that patch, we were tracking the notion of the domain's current
snapshot via two means: vm->current_snapshot (which was left untouched
on early exit) and snap->def->current (which only controls what gets
written to XML to remember snapshots across libvirtd restarts).  That
patch was fixing a real bug: if a revert operation failed early, later
questions from the same libvirtd did not see any change to the current
snapsthot, but restarting libvirtd would now claim there is no current
snapshot.  But it fixed it in the wrong direction, in that the current
snapshot was forgotten unconditionally, rather than only when the
snapshot to revert to has a chance of being useful.

It didn't help that the code after that patch had two separate spots
clearing the old notion of the current snapshot - one after
determining the snapshot to revert to was viable, the other
unconditionally on all failure exit paths.  At any rate, the fix is
simple: drop the unconditional cleanup on error paths, and rely only
on the normal cleanup after early checks.

Sadly, it is not possible to test this bug in the existing
tests/virsh-snapshot, as the test driver does not have the same
prohibition against reverting to an external snapshot as the qemu
driver.

See: https://bugzilla.redhat.com/1738747
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190909205242.15406-1-eblake@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2019-09-10 17:30:44 -05:00
Michal Privoznik
d301bc8d08 lib: Grab write lock when modifying list of domains
In some places where virDomainObjListForEach() is called the
passed callback calls virDomainObjListRemoveLocked(). Well, this
is unsafe, because the former only grabs a read lock but the
latter modifies the list.
I've identified the following unsafe calls:

- qemuProcessReconnectAll()
- libxlReconnectDomains()

The rest seem to be safe.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-07 08:22:30 +02:00
Marc-André Lureau
0755234389 qemu: add a flag to the cookie to prevent slirp-helper setup
For VM started and migrated/saved without slirp-helpers, let's prevent
the automatic setup (as it would fail to migrate otherwise).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-09-06 12:47:47 +02:00
Marc-André Lureau
5ac015efe1 qemu-conf: add slirp state dir
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-09-06 12:47:47 +02:00
Peter Krempa
a6aad9f29f qemu: Defer support checks for external active snapshots to blockdev code or qemu
Remove libvirt's support check for the target of an external snapshot to
the blockdev code or qemu. This will potentially require a more complex
cleanup but removes a level of hardcoded feature checks.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
a3f8abb003 qemu: Add -blockdev support for external snapshots
Use the code for creating or attaching new storage source in the
snapshot code and switch to 'blockdev-snapshot' for creating the
snapshot itself.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
b2904cb87b qemu: snapshot: Skip overlay file creation/interogation if unsupported
With blockdev we'll be able to support protocols which are not supported
by the storage backends in libvirt. This means that we have to be able
to skip the creation and relative storage path reading if it's not
supported. This will make it impossible to use relative backing for
network protocols but that would be almost insane anyways.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
e3189f7c0a qemu: Merge use of 'reuse' flag in qemuDomainSnapshotDiskPrepareOne
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
fd8e55ca93 qemu: Disband qemuDomainSnapshotCreateSingleDiskActive
After we always assume support for the 'transaction' command
(c358adc571) and follow-up cleanups
qemuDomainSnapshotCreateSingleDiskActive lost its value. Move the code
into appropriate helpers and remove the function.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
0d1622a1f4 qemu: snapshot: Rename external disk snapshot handling functions
Fix and unify the naming of external snapshot preparation functions.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
e1b61f2cd5 qemu: snapshot: Move error preservation to qemuDomainSnapshotDiskDataCleanup
Make qemuDomainSnapshotDiskDataCleanup cleanup section friendly by
moving the error preservation code inside it.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
93a0f72ef4 qemu: snapshot: Save status and config XMLs only on success
We changed to always saving the status and config XMLs to simplify
code. After a few more refactors it's now possible to move it to the
appropriate place and save the XMLs only on success again.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
e0720fda12 qemu: snapshot: Fix image lock handling when taking a snapshot
When we take a snapshot we must properly remove our locking
infrastructure locks. This was broken by commit 3817fa10c4 which
attempted to properly track the readonly state for the image as the
locking code was executed after this change. Since we forced the image
which was locked as read-write to read-only prior to unlocking it the
write lock was not dropped.

Fix it by moving the locking code prior to modifying the readonly flag.

https://bugzilla.redhat.com/show_bug.cgi?id=1745618

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
805b4aa2e9 qemu: driver: Fix shallow non-reuse block copy
The code preparing data for creating/attaching the target image of block
copy didn't use the correct reference to the existing backing chain in
case when the copy should inherit it. This meant that qemu actually
opened a second copy of the chain and operated on that.

This would de-sync qemu from libvirt's view of node names. Luckily this
is only hypothetical at this point since it happens only when -blockdev
is enabled.

Fix it by passing 'mirrorBacking' which has the proper data as the
backing store when calling
qemuBuildStorageSourceChainAttachPrepareBlockdevTop.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
b5e7460b23 qemu: Explicitly pass backing store to qemuBuildStorageSourceChainAttachPrepareBlockdevTop
In some cases we'll need to pass in a backing store which is not
recorded as the backing store of @src. Export backingStore as variable
and fix all callers to pass in the backing store. No semantic changes
for now.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Peter Krempa
510d154a0b qemu: Prevent storage causing too much nested XML
Since libvirt stores the backing chain into the XML in a nested way it
is the prime possibility to hit libxml2's parsing limit of 256 layers.

Introduce code which will crawl the backing chain and verify that it's
not too deep. The maximum nesting is set to 200 layers so that there's
still some space left for additional properties or nesting into snapshot
XMLs.

The check is applied to all disk use cases (starting, hotplug, media
change) as well as block copy which changes image and snapshots.

We simply report an error and refuse the operation.

Without this check a restart of libvirtd would result in the status XML
failing to be parsed and thus losing the VM.

https://bugzilla.redhat.com/show_bug.cgi?id=1524278

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-09-06 08:12:21 +02:00
Jonathon Jongsma
a931486a97 qemu: guestinfo: handle unsupported agent commands
When we're collecting guest information, older agents may not support
all agent commands. In the case where the user requested all info
types (i.e. types == 0), ignore unsupported command errors and gather as
much information as possible. If the agent command failed for some other
reason, or if the user explciitly requested a specific info type (i.e.
types != 0), abort on the first error.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2019-08-29 12:03:23 +02:00
Michal Privoznik
3853372659 qemu: Don't duplicate domain def in qemuDomainGetFSInfo
Introduced in v3.0.0-rc1~336, the commit message doesn't really
justifies the expensive domain def copy creation. Now, that
vm->def is guarded in this function by job acquirement we can use
vm->def directly.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-27 14:23:29 +02:00
Michal Privoznik
93841cb030 qemu: Acquire domain job in qemuDomainGetFSInfo and qemuDomainGetGuestInfo
These two functions work with vm->def in their critical sections
(i.e. after the job was acquired and before it is released). But
that means, they need QUERY domain job too to prevent vm->def
change.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-27 14:14:34 +02:00
Jonathon Jongsma
02697fdbd1 qemu: Implement virDomainGetGuestInfo()
Iimplements the new guest information API by querying requested
information via the guest agent.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Tested-by: Daniel Henrique Barboza <danielhb413@gmail.com>
2019-08-26 17:27:40 +02:00
Peter Krempa
9d6737764f qemu: Split out preparing of single snapshot from qemuDomainSnapshotDiskDataCollect
Move the internals into qemuDomainSnapshotDiskDataCollectOne to make it
obvious what's happening after moving more code here.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-26 13:49:18 +02:00
Peter Krempa
9d80fdcd63 qemu: snapshot: Restrict file existence check only for local storage
Soon we'll allow more protocols and storage types with snapshots where
we in some cases can't check whether the storage already exists.
Restrict the sanity checks whether the destination images exist or not
for local storage where it's easy. For any other case we will fail
later.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-08-26 13:49:17 +02:00