QEMU uses curl for accessing files using http(s) and ftp(s). They share
common options so let's generate them in one helper.

Libvirt historically stores storage source path including the volume as
one string in the XML, but that is not really flexible enough when
dealing with the fields in the code. Previously we'd store the slash
separating the two as part of the image name. This was fine for gluster
but it's not necessary and does not scale well when converting other
protocols.

Don't store the slash as part of the path. The resulting change from
absolute to relative path within the gluster driver should be okay,
as the root directory is the default when accessing gluster.

Extract the part formatting the basic URI part so that it can be reused
to format JSON backing definitions. Parts specific to the command line
format will remain in qemuBuildNetworkDriveURI. The new function is
called qemuBlockStorageSourceGetURI.

Original implementation used 'SocketAddress' equivalent from qemu for
the disk server field, while qemu documentation specifies
'InetSocketAddress'. The backing store parser uses the correct parsing
function but the formatter used the incorrect one (and also with the
legacy mode enabled which was wrong).

qemuBlockStorageSourceGetBackendProps now is able to format the JSON
definition for regular storage too.

The file object is needed when formatting the command line, but it makes
nesting of the objects less easy for use with blockdev. Separate the
wrapping into the 'file' object into a helper used specifically for disk
sources in the old code path.

Add helpers that will simplify checking if a backing file is valid or
whether it has backing store. The helper virStorageSourceIsBacking
returns true if the given virStorageSource is a valid backing store
member. virStorageSourceHasBacking returns true if the virStorageSource
has a backing store child.

Adding these functions creates a central points for further refactors.

Alter qemu command line generation in order to possibly add TLS for
a suitably configured domain.

Sample TLS args generated by libvirt -

    -object tls-creds-x509,id=objvirtio-disk0_tls0,dir=/etc/pki/qemu,\
    endpoint=client,verify-peer=yes \
    -drive file.driver=vxhs,file.tls-creds=objvirtio-disk0_tls0,\
    file.vdisk-id=eb90327c-8302-4725-9e1b-4e85ed4dc251,\
    file.server.type=tcp,file.server.host=192.168.0.1,\
    file.server.port=9999,format=raw,if=none,\
    id=drive-virtio-disk0,cache=none \
    -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,\
    id=virtio-disk0

Update the qemuxml2argvtest with a couple of examples. One for a
simple case and the other a bit more complex where multiple VxHS disks
are added where at least one uses a VxHS that doesn't require TLS
credentials and thus sets the domain disk source attribute "tls = 'no'".

Update the hotplug to be able to handle processing the tlsAlias whether
it's to add the TLS object when hotplugging a disk or to remove the TLS
object when hot unplugging a disk.  The hot plug/unplug code is largely
generic, but the addition code does make the VXHS specific checks only
because it needs to grab the correct config directory and generate the
object as the command line would do.
Signed-off-by: NAshish Mittal <Ashish.Mittal@veritas.com>
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

The alias recorded in disk->info.alias is the alias for the frontend
device but we are interested in the backend drive. This messed up the
disk node name extraction code as qemu reports the drive alias in the
block query commands. This was broken in the node name detector
refactoring done in commit 0175dc6e

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1494327

Move the check that skips node name detection if they are already
present earlier so that the hash table lookup is skipped.

The VxHS block device will only use the newer formatting options and
avoid the legacy URI syntax.

An excerpt for a sample QEMU command line is:

  -drive file.driver=vxhs,file.vdisk-id=eb90327c-8302-4725-9e1b-4e85ed4dc251,\
   file.server.type=tcp,file.server.host=192.168.0.1,\
   file.server.port=9999,format=raw,if=none,id=drive-virtio-disk0,cache=none \
  -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,\
   id=virtio-disk0

Update qemuxml2argvtest with a simple test.
Signed-off-by: NAshish Mittal <Ashish.Mittal@veritas.com>
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Extract out the "guts" of building a server entry into it's own
separately callable/usable function in order to allow building
a server entry for a consumer with src->nhosts == 1.

Add a new virStorageNetProtocol for Veritas HyperScale (VxHS) disks
Signed-off-by: NAshish Mittal <Ashish.Mittal@veritas.com>
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Store the 'drv' field both for the storage node and for the format node
and format them in the test case.
Reviewed-by: NEric Blake <eblake@redhat.com>

Remove the complex and unreliable code which inferred the node name
hierarchy only from data returned by 'query-named-block-nodes'. It turns
out that query-blockstats contain the full hierarchy of nodes as
perceived by qemu so the inference code is not necessary.

In query blockstats, the 'parent' object corresponds to the storage
behind a storage volume and 'backing' corresponds to the lower level of
backing chain. Since all have node names this data can be really easily
used to detect node names.

In addition to the code refactoring the one remaining test case needed
to be fixed along.
Reviewed-by: NEric Blake <eblake@redhat.com>

Make it less confusing by naming the field which refers to the storage
object as 'nodestorage'.
Reviewed-by: NEric Blake <eblake@redhat.com>

The same operation will become useful in other places so rename the
function to be more generic and move it to the top so that it can be
reused earlier in the file.
Reviewed-by: NEric Blake <eblake@redhat.com>

Currently, @port is type of string. Well, that's overkill and
waste of memory. Port is always an integer. Use it as such.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Recent refactors made it so that the function may use uninitialized
pointer, but it actually wanted to use a different variable and value
at all.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

New name is qemuBlockStorageSourceGetGlusterProps and also hardcode the
protocol name rather than calling the ToString function, since this
function can't be made universal.

New name is qemuBlockStorageSourceBuildHostsJSONSocketAddress since it
formats the JSON object in accordance with qemu's SocketAddress type.

Since the new naming in qemu uses 'inet' instead of 'tcp' add a
compatibility layer for gluster which uses the old name.

Rename it to qemuBlockStorageSourceGetBackendProps and refactor it to
return the JSON object instead of filling a pointer since now it's
always expected to return data.

Pure code movement except for the tweaks necessary for cross-usage.

Becase it can be called during migration out (namely on cancelling
blockjobs).
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

To allow updating stats based on the node name, add a helper function
that will fetch the required data from 'query-named-block-nodes' and
return it in hash table for easy lookup.

Detect the node names when setting block threshold and when reconnecting
or when they are cleared when a block job finishes. This operation will
become a no-op once we fully support node names.

qemu for some time already sets node names automatically for the block
nodes. This patch adds code that attempts a best-effort detection of the
node names for the backing chain from the output of
'query-named-block-nodes'. The only drawback is that the data provided
by qemu needs to be matched by the filename as seen by qemu and thus
if two disks share a single backing store file the detection won't work.

This will allow us to use qemu commands such as
'block-set-write-threshold' which only accepts node names.

In this patch only the detection code is added, it will be used later.