Currently, qemu driver uses qemuTranslateDiskSourcePool()
to translate disk volume information. This function is
general enough and could be used for other drivers as well,
so move it to conf/domain_conf.c along with its helpers.

 - qemuTranslateDiskSourcePool: move to storage/storage_driver.c
   and rename to virStorageTranslateDiskSourcePool,
 - qemuAddISCSIPoolSourceHost: move to storage/storage_driver.c
   and rename to virStorageAddISCSIPoolSourceHost,
 - qemuTranslateDiskSourcePoolAuth: move to storage/storage_driver.c
   and rename to virStorageTranslateDiskSourcePoolAuth,
 - Update users of qemuTranslateDiskSourcePool to use a
   new name.

Implement ZFS storage backend driver. Currently supported
only on FreeBSD because of ZFS limitations on Linux.

Features supported:

 - pool-start, pool-stop
 - pool-info
 - vol-list
 - vol-create / vol-delete

Pool definition looks like that:

 <pool type='zfs'>
  <name>myzfspool</name>
  <source>
    <name>actualpoolname</name>
  </source>
 </pool>

The 'actualpoolname' value is a name of the pool on the system,
such as shown by 'zpool list' command. Target makes no sense
here because volumes path is always /dev/zvol/$poolname/$volname.

User has to create a pool on his own, this driver doesn't
support pool creation currently.

A volume could be used with Qemu by adding an entry like this:

    <disk type='volume' device='disk'>
      <driver name='qemu' type='raw'/>
      <source pool='myzfspool' volume='vol5'/>
      <target dev='hdc' bus='ide'/>
    </disk>

https://bugzilla.redhat.com/show_bug.cgi?id=1072653

Upon successful upload of a volume, the target volume and storage pool
were not updated to reflect any changes as a result of the upload. Make
use of the existing stream close callback mechanism to force a backend
pool refresh to occur in a separate thread once the stream closes. The
separate thread should avoid potential deadlocks if the refresh needed
to wait on some event from the event loop which is used to perform
the stream callback.

With my intended use of storage driver assist to chown files on remote
storage we will need a witness that will tell us whether the given
storage volume supports operations needed by the storage driver.

Gluster storage works on a similar principle to NFS where it takes the
uid and gid of the actual process and uses it to access the storage
volume on the remote server. This introduces a need to chown storage
files on gluster via native API.

Rather than a unsigned int, use a 'bool' since that's how it was used.

For non-local storage drivers we can't expect to use the "scrub" tool to
wipe the volume. Split the code into a separate backend function so that
we can add protocol specific code later.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1118710

The next patch will move the storage volume wiping code into the
individual backends. This patch splits out the common code to wipe a
local volume into a separate backend helper so that the next patch is
simpler.

For non-local storage drivers we can't expect to use the FDStream
backend for up/downloading volumes. Split the code into a separate
backend function so that we can add protocol specific code later.

Allow de-init of null storage sources.

The parent directory doesn't necessarily need to be stored after we
don't mangle the path stored in the image. Remove it and tweak the code
to avoid using it.

Due to various refactors and compatibility with the virstoragetest the
relPath field of the virStorageSource structure was always filled either
with the relative name or the full path in case of absolutely backed
storage. Return its original purpose to store only the relative name of
the disk if it is backed relatively and tweak the tests.

Introduced by commit 2bdb8b96

Add a helper to do all the lookup steps and remove a ton of duplicated
code.

Most of the APIs now don't reach the cleanup section when the pool
object wasn't found and thus don't need to check before unlocking it.

Rework internal pool lookup code to avoid printing the raw UUID buffer
in the case a storage pool can't be found:

 $ virsh pool-name e012ace0-0460-5810-39ef-1bce5fa5a4dd
 error: failed to get pool 'e012ace0-0460-5810-39ef-1bce5fa5a4dd'
 error: Storage pool not found: no storage pool with matching uuid à¬à`X9ï_¥¤Ý

The rework is mostly done by switching the lookup code to the newly
introduced helper virStoragePoolObjFromStoragePool

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1104993

Now we don't need to skip backing chain detection for remote disks.

Use the new backing store parser in the backing chain crawler. This
change needs one test change where information about the NBD image are
now parsed differently.

Use virStorageFileAccess() to to check whether the file is accessible in
the main part of the metadata crawler.

Use virStorageFileReadHeader() to read headers of storage files possibly
on remote storage to retrieve the image metadata.

The backend information is now parsed by
virStorageFileGetMetadataInternal which is now exported from the util
source and virStorageFileGetMetadataFromFDInternal now doesn't need to
be exported.

Use the virStorageFileGetUniqueIdentifier() function to get a unique
identifier regardless of the target storage type instead of relying on
canonicalize_path().

A new function that checks whether we support a given image is
introduced to avoid errors for unimplemented backends.

When walking the backing chain we previously set the storage type to
_FILE and let the virStorageFileGetMetadataFromFDInternal update it to
the correct type later on.

This patch moves the actual storage type determination to the place
where we parse the backing store name so that the code can later be
switched to use virStorageFileReadHeader() directly.

My future work will modify the metadata crawler function to use the
storage driver file APIs to access the files instead of accessing them
directly so that we will be able to request the metadata for remote
files too. To avoid linking the storage driver to every helper file
using the utils code, the backing chain traversal function needs to be
moved to the storage driver source.

Additionally the virt-aa-helper and virstoragetest programs need to be
linked with the storage driver as a result of this change.

Add a storage driver API equivalent of the access() function.
Implementations for the filesystem and gluster backends are provided.

Different protocols have different means to uniquely identify a storage
file. This patch implements a storage driver API to retrieve a unique
string describing a volume. The current implementation works for local
storage only and returns the canonical path of the volume.

To add caching support the local filesystem driver now has a private
structure holding the cached string, which is created only when it's
initially accessed.

This patch provides the implementation for local files only for start.

Raised by ukrainian translator Yuri Chornoivan
https://fedora.transifex.com/projects/p/libvirt/translate/#uk/strings/25483059

Add storage driver based functions to access headers of storage files
for metadata extraction. Along with this patch a local filesystem and
gluster via libgfapi implementation is provided. The gluster
implementation is based on code of the saferead_lim function.

To allow using the storage driver APIs to access files on various
storage sources in a universal fashion possibly on storage such as nfs
with root squash we'll need to store the desired uid/gid in the
metadata.

Add new initialisation API that will store the desired uid/gid and a
wrapper for the current use. Additionally add docs for the two APIs.

Print the debug statements of individual file access functions from the
main API functions instead of the individual backend functions.

Also enhance initialization debug messages on a per-backend basis.

In "src/conf/" there are many enumeration (enum) declarations.
Similar to the recent cleanup to "src/util" directory, it's
better to use a typedef for variable types, function types and
other usages. Other enumeration and folders will be changed to
typedef's in the future. Most of the files changed in this
commit are related to storage (storage_conf) enums.
Signed-off-by: NJulio Faracco <jcfaracco@gmail.com>
Signed-off-by: NEric Blake <eblake@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1092882

Refactoring in commit id '0c2305b3' resulted in the wrong storage
volume object being passed to the new storageVolDeleteInternal().
It should have passed 'voldef' which is the address found in the
pool->volumes.objs[i] array.  By passing 'voldef', the DeleteInternal
code will find and remove the voldef from the volumes.objs[] list.

When creating a new volume, it is possible to copy data into it from
another already existing volume (referred to as @origvol). Obviously,
the read-only access to @origvol is required, which is thread safe
(probably not performance-wise though). However, with current code
both @newvol and @origvol are marked as building for the time of
copying data from the @origvol to @newvol. The rationale behind
is to disallow some operations on both @origvol and @newvol, e.g.
vol-wipe, vol-delete, vol-download. While it makes sense to not allow
such operations on partly copied mirror, but it doesn't make sense to
disallow vol-create or vol-download on the source (@origvol).
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Now that we store all metadata about a storage image in a
virStorageSource struct let's use it also to store information needed by
the storage driver to access and do operations on the files.

Now that storage source metadata is stored in a single struct we don't
need two initialization functions for different structs.

Now that the storage source definition is uniform convert the helpers to
retrieve the actual storage type to a single one.

https://bugzilla.redhat.com/show_bug.cgi?id=1024159

If adding a volume to a storage pool fails during the CreateXML or
CreateXMLFrom API's, we don't want to adjust the available and
allocation values for the storage pool during storageVolDelete
since we haven't adjusted the values for the create.

Refactor storageVolDelete() a bit to create a storageVolDeleteInternal()
which will handle the primary deletion activities.  Add a parameter
updateMeta which will signify whether to update the values or not.

Adjust the calls from CreateXML and CreateXMLFrom to directly call the
DeleteInternal with the pool lock held.  This does bypass the call
to virStorageVolDeleteEnsureACL().

One of the features of qcow2 is that a wrapper file can have
more capacity than its backing file from the guest's perspective;
what's more, sparse files make tracking allocation of both
the active and backing file worthwhile.  As such, it makes
more sense to show allocation numbers for each file in a chain,
and not just the top-level file.  This sets up the fields for
the tracking, although it does not modify XML to display any
new information.

* src/util/virstoragefile.h (_virStorageSource): Add fields.
* src/conf/storage_conf.h (_virStorageVolDef): Drop redundant
fields.
* src/storage/storage_backend.c (virStorageBackendCreateBlockFrom)
(createRawFile, virStorageBackendCreateQemuImgCmd)
(virStorageBackendCreateQcowCreate): Update clients.
* src/storage/storage_driver.c (storageVolDelete)
(storageVolCreateXML, storageVolCreateXMLFrom, storageVolResize)
(storageVolWipeInternal, storageVolGetInfo): Likewise.
* src/storage/storage_backend_fs.c (virStorageBackendProbeTarget)
(virStorageBackendFileSystemRefresh)
(virStorageBackendFileSystemVolResize)
(virStorageBackendFileSystemVolRefresh): Likewise.
* src/storage/storage_backend_logical.c
(virStorageBackendLogicalMakeVol)
(virStorageBackendLogicalCreateVol): Likewise.
* src/storage/storage_backend_scsi.c
(virStorageBackendSCSINewLun): Likewise.
* src/storage/storage_backend_mpath.c
(virStorageBackendMpathNewVol): Likewise.
* src/storage/storage_backend_rbd.c
(volStorageBackendRBDRefreshVolInfo)
(virStorageBackendRBDCreateImage): Likewise.
* src/storage/storage_backend_disk.c
(virStorageBackendDiskMakeDataVol)
(virStorageBackendDiskCreateVol): Likewise.
* src/storage/storage_backend_sheepdog.c
(virStorageBackendSheepdogBuildVol)
(virStorageBackendSheepdogParseVdiList): Likewise.
* src/storage/storage_backend_gluster.c
(virStorageBackendGlusterRefreshVol): Likewise.
* src/conf/storage_conf.c (virStorageVolDefFormat)
(virStorageVolDefParseXML): Likewise.
* src/test/test_driver.c (testOpenVolumesForPool)
(testStorageVolCreateXML, testStorageVolCreateXMLFrom)
(testStorageVolDelete, testStorageVolGetInfo): Likewise.
* src/esx/esx_storage_backend_iscsi.c (esxStorageVolGetXMLDesc):
Likewise.
* src/esx/esx_storage_backend_vmfs.c (esxStorageVolGetXMLDesc)
(esxStorageVolCreateXML): Likewise.
* src/parallels/parallels_driver.c (parallelsAddHddByVolume):
Likewise.
* src/parallels/parallels_storage.c (parallelsDiskDescParseNode)
(parallelsStorageVolDefineXML, parallelsStorageVolCreateXMLFrom)
(parallelsStorageVolDefRemove, parallelsStorageVolGetInfo):
Likewise.
* src/vbox/vbox_tmpl.c (vboxStorageVolCreateXML)
(vboxStorageVolGetXMLDesc): Likewise.
* tests/storagebackendsheepdogtest.c (test_vdi_list_parser):
Likewise.
* src/phyp/phyp_driver.c (phypStorageVolCreateXML): Likewise.

Now that we have a common struct, it's time to start using it!
Since external snapshots make a longer backing chain, it is
only natural to use the same struct for the file created by
the snapshot as what we use for <domain> disks.

* src/conf/snapshot_conf.h (_virDomainSnapshotDiskDef): Use common
struct instead of open-coded duplicate fields.
* src/conf/snapshot_conf.c (virDomainSnapshotDiskDefClear)
(virDomainSnapshotDiskDefParseXML, virDomainSnapshotAlignDisks)
(virDomainSnapshotDiskDefFormat)
(virDomainSnapshotDiskGetActualType): Adjust clients.
* src/qemu/qemu_conf.c (qemuTranslateSnapshotDiskSourcePool):
Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiskGetSourceString)
(qemuDomainSnapshotCreateInactiveExternal)
(qemuDomainSnapshotPrepareDiskExternalOverlayActive)
(qemuDomainSnapshotPrepareDiskExternal)
(qemuDomainSnapshotPrepare)
(qemuDomainSnapshotCreateSingleDiskActive): Likewise.
* src/storage/storage_driver.c
(virStorageFileInitFromSnapshotDef): Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

Continuing the refactoring of host-side storage descriptions out
of conf/domain_conf and into util/virstoragefile, this patch
focuses on details about a host name/port/transport as used by
a network storage volume.

* src/conf/domain_conf.h (virDomainDiskProtocolTransport)
(virDomainDiskHostDef, virDomainDiskHostDefClear)
(virDomainDiskHostDefFree, virDomainDiskHostDefCopy): Move...
* src/util/virstoragefile.h (virStorageNetHostTransport)
(virStorageNetHostDef, virStorageNetHostDefClear)
(virStorageNetHostDefFree, virStorageNetHostDefCopy): ...here,
with better names.
* src/util/virstoragefile.c (virStorageNetHostDefClear)
(virStorageNetHostDefFree, virStorageNetHostDefCopy): Moved from...
* src/conf/domain_conf.c (virDomainDiskHostDefClear)
(virDomainDiskHostDefFree, virDomainDiskHostDefCopy): ...here.
(virDomainDiskSourceDefClear, virDomainDiskSourceDefParse)
(virDomainDiskSourceDefFormatInternal): Adjust callers.
* src/conf/snapshot_conf.h (_virDomainSnapshotDiskDef): Likewise.
* src/conf/snapshot_conf.c (virDomainSnapshotDiskDefClear):
Likewise.
* src/qemu/qemu_command.c (qemuAddRBDHost)
(qemuParseDriveURIString, qemuParseNBDString)
(qemuBuildNetworkDriveURI, qemuParseCommandLineDisk)
(qemuParseCommandLine, qemuGetDriveSourceString): Likewise.
* src/qemu/qemu_command.h: Likewise.
* src/qemu/qemu_conf.c (qemuAddISCSIPoolSourceHost)
(qemuTranslateDiskSourcePool): Likewise.
* src/qemu/qemu_driver.c
(qemuDomainSnapshotCreateSingleDiskActive)
(qemuDomainSnapshotUndoSingleDiskActive): Likewise.
* src/storage/storage_backend_gluster.c
(virStorageFileBackendGlusterInit): Likewise.
* src/storage/storage_driver.c (virStorageFileFree)
(virStorageFileInitInternal): Likewise.
* src/storage/storage_driver.h (_virStorageFile): Likewise.
* src/libvirt_private.syms (domain_conf.h): Move symbols...
(virstoragefile.h): ...as appropriate.
Signed-off-by: NEric Blake <eblake@redhat.com>