[libvirt] [PATCH RFC] storage: ZFS support
Ján Tomko
jtomko at redhat.com
Thu Jul 24 08:37:41 UTC 2014
On 07/22/2014 07:08 PM, Roman Bogorodskiy wrote:
> 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.
>
> Users 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>
> ---
Looks good to me, just a few nits below:
> configure.ac | 43 +++++
> include/libvirt/libvirt.h.in | 1 +
> po/POTFILES.in | 1 +
> src/Makefile.am | 8 +
> src/conf/storage_conf.c | 11 +-
> src/conf/storage_conf.h | 4 +-
> src/qemu/qemu_conf.c | 1 +
> src/storage/storage_backend.c | 6 +
> src/storage/storage_backend_zfs.c | 344 ++++++++++++++++++++++++++++++++++++++
> src/storage/storage_backend_zfs.h | 29 ++++
> src/storage/storage_driver.c | 1 +
> tools/virsh-pool.c | 3 +
> 12 files changed, 449 insertions(+), 3 deletions(-)
> create mode 100644 src/storage/storage_backend_zfs.c
> create mode 100644 src/storage/storage_backend_zfs.h
>
Missing additions to docs/schemas and docs/storage.html.in
> diff --git a/src/storage/storage_backend_zfs.c b/src/storage/storage_backend_zfs.c
> new file mode 100644
> index 0000000..1079bc7
> --- /dev/null
> +++ b/src/storage/storage_backend_zfs.c
> @@ -0,0 +1,344 @@
> +/*
> + * storage_backend_zfs.c: storage backend for ZFS handling
> + *
> + * Copyright (C) 2014 Roman Bogorodskiy
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library. If not, see
> + * <http://www.gnu.org/licenses/>.
> + *
> + */
> +
> +#include <config.h>
> +
> +#include "viralloc.h"
> +#include "virerror.h"
> +#include "virfile.h"
> +#include "storage_backend_zfs.h"
> +#include "virlog.h"
> +#include "virstring.h"
> +
> +#define VIR_FROM_THIS VIR_FROM_STORAGE
> +
> +VIR_LOG_INIT("storage.storage_backend_zfs");
> +
> +/*
> + * Some common flags of zfs and zpool commands we use:
> + * -H -- don't print headers and separate fields by tab
> + * -p -- show exact numbers instead of human-readable, i.e.
> + * for size, show just a number instead of 2G etc
> + */
> +
> +
> +static int
> +virStorageBackendZFSCheckPool(virConnectPtr conn ATTRIBUTE_UNUSED,
> + virStoragePoolObjPtr pool ATTRIBUTE_UNUSED,
> + bool *isActive)
> +{
> + char *devpath;
> +
> + if (virAsprintf(&devpath, "/dev/zvol/%s",
> + pool->def->source.name) == -1)
> + return -1;
> + *isActive = virFileIsDir(devpath);
> + VIR_FREE(devpath);
> +
> + return 0;
> +}
> +
> +static int
> +virStorageBackendZFSStartPool(virConnectPtr conn ATTRIBUTE_UNUSED,
> + virStoragePoolObjPtr pool ATTRIBUTE_UNUSED)
> +{
> + return 0;
> +}
This doesn't need to be implemented if it doesn't do anything (same for StopPool)
> +static int
> +virStorageBackendZFSRefreshPool(virConnectPtr conn ATTRIBUTE_UNUSED,
> + virStoragePoolObjPtr pool ATTRIBUTE_UNUSED)
> +{
> + virCommandPtr cmd = NULL;
> + char *zpool_props = NULL;
> + char **lines = NULL;
> + size_t i;
> +
> + /**
> + * $ zpool get -Hp health,size,free,allocated test
> + * test health ONLINE -
> + * test size 199715979264 -
> + * test free 198899976704 -
> + * test allocated 816002560 -
> + * $
> + *
> + * Here we just provide a list of properties we want to see
> + */
> + cmd = virCommandNewArgList(ZPOOL,
> + "get", "-Hp",
> + "health,size,free,allocated",
> + pool->def->source.name,
> + NULL);
> + virCommandSetOutputBuffer(cmd, &zpool_props);
> + if (virCommandRun(cmd, NULL) < 0)
> + goto cleanup;
> +
> + if (!(lines = virStringSplit(zpool_props, "\n", 0)))
> + goto cleanup;
> +
> + for (i = 0; lines[i]; i++) {
> + char **tokens;
> + size_t count;
> + char *prop_name;
> +
> + if (STREQ(lines[i], ""))
> + continue;
> +
> + if (!(tokens = virStringSplitCount(lines[i], "\t", 0, &count)))
> + goto cleanup;
> +
> + if (count != 4)
> + continue;
This leaks tokens.
> +
> + prop_name = tokens[1];
> +
> + if (STREQ(prop_name, "free") || STREQ(prop_name, "size") ||
> + STREQ(prop_name, "allocated")) {
> + unsigned long long value;
> + if (virStrToLong_ull(tokens[2], NULL, 10, &value) < 0)
> + goto cleanup;
> +
> + if (STREQ(prop_name, "free"))
> + pool->def->available = value;
> + else if (STREQ(prop_name, "size"))
> + pool->def->capacity = value;
> + else if (STREQ(prop_name, "allocated"))
> + pool->def->allocation = value;
> + }
> + }
> +
> + /* Obtain a list of volumes */
> + if (virStorageBackendZFSFindVols(pool) < 0)
> + goto cleanup;
> +
> + cleanup:
> + virCommandFree(cmd);
> + virStringFreeList(lines);
> + VIR_FREE(zpool_props);
> +
> + return 0;
> +}
> +
> +
> +static int
> +virStorageBackendZFSCreateVol(virConnectPtr conn ATTRIBUTE_UNUSED,
> + virStoragePoolObjPtr pool,
> + virStorageVolDefPtr vol)
> +{
> + virCommandPtr cmd = NULL;
> + int ret = -1;
> +
> + vol->type = VIR_STORAGE_VOL_BLOCK;
> +
> + if (vol->target.path != NULL) {
> + /* A target path passed to CreateVol has no meaning */
> + VIR_FREE(vol->target.path);
> + }
> +
> + if (virAsprintf(&vol->target.path, "/dev/zvol/%s/%s",
> + pool->def->source.name, vol->name) == -1)
> + return -1;
> +
> + /**
> + * $ zfs create -o volmode=dev -V 10240K test/volname
> + *
> + * -o volmode=dev -- we want to get volumes exposed as cdev
> + * devices. If we don't specify that zfs
> + * will lookup vfs.zfs.vol.mode sysctl value
> + * -V -- tells to create a volume with the specified size
> + */
> + cmd = virCommandNewArgList(ZFS, "create", "-o", "volmode=dev",
> + "-V", NULL);
> + virCommandAddArgFormat(cmd, "%lluK",
> + VIR_DIV_UP(vol->target.capacity, 1024));
> + virCommandAddArgFormat(cmd, "%s/%s",
> + pool->def->source.name, vol->name);
> +
> + if (virCommandRun(cmd, NULL) < 0)
> + goto cleanup;
> +
> + if (virAsprintf(&vol->key, "%s/%s",
> + pool->def->source.name, vol->name) == -1)
> + goto cleanup;
I think we should fill out the key before trying to create it.
Also, is source.name/vol.name unique enough, wouldn't the full target.path be
better?
Jan
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