Re: [PATCH RFC] storage: ZFS support

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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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