[libvirt] [PATCH 7/7] storage: Guess the parent if it's not specified for vHBA

[John Ferlan]

On 03/25/2013 12:43 PM, Osier Yang wrote:
> This finds the parent for vHBA by iterating over all the HBA
> which supports vport_ops capability on the host, and return
> the first one which is online, not saturated (vports in use
> is less than max_vports).
> ---
>  src/libvirt_private.syms           |  1 +
>  src/storage/storage_backend_scsi.c | 10 ++--
>  src/util/virutil.c                 | 93 ++++++++++++++++++++++++++++++++++++++
>  src/util/virutil.h                 |  2 +
>  4 files changed, 102 insertions(+), 4 deletions(-)
> 
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 3df7632..932a448 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1850,6 +1850,7 @@ virFileStripSuffix;
>  virFileUnlock;
>  virFileWaitForDevices;
>  virFileWriteStr;
> +virFindFCHostCapableVport;
>  virFindFileInPath;
>  virFormatIntDecimal;
>  virGetDeviceID;
> diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c
> index 0bb4e70..b1ff127 100644
> --- a/src/storage/storage_backend_scsi.c
> +++ b/src/storage/storage_backend_scsi.c
> @@ -658,10 +658,12 @@ createVport(virStoragePoolSourceAdapter adapter)
>                                adapter.data.fchost.wwpn))
>          return 0;
>  
> -    if (!adapter.data.fchost.parent) {
> -        virReportError(VIR_ERR_XML_ERROR, "%s",
> -                       _("'parent' for vHBA must be specified"));
> -        return -1;
> +    if (!adapter.data.fchost.parent &&
> +        !(adapter.data.fchost.parent = virFindFCHostCapableVport(NULL))) {
> +         virReportError(VIR_ERR_XML_ERROR, "%s",
> +                       _("'parent' for vHBA not specified, and "
> +                         "cannot find one on this host"));
> +         return -1;
>      }
>  
>      if (getHostNumber(adapter.data.fchost.parent, &parent_host) < 0)
> diff --git a/src/util/virutil.c b/src/util/virutil.c
> index a8b9962..55d807e 100644
> --- a/src/util/virutil.c
> +++ b/src/util/virutil.c
> @@ -3670,6 +3670,92 @@ cleanup:
>      VIR_FREE(wwpn_buf);
>      return ret;
>  }
> +
> +# define PORT_STATE_ONLINE "Online"
> +
> +/* virFindFCHostCapableVport:
> + *
> + * Iterate over the sysfs and find out the first online HBA which
> + * supports vport, and not saturated,.
> + */
> +char *
> +virFindFCHostCapableVport(const char *sysfs_prefix)
> +{
> +    const char *prefix = sysfs_prefix ? sysfs_prefix : SYSFS_FC_HOST_PATH;
> +    DIR *dir = NULL;
> +    struct dirent *entry = NULL;
> +    char *max_vports = NULL;
> +    char *vports = NULL;
> +    char *state = NULL;
> +    char *ret = NULL;
> +
> +    if (!(dir = opendir(prefix))) {
> +        virReportSystemError(errno,
> +                             _("Failed to opendir path '%s'"),
> +                             prefix);
> +        return NULL;
> +    }
> +
> +    while ((entry = readdir(dir))) {
> +        unsigned int host;
> +        char *p = NULL;
> +
> +        if (entry->d_name[0] == '.')
> +            continue;
> +
> +        p = entry->d_name + strlen("host");

Assumes all entries are prefixed by "host", right? Thus should anything
that is not be filtered like the ".", "..", and hidden files are above?

> +        if (virStrToLong_ui(p, NULL, 10, &host) == -1) {
> +            VIR_DEBUG("Failed to parse host number from '%s'",
> +                      entry->d_name);
> +            continue;
> +        }
> +
> +        if (!virIsCapableVport(NULL, host))
> +            continue;
> +
> +        if (virReadFCHost(NULL, host, "port_state", &state) < 0) {
> +             VIR_DEBUG("Failed to read port_state for host%d", host);
> +             continue;
> +        }
> +
> +        /* Skip the not online FC host */
> +        if (!STREQ(state, PORT_STATE_ONLINE)) {

s/!STREQ/STRNEQ/ ??

> +            VIR_FREE(state);
> +            continue;
> +        }
> +        VIR_FREE(state);
> +
> +        if (virReadFCHost(NULL, host, "max_npiv_vports", &max_vports) < 0) {
> +             VIR_DEBUG("Failed to read max_npiv_vports for host%d", host);
> +             continue;
> +        }
> +
> +        if (virReadFCHost(NULL, host, "npiv_vports_inuse", &vports) < 0) {
> +             VIR_DEBUG("Failed to read npiv_vports_inuse for host%d", host);
> +             VIR_FREE(max_vports);
> +             continue;
> +        }
> +
> +        /* Compare from the strings directly, instead of converting
> +         * the strings to integers first
> +         */
> +        if ((strlen(max_vports) >= strlen(vports)) ||
> +            ((strlen(max_vports) == strlen(vports)) &&
> +             strcmp(max_vports, vports) > 0)) {
> +            ret = strdup(entry->d_name);
> +            goto cleanup;
> +        }
> +
> +        VIR_FREE(max_vports);
> +        VIR_FREE(vports);
> +    }
> +
> +cleanup:
> +    closedir(dir);
> +    VIR_FREE(max_vports);
> +    VIR_FREE(vports);
> +    return ret;
> +}
>  #else
>  int
>  virReadFCHost(const char *sysfs_prefix ATTRIBUTE_UNUSED,
> @@ -3715,4 +3801,11 @@ virGetFCHostNameByWWN(const char *sysfs_prefix ATTRIBUTE_UNUSED,
>      return NULL;
>  }
>  
> +char *
> +virFindFCHostCapableVport(const char *sysfs_prefix ATTRIBUTE_UNUSED)
> +{
> +    virReportSystemError(ENOSYS, "%s", _("Not supported on this platform"));
> +    return NULL;
> +}
> +
>  #endif /* __linux__ */
> diff --git a/src/util/virutil.h b/src/util/virutil.h
> index d134034..cde4218 100644
> --- a/src/util/virutil.h
> +++ b/src/util/virutil.h
> @@ -322,4 +322,6 @@ char *virGetFCHostNameByWWN(const char *sysfs_prefix,
>                              const char *wwpn)
>      ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3);
>  
> +char *virFindFCHostCapableVport(const char *sysfs_prefix);
> +
>  #endif /* __VIR_UTIL_H__ */
> 

ACK - NOTE that I still haven't seen anywhere "fc_host" would be
necessary from patch 5/7.

John