[lvm-devel] [PATCH 7/8] Add lvm_lv_get_property() generic function to obtain value of any lv property.

[Petr Rockai]

Dave Wysochanski <dwysocha at redhat.com> writes:

> Add a generic LV property function to lvm2app, similar to VG function.
> Return lvm_property_value and require caller to check 'is_valid' flag
> and lvm_errno() for API error.
Same as the previous one.

> Signed-off-by: Dave Wysochanski <dwysocha at redhat.com>
Reviewed-by: Petr Rockai <prockai at redhat.com>

> diff --git a/lib/report/properties.c b/lib/report/properties.c
> index 8f9272c..c08ddfd 100644
> --- a/lib/report/properties.c
> +++ b/lib/report/properties.c
> @@ -267,6 +267,12 @@ static int _get_property(const void *obj, struct lvm_property_type *prop,
>  	return 1;
>  }
>  
> +int lv_get_property(const struct logical_volume *lv,
> +		    struct lvm_property_type *prop)
> +{
> +	return _get_property(lv, prop, LVS);
> +}
> +
>  int vg_get_property(const struct volume_group *vg,
>  		    struct lvm_property_type *prop)
>  {
> diff --git a/lib/report/properties.h b/lib/report/properties.h
> index db4ae51..18e5ab9 100644
> --- a/lib/report/properties.h
> +++ b/lib/report/properties.h
> @@ -32,6 +32,8 @@ struct lvm_property_type {
>  	int (*set) (void *obj, struct lvm_property_type *prop);
>  };
>  
> +int lv_get_property(const struct logical_volume *lv,
> +		    struct lvm_property_type *prop);
>  int vg_get_property(const struct volume_group *vg,
>  		    struct lvm_property_type *prop);
>  int pv_get_property(const struct physical_volume *pv,
> diff --git a/liblvm/lvm2app.h b/liblvm/lvm2app.h
> index ed22ed9..e90adf8 100644
> --- a/liblvm/lvm2app.h
> +++ b/liblvm/lvm2app.h
> @@ -1030,6 +1030,44 @@ const char *lvm_lv_get_name(const lv_t lv);
>  uint64_t lvm_lv_get_size(const lv_t lv);
>  
>  /**
> + * Get the value of a LV property
> + *
> + * \memberof lv_t
> + *
> + * \param   lv
> + * Logical volume handle.
> + *
> + * \param   name
> + * Name of property to query.  See lvs man page for full list of properties
> + * that may be queried.
> + *
> + * The memory allocated for a string property value is tied to the vg_t
> + * handle and will be released when lvm_vg_close() is called.
> + *
> + * Example:
> + *      lvm_property_value v;
> + *      char *prop_name = "seg_count";
> + *
> + *      v = lvm_lv_get_property(lv, prop_name);
> + *      if (lvm_errno(libh) || !v.is_valid) {
> + *           // handle error
> + *           printf("Invalid property name or unable to query"
> + *                  "'%s'.\n", prop_name);
> + *           return;
> + *      }
> + *      if (v.is_string)
> + *           printf(", value = %s\n", v.value.string);
> + *	else
> + *           printf(", value = %"PRIu64"\n", v.value.integer);
> + *
> + * \return
> + * lvm_property_value structure that will contain the current
> + * value of the property.  Caller should check lvm_errno() as well
> + * as 'is_valid' flag before using the value.
> + */
> +struct lvm_property_value lvm_lv_get_property(const lv_t lv, const char *name);
> +
> +/**
>   * Get the current activation state of a logical volume.
>   *
>   * \memberof lv_t
> diff --git a/liblvm/lvm_lv.c b/liblvm/lvm_lv.c
> index 7bdafe0..cef87f5 100644
> --- a/liblvm/lvm_lv.c
> +++ b/liblvm/lvm_lv.c
> @@ -48,6 +48,11 @@ const char *lvm_lv_get_name(const lv_t lv)
>  			       NAME_LEN+1);
>  }
>  
> +struct lvm_property_value lvm_lv_get_property(const lv_t lv, const char *name)
> +{
> +	return get_property(NULL, NULL, lv, name);
> +}
> +
>  uint64_t lvm_lv_is_active(const lv_t lv)
>  {
>  	struct lvinfo info;

Yours,
   Petr.