[PATCH 6/8] Add lvm_pv_get_property() generic function to obtain value of any pv property.

Dave Wysochanski <[email protected]> writes:

> Add a generic PV 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.

If you go with my suggestion from previous patch about "including"
lvm_errno in is_valid, the docs in this patch will need to be changed
accordingly.

> Signed-off-by: Dave Wysochanski <[email protected]>
Reviewed-by: Petr Rockai <[email protected]>

Other than that, good to go.

> diff --git a/liblvm/lvm2app.h b/liblvm/lvm2app.h
> index 8b244fc..ed22ed9 100644
> --- a/liblvm/lvm2app.h
> +++ b/liblvm/lvm2app.h
> @@ -1240,6 +1240,44 @@ uint64_t lvm_pv_get_size(const pv_t pv);
>  uint64_t lvm_pv_get_free(const pv_t pv);
>  
>  /**
> + * Get the value of a PV property
> + *
> + * \memberof pv_t
> + *
> + * \param   pv
> + * Physical volume handle.
> + *
> + * \param   name
> + * Name of property to query.  See pvs 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 value;
> + *      char *prop_name = "pv_mda_count";
> + *
> + *      v = lvm_pv_get_property(pv, 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_pv_get_property(const pv_t pv, const char *name);
> +
> +/**
>   * Resize physical volume to new_size bytes.
>   *
>   * \memberof pv_t
> diff --git a/liblvm/lvm_pv.c b/liblvm/lvm_pv.c
> index 0b6b6b1..efdccb5 100644
> --- a/liblvm/lvm_pv.c
> +++ b/liblvm/lvm_pv.c
> @@ -16,6 +16,7 @@
>  #include "lvm2app.h"
>  #include "metadata.h"
>  #include "lvm-string.h"
> +#include "lvm_misc.h"
>  
>  const char *lvm_pv_get_uuid(const pv_t pv)
>  {
> @@ -48,6 +49,11 @@ uint64_t lvm_pv_get_free(const pv_t pv)
>  	return (uint64_t) SECTOR_SIZE * pv_free(pv);
>  }
>  
> +struct lvm_property_value lvm_pv_get_property(const pv_t pv, const char *name)
> +{
> +	return get_property(pv, NULL, NULL, name);
> +}
> +
>  int lvm_pv_resize(const pv_t pv, uint64_t new_size)
>  {
>  	/* FIXME: add pv resize code here */