[PATCH V4] lvm2app: Add thin and thin pool lv creation

[Tony Asleson <tasleson@redhat.com>]

Looked over the patch and have the following comments:

The patch has a warning when building.  In the function lvm_lv_thinpool,
the variable lwmb is unused and can be removed.  The added functions
don't verify all the parameters.  We can't protect against everything,
but I still think it would be good to check for NULL on the pointer
arguments and non-zero length on strings?

Thanks,
Tony



On 03/19/2013 12:24 PM, M. Mohan Kumar wrote:
> From: "M. Mohan Kumar" <mohan@in.ibm.com>
> 
> Add thin and thin pool lv creation support to lvm library
> 
> Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
> ---
> Changes from V3:
> * Added paramater to specify metadata size, flags
> 
> Changes from V2:
> * Specify percentage for low water mark threshold instead of number of
>   blocks
> 
> Changes from previous version:
> * Add support to specify data block size and low water mark thresold for
> newly created thin pool.
> 
>  lib/metadata/lv_manip.c          |   2 +-
>  lib/metadata/metadata-exported.h |   1 +
>  liblvm/lvm2app.h                 |  73 +++++++++++++++++++
>  liblvm/lvm_lv.c                  | 154 +++++++++++++++++++++++++++++++++++++++
>  4 files changed, 229 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
> index c1437eb..4dd5ebf 100644
> --- a/lib/metadata/lv_manip.c
> +++ b/lib/metadata/lv_manip.c
> @@ -4518,7 +4518,7 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg, struct l
>  		first_seg(lv)->chunk_size = lp->chunk_size;
>  		first_seg(lv)->discards = lp->discards;
>  		/* FIXME: use lowwatermark  via lvm.conf global for all thinpools ? */
> -		first_seg(lv)->low_water_mark = 0;
> +		first_seg(lv)->low_water_mark = lp->low_water_mark;
>  	} else if (seg_is_thin_volume(lp)) {
>  		pool_lv = first_seg(lv)->pool_lv;
>  
> diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
> index ffec129..40519f5 100644
> --- a/lib/metadata/metadata-exported.h
> +++ b/lib/metadata/metadata-exported.h
> @@ -617,6 +617,7 @@ struct lvcreate_params {
>  	uint64_t voriginsize; /* snapshot */
>  	uint32_t poolmetadataextents; /* thin pool */
>  	uint64_t poolmetadatasize; /* thin pool */
> +	uint64_t low_water_mark;  /* thin_pool */
>  	struct dm_list *pvh; /* all */
>  
>  	uint32_t permission; /* all */
> diff --git a/liblvm/lvm2app.h b/liblvm/lvm2app.h
> index 93a78c3..0f8e39c 100644
> --- a/liblvm/lvm2app.h
> +++ b/liblvm/lvm2app.h
> @@ -1400,6 +1400,79 @@ int lvm_lv_resize(const lv_t lv, uint64_t new_size);
>   */
>  lv_t lvm_lv_snapshot(const lv_t lv, const char *snap_name, uint64_t max_snap_size);
>  
> +
> +#define THIN_FL_DISCARDS_IGNORE          0x0001
> +#define THIN_FL_DISCARDS_NO_PASSDOWN     0x0010
> +#define THIN_FL_SKIP_ZERO                0x0100
> +
> +/**
> + * Create a thinpool in a given VG
> + *
> + * \param   vg
> + * Volume Group handle.
> + *
> + * \param   pool_name
> + * Name of the pool.
> + *
> + * \param   size
> + * size of the pool
> + *
> + * \param   chunk_size
> + * data block size of the pool
> + * Default value is DEFAULT_THIN_POOL_CHUNK_SIZE * 2 when 0 passed as chunk_size
> + * DM_THIN_MIN_DATA_BLOCK_SIZE < chunk_size < DM_THIN_MAX_DATA_BLOCK_SIZE
> + *
> + * \param  threshold in percentage
> + * When percentage of free blocks in the pool reaches <= this thresold a dm
> + * event is sent. For example if threshold is specified 25, an dm event will be
> + * generated when the percentage of free blocks goes <= 25%.
> + *
> + * Note: when 0 is passed as threshold, an event will be generated only when all
> + * blocks are consumed in the pool.
> + *
> + * \param meta_size
> + * Size of thin pool's metadata logical volume. Allowed range is 2MB-16GB.
> + * Default value (ie if 0) pool size / pool chunk size * 64
> + *
> + * \param flags
> + * As of now supported flags are
> + * THIN_FL_DISCARDS_IGNORE,
> + * THIN_FL_DISCARDS_NO_PASSDOWN,
> + * THIN_FL_SKIP_ZERO
> + *
> + * If none of Discard related flag passed THIN_DISCARDS_PASSDOWN is enabled.
> + *
> + * \return
> + * Valid lv pointer on success, else NULL on error.
> + *
> + */
> +lv_t lvm_lv_thinpool(const vg_t vg, const char *pool_name, uint64_t size,
> +		     uint32_t chunk_size, uint64_t meta_size, int threshold,
> +		     int flags);
> +
> +/**
> + * Create a thin LV in a given VG & thin pool
> + *
> + * \param   vg
> + * Volume Group handle.
> + *
> + * \param   pool_name
> + * Name of the pool.
> + *
> + * \param lvname
> + * Name of the LV to create
> + *
> + * \param   size
> + * Size of logical volume
> + *
> + * \return
> + * Valid lv pointer on success, else NULL on error.
> + *
> + */
> +
> +lv_t lvm_lv_thin(const vg_t vg, const char *pool_name, const char *lvname,
> +		uint64_t size);
> +
>  /************************** physical volume handling ************************/
>  
>  /**
> diff --git a/liblvm/lvm_lv.c b/liblvm/lvm_lv.c
> index 91948a6..d4645f4 100644
> --- a/liblvm/lvm_lv.c
> +++ b/liblvm/lvm_lv.c
> @@ -350,3 +350,157 @@ lv_t lvm_lv_snapshot(const lv_t lv, const char *snap_name, uint64_t max_snap_siz
>  		return NULL;
>  	return (lv_t) lvl->lv;
>  }
> +
> +/* Set defaults for thin pool specific LV parameters */
> +static void _lv_set_pool_params(struct lvcreate_params *lp,
> +				vg_t vg, const char *pool,
> +				uint64_t extents, uint64_t meta_size)
> +{
> +	_lv_set_default_params(lp, vg, NULL, extents);
> +
> +	lp->pool = pool;
> +
> +	lp->create_thin_pool = 1;
> +	lp->segtype = get_segtype_from_string(vg->cmd, "thin-pool");
> +	lp->stripes = 1;
> +
> +	if (!meta_size) {
> +		lp->poolmetadatasize = extents * vg->extent_size /
> +			(lp->chunk_size * (SECTOR_SIZE / 64));
> +		while ((lp->poolmetadatasize >
> +			(2 * DEFAULT_THIN_POOL_OPTIMAL_SIZE / SECTOR_SIZE)) &&
> +		       lp->chunk_size < DM_THIN_MAX_DATA_BLOCK_SIZE) {
> +			lp->chunk_size <<= 1;
> +			lp->poolmetadatasize >>= 1;
> +	         }
> +	} else
> +		lp->poolmetadatasize = meta_size;
> +
> +	if (lp->poolmetadatasize % vg->extent_size)
> +		lp->poolmetadatasize +=
> +			vg->extent_size - lp->poolmetadatasize % vg->extent_size;
> +
> +	lp->poolmetadataextents =
> +		extents_from_size(vg->cmd, lp->poolmetadatasize / SECTOR_SIZE,
> +						   vg->extent_size);
> +}
> +
> +lv_t lvm_lv_thinpool(const vg_t vg, const char *pool, uint64_t size,
> +		     uint32_t chunk_size, uint64_t meta_size, int threshold,
> +		     int flags)
> +{
> +	struct lvcreate_params lp = { 0 };
> +	uint64_t extents = 0;
> +	struct lv_list *lvl = NULL;
> +	uint64_t lwmb = 0;
> +
> +	if (meta_size > (2 * DEFAULT_THIN_POOL_MAX_METADATA_SIZE)) {
> +		log_error("Invalid metadata size");
> +		return NULL;
> +	}
> +
> +	if (meta_size &&
> +	    meta_size < (2 * DEFAULT_THIN_POOL_MIN_METADATA_SIZE)) {
> +		log_error("Invalid metadata size");
> +		return NULL;
> +	}
> +
> +	if (vg_read_error(vg))
> +		return NULL;
> +
> +	if (!vg_check_write_mode(vg))
> +		return NULL;
> +
> +	if (threshold < 0 || threshold > 100) {
> +		log_error("Invalid threshold, should be between 0-100");
> +		return NULL;
> +	}
> +	if (!(extents = extents_from_size(vg->cmd, size / SECTOR_SIZE,
> +					  vg->extent_size))) {
> +		log_error("Unable to create LV thin pool without size.");
> +		return NULL;
> +	}
> +
> +	if (flags & THIN_FL_DISCARDS_NO_PASSDOWN)
> +		lp.discards = THIN_DISCARDS_NO_PASSDOWN;
> +	else if (flags & THIN_FL_DISCARDS_IGNORE)
> +		lp.discards = THIN_DISCARDS_IGNORE;
> +	else
> +		lp.discards = THIN_DISCARDS_PASSDOWN;
> +
> +	if (chunk_size)
> +		lp.chunk_size = chunk_size;
> +	else
> +		lp.chunk_size = DEFAULT_THIN_POOL_CHUNK_SIZE * 2;
> +
> +	if (lp.chunk_size < DM_THIN_MIN_DATA_BLOCK_SIZE ||
> +	    lp.chunk_size > DM_THIN_MAX_DATA_BLOCK_SIZE) {
> +		log_error("Invalid chunk_size");
> +		return NULL;
> +	}
> +
> +	_lv_set_pool_params(&lp, vg, pool, extents, meta_size);
> +
> +	if (flags & THIN_FL_SKIP_ZERO)
> +		lp.zero = 0;
> +	/*
> +	  threshold specified in percentage, convert that into
> +	  number of blocks
> +	*/
> +	lp.low_water_mark = size / (chunk_size * SECTOR_SIZE) * threshold / 100;
> +	if (!lp.segtype)
> +		return_NULL;
> +	if (!lv_create_single(vg, &lp))
> +		return_NULL;
> +	if (!(lvl = find_lv_in_vg(vg, pool)))
> +		return_NULL;
> +	return (lv_t) lvl->lv;
> +}
> +
> +/* Set defaults for thin LV specific parameters */
> +static void _lv_set_thin_params(struct lvcreate_params *lp,
> +				vg_t vg, const char *pool,
> +				const char *lvname,
> +				uint64_t extents)
> +{
> +	_lv_set_default_params(lp, vg, lvname, extents);
> +
> +	lp->thin = 1;
> +	lp->pool = pool;
> +	lp->segtype = get_segtype_from_string(vg->cmd, "thin");
> +
> +	lp->voriginsize = extents * vg->extent_size;
> +	lp->voriginextents = extents_from_size(vg->cmd, lp->voriginsize,
> +						   vg->extent_size);
> +
> +	lp->stripes = 1;
> +}
> +
> +lv_t lvm_lv_thin(const vg_t vg, const char *pool,
> +		 const char *lvname, uint64_t size)
> +{
> +	struct lvcreate_params lp = { 0 };
> +	uint64_t extents = 0;
> +	struct lv_list *lvl = NULL;
> +
> +	if (vg_read_error(vg))
> +		return NULL;
> +	if (!vg_check_write_mode(vg))
> +		return NULL;
> +
> +	if (!(extents = extents_from_size(vg->cmd, size / SECTOR_SIZE,
> +					  vg->extent_size))) {
> +		log_error("Unable to create thin LV without size.");
> +		return NULL;
> +	}
> +
> +	_lv_set_thin_params(&lp, vg, pool, lvname, extents);
> +
> +	if (!lp.segtype)
> +		return_NULL;
> +	if (!lv_create_single(vg, &lp))
> +		return_NULL;
> +	if (!(lvl = find_lv_in_vg(vg, pool)))
> +		return_NULL;
> +	return (lv_t) lvl->lv;
> +}