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



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;
+}
-- 
1.7.11.7


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