c0cp: determine optimal unit size automatically

Determine the optimal unit size automatically based on the
buffer size specified by user and the parity configuration of
the pool where the object is written to. For example:

```
$ ./c0cp 2176 128000 /tmp/128K 128
.c0cprc/client-22
pool=<6f00000000000001:6bf> unit_size=64KB
success! object created.
/tmp/128K 131072
c0cp success
```

c0appz.c

@@ -101,7 +101,7 @@ struct clovis_aio_op {
  */
 static char *trim(char *str);
 static int open_entity(struct m0_clovis_entity *entity);
-static int create_object(struct m0_uint128 id);
+static int create_object(struct m0_uint128 id, uint64_t bsz);
 static int read_data_from_file(FILE *fp, struct m0_bufvec *data, int bsz);
 static int write_data_to_file(FILE *fp, struct m0_bufvec *data, int bsz);
 
@@ -122,7 +122,7 @@ static void clovis_aio_failed_cb(struct m0_clovis_op *op);
  * GLOBAL VARIABLES
  ******************************************************************************
  */
-unsigned unit_size = 4;
+unsigned unit_size = 0;
 int perf=0;							/* performance option 			*/
 extern int qos_total_weight; 		/* total bytes read or written 	*/
 extern pthread_mutex_t qos_lock;	/* lock  qos_total_weight 		*/
@@ -604,10 +604,9 @@ int c0appz_rmach_bulk_cutoff(struct m0_rpc_link *link, uint32_t *bulk_cutoff)
 
 static int c0appz_spiel_prepare(struct m0_spiel *spiel)
 {
-	struct m0_reqh *reqh;
+	struct m0_reqh *reqh = &clovis_instance->m0c_reqh;
 	int             rc;
 
-	reqh = &clovis_instance->m0c_reqh;
 	rc = m0_spiel_init(spiel, reqh);
 	if (rc != 0) {
 		fprintf(stderr, "error! spiel initialisation failed.\n");
@@ -658,7 +657,7 @@ struct m0_rpc_link * c0appz_isc_rpc_link_get(struct m0_fid *svc_fid)
 int c0appz_isc_api_register(const char *libpath)
 {
 	int                     rc;
-	struct m0_reqh         *reqh;
+	struct m0_reqh         *reqh = &clovis_instance->m0c_reqh;
 	struct m0_confc        *confc;
 	struct m0_conf_root    *root;
 	struct m0_conf_process *proc;
@@ -670,7 +669,7 @@ int c0appz_isc_api_register(const char *libpath)
 		fprintf(stderr, "error! spiel initialization failed");
 		return rc;
 	}
-	reqh = &clovis_instance->m0c_reqh;
+
 	confc = m0_reqh2confc(reqh);
 	rc = m0_confc_root_open(confc, &root);
 	if (rc != 0) {
@@ -912,13 +911,16 @@ int c0appz_init(int idx)
 	/* set to Sage cluster specific values */
 	clovis_conf.cc_tm_recv_queue_min_len = 64;
 	clovis_conf.cc_max_rpc_msg_size      = 65536;
-	lid = m0_clovis_obj_unit_size_to_layout_id(unit_size * 1024);
-	if (lid == 0) {
-		fprintf(stderr, "invalid unit size %u, it should be: "
-			"power of 2, >= 4 and <= 4096\n", unit_size);
-		return -EINVAL;
+	clovis_conf.cc_layout_id             = 0;
+	if (unit_size) {
+		lid = m0_clovis_obj_unit_size_to_layout_id(unit_size * 1024);
+		if (lid == 0) {
+			fprintf(stderr, "invalid unit size %u, it should be: "
+				"power of 2, >= 4 and <= 4096\n", unit_size);
+			return -EINVAL;
+		}
+		clovis_conf.cc_layout_id = lid;
 	}
-	clovis_conf.cc_layout_id = lid;
 
 	/* IDX_MERO */
 	clovis_conf.cc_idx_service_id   = M0_CLOVIS_IDX_DIX;
@@ -1045,7 +1047,7 @@ static int open_entity(struct m0_clovis_entity *entity)
  * 1  - object already exists.
  * -1 - failed, due to errors.
  */
-int c0appz_cr(uint64_t idhi, uint64_t idlo)
+int c0appz_cr(uint64_t idhi, uint64_t idlo, uint64_t bsz)
 {
 	int rc=0;
 	struct m0_uint128 id={0};
@@ -1055,7 +1057,7 @@ int c0appz_cr(uint64_t idhi, uint64_t idlo)
 	id.u_lo = idlo;
 
 	/* create object */
-	rc = create_object(id);
+	rc = create_object(id, bsz);
 	if (rc > 0) {
 		fprintf(stderr,"%s: object already exists!\n", __func__);
 		return rc;
@@ -1076,25 +1078,39 @@ int c0appz_cr(uint64_t idhi, uint64_t idlo)
  * 1  - object already exists.
  * -1 - failed, due to errors.
  */
-static int create_object(struct m0_uint128 id)
+static int create_object(struct m0_uint128 id, uint64_t bsz)
 {
-	int                  rc;
-	struct m0_clovis_obj obj = {};
-	struct m0_clovis_op *ops[1] = {NULL};
+	int                     rc;
+	unsigned                lid;
+	struct m0_reqh         *reqh = &clovis_instance->m0c_reqh;
+	struct m0_pool_version *pver;
+	struct m0_clovis_op    *ops[1] = {NULL};
+	struct m0_clovis_obj    obj = {};
 
-	m0_clovis_obj_init(&obj, &clovis_uber_realm, &id,
-			   m0_clovis_layout_id(clovis_instance));
+	rc = m0_pool_version_get(reqh->rh_pools, pool_fid, &pver);
+	if (rc != 0) {
+		fprintf(stderr, "%s: m0_pool_version_get() failed: rc=%d\n",
+			__func__, rc);
+		return -1;
+	}
+
+	if (unit_size)
+		lid = m0_clovis_layout_id(clovis_instance);
+	else
+		lid = m0_layout_find_by_buffsize(&reqh->rh_ldom, &pver->pv_id,
+						 bsz);
+
+	printf("pool="FID_F" unit_size=%dKB\n", FID_P(&pver->pv_pool->po_id),
+	       m0_clovis_obj_layout_id_to_unit_size(lid) / 1024);
+
+	m0_clovis_obj_init(&obj, &clovis_uber_realm, &id, lid);
 
 	rc = open_entity(&obj.ob_entity);
 	if (rc == 0) {
 		/* object exists, return 1 */
 		return 1;
 	}
 
-	/* print pool ID */
-	if (pool_fid)
-		printf("pool: "FID_F"\n", FID_P(pool_fid));
-
 	/* create object */
 	rc = m0_clovis_entity_create(pool_fid, &obj.ob_entity, &ops[0]);
 	if (rc != 0) {

c0appz.h

@@ -31,9 +31,9 @@ extern unsigned unit_size; /* in KiBs, default 4 */
 
 int c0appz_init(int idx);
 int c0appz_free(void);
-int c0appz_cr(uint64_t idhi,uint64_t idlo);
-int c0appz_rm(uint64_t idhi,uint64_t idlo);
-int c0appz_ex(uint64_t idhi,uint64_t idlo);
+int c0appz_cr(uint64_t idhi, uint64_t idlo, uint64_t bsz);
+int c0appz_rm(uint64_t idhi, uint64_t idlo);
+int c0appz_ex(uint64_t idhi, uint64_t idlo);
 
 int c0appz_ct(uint64_t idhi,uint64_t idlo,char *filename,uint64_t bsz,uint64_t cnt);
 int c0appz_cp(uint64_t idhi,uint64_t idlo,char *filename,uint64_t bsz,uint64_t cnt);

c0cp.c

@@ -160,7 +160,7 @@ int main(int argc, char **argv)
 
 	/* create object */
 	c0appz_timein();
-	rc = c0appz_cr(idh, idl);
+	rc = c0appz_cr(idh, idl, bsz);
 	if (rc < 0 || (rc != 0 && !force)) {
 		if (rc < 0)
 			fprintf(stderr,"%s(): object create failed: rc=%d\n",

c0cp_async.c

@@ -128,7 +128,7 @@ int main(int argc, char **argv)
 
 	/* create object */
 	c0appz_timein();
-	if((c0appz_cr(idh,idl)!=0)&&(!force)){
+	if (c0appz_cr(idh, idl, bsz) != 0 && !force) {
 		fprintf(stderr,"error! create object failed.\n");
 		truncate64(fname,fs.st_size);
 		stat64(fname,&fs);

help_c0cp.txt

@@ -8,14 +8,15 @@ idl - Mero fid low
 bsz - Clovis block size (in KiBs)
 
 options are:
-	-u | unit size (in KiBs, default 4),
-	   | must be power of 2, >= 4 and <= 4096
 	-f | force
 	-p | performance
 	-c | contiguous mode. 
 	   | -c <n> write <n> contiguous copies of the file. 
 	-x | pool ID. 
 	   | -x <n> creates the object in pool with ID <n>. 
+	-u | unit size (in KiBs), must be power of 2, >= 4 and <= 4096.
+           | By default, determined automatically based on the bsz and
+           | parity configuration of the pool.
 
  The -f option forces rewriting on an object if that object already exists. 
  It creates a new object if the object does not exist.