target_core_alua: Referrals infrastructure

Add infrastructure for referrals.

v2 changes:

 - Fix unsigned long long division in core_alua_state_lba_dependent on
   32-bit  (Fengguang + Chen + Hannes)
 - Fix compile warning in core_alua_state_lba_dependent (nab)
 - Convert segment_* + sectors variables in core_alua_state_lba_dependent
   to u64 (Hannes)

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index 01f0c71..0843c8f 100644 (file)
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -57,6 +57,75 @@ static LIST_HEAD(lu_gps_list);
 
 struct t10_alua_lu_gp *default_lu_gp;
 
+/*
+ * REPORT REFERRALS
+ *
+ * See sbc3r35 section 5.23
+ */
+sense_reason_t
+target_emulate_report_referrals(struct se_cmd *cmd)
+{
+       struct se_device *dev = cmd->se_dev;
+       struct t10_alua_lba_map *map;
+       struct t10_alua_lba_map_member *map_mem;
+       unsigned char *buf;
+       u32 rd_len = 0, off;
+
+       if (cmd->data_length < 4) {
+               pr_warn("REPORT REFERRALS allocation length %u too"
+                       " small\n", cmd->data_length);
+               return TCM_INVALID_CDB_FIELD;
+       }
+
+       buf = transport_kmap_data_sg(cmd);
+       if (!buf)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       off = 4;
+       spin_lock(&dev->t10_alua.lba_map_lock);
+       if (list_empty(&dev->t10_alua.lba_map_list)) {
+               spin_unlock(&dev->t10_alua.lba_map_lock);
+               transport_kunmap_data_sg(cmd);
+
+               return TCM_UNSUPPORTED_SCSI_OPCODE;
+       }
+
+       list_for_each_entry(map, &dev->t10_alua.lba_map_list,
+                           lba_map_list) {
+               int desc_num = off + 3;
+               int pg_num;
+
+               off += 4;
+               put_unaligned_be64(map->lba_map_first_lba, &buf[off]);
+               off += 8;
+               put_unaligned_be64(map->lba_map_last_lba, &buf[off]);
+               off += 8;
+               rd_len += 20;
+               pg_num = 0;
+               list_for_each_entry(map_mem, &map->lba_map_mem_list,
+                                   lba_map_mem_list) {
+                       buf[off++] = map_mem->lba_map_mem_alua_state & 0x0f;
+                       off++;
+                       buf[off++] = (map_mem->lba_map_mem_alua_pg_id >> 8) & 0xff;
+                       buf[off++] = (map_mem->lba_map_mem_alua_pg_id & 0xff);
+                       rd_len += 4;
+                       pg_num++;
+               }
+               buf[desc_num] = pg_num;
+       }
+       spin_unlock(&dev->t10_alua.lba_map_lock);
+
+       /*
+        * Set the RETURN DATA LENGTH set in the header of the DataIN Payload
+        */
+       put_unaligned_be16(rd_len, &buf[2]);
+
+       transport_kunmap_data_sg(cmd);
+
+       target_complete_cmd(cmd, GOOD);
+       return 0;
+}
+
 /*
  * REPORT_TARGET_PORT_GROUPS
  *
@@ -391,6 +460,81 @@ static inline int core_alua_state_nonoptimized(
        return 0;
 }
 
+static inline int core_alua_state_lba_dependent(
+       struct se_cmd *cmd,
+       struct t10_alua_tg_pt_gp *tg_pt_gp,
+       u8 *alua_ascq)
+{
+       struct se_device *dev = cmd->se_dev;
+       u64 segment_size, segment_mult, sectors, lba;
+
+       /* Only need to check for cdb actually containing LBAs */
+       if (!(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB))
+               return 0;
+
+       spin_lock(&dev->t10_alua.lba_map_lock);
+       segment_size = dev->t10_alua.lba_map_segment_size;
+       segment_mult = dev->t10_alua.lba_map_segment_multiplier;
+       sectors = cmd->data_length / dev->dev_attrib.block_size;
+
+       lba = cmd->t_task_lba;
+       while (lba < cmd->t_task_lba + sectors) {
+               struct t10_alua_lba_map *cur_map = NULL, *map;
+               struct t10_alua_lba_map_member *map_mem;
+
+               list_for_each_entry(map, &dev->t10_alua.lba_map_list,
+                                   lba_map_list) {
+                       u64 start_lba, last_lba;
+                       u64 first_lba = map->lba_map_first_lba;
+
+                       if (segment_mult) {
+                               u64 tmp = lba;
+                               start_lba = sector_div(tmp, segment_size * segment_mult);
+
+                               last_lba = first_lba + segment_size - 1;
+                               if (start_lba >= first_lba &&
+                                   start_lba <= last_lba) {
+                                       lba += segment_size;
+                                       cur_map = map;
+                                       break;
+                               }
+                       } else {
+                               last_lba = map->lba_map_last_lba;
+                               if (lba >= first_lba && lba <= last_lba) {
+                                       lba = last_lba + 1;
+                                       cur_map = map;
+                                       break;
+                               }
+                       }
+               }
+               if (!cur_map) {
+                       spin_unlock(&dev->t10_alua.lba_map_lock);
+                       *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                       return 1;
+               }
+               list_for_each_entry(map_mem, &cur_map->lba_map_mem_list,
+                                   lba_map_mem_list) {
+                       if (map_mem->lba_map_mem_alua_pg_id !=
+                           tg_pt_gp->tg_pt_gp_id)
+                               continue;
+                       switch(map_mem->lba_map_mem_alua_state) {
+                       case ALUA_ACCESS_STATE_STANDBY:
+                               spin_unlock(&dev->t10_alua.lba_map_lock);
+                               *alua_ascq = ASCQ_04H_ALUA_TG_PT_STANDBY;
+                               return 1;
+                       case ALUA_ACCESS_STATE_UNAVAILABLE:
+                               spin_unlock(&dev->t10_alua.lba_map_lock);
+                               *alua_ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE;
+                               return 1;
+                       default:
+                               break;
+                       }
+               }
+       }
+       spin_unlock(&dev->t10_alua.lba_map_lock);
+       return 0;
+}
+
 static inline int core_alua_state_standby(
        struct se_cmd *cmd,
        unsigned char *cdb,
@@ -588,6 +732,9 @@ target_alua_state_check(struct se_cmd *cmd)
        case ALUA_ACCESS_STATE_TRANSITION:
                ret = core_alua_state_transition(cmd, cdb, &alua_ascq);
                break;
+       case ALUA_ACCESS_STATE_LBA_DEPENDENT:
+               ret = core_alua_state_lba_dependent(cmd, tg_pt_gp, &alua_ascq);
+               break;
        /*
         * OFFLINE is a secondary ALUA target port group access state, that is
         * handled above with struct se_port->sep_tg_pt_secondary_offline=1
@@ -650,6 +797,11 @@ core_alua_check_transition(int state, int valid, int *primary)
                        goto not_supported;
                *primary = 1;
                break;
+       case ALUA_ACCESS_STATE_LBA_DEPENDENT:
+               if (!(valid & ALUA_LBD_SUP))
+                       goto not_supported;
+               *primary = 1;
+               break;
        case ALUA_ACCESS_STATE_OFFLINE:
                /*
                 * OFFLINE state is defined as a secondary target port
@@ -685,6 +837,8 @@ static char *core_alua_dump_state(int state)
                return "Active/Optimized";
        case ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED:
                return "Active/NonOptimized";
+       case ALUA_ACCESS_STATE_LBA_DEPENDENT:
+               return "LBA Dependent";
        case ALUA_ACCESS_STATE_STANDBY:
                return "Standby";
        case ALUA_ACCESS_STATE_UNAVAILABLE:

diff --git a/drivers/target/target_core_alua.h b/drivers/target/target_core_alua.h
index 1a152cd..47950cd 100644 (file)
--- a/drivers/target/target_core_alua.h
+++ b/drivers/target/target_core_alua.h
@@ -13,12 +13,13 @@
 /*
  * ASYMMETRIC ACCESS STATE field
  *
- * from spc4r17 section 6.27 Table 245
+ * from spc4r36j section 6.37 Table 307
  */
 #define ALUA_ACCESS_STATE_ACTIVE_OPTIMIZED     0x0
 #define ALUA_ACCESS_STATE_ACTIVE_NON_OPTIMIZED 0x1
 #define ALUA_ACCESS_STATE_STANDBY              0x2
 #define ALUA_ACCESS_STATE_UNAVAILABLE          0x3
+#define ALUA_ACCESS_STATE_LBA_DEPENDENT                0x4
 #define ALUA_ACCESS_STATE_OFFLINE              0xe
 #define ALUA_ACCESS_STATE_TRANSITION           0xf
 
@@ -88,6 +89,7 @@ extern struct kmem_cache *t10_alua_tg_pt_gp_mem_cache;
 
 extern sense_reason_t target_emulate_report_target_port_groups(struct se_cmd *);
 extern sense_reason_t target_emulate_set_target_port_groups(struct se_cmd *);
+extern sense_reason_t target_emulate_report_referrals(struct se_cmd *);
 extern int core_alua_check_nonop_delay(struct se_cmd *);
 extern int core_alua_do_port_transition(struct t10_alua_tg_pt_gp *,
                                struct se_device *, struct se_port *,

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index a1c23d1..e0a47f5 100644 (file)
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -2054,6 +2054,13 @@ static ssize_t target_core_alua_tg_pt_gp_store_attr_alua_access_state(
                        " transition while TPGS_IMPLICIT_ALUA is disabled\n");
                return -EINVAL;
        }
+       if (tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICIT_ALUA &&
+           new_state == ALUA_ACCESS_STATE_LBA_DEPENDENT) {
+               /* LBA DEPENDENT is only allowed with implicit ALUA */
+               pr_err("Unable to process implicit configfs ALUA transition"
+                      " while explicit ALUA management is enabled\n");
+               return -EINVAL;
+       }
 
        ret = core_alua_do_port_transition(tg_pt_gp, dev,
                                        NULL, NULL, new_state, 0);
@@ -2188,7 +2195,7 @@ SE_DEV_ALUA_SUPPORT_STATE_SHOW(lba_dependent,
                               tg_pt_gp_alua_supported_states, ALUA_LBD_SUP);
 SE_DEV_ALUA_SUPPORT_STATE_STORE(lba_dependent,
                                tg_pt_gp_alua_supported_states, ALUA_LBD_SUP);
-SE_DEV_ALUA_TG_PT_ATTR(alua_support_lba_dependent, S_IRUGO | S_IWUSR);
+SE_DEV_ALUA_TG_PT_ATTR(alua_support_lba_dependent, S_IRUGO);
 
 SE_DEV_ALUA_SUPPORT_STATE_SHOW(unavailable,
                               tg_pt_gp_alua_supported_states, ALUA_U_SUP);

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index dbd78a1..88b4fb2 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -1439,6 +1439,8 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
        spin_lock_init(&dev->t10_pr.aptpl_reg_lock);
        INIT_LIST_HEAD(&dev->t10_alua.tg_pt_gps_list);
        spin_lock_init(&dev->t10_alua.tg_pt_gps_lock);
+       INIT_LIST_HEAD(&dev->t10_alua.lba_map_list);
+       spin_lock_init(&dev->t10_alua.lba_map_lock);
 
        dev->t10_wwn.t10_dev = dev;
        dev->t10_alua.t10_dev = dev;

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 52ae54e..6863dbe 100644 (file)
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -33,7 +33,7 @@
 
 #include "target_core_internal.h"
 #include "target_core_ua.h"
-
+#include "target_core_alua.h"
 
 static sense_reason_t
 sbc_emulate_readcapacity(struct se_cmd *cmd)
@@ -731,6 +731,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
                case SAI_READ_CAPACITY_16:
                        cmd->execute_cmd = sbc_emulate_readcapacity_16;
                        break;
+               case SAI_REPORT_REFERRALS:
+                       cmd->execute_cmd = target_emulate_report_referrals;
+                       break;
                default:
                        pr_err("Unsupported SA: 0x%02x\n",
                                cmd->t_task_cdb[1] & 0x1f);

diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 39054d9..f9889fd 100644 (file)
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -476,6 +476,11 @@ spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
        /* If WriteCache emulation is enabled, set V_SUP */
        if (spc_check_dev_wce(dev))
                buf[6] = 0x01;
+       /* If an LBA map is present set R_SUP */
+       spin_lock(&cmd->se_dev->t10_alua.lba_map_lock);
+       if (!list_empty(&dev->t10_alua.lba_map_list))
+               buf[8] = 0x10;
+       spin_unlock(&cmd->se_dev->t10_alua.lba_map_lock);
        return 0;
 }
 
@@ -634,6 +639,20 @@ spc_emulate_evpd_b2(struct se_cmd *cmd, unsigned char *buf)
        return 0;
 }
 
+/* Referrals VPD page */
+static sense_reason_t
+spc_emulate_evpd_b3(struct se_cmd *cmd, unsigned char *buf)
+{
+       struct se_device *dev = cmd->se_dev;
+
+       buf[0] = dev->transport->get_device_type(dev);
+       buf[3] = 0x0c;
+       put_unaligned_be32(dev->t10_alua.lba_map_segment_size, &buf[8]);
+       put_unaligned_be32(dev->t10_alua.lba_map_segment_size, &buf[12]);
+
+       return 0;
+}
+
 static sense_reason_t
 spc_emulate_evpd_00(struct se_cmd *cmd, unsigned char *buf);
 
@@ -648,6 +667,7 @@ static struct {
        { .page = 0xb0, .emulate = spc_emulate_evpd_b0 },
        { .page = 0xb1, .emulate = spc_emulate_evpd_b1 },
        { .page = 0xb2, .emulate = spc_emulate_evpd_b2 },
+       { .page = 0xb3, .emulate = spc_emulate_evpd_b3 },
 };
 
 /* supported vital product data pages */

diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 66d42ed..0a4edfe 100644 (file)
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -155,6 +155,7 @@ enum scsi_timeouts {
 /* values for service action in */
 #define        SAI_READ_CAPACITY_16  0x10
 #define SAI_GET_LBA_STATUS    0x12
+#define SAI_REPORT_REFERRALS  0x13
 /* values for VARIABLE_LENGTH_CMD service action codes
  * see spc4r17 Section D.3.5, table D.7 and D.8 */
 #define VLC_SA_RECEIVE_CREDENTIAL 0x1800

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 6c80015..1ba19a4 100644 (file)
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -247,10 +247,28 @@ typedef enum {
 
 struct se_cmd;
 
+struct t10_alua_lba_map_member {
+       struct list_head lba_map_mem_list;
+       int lba_map_mem_alua_state;
+       int lba_map_mem_alua_pg_id;
+};
+
+struct t10_alua_lba_map {
+       u64 lba_map_first_lba;
+       u64 lba_map_last_lba;
+       struct list_head lba_map_list;
+       struct list_head lba_map_mem_list;
+};
+
 struct t10_alua {
        /* ALUA Target Port Group ID */
        u16     alua_tg_pt_gps_counter;
        u32     alua_tg_pt_gps_count;
+       /* Referrals support */
+       spinlock_t lba_map_lock;
+       u32     lba_map_segment_size;
+       u32     lba_map_segment_multiplier;
+       struct list_head lba_map_list;
        spinlock_t tg_pt_gps_lock;
        struct se_device *t10_dev;
        /* Used for default ALUA Target Port Group */