[PATCH v2 20/20] scsi: target: Add block PR support to iblock.

Mike Christie
2022-08-09T00:07:45Z

This adds support for the block PR callouts to target_core_iblock. This
patch doesn't attempt to implement the entire spec because there's no way
support it all like SPEC_I_PT and ALL_TG_PT. This only supports
exporting the iblock device from one path on the local target.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
drivers/target/target_core_iblock.c | 292 +++++++++++++++++++++++++++-
1 file changed, 287 insertions(+), 5 deletions(-)

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 5db7318b4822..caf6958dd75d 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -23,13 +23,16 @@
#include <linux/file.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
+#include <linux/pr.h>
#include <scsi/scsi_proto.h>
+#include <scsi/scsi_block_pr.h>
#include <asm/unaligned.h>

#include <target/target_core_base.h>
#include <target/target_core_backend.h>

#include "target_core_iblock.h"
+#include "target_core_pr.h"

#define IBLOCK_MAX_BIO_PER_TASK 32 /* max # of bios to submit at a time */
#define IBLOCK_BIO_POOL_SIZE 128
@@ -310,7 +313,7 @@ static unsigned long long iblock_emulate_read_cap_with_block_size(
return blocks_long;
}

-static void iblock_complete_cmd(struct se_cmd *cmd)
+static void iblock_complete_cmd(struct se_cmd *cmd, blk_status_t blk_status)
{
struct iblock_req *ibr = cmd->priv;
u8 status;
@@ -318,7 +321,9 @@ static void iblock_complete_cmd(struct se_cmd *cmd)
if (!refcount_dec_and_test(&ibr->pending))
return;

- if (atomic_read(&ibr->ib_bio_err_cnt))
+ if (blk_status == BLK_STS_NEXUS)
+ status = SAM_STAT_RESERVATION_CONFLICT;
+ else if (atomic_read(&ibr->ib_bio_err_cnt))
status = SAM_STAT_CHECK_CONDITION;
else
status = SAM_STAT_GOOD;
@@ -331,6 +336,7 @@ static void iblock_bio_done(struct bio *bio)
{
struct se_cmd *cmd = bio->bi_private;
struct iblock_req *ibr = cmd->priv;
+ blk_status_t blk_status = bio->bi_status;

if (bio->bi_status) {
pr_err("bio error: %p, err: %d\n", bio, bio->bi_status);
@@ -343,7 +349,7 @@ static void iblock_bio_done(struct bio *bio)

bio_put(bio);

- iblock_complete_cmd(cmd);
+ iblock_complete_cmd(cmd, blk_status);
}

static struct bio *iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num,
@@ -759,7 +765,7 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,

if (!sgl_nents) {
refcount_set(&ibr->pending, 1);
- iblock_complete_cmd(cmd);
+ iblock_complete_cmd(cmd, BLK_STS_OK);
return 0;
}

@@ -817,7 +823,7 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
}

iblock_submit_bios(&list);
- iblock_complete_cmd(cmd);
+ iblock_complete_cmd(cmd, BLK_STS_OK);
return 0;

fail_put_bios:
@@ -829,6 +835,279 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}

+static sense_reason_t iblock_execute_pr_out(struct se_cmd *cmd, u8 sa, u64 key,
+ u64 sa_key, u8 type, bool aptpl,
+ bool all_tg_pt, bool spec_i_pt)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+ struct block_device *bdev = ib_dev->ibd_bd;
+ const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
+ blk_status_t blk_stat = 0;
+ int ret;
+
+ if (!ops) {
+ pr_err("Block device does not support pr_ops but iblock device has been configured for PR passthrough.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ switch (sa) {
+ case PRO_REGISTER_AND_MOVE:
+ pr_err("PRO_REGISTER_AND_MOVE is not supported by iblock PR passthrough.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ case PRO_REPLACE_LOST_RESERVATION:
+ pr_err("PRO_REPLACE_LOST_RESERVATION is not supported by iblock PR passthrough.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ case PRO_REGISTER:
+ case PRO_REGISTER_AND_IGNORE_EXISTING_KEY:
+ if (!ops->pr_register) {
+ pr_err("block device does not support pr_register.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ /*
+ * We only support one target port. We don't know the target
+ * port config at this level and the block layer has a
+ * different view.
+ */
+ if (spec_i_pt || all_tg_pt) {
+ pr_err("SPC-3 PR: SPEC_I_PT and ALL_TG_PT are not supported by PR passthrough.\n");
+
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ /* The block layer pr ops always enables aptpl */
+ if (!aptpl)
+ pr_info("APTPL not set by initiator, but will be used.\n");
+
+ ret = ops->pr_register(bdev, key, sa_key,
+ sa == PRO_REGISTER ? 0 : PR_FL_IGNORE_KEY,
+ &blk_stat);
+ break;
+ case PRO_RESERVE:
+ if (!ops->pr_reserve) {
+ pr_err("block_device does not support pr_reserve.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ ret = ops->pr_reserve(bdev, key, scsi_pr_type_to_block(type), 0,
+ &blk_stat);
+ break;
+ case PRO_CLEAR:
+ if (!ops->pr_clear) {
+ pr_err("block_device does not support pr_clear.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ ret = ops->pr_clear(bdev, key, &blk_stat);
+ break;
+ case PRO_PREEMPT:
+ case PRO_PREEMPT_AND_ABORT:
+ if (!ops->pr_clear) {
+ pr_err("block_device does not support pr_preempt.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ ret = ops->pr_preempt(bdev, key, sa_key,
+ scsi_pr_type_to_block(type),
+ sa == PRO_PREEMPT ? false : true,
+ &blk_stat);
+ break;
+ case PRO_RELEASE:
+ if (!ops->pr_clear) {
+ pr_err("block_device does not support pr_pclear.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ ret = ops->pr_release(bdev, key, scsi_pr_type_to_block(type),
+ &blk_stat);
+ break;
+ default:
+ pr_err("Unknown PERSISTENT_RESERVE_OUT SA: 0x%02x\n", sa);
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ if (!ret)
+ return TCM_NO_SENSE;
+ else if (blk_stat == BLK_STS_NEXUS)
+ return TCM_RESERVATION_CONFLICT;
+ else
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+}
+
+static void iblock_pr_report_caps(unsigned char *param_data)
+{
+ u16 len = 8;
+
+ put_unaligned_be16(len, &param_data[0]);
+ /*
+ * When using the pr_ops passthrough method we only support exporting
+ * the device through one target port because from the backend module
+ * level we can't see the target port config. As a result we only
+ * support registration directly from the I_T nexus the cmd is sent
+ * through and do not set ATP_C here.
+ *
+ * The block layer pr_ops do not support passing in initiators so
+ * we don't set SIP_C here.
+ */
+ /* PTPL_C: Persistence across Target Power Loss bit */
+ param_data[2] |= 0x01;
+ /*
+ * We are filling in the PERSISTENT RESERVATION TYPE MASK below, so
+ * set the TMV: Task Mask Valid bit.
+ */
+ param_data[3] |= 0x80;
+ /*
+ * Change ALLOW COMMANDs to 0x20 or 0x40 later from Table 166
+ */
+ param_data[3] |= 0x10; /* ALLOW COMMANDs field 001b */
+ /*
+ * PTPL_A: Persistence across Target Power Loss Active bit. The block
+ * layer pr ops always enables this so report it active.
+ */
+ param_data[3] |= 0x01;
+ /*
+ * Setup the PERSISTENT RESERVATION TYPE MASK from Table 212 spc4r37.
+ */
+ param_data[4] |= 0x80; /* PR_TYPE_EXCLUSIVE_ACCESS_ALLREG */
+ param_data[4] |= 0x40; /* PR_TYPE_EXCLUSIVE_ACCESS_REGONLY */
+ param_data[4] |= 0x20; /* PR_TYPE_WRITE_EXCLUSIVE_REGONLY */
+ param_data[4] |= 0x08; /* PR_TYPE_EXCLUSIVE_ACCESS */
+ param_data[4] |= 0x02; /* PR_TYPE_WRITE_EXCLUSIVE */
+ param_data[5] |= 0x01; /* PR_TYPE_EXCLUSIVE_ACCESS_ALLREG */
+}
+
+static int iblock_pr_read_keys(struct se_cmd *cmd, unsigned char *param_data)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+ struct block_device *bdev = ib_dev->ibd_bd;
+ const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
+ int i, ret, len, paths, data_offset;
+ struct pr_keys *keys;
+
+ if (!ops) {
+ pr_err("Block device does not support pr_ops but iblock device has been configured for PR passthrough.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ if (!ops->pr_read_keys) {
+ pr_err("Block device does not support read_keys.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ /*
+ * We don't know what's under us, but dm-multipath will register every
+ * path with the same key, so start off with enough space for 16 paths.
+ */
+ paths = 16;
+retry:
+ len = 8 * paths;
+ keys = kzalloc(sizeof(*keys) + len, GFP_KERNEL);
+ if (!keys)
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+ ret = ops->pr_read_keys(bdev, keys, len, NULL);
+ if (!ret) {
+ if (keys->num_keys > paths) {
+ kfree(keys);
+ paths *= 2;
+ goto retry;
+ }
+ } else if (ret) {
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto free_keys;
+ }
+
+ ret = TCM_NO_SENSE;
+
+ put_unaligned_be32(keys->generation, &param_data[0]);
+ if (!keys->num_keys) {
+ put_unaligned_be32(0, &param_data[4]);
+ goto free_keys;
+ }
+
+ put_unaligned_be32(8 * keys->num_keys, &param_data[4]);
+
+ data_offset = 8;
+ for (i = 0; i < keys->num_keys; i++) {
+ if (data_offset + 8 > cmd->data_length)
+ break;
+
+ put_unaligned_be64(keys->keys[i], &param_data[data_offset]);
+ data_offset += 8;
+ }
+
+free_keys:
+ kfree(keys);
+ return ret;
+}
+
+static int iblock_pr_read_reservation(struct se_cmd *cmd,
+ unsigned char *param_data)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+ struct block_device *bdev = ib_dev->ibd_bd;
+ const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
+ struct pr_held_reservation rsv;
+
+ if (!ops) {
+ pr_err("Block device does not support pr_ops but iblock device has been configured for PR passthrough.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ if (!ops->pr_read_reservation) {
+ pr_err("Block device does not support read_keys.\n");
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ if (ops->pr_read_reservation(bdev, &rsv, NULL))
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+ put_unaligned_be32(rsv.generation, &param_data[0]);
+ if (!block_pr_type_to_scsi(rsv.type)) {
+ put_unaligned_be32(0, &param_data[4]);
+ return TCM_NO_SENSE;
+ }
+
+ put_unaligned_be32(16, &param_data[4]);
+
+ if (cmd->data_length < 16)
+ return TCM_NO_SENSE;
+ put_unaligned_be64(rsv.key, &param_data[8]);
+
+ if (cmd->data_length < 22)
+ return TCM_NO_SENSE;
+ param_data[21] = block_pr_type_to_scsi(rsv.type);
+
+ return TCM_NO_SENSE;
+}
+
+static sense_reason_t iblock_execute_pr_in(struct se_cmd *cmd, u8 sa,
+ unsigned char *param_data)
+{
+ sense_reason_t ret = TCM_NO_SENSE;
+
+ switch (sa) {
+ case PRI_REPORT_CAPABILITIES:
+ iblock_pr_report_caps(param_data);
+ break;
+ case PRI_READ_KEYS:
+ ret = iblock_pr_read_keys(cmd, param_data);
+ break;
+ case PRI_READ_RESERVATION:
+ ret = iblock_pr_read_reservation(cmd, param_data);
+ break;
+ case PRI_READ_FULL_STATUS:
+ default:
+ pr_err("Unknown PERSISTENT_RESERVE_IN SA: 0x%02x\n", sa);
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ return ret;
+}
+
static sector_t iblock_get_blocks(struct se_device *dev)
{
struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
@@ -883,6 +1162,8 @@ static struct exec_cmd_ops iblock_exec_cmd_ops = {
.execute_sync_cache = iblock_execute_sync_cache,
.execute_write_same = iblock_execute_write_same,
.execute_unmap = iblock_execute_unmap,
+ .execute_pr_out = iblock_execute_pr_out,
+ .execute_pr_in = iblock_execute_pr_in,
};

static sense_reason_t
@@ -899,6 +1180,7 @@ static bool iblock_get_write_cache(struct se_device *dev)
static const struct target_backend_ops iblock_ops = {
.name = "iblock",
.inquiry_prod = "IBLOCK",
+ .transport_flags_changeable = TRANSPORT_FLAG_PASSTHROUGH_PGR,
.inquiry_rev = IBLOCK_VERSION,
.owner = THIS_MODULE,
.attach_hba = iblock_attach_hba,
--
2.18.2