The new emulate_pr backstore attribute allows for Persistent Reservation
and SCSI2 RESERVE/RELEASE support to be completely disabled. This can be
useful for scenarios such as:
- Ensuring ATS (Compare & Write) usage on recent VMware ESXi initiators.
- Allowing clustered (e.g. tcm-user) backends to block such requests,
avoiding the multi-node reservation state propagation.
When explicitly disabled, PR and RESERVE/RELEASE requests receive
Invalid Command Operation Code response sense data.
Signed-off-by: David Disseldorp <dd...@suse.de>
---
drivers/target/target_core_configfs.c | 24 ++++++++++++++++++------
drivers/target/target_core_device.c | 13 +++++++++++++
drivers/target/target_core_pr.c | 2 ++
drivers/target/target_core_spc.c | 8 ++++++++
include/target/target_core_base.h | 3 +++
5 files changed, 44 insertions(+), 6 deletions(-)
Changes since v4:
* keep pgr_support attribute independent of emulate_pr
Changes since v3:
* rebase against current mainline
Changes since v2:
* handle target_pr_res_aptpl_metadata_store()
* use common error path for spc_parse_cdb() and passthrough_parse_cdb()
checks
* drop erroneous TRANSPORT_FLAG_PASSTHROUGH_PGR ->
TRANSPORT_FLAG_PASSTHROUGH changes
Changes since v1:
* block Reservation request passthrough when emulate_pr=0
* fix some style issues
* add an emulate_pr check to pgr_support_show()
diff --git a/drivers/target/target_core_configfs.c
b/drivers/target/target_core_configfs.c
index f6b1549f4142..70b9f6755c36 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -532,6 +532,7 @@ DEF_CONFIGFS_ATTRIB_SHOW(emulate_tpu);
DEF_CONFIGFS_ATTRIB_SHOW(emulate_tpws);
DEF_CONFIGFS_ATTRIB_SHOW(emulate_caw);
DEF_CONFIGFS_ATTRIB_SHOW(emulate_3pc);
+DEF_CONFIGFS_ATTRIB_SHOW(emulate_pr);
DEF_CONFIGFS_ATTRIB_SHOW(pi_prot_type);
DEF_CONFIGFS_ATTRIB_SHOW(hw_pi_prot_type);
DEF_CONFIGFS_ATTRIB_SHOW(pi_prot_format);
@@ -592,6 +593,7 @@ static ssize_t _name##_store(struct config_item *item,
const char *page, \
DEF_CONFIGFS_ATTRIB_STORE_BOOL(emulate_fua_write);
DEF_CONFIGFS_ATTRIB_STORE_BOOL(emulate_caw);
DEF_CONFIGFS_ATTRIB_STORE_BOOL(emulate_3pc);
+DEF_CONFIGFS_ATTRIB_STORE_BOOL(emulate_pr);
DEF_CONFIGFS_ATTRIB_STORE_BOOL(enforce_pr_isids);
DEF_CONFIGFS_ATTRIB_STORE_BOOL(is_nonrot);
@@ -1116,6 +1118,7 @@ CONFIGFS_ATTR(, emulate_tpu);
CONFIGFS_ATTR(, emulate_tpws);
CONFIGFS_ATTR(, emulate_caw);
CONFIGFS_ATTR(, emulate_3pc);
+CONFIGFS_ATTR(, emulate_pr);
CONFIGFS_ATTR(, pi_prot_type);
CONFIGFS_ATTR_RO(, hw_pi_prot_type);
CONFIGFS_ATTR(, pi_prot_format);
@@ -1156,6 +1159,7 @@ struct configfs_attribute *sbc_attrib_attrs[] = {
&attr_emulate_tpws,
&attr_emulate_caw,
&attr_emulate_3pc,
+ &attr_emulate_pr,
&attr_pi_prot_type,
&attr_hw_pi_prot_type,
&attr_pi_prot_format,
@@ -1427,6 +1431,9 @@ static ssize_t target_pr_res_holder_show(struct
config_item *item, char *page)
struct se_device *dev = pr_to_dev(item);
int ret;
+ if (!dev->dev_attrib.emulate_pr)
+ return sprintf(page, "SPC_RESERVATIONS_DISABLED\n");
+
if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
return sprintf(page, "Passthrough\n");
@@ -1567,12 +1574,14 @@ static ssize_t target_pr_res_type_show(struct
config_item *item, char *page)
{
struct se_device *dev = pr_to_dev(item);
+ if (!dev->dev_attrib.emulate_pr)
+ return sprintf(page, "SPC_RESERVATIONS_DISABLED\n");
if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
return sprintf(page, "SPC_PASSTHROUGH\n");
- else if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)
+ if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)
return sprintf(page, "SPC2_RESERVATIONS\n");
- else
- return sprintf(page, "SPC3_PERSISTENT_RESERVATIONS\n");
+
+ return sprintf(page, "SPC3_PERSISTENT_RESERVATIONS\n");
}
static ssize_t target_pr_res_aptpl_active_show(struct config_item *item,
@@ -1580,7 +1589,8 @@ static ssize_t target_pr_res_aptpl_active_show(struct
config_item *item,
{
struct se_device *dev = pr_to_dev(item);
- if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
+ if (!dev->dev_attrib.emulate_pr ||
+ (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR))
return 0;
return sprintf(page, "APTPL Bit Status: %s\n",
@@ -1592,7 +1602,8 @@ static ssize_t target_pr_res_aptpl_metadata_show(struct
config_item *item,
{
struct se_device *dev = pr_to_dev(item);
- if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
+ if (!dev->dev_attrib.emulate_pr ||
+ (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR))
return 0;
return sprintf(page, "Ready to process PR APTPL metadata..\n");
@@ -1638,7 +1649,8 @@ static ssize_t target_pr_res_aptpl_metadata_store(struct
config_item *item,
u16 tpgt = 0;
u8 type = 0;
- if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
+ if (!dev->dev_attrib.emulate_pr ||
+ (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR))
return count;
if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)
return count;
diff --git a/drivers/target/target_core_device.c
b/drivers/target/target_core_device.c
index 47b5ef153135..3274a5fa825c 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -805,6 +805,7 @@ struct se_device *target_alloc_device(struct se_hba *hba,
const char *name)
dev->dev_attrib.emulate_tpws = DA_EMULATE_TPWS;
dev->dev_attrib.emulate_caw = DA_EMULATE_CAW;
dev->dev_attrib.emulate_3pc = DA_EMULATE_3PC;
+ dev->dev_attrib.emulate_pr = DA_EMULATE_PR;
dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE0_PROT;
dev->dev_attrib.enforce_pr_isids = DA_ENFORCE_PR_ISIDS;
dev->dev_attrib.force_pr_aptpl = DA_FORCE_PR_APTPL;
@@ -1159,6 +1160,18 @@ passthrough_parse_cdb(struct se_cmd *cmd,
}
/*
+ * With emulate_pr disabled, all reservation requests should fail,
+ * regardless of whether or not TRANSPORT_FLAG_PASSTHROUGH_PGR is set.
+ */
+ if (!dev->dev_attrib.emulate_pr &&
+ ((cdb[0] == PERSISTENT_RESERVE_IN) ||
+ (cdb[0] == PERSISTENT_RESERVE_OUT) ||
+ (cdb[0] == RELEASE || cdb[0] == RELEASE_10) ||
+ (cdb[0] == RESERVE || cdb[0] == RESERVE_10))) {
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
+ /*
* For PERSISTENT RESERVE IN/OUT, RELEASE, and RESERVE we need to
* emulate the response, since tcmu does not have the information
* required to process these commands.
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 10db5656fd5d..91a2927acd36 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -4095,6 +4095,8 @@ target_check_reservation(struct se_cmd *cmd)
return 0;
if (dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE)
return 0;
+ if (!dev->dev_attrib.emulate_pr)
+ return 0;
if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
return 0;
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index f459118bc11b..5c49eb6f4929 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -1281,6 +1281,14 @@ spc_parse_cdb(struct se_cmd *cmd, unsigned int *size)
struct se_device *dev = cmd->se_dev;
unsigned char *cdb = cmd->t_task_cdb;
+ if (!dev->dev_attrib.emulate_pr &&
+ ((cdb[0] == PERSISTENT_RESERVE_IN) ||
+ (cdb[0] == PERSISTENT_RESERVE_OUT) ||
+ (cdb[0] == RELEASE || cdb[0] == RELEASE_10) ||
+ (cdb[0] == RESERVE || cdb[0] == RESERVE_10))) {
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+ }
+
switch (cdb[0]) {
case MODE_SELECT:
*size = cdb[4];
diff --git a/include/target/target_core_base.h
b/include/target/target_core_base.h
index e3bdb0550a59..c15054116b86 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -87,6 +87,8 @@
#define DA_EMULATE_3PC 1
/* No Emulation for PSCSI by default */
#define DA_EMULATE_ALUA 0
+/* Emulate SCSI2 RESERVE/RELEASE and Persistent Reservations by default */
+#define DA_EMULATE_PR 1
/* Enforce SCSI Initiator Port TransportID with 'ISID' for PR */
#define DA_ENFORCE_PR_ISIDS 1
/* Force SPC-3 PR Activate Persistence across Target Power Loss */
@@ -664,6 +666,7 @@ struct se_dev_attrib {
int emulate_tpws;
int emulate_caw;
int emulate_3pc;
+ int emulate_pr;
int pi_prot_format;
enum target_prot_type pi_prot_type;
enum target_prot_type hw_pi_prot_type;
--
2.13.7
