From a97901405259e395fa7522ffa0d7dece20575568 Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@suse.de>
Date: Wed, 7 Nov 2018 14:11:07 +0100
Subject: [PATCH] scsi: target: add emulate_pr backstore attr to toggle PR
support
References: bsc#1091405
Git-commit: b49d6f7885306ee636d5c1af52170f3069ccf5f7
Patch-mainline: v4.21-rc1
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 <ddiss@suse.de>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
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(-)
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 1aeaec3908f7..733232a29228 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,
@@ -1478,6 +1482,9 @@ 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");
@@ -1618,12 +1625,14 @@ 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,
@@ -1631,7 +1640,8 @@ 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",
@@ -1643,7 +1653,8 @@ 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");
@@ -1689,7 +1700,8 @@ 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 e8dd6da164b2..98de8ea0a58b 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -806,6 +806,7 @@ 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;
@@ -1170,6 +1171,18 @@ 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 f0fc99457f8b..812a11103822 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -4361,6 +4361,8 @@ 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 922fa15bee2e..82c46617ab55 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -1290,6 +1290,14 @@ 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 47b995c6e285..a6b35fabdde8 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -88,6 +88,8 @@
#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 */
@@ -666,6 +668,7 @@ 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