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scsi: target: add emulate_pr backstore attr to toggle PR support 

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>
hifive-unleashed-5.1
David Disseldorp 2018-11-07 14:11:07 +01:00 committed by Martin K. Petersen
parent 8d0bb86e2c
commit b49d6f7885
5 changed files with 44 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/target/target_core_configfs.c
View File

@ -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;

13
drivers/target/target_core_device.c
View File

@ -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;
@ -1158,6 +1159,18 @@ passthrough_parse_cdb(struct se_cmd *cmd,
return TCM_NO_SENSE;
}
/*
* 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

2
drivers/target/target_core_pr.c
View File

@ -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;

8
drivers/target/target_core_spc.c
View File

@ -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];

3
include/target/target_core_base.h
View File

@ -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;