After a PGR command is processed in the kernel, is it possible for the
user mode to be notified with the command so that the user mode has a
chance to do its part of PGR processing. Below is one use case of it.
Suppose two TCMU servers are set up as an active/passive cluster for
high availability. An initiator's PGR command is sent to the active
server only. But the active server's user mode would like the passive
server to know about the PGR command also and sync up its configfs
state with the active server. This is to make sure that when the
active server dies, the passive server can take over with the correct
PGR state.
Thanks,
-Shie-rei
On Thu, Mar 30, 2017 at 7:47 AM, Bryant G. Ly
<bryantly@xxxxxxxxxxxxxxxxxx> wrote:
> This adds PGR support for just TCMU, since tcmu doesn't
> have the necessary IT_NEXUS info to process PGR in userspace,
> so have those commands be processed in kernel.
>
> Signed-off-by: Bryant G. Ly <bryantly@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/target/target_core_configfs.c | 10 +++++-----
> drivers/target/target_core_device.c | 27 +++++++++++++++++++++++++++
> drivers/target/target_core_pr.c | 2 +-
> drivers/target/target_core_pscsi.c | 3 ++-
> include/target/target_core_backend.h | 1 +
> 5 files changed, 36 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
> index 38b5025..edfb098 100644
> --- a/drivers/target/target_core_configfs.c
> +++ b/drivers/target/target_core_configfs.c
> @@ -1366,7 +1366,7 @@ 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->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
> + if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
> return sprintf(page, "Passthrough\n");
>
> spin_lock(&dev->dev_reservation_lock);
> @@ -1506,7 +1506,7 @@ static ssize_t target_pr_res_type_show(struct config_item *item, char *page)
> {
> struct se_device *dev = pr_to_dev(item);
>
> - if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
> + if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
> return sprintf(page, "SPC_PASSTHROUGH\n");
> else if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)
> return sprintf(page, "SPC2_RESERVATIONS\n");
> @@ -1519,7 +1519,7 @@ 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)
> + if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
> return 0;
>
> return sprintf(page, "APTPL Bit Status: %s\n",
> @@ -1531,7 +1531,7 @@ 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)
> + if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
> return 0;
>
> return sprintf(page, "Ready to process PR APTPL metadata..\n");
> @@ -1577,7 +1577,7 @@ 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)
> + if (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 c754ae3..83c0d77 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -1045,6 +1045,7 @@ passthrough_parse_cdb(struct se_cmd *cmd,
> sense_reason_t (*exec_cmd)(struct se_cmd *cmd))
> {
> unsigned char *cdb = cmd->t_task_cdb;
> + struct se_device *dev = cmd->se_dev;
>
> /*
> * Clear a lun set in the cdb if the initiator talking to use spoke
> @@ -1076,6 +1077,32 @@ passthrough_parse_cdb(struct se_cmd *cmd,
> return TCM_NO_SENSE;
> }
>
> + /*
> + * 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.
> + */
> + if (!(dev->transport->transport_flags &
> + TRANSPORT_FLAG_PASSTHROUGH_PGR)) {
> + if (cdb[0] == PERSISTENT_RESERVE_IN) {
> + cmd->execute_cmd = target_scsi3_emulate_pr_in;
> + return TCM_NO_SENSE;
> + }
> + if (cdb[0] == PERSISTENT_RESERVE_OUT) {
> + cmd->execute_cmd = target_scsi3_emulate_pr_out;
> + return TCM_NO_SENSE;
> + }
> +
> + if (cdb[0] == RELEASE || cdb[0] == RELEASE_10) {
> + cmd->execute_cmd = target_scsi2_reservation_release;
> + return TCM_NO_SENSE;
> + }
> + if (cdb[0] == RESERVE || cdb[0] == RESERVE_10) {
> + cmd->execute_cmd = target_scsi2_reservation_reserve;
> + return TCM_NO_SENSE;
> + }
> + }
> +
> /* Set DATA_CDB flag for ops that should have it */
> switch (cdb[0]) {
> case READ_6:
> diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
> index e180511..129ca57 100644
> --- a/drivers/target/target_core_pr.c
> +++ b/drivers/target/target_core_pr.c
> @@ -4147,7 +4147,7 @@ target_check_reservation(struct se_cmd *cmd)
> return 0;
> if (dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE)
> return 0;
> - if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
> + if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH_PGR)
> return 0;
>
> spin_lock(&dev->dev_reservation_lock);
> diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
> index 94cda79..8943a62 100644
> --- a/drivers/target/target_core_pscsi.c
> +++ b/drivers/target/target_core_pscsi.c
> @@ -1081,7 +1081,8 @@ static const struct target_backend_ops pscsi_ops = {
> .name = "pscsi",
> .owner = THIS_MODULE,
> .transport_flags = TRANSPORT_FLAG_PASSTHROUGH |
> - TRANSPORT_FLAG_PASSTHROUGH_ALUA,
> + TRANSPORT_FLAG_PASSTHROUGH_ALUA |
> + TRANSPORT_FLAG_PASSTHROUGH_PGR,
> .attach_hba = pscsi_attach_hba,
> .detach_hba = pscsi_detach_hba,
> .pmode_enable_hba = pscsi_pmode_enable_hba,
> diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
> index 1b0f447..e475531 100644
> --- a/include/target/target_core_backend.h
> +++ b/include/target/target_core_backend.h
> @@ -10,6 +10,7 @@
> * backend module.
> */
> #define TRANSPORT_FLAG_PASSTHROUGH_ALUA 0x2
> +#define TRANSPORT_FLAG_PASSTHROUGH_PGR 0x4
>
> struct request_queue;
> struct scatterlist;
> --
> 2.5.4 (Apple Git-61)
>
> --
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