For PGR reservation of type Write Exclusive Access, allow all non
reservation holding I_T nexuses with active registrations to READ
from the device.

This addresses a bug where active registrations that attempted
to READ would result in an reservation conflict.

Signed-off-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Pull SCSI target fixes from Nicholas Bellinger:
 "The highlights this merge window include:

   - Allow target fabric drivers to function as built-in.  (Roland)
   - Fix tcm_loop multi-TPG endpoint nexus bug.  (Hannes)
   - Move per device config_item_type into se_subsystem_api, allowing
     configfs attributes to be defined at module_init time.  (Jerome +
     nab)
   - Convert existing IBLOCK/FILEIO/RAMDISK/PSCSI/TCMU drivers to use
     external configfs attributes.  (nab)
   - A number of iser-target fixes related to active session + network
     portal shutdown stability during extended stress testing.  (Sagi +
     Slava)
   - Dynamic allocation of T10-PI contexts for iser-target, fixing a
     potentially bogus iscsi_np->tpg_np pointer reference in >= v3.14
     code.  (Sagi)
   - iser-target performance + scalability improvements.  (Sagi)
   - Fixes for SPC-4 Persistent Reservation AllRegistrants spec
     compliance.  (Ilias + James + nab)
   - Avoid potential short kern_sendmsg() in iscsi-target for now until
     Al's conversion to use msghdr iteration is merged post -rc1.
     (Viro)

  Also, Sagi has requested a number of iser-target patches (9) that
  address stability issues he's encountered during extended stress
  testing be considered for v3.10.y + v3.14.y code.  Given the amount of
  LOC involved, it will certainly require extra backporting effort.

  Apologies in advance to Greg-KH & Co on this.  Sagi and I will be
  working post-merge to ensure they each get applied correctly"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (53 commits)
  target: Allow AllRegistrants to re-RESERVE existing reservation
  uapi/linux/target_core_user.h: fix headers_install.sh badness
  iscsi-target: Fail connection on short sendmsg writes
  iscsi-target: nullify session in failed login sequence
  target: Avoid dropping AllRegistrants reservation during unregister
  target: Fix R_HOLDER bit usage for AllRegistrants
  iscsi-target: Drop left-over bogus iscsi_np->tpg_np
  iser-target: Fix wc->wr_id cast warning
  iser-target: Remove code duplication
  iser-target: Adjust log levels and prettify some prints
  iser-target: Use debug_level parameter to control logging level
  iser-target: Fix logout sequence
  iser-target: Don't wait for session commands from completion context
  iser-target: Reduce CQ lock contention by batch polling
  iser-target: Introduce isert_poll_budget
  iser-target: Remove an atomic operation from the IO path
  iser-target: Remove redundant call to isert_conn_terminate
  iser-target: Use single CQ for TX and RX
  iser-target: Centralize completion elements to a context
  iser-target: Cast wr_id with uintptr_t instead of unsinged long
  ...

This patch changes core_scsi3_pro_release() logic to allow an
existing AllRegistrants type reservation to be re-reserved by
any registered I_T nexus.

This addresses a issue where AllRegistrants type RESERVE was
receiving RESERVATION_CONFLICT status if dev_pr_res_holder did
not match the same I_T nexus, instead of just returning GOOD
status following spc4r34 Section 5.9.9:

"If the device server receives a PERSISTENT RESERVE OUT command
 with RESERVE service action where the TYPE field and the SCOPE
 field contain the same values as the existing type and scope
 from a persistent reservation holder, it shall not make any
 change to the existing persistent reservation and shall complete
 the command with GOOD status."

Reported-by: Ilias Tsitsimpis <i.tsitsimpis@gmail.com>
Cc: Ilias Tsitsimpis <i.tsitsimpis@gmail.com>
Cc: Lee Duncan <lduncan@suse.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch fixes an issue with AllRegistrants reservations where
an unregister operation by the I_T nexus reservation holder would
incorrectly drop the reservation, instead of waiting until the
last active I_T nexus is unregistered as per SPC-4.

This includes updating __core_scsi3_complete_pro_release() to reset
dev->dev_pr_res_holder with another pr_reg for this special case,
as well as a new 'unreg' parameter to determine when the release
is occuring from an implicit unregister, vs. explicit RELEASE.

It also adds special handling in core_scsi3_free_pr_reg_from_nacl()
to release the left-over pr_res_holder, now that pr_reg is deleted
from pr_reg_list within __core_scsi3_complete_pro_release().

Reported-by: Ilias Tsitsimpis <i.tsitsimpis@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch fixes the usage of R_HOLDER bit for an All Registrants
reservation in READ_FULL_STATUS, where only the registration who
issued RESERVE was being reported as having an active reservation.

It changes core_scsi3_pri_read_full_status() to check ahead of the
list walk of active registrations to see if All Registrants is active,
and if so set R_HOLDER bit and scope/type fields for all active
registrations.

Reported-by: Ilias Tsitsimpis <i.tsitsimpis@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Delete a local array that is only used to be initialized by memset.

A semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
type T;
@@

{
... when any
-T x[...];
<+... when != x
- memset(x,...);
...+>
}
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

SPC-3 defines SERVICE ACTION IN(12), SERVICE_ACTION OUT(12),
SERVICE ACTION OUT(16), and SERVICE ACTION BIDIRECTIONAL.
And READ MEDIA SERIAL NUMBER has long since been deprecated.
So update callers to refer to the new cdb name.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Tested-by: Robert Elliott <elliott@hp.com>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

PREEMPT (and PREEMPT AND ABORT) should return CONFLICT iff a specified
SERVICE ACTION RESERVATION KEY is specified and matches no existing
persistent reservation.

Without this patch, a PREEMPT will return CONFLICT if either all
reservations are held by the initiator (self preemption) or there is
nothing to preempt. According to the spec, both of these cases should
succeed.

Signed-off-by: Steven Allen <steven.allen@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds a force_pr_aptpl device attribute used to force SPC-3 PR
Activate Persistence across Target Power Loss (APTPL) operation.  This
makes PR metadata write-out occur during state change regardless if new
PERSISTENT_RESERVE_OUT CDBs have their APTPL feature bit set.

This is useful during H/A failover in active/passive setups where all PR
state is being re-created on a different node, driven by configfs backend
device + export layout and pre-loaded $DEV/pr/res_aptpl_metadata.

Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>