[PATCH 3.12 072/155] target: Allow AllRegistrants to re-RESERVE existing reservation

From: Jiri Slaby
Date: Tue Apr 07 2015 - 09:16:14 EST

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit ae450e246e8540300699480a3780a420a028b73f upstream.

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@xxxxxxxxx>
Cc: Ilias Tsitsimpis <i.tsitsimpis@xxxxxxxxx>
Cc: Lee Duncan <lduncan@xxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
drivers/target/target_core_pr.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 13a4836765ea..98e2f02b48f6 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -2297,6 +2297,7 @@ core_scsi3_pro_reserve(struct se_cmd *cmd, int type, int scope, u64 res_key)
pr_res_holder = dev->dev_pr_res_holder;
if (pr_res_holder) {
+ int pr_res_type = pr_res_holder->pr_res_type;
* From spc4r17 Section 5.7.9: Reserving:
@@ -2307,7 +2308,9 @@ core_scsi3_pro_reserve(struct se_cmd *cmd, int type, int scope, u64 res_key)
* the logical unit, then the command shall be completed with
- if (pr_res_holder != pr_reg) {
+ if ((pr_res_holder != pr_reg) &&
+ (pr_res_type != PR_TYPE_WRITE_EXCLUSIVE_ALLREG) &&
struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;
pr_err("SPC-3 PR: Attempted RESERVE from"
" [%s]: %s while reservation already held by"

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