diff mbox

[v6,19/33] target: Avoid that LUN reset sporadically triggers data corruption

Message ID 20170215002612.14566-20-bart.vanassche@sandisk.com (mailing list archive)
State Superseded
Headers show

Commit Message

Bart Van Assche Feb. 15, 2017, 12:25 a.m. UTC
If on an initiator system a LUN reset is issued while I/O is in
progress with queue depth > 1, avoid that data corruption occurs
as follows:
- The initiator submits a READ (a).
- The initiator submits a LUN reset before READ (a) completes.
- The target responds that the LUN reset succeeded after READ (a)
  has been marked as CMD_T_COMPLETE and before .queue_status() has
  been called.
- The initiator receives the LUN reset response and frees the
  tag used by READ (a).
- The initiator submits READ (b) and reuses the tag of READ (a).
- The initiator receives the response for READ (a) and interprets
  this as a completion for READ (b).
- The initiator receives the completion for READ (b) and discards

With the SRP initiator and target drivers and when running fio
concurrently with sg_reset -d it only takes a few minutes to
reproduce this.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Fixes: commit febe562c20df ("target: Fix LUN_RESET active I/O handling for ACK_KREF")
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: David Disseldorp <ddiss@suse.de>
Cc: <stable@vger.kernel.org>
 drivers/target/target_core_tmr.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
diff mbox


diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 32ea7c61d6ac..16e748eb32d2 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -109,7 +109,7 @@  static int target_check_cdb_and_preempt(struct list_head *list,
 	return 1;
-static bool __target_check_io_state(struct se_cmd *se_cmd,
+static bool __target_check_io_state(struct se_cmd *se_cmd, u32 skip_flags,
 				    struct se_session *tmr_sess, int tas)
 	struct se_session *sess = se_cmd->se_sess;
@@ -127,7 +127,7 @@  static bool __target_check_io_state(struct se_cmd *se_cmd,
 	 * long as se_cmd->cmd_kref is still active unless zero.
-	if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
+	if (se_cmd->transport_state & (skip_flags | CMD_T_FABRIC_STOP)) {
 		pr_debug("Attempted to abort io tag: %llu already complete or"
 			" fabric stop, skipping\n", se_cmd->tag);
@@ -182,7 +182,8 @@  void core_tmr_abort_task(
 		printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 			se_cmd->se_tfo->get_fabric_name(), ref_tag);
-		if (!__target_check_io_state(se_cmd, se_sess, 0))
+		if (!__target_check_io_state(se_cmd, CMD_T_COMPLETE, se_sess,
+					     0))
@@ -354,7 +355,7 @@  static void core_tmr_drain_state_list(
-		rc = __target_check_io_state(cmd, tmr_sess, tas);
+		rc = __target_check_io_state(cmd, 0, tmr_sess, tas);
 		if (!rc)