In setup_full_feature_phase, iscsid calls into the kernel via start_conn, then sets all the relevant device states to "running" via session_online_devs. This second step is redundant since start_conn will set the device states to running. Moreover, it can cause tasks to hang forever: between start_conn and session_online_devs, the kernel could detect another conn error and block the session again, which quiesces the device queues. Setting the device state to "running" via sysfs kicks off a rescan, and if the device queue is quiesced, the rescan will hang. The iscsid kernel stacktrace looks like the following:
[<0>] blk_execute_rq+0x11c/0x170 [<0>] __scsi_execute+0x108/0x270 [<0>] scsi_vpd_inquiry+0x6d/0xc0 [<0>] scsi_get_vpd_size+0x33/0x70 [<0>] scsi_get_vpd_buf+0x25/0xb0 [<0>] scsi_attach_vpd+0x33/0x1a0 [<0>] scsi_rescan_device+0x2a/0x90 [<0>] store_state_field+0x1b0/0x250 [<0>] kernfs_fop_write_iter+0x130/0x1c0 [<0>] new_sync_write+0x10c/0x190 [<0>] vfs_write+0x218/0x2a0 [<0>] ksys_write+0x59/0xd0 [<0>] do_syscall_64+0x3a/0x80 [<0>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 Since iscsid is responsible for recovery from the second conn error but it is stuck, the relevant device queues will remain quiesced forever. Tasks attempting I/O on these queues will thus also get stuck. For these two reasons, remove the call to session_online_devs in setup_full_feature_phase. Signed-off-by: Uday Shankar <[email protected]> --- usr/initiator.c | 1 - 1 file changed, 1 deletion(-) diff --git a/usr/initiator.c b/usr/initiator.c index 56bf38b..6cbdcba 100644 --- a/usr/initiator.c +++ b/usr/initiator.c @@ -1068,7 +1068,6 @@ setup_full_feature_phase(iscsi_conn_t *conn) } else { session->notify_qtask = NULL; - session_online_devs(session->hostno, session->id); mgmt_ipc_write_rsp(c->qtask, ISCSI_SUCCESS); log_warning("connection%d:%d is operational after recovery " "(%d attempts)", session->id, conn->id, -- 2.25.1 -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/open-iscsi/20220811234028.3848279-1-ushankar%40purestorage.com.
