From: Bharath Ravi <[email protected]> Connection failure processing depends on a daemon being present to (at least) stop the connection and start recovery. This is a problem on a multipath scenario, where if the daemon failed for whatever reason, the SCSI path is never marked as down, multipath won't perform the failover and IO to the device will be forever waiting for that connection to come back.
This patch implements an optional feature in the iscsi module, to perform the connection failure inside the kernel. This way, the failover can happen and pending IO can continue even if the daemon is dead. Once the daemon comes alive again, it can perform recovery procedures if applicable. Co-developed-by: Dave Clausen <[email protected]> Signed-off-by: Dave Clausen <[email protected]> Co-developed-by: Nick Black <[email protected]> Signed-off-by: Nick Black <[email protected]> Co-developed-by: Vaibhav Nagarnaik <[email protected]> Signed-off-by: Vaibhav Nagarnaik <[email protected]> Co-developed-by: Anatol Pomazau <[email protected]> Signed-off-by: Anatol Pomazau <[email protected]> Co-developed-by: Tahsin Erdogan <[email protected]> Signed-off-by: Tahsin Erdogan <[email protected]> Co-developed-by: Frank Mayhar <[email protected]> Signed-off-by: Frank Mayhar <[email protected]> Co-developed-by: Junho Ryu <[email protected]> Signed-off-by: Junho Ryu <[email protected]> Co-developed-by: Khazhismel Kumykov <[email protected]> Signed-off-by: Khazhismel Kumykov <[email protected]> Signed-off-by: Bharath Ravi <[email protected]> Co-developed-by: Gabriel Krisman Bertazi <[email protected]> Signed-off-by: Gabriel Krisman Bertazi <[email protected]> --- drivers/scsi/scsi_transport_iscsi.c | 46 +++++++++++++++++++++++++++++ include/scsi/scsi_transport_iscsi.h | 1 + 2 files changed, 47 insertions(+) diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c index 417b868d8735..7251b2b5b272 100644 --- a/drivers/scsi/scsi_transport_iscsi.c +++ b/drivers/scsi/scsi_transport_iscsi.c @@ -36,6 +36,12 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_session); EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_tcp); EXPORT_TRACEPOINT_SYMBOL_GPL(iscsi_dbg_sw_tcp); +static bool kern_conn_failure; +module_param(kern_conn_failure, bool, S_IRUGO|S_IWUSR); +MODULE_PARM_DESC(kern_conn_failure, + "Allow the kernel to detect and disable broken connections " + "without requiring userspace intervention"); + static int dbg_session; module_param_named(debug_session, dbg_session, int, S_IRUGO | S_IWUSR); @@ -84,6 +90,12 @@ struct iscsi_internal { struct transport_container session_cont; }; +/* Worker to perform connection failure on unresponsive connections + * completely in kernel space. + */ +static void stop_conn_work_fn(struct work_struct *work); +static DECLARE_WORK(stop_conn_work, stop_conn_work_fn); + static atomic_t iscsi_session_nr; /* sysfs session id for next new session */ static struct workqueue_struct *iscsi_eh_timer_workq; @@ -1609,6 +1621,7 @@ static DEFINE_MUTEX(rx_queue_mutex); static LIST_HEAD(sesslist); static DEFINE_SPINLOCK(sesslock); static LIST_HEAD(connlist); +static LIST_HEAD(connlist_err); static DEFINE_SPINLOCK(connlock); static uint32_t iscsi_conn_get_sid(struct iscsi_cls_conn *conn) @@ -2245,6 +2258,7 @@ iscsi_create_conn(struct iscsi_cls_session *session, int dd_size, uint32_t cid) mutex_init(&conn->ep_mutex); INIT_LIST_HEAD(&conn->conn_list); + INIT_LIST_HEAD(&conn->conn_list_err); conn->transport = transport; conn->cid = cid; @@ -2291,6 +2305,7 @@ int iscsi_destroy_conn(struct iscsi_cls_conn *conn) spin_lock_irqsave(&connlock, flags); list_del(&conn->conn_list); + list_del(&conn->conn_list_err); spin_unlock_irqrestore(&connlock, flags); transport_unregister_device(&conn->dev); @@ -2405,6 +2420,28 @@ int iscsi_offload_mesg(struct Scsi_Host *shost, } EXPORT_SYMBOL_GPL(iscsi_offload_mesg); +static void stop_conn_work_fn(struct work_struct *work) +{ + struct iscsi_cls_conn *conn, *tmp; + unsigned long flags; + LIST_HEAD(recovery_list); + + spin_lock_irqsave(&connlock, flags); + if (list_empty(&connlist_err)) { + spin_unlock_irqrestore(&connlock, flags); + return; + } + list_splice_init(&connlist_err, &recovery_list); + spin_unlock_irqrestore(&connlock, flags); + + mutex_lock(&rx_queue_mutex); + list_for_each_entry_safe(conn, tmp, &recovery_list, conn_list_err) { + conn->transport->stop_conn(conn, STOP_CONN_RECOVER); + list_del_init(&conn->conn_list_err); + } + mutex_unlock(&rx_queue_mutex); +} + void iscsi_conn_error_event(struct iscsi_cls_conn *conn, enum iscsi_err error) { struct nlmsghdr *nlh; @@ -2412,6 +2449,15 @@ void iscsi_conn_error_event(struct iscsi_cls_conn *conn, enum iscsi_err error) struct iscsi_uevent *ev; struct iscsi_internal *priv; int len = nlmsg_total_size(sizeof(*ev)); + unsigned long flags; + + if (kern_conn_failure) { + spin_lock_irqsave(&connlock, flags); + list_add(&conn->conn_list_err, &connlist_err); + spin_unlock_irqrestore(&connlock, flags); + + queue_work(system_unbound_wq, &stop_conn_work); + } priv = iscsi_if_transport_lookup(conn->transport); if (!priv) diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h index 325ae731d9ad..2129dc9e2dec 100644 --- a/include/scsi/scsi_transport_iscsi.h +++ b/include/scsi/scsi_transport_iscsi.h @@ -190,6 +190,7 @@ extern void iscsi_ping_comp_event(uint32_t host_no, struct iscsi_cls_conn { struct list_head conn_list; /* item in connlist */ + struct list_head conn_list_err; /* item in connlist_err */ void *dd_data; /* LLD private data */ struct iscsi_transport *transport; uint32_t cid; /* connection id */ -- 2.24.0 -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. 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