iscsi sysfs: check state before onlining devschk-state

In 5.6, the commit:

commit 0ab710458da113a71c461c4df27e7f1353d9f864
Author: Bharath Ravi <rbharath@google.com>
Date:   Sat Jan 25 01:19:25 2020 -0500

    scsi: iscsi: Perform connection failure entirely in kernel space

made it so the kernel can start the recovery process. This means that
after the start conn operation the kernel could set the device into the
block stated. We can then hit a race where iscsid has done start conn,
and is calling session_online_devs but the kernel has hit an issue and is
now setting the device's to blocked.

This adds a check for if the device is in the offline state before trying
to set the state to running.

1 files changed, 24 insertions, 1 deletions

diff --git a/usr/iscsi_sysfs.c b/usr/iscsi_sysfs.c
index abefde2..7bb834a 100644
--- a/usr/iscsi_sysfs.c
+++ b/usr/iscsi_sysfs.c
@@ -1929,18 +1929,41 @@ void iscsi_sysfs_set_queue_depth(void *data, int hostno, int target, int lun)
 void iscsi_sysfs_set_device_online(__attribute__((unused))void *data,
 				   int hostno, int target, int lun)
 {
-	char *write_buf = "running\n";
+	char *write_buf = "running\n", *state;
 	char id[NAME_SIZE];
 	int err;
 
 	snprintf(id, sizeof(id), "%d:0:%d:%d", hostno, target, lun);
 	log_debug(4, "online device %s", id);
 
+	state = sysfs_get_value(id, SCSI_SUBSYS, "state");
+	if (!state) {
+		log_error("Could not read state for LUN %s\n", id);
+		goto set_state;
+	}
+
+	if (!strcmp(state, "running"))
+		goto done;
+	/*
+	 * The kernel can start to perform session level recovery cleanup
+	 * any time after the conn start call, so we only want to change the
+	 * state if we are in one of the offline states.
+	 */
+	if (strcmp(state, "offline") && strcmp(state, "transport-offline")) {
+		log_debug(4, "Dev not offline. Skip onlining %s", id);
+		goto done;
+	}
+
+set_state:
 	err = sysfs_set_param(id, SCSI_SUBSYS, "state", write_buf,
 			      strlen(write_buf));
 	if (err && err != EINVAL)
 		/* we should read the state */
 		log_error("Could not online LUN %d err %d.", lun, err);
+
+done:
+	if (state)
+		free(state);
 }
 
 void iscsi_sysfs_rescan_device(__attribute__((unused))void *data,