Hi,
(03/23/10 11:44), Benjamin Marzinski wrote:
> This patch adds two new configuration parameters to multipath.conf,
> fast_io_fail_tmo and dev_loss_tmo which set
>
> /sys/class/fc_remote_ports/rport-<host>:<channel>-<rport_id>/fast_io_fail_tmo and
> /sys/class/fc_remote_ports/rport-<host>:<channel>-<rport_id>/dev_loss_tmo
...
This is nice feature but the code uses scsi_id instead of rport_id:
> +sysfs_set_scsi_tmo (struct multipath *mpp)
...
> + vector_foreach_slot(mpp->paths, pp, i) {
> + if (safe_snprintf(attr_path, SYSFS_PATH_SIZE,
> + "/class/fc_remote_ports/rport-%d:%d-%d",
> + pp->sg_id.host_no, pp->sg_id.channel,
> + pp->sg_id.scsi_id)) {
> + condlog(0, "attr_path '/class/fc_remote_ports/rport-%d:%d-%d' too large", pp->sg_id.host_no, pp->sg_id.channel, pp->sg_id.scsi_id);
> + return 1;
> + }
So it sets fast_io_fail_tmo/dev_loss_tmo for wrong rport.
For example, I have a storage with node_id 0x2000003013842bcb
connected via switch, whose node_id is 0x100000051e09ee30.
When I set 'fast_io_fail_tmo = 8' in multipath.conf,
multipath command sets the timeout like this:
# for f in /sys/class/fc_remote_ports/rport-*/fast_io_fail_tmo; do d=$(dirname $f); echo $(basename $d):$(cat $d/node_name):$(cat $f); done
rport-0:0-0:0x100000051e09ee30:8
rport-0:0-1:0x100000051e09ee30:8
rport-0:0-2:0x2000003013842bcb:off
rport-0:0-3:0x2000003013842bcb:off
rport-1:0-0:0x100000051e09ee30:8
rport-1:0-1:0x100000051e09ee30:8
rport-1:0-2:0x2000003013842bcb:off
rport-1:0-3:0x2000003013842bcb:off
As a result, when a link is down for the storage and fast_io_fail_tmo
has passed, I/O will be still blocked.
Attached is a quick patch for this problem.
With this patch, fast_io_fail_tmo is set like this:
rport-0:0-0:0x100000051e09ee30:8
rport-0:0-1:0x100000051e09ee30:8
rport-0:0-2:0x2000003013842bcb:off
rport-0:0-3:0x2000003013842bcb:off
rport-1:0-0:0x100000051e09ee30:8
rport-1:0-1:0x100000051e09ee30:8
rport-1:0-2:0x2000003013842bcb:off
rport-1:0-3:0x2000003013842bcb:off
Others might have better idea about resolving rport_id from target.
Mike, Hannes, any comments?
Thanks,
--
Jun'ichi Nomura, NEC Corporation
rport_id != scsi_id
multipath should find rport_id from the target_id.
diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 122eb8f..c371b47 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -10,6 +10,7 @@
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
+#include <libgen.h>
#include "checkers.h"
#include "vector.h"
@@ -204,6 +205,41 @@ sysfs_get_fc_nodename (struct sysfs_device * dev, char * node,
return 1;
}
+static int
+find_rport_id(struct path *pp)
+{
+ char attr_path[SYSFS_PATH_SIZE];
+ char *dir, *base;
+ int host, channel, rport_id = -1;
+
+ if (safe_sprintf(attr_path,
+ "/class/fc_transport/target%i:%i:%i",
+ pp->sg_id.host_no, pp->sg_id.channel,
+ pp->sg_id.scsi_id)) {
+ condlog(0, "attr_path too small for target");
+ return 1;
+ }
+
+ if (sysfs_resolve_link(attr_path, SYSFS_PATH_SIZE))
+ return -1;
+
+ condlog(4, "target%d:%d:%d -> path %s", pp->sg_id.host_no, pp->sg_id.channel, pp->sg_id.scsi_id, attr_path);
+ dir = attr_path;
+ do {
+ base = basename(dir);
+ dir = dirname(dir);
+
+ if (sscanf((const char *)base, "rport-%d:%d-%d", &host, &channel, &rport_id) == 3)
+ break;
+ } while (strcmp((const char *)dir, "/"));
+
+ if (rport_id < 0)
+ return -1;
+
+ condlog(4, "target%d:%d:%d -> rport_id %d", pp->sg_id.host_no, pp->sg_id.channel, pp->sg_id.scsi_id, rport_id);
+ return rport_id;
+}
+
int
sysfs_set_scsi_tmo (struct multipath *mpp)
{
@@ -211,15 +247,22 @@ sysfs_set_scsi_tmo (struct multipath *mpp)
struct path *pp;
int i;
char value[11];
+ int rport_id;
if (!mpp->dev_loss && !mpp->fast_io_fail)
return 0;
vector_foreach_slot(mpp->paths, pp, i) {
+ rport_id = find_rport_id(pp);
+ if (rport_id < 0) {
+ condlog(0, "failed to find rport_id for target%d:%d:%d", pp->sg_id.host_no, pp->sg_id.channel, pp->sg_id.scsi_id);
+ return 1;
+ }
+
if (safe_snprintf(attr_path, SYSFS_PATH_SIZE,
"/class/fc_remote_ports/rport-%d:%d-%d",
pp->sg_id.host_no, pp->sg_id.channel,
- pp->sg_id.scsi_id)) {
- condlog(0, "attr_path '/class/fc_remote_ports/rport-%d:%d-%d' too large", pp->sg_id.host_no, pp->sg_id.channel, pp->sg_id.scsi_id);
+ rport_id)) {
+ condlog(0, "attr_path '/class/fc_remote_ports/rport-%d:%d-%d' too large", pp->sg_id.host_no, pp->sg_id.channel, rport_id);
return 1;
}
if (mpp->dev_loss){
--
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