[PATCH 0/3] Changes to Userspace multipath code to support lsi-rdac

[PATCH 0/3] Changes to Userspace multipath code to support lsi-rdac

[Chandra Seetharaman]

Hi All,

While working on lsi-rdac hardware handler, I found that the checkers "tur"
and "readsector0" are not serving the lsi-rdac properly. Also, the storage
device has a active/passive state which need to be handled properly.

So, I wrote a new path checker for lsi-rdac, to use the C4 inquiry page to get
the current owner of the lun and set the state as UP(active) or GHOST(passive).
Changes are in patch 1/3.

After applying the above patch, I realized the priorities are not set properly.
Made some changes to use the GHOST state while setting priorities. Changes are
in patch 2/3.

Debugging the above patches found that the wait time (5 seconds) in multipathd
was not sufficient for the devices to appear in /dev/ It was taking about 20
seconds. Changed the wait time to be 60 seconds. Change in patch 3/3.

Please provide me with your feedback/comment on these changes regarding
correctness, completeness etc.,

Thanks & regards,

chandra

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

[PATCH 1/3] C4 Inquiry based path checker

[Chandra Seetharaman]

Index: multipath-tools-0.4.7/libcheckers/Makefile
===================================================================
--- multipath-tools-0.4.7.orig/libcheckers/Makefile	2007-03-02 18:42:00.000000000 -0800
+++ multipath-tools-0.4.7/libcheckers/Makefile	2007-03-02 18:42:19.000000000 -0800
@@ -6,7 +6,7 @@
 
 include ../Makefile.inc
 
-OBJS = checkers.o readsector0.o tur.o directio.o emc_clariion.o hp_sw.o
+OBJS = checkers.o readsector0.o tur.o directio.o emc_clariion.o hp_sw.o rdac.o
 
 all: $(BUILD)
 
Index: multipath-tools-0.4.7/libcheckers/rdac.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ multipath-tools-0.4.7/libcheckers/rdac.c	2007-03-20 14:43:38.000000000 -0700
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2005 Christophe Varoqui
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <errno.h>
+
+#include "checkers.h"
+
+#include "../libmultipath/sg_include.h"
+
+#define INQUIRY_CMDLEN		6
+#define INQUIRY_CMD		0x12
+#define SENSE_BUFF_LEN		32
+#define DEF_TIMEOUT		60000
+#define SCSI_CHECK_CONDITION	0x2
+#define SCSI_COMMAND_TERMINATED	0x22
+#define SG_ERR_DRIVER_SENSE	0x08
+#define RECOVERED_ERROR		0x01
+
+#define MSG_RDAC_UP	"rdac checker reports path is up"
+#define MSG_RDAC_DOWN	"rdac checker reports path is down"
+#define MSG_RDAC_GHOST	"rdac checker reports path is ghost"
+
+struct rdac_checker_context {
+	void * dummy;
+};
+
+int rdac_init (struct checker * c)
+{
+	return 0;
+}
+
+void rdac_free (struct checker * c)
+{
+	return;
+}
+
+static int
+do_inq(int sg_fd, unsigned int pg_op, void *resp, int mx_resp_len)
+{
+	unsigned char inqCmdBlk[INQUIRY_CMDLEN] = { INQUIRY_CMD, 1, 0, 0, 0, 0 };
+	unsigned char sense_b[SENSE_BUFF_LEN];
+	struct sg_io_hdr io_hdr;
+
+	inqCmdBlk[2] = (unsigned char) pg_op;
+	inqCmdBlk[4] = (unsigned char) (mx_resp_len & 0xff);
+	memset(&io_hdr, 0, sizeof (struct sg_io_hdr));
+
+	io_hdr.interface_id = 'S';
+	io_hdr.cmd_len = sizeof (inqCmdBlk);
+	io_hdr.mx_sb_len = sizeof (sense_b);
+	io_hdr.dxfer_direction = SG_DXFER_FROM_DEV;
+	io_hdr.dxfer_len = mx_resp_len;
+	io_hdr.dxferp = resp;
+	io_hdr.cmdp = inqCmdBlk;
+	io_hdr.sbp = sense_b;
+	io_hdr.timeout = DEF_TIMEOUT;
+
+	if (ioctl(sg_fd, SG_IO, &io_hdr) < 0)
+		return 1;
+
+	/* treat SG_ERR here to get rid of sg_err.[ch] */
+	io_hdr.status &= 0x7e;
+	if ((0 == io_hdr.status) && (0 == io_hdr.host_status) &&
+			(0 == io_hdr.driver_status))
+		return 0;
+	if ((SCSI_CHECK_CONDITION == io_hdr.status) ||
+		(SCSI_COMMAND_TERMINATED == io_hdr.status) ||
+		(SG_ERR_DRIVER_SENSE == (0xf & io_hdr.driver_status))) {
+		if (io_hdr.sbp && (io_hdr.sb_len_wr > 2)) {
+			int sense_key;
+			unsigned char * sense_buffer = io_hdr.sbp;
+			if (sense_buffer[0] & 0x2)
+				sense_key = sense_buffer[1] & 0xf;
+			else
+				sense_key = sense_buffer[2] & 0xf;
+			if (RECOVERED_ERROR == sense_key)
+				return 0;
+		}
+	}
+	return 1;
+}
+
+struct volume_access_inq
+{
+	char dontcare0[8];
+	char avtcvp;
+	char dontcare1[39];
+};
+
+extern int
+rdac(struct checker * c)
+{
+	struct volume_access_inq inq;
+
+	if (0 != do_inq(c->fd, 0xC9, &inq, sizeof(struct volume_access_inq))) {
+		MSG(c, MSG_RDAC_DOWN);
+		return PATH_DOWN;
+	}
+
+	return ((inq.avtcvp & 0x1) ? PATH_UP : PATH_GHOST);
+}
Index: multipath-tools-0.4.7/libcheckers/checkers.c
===================================================================
--- multipath-tools-0.4.7.orig/libcheckers/checkers.c	2006-03-13 03:07:45.000000000 -0800
+++ multipath-tools-0.4.7/libcheckers/checkers.c	2007-03-20 14:44:56.000000000 -0700
@@ -7,6 +7,7 @@
 #include "tur.h"
 #include "hp_sw.h"
 #include "emc_clariion.h"
+#include "rdac.h"
 #include "readsector0.h"
 
 static struct checker checkers[] = {
@@ -48,6 +49,15 @@
 	},
 	{
 		.fd         = 0,
+		.name       = RDAC,
+		.message    = "",
+		.context    = NULL,
+		.check      = rdac,
+		.init       = rdac_init,
+		.free       = rdac_free
+	},
+	{
+		.fd         = 0,
 		.name       = READSECTOR0,
 		.message    = "",
 		.context    = NULL,
Index: multipath-tools-0.4.7/libcheckers/rdac.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ multipath-tools-0.4.7/libcheckers/rdac.h	2007-03-20 14:43:58.000000000 -0700
@@ -0,0 +1,8 @@
+#ifndef _RDAC_H
+#define _RDAC_H
+
+int rdac(struct checker *);
+int rdac_init(struct checker *);
+void rdac_free(struct checker *);
+
+#endif /* _RDAC_H */
Index: multipath-tools-0.4.7/libcheckers/checkers.h
===================================================================
--- multipath-tools-0.4.7.orig/libcheckers/checkers.h	2006-03-13 03:07:45.000000000 -0800
+++ multipath-tools-0.4.7/libcheckers/checkers.h	2007-03-02 18:50:48.000000000 -0800
@@ -14,6 +14,7 @@
 #define DIRECTIO     "directio"
 #define TUR          "tur"
 #define HP_SW        "hp_sw"
+#define RDAC         "rdac"
 #define EMC_CLARIION "emc_clariion"
 #define READSECTOR0  "readsector0"
 

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

[PATCH 2/3] Fix the priority calculation to use PATH_GHOST state

[Chandra Seetharaman]

Index: multipath-tools-0.4.7/libmultipath/discovery.c
===================================================================
--- multipath-tools-0.4.7.orig/libmultipath/discovery.c	2007-03-20 14:45:21.000000000 -0700
+++ multipath-tools-0.4.7/libmultipath/discovery.c	2007-03-20 14:45:41.000000000 -0700
@@ -699,7 +699,7 @@
 	if (mask & DI_CHECKER && get_state(pp))
 		goto blank;
 	
-	if (mask & DI_PRIO && pp->state != PATH_DOWN)
+	if (mask & DI_PRIO && pp->state == PATH_UP)
 		get_prio(pp);
 
 	if (mask & DI_WWID && !strlen(pp->wwid))
Index: multipath-tools-0.4.7/libmultipath/switchgroup.c
===================================================================
--- multipath-tools-0.4.7.orig/libmultipath/switchgroup.c	2007-03-20 14:45:21.000000000 -0700
+++ multipath-tools-0.4.7/libmultipath/switchgroup.c	2007-03-20 14:45:41.000000000 -0700
@@ -28,7 +28,7 @@
 		priority = 0;
 
 		vector_foreach_slot (pgp->paths, pp, j) {
-			if (pp->state != PATH_DOWN)
+			if (pp->state == PATH_UP)
 				priority += pp->priority;
 		}
 		pgp->priority = priority;

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

[PATCH 3/3] Increase the wait time for device to appear in /dev

[Chandra Seetharaman]

Index: multipath-tools-0.4.7/libmultipath/discovery.c
===================================================================
--- multipath-tools-0.4.7.orig/libmultipath/discovery.c	2007-03-20 14:45:41.000000000 -0700
+++ multipath-tools-0.4.7/libmultipath/discovery.c	2007-03-20 14:46:16.000000000 -0700
@@ -112,7 +112,7 @@
  * not multipath(8), ran by udev
  */
 #if DAEMON
-#define WAIT_MAX_SECONDS 5
+#define WAIT_MAX_SECONDS 60
 #define WAIT_LOOP_PER_SECOND 5
 
 static int

-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------

Re: [PATCH 0/3] Changes to Userspace multipath code to support lsi-rdac

[Christophe Varoqui]

Le mercredi 21 mars 2007 à 11:38 -0800, Chandra Seetharaman a écrit :
> Hi All,
> 
> While working on lsi-rdac hardware handler, I found that the checkers "tur"
> and "readsector0" are not serving the lsi-rdac properly. Also, the storage
> device has a active/passive state which need to be handled properly.
> 
> So, I wrote a new path checker for lsi-rdac, to use the C4 inquiry page to get
> the current owner of the lun and set the state as UP(active) or GHOST(passive).
> Changes are in patch 1/3.
> 
> After applying the above patch, I realized the priorities are not set properly.
> Made some changes to use the GHOST state while setting priorities. Changes are
> in patch 2/3.
> 
> Debugging the above patches found that the wait time (5 seconds) in multipathd
> was not sufficient for the devices to appear in /dev/ It was taking about 20
> seconds. Changed the wait time to be 60 seconds. Change in patch 3/3.
> 
> Please provide me with your feedback/comment on these changes regarding
> correctness, completeness etc.,
> 
Looks very good. I merged the 3 patches.

In 1/3, I changed the DEF_TIMEOUT name to avoid surcharging the one in
checker.h

I'm having a hard time push to kernel.org, so don't expect to see the
git tree updated soon.

Thanks,
cvaroqui

Re: Re: [PATCH 0/3] Changes to Userspace multipath code to support lsi-rdac

[Bernd Zeimetz]

Hi,
> I'm having a hard time push to kernel.org, so don't expect to see the
> git tree updated soon.
>   
hmm. git.kernel.org seems to work well, at least to get stuff - I have
nothing to push.

Is there any other place where one could grab the latest
multipath-tools, and probably recent kernel modules to test?

Thanks,

-- 
Bernd Zeimetz
<bernd@bzed.de>                         <http://bzed.de/>

Re: [PATCH 0/3] Changes to Userspace multipath code to support lsi-rdac

[Chandra Seetharaman]

Cool,

Thanks.

chandra
On Thu, 2007-03-22 at 00:06 +0100, Christophe Varoqui wrote:
> Le mercredi 21 mars 2007 à 11:38 -0800, Chandra Seetharaman a écrit :
> > Hi All,
> > 
> > While working on lsi-rdac hardware handler, I found that the checkers "tur"
> > and "readsector0" are not serving the lsi-rdac properly. Also, the storage
> > device has a active/passive state which need to be handled properly.
> > 
> > So, I wrote a new path checker for lsi-rdac, to use the C4 inquiry page to get
> > the current owner of the lun and set the state as UP(active) or GHOST(passive).
> > Changes are in patch 1/3.
> > 
> > After applying the above patch, I realized the priorities are not set properly.
> > Made some changes to use the GHOST state while setting priorities. Changes are
> > in patch 2/3.
> > 
> > Debugging the above patches found that the wait time (5 seconds) in multipathd
> > was not sufficient for the devices to appear in /dev/ It was taking about 20
> > seconds. Changed the wait time to be 60 seconds. Change in patch 3/3.
> > 
> > Please provide me with your feedback/comment on these changes regarding
> > correctness, completeness etc.,
> > 
> Looks very good. I merged the 3 patches.
> 
> In 1/3, I changed the DEF_TIMEOUT name to avoid surcharging the one in
> checker.h
> 
> I'm having a hard time push to kernel.org, so don't expect to see the
> git tree updated soon.
> 
> Thanks,
> cvaroqui
> 
-- 

----------------------------------------------------------------------
    Chandra Seetharaman               | Be careful what you choose....
              - sekharan@us.ibm.com   |      .......you may get it.
----------------------------------------------------------------------