Hi,
Below is the patch for the implementation of preferred path feature in the device mapper.
Preferred path feature allows the selection of a particular path for a LUN, by making proper priority assignments.
mpath_prio_pp is a callout routine for the same.Let me know your comments.
Thanks,
Veena
diff -pNaur multipath-tools-0.4.8/libmultipath/config.h multipath-tools-0.4.8.new/libmultipath/config.h
--- multipath-tools-0.4.8/libmultipath/config.h 2007-08-03 02:35:37.000000000 +0530
+++ multipath-tools-0.4.8.new/libmultipath/config.h 2007-11-30 12:40:33.000000000 +0530
@@ -37,6 +37,7 @@ struct mpentry {
char * alias;
char * getuid;
char * selector;
+ char * getprio;
int pgpolicy;
int pgfailback;
diff -pNaur multipath-tools-0.4.8/libmultipath/dict.c multipath-tools-0.4.8.new/libmultipath/dict.c
--- multipath-tools-0.4.8/libmultipath/dict.c 2007-08-03 02:35:37.000000000 +0530
+++ multipath-tools-0.4.8.new/libmultipath/dict.c 2007-11-30 12:13:46.000000000 +0530
@@ -933,9 +933,31 @@ mp_pg_timeout_handler(vector strvec)
return 0;
}
+static int
+mp_prio_callout_handler(vector strvec)
+{
+ struct mpentry * mpe = VECTOR_LAST_SLOT(conf->mptable);
+
+ if(!mpe)
+ return 1;
+
+ mpe->getprio = set_value(strvec);
+
+ if(!mpe->getprio)
+ return 1;
+
+ if (strlen(mpe->getprio) == 4 && !strcmp(mpe->getprio, "none")) {
+ FREE(mpe->getprio);
+ mpe->getprio = NULL;
+ }
+
+ return 0;
+}
+
/*
* config file keywords printing
*/
+
static int
snprint_mp_wwid (char * buff, int len, void * data)
{
@@ -1068,6 +1090,17 @@ snprint_mp_pg_timeout (char * buff, int
}
static int
+snprint_mp_prio_callout(char * buff, int len, void * data)
+{
+ struct mpentry * mpe = (struct mpentry *)data;
+
+ if (!mpe->getprio)
+ return 0;
+
+ return snprintf(buff, len, "%s", mpe->getprio);
+}
+
+static int
snprint_hw_vendor (char * buff, int len, void * data)
{
struct hwentry * hwe = (struct hwentry *)data;
@@ -1594,6 +1627,7 @@ init_keywords(void)
install_keyword("alias", &alias_handler, &snprint_mp_alias);
install_keyword("path_grouping_policy", &mp_pgpolicy_handler, &snprint_mp_path_grouping_policy);
install_keyword("path_selector", &mp_selector_handler, &snprint_mp_selector);
+ install_keyword("prio_callout", &mp_prio_callout_handler, &snprint_mp_prio_callout);
install_keyword("failback", &mp_failback_handler, &snprint_mp_failback);
install_keyword("rr_weight", &mp_weight_handler, &snprint_mp_rr_weight);
install_keyword("no_path_retry", &mp_no_path_retry_handler, &snprint_mp_no_path_retry);
diff -pNaur multipath-tools-0.4.8/libmultipath/discovery.c multipath-tools-0.4.8.new/libmultipath/discovery.c
--- multipath-tools-0.4.8/libmultipath/discovery.c 2007-08-03 02:35:37.000000000 +0530
+++ multipath-tools-0.4.8.new/libmultipath/discovery.c 2007-11-30 12:18:21.000000000 +0530
@@ -709,8 +709,11 @@ pathinfo (struct path *pp, vector hwtabl
* been successfully obtained before.
*/
if (mask & DI_PRIO &&
- (pp->state != PATH_DOWN || pp->priority == PRIO_UNDEF))
+ (pp->state != PATH_DOWN || pp->priority == PRIO_UNDEF)) {
+ if( !strlen(pp->wwid))
+ get_uid(pp);
get_prio(pp);
+ }
if (mask & DI_WWID && !strlen(pp->wwid))
get_uid(pp);
diff -pNaur multipath-tools-0.4.8/libmultipath/propsel.c multipath-tools-0.4.8.new/libmultipath/propsel.c
--- multipath-tools-0.4.8/libmultipath/propsel.c 2007-08-03 02:35:37.000000000 +0530
+++ multipath-tools-0.4.8.new/libmultipath/propsel.c 2007-11-30 12:45:21.000000000 +0530
@@ -258,7 +258,16 @@ select_getuid (struct path * pp)
extern int
select_getprio (struct path * pp)
-{
+{
+ struct mpentry * mpe;
+ if (mpe = find_mpe(pp->wwid)) {
+ if (mpe->getprio) {
+ pp->getprio = mpe->getprio;
+ condlog(3, "%s: getprio = %s (LUN setting)", pp->dev, pp->getprio);
+ return 0;
+ }
+ }
+
if (pp->hwe && pp->hwe->getprio) {
pp->getprio = pp->hwe->getprio;
condlog(3, "%s: getprio = %s (controller setting)",
diff -pNaur multipath-tools-0.4.8/path_priority/pp_pref_path/Makefile multipath-tools-0.4.8.new/path_priority/pp_pref_path/Makefile
--- multipath-tools-0.4.8/path_priority/pp_pref_path/Makefile 1970-01-01 05:30:00.000000000 +0530
+++ multipath-tools-0.4.8.new/path_priority/pp_pref_path/Makefile 2007-11-30 11:47:21.000000000 +0530
@@ -0,0 +1,25 @@
+EXEC = mpath_prio_pp
+BUILD = glibc
+OBJS = mpath_prio_pp.o
+
+TOPDIR = ../..
+include $(TOPDIR)/Makefile.inc
+
+all: $(BUILD)
+
+glibc: $(OBJS)
+ $(CC) -o $(EXEC) $(OBJS) $(LDFLAGS)
+
+klibc: $(OBJS)
+ $(CC) -static -o $(EXEC) $(OBJS)
+
+install: $(EXEC)
+ install -m 755 $(EXEC) $(DESTDIR)$(bindir)/$(EXEC)
+
+uninstall:
+ rm $(DESTDIR)$(bindir)/$(EXEC)
+clean:
+ rm -f *.o $(EXEC)
+
+%.o: %.c
+ $(CC) $(CFLAGS) -c -o $@ $<
diff -pNaur multipath-tools-0.4.8/path_priority/pp_pref_path/mpath_prio_pp.c multipath-tools-0.4.8.new/path_priority/pp_pref_path/mpath_prio_pp.c
--- multipath-tools-0.4.8/path_priority/pp_pref_path/mpath_prio_pp.c 1970-01-01 05:30:00.000000000 +0530
+++ multipath-tools-0.4.8.new/path_priority/pp_pref_path/mpath_prio_pp.c 2007-12-04 16:54:21.000000000 +0530
@@ -0,0 +1,67 @@
+ /*
+ *****************************************************************************
+ * *
+ * (C) Copyright 2007 Hewlett-Packard Development Company, L.P *
+ * *
+ * This program is free software; you can redistribute it and/or modify it *
+ * under the terms of the GNU General Public License as published by the Free*
+ * Software Foundation; either version 2 of the License, or (at your option)*
+ * any later version. *
+ * *
+ * This program is distributed in the hope that it will be useful, but *
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY*
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
+ * for more details. *
+ * *
+ * You should have received a copy of the GNU General Public License along *
+ * with this program; if not, write to the Free Software Foundation, Inc., *
+ * 675 Mass Ave, Cambridge, MA 02139, USA. *
+ * *
+ * The copy of the GNU General Public License is available at *
+ * /opt/hp/HPDMmultipath-tool directoy *
+ * *
+ *****************************************************************************
+ */
+
+/*
+ * Prioritizer for device mapper,when a path instance is provided as the
+ * preferred path.
+
+ * This prioritizer assigns a priority value based on the comparison made
+ * between the preferred path and the path instance for which this is called.
+ * A priority value of 1 is assigned to the preferred path and 0 to the other
+ * non-preferred paths.
+
+ * Returns zero on successful assignment of priority and -1 on failure.
+ * Failure to assign priority can be caused due to invalid pathname or a missing * argument.
+ */
+
+#include<stdio.h>
+#include<string.h>
+#define HIGH 1
+#define LOW 0
+#define FILE_NAME_SIZE 256
+
+int main(int argc, char * argv[])
+{
+
+ char path[FILE_NAME_SIZE];
+
+ if(argv[1] && argv[2])
+ {
+ if(!strncmp(argv[2],"/dev/",5))
+ strcpy(path,argv[2]+5);
+
+ if(!strcmp(path,argv[1]) || !strcmp(argv[1],argv[2]))
+ {
+ printf("%u\n", HIGH);
+ return 0;
+ }
+ else
+ {
+ printf("%u\n", LOW);
+ return 0;
+ }
+ }
+ return -1;
+}
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