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* Re: [PATCH] multipath: add fast_io_fail and dev_loss_tmo config parameters
@ 2010-07-30  9:13 Jun'ichi Nomura
  2010-08-03  1:18 ` Jun'ichi Nomura
  2010-08-03 18:15 ` Benjamin Marzinski
  0 siblings, 2 replies; 4+ messages in thread
From: Jun'ichi Nomura @ 2010-07-30  9:13 UTC (permalink / raw)
  To: device-mapper development, Benjamin Marzinski
  Cc: Kiyoshi Ueda, Michael Christie

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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

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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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^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH] multipath: add fast_io_fail and dev_loss_tmo config parameters
@ 2010-03-23  2:44 Benjamin Marzinski
  0 siblings, 0 replies; 4+ messages in thread
From: Benjamin Marzinski @ 2010-03-23  2:44 UTC (permalink / raw)
  To: device-mapper development

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

for all the capable paths in a multipath device.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmultipath/config.h      |    4 +
 libmultipath/configure.c   |    3 +
 libmultipath/dict.c        |  102 +++++++++++++++++++++++++++++++++++++++++++++
 libmultipath/discovery.c   |   37 ++++++++++++++++
 libmultipath/discovery.h   |    1 
 libmultipath/propsel.c     |   42 ++++++++++++++++++
 libmultipath/propsel.h     |    2 
 libmultipath/structs.h     |    2 
 libmultipath/sysfs.c       |   56 ++++++++++++++++++++++++
 libmultipath/sysfs.h       |    3 -
 multipath.conf.annotated   |   38 ++++++++++++++++
 multipath/multipath.conf.5 |   15 ++++++
 12 files changed, 303 insertions(+), 2 deletions(-)

Index: multipath-tools-100322/multipath.conf.annotated
===================================================================
--- multipath-tools-100322.orig/multipath.conf.annotated
+++ multipath-tools-100322/multipath.conf.annotated
@@ -191,6 +191,25 @@
 #	# default : determined by the process
 #	gid disk
 #
+#	#
+#	# name    : fast_io_fail_tmo
+#	# scope   : multipath & multipathd
+#	# desc    : The number of seconds the scsi layer will wait after a
+#	#           problem has been detected on a FC remote port before failing
+#	#           IO to devices on that remote port.
+#	# values  : off | n >= 0 (smaller than dev_loss_tmo)
+#	# default : determined by the OS
+#	fast_io_fail_tmo 5
+#
+#	#
+#	# name    : dev_loss_tmo
+#	# scope   : multipath & multipathd
+#	# desc    : The number of seconds the scsi layer will wait after a
+#	#           problem has been detected on a FC remote port before
+#	#           removing it from the system.
+#	# values  : n > 0
+#	# default : determined by the OS
+#	dev_loss_tmo 600
 #}
 #	
 ##
@@ -504,7 +523,6 @@
 #		# desc    : If set to "yes", multipathd will disable queueing
 #		#           when the last path to a device has been deleted.
 #		# values  : yes|no
-#		# default : no
 #		#
 #		flush_on_last_del       yes
 #
@@ -514,6 +532,24 @@
 #		# desc    : product strings to blacklist for this vendor
 #		#
 #		product_blacklist	LUN_Z
+#
+#		#
+#		# name    : fast_io_fail_tmo
+#		# scope   : multipath & multipathd
+#		# desc    : The number of seconds the scsi layer will wait after
+#		#           a problem has been detected on a FC remote port
+#		#           before failing IO to devices on that remote port.
+#		# values  : off | n >= 0 (smaller than dev_loss_tmo)
+#		fast_io_fail_tmo 5
+#
+#		#
+#		# name    : dev_loss_tmo
+#		# scope   : multipath & multipathd
+#		# desc    : The number of seconds the scsi layer will wait after
+#		#           a problem has been detected on a FC remote port
+#		#           before removing it from the system.
+#		# values  : n > 0
+#		dev_loss_tmo 600
 #	}
 #	device {
 #		vendor			"COMPAQ  "
Index: multipath-tools-100322/multipath/multipath.conf.5
===================================================================
--- multipath-tools-100322.orig/multipath/multipath.conf.5
+++ multipath-tools-100322/multipath/multipath.conf.5
@@ -240,6 +240,17 @@ this to the system limit from /proc/sys/
 maximum number of open fds is taken from the calling process. It is usually
 1024. To be safe, this should be set to the maximum number of paths plus 32,
 if that number is greated than 1024.
+.TP
+.B fast_io_fail_tmo
+Specify the number of seconds the scsi layer will wait after a problem has been
+detected on a FC remote port before failing IO to devices on that remote port.
+This should be smaller than dev_loss_tmo. Setting this to
+.I off
+will disable the timeout.
+.TP
+.B dev_loss_tmo
+Specify the number of seconds the scsi layer will wait after a problem has
+been detected on a FC remote port before removing it from the system.
 .
 .SH "blacklist section"
 The
@@ -384,6 +395,10 @@ section:
 .B no_path_retry
 .TP
 .B rr_min_io
+.TP
+.B fast_io_fail_tmo
+.TP
+.B dev_loss_tmo
 .RE
 .PD
 .LP
Index: multipath-tools-100322/libmultipath/dict.c
===================================================================
--- multipath-tools-100322.orig/libmultipath/dict.c
+++ multipath-tools-100322/libmultipath/dict.c
@@ -37,6 +37,35 @@ polling_interval_handler(vector strvec)
 }
 
 static int
+def_fast_io_fail_handler(vector strvec)
+{
+	char * buff;
+
+	buff = set_value(strvec);
+	if (strlen(buff) == 3 && !strcmp(buff, "off"))
+		conf->fast_io_fail = -1;
+	else if (sscanf(buff, "%d", &conf->fast_io_fail) != 1 ||
+		 conf->fast_io_fail < -1)
+		conf->fast_io_fail = 0;
+
+	FREE(buff);
+	return 0;
+}
+
+static int
+def_dev_loss_handler(vector strvec)
+{
+	char * buff;
+
+	buff = set_value(strvec);
+	if (sscanf(buff, "%u", &conf->dev_loss) != 1)
+		conf->dev_loss = 0;
+
+	FREE(buff);
+	return 0;
+}
+
+static int
 verbosity_handler(vector strvec)
 {
 	char * buff;
@@ -628,6 +657,37 @@ bl_product_handler(vector strvec)
 }
 
 static int
+hw_fast_io_fail_handler(vector strvec)
+{
+	char * buff;
+	struct hwentry * hwe = VECTOR_LAST_SLOT(conf->hwtable);
+
+	buff = set_value(strvec);
+	if (strlen(buff) == 3 && !strcmp(buff, "off"))
+		hwe->fast_io_fail = -1;
+	else if (sscanf(buff, "%d", &hwe->fast_io_fail) != 1 ||
+		 hwe->fast_io_fail < -1)
+		hwe->fast_io_fail = 0;
+
+	FREE(buff);
+	return 0;
+}
+
+static int
+hw_dev_loss_handler(vector strvec)
+{
+	char * buff;
+	struct hwentry * hwe = VECTOR_LAST_SLOT(conf->hwtable);
+
+	buff = set_value(strvec);
+	if (sscanf(buff, "%u", &hwe->dev_loss) != 1)
+		hwe->dev_loss = 0;
+
+	FREE(buff);
+	return 0;
+}
+
+static int
 hw_pgpolicy_handler(vector strvec)
 {
 	char * buff;
@@ -1390,6 +1450,26 @@ snprint_mp_flush_on_last_del (char * buf
 }
 
 static int
+snprint_hw_fast_io_fail(char * buff, int len, void * data)
+{
+	struct hwentry * hwe = (struct hwentry *)data;
+	if (!hwe->fast_io_fail)
+		return 0;
+	if (hwe->fast_io_fail == -1)
+		return snprintf(buff, len, "off");
+	return snprintf(buff, len, "%d", hwe->fast_io_fail);
+}
+
+static int
+snprint_hw_dev_loss(char * buff, int len, void * data)
+{
+	struct hwentry * hwe = (struct hwentry *)data;
+	if (!hwe->dev_loss)
+		return 0;
+	return snprintf(buff, len, "%u", hwe->dev_loss);
+}
+
+static int
 snprint_hw_vendor (char * buff, int len, void * data)
 {
 	struct hwentry * hwe = (struct hwentry *)data;
@@ -1640,6 +1720,24 @@ snprint_def_polling_interval (char * buf
 }
 
 static int
+snprint_def_fast_io_fail(char * buff, int len, void * data)
+{
+	if (!conf->fast_io_fail)
+		return 0;
+	if (conf->fast_io_fail == -1)
+		return snprintf(buff, len, "off");
+	return snprintf(buff, len, "%d", conf->fast_io_fail);
+}
+
+static int
+snprint_def_dev_loss(char * buff, int len, void * data)
+{
+	if (!conf->dev_loss)
+		return 0;
+	return snprintf(buff, len, "%u", conf->dev_loss);
+}
+
+static int
 snprint_def_verbosity (char * buff, int len, void * data)
 {
 	if (conf->checkint == DEFAULT_VERBOSITY)
@@ -1937,6 +2035,8 @@ init_keywords(void)
 	install_keyword("mode", &def_mode_handler, &snprint_def_mode);
 	install_keyword("uid", &def_uid_handler, &snprint_def_uid);
 	install_keyword("gid", &def_gid_handler, &snprint_def_gid);
+	install_keyword("fast_io_fail_tmo", &def_fast_io_fail_handler, &snprint_def_fast_io_fail);
+	install_keyword("dev_loss_tmo", &def_dev_loss_handler, &snprint_def_dev_loss);
 	__deprecated install_keyword("default_selector", &def_selector_handler, NULL);
 	__deprecated install_keyword("default_path_grouping_policy", &def_pgpolicy_handler, NULL);
 	__deprecated install_keyword("default_getuid_callout", &def_getuid_callout_handler, NULL);
@@ -1991,6 +2091,8 @@ init_keywords(void)
 	install_keyword("rr_min_io", &hw_minio_handler, &snprint_hw_rr_min_io);
 	install_keyword("pg_timeout", &hw_pg_timeout_handler, &snprint_hw_pg_timeout);
 	install_keyword("flush_on_last_del", &hw_flush_on_last_del_handler, &snprint_hw_flush_on_last_del);
+	install_keyword("fast_io_fail_tmo", &hw_fast_io_fail_handler, &snprint_hw_fast_io_fail);
+	install_keyword("dev_loss_tmo", &hw_dev_loss_handler, &snprint_hw_dev_loss);
 	install_sublevel_end();
 
 	install_keyword_root("multipaths", &multipaths_handler);
Index: multipath-tools-100322/libmultipath/config.h
===================================================================
--- multipath-tools-100322.orig/libmultipath/config.h
+++ multipath-tools-100322/libmultipath/config.h
@@ -31,6 +31,8 @@ struct hwentry {
 	int minio;
 	int pg_timeout;
 	int flush_on_last_del;
+	int fast_io_fail;
+	unsigned int dev_loss;
 	char * bl_product;
 };
 
@@ -75,6 +77,8 @@ struct config {
 	int daemon;
 	int flush_on_last_del;
 	int attribute_flags;
+	int fast_io_fail;
+	unsigned int dev_loss;
 	uid_t uid;
 	gid_t gid;
 	mode_t mode;
Index: multipath-tools-100322/libmultipath/propsel.c
===================================================================
--- multipath-tools-100322.orig/libmultipath/propsel.c
+++ multipath-tools-100322/libmultipath/propsel.c
@@ -446,6 +446,48 @@ select_pg_timeout(struct multipath *mp)
 }
 
 extern int
+select_fast_io_fail(struct multipath *mp)
+{
+	if (mp->hwe && mp->hwe->fast_io_fail) {
+		mp->fast_io_fail = mp->hwe->fast_io_fail;
+		if (mp->fast_io_fail == -1)
+			condlog(3, "%s: fast_io_fail_tmo = off (controller default)", mp->alias);
+		else
+			condlog(3, "%s: fast_io_fail_tmo = %d (controller default)", mp->alias, mp->fast_io_fail);
+		return 0;
+	}
+	if (conf->fast_io_fail) {
+		mp->fast_io_fail = conf->fast_io_fail;
+		if (mp->fast_io_fail == -1)
+			condlog(3, "%s: fast_io_fail_tmo = off (config file default)", mp->alias);
+		else
+			condlog(3, "%s: fast_io_fail_tmo = %d (config file default)", mp->alias, mp->fast_io_fail);
+		return 0;
+	}
+	mp->fast_io_fail = 0;
+	return 0;
+}
+
+extern int
+select_dev_loss(struct multipath *mp)
+{
+	if (mp->hwe && mp->hwe->dev_loss) {
+		mp->dev_loss = mp->hwe->dev_loss;
+		condlog(3, "%s: dev_loss_tmo = %u (controller default)",
+			mp->alias, mp->dev_loss);
+		return 0;
+	}
+	if (conf->dev_loss) {
+		mp->dev_loss = conf->dev_loss;
+		condlog(3, "%s: dev_loss_tmo = %u (config file default)",
+			mp->alias, mp->dev_loss);
+		return 0;
+	}
+	mp->dev_loss = 0;
+	return 0;
+}
+
+extern int
 select_flush_on_last_del(struct multipath *mp)
 {
 	if (mp->flush_on_last_del == FLUSH_IN_PROGRESS)
Index: multipath-tools-100322/libmultipath/structs.h
===================================================================
--- multipath-tools-100322.orig/libmultipath/structs.h
+++ multipath-tools-100322/libmultipath/structs.h
@@ -166,6 +166,8 @@ struct multipath {
 	int pg_timeout;
 	int flush_on_last_del;
 	int attribute_flags;
+	int fast_io_fail;
+	unsigned int dev_loss;
 	uid_t uid;
 	gid_t gid;
 	mode_t mode;
Index: multipath-tools-100322/libmultipath/configure.c
===================================================================
--- multipath-tools-100322.orig/libmultipath/configure.c
+++ multipath-tools-100322/libmultipath/configure.c
@@ -70,7 +70,10 @@ setup_map (struct multipath * mpp)
 	select_mode(mpp);
 	select_uid(mpp);
 	select_gid(mpp);
+	select_fast_io_fail(mpp);
+	select_dev_loss(mpp);
 
+	sysfs_set_scsi_tmo(mpp);
 	/*
 	 * assign paths to path groups -- start with no groups and all paths
 	 * in mpp->paths
Index: multipath-tools-100322/libmultipath/discovery.c
===================================================================
--- multipath-tools-100322.orig/libmultipath/discovery.c
+++ multipath-tools-100322/libmultipath/discovery.c
@@ -204,6 +204,43 @@ sysfs_get_fc_nodename (struct sysfs_devi
 	return 1;
 }
 
+int
+sysfs_set_scsi_tmo (struct multipath *mpp)
+{
+	char attr_path[SYSFS_PATH_SIZE];
+	struct path *pp;
+	int i;
+	char value[11];
+
+	if (!mpp->dev_loss && !mpp->fast_io_fail)
+		return 0;
+	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;
+		}
+		if (mpp->dev_loss){
+			snprintf(value, 11, "%u", mpp->dev_loss);
+ 			if (sysfs_attr_set_value(attr_path, "dev_loss_tmo",
+						 value))
+				return 1;
+		}
+		if (mpp->fast_io_fail){
+			if (mpp->fast_io_fail == -1)
+				sprintf(value, "off");
+			else
+				snprintf(value, 11, "%u", mpp->fast_io_fail);
+			if (sysfs_attr_set_value(attr_path, "fast_io_fail",
+						 value))
+				return 1;
+		}
+	}
+	return 0;
+}
+
 static int
 opennode (char * dev, int mode)
 {
Index: multipath-tools-100322/libmultipath/propsel.h
===================================================================
--- multipath-tools-100322.orig/libmultipath/propsel.h
+++ multipath-tools-100322/libmultipath/propsel.h
@@ -15,3 +15,5 @@ int select_minio(struct multipath *mp);
 int select_mode(struct multipath *mp);
 int select_uid(struct multipath *mp);
 int select_gid(struct multipath *mp);
+int select_fast_io_fail(struct multipath *mp);
+int select_dev_loss(struct multipath *mp);
Index: multipath-tools-100322/libmultipath/discovery.h
===================================================================
--- multipath-tools-100322.orig/libmultipath/discovery.h
+++ multipath-tools-100322/libmultipath/discovery.h
@@ -33,6 +33,7 @@ int path_offline (struct path *);
 int pathinfo (struct path *, vector hwtable, int mask);
 struct path * store_pathinfo (vector pathvec, vector hwtable,
 			      char * devname, int flag);
+int sysfs_set_scsi_tmo (struct multipath *mpp);
 
 /*
  * discovery bitmask
Index: multipath-tools-100322/libmultipath/sysfs.c
===================================================================
--- multipath-tools-100322.orig/libmultipath/sysfs.c
+++ multipath-tools-100322/libmultipath/sysfs.c
@@ -356,6 +356,62 @@ void sysfs_device_put(struct sysfs_devic
 	return;
 }
 
+int
+sysfs_attr_set_value(const char *devpath, const char *attr_name,
+		     const char *value)
+{
+	char path_full[PATH_SIZE];
+	int sysfs_len;
+	struct stat statbuf;
+	int fd, value_len, ret = -1;
+
+	dbg("open '%s'/'%s'", devpath, attr_name);
+	sysfs_len = snprintf(path_full, PATH_SIZE, "%s%s/%s", sysfs_path,
+			     devpath, attr_name);
+	if (sysfs_len >= PATH_SIZE || sysfs_len < 0) {
+		if (sysfs_len < 0)
+			dbg("cannot copy sysfs path %s%s/%s : %s", sysfs_path,
+			    devpath, attr_name, strerror(errno));
+		else
+			dbg("sysfs_path %s%s/%s too large", sysfs_path,
+			    devpath, attr_name);
+		goto out;
+	}
+
+	if (stat(path_full, &statbuf) != 0) {
+		dbg("stat '%s' failed: %s" path_full, strerror(errno));
+		goto out;
+	}
+
+	/* skip directories */
+        if (S_ISDIR(statbuf.st_mode))
+                goto out;
+
+	if ((statbuf.st_mode & S_IWUSR) == 0)
+		goto out;
+
+	fd = open(path_full, O_WRONLY);
+	if (fd < 0) {
+		dbg("attribute '%s' can not be opened: %s",
+		    path_full, strerror(errno));
+		goto out;
+	}
+	value_len = strlen(value) + 1;
+	ret = write(fd, value, value_len);
+	if (ret == value_len)
+		ret = 0;
+	else if (ret < 0)
+		dbg("write to %s failed: %s", path_full, strerror(errno));
+	else {
+		dbg("tried to write %d to %s. Wrote %d\n", value_len,
+		    path_full, ret);
+		ret = -1;
+	}
+out:
+	return ret;
+}
+
+
 char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
 {
 	char path_full[PATH_SIZE];
Index: multipath-tools-100322/libmultipath/sysfs.h
===================================================================
--- multipath-tools-100322.orig/libmultipath/sysfs.h
+++ multipath-tools-100322/libmultipath/sysfs.h
@@ -22,5 +22,6 @@ void sysfs_device_put(struct sysfs_devic
 char *sysfs_attr_get_value(const char *devpath, const char *attr_name);
 int sysfs_resolve_link(char *path, size_t size);
 int sysfs_get_size (struct sysfs_device * dev, unsigned long long * size);
-
+int sysfs_attr_set_value(const char *devpath, const char *attr_name,
+			 const char *value);
 #endif

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-08-03 18:15 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-07-30  9:13 [PATCH] multipath: add fast_io_fail and dev_loss_tmo config parameters Jun'ichi Nomura
2010-08-03  1:18 ` Jun'ichi Nomura
2010-08-03 18:15 ` Benjamin Marzinski
  -- strict thread matches above, loose matches on Subject: below --
2010-03-23  2:44 Benjamin Marzinski

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