[dm-devel] [PATCH] multipath: fix scsi timeout code

[Benjamin Marzinski <bmarzins redhat com>]

sysfs_attr_set_value() returns the amount written on on success, or -1 on
failure.  sysfs_setc_scsi_tmo() was checking if the return was nonzero, and
failing if it was. This meant that it always failed out silently after writing
the first value. I've changed the check, and added some error messages.  I also
made sysfs_attr_set_value return -1 for all errors.

Signed-off-by: Benjamin Marzinski <bmarzins redhat com>
---
 libmultipath/discovery.c |   11 +++++++++--
 libmultipath/sysfs.c     |    2 +-
 2 files changed, 10 insertions(+), 3 deletions(-)

Index: multipath-tools-111111/libmultipath/discovery.c
===================================================================
--- multipath-tools-111111.orig/libmultipath/discovery.c
+++ multipath-tools-111111/libmultipath/discovery.c
@@ -316,8 +316,11 @@ sysfs_set_scsi_tmo (struct multipath *mp
 		if (mpp->dev_loss){
 			snprintf(value, 11, "%u", mpp->dev_loss);
 			if (sysfs_attr_set_value(attr_path, "dev_loss_tmo",
-						 value, 11))
+						 value, 11) < 0) {
+				condlog(0, "%s failed to set %s/dev_loss_tmo",
+					mpp->alias, attr_path);
 				return 1;
+			}
 		}
 		if (mpp->fast_io_fail){
 			if (mpp->fast_io_fail == -1)
@@ -325,8 +328,12 @@ sysfs_set_scsi_tmo (struct multipath *mp
 			else
 				snprintf(value, 11, "%u", mpp->fast_io_fail);
 			if (sysfs_attr_set_value(attr_path, "fast_io_fail_tmo",
-						 value, 11))
+						 value, 11) < 0) {
+				condlog(0,
+					"%s failed to set %s/fast_io_fail_tmo", 
+					mpp->alias, attr_path);
 				return 1;
+			}
 		}
 	}
 	return 0;
Index: multipath-tools-111111/libmultipath/sysfs.c
===================================================================
--- multipath-tools-111111.orig/libmultipath/sysfs.c
+++ multipath-tools-111111/libmultipath/sysfs.c
@@ -351,7 +351,7 @@ ssize_t sysfs_attr_set_value(const char
 	char path_full[PATH_SIZE];
 	struct stat statbuf;
 	int fd;
-	ssize_t size = 0;
+	ssize_t size = -1;
 	size_t sysfs_len;
 
 	if (!attr_name || !value || !value_len)