Skip to contentSkip to conversation

multipath: make devt2devname use lstat to check sysfs links

PATCH In review Benjamin Marzinski 2 participants 2 messages Jan 10, 2013 – Jan 11, 2013 Device mapper

lore
Share & tools
lore

Benjamin Marzinski

author maintainer
#0 lore raw

PATCH v2 1/1 multipath: make devt2devname use lstat to check sysfs links

dm_reassign wasn't working correctly for me because devt2devname used stat() to check if /sys/dev/block/major:minor was a symlink. But stat() never returns a symlink, if follows it. It needs to use lstat() instead. Also, I made multipath log a message when a dm device gets reassigned to use multipath.

Signed-off-by Benjamin Marzinski <[email protected]>
---
 libmultipath/devmapper.c |    4 +++-
 libmultipath/sysfs.c     |    6 ++++--
 libmultipath/util.c      |    3 ++-
 3 files changed, 9 insertions(+), 4 deletions(-)
libmultipath/devmapper.c +3 -1
Index: multipath-tools-130109/libmultipath/devmapper.c
===================================================================
@@ -1394,8 +1394,10 @@ int dm_reassign(const char *mapname)
 		return 1;
 	}
 
-	if (!(dmt = dm_task_create(DM_DEVICE_DEPS)))
+	if (!(dmt = dm_task_create(DM_DEVICE_DEPS))) {
+		condlog(3, "%s: couldn't make dm task", mapname);
 		return 0;
+	}
 
 	if (!dm_task_set_name(dmt, mapname))
 		goto out;
libmultipath/sysfs.c +4 -2
Index: multipath-tools-130109/libmultipath/sysfs.c
===================================================================
@@ -125,8 +125,10 @@ int sysfs_check_holders(char * check_dev
 		return 0;
 	}
 
-	if (devt2devname(check_dev, PATH_SIZE, check_devt))
+	if (devt2devname(check_dev, PATH_SIZE, check_devt)) {
+		condlog(1, "can't get devname for %s", check_devt);
 		return 0;
+	}
 
 	condlog(3, "%s: checking holder", check_dev);
 

@@ -153,7 +155,7 @@ int sysfs_check_holders(char * check_dev
 		}
 		table_name = dm_mapname(major, table_minor);
 
-		condlog(3, "%s: reassign table %s old %s new %s", check_dev,
+		condlog(0, "%s: reassign table %s old %s new %s", check_dev,
 			table_name, check_devt, new_devt);
 
 		dm_reassign_table(table_name, check_devt, new_devt);
libmultipath/util.c +2 -1
Index: multipath-tools-130109/libmultipath/util.c
===================================================================
@@ -161,6 +161,7 @@ devt2devname (char *devname, int devname
 	struct stat statbuf;
 
 	memset(block_path, 0, sizeof(block_path));
+	memset(dev, 0, sizeof(dev));
 	if (sscanf(devt, "%u:%u", &major, &minor) != 2) {
 		condlog(0, "Invalid device number %s", devt);
 		return 1;

@@ -172,7 +173,7 @@ devt2devname (char *devname, int devname
 	if (stat("/sys/dev/block", &statbuf) == 0) {
 		/* Newer kernels have /sys/dev/block */
 		sprintf(block_path,"/sys/dev/block/%u:%u", major, minor);
-		if (stat(block_path, &statbuf) == 0) {
+		if (lstat(block_path, &statbuf) == 0) {
 			if (S_ISLNK(statbuf.st_mode) &&
 			    readlink(block_path, dev, FILE_NAME_SIZE) > 0) {
 				char *p = strrchr(dev, '/');
Acked-by on v2 1/1
#1 lore raw
Quoted 6 lines · Benjamin Marzinski

dm_reassign wasn't working correctly for me because devt2devname used stat() to check if /sys/dev/block/major:minor was a symlink. But stat() never returns a symlink, if follows it. It needs to use lstat() instead. Also, I made multipath log a message when a dm device gets reassigned to use multipath.

Signed-off-by Benjamin Marzinski <[email protected]>
Acked-by Hannes Reinecke <[email protected]>

Cheers,

Hannes

Signature · 4 lines
Dr. Hannes Reinecke		      zSeries & Storage
[email protected]			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)