bcache: more detailed error message to bcache_device_link()

This patch adds more accurate error message for specific
ssyfs_create_link() call, to help debugging failure during
bcache device start tup.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/super.c

@@ -693,16 +693,21 @@ static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
 {
 	unsigned int i;
 	struct cache *ca;
+	int ret;
 
 	for_each_cache(ca, d->c, i)
 		bd_link_disk_holder(ca->bdev, d->disk);
 
 	snprintf(d->name, BCACHEDEVNAME_SIZE,
 		 "%s%u", name, d->id);
 
-	WARN(sysfs_create_link(&d->kobj, &c->kobj, "cache") ||
-	     sysfs_create_link(&c->kobj, &d->kobj, d->name),
-	     "Couldn't create device <-> cache set symlinks");
+	ret = sysfs_create_link(&d->kobj, &c->kobj, "cache");
+	if (ret < 0)
+		pr_err("Couldn't create device -> cache set symlink");
+
+	ret = sysfs_create_link(&c->kobj, &d->kobj, d->name);
+	if (ret < 0)
+		pr_err("Couldn't create cache set -> device symlink");
 
 	clear_bit(BCACHE_DEV_UNLINK_DONE, &d->flags);
 }