devices: fix name handlingdev-dct-devs3

- Fix cases where incorrect device paths were left
  on the dev->aliases list.  Leaving incorrect paths
  on dev->aliases could result in using the wrong device.

- Fix a widespread incorrect assumption that dev_name()
  always returns a valid path (or NULL).  dev_name()
  returns "[unknown]" when there are no paths to a
  device, and is mainly meant to be used in messages.

- Check for valid dev paths in cases that want to use
  the from dev_name() for things other than a message.

1 files changed, 25 insertions, 4 deletions

diff --git a/lib/label/label.c b/lib/label/label.c
index fe2bc8fec..ffb393891 100644
--- a/lib/label/label.c
+++ b/lib/label/label.c
@@ -1130,11 +1130,12 @@ int label_scan_vg_online(struct cmd_context *cmd, const char *vgname,
 	 * sure to find the device.
 	 */
 	if (try_dev_scan) {
+		log_debug("Repeat dev cache scan to translate devnos.");
 		dev_cache_scan(cmd);
 		dm_list_iterate_items(po, &pvs_online) {
 			if (po->dev)
 				continue;
-			if (!(po->dev = dev_cache_get_by_devt(cmd, po->devno, NULL, NULL))) {
+			if (!(po->dev = dev_cache_get_by_devt(cmd, po->devno))) {
 				log_error("No device found for %d:%d PVID %s",
 					  (int)MAJOR(po->devno), (int)MINOR(po->devno), po->pvid);
 				goto bad;
@@ -1722,7 +1723,7 @@ void label_scan_invalidate_lv(struct cmd_context *cmd, struct logical_volume *lv
 	if (lv_info(cmd, lv, 0, &lvinfo, 0, 0) && lvinfo.exists) {
 		/* FIXME: Still unclear what is it supposed to find */
 		devt = MKDEV(lvinfo.major, lvinfo.minor);
-		if ((dev = dev_cache_get_by_devt(cmd, devt, NULL, NULL)))
+		if ((dev = dev_cache_get_by_devt(cmd, devt)))
 			label_scan_invalidate(dev);
 	}
 }
@@ -1736,13 +1737,19 @@ void label_scan_invalidate_lvs(struct cmd_context *cmd, struct dm_list *lvs)
 	struct lv_list *lvl;
 	dev_t devt;
 
+	/*
+	 * FIXME: this is all unnecessary unless there are PVs stacked on LVs,
+	 * so we can skip all of this if scan_lvs=0.
+	 */
+	log_debug("invalidating devs for any pvs on lvs");
+
 	if (get_device_list(NULL, &devs, &devs_features)) {
 		if (devs_features & DM_DEVICE_LIST_HAS_UUID) {
 			dm_list_iterate_items(dm_dev, devs)
 				if (dm_dev->uuid &&
 				    strncmp(dm_dev->uuid, UUID_PREFIX, sizeof(UUID_PREFIX) - 1) == 0) {
 					devt = MKDEV(dm_dev->major, dm_dev->minor);
-					if ((dev = dev_cache_get_by_devt(cmd, devt, NULL, NULL)))
+					if ((dev = dev_cache_get_by_devt(cmd, devt)))
 						label_scan_invalidate(dev);
 				}
 			/* ATM no further caching for any lvconvert command
@@ -1879,10 +1886,24 @@ int label_scan_open_rw(struct device *dev)
 
 int label_scan_reopen_rw(struct device *dev)
 {
+	const char *name;
 	int flags = 0;
 	int prev_fd = dev->bcache_fd;
 	int fd;
 
+	if (dm_list_empty(&dev->aliases)) {
+		log_error("Cannot reopen rw device %d:%d with no valid paths di %d fd %d.",
+			  (int)MAJOR(dev->dev), (int)MINOR(dev->dev), dev->bcache_di, dev->bcache_fd);
+		return 0;
+	}
+
+	name = dev_name(dev);
+	if (!name || name[0] != '/') {
+		log_error("Cannot reopen rw device %d:%d with no valid name di %d fd %d.",
+			  (int)MAJOR(dev->dev), (int)MINOR(dev->dev), dev->bcache_di, dev->bcache_fd);
+		return 0;
+	}
+
 	if (!(dev->flags & DEV_IN_BCACHE)) {
 		if ((dev->bcache_fd != -1) || (dev->bcache_di != -1)) {
 			/* shouldn't happen */
@@ -1912,7 +1933,7 @@ int label_scan_reopen_rw(struct device *dev)
 	flags |= O_NOATIME;
 	flags |= O_RDWR;
 
-	fd = open(dev_name(dev), flags, 0777);
+	fd = open(name, flags, 0777);
 	if (fd < 0) {
 		log_error("Failed to open rw %s errno %d di %d fd %d.",
 			  dev_name(dev), errno, dev->bcache_di, dev->bcache_fd);