Blame SOURCES/lvm2-2_03_12-devs-remove-invalid-path-name-aliases.patch

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 lib/device/dev-cache.c    | 161 ++++++++++++++++++++++++++++++++++++----------
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 test/shell/dev-aliases.sh |  53 +++++++++++++++
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 2 files changed, 179 insertions(+), 35 deletions(-)
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 create mode 100644 test/shell/dev-aliases.sh
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diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
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index d5f18ff..8082efa 100644
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--- a/lib/device/dev-cache.c
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+++ b/lib/device/dev-cache.c
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@@ -1428,60 +1428,151 @@ struct device *dev_hash_get(const char *name)
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 	return (struct device *) dm_hash_lookup(_cache.names, name);
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 }
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+static void _remove_alias(struct device *dev, const char *name)
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+{
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+	struct dm_str_list *strl;
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+
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+	dm_list_iterate_items(strl, &dev->aliases) {
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+		if (!strcmp(strl->str, name)) {
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+			dm_list_del(&strl->list);
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+			return;
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+		}
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+	}
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+}
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+
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+/*
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+ * Check that paths for this dev still refer to the same dev_t.  This is known
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+ * to drop invalid paths in the case where lvm deactivates an LV, which causes
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+ * that LV path to go away, but that LV path is not removed from dev-cache (it
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+ * probably should be).  Later a new path to a different LV is added to
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+ * dev-cache, where the new LV has the same major:minor as the previously
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+ * deactivated LV.  The new LV will find the existing struct dev, and that
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+ * struct dev will have dev->aliases entries that refer to the name of the old
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+ * deactivated LV.  Those old paths are all invalid and are dropped here.
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+ */
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+
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+static void _verify_aliases(struct device *dev, const char *newname)
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+{
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+	struct dm_str_list *strl, *strl2;
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+	struct stat st;
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+
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+	dm_list_iterate_items_safe(strl, strl2, &dev->aliases) {
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+		/* newname was just stat'd and added by caller */
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+		if (newname && !strcmp(strl->str, newname))
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+			continue;
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+
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+		if (stat(strl->str, &st) || (st.st_rdev != dev->dev)) {
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+			log_debug("Drop invalid path %s for %d:%d (new path %s).",
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+				  strl->str, (int)MAJOR(dev->dev), (int)MINOR(dev->dev), newname ?: "");
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+			dm_hash_remove(_cache.names, strl->str);
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+			dm_list_del(&strl->list);
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+		}
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+	}
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+}
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+
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 struct device *dev_cache_get(struct cmd_context *cmd, const char *name, struct dev_filter *f)
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 {
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-	struct stat buf;
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-	struct device *d = (struct device *) dm_hash_lookup(_cache.names, name);
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-	int info_available = 0;
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-	int ret = 1;
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+	struct device *dev = (struct device *) dm_hash_lookup(_cache.names, name);
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+	struct stat st;
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+	int ret;
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-	if (d && (d->flags & DEV_REGULAR))
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-		return d;
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+	/*
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+	 * DEV_REGULAR means that is "dev" is actually a file, not a device.
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+	 * FIXME: I don't think dev-cache is used for files any more and this
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+	 * can be dropped?
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+	 */
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+	if (dev && (dev->flags & DEV_REGULAR))
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+		return dev;
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+
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+	/*
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+	 * The requested path is invalid, remove any dev-cache
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+	 * info for it.
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+	 */
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+	if (stat(name, &st)) {
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+		if (dev) {
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+			log_print("Device path %s is invalid for %d:%d %s.",
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+				  name, (int)MAJOR(dev->dev), (int)MINOR(dev->dev), dev_name(dev));
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-	/* If the entry's wrong, remove it */
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-	if (stat(name, &buf) < 0) {
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-		if (d)
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 			dm_hash_remove(_cache.names, name);
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-		log_sys_very_verbose("stat", name);
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-		d = NULL;
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-	} else
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-		info_available = 1;
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-	if (d && (buf.st_rdev != d->dev)) {
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-		dm_hash_remove(_cache.names, name);
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-		d = NULL;
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-	}
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+			_remove_alias(dev, name);
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-	if (!d) {
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-		_insert(name, info_available ? &buf : NULL, 0, obtain_device_list_from_udev());
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-		d = (struct device *) dm_hash_lookup(_cache.names, name);
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-		if (!d) {
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-			log_debug_devs("Device name not found in dev_cache repeat dev_cache_scan for %s", name);
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-			dev_cache_scan();
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-			d = (struct device *) dm_hash_lookup(_cache.names, name);
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+			/* Remove any other names in dev->aliases that are incorrect. */
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+			_verify_aliases(dev, NULL);
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 		}
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+		return NULL;
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 	}
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-	if (!d)
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+	if (!S_ISBLK(st.st_mode)) {
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+		log_debug("Not a block device %s.", name);
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 		return NULL;
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+	}
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-	if (d && (d->flags & DEV_REGULAR))
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-		return d;
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+	/*
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+	 * dev-cache has incorrect info for the requested path.
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+	 * Remove incorrect info and then add new dev-cache entry.
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+	 */
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+	if (dev && (st.st_rdev != dev->dev)) {
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+		log_print("Device path %s does not match %d:%d %s.",
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+			  name, (int)MAJOR(dev->dev), (int)MINOR(dev->dev), dev_name(dev));
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+
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+		dm_hash_remove(_cache.names, name);
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+
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+		_remove_alias(dev, name);
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+
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+		/* Remove any other names in dev->aliases that are incorrect. */
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+		_verify_aliases(dev, NULL);
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+
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+		/* Add new dev-cache entry next. */
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+		dev = NULL;
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+	}
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+
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+	/*
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+	 * Either add a new struct dev for st_rdev and name,
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+	 * or add name as a new alias for an existing struct dev
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+	 * for st_rdev.
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+	 */
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+	if (!dev) {
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+		_insert_dev(name, st.st_rdev);
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-	if (f && !(d->flags & DEV_REGULAR)) {
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-		ret = f->passes_filter(cmd, f, d, NULL);
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+		/* Get the struct dev that was just added. */
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+		dev = (struct device *) dm_hash_lookup(_cache.names, name);
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-		if (ret == -EAGAIN) {
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-			log_debug_devs("get device by name defer filter %s", dev_name(d));
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-			d->flags |= DEV_FILTER_AFTER_SCAN;
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-			ret = 1;
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+		if (!dev) {
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+			log_error("Failed to get device %s", name);
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+			return NULL;
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 		}
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+
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+		_verify_aliases(dev, name);
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 	}
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-	if (f && !(d->flags & DEV_REGULAR) && !ret)
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+	/*
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+	 * The caller passed a filter if they only want the dev if it
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+	 * passes filters.
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+	 */
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+
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+	if (!f)
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+		return dev;
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+
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+	ret = f->passes_filter(cmd, f, dev, NULL);
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+
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+	/*
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+	 * This might happen if this function is called before
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+	 * filters can do i/o.  I don't think this will happen
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+	 * any longer and this EAGAIN case can be removed.
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+	 */
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+	if (ret == -EAGAIN) {
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+		log_debug_devs("dev_cache_get filter deferred %s", dev_name(dev));
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+		dev->flags |= DEV_FILTER_AFTER_SCAN;
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+		ret = 1;
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+	}
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+
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+	if (!ret) {
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+		log_debug_devs("dev_cache_get filter excludes %s", dev_name(dev));
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 		return NULL;
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+	}
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-	return d;
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+	return dev;
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 }
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 static struct device *_dev_cache_seek_devt(dev_t dev)
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diff --git a/test/shell/dev-aliases.sh b/test/shell/dev-aliases.sh
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new file mode 100644
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index 0000000..c97cd5d
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--- /dev/null
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+++ b/test/shell/dev-aliases.sh
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@@ -0,0 +1,53 @@
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+#!/usr/bin/env bash
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+
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+# Copyright (C) 2012 Red Hat, Inc. All rights reserved.
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+#
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+# This copyrighted material is made available to anyone wishing to use,
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+# modify, copy, or redistribute it subject to the terms and conditions
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+# of the GNU General Public License v.2.
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+#
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+# You should have received a copy of the GNU General Public License
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+# along with this program; if not, write to the Free Software Foundation,
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+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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+
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+SKIP_WITH_LVMPOLLD=1
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+
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+. lib/inittest
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+
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+aux prepare_devs 3
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+
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+vgcreate $vg $dev1 $dev2 $dev3
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+
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+#
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+# This lvconvert command will deactivate LV1, then internally create a new
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+# lv, lvol0, as a poolmetadataspare, then activate lvol0 to zero it.
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+# lvol0 will get the same major:minor that LV1 had.  When the code gets
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+# the struct dev for lvol0, the new path to lvol0 is added to the
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+# dev-cache with it's major:minor.  That major:minor already exists in
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+# dev-cache and has the stale LV1 as an alias.  So the path to lvol0 is
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+# added as an alias to the existing struct dev (with the correct
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+# major:minor), but that struct dev has the stale LV1 path on its aliases
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+# list.  The code will now validate all the aliases before returning the
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+# dev for lvol0, and will find that the LV1 path is stale and remove it
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+# from the aliases.  That will prevent the stale path from being used for
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+# the dev in place of the new path.
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+#
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+# The preferred_name is set to /dev/mapper so that if the stale path still
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+# exists, that stale path would be used as the name for the dev, and the
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+# wiping code would fail to open that stale name.
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+#
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+
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+lvcreate -n $lv1 -L32M $vg $dev1
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+lvcreate -n $lv2 -L16M $vg $dev2
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+lvconvert -y --type cache-pool --poolmetadata $lv2 --cachemode writeback $vg/$lv1 --config='devices { preferred_names=["/dev/mapper/"] }' 
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+lvremove -y $vg/$lv1
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+
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+lvcreate -n $lv1 -L32M $vg $dev1
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+lvcreate -n $lv2 -L16M $vg $dev2
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+lvconvert -y --type cache-pool --poolmetadata $lv2 $vg/$lv1
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+lvremove -y $vg/$lv1
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+
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+# TODO: add more validation of dev aliases being specified as command
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+# args in combination with various preferred_names settings.
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+
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+vgremove -ff  $vg