lib/device/dev-cache.c | 19 +++++++++++++++++++

 lib/device/dev-cache.h |  3 +++

 lib/device/dev-md.c    |  6 +++---

 lib/label/label.c      | 27 ++++++++++++++-------------

 tools/pvscan.c         |  7 +++++++

 5 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c

index 1492181..980dd3c 100644

--- a/lib/device/dev-cache.c

+++ b/lib/device/dev-cache.c

@@ -15,6 +15,7 @@

 #include "base/memory/zalloc.h"

 #include "lib/misc/lib.h"

+#include "lib/device/dev-type.h"

 #include "lib/datastruct/btree.h"

 #include "lib/config/config.h"

 #include "lib/commands/toolcontext.h"

@@ -1634,3 +1635,21 @@ const char *dev_name(const struct device *dev)

 	return (dev && dev->aliases.n) ? dm_list_item(dev->aliases.n, struct dm_str_list)->str :

 	    unknown_device_name();

 }

+

+bool dev_cache_has_md_with_end_superblock(struct dev_types *dt)

+{

+	struct btree_iter *iter = btree_first(_cache.devices);

+	struct device *dev;

+

+	while (iter) {

+		dev = btree_get_data(iter);

+

+		if (dev_is_md_with_end_superblock(dt, dev))

+			return true;

+

+		iter = btree_next(iter);

+	}

+

+	return false;

+}

+

diff --git a/lib/device/dev-cache.h b/lib/device/dev-cache.h

index 8a1c277..46c86c2 100644

--- a/lib/device/dev-cache.h

+++ b/lib/device/dev-cache.h

@@ -17,6 +17,7 @@

 #define _LVM_DEV_CACHE_H

 #include "lib/device/device.h"

+#include "lib/device/dev-type.h"

 #include "lib/misc/lvm-wrappers.h"

 struct cmd_context;

@@ -71,4 +72,6 @@ void dev_reset_error_count(struct cmd_context *cmd);

 void dev_cache_failed_path(struct device *dev, const char *path);

+bool dev_cache_has_md_with_end_superblock(struct dev_types *dt);

+

 #endif

diff --git a/lib/device/dev-md.c b/lib/device/dev-md.c

index 08143b7..9d0a363 100644

--- a/lib/device/dev-md.c

+++ b/lib/device/dev-md.c

@@ -302,12 +302,12 @@ static int _md_sysfs_attribute_scanf(struct dev_types *dt,

 		return ret;

 	if (!(fp = fopen(path, "r"))) {

-		log_sys_error("fopen", path);

+		log_debug("_md_sysfs_attribute_scanf fopen failed %s", path);

 		return ret;

 	}

 	if (!fgets(buffer, sizeof(buffer), fp)) {

-		log_sys_error("fgets", path);

+		log_debug("_md_sysfs_attribute_scanf fgets failed %s", path);

 		goto out;

 	}

@@ -449,7 +449,7 @@ int dev_is_md_with_end_superblock(struct dev_types *dt, struct device *dev)

 	if (_md_sysfs_attribute_scanf(dt, dev, attribute,

 				      "%s", &version_string) != 1)

-		return -1;

+		return 0;

 	log_very_verbose("Device %s %s is %s.",

 			 dev_name(dev), attribute, version_string);

diff --git a/lib/label/label.c b/lib/label/label.c

index a8d87ec..4c21d97 100644

--- a/lib/label/label.c

+++ b/lib/label/label.c

@@ -901,6 +901,20 @@ int label_scan(struct cmd_context *cmd)

 	dev_cache_scan();

 	/*

+	 * If we know that there will be md components with an end

+	 * superblock, then enable the full md filter before label

+	 * scan begins.  FIXME: we could skip the full md check on

+	 * devs that are not identified as PVs, but then we'd need

+	 * to do something other than using the standard md filter.

+	 */

+	if (cmd->md_component_detection && !cmd->use_full_md_check &&

+	    !strcmp(cmd->md_component_checks, "auto") &&

+	    dev_cache_has_md_with_end_superblock(cmd->dev_types)) {

+		log_debug("Enable full md component check.");

+		cmd->use_full_md_check = 1;

+	}

+

+	/*

 	 * Set up the iterator that is needed to step through each device in

 	 * dev cache.

 	 */

@@ -938,19 +952,6 @@ int label_scan(struct cmd_context *cmd)

 			bcache_invalidate_fd(scan_bcache, dev->bcache_fd);

 			_scan_dev_close(dev);

 		}

-

-		/*

-		 * When md devices exist that use the old superblock at the

-		 * end of the device, then in order to detect and filter out

-		 * the component devices of those md devs, we enable the full

-		 * md filter which scans both the start and the end of every

-		 * device.  This doubles the amount of scanning i/o, which we

-		 * want to avoid.  FIXME: this forces start+end scanning of

-		 * every device, but it would be more efficient to limit the

-		 * end scan only to PVs.

-		 */

-		if (dev_is_md_with_end_superblock(cmd->dev_types, dev))

-			cmd->use_full_md_check = 1;

 	};

 	dev_iter_destroy(iter);

diff --git a/tools/pvscan.c b/tools/pvscan.c

index db813ad..0a91add 100644

--- a/tools/pvscan.c

+++ b/tools/pvscan.c

@@ -938,6 +938,13 @@ int pvscan_cache_cmd(struct cmd_context *cmd, int argc, char **argv)

 	/* Creates a list of dev names from /dev, sysfs, etc; does not read any. */

 	dev_cache_scan();

+	if (cmd->md_component_detection && !cmd->use_full_md_check &&

+	    !strcmp(cmd->md_component_checks, "auto") &&

+	    dev_cache_has_md_with_end_superblock(cmd->dev_types)) {

+		log_debug("Enable full md component check.");

+		cmd->use_full_md_check = 1;

+	}

+

 	/*

 	 * For each device command arg (from either position or --major/--minor),

 	 * decide if that device is being added to the system (a dev node exists