From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Benjamin Marzinski <bmarzins@redhat.com>

Date: Thu, 28 Mar 2019 15:17:48 -0500

Subject: [PATCH] multipathd: Don't use fallback code after getting wwid

The fallback code is necessary to set up mutipath devices, if multipath

temporarily can't get the information from udev.  However, once the

devices are set up, udev is the definitive source of this information.

The wwid gotten from the fallback code and the udev code should always

be the same, in which case it doesn't matter where we get the wwid

from. But if they are different, it's important to try to do the

right thing.

Working under the assumption that udev will either never give us this

information, or that it usually will. multipath should assume that if

there are multiple paths to a device, either they will all never get

a wwid from udev, or some of them will likely already have gotten the

correct wwid from udev.  In this case, we should fix this as soon as

possible.

This does mean that devices where udev will never give out the uuid

will not notice if the wwid changes, but that's a small price to pay

for doing the right thing most of the time.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>

---

 libmultipath/discovery.c | 22 +++++++++-------------

 libmultipath/discovery.h |  3 ++-

 multipathd/main.c        |  2 +-

 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c

index 3ec60d6..744cf2c 100644

--- a/libmultipath/discovery.c

+++ b/libmultipath/discovery.c

@@ -1763,7 +1763,6 @@ static ssize_t uid_fallback(struct path *pp, int path_state,

 	    !strcmp(pp->uid_attribute, DEFAULT_UID_ATTRIBUTE)) {

 		len = get_vpd_uid(pp);

 		*origin = "sysfs";

-		pp->uid_attribute = NULL;

 		if (len < 0 && path_state == PATH_UP) {

 			condlog(1, "%s: failed to get sysfs uid: %s",

 				pp->dev, strerror(-len));

@@ -1787,7 +1786,6 @@ static ssize_t uid_fallback(struct path *pp, int path_state,

 			len = WWID_SIZE;

 		}

 		*origin = "sysfs";

-		pp->uid_attribute = NULL;

 	}

 	return len;

 }

@@ -1800,12 +1798,14 @@ static int has_uid_fallback(struct path *pp)

 }

 int

-get_uid (struct path * pp, int path_state, struct udev_device *udev)

+get_uid (struct path * pp, int path_state, struct udev_device *udev,

+	 int allow_fallback)

 {

 	char *c;

 	const char *origin = "unknown";

 	ssize_t len = 0;

 	struct config *conf;

+	int used_fallback = 0;

 	if (!pp->uid_attribute && !pp->getuid) {

 		conf = get_multipath_config();

@@ -1846,14 +1846,9 @@ get_uid (struct path * pp, int path_state, struct udev_device *udev)

 			len = get_vpd_uid(pp);

 			origin = "sysfs";

 		}

-		if (len <= 0 && has_uid_fallback(pp)) {

-			int retrigger_tries;

-

-			conf = get_multipath_config();

-			retrigger_tries = conf->retrigger_tries;

-			put_multipath_config(conf);

-			if (pp->retriggers >= retrigger_tries)

-				len = uid_fallback(pp, path_state, &origin);

+		if (len <= 0 && allow_fallback && has_uid_fallback(pp)) {

+			used_fallback = 1;

+			len = uid_fallback(pp, path_state, &origin);

 		}

 	}

 	if ( len < 0 ) {

@@ -1870,7 +1865,7 @@ get_uid (struct path * pp, int path_state, struct udev_device *udev)

 			c--;

 		}

 	}

-	condlog(3, "%s: uid = %s (%s)", pp->dev,

+	condlog((used_fallback)? 1 : 3, "%s: uid = %s (%s)", pp->dev,

 		*pp->wwid == '\0' ? "<empty>" : pp->wwid, origin);

 	return 0;

 }

@@ -1994,7 +1989,8 @@ int pathinfo(struct path *pp, struct config *conf, int mask)

 	}

 	if ((mask & DI_WWID) && !strlen(pp->wwid)) {

-		get_uid(pp, path_state, pp->udev);

+		get_uid(pp, path_state, pp->udev,

+			(pp->retriggers >= conf->retrigger_tries));

 		if (!strlen(pp->wwid)) {

 			if (pp->bus == SYSFS_BUS_UNDEF)

 				return PATHINFO_SKIPPED;

diff --git a/libmultipath/discovery.h b/libmultipath/discovery.h

index 9aacf75..8fd126b 100644

--- a/libmultipath/discovery.h

+++ b/libmultipath/discovery.h

@@ -52,7 +52,8 @@ ssize_t sysfs_get_vpd (struct udev_device * udev, int pg, unsigned char * buff,

 		       size_t len);

 int sysfs_get_asymmetric_access_state(struct path *pp,

 				      char *buff, int buflen);

-int get_uid(struct path * pp, int path_state, struct udev_device *udev);

+int get_uid(struct path * pp, int path_state, struct udev_device *udev,

+	    int allow_fallback);

 /*

  * discovery bitmask

diff --git a/multipathd/main.c b/multipathd/main.c

index e4f95a0..1413c6d 100644

--- a/multipathd/main.c

+++ b/multipathd/main.c

@@ -1227,7 +1227,7 @@ uev_update_path (struct uevent *uev, struct vectors * vecs)

 			goto out;

 		strcpy(wwid, pp->wwid);

-		rc = get_uid(pp, pp->state, uev->udev);

+		rc = get_uid(pp, pp->state, uev->udev, 0);

 		if (rc != 0)

 			strcpy(pp->wwid, wwid);

-- 

2.17.2