[dm-devel] [PATCH 03/21] libmultipath: unify use_existing_alias() and get_user_friendly_alias()

[mwilck@suse.com]

From: Martin Wilck <mwilck@suse.com>

These functions are only called from select_alias(). The logic
is more obvious when unified in a single function.

Signed-off-by: Martin Wilck <mwilck@suse.com>
Cc: David Bond <dbond@suse.com>
---
 libmultipath/alias.c   | 82 ++++++++++++------------------------------
 libmultipath/alias.h   |  9 ++---
 libmultipath/propsel.c | 19 +++++-----
 3 files changed, 34 insertions(+), 76 deletions(-)

diff --git a/libmultipath/alias.c b/libmultipath/alias.c
index abde08c..9b9b789 100644
--- a/libmultipath/alias.c
+++ b/libmultipath/alias.c
@@ -329,13 +329,13 @@ allocate_binding(int fd, const char *wwid, int id, const char *prefix)
 	return alias;
 }
 
-char *
-use_existing_alias (const char *wwid, const char *file, const char *alias_old,
-		    const char *prefix, int bindings_read_only)
+char *get_user_friendly_alias(const char *wwid, const char *file, const char *alias_old,
+			      const char *prefix, bool bindings_read_only)
 {
 	char *alias = NULL;
 	int id = 0;
 	int fd, can_write;
+	bool new_binding = false;
 	char buff[WWID_SIZE];
 	FILE *f;
 
@@ -349,6 +349,10 @@ use_existing_alias (const char *wwid, const char *file, const char *alias_old,
 		close(fd);
 		return NULL;
 	}
+
+	if (!strlen(alias_old))
+		goto new_alias;
+
 	/* lookup the binding. if it exists, the wwid will be in buff
 	 * either way, id contains the id for the alias
 	 */
@@ -358,14 +362,14 @@ use_existing_alias (const char *wwid, const char *file, const char *alias_old,
 		/* if buff is our wwid, it's already
 		 * allocated correctly
 		 */
-		if (strcmp(buff, wwid) == 0)
+		if (strcmp(buff, wwid) == 0) {
 			alias = strdup(alias_old);
-		else {
-			alias = NULL;
+			goto out;
+		} else {
 			condlog(0, "alias %s already bound to wwid %s, cannot reuse",
 				alias_old, buff);
+			goto new_alias;
 		}
-		goto out;
 	}
 
 	id = lookup_binding(f, wwid, &alias, NULL, 0);
@@ -377,8 +381,15 @@ use_existing_alias (const char *wwid, const char *file, const char *alias_old,
 
 	/* allocate the existing alias in the bindings file */
 	id = scan_devname(alias_old, prefix);
-	if (id <= 0)
-		goto out;
+
+new_alias:
+	if (id <= 0) {
+		id = lookup_binding(f, wwid, &alias, prefix, 1);
+		if (id <= 0)
+			goto out;
+		else
+			new_binding = true;
+	}
 
 	if (fflush(f) != 0) {
 		condlog(0, "cannot fflush bindings file stream : %s",
@@ -388,8 +399,9 @@ use_existing_alias (const char *wwid, const char *file, const char *alias_old,
 
 	if (can_write && !bindings_read_only) {
 		alias = allocate_binding(fd, wwid, id, prefix);
-		condlog(0, "Allocated existing binding [%s] for WWID [%s]",
-			alias, wwid);
+		if (alias && !new_binding)
+			condlog(2, "Allocated existing binding [%s] for WWID [%s]",
+				alias, wwid);
 	}
 
 out:
@@ -399,54 +411,6 @@ out:
 	return alias;
 }
 
-char *
-get_user_friendly_alias(const char *wwid, const char *file, const char *prefix,
-			int bindings_read_only)
-{
-	char *alias;
-	int fd, id;
-	FILE *f;
-	int can_write;
-
-	if (!wwid || *wwid == '\0') {
-		condlog(3, "Cannot find binding for empty WWID");
-		return NULL;
-	}
-
-	fd = open_file(file, &can_write, bindings_file_header);
-	if (fd < 0)
-		return NULL;
-
-	f = fdopen(fd, "r");
-	if (!f) {
-		condlog(0, "cannot fdopen on bindings file descriptor : %s",
-			strerror(errno));
-		close(fd);
-		return NULL;
-	}
-
-	id = lookup_binding(f, wwid, &alias, prefix, 1);
-	if (id < 0) {
-		fclose(f);
-		return NULL;
-	}
-
-	pthread_cleanup_push(free, alias);
-
-	if (fflush(f) != 0) {
-		condlog(0, "cannot fflush bindings file stream : %s",
-			strerror(errno));
-		free(alias);
-		alias = NULL;
-	} else if (can_write && !bindings_read_only && !alias)
-		alias = allocate_binding(fd, wwid, id, prefix);
-
-	fclose(f);
-
-	pthread_cleanup_pop(0);
-	return alias;
-}
-
 int
 get_user_friendly_wwid(const char *alias, char *buff, const char *file)
 {
diff --git a/libmultipath/alias.h b/libmultipath/alias.h
index dbc950c..fa33223 100644
--- a/libmultipath/alias.h
+++ b/libmultipath/alias.h
@@ -2,13 +2,10 @@
 #define _ALIAS_H
 
 int valid_alias(const char *alias);
-char *get_user_friendly_alias(const char *wwid, const char *file,
-			      const char *prefix,
-			      int bindings_readonly);
 int get_user_friendly_wwid(const char *alias, char *buff, const char *file);
-char *use_existing_alias (const char *wwid, const char *file,
-			  const char *alias_old,
-			  const char *prefix, int bindings_read_only);
+char *get_user_friendly_alias(const char *wwid, const char *file,
+			      const char *alias_old,
+			      const char *prefix, bool bindings_read_only);
 
 struct config;
 int check_alias_settings(const struct config *);
diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
index d6bce12..354e883 100644
--- a/libmultipath/propsel.c
+++ b/libmultipath/propsel.c
@@ -401,19 +401,16 @@ int select_alias(struct config *conf, struct multipath * mp)
 
 	select_alias_prefix(conf, mp);
 
-	if (strlen(mp->alias_old) > 0) {
-		mp->alias = use_existing_alias(mp->wwid, conf->bindings_file,
-				mp->alias_old, mp->alias_prefix,
-				conf->bindings_read_only);
-		memset (mp->alias_old, 0, WWID_SIZE);
-		origin = "(setting: using existing alias)";
-	}
+	mp->alias = get_user_friendly_alias(mp->wwid, conf->bindings_file,
+					    mp->alias_old, mp->alias_prefix,
+					    conf->bindings_read_only);
 
-	if (mp->alias == NULL) {
-		mp->alias = get_user_friendly_alias(mp->wwid,
-				conf->bindings_file, mp->alias_prefix, conf->bindings_read_only);
+	if (mp->alias && !strncmp(mp->alias, mp->alias_old, WWID_SIZE))
+		origin = "(setting: using existing alias)";
+	else if (mp->alias)
 		origin = "(setting: user_friendly_name)";
-	}
+	memset (mp->alias_old, 0, WWID_SIZE);
+
 out:
 	if (mp->alias == NULL) {
 		mp->alias = strdup(mp->wwid);
-- 
2.41.0

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