From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Benjamin Marzinski <bmarzins@redhat.com>

Date: Tue, 23 Jun 2020 22:17:31 -0500

Subject: [PATCH] libmultipath: make dm_get_map/status return codes symbolic

dm_get_map() and dm_get_status() now use symbolic return codes. They

also differentiate between failing to get information from device-mapper

and not finding the requested device. These symboilc return codes are

also used by update_multipath_* functions.

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

---

 libmultipath/devmapper.c   | 51 +++++++++++++++++++++++++-------------

 libmultipath/devmapper.h   |  6 +++++

 libmultipath/structs_vec.c | 45 +++++++++++++++++++--------------

 multipathd/main.c          | 12 ++++-----

 4 files changed, 72 insertions(+), 42 deletions(-)

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

index 13a1cf53..f6204e5f 100644

--- a/libmultipath/devmapper.c

+++ b/libmultipath/devmapper.c

@@ -525,36 +525,43 @@ int dm_map_present(const char * str)

 int dm_get_map(const char *name, unsigned long long *size, char *outparams)

 {

-	int r = 1;

+	int r = DMP_ERR;

 	struct dm_task *dmt;

 	uint64_t start, length;

 	char *target_type = NULL;

 	char *params = NULL;

 	if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))

-		return 1;

+		return r;

 	if (!dm_task_set_name(dmt, name))

 		goto out;

 	dm_task_no_open_count(dmt);

-	if (!dm_task_run(dmt))

+	errno = 0;

+	if (!dm_task_run(dmt)) {

+		if (dm_task_get_errno(dmt) == ENXIO)

+			r = DMP_NOT_FOUND;

 		goto out;

+	}

+	r = DMP_NOT_FOUND;

 	/* Fetch 1st target */

-	dm_get_next_target(dmt, NULL, &start, &length,

-			   &target_type, &params);

+	if (dm_get_next_target(dmt, NULL, &start, &length,

+			       &target_type, &params) != NULL)

+		/* more than one target */

+		goto out;

 	if (size)

 		*size = length;

 	if (!outparams) {

-		r = 0;

+		r = DMP_OK;

 		goto out;

 	}

 	if (snprintf(outparams, PARAMS_SIZE, "%s", params) <= PARAMS_SIZE)

-		r = 0;

+		r = DMP_OK;

 out:

 	dm_task_destroy(dmt);

 	return r;

@@ -628,35 +635,45 @@ is_mpath_part(const char *part_name, const char *map_name)

 int dm_get_status(const char *name, char *outstatus)

 {

-	int r = 1;

+	int r = DMP_ERR;

 	struct dm_task *dmt;

 	uint64_t start, length;

 	char *target_type = NULL;

 	char *status = NULL;

 	if (!(dmt = libmp_dm_task_create(DM_DEVICE_STATUS)))

-		return 1;

+		return r;

 	if (!dm_task_set_name(dmt, name))

 		goto out;

 	dm_task_no_open_count(dmt);

-	if (!dm_task_run(dmt))

+	errno = 0;

+	if (!dm_task_run(dmt)) {

+		if (dm_task_get_errno(dmt) == ENXIO)

+			r = DMP_NOT_FOUND;

 		goto out;

+	}

+	r = DMP_NOT_FOUND;

 	/* Fetch 1st target */

-	dm_get_next_target(dmt, NULL, &start, &length,

-			   &target_type, &status);

+	if (dm_get_next_target(dmt, NULL, &start, &length,

+			       &target_type, &status) != NULL)

+		goto out;

+

+	if (!target_type || strcmp(target_type, TGT_MPATH) != 0)

+		goto out;

+

 	if (!status) {

 		condlog(2, "get null status.");

 		goto out;

 	}

 	if (snprintf(outstatus, PARAMS_SIZE, "%s", status) <= PARAMS_SIZE)

-		r = 0;

+		r = DMP_OK;

 out:

-	if (r)

+	if (r != DMP_OK)

 		condlog(0, "%s: error getting map status string", name);

 	dm_task_destroy(dmt);

@@ -866,7 +883,7 @@ int _dm_flush_map (const char * mapname, int need_sync, int deferred_remove,

 			return 1;

 	if (need_suspend &&

-	    !dm_get_map(mapname, &mapsize, params) &&

+	    dm_get_map(mapname, &mapsize, params) == DMP_OK &&

 	    strstr(params, "queue_if_no_path")) {

 		if (!dm_queue_if_no_path(mapname, 0))

 			queue_if_no_path = 1;

@@ -1075,7 +1092,7 @@ struct multipath *dm_get_multipath(const char *name)

 	if (!mpp->alias)

 		goto out;

-	if (dm_get_map(name, &mpp->size, NULL))

+	if (dm_get_map(name, &mpp->size, NULL) != DMP_OK)

 		goto out;

 	dm_get_uuid(name, mpp->wwid, WWID_SIZE);

@@ -1259,7 +1276,7 @@ do_foreach_partmaps (const char * mapname,

 		    /*

 		     * and we can fetch the map table from the kernel

 		     */

-		    !dm_get_map(names->name, &size, &params[0]) &&

+		    dm_get_map(names->name, &size, &params[0]) == DMP_OK &&

 		    /*

 		     * and the table maps over the multipath map

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

index 7557a86b..adb55000 100644

--- a/libmultipath/devmapper.h

+++ b/libmultipath/devmapper.h

@@ -27,6 +27,12 @@

 #define UUID_PREFIX "mpath-"

 #define UUID_PREFIX_LEN (sizeof(UUID_PREFIX) - 1)

+enum {

+	DMP_ERR,

+	DMP_OK,

+	DMP_NOT_FOUND,

+};

+

 void dm_init(int verbosity);

 void libmp_dm_init(void);

 void libmp_udev_set_sync_support(int on);

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

index 077f2e42..8137ea21 100644

--- a/libmultipath/structs_vec.c

+++ b/libmultipath/structs_vec.c

@@ -196,43 +196,47 @@ extract_hwe_from_path(struct multipath * mpp)

 int

 update_multipath_table (struct multipath *mpp, vector pathvec, int is_daemon)

 {

+	int r = DMP_ERR;

 	char params[PARAMS_SIZE] = {0};

 	if (!mpp)

-		return 1;

+		return r;

-	if (dm_get_map(mpp->alias, &mpp->size, params)) {

-		condlog(3, "%s: cannot get map", mpp->alias);

-		return 1;

+	r = dm_get_map(mpp->alias, &mpp->size, params);

+	if (r != DMP_OK) {

+		condlog(3, "%s: %s", mpp->alias, (r == DMP_ERR)? "error getting table" : "map not present");

+		return r;

 	}

 	if (disassemble_map(pathvec, params, mpp, is_daemon)) {

 		condlog(3, "%s: cannot disassemble map", mpp->alias);

-		return 1;

+		return DMP_ERR;

 	}

-	return 0;

+	return DMP_OK;

 }

 int

 update_multipath_status (struct multipath *mpp)

 {

+	int r = DMP_ERR;

 	char status[PARAMS_SIZE] = {0};

 	if (!mpp)

-		return 1;

+		return r;

-	if (dm_get_status(mpp->alias, status)) {

-		condlog(3, "%s: cannot get status", mpp->alias);

-		return 1;

+	r = dm_get_status(mpp->alias, status);

+	if (r != DMP_OK) {

+		condlog(3, "%s: %s", mpp->alias, (r == DMP_ERR)? "error getting status" : "map not present");

+		return r;

 	}

 	if (disassemble_status(status, mpp)) {

 		condlog(3, "%s: cannot disassemble status", mpp->alias);

-		return 1;

+		return DMP_ERR;

 	}

-	return 0;

+	return DMP_OK;

 }

 void sync_paths(struct multipath *mpp, vector pathvec)

@@ -264,10 +268,10 @@ int

 update_multipath_strings(struct multipath *mpp, vector pathvec, int is_daemon)

 {

 	struct pathgroup *pgp;

-	int i;

+	int i, r = DMP_ERR;

 	if (!mpp)

-		return 1;

+		return r;

 	update_mpp_paths(mpp, pathvec);

 	condlog(4, "%s: %s", mpp->alias, __FUNCTION__);

@@ -276,18 +280,21 @@ update_multipath_strings(struct multipath *mpp, vector pathvec, int is_daemon)

 	free_pgvec(mpp->pg, KEEP_PATHS);

 	mpp->pg = NULL;

-	if (update_multipath_table(mpp, pathvec, is_daemon))

-		return 1;

+	r = update_multipath_table(mpp, pathvec, is_daemon);

+	if (r != DMP_OK)

+		return r;

+

 	sync_paths(mpp, pathvec);

-	if (update_multipath_status(mpp))

-		return 1;

+	r = update_multipath_status(mpp);

+	if (r != DMP_OK)

+		return r;

 	vector_foreach_slot(mpp->pg, pgp, i)

 		if (pgp->paths)

 			path_group_prio_update(pgp);

-	return 0;

+	return DMP_OK;

 }

 static void enter_recovery_mode(struct multipath *mpp)

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

index 6b7db2c0..e3427d3d 100644

--- a/multipathd/main.c

+++ b/multipathd/main.c

@@ -414,7 +414,7 @@ int __setup_multipath(struct vectors *vecs, struct multipath *mpp,

 		goto out;

 	}

-	if (update_multipath_strings(mpp, vecs->pathvec, 1)) {

+	if (update_multipath_strings(mpp, vecs->pathvec, 1) != DMP_OK) {

 		condlog(0, "%s: failed to setup multipath", mpp->alias);

 		goto out;

 	}

@@ -553,9 +553,9 @@ add_map_without_path (struct vectors *vecs, const char *alias)

 	mpp->mpe = find_mpe(conf->mptable, mpp->wwid);

 	put_multipath_config(conf);

-	if (update_multipath_table(mpp, vecs->pathvec, 1))

+	if (update_multipath_table(mpp, vecs->pathvec, 1) != DMP_OK)

 		goto out;

-	if (update_multipath_status(mpp))

+	if (update_multipath_status(mpp) != DMP_OK)

 		goto out;

 	if (!vector_alloc_slot(vecs->mpvec))

@@ -1346,8 +1346,8 @@ map_discovery (struct vectors * vecs)

 		return 1;

 	vector_foreach_slot (vecs->mpvec, mpp, i)

-		if (update_multipath_table(mpp, vecs->pathvec, 1) ||

-		    update_multipath_status(mpp)) {

+		if (update_multipath_table(mpp, vecs->pathvec, 1) != DMP_OK ||

+		    update_multipath_status(mpp) != DMP_OK) {

 			remove_map(mpp, vecs, 1);

 			i--;

 		}

@@ -2087,7 +2087,7 @@ check_path (struct vectors * vecs, struct path * pp, unsigned int ticks)

 	/*

 	 * Synchronize with kernel state

 	 */

-	if (update_multipath_strings(pp->mpp, vecs->pathvec, 1)) {

+	if (update_multipath_strings(pp->mpp, vecs->pathvec, 1) != DMP_OK) {

 		condlog(1, "%s: Could not synchronize with kernel state",

 			pp->dev);

 		pp->dmstate = PSTATE_UNDEF;

-- 

2.17.2