From: Martin Wilck <mwilck@xxxxxxx>
"force_reload" has originally been created to support multipath -r
(admin triggered reload). multipathd also uses this parameter
in DAEMON_CONFIGURE state, too. But this is causes unnecessary
device-mapper ioctls when multipathd is first started, if existing
maps have been discovered (perhaps set up by previous instance of
multipathd, e.g. in the initrd).
This patch introduces a weaker form of the force_reload parameter
to coalesce_paths(). The parameter can now take three values:
* FORCE_RELOAD_NONE: existing maps aren't touched at all
* FORCE_RELOAD_YES: all maps are rebuilt from scratch and (re)loaded in DM
* FORCE_RELOAD_WEAK: existing maps are compared to the current conf and only
reloaded in DM if there's a difference. This is useful during startup.
Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
---
libmultipath/config.h | 6 ++++++
libmultipath/configure.c | 16 ++++++++++++----
multipath/main.c | 2 +-
multipathd/cli_handlers.c | 3 ++-
multipathd/main.c | 12 ++++++++++--
5 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/libmultipath/config.h b/libmultipath/config.h
index 9a90745b..16f8b1cc 100644
--- a/libmultipath/config.h
+++ b/libmultipath/config.h
@@ -36,6 +36,12 @@ enum mpath_cmds {
CMD_ADD_WWID,
};
+enum force_reload_types {
+ FORCE_RELOAD_NONE,
+ FORCE_RELOAD_YES,
+ FORCE_RELOAD_WEAK,
+};
+
struct hwentry {
char * vendor;
char * product;
diff --git a/libmultipath/configure.c b/libmultipath/configure.c
index 5ad30074..f164801b 100644
--- a/libmultipath/configure.c
+++ b/libmultipath/configure.c
@@ -750,8 +750,15 @@ out:
return ret;
}
-int coalesce_paths(struct vectors *vecs, vector newmp, char *refwwid,
- int force_reload, enum mpath_cmds cmd)
+/*
+ * The force_reload parameter determines how coalesce_paths treats existing maps.
+ * FORCE_RELOAD_NONE: existing maps aren't touched at all
+ * FORCE_RELOAD_YES: all maps are rebuilt from scratch and (re)loaded in DM
+ * FORCE_RELOAD_WEAK: existing maps are compared to the current conf and only
+ * reloaded in DM if there's a difference. This is useful during startup.
+ */
+int coalesce_paths (struct vectors * vecs, vector newmp, char * refwwid,
+ int force_reload, enum mpath_cmds cmd)
{
int r = 1;
int k, i;
@@ -769,7 +776,7 @@ int coalesce_paths(struct vectors *vecs, vector newmp, char *refwwid,
if (refwwid && !strlen(refwwid))
refwwid = NULL;
- if (force_reload) {
+ if (force_reload != FORCE_RELOAD_NONE) {
vector_foreach_slot (pathvec, pp1, k) {
pp1->mpp = NULL;
}
@@ -858,7 +865,8 @@ int coalesce_paths(struct vectors *vecs, vector newmp, char *refwwid,
if (cmd == CMD_DRY_RUN)
mpp->action = ACT_DRY_RUN;
if (mpp->action == ACT_UNDEF)
- select_action(mpp, curmp, force_reload);
+ select_action(mpp, curmp,
+ force_reload == FORCE_RELOAD_YES ? 1 : 0);
r = domap(mpp, params, is_daemon);
diff --git a/multipath/main.c b/multipath/main.c
index ed57135a..4174d43d 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -578,7 +578,7 @@ main (int argc, char *argv[])
}
break;
case 'r':
- conf->force_reload = 1;
+ conf->force_reload = FORCE_RELOAD_YES;
break;
case 'i':
conf->ignore_wwids = 1;
diff --git a/multipathd/cli_handlers.c b/multipathd/cli_handlers.c
index b20b0546..c59e7fdc 100644
--- a/multipathd/cli_handlers.c
+++ b/multipathd/cli_handlers.c
@@ -778,7 +778,8 @@ cli_add_map (void * v, char ** reply, int * len, void * data)
rc = get_refwwid(CMD_NONE, param, DEV_DEVMAP,
vecs->pathvec, &refwwid);
if (refwwid) {
- if (coalesce_paths(vecs, NULL, refwwid, 0, 1))
+ if (coalesce_paths(vecs, NULL, refwwid,
+ FORCE_RELOAD_NONE, 1))
condlog(2, "%s: coalesce_paths failed",
param);
dm_lib_release();
diff --git a/multipathd/main.c b/multipathd/main.c
index 8f464bfb..e2e73749 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -535,7 +535,8 @@ ev_add_map (char * dev, char * alias, struct vectors * vecs)
r = get_refwwid(CMD_NONE, dev, DEV_DEVMAP, vecs->pathvec, &refwwid);
if (refwwid) {
- r = coalesce_paths(vecs, NULL, refwwid, 0, CMD_NONE);
+ r = coalesce_paths(vecs, NULL, refwwid, FORCE_RELOAD_NONE,
+ CMD_NONE);
dm_lib_release();
}
@@ -2039,6 +2040,7 @@ configure (struct vectors * vecs, int start_waiters)
vector mpvec;
int i, ret;
struct config *conf;
+ static int force_reload = FORCE_RELOAD_WEAK;
if (!vecs->pathvec && !(vecs->pathvec = vector_alloc())) {
condlog(0, "couldn't allocate path vec in configure");
@@ -2082,8 +2084,14 @@ configure (struct vectors * vecs, int start_waiters)
/*
* create new set of maps & push changed ones into dm
+ * In the first call, use FORCE_RELOAD_WEAK to avoid making
+ * superfluous ACT_RELOAD ioctls. Later calls are done
+ * with FORCE_RELOAD_YES.
*/
- if (coalesce_paths(vecs, mpvec, NULL, 1, CMD_NONE)) {
+ ret = coalesce_paths(vecs, mpvec, NULL, force_reload, CMD_NONE);
+ if (force_reload == FORCE_RELOAD_WEAK)
+ force_reload = FORCE_RELOAD_YES;
+ if (ret) {
condlog(0, "configure failed while coalescing paths");
return 1;
}
--
2.11.0
--
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