From: Martin Wilck <[email protected]> "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 <[email protected]> --- 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 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
