Date: Wed, 2 Dec 2009 19:32:31 +0100 From: Thomas Quinot <thomas@FreeBSD.ORG> To: freebsd-geom@freebsd.org Subject: Re: [PATCH] Forcing preferred path in geom_multipath Message-ID: <20091202183231.GA4362@melamine.cuivre.fr.eu.org> In-Reply-To: <20091202133911.GA96216@melamine.cuivre.fr.eu.org> References: <20091202133911.GA96216@melamine.cuivre.fr.eu.org>
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* Thomas Quinot, 2009-12-02 :
> Any suggestions as to how to achieve the desired ordering of preferred
> paths for each multipath geom?
OK, here's a simple solution, add a new verb to gmultipath to allow the
user to switch to a new preferred provider. Review/comments welcome.
Thomas.
Index: sbin/geom/class/multipath/geom_multipath.c
===================================================================
--- sbin/geom/class/multipath/geom_multipath.c (révision 200035)
+++ sbin/geom/class/multipath/geom_multipath.c (copie de travail)
@@ -48,6 +48,7 @@
static void mp_main(struct gctl_req *, unsigned int);
static void mp_label(struct gctl_req *);
static void mp_clear(struct gctl_req *);
+static void mp_prefer(struct gctl_req *);
struct g_command class_commands[] = {
{
@@ -58,6 +59,10 @@
"clear", G_FLAG_VERBOSE, mp_main, G_NULL_OPTS,
NULL, "[-v] prov ..."
},
+ {
+ "prefer", G_FLAG_VERBOSE, mp_main, G_NULL_OPTS,
+ NULL, "[-v] prov ..."
+ },
G_CMD_SENTINEL
};
@@ -75,6 +80,8 @@
mp_label(req);
} else if (strcmp(name, "clear") == 0) {
mp_clear(req);
+ } else if (strcmp(name, "prefer") == 0) {
+ mp_prefer(req);
} else {
gctl_error(req, "Unknown command: %s.", name);
}
@@ -228,3 +235,23 @@
}
}
}
+
+static void
+mp_prefer(struct gctl_req *req)
+{
+ const char *name, *comp, *errstr;
+ int nargs;
+
+ nargs = gctl_get_int(req, "nargs");
+ if (nargs != 2) {
+ gctl_error(req, "Usage: prefer GEOM PROVIDER");
+ return;
+ }
+ name = gctl_get_ascii(req, "arg0");
+ comp = gctl_get_ascii(req, "arg1");
+ errstr = gctl_issue (req);
+ if (errstr != NULL) {
+ fprintf(stderr, "Can't set %s preferred provider to %s: %s.\n",
+ name, comp, errstr);
+ }
+}
Index: sys/geom/geom_subr.c
===================================================================
--- sys/geom/geom_subr.c (révision 200035)
+++ sys/geom/geom_subr.c (copie de travail)
@@ -647,7 +647,7 @@
* can't risk that on the kernel stack.
*/
-static int
+int
redo_rank(struct g_geom *gp)
{
struct g_consumer *cp;
Index: sys/geom/multipath/g_multipath.c
===================================================================
--- sys/geom/multipath/g_multipath.c (révision 200035)
+++ sys/geom/multipath/g_multipath.c (copie de travail)
@@ -67,6 +67,8 @@
static void g_multipath_kt(void *);
static int g_multipath_destroy(struct g_geom *);
+static struct g_geom *
+g_multipath_find_geom(struct g_class *, const char *);
static int
g_multipath_destroy_geom(struct gctl_req *, struct g_class *, struct g_geom *);
@@ -706,6 +708,77 @@
}
}
+static void
+g_multipath_ctl_prefer(struct gctl_req *req, struct g_class *mp)
+{
+ struct g_geom *gp;
+ struct g_multipath_softc *sc;
+ struct g_consumer *cp;
+ struct g_provider *pp;
+ const char *name, *mpname;
+ static const char devpf[6] = "/dev/";
+ int *nargs;
+
+ g_topology_assert();
+
+ mpname = gctl_get_asciiparam(req, "arg0");
+ if (mpname == NULL) {
+ gctl_error(req, "No 'arg0' argument");
+ return;
+ }
+ gp = g_multipath_find_geom(mp, mpname);
+ if (gp == NULL) {
+ gctl_error(req, "Device %s is invalid", mpname);
+ return;
+ }
+ sc = gp->softc;
+
+ nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
+ if (nargs == NULL) {
+ gctl_error(req, "No 'nargs' argument");
+ return;
+ }
+ if (*nargs != 2) {
+ gctl_error(req, "missing device");
+ return;
+ }
+
+ name = gctl_get_asciiparam(req, "arg1");
+ if (name == NULL) {
+ gctl_error(req, "No 'arg1' argument");
+ return;
+ }
+ if (strncmp(name, devpf, 5) == 0) {
+ name += 5;
+ }
+ pp = g_provider_by_name(name);
+ if (pp == NULL) {
+ gctl_error(req, "Provider %s is invalid", name);
+ return;
+ }
+ g_topology_lock ();
+ LIST_FOREACH(cp, &gp->consumer, consumer) {
+ if (cp->provider == pp) {
+ /* Move cp to head of consumers list */
+ LIST_REMOVE(cp, consumers);
+ LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
+ redo_rank (cp->geom);
+
+ /* Make it the active path */
+ sc->cp_active = cp;
+ printf("GEOM_MULTIPATH: %s now active path in %s\n",
+ sc->cp_active->provider->name, sc->sc_name);
+ break;
+ }
+ }
+ g_topology_unlock ();
+ if (cp == NULL) {
+ gctl_error(req, "No consumer for %s", name);
+ return;
+ }
+
+}
+
static struct g_geom *
g_multipath_find_geom(struct g_class *mp, const char *name)
{
@@ -756,6 +829,8 @@
gctl_error(req, "Userland and kernel parts are out of sync");
} else if (strcmp(verb, "create") == 0) {
g_multipath_ctl_create(req, mp);
+ } else if (strcmp(verb, "prefer") == 0) {
+ g_multipath_ctl_prefer(req, mp);
} else if (strcmp(verb, "destroy") == 0) {
g_multipath_ctl_destroy(req, mp);
} else {
Index: sys/geom/geom.h
===================================================================
--- sys/geom/geom.h (révision 200035)
+++ sys/geom/geom.h (copie de travail)
@@ -276,6 +276,7 @@
#endif
int g_modevent(module_t, int, void *);
+int redo_rank(struct g_geom *gp);
/* geom_io.c */
struct bio * g_clone_bio(struct bio *);
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