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Prevent g_access calls to bad multipath members

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When a multipath member is orphaned its access members are zeroed before its
removed if marked for wither, so prevent any future calls to g_access on
such members.

This prevents a panic on debug kernels which validates the resultant values
aren't negative.

Reviewed by:	mav
MFC after:	2 weeks
Sponsored by:	Multiplay
Differential Revision:	https://reviews.freebsd.org/D4416
This commit is contained in:
Steven Hartland 2015-12-15 21:11:41 +00:00
parent c7006ec555
commit 25080ac4d4
1 changed files with 18 additions and 2 deletions
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20
sys/geom/multipath/g_multipath.c
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@ -107,8 +107,9 @@ struct g_class g_multipath_class = {
#define MP_NEW 0x00000004
#define MP_POSTED 0x00000008
#define MP_BAD (MP_FAIL | MP_LOST | MP_NEW)
#define MP_IDLE 0x00000010
#define MP_IDLE_MASK 0xfffffff0
#define MP_WITHER 0x00000010
#define MP_IDLE 0x00000020
#define MP_IDLE_MASK 0xffffffe0
static int
g_multipath_good(struct g_geom *gp)
@ -204,6 +205,7 @@ g_mpd(void *arg, int flags __unused)
g_access(cp, -cp->acr, -cp->acw, -cp->ace);
if (w > 0 && cp->provider != NULL &&
(cp->provider->geom->flags & G_GEOM_WITHER) == 0) {
cp->index |= MP_WITHER;
g_post_event(g_mpd, cp, M_WAITOK, NULL);
return;
}
@ -467,23 +469,37 @@ g_multipath_access(struct g_provider *pp, int dr, int dw, int de)
gp = pp->geom;
/* Error used if we have no valid consumers. */
error = ENXIO;
LIST_FOREACH(cp, &gp->consumer, consumer) {
if (cp->index & MP_WITHER)
continue;
error = g_access(cp, dr, dw, de);
if (error) {
badcp = cp;
goto fail;
}
}
if (error != 0)
return (error);
sc = gp->softc;
sc->sc_opened += dr + dw + de;
if (sc->sc_stopping && sc->sc_opened == 0)
g_multipath_destroy(gp);
return (0);
fail:
LIST_FOREACH(cp, &gp->consumer, consumer) {
if (cp == badcp)
break;
if (cp->index & MP_WITHER)
continue;
(void) g_access(cp, -dr, -dw, -de);
}
return (error);