Author: mav
Date: Fri Jan 10 00:43:40 2020
New Revision: 356580
URL: https://svnweb.freebsd.org/changeset/base/356580
Log:
MFC r356151: Fix GEOM_GATE orphanization.
Previous code closed and destroyed direct read consumer even with I/O still
in progress. This patch adds locking and request counting to postpone the
close till the last of running requests completes.
Modified:
stable/12/sys/geom/gate/g_gate.c
stable/12/sys/geom/gate/g_gate.h
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/geom/gate/g_gate.c
==============================================================================
--- stable/12/sys/geom/gate/g_gate.c Fri Jan 10 00:43:08 2020
(r356579)
+++ stable/12/sys/geom/gate/g_gate.c Fri Jan 10 00:43:40 2020
(r356580)
@@ -88,6 +88,19 @@ static struct g_gate_softc **g_gate_units;
static u_int g_gate_nunits;
static struct mtx g_gate_units_lock;
+static void
+g_gate_detach(void *arg, int flags __unused)
+{
+ struct g_consumer *cp = arg;
+
+ g_topology_assert();
+ G_GATE_DEBUG(1, "Destroying read consumer on provider %s orphan.",
+ cp->provider->name);
+ (void)g_access(cp, -1, 0, 0);
+ g_detach(cp);
+ g_destroy_consumer(cp);
+}
+
static int
g_gate_destroy(struct g_gate_softc *sc, boolean_t force)
{
@@ -139,6 +152,7 @@ g_gate_destroy(struct g_gate_softc *sc, boolean_t forc
g_gate_nunits--;
mtx_unlock(&g_gate_units_lock);
mtx_destroy(&sc->sc_queue_mtx);
+ mtx_destroy(&sc->sc_read_mtx);
g_topology_lock();
if ((cp = sc->sc_readcons) != NULL) {
sc->sc_readcons = NULL;
@@ -207,8 +221,11 @@ g_gate_queue_io(struct bio *bp)
static void
g_gate_done(struct bio *cbp)
{
+ struct g_gate_softc *sc;
struct bio *pbp;
+ struct g_consumer *cp;
+ cp = cbp->bio_from;
pbp = cbp->bio_parent;
if (cbp->bio_error == 0) {
pbp->bio_completed = cbp->bio_completed;
@@ -221,12 +238,20 @@ g_gate_done(struct bio *cbp)
pbp->bio_children--;
g_gate_queue_io(pbp);
}
+
+ sc = cp->geom->softc;
+ mtx_lock(&sc->sc_read_mtx);
+ if (--cp->index == 0 && sc->sc_readcons != cp)
+ g_post_event(g_gate_detach, cp, M_NOWAIT, NULL);
+ mtx_unlock(&sc->sc_read_mtx);
}
static void
g_gate_start(struct bio *pbp)
{
struct g_gate_softc *sc;
+ struct g_consumer *cp;
+ struct bio *cbp;
sc = pbp->bio_to->geom->softc;
if (sc == NULL || (sc->sc_flags & G_GATE_FLAG_DESTROY) != 0) {
@@ -236,21 +261,26 @@ g_gate_start(struct bio *pbp)
G_GATE_LOGREQ(2, pbp, "Request received.");
switch (pbp->bio_cmd) {
case BIO_READ:
- if (sc->sc_readcons != NULL) {
- struct bio *cbp;
-
- cbp = g_clone_bio(pbp);
- if (cbp == NULL) {
- g_io_deliver(pbp, ENOMEM);
- return;
- }
- cbp->bio_done = g_gate_done;
- cbp->bio_offset = pbp->bio_offset + sc->sc_readoffset;
- cbp->bio_to = sc->sc_readcons->provider;
- g_io_request(cbp, sc->sc_readcons);
+ if (sc->sc_readcons == NULL)
+ break;
+ cbp = g_clone_bio(pbp);
+ if (cbp == NULL) {
+ g_io_deliver(pbp, ENOMEM);
return;
}
- break;
+ mtx_lock(&sc->sc_read_mtx);
+ if ((cp = sc->sc_readcons) == NULL) {
+ mtx_unlock(&sc->sc_read_mtx);
+ g_destroy_bio(cbp);
+ pbp->bio_children--;
+ break;
+ }
+ cp->index++;
+ cbp->bio_offset = pbp->bio_offset + sc->sc_readoffset;
+ mtx_unlock(&sc->sc_read_mtx);
+ cbp->bio_done = g_gate_done;
+ g_io_request(cbp, cp);
+ return;
case BIO_DELETE:
case BIO_WRITE:
case BIO_FLUSH:
@@ -376,20 +406,18 @@ g_gate_orphan(struct g_consumer *cp)
{
struct g_gate_softc *sc;
struct g_geom *gp;
+ int done;
g_topology_assert();
gp = cp->geom;
sc = gp->softc;
- if (sc == NULL)
- return;
- KASSERT(cp == sc->sc_readcons, ("cp=%p sc_readcons=%p", cp,
- sc->sc_readcons));
- sc->sc_readcons = NULL;
- G_GATE_DEBUG(1, "Destroying read consumer on provider %s orphan.",
- cp->provider->name);
- (void)g_access(cp, -1, 0, 0);
- g_detach(cp);
- g_destroy_consumer(cp);
+ mtx_lock(&sc->sc_read_mtx);
+ if (sc->sc_readcons == cp)
+ sc->sc_readcons = NULL;
+ done = (cp->index == 0);
+ mtx_unlock(&sc->sc_read_mtx);
+ if (done)
+ g_gate_detach(cp, 0);
}
static void
@@ -482,6 +510,7 @@ g_gate_create(struct g_gate_ctl_create *ggio)
bioq_init(&sc->sc_inqueue);
bioq_init(&sc->sc_outqueue);
mtx_init(&sc->sc_queue_mtx, "gg:queue", NULL, MTX_DEF);
+ mtx_init(&sc->sc_read_mtx, "gg:read", NULL, MTX_DEF);
sc->sc_queue_count = 0;
sc->sc_queue_size = ggio->gctl_maxcount;
if (sc->sc_queue_size > G_GATE_MAX_QUEUE_SIZE)
@@ -595,6 +624,7 @@ fail2:
fail1:
mtx_unlock(&g_gate_units_lock);
mtx_destroy(&sc->sc_queue_mtx);
+ mtx_destroy(&sc->sc_read_mtx);
free(sc, M_GATE);
return (error);
}
@@ -604,7 +634,7 @@ g_gate_modify(struct g_gate_softc *sc, struct g_gate_c
{
struct g_provider *pp;
struct g_consumer *cp;
- int error;
+ int done, error;
if ((ggio->gctl_modify & GG_MODIFY_MEDIASIZE) != 0) {
if (ggio->gctl_mediasize <= 0) {
@@ -627,13 +657,15 @@ g_gate_modify(struct g_gate_softc *sc, struct g_gate_c
if ((ggio->gctl_modify & GG_MODIFY_READPROV) != 0) {
g_topology_lock();
- if (sc->sc_readcons != NULL) {
- cp = sc->sc_readcons;
+ mtx_lock(&sc->sc_read_mtx);
+ if ((cp = sc->sc_readcons) != NULL) {
sc->sc_readcons = NULL;
- (void)g_access(cp, -1, 0, 0);
- g_detach(cp);
- g_destroy_consumer(cp);
- }
+ done = (cp->index == 0);
+ mtx_unlock(&sc->sc_read_mtx);
+ if (done)
+ g_gate_detach(cp, 0);
+ } else
+ mtx_unlock(&sc->sc_read_mtx);
if (ggio->gctl_readprov[0] != '\0') {
pp = g_provider_by_name(ggio->gctl_readprov);
if (pp == NULL) {
Modified: stable/12/sys/geom/gate/g_gate.h
==============================================================================
--- stable/12/sys/geom/gate/g_gate.h Fri Jan 10 00:43:08 2020
(r356579)
+++ stable/12/sys/geom/gate/g_gate.h Fri Jan 10 00:43:40 2020
(r356580)
@@ -91,16 +91,15 @@ struct g_gate_softc {
uint32_t sc_queue_count; /* P: sc_queue_mtx */
uint32_t sc_queue_size; /* P: (read-only) */
u_int sc_timeout; /* P: (read-only) */
- struct g_consumer *sc_readcons; /* P: XXX */
- off_t sc_readoffset; /* P: XXX */
+ struct g_consumer *sc_readcons; /* P: sc_read_mtx */
+ off_t sc_readoffset; /* P: sc_read_mtx */
struct callout sc_callout; /* P: (modified only
from callout
thread) */
- uintptr_t sc_seq; /* P: (modified only
- from g_down
- thread) */
+ uintptr_t sc_seq; /* P: sc_queue_mtx */
LIST_ENTRY(g_gate_softc) sc_next; /* P: g_gate_list_mtx */
char sc_info[G_GATE_INFOSIZE]; /* P: (read-only) */
+ struct mtx sc_read_mtx;
};
#define G_GATE_DEBUG(lvl, ...) do {
\
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