Author: mav
Date: Sun Dec 29 17:10:21 2019
New Revision: 356178
URL: https://svnweb.freebsd.org/changeset/base/356178
Log:
Fix GEOM_MOUNTVER orphanization.
Previous code closed and detached 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.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
Modified:
head/sys/geom/mountver/g_mountver.c
Modified: head/sys/geom/mountver/g_mountver.c
==============================================================================
--- head/sys/geom/mountver/g_mountver.c Sun Dec 29 15:53:55 2019
(r356177)
+++ head/sys/geom/mountver/g_mountver.c Sun Dec 29 17:10:21 2019
(r356178)
@@ -85,14 +85,29 @@ struct g_class g_mountver_class = {
};
static void
+g_mountver_detach(void *arg, int flags __unused)
+{
+ struct g_consumer *cp = arg;
+
+ g_topology_assert();
+ if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
+ g_access(cp, -cp->acr, -cp->acw, -cp->ace);
+ g_detach(cp);
+}
+
+static void
g_mountver_done(struct bio *bp)
{
+ struct g_mountver_softc *sc;
struct g_geom *gp;
+ struct g_consumer *cp;
struct bio *pbp;
+ cp = bp->bio_from;
+ gp = cp->geom;
if (bp->bio_error != ENXIO) {
g_std_done(bp);
- return;
+ goto done;
}
/*
@@ -101,32 +116,45 @@ g_mountver_done(struct bio *bp)
* gets called. To work around that, we have to queue requests
* that failed with ENXIO, in order to send them later.
*/
- gp = bp->bio_from->geom;
-
pbp = bp->bio_parent;
KASSERT(pbp->bio_to == LIST_FIRST(&gp->provider),
("parent request was for someone else"));
g_destroy_bio(bp);
pbp->bio_inbed++;
g_mountver_queue(pbp);
+
+done:
+ sc = gp->softc;
+ mtx_lock(&sc->sc_mtx);
+ if (--cp->index == 0 && sc->sc_orphaned)
+ g_post_event(g_mountver_detach, cp, M_NOWAIT, NULL);
+ mtx_unlock(&sc->sc_mtx);
}
+/*
+ * Send the BIO down. The function is called with sc_mtx held to cover
+ * the race with orphan, but drops it before external calls.
+ */
static void
-g_mountver_send(struct bio *bp)
+g_mountver_send(struct g_geom *gp, struct bio *bp)
{
- struct g_geom *gp;
+ struct g_mountver_softc *sc = gp->softc;
+ struct g_consumer *cp;
struct bio *cbp;
- gp = bp->bio_to->geom;
-
+ mtx_assert(&sc->sc_mtx, MA_OWNED);
cbp = g_clone_bio(bp);
if (cbp == NULL) {
+ mtx_unlock(&sc->sc_mtx);
g_io_deliver(bp, ENOMEM);
return;
}
+ cp = LIST_FIRST(&gp->consumer);
+ cp->index++;
+ mtx_unlock(&sc->sc_mtx);
cbp->bio_done = g_mountver_done;
- g_io_request(cbp, LIST_FIRST(&gp->consumer));
+ g_io_request(cbp, cp);
}
static void
@@ -152,10 +180,12 @@ g_mountver_send_queued(struct g_geom *gp)
sc = gp->softc;
mtx_lock(&sc->sc_mtx);
- while ((bp = TAILQ_FIRST(&sc->sc_queue)) != NULL) {
+ while ((bp = TAILQ_FIRST(&sc->sc_queue)) != NULL && !sc->sc_orphaned) {
TAILQ_REMOVE(&sc->sc_queue, bp, bio_queue);
G_MOUNTVER_LOGREQ(bp, "Sending queued request.");
- g_mountver_send(bp);
+ /* sc_mtx is dropped inside */
+ g_mountver_send(gp, bp);
+ mtx_lock(&sc->sc_mtx);
}
mtx_unlock(&sc->sc_mtx);
}
@@ -171,8 +201,10 @@ g_mountver_discard_queued(struct g_geom *gp)
mtx_lock(&sc->sc_mtx);
while ((bp = TAILQ_FIRST(&sc->sc_queue)) != NULL) {
TAILQ_REMOVE(&sc->sc_queue, bp, bio_queue);
+ mtx_unlock(&sc->sc_mtx);
G_MOUNTVER_LOGREQ(bp, "Discarding queued request.");
g_io_deliver(bp, ENXIO);
+ mtx_lock(&sc->sc_mtx);
}
mtx_unlock(&sc->sc_mtx);
}
@@ -192,7 +224,9 @@ g_mountver_start(struct bio *bp)
* orphaning didn't happen yet. In that case, queue all subsequent
* requests in order to maintain ordering.
*/
+ mtx_lock(&sc->sc_mtx);
if (sc->sc_orphaned || !TAILQ_EMPTY(&sc->sc_queue)) {
+ mtx_unlock(&sc->sc_mtx);
if (sc->sc_shutting_down) {
G_MOUNTVER_LOGREQ(bp, "Discarding request due to
shutdown.");
g_io_deliver(bp, ENXIO);
@@ -204,7 +238,8 @@ g_mountver_start(struct bio *bp)
g_mountver_send_queued(gp);
} else {
G_MOUNTVER_LOGREQ(bp, "Sending request.");
- g_mountver_send(bp);
+ /* sc_mtx is dropped inside */
+ g_mountver_send(gp, bp);
}
}
@@ -466,14 +501,17 @@ static void
g_mountver_orphan(struct g_consumer *cp)
{
struct g_mountver_softc *sc;
+ int done;
g_topology_assert();
sc = cp->geom->softc;
+ mtx_lock(&sc->sc_mtx);
sc->sc_orphaned = 1;
- if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
- g_access(cp, -cp->acr, -cp->acw, -cp->ace);
- g_detach(cp);
+ done = (cp->index == 0);
+ mtx_unlock(&sc->sc_mtx);
+ if (done)
+ g_mountver_detach(cp, 0);
G_MOUNTVER_DEBUG(0, "%s is offline. Mount verification in progress.",
sc->sc_provider_name);
}
@@ -571,8 +609,8 @@ g_mountver_taste(struct g_class *mp, struct g_provider
return (NULL);
}
}
- g_mountver_send_queued(gp);
sc->sc_orphaned = 0;
+ g_mountver_send_queued(gp);
G_MOUNTVER_DEBUG(0, "%s has completed mount verification.",
sc->sc_provider_name);
return (gp);
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