Author: mav
Date: Fri Apr 5 10:29:14 2013
New Revision: 249146
URL: http://svnweb.freebsd.org/changeset/base/249146
Log:
MFC r227015:
Add mutex and two flags to make orphan() call properly asynchronous:
- delay consumer closing and detaching on orphan() until all I/Os complete;
- prevent new I/Os submission after orphan() called.
Previous implementation could destroy consumers still having active
requests and worked only because of global workaround made on GEOM level.
Modified:
stable/9/sys/geom/geom_vfs.c
Directory Properties:
stable/9/sys/ (props changed)
Modified: stable/9/sys/geom/geom_vfs.c
==============================================================================
--- stable/9/sys/geom/geom_vfs.c Fri Apr 5 10:27:05 2013
(r249145)
+++ stable/9/sys/geom/geom_vfs.c Fri Apr 5 10:29:14 2013
(r249146)
@@ -31,7 +31,9 @@ __FBSDID("$FreeBSD$");
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/kernel.h>
+#include <sys/lock.h>
#include <sys/malloc.h>
+#include <sys/mutex.h>
#include <sys/vnode.h>
#include <sys/mount.h> /* XXX Temporary for VFS_LOCK_GIANT */
@@ -45,6 +47,13 @@ __FBSDID("$FreeBSD$");
*/
#include <sys/buf.h>
+struct g_vfs_softc {
+ struct mtx sc_mtx;
+ struct bufobj *sc_bo;
+ int sc_active;
+ int sc_orphaned;
+};
+
static struct buf_ops __g_vfs_bufops = {
.bop_name = "GEOM_VFS",
.bop_write = bufwrite,
@@ -66,24 +75,32 @@ static struct g_class g_vfs_class = {
DECLARE_GEOM_CLASS(g_vfs_class, g_vfs);
static void
+g_vfs_destroy(void *arg, int flags __unused)
+{
+ struct g_consumer *cp;
+
+ g_topology_assert();
+ cp = arg;
+ if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
+ g_access(cp, -cp->acr, -cp->acw, -cp->ace);
+ g_detach(cp);
+ if (cp->geom->softc == NULL)
+ g_wither_geom(cp->geom, ENXIO);
+}
+
+static void
g_vfs_done(struct bio *bip)
{
+ struct g_consumer *cp;
+ struct g_vfs_softc *sc;
struct buf *bp;
- int vfslocked;
+ int vfslocked, destroy;
struct mount *mp;
struct vnode *vp;
struct cdev *cdevp;
- /*
- * Provider ('bio_to') could have withered away sometime
- * between incrementing the 'nend' in g_io_deliver() and now,
- * making 'bio_to' a dangling pointer. We cannot do that
- * in g_wither_geom(), as it would require going over
- * the 'g_bio_run_up' list, resetting the pointer.
- */
- if (bip->bio_from->provider == NULL)
- bip->bio_to = NULL;
-
+ cp = bip->bio_from;
+ sc = cp->geom->softc;
/*
* Collect statistics on synchronous and asynchronous read
* and write counts for disks that have associated filesystems.
@@ -134,6 +151,13 @@ g_vfs_done(struct bio *bip)
bp->b_ioflags |= BIO_ERROR;
bp->b_resid = bp->b_bcount - bip->bio_completed;
g_destroy_bio(bip);
+
+ mtx_lock(&sc->sc_mtx);
+ destroy = ((--sc->sc_active) == 0 && sc->sc_orphaned);
+ mtx_unlock(&sc->sc_mtx);
+ if (destroy)
+ g_post_event(g_vfs_destroy, cp, M_WAITOK, NULL);
+
vfslocked = VFS_LOCK_GIANT(((struct mount *)NULL));
bufdone(bp);
VFS_UNLOCK_GIANT(vfslocked);
@@ -142,17 +166,20 @@ g_vfs_done(struct bio *bip)
void
g_vfs_strategy(struct bufobj *bo, struct buf *bp)
{
+ struct g_vfs_softc *sc;
struct g_consumer *cp;
struct bio *bip;
int vfslocked;
cp = bo->bo_private;
- /* G_VALID_CONSUMER(cp); We likely lack topology lock */
+ sc = cp->geom->softc;
/*
* If the provider has orphaned us, just return EXIO.
*/
- if (cp->provider == NULL) {
+ mtx_lock(&sc->sc_mtx);
+ if (sc->sc_orphaned) {
+ mtx_unlock(&sc->sc_mtx);
bp->b_error = ENXIO;
bp->b_ioflags |= BIO_ERROR;
vfslocked = VFS_LOCK_GIANT(((struct mount *)NULL));
@@ -160,6 +187,8 @@ g_vfs_strategy(struct bufobj *bo, struct
VFS_UNLOCK_GIANT(vfslocked);
return;
}
+ sc->sc_active++;
+ mtx_unlock(&sc->sc_mtx);
bip = g_alloc_bio();
bip->bio_cmd = bp->b_iocmd;
@@ -179,14 +208,20 @@ static void
g_vfs_orphan(struct g_consumer *cp)
{
struct g_geom *gp;
+ struct g_vfs_softc *sc;
+ int destroy;
g_topology_assert();
gp = cp->geom;
+ sc = gp->softc;
g_trace(G_T_TOPOLOGY, "g_vfs_orphan(%p(%s))", cp, gp->name);
- if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
- g_access(cp, -cp->acr, -cp->acw, -cp->ace);
- g_detach(cp);
+ mtx_lock(&sc->sc_mtx);
+ sc->sc_orphaned = 1;
+ destroy = (sc->sc_active == 0);
+ mtx_unlock(&sc->sc_mtx);
+ if (destroy)
+ g_vfs_destroy(cp, 0);
/*
* Do not destroy the geom. Filesystem will do that during unmount.
@@ -199,6 +234,7 @@ g_vfs_open(struct vnode *vp, struct g_co
struct g_geom *gp;
struct g_provider *pp;
struct g_consumer *cp;
+ struct g_vfs_softc *sc;
struct bufobj *bo;
int vfslocked;
int error;
@@ -214,6 +250,10 @@ g_vfs_open(struct vnode *vp, struct g_co
if (pp == NULL)
return (ENOENT);
gp = g_new_geomf(&g_vfs_class, "%s.%s", fsname, pp->name);
+ sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
+ mtx_init(&sc->sc_mtx, "g_vfs", NULL, MTX_DEF);
+ sc->sc_bo = bo;
+ gp->softc = sc;
cp = g_new_consumer(gp);
g_attach(cp, pp);
error = g_access(cp, 1, wr, wr);
@@ -229,7 +269,6 @@ g_vfs_open(struct vnode *vp, struct g_co
bo->bo_ops = g_vfs_bufops;
bo->bo_private = cp;
bo->bo_bsize = pp->sectorsize;
- gp->softc = bo;
return (error);
}
@@ -238,13 +277,17 @@ void
g_vfs_close(struct g_consumer *cp)
{
struct g_geom *gp;
- struct bufobj *bo;
+ struct g_vfs_softc *sc;
g_topology_assert();
gp = cp->geom;
- bo = gp->softc;
- bufobj_invalbuf(bo, V_SAVE, 0, 0);
- bo->bo_private = cp->private;
- g_wither_geom_close(gp, ENXIO);
+ sc = gp->softc;
+ bufobj_invalbuf(sc->sc_bo, V_SAVE, 0, 0);
+ sc->sc_bo->bo_private = cp->private;
+ gp->softc = NULL;
+ mtx_destroy(&sc->sc_mtx);
+ if (!sc->sc_orphaned || cp->provider == NULL)
+ g_wither_geom_close(gp, ENXIO);
+ g_free(sc);
}
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