e8827f4094
On the 0 -> 1 transition of sc_enxio_active, report that we're doing
this. This is a rare, but interesting, event. Convert to using atomics
to set this field to prevent a rare race:
In CAM, when we invalidate a device, one thread (T1) will start the
process in error processing called from *dadone
(cam_periph_error). This routine will queue work to xpt_async_td
(T2) and indicate to *dadone to call biodone(ENXIO) for the bio. T2
wakes up and basically waits to acquire the periph lock. T2 will do
so when T1 drops the periph lock just before T1's call to
biodone. T2 acquires the lock and calls biodone(ENXIO) on all
pending bios. These two threads will race and we could lose the
printf or get two in rare cases. Since we only touch sc_enxio_active
in an error path that's infrequent, the extra atomic traffic will be
rare but will ensure robustness.
Sponsored by: Netflix
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D35037
322 lines
7.7 KiB
C
322 lines
7.7 KiB
C
/*-
|
|
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
|
|
*
|
|
* Copyright (c) 2004 Poul-Henning Kamp
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#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/sbuf.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/mount.h>
|
|
|
|
#include <geom/geom.h>
|
|
#include <geom/geom_vfs.h>
|
|
|
|
/*
|
|
* subroutines for use by filesystems.
|
|
*
|
|
* XXX: should maybe live somewhere else ?
|
|
*/
|
|
#include <sys/buf.h>
|
|
|
|
struct g_vfs_softc {
|
|
struct mtx sc_mtx;
|
|
struct bufobj *sc_bo;
|
|
struct g_event *sc_event;
|
|
int sc_active;
|
|
bool sc_orphaned;
|
|
int sc_enxio_active;
|
|
};
|
|
|
|
static struct buf_ops __g_vfs_bufops = {
|
|
.bop_name = "GEOM_VFS",
|
|
.bop_write = bufwrite,
|
|
.bop_strategy = g_vfs_strategy,
|
|
.bop_sync = bufsync,
|
|
.bop_bdflush = bufbdflush
|
|
};
|
|
|
|
struct buf_ops *g_vfs_bufops = &__g_vfs_bufops;
|
|
|
|
static g_orphan_t g_vfs_orphan;
|
|
|
|
static struct g_class g_vfs_class = {
|
|
.name = "VFS",
|
|
.version = G_VERSION,
|
|
.orphan = g_vfs_orphan,
|
|
};
|
|
|
|
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_event *event;
|
|
struct g_vfs_softc *sc;
|
|
struct buf *bp;
|
|
int destroy;
|
|
struct mount *mp;
|
|
struct vnode *vp;
|
|
struct cdev *cdevp;
|
|
|
|
/*
|
|
* Collect statistics on synchronous and asynchronous read
|
|
* and write counts for disks that have associated filesystems.
|
|
*/
|
|
bp = bip->bio_caller2;
|
|
vp = bp->b_vp;
|
|
if (vp != NULL) {
|
|
/*
|
|
* If not a disk vnode, use its associated mount point
|
|
* otherwise use the mountpoint associated with the disk.
|
|
*/
|
|
VI_LOCK(vp);
|
|
if (vp->v_type != VCHR ||
|
|
(cdevp = vp->v_rdev) == NULL ||
|
|
cdevp->si_devsw == NULL ||
|
|
(cdevp->si_devsw->d_flags & D_DISK) == 0)
|
|
mp = vp->v_mount;
|
|
else
|
|
mp = cdevp->si_mountpt;
|
|
if (mp != NULL) {
|
|
if (bp->b_iocmd == BIO_READ) {
|
|
if (LK_HOLDER(bp->b_lock.lk_lock) == LK_KERNPROC)
|
|
mp->mnt_stat.f_asyncreads++;
|
|
else
|
|
mp->mnt_stat.f_syncreads++;
|
|
} else if (bp->b_iocmd == BIO_WRITE) {
|
|
if (LK_HOLDER(bp->b_lock.lk_lock) == LK_KERNPROC)
|
|
mp->mnt_stat.f_asyncwrites++;
|
|
else
|
|
mp->mnt_stat.f_syncwrites++;
|
|
}
|
|
}
|
|
VI_UNLOCK(vp);
|
|
}
|
|
|
|
cp = bip->bio_from;
|
|
sc = cp->geom->softc;
|
|
if (bip->bio_error != 0 && bip->bio_error != EOPNOTSUPP) {
|
|
if ((bp->b_xflags & BX_CVTENXIO) != 0) {
|
|
if (atomic_cmpset_int(&sc->sc_enxio_active, 0, 1))
|
|
printf("g_vfs_done(): %s converting all errors to ENXIO\n",
|
|
bip->bio_to->name);
|
|
}
|
|
if (sc->sc_enxio_active)
|
|
bip->bio_error = ENXIO;
|
|
g_print_bio("g_vfs_done():", bip, "error = %d",
|
|
bip->bio_error);
|
|
}
|
|
bp->b_error = bip->bio_error;
|
|
bp->b_ioflags = bip->bio_flags;
|
|
if (bip->bio_error)
|
|
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);
|
|
if (destroy) {
|
|
event = sc->sc_event;
|
|
sc->sc_event = NULL;
|
|
} else
|
|
event = NULL;
|
|
mtx_unlock(&sc->sc_mtx);
|
|
if (destroy)
|
|
g_post_event_ep(g_vfs_destroy, cp, event, NULL);
|
|
|
|
bufdone(bp);
|
|
}
|
|
|
|
void
|
|
g_vfs_strategy(struct bufobj *bo, struct buf *bp)
|
|
{
|
|
struct g_vfs_softc *sc;
|
|
struct g_consumer *cp;
|
|
struct bio *bip;
|
|
|
|
cp = bo->bo_private;
|
|
sc = cp->geom->softc;
|
|
|
|
/*
|
|
* If the provider has orphaned us, just return ENXIO.
|
|
*/
|
|
mtx_lock(&sc->sc_mtx);
|
|
if (sc->sc_orphaned || sc->sc_enxio_active) {
|
|
mtx_unlock(&sc->sc_mtx);
|
|
bp->b_error = ENXIO;
|
|
bp->b_ioflags |= BIO_ERROR;
|
|
bufdone(bp);
|
|
return;
|
|
}
|
|
sc->sc_active++;
|
|
mtx_unlock(&sc->sc_mtx);
|
|
|
|
bip = g_alloc_bio();
|
|
bip->bio_cmd = bp->b_iocmd;
|
|
bip->bio_offset = bp->b_iooffset;
|
|
bip->bio_length = bp->b_bcount;
|
|
bdata2bio(bp, bip);
|
|
if ((bp->b_flags & B_BARRIER) != 0) {
|
|
bip->bio_flags |= BIO_ORDERED;
|
|
bp->b_flags &= ~B_BARRIER;
|
|
}
|
|
if (bp->b_iocmd == BIO_SPEEDUP)
|
|
bip->bio_flags |= bp->b_ioflags;
|
|
bip->bio_done = g_vfs_done;
|
|
bip->bio_caller2 = bp;
|
|
#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
|
|
buf_track(bp, __func__);
|
|
bip->bio_track_bp = bp;
|
|
#endif
|
|
g_io_request(bip, cp);
|
|
}
|
|
|
|
static void
|
|
g_vfs_orphan(struct g_consumer *cp)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_event *event;
|
|
struct g_vfs_softc *sc;
|
|
int destroy;
|
|
|
|
g_topology_assert();
|
|
|
|
gp = cp->geom;
|
|
g_trace(G_T_TOPOLOGY, "g_vfs_orphan(%p(%s))", cp, gp->name);
|
|
sc = gp->softc;
|
|
if (sc == NULL)
|
|
return;
|
|
event = g_alloc_event(M_WAITOK);
|
|
mtx_lock(&sc->sc_mtx);
|
|
KASSERT(sc->sc_event == NULL, ("g_vfs %p already has an event", sc));
|
|
sc->sc_orphaned = true;
|
|
destroy = (sc->sc_active == 0);
|
|
if (!destroy) {
|
|
sc->sc_event = event;
|
|
event = NULL;
|
|
}
|
|
mtx_unlock(&sc->sc_mtx);
|
|
if (destroy) {
|
|
g_free(event);
|
|
g_vfs_destroy(cp, 0);
|
|
}
|
|
|
|
/*
|
|
* Do not destroy the geom. Filesystem will do that during unmount.
|
|
*/
|
|
}
|
|
|
|
int
|
|
g_vfs_open(struct vnode *vp, struct g_consumer **cpp, const char *fsname, int wr)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_provider *pp;
|
|
struct g_consumer *cp;
|
|
struct g_vfs_softc *sc;
|
|
struct bufobj *bo;
|
|
int error;
|
|
|
|
g_topology_assert();
|
|
|
|
*cpp = NULL;
|
|
bo = &vp->v_bufobj;
|
|
if (bo->bo_private != vp)
|
|
return (EBUSY);
|
|
|
|
pp = g_dev_getprovider(vp->v_rdev);
|
|
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);
|
|
error = g_attach(cp, pp);
|
|
if (error) {
|
|
g_wither_geom(gp, ENXIO);
|
|
return (error);
|
|
}
|
|
error = g_access(cp, 1, wr, wr);
|
|
if (error) {
|
|
g_wither_geom(gp, ENXIO);
|
|
return (error);
|
|
}
|
|
vnode_create_vobject(vp, pp->mediasize, curthread);
|
|
*cpp = cp;
|
|
cp->private = vp;
|
|
cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
|
|
bo->bo_ops = g_vfs_bufops;
|
|
bo->bo_private = cp;
|
|
bo->bo_bsize = pp->sectorsize;
|
|
|
|
return (error);
|
|
}
|
|
|
|
void
|
|
g_vfs_close(struct g_consumer *cp)
|
|
{
|
|
struct g_geom *gp;
|
|
struct g_vfs_softc *sc;
|
|
|
|
g_topology_assert();
|
|
|
|
gp = cp->geom;
|
|
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);
|
|
KASSERT(sc->sc_event == NULL, ("g_vfs %p event is non-NULL", sc));
|
|
g_free(sc);
|
|
}
|