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Properly handle races between open/close and orphan.
KASSERT the race between close and strategy, it is an error in the upper echelons if this happens, Add XXX: comment explaining why the ioctl/orphan race is not closed.
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parent
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commit
c7e1925c7c
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=112978
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@ -184,12 +184,11 @@ g_dev_open(dev_t dev, int flags, int fmt, struct thread *td)
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gp = dev->si_drv1;
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cp = dev->si_drv2;
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if (gp == NULL || cp == NULL)
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return(ENXIO);
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if (gp == NULL || cp == NULL || gp->softc != dev)
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return(ENXIO); /* g_dev_taste() not done yet */
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g_trace(G_T_ACCESS, "g_dev_open(%s, %d, %d, %p)",
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gp->name, flags, fmt, td);
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DROP_GIANT();
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g_topology_lock();
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r = flags & FREAD ? 1 : 0;
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w = flags & FWRITE ? 1 : 0;
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#ifdef notyet
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@ -197,11 +196,17 @@ g_dev_open(dev_t dev, int flags, int fmt, struct thread *td)
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#else
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e = 0;
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#endif
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error = g_access_rel(cp, r, w, e);
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DROP_GIANT();
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g_topology_lock();
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if (dev->si_devsw == NULL)
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error = ENXIO; /* We were orphaned */
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else
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error = g_access_rel(cp, r, w, e);
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g_topology_unlock();
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PICKUP_GIANT();
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g_waitidle();
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dev->si_bsize_phys = cp->provider->sectorsize;
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if (!error)
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dev->si_bsize_phys = cp->provider->sectorsize;
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return(error);
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}
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@ -218,8 +223,6 @@ g_dev_close(dev_t dev, int flags, int fmt, struct thread *td)
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return(ENXIO);
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g_trace(G_T_ACCESS, "g_dev_close(%s, %d, %d, %p)",
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gp->name, flags, fmt, td);
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DROP_GIANT();
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g_topology_lock();
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r = flags & FREAD ? -1 : 0;
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w = flags & FWRITE ? -1 : 0;
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#ifdef notyet
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@ -227,13 +230,26 @@ g_dev_close(dev_t dev, int flags, int fmt, struct thread *td)
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#else
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e = 0;
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#endif
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error = g_access_rel(cp, r, w, e);
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DROP_GIANT();
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g_topology_lock();
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if (dev->si_devsw == NULL)
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error = ENXIO; /* We were orphaned */
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else
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error = g_access_rel(cp, r, w, e);
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KASSERT((cp->acr || cp->acw) || (cp->nstart == cp->nend),
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("final g_dev_close() with outstanding bios"));
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g_topology_unlock();
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PICKUP_GIANT();
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g_waitidle();
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return (error);
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}
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/*
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* XXX: Until we have unmessed the ioctl situation, there is a race against
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* XXX: a concurrent orphanization. We cannot close it by holding topology
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* XXX: since that would prevent us from doing our job, and stalling events
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* XXX: will break (actually: stall) the BSD disklabel hacks.
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*/
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static int
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g_dev_ioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
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{
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@ -252,6 +268,8 @@ g_dev_ioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
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gio = NULL;
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error = 0;
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KASSERT(cp->acr || cp->acw,
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("Consumer with zero access count in g_dev_ioctl"));
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DROP_GIANT();
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gio = NULL;
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@ -377,6 +395,9 @@ g_dev_strategy(struct bio *bp)
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dev = bp->bio_dev;
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gp = dev->si_drv1;
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cp = dev->si_drv2;
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KASSERT(cp->acr || cp->acw,
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("Consumer with zero access count in g_dev_strategy"));
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bp2 = g_clone_bio(bp);
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KASSERT(bp2 != NULL, ("XXX: ENOMEM in a bad place"));
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bp2->bio_offset = (off_t)bp->bio_blkno << DEV_BSHIFT;
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@ -390,6 +411,9 @@ g_dev_strategy(struct bio *bp)
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bp, bp2, (intmax_t)bp->bio_offset, (intmax_t)bp2->bio_length,
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bp2->bio_data, bp2->bio_cmd);
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g_io_request(bp2, cp);
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KASSERT(cp->acr || cp->acw,
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("g_dev_strategy raced with g_dev_close and lost"));
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}
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/*
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@ -425,7 +449,7 @@ g_dev_orphan(struct g_consumer *cp)
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/* Wait for the cows to come home */
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while (cp->nstart != cp->nend)
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msleep(&dev, NULL, PRIBIO, "gdevorphan", 1);
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msleep(&dev, NULL, PRIBIO, "gdevorphan", hz / 10);
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if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
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g_access_rel(cp, -cp->acr, -cp->acw, -cp->ace);
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