gconcat: Add new lock to allow modifications to the disk list in preparation for online append
In addition, rename existing sc_lock to sc_append_lock Reviewed by: imp@ Pull Request: https://github.com/freebsd/freebsd-src/pull/447 Sponsored by: Netflix
This commit is contained in:
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e61e072f3b
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@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/module.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sx.h>
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#include <sys/bio.h>
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#include <sys/sbuf.h>
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#include <sys/sysctl.h>
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@ -105,6 +106,8 @@ g_concat_nvalid(struct g_concat_softc *sc)
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u_int no;
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struct g_concat_disk *disk;
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sx_assert(&sc->sc_disks_lock, SA_LOCKED);
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no = 0;
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TAILQ_FOREACH(disk, &sc->sc_disks, d_next) {
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if (disk->d_consumer != NULL)
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@ -173,10 +176,12 @@ g_concat_access(struct g_provider *pp, int dr, int dw, int de)
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struct g_consumer *cp1, *cp2, *tmp;
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struct g_concat_disk *disk;
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struct g_geom *gp;
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struct g_concat_softc *sc;
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int error;
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g_topology_assert();
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gp = pp->geom;
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sc = gp->softc;
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/* On first open, grab an extra "exclusive" bit */
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if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0)
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@ -185,6 +190,7 @@ g_concat_access(struct g_provider *pp, int dr, int dw, int de)
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if ((pp->acr + dr) == 0 && (pp->acw + dw) == 0 && (pp->ace + de) == 0)
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de--;
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sx_slock(&sc->sc_disks_lock);
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LIST_FOREACH_SAFE(cp1, &gp->consumer, consumer, tmp) {
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error = g_access(cp1, dr, dw, de);
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if (error != 0)
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@ -195,9 +201,11 @@ g_concat_access(struct g_provider *pp, int dr, int dw, int de)
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g_concat_remove_disk(disk); /* May destroy geom. */
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}
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}
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sx_sunlock(&sc->sc_disks_lock);
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return (0);
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fail:
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sx_sunlock(&sc->sc_disks_lock);
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LIST_FOREACH(cp2, &gp->consumer, consumer) {
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if (cp1 == cp2)
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break;
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@ -214,6 +222,7 @@ g_concat_candelete(struct bio *bp)
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int val;
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sc = bp->bio_to->geom->softc;
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sx_assert(&sc->sc_disks_lock, SX_LOCKED);
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TAILQ_FOREACH(disk, &sc->sc_disks, d_next) {
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if (!disk->d_removed && disk->d_candelete)
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break;
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@ -264,16 +273,16 @@ g_concat_done(struct bio *bp)
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pbp = bp->bio_parent;
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sc = pbp->bio_to->geom->softc;
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mtx_lock(&sc->sc_lock);
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mtx_lock(&sc->sc_completion_lock);
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if (pbp->bio_error == 0)
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pbp->bio_error = bp->bio_error;
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pbp->bio_completed += bp->bio_completed;
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pbp->bio_inbed++;
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if (pbp->bio_children == pbp->bio_inbed) {
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mtx_unlock(&sc->sc_lock);
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mtx_unlock(&sc->sc_completion_lock);
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g_io_deliver(pbp, pbp->bio_error);
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} else
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mtx_unlock(&sc->sc_lock);
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mtx_unlock(&sc->sc_completion_lock);
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g_destroy_bio(bp);
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}
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@ -288,6 +297,8 @@ g_concat_passdown(struct g_concat_softc *sc, struct bio *bp)
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struct bio *cbp;
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struct g_concat_disk *disk;
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sx_assert(&sc->sc_disks_lock, SX_LOCKED);
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bioq_init(&queue);
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TAILQ_FOREACH(disk, &sc->sc_disks, d_next) {
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cbp = g_clone_bio(bp);
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@ -334,6 +345,7 @@ g_concat_start(struct bio *bp)
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bp->bio_to->error, bp->bio_to->name));
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G_CONCAT_LOGREQ(bp, "Request received.");
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sx_slock(&sc->sc_disks_lock);
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switch (bp->bio_cmd) {
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case BIO_READ:
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@ -343,20 +355,20 @@ g_concat_start(struct bio *bp)
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case BIO_SPEEDUP:
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case BIO_FLUSH:
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g_concat_passdown(sc, bp);
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return;
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goto end;
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case BIO_GETATTR:
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if (strcmp("GEOM::kerneldump", bp->bio_attribute) == 0) {
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g_concat_kernel_dump(bp);
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return;
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goto end;
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} else if (strcmp("GEOM::candelete", bp->bio_attribute) == 0) {
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g_concat_candelete(bp);
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return;
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goto end;
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}
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/* To which provider it should be delivered? */
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/* FALLTHROUGH */
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default:
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g_io_deliver(bp, EOPNOTSUPP);
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return;
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goto end;
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}
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offset = bp->bio_offset;
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@ -386,7 +398,7 @@ g_concat_start(struct bio *bp)
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if (bp->bio_error == 0)
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bp->bio_error = ENOMEM;
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g_io_deliver(bp, bp->bio_error);
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return;
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goto end;
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}
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bioq_insert_tail(&queue, cbp);
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/*
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@ -422,6 +434,8 @@ g_concat_start(struct bio *bp)
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cbp->bio_caller1 = NULL;
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g_io_request(cbp, disk->d_consumer);
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}
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end:
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sx_sunlock(&sc->sc_disks_lock);
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}
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static void
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@ -522,17 +536,24 @@ g_concat_add_disk(struct g_concat_softc *sc, struct g_provider *pp, u_int no)
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int error;
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g_topology_assert();
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sx_slock(&sc->sc_disks_lock);
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/* Metadata corrupted? */
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if (no >= sc->sc_ndisks)
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if (no >= sc->sc_ndisks) {
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sx_sunlock(&sc->sc_disks_lock);
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return (EINVAL);
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}
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for (disk = TAILQ_FIRST(&sc->sc_disks); no > 0; no--) {
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disk = TAILQ_NEXT(disk, d_next);
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}
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/* Check if disk is not already attached. */
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if (disk->d_consumer != NULL)
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if (disk->d_consumer != NULL) {
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sx_sunlock(&sc->sc_disks_lock);
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return (EEXIST);
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}
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gp = sc->sc_geom;
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fcp = LIST_FIRST(&gp->consumer);
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@ -541,6 +562,7 @@ g_concat_add_disk(struct g_concat_softc *sc, struct g_provider *pp, u_int no)
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cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
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error = g_attach(cp, pp);
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if (error != 0) {
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sx_sunlock(&sc->sc_disks_lock);
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g_destroy_consumer(cp);
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return (error);
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}
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@ -548,6 +570,7 @@ g_concat_add_disk(struct g_concat_softc *sc, struct g_provider *pp, u_int no)
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if (fcp != NULL && (fcp->acr > 0 || fcp->acw > 0 || fcp->ace > 0)) {
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error = g_access(cp, fcp->acr, fcp->acw, fcp->ace);
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if (error != 0) {
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sx_sunlock(&sc->sc_disks_lock);
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g_detach(cp);
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g_destroy_consumer(cp);
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return (error);
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@ -556,8 +579,13 @@ g_concat_add_disk(struct g_concat_softc *sc, struct g_provider *pp, u_int no)
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if (sc->sc_type == G_CONCAT_TYPE_AUTOMATIC) {
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struct g_concat_metadata md;
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// temporarily give up the lock to avoid lock order violation
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// due to topology unlock in g_concat_read_metadata
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sx_sunlock(&sc->sc_disks_lock);
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/* Re-read metadata. */
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error = g_concat_read_metadata(cp, &md);
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sx_slock(&sc->sc_disks_lock);
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if (error != 0)
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goto fail;
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@ -579,9 +607,11 @@ g_concat_add_disk(struct g_concat_softc *sc, struct g_provider *pp, u_int no)
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G_CONCAT_DEBUG(0, "Disk %s attached to %s.", pp->name, sc->sc_name);
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g_concat_check_and_run(sc);
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sx_sunlock(&sc->sc_disks_lock); // need lock for check_and_run
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return (0);
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fail:
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sx_sunlock(&sc->sc_disks_lock);
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if (fcp != NULL && (fcp->acr > 0 || fcp->acw > 0 || fcp->ace > 0))
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g_access(cp, -fcp->acr, -fcp->acw, -fcp->ace);
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g_detach(cp);
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@ -630,7 +660,8 @@ g_concat_create(struct g_class *mp, const struct g_concat_metadata *md,
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TAILQ_INSERT_TAIL(&sc->sc_disks, disk, d_next);
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}
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sc->sc_type = type;
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mtx_init(&sc->sc_lock, "gconcat lock", NULL, MTX_DEF);
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mtx_init(&sc->sc_completion_lock, "gconcat lock", NULL, MTX_DEF);
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sx_init(&sc->sc_disks_lock, "gconcat append lock");
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gp->softc = sc;
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sc->sc_geom = gp;
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@ -683,7 +714,8 @@ g_concat_destroy(struct g_concat_softc *sc, boolean_t force)
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TAILQ_REMOVE(&sc->sc_disks, disk, d_next);
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free(disk, M_CONCAT);
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}
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mtx_destroy(&sc->sc_lock);
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mtx_destroy(&sc->sc_completion_lock);
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sx_destroy(&sc->sc_disks_lock);
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free(sc, M_CONCAT);
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G_CONCAT_DEBUG(0, "Device %s destroyed.", gp->name);
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@ -990,6 +1022,8 @@ g_concat_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
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sc = gp->softc;
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if (sc == NULL)
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return;
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sx_slock(&sc->sc_disks_lock);
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if (pp != NULL) {
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/* Nothing here. */
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} else if (cp != NULL) {
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@ -997,7 +1031,7 @@ g_concat_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
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disk = cp->private;
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if (disk == NULL)
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return;
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goto end;
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sbuf_printf(sb, "%s<End>%jd</End>\n", indent,
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(intmax_t)disk->d_end);
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sbuf_printf(sb, "%s<Start>%jd</Start>\n", indent,
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@ -1026,6 +1060,8 @@ g_concat_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
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sbuf_cat(sb, "DOWN");
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sbuf_cat(sb, "</State>\n");
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}
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end:
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sx_sunlock(&sc->sc_disks_lock);
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}
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DECLARE_GEOM_CLASS(g_concat_class, g_concat);
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@ -71,8 +71,10 @@ struct g_concat_softc {
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uint32_t sc_id; /* concat unique ID */
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uint16_t sc_ndisks;
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struct mtx sc_lock;
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TAILQ_HEAD(g_concat_disks, g_concat_disk) sc_disks;
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struct mtx sc_completion_lock; /* synchronizes cross-boundary IOs */
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struct sx sc_disks_lock; /* synchronizes modification of sc_disks */
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};
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#define sc_name sc_geom->name
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#endif /* _KERNEL */
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