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gconcat: Add new lock to allow modifications to the disk list in preparation for online append

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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:
Noah Bergbauer 2020-12-27 22:04:45 +01:00 committed by Warner Losh
parent e61e072f3b
commit 56fd97660a
2 changed files with 52 additions and 14 deletions
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62
sys/geom/concat/g_concat.c
View File

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

4
sys/geom/concat/g_concat.h
View File

@ -71,8 +71,10 @@ struct g_concat_softc {
uint32_t sc_id; /* concat unique ID */
uint16_t sc_ndisks;
struct mtx sc_lock;
TAILQ_HEAD(g_concat_disks, g_concat_disk) sc_disks;
struct mtx sc_completion_lock; /* synchronizes cross-boundary IOs */
struct sx sc_disks_lock; /* synchronizes modification of sc_disks */
};
#define sc_name sc_geom->name
#endif /* _KERNEL */