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Illumos 5812 - assertion failed in zrl_tryenter(): zr_owner==NULL
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5812 assertion failed in zrl_tryenter(): zr_owner==NULL
Reviewed by: George Wilson <[email protected]>
Reviewed by: Alex Reece <[email protected]>
Reviewed by: Will Andrews <[email protected]>
Approved by: Gordon Ross <[email protected]>

References:
  https://www.illumos.org/issues/5812
  illumos/illumos-gate@8df1730

Ported-by: DHE <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #3357
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ahrens authored and behlendorf committed Apr 30, 2015
1 parent 6186e29 commit 8dd86a1
Showing 1 changed file with 14 additions and 13 deletions.
27 changes: 14 additions & 13 deletions module/zfs/zrlock.c
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
*/
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2014 by Delphix. All rights reserved.
*/

/*
Expand All @@ -43,7 +44,7 @@
* A ZRL can be locked only while there are zero references, so ZRL_LOCKED is
* treated as zero references.
*/
#define ZRL_LOCKED ((uint32_t)-1)
#define ZRL_LOCKED -1
#define ZRL_DESTROYED -2

void
Expand All @@ -61,7 +62,7 @@ zrl_init(zrlock_t *zrl)
void
zrl_destroy(zrlock_t *zrl)
{
ASSERT(zrl->zr_refcount == 0);
ASSERT0(zrl->zr_refcount);

mutex_destroy(&zrl->zr_mtx);
zrl->zr_refcount = ZRL_DESTROYED;
Expand All @@ -81,7 +82,7 @@ zrl_add(zrlock_t *zrl)
uint32_t cas = atomic_cas_32(
(uint32_t *)&zrl->zr_refcount, n, n + 1);
if (cas == n) {
ASSERT((int32_t)n >= 0);
ASSERT3S((int32_t)n, >=, 0);
#ifdef ZFS_DEBUG
if (zrl->zr_owner == curthread) {
DTRACE_PROBE2(zrlock__reentry,
Expand All @@ -99,7 +100,7 @@ zrl_add(zrlock_t *zrl)
while (zrl->zr_refcount == ZRL_LOCKED) {
cv_wait(&zrl->zr_cv, &zrl->zr_mtx);
}
ASSERT(zrl->zr_refcount >= 0);
ASSERT3S(zrl->zr_refcount, >=, 0);
zrl->zr_refcount++;
#ifdef ZFS_DEBUG
zrl->zr_owner = curthread;
Expand All @@ -113,14 +114,14 @@ zrl_remove(zrlock_t *zrl)
{
uint32_t n;

n = atomic_dec_32_nv((uint32_t *)&zrl->zr_refcount);
ASSERT((int32_t)n >= 0);
#ifdef ZFS_DEBUG
if (zrl->zr_owner == curthread) {
zrl->zr_owner = NULL;
zrl->zr_caller = NULL;
}
#endif
n = atomic_dec_32_nv((uint32_t *)&zrl->zr_refcount);
ASSERT3S((int32_t)n, >=, 0);
}

int
Expand All @@ -133,26 +134,26 @@ zrl_tryenter(zrlock_t *zrl)
(uint32_t *)&zrl->zr_refcount, 0, ZRL_LOCKED);
if (cas == 0) {
#ifdef ZFS_DEBUG
ASSERT(zrl->zr_owner == NULL);
ASSERT3P(zrl->zr_owner, ==, NULL);
zrl->zr_owner = curthread;
#endif
return (1);
}
}

ASSERT((int32_t)n > ZRL_DESTROYED);
ASSERT3S((int32_t)n, >, ZRL_DESTROYED);

return (0);
}

void
zrl_exit(zrlock_t *zrl)
{
ASSERT(zrl->zr_refcount == ZRL_LOCKED);
ASSERT3S(zrl->zr_refcount, ==, ZRL_LOCKED);

mutex_enter(&zrl->zr_mtx);
#ifdef ZFS_DEBUG
ASSERT(zrl->zr_owner == curthread);
ASSERT3P(zrl->zr_owner, ==, curthread);
zrl->zr_owner = NULL;
membar_producer(); /* make sure the owner store happens first */
#endif
Expand All @@ -166,7 +167,7 @@ zrl_refcount(zrlock_t *zrl)
{
int n;

ASSERT(zrl->zr_refcount > ZRL_DESTROYED);
ASSERT3S(zrl->zr_refcount, >, ZRL_DESTROYED);

n = (int)zrl->zr_refcount;
return (n <= 0 ? 0 : n);
Expand All @@ -175,15 +176,15 @@ zrl_refcount(zrlock_t *zrl)
int
zrl_is_zero(zrlock_t *zrl)
{
ASSERT(zrl->zr_refcount > ZRL_DESTROYED);
ASSERT3S(zrl->zr_refcount, >, ZRL_DESTROYED);

return (zrl->zr_refcount <= 0);
}

int
zrl_is_locked(zrlock_t *zrl)
{
ASSERT(zrl->zr_refcount > ZRL_DESTROYED);
ASSERT3S(zrl->zr_refcount, >, ZRL_DESTROYED);

return (zrl->zr_refcount == ZRL_LOCKED);
}
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