---
sys/contrib/openzfs/module/zfs/zil.c | 34
+++++++++++++++++++++++++++-------
1 file changed, 27 insertions(+), 7 deletions(-)
diff --git a/sys/contrib/openzfs/module/zfs/zil.c
b/sys/contrib/openzfs/module/zfs/zil.c
index 00d66a2481d7..af7137faaccf 100644
--- a/sys/contrib/openzfs/module/zfs/zil.c
+++ b/sys/contrib/openzfs/module/zfs/zil.c
@@ -151,6 +151,7 @@ static kmem_cache_t *zil_lwb_cache;
static kmem_cache_t *zil_zcw_cache;
static void zil_lwb_commit(zilog_t *zilog, lwb_t *lwb, itx_t *itx);
+static void zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb);
static itx_t *zil_itx_clone(itx_t *oitx);
static int
@@ -1768,7 +1769,7 @@ static uint_t zil_maxblocksize =
SPA_OLD_MAXBLOCKSIZE;
* Has to be called under zl_issuer_lock to chain more lwbs.
*/
static lwb_t *
-zil_lwb_write_close(zilog_t *zilog, lwb_t *lwb)
+zil_lwb_write_close(zilog_t *zilog, lwb_t *lwb, list_t *ilwbs)
{
lwb_t *nlwb = NULL;
zil_chain_t *zilc;
@@ -1870,6 +1871,27 @@ zil_lwb_write_close(zilog_t *zilog, lwb_t *lwb)
dmu_tx_commit(tx);
+ /*
+ * We need to acquire the config lock for the lwb to issue it later.
+ * However, if we already have a queue of closed parent lwbs already
+ * holding the config lock (but not yet issued), we can't block here
+ * waiting on the lock or we will deadlock. In that case we must
+ * first issue to parent IOs before waiting on the lock.
+ */
+ if (ilwbs && !list_is_empty(ilwbs)) {
+ if (!spa_config_tryenter(spa, SCL_STATE, lwb, RW_READER)) {
+ lwb_t *tlwb;
+ while ((tlwb = list_remove_head(ilwbs)) != NULL)
+ zil_lwb_write_issue(zilog, tlwb);
+ spa_config_enter(spa, SCL_STATE, lwb, RW_READER);
+ }
+ } else {
+ spa_config_enter(spa, SCL_STATE, lwb, RW_READER);
+ }
+
+ if (ilwbs)
+ list_insert_tail(ilwbs, lwb);
+
/*
* If there was an allocation failure then nlwb will be null which
* forces a txg_wait_synced().
@@ -1933,7 +1955,7 @@ zil_lwb_write_issue(zilog_t *zilog, lwb_t *lwb)
ZIL_STAT_INCR(zilog, zil_itx_metaslab_normal_alloc,
BP_GET_LSIZE(&lwb->lwb_blk));
}
- spa_config_enter(zilog->zl_spa, SCL_STATE, lwb, RW_READER);
+ ASSERT(spa_config_held(zilog->zl_spa, SCL_STATE, RW_READER));
zil_lwb_add_block(lwb, &lwb->lwb_blk);
lwb->lwb_issued_timestamp = gethrtime();
zio_nowait(lwb->lwb_root_zio);
@@ -2037,8 +2059,7 @@ cont:
lwb_sp < zil_max_waste_space(zilog) &&
(dlen % max_log_data == 0 ||
lwb_sp < reclen + dlen % max_log_data))) {
- list_insert_tail(ilwbs, lwb);
- lwb = zil_lwb_write_close(zilog, lwb);
+ lwb = zil_lwb_write_close(zilog, lwb, ilwbs);
if (lwb == NULL)
return (NULL);
zil_lwb_write_open(zilog, lwb);
@@ -2937,8 +2958,7 @@ zil_process_commit_list(zilog_t *zilog,
zil_commit_waiter_t *zcw, list_t *ilwbs)
zfs_commit_timeout_pct / 100;
if (sleep < zil_min_commit_timeout ||
lwb->lwb_sz - lwb->lwb_nused < lwb->lwb_sz / 8) {
- list_insert_tail(ilwbs, lwb);
- lwb = zil_lwb_write_close(zilog, lwb);
+ lwb = zil_lwb_write_close(zilog, lwb, ilwbs);
zilog->zl_cur_used = 0;
if (lwb == NULL) {
while ((lwb = list_remove_head(ilwbs))
@@ -3096,7 +3116,7 @@ zil_commit_waiter_timeout(zilog_t *zilog,
zil_commit_waiter_t *zcw)
* since we've reached the commit waiter's timeout and it still
* hasn't been issued.
*/
- lwb_t *nlwb = zil_lwb_write_close(zilog, lwb);
+ lwb_t *nlwb = zil_lwb_write_close(zilog, lwb, NULL);
ASSERT3S(lwb->lwb_state, !=, LWB_STATE_OPENED);
