The branch main has been updated by mm: URL: https://cgit.FreeBSD.org/src/commit/?id=cd25b0f740f8c846562fd66e7380437eb898c875
commit cd25b0f740f8c846562fd66e7380437eb898c875 Author: Martin Matuska <[email protected]> AuthorDate: 2023-08-10 07:55:42 +0000 Commit: Martin Matuska <[email protected]> CommitDate: 2023-08-10 07:56:53 +0000 zfs: cherry-pick fix from openzfs Vendor PR: #15080 ZIL: Fix config lock deadlock Obtained from: OpenZFS OpenZFS commit: 2cb992a99ccadb78d97049b40bd442eb4fdc549d Note: full vendor imports will continue when stable/14 has been branched --- 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);
