From c6e58a8d173b7e9689952d07678ba79702ba8021 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marko=20M=C3=A4kel=C3=A4?= Date: Fri, 21 Apr 2023 11:05:44 +0300 Subject: [PATCH] MDEV-30753 fixup: Unsafe buffer page restoration trx_purge_free_segment(): The buffer-fix only prevents a block from being freed completely from the buffer pool, but it will not prevent the block from being evicted. Recheck the page identifier after acquiring an exclusive page latch. If it has changed, backtrack and invoke buf_page_get_gen() to look up the page normally. --- storage/innobase/trx/trx0purge.cc | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/storage/innobase/trx/trx0purge.cc b/storage/innobase/trx/trx0purge.cc index 38438108480..b22a85f4646 100644 --- a/storage/innobase/trx/trx0purge.cc +++ b/storage/innobase/trx/trx0purge.cc @@ -367,19 +367,30 @@ void trx_purge_free_segment(mtr_t &mtr, trx_rseg_t* rseg, fil_addr_t hdr_addr) block->frame, &mtr)) { block->fix(); + const page_id_t id{block->page.id()}; mtr.commit(); /* NOTE: If the server is killed after the log that was produced up to this point was written, and before the log from the mtr.commit() in our caller is written, then the pages belonging to the undo log will become unaccessible garbage. - This does not matters when using multiple innodb_undo_tablespaces; + This does not matter when using multiple innodb_undo_tablespaces; innodb_undo_log_truncate=ON will be able to reclaim the space. */ log_free_check(); mtr.start(); ut_ad(rw_lock_s_lock_nowait(block->debug_latch, __FILE__, __LINE__)); rw_lock_x_lock(&block->lock); - mtr_memo_push(&mtr, block, MTR_MEMO_PAGE_X_FIX); + if (UNIV_UNLIKELY(block->page.id() != id)) + { + block->unfix(); + rw_lock_x_unlock(&block->lock); + ut_d(rw_lock_s_unlock(block->debug_latch)); + block= buf_page_get(id, 0, RW_X_LATCH, &mtr); + if (!block) + return; + } + else + mtr_memo_push(&mtr, block, MTR_MEMO_PAGE_X_FIX); } while (!fseg_free_step(TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER +