MDEV-15528 Punch holes when pages are freed

- Addressed marko's review comments.

6 files changed, 91 insertions, 37 deletions

diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc
index c4a9b1a8176..984b9982324 100644
--- a/storage/innobase/buf/buf0buf.cc
+++ b/storage/innobase/buf/buf0buf.cc
@@ -4507,6 +4507,63 @@ buf_page_try_get_func(
 	return(block);
 }
 
+/** Mark the page status as FREED for the given tablespace id and
+page number. If the page is not in the buffer pool then ignore it.
+@param[in]	page_id	page id
+@param[in,out]	mtr	mini-transaction
+@param[in]	file	file name
+@param[in]	line	line where called */
+void buf_page_free(
+	const page_id_t page_id,
+	mtr_t*		mtr,
+	const char*	file,
+	unsigned 	line)
+{
+	buf_block_t*	block;
+	rw_lock_t*	hash_lock;
+
+	ut_ad(mtr);
+	ut_ad(mtr->is_active());
+
+	buf_pool->stat.n_page_gets++;
+	hash_lock = buf_page_hash_lock_get(page_id);
+	rw_lock_s_lock(hash_lock);
+
+	/* page_hash can be changed. */
+	hash_lock = buf_page_hash_lock_s_confirm(hash_lock, page_id);
+
+	block = (buf_block_t*) buf_page_hash_get_low(page_id);
+
+	if (!block) {
+		/* Page is not in buffer pool */
+		rw_lock_s_unlock(hash_lock);
+		return;
+	}
+	block->fix();
+
+	/* Now safe to release page_hash mutex */
+	rw_lock_s_unlock(hash_lock);
+
+	ut_ad(block->page.buf_fix_count > 0);
+
+#ifdef UNIV_DEBUG
+	if (!fsp_is_system_temporary(page_id.space())) {
+		ibool   ret;
+		ret = rw_lock_s_lock_nowait(
+			block->debug_latch, file, line);
+		ut_a(ret);
+	}
+#endif /* UNIV_DEBUG */
+
+	mtr_memo_type_t	fix_type = MTR_MEMO_PAGE_X_FIX;
+	rw_lock_x_lock_inline(&block->lock, 0, file, line);
+	mtr_memo_push(mtr, block, fix_type);
+
+	block->page.status = FREED;
+	buf_block_dbg_add_level(block, SYNC_NO_ORDER_CHECK);
+	buf_pool->stat.n_page_gets++;
+}
+
 /********************************************************************//**
 Initialize some fields of a control block. */
 UNIV_INLINE
diff --git a/storage/innobase/buf/buf0flu.cc b/storage/innobase/buf/buf0flu.cc
index 8c929c44a94..07e60eee5d1 100644
--- a/storage/innobase/buf/buf0flu.cc
+++ b/storage/innobase/buf/buf0flu.cc
@@ -1117,7 +1117,7 @@ buf_flush_write_block_low(
 
 	if (bpage->status == FREED) {
 		/** Zero out the page if the page is freed */
-		memset(frame, 0, bpage->physical_size());
+		frame = const_cast<byte*>(field_ref_zero);
 	}
 
 	const bool use_doublewrite = (bpage->status == NORMAL)
@@ -1203,6 +1203,7 @@ bool buf_flush_page(buf_page_t* bpage, buf_flush_t flush_type, bool sync)
 	shutting down */
 	if (!srv_undo_sources
 	    && fsp_is_system_temporary(bpage->id.space())) {
+remove_flush:
 		buf_flush_remove(bpage);
 		return false;
 	}
@@ -1210,13 +1211,12 @@ bool buf_flush_page(buf_page_t* bpage, buf_flush_t flush_type, bool sync)
 	/* Ignore the flushing of freed page */
 	if (bpage->status == FREED) {
 		if (!srv_immediate_scrub_data_uncompressed) {
-			buf_flush_remove(bpage);
-			return false;
+			goto remove_flush;
 		}
 	}
 
-	bool	is_uncompressed = (buf_page_get_state(bpage)
-				   == BUF_BLOCK_FILE_PAGE);
+	const bool is_uncompressed = (buf_page_get_state(bpage)
+				      == BUF_BLOCK_FILE_PAGE);
 
 	ut_ad(is_uncompressed == (block_mutex != &buf_pool->zip_mutex));
 
diff --git a/storage/innobase/fsp/fsp0fsp.cc b/storage/innobase/fsp/fsp0fsp.cc
index bcf76cc1f84..5b0cc94cbb4 100644
--- a/storage/innobase/fsp/fsp0fsp.cc
+++ b/storage/innobase/fsp/fsp0fsp.cc
@@ -1262,14 +1262,11 @@ static void fsp_free_page(fil_space_t* space, page_no_t offset, mtr_t* mtr)
 		return;
 	}
 
-	page_id_t drop_page_id(space->id, offset);
-
-	buf_block_t* block = buf_page_get_gen(
-			drop_page_id, 0, RW_X_LATCH, NULL,
-			BUF_GET_IF_IN_POOL, __FILE__, __LINE__,
-			mtr, NULL);
-
-	mtr->free(drop_page_id, block);
+	{
+		const page_id_t page_id(space->id, offset);
+		mtr->free(page_id);
+		buf_page_free(page_id, mtr, __FILE__, __LINE__);
+	}
 
 	const ulint	bit = offset % FSP_EXTENT_SIZE;
 
@@ -2733,14 +2730,10 @@ fseg_free_extent(
 
 	for (ulint i = 0; i < FSP_EXTENT_SIZE; i++) {
 		if (!xdes_is_free(descr, i)) {
-			const page_id_t drop_page_id(
+			const page_id_t page_id(
 				space->id, first_page_in_extent + i);
-
-			buf_block_t* block = buf_page_get_gen(
-				drop_page_id, 0, RW_X_LATCH, NULL,
-				BUF_GET_IF_IN_POOL, __FILE__, __LINE__,
-				mtr, NULL);
-			mtr->free(drop_page_id, block);
+			mtr->free(page_id);
+			buf_page_free(page_id, mtr, __FILE__, __LINE__);
 		}
 	}
 
@@ -2840,10 +2833,10 @@ fseg_free_step_func(
 		DBUG_RETURN(true);
 	}
 
-	ulint offset = fseg_get_nth_frag_page_no(inode, n, mtr);
-
 	fseg_free_page_low(
-		inode, iblock, space, offset, ahi, mtr);
+		inode, iblock, space,
+		fseg_get_nth_frag_page_no(inode, n, mtr),
+		ahi, mtr);
 
 	n = fseg_find_last_used_frag_page_slot(inode, mtr);
 
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h
index a8968259bfd..5fb76cb3027 100644
--- a/storage/innobase/include/buf0buf.h
+++ b/storage/innobase/include/buf0buf.h
@@ -336,6 +336,18 @@ the same set of mutexes or latches.
 @return pointer to the block */
 buf_page_t* buf_page_get_zip(const page_id_t page_id, ulint zip_size);
 
+/** Mark the page status as FREED for the given tablespace id and
+page number. If the page is not in the buffer pool then ignore it.
+@param[in]	page_id	page id
+@param[in,out]	mtr	mini-transaction
+@param[in]	file	file name
+@param[in]	line	line where called */
+void buf_page_free(
+	const page_id_t page_id,
+	mtr_t*		mtr,
+	const char*	file,
+	unsigned	line);
+
 /** This is the general function used to get access to a database page.
 @param[in]	page_id			page id
 @param[in]	zip_size		ROW_FORMAT=COMPRESSED page size, or 0
@@ -1192,7 +1204,7 @@ enum page_status_t {
 	X-latch and reset during page flush, while io_fix is in effect. */
 	INIT_ON_FLUSH,
 	/** FSP frees a page in buffer pool. protected by
-	buf_pool->zip_mutex or buf_block_t::mutex */
+	buf_pool_t::zip_mutex or buf_block_t::mutex */
 	FREED
 };
 
diff --git a/storage/innobase/include/mtr0log.h b/storage/innobase/include/mtr0log.h
index fffe776327b..1ea760e528a 100644
--- a/storage/innobase/include/mtr0log.h
+++ b/storage/innobase/include/mtr0log.h
@@ -510,22 +510,15 @@ inline void mtr_t::init(buf_block_t *b)
 
   m_log.close(log_write<INIT_PAGE>(b->page.id, &b->page));
   m_last_offset= FIL_PAGE_TYPE;
-  b->page.status = INIT_ON_FLUSH;
+  b->page.status= INIT_ON_FLUSH;
 }
 
 /** Free a page.
-@param id      page identifier
-@param block   block descriptor or NULL if drop page
-	       doesn't exist in buffer pool */
-inline void mtr_t::free(const page_id_t id, buf_block_t* block)
+@param id      page identifier */
+inline void mtr_t::free(const page_id_t id)
 {
   if (m_log_mode == MTR_LOG_ALL)
     m_log.close(log_write<FREE_PAGE>(id, nullptr));
-
-  fprintf(stderr, "freeing id %d:%d block %p\n",
-	  id.space(), id.page_no(), block);
-  if (block)
-    block->page.status = FREED;
 }
 
 /** Write an EXTENDED log record.
diff --git a/storage/innobase/include/mtr0mtr.h b/storage/innobase/include/mtr0mtr.h
index 245fa974608..f434bd8a535 100644
--- a/storage/innobase/include/mtr0mtr.h
+++ b/storage/innobase/include/mtr0mtr.h
@@ -488,9 +488,8 @@ struct mtr_t {
   @param[in,out]        b       buffer page */
   void init(buf_block_t *b);
   /** Free a page.
-  @param id      page identifier
-  @param block	 buffer block */
-  inline void free(const page_id_t id, buf_block_t *block);
+  @param id      page identifier */
+  inline void free(const page_id_t id);
   /** Partly initialize a B-tree page.
   @param block    B-tree page
   @param comp     false=ROW_FORMAT=REDUNDANT, true=COMPACT or DYNAMIC */