MDEV-25018 [FATAL] InnoDB: Unable to read page (of a dropped tablespace)

- This issue is caused by commit deadec4 (MDEV-24569). InnoDB fails to read the change buffer bitmap page from dropped tablespace. In ibuf_bitmap_get_map_page_func(), InnoDB should fetch the page using BUF_GET_POSSIBLY_FREED mode. Callers of ibuf_bitmap_get_map_page() should be adjusted in that case.

Author: Thirunarayanan

storage/innobase/ibuf/ibuf0ibuf.cc

@@ -688,19 +688,15 @@ ibuf_bitmap_get_map_page_func(
 unsignedline,
 mtr_t*	mtr)
 {
-buf_block_t*	block = NULL;
-dberr_terr = DB_SUCCESS;
-
-block = buf_page_get_gen(
+buf_block_t* block = buf_page_get_gen(
 ibuf_bitmap_page_no_calc(page_id, zip_size),
-zip_size, RW_X_LATCH, NULL, BUF_GET, file, line, mtr, &err);
+zip_size, RW_X_LATCH, NULL, BUF_GET_POSSIBLY_FREED,
+file, line, mtr);
 
-if (err != DB_SUCCESS) {
-return NULL;
+if (block) {
+buf_block_dbg_add_level(block, SYNC_IBUF_BITMAP);
 }
 
-
-buf_block_dbg_add_level(block, SYNC_IBUF_BITMAP);
 return block;
 }
 
@@ -741,9 +737,12 @@ ibuf_set_free_bits_low(
 #endif /* UNIV_IBUF_DEBUG */
 const page_id_t id(block->page.id());
 
-ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(
-ibuf_bitmap_get_map_page(id, block->zip_size(), mtr),
-id, block->physical_size(), val, mtr);
+if (buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
+id, block->zip_size(), mtr)) {
+ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(
+bitmap_page, id, block->physical_size(),
+val, mtr);
+}
 }
 
 /************************************************************************//**
@@ -887,10 +886,13 @@ ibuf_update_free_bits_zip(
 buf_page_make_young(&block->page);
 }
 
-ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(
-ibuf_bitmap_get_map_page(block->page.id(), block->zip_size(),
- mtr),
-block->page.id(), block->physical_size(), after, mtr);
+if (buf_block_t* bitmap_page = ibuf_bitmap_get_map_page(
+block->page.id(), block->zip_size(), mtr)) {
+
+ibuf_bitmap_page_set_bits<IBUF_BITMAP_FREE>(
+bitmap_page, block->page.id(),
+block->physical_size(), after, mtr);
+}
 }
 
 /**********************************************************************//**
@@ -3669,14 +3671,15 @@ ibuf_insert_to_index_page_low(
  "InnoDB: is now probably corrupt. Please run CHECK TABLE on\n"
  "InnoDB: that table.\n", stderr);
 
-ib::error() << "page " << block->page.id() << ", size "
- << block->physical_size() << ", bitmap bits "
- << ibuf_bitmap_page_get_bits(
- ibuf_bitmap_get_map_page(block->page.id(),
- block->zip_size(),
- mtr)->frame,
- block->page.id(), block->zip_size(),
- IBUF_BITMAP_FREE, mtr);
+if (buf_block_t *bitmap_page = ibuf_bitmap_get_map_page(
+block->page.id(), block->zip_size(), mtr)) {
+
+ib::error() << "page " << block->page.id() << ", size "
+ << block->physical_size() << ", bitmap bits "
+ << ibuf_bitmap_page_get_bits(bitmap_page->frame,
+block->page.id(), block->zip_size(),
+IBUF_BITMAP_FREE, mtr);
+}
 
 ib::error() << BUG_REPORT_MSG;