Merge lp:~laurynas-biveinis/percona-server/bug1269352-5.5 into lp:percona-server/5.5

[Laurynas Biveinis]

BT 37223

    Fix bug 1269352 (InnoDB: failing assertion: buf_page_in_file(bpage)
    below buf_flush_page_and_try_neighbors()), a follow-up to bug
    1227581.

    The latter bug attempted to fix race conditions involving buffer
    blocks in the middle of flush list relocations having
    BUF_BLOCK_REMOVE_HASH state, but the fix was not fully
    correct. buf_LRU_block_remove_hashed_page()/buf_LRU_free_block() will
    ake a page BUF_BLOCK_REMOVE_HASH while holding an LRU list mutex, a
    page hash X latch, and the block mutex.
    buf_flush_page_and_try_neighbors() may hold a flush list mutex
    instead. So, even though it checks for BUF_BLOCK_REMOVE_HASH pages,
    there is nothing to protect the flushing candidate page from becoming
    BUF_BLOCK_REMOVE_HASH after that check.

    Fix by reverting BUF_BLOCK_REMOVE_HASH check in
    buf_flush_page_and_try_neighbors() and adjusting it to accept
    BUF_BLOCK_REMOVE_HASH pages until the mutex release before the
    buf_flush_try_neighbors() call.

http://jenkins.percona.com/job/percona-server-5.5-param/935/

[Vlad Lesin (vlad-lesin)]

Jenkins testing does not cover such kind of fixes. I think we should consider using RQG results for such things.

[Laurynas Biveinis (laurynas-biveinis)]

Vlad -

Please see PQA-10.

=== modified file 'storage/innobase/buf/buf0flu.c'
--- storage/innobase/buf/buf0flu.c	2013-11-29 06:22:52 +0000
+++ storage/innobase/buf/buf0flu.c	2014-01-16 07:31:11 +0000
@@ -1605,17 +1605,8 @@
 		ut_ad(block_mutex);
 	}
 
-	if (UNIV_UNLIKELY(buf_page_get_state(bpage)
-			  == BUF_BLOCK_REMOVE_HASH)) {
-
-		/* In case we don't hold the LRU list mutex, we may see a page
-		that is about to be relocated on the flush list.  Do not
-		attempt to flush it.  */
-		ut_ad(flush_type == BUF_FLUSH_LIST);
-		return (flushed);
-	}
-
-	ut_a(buf_page_in_file(bpage));
+	ut_a(buf_page_in_file(bpage)
+	     || buf_page_get_state(bpage) == BUF_BLOCK_REMOVE_HASH);
 
 	if (buf_flush_ready_for_flush(bpage, flush_type)) {
 		ulint		space;
@@ -1631,8 +1622,10 @@
 
 		/* These fields are protected by both the
 		buffer pool mutex and block mutex. */
-		space = buf_page_get_space(bpage);
-		offset = buf_page_get_page_no(bpage);
+		/* Read the fields directly in order to avoid asserting on
+		BUF_BLOCK_REMOVE_HASH pages. */
+		space = bpage->space;
+		offset = bpage->offset;
 
 		if (flush_type == BUF_FLUSH_LRU) {
 			mutex_exit(block_mutex);