[t:4874], move all usage of h->live_brts to brt_header.c

git-svn-id: file:///svn/toku/tokudb@43432 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/block_table.c

@@ -614,6 +614,7 @@ toku_block_verify_no_free_blocknums(BLOCK_TABLE bt) {
 //Verify there are no data blocks except root.
 void
 toku_block_verify_no_data_blocks_except_root_unlocked(BLOCK_TABLE bt, BLOCKNUM root) {
+    lock_for_blocktable(bt);
     //Relies on checkpoint having used optimize_translation
     assert(root.b >= RESERVED_BLOCKNUMS);
     assert(bt->current.smallest_never_used_blocknum.b == root.b + 1);
@@ -622,6 +623,7 @@ toku_block_verify_no_data_blocks_except_root_unlocked(BLOCK_TABLE bt, BLOCKNUM r
         BLOCKNUM b = make_blocknum(i);
         assert(bt->current.block_translation[b.b].size == size_is_free);
     }
+    unlock_for_blocktable(bt);
 }
 
 //Verify a blocknum is currently allocated.

newbrt/brt_header.c

@@ -532,6 +532,18 @@ int toku_remove_brtheader (struct brt_header* h, char **error_string, BOOL oplsn
     return r;
 }
 
+// gets the first existing BRT handle, if it exists. If no BRT handle exists
+// for this header, returns NULL
+BRT toku_brtheader_get_some_existing_brt(struct brt_header* h) {
+    BRT brt_ret = NULL;
+    toku_brtheader_lock(h);
+    if (toku_list_empty(&h->live_brts)) {
+        brt_ret = toku_list_struct(toku_list_head(&h->live_brts), struct brt, live_brt_link);
+    }
+    toku_brtheader_unlock(h);
+    return brt_ret;
+}
+
 // Purpose: set fields in brt_header to capture accountability info for start of HOT optimize.
 // Note: HOT accountability variables in header are modified only while holding header lock.
 //       (Header lock is really needed for touching the dirty bit, but it's useful and 

newbrt/brt_header.h

@@ -30,6 +30,8 @@ void toku_brtheader_note_brt_open(BRT live);
 int toku_brt_header_needed(struct brt_header* h);
 int toku_remove_brtheader (struct brt_header* h, char **error_string, BOOL oplsn_valid, LSN oplsn)  __attribute__ ((warn_unused_result));
 
+BRT toku_brtheader_get_some_existing_brt(struct brt_header* h);
+
 void toku_brt_header_note_hot_begin(BRT brt);
 void toku_brt_header_note_hot_complete(BRT brt, BOOL success, MSN msn_at_start_of_hot);
 

newbrt/logger.c

@@ -194,12 +194,10 @@ toku_logger_open_rollback(TOKULOGGER logger, CACHETABLE cachetable, BOOL create)
     r = toku_brt_open(t, ROLLBACK_CACHEFILE_NAME, create, create, cachetable, NULL_TXN);
     assert_zero(r);
     logger->rollback_cachefile = t->h->cf;
-    toku_brtheader_lock(t->h);
     //Verify it is empty
     assert(!t->h->panic);
     //Must have no data blocks (rollback logs or otherwise).
     toku_block_verify_no_data_blocks_except_root_unlocked(t->h->blocktable, t->h->root_blocknum);
-    toku_brtheader_unlock(t->h);
     BOOL is_empty;
     is_empty = toku_brt_is_empty_fast(t);
     assert(is_empty);
@@ -219,7 +217,6 @@ toku_logger_close_rollback(TOKULOGGER logger, BOOL recovery_failed) {
         BRT brt_to_close;
         {   //Find "brt"
             struct brt_header *h = toku_cachefile_get_userdata(cf);
-            toku_brtheader_lock(h);
             if (!h->panic && recovery_failed) {
                 r = toku_brt_header_set_panic(h, EINVAL, "Recovery failed");
                 assert_zero(r);
@@ -230,14 +227,10 @@ toku_logger_close_rollback(TOKULOGGER logger, BOOL recovery_failed) {
                 //Must have no data blocks (rollback logs or otherwise).
                 toku_block_verify_no_data_blocks_except_root_unlocked(h->blocktable, h->root_blocknum);
             }
-            assert(!toku_list_empty(&h->live_brts));  // there is always one brt associated with the header
-	    brt_to_close = toku_list_struct(toku_list_head(&h->live_brts), struct brt, live_brt_link);
+            assert(!h->dirty);
+            brt_to_close = toku_brtheader_get_some_existing_brt(h);
             assert(brt_to_close);
-	    assert(!brt_to_close->h->dirty);
-            toku_brtheader_unlock(h);
             {
-		// This almost doesn't work.  If there were anything in there, then the header might get dirtied by
-		// toku_brt_is_empty().  But it turns out absolutely nothing is in there, so it's OK to assert that it's empty.
                 BOOL is_empty;
                 is_empty = toku_brt_is_empty_fast(brt_to_close);
                 assert(is_empty);