WT-3203 bulk-load state changes can race (#3318)

* The bulk-load state change (where multiple threads of control turn off the possibility of bulk-load in a tree), has always been able to race, but it's potentially dangerous now that turning off bulk-load involves calling `__wt_evict_file_exclusive_off()`. In the current tree, there's a diagnostic-only test that might fail because of this race.

* The WT_BTREE_NO_EVICTION flag is no longer set other than through the __wt_evict_file_exclusive_on/off functions; remove that flag and use the WT_BTREE.evict_disabled counter by itself.

2 files changed, 13 insertions, 14 deletions

diff --git a/src/include/btree.h b/src/include/btree.h
index 69ab2070eb9..fc7cd352883 100644
--- a/src/include/btree.h
+++ b/src/include/btree.h
@@ -120,7 +120,8 @@ struct __wt_btree {
 
 	WT_REF root;			/* Root page reference */
 	bool modified;			/* If the tree ever modified */
-	bool bulk_load_ok;		/* Bulk-load is a possibility */
+	uint8_t bulk_load_ok;		/* Bulk-load is a possibility
+					   (want a bool but needs atomic cas) */
 
 	WT_BM	*bm;			/* Block manager reference */
 	u_int	 block_header;		/* WT_PAGE_HEADER_BYTE_SIZE */
@@ -139,7 +140,7 @@ struct __wt_btree {
 	u_int	    evict_walk_period;	/* Skip this many LRU walks */
 	u_int	    evict_walk_saved;	/* Saved walk skips for checkpoints */
 	u_int	    evict_walk_skips;	/* Number of walks skipped */
-	u_int	    evict_disabled;	/* Eviction disabled count */
+	int	    evict_disabled;	/* Eviction disabled count */
 	volatile uint32_t evict_busy;	/* Count of threads in eviction */
 	int	    evict_start_type;	/* Start position for eviction walk
 					   (see WT_EVICT_WALK_START). */
@@ -162,14 +163,13 @@ struct __wt_btree {
 #define	WT_BTREE_LOOKASIDE	0x001000 /* Look-aside table */
 #define	WT_BTREE_LSM_PRIMARY	0x002000 /* Handle is current LSM primary */
 #define	WT_BTREE_NO_CHECKPOINT	0x004000 /* Disable checkpoints */
-#define	WT_BTREE_NO_EVICTION	0x008000 /* Disable eviction */
-#define	WT_BTREE_NO_LOGGING	0x010000 /* Disable logging */
-#define	WT_BTREE_NO_RECONCILE	0x020000 /* Allow splits, even with no evict */
-#define	WT_BTREE_REBALANCE	0x040000 /* Handle is for rebalance */
-#define	WT_BTREE_SALVAGE	0x080000 /* Handle is for salvage */
-#define	WT_BTREE_SKIP_CKPT	0x100000 /* Handle skipped checkpoint */
-#define	WT_BTREE_UPGRADE	0x200000 /* Handle is for upgrade */
-#define	WT_BTREE_VERIFY		0x400000 /* Handle is for verify */
+#define	WT_BTREE_NO_LOGGING	0x008000 /* Disable logging */
+#define	WT_BTREE_NO_RECONCILE	0x010000 /* Allow splits, even with no evict */
+#define	WT_BTREE_REBALANCE	0x020000 /* Handle is for rebalance */
+#define	WT_BTREE_SALVAGE	0x040000 /* Handle is for salvage */
+#define	WT_BTREE_SKIP_CKPT	0x080000 /* Handle skipped checkpoint */
+#define	WT_BTREE_UPGRADE	0x100000 /* Handle is for upgrade */
+#define	WT_BTREE_VERIFY		0x200000 /* Handle is for verify */
 	uint32_t flags;
 };
 
diff --git a/src/include/btree.i b/src/include/btree.i
index 6dda2428122..cec6f67e9bd 100644
--- a/src/include/btree.i
+++ b/src/include/btree.i
@@ -1401,7 +1401,7 @@ __wt_page_release(WT_SESSION_IMPL *session, WT_REF *ref, uint32_t flags)
 	if (page->read_gen != WT_READGEN_OLDEST ||
 	    LF_ISSET(WT_READ_NO_EVICT) ||
 	    F_ISSET(session, WT_SESSION_NO_EVICTION) ||
-	    F_ISSET(btree, WT_BTREE_NO_EVICTION) ||
+	    btree->evict_disabled > 0 ||
 	    !__wt_page_can_evict(session, ref, NULL))
 		return (__wt_hazard_clear(session, ref));
 
@@ -1521,7 +1521,7 @@ __wt_btree_lsm_over_size(WT_SESSION_IMPL *session, uint64_t maxsize)
 		return (false);
 
 	/* A tree that can be evicted always requires a switch. */
-	if (!F_ISSET(btree, WT_BTREE_NO_EVICTION))
+	if (btree->evict_disabled == 0)
 		return (true);
 
 	/* Check for a tree with a single leaf page. */
@@ -1569,8 +1569,7 @@ __wt_btree_lsm_switch_primary(WT_SESSION_IMPL *session, bool on)
 	}
 	if (!on && F_ISSET(btree, WT_BTREE_LSM_PRIMARY)) {
 		pindex = WT_INTL_INDEX_GET_SAFE(root);
-		if (!F_ISSET(btree, WT_BTREE_NO_EVICTION) ||
-		    pindex->entries != 1)
+		if (btree->evict_disabled == 0 || pindex->entries != 1)
 			return (0);
 		first = pindex->index[0];