X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Ftdb2%2Ffree.c;h=c03680cfd943557d883daeee50b5ede41b707e75;hb=48241893712414cf3d3992a7dbe3d119925559ff;hp=7ede24616efc78df4e16eda260ace518bbd88755;hpb=40bab4d5df030f84a63d9c6cb1348d8f27442a0a;p=ccan

diff --git a/ccan/tdb2/free.c b/ccan/tdb2/free.c
index 7ede2461..c03680cf 100644
--- a/ccan/tdb2/free.c
+++ b/ccan/tdb2/free.c
@@ -103,55 +103,96 @@ static tdb_off_t find_free_head(struct tdb_context *tdb,
 				    bucket, TDB_FREE_BUCKETS);
 }
 
+static void check_list(struct tdb_context *tdb, tdb_off_t b_off)
+{
+#ifdef CCAN_TDB2_DEBUG
+	tdb_off_t off, prev = 0, first;
+	struct tdb_free_record r;
+
+	first = off = tdb_read_off(tdb, b_off);
+	while (off != 0) {
+		tdb_read_convert(tdb, off, &r, sizeof(r));
+		if (frec_magic(&r) != TDB_FREE_MAGIC)
+			abort();
+		if (prev && frec_prev(&r) != prev)
+			abort();
+		prev = off;
+		off = r.next;
+	}
+
+	if (first) {
+		tdb_read_convert(tdb, first, &r, sizeof(r));
+		if (frec_prev(&r) != prev)
+			abort();
+	}
+#endif
+}
+
 /* Remove from free bucket. */
 static enum TDB_ERROR remove_from_list(struct tdb_context *tdb,
 				       tdb_off_t b_off, tdb_off_t r_off,
 				       const struct tdb_free_record *r)
 {
-	tdb_off_t off;
+	tdb_off_t off, prev_next, head;
 	enum TDB_ERROR ecode;
 
-	/* Front of list? */
-	if (frec_prev(r) == 0) {
-		off = b_off;
-	} else {
-		off = frec_prev(r) + offsetof(struct tdb_free_record, next);
-	}
-
-#ifdef CCAN_TDB2_DEBUG
-	if (tdb_read_off(tdb, off) != r_off) {
-		return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
-				  "remove_from_list:"
-				  " %llu bad prev in list %llu",
-				  (long long)r_off, (long long)b_off);
-	}
-#endif
+	/* Is this only element in list?  Zero out bucket, and we're done. */
+	if (frec_prev(r) == r_off)
+		return tdb_write_off(tdb, b_off, 0);
 
-	/* r->prev->next = r->next */
-	ecode = tdb_write_off(tdb, off, r->next);
-	if (ecode != TDB_SUCCESS) {
-		return ecode;
-	}
+	/* off = &r->prev->next */
+	off = frec_prev(r) + offsetof(struct tdb_free_record, next);
 
-	if (r->next != 0) {
-		off = r->next + offsetof(struct tdb_free_record,magic_and_prev);
-		/* r->next->prev = r->prev */
+	/* Get prev->next */
+	prev_next = tdb_read_off(tdb, off);
+	if (TDB_OFF_IS_ERR(prev_next))
+		return prev_next;
 
+	/* If prev->next == 0, we were head: update bucket to point to next. */
+	if (prev_next == 0) {
 #ifdef CCAN_TDB2_DEBUG
-		if (tdb_read_off(tdb, off) & TDB_OFF_MASK != r_off) {
+		if (tdb_read_off(tdb, b_off) != r_off) {
 			return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 					  "remove_from_list:"
-					  " %llu bad list %llu",
-					  (long long)r_off, (long long)b_off);
+					  " %llu head %llu on list %llu",
+					  (long long)r_off,
+					  (long long)tdb_read_off(tdb, b_off),
+					  (long long)b_off);
 		}
 #endif
-
-		ecode = tdb_write_off(tdb, off, r->magic_and_prev);
-		if (ecode != TDB_SUCCESS) {
+		ecode = tdb_write_off(tdb, b_off, r->next);
+		if (ecode != TDB_SUCCESS)
+			return ecode;
+	} else {
+		/* r->prev->next = r->next */
+		ecode = tdb_write_off(tdb, off, r->next);
+		if (ecode != TDB_SUCCESS)
 			return ecode;
-		}
 	}
-	return TDB_SUCCESS;
+
+	/* If we were the tail, off = &head->prev. */
+	if (r->next == 0) {
+		head = tdb_read_off(tdb, b_off);
+		if (TDB_OFF_IS_ERR(head))
+			return head;
+		off = head + offsetof(struct tdb_free_record, magic_and_prev);
+	} else {
+		/* off = &r->next->prev */
+		off = r->next + offsetof(struct tdb_free_record,
+					 magic_and_prev);
+	}
+
+#ifdef CCAN_TDB2_DEBUG
+	/* *off == r */
+	if ((tdb_read_off(tdb, off) & TDB_OFF_MASK) != r_off) {
+		return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+				  "remove_from_list:"
+				  " %llu bad prev in list %llu",
+				  (long long)r_off, (long long)b_off);
+	}
+#endif
+	/* r->next->prev = r->prev */
+	return tdb_write_off(tdb, off, r->magic_and_prev);
 }
 
 /* Enqueue in this free bucket. */
@@ -162,13 +203,12 @@ static enum TDB_ERROR enqueue_in_free(struct tdb_context *tdb,
 {
 	struct tdb_free_record new;
 	enum TDB_ERROR ecode;
+	tdb_off_t prev;
 	uint64_t magic = (TDB_FREE_MAGIC << (64 - TDB_OFF_UPPER_STEAL));
 
 	/* We only need to set ftable_and_len; rest is set in enqueue_in_free */
 	new.ftable_and_len = ((uint64_t)tdb->ftable << (64 - TDB_OFF_UPPER_STEAL))
 		| len;
-	/* prev = 0. */
-	new.magic_and_prev = magic;
 
 	/* new->next = head. */
 	new.next = tdb_read_off(tdb, b_off);
@@ -176,19 +216,22 @@ static enum TDB_ERROR enqueue_in_free(struct tdb_context *tdb,
 		return new.next;
 	}
 
-	if (new.next) {
-#ifdef CCAN_TDB2_DEBUG
-		if (tdb_read_off(tdb,
-				 new.next + offsetof(struct tdb_free_record,
-						     magic_and_prev))
-		    != magic) {
+	/* First element?  Prev points to ourselves. */
+	if (!new.next) {
+		new.magic_and_prev = (magic | off);
+	} else {
+		/* new->prev = next->prev */
+		prev = tdb_read_off(tdb,
+				    new.next + offsetof(struct tdb_free_record,
+							magic_and_prev));
+		new.magic_and_prev = prev;
+		if (frec_magic(&new) != TDB_FREE_MAGIC) {
 			return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
 					  "enqueue_in_free: %llu bad head"
 					  " prev %llu",
 					  (long long)new.next,
-					  (long long)b_off);
+					  (long long)prev);
 		}
-#endif
 		/* next->prev = new. */
 		ecode = tdb_write_off(tdb, new.next
 				      + offsetof(struct tdb_free_record,
@@ -197,6 +240,20 @@ static enum TDB_ERROR enqueue_in_free(struct tdb_context *tdb,
 		if (ecode != TDB_SUCCESS) {
 			return ecode;
 		}
+
+#ifdef CCAN_TDB2_DEBUG
+		prev = tdb_read_off(tdb, frec_prev(&new)
+				    + offsetof(struct tdb_free_record, next));
+		if (prev != 0) {
+			return tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+					  "enqueue_in_free:"
+					  " %llu bad tail next ptr %llu",
+					  (long long)frec_prev(&new)
+					  + offsetof(struct tdb_free_record,
+						     next),
+					  (long long)prev);
+		}
+#endif
 	}
 	/* head = new */
 	ecode = tdb_write_off(tdb, b_off, off);
@@ -226,6 +283,7 @@ enum TDB_ERROR add_free_record(struct tdb_context *tdb,
 	}
 
 	ecode = enqueue_in_free(tdb, b_off, off, len);
+	check_list(tdb, b_off);
 	tdb_unlock_free_bucket(tdb, b_off);
 	return ecode;
 }
@@ -284,7 +342,7 @@ static tdb_bool_err coalesce(struct tdb_context *tdb,
 	struct tdb_free_record rec;
 	enum TDB_ERROR ecode;
 
-	add_stat(tdb, alloc_coalesce_tried, 1);
+	tdb->stats.alloc_coalesce_tried++;
 	end = off + sizeof(struct tdb_used_record) + data_len;
 
 	while (end < tdb->file->map_size) {
@@ -318,7 +376,7 @@ static tdb_bool_err coalesce(struct tdb_context *tdb,
 		/* We may be violating lock order here, so best effort. */
 		if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT)
 		    != TDB_SUCCESS) {
-			add_stat(tdb, alloc_coalesce_lockfail, 1);
+			tdb->stats.alloc_coalesce_lockfail++;
 			break;
 		}
 
@@ -330,19 +388,20 @@ static tdb_bool_err coalesce(struct tdb_context *tdb,
 		}
 
 		if (unlikely(frec_magic(&rec) != TDB_FREE_MAGIC)) {
-			add_stat(tdb, alloc_coalesce_race, 1);
+			tdb->stats.alloc_coalesce_race++;
 			tdb_unlock_free_bucket(tdb, nb_off);
 			break;
 		}
 
 		if (unlikely(frec_ftable(&rec) != ftable)
 		    || unlikely(size_to_bucket(frec_len(&rec)) != bucket)) {
-			add_stat(tdb, alloc_coalesce_race, 1);
+			tdb->stats.alloc_coalesce_race++;
 			tdb_unlock_free_bucket(tdb, nb_off);
 			break;
 		}
 
 		ecode = remove_from_list(tdb, nb_off, end, &rec);
+		check_list(tdb, nb_off);
 		if (ecode != TDB_SUCCESS) {
 			tdb_unlock_free_bucket(tdb, nb_off);
 			goto err;
@@ -350,7 +409,7 @@ static tdb_bool_err coalesce(struct tdb_context *tdb,
 
 		end += sizeof(struct tdb_used_record) + frec_len(&rec);
 		tdb_unlock_free_bucket(tdb, nb_off);
-		add_stat(tdb, alloc_coalesce_num_merged, 1);
+		tdb->stats.alloc_coalesce_num_merged++;
 	}
 
 	/* Didn't find any adjacent free? */
@@ -371,6 +430,7 @@ static tdb_bool_err coalesce(struct tdb_context *tdb,
 	}
 
 	ecode = remove_from_list(tdb, b_off, off, &rec);
+	check_list(tdb, b_off);
 	if (ecode != TDB_SUCCESS) {
 		goto err;
 	}
@@ -386,7 +446,7 @@ static tdb_bool_err coalesce(struct tdb_context *tdb,
 		goto err;
 	}
 
-	add_stat(tdb, alloc_coalesce_succeeded, 1);
+	tdb->stats.alloc_coalesce_succeeded++;
 	tdb_unlock_free_bucket(tdb, b_off);
 
 	ecode = add_free_record(tdb, off, end - off);
@@ -416,7 +476,7 @@ static tdb_off_t lock_and_alloc(struct tdb_context *tdb,
 	size_t size = adjust_size(keylen, datalen);
 	enum TDB_ERROR ecode;
 
-	add_stat(tdb, allocs, 1);
+	tdb->stats.allocs++;
 again:
 	b_off = bucket_off(ftable_off, bucket);
 
@@ -471,7 +531,7 @@ again:
 			best = *r;
 		}
 
-		if (frec_len(&best) < size * multiplier && best_off) {
+		if (frec_len(&best) <= size * multiplier && best_off) {
 			tdb_access_release(tdb, r);
 			break;
 		}
@@ -502,6 +562,7 @@ again:
 
 		/* We're happy with this size: take it. */
 		ecode = remove_from_list(tdb, b_off, best_off, &best);
+		check_list(tdb, b_off);
 		if (ecode != TDB_SUCCESS) {
 			goto unlock_err;
 		}
@@ -535,7 +596,7 @@ again:
 		/* Bucket of leftover will be <= current bucket, so nested
 		 * locking is allowed. */
 		if (leftover) {
-			add_stat(tdb, alloc_leftover, 1);
+			tdb->stats.alloc_leftover++;
 			ecode = add_free_record(tdb,
 						best_off + sizeof(rec)
 						+ frec_len(&best) - leftover,
@@ -588,9 +649,9 @@ static tdb_off_t get_free(struct tdb_context *tdb,
 				return off;
 			if (off != 0) {
 				if (b == start_b)
-					add_stat(tdb, alloc_bucket_exact, 1);
+					tdb->stats.alloc_bucket_exact++;
 				if (b == TDB_FREE_BUCKETS - 1)
-					add_stat(tdb, alloc_bucket_max, 1);
+					tdb->stats.alloc_bucket_max++;
 				/* Worked?  Stay using this list. */
 				tdb->ftable_off = ftable_off;
 				tdb->ftable = ftable;
@@ -652,13 +713,10 @@ enum TDB_ERROR set_header(struct tdb_context *tdb,
 /* Expand the database. */
 static enum TDB_ERROR tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 {
-	uint64_t old_size;
+	uint64_t old_size, rec_size, map_size;
 	tdb_len_t wanted;
 	enum TDB_ERROR ecode;
 
-	/* We need room for the record header too. */
-	wanted = sizeof(struct tdb_used_record) + size;
-
 	/* Need to hold a hash lock to expand DB: transactions rely on it. */
 	if (!(tdb->flags & TDB_NOLOCK)
 	    && !tdb->file->allrecord_lock.count && !tdb_has_hash_locks(tdb)) {
@@ -666,14 +724,6 @@ static enum TDB_ERROR tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 				  "tdb_expand: must hold lock during expand");
 	}
 
-	/* always make room for at least 100 more records, and at
-           least 25% more space. */
-	if (size * TDB_EXTENSION_FACTOR > tdb->file->map_size / 4)
-		wanted = size * TDB_EXTENSION_FACTOR;
-	else
-		wanted = tdb->file->map_size / 4;
-	wanted = adjust_size(0, wanted);
-
 	/* Only one person can expand file at a time. */
 	ecode = tdb_lock_expand(tdb, F_WRLCK);
 	if (ecode != TDB_SUCCESS) {
@@ -688,6 +738,32 @@ static enum TDB_ERROR tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 		return TDB_SUCCESS;
 	}
 
+	/* limit size in order to avoid using up huge amounts of memory for
+	 * in memory tdbs if an oddball huge record creeps in */
+	if (size > 100 * 1024) {
+		rec_size = size * 2;
+	} else {
+		rec_size = size * 100;
+	}
+
+	/* always make room for at least rec_size more records, and at
+	   least 25% more space. if the DB is smaller than 100MiB,
+	   otherwise grow it by 10% only. */
+	if (old_size > 100 * 1024 * 1024) {
+		map_size = old_size / 10;
+	} else {
+		map_size = old_size / 4;
+	}
+
+	if (map_size > rec_size) {
+		wanted = map_size;
+	} else {
+		wanted = rec_size;
+	}
+
+	/* We need room for the record header too. */
+	wanted = adjust_size(0, sizeof(struct tdb_used_record) + wanted);
+
 	ecode = tdb->methods->expand_file(tdb, wanted);
 	if (ecode != TDB_SUCCESS) {
 		tdb_unlock_expand(tdb, F_WRLCK);
@@ -697,7 +773,7 @@ static enum TDB_ERROR tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 	/* We need to drop this lock before adding free record. */
 	tdb_unlock_expand(tdb, F_WRLCK);
 
-	add_stat(tdb, expands, 1);
+	tdb->stats.expands++;
 	return add_free_record(tdb, old_size, wanted);
 }