X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb2%2Ffree.c;h=d2285567eb0efdf56dfd8d96ec0650845ef403e0;hp=bface0a319fb94504059160ed9247db493e16e9f;hb=a0e0927e1f34d80fd4d4ee2d68fa2acb94ae9eb2;hpb=850c5cfed46cd4f38df79783791969c7b30ad9da

diff --git a/ccan/tdb2/free.c b/ccan/tdb2/free.c
index bface0a3..d2285567 100644
--- a/ccan/tdb2/free.c
+++ b/ccan/tdb2/free.c
@@ -59,7 +59,7 @@ tdb_off_t next_ftable(struct tdb_context *tdb, tdb_off_t ftable)
 	return tdb_read_off(tdb, ftable + offsetof(struct tdb_freetable,next));
 }
 
-int tdb_ftable_init(struct tdb_context *tdb)
+enum TDB_ERROR tdb_ftable_init(struct tdb_context *tdb)
 {
 	/* Use reservoir sampling algorithm to select a free list at random. */
 	unsigned int rnd, max = 0, count = 0;
@@ -69,8 +69,9 @@ int tdb_ftable_init(struct tdb_context *tdb)
 	tdb->ftable = 0;
 
 	while (off) {
-		if (off == TDB_OFF_ERR)
-			return -1;
+		if (TDB_OFF_IS_ERR(off)) {
+			return off;
+		}
 
 		rnd = random();
 		if (rnd >= max) {
@@ -82,7 +83,7 @@ int tdb_ftable_init(struct tdb_context *tdb)
 		off = next_ftable(tdb, off);
 		count++;
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
 /* Offset of a given bucket. */
@@ -92,7 +93,7 @@ tdb_off_t bucket_off(tdb_off_t ftable_off, unsigned bucket)
 		+ bucket * sizeof(tdb_off_t);
 }
 
-/* Returns free_buckets + 1, or list number to search. */
+/* Returns free_buckets + 1, or list number to search, or -ve error. */
 static tdb_off_t find_free_head(struct tdb_context *tdb,
 				tdb_off_t ftable_off,
 				tdb_off_t bucket)
@@ -103,11 +104,12 @@ static tdb_off_t find_free_head(struct tdb_context *tdb,
 }
 
 /* Remove from free bucket. */
-static int remove_from_list(struct tdb_context *tdb,
-			    tdb_off_t b_off, tdb_off_t r_off,
-			    const struct tdb_free_record *r)
+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;
+	enum TDB_ERROR ecode;
 
 	/* Front of list? */
 	if (frec_prev(r) == 0) {
@@ -118,16 +120,17 @@ static int remove_from_list(struct tdb_context *tdb,
 
 #ifdef CCAN_TDB2_DEBUG
 	if (tdb_read_off(tdb, off) != r_off) {
-		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);
-		return -1;
+		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->prev->next = r->next */
-	if (tdb_write_off(tdb, off, r->next)) {
-		return -1;
+	ecode = tdb_write_off(tdb, off, r->next);
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
 	}
 
 	if (r->next != 0) {
@@ -136,27 +139,29 @@ static int remove_from_list(struct tdb_context *tdb,
 
 #ifdef CCAN_TDB2_DEBUG
 		if (tdb_read_off(tdb, off) & TDB_OFF_MASK != r_off) {
-			tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
-				   "remove_from_list: %llu bad list %llu",
-				   (long long)r_off, (long long)b_off);
-			return -1;
+			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);
 		}
 #endif
 
-		if (tdb_write_off(tdb, off, r->magic_and_prev)) {
-			return -1;
+		ecode = tdb_write_off(tdb, off, r->magic_and_prev);
+		if (ecode != TDB_SUCCESS) {
+			return ecode;
 		}
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
 /* Enqueue in this free bucket. */
-static int enqueue_in_free(struct tdb_context *tdb,
-			   tdb_off_t b_off,
-			   tdb_off_t off,
-			   tdb_len_t len)
+static enum TDB_ERROR enqueue_in_free(struct tdb_context *tdb,
+				      tdb_off_t b_off,
+				      tdb_off_t off,
+				      tdb_len_t len)
 {
 	struct tdb_free_record new;
+	enum TDB_ERROR ecode;
 	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 */
@@ -167,8 +172,9 @@ static int enqueue_in_free(struct tdb_context *tdb,
 
 	/* new->next = head. */
 	new.next = tdb_read_off(tdb, b_off);
-	if (new.next == TDB_OFF_ERR)
-		return -1;
+	if (TDB_OFF_IS_ERR(new.next)) {
+		return new.next;
+	}
 
 	if (new.next) {
 #ifdef CCAN_TDB2_DEBUG
@@ -176,34 +182,37 @@ static int enqueue_in_free(struct tdb_context *tdb,
 				 new.next + offsetof(struct tdb_free_record,
 						     magic_and_prev))
 		    != magic) {
-			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);
-			return -1;
+			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);
 		}
 #endif
 		/* next->prev = new. */
-		if (tdb_write_off(tdb, new.next
-				  + offsetof(struct tdb_free_record,
-					     magic_and_prev),
-				  off | magic) != 0)
-			return -1;
+		ecode = tdb_write_off(tdb, new.next
+				      + offsetof(struct tdb_free_record,
+						 magic_and_prev),
+				      off | magic);
+		if (ecode != TDB_SUCCESS) {
+			return ecode;
+		}
 	}
 	/* head = new */
-	if (tdb_write_off(tdb, b_off, off) != 0)
-		return -1;
+	ecode = tdb_write_off(tdb, b_off, off);
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
+	}
 
 	return tdb_write_convert(tdb, off, &new, sizeof(new));
 }
 
 /* List need not be locked. */
-int add_free_record(struct tdb_context *tdb,
-		    tdb_off_t off, tdb_len_t len_with_header)
+enum TDB_ERROR add_free_record(struct tdb_context *tdb,
+			       tdb_off_t off, tdb_len_t len_with_header)
 {
 	tdb_off_t b_off;
 	tdb_len_t len;
-	int ret;
 	enum TDB_ERROR ecode;
 
 	assert(len_with_header >= sizeof(struct tdb_free_record));
@@ -213,13 +222,12 @@ int add_free_record(struct tdb_context *tdb,
 	b_off = bucket_off(tdb->ftable_off, size_to_bucket(len));
 	ecode = tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT);
 	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		return -1;
+		return ecode;
 	}
 
-	ret = enqueue_in_free(tdb, b_off, off, len);
+	ecode = enqueue_in_free(tdb, b_off, off, len);
 	tdb_unlock_free_bucket(tdb, b_off);
-	return ret;
+	return ecode;
 }
 
 static size_t adjust_size(size_t keylen, size_t datalen)
@@ -258,17 +266,23 @@ static tdb_off_t ftable_offset(struct tdb_context *tdb, unsigned int ftable)
 		return tdb->ftable_off;
 
 	off = first_ftable(tdb);
-	for (i = 0; i < ftable; i++)
+	for (i = 0; i < ftable; i++) {
+		if (TDB_OFF_IS_ERR(off)) {
+			break;
+		}
 		off = next_ftable(tdb, off);
+	}
 	return off;
 }
 
 /* Note: we unlock the current bucket if we coalesce or fail. */
-static int coalesce(struct tdb_context *tdb,
-		    tdb_off_t off, tdb_off_t b_off, tdb_len_t data_len)
+static tdb_bool_err coalesce(struct tdb_context *tdb,
+			     tdb_off_t off, tdb_off_t b_off,
+			     tdb_len_t data_len)
 {
 	tdb_off_t end;
 	struct tdb_free_record rec;
+	enum TDB_ERROR ecode;
 
 	add_stat(tdb, alloc_coalesce_tried, 1);
 	end = off + sizeof(struct tdb_used_record) + data_len;
@@ -279,8 +293,10 @@ static int coalesce(struct tdb_context *tdb,
 		unsigned ftable, bucket;
 
 		r = tdb_access_read(tdb, end, sizeof(*r), true);
-		if (!r)
+		if (TDB_PTR_IS_ERR(r)) {
+			ecode = TDB_PTR_ERR(r);
 			goto err;
+		}
 
 		if (frec_magic(r) != TDB_FREE_MAGIC
 		    || frec_ftable(r) == TDB_FTABLE_NONE) {
@@ -290,7 +306,13 @@ static int coalesce(struct tdb_context *tdb,
 
 		ftable = frec_ftable(r);
 		bucket = size_to_bucket(frec_len(r));
-		nb_off = bucket_off(ftable_offset(tdb, ftable), bucket);
+		nb_off = ftable_offset(tdb, ftable);
+		if (TDB_OFF_IS_ERR(nb_off)) {
+			tdb_access_release(tdb, r);
+			ecode = nb_off;
+			goto err;
+		}
+		nb_off = bucket_off(nb_off, bucket);
 		tdb_access_release(tdb, r);
 
 		/* We may be violating lock order here, so best effort. */
@@ -301,7 +323,8 @@ static int coalesce(struct tdb_context *tdb,
 		}
 
 		/* Now we have lock, re-check. */
-		if (tdb_read_convert(tdb, end, &rec, sizeof(rec))) {
+		ecode = tdb_read_convert(tdb, end, &rec, sizeof(rec));
+		if (ecode != TDB_SUCCESS) {
 			tdb_unlock_free_bucket(tdb, nb_off);
 			goto err;
 		}
@@ -319,7 +342,8 @@ static int coalesce(struct tdb_context *tdb,
 			break;
 		}
 
-		if (remove_from_list(tdb, nb_off, end, &rec) == -1) {
+		ecode = remove_from_list(tdb, nb_off, end, &rec);
+		if (ecode != TDB_SUCCESS) {
 			tdb_unlock_free_bucket(tdb, nb_off);
 			goto err;
 		}
@@ -331,42 +355,50 @@ static int coalesce(struct tdb_context *tdb,
 
 	/* Didn't find any adjacent free? */
 	if (end == off + sizeof(struct tdb_used_record) + data_len)
-		return 0;
+		return false;
 
 	/* OK, expand initial record */
-	if (tdb_read_convert(tdb, off, &rec, sizeof(rec)))
+	ecode = tdb_read_convert(tdb, off, &rec, sizeof(rec));
+	if (ecode != TDB_SUCCESS) {
 		goto err;
+	}
 
 	if (frec_len(&rec) != data_len) {
-		tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
-			   "coalesce: expected data len %zu not %zu",
-			   (size_t)data_len, (size_t)frec_len(&rec));
+		ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+				   "coalesce: expected data len %zu not %zu",
+				   (size_t)data_len, (size_t)frec_len(&rec));
 		goto err;
 	}
 
-	if (remove_from_list(tdb, b_off, off, &rec) == -1)
+	ecode = remove_from_list(tdb, b_off, off, &rec);
+	if (ecode != TDB_SUCCESS) {
 		goto err;
+	}
 
 	/* We have to drop this to avoid deadlocks, so make sure record
 	 * doesn't get coalesced by someone else! */
 	rec.ftable_and_len = (TDB_FTABLE_NONE << (64 - TDB_OFF_UPPER_STEAL))
 		| (end - off - sizeof(struct tdb_used_record));
-	if (tdb_write_off(tdb, off + offsetof(struct tdb_free_record,
-					      ftable_and_len),
-			  rec.ftable_and_len) != 0)
+	ecode = tdb_write_off(tdb, off + offsetof(struct tdb_free_record,
+						  ftable_and_len),
+			      rec.ftable_and_len);
+	if (ecode != TDB_SUCCESS) {
 		goto err;
+	}
 
 	add_stat(tdb, alloc_coalesce_succeeded, 1);
 	tdb_unlock_free_bucket(tdb, b_off);
 
-	if (add_free_record(tdb, off, end - off) == -1)
-		return -1;
-	return 1;
+	ecode = add_free_record(tdb, off, end - off);
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
+	}
+	return true;
 
 err:
 	/* To unify error paths, we *always* unlock bucket on error. */
 	tdb_unlock_free_bucket(tdb, b_off);
-	return -1;
+	return ecode;
 }
 
 /* We need size bytes to put our key and data in. */
@@ -392,8 +424,7 @@ again:
 	/* Lock this bucket. */
 	ecode = tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT);
 	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		return TDB_OFF_ERR;
+		return ecode;
 	}
 
 	best.ftable_and_len = -1ULL;
@@ -408,23 +439,30 @@ again:
 	/* Walk the list to see if any are large enough, getting less fussy
 	 * as we go. */
 	off = tdb_read_off(tdb, b_off);
-	if (unlikely(off == TDB_OFF_ERR))
+	if (TDB_OFF_IS_ERR(off)) {
+		ecode = off;
 		goto unlock_err;
+	}
 
 	while (off) {
 		const struct tdb_free_record *r;
 		tdb_len_t len;
 		tdb_off_t next;
+		int coal;
 
 		r = tdb_access_read(tdb, off, sizeof(*r), true);
-		if (!r)
+		if (TDB_PTR_IS_ERR(r)) {
+			ecode = TDB_PTR_ERR(r);
 			goto unlock_err;
+		}
 
 		if (frec_magic(r) != TDB_FREE_MAGIC) {
 			tdb_access_release(tdb, r);
-			tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
-				 "lock_and_alloc: %llu non-free 0x%llx",
-				 (long long)off, (long long)r->magic_and_prev);
+			ecode = tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+					   "lock_and_alloc:"
+					   " %llu non-free 0x%llx",
+					   (long long)off,
+					   (long long)r->magic_and_prev);
 			goto unlock_err;
 		}
 
@@ -445,14 +483,15 @@ again:
 		tdb_access_release(tdb, r);
 
 		/* Since we're going slow anyway, try coalescing here. */
-		switch (coalesce(tdb, off, b_off, len)) {
-		case -1:
-			/* This has already unlocked on error. */
-			return -1;
-		case 1:
+		coal = coalesce(tdb, off, b_off, len);
+		if (coal == 1) {
 			/* This has unlocked list, restart. */
 			goto again;
 		}
+		if (coal < 0) {
+			/* This has already unlocked on error. */
+			return coal;
+		}
 		off = next;
 	}
 
@@ -462,8 +501,10 @@ again:
 		size_t leftover;
 
 		/* We're happy with this size: take it. */
-		if (remove_from_list(tdb, b_off, best_off, &best) != 0)
+		ecode = remove_from_list(tdb, b_off, best_off, &best);
+		if (ecode != TDB_SUCCESS) {
 			goto unlock_err;
+		}
 
 		leftover = record_leftover(keylen, datalen, want_extra,
 					   frec_len(&best));
@@ -471,22 +512,28 @@ again:
 		assert(keylen + datalen + leftover <= frec_len(&best));
 		/* We need to mark non-free before we drop lock, otherwise
 		 * coalesce() could try to merge it! */
-		if (set_header(tdb, &rec, magic, keylen, datalen,
-			       frec_len(&best) - leftover, hashlow) != 0)
+		ecode = set_header(tdb, &rec, magic, keylen, datalen,
+				   frec_len(&best) - leftover, hashlow);
+		if (ecode != TDB_SUCCESS) {
 			goto unlock_err;
+		}
 
-		if (tdb_write_convert(tdb, best_off, &rec, sizeof(rec)) != 0)
+		ecode = tdb_write_convert(tdb, best_off, &rec, sizeof(rec));
+		if (ecode != TDB_SUCCESS) {
 			goto unlock_err;
+		}
 
 		/* Bucket of leftover will be <= current bucket, so nested
 		 * locking is allowed. */
 		if (leftover) {
 			add_stat(tdb, alloc_leftover, 1);
-			if (add_free_record(tdb,
-					    best_off + sizeof(rec)
-					    + frec_len(&best) - leftover,
-					    leftover))
-				best_off = TDB_OFF_ERR;
+			ecode = add_free_record(tdb,
+						best_off + sizeof(rec)
+						+ frec_len(&best) - leftover,
+						leftover);
+			if (ecode != TDB_SUCCESS) {
+				best_off = ecode;
+			}
 		}
 		tdb_unlock_free_bucket(tdb, b_off);
 
@@ -498,16 +545,16 @@ again:
 
 unlock_err:
 	tdb_unlock_free_bucket(tdb, b_off);
-	return TDB_OFF_ERR;
+	return ecode;
 }
 
-/* Get a free block from current free list, or 0 if none. */
+/* Get a free block from current free list, or 0 if none, -ve on error. */
 static tdb_off_t get_free(struct tdb_context *tdb,
 			  size_t keylen, size_t datalen, bool want_extra,
 			  unsigned magic, unsigned hashlow)
 {
 	tdb_off_t off, ftable_off;
-	unsigned start_b, b, ftable;
+	tdb_off_t start_b, b, ftable;
 	bool wrapped = false;
 
 	/* If they are growing, add 50% to get to higher bucket. */
@@ -528,8 +575,8 @@ static tdb_off_t get_free(struct tdb_context *tdb,
 			off = lock_and_alloc(tdb, ftable_off,
 					     b, keylen, datalen, want_extra,
 					     magic, hashlow);
-			if (off == TDB_OFF_ERR)
-				return TDB_OFF_ERR;
+			if (TDB_OFF_IS_ERR(off))
+				return off;
 			if (off != 0) {
 				if (b == start_b)
 					add_stat(tdb, alloc_bucket_exact, 1);
@@ -543,13 +590,23 @@ static tdb_off_t get_free(struct tdb_context *tdb,
 			/* Didn't work.  Try next bucket. */
 		}
 
+		if (TDB_OFF_IS_ERR(b)) {
+			return b;
+		}
+
 		/* Hmm, try next table. */
 		ftable_off = next_ftable(tdb, ftable_off);
+		if (TDB_OFF_IS_ERR(ftable_off)) {
+			return ftable_off;
+		}
 		ftable++;
 
 		if (ftable_off == 0) {
 			wrapped = true;
 			ftable_off = first_ftable(tdb);
+			if (TDB_OFF_IS_ERR(ftable_off)) {
+				return ftable_off;
+			}
 			ftable = 0;
 		}
 	}
@@ -557,10 +614,10 @@ static tdb_off_t get_free(struct tdb_context *tdb,
 	return 0;
 }
 
-int set_header(struct tdb_context *tdb,
-	       struct tdb_used_record *rec,
-	       unsigned magic, uint64_t keylen, uint64_t datalen,
-	       uint64_t actuallen, unsigned hashlow)
+enum TDB_ERROR set_header(struct tdb_context *tdb,
+			  struct tdb_used_record *rec,
+			  unsigned magic, uint64_t keylen, uint64_t datalen,
+			  uint64_t actuallen, unsigned hashlow)
 {
 	uint64_t keybits = (fls64(keylen) + 1) / 2;
 
@@ -575,17 +632,16 @@ int set_header(struct tdb_context *tdb,
 	if (rec_key_length(rec) != keylen
 	    || rec_data_length(rec) != datalen
 	    || rec_extra_padding(rec) != actuallen - (keylen + datalen)) {
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-			 "Could not encode k=%llu,d=%llu,a=%llu",
-			 (long long)keylen, (long long)datalen,
-			 (long long)actuallen);
-		return -1;
+		return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+				  "Could not encode k=%llu,d=%llu,a=%llu",
+				  (long long)keylen, (long long)datalen,
+				  (long long)actuallen);
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
 /* Expand the database. */
-static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
+static enum TDB_ERROR tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 {
 	uint64_t old_size;
 	tdb_len_t wanted;
@@ -597,9 +653,8 @@ static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 	/* Need to hold a hash lock to expand DB: transactions rely on it. */
 	if (!(tdb->flags & TDB_NOLOCK)
 	    && !tdb->allrecord_lock.count && !tdb_has_hash_locks(tdb)) {
-		tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
-			   "tdb_expand: must hold lock during expand");
-		return -1;
+		return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
+				  "tdb_expand: must hold lock during expand");
 	}
 
 	/* always make room for at least 100 more records, and at
@@ -613,8 +668,7 @@ static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 	/* Only one person can expand file at a time. */
 	ecode = tdb_lock_expand(tdb, F_WRLCK);
 	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		return -1;
+		return ecode;
 	}
 
 	/* Someone else may have expanded the file, so retry. */
@@ -622,12 +676,13 @@ static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 	tdb->methods->oob(tdb, tdb->map_size + 1, true);
 	if (tdb->map_size != old_size) {
 		tdb_unlock_expand(tdb, F_WRLCK);
-		return 0;
+		return TDB_SUCCESS;
 	}
 
-	if (tdb->methods->expand_file(tdb, wanted) == -1) {
+	ecode = tdb->methods->expand_file(tdb, wanted);
+	if (ecode != TDB_SUCCESS) {
 		tdb_unlock_expand(tdb, F_WRLCK);
-		return -1;
+		return ecode;
 	}
 
 	/* We need to drop this lock before adding free record. */
@@ -647,12 +702,15 @@ tdb_off_t alloc(struct tdb_context *tdb, size_t keylen, size_t datalen,
 	assert(!tdb->direct_access);
 
 	for (;;) {
+		enum TDB_ERROR ecode;
 		off = get_free(tdb, keylen, datalen, growing, magic, hash);
 		if (likely(off != 0))
 			break;
 
-		if (tdb_expand(tdb, adjust_size(keylen, datalen)))
-			return TDB_OFF_ERR;
+		ecode = tdb_expand(tdb, adjust_size(keylen, datalen));
+		if (ecode != TDB_SUCCESS) {
+			return ecode;
+		}
 	}
 
 	return off;