X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb2%2Ftdb.c;h=8aceeeb9446b64193f155fa376bba823f3483514;hp=61791c9d5b5ca8af9ef22a1f88e07ce8f8bbafc7;hb=ecec5bef6776fb9d44bdf479b7efbff0040b2b38;hpb=dbf1ac48c3a1f5147dfcd457a7847a03de26a6c7

diff --git a/ccan/tdb2/tdb.c b/ccan/tdb2/tdb.c
index 61791c9d..8aceeeb9 100644
--- a/ccan/tdb2/tdb.c
+++ b/ccan/tdb2/tdb.c
@@ -236,12 +236,24 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 	tdb_io_init(tdb);
 	tdb_lock_init(tdb);
 
-	/* FIXME */
-	if (attr) {
-		tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
-			 "tdb_open: attributes not yet supported\n");
-		errno = EINVAL;
-		goto fail;
+	while (attr) {
+		switch (attr->base.attr) {
+		case TDB_ATTRIBUTE_LOG:
+			tdb->log = attr->log.log_fn;
+			tdb->log_priv = attr->log.log_private;
+			break;
+		case TDB_ATTRIBUTE_HASH:
+			tdb->khash = attr->hash.hash_fn;
+			tdb->hash_priv = attr->hash.hash_private;
+			break;
+		default:
+			tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
+				 "tdb_open: unknown attribute type %u\n",
+				 attr->base.attr);
+			errno = EINVAL;
+			goto fail;
+		}
+		attr = attr->base.next;
 	}
 
 	if ((open_flags & O_ACCMODE) == O_WRONLY) {
@@ -268,6 +280,8 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 		}
 		TEST_IT(tdb->flags & TDB_CONVERT);
 		tdb_convert(tdb, &tdb->header, sizeof(tdb->header));
+		/* Zones don't matter for internal db. */
+		tdb->last_zone = 0;
 		return tdb;
 	}
 
@@ -400,6 +414,8 @@ static tdb_off_t entry_matches(struct tdb_context *tdb,
 	uint64_t keylen;
 	const unsigned char *rkey;
 
+	list &= ((1ULL << tdb->header.v.hash_bits) - 1);
+
 	off = tdb_read_off(tdb, tdb->header.v.hash_off
 			   + list * sizeof(tdb_off_t));
 	if (off == 0 || off == TDB_OFF_ERR)
@@ -425,7 +441,7 @@ static tdb_off_t entry_matches(struct tdb_context *tdb,
 	if (keylen != key->dsize)
 		return TDB_OFF_ERR;
 
-	rkey = tdb_access_read(tdb, off + sizeof(*rec), keylen);
+	rkey = tdb_access_read(tdb, off + sizeof(*rec), keylen, false);
 	if (!rkey)
 		return TDB_OFF_ERR;
 	if (memcmp(rkey, key->dptr, keylen) != 0)
@@ -435,7 +451,7 @@ static tdb_off_t entry_matches(struct tdb_context *tdb,
 }
 
 /* FIXME: Optimize? */
-static void unlock_range(struct tdb_context *tdb,
+static void unlock_lists(struct tdb_context *tdb,
 			 tdb_off_t list, tdb_len_t num,
 			 int ltype)
 {
@@ -446,15 +462,16 @@ static void unlock_range(struct tdb_context *tdb,
 }
 
 /* FIXME: Optimize? */
-static int lock_range(struct tdb_context *tdb,
+static int lock_lists(struct tdb_context *tdb,
 		      tdb_off_t list, tdb_len_t num,
 		      int ltype)
 {
 	tdb_off_t i;
 
 	for (i = list; i < list + num; i++) {
-		if (tdb_lock_list(tdb, i, ltype, TDB_LOCK_WAIT) != 0) {
-			unlock_range(tdb, list, i - list, ltype);
+		if (tdb_lock_list(tdb, i, ltype, TDB_LOCK_WAIT)
+		    == TDB_OFF_ERR) {
+			unlock_lists(tdb, list, i - list, ltype);
 			return -1;
 		}
 	}
@@ -467,7 +484,7 @@ static int lock_range(struct tdb_context *tdb,
 static tdb_len_t relock_hash_to_zero(struct tdb_context *tdb,
 				     tdb_off_t start, int ltype)
 {
-	tdb_len_t num, len, pre_locks;
+	tdb_len_t num, len;
 
 again:
 	num = 1ULL << tdb->header.v.hash_bits;
@@ -475,39 +492,45 @@ again:
 	if (unlikely(len == num - start)) {
 		/* We hit the end of the hash range.  Drop lock: we have
 		   to lock start of hash first. */
+		tdb_len_t pre_locks;
+
 		tdb_unlock_list(tdb, start, ltype);
+
 		/* Grab something, so header is stable. */
 		if (tdb_lock_list(tdb, 0, ltype, TDB_LOCK_WAIT))
 			return TDB_OFF_ERR;
-		len = tdb_find_zero_off(tdb, hash_off(tdb, 0), num);
-		if (lock_range(tdb, 1, len, ltype) == -1) {
+		pre_locks = tdb_find_zero_off(tdb, hash_off(tdb, 0), num);
+		/* We want to lock the zero entry as well. */
+		pre_locks++;
+		if (lock_lists(tdb, 1, pre_locks - 1, ltype) == -1) {
 			tdb_unlock_list(tdb, 0, ltype);
 			return TDB_OFF_ERR;
 		}
-		pre_locks = len;
-		len = num - start;
+
+		/* Now lock later ones. */
+		if (unlikely(lock_lists(tdb, start, len, ltype) == -1)) {
+			unlock_lists(tdb, 0, pre_locks, ltype);
+			return TDB_OFF_ERR;
+		}
+		len += pre_locks;
 	} else {
-		/* We already have lock on start. */
-		start++;
-		pre_locks = 0;
-	}
-	if (unlikely(lock_range(tdb, start, len, ltype) == -1)) {
-		if (pre_locks)
-			unlock_range(tdb, 0, pre_locks, ltype);
-		else
+		/* We want to lock the zero entry as well. */
+		len++;
+		/* But we already have lock on start. */
+		if (unlikely(lock_lists(tdb, start+1, len-1, ltype) == -1)) {
 			tdb_unlock_list(tdb, start, ltype);
-		return TDB_OFF_ERR;
+			return TDB_OFF_ERR;
+		}
 	}
 
 	/* Now, did we lose the race, and it's not zero any more? */
-	if (unlikely(tdb_read_off(tdb, hash_off(tdb, pre_locks + len)) != 0)) {
-		unlock_range(tdb, 0, pre_locks, ltype);
+	if (unlikely(tdb_read_off(tdb, hash_off(tdb, start + len - 1)) != 0)) {
 		/* Leave the start locked, as expected. */
-		unlock_range(tdb, start + 1, len - 1, ltype);
+		unlock_lists(tdb, start + 1, len - 1, ltype);
 		goto again;
 	}
 
-	return pre_locks + len;
+	return len;
 }
 
 /* FIXME: modify, don't rewrite! */
@@ -518,9 +541,9 @@ static int update_rec_hdr(struct tdb_context *tdb,
 			  struct tdb_used_record *rec,
 			  uint64_t h)
 {
-	uint64_t room = rec_data_length(rec) + rec_extra_padding(rec);
+	uint64_t dataroom = rec_data_length(rec) + rec_extra_padding(rec);
 
-	if (set_header(tdb, rec, keylen, datalen, room - datalen, h))
+	if (set_header(tdb, rec, keylen, datalen, keylen + dataroom, h))
 		return -1;
 
 	return tdb_write_convert(tdb, off, rec, sizeof(*rec));
@@ -529,7 +552,8 @@ static int update_rec_hdr(struct tdb_context *tdb,
 /* If we fail, others will try after us. */
 static void enlarge_hash(struct tdb_context *tdb)
 {
-	tdb_off_t newoff, i;
+	tdb_off_t newoff, oldoff, i;
+	tdb_len_t hlen;
 	uint64_t h, num = 1ULL << tdb->header.v.hash_bits;
 	struct tdb_used_record pad, *r;
 
@@ -541,98 +565,137 @@ static void enlarge_hash(struct tdb_context *tdb)
 	if ((1ULL << tdb->header.v.hash_bits) != num)
 		goto unlock;
 
-	newoff = alloc(tdb, 0, num * 2, 0, false);
+	/* Allocate our new array. */
+	hlen = num * sizeof(tdb_off_t) * 2;
+	newoff = alloc(tdb, 0, hlen, 0, false);
 	if (unlikely(newoff == TDB_OFF_ERR))
 		goto unlock;
 	if (unlikely(newoff == 0)) {
-		if (tdb_expand(tdb, 0, num * 2, false) == -1)
+		if (tdb_expand(tdb, 0, hlen, false) == -1)
 			goto unlock;
-		newoff = alloc(tdb, 0, num * 2, 0, false);
+		newoff = alloc(tdb, 0, hlen, 0, false);
 		if (newoff == TDB_OFF_ERR || newoff == 0)
 			goto unlock;
 	}
+	/* Step over record header! */
+	newoff += sizeof(struct tdb_used_record);
+
+	/* Starts all zero. */
+	if (zero_out(tdb, newoff, hlen) == -1)
+		goto unlock;
 
 	/* FIXME: If the space before is empty, we know this is in its ideal
-	 * location.  We can steal a bit from the pointer to avoid rehash. */
-	for (i = tdb_find_nonzero_off(tdb, tdb->header.v.hash_off, num);
+	 * location.  Or steal a bit from the pointer to avoid rehash. */
+	for (i = tdb_find_nonzero_off(tdb, hash_off(tdb, 0), num);
 	     i < num;
-	     i += tdb_find_nonzero_off(tdb, tdb->header.v.hash_off
-				       + i*sizeof(tdb_off_t), num - i)) {
+	     i += tdb_find_nonzero_off(tdb, hash_off(tdb, i), num - i)) {
 		tdb_off_t off;
-		off = tdb_read_off(tdb, tdb->header.v.hash_off
-				   + i*sizeof(tdb_off_t));
+		off = tdb_read_off(tdb, hash_off(tdb, i));
 		if (unlikely(off == TDB_OFF_ERR))
 			goto unlock;
 		if (unlikely(!off)) {
 			tdb->ecode = TDB_ERR_CORRUPT;
 			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
-				 "find_bucket_and_lock: zero hash bucket!\n");
+				 "enlarge_hash: zero hash bucket!\n");
 			goto unlock;
 		}
-		h = hash_record(tdb, off);
+
+		/* Find next empty hash slot. */
+		for (h = hash_record(tdb, off);
+		     tdb_read_off(tdb, newoff + (h & ((num * 2)-1))
+				  * sizeof(tdb_off_t)) != 0;
+		     h++);
+
 		/* FIXME: Encode extra hash bits! */
-		if (tdb_write_off(tdb, newoff
-				  + (h & ((num * 2) - 1)) * sizeof(uint64_t),
-				  off) == -1)
+		if (tdb_write_off(tdb, newoff + (h & ((num * 2)-1))
+				  * sizeof(tdb_off_t), off) == -1)
 			goto unlock;
+		i++;
 	}
 
 	/* Free up old hash. */
-	r = tdb_get(tdb, tdb->header.v.hash_off, &pad, sizeof(*r));
+	oldoff = tdb->header.v.hash_off - sizeof(*r);
+	r = tdb_get(tdb, oldoff, &pad, sizeof(*r));
 	if (!r)
 		goto unlock;
-	add_free_record(tdb, tdb->header.v.hash_off,
-			rec_data_length(r) + rec_extra_padding(r));
+	add_free_record(tdb, oldoff,
+			sizeof(*r)+rec_data_length(r)+rec_extra_padding(r));
 
 	/* Now we write the modified header. */
-	tdb->header.v.generation++;
 	tdb->header.v.hash_bits++;
 	tdb->header.v.hash_off = newoff;
-	tdb_write_convert(tdb, offsetof(struct tdb_header, v),
-			  &tdb->header.v, sizeof(tdb->header.v));
+	write_header(tdb);
 unlock:
 	tdb_allrecord_unlock(tdb, F_WRLCK);
 }
 
+/* This is the core routine which searches the hashtable for an entry.
+ * On error, no locks are held and TDB_OFF_ERR is returned.
+ * Otherwise, *num_locks locks of type ltype from *start_lock are held.
+ * The bucket where the entry is (or would be) is in *bucket.
+ * If not found, the return value is 0.
+ * If found, the return value is the offset, and *rec is the record. */
+static tdb_off_t find_and_lock(struct tdb_context *tdb,
+			       struct tdb_data key,
+			       uint64_t h,
+			       int ltype,
+			       tdb_off_t *start_lock,
+			       tdb_len_t *num_locks,
+			       tdb_off_t *bucket,
+			       struct tdb_used_record *rec)
+{
+	tdb_off_t off;
+
+	/* FIXME: can we avoid locks for some fast paths? */
+	*start_lock = tdb_lock_list(tdb, h, ltype, TDB_LOCK_WAIT);
+	if (*start_lock == TDB_OFF_ERR)
+		return TDB_OFF_ERR;
+
+	/* Fast path. */
+	off = entry_matches(tdb, *start_lock, h, &key, rec);
+	if (likely(off != TDB_OFF_ERR)) {
+		*bucket = *start_lock;
+		*num_locks = 1;
+		return off;
+	}
+
+	/* Slow path, need to grab more locks and search. */
+
+	/* Warning: this may drop the lock on *bucket! */
+	*num_locks = relock_hash_to_zero(tdb, *start_lock, ltype);
+	if (*num_locks == TDB_OFF_ERR)
+		return TDB_OFF_ERR;
+
+	for (*bucket = *start_lock;
+	     *bucket < *start_lock + *num_locks;
+	     (*bucket)++) {
+		off = entry_matches(tdb, *bucket, h, &key, rec);
+		/* Empty entry or we found it? */
+		if (off == 0 || off != TDB_OFF_ERR)
+			return off;
+	}
+
+	/* We didn't find a zero entry?  Something went badly wrong... */
+	unlock_lists(tdb, *start_lock, *start_lock + *num_locks, ltype);
+	tdb->ecode = TDB_ERR_CORRUPT;
+	tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+		 "find_and_lock: expected to find an empty hash bucket!\n");
+	return TDB_OFF_ERR;
+}
+
 int tdb_store(struct tdb_context *tdb,
 	      struct tdb_data key, struct tdb_data dbuf, int flag)
 {
-	tdb_off_t new_off, off, old_bucket, start, num_locks = 1;
+	tdb_off_t new_off, off, bucket, start, num;
 	struct tdb_used_record rec;
 	uint64_t h;
 	bool growing = false;
 
 	h = tdb_hash(tdb, key.dptr, key.dsize);
-
-	/* FIXME: can we avoid locks for some fast paths? */
-	start = tdb_lock_list(tdb, h, F_WRLCK, TDB_LOCK_WAIT);
-	if (start == TDB_OFF_ERR)
+	off = find_and_lock(tdb, key, h, F_WRLCK, &start, &num, &bucket, &rec);
+	if (unlikely(off == TDB_OFF_ERR))
 		return -1;
 
-	/* Fast path. */
-	old_bucket = start;
-	off = entry_matches(tdb, start, h, &key, &rec);
-	if (unlikely(off == TDB_OFF_ERR)) {
-		/* Slow path, need to grab more locks and search. */
-		tdb_off_t i;
-
-		/* Warning: this may drop the lock!  Does that on error. */
-		num_locks = relock_hash_to_zero(tdb, start, F_WRLCK);
-		if (num_locks == TDB_OFF_ERR)
-			return -1;
-
-		for (i = start; i < start + num_locks; i++) {
-			off = entry_matches(tdb, i, h, &key, &rec);
-			/* Empty entry or we found it? */
-			if (off == 0 || off != TDB_OFF_ERR) {
-				old_bucket = i;
-				break;
-			}
-		}
-		if (i == start + num_locks)
-			off = 0;
-	}
-
 	/* Now we have lock on this hash bucket. */
 	if (flag == TDB_INSERT) {
 		if (off) {
@@ -667,7 +730,7 @@ int tdb_store(struct tdb_context *tdb,
 	/* Allocate a new record. */
 	new_off = alloc(tdb, key.dsize, dbuf.dsize, h, growing);
 	if (new_off == 0) {
-		unlock_range(tdb, start, num_locks, F_WRLCK);
+		unlock_lists(tdb, start, num, F_WRLCK);
 		/* Expand, then try again... */
 		if (tdb_expand(tdb, key.dsize, dbuf.dsize, growing) == -1)
 			return -1;
@@ -682,11 +745,11 @@ int tdb_store(struct tdb_context *tdb,
 				+ rec_extra_padding(&rec));
 	}
 
-write:
 	/* FIXME: Encode extra hash bits! */
-	if (tdb_write_off(tdb, hash_off(tdb, old_bucket), new_off) == -1)
+	if (tdb_write_off(tdb, hash_off(tdb, bucket), new_off) == -1)
 		goto fail;
 
+write:
 	off = new_off + sizeof(struct tdb_used_record);
 	if (tdb->methods->write(tdb, off, key.dptr, key.dsize) == -1)
 		goto fail;
@@ -695,65 +758,42 @@ write:
 		goto fail;
 
 	/* FIXME: tdb_increment_seqnum(tdb); */
-	unlock_range(tdb, start, num_locks, F_WRLCK);
+	unlock_lists(tdb, start, num, F_WRLCK);
 
 	/* FIXME: by simple simulation, this approximated 60% full.
 	 * Check in real case! */
-	if (unlikely(num_locks > 4 * tdb->header.v.hash_bits - 31))
+	if (unlikely(num > 4 * tdb->header.v.hash_bits - 30))
 		enlarge_hash(tdb);
 
 	return 0;
 
 fail:
-	unlock_range(tdb, start, num_locks, F_WRLCK);
+	unlock_lists(tdb, start, num, F_WRLCK);
 	return -1;
 }
 
 struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
 {
-	tdb_off_t off, start, num_locks = 1;
+	tdb_off_t off, start, num, bucket;
 	struct tdb_used_record rec;
 	uint64_t h;
 	struct tdb_data ret;
 
 	h = tdb_hash(tdb, key.dptr, key.dsize);
-
-	/* FIXME: can we avoid locks for some fast paths? */
-	start = tdb_lock_list(tdb, h, F_RDLCK, TDB_LOCK_WAIT);
-	if (start == TDB_OFF_ERR)
+	off = find_and_lock(tdb, key, h, F_RDLCK, &start, &num, &bucket, &rec);
+	if (unlikely(off == TDB_OFF_ERR))
 		return tdb_null;
 
-	/* Fast path. */
-	off = entry_matches(tdb, start, h, &key, &rec);
-	if (unlikely(off == TDB_OFF_ERR)) {
-		/* Slow path, need to grab more locks and search. */
-		tdb_off_t i;
-
-		/* Warning: this may drop the lock!  Does that on error. */
-		num_locks = relock_hash_to_zero(tdb, start, F_RDLCK);
-		if (num_locks == TDB_OFF_ERR)
-			return tdb_null;
-
-		for (i = start; i < start + num_locks; i++) {
-			off = entry_matches(tdb, i, h, &key, &rec);
-			/* Empty entry or we found it? */
-			if (off == 0 || off != TDB_OFF_ERR)
-				break;
-		}
-		if (i == start + num_locks)
-			off = 0;
-	}
-
 	if (!off) {
-		unlock_range(tdb, start, num_locks, F_RDLCK);
 		tdb->ecode = TDB_ERR_NOEXIST;
-		return tdb_null;
+		ret = tdb_null;
+	} else {
+		ret.dsize = rec_data_length(&rec);
+		ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
+					  ret.dsize);
 	}
 
-	ret.dsize = rec_data_length(&rec);
-	ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
-				  ret.dsize);
-	unlock_range(tdb, start, num_locks, F_RDLCK);
+	unlock_lists(tdb, start, num, F_RDLCK);
 	return ret;
 }
 
@@ -784,66 +824,28 @@ static int hash_add(struct tdb_context *tdb, uint64_t h, tdb_off_t off)
 
 int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 {
-	tdb_off_t i, old_bucket, off, start, num_locks = 1;
+	tdb_off_t i, bucket, off, start, num;
 	struct tdb_used_record rec;
 	uint64_t h;
 
 	h = tdb_hash(tdb, key.dptr, key.dsize);
-
-	/* FIXME: can we avoid locks for some fast paths? */
-	start = tdb_lock_list(tdb, h, F_WRLCK, TDB_LOCK_WAIT);
-	if (start == TDB_OFF_ERR)
+	off = find_and_lock(tdb, key, h, F_WRLCK, &start, &num, &bucket, &rec);
+	if (unlikely(off == TDB_OFF_ERR))
 		return -1;
 
-	/* Fast path. */
-	old_bucket = start;
-	off = entry_matches(tdb, start, h, &key, &rec);
-	if (off && off != TDB_OFF_ERR) {
-		/* We can only really fastpath delete if next bucket
-		 * is 0.  Note that we haven't locked it, but our lock
-		 * on this bucket stops anyone overflowing into it
-		 * while we look. */
-		if (tdb_read_off(tdb, hash_off(tdb, h+1)) == 0)
-			goto delete;
-		/* Slow path. */
-		off = TDB_OFF_ERR;
-	}
-
-	if (unlikely(off == TDB_OFF_ERR)) {
-		/* Slow path, need to grab more locks and search. */
-		tdb_off_t i;
-
-		/* Warning: this may drop the lock!  Does that on error. */
-		num_locks = relock_hash_to_zero(tdb, start, F_WRLCK);
-		if (num_locks == TDB_OFF_ERR)
-			return -1;
-
-		for (i = start; i < start + num_locks; i++) {
-			off = entry_matches(tdb, i, h, &key, &rec);
-			/* Empty entry or we found it? */
-			if (off == 0 || off != TDB_OFF_ERR) {
-				old_bucket = i;
-				break;
-			}
-		}
-		if (i == start + num_locks)
-			off = 0;
-	}
-
 	if (!off) {
-		unlock_range(tdb, start, num_locks, F_WRLCK);
+		unlock_lists(tdb, start, num, F_WRLCK);
 		tdb->ecode = TDB_ERR_NOEXIST;
 		return -1;
 	}
 
-delete:
 	/* This actually unlinks it. */
-	if (tdb_write_off(tdb, hash_off(tdb, old_bucket), 0) == -1)
+	if (tdb_write_off(tdb, hash_off(tdb, bucket), 0) == -1)
 		goto unlock_err;
 
 	/* Rehash anything following. */
-	for (i = hash_off(tdb, old_bucket+1);
-	     i != hash_off(tdb, h + num_locks);
+	for (i = hash_off(tdb, bucket+1);
+	     i != hash_off(tdb, h + num - 1);
 	     i += sizeof(tdb_off_t)) {
 		tdb_off_t off2;
 		uint64_t h2;
@@ -852,6 +854,10 @@ delete:
 		if (unlikely(off2 == TDB_OFF_ERR))
 			goto unlock_err;
 
+		/* This can happen if we raced. */
+		if (unlikely(off2 == 0))
+			break;
+
 		/* Maybe use a bit to indicate it is in ideal place? */
 		h2 = hash_record(tdb, off2);
 		/* Is it happy where it is? */
@@ -875,11 +881,11 @@ delete:
 			    + rec_extra_padding(&rec)) != 0)
 		goto unlock_err;
 
-	unlock_range(tdb, start, num_locks, F_WRLCK);
+	unlock_lists(tdb, start, num, F_WRLCK);
 	return 0;
 
 unlock_err:
-	unlock_range(tdb, start, num_locks, F_WRLCK);
+	unlock_lists(tdb, start, num, F_WRLCK);
 	return -1;
 }