#include "private.h"
#include <ccan/tdb2/tdb2.h>
#include <ccan/hash/hash.h>
+#include <ccan/build_assert/build_assert.h>
#include <ccan/likely/likely.h>
#include <assert.h>
/* We do a lot of work assuming our copy of the header volatile area
* is uptodate, and usually it is. However, once we grab a lock, we have to
* re-check it. */
-bool update_header(struct tdb_context *tdb)
+bool header_changed(struct tdb_context *tdb)
{
- struct tdb_header_volatile pad, *v;
+ uint64_t gen;
- if (tdb->header_uptodate) {
+ if (!(tdb->flags & TDB_NOLOCK) && tdb->header_uptodate) {
tdb->log(tdb, TDB_DEBUG_WARNING, tdb->log_priv,
"warning: header uptodate already\n");
}
/* We could get a partial update if we're not holding any locks. */
- assert(tdb_has_locks(tdb));
+ assert((tdb->flags & TDB_NOLOCK) || tdb_has_locks(tdb));
- v = tdb_get(tdb, offsetof(struct tdb_header, v), &pad, sizeof(*v));
- if (!v) {
- /* On failure, imply we updated header so they retry. */
- return true;
- }
tdb->header_uptodate = true;
- if (likely(memcmp(&tdb->header.v, v, sizeof(*v)) == 0)) {
- return false;
+ gen = tdb_read_off(tdb, offsetof(struct tdb_header, v.generation));
+ if (unlikely(gen != tdb->header.v.generation)) {
+ tdb_read_convert(tdb, offsetof(struct tdb_header, v),
+ &tdb->header.v, sizeof(tdb->header.v));
+ return true;
}
- tdb->header.v = *v;
- return true;
+ return false;
+}
+
+int write_header(struct tdb_context *tdb)
+{
+ assert(tdb_read_off(tdb, offsetof(struct tdb_header, v.generation))
+ == tdb->header.v.generation);
+ tdb->header.v.generation++;
+ return tdb_write_convert(tdb, offsetof(struct tdb_header, v),
+ &tdb->header.v, sizeof(tdb->header.v));
}
static uint64_t jenkins_hash(const void *key, size_t length, uint64_t seed,
void *arg)
{
- return hash64_any(key, length, seed);
+ return hash64_stable((const unsigned char *)key, length, seed);
}
uint64_t tdb_hash(struct tdb_context *tdb, const void *ptr, size_t len)
fd = open("/dev/urandom", O_RDONLY);
if (fd >= 0) {
- if (read(fd, &ret, sizeof(ret)) == sizeof(ret)) {
+ if (tdb_read_all(fd, &ret, sizeof(ret))) {
tdb->log(tdb, TDB_DEBUG_TRACE, tdb->log_priv,
"tdb_open: random from /dev/urandom\n");
close(fd);
{
/* We make it up in memory, then write it out if not internal */
struct new_database newdb;
+ unsigned int magic_off = offsetof(struct tdb_header, magic_food);
/* Fill in the header */
newdb.hdr.version = TDB_VERSION;
sizeof(newdb.hdr.hash_test),
newdb.hdr.hash_seed,
tdb->hash_priv);
-
+ memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved));
newdb.hdr.v.generation = 0;
+ /* The initial zone must cover the initial database size! */
+ BUILD_ASSERT((1ULL << INITIAL_ZONE_BITS) >= sizeof(newdb));
+
/* Free array has 1 zone, 10 buckets. All buckets empty. */
newdb.hdr.v.num_zones = 1;
newdb.hdr.v.zone_bits = INITIAL_ZONE_BITS;
sizeof(newdb.hash), sizeof(newdb.hash), 0);
memset(newdb.hash, 0, sizeof(newdb.hash));
+ /* Magic food */
+ memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
+ strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
+
+ /* This creates an endian-converted database, as if read from disk */
+ tdb_convert(tdb,
+ (char *)&newdb.hdr + magic_off,
+ sizeof(newdb) - magic_off);
+
+ tdb->header = newdb.hdr;
+
if (tdb->flags & TDB_INTERNAL) {
tdb->map_size = sizeof(newdb);
tdb->map_ptr = malloc(tdb->map_size);
return -1;
}
memcpy(tdb->map_ptr, &newdb, tdb->map_size);
- tdb->header = newdb.hdr;
- /* Convert the `ondisk' version if asked. */
- tdb_convert(tdb, tdb->map_ptr, sizeof(newdb));
return 0;
}
if (lseek(tdb->fd, 0, SEEK_SET) == -1)
if (ftruncate(tdb->fd, 0) == -1)
return -1;
- /* This creates an endian-converted header, as if read from disk */
- tdb->header = newdb.hdr;
- tdb_convert(tdb, &tdb->header, sizeof(tdb->header));
-
- /* Don't endian-convert the magic food! */
- memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
- strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
-
if (!tdb_pwrite_all(tdb->fd, &newdb, sizeof(newdb), 0)) {
tdb->ecode = TDB_ERR_IO;
return -1;
uint64_t hash_test;
unsigned v;
- if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {
+ tdb = malloc(sizeof(*tdb));
+ if (!tdb) {
/* Can't log this */
errno = ENOMEM;
goto fail;
}
- tdb->fd = -1;
tdb->name = NULL;
tdb->map_ptr = NULL;
+ tdb->fd = -1;
+ /* map_size will be set below. */
+ tdb->ecode = TDB_SUCCESS;
+ /* header will be read in below. */
+ tdb->header_uptodate = false;
tdb->flags = tdb_flags;
tdb->log = null_log_fn;
tdb->log_priv = NULL;
tdb->khash = jenkins_hash;
tdb->hash_priv = NULL;
+ tdb->transaction = NULL;
+ /* last_zone will be set below. */
+ 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) {
}
if ((open_flags & O_ACCMODE) == O_RDONLY) {
- tdb->read_only = 1;
+ tdb->read_only = true;
/* read only databases don't do locking */
tdb->flags |= TDB_NOLOCK;
- }
+ } else
+ tdb->read_only = false;
- /* internal databases don't mmap or lock */
+ /* internal databases don't need any of the rest. */
if (tdb->flags & TDB_INTERNAL) {
tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
if (tdb_new_database(tdb) != 0) {
goto fail;
}
TEST_IT(tdb->flags & TDB_CONVERT);
- goto internal;
+ tdb_convert(tdb, &tdb->header, sizeof(tdb->header));
+ /* Zones don't matter for internal db. */
+ tdb->last_zone = 0;
+ return tdb;
}
if ((tdb->fd = open(name, open_flags, mode)) == -1) {
goto fail; /* errno set by tdb_brlock */
}
- errno = 0;
- if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
+ if (!tdb_pread_all(tdb->fd, &tdb->header, sizeof(tdb->header), 0)
|| strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0) {
if (!(open_flags & O_CREAT) || tdb_new_database(tdb) == -1) {
if (errno == 0) {
tdb->map_size = st.st_size;
tdb->device = st.st_dev;
tdb->inode = st.st_ino;
- tdb_io_init(tdb);
tdb_mmap(tdb);
-
- internal:
- /* Internal (memory-only) databases skip all the code above to
- * do with disk files, and resume here by releasing their
- * open lock and hooking into the active list. */
tdb_unlock_open(tdb);
- tdb->last_zone = random_free_zone(tdb);
+ tdb_zone_init(tdb);
+
tdb->next = tdbs;
tdbs = tdb;
return tdb;
return NULL;
}
-static int tdb_key_compare(TDB_DATA key, TDB_DATA data, void *private_data)
-{
- return memcmp(data.dptr, key.dptr, data.dsize) == 0;
-}
-
-static void unlock_lists(struct tdb_context *tdb,
- uint64_t start, uint64_t end, int ltype)
+tdb_off_t hash_off(struct tdb_context *tdb, uint64_t list)
{
- do {
- tdb_unlock_list(tdb, start, ltype);
- start = (start + ((1ULL << tdb->header.v.hash_bits) - 1))
- & ((1ULL << tdb->header.v.hash_bits) - 1);
- } while (start != end);
+ return tdb->header.v.hash_off
+ + ((list & ((1ULL << tdb->header.v.hash_bits) - 1))
+ * sizeof(tdb_off_t));
}
-/* FIXME: Return header copy? */
-/* Returns -1 or offset of entry (0 if not found).
- * Locks hash entried from *start to *end (where the entry was found). */
-static tdb_off_t find_bucket_and_lock(struct tdb_context *tdb,
- const struct tdb_data *key,
- uint64_t hash,
- uint64_t *start,
- uint64_t *end,
- uint64_t *room,
- int ltype)
+/* Returns 0 if the entry is a zero (definitely not a match).
+ * Returns a valid entry offset if it's a match. Fills in rec.
+ * Otherwise returns TDB_OFF_ERR: keep searching. */
+static tdb_off_t entry_matches(struct tdb_context *tdb,
+ uint64_t list,
+ uint64_t hash,
+ const struct tdb_data *key,
+ struct tdb_used_record *rec)
{
- uint64_t hextra;
tdb_off_t off;
+ uint64_t keylen;
+ const unsigned char *rkey;
- /* hash_bits might be out of date... */
-again:
- *start = *end = hash & ((1ULL << tdb->header.v.hash_bits) - 1);
- hextra = hash >> tdb->header.v.hash_bits;
+ list &= ((1ULL << tdb->header.v.hash_bits) - 1);
- /* FIXME: can we avoid locks for some fast paths? */
- if (tdb_lock_list(tdb, *end, ltype, TDB_LOCK_WAIT) == -1)
+ off = tdb_read_off(tdb, tdb->header.v.hash_off
+ + list * sizeof(tdb_off_t));
+ if (off == 0 || off == TDB_OFF_ERR)
+ return off;
+
+#if 0 /* FIXME: Check other bits. */
+ unsigned int bits, bitmask, hoffextra;
+ /* Bottom three bits show how many extra hash bits. */
+ bits = (off & ((1 << TDB_EXTRA_HASHBITS_NUM) - 1)) + 1;
+ bitmask = (1 << bits)-1;
+ hoffextra = ((off >> TDB_EXTRA_HASHBITS_NUM) & bitmask);
+ uint64_t hextra = hash >> tdb->header.v.hash_bits;
+ if ((hextra & bitmask) != hoffextra)
return TDB_OFF_ERR;
+ off &= ~...;
+#endif
- /* We only need to check this for first lock. */
- if (unlikely(update_header(tdb))) {
- tdb_unlock_list(tdb, *end, ltype);
- goto again;
- }
+ if (tdb_read_convert(tdb, off, rec, sizeof(*rec)) == -1)
+ return TDB_OFF_ERR;
- while ((off = tdb_read_off(tdb, tdb->header.v.hash_off
- + *end * sizeof(tdb_off_t)))
- != TDB_OFF_ERR) {
- struct tdb_used_record pad, *r;
- uint64_t keylen, next;
+ /* FIXME: check extra bits in header! */
+ keylen = rec_key_length(rec);
+ if (keylen != key->dsize)
+ return TDB_OFF_ERR;
- /* Didn't find it? */
- if (!off)
- return 0;
+ rkey = tdb_access_read(tdb, off + sizeof(*rec), keylen, false);
+ if (!rkey)
+ return TDB_OFF_ERR;
+ if (memcmp(rkey, key->dptr, keylen) != 0)
+ off = TDB_OFF_ERR;
+ tdb_access_release(tdb, rkey);
+ return off;
+}
-#if 0 /* FIXME: Check other bits. */
- unsigned int bits, bitmask, hoffextra;
- /* Bottom three bits show how many extra hash bits. */
- bits = (off & ((1 << TDB_EXTRA_HASHBITS_NUM) - 1)) + 1;
- bitmask = (1 << bits)-1;
- hoffextra = ((off >> TDB_EXTRA_HASHBITS_NUM) & bitmask);
- if ((hextra & bitmask) != hoffextra)
- goto lock_next;
-#endif
+/* FIXME: Optimize? */
+static void unlock_lists(struct tdb_context *tdb,
+ tdb_off_t list, tdb_len_t num,
+ int ltype)
+{
+ tdb_off_t i;
- r = tdb_get(tdb, off, &pad, sizeof(*r));
- if (!r)
- goto unlock_err;
+ for (i = list; i < list + num; i++)
+ tdb_unlock_list(tdb, i, ltype);
+}
- if (rec_magic(r) != TDB_MAGIC) {
- tdb->ecode = TDB_ERR_CORRUPT;
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "find_bucket_and_lock: bad magic 0x%llx"
- " at offset %llu!\n",
- (long long)rec_magic(r), (long long)off);
- goto unlock_err;
+/* FIXME: Optimize? */
+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)
+ == TDB_OFF_ERR) {
+ unlock_lists(tdb, list, i - list, ltype);
+ return -1;
}
+ }
+ return 0;
+}
- /* FIXME: check extra bits in header! */
- keylen = rec_key_length(r);
- if (keylen != key->dsize)
- goto lock_next;
-
- switch (tdb_parse_data(tdb, *key, off + sizeof(*r), key->dsize,
- tdb_key_compare, NULL)) {
- case 1:
- /* Match! */
- *room = rec_data_length(r) + rec_extra_padding(r);
- return off >> TDB_EXTRA_HASHBITS_NUM;
- case 0:
- break;
- default:
- goto unlock_err;
+/* We lock hashes up to the next empty offset. We already hold the
+ * lock on the start bucket, but we may need to release and re-grab
+ * it. If we fail, we hold no locks at all! */
+static tdb_len_t relock_hash_to_zero(struct tdb_context *tdb,
+ tdb_off_t start, int ltype)
+{
+ tdb_len_t num, len;
+
+again:
+ num = 1ULL << tdb->header.v.hash_bits;
+ len = tdb_find_zero_off(tdb, hash_off(tdb, start), num - start);
+ 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;
+ 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;
}
- lock_next:
- /* Lock next bucket. */
- /* FIXME: We can deadlock if this wraps! */
- next = (*end + 1) & ((1ULL << tdb->header.v.hash_bits) - 1);
- if (next == *start) {
- tdb->ecode = TDB_ERR_CORRUPT;
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "find_bucket_and_lock: full hash table!\n");
- goto unlock_err;
+ /* 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 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;
}
- if (tdb_lock_list(tdb, next, ltype, TDB_LOCK_WAIT) == -1)
- goto unlock_err;
- *end = next;
}
-unlock_err:
- TEST_IT(*end < *start);
- unlock_lists(tdb, *start, *end, ltype);
- 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, start + len - 1)) != 0)) {
+ /* Leave the start locked, as expected. */
+ unlock_lists(tdb, start + 1, len - 1, ltype);
+ goto again;
+ }
+
+ return len;
}
+/* FIXME: modify, don't rewrite! */
static int update_rec_hdr(struct tdb_context *tdb,
tdb_off_t off,
tdb_len_t keylen,
tdb_len_t datalen,
- tdb_len_t room,
+ struct tdb_used_record *rec,
uint64_t h)
{
- struct tdb_used_record 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));
+ return tdb_write_convert(tdb, off, rec, sizeof(*rec));
+}
+
+static int hash_add(struct tdb_context *tdb,
+ uint64_t hash, tdb_off_t off)
+{
+ tdb_off_t i, hoff, len, num;
+
+ /* Look for next space. */
+ i = (hash & ((1ULL << tdb->header.v.hash_bits) - 1));
+ len = (1ULL << tdb->header.v.hash_bits) - i;
+ num = tdb_find_zero_off(tdb, hash_off(tdb, i), len);
+
+ if (unlikely(num == len)) {
+ /* We wrapped. Look through start of hash table. */
+ i = 0;
+ hoff = hash_off(tdb, 0);
+ len = (1ULL << tdb->header.v.hash_bits);
+ num = tdb_find_zero_off(tdb, hoff, len);
+ if (num == len) {
+ tdb->ecode = TDB_ERR_CORRUPT;
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "hash_add: full hash table!\n");
+ return -1;
+ }
+ }
+ if (tdb_read_off(tdb, hash_off(tdb, i + num)) != 0) {
+ tdb->ecode = TDB_ERR_CORRUPT;
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "hash_add: overwriting hash table?\n");
+ return -1;
+ }
+
+ /* FIXME: Encode extra hash bits! */
+ return tdb_write_off(tdb, hash_off(tdb, i + num), off);
}
/* If we fail, others will try after us. */
static void enlarge_hash(struct tdb_context *tdb)
{
- tdb_off_t newoff, i;
- uint64_t h, num = 1ULL << tdb->header.v.hash_bits;
+ tdb_off_t newoff, oldoff, i;
+ tdb_len_t hlen;
+ uint64_t num = 1ULL << tdb->header.v.hash_bits;
struct tdb_used_record pad, *r;
+ unsigned int records = 0;
/* FIXME: We should do this without holding locks throughout. */
if (tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false) == -1)
return;
- if (unlikely(update_header(tdb))) {
- /* Someone else enlarged for us? Nothing to do. */
- if ((1ULL << tdb->header.v.hash_bits) != num)
- goto unlock;
- }
+ /* Someone else enlarged for us? Nothing to do. */
+ if ((1ULL << tdb->header.v.hash_bits) != num)
+ goto unlock;
- newoff = alloc(tdb, 0, num * 2, 0, false);
+again:
+ /* 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)
- goto unlock;
- newoff = alloc(tdb, 0, num * 2, 0, false);
- if (newoff == TDB_OFF_ERR || newoff == 0)
+ if (tdb_expand(tdb, 0, hlen, false) == -1)
goto unlock;
+ goto again;
}
+ /* Step over record header! */
+ newoff += sizeof(struct tdb_used_record);
+
+ /* Starts all zero. */
+ if (zero_out(tdb, newoff, hlen) == -1)
+ goto unlock;
+
+ /* Update header now so we can use normal routines. */
+ oldoff = tdb->header.v.hash_off;
+
+ tdb->header.v.hash_bits++;
+ tdb->header.v.hash_off = newoff;
/* 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);
- i < num;
- i += tdb_find_nonzero_off(tdb, tdb->header.v.hash_off
- + i*sizeof(tdb_off_t), num - i)) {
+ * location. Or steal a bit from the pointer to avoid rehash. */
+ for (i = 0; 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, oldoff + i * sizeof(tdb_off_t));
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");
- goto unlock;
- }
- h = hash_record(tdb, off);
- /* FIXME: Encode extra hash bits! */
- if (tdb_write_off(tdb, newoff
- + (h & ((num * 2) - 1)) * sizeof(uint64_t),
- off) == -1)
- goto unlock;
+ goto oldheader;
+ if (off && hash_add(tdb, hash_record(tdb, off), off) == -1)
+ goto oldheader;
+ if (off)
+ records++;
}
+ tdb->log(tdb, TDB_DEBUG_TRACE, tdb->log_priv,
+ "enlarge_hash: moved %u records from %llu buckets.\n",
+ records, (long long)num);
+
/* Free up old hash. */
- r = tdb_get(tdb, tdb->header.v.hash_off, &pad, sizeof(*r));
+ r = tdb_get(tdb, oldoff - sizeof(*r), &pad, sizeof(*r));
if (!r)
- goto unlock;
- add_free_record(tdb, tdb->header.v.hash_off,
- rec_data_length(r) + rec_extra_padding(r));
+ goto oldheader;
+ add_free_record(tdb, oldoff - sizeof(*r),
+ 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);
+ return;
+
+oldheader:
+ tdb->header.v.hash_bits--;
+ tdb->header.v.hash_off = oldoff;
+ goto unlock;
+}
+
+
+/* This is the slow version of the routine which searches the
+ * hashtable for an entry.
+ * We lock every hash bucket up to and including the next zero one.
+ */
+static tdb_off_t find_and_lock_slow(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)
+{
+ /* 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)++) {
+ tdb_off_t 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;
+}
+
+/* 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. */
+ return find_and_lock_slow(tdb, key, h, ltype, start_lock, num_locks,
+ bucket, rec);
+}
+
+/* Returns -1 on error, 0 on OK, 1 on "expand and retry." */
+static int replace_data(struct tdb_context *tdb,
+ uint64_t h, struct tdb_data key, struct tdb_data dbuf,
+ tdb_off_t bucket,
+ tdb_off_t old_off, tdb_len_t old_room,
+ bool growing)
+{
+ tdb_off_t new_off;
+
+ /* Allocate a new record. */
+ new_off = alloc(tdb, key.dsize, dbuf.dsize, h, growing);
+ if (unlikely(new_off == TDB_OFF_ERR))
+ return -1;
+
+ if (unlikely(new_off == 0))
+ return 1;
+
+ /* We didn't like the existing one: remove it. */
+ if (old_off)
+ add_free_record(tdb, old_off,
+ sizeof(struct tdb_used_record)
+ + key.dsize + old_room);
+
+ /* FIXME: Encode extra hash bits! */
+ if (tdb_write_off(tdb, hash_off(tdb, bucket), new_off) == -1)
+ return -1;
+
+ new_off += sizeof(struct tdb_used_record);
+ if (tdb->methods->write(tdb, new_off, key.dptr, key.dsize) == -1)
+ return -1;
+
+ new_off += key.dsize;
+ if (tdb->methods->write(tdb, new_off, dbuf.dptr, dbuf.dsize) == -1)
+ return -1;
+
+ /* FIXME: tdb_increment_seqnum(tdb); */
+ return 0;
}
int tdb_store(struct tdb_context *tdb,
struct tdb_data key, struct tdb_data dbuf, int flag)
{
- tdb_off_t new_off, off, start, end, room;
+ tdb_off_t off, bucket, start, num;
+ tdb_len_t old_room = 0;
+ struct tdb_used_record rec;
uint64_t h;
- bool growing = false;
+ int ret;
h = tdb_hash(tdb, key.dptr, key.dsize);
- off = find_bucket_and_lock(tdb, &key, h, &start, &end, &room, F_WRLCK);
- if (off == TDB_OFF_ERR)
+ off = find_and_lock(tdb, key, h, F_WRLCK, &start, &num, &bucket, &rec);
+ if (unlikely(off == TDB_OFF_ERR))
return -1;
/* Now we have lock on this hash bucket. */
}
} else {
if (off) {
- if (room >= key.dsize + dbuf.dsize) {
- new_off = off;
+ old_room = rec_data_length(&rec)
+ + rec_extra_padding(&rec);
+ if (old_room >= dbuf.dsize) {
+ /* Can modify in-place. Easy! */
if (update_rec_hdr(tdb, off,
key.dsize, dbuf.dsize,
- room, h))
+ &rec, h))
+ goto fail;
+ if (tdb->methods->write(tdb, off + sizeof(rec)
+ + key.dsize,
+ dbuf.dptr, dbuf.dsize))
goto fail;
- goto write;
+ unlock_lists(tdb, start, num, F_WRLCK);
+ return 0;
}
/* FIXME: See if right record is free? */
- /* Hint to allocator that we've realloced. */
- growing = true;
} else {
if (flag == TDB_MODIFY) {
/* if the record doesn't exist and we
}
}
- /* Allocate a new record. */
- new_off = alloc(tdb, key.dsize, dbuf.dsize, h, growing);
- if (new_off == 0) {
- unlock_lists(tdb, start, end, F_WRLCK);
+ /* If we didn't use the old record, this implies we're growing. */
+ ret = replace_data(tdb, h, key, dbuf, bucket, off, old_room, off != 0);
+ unlock_lists(tdb, start, num, F_WRLCK);
+
+ if (unlikely(ret == 1)) {
/* Expand, then try again... */
- if (tdb_expand(tdb, key.dsize, dbuf.dsize, growing) == -1)
+ if (tdb_expand(tdb, key.dsize, dbuf.dsize, off != 0) == -1)
return -1;
return tdb_store(tdb, key, dbuf, flag);
}
- /* We didn't like the existing one: remove it. */
+ /* FIXME: by simple simulation, this approximated 60% full.
+ * Check in real case! */
+ if (unlikely(num > 4 * tdb->header.v.hash_bits - 30))
+ enlarge_hash(tdb);
+
+ return ret;
+
+fail:
+ unlock_lists(tdb, start, num, F_WRLCK);
+ return -1;
+}
+
+int tdb_append(struct tdb_context *tdb,
+ struct tdb_data key, struct tdb_data dbuf)
+{
+ tdb_off_t off, bucket, start, num;
+ struct tdb_used_record rec;
+ tdb_len_t old_room = 0, old_dlen;
+ uint64_t h;
+ unsigned char *newdata;
+ struct tdb_data new_dbuf;
+ int ret;
+
+ h = tdb_hash(tdb, key.dptr, key.dsize);
+ off = find_and_lock(tdb, key, h, F_WRLCK, &start, &num, &bucket, &rec);
+ if (unlikely(off == TDB_OFF_ERR))
+ return -1;
+
if (off) {
- add_free_record(tdb, off, sizeof(struct tdb_used_record)
- + key.dsize + room);
- }
+ old_dlen = rec_data_length(&rec);
+ old_room = old_dlen + rec_extra_padding(&rec);
-write:
- off = tdb->header.v.hash_off + end * sizeof(tdb_off_t);
- /* FIXME: Encode extra hash bits! */
- if (tdb_write_off(tdb, off, new_off) == -1)
- goto fail;
+ /* Fast path: can append in place. */
+ if (rec_extra_padding(&rec) >= dbuf.dsize) {
+ if (update_rec_hdr(tdb, off, key.dsize,
+ old_dlen + dbuf.dsize, &rec, h))
+ goto fail;
- off = new_off + sizeof(struct tdb_used_record);
- if (tdb->methods->write(tdb, off, key.dptr, key.dsize) == -1)
- goto fail;
- off += key.dsize;
- if (tdb->methods->write(tdb, off, dbuf.dptr, dbuf.dsize) == -1)
- goto fail;
+ off += sizeof(rec) + key.dsize + old_dlen;
+ if (tdb->methods->write(tdb, off, dbuf.dptr,
+ dbuf.dsize) == -1)
+ goto fail;
- /* FIXME: tdb_increment_seqnum(tdb); */
- unlock_lists(tdb, start, end, F_WRLCK);
+ /* FIXME: tdb_increment_seqnum(tdb); */
+ unlock_lists(tdb, start, num, F_WRLCK);
+ return 0;
+ }
+ /* FIXME: Check right record free? */
+
+ /* Slow path. */
+ newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
+ if (!newdata) {
+ tdb->ecode = TDB_ERR_OOM;
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "tdb_append: cannot allocate %llu bytes!\n",
+ (long long)key.dsize + old_dlen + dbuf.dsize);
+ goto fail;
+ }
+ if (tdb->methods->read(tdb, off + sizeof(rec) + key.dsize,
+ newdata, old_dlen) != 0) {
+ free(newdata);
+ goto fail;
+ }
+ memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
+ new_dbuf.dptr = newdata;
+ new_dbuf.dsize = old_dlen + dbuf.dsize;
+ } else {
+ newdata = NULL;
+ new_dbuf = dbuf;
+ }
+
+ /* If they're using tdb_append(), it implies they're growing record. */
+ ret = replace_data(tdb, h, key, new_dbuf, bucket, off, old_room, true);
+ unlock_lists(tdb, start, num, F_WRLCK);
+ free(newdata);
+
+ if (unlikely(ret == 1)) {
+ /* Expand, then try again. */
+ if (tdb_expand(tdb, key.dsize, dbuf.dsize, true) == -1)
+ return -1;
+ return tdb_append(tdb, key, dbuf);
+ }
- /* By simple trial and error, this roughly approximates a 60%
- * full measure. */
- if (unlikely(end - start > 4 * tdb->header.v.hash_bits - 32))
+ /* FIXME: by simple simulation, this approximated 60% full.
+ * Check in real case! */
+ if (unlikely(num > 4 * tdb->header.v.hash_bits - 30))
enlarge_hash(tdb);
- return 0;
+ return ret;
fail:
- unlock_lists(tdb, start, end, 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, end, room;
+ tdb_off_t off, start, num, bucket;
+ struct tdb_used_record rec;
uint64_t h;
- struct tdb_used_record pad, *r;
struct tdb_data ret;
h = tdb_hash(tdb, key.dptr, key.dsize);
- off = find_bucket_and_lock(tdb, &key, h, &start, &end, &room, F_RDLCK);
- if (off == 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;
if (!off) {
- unlock_lists(tdb, start, end, F_RDLCK);
- tdb->ecode = TDB_SUCCESS;
- return tdb_null;
- }
-
- r = tdb_get(tdb, off, &pad, sizeof(*r));
- if (!r) {
- unlock_lists(tdb, start, end, F_RDLCK);
- return tdb_null;
+ tdb->ecode = TDB_ERR_NOEXIST;
+ 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(r);
- ret.dptr = tdb_alloc_read(tdb, off + sizeof(*r) + key.dsize,
- ret.dsize);
- unlock_lists(tdb, start, end, F_RDLCK);
+ unlock_lists(tdb, start, num, F_RDLCK);
return ret;
}
-static int hash_add(struct tdb_context *tdb, uint64_t h, tdb_off_t off)
-{
- tdb_off_t i, hoff, len, num;
-
- i = (h & ((1ULL << tdb->header.v.hash_bits) - 1));
- hoff = tdb->header.v.hash_off + i * sizeof(tdb_off_t);
- len = (1ULL << tdb->header.v.hash_bits) - i;
-
- /* Look for next space. */
- num = tdb_find_zero_off(tdb, hoff, len);
- if (unlikely(num == len)) {
- hoff = tdb->header.v.hash_off;
- len = (1ULL << tdb->header.v.hash_bits);
- num = tdb_find_zero_off(tdb, hoff, len);
- if (i == len)
- return -1;
- }
- /* FIXME: Encode extra hash bits! */
- return tdb_write_off(tdb, hoff + num * sizeof(tdb_off_t), off);
-}
-
-static int unlink_used_record(struct tdb_context *tdb, tdb_off_t chain,
- uint64_t *extra_locks)
+int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
{
- tdb_off_t num, len, i, hoff;
-
- /* FIXME: Maybe lock more in search? Maybe don't lock if scan
- * finds none? */
-again:
- len = (1ULL << tdb->header.v.hash_bits) - (chain + 1);
- hoff = tdb->header.v.hash_off + (chain + 1) * sizeof(tdb_off_t);
- num = tdb_find_zero_off(tdb, hoff, len);
-
- /* We want to lock the zero entry, too. In the wrap case,
- * this locks one extra. That's harmless. */
- num++;
-
- for (i = chain + 1; i < chain + 1 + num; i++) {
- if (tdb_lock_list(tdb, i, F_WRLCK, TDB_LOCK_WAIT) == -1) {
- if (i != chain + 1)
- unlock_lists(tdb, chain + 1, i-1, F_WRLCK);
- return -1;
- }
- }
+ tdb_off_t i, bucket, off, start, num;
+ struct tdb_used_record rec;
+ uint64_t h;
- /* The wrap case: we need those locks out of order! */
- if (unlikely(num == len + 1)) {
- *extra_locks = tdb_find_zero_off(tdb, tdb->header.v.hash_off,
- 1ULL << tdb->header.v.hash_bits);
- (*extra_locks)++;
- for (i = 0; i < *extra_locks; i++) {
- if (tdb_lock_list(tdb, i, F_WRLCK, TDB_LOCK_NOWAIT)) {
- /* Failed. Caller must lock in order. */
- if (i)
- unlock_lists(tdb, 0, i-1, F_WRLCK);
- unlock_lists(tdb, chain + 1, chain + num,
- F_WRLCK);
- return 1;
- }
- }
- num += *extra_locks;
- }
+ h = tdb_hash(tdb, key.dptr, key.dsize);
+ start = tdb_lock_list(tdb, h, F_WRLCK, TDB_LOCK_WAIT);
+ if (unlikely(start == TDB_OFF_ERR))
+ return -1;
- /* Now we have the locks, be certain that offset is still 0! */
- hoff = tdb->header.v.hash_off
- + (((chain + num) * sizeof(tdb_off_t))
- & ((1ULL << tdb->header.v.hash_bits) - 1));
+ /* FIXME: Fastpath: if next is zero, we can delete without lock,
+ * since this lock protects us. */
+ off = find_and_lock_slow(tdb, key, h, F_WRLCK,
+ &start, &num, &bucket, &rec);
+ if (unlikely(off == TDB_OFF_ERR))
+ return -1;
- if (unlikely(tdb_read_off(tdb, hoff) != 0)) {
- unlock_lists(tdb, chain + 1, chain + num, F_WRLCK);
- goto again;
+ if (!off) {
+ /* FIXME: We could optimize not found case if it mattered, by
+ * reading offset after first lock: if it's zero, goto here. */
+ unlock_lists(tdb, start, num, F_WRLCK);
+ tdb->ecode = TDB_ERR_NOEXIST;
+ return -1;
}
+ /* Since we found the entry, we must have locked it and a zero. */
+ assert(num >= 2);
- /* OK, all locked. Unlink first one. */
- hoff = tdb->header.v.hash_off + chain * sizeof(tdb_off_t);
- if (tdb_write_off(tdb, hoff, 0) == -1)
+ /* This actually unlinks it. */
+ if (tdb_write_off(tdb, hash_off(tdb, bucket), 0) == -1)
goto unlock_err;
- /* Rehash the rest. */
- for (i = 1; i < num; i++) {
- tdb_off_t off;
- uint64_t h;
+ /* Rehash anything following. */
+ for (i = bucket+1; i != bucket + num - 1; i++) {
+ tdb_off_t hoff, off2;
+ uint64_t h2;
- hoff = tdb->header.v.hash_off
- + (((chain + i) * sizeof(tdb_off_t))
- & ((1ULL << tdb->header.v.hash_bits) - 1));
- off = tdb_read_off(tdb, hoff);
- if (unlikely(off == TDB_OFF_ERR))
+ hoff = hash_off(tdb, i);
+ off2 = tdb_read_off(tdb, hoff);
+ 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? */
- h = hash_record(tdb, off);
+ h2 = hash_record(tdb, off2);
/* Is it happy where it is? */
- if ((h & ((1ULL << tdb->header.v.hash_bits)-1)) == (chain + i))
+ if (hash_off(tdb, h2) == hoff)
continue;
/* Remove it. */
goto unlock_err;
/* Rehash it. */
- if (hash_add(tdb, h, off) == -1)
+ if (hash_add(tdb, h2, off2) == -1)
goto unlock_err;
}
- unlock_lists(tdb, chain + 1, chain + num, F_WRLCK);
+
+ /* Free the deleted entry. */
+ if (add_free_record(tdb, off,
+ sizeof(struct tdb_used_record)
+ + rec_key_length(&rec)
+ + rec_data_length(&rec)
+ + rec_extra_padding(&rec)) != 0)
+ goto unlock_err;
+
+ unlock_lists(tdb, start, num, F_WRLCK);
return 0;
unlock_err:
- unlock_lists(tdb, chain + 1, chain + num, F_WRLCK);
+ unlock_lists(tdb, start, num, F_WRLCK);
return -1;
}
-int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
-{
- tdb_off_t off, start, end, room, extra_locks = 0;
- uint64_t h;
- int ret;
-
- h = tdb_hash(tdb, key.dptr, key.dsize);
- off = find_bucket_and_lock(tdb, &key, h, &start, &end, &room, F_WRLCK);
- if (off == TDB_OFF_ERR)
- return -1;
-
- if (off == 0) {
- unlock_lists(tdb, start, end, F_WRLCK);
- tdb->ecode = TDB_ERR_NOEXIST;
- return -1;
- }
-
- ret = unlink_used_record(tdb, end, &extra_locks);
- if (unlikely(ret == 1)) {
- unsigned int i;
-
- unlock_lists(tdb, start, end, F_WRLCK);
-
- /* We need extra locks at the start. */
- for (i = 0; i < extra_locks; i++) {
- if (tdb_lock_list(tdb, i, F_WRLCK, TDB_LOCK_WAIT)) {
- if (i)
- unlock_lists(tdb, 0, i-1, F_WRLCK);
- return -1;
- }
- }
- /* Try again now we're holding more locks. */
- ret = tdb_delete(tdb, key);
- unlock_lists(tdb, 0, i, F_WRLCK);
- return ret;
- }
- unlock_lists(tdb, start, end, F_WRLCK);
- return ret;
-}
-
int tdb_close(struct tdb_context *tdb)
{
struct tdb_context **i;
return ret;
}
+
+enum TDB_ERROR tdb_error(struct tdb_context *tdb)
+{
+ return tdb->ecode;
+}
projects / ccan / blobdiff