]> git.ozlabs.org Git - ccan/blobdiff - ccan/tdb2/free.c
tdb2: change API to return the error value.
[ccan] / ccan / tdb2 / free.c
index 49880f18dd51517601eca798d163e5e98b10b514..d2285567eb0efdf56dfd8d96ec0650845ef403e0 100644 (file)
@@ -1,7 +1,7 @@
- /* 
+ /*
    Trivial Database 2: free list/block handling
    Copyright (C) Rusty Russell 2010
-   
+
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
@@ -49,65 +49,67 @@ unsigned int size_to_bucket(tdb_len_t data_len)
        return bucket;
 }
 
-tdb_off_t first_flist(struct tdb_context *tdb)
+tdb_off_t first_ftable(struct tdb_context *tdb)
 {
-       return tdb_read_off(tdb, offsetof(struct tdb_header, free_list));
+       return tdb_read_off(tdb, offsetof(struct tdb_header, free_table));
 }
 
-tdb_off_t next_flist(struct tdb_context *tdb, tdb_off_t flist)
+tdb_off_t next_ftable(struct tdb_context *tdb, tdb_off_t ftable)
 {
-       return tdb_read_off(tdb, flist + offsetof(struct tdb_freelist, next));
+       return tdb_read_off(tdb, ftable + offsetof(struct tdb_freetable,next));
 }
 
-int tdb_flist_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;
        tdb_off_t off;
 
-       tdb->flist_off = off = first_flist(tdb);
-       tdb->flist = 0;
+       tdb->ftable_off = off = first_ftable(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) {
-                       tdb->flist_off = off;
-                       tdb->flist = count;
+                       tdb->ftable_off = off;
+                       tdb->ftable = count;
                        max = rnd;
                }
 
-               off = next_flist(tdb, off);
+               off = next_ftable(tdb, off);
                count++;
        }
-       return 0;
+       return TDB_SUCCESS;
 }
 
 /* Offset of a given bucket. */
-tdb_off_t bucket_off(tdb_off_t flist_off, unsigned bucket)
+tdb_off_t bucket_off(tdb_off_t ftable_off, unsigned bucket)
 {
-       return flist_off + offsetof(struct tdb_freelist, buckets)
+       return ftable_off + offsetof(struct tdb_freetable, buckets)
                + 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 flist_off,
+                               tdb_off_t ftable_off,
                                tdb_off_t bucket)
 {
        /* Speculatively search for a non-zero bucket. */
-       return tdb_find_nonzero_off(tdb, bucket_off(flist_off, 0),
+       return tdb_find_nonzero_off(tdb, bucket_off(ftable_off, 0),
                                    bucket, TDB_FREE_BUCKETS);
 }
 
 /* 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) {
@@ -116,106 +118,116 @@ static int remove_from_list(struct tdb_context *tdb,
                off = frec_prev(r) + offsetof(struct tdb_free_record, next);
        }
 
-#ifdef DEBUG
+#ifdef CCAN_TDB2_DEBUG
        if (tdb_read_off(tdb, off) != r_off) {
-               tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_DEBUG_FATAL,
-                        "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) {
                off = r->next + offsetof(struct tdb_free_record,magic_and_prev);
                /* r->next->prev = r->prev */
 
-#ifdef DEBUG
+#ifdef CCAN_TDB2_DEBUG
                if (tdb_read_off(tdb, off) & TDB_OFF_MASK != r_off) {
-                       tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_DEBUG_FATAL,
-                                  "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 flist_and_len; rest is set in enqueue_in_free */
-       new.flist_and_len = ((uint64_t)tdb->flist << (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);
-       if (new.next == TDB_OFF_ERR)
-               return -1;
+       if (TDB_OFF_IS_ERR(new.next)) {
+               return new.next;
+       }
 
        if (new.next) {
-#ifdef DEBUG
+#ifdef CCAN_TDB2_DEBUG
                if (tdb_read_off(tdb,
                                 new.next + offsetof(struct tdb_free_record,
                                                     magic_and_prev))
                    != magic) {
-                       tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_DEBUG_FATAL,
-                                  "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));
 
        len = len_with_header - sizeof(struct tdb_used_record);
 
-       b_off = bucket_off(tdb->flist_off, size_to_bucket(len));
-       if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) != 0)
-               return -1;
+       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) {
+               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)
@@ -245,26 +257,32 @@ static size_t record_leftover(size_t keylen, size_t datalen,
        return leftover;
 }
 
-static tdb_off_t flist_offset(struct tdb_context *tdb, unsigned int flist)
+static tdb_off_t ftable_offset(struct tdb_context *tdb, unsigned int ftable)
 {
        tdb_off_t off;
        unsigned int i;
 
-       if (likely(tdb->flist == flist))
-               return tdb->flist_off;
+       if (likely(tdb->ftable == ftable))
+               return tdb->ftable_off;
 
-       off = first_flist(tdb);
-       for (i = 0; i < flist; i++)
-               off = next_flist(tdb, off);
+       off = first_ftable(tdb);
+       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;
@@ -272,30 +290,41 @@ static int coalesce(struct tdb_context *tdb,
        while (end < tdb->map_size) {
                const struct tdb_free_record *r;
                tdb_off_t nb_off;
-               unsigned flist, bucket;
+               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) {
+               if (frec_magic(r) != TDB_FREE_MAGIC
+                   || frec_ftable(r) == TDB_FTABLE_NONE) {
                        tdb_access_release(tdb, r);
                        break;
                }
 
-               flist = frec_flist(r);
+               ftable = frec_ftable(r);
                bucket = size_to_bucket(frec_len(r));
-               nb_off = bucket_off(flist_offset(tdb, flist), 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. */
-               if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT) == -1) {
+               if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT)
+                   != TDB_SUCCESS) {
                        add_stat(tdb, alloc_coalesce_lockfail, 1);
                        break;
                }
 
                /* 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;
                }
@@ -306,14 +335,15 @@ static int coalesce(struct tdb_context *tdb,
                        break;
                }
 
-               if (unlikely(frec_flist(&rec) != flist)
+               if (unlikely(frec_ftable(&rec) != ftable)
                    || unlikely(size_to_bucket(frec_len(&rec)) != bucket)) {
                        add_stat(tdb, alloc_coalesce_race, 1);
                        tdb_unlock_free_bucket(tdb, nb_off);
                        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;
                }
@@ -325,68 +355,79 @@ 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_DEBUG_FATAL,
-                          "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.magic_and_prev = TDB_COALESCING_MAGIC
-               << (64 - TDB_OFF_UPPER_STEAL);
-       /* FIXME: Use 255 as invalid free list? */
-       rec.flist_and_len = end - off - sizeof(struct tdb_used_record);
-       if (tdb_write_convert(tdb, off, &rec, sizeof(rec)) != 0)
+       rec.ftable_and_len = (TDB_FTABLE_NONE << (64 - TDB_OFF_UPPER_STEAL))
+               | (end - off - sizeof(struct tdb_used_record));
+       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. */
 static tdb_off_t lock_and_alloc(struct tdb_context *tdb,
-                               tdb_off_t flist_off,
+                               tdb_off_t ftable_off,
                                tdb_off_t bucket,
                                size_t keylen, size_t datalen,
                                bool want_extra,
+                               unsigned magic,
                                unsigned hashlow)
 {
        tdb_off_t off, b_off,best_off;
        struct tdb_free_record best = { 0 };
        double multiplier;
        size_t size = adjust_size(keylen, datalen);
+       enum TDB_ERROR ecode;
 
        add_stat(tdb, allocs, 1);
 again:
-       b_off = bucket_off(flist_off, bucket);
+       b_off = bucket_off(ftable_off, bucket);
 
        /* FIXME: Try non-blocking wait first, to measure contention. */
        /* Lock this bucket. */
-       if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) == -1) {
-               return TDB_OFF_ERR;
+       ecode = tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT);
+       if (ecode != TDB_SUCCESS) {
+               return ecode;
        }
 
-       best.flist_and_len = -1ULL;
+       best.ftable_and_len = -1ULL;
        best_off = 0;
 
        /* Get slack if we're after extra. */
@@ -398,23 +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_DEBUG_FATAL,
-                                "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;
                }
 
@@ -435,14 +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;
        }
 
@@ -452,8 +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));
@@ -461,23 +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_used_header(tdb, &rec, 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);
 
@@ -489,16 +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 hashlow)
+                         unsigned magic, unsigned hashlow)
 {
-       tdb_off_t off, flist_off;
-       unsigned start_b, b, flist;
+       tdb_off_t off, ftable_off;
+       tdb_off_t start_b, b, ftable;
        bool wrapped = false;
 
        /* If they are growing, add 50% to get to higher bucket. */
@@ -508,50 +564,60 @@ static tdb_off_t get_free(struct tdb_context *tdb,
        else
                start_b = size_to_bucket(adjust_size(keylen, datalen));
 
-       flist_off = tdb->flist_off;
-       flist = tdb->flist;
-       while (!wrapped || flist_off != tdb->flist_off) {
+       ftable_off = tdb->ftable_off;
+       ftable = tdb->ftable;
+       while (!wrapped || ftable_off != tdb->ftable_off) {
                /* Start at exact size bucket, and search up... */
-               for (b = find_free_head(tdb, flist_off, start_b);
+               for (b = find_free_head(tdb, ftable_off, start_b);
                     b < TDB_FREE_BUCKETS;
-                    b = find_free_head(tdb, flist_off, b + 1)) {
+                    b = find_free_head(tdb, ftable_off, b + 1)) {
                        /* Try getting one from list. */
-                       off = lock_and_alloc(tdb, flist_off,
+                       off = lock_and_alloc(tdb, ftable_off,
                                             b, keylen, datalen, want_extra,
-                                            hashlow);
-                       if (off == TDB_OFF_ERR)
-                               return TDB_OFF_ERR;
+                                            magic, hashlow);
+                       if (TDB_OFF_IS_ERR(off))
+                               return off;
                        if (off != 0) {
                                if (b == start_b)
                                        add_stat(tdb, alloc_bucket_exact, 1);
                                if (b == TDB_FREE_BUCKETS - 1)
                                        add_stat(tdb, alloc_bucket_max, 1);
                                /* Worked?  Stay using this list. */
-                               tdb->flist_off = flist_off;
-                               tdb->flist = flist;
+                               tdb->ftable_off = ftable_off;
+                               tdb->ftable = ftable;
                                return off;
                        }
                        /* Didn't work.  Try next bucket. */
                }
 
-               /* Hmm, try next list. */
-               flist_off = next_flist(tdb, flist_off);
-               flist++;
+               if (TDB_OFF_IS_ERR(b)) {
+                       return b;
+               }
 
-               if (flist_off == 0) {
+               /* 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;
-                       flist_off = first_flist(tdb);
-                       flist = 0;
+                       ftable_off = first_ftable(tdb);
+                       if (TDB_OFF_IS_ERR(ftable_off)) {
+                               return ftable_off;
+                       }
+                       ftable = 0;
                }
        }
 
        return 0;
 }
 
-int set_used_header(struct tdb_context *tdb,
-                   struct tdb_used_record *rec,
-                   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;
 
@@ -559,27 +625,27 @@ int set_used_header(struct tdb_context *tdb,
        rec->magic_and_meta = (hashlow & ((1 << 11)-1))
                | ((actuallen - (keylen + datalen)) << 11)
                | (keybits << 43)
-               | (TDB_MAGIC << 48);
+               | ((uint64_t)magic << 48);
        rec->key_and_data_len = (keylen | (datalen << (keybits*2)));
 
        /* Encoding can fail on big values. */
        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_DEBUG_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;
+       enum TDB_ERROR ecode;
 
        /* We need room for the record header too. */
        wanted = sizeof(struct tdb_used_record) + size;
@@ -587,9 +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_DEBUG_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
@@ -601,20 +666,23 @@ static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
        wanted = adjust_size(0, wanted);
 
        /* Only one person can expand file at a time. */
-       if (tdb_lock_expand(tdb, F_WRLCK) != 0)
-               return -1;
+       ecode = tdb_lock_expand(tdb, F_WRLCK);
+       if (ecode != TDB_SUCCESS) {
+               return ecode;
+       }
 
        /* Someone else may have expanded the file, so retry. */
        old_size = tdb->map_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. */
@@ -626,7 +694,7 @@ static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
 
 /* This won't fail: it will expand the database if it has to. */
 tdb_off_t alloc(struct tdb_context *tdb, size_t keylen, size_t datalen,
-               uint64_t hash, bool growing)
+               uint64_t hash, unsigned magic, bool growing)
 {
        tdb_off_t off;
 
@@ -634,12 +702,15 @@ tdb_off_t alloc(struct tdb_context *tdb, size_t keylen, size_t datalen,
        assert(!tdb->direct_access);
 
        for (;;) {
-               off = get_free(tdb, keylen, datalen, growing, hash);
+               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;