ntdb: take advantage of direct access across expand.

This means we no longer have to unmap if we want to compare a record.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/lib/ntdb/hash.c b/lib/ntdb/hash.c
index ad1196ecdea5284a6409889e57de684b1d05a2df..b223668dbb33e8879b175585f195b5be1c97cb38 100644 (file)
--- a/lib/ntdb/hash.c
+++ b/lib/ntdb/hash.c
@@ -68,8 +68,7 @@ static ntdb_bool_err match(struct ntdb_context *ntdb,
                           const NTDB_DATA *key,
                           ntdb_off_t val,
                           struct ntdb_used_record *rec,
-                          const char **rptr,
-                          const ntdb_off_t **mapped)
+                          const char **rptr)
 {
        ntdb_off_t off;
        enum NTDB_ERROR ecode;
@@ -83,12 +82,6 @@ static ntdb_bool_err match(struct ntdb_context *ntdb,
                return false;
        }
 
-       /* Unmap before we try to read actual record, which may cause expand */
-       if (mapped) {
-               ntdb_access_release(ntdb, *mapped);
-               *mapped = NULL;
-       }
-
        off = val & NTDB_OFF_MASK;
        ecode = ntdb_read_convert(ntdb, off, rec, sizeof(*rec));
        if (ecode != NTDB_SUCCESS) {
@@ -151,7 +144,7 @@ ntdb_off_t find_and_lock(struct ntdb_context *ntdb,
        /* Directly in hash table? */
        if (!likely(is_chain(val))) {
                if (val) {
-                       berr = match(ntdb, h->h, &key, val, rec, rptr, NULL);
+                       berr = match(ntdb, h->h, &key, val, rec, rptr);
                        if (berr < 0) {
                                ecode = NTDB_OFF_TO_ERR(berr);
                                goto fail;
@@ -184,41 +177,32 @@ ntdb_off_t find_and_lock(struct ntdb_context *ntdb,
 
        h->table_size = rec_data_length(&chdr) / sizeof(ntdb_off_t);
 
+       arr = ntdb_access_read(ntdb, hbucket_off(h->table, 0),
+                              rec_data_length(&chdr), true);
+       if (NTDB_PTR_IS_ERR(arr)) {
+               ecode = NTDB_PTR_ERR(arr);
+               goto fail;
+       }
+
        found_empty = false;
        for (i = 0; i < h->table_size; i++) {
-               /* Careful!  match has to unmap this if we access a
-                * record (may cause mmap of database to move. */
-               if (!arr) {
-                       arr = ntdb_access_read(ntdb, hbucket_off(h->table, 0),
-                                              rec_data_length(&chdr), true);
-                       if (NTDB_PTR_IS_ERR(arr)) {
-                               ecode = NTDB_PTR_ERR(arr);
-                               goto fail;
-                       }
-               }
-
-               val = arr[i];
-               if (val == 0) {
+               if (arr[i] == 0) {
                        if (!found_empty) {
                                h->bucket = i;
                                found_empty = true;
                        }
                } else {
-                       berr = match(ntdb, h->h, &key, val, rec, rptr, &arr);
+                       berr = match(ntdb, h->h, &key, arr[i], rec, rptr);
                        if (berr < 0) {
                                ecode = NTDB_OFF_TO_ERR(berr);
-                               if (arr) {
-                                       ntdb_access_release(ntdb, arr);
-                               }
+                               ntdb_access_release(ntdb, arr);
                                goto fail;
                        }
                        if (berr) {
                                /* We found it! */
                                h->bucket = i;
-                               off = val & NTDB_OFF_MASK;
-                               if (arr) {
-                                       ntdb_access_release(ntdb, arr);
-                               }
+                               off = arr[i] & NTDB_OFF_MASK;
+                               ntdb_access_release(ntdb, arr);
                                return off;
                        }
                }
@@ -229,9 +213,7 @@ ntdb_off_t find_and_lock(struct ntdb_context *ntdb,
                h->bucket = i;
        }
 
-       if (arr) {
-               ntdb_access_release(ntdb, arr);
-       }
+       ntdb_access_release(ntdb, arr);
        return 0;
 
 fail: