tdb: fix tdb_check() on read-only TDBs to actually work.

[ccan] / ccan / tdb / check.c

diff --git a/ccan/tdb/check.c b/ccan/tdb/check.c
index c5469e9998122dc57eefcdb90ddb747cb99d684d..a9a9ece0da37c01eb87c0dbf3e4ac6ee05250d07 100644 (file)
--- a/ccan/tdb/check.c
+++ b/ccan/tdb/check.c
@@ -327,9 +327,17 @@ int tdb_check(struct tdb_context *tdb,
        struct tdb_record rec;
        bool found_recovery = false;
        tdb_len_t dead;
-
-       if (tdb_lockall_read(tdb) == -1)
-               return -1;
+       bool locked;
+
+       /* Read-only databases use no locking at all: it's best-effort.
+        * We may have a write lock already, so skip that case too. */
+       if (tdb->read_only || tdb->allrecord_lock.count != 0) {
+               locked = false;
+       } else {
+               if (tdb_lockall_read(tdb) == -1)
+                       return -1;
+               locked = true;
+       }
 
        /* Make sure we know true size of the underlying file. */
        tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
@@ -444,12 +452,16 @@ int tdb_check(struct tdb_context *tdb,
        }
 
        free(hashes);
-       tdb_unlockall_read(tdb);
+       if (locked) {
+               tdb_unlockall_read(tdb);
+       }
        return 0;
 
 free:
        free(hashes);
 unlock:
-       tdb_unlockall_read(tdb);
+       if (locked) {
+               tdb_unlockall_read(tdb);
+       }
        return -1;
 }