tdb: cleanup: tdb_nest_lock/tdb_nest_unlock

Because fcntl locks don't nest, we track them in the tdb->lockrecs array
and only place/release them when the count goes to 1/0.  We only do this
for record locks, so we simply place the list number (or -1 for the free
list) in the structure.

To generalize this:

1) Put the offset rather than list number in struct tdb_lock_type.
2) Rename _tdb_lock() to tdb_nest_lock, make it non-static and move the
   allrecord check out to the callers (except the mark case which doesn't
   care).
3) Rename _tdb_unlock() to tdb_nest_unlock(), make it non-static and
   move the allrecord out to the callers (except mark again).

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

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h
index 2e5679690f..4e4816bd4a 100644
--- a/lib/tdb/common/tdb_private.h
+++ b/lib/tdb/common/tdb_private.h
@@ -151,7 +151,7 @@ struct tdb_header {
 };
 
 struct tdb_lock_type {
-	int list;
+	uint32_t off;
 	uint32_t count;
 	uint32_t ltype;
 };
@@ -224,6 +224,10 @@ int tdb_munmap(struct tdb_context *tdb);
 void tdb_mmap(struct tdb_context *tdb);
 int tdb_lock(struct tdb_context *tdb, int list, int ltype);
 int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype);
+int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
+		  enum tdb_lock_flags flags);
+int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
+		    bool mark_lock);
 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
 int tdb_brlock(struct tdb_context *tdb,
 	       int rw_type, tdb_off_t offset, size_t len,