Changeset 840

Timestamp:

Feb 4, 2014, 4:58:40 PM (12 years ago)

Author:

Silvan Scherrer

Message:

Samba Server 3.6: adjust locking code

Location:

trunk/server/lib/tdb/common

Files:

• io.c (modified) (1 diff)
• lock.c (modified) (3 diffs)

trunk/server/lib/tdb/common/io.c

@@ -92 +92 @@
 
 #ifdef __OS2__
-        // YD we must upgrade read locks to write locks (exclusive), otherwise
+        // YD we must upgrade read locks to write locks (exclusive), as otherwise
         // the owner (us) is not allowed to write to the file (different from unix)
         // if a wider previous lock is in effect, we cannot write lock our segment
         // (e.g. a lock_upgrade locks all the file), so we hope the previous lock 
         // is a write lock: do not wait for lock.
-        int upgradeLockRC = tdb_brlock( tdb, F_WRLCK, off, len, F_SETLK);
+        // so this is what we try here:
+        // 1. add a write lock and see if it works
+        // 2. if the write lock wasn't set, we try to unlock the segment
+        //    first and add the write lock afterwards 
+        int upgradeLockRC = tdb_brlock(tdb, F_WRLCK, off, len, TDB_LOCK_NOWAIT);
+        if (upgradeLockRC != 0) {
+                tdb_brunlock(tdb, F_RDLCK, off, len);
+                int upgradeLockRC = tdb_brlock(tdb, F_WRLCK, off, len, TDB_LOCK_NOWAIT);
+        }
         TDB_LOG((tdb, TDB_DEBUG_TRACE,"upgrading lock at %d len=%d "
                 "before writing %s (rc=%d).\n", off, len,

trunk/server/lib/tdb/common/lock.c

@@ -34 +34 @@
 
 static int fcntl_lock(struct tdb_context *tdb,
-                      int rw, off_t off, off_t len, bool waitflag)
+                      int rw, tdb_off_t off, size_t len, bool waitflag)
 {
         struct flock fl;
@@ -48 +48 @@
         fl.l_pid = 0;
 
+#ifdef __OS2__
+        int cmd = 0;
+        if (waitflag)
+                cmd = F_SETLKW;
+        else
+                cmd = F_SETLK;
+
+        int rc = fcntl(tdb->fd, cmd, &fl);
+        // if the first lock doesn't work and it's a complete lock,
+        // we split it in 2 parts. first hash size*4 and then the rest
+        if (rc != 0 && off == FREELIST_TOP && len == 0) { 
+                fl.l_len = tdb->header.hash_size * 4;
+                rc = fcntl(tdb->fd, cmd, &fl);
+                if (rc == 0) {
+                        fl.l_start = off + tdb->header.hash_size * 4;
+                        fl.l_len = LONG_MAX;
+                        rc = fcntl(tdb->fd, cmd, &fl);
+                }
+        }
+        return rc;
+#else
         if (waitflag)
                 return fcntl(tdb->fd, F_SETLKW, &fl);
         else
                 return fcntl(tdb->fd, F_SETLK, &fl);
-}
-
-static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
+#endif
+}
+
+static int fcntl_unlock(struct tdb_context *tdb, int rw, tdb_off_t off, size_t len)
 {
         struct flock fl;
@@ -248 +270 @@
         while (count--) {
                 struct timeval tv;
+#ifdef __OS2__
+                // we need to remove locks, as upgrade doesn't work
+                tdb_brunlock(tdb, F_RDLCK, FREELIST_TOP, 0);
+#endif
                 if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0,
                                TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {