Changeset 847 for branches/samba-3.5.x/lib/tdb/common/io.c

Timestamp:

Feb 14, 2014, 7:01:54 PM (11 years ago)

Author:

Silvan Scherrer

Message:

samba server 3.5: bring 3.5 code base in line with 3.6

File:

• branches/samba-3.5.x/lib/tdb/common/io.c (modified) (2 diffs)

branches/samba-3.5.x/lib/tdb/common/io.c

@@ -91 +91 @@
 
 #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, off, F_WRLCK, F_SETLK, 0, len);
+        // 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 = 0;
+        upgradeLockRC = tdb_brlock( tdb, off, F_WRLCK, F_SETLK, 0, len);
+        if (upgradeLockRC != 0) {
+                tdb_brlock(tdb, off, F_UNLCK, F_SETLK, 0, len);
+                upgradeLockRC = tdb_brlock(tdb, off, F_WRLCK, F_SETLK, 0, len);
+        }
         TDB_LOG((tdb, TDB_DEBUG_TRACE,"upgrading lock at %d len=%d "
                 "before writing %s (rc=%d).\n", off, len,
-                 upgradeLockRC ? "was successfull":"failed", upgradeLockRC));
+                 upgradeLockRC ? "failed":"was successfull", upgradeLockRC));
 #endif
 
@@ -137 +146 @@
 
 #ifdef __OS2__ // remove our lock, if upgrade succeded
-                        if (upgradeLockRC == 0)
-                                tdb_brlock( tdb, off, F_UNLCK, F_SETLK, 0, len);
+        if (upgradeLockRC == 0)
+                tdb_brlock( tdb, off, F_UNLCK, F_SETLK, 0, len);
 #endif