Fix bug #5980 - Race condition when granting level2 oplocks can cause break notify...

[samba.git] / source3 / smbd / oplock.c

diff --git a/source3/smbd/oplock.c b/source3/smbd/oplock.c
index c98d11426d49a63dcd08442df1846328ef12e480..261d8fd6702def7e9dec90b875adaf2dc7832662 100644 (file)
--- a/source3/smbd/oplock.c
+++ b/source3/smbd/oplock.c
@@ -821,10 +821,33 @@ void release_level_2_oplocks_on_change(files_struct *fsp)
 
                share_mode_entry_to_message(msg, share_entry);
 
-               messaging_send_buf(smbd_messaging_context(), share_entry->pid,
-                                  MSG_SMB_ASYNC_LEVEL2_BREAK,
-                                  (uint8 *)msg,
-                                  MSG_SMB_SHARE_MODE_ENTRY_SIZE);
+               /*
+                * Deal with a race condition when breaking level2
+                * oplocks. Don't send all the messages and release
+                * the lock, this allows someone else to come in and
+                * get a level2 lock before any of the messages are
+                * processed, and thus miss getting a break message.
+                * Ensure at least one entry (the one we're breaking)
+                * is processed immediately under the lock and becomes
+                * set as NO_OPLOCK to stop any waiter getting a level2.
+                * Bugid #5980.
+                */
+
+               if (procid_is_me(&share_entry->pid)) {
+                       DATA_BLOB blob = data_blob_const(msg,
+                                       MSG_SMB_SHARE_MODE_ENTRY_SIZE);
+                       process_oplock_async_level2_break_message(smbd_messaging_context(),
+                                               NULL,
+                                               MSG_SMB_ASYNC_LEVEL2_BREAK,
+                                               share_entry->pid,
+                                               &blob);
+               } else {
+                       messaging_send_buf(smbd_messaging_context(),
+                                       share_entry->pid,
+                                       MSG_SMB_ASYNC_LEVEL2_BREAK,
+                                       (uint8 *)msg,
+                                       MSG_SMB_SHARE_MODE_ENTRY_SIZE);
+               }
        }
 
        /* We let the message receivers handle removing the oplock state