r15555: Make "change notify timeout" a per-share parameter - used

when there's no kernel or FAM change notify. If set to zero
this will turn off change notify for the share except when
we ourselves change something (renames / deletes etc. ).
Designed to help on large directory shares where a new
changenotify is issued between each delete. This will
be fixed correctly when we move to internal change notify
(eg. back-port Samba4 changenotify).
Jeremy.
(This used to be commit 5a17bffbcd5082fde79c241468a0ff2b5903d540)

3 files changed, 33 insertions, 4 deletions

diff --git a/source3/smbd/notify.c b/source3/smbd/notify.c
index b2d0fc3326..829ca3a736 100644
--- a/source3/smbd/notify.c
+++ b/source3/smbd/notify.c
@@ -135,7 +135,19 @@ void remove_pending_change_notify_requests_by_filename(files_struct *fsp, NTSTAT
 }
 
 /****************************************************************************
- Return true if there are pending change notifies.
+ Set the current change notify timeout to the lowest value across all service
+ values.
+****************************************************************************/
+
+void set_change_notify_timeout(int val)
+{
+	if (val > 0) {
+		cnotify->select_time = MIN(cnotify->select_time, val);
+	}
+}
+
+/****************************************************************************
+ Longest time to sleep for before doing a change notify scan.
 ****************************************************************************/
 
 int change_notify_timeout(void)
diff --git a/source3/smbd/notify_hash.c b/source3/smbd/notify_hash.c
index a98a028fae..0787a3eec5 100644
--- a/source3/smbd/notify_hash.c
+++ b/source3/smbd/notify_hash.c
@@ -81,6 +81,11 @@ static BOOL notify_hash(connection_struct *conn, char *path, uint32 flags,
                 return True;
         }
 
+	if (lp_change_notify_timeout(SNUM(conn)) <= 0) {
+		/* It change notify timeout has been disabled, never scan the directory. */
+		return True;
+	}
+
 	/*
 	 * If we are to watch for changes that are only stored
 	 * in inodes of files, not in the directory inode, we must
@@ -179,9 +184,17 @@ static BOOL hash_check_notify(connection_struct *conn, uint16 vuid, char *path,
 {
 	struct change_data *data = (struct change_data *)datap;
 	struct change_data data2;
+	int cnto = lp_change_notify_timeout(SNUM(conn));
+
+	if (t && cnto <= 0) {
+		/* Change notify turned off on this share.
+		 * Only scan when (t==0) - we think something changed. */
+		return False;
+	}
 
-	if (t && t < data->last_check_time + lp_change_notify_timeout())
+	if (t && t < data->last_check_time + cnto) {
 		return False;
+	}
 
 	if (!change_to_user(conn,vuid))
 		return True;
@@ -201,8 +214,9 @@ static BOOL hash_check_notify(connection_struct *conn, uint16 vuid, char *path,
 		return True;
 	}
 
-	if (t)
+	if (t) {
 		data->last_check_time = t;
+	}
 
 	change_to_root_user();
 
@@ -229,7 +243,7 @@ struct cnotify_fns *hash_notify_init(void)
 	cnotify.register_notify = hash_register_notify;
 	cnotify.check_notify = hash_check_notify;
 	cnotify.remove_notify = hash_remove_notify;
-	cnotify.select_time = lp_change_notify_timeout();
+	cnotify.select_time = 60; /* Start with 1 minute default. */
 	cnotify.notification_fd = -1;
 
 	return &cnotify;
diff --git a/source3/smbd/service.c b/source3/smbd/service.c
index ba87d0743d..7ca2380e0d 100644
--- a/source3/smbd/service.c
+++ b/source3/smbd/service.c
@@ -930,6 +930,9 @@ static connection_struct *make_connection_snum(int snum, user_struct *vuser,
 		dbgtext( "(pid %d)\n", (int)sys_getpid() );
 	}
 	
+	/* Setup the minimum value for a change notify wait time (seconds). */
+	set_change_notify_timeout(lp_change_notify_timeout(snum));
+
 	/* we've finished with the user stuff - go back to root */
 	change_to_root_user();
 	return(conn);