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)

4 files changed, 37 insertions, 8 deletions

diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index c4ef9ef3ea..695e7f1aac 100644
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -220,7 +220,6 @@ typedef struct {
 	int lm_interval;
 	int announce_as;	/* This is initialised in init_globals */
 	int machine_password_timeout;
-	int change_notify_timeout;
 	int map_to_guest;
 	int oplock_break_wait_time;
 	int winbind_cache_time;
@@ -449,6 +448,7 @@ typedef struct {
 	int iAioReadSize;
 	int iAioWriteSize;
 	int iMap_readonly;
+	int ichange_notify_timeout;
 	param_opt_struct *param_opt;
 
 	char dummy[3];		/* for alignment */
@@ -587,6 +587,7 @@ static service sDefault = {
 	0,			/* iAioReadSize */
 	0,			/* iAioWriteSize */
 	MAP_READONLY_YES,	/* iMap_readonly */
+	60,			/* ichange_notify_timeout = 1 minute default. */
 	
 	NULL,			/* Parametric options */
 
@@ -996,7 +997,7 @@ static struct parm_struct parm_table[] = {
 	{N_("Tuning Options"), P_SEP, P_SEPARATOR}, 
 
 	{"block size", P_INTEGER, P_LOCAL, &sDefault.iBlock_size, NULL, NULL, FLAG_ADVANCED | FLAG_SHARE | FLAG_GLOBAL}, 
-	{"change notify timeout", P_INTEGER, P_GLOBAL, &Globals.change_notify_timeout, NULL, NULL, FLAG_ADVANCED}, 
+	{"change notify timeout", P_INTEGER, P_LOCAL, &sDefault.ichange_notify_timeout, NULL, NULL, FLAG_ADVANCED}, 
 	{"deadtime", P_INTEGER, P_GLOBAL, &Globals.deadtime, NULL, NULL, FLAG_ADVANCED}, 
 	{"getwd cache", P_BOOL, P_GLOBAL, &use_getwd_cache, NULL, NULL, FLAG_ADVANCED}, 
 	{"keepalive", P_INTEGER, P_GLOBAL, &keepalive, NULL, NULL, FLAG_ADVANCED}, 
@@ -1507,7 +1508,6 @@ static void init_globals(BOOL first_time_only)
 	Globals.max_wins_ttl = 60 * 60 * 24 * 6;	/* 6 days default. */
 	Globals.min_wins_ttl = 60 * 60 * 6;	/* 6 hours default. */
 	Globals.machine_password_timeout = 60 * 60 * 24 * 7;	/* 7 days default. */
-	Globals.change_notify_timeout = 60;	/* 1 minute default. */
 	Globals.bKernelChangeNotify = True;	/* On if we have it. */
 	Globals.bFamChangeNotify = True;	/* On if we have it. */
 	Globals.lm_announce = 2;	/* = Auto: send only if LM clients found */
@@ -1934,7 +1934,6 @@ static FN_GLOBAL_INTEGER(lp_announce_as, &Globals.announce_as)
 FN_GLOBAL_INTEGER(lp_lm_announce, &Globals.lm_announce)
 FN_GLOBAL_INTEGER(lp_lm_interval, &Globals.lm_interval)
 FN_GLOBAL_INTEGER(lp_machine_password_timeout, &Globals.machine_password_timeout)
-FN_GLOBAL_INTEGER(lp_change_notify_timeout, &Globals.change_notify_timeout)
 FN_GLOBAL_INTEGER(lp_map_to_guest, &Globals.map_to_guest)
 FN_GLOBAL_INTEGER(lp_oplock_break_wait_time, &Globals.oplock_break_wait_time)
 FN_GLOBAL_INTEGER(lp_lock_spin_count, &Globals.iLockSpinCount)
@@ -2066,6 +2065,7 @@ FN_LOCAL_INTEGER(lp_allocation_roundup_size, iallocation_roundup_size)
 FN_LOCAL_INTEGER(lp_aio_read_size, iAioReadSize)
 FN_LOCAL_INTEGER(lp_aio_write_size, iAioWriteSize)
 FN_LOCAL_INTEGER(lp_map_readonly, iMap_readonly)
+FN_LOCAL_INTEGER(lp_change_notify_timeout, ichange_notify_timeout)
 FN_LOCAL_CHAR(lp_magicchar, magic_char)
 FN_GLOBAL_INTEGER(lp_winbind_cache_time, &Globals.winbind_cache_time)
 FN_GLOBAL_LIST(lp_winbind_nss_info, &Globals.szWinbindNssInfo)
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);