inotify: added setting "auto_update_depth"

Limits the depth of the watched directories.  This is useful to keep
resource usage down and speed up MPD startup.

doc/mpd.conf.5

@@ -253,6 +253,10 @@ comments.
 This specifies the wheter to support automatic update of music database when
 files are changed in music_directory. The default is to disable autoupdate
 of database.
+.TP
+.B auto_update_depth <N>
+Limit the depth of the directories being watched, 0 means only watch
+the music directory itself.  There is no limit by default.
 .SH REQUIRED AUDIO OUTPUT PARAMETERS
 .TP
 .B type <type>

doc/mpdconf.example

@@ -118,6 +118,12 @@
 # music_directory are changed.
 #
 #auto_update	"yes"
+#
+# Limit the depth of the directories being watched, 0 means only watch
+# the music directory itself.  There is no limit by default.
+#
+#auto_update_depth "3"
+#
 ###############################################################################
 
 

src/conf.c

@@ -94,6 +94,7 @@ static struct config_entry config_entries[] = {
 	{ .name = CONF_GAPLESS_MP3_PLAYBACK, false, false },
 	{ .name = CONF_PLAYLIST_PLUGIN, true, true },
 	{ .name = CONF_AUTO_UPDATE, false, false },
+	{ .name = CONF_AUTO_UPDATE_DEPTH, false, false },
 	{ .name = "filter", true, true },
 };
 

src/conf.h

@@ -70,6 +70,7 @@
 #define CONF_GAPLESS_MP3_PLAYBACK	"gapless_mp3_playback"
 #define CONF_PLAYLIST_PLUGIN "playlist_plugin"
 #define CONF_AUTO_UPDATE		"auto_update"
+#define CONF_AUTO_UPDATE_DEPTH "auto_update_depth"
 
 #define DEFAULT_PLAYLIST_MAX_LENGTH (1024*16)
 #define DEFAULT_PLAYLIST_SAVE_ABSOLUTE_PATHS false

src/inotify_update.c

@@ -56,6 +56,7 @@ struct watch_directory {
 
 static struct mpd_inotify_source *inotify_source;
 
+static unsigned inotify_max_depth;
 static struct watch_directory inotify_root;
 static GTree *inotify_directories;
 
@@ -140,15 +141,21 @@ static bool skip_path(const char *path)
 
 static void
 recursive_watch_subdirectories(struct watch_directory *directory,
-			       const char *path_fs)
+			       const char *path_fs, unsigned depth)
 {
 	GError *error = NULL;
 	DIR *dir;
 	struct dirent *ent;
 
 	assert(directory != NULL);
+	assert(depth <= inotify_max_depth);
 	assert(path_fs != NULL);
 
+	++depth;
+
+	if (depth > inotify_max_depth)
+		return;
+
 	dir = opendir(path_fs);
 	if (dir == NULL) {
 		g_warning("Failed to open directory %s: %s",
@@ -209,13 +216,26 @@ recursive_watch_subdirectories(struct watch_directory *directory,
 
 		tree_add_watch_directory(child);
 
-		recursive_watch_subdirectories(child, child_path_fs);
+		recursive_watch_subdirectories(child, child_path_fs, depth);
 		g_free(child_path_fs);
 	}
 
 	closedir(dir);
 }
 
+G_GNUC_PURE
+static unsigned
+watch_directory_depth(const struct watch_directory *d)
+{
+	assert(d != NULL);
+
+	unsigned depth = 0;
+	while ((d = d->parent) != NULL)
+		++depth;
+
+	return depth;
+}
+
 static void
 mpd_inotify_callback(int wd, unsigned mask,
 		     G_GNUC_UNUSED const char *name, G_GNUC_UNUSED void *ctx)
@@ -250,7 +270,8 @@ mpd_inotify_callback(int wd, unsigned mask,
 		} else
 			path_fs = root;
 
-		recursive_watch_subdirectories(directory, path_fs);
+		recursive_watch_subdirectories(directory, path_fs,
+					       watch_directory_depth(directory));
 		g_free(path_fs);
 	}
 
@@ -271,7 +292,7 @@ mpd_inotify_callback(int wd, unsigned mask,
 }
 
 void
-mpd_inotify_init(void)
+mpd_inotify_init(unsigned max_depth)
 {
 	struct directory *root;
 	char *path;
@@ -300,6 +321,8 @@ mpd_inotify_init(void)
 		return;
 	}
 
+	inotify_max_depth = max_depth;
+
 	inotify_root.name = path;
 	inotify_root.descriptor = mpd_inotify_source_add(inotify_source, path,
 							 IN_MASK, &error);
@@ -315,7 +338,7 @@ mpd_inotify_init(void)
 	inotify_directories = g_tree_new(compare);
 	tree_add_watch_directory(&inotify_root);
 
-	recursive_watch_subdirectories(&inotify_root, path);
+	recursive_watch_subdirectories(&inotify_root, path, 0);
 
 	mpd_inotify_queue_init();
 

src/inotify_update.h

@@ -25,7 +25,7 @@
 #ifdef HAVE_INOTIFY_INIT
 
 void
-mpd_inotify_init(void);
+mpd_inotify_init(unsigned max_depth);
 
 void
 mpd_inotify_finish(void);
@@ -33,7 +33,7 @@ mpd_inotify_finish(void);
 #else /* !HAVE_INOTIFY_INIT */
 
 static inline void
-mpd_inotify_init(void)
+mpd_inotify_init(G_GNUC_UNUSED unsigned max_depth)
 {
 }
 

src/main.c

@@ -379,7 +379,8 @@ int main(int argc, char *argv[])
 	success = config_get_bool(CONF_AUTO_UPDATE, false);
 #ifdef ENABLE_INOTIFY
 	if (success && mapper_has_music_directory())
-    		mpd_inotify_init();
+		mpd_inotify_init(config_get_unsigned(CONF_AUTO_UPDATE_DEPTH,
+						     G_MAXUINT));
 #else
 	if (success)
 		g_warning("inotify: auto_update was disabled. enable during compilation phase");