monitor: Fix directory symlink deletion handling

When a symlink to a direcotry is deleted inotify cannot tell it from a
regular file rendering all its children orphans.
This sometimes leads to an unexpected effect - they may appear later in
a newly created directory when it gets an id used by the deleted symlink.

monitor.c

@@ -366,21 +366,13 @@ monitor_insert_directory(int fd, char *name, const char * path)
 }
 
 int
-monitor_remove_directory(int fd, const char * path)
+monitor_remove_tree(const char * path)
 {
 	char * sql;
 	char **result;
 	int64_t detailID = 0;
 	int rows, i, ret = 1;
 
-	/* Invalidate the scanner cache so we don't insert files into non-existent containers */
-	valid_cache = 0;
-#ifdef HAVE_WATCH
-	if( fd > 0 )
-	{
-		monitor_remove_watch(fd, path);
-	}
-#endif
 	sql = sqlite3_mprintf("SELECT ID from DETAILS where (PATH > '%q/' and PATH <= '%q/%c')"
 	                      " or PATH = '%q'", path, path, 0xFF, path);
 	if( (sql_get_table(db, sql, &result, &rows, NULL) == SQLITE_OK) )
@@ -403,3 +395,17 @@ monitor_remove_directory(int fd, const char * path)
 
 	return ret;
 }
+
+int
+monitor_remove_directory(int fd, const char * path)
+{
+	/* Invalidate the scanner cache so we don't insert files into non-existent containers */
+	valid_cache = 0;
+#ifdef HAVE_WATCH
+	if( fd > 0 )
+	{
+		monitor_remove_watch(fd, path);
+	}
+#endif
+    return monitor_remove_tree(path);
+}

monitor.h

@@ -1,6 +1,7 @@
 int monitor_insert_file(const char *name, const char *path);
 int monitor_insert_directory(int fd, char *name, const char * path);
 int monitor_remove_file(const char * path);
+int monitor_remove_tree(const char * path);
 int monitor_remove_directory(int fd, const char * path);
 
 #if defined(HAVE_INOTIFY) || defined(HAVE_KQUEUE)

monitor_inotify.c

@@ -366,7 +366,16 @@ inotify_thread(void *arg)
 					if ( event->mask & IN_ISDIR )
 						monitor_remove_directory(pollfds[0].fd, path_buf);
 					else
+					{
 						monitor_remove_file(path_buf);
+						/*
+						 * When a symlink to a directory is deleted
+						 * we cannot tell it from a regular file deletion
+						 * to prevent its children from becoming orphans
+						 * we delete the whole tree when it exists
+						 */
+						monitor_remove_tree(path_buf);
+					}
 				}
 				free(esc_name);
 			}