Hello, It seems that Bittorrent Sync always tries to open files on file system with read-write access, or at least checks if read-write access is possible. If there are files which Sync process doesn't have a permissions to write to, then these files are not transferred to other devices. I can understand that write permission is needed to update a file from other peers if it is changed on that peers, but what if all other shares used only read-only key, would it still be needed? Would it be possible to add such a feature to create a share with possibility to expose only a read-only key, thus allowing Sync to access files from file system in read-only mode? The use case for me is the following. I'm trying sync backups created by 'Bacula' software. On my computer Bacula creates backup files with 'bacula:tape' ownership and 0640 permissions (so group has only read permission). There is no built-in possibility to configure umask for bacula backups. For Sync I use separate user 'btsync' and group 'btsync'. If there were the feature I described above, I would add 'btsync' user to 'tape' group. I believe Sync could work with read-only access to files. I'm using 1.4.93 beta on Ubuntu Server 14.04.
