Hi, some days ago I posted this request. I had no reaction so far, so I decided to post it again here. Maybe not the best place, if so let me know. I'm working on a construction using where a FUSE fs plays an important role, and it's basically an overlay fs. See: http://linux.bononline.nl/wiki/index.php/Mount.md5key and for a screenshot: http://linux.bononline.nl/wiki/index.php/Introduction_and_motivation#Preview_of_what_my_construction_offers Now I would like to ask for an interface between the Inotfy subsystem in VFS and the mounted fs. For example: the fusexmp FUSE fs takes as backend the root /, so when mounting you see a mirror of the root at the mountpoint. No user a mounts it like: mkdir ~/mount fusexmp /home/a/mount When user a (or any other user ) has an app which has set a watch at the directory /home/a/mount/tmp, watching for changes here, it will see a change if user a does: cd ~/mount/tmp touch testfile Now when the same user a does: cd /tmp rm testfile this will not be notified by the watch set at /home/a/mount/tmp This logical: the VFS does not and cannot know the directories /home/a/mount/tmp and /tmp are related, and it should not. What my suggestion is to add some communication between the VFS and the driver (in this case FUSE) about inotify watches being set and removed, and additional tha ability for the driver to notify VFS when something has changed. So for the example of above it goes like: the FUSE fs gets a signal there is a watch set at /home/a/mount/tmp (=tmp under the mountpoint). The fuse fs sets a simular inotify watch on the backend, in this case /tmp, and will listen for changes on the inode. When it recieves some data(inotify events), it will push them forward to the inotify watch on /home/a/mount/tmp. This is upto the developer of the FUSE fs to implement this, but required to make this work is: a. when there is a notify watch set on a mounted FUSE fs, the VFS should send the FUSE fs a signal a watch (with a mask) is set on a particular inode. (and also when it's removed) b. the VFS should be able to listen to notify events coming from the FUSE fs. Actually the VFS is signalling to the FUSE fs that it wants to have an inode to be up to date, and to be informed when changes occur. This example is about FUSE, but it also counts for a fs like cifs. There the backend is a SMB share, and the SMB server has to support inotify to make this work. I hope you get the picture, Stef Bon Voorburg the Netherlands -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
