Hello, On 08/16/2012 05:59 PM, Zdenek Bouska wrote: > I found a problem with VFS's namespace_rwlock
Perhaps just a limitation of the current implementation with respect to future possible uses? > (uspace/srv/vfs/vfs_ops.c). It prevents from creating overlayer > filesystems like FUSE's fusexmp.c example [1][2]. Maybe even saving > filesystem data in other filesystem is not possible. > > VFS mount => overlayer FS mount => VFS stat on different FS file => > deadlock Can you be more specific? What are these 'overlayer' fs trying to do? > There is comment near the rwlock: > "This rwlock prevents the race between a triplet-to-VFS-node resolution > and a concurrent VFS operation which modifies the file system namespace." > > Is there another way how to prevent this race? Something like different > lock for each mounted FS. The namespace_rwlock is a simple solution for making sure the file namespace does not change under our hands, but it has its own problems. Surely one can change the implementation to use a more fine-grained locking scheme and adapt the rest of VFS to it. Jakub _______________________________________________ HelenOS-devel mailing list [email protected] http://lists.modry.cz/cgi-bin/listinfo/helenos-devel
