53cf50e081
Filesystems like ZFS must use what the kernel calls an anonymous super block. Basically, this is just a filesystem which is not backed by a single block device. Normally this block device's dev_t is stored in the super block. For anonymous super blocks a unique reserved dev_t is assigned as part of get_sb(). This sb->s_dev must then be set in the returned stat structures as stat->st_dev. This allows userspace utilities to easily detect the boundries of a specific filesystem. Tools such as 'du' depend on this for proper accounting. Additionally, under OpenSolaris the statfs->f_fsid is set to the device id. To preserve consistency with OpenSolaris we also set the fsid to the device id. Other Linux filesystem (ext) set the fsid to a unique value determined by the filesystems uuid. This value is unique but maintains no relationship to the device id. This may be desirable when exporting NFS filesystem because it minimizes to chance of a client observing the same fsid from two different servers. Closes #140
Native ZFS for Linux! ZFS is an advanced file system and volume manager which was originally developed for Solaris. It has been successfully ported to FreeBSD and now there is a functional Linux ZFS kernel port too. The port currently includes a fully functional and stable SPA, DMU, and ZVOL with a ZFS Posix Layer (ZPL) on the way!
$ ./configure
$ make pkg
Full documentation for building, configuring, and using ZFS can be found at: http://zfsonlinux.org