Ryan Moeller 7b4e27232d Add 'zfs rename -u' to rename without remounting ... Allow to rename file systems without remounting if it is possible. It is possible for file systems with 'mountpoint' property set to 'legacy' or 'none' - we don't have to change mount directory for them. Currently such file systems are unmounted on rename and not even mounted back. This introduces layering violation, as we need to update 'f_mntfromname' field in statfs structure related to mountpoint (for the dataset we are renaming and all its children). In my opinion it is worth it, as it allow to update FreeBSD in even cleaner way - in ZFS-only configuration root file system is ZFS file system with 'mountpoint' property set to 'legacy'. If root dataset is named system/rootfs, we can snapshot it (system/rootfs@upgrade), clone it (system/oldrootfs), update FreeBSD and if it doesn't boot we can boot back from system/oldrootfs and rename it back to system/rootfs while it is mounted as /. Before it was not possible, because unmounting / was not possible. Authored by: Pawel Jakub Dawidek <pjd@FreeBSD.org> Reviewed-by: Allan Jude <allan@klarasystems.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Ported by: Matt Macy <mmacy@freebsd.org> Signed-off-by: Ryan Moeller <ryan@iXsystems.com> Closes #10839		2020-09-01 16:14:16 -07:00
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sys	Add 'zfs rename -u' to rename without remounting	2020-09-01 16:14:16 -07:00
Makefile.am	OpenZFS restructuring - move platform specific headers	2019-09-05 09:34:54 -07:00