tree 3c9133ae5b349aeec8c0a93338b9dd13b9c9dac1
parent cdce214e39814fd46d47e0e660ca3ddf3fdce8a6
author Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> 1273409513 +0900
committer Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> 1273458754 +0900

nilfs2: disallow remount of snapshot from/to a regular mount

Snapshots and regular ro/rw mounts are essentially-different within
the meaning whether the checkpoint is static or not and is marked with
a snapshot flag or not.

The current implemenation, however, allows to remount a snapshot to a
regular rw-mount if the checkpoint number equals the latest one.

This transition is actually impossible since changing a checkpoint to
a snapshot makes another checkpoint, thus the condition is never
satisfied.

This fixes the weird state of affairs, and specifically separates
snapshots and regular rw/ro-mounts.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>