INTRO (9) NetBSD Kernel Developer's Manual INTRO (9) NAME ...

FSTRANS (9) NetBSD Kernel Developer’s Manual FSTRANS (9)NAMEfstrans, fstrans_setstate, fstrans_getstate, fstrans_start,fstrans_start_nowait, fstrans_done, fstrans_is_owner, fscow_establish,fscow_disestablish, fscow_run —file system suspension helper subsystemSYNOPSIS#include #include intfstrans_setstate(struct mount ∗mp , enum fstrans_state new_state);enum fstrans_statefstrans_getstate(struct mount ∗mp);voidfstrans_start(struct mount ∗mp , enum fstrans_lock_type lock_type);intfstrans_start_nowait(struct mount ∗mp , enum fstrans_lock_type lock_type);voidfstrans_done(struct mount ∗mp);intfstrans_is_owner(struct mount ∗mp);intfscow_establish(struct mount ∗mp , int (∗func)(void ∗, struct buf ∗, bool) ,void ∗cookie);intfscow_disestablish(struct mount ∗mp ,int (∗func)(void ∗, struct buf ∗, bool) , void ∗cookie);intfscow_run(struct buf ∗bp , bool data_valid);DESCRIPTIONThe fstrans subsystem is a set of operations to assist file system suspension. These operations must notbe used outside of file systems.File systems supporting this subsystem must set the flag IMNT_HAS_TRANS in mnt_iflag.File systems are always in one of these states:FSTRANS_NORMAL normal operations.FSTRANS_SUSPENDING preparing a suspension.FSTRANS_SUSPENDED suspended.This state is represented by enum fstrans_state.fstrans_getstate(mp)returns the current state of the file system mp.fstrans_setstate(mp , new_state)changes the state of the file system mp to new_state.All file system operations use a fstrans lock. This lock is recursive. A thread already owning a lock willalways get another lock. The lock has two variants:NetBSD 3.0 December 2, 2007 1