VFSSUBR(9)             NetBSD Kernel Developer's Manual             VFSSUBR(9)

NAME
     vfssubr, vfs_getnewfsid, vfs_getvfs, vfs_export, vfs_showexport,
     vfs_export_lookup, vfs_setpublicfs, vfs_mountedon, vfs_mountroot,
     vfs_unmountall, vfs_busy, vfs_unbusy, vfs_rootmountalloc, vfs_shutdown,
     vfs_attach, vfs_detach, vfs_reinit, vfs_getopsbyname, vfs_suspend,
     vfs_resume -- high-level interface to kernel file system interface

SYNOPSIS
     #include <sys/param.h>
     #include <sys/mount.h>
     #include <sys/vnode.h>

     void
     vfs_getnewfsid(struct mount *mp);

     struct mount *
     vfs_getvfs(fsid_t *fsid);

     int
     vfs_export_lookup(struct mount *mp, struct netexport *nep,
         struct export_args *argp);

     int
     vfs_setpublicfs(struct mount *mp, struct netexport *nep,
         struct export_args *argp);

     int
     vfs_mountedon(struct vnode *vp);

     int
     vfs_mountroot(void);

     void
     vfs_unmountall(struct lwp *l);

     int
     vfs_busy(struct mount *mp, int flags, struct simplelock *interlkp);

     void
     vfs_unbusy(struct mount *mp);

     int
     vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp);

     void
     vfs_shutdown(void);

     int
     vfs_attach(struct vfsops *vfs);

     int
     vfs_detach(struct vfsops *vfs);

     void
     vfs_reinit(void);

     struct vfsops *
     vfs_getopsbyname(const char *name);

     int
     vfs_suspend(struct mount *mp, int nowait);

     void
     vfs_resume(struct mount *mp);

DESCRIPTION
     The high-level functions described in this page are the interface to the
     kernel file system interface (VFS).

FUNCTIONS
     vfs_getnewfsid(mp)
              Get a new unique file system id type for the file system speci-
              fied by the mount structure mp.  The file system id type is
              stored in mp->mnt_stat.f_fsidx.

     vfs_getvfs(fsid)
              Lookup a mount point with the file system identifier fsid.

     vfs_export_lookup(mp, nep, argp)
              Check client permission on the exportable file system specified
              by the mount structure mp.  The argument nam is the address of
              the networked client.  This function is used by file system type
              specific functions to verify that the client can access the file
              system.

     vfs_setpublicfs(mp, nep, argp)
              Set the publicly exported file system specified by the mount
              structure mp.

     vfs_mountedon(vp)
              Check to see if a file system is mounted on a block device spec-
              ified by the vnode vp.

     vfs_mountroot(void)
              Mount the root file system.

     vfs_unmountall(l)
              Unmount all file systems.

     vfs_busy(mp, flags, interlkp)
              Mark the mount point specified by mp as busy.  This function is
              used to synchronize access and to delay unmounting.  The inter-
              lock specified by argument interlkp is not released on failure.

     vfs_unbusy(mp)
              Free the busy file system specified by the mount structure mp.

     vfs_rootmountalloc(fstypename, devname, mpp)
              Lookup a file system type specified by the name fstypename and
              if found allocate and initialise a mount structure for it.  The
              allocated mount structure is returned in the address specified
              by mpp.  The device the root file system was mounted from is
              specified by the argument devname and is recorded in the new
              mount structure.

     vfs_shutdown()
              Sync and unmount all file systems before shutting down.  Invoked
              by cpu_reboot(9).

     vfs_attach(vfs)
              Establish file system vfs and initialise it.

     vfs_detach(vfs)
              Remove file system vfs from the kernel.

     vfs_reinit(void)
              Reinitialises all file systems within the kernel through file
              system-specific vfs operation (see vfsops(9)).

     vfs_getopsbyname(name)
              Given a file system name specified by name, look up the vfs
              operations for that file system (see vfsops(9)), or return NULL
              if file system isn't present in the kernel.

     vfs_suspend(mp, nowait)
              Request a mounted file system to suspend all operations.  All
              new operations to the file system are stopped.  After all opera-
              tions in progress have completed, the file system is synced to
              disk and the function returns.  If a file system suspension is
              currently in progress and nowait is set EWOULDBLOCK is returned.
              If the operation is successful, zero is returned, otherwise an
              appropriate error code is returned.

     vfs_resume(mp)
              Request a mounted file system to resume operations.

CODE REFERENCES
     This section describes places within the NetBSD source tree where actual
     code implementing or using the vfs operations can be found.  All path-
     names are relative to /usr/src.

     The vfs interface functions are implemented within the files
     sys/kern/vfs_subr.c, sys/kern/vfs_subr2.c, and sys/kern/vfs_init.c.

SEE ALSO
     intro(9), namei(9), vfs(9), vfsops(9), vnode(9), vnodeops(9)

NetBSD 5.0_STABLE              January 21, 2007              NetBSD 5.0_STABLE
