1.\" $NetBSD: vfssubr.9,v 1.10 2004/04/21 01:05:35 christos Exp $ 2.\" 3.\" Copyright (c) 2003 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Gregory McGarry. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd January 10, 2004 38.Dt VFSSUBR 9 39.Os 40.Sh NAME 41.Nm vfssubr , 42.Nm vfs_getnewfsid , 43.Nm vfs_getvfs , 44.Nm vfs_export , 45.Nm vfs_showexport , 46.Nm vfs_export_lookup , 47.Nm vfs_setpublicfs , 48.Nm vfs_mountedon , 49.Nm vfs_mountroot , 50.Nm vfs_unmountall , 51.Nm vfs_busy , 52.Nm vfs_unbusy , 53.Nm vfs_rootmountalloc , 54.Nm vfs_shutdown , 55.Nm vfs_attach , 56.Nm vfs_detach , 57.Nm vfs_reinit , 58.Nm vfs_getopsbyname , 59.Nm vfs_write_suspend , 60.Nm vfs_write_resume 61.Nd high-level interface to kernel file system interface 62.Sh SYNOPSIS 63.In sys/param.h 64.In sys/mount.h 65.In sys/vnode.h 66.Ft void 67.Fn vfs_getnewfsid "struct mount *mp" 68.Ft struct mount * 69.Fn vfs_getvfs "fsid_t *fsid" 70.Ft int 71.Fn vfs_export "struct mount *mp" "struct netexport *nep" \ 72"struct export_args *argp" 73.Ft void 74.Fn vfs_showexport "struct mount *mp" "struct export_args *argp" \ 75"struct netexport *nep" 76.Ft int 77.Fn vfs_export_lookup "struct mount *mp" "struct netexport *nep" \ 78"struct export_args *argp" 79.Ft int 80.Fn vfs_setpublicfs "struct mount *mp" "struct netexport *nep" \ 81"struct export_args *argp" 82.Ft int 83.Fn vfs_mountedon "struct vnode *vp" 84.Ft int 85.Fn vfs_mountroot "void" 86.Ft void 87.Fn vfs_unmountall "struct proc *p" 88.Ft int 89.Fn vfs_busy "struct mount *mp" "int flags" "struct simplelock *interlkp" 90.Ft void 91.Fn vfs_unbusy "struct mount *mp" 92.Ft int 93.Fn vfs_rootmountalloc "char *fstypename" "char *devname" \ 94"struct mount **mpp" 95.Ft void 96.Fn vfs_shutdown "void" 97.Ft int 98.Fn vfs_attach "struct vfsops *vfs" 99.Ft int 100.Fn vfs_detach "struct vfsops *vfs" 101.Ft void 102.Fn vfs_reinit "void" 103.Ft struct vfsops * 104.Fn vfs_getopsbyname "const char *name" 105.Ft int 106.Fn vfs_write_suspend "struct mount *mp" "int slpflag" "int slptimeo" 107.Ft void 108.Fn vfs_write_resume "struct mount *mp" 109.Sh DESCRIPTION 110The high-level functions described in this page are the interface to 111the kernel file system interface (VFS). 112.Sh FUNCTIONS 113.Bl -tag -width compact 114.It Fn vfs_getnewfsid "mp" 115Get a new unique file system id type for the file system specified by 116the mount structure 117.Fa mp . 118The file system id type is stored in 119.Em mp-\*[Gt]mnt_stat.f_fsidx . 120.It Fn vfs_getvfs "fsid" 121Lookup a mount point with the file system identifier 122.Fa fsid . 123.It Fn vfs_export "mp" "nep" "argp" 124Undocumented. 125.It Fn vfs_showexport "mp" "argp" "nep" 126Undocumented. 127.It Fn vfs_export_lookup "mp" "nep" "argp" 128Check client permission on the exportable file system specified by the 129mount structure 130.Fa mp . 131The argument 132.Fa nam 133is the address of the networked client. 134This function is used by file system type specific functions to verify 135that the client can access the file system. 136.It Fn vfs_setpublicfs "mp" "nep" "argp" 137Set the publicly exported file system specified by the mount structure 138.Fa mp . 139.It Fn vfs_mountedon "vp" 140Check to see if a file system is mounted on a block device specified 141by the vnode 142.Fa vp . 143.It Fn vfs_mountroot "void" 144Mount the root file system. 145.It Fn vfs_unmountall "p" 146Unmount all file systems. 147.It Fn vfs_busy "mp" "flags" "interlkp" 148Mark the mount point specified by 149.Fa mp 150as busy. 151This function is used to synchronize access and to delay unmounting. 152The interlock specified by argument 153.Fa interlkp 154is not released on failure. 155.It Fn vfs_unbusy "mp" 156Free the busy file system specified by the mount structure 157.Fa mp . 158.It Fn vfs_rootmountalloc "fstypename" "devname" "mpp" 159Lookup a file system type specified by the name 160.Fa fstypename 161and if found allocate and initialise a mount structure for it. 162The allocated mount structure is returned in the address specified by 163.Fa mpp . 164The device the root file system was mounted from is specified by the 165argument 166.Fa devname 167and is recorded in the new mount structure. 168.It Fn vfs_shutdown 169Sync and unmount all file systems before shutting down. 170Invoked by 171.Xr cpu_reboot 9 . 172.It Fn vfs_attach "vfs" 173Establish file system 174.Fa vfs 175and initialise it. 176.It Fn vfs_detach "vfs" 177Remove file system 178.Fa vfs 179from the kernel. 180.It Fn vfs_reinit "void" 181Reinitialises all file systems within the kernel through file 182system-specific vfs operation (see 183.Xr vfsops 9 ) . 184.It Fn vfs_getopsbyname "name" 185Given a file system name specified by 186.Fa name , 187look up the vfs operations for that file system (see 188.Xr vfsops 9 ) , 189or return 190.Dv NULL 191if file system isn't present in the kernel. 192.It Fn vfs_write_suspend "mp" "slpflag" "slptimeo" 193Request a mounted file system to suspend write operations. 194All new write operations to the file system are stopped. 195After all write operations in progress have completed, the 196file system is synced to disk and the function returns. 197If the file system is currently suspended the 198.Xr sleep 9 199flag and timeout are specified by the arguments 200.Fa slpflag 201and 202.Fa slptimeo 203respectively. 204If 205.Fa slptimeo 206is less than zero 207.Er EWOULDBLOCK 208is returned. 209If the operation is successful, zero is returned, otherwise an 210appropriate error code is returned. 211.It Fn vfs_write_resume "mp" 212Request a mounted file system to resume write operations. 213.El 214.Sh CODE REFERENCES 215This section describes places within the 216.Nx 217source tree where actual code implementing or using the vfs 218operations can be found. 219All pathnames are relative to 220.Pa /usr/src . 221.Pp 222The vfs interface functions are implemented within the files 223.Pa sys/kern/vfs_subr.c 224and 225.Pa sys/kern/vfs_init.c . 226.Sh SEE ALSO 227.Xr intro 9 , 228.Xr namei 9 , 229.Xr vfs 9 , 230.Xr vfsops 9 , 231.Xr vnode 9 , 232.Xr vnodeops 9 233