233 lines
7.2 KiB
Groff
233 lines
7.2 KiB
Groff
.\" $NetBSD: vfssubr.9,v 1.10 2004/04/21 01:05:35 christos Exp $
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.\"
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.\" Copyright (c) 2003 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Gregory McGarry.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd January 10, 2004
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.Dt VFSSUBR 9
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.Os
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.Sh NAME
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.Nm vfssubr ,
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.Nm vfs_getnewfsid ,
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.Nm vfs_getvfs ,
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.Nm vfs_export ,
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.Nm vfs_showexport ,
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.Nm vfs_export_lookup ,
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.Nm vfs_setpublicfs ,
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.Nm vfs_mountedon ,
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.Nm vfs_mountroot ,
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.Nm vfs_unmountall ,
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.Nm vfs_busy ,
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.Nm vfs_unbusy ,
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.Nm vfs_rootmountalloc ,
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.Nm vfs_shutdown ,
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.Nm vfs_attach ,
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.Nm vfs_detach ,
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.Nm vfs_reinit ,
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.Nm vfs_getopsbyname ,
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.Nm vfs_write_suspend ,
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.Nm vfs_write_resume
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.Nd high-level interface to kernel file system interface
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/mount.h
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.In sys/vnode.h
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.Ft void
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.Fn vfs_getnewfsid "struct mount *mp"
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.Ft struct mount *
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.Fn vfs_getvfs "fsid_t *fsid"
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.Ft int
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.Fn vfs_export "struct mount *mp" "struct netexport *nep" \
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"struct export_args *argp"
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.Ft void
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.Fn vfs_showexport "struct mount *mp" "struct export_args *argp" \
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"struct netexport *nep"
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.Ft int
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.Fn vfs_export_lookup "struct mount *mp" "struct netexport *nep" \
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"struct export_args *argp"
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.Ft int
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.Fn vfs_setpublicfs "struct mount *mp" "struct netexport *nep" \
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"struct export_args *argp"
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.Ft int
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.Fn vfs_mountedon "struct vnode *vp"
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.Ft int
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.Fn vfs_mountroot "void"
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.Ft void
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.Fn vfs_unmountall "struct proc *p"
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.Ft int
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.Fn vfs_busy "struct mount *mp" "int flags" "struct simplelock *interlkp"
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.Ft void
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.Fn vfs_unbusy "struct mount *mp"
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.Ft int
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.Fn vfs_rootmountalloc "char *fstypename" "char *devname" \
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"struct mount **mpp"
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.Ft void
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.Fn vfs_shutdown "void"
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.Ft int
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.Fn vfs_attach "struct vfsops *vfs"
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.Ft int
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.Fn vfs_detach "struct vfsops *vfs"
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.Ft void
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.Fn vfs_reinit "void"
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.Ft struct vfsops *
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.Fn vfs_getopsbyname "const char *name"
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.Ft int
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.Fn vfs_write_suspend "struct mount *mp" "int slpflag" "int slptimeo"
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.Ft void
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.Fn vfs_write_resume "struct mount *mp"
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.Sh DESCRIPTION
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The high-level functions described in this page are the interface to
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the kernel file system interface (VFS).
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.Sh FUNCTIONS
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.Bl -tag -width compact
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.It Fn vfs_getnewfsid "mp"
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Get a new unique file system id type for the file system specified by
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the mount structure
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.Fa mp .
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The file system id type is stored in
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.Em mp-\*[Gt]mnt_stat.f_fsidx .
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.It Fn vfs_getvfs "fsid"
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Lookup a mount point with the file system identifier
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.Fa fsid .
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.It Fn vfs_export "mp" "nep" "argp"
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Undocumented.
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.It Fn vfs_showexport "mp" "argp" "nep"
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Undocumented.
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.It Fn vfs_export_lookup "mp" "nep" "argp"
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Check client permission on the exportable file system specified by the
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mount structure
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.Fa mp .
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The argument
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.Fa nam
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is the address of the networked client.
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This function is used by file system type specific functions to verify
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that the client can access the file system.
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.It Fn vfs_setpublicfs "mp" "nep" "argp"
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Set the publicly exported file system specified by the mount structure
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.Fa mp .
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.It Fn vfs_mountedon "vp"
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Check to see if a file system is mounted on a block device specified
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by the vnode
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.Fa vp .
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.It Fn vfs_mountroot "void"
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Mount the root file system.
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.It Fn vfs_unmountall "p"
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Unmount all file systems.
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.It Fn vfs_busy "mp" "flags" "interlkp"
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Mark the mount point specified by
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.Fa mp
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as busy.
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This function is used to synchronize access and to delay unmounting.
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The interlock specified by argument
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.Fa interlkp
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is not released on failure.
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.It Fn vfs_unbusy "mp"
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Free the busy file system specified by the mount structure
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.Fa mp .
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.It Fn vfs_rootmountalloc "fstypename" "devname" "mpp"
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Lookup a file system type specified by the name
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.Fa fstypename
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and if found allocate and initialise a mount structure for it.
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The allocated mount structure is returned in the address specified by
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.Fa mpp .
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The device the root file system was mounted from is specified by the
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argument
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.Fa devname
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and is recorded in the new mount structure.
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.It Fn vfs_shutdown
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Sync and unmount all file systems before shutting down.
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Invoked by
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.Xr cpu_reboot 9 .
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.It Fn vfs_attach "vfs"
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Establish file system
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.Fa vfs
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and initialise it.
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.It Fn vfs_detach "vfs"
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Remove file system
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.Fa vfs
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from the kernel.
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.It Fn vfs_reinit "void"
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Reinitialises all file systems within the kernel through file
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system-specific vfs operation (see
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.Xr vfsops 9 ) .
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.It Fn vfs_getopsbyname "name"
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Given a file system name specified by
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.Fa name ,
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look up the vfs operations for that file system (see
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.Xr vfsops 9 ) ,
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or return
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.Dv NULL
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if file system isn't present in the kernel.
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.It Fn vfs_write_suspend "mp" "slpflag" "slptimeo"
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Request a mounted file system to suspend write operations.
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All new write operations to the file system are stopped.
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After all write operations in progress have completed, the
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file system is synced to disk and the function returns.
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If the file system is currently suspended the
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.Xr sleep 9
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flag and timeout are specified by the arguments
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.Fa slpflag
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and
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.Fa slptimeo
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respectively.
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If
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.Fa slptimeo
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is less than zero
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.Er EWOULDBLOCK
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is returned.
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If the operation is successful, zero is returned, otherwise an
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appropriate error code is returned.
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.It Fn vfs_write_resume "mp"
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Request a mounted file system to resume write operations.
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.El
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.Sh CODE REFERENCES
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This section describes places within the
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.Nx
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source tree where actual code implementing or using the vfs
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operations can be found.
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All pathnames are relative to
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.Pa /usr/src .
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.Pp
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The vfs interface functions are implemented within the files
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.Pa sys/kern/vfs_subr.c
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and
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.Pa sys/kern/vfs_init.c .
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.Sh SEE ALSO
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.Xr intro 9 ,
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.Xr namei 9 ,
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.Xr vfs 9 ,
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.Xr vfsops 9 ,
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.Xr vnode 9 ,
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.Xr vnodeops 9
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