373 lines
10 KiB
C
373 lines
10 KiB
C
/*-
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed
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* to Berkeley by John Heidemann of the UCLA Ficus project.
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*
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* Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
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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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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vfs_init.c 8.3 (Berkeley) 1/4/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/fnv_hash.h>
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#include <sys/kernel.h>
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#include <sys/linker.h>
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#include <sys/mount.h>
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#include <sys/proc.h>
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#include <sys/sx.h>
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#include <sys/syscallsubr.h>
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#include <sys/sysctl.h>
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#include <sys/vnode.h>
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#include <sys/malloc.h>
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static int vfs_register(struct vfsconf *);
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static int vfs_unregister(struct vfsconf *);
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MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
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/*
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* The highest defined VFS number.
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*/
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int maxvfsconf = VFS_GENERIC + 1;
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/*
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* Single-linked list of configured VFSes.
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* New entries are added/deleted by vfs_register()/vfs_unregister()
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*/
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struct vfsconfhead vfsconf = TAILQ_HEAD_INITIALIZER(vfsconf);
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struct sx vfsconf_sx;
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SX_SYSINIT(vfsconf, &vfsconf_sx, "vfsconf");
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/*
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* Loader.conf variable vfs.typenumhash enables setting vfc_typenum using a hash
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* calculation on vfc_name, so that it doesn't change when file systems are
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* loaded in a different order. This will avoid the NFS server file handles from
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* changing for file systems that use vfc_typenum in their fsid.
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*/
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static int vfs_typenumhash = 1;
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SYSCTL_INT(_vfs, OID_AUTO, typenumhash, CTLFLAG_RDTUN, &vfs_typenumhash, 0,
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"Set vfc_typenum using a hash calculation on vfc_name, so that it does not"
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"change when file systems are loaded in a different order.");
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/*
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* A Zen vnode attribute structure.
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*
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* Initialized when the first filesystem registers by vfs_register().
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*/
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struct vattr va_null;
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/*
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* vfs_init.c
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*
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* Allocate and fill in operations vectors.
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*
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* An undocumented feature of this approach to defining operations is that
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* there can be multiple entries in vfs_opv_descs for the same operations
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* vector. This allows third parties to extend the set of operations
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* supported by another layer in a binary compatibile way. For example,
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* assume that NFS needed to be modified to support Ficus. NFS has an entry
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* (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
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* default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
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* listing those new operations Ficus adds to NFS, all without modifying the
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* NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
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* that is a(whole)nother story.) This is a feature.
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*/
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/*
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* Routines having to do with the management of the vnode table.
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*/
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static struct vfsconf *
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vfs_byname_locked(const char *name)
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{
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struct vfsconf *vfsp;
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sx_assert(&vfsconf_sx, SA_LOCKED);
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if (!strcmp(name, "ffs"))
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name = "ufs";
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TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
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if (!strcmp(name, vfsp->vfc_name))
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return (vfsp);
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}
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return (NULL);
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}
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struct vfsconf *
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vfs_byname(const char *name)
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{
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struct vfsconf *vfsp;
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vfsconf_slock();
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vfsp = vfs_byname_locked(name);
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vfsconf_sunlock();
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return (vfsp);
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}
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struct vfsconf *
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vfs_byname_kld(const char *fstype, struct thread *td, int *error)
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{
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struct vfsconf *vfsp;
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int fileid, loaded;
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vfsp = vfs_byname(fstype);
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if (vfsp != NULL)
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return (vfsp);
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/* Try to load the respective module. */
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*error = kern_kldload(td, fstype, &fileid);
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loaded = (*error == 0);
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if (*error == EEXIST)
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*error = 0;
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if (*error)
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return (NULL);
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/* Look up again to see if the VFS was loaded. */
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vfsp = vfs_byname(fstype);
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if (vfsp == NULL) {
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if (loaded)
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(void)kern_kldunload(td, fileid, LINKER_UNLOAD_FORCE);
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*error = ENODEV;
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return (NULL);
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}
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return (vfsp);
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}
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/* Register a new filesystem type in the global table */
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static int
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vfs_register(struct vfsconf *vfc)
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{
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struct sysctl_oid *oidp;
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struct vfsops *vfsops;
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static int once;
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struct vfsconf *tvfc;
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uint32_t hashval;
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int secondpass;
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if (!once) {
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vattr_null(&va_null);
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once = 1;
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}
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if (vfc->vfc_version != VFS_VERSION) {
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printf("ERROR: filesystem %s, unsupported ABI version %x\n",
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vfc->vfc_name, vfc->vfc_version);
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return (EINVAL);
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}
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vfsconf_lock();
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if (vfs_byname_locked(vfc->vfc_name) != NULL) {
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vfsconf_unlock();
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return (EEXIST);
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}
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if (vfs_typenumhash != 0) {
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/*
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* Calculate a hash on vfc_name to use for vfc_typenum. Unless
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* all of 1<->255 are assigned, it is limited to 8bits since
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* that is what ZFS uses from vfc_typenum and is also the
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* preferred range for vfs_getnewfsid().
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*/
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hashval = fnv_32_str(vfc->vfc_name, FNV1_32_INIT);
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hashval &= 0xff;
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secondpass = 0;
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do {
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/* Look for and fix any collision. */
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TAILQ_FOREACH(tvfc, &vfsconf, vfc_list) {
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if (hashval == tvfc->vfc_typenum) {
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if (hashval == 255 && secondpass == 0) {
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hashval = 1;
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secondpass = 1;
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} else
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hashval++;
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break;
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}
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}
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} while (tvfc != NULL);
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vfc->vfc_typenum = hashval;
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if (vfc->vfc_typenum >= maxvfsconf)
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maxvfsconf = vfc->vfc_typenum + 1;
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} else
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vfc->vfc_typenum = maxvfsconf++;
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TAILQ_INSERT_TAIL(&vfsconf, vfc, vfc_list);
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/*
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* Initialise unused ``struct vfsops'' fields, to use
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* the vfs_std*() functions. Note, we need the mount
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* and unmount operations, at the least. The check
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* for vfsops available is just a debugging aid.
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*/
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KASSERT(vfc->vfc_vfsops != NULL,
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("Filesystem %s has no vfsops", vfc->vfc_name));
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/*
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* Check the mount and unmount operations.
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*/
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vfsops = vfc->vfc_vfsops;
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KASSERT(vfsops->vfs_mount != NULL,
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("Filesystem %s has no mount op", vfc->vfc_name));
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KASSERT(vfsops->vfs_unmount != NULL,
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("Filesystem %s has no unmount op", vfc->vfc_name));
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if (vfsops->vfs_root == NULL)
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/* return file system's root vnode */
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vfsops->vfs_root = vfs_stdroot;
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if (vfsops->vfs_quotactl == NULL)
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/* quota control */
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vfsops->vfs_quotactl = vfs_stdquotactl;
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if (vfsops->vfs_statfs == NULL)
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/* return file system's status */
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vfsops->vfs_statfs = vfs_stdstatfs;
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if (vfsops->vfs_sync == NULL)
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/*
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* flush unwritten data (nosync)
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* file systems can use vfs_stdsync
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* explicitly by setting it in the
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* vfsop vector.
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*/
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vfsops->vfs_sync = vfs_stdnosync;
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if (vfsops->vfs_vget == NULL)
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/* convert an inode number to a vnode */
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vfsops->vfs_vget = vfs_stdvget;
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if (vfsops->vfs_fhtovp == NULL)
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/* turn an NFS file handle into a vnode */
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vfsops->vfs_fhtovp = vfs_stdfhtovp;
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if (vfsops->vfs_checkexp == NULL)
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/* check if file system is exported */
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vfsops->vfs_checkexp = vfs_stdcheckexp;
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if (vfsops->vfs_init == NULL)
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/* file system specific initialisation */
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vfsops->vfs_init = vfs_stdinit;
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if (vfsops->vfs_uninit == NULL)
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/* file system specific uninitialisation */
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vfsops->vfs_uninit = vfs_stduninit;
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if (vfsops->vfs_extattrctl == NULL)
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/* extended attribute control */
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vfsops->vfs_extattrctl = vfs_stdextattrctl;
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if (vfsops->vfs_sysctl == NULL)
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vfsops->vfs_sysctl = vfs_stdsysctl;
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/*
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* Call init function for this VFS...
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*/
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(*(vfc->vfc_vfsops->vfs_init))(vfc);
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vfsconf_unlock();
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/*
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* If this filesystem has a sysctl node under vfs
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* (i.e. vfs.xxfs), then change the oid number of that node to
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* match the filesystem's type number. This allows user code
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* which uses the type number to read sysctl variables defined
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* by the filesystem to continue working. Since the oids are
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* in a sorted list, we need to make sure the order is
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* preserved by re-registering the oid after modifying its
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* number.
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*/
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sysctl_xlock();
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SLIST_FOREACH(oidp, SYSCTL_CHILDREN(&sysctl___vfs), oid_link) {
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if (strcmp(oidp->oid_name, vfc->vfc_name) == 0) {
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sysctl_unregister_oid(oidp);
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oidp->oid_number = vfc->vfc_typenum;
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sysctl_register_oid(oidp);
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break;
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}
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}
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sysctl_xunlock();
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return (0);
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}
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/* Remove registration of a filesystem type */
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static int
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vfs_unregister(struct vfsconf *vfc)
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{
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struct vfsconf *vfsp;
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int error, i, maxtypenum;
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i = vfc->vfc_typenum;
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vfsconf_lock();
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vfsp = vfs_byname_locked(vfc->vfc_name);
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if (vfsp == NULL) {
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vfsconf_unlock();
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return (EINVAL);
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}
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if (vfsp->vfc_refcount != 0) {
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vfsconf_unlock();
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return (EBUSY);
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}
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if (vfc->vfc_vfsops->vfs_uninit != NULL) {
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error = (*vfc->vfc_vfsops->vfs_uninit)(vfsp);
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if (error != 0) {
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vfsconf_unlock();
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return (error);
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}
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}
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TAILQ_REMOVE(&vfsconf, vfsp, vfc_list);
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maxtypenum = VFS_GENERIC;
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TAILQ_FOREACH(vfsp, &vfsconf, vfc_list)
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if (maxtypenum < vfsp->vfc_typenum)
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maxtypenum = vfsp->vfc_typenum;
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maxvfsconf = maxtypenum + 1;
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vfsconf_unlock();
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return (0);
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}
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/*
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* Standard kernel module handling code for filesystem modules.
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* Referenced from VFS_SET().
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*/
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int
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vfs_modevent(module_t mod, int type, void *data)
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{
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struct vfsconf *vfc;
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int error = 0;
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vfc = (struct vfsconf *)data;
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switch (type) {
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case MOD_LOAD:
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if (vfc)
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error = vfs_register(vfc);
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break;
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case MOD_UNLOAD:
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if (vfc)
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error = vfs_unregister(vfc);
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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