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NetBSD/sys/kern/vfs_mount.c

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/* $NetBSD: vfs_mount.c,v 1.104 2024/01/17 10:17:29 hannken Exp $ */
/*-
* Copyright (c) 1997-2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center, by Charles M. Hannum, and by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.104 2024/01/17 10:17:29 hannken Exp $");
#include "veriexec.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/atomic.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/filedesc.h>
#include <sys/device.h>
#include <sys/kauth.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/fstrans.h>
#include <sys/namei.h>
#include <sys/extattr.h>
#include <sys/verified_exec.h>
#include <sys/syscallargs.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/vfs_syscalls.h>
#include <sys/vnode_impl.h>
#include <miscfs/deadfs/deadfs.h>
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
#include <uvm/uvm_swap.h>
enum mountlist_type {
ME_MOUNT,
ME_MARKER
};
struct mountlist_entry {
TAILQ_ENTRY(mountlist_entry) me_list; /* Mount list. */
struct mount *me_mount; /* Actual mount if ME_MOUNT,
current mount else. */
enum mountlist_type me_type; /* Mount or marker. */
};
struct mount_iterator {
struct mountlist_entry mi_entry;
};
static struct vnode *vfs_vnode_iterator_next1(struct vnode_iterator *,
bool (*)(void *, struct vnode *), void *, bool);
/* Root filesystem. */
vnode_t * rootvnode;
/* Mounted filesystem list. */
static TAILQ_HEAD(mountlist, mountlist_entry) mountlist;
static kmutex_t mountlist_lock __cacheline_aligned;
int vnode_offset_next_by_lru /* XXX: ugly hack for pstat.c */
= offsetof(vnode_impl_t, vi_lrulist.tqe_next);
kmutex_t vfs_list_lock __cacheline_aligned;
static specificdata_domain_t mount_specificdata_domain;
static kmutex_t mntid_lock;
static kmutex_t mountgen_lock __cacheline_aligned;
static uint64_t mountgen;
void
vfs_mount_sysinit(void)
{
TAILQ_INIT(&mountlist);
mutex_init(&mountlist_lock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&vfs_list_lock, MUTEX_DEFAULT, IPL_NONE);
mount_specificdata_domain = specificdata_domain_create();
mutex_init(&mntid_lock, MUTEX_DEFAULT, IPL_NONE);
mutex_init(&mountgen_lock, MUTEX_DEFAULT, IPL_NONE);
mountgen = 0;
}
struct mount *
vfs_mountalloc(struct vfsops *vfsops, vnode_t *vp)
{
struct mount *mp;
int error __diagused;
mp = kmem_zalloc(sizeof(*mp), KM_SLEEP);
mp->mnt_op = vfsops;
mp->mnt_refcnt = 1;
TAILQ_INIT(&mp->mnt_vnodelist);
mp->mnt_renamelock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
mp->mnt_vnodelock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
mp->mnt_updating = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
mp->mnt_vnodecovered = vp;
mount_initspecific(mp);
error = fstrans_mount(mp);
KASSERT(error == 0);
mutex_enter(&mountgen_lock);
mp->mnt_gen = mountgen++;
mutex_exit(&mountgen_lock);
return mp;
}
/*
* vfs_rootmountalloc: lookup a filesystem type, and if found allocate and
* initialize a mount structure for it.
*
* Devname is usually updated by mount(8) after booting.
*/
int
vfs_rootmountalloc(const char *fstypename, const char *devname,
struct mount **mpp)
{
struct vfsops *vfsp = NULL;
struct mount *mp;
int error __diagused;
mutex_enter(&vfs_list_lock);
LIST_FOREACH(vfsp, &vfs_list, vfs_list)
if (!strncmp(vfsp->vfs_name, fstypename,
sizeof(mp->mnt_stat.f_fstypename)))
break;
if (vfsp == NULL) {
mutex_exit(&vfs_list_lock);
return (ENODEV);
}
vfsp->vfs_refcount++;
mutex_exit(&vfs_list_lock);
if ((mp = vfs_mountalloc(vfsp, NULL)) == NULL)
return ENOMEM;
error = vfs_busy(mp);
KASSERT(error == 0);
mp->mnt_flag = MNT_RDONLY;
(void)strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfs_name,
sizeof(mp->mnt_stat.f_fstypename));
mp->mnt_stat.f_mntonname[0] = '/';
mp->mnt_stat.f_mntonname[1] = '\0';
mp->mnt_stat.f_mntfromname[sizeof(mp->mnt_stat.f_mntfromname) - 1] =
'\0';
(void)copystr(devname, mp->mnt_stat.f_mntfromname,
sizeof(mp->mnt_stat.f_mntfromname) - 1, 0);
*mpp = mp;
return 0;
}
/*
* vfs_getnewfsid: get a new unique fsid.
*/
void
vfs_getnewfsid(struct mount *mp)
{
static u_short xxxfs_mntid;
struct mountlist_entry *me;
fsid_t tfsid;
int mtype;
mutex_enter(&mntid_lock);
if (xxxfs_mntid == 0)
++xxxfs_mntid;
mtype = makefstype(mp->mnt_op->vfs_name);
tfsid.__fsid_val[0] = makedev(mtype & 0xff, xxxfs_mntid);
tfsid.__fsid_val[1] = mtype;
/* Always increment to not return the same fsid to parallel mounts. */
xxxfs_mntid++;
/*
* Directly walk mountlist to prevent deadlock through
* mountlist_iterator_next() -> vfs_busy().
*/
mutex_enter(&mountlist_lock);
for (me = TAILQ_FIRST(&mountlist); me != TAILQ_END(&mountlist); ) {
if (me->me_type == ME_MOUNT &&
me->me_mount->mnt_stat.f_fsidx.__fsid_val[0] ==
tfsid.__fsid_val[0] &&
me->me_mount->mnt_stat.f_fsidx.__fsid_val[1] ==
tfsid.__fsid_val[1]) {
tfsid.__fsid_val[0]++;
xxxfs_mntid++;
me = TAILQ_FIRST(&mountlist);
} else {
me = TAILQ_NEXT(me, me_list);
}
}
mutex_exit(&mountlist_lock);
mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0];
mp->mnt_stat.f_fsidx.__fsid_val[1] = tfsid.__fsid_val[1];
mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
mutex_exit(&mntid_lock);
}
/*
* Lookup a mount point by filesystem identifier.
*
* XXX Needs to add a reference to the mount point.
*/
struct mount *
vfs_getvfs(fsid_t *fsid)
{
mount_iterator_t *iter;
struct mount *mp;
mountlist_iterator_init(&iter);
while ((mp = mountlist_iterator_next(iter)) != NULL) {
if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] &&
mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) {
mountlist_iterator_destroy(iter);
return mp;
}
}
mountlist_iterator_destroy(iter);
return NULL;
}
/*
* Take a reference to a mount structure.
*/
void
vfs_ref(struct mount *mp)
{
KASSERT(mp->mnt_refcnt > 0 || mutex_owned(&mountlist_lock));
atomic_inc_uint(&mp->mnt_refcnt);
}
/*
* Drop a reference to a mount structure, freeing if the last reference.
*/
void
vfs_rele(struct mount *mp)
{
membar_release();
if (__predict_true((int)atomic_dec_uint_nv(&mp->mnt_refcnt) > 0)) {
return;
}
membar_acquire();
/*
* Nothing else has visibility of the mount: we can now
* free the data structures.
*/
KASSERT(mp->mnt_refcnt == 0);
specificdata_fini(mount_specificdata_domain, &mp->mnt_specdataref);
mutex_obj_free(mp->mnt_updating);
mutex_obj_free(mp->mnt_renamelock);
mutex_obj_free(mp->mnt_vnodelock);
if (mp->mnt_op != NULL) {
vfs_delref(mp->mnt_op);
}
fstrans_unmount(mp);
/*
* Final free of mp gets done from fstrans_mount_dtor().
*
* Prevents this memory to be reused as a mount before
* fstrans releases all references to it.
*/
}
/*
* Mark a mount point as busy, and gain a new reference to it. Used to
* prevent the file system from being unmounted during critical sections.
*
* vfs_busy can be called multiple times and by multiple threads
* and must be accompanied by the same number of vfs_unbusy calls.
*
* => The caller must hold a pre-existing reference to the mount.
* => Will fail if the file system is being unmounted, or is unmounted.
*/
static inline int
_vfs_busy(struct mount *mp, bool wait)
{
KASSERT(mp->mnt_refcnt > 0);
if (wait) {
fstrans_start(mp);
} else {
if (fstrans_start_nowait(mp))
return EBUSY;
}
if (__predict_false((mp->mnt_iflag & IMNT_GONE) != 0)) {
fstrans_done(mp);
return ENOENT;
}
vfs_ref(mp);
return 0;
}
int
vfs_busy(struct mount *mp)
{
return _vfs_busy(mp, true);
}
int
vfs_trybusy(struct mount *mp)
{
return _vfs_busy(mp, false);
}
/*
* Unbusy a busy filesystem.
*
* Every successful vfs_busy() call must be undone by a vfs_unbusy() call.
*/
void
vfs_unbusy(struct mount *mp)
{
KASSERT(mp->mnt_refcnt > 0);
fstrans_done(mp);
vfs_rele(mp);
}
/*
* Change a file systems lower mount.
* Both the current and the new lower mount may be NULL. The caller
* guarantees exclusive access to the mount and holds a pre-existing
* reference to the new lower mount.
*/
int
vfs_set_lowermount(struct mount *mp, struct mount *lowermp)
{
struct mount *oldlowermp;
int error;
#ifdef DEBUG
/*
* Limit the depth of file system stack so kernel sanitizers
* may stress mount/unmount without exhausting the kernel stack.
*/
int depth;
struct mount *mp2;
for (depth = 0, mp2 = lowermp; mp2; depth++, mp2 = mp2->mnt_lower) {
if (depth == 23)
return EINVAL;
}
#endif
if (lowermp) {
if (lowermp == dead_rootmount)
return ENOENT;
error = vfs_busy(lowermp);
if (error)
return error;
vfs_ref(lowermp);
}
oldlowermp = mp->mnt_lower;
mp->mnt_lower = lowermp;
if (lowermp)
vfs_unbusy(lowermp);
if (oldlowermp)
vfs_rele(oldlowermp);
return 0;
}
struct vnode_iterator {
vnode_impl_t vi_vnode;
};
void
vfs_vnode_iterator_init(struct mount *mp, struct vnode_iterator **vnip)
{
vnode_t *vp;
vnode_impl_t *vip;
vp = vnalloc_marker(mp);
vip = VNODE_TO_VIMPL(vp);
mutex_enter(mp->mnt_vnodelock);
TAILQ_INSERT_HEAD(&mp->mnt_vnodelist, vip, vi_mntvnodes);
vp->v_usecount = 1;
mutex_exit(mp->mnt_vnodelock);
*vnip = (struct vnode_iterator *)vip;
}
void
vfs_vnode_iterator_destroy(struct vnode_iterator *vni)
{
vnode_impl_t *mvip = &vni->vi_vnode;
vnode_t *mvp = VIMPL_TO_VNODE(mvip);
kmutex_t *lock;
KASSERT(vnis_marker(mvp));
if (vrefcnt(mvp) != 0) {
lock = mvp->v_mount->mnt_vnodelock;
mutex_enter(lock);
TAILQ_REMOVE(&mvp->v_mount->mnt_vnodelist, mvip, vi_mntvnodes);
mvp->v_usecount = 0;
mutex_exit(lock);
}
vnfree_marker(mvp);
}
static struct vnode *
vfs_vnode_iterator_next1(struct vnode_iterator *vni,
bool (*f)(void *, struct vnode *), void *cl, bool do_wait)
{
vnode_impl_t *mvip = &vni->vi_vnode;
struct mount *mp = VIMPL_TO_VNODE(mvip)->v_mount;
vnode_t *vp;
vnode_impl_t *vip;
kmutex_t *lock;
int error;
KASSERT(vnis_marker(VIMPL_TO_VNODE(mvip)));
lock = mp->mnt_vnodelock;
do {
mutex_enter(lock);
vip = TAILQ_NEXT(mvip, vi_mntvnodes);
TAILQ_REMOVE(&mp->mnt_vnodelist, mvip, vi_mntvnodes);
VIMPL_TO_VNODE(mvip)->v_usecount = 0;
again:
if (vip == NULL) {
mutex_exit(lock);
return NULL;
}
vp = VIMPL_TO_VNODE(vip);
KASSERT(vp != NULL);
mutex_enter(vp->v_interlock);
if (vnis_marker(vp) ||
vdead_check(vp, (do_wait ? 0 : VDEAD_NOWAIT)) ||
(f && !(*f)(cl, vp))) {
mutex_exit(vp->v_interlock);
vip = TAILQ_NEXT(vip, vi_mntvnodes);
goto again;
}
TAILQ_INSERT_AFTER(&mp->mnt_vnodelist, vip, mvip, vi_mntvnodes);
VIMPL_TO_VNODE(mvip)->v_usecount = 1;
mutex_exit(lock);
error = vcache_vget(vp);
KASSERT(error == 0 || error == ENOENT);
} while (error != 0);
return vp;
}
struct vnode *
vfs_vnode_iterator_next(struct vnode_iterator *vni,
bool (*f)(void *, struct vnode *), void *cl)
{
return vfs_vnode_iterator_next1(vni, f, cl, false);
}
/*
* Move a vnode from one mount queue to another.
*/
void
vfs_insmntque(vnode_t *vp, struct mount *mp)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
struct mount *omp;
kmutex_t *lock;
KASSERT(mp == NULL || (mp->mnt_iflag & IMNT_UNMOUNT) == 0 ||
vp->v_tag == VT_VFS);
/*
* Delete from old mount point vnode list, if on one.
*/
if ((omp = vp->v_mount) != NULL) {
lock = omp->mnt_vnodelock;
mutex_enter(lock);
TAILQ_REMOVE(&vp->v_mount->mnt_vnodelist, vip, vi_mntvnodes);
mutex_exit(lock);
}
/*
* Insert into list of vnodes for the new mount point, if
* available. The caller must take a reference on the mount
* structure and donate to the vnode.
*/
if ((vp->v_mount = mp) != NULL) {
lock = mp->mnt_vnodelock;
mutex_enter(lock);
TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vip, vi_mntvnodes);
mutex_exit(lock);
}
if (omp != NULL) {
/* Release reference to old mount. */
vfs_rele(omp);
}
}
/*
* Remove any vnodes in the vnode table belonging to mount point mp.
*
* If FORCECLOSE is not specified, there should not be any active ones,
* return error if any are found (nb: this is a user error, not a
* system error). If FORCECLOSE is specified, detach any active vnodes
* that are found.
*
* If WRITECLOSE is set, only flush out regular file vnodes open for
* writing.
*
* SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
*/
#ifdef DEBUG
int busyprt = 0; /* print out busy vnodes */
struct ctldebug debug1 = { "busyprt", &busyprt };
#endif
static vnode_t *
vflushnext(struct vnode_iterator *marker, int *when)
{
if (getticks() > *when) {
yield();
*when = getticks() + hz / 10;
}
preempt_point();
return vfs_vnode_iterator_next1(marker, NULL, NULL, true);
}
/*
* Flush one vnode. Referenced on entry, unreferenced on return.
*/
static int
vflush_one(vnode_t *vp, vnode_t *skipvp, int flags)
{
int error;
struct vattr vattr;
if (vp == skipvp ||
((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM))) {
vrele(vp);
return 0;
}
/*
* If WRITECLOSE is set, only flush out regular file
* vnodes open for writing or open and unlinked.
*/
if ((flags & WRITECLOSE)) {
if (vp->v_type != VREG) {
vrele(vp);
return 0;
}
error = vn_lock(vp, LK_EXCLUSIVE);
if (error) {
KASSERT(error == ENOENT);
vrele(vp);
return 0;
}
error = VOP_FSYNC(vp, curlwp->l_cred, FSYNC_WAIT, 0, 0);
if (error == 0)
error = VOP_GETATTR(vp, &vattr, curlwp->l_cred);
VOP_UNLOCK(vp);
if (error) {
vrele(vp);
return error;
}
if (vp->v_writecount == 0 && vattr.va_nlink > 0) {
vrele(vp);
return 0;
}
}
/*
* First try to recycle the vnode.
*/
if (vrecycle(vp))
return 0;
/*
* If FORCECLOSE is set, forcibly close the vnode.
* For block or character devices, revert to an
* anonymous device. For all other files, just
* kill them.
*/
if (flags & FORCECLOSE) {
if (vrefcnt(vp) > 1 &&
(vp->v_type == VBLK || vp->v_type == VCHR))
vcache_make_anon(vp);
else
vgone(vp);
return 0;
}
vrele(vp);
return EBUSY;
}
int
vflush(struct mount *mp, vnode_t *skipvp, int flags)
{
vnode_t *vp;
struct vnode_iterator *marker;
int busy, error, when, retries = 2;
do {
busy = error = when = 0;
/*
* First, flush out any vnode references from the
* deferred vrele list.
*/
vrele_flush(mp);
vfs_vnode_iterator_init(mp, &marker);
while ((vp = vflushnext(marker, &when)) != NULL) {
error = vflush_one(vp, skipvp, flags);
if (error == EBUSY) {
error = 0;
busy++;
#ifdef DEBUG
if (busyprt && retries == 0)
vprint("vflush: busy vnode", vp);
#endif
} else if (error != 0) {
break;
}
}
vfs_vnode_iterator_destroy(marker);
} while (error == 0 && busy > 0 && retries-- > 0);
if (error)
return error;
if (busy)
return EBUSY;
return 0;
}
/*
* Mount a file system.
*/
/*
* Scan all active processes to see if any of them have a current or root
* directory onto which the new filesystem has just been mounted. If so,
* replace them with the new mount point.
*/
static void
mount_checkdirs(vnode_t *olddp)
{
vnode_t *newdp, *rele1, *rele2;
struct cwdinfo *cwdi;
struct proc *p;
bool retry;
if (vrefcnt(olddp) == 1) {
return;
}
if (VFS_ROOT(olddp->v_mountedhere, LK_EXCLUSIVE, &newdp))
panic("mount: lost mount");
do {
retry = false;
mutex_enter(&proc_lock);
PROCLIST_FOREACH(p, &allproc) {
if ((cwdi = p->p_cwdi) == NULL)
continue;
/*
* Cannot change to the old directory any more,
* so even if we see a stale value it is not a
* problem.
*/
if (cwdi->cwdi_cdir != olddp &&
cwdi->cwdi_rdir != olddp)
continue;
retry = true;
rele1 = NULL;
rele2 = NULL;
atomic_inc_uint(&cwdi->cwdi_refcnt);
mutex_exit(&proc_lock);
rw_enter(&cwdi->cwdi_lock, RW_WRITER);
if (cwdi->cwdi_cdir == olddp) {
rele1 = cwdi->cwdi_cdir;
vref(newdp);
cwdi->cwdi_cdir = newdp;
}
if (cwdi->cwdi_rdir == olddp) {
rele2 = cwdi->cwdi_rdir;
vref(newdp);
cwdi->cwdi_rdir = newdp;
}
rw_exit(&cwdi->cwdi_lock);
cwdfree(cwdi);
if (rele1 != NULL)
vrele(rele1);
if (rele2 != NULL)
vrele(rele2);
mutex_enter(&proc_lock);
break;
}
mutex_exit(&proc_lock);
} while (retry);
if (rootvnode == olddp) {
vrele(rootvnode);
vref(newdp);
rootvnode = newdp;
}
vput(newdp);
}
/*
* Start extended attributes
*/
static int
start_extattr(struct mount *mp)
{
int error;
error = VFS_EXTATTRCTL(mp, EXTATTR_CMD_START, NULL, 0, NULL);
if (error)
printf("%s: failed to start extattr: error = %d\n",
mp->mnt_stat.f_mntonname, error);
return error;
}
int
mount_domount(struct lwp *l, vnode_t **vpp, struct vfsops *vfsops,
const char *path, int flags, void *data, size_t *data_len)
{
vnode_t *vp = *vpp;
struct mount *mp;
struct pathbuf *pb;
struct nameidata nd;
int error, error2;
error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT,
KAUTH_REQ_SYSTEM_MOUNT_NEW, vp, KAUTH_ARG(flags), data);
if (error) {
vfs_delref(vfsops);
return error;
}
/* Cannot make a non-dir a mount-point (from here anyway). */
if (vp->v_type != VDIR) {
vfs_delref(vfsops);
return ENOTDIR;
}
if (flags & MNT_EXPORTED) {
vfs_delref(vfsops);
return EINVAL;
}
if ((mp = vfs_mountalloc(vfsops, vp)) == NULL) {
vfs_delref(vfsops);
return ENOMEM;
}
mp->mnt_stat.f_owner = kauth_cred_geteuid(l->l_cred);
/*
* The underlying file system may refuse the mount for
* various reasons. Allow the user to force it to happen.
*
* Set the mount level flags.
*/
mp->mnt_flag = flags & (MNT_BASIC_FLAGS | MNT_FORCE | MNT_IGNORE);
error = VFS_MOUNT(mp, path, data, data_len);
mp->mnt_flag &= ~MNT_OP_FLAGS;
if (error != 0) {
vfs_rele(mp);
return error;
}
/* Suspend new file system before taking mnt_updating. */
do {
error2 = vfs_suspend(mp, 0);
} while (error2 == EINTR || error2 == ERESTART);
KASSERT(error2 == 0 || error2 == EOPNOTSUPP);
mutex_enter(mp->mnt_updating);
/*
* Validate and prepare the mount point.
*/
error = pathbuf_copyin(path, &pb);
if (error != 0) {
goto err_mounted;
}
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb);
error = namei(&nd);
pathbuf_destroy(pb);
if (error != 0) {
goto err_mounted;
}
if (nd.ni_vp != vp) {
vput(nd.ni_vp);
error = EINVAL;
goto err_mounted;
}
if (vp->v_mountedhere != NULL) {
vput(nd.ni_vp);
error = EBUSY;
goto err_mounted;
}
error = vinvalbuf(vp, V_SAVE, l->l_cred, l, 0, 0);
if (error != 0) {
vput(nd.ni_vp);
goto err_mounted;
}
/*
* Put the new filesystem on the mount list after root.
*/
cache_purge(vp);
mp->mnt_iflag &= ~IMNT_WANTRDWR;
mountlist_append(mp);
if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0)
vfs_syncer_add_to_worklist(mp);
vp->v_mountedhere = mp;
vput(nd.ni_vp);
mount_checkdirs(vp);
mutex_exit(mp->mnt_updating);
if (error2 == 0)
vfs_resume(mp);
/* Hold an additional reference to the mount across VFS_START(). */
vfs_ref(mp);
(void) VFS_STATVFS(mp, &mp->mnt_stat);
error = VFS_START(mp, 0);
if (error) {
vrele(vp);
} else if (flags & MNT_EXTATTR) {
if (start_extattr(mp) != 0)
mp->mnt_flag &= ~MNT_EXTATTR;
}
/* Drop reference held for VFS_START(). */
vfs_rele(mp);
*vpp = NULL;
return error;
err_mounted:
if (VFS_UNMOUNT(mp, MNT_FORCE) != 0)
panic("Unmounting fresh file system failed");
mutex_exit(mp->mnt_updating);
if (error2 == 0)
vfs_resume(mp);
vfs_set_lowermount(mp, NULL);
vfs_rele(mp);
return error;
}
/*
* Do the actual file system unmount. File system is assumed to have
* been locked by the caller.
*
* => Caller hold reference to the mount, explicitly for dounmount().
*/
int
dounmount(struct mount *mp, int flags, struct lwp *l)
{
vnode_t *coveredvp, *vp;
int error, async, used_syncer, used_extattr;
const bool was_suspended = fstrans_is_owner(mp);
#if NVERIEXEC > 0
error = veriexec_unmountchk(mp);
if (error)
return (error);
#endif /* NVERIEXEC > 0 */
if (!was_suspended) {
error = vfs_suspend(mp, 0);
if (error) {
return error;
}
}
KASSERT((mp->mnt_iflag & IMNT_GONE) == 0);
used_syncer = (mp->mnt_iflag & IMNT_ONWORKLIST) != 0;
used_extattr = mp->mnt_flag & MNT_EXTATTR;
mp->mnt_iflag |= IMNT_UNMOUNT;
mutex_enter(mp->mnt_updating);
async = mp->mnt_flag & MNT_ASYNC;
mp->mnt_flag &= ~MNT_ASYNC;
cache_purgevfs(mp); /* remove cache entries for this file sys */
if (used_syncer)
vfs_syncer_remove_from_worklist(mp);
error = 0;
if (((mp->mnt_flag & MNT_RDONLY) == 0) && ((flags & MNT_FORCE) == 0)) {
error = VFS_SYNC(mp, MNT_WAIT, l->l_cred);
}
if (error == 0 || (flags & MNT_FORCE)) {
error = VFS_UNMOUNT(mp, flags);
}
if (error) {
mp->mnt_iflag &= ~IMNT_UNMOUNT;
if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0)
vfs_syncer_add_to_worklist(mp);
mp->mnt_flag |= async;
mutex_exit(mp->mnt_updating);
if (!was_suspended)
vfs_resume(mp);
if (used_extattr) {
if (start_extattr(mp) != 0)
mp->mnt_flag &= ~MNT_EXTATTR;
else
mp->mnt_flag |= MNT_EXTATTR;
}
return (error);
}
mutex_exit(mp->mnt_updating);
/*
* mark filesystem as gone to prevent further umounts
* after mnt_umounting lock is gone, this also prevents
* vfs_busy() from succeeding.
*/
mp->mnt_iflag |= IMNT_GONE;
if ((coveredvp = mp->mnt_vnodecovered) != NULLVP) {
coveredvp->v_mountedhere = NULL;
}
if (!was_suspended)
vfs_resume(mp);
mountlist_remove(mp);
if ((vp = VIMPL_TO_VNODE(TAILQ_FIRST(&mp->mnt_vnodelist))) != NULL) {
vprint("dangling", vp);
panic("unmount: dangling vnode");
}
vfs_hooks_unmount(mp);
vfs_set_lowermount(mp, NULL);
vfs_rele(mp); /* reference from mount() */
if (coveredvp != NULLVP) {
vrele(coveredvp);
}
return (0);
}
/*
* Unmount all file systems.
* We traverse the list in reverse order under the assumption that doing so
* will avoid needing to worry about dependencies.
*/
bool
vfs_unmountall(struct lwp *l)
{
printf("unmounting file systems...\n");
return vfs_unmountall1(l, true, true);
}
static void
vfs_unmount_print(struct mount *mp, const char *pfx)
{
aprint_verbose("%sunmounted %s on %s type %s\n", pfx,
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname,
mp->mnt_stat.f_fstypename);
}
/*
* Return the mount with the highest generation less than "gen".
*/
static struct mount *
vfs_unmount_next(uint64_t gen)
{
mount_iterator_t *iter;
struct mount *mp, *nmp;
nmp = NULL;
mountlist_iterator_init(&iter);
while ((mp = mountlist_iterator_next(iter)) != NULL) {
if ((nmp == NULL || mp->mnt_gen > nmp->mnt_gen) &&
mp->mnt_gen < gen) {
if (nmp != NULL)
vfs_rele(nmp);
nmp = mp;
vfs_ref(nmp);
}
}
mountlist_iterator_destroy(iter);
return nmp;
}
bool
vfs_unmount_forceone(struct lwp *l)
{
struct mount *mp;
int error;
mp = vfs_unmount_next(mountgen);
if (mp == NULL) {
return false;
}
#ifdef DEBUG
printf("forcefully unmounting %s (%s)...\n",
mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname);
#endif
if ((error = dounmount(mp, MNT_FORCE, l)) == 0) {
vfs_unmount_print(mp, "forcefully ");
return true;
} else {
vfs_rele(mp);
}
#ifdef DEBUG
printf("forceful unmount of %s failed with error %d\n",
mp->mnt_stat.f_mntonname, error);
#endif
return false;
}
bool
vfs_unmountall1(struct lwp *l, bool force, bool verbose)
{
struct mount *mp;
mount_iterator_t *iter;
bool any_error = false, progress = false;
uint64_t gen;
int error;
gen = mountgen;
for (;;) {
mp = vfs_unmount_next(gen);
if (mp == NULL)
break;
gen = mp->mnt_gen;
#ifdef DEBUG
printf("unmounting %p %s (%s)...\n",
(void *)mp, mp->mnt_stat.f_mntonname,
mp->mnt_stat.f_mntfromname);
#endif
if ((error = dounmount(mp, force ? MNT_FORCE : 0, l)) == 0) {
vfs_unmount_print(mp, "");
progress = true;
} else {
vfs_rele(mp);
if (verbose) {
printf("unmount of %s failed with error %d\n",
mp->mnt_stat.f_mntonname, error);
}
any_error = true;
}
}
if (verbose) {
printf("unmounting done\n");
}
if (any_error && verbose) {
printf("WARNING: some file systems would not unmount\n");
}
/* If the mountlist is empty it is time to remove swap. */
mountlist_iterator_init(&iter);
if (mountlist_iterator_next(iter) == NULL) {
uvm_swap_shutdown(l);
}
mountlist_iterator_destroy(iter);
return progress;
}
void
vfs_sync_all(struct lwp *l)
{
printf("syncing disks... ");
/* remove user processes from run queue */
suspendsched();
(void)spl0();
/* avoid coming back this way again if we panic. */
doing_shutdown = 1;
do_sys_sync(l);
/* Wait for sync to finish. */
if (vfs_syncwait() != 0) {
#if defined(DDB) && defined(DEBUG_HALT_BUSY)
Debugger();
#endif
printf("giving up\n");
return;
} else
printf("done\n");
}
/*
* Sync and unmount file systems before shutting down.
*/
void
vfs_shutdown(void)
{
lwp_t *l = curlwp;
vfs_sync_all(l);
/*
* If we have panicked - do not make the situation potentially
* worse by unmounting the file systems.
*/
if (panicstr != NULL) {
return;
}
/* Unmount file systems. */
vfs_unmountall(l);
}
/*
* Print a list of supported file system types (used by vfs_mountroot)
*/
static void
vfs_print_fstypes(void)
{
struct vfsops *v;
int cnt = 0;
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list)
++cnt;
mutex_exit(&vfs_list_lock);
if (cnt == 0) {
printf("WARNING: No file system modules have been loaded.\n");
return;
}
printf("Supported file systems:");
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list) {
printf(" %s", v->vfs_name);
}
mutex_exit(&vfs_list_lock);
printf("\n");
}
/*
* Mount the root file system. If the operator didn't specify a
* file system to use, try all possible file systems until one
* succeeds.
*/
int
vfs_mountroot(void)
{
struct vfsops *v;
int error = ENODEV;
if (root_device == NULL)
panic("vfs_mountroot: root device unknown");
switch (device_class(root_device)) {
case DV_IFNET:
if (rootdev != NODEV)
panic("vfs_mountroot: rootdev set for DV_IFNET "
"(0x%llx -> %llu,%llu)",
(unsigned long long)rootdev,
(unsigned long long)major(rootdev),
(unsigned long long)minor(rootdev));
break;
case DV_DISK:
if (rootdev == NODEV)
panic("vfs_mountroot: rootdev not set for DV_DISK");
if (bdevvp(rootdev, &rootvp))
panic("vfs_mountroot: can't get vnode for rootdev");
vn_lock(rootvp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_OPEN(rootvp, FREAD, FSCRED);
VOP_UNLOCK(rootvp);
if (error) {
printf("vfs_mountroot: can't open root device\n");
return (error);
}
break;
case DV_VIRTUAL:
break;
default:
printf("%s: inappropriate for root file system\n",
device_xname(root_device));
return (ENODEV);
}
/*
* If user specified a root fs type, use it. Make sure the
* specified type exists and has a mount_root()
*/
if (strcmp(rootfstype, ROOT_FSTYPE_ANY) != 0) {
v = vfs_getopsbyname(rootfstype);
error = EFTYPE;
if (v != NULL) {
if (v->vfs_mountroot != NULL) {
error = (v->vfs_mountroot)();
}
v->vfs_refcount--;
}
goto done;
}
/*
* Try each file system currently configured into the kernel.
*/
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list) {
if (v->vfs_mountroot == NULL)
continue;
#ifdef DEBUG
aprint_normal("mountroot: trying %s...\n", v->vfs_name);
#endif
v->vfs_refcount++;
mutex_exit(&vfs_list_lock);
error = (*v->vfs_mountroot)();
mutex_enter(&vfs_list_lock);
v->vfs_refcount--;
if (!error) {
aprint_normal("root file system type: %s\n",
v->vfs_name);
break;
}
}
mutex_exit(&vfs_list_lock);
if (v == NULL) {
vfs_print_fstypes();
printf("no file system for %s", device_xname(root_device));
if (device_class(root_device) == DV_DISK)
printf(" (dev 0x%llx)", (unsigned long long)rootdev);
printf("\n");
error = EFTYPE;
}
done:
if (error && device_class(root_device) == DV_DISK) {
vn_lock(rootvp, LK_EXCLUSIVE | LK_RETRY);
VOP_CLOSE(rootvp, FREAD, FSCRED);
VOP_UNLOCK(rootvp);
vrele(rootvp);
}
if (error == 0) {
mount_iterator_t *iter;
struct mount *mp;
mountlist_iterator_init(&iter);
mp = mountlist_iterator_next(iter);
KASSERT(mp != NULL);
mountlist_iterator_destroy(iter);
mp->mnt_flag |= MNT_ROOTFS;
mp->mnt_op->vfs_refcount++;
/*
* Get the vnode for '/'. Set cwdi0.cwdi_cdir to
* reference it, and donate it the reference grabbed
* with VFS_ROOT().
*/
error = VFS_ROOT(mp, LK_NONE, &rootvnode);
if (error)
panic("cannot find root vnode, error=%d", error);
cwdi0.cwdi_cdir = rootvnode;
cwdi0.cwdi_rdir = NULL;
/*
* Now that root is mounted, we can fixup initproc's CWD
* info. All other processes are kthreads, which merely
* share proc0's CWD info.
*/
initproc->p_cwdi->cwdi_cdir = rootvnode;
vref(initproc->p_cwdi->cwdi_cdir);
initproc->p_cwdi->cwdi_rdir = NULL;
/*
* Enable loading of modules from the filesystem
*/
module_load_vfs_init();
}
return (error);
}
/*
* mount_specific_key_create --
* Create a key for subsystem mount-specific data.
*/
int
mount_specific_key_create(specificdata_key_t *keyp, specificdata_dtor_t dtor)
{
return specificdata_key_create(mount_specificdata_domain, keyp, dtor);
}
/*
* mount_specific_key_delete --
* Delete a key for subsystem mount-specific data.
*/
void
mount_specific_key_delete(specificdata_key_t key)
{
specificdata_key_delete(mount_specificdata_domain, key);
}
/*
* mount_initspecific --
* Initialize a mount's specificdata container.
*/
void
mount_initspecific(struct mount *mp)
{
int error __diagused;
error = specificdata_init(mount_specificdata_domain,
&mp->mnt_specdataref);
KASSERT(error == 0);
}
/*
* mount_finispecific --
* Finalize a mount's specificdata container.
*/
void
mount_finispecific(struct mount *mp)
{
specificdata_fini(mount_specificdata_domain, &mp->mnt_specdataref);
}
/*
* mount_getspecific --
* Return mount-specific data corresponding to the specified key.
*/
void *
mount_getspecific(struct mount *mp, specificdata_key_t key)
{
return specificdata_getspecific(mount_specificdata_domain,
&mp->mnt_specdataref, key);
}
/*
* mount_setspecific --
* Set mount-specific data corresponding to the specified key.
*/
void
mount_setspecific(struct mount *mp, specificdata_key_t key, void *data)
{
specificdata_setspecific(mount_specificdata_domain,
&mp->mnt_specdataref, key, data);
}
/*
* Check to see if a filesystem is mounted on a block device.
*/
int
vfs_mountedon(vnode_t *vp)
{
vnode_t *vq;
int error = 0;
if (vp->v_type != VBLK)
return ENOTBLK;
if (spec_node_getmountedfs(vp) != NULL)
return EBUSY;
if (spec_node_lookup_by_dev(vp->v_type, vp->v_rdev, VDEAD_NOWAIT, &vq)
== 0) {
if (spec_node_getmountedfs(vq) != NULL)
error = EBUSY;
vrele(vq);
}
return error;
}
/*
* Check if a device pointed to by vp is mounted.
*
* Returns:
* EINVAL if it's not a disk
* EBUSY if it's a disk and mounted
* 0 if it's a disk and not mounted
*/
int
rawdev_mounted(vnode_t *vp, vnode_t **bvpp)
{
vnode_t *bvp;
dev_t dev;
int d_type;
bvp = NULL;
d_type = D_OTHER;
if (iskmemvp(vp))
return EINVAL;
switch (vp->v_type) {
case VCHR: {
const struct cdevsw *cdev;
dev = vp->v_rdev;
cdev = cdevsw_lookup(dev);
if (cdev != NULL) {
dev_t blkdev;
blkdev = devsw_chr2blk(dev);
if (blkdev != NODEV) {
if (vfinddev(blkdev, VBLK, &bvp) != 0) {
d_type = (cdev->d_flag & D_TYPEMASK);
/* XXX: what if bvp disappears? */
vrele(bvp);
}
}
}
break;
}
case VBLK: {
const struct bdevsw *bdev;
dev = vp->v_rdev;
bdev = bdevsw_lookup(dev);
if (bdev != NULL)
d_type = (bdev->d_flag & D_TYPEMASK);
bvp = vp;
break;
}
default:
break;
}
if (d_type != D_DISK)
return EINVAL;
if (bvpp != NULL)
*bvpp = bvp;
/*
* XXX: This is bogus. We should be failing the request
* XXX: not only if this specific slice is mounted, but
* XXX: if it's on a disk with any other mounted slice.
*/
if (vfs_mountedon(bvp))
return EBUSY;
return 0;
}
/*
* Make a 'unique' number from a mount type name.
*/
long
makefstype(const char *type)
{
long rv;
for (rv = 0; *type; type++) {
rv <<= 2;
rv ^= *type;
}
return rv;
}
static struct mountlist_entry *
mountlist_alloc(enum mountlist_type type, struct mount *mp)
{
struct mountlist_entry *me;
me = kmem_zalloc(sizeof(*me), KM_SLEEP);
me->me_mount = mp;
me->me_type = type;
return me;
}
static void
mountlist_free(struct mountlist_entry *me)
{
kmem_free(me, sizeof(*me));
}
void
mountlist_iterator_init(mount_iterator_t **mip)
{
struct mountlist_entry *me;
me = mountlist_alloc(ME_MARKER, NULL);
mutex_enter(&mountlist_lock);
TAILQ_INSERT_HEAD(&mountlist, me, me_list);
mutex_exit(&mountlist_lock);
*mip = (mount_iterator_t *)me;
}
void
mountlist_iterator_destroy(mount_iterator_t *mi)
{
struct mountlist_entry *marker = &mi->mi_entry;
if (marker->me_mount != NULL)
vfs_unbusy(marker->me_mount);
mutex_enter(&mountlist_lock);
TAILQ_REMOVE(&mountlist, marker, me_list);
mutex_exit(&mountlist_lock);
mountlist_free(marker);
}
/*
* Return the next mount or NULL for this iterator.
* Mark it busy on success.
*/
static inline struct mount *
_mountlist_iterator_next(mount_iterator_t *mi, bool wait)
{
struct mountlist_entry *me, *marker = &mi->mi_entry;
struct mount *mp;
int error;
if (marker->me_mount != NULL) {
vfs_unbusy(marker->me_mount);
marker->me_mount = NULL;
}
mutex_enter(&mountlist_lock);
for (;;) {
KASSERT(marker->me_type == ME_MARKER);
me = TAILQ_NEXT(marker, me_list);
if (me == NULL) {
/* End of list: keep marker and return. */
mutex_exit(&mountlist_lock);
return NULL;
}
TAILQ_REMOVE(&mountlist, marker, me_list);
TAILQ_INSERT_AFTER(&mountlist, me, marker, me_list);
/* Skip other markers. */
if (me->me_type != ME_MOUNT)
continue;
/* Take an initial reference for vfs_busy() below. */
mp = me->me_mount;
KASSERT(mp != NULL);
vfs_ref(mp);
mutex_exit(&mountlist_lock);
/* Try to mark this mount busy and return on success. */
if (wait)
error = vfs_busy(mp);
else
error = vfs_trybusy(mp);
if (error == 0) {
vfs_rele(mp);
marker->me_mount = mp;
return mp;
}
vfs_rele(mp);
mutex_enter(&mountlist_lock);
}
}
struct mount *
mountlist_iterator_next(mount_iterator_t *mi)
{
return _mountlist_iterator_next(mi, true);
}
struct mount *
mountlist_iterator_trynext(mount_iterator_t *mi)
{
return _mountlist_iterator_next(mi, false);
}
/*
* Attach new mount to the end of the mount list.
*/
void
mountlist_append(struct mount *mp)
{
struct mountlist_entry *me;
me = mountlist_alloc(ME_MOUNT, mp);
mutex_enter(&mountlist_lock);
TAILQ_INSERT_TAIL(&mountlist, me, me_list);
mutex_exit(&mountlist_lock);
}
/*
* Remove mount from mount list.
*/void
mountlist_remove(struct mount *mp)
{
struct mountlist_entry *me;
mutex_enter(&mountlist_lock);
TAILQ_FOREACH(me, &mountlist, me_list)
if (me->me_type == ME_MOUNT && me->me_mount == mp)
break;
KASSERT(me != NULL);
TAILQ_REMOVE(&mountlist, me, me_list);
mutex_exit(&mountlist_lock);
mountlist_free(me);
}
/*
* Unlocked variant to traverse the mountlist.
* To be used from DDB only.
*/
struct mount *
_mountlist_next(struct mount *mp)
{
struct mountlist_entry *me;
if (mp == NULL) {
me = TAILQ_FIRST(&mountlist);
} else {
TAILQ_FOREACH(me, &mountlist, me_list)
if (me->me_type == ME_MOUNT && me->me_mount == mp)
break;
if (me != NULL)
me = TAILQ_NEXT(me, me_list);
}
while (me != NULL && me->me_type != ME_MOUNT)
me = TAILQ_NEXT(me, me_list);
return (me ? me->me_mount : NULL);
}
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