/* $NetBSD: vfs_mount.c,v 1.101.2.2 2024/09/12 19:47:13 martin 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 __KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.101.2.2 2024/09/12 19:47:13 martin Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include 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) { #ifndef __HAVE_ATOMIC_AS_MEMBAR membar_release(); #endif if (__predict_true((int)atomic_dec_uint_nv(&mp->mnt_refcnt) > 0)) { return; } #ifndef __HAVE_ATOMIC_AS_MEMBAR membar_acquire(); #endif /* * 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) { struct vnode *coveredvp, *vp; struct vnode_impl *vip; 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 ((vip = TAILQ_FIRST(&mp->mnt_vnodelist)) != NULL) { vp = VIMPL_TO_VNODE(vip); 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); }