/* $NetBSD: vfs_mount.c,v 1.37 2015/08/19 08:40:02 hannken Exp $ */ /*- * Copyright (c) 1997-2011 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 1.37 2015/08/19 08:40:02 hannken Exp $"); #define _VFS_VNODE_PRIVATE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Root filesystem. */ vnode_t * rootvnode; /* Mounted filesystem list. */ struct mntlist mountlist; kmutex_t mountlist_lock; kmutex_t mntvnode_lock; kmutex_t vfs_list_lock; static specificdata_domain_t mount_specificdata_domain; static kmutex_t mntid_lock; static kmutex_t mountgen_lock; static uint64_t mountgen; void vfs_mount_sysinit(void) { TAILQ_INIT(&mountlist); mutex_init(&mountlist_lock, MUTEX_DEFAULT, IPL_NONE); mutex_init(&mntvnode_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); if (mp == NULL) return NULL; mp->mnt_op = vfsops; mp->mnt_refcnt = 1; TAILQ_INIT(&mp->mnt_vnodelist); mutex_init(&mp->mnt_unmounting, MUTEX_DEFAULT, IPL_NONE); mutex_init(&mp->mnt_renamelock, MUTEX_DEFAULT, IPL_NONE); mutex_init(&mp->mnt_updating, MUTEX_DEFAULT, IPL_NONE); error = vfs_busy(mp, NULL); KASSERT(error == 0); mp->mnt_vnodecovered = vp; mount_initspecific(mp); 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; 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; 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; fsid_t tfsid; int mtype; mutex_enter(&mntid_lock); mtype = makefstype(mp->mnt_op->vfs_name); mp->mnt_stat.f_fsidx.__fsid_val[0] = makedev(mtype, 0); mp->mnt_stat.f_fsidx.__fsid_val[1] = mtype; mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0]; if (xxxfs_mntid == 0) ++xxxfs_mntid; tfsid.__fsid_val[0] = makedev(mtype & 0xff, xxxfs_mntid); tfsid.__fsid_val[1] = mtype; if (!TAILQ_EMPTY(&mountlist)) { while (vfs_getvfs(&tfsid)) { tfsid.__fsid_val[0]++; xxxfs_mntid++; } } mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0]; 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) { struct mount *mp; mutex_enter(&mountlist_lock); TAILQ_FOREACH(mp, &mountlist, mnt_list) { 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]) { mutex_exit(&mountlist_lock); return (mp); } } mutex_exit(&mountlist_lock); return NULL; } /* * Drop a reference to a mount structure, freeing if the last reference. */ void vfs_destroy(struct mount *mp) { if (__predict_true((int)atomic_dec_uint_nv(&mp->mnt_refcnt) > 0)) { return; } /* * 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_destroy(&mp->mnt_unmounting); mutex_destroy(&mp->mnt_updating); mutex_destroy(&mp->mnt_renamelock); if (mp->mnt_op != NULL) { vfs_delref(mp->mnt_op); } kmem_free(mp, sizeof(*mp)); } /* * 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. */ int vfs_busy(struct mount *mp, struct mount **nextp) { KASSERT(mp->mnt_refcnt > 0); mutex_enter(&mp->mnt_unmounting); if (__predict_false((mp->mnt_iflag & IMNT_GONE) != 0)) { mutex_exit(&mp->mnt_unmounting); if (nextp != NULL) { KASSERT(mutex_owned(&mountlist_lock)); *nextp = TAILQ_NEXT(mp, mnt_list); } return ENOENT; } ++mp->mnt_busynest; KASSERT(mp->mnt_busynest != 0); mutex_exit(&mp->mnt_unmounting); if (nextp != NULL) { mutex_exit(&mountlist_lock); } atomic_inc_uint(&mp->mnt_refcnt); return 0; } /* * Unbusy a busy filesystem. * * Every successful vfs_busy() call must be undone by a vfs_unbusy() call. * * => If keepref is true, preserve reference added by vfs_busy(). * => If nextp != NULL, acquire mountlist_lock. */ void vfs_unbusy(struct mount *mp, bool keepref, struct mount **nextp) { KASSERT(mp->mnt_refcnt > 0); if (nextp != NULL) { mutex_enter(&mountlist_lock); } mutex_enter(&mp->mnt_unmounting); KASSERT(mp->mnt_busynest != 0); mp->mnt_busynest--; mutex_exit(&mp->mnt_unmounting); if (!keepref) { vfs_destroy(mp); } if (nextp != NULL) { KASSERT(mutex_owned(&mountlist_lock)); *nextp = TAILQ_NEXT(mp, mnt_list); } } struct vnode_iterator { struct vnode vi_vnode; }; void vfs_vnode_iterator_init(struct mount *mp, struct vnode_iterator **vip) { struct vnode *vp; vp = vnalloc(mp); mutex_enter(&mntvnode_lock); TAILQ_INSERT_HEAD(&mp->mnt_vnodelist, vp, v_mntvnodes); vp->v_usecount = 1; mutex_exit(&mntvnode_lock); *vip = (struct vnode_iterator *)vp; } void vfs_vnode_iterator_destroy(struct vnode_iterator *vi) { struct vnode *mvp = &vi->vi_vnode; mutex_enter(&mntvnode_lock); KASSERT(ISSET(mvp->v_iflag, VI_MARKER)); if (mvp->v_usecount != 0) { TAILQ_REMOVE(&mvp->v_mount->mnt_vnodelist, mvp, v_mntvnodes); mvp->v_usecount = 0; } mutex_exit(&mntvnode_lock); vnfree(mvp); } struct vnode * vfs_vnode_iterator_next(struct vnode_iterator *vi, bool (*f)(void *, struct vnode *), void *cl) { struct vnode *mvp = &vi->vi_vnode; struct mount *mp = mvp->v_mount; struct vnode *vp; int error; KASSERT(ISSET(mvp->v_iflag, VI_MARKER)); do { mutex_enter(&mntvnode_lock); vp = TAILQ_NEXT(mvp, v_mntvnodes); TAILQ_REMOVE(&mp->mnt_vnodelist, mvp, v_mntvnodes); mvp->v_usecount = 0; again: if (vp == NULL) { mutex_exit(&mntvnode_lock); return NULL; } mutex_enter(vp->v_interlock); if (ISSET(vp->v_iflag, VI_MARKER) || ISSET(vp->v_iflag, VI_XLOCK) || (f && !(*f)(cl, vp))) { mutex_exit(vp->v_interlock); vp = TAILQ_NEXT(vp, v_mntvnodes); goto again; } TAILQ_INSERT_AFTER(&mp->mnt_vnodelist, vp, mvp, v_mntvnodes); mvp->v_usecount = 1; mutex_exit(&mntvnode_lock); error = vget(vp, 0, true /* wait */); KASSERT(error == 0 || error == ENOENT); } while (error != 0); return vp; } /* * Move a vnode from one mount queue to another. */ void vfs_insmntque(vnode_t *vp, struct mount *mp) { struct mount *omp; KASSERT(mp == NULL || (mp->mnt_iflag & IMNT_UNMOUNT) == 0 || vp->v_tag == VT_VFS); mutex_enter(&mntvnode_lock); /* * Delete from old mount point vnode list, if on one. */ if ((omp = vp->v_mount) != NULL) TAILQ_REMOVE(&vp->v_mount->mnt_vnodelist, vp, v_mntvnodes); /* * 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) TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes); mutex_exit(&mntvnode_lock); if (omp != NULL) { /* Release reference to old mount. */ vfs_destroy(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 struct vflush_ctx { const struct vnode *skipvp; int flags; }; static bool vflush_selector(void *cl, struct vnode *vp) { struct vflush_ctx *c = cl; /* * Skip over a selected vnode. */ if (vp == c->skipvp) return false; /* * Skip over a vnodes marked VSYSTEM. */ if ((c->flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) return false; /* * If WRITECLOSE is set, only flush out regular file * vnodes open for writing. */ if ((c->flags & WRITECLOSE) && vp->v_type == VREG) { if (vp->v_writecount == 0) return false; } return true; } static vnode_t * vflushnext(struct vnode_iterator *marker, void *ctx, int *when) { if (hardclock_ticks > *when) { yield(); *when = hardclock_ticks + hz / 10; } return vfs_vnode_iterator_next(marker, vflush_selector, ctx); } int vflush(struct mount *mp, vnode_t *skipvp, int flags) { vnode_t *vp; struct vnode_iterator *marker; int error, busy = 0, when = 0; struct vflush_ctx ctx; /* First, flush out any vnode references from vrele_list. */ vrele_flush(); vfs_vnode_iterator_init(mp, &marker); ctx.skipvp = skipvp; ctx.flags = flags; while ((vp = vflushnext(marker, &ctx, &when)) != NULL) { /* * First try to recycle the vnode. */ if (vrecycle(vp)) continue; /* * If FORCECLOSE is set, forcibly close the vnode. */ if (flags & FORCECLOSE) { vgone(vp); continue; } #ifdef DEBUG if (busyprt) vprint("vflush: busy vnode", vp); #endif vrele(vp); busy++; } vfs_vnode_iterator_destroy(marker); if (busy) return (EBUSY); /* Wait for all vnodes to be reclaimed. */ for (;;) { mutex_enter(&mntvnode_lock); TAILQ_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) { if (vp == skipvp) continue; if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) continue; break; } if (vp != NULL) { mutex_enter(vp->v_interlock); mutex_exit(&mntvnode_lock); error = vget(vp, 0, true /* wait */); if (error == ENOENT) continue; else if (error == 0) vrele(vp); return EBUSY; } else { mutex_exit(&mntvnode_lock); 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 (olddp->v_usecount == 1) { return; } if (VFS_ROOT(olddp->v_mountedhere, &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; 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); mutex_enter(&mp->mnt_updating); error = VFS_MOUNT(mp, path, data, data_len); mp->mnt_flag &= ~MNT_OP_FLAGS; if (error != 0) goto err_unmounted; /* * 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; mutex_enter(&mountlist_lock); TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); mutex_exit(&mountlist_lock); 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); /* Hold an additional reference to the mount across VFS_START(). */ vfs_unbusy(mp, true, NULL); (void) VFS_STATVFS(mp, &mp->mnt_stat); error = VFS_START(mp, 0); if (error) { vrele(vp); } else if (flags & MNT_EXTATTR) { (void)start_extattr(mp); } /* Drop reference held for VFS_START(). */ vfs_destroy(mp); *vpp = NULL; return error; err_mounted: if (VFS_UNMOUNT(mp, MNT_FORCE) != 0) panic("Unmounting fresh file system failed"); err_unmounted: vp->v_mountedhere = NULL; mutex_exit(&mp->mnt_updating); vfs_unbusy(mp, false, NULL); vfs_destroy(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; int error, async, used_syncer, used_extattr; #if NVERIEXEC > 0 error = veriexec_unmountchk(mp); if (error) return (error); #endif /* NVERIEXEC > 0 */ /* * XXX Freeze syncer. Must do this before locking the * mount point. See dounmount() for details. */ mutex_enter(&syncer_mutex); /* * Abort unmount attempt when the filesystem is in use */ mutex_enter(&mp->mnt_unmounting); if (mp->mnt_busynest != 0) { mutex_exit(&mp->mnt_unmounting); mutex_exit(&syncer_mutex); return EBUSY; } /* * Abort unmount attempt when the filesystem is not mounted */ if ((mp->mnt_iflag & IMNT_GONE) != 0) { mutex_exit(&mp->mnt_unmounting); mutex_exit(&syncer_mutex); return ENOENT; } used_syncer = (mp->mnt_iflag & IMNT_ONWORKLIST) != 0; used_extattr = mp->mnt_flag & MNT_EXTATTR; /* * XXX Syncer must be frozen when we get here. This should really * be done on a per-mountpoint basis, but the syncer doesn't work * like that. * * The caller of dounmount() must acquire syncer_mutex because * the syncer itself acquires locks in syncer_mutex -> vfs_busy * order, and we must preserve that order to avoid deadlock. * * So, if the file system did not use the syncer, now is * the time to release the syncer_mutex. */ if (used_syncer == 0) { mutex_exit(&syncer_mutex); } 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; mutex_exit(&mp->mnt_unmounting); 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 (used_syncer) mutex_exit(&syncer_mutex); 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); /* * release mnt_umounting lock here, because other code calls * vfs_busy() while holding the mountlist_lock. * * 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; mutex_exit(&mp->mnt_unmounting); if ((coveredvp = mp->mnt_vnodecovered) != NULLVP) { vn_lock(coveredvp, LK_EXCLUSIVE | LK_RETRY); coveredvp->v_mountedhere = NULL; VOP_UNLOCK(coveredvp); } mutex_enter(&mountlist_lock); TAILQ_REMOVE(&mountlist, mp, mnt_list); mutex_exit(&mountlist_lock); if (TAILQ_FIRST(&mp->mnt_vnodelist) != NULL) panic("unmount: dangling vnode"); if (used_syncer) mutex_exit(&syncer_mutex); vfs_hooks_unmount(mp); vfs_destroy(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); } bool vfs_unmount_forceone(struct lwp *l) { struct mount *mp, *nmp; int error; nmp = NULL; TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) { if (nmp == NULL || mp->mnt_gen > nmp->mnt_gen) { nmp = mp; } } if (nmp == NULL) { return false; } #ifdef DEBUG printf("forcefully unmounting %s (%s)...\n", nmp->mnt_stat.f_mntonname, nmp->mnt_stat.f_mntfromname); #endif atomic_inc_uint(&nmp->mnt_refcnt); if ((error = dounmount(nmp, MNT_FORCE, l)) == 0) { vfs_unmount_print(nmp, "forcefully "); return true; } else { vfs_destroy(nmp); } #ifdef DEBUG printf("forceful unmount of %s failed with error %d\n", nmp->mnt_stat.f_mntonname, error); #endif return false; } bool vfs_unmountall1(struct lwp *l, bool force, bool verbose) { struct mount *mp, *nmp; bool any_error = false, progress = false; int error; TAILQ_FOREACH_REVERSE_SAFE(mp, &mountlist, mntlist, mnt_list, nmp) { #ifdef DEBUG printf("unmounting %p %s (%s)...\n", (void *)mp, mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname); #endif atomic_inc_uint(&mp->mnt_refcnt); if ((error = dounmount(mp, force ? MNT_FORCE : 0, l)) == 0) { vfs_unmount_print(mp, ""); progress = true; } else { vfs_destroy(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"); } 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 (buf_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 paniced - 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"); error = VOP_OPEN(rootvp, FREAD, FSCRED); 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) { VOP_CLOSE(rootvp, FREAD, FSCRED); vrele(rootvp); } if (error == 0) { struct mount *mp; extern struct cwdinfo cwdi0; mp = TAILQ_FIRST(&mountlist); mp->mnt_flag |= MNT_ROOTFS; mp->mnt_op->vfs_refcount++; /* * Get the vnode for '/'. Set cwdi0.cwdi_cdir to * reference it. */ error = VFS_ROOT(mp, &rootvnode); if (error) panic("cannot find root vnode, error=%d", error); cwdi0.cwdi_cdir = rootvnode; vref(cwdi0.cwdi_cdir); VOP_UNLOCK(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, &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; } void mountlist_append(struct mount *mp) { mutex_enter(&mountlist_lock); TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list); mutex_exit(&mountlist_lock); }