/* $NetBSD: vfs_subr.c,v 1.350 2008/06/05 12:32:57 ad Exp $ */ /*- * Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008 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 */ /* * External virtual filesystem routines. * * This file contains vfs subroutines which are heavily dependant on * the kernel and are not suitable for standalone use. Examples include * routines involved vnode and mountpoint management. * * Note on v_usecount and locking: * * At nearly all points it is known that v_usecount could be zero, the * vnode interlock will be held. * * To change v_usecount away from zero, the interlock must be held. To * change from a non-zero value to zero, again the interlock must be * held. * * Changing the usecount from a non-zero value to a non-zero value can * safely be done using atomic operations, without the interlock held. */ #include __KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.350 2008/06/05 12:32:57 ad Exp $"); #include "opt_ddb.h" #include "opt_compat_netbsd.h" #include "opt_compat_43.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern int dovfsusermount; /* 1 => permit any user to mount filesystems */ extern int vfs_magiclinks; /* 1 => expand "magic" symlinks */ static vnodelst_t vnode_free_list = TAILQ_HEAD_INITIALIZER(vnode_free_list); static vnodelst_t vnode_hold_list = TAILQ_HEAD_INITIALIZER(vnode_hold_list); static vnodelst_t vrele_list = TAILQ_HEAD_INITIALIZER(vrele_list); static int vrele_pending; static kmutex_t vrele_lock; static kcondvar_t vrele_cv; static lwp_t *vrele_lwp; static pool_cache_t vnode_cache; MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes"); /* * Local declarations. */ static void vrele_thread(void *); static void insmntque(vnode_t *, struct mount *); static int getdevvp(dev_t, vnode_t **, enum vtype); static vnode_t *getcleanvnode(void);; void vpanic(vnode_t *, const char *); #ifdef DIAGNOSTIC void vpanic(vnode_t *vp, const char *msg) { vprint(NULL, vp); panic("%s\n", msg); } #else #define vpanic(vp, msg) /* nothing */ #endif void vn_init1(void) { vnode_cache = pool_cache_init(sizeof(struct vnode), 0, 0, 0, "vnodepl", NULL, IPL_NONE, NULL, NULL, NULL); KASSERT(vnode_cache != NULL); /* Create deferred release thread. */ mutex_init(&vrele_lock, MUTEX_DEFAULT, IPL_NONE); cv_init(&vrele_cv, "vrele"); if (kthread_create(PRI_VM, KTHREAD_MPSAFE, NULL, vrele_thread, NULL, &vrele_lwp, "vrele")) panic("fork vrele"); } int vfs_drainvnodes(long target, struct lwp *l) { while (numvnodes > target) { vnode_t *vp; mutex_enter(&vnode_free_list_lock); vp = getcleanvnode(); if (vp == NULL) return EBUSY; /* give up */ ungetnewvnode(vp); } return 0; } /* * grab a vnode from freelist and clean it. */ vnode_t * getcleanvnode(void) { vnode_t *vp; vnodelst_t *listhd; KASSERT(mutex_owned(&vnode_free_list_lock)); retry: listhd = &vnode_free_list; try_nextlist: TAILQ_FOREACH(vp, listhd, v_freelist) { /* * It's safe to test v_usecount and v_iflag * without holding the interlock here, since * these vnodes should never appear on the * lists. */ if (vp->v_usecount != 0) { vpanic(vp, "free vnode isn't"); } if ((vp->v_iflag & VI_CLEAN) != 0) { vpanic(vp, "clean vnode on freelist"); } if (vp->v_freelisthd != listhd) { printf("vnode sez %p, listhd %p\n", vp->v_freelisthd, listhd); vpanic(vp, "list head mismatch"); } if (!mutex_tryenter(&vp->v_interlock)) continue; /* * Our lwp might hold the underlying vnode * locked, so don't try to reclaim a VI_LAYER * node if it's locked. */ if ((vp->v_iflag & VI_XLOCK) == 0 && ((vp->v_iflag & VI_LAYER) == 0 || VOP_ISLOCKED(vp) == 0)) { break; } mutex_exit(&vp->v_interlock); } if (vp == NULL) { if (listhd == &vnode_free_list) { listhd = &vnode_hold_list; goto try_nextlist; } mutex_exit(&vnode_free_list_lock); return NULL; } /* Remove it from the freelist. */ TAILQ_REMOVE(listhd, vp, v_freelist); vp->v_freelisthd = NULL; mutex_exit(&vnode_free_list_lock); /* * The vnode is still associated with a file system, so we must * clean it out before reusing it. We need to add a reference * before doing this. If the vnode gains another reference while * being cleaned out then we lose - retry. */ atomic_inc_uint(&vp->v_usecount); vclean(vp, DOCLOSE); if (vp->v_usecount == 1) { /* We're about to dirty it. */ vp->v_iflag &= ~VI_CLEAN; mutex_exit(&vp->v_interlock); if (vp->v_type == VBLK || vp->v_type == VCHR) { spec_node_destroy(vp); } vp->v_type = VNON; } else { /* * Don't return to freelist - the holder of the last * reference will destroy it. */ vrelel(vp, 0); /* releases vp->v_interlock */ mutex_enter(&vnode_free_list_lock); goto retry; } if (vp->v_data != NULL || vp->v_uobj.uo_npages != 0 || !TAILQ_EMPTY(&vp->v_uobj.memq)) { vpanic(vp, "cleaned vnode isn't"); } if (vp->v_numoutput != 0) { vpanic(vp, "clean vnode has pending I/O's"); } if ((vp->v_iflag & VI_ONWORKLST) != 0) { vpanic(vp, "clean vnode on syncer list"); } return vp; } /* * 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. * * => 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); if (__predict_false(!rw_tryenter(&mp->mnt_unmounting, RW_READER))) { if (nextp != NULL) { KASSERT(mutex_owned(&mountlist_lock)); *nextp = CIRCLEQ_NEXT(mp, mnt_list); } return EBUSY; } if (__predict_false((mp->mnt_iflag & IMNT_GONE) != 0)) { rw_exit(&mp->mnt_unmounting); if (nextp != NULL) { KASSERT(mutex_owned(&mountlist_lock)); *nextp = CIRCLEQ_NEXT(mp, mnt_list); } return ENOENT; } if (nextp != NULL) { mutex_exit(&mountlist_lock); } atomic_inc_uint(&mp->mnt_refcnt); return 0; } /* * Unbusy a busy filesystem. * * => 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); } rw_exit(&mp->mnt_unmounting); if (!keepref) { vfs_destroy(mp); } if (nextp != NULL) { KASSERT(mutex_owned(&mountlist_lock)); *nextp = CIRCLEQ_NEXT(mp, mnt_list); } } /* * 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); mp = kmem_zalloc(sizeof(*mp), KM_SLEEP); if (mp == NULL) return ENOMEM; mp->mnt_refcnt = 1; rw_init(&mp->mnt_unmounting); mutex_init(&mp->mnt_updating, MUTEX_DEFAULT, IPL_NONE); mutex_init(&mp->mnt_renamelock, MUTEX_DEFAULT, IPL_NONE); (void)vfs_busy(mp, NULL); TAILQ_INIT(&mp->mnt_vnodelist); mp->mnt_op = vfsp; mp->mnt_flag = MNT_RDONLY; mp->mnt_vnodecovered = NULL; (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); mount_initspecific(mp); *mpp = mp; return (0); } /* * Routines having to do with the management of the vnode table. */ extern int (**dead_vnodeop_p)(void *); /* * Return the next vnode from the free list. */ int getnewvnode(enum vtagtype tag, struct mount *mp, int (**vops)(void *), vnode_t **vpp) { struct uvm_object *uobj; static int toggle; vnode_t *vp; int error = 0, tryalloc; try_again: if (mp != NULL) { /* * Mark filesystem busy while we're creating a * vnode. If unmount is in progress, this will * fail. */ error = vfs_busy(mp, NULL); if (error) return error; } /* * We must choose whether to allocate a new vnode or recycle an * existing one. The criterion for allocating a new one is that * the total number of vnodes is less than the number desired or * there are no vnodes on either free list. Generally we only * want to recycle vnodes that have no buffers associated with * them, so we look first on the vnode_free_list. If it is empty, * we next consider vnodes with referencing buffers on the * vnode_hold_list. The toggle ensures that half the time we * will use a buffer from the vnode_hold_list, and half the time * we will allocate a new one unless the list has grown to twice * the desired size. We are reticent to recycle vnodes from the * vnode_hold_list because we will lose the identity of all its * referencing buffers. */ vp = NULL; mutex_enter(&vnode_free_list_lock); toggle ^= 1; if (numvnodes > 2 * desiredvnodes) toggle = 0; tryalloc = numvnodes < desiredvnodes || (TAILQ_FIRST(&vnode_free_list) == NULL && (TAILQ_FIRST(&vnode_hold_list) == NULL || toggle)); if (tryalloc) { numvnodes++; mutex_exit(&vnode_free_list_lock); if ((vp = vnalloc(NULL)) == NULL) { mutex_enter(&vnode_free_list_lock); numvnodes--; } else vp->v_usecount = 1; } if (vp == NULL) { vp = getcleanvnode(); if (vp == NULL) { if (mp != NULL) { vfs_unbusy(mp, false, NULL); } if (tryalloc) { printf("WARNING: unable to allocate new " "vnode, retrying...\n"); kpause("newvn", false, hz, NULL); goto try_again; } tablefull("vnode", "increase kern.maxvnodes or NVNODE"); *vpp = 0; return (ENFILE); } vp->v_iflag = 0; vp->v_vflag = 0; vp->v_uflag = 0; vp->v_socket = NULL; } KASSERT(vp->v_usecount == 1); KASSERT(vp->v_freelisthd == NULL); KASSERT(LIST_EMPTY(&vp->v_nclist)); KASSERT(LIST_EMPTY(&vp->v_dnclist)); vp->v_type = VNON; vp->v_vnlock = &vp->v_lock; vp->v_tag = tag; vp->v_op = vops; insmntque(vp, mp); *vpp = vp; vp->v_data = 0; /* * initialize uvm_object within vnode. */ uobj = &vp->v_uobj; KASSERT(uobj->pgops == &uvm_vnodeops); KASSERT(uobj->uo_npages == 0); KASSERT(TAILQ_FIRST(&uobj->memq) == NULL); vp->v_size = vp->v_writesize = VSIZENOTSET; if (mp != NULL) { if ((mp->mnt_iflag & IMNT_MPSAFE) != 0) vp->v_vflag |= VV_MPSAFE; vfs_unbusy(mp, true, NULL); } return (0); } /* * This is really just the reverse of getnewvnode(). Needed for * VFS_VGET functions who may need to push back a vnode in case * of a locking race. */ void ungetnewvnode(vnode_t *vp) { KASSERT(vp->v_usecount == 1); KASSERT(vp->v_data == NULL); KASSERT(vp->v_freelisthd == NULL); mutex_enter(&vp->v_interlock); vp->v_iflag |= VI_CLEAN; vrelel(vp, 0); } /* * Allocate a new, uninitialized vnode. If 'mp' is non-NULL, this is a * marker vnode and we are prepared to wait for the allocation. */ vnode_t * vnalloc(struct mount *mp) { vnode_t *vp; vp = pool_cache_get(vnode_cache, (mp != NULL ? PR_WAITOK : PR_NOWAIT)); if (vp == NULL) { return NULL; } memset(vp, 0, sizeof(*vp)); UVM_OBJ_INIT(&vp->v_uobj, &uvm_vnodeops, 0); cv_init(&vp->v_cv, "vnode"); /* * done by memset() above. * LIST_INIT(&vp->v_nclist); * LIST_INIT(&vp->v_dnclist); */ if (mp != NULL) { vp->v_mount = mp; vp->v_type = VBAD; vp->v_iflag = VI_MARKER; } else { rw_init(&vp->v_lock.vl_lock); } return vp; } /* * Free an unused, unreferenced vnode. */ void vnfree(vnode_t *vp) { KASSERT(vp->v_usecount == 0); if ((vp->v_iflag & VI_MARKER) == 0) { rw_destroy(&vp->v_lock.vl_lock); mutex_enter(&vnode_free_list_lock); numvnodes--; mutex_exit(&vnode_free_list_lock); } UVM_OBJ_DESTROY(&vp->v_uobj); cv_destroy(&vp->v_cv); pool_cache_put(vnode_cache, vp); } /* * Remove a vnode from its freelist. */ static inline void vremfree(vnode_t *vp) { KASSERT(mutex_owned(&vp->v_interlock)); KASSERT(vp->v_usecount == 0); /* * Note that the reference count must not change until * the vnode is removed. */ mutex_enter(&vnode_free_list_lock); if (vp->v_holdcnt > 0) { KASSERT(vp->v_freelisthd == &vnode_hold_list); } else { KASSERT(vp->v_freelisthd == &vnode_free_list); } TAILQ_REMOVE(vp->v_freelisthd, vp, v_freelist); vp->v_freelisthd = NULL; mutex_exit(&vnode_free_list_lock); } /* * Move a vnode from one mount queue to another. */ static void insmntque(vnode_t *vp, struct mount *mp) { struct mount *omp; #ifdef DIAGNOSTIC if ((mp != NULL) && (mp->mnt_iflag & IMNT_UNMOUNT) && !(mp->mnt_flag & MNT_SOFTDEP) && vp->v_tag != VT_VFS) { panic("insmntque into dying filesystem"); } #endif 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); } } /* * Create a vnode for a block device. * Used for root filesystem and swap areas. * Also used for memory file system special devices. */ int bdevvp(dev_t dev, vnode_t **vpp) { return (getdevvp(dev, vpp, VBLK)); } /* * Create a vnode for a character device. * Used for kernfs and some console handling. */ int cdevvp(dev_t dev, vnode_t **vpp) { return (getdevvp(dev, vpp, VCHR)); } /* * Create a vnode for a device. * Used by bdevvp (block device) for root file system etc., * and by cdevvp (character device) for console and kernfs. */ static int getdevvp(dev_t dev, vnode_t **vpp, enum vtype type) { vnode_t *vp; vnode_t *nvp; int error; if (dev == NODEV) { *vpp = NULL; return (0); } error = getnewvnode(VT_NON, NULL, spec_vnodeop_p, &nvp); if (error) { *vpp = NULL; return (error); } vp = nvp; vp->v_type = type; vp->v_vflag |= VV_MPSAFE; uvm_vnp_setsize(vp, 0); spec_node_init(vp, dev); *vpp = vp; return (0); } /* * Try to gain a reference to a vnode, without acquiring its interlock. * The caller must hold a lock that will prevent the vnode from being * recycled or freed. */ bool vtryget(vnode_t *vp) { u_int use, next; /* * If the vnode is being freed, don't make life any harder * for vclean() by adding another reference without waiting. * This is not strictly necessary, but we'll do it anyway. */ if (__predict_false((vp->v_iflag & (VI_XLOCK | VI_FREEING)) != 0)) { return false; } for (use = vp->v_usecount;; use = next) { if (use == 0) { /* Need interlock held if first reference. */ return false; } next = atomic_cas_uint(&vp->v_usecount, use, use + 1); if (__predict_true(next == use)) { return true; } } } /* * Grab a particular vnode from the free list, increment its * reference count and lock it. If the vnode lock bit is set the * vnode is being eliminated in vgone. In that case, we can not * grab the vnode, so the process is awakened when the transition is * completed, and an error returned to indicate that the vnode is no * longer usable (possibly having been changed to a new file system type). */ int vget(vnode_t *vp, int flags) { int error; KASSERT((vp->v_iflag & VI_MARKER) == 0); if ((flags & LK_INTERLOCK) == 0) mutex_enter(&vp->v_interlock); /* * Before adding a reference, we must remove the vnode * from its freelist. */ if (vp->v_usecount == 0) { vremfree(vp); vp->v_usecount = 1; } else { atomic_inc_uint(&vp->v_usecount); } /* * If the vnode is in the process of being cleaned out for * another use, we wait for the cleaning to finish and then * return failure. Cleaning is determined by checking if * the VI_XLOCK or VI_FREEING flags are set. */ if ((vp->v_iflag & (VI_XLOCK | VI_FREEING)) != 0) { if ((flags & LK_NOWAIT) != 0) { vrelel(vp, 0); return EBUSY; } vwait(vp, VI_XLOCK | VI_FREEING); vrelel(vp, 0); return ENOENT; } if (flags & LK_TYPE_MASK) { error = vn_lock(vp, flags | LK_INTERLOCK); if (error != 0) { vrele(vp); } return error; } mutex_exit(&vp->v_interlock); return 0; } /* * vput(), just unlock and vrele() */ void vput(vnode_t *vp) { KASSERT((vp->v_iflag & VI_MARKER) == 0); VOP_UNLOCK(vp, 0); vrele(vp); } /* * Try to drop reference on a vnode. Abort if we are releasing the * last reference. */ static inline bool vtryrele(vnode_t *vp) { u_int use, next; for (use = vp->v_usecount;; use = next) { if (use == 1) { return false; } next = atomic_cas_uint(&vp->v_usecount, use, use - 1); if (__predict_true(next == use)) { return true; } } } /* * Vnode release. If reference count drops to zero, call inactive * routine and either return to freelist or free to the pool. */ void vrelel(vnode_t *vp, int flags) { bool recycle, defer; int error; KASSERT(mutex_owned(&vp->v_interlock)); KASSERT((vp->v_iflag & VI_MARKER) == 0); KASSERT(vp->v_freelisthd == NULL); if (vp->v_op == dead_vnodeop_p && (vp->v_iflag & VI_CLEAN) == 0) { vpanic(vp, "dead but not clean"); } /* * If not the last reference, just drop the reference count * and unlock. */ if (vtryrele(vp)) { vp->v_iflag |= VI_INACTREDO; mutex_exit(&vp->v_interlock); return; } if (vp->v_usecount <= 0 || vp->v_writecount != 0) { vpanic(vp, "vput: bad ref count"); } /* * If not clean, deactivate the vnode, but preserve * our reference across the call to VOP_INACTIVE(). */ retry: if ((vp->v_iflag & VI_CLEAN) == 0) { recycle = false; vp->v_iflag |= VI_INACTNOW; /* * XXX This ugly block can be largely eliminated if * locking is pushed down into the file systems. */ if (curlwp == uvm.pagedaemon_lwp) { /* The pagedaemon can't wait around; defer. */ defer = true; } else if (curlwp == vrele_lwp) { /* We have to try harder. */ vp->v_iflag &= ~VI_INACTREDO; error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY); if (error != 0) { /* XXX */ vpanic(vp, "vrele: unable to lock %p"); } defer = false; } else if ((vp->v_iflag & VI_LAYER) != 0) { /* * Acquiring the stack's lock in vclean() even * for an honest vput/vrele is dangerous because * our caller may hold other vnode locks; defer. */ defer = true; } else { /* If we can't acquire the lock, then defer. */ vp->v_iflag &= ~VI_INACTREDO; error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_NOWAIT); if (error != 0) { defer = true; mutex_enter(&vp->v_interlock); } else { defer = false; } } if (defer) { /* * Defer reclaim to the kthread; it's not safe to * clean it here. We donate it our last reference. */ KASSERT(mutex_owned(&vp->v_interlock)); KASSERT((vp->v_iflag & VI_INACTPEND) == 0); vp->v_iflag &= ~VI_INACTNOW; vp->v_iflag |= VI_INACTPEND; mutex_enter(&vrele_lock); TAILQ_INSERT_TAIL(&vrele_list, vp, v_freelist); if (++vrele_pending > (desiredvnodes >> 8)) cv_signal(&vrele_cv); mutex_exit(&vrele_lock); mutex_exit(&vp->v_interlock); return; } #ifdef DIAGNOSTIC if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_specnode != NULL && vp->v_specnode->sn_opencnt != 0) { vprint("vrelel: missing VOP_CLOSE()", vp); } #endif /* * The vnode can gain another reference while being * deactivated. If VOP_INACTIVE() indicates that * the described file has been deleted, then recycle * the vnode irrespective of additional references. * Another thread may be waiting to re-use the on-disk * inode. * * Note that VOP_INACTIVE() will drop the vnode lock. */ VOP_INACTIVE(vp, &recycle); mutex_enter(&vp->v_interlock); vp->v_iflag &= ~VI_INACTNOW; if (!recycle) { if (vtryrele(vp)) { mutex_exit(&vp->v_interlock); return; } /* * If we grew another reference while * VOP_INACTIVE() was underway, retry. */ if ((vp->v_iflag & VI_INACTREDO) != 0) { goto retry; } } /* Take care of space accounting. */ if (vp->v_iflag & VI_EXECMAP) { atomic_add_int(&uvmexp.execpages, -vp->v_uobj.uo_npages); atomic_add_int(&uvmexp.filepages, vp->v_uobj.uo_npages); } vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP); vp->v_vflag &= ~VV_MAPPED; /* * Recycle the vnode if the file is now unused (unlinked), * otherwise just free it. */ if (recycle) { vclean(vp, DOCLOSE); } KASSERT(vp->v_usecount > 0); } if (atomic_dec_uint_nv(&vp->v_usecount) != 0) { /* Gained another reference while being reclaimed. */ mutex_exit(&vp->v_interlock); return; } if ((vp->v_iflag & VI_CLEAN) != 0) { /* * It's clean so destroy it. It isn't referenced * anywhere since it has been reclaimed. */ KASSERT(vp->v_holdcnt == 0); KASSERT(vp->v_writecount == 0); mutex_exit(&vp->v_interlock); insmntque(vp, NULL); if (vp->v_type == VBLK || vp->v_type == VCHR) { spec_node_destroy(vp); } vnfree(vp); } else { /* * Otherwise, put it back onto the freelist. It * can't be destroyed while still associated with * a file system. */ mutex_enter(&vnode_free_list_lock); if (vp->v_holdcnt > 0) { vp->v_freelisthd = &vnode_hold_list; } else { vp->v_freelisthd = &vnode_free_list; } TAILQ_INSERT_TAIL(vp->v_freelisthd, vp, v_freelist); mutex_exit(&vnode_free_list_lock); mutex_exit(&vp->v_interlock); } } void vrele(vnode_t *vp) { KASSERT((vp->v_iflag & VI_MARKER) == 0); if ((vp->v_iflag & VI_INACTNOW) == 0 && vtryrele(vp)) { return; } mutex_enter(&vp->v_interlock); vrelel(vp, 0); } static void vrele_thread(void *cookie) { vnode_t *vp; for (;;) { mutex_enter(&vrele_lock); while (TAILQ_EMPTY(&vrele_list)) { cv_timedwait(&vrele_cv, &vrele_lock, hz); } vp = TAILQ_FIRST(&vrele_list); TAILQ_REMOVE(&vrele_list, vp, v_freelist); vrele_pending--; mutex_exit(&vrele_lock); /* * If not the last reference, then ignore the vnode * and look for more work. */ mutex_enter(&vp->v_interlock); KASSERT((vp->v_iflag & VI_INACTPEND) != 0); vp->v_iflag &= ~VI_INACTPEND; vrelel(vp, 0); } } /* * Page or buffer structure gets a reference. * Called with v_interlock held. */ void vholdl(vnode_t *vp) { KASSERT(mutex_owned(&vp->v_interlock)); KASSERT((vp->v_iflag & VI_MARKER) == 0); if (vp->v_holdcnt++ == 0 && vp->v_usecount == 0) { mutex_enter(&vnode_free_list_lock); KASSERT(vp->v_freelisthd == &vnode_free_list); TAILQ_REMOVE(vp->v_freelisthd, vp, v_freelist); vp->v_freelisthd = &vnode_hold_list; TAILQ_INSERT_TAIL(vp->v_freelisthd, vp, v_freelist); mutex_exit(&vnode_free_list_lock); } } /* * Page or buffer structure frees a reference. * Called with v_interlock held. */ void holdrelel(vnode_t *vp) { KASSERT(mutex_owned(&vp->v_interlock)); KASSERT((vp->v_iflag & VI_MARKER) == 0); if (vp->v_holdcnt <= 0) { vpanic(vp, "holdrelel: holdcnt vp %p"); } vp->v_holdcnt--; if (vp->v_holdcnt == 0 && vp->v_usecount == 0) { mutex_enter(&vnode_free_list_lock); KASSERT(vp->v_freelisthd == &vnode_hold_list); TAILQ_REMOVE(vp->v_freelisthd, vp, v_freelist); vp->v_freelisthd = &vnode_free_list; TAILQ_INSERT_TAIL(vp->v_freelisthd, vp, v_freelist); mutex_exit(&vnode_free_list_lock); } } /* * Vnode reference, where a reference is already held by some other * object (for example, a file structure). */ void vref(vnode_t *vp) { KASSERT((vp->v_iflag & VI_MARKER) == 0); KASSERT(vp->v_usecount != 0); atomic_inc_uint(&vp->v_usecount); } /* * 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 V_SYSTEM to be skipped. */ #ifdef DEBUG int busyprt = 0; /* print out busy vnodes */ struct ctldebug debug1 = { "busyprt", &busyprt }; #endif static vnode_t * vflushnext(vnode_t *mvp, int *when) { if (hardclock_ticks > *when) { mutex_exit(&mntvnode_lock); yield(); mutex_enter(&mntvnode_lock); *when = hardclock_ticks + hz / 10; } return vunmark(mvp); } int vflush(struct mount *mp, vnode_t *skipvp, int flags) { vnode_t *vp, *mvp; int busy = 0, when = 0; /* Allocate a marker vnode. */ if ((mvp = vnalloc(mp)) == NULL) return (ENOMEM); mutex_enter(&mntvnode_lock); /* * NOTE: not using the TAILQ_FOREACH here since in this loop vgone() * and vclean() are called */ for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp != NULL; vp = vflushnext(mvp, &when)) { vmark(mvp, vp); if (vp->v_mount != mp || vismarker(vp)) continue; /* * Skip over a selected vnode. */ if (vp == skipvp) continue; mutex_enter(&vp->v_interlock); /* * Ignore clean but still referenced vnodes. */ if ((vp->v_iflag & VI_CLEAN) != 0) { mutex_exit(&vp->v_interlock); continue; } /* * Skip over a vnodes marked VSYSTEM. */ if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) { mutex_exit(&vp->v_interlock); continue; } /* * If WRITECLOSE is set, only flush out regular file * vnodes open for writing. */ if ((flags & WRITECLOSE) && (vp->v_writecount == 0 || vp->v_type != VREG)) { mutex_exit(&vp->v_interlock); continue; } /* * With v_usecount == 0, all we need to do is clear * out the vnode data structures and we are done. */ if (vp->v_usecount == 0) { mutex_exit(&mntvnode_lock); vremfree(vp); vp->v_usecount = 1; vclean(vp, DOCLOSE); vrelel(vp, 0); mutex_enter(&mntvnode_lock); continue; } /* * 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) { mutex_exit(&mntvnode_lock); atomic_inc_uint(&vp->v_usecount); if (vp->v_type != VBLK && vp->v_type != VCHR) { vclean(vp, DOCLOSE); vrelel(vp, 0); } else { vclean(vp, 0); vp->v_op = spec_vnodeop_p; /* XXXSMP */ mutex_exit(&vp->v_interlock); /* * The vnode isn't clean, but still resides * on the mount list. Remove it. XXX This * is a bit dodgy. */ insmntque(vp, NULL); vrele(vp); } mutex_enter(&mntvnode_lock); continue; } #ifdef DEBUG if (busyprt) vprint("vflush: busy vnode", vp); #endif mutex_exit(&vp->v_interlock); busy++; } mutex_exit(&mntvnode_lock); vnfree(mvp); if (busy) return (EBUSY); return (0); } /* * Disassociate the underlying file system from a vnode. * * Must be called with the interlock held, and will return with it held. */ void vclean(vnode_t *vp, int flags) { lwp_t *l = curlwp; bool recycle, active; int error; KASSERT(mutex_owned(&vp->v_interlock)); KASSERT((vp->v_iflag & VI_MARKER) == 0); KASSERT(vp->v_usecount != 0); /* If cleaning is already in progress wait until done and return. */ if (vp->v_iflag & VI_XLOCK) { vwait(vp, VI_XLOCK); return; } /* If already clean, nothing to do. */ if ((vp->v_iflag & VI_CLEAN) != 0) { return; } /* * Prevent the vnode from being recycled or brought into use * while we clean it out. */ vp->v_iflag |= VI_XLOCK; if (vp->v_iflag & VI_EXECMAP) { atomic_add_int(&uvmexp.execpages, -vp->v_uobj.uo_npages); atomic_add_int(&uvmexp.filepages, vp->v_uobj.uo_npages); } vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP); active = (vp->v_usecount > 1); /* XXXAD should not lock vnode under layer */ VOP_LOCK(vp, LK_EXCLUSIVE | LK_INTERLOCK); /* * Clean out any cached data associated with the vnode. * If purging an active vnode, it must be closed and * deactivated before being reclaimed. Note that the * VOP_INACTIVE will unlock the vnode. */ if (flags & DOCLOSE) { error = vinvalbuf(vp, V_SAVE, NOCRED, l, 0, 0); if (error != 0) error = vinvalbuf(vp, 0, NOCRED, l, 0, 0); KASSERT(error == 0); KASSERT((vp->v_iflag & VI_ONWORKLST) == 0); if (active && (vp->v_type == VBLK || vp->v_type == VCHR)) { spec_node_revoke(vp); } } if (active) { VOP_INACTIVE(vp, &recycle); } else { /* * Any other processes trying to obtain this lock must first * wait for VI_XLOCK to clear, then call the new lock operation. */ VOP_UNLOCK(vp, 0); } /* Disassociate the underlying file system from the vnode. */ if (VOP_RECLAIM(vp)) { vpanic(vp, "vclean: cannot reclaim"); } KASSERT(vp->v_uobj.uo_npages == 0); if (vp->v_type == VREG && vp->v_ractx != NULL) { uvm_ra_freectx(vp->v_ractx); vp->v_ractx = NULL; } cache_purge(vp); /* Done with purge, notify sleepers of the grim news. */ vp->v_op = dead_vnodeop_p; vp->v_tag = VT_NON; mutex_enter(&vp->v_interlock); vp->v_vnlock = &vp->v_lock; KNOTE(&vp->v_klist, NOTE_REVOKE); vp->v_iflag &= ~(VI_XLOCK | VI_FREEING); vp->v_vflag &= ~VV_LOCKSWORK; if ((flags & DOCLOSE) != 0) { vp->v_iflag |= VI_CLEAN; } cv_broadcast(&vp->v_cv); KASSERT((vp->v_iflag & VI_ONWORKLST) == 0); } /* * Recycle an unused vnode to the front of the free list. * Release the passed interlock if the vnode will be recycled. */ int vrecycle(vnode_t *vp, kmutex_t *inter_lkp, struct lwp *l) { KASSERT((vp->v_iflag & VI_MARKER) == 0); mutex_enter(&vp->v_interlock); if (vp->v_usecount != 0) { mutex_exit(&vp->v_interlock); return (0); } if (inter_lkp) mutex_exit(inter_lkp); vremfree(vp); vp->v_usecount = 1; vclean(vp, DOCLOSE); vrelel(vp, 0); return (1); } /* * Eliminate all activity associated with a vnode in preparation for * reuse. Drops a reference from the vnode. */ void vgone(vnode_t *vp) { mutex_enter(&vp->v_interlock); vclean(vp, DOCLOSE); vrelel(vp, 0); } /* * Lookup a vnode by device number. */ int vfinddev(dev_t dev, enum vtype type, vnode_t **vpp) { vnode_t *vp; int rc = 0; mutex_enter(&specfs_lock); for (vp = specfs_hash[SPECHASH(dev)]; vp; vp = vp->v_specnext) { if (dev != vp->v_rdev || type != vp->v_type) continue; *vpp = vp; rc = 1; break; } mutex_exit(&specfs_lock); return (rc); } /* * Revoke all the vnodes corresponding to the specified minor number * range (endpoints inclusive) of the specified major. */ void vdevgone(int maj, int minl, int minh, enum vtype type) { vnode_t *vp, **vpp; dev_t dev; int mn; vp = NULL; /* XXX gcc */ mutex_enter(&specfs_lock); for (mn = minl; mn <= minh; mn++) { dev = makedev(maj, mn); vpp = &specfs_hash[SPECHASH(dev)]; for (vp = *vpp; vp != NULL;) { mutex_enter(&vp->v_interlock); if ((vp->v_iflag & VI_CLEAN) != 0 || dev != vp->v_rdev || type != vp->v_type) { mutex_exit(&vp->v_interlock); vp = vp->v_specnext; continue; } mutex_exit(&specfs_lock); if (vget(vp, LK_INTERLOCK) == 0) { VOP_REVOKE(vp, REVOKEALL); vrele(vp); } mutex_enter(&specfs_lock); vp = *vpp; } } mutex_exit(&specfs_lock); } /* * Calculate the total number of references to a special device. */ int vcount(vnode_t *vp) { int count; mutex_enter(&specfs_lock); mutex_enter(&vp->v_interlock); if (vp->v_specnode == NULL) { count = vp->v_usecount - ((vp->v_iflag & VI_INACTPEND) != 0); mutex_exit(&vp->v_interlock); mutex_exit(&specfs_lock); return (count); } mutex_exit(&vp->v_interlock); count = vp->v_specnode->sn_dev->sd_opencnt; mutex_exit(&specfs_lock); return (count); } /* * Eliminate all activity associated with the requested vnode * and with all vnodes aliased to the requested vnode. */ void vrevoke(vnode_t *vp) { vnode_t *vq, **vpp; enum vtype type; dev_t dev; KASSERT(vp->v_usecount > 0); mutex_enter(&vp->v_interlock); if ((vp->v_iflag & VI_CLEAN) != 0) { mutex_exit(&vp->v_interlock); return; } else { dev = vp->v_rdev; type = vp->v_type; mutex_exit(&vp->v_interlock); } vpp = &specfs_hash[SPECHASH(dev)]; mutex_enter(&specfs_lock); for (vq = *vpp; vq != NULL;) { /* If clean or being cleaned, then ignore it. */ mutex_enter(&vq->v_interlock); if ((vq->v_iflag & (VI_CLEAN | VI_XLOCK)) != 0 || vq->v_rdev != dev || vq->v_type != type) { mutex_exit(&vq->v_interlock); vq = vq->v_specnext; continue; } mutex_exit(&specfs_lock); if (vq->v_usecount == 0) { vremfree(vq); vq->v_usecount = 1; } else { atomic_inc_uint(&vq->v_usecount); } vclean(vq, DOCLOSE); vrelel(vq, 0); mutex_enter(&specfs_lock); vq = *vpp; } mutex_exit(&specfs_lock); } /* * sysctl helper routine to return list of supported fstypes */ static int sysctl_vfs_generic_fstypes(SYSCTLFN_ARGS) { char bf[sizeof(((struct statvfs *)NULL)->f_fstypename)]; char *where = oldp; struct vfsops *v; size_t needed, left, slen; int error, first; if (newp != NULL) return (EPERM); if (namelen != 0) return (EINVAL); first = 1; error = 0; needed = 0; left = *oldlenp; sysctl_unlock(); mutex_enter(&vfs_list_lock); LIST_FOREACH(v, &vfs_list, vfs_list) { if (where == NULL) needed += strlen(v->vfs_name) + 1; else { memset(bf, 0, sizeof(bf)); if (first) { strncpy(bf, v->vfs_name, sizeof(bf)); first = 0; } else { bf[0] = ' '; strncpy(bf + 1, v->vfs_name, sizeof(bf) - 1); } bf[sizeof(bf)-1] = '\0'; slen = strlen(bf); if (left < slen + 1) break; /* +1 to copy out the trailing NUL byte */ v->vfs_refcount++; mutex_exit(&vfs_list_lock); error = copyout(bf, where, slen + 1); mutex_enter(&vfs_list_lock); v->vfs_refcount--; if (error) break; where += slen; needed += slen; left -= slen; } } mutex_exit(&vfs_list_lock); sysctl_relock(); *oldlenp = needed; return (error); } /* * Top level filesystem related information gathering. */ SYSCTL_SETUP(sysctl_vfs_setup, "sysctl vfs subtree setup") { sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "vfs", NULL, NULL, 0, NULL, 0, CTL_VFS, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "generic", SYSCTL_DESCR("Non-specific vfs related information"), NULL, 0, NULL, 0, CTL_VFS, VFS_GENERIC, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "usermount", SYSCTL_DESCR("Whether unprivileged users may mount " "filesystems"), NULL, 0, &dovfsusermount, 0, CTL_VFS, VFS_GENERIC, VFS_USERMOUNT, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRING, "fstypes", SYSCTL_DESCR("List of file systems present"), sysctl_vfs_generic_fstypes, 0, NULL, 0, CTL_VFS, VFS_GENERIC, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "magiclinks", SYSCTL_DESCR("Whether \"magic\" symlinks are expanded"), NULL, 0, &vfs_magiclinks, 0, CTL_VFS, VFS_GENERIC, VFS_MAGICLINKS, CTL_EOL); } int kinfo_vdebug = 1; int kinfo_vgetfailed; #define KINFO_VNODESLOP 10 /* * Dump vnode list (via sysctl). * Copyout address of vnode followed by vnode. */ /* ARGSUSED */ int sysctl_kern_vnode(SYSCTLFN_ARGS) { char *where = oldp; size_t *sizep = oldlenp; struct mount *mp, *nmp; vnode_t *vp, *mvp, vbuf; char *bp = where, *savebp; char *ewhere; int error; if (namelen != 0) return (EOPNOTSUPP); if (newp != NULL) return (EPERM); #define VPTRSZ sizeof(vnode_t *) #define VNODESZ sizeof(vnode_t) if (where == NULL) { *sizep = (numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ); return (0); } ewhere = where + *sizep; sysctl_unlock(); mutex_enter(&mountlist_lock); for (mp = CIRCLEQ_FIRST(&mountlist); mp != (void *)&mountlist; mp = nmp) { if (vfs_busy(mp, &nmp)) { continue; } savebp = bp; /* Allocate a marker vnode. */ if ((mvp = vnalloc(mp)) == NULL) { sysctl_relock(); return (ENOMEM); } mutex_enter(&mntvnode_lock); for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = vunmark(mvp)) { vmark(mvp, vp); /* * Check that the vp is still associated with * this filesystem. RACE: could have been * recycled onto the same filesystem. */ if (vp->v_mount != mp || vismarker(vp)) continue; if (bp + VPTRSZ + VNODESZ > ewhere) { (void)vunmark(mvp); mutex_exit(&mntvnode_lock); vnfree(mvp); sysctl_relock(); *sizep = bp - where; return (ENOMEM); } memcpy(&vbuf, vp, VNODESZ); mutex_exit(&mntvnode_lock); if ((error = copyout(vp, bp, VPTRSZ)) || (error = copyout(&vbuf, bp + VPTRSZ, VNODESZ))) { mutex_enter(&mntvnode_lock); (void)vunmark(mvp); mutex_exit(&mntvnode_lock); vnfree(mvp); sysctl_relock(); return (error); } bp += VPTRSZ + VNODESZ; mutex_enter(&mntvnode_lock); } mutex_exit(&mntvnode_lock); vnfree(mvp); vfs_unbusy(mp, false, &nmp); } mutex_exit(&mountlist_lock); sysctl_relock(); *sizep = bp - where; return (0); } /* * Remove clean vnodes from a mountpoint's vnode list. */ void vfs_scrubvnlist(struct mount *mp) { vnode_t *vp, *nvp; retry: mutex_enter(&mntvnode_lock); for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = nvp) { nvp = TAILQ_NEXT(vp, v_mntvnodes); mutex_enter(&vp->v_interlock); if ((vp->v_iflag & VI_CLEAN) != 0) { TAILQ_REMOVE(&mp->mnt_vnodelist, vp, v_mntvnodes); vp->v_mount = NULL; mutex_exit(&mntvnode_lock); mutex_exit(&vp->v_interlock); vfs_destroy(mp); goto retry; } mutex_exit(&vp->v_interlock); } mutex_exit(&mntvnode_lock); } /* * 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 (vp->v_specmountpoint != NULL) return (EBUSY); mutex_enter(&specfs_lock); for (vq = specfs_hash[SPECHASH(vp->v_rdev)]; vq != NULL; vq = vq->v_specnext) { if (vq->v_rdev != vp->v_rdev || vq->v_type != vp->v_type) continue; if (vq->v_specmountpoint != NULL) { error = EBUSY; break; } } mutex_exit(&specfs_lock); return (error); } /* * Unmount all file systems. * We traverse the list in reverse order under the assumption that doing so * will avoid needing to worry about dependencies. */ void vfs_unmountall(struct lwp *l) { struct mount *mp, *nmp; int allerror, error; printf("unmounting file systems..."); for (allerror = 0, mp = CIRCLEQ_LAST(&mountlist); !CIRCLEQ_EMPTY(&mountlist); mp = nmp) { nmp = CIRCLEQ_PREV(mp, mnt_list); #ifdef DEBUG printf("\nunmounting %s (%s)...", mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname); #endif atomic_inc_uint(&mp->mnt_refcnt); if ((error = dounmount(mp, MNT_FORCE, l)) != 0) { printf("unmount of %s failed with error %d\n", mp->mnt_stat.f_mntonname, error); allerror = 1; } } printf(" done\n"); if (allerror) printf("WARNING: some file systems would not unmount\n"); } /* * Sync and unmount file systems before shutting down. */ void vfs_shutdown(void) { struct lwp *l; /* XXX we're certainly not running in lwp0's context! */ l = curlwp; if (l == NULL) l = &lwp0; printf("syncing disks... "); /* remove user processes from run queue */ suspendsched(); (void) spl0(); /* avoid coming back this way again if we panic. */ doing_shutdown = 1; sys_sync(l, NULL, NULL); /* 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"); /* * If we've panic'd, don't make the situation potentially * worse by unmounting the file systems. */ if (panicstr != NULL) return; /* Release inodes held by texts before update. */ #ifdef notdef vnshutdown(); #endif /* Unmount file systems. */ vfs_unmountall(l); } /* * 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%08x -> %d,%d)", rootdev, major(rootdev), 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; default: printf("%s: inappropriate for root file system\n", device_xname(root_device)); return (ENODEV); } /* * If user specified a file system, use it. */ if (mountroot != NULL) { error = (*mountroot)(); 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) { printf("no file system for %s", device_xname(root_device)); if (device_class(root_device) == DV_DISK) printf(" (dev 0x%x)", rootdev); printf("\n"); error = EFTYPE; } done: if (error && device_class(root_device) == DV_DISK) { VOP_CLOSE(rootvp, FREAD, FSCRED); vrele(rootvp); } return (error); } /* * Sham lock manager for vnodes. This is a temporary measure. */ int vlockmgr(struct vnlock *vl, int flags) { KASSERT((flags & ~(LK_CANRECURSE | LK_NOWAIT | LK_TYPE_MASK)) == 0); switch (flags & LK_TYPE_MASK) { case LK_SHARED: if (rw_tryenter(&vl->vl_lock, RW_READER)) { return 0; } if ((flags & LK_NOWAIT) != 0) { return EBUSY; } rw_enter(&vl->vl_lock, RW_READER); return 0; case LK_EXCLUSIVE: if (rw_tryenter(&vl->vl_lock, RW_WRITER)) { return 0; } if ((vl->vl_canrecurse || (flags & LK_CANRECURSE) != 0) && rw_write_held(&vl->vl_lock)) { vl->vl_recursecnt++; return 0; } if ((flags & LK_NOWAIT) != 0) { return EBUSY; } rw_enter(&vl->vl_lock, RW_WRITER); return 0; case LK_RELEASE: if (vl->vl_recursecnt != 0) { KASSERT(rw_write_held(&vl->vl_lock)); vl->vl_recursecnt--; return 0; } rw_exit(&vl->vl_lock); return 0; default: panic("vlockmgr: flags %x", flags); } } int vlockstatus(struct vnlock *vl) { if (rw_write_held(&vl->vl_lock)) { return LK_EXCLUSIVE; } if (rw_read_held(&vl->vl_lock)) { return LK_SHARED; } return 0; }