FreeBSD/Linux Kernel Cross Reference
sys/fs/tmpfs/tmpfs_vnops.c

     /*      $NetBSD: tmpfs_vnops.c,v 1.39 2007/07/23 15:41:01 jmmv Exp $    */
     
     /*-
      * SPDX-License-Identifier: BSD-2-Clause-NetBSD
      *
      * Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
     * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
     * 2005 program.
     *
     * 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.
     */
    
    /*
     * tmpfs vnode interface.
     */
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/dirent.h>
    #include <sys/fcntl.h>
    #include <sys/file.h>
    #include <sys/filio.h>
    #include <sys/limits.h>
    #include <sys/lockf.h>
    #include <sys/lock.h>
    #include <sys/mount.h>
    #include <sys/namei.h>
    #include <sys/priv.h>
    #include <sys/proc.h>
    #include <sys/rwlock.h>
    #include <sys/sched.h>
    #include <sys/smr.h>
    #include <sys/stat.h>
    #include <sys/sysctl.h>
    #include <sys/unistd.h>
    #include <sys/vnode.h>
    #include <security/audit/audit.h>
    #include <security/mac/mac_framework.h>
    
    #include <vm/vm.h>
    #include <vm/vm_param.h>
    #include <vm/vm_object.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pager.h>
    #include <vm/swap_pager.h>
    
    #include <fs/tmpfs/tmpfs_vnops.h>
    #include <fs/tmpfs/tmpfs.h>
    
    SYSCTL_DECL(_vfs_tmpfs);
    VFS_SMR_DECLARE;
    
    static volatile int tmpfs_rename_restarts;
    SYSCTL_INT(_vfs_tmpfs, OID_AUTO, rename_restarts, CTLFLAG_RD,
        __DEVOLATILE(int *, &tmpfs_rename_restarts), 0,
        "Times rename had to restart due to lock contention");
    
    static int
    tmpfs_vn_get_ino_alloc(struct mount *mp, void *arg, int lkflags,
        struct vnode **rvp)
    {
    
            return (tmpfs_alloc_vp(mp, arg, lkflags, rvp));
    }
    
    static int
    tmpfs_lookup1(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp)
    {
            struct tmpfs_dirent *de;
            struct tmpfs_node *dnode, *pnode;
            struct tmpfs_mount *tm;
            int error;
    
            /* Caller assumes responsibility for ensuring access (VEXEC). */
            dnode = VP_TO_TMPFS_DIR(dvp);
           *vpp = NULLVP;
   
           /* We cannot be requesting the parent directory of the root node. */
           MPASS(IMPLIES(dnode->tn_type == VDIR &&
               dnode->tn_dir.tn_parent == dnode,
               !(cnp->cn_flags & ISDOTDOT)));
   
           TMPFS_ASSERT_LOCKED(dnode);
           if (dnode->tn_dir.tn_parent == NULL) {
                   error = ENOENT;
                   goto out;
           }
           if (cnp->cn_flags & ISDOTDOT) {
                   tm = VFS_TO_TMPFS(dvp->v_mount);
                   pnode = dnode->tn_dir.tn_parent;
                   tmpfs_ref_node(pnode);
                   error = vn_vget_ino_gen(dvp, tmpfs_vn_get_ino_alloc,
                       pnode, cnp->cn_lkflags, vpp);
                   tmpfs_free_node(tm, pnode);
                   if (error != 0)
                           goto out;
           } else if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') {
                   VREF(dvp);
                   *vpp = dvp;
                   error = 0;
           } else {
                   de = tmpfs_dir_lookup(dnode, NULL, cnp);
                   if (de != NULL && de->td_node == NULL)
                           cnp->cn_flags |= ISWHITEOUT;
                   if (de == NULL || de->td_node == NULL) {
                           /*
                            * The entry was not found in the directory.
                            * This is OK if we are creating or renaming an
                            * entry and are working on the last component of
                            * the path name.
                            */
                           if ((cnp->cn_flags & ISLASTCN) &&
                               (cnp->cn_nameiop == CREATE || \
                               cnp->cn_nameiop == RENAME ||
                               (cnp->cn_nameiop == DELETE &&
                               cnp->cn_flags & DOWHITEOUT &&
                               cnp->cn_flags & ISWHITEOUT))) {
                                   error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred,
                                       cnp->cn_thread);
                                   if (error != 0)
                                           goto out;
   
                                   /*
                                    * Keep the component name in the buffer for
                                    * future uses.
                                    */
                                   cnp->cn_flags |= SAVENAME;
   
                                   error = EJUSTRETURN;
                           } else
                                   error = ENOENT;
                   } else {
                           struct tmpfs_node *tnode;
   
                           /*
                            * The entry was found, so get its associated
                            * tmpfs_node.
                            */
                           tnode = de->td_node;
   
                           /*
                            * If we are not at the last path component and
                            * found a non-directory or non-link entry (which
                            * may itself be pointing to a directory), raise
                            * an error.
                            */
                           if ((tnode->tn_type != VDIR &&
                               tnode->tn_type != VLNK) &&
                               !(cnp->cn_flags & ISLASTCN)) {
                                   error = ENOTDIR;
                                   goto out;
                           }
   
                           /*
                            * If we are deleting or renaming the entry, keep
                            * track of its tmpfs_dirent so that it can be
                            * easily deleted later.
                            */
                           if ((cnp->cn_flags & ISLASTCN) &&
                               (cnp->cn_nameiop == DELETE ||
                               cnp->cn_nameiop == RENAME)) {
                                   error = VOP_ACCESS(dvp, VWRITE, cnp->cn_cred,
                                       cnp->cn_thread);
                                   if (error != 0)
                                           goto out;
   
                                   /* Allocate a new vnode on the matching entry. */
                                   error = tmpfs_alloc_vp(dvp->v_mount, tnode,
                                       cnp->cn_lkflags, vpp);
                                   if (error != 0)
                                           goto out;
   
                                   if ((dnode->tn_mode & S_ISTXT) &&
                                     VOP_ACCESS(dvp, VADMIN, cnp->cn_cred,
                                     cnp->cn_thread) && VOP_ACCESS(*vpp, VADMIN,
                                     cnp->cn_cred, cnp->cn_thread)) {
                                           error = EPERM;
                                           vput(*vpp);
                                           *vpp = NULL;
                                           goto out;
                                   }
                                   cnp->cn_flags |= SAVENAME;
                           } else {
                                   error = tmpfs_alloc_vp(dvp->v_mount, tnode,
                                       cnp->cn_lkflags, vpp);
                                   if (error != 0)
                                           goto out;
                           }
                   }
           }
   
           /*
            * Store the result of this lookup in the cache.  Avoid this if the
            * request was for creation, as it does not improve timings on
            * emprical tests.
            */
           if ((cnp->cn_flags & MAKEENTRY) != 0 && tmpfs_use_nc(dvp))
                   cache_enter(dvp, *vpp, cnp);
   
   out:
           /*
            * If there were no errors, *vpp cannot be null and it must be
            * locked.
            */
           MPASS(IFF(error == 0, *vpp != NULLVP && VOP_ISLOCKED(*vpp)));
   
           return (error);
   }
   
   static int
   tmpfs_cached_lookup(struct vop_cachedlookup_args *v)
   {
   
           return (tmpfs_lookup1(v->a_dvp, v->a_vpp, v->a_cnp));
   }
   
   static int
   tmpfs_lookup(struct vop_lookup_args *v)
   {
           struct vnode *dvp = v->a_dvp;
           struct vnode **vpp = v->a_vpp;
           struct componentname *cnp = v->a_cnp;
           int error;
   
           /* Check accessibility of requested node as a first step. */
           error = vn_dir_check_exec(dvp, cnp);
           if (error != 0)
                   return (error);
   
           return (tmpfs_lookup1(dvp, vpp, cnp));
   }
   
   static int
   tmpfs_create(struct vop_create_args *v)
   {
           struct vnode *dvp = v->a_dvp;
           struct vnode **vpp = v->a_vpp;
           struct componentname *cnp = v->a_cnp;
           struct vattr *vap = v->a_vap;
           int error;
   
           MPASS(vap->va_type == VREG || vap->va_type == VSOCK);
   
           error = tmpfs_alloc_file(dvp, vpp, vap, cnp, NULL);
           if (error == 0 && (cnp->cn_flags & MAKEENTRY) != 0 && tmpfs_use_nc(dvp))
                   cache_enter(dvp, *vpp, cnp);
           return (error);
   }
   
   static int
   tmpfs_mknod(struct vop_mknod_args *v)
   {
           struct vnode *dvp = v->a_dvp;
           struct vnode **vpp = v->a_vpp;
           struct componentname *cnp = v->a_cnp;
           struct vattr *vap = v->a_vap;
   
           if (vap->va_type != VBLK && vap->va_type != VCHR &&
               vap->va_type != VFIFO)
                   return (EINVAL);
   
           return (tmpfs_alloc_file(dvp, vpp, vap, cnp, NULL));
   }
   
   struct fileops tmpfs_fnops;
   
   static int
   tmpfs_open(struct vop_open_args *v)
   {
           struct vnode *vp;
           struct tmpfs_node *node;
           struct file *fp;
           int error, mode;
   
           vp = v->a_vp;
           mode = v->a_mode;
           node = VP_TO_TMPFS_NODE(vp);
   
           /*
            * The file is still active but all its names have been removed
            * (e.g. by a "rmdir $(pwd)").  It cannot be opened any more as
            * it is about to die.
            */
           if (node->tn_links < 1)
                   return (ENOENT);
   
           /* If the file is marked append-only, deny write requests. */
           if (node->tn_flags & APPEND && (mode & (FWRITE | O_APPEND)) == FWRITE)
                   error = EPERM;
           else {
                   error = 0;
                   /* For regular files, the call below is nop. */
                   KASSERT(vp->v_type != VREG || (node->tn_reg.tn_aobj->flags &
                       OBJ_DEAD) == 0, ("dead object"));
                   vnode_create_vobject(vp, node->tn_size, v->a_td);
           }
   
           fp = v->a_fp;
           MPASS(fp == NULL || fp->f_data == NULL);
           if (error == 0 && fp != NULL && vp->v_type == VREG) {
                   tmpfs_ref_node(node);
                   finit_vnode(fp, mode, node, &tmpfs_fnops);
           }
   
           return (error);
   }
   
   static int
   tmpfs_close(struct vop_close_args *v)
   {
           struct vnode *vp = v->a_vp;
   
           /* Update node times. */
           tmpfs_update(vp);
   
           return (0);
   }
   
   int
   tmpfs_fo_close(struct file *fp, struct thread *td)
   {
           struct tmpfs_node *node;
   
           node = fp->f_data;
           if (node != NULL) {
                   MPASS(node->tn_type == VREG);
                   tmpfs_free_node(node->tn_reg.tn_tmp, node);
           }
           return (vnops.fo_close(fp, td));
   }
   
   /*
    * VOP_FPLOOKUP_VEXEC routines are subject to special circumstances, see
    * the comment above cache_fplookup for details.
    */
   int
   tmpfs_fplookup_vexec(struct vop_fplookup_vexec_args *v)
   {
           struct vnode *vp;
           struct tmpfs_node *node;
           struct ucred *cred;
           mode_t all_x, mode;
   
           vp = v->a_vp;
           node = VP_TO_TMPFS_NODE_SMR(vp);
           if (__predict_false(node == NULL))
                   return (EAGAIN);
   
           all_x = S_IXUSR | S_IXGRP | S_IXOTH;
           mode = atomic_load_short(&node->tn_mode);
           if (__predict_true((mode & all_x) == all_x))
                   return (0);
   
           cred = v->a_cred;
           return (vaccess_vexec_smr(mode, node->tn_uid, node->tn_gid, cred));
   }
   
   int
   tmpfs_access(struct vop_access_args *v)
   {
           struct vnode *vp = v->a_vp;
           accmode_t accmode = v->a_accmode;
           struct ucred *cred = v->a_cred;
           mode_t all_x = S_IXUSR | S_IXGRP | S_IXOTH;
           int error;
           struct tmpfs_node *node;
   
           MPASS(VOP_ISLOCKED(vp));
   
           node = VP_TO_TMPFS_NODE(vp);
   
           /*
            * Common case path lookup.
            */
           if (__predict_true(accmode == VEXEC && (node->tn_mode & all_x) == all_x))
                   return (0);
   
           switch (vp->v_type) {
           case VDIR:
                   /* FALLTHROUGH */
           case VLNK:
                   /* FALLTHROUGH */
           case VREG:
                   if (accmode & VWRITE && vp->v_mount->mnt_flag & MNT_RDONLY) {
                           error = EROFS;
                           goto out;
                   }
                   break;
   
           case VBLK:
                   /* FALLTHROUGH */
           case VCHR:
                   /* FALLTHROUGH */
           case VSOCK:
                   /* FALLTHROUGH */
           case VFIFO:
                   break;
   
           default:
                   error = EINVAL;
                   goto out;
           }
   
           if (accmode & VWRITE && node->tn_flags & IMMUTABLE) {
                   error = EPERM;
                   goto out;
           }
   
           error = vaccess(vp->v_type, node->tn_mode, node->tn_uid, node->tn_gid,
               accmode, cred);
   
   out:
           MPASS(VOP_ISLOCKED(vp));
   
           return (error);
   }
   
   int
   tmpfs_stat(struct vop_stat_args *v)
   {
           struct vnode *vp = v->a_vp;
           struct stat *sb = v->a_sb;
           struct tmpfs_node *node;
           int error;
   
           node = VP_TO_TMPFS_NODE(vp);
   
           tmpfs_update_getattr(vp);
   
           error = vop_stat_helper_pre(v);
           if (__predict_false(error))
                   return (error);
   
           sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
           sb->st_ino = node->tn_id;
           sb->st_mode = node->tn_mode | VTTOIF(vp->v_type);
           sb->st_nlink = node->tn_links;
           sb->st_uid = node->tn_uid;
           sb->st_gid = node->tn_gid;
           sb->st_rdev = (vp->v_type == VBLK || vp->v_type == VCHR) ?
                   node->tn_rdev : NODEV;
           sb->st_size = node->tn_size;
           sb->st_atim.tv_sec = node->tn_atime.tv_sec;
           sb->st_atim.tv_nsec = node->tn_atime.tv_nsec;
           sb->st_mtim.tv_sec = node->tn_mtime.tv_sec;
           sb->st_mtim.tv_nsec = node->tn_mtime.tv_nsec;
           sb->st_ctim.tv_sec = node->tn_ctime.tv_sec;
           sb->st_ctim.tv_nsec = node->tn_ctime.tv_nsec;
           sb->st_birthtim.tv_sec = node->tn_birthtime.tv_sec;
           sb->st_birthtim.tv_nsec = node->tn_birthtime.tv_nsec;
           sb->st_blksize = PAGE_SIZE;
           sb->st_flags = node->tn_flags;
           sb->st_gen = node->tn_gen;
           if (vp->v_type == VREG) {
   #ifdef __ILP32__
                   vm_object_t obj = node->tn_reg.tn_aobj;
   
                   /* Handle torn read */
                   VM_OBJECT_RLOCK(obj);
   #endif
                   sb->st_blocks = ptoa(node->tn_reg.tn_pages);
   #ifdef __ILP32__
                   VM_OBJECT_RUNLOCK(obj);
   #endif
           } else {
                   sb->st_blocks = node->tn_size;
           }
           sb->st_blocks /= S_BLKSIZE;
           return (vop_stat_helper_post(v, error));
   }
   
   int
   tmpfs_getattr(struct vop_getattr_args *v)
   {
           struct vnode *vp = v->a_vp;
           struct vattr *vap = v->a_vap;
           struct tmpfs_node *node;
   
           node = VP_TO_TMPFS_NODE(vp);
   
           tmpfs_update_getattr(vp);
   
           vap->va_type = vp->v_type;
           vap->va_mode = node->tn_mode;
           vap->va_nlink = node->tn_links;
           vap->va_uid = node->tn_uid;
           vap->va_gid = node->tn_gid;
           vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
           vap->va_fileid = node->tn_id;
           vap->va_size = node->tn_size;
           vap->va_blocksize = PAGE_SIZE;
           vap->va_atime = node->tn_atime;
           vap->va_mtime = node->tn_mtime;
           vap->va_ctime = node->tn_ctime;
           vap->va_birthtime = node->tn_birthtime;
           vap->va_gen = node->tn_gen;
           vap->va_flags = node->tn_flags;
           vap->va_rdev = (vp->v_type == VBLK || vp->v_type == VCHR) ?
               node->tn_rdev : NODEV;
           if (vp->v_type == VREG) {
   #ifdef __ILP32__
                   vm_object_t obj = node->tn_reg.tn_aobj;
   
                   VM_OBJECT_RLOCK(obj);
   #endif
                   vap->va_bytes = ptoa(node->tn_reg.tn_pages);
   #ifdef __ILP32__
                   VM_OBJECT_RUNLOCK(obj);
   #endif
           } else {
                   vap->va_bytes = node->tn_size;
           }
           vap->va_filerev = 0;
   
           return (0);
   }
   
   int
   tmpfs_setattr(struct vop_setattr_args *v)
   {
           struct vnode *vp = v->a_vp;
           struct vattr *vap = v->a_vap;
           struct ucred *cred = v->a_cred;
           struct thread *td = curthread;
   
           int error;
   
           MPASS(VOP_ISLOCKED(vp));
           ASSERT_VOP_IN_SEQC(vp);
   
           error = 0;
   
           /* Abort if any unsettable attribute is given. */
           if (vap->va_type != VNON ||
               vap->va_nlink != VNOVAL ||
               vap->va_fsid != VNOVAL ||
               vap->va_fileid != VNOVAL ||
               vap->va_blocksize != VNOVAL ||
               vap->va_gen != VNOVAL ||
               vap->va_rdev != VNOVAL ||
               vap->va_bytes != VNOVAL)
                   error = EINVAL;
   
           if (error == 0 && (vap->va_flags != VNOVAL))
                   error = tmpfs_chflags(vp, vap->va_flags, cred, td);
   
           if (error == 0 && (vap->va_size != VNOVAL))
                   error = tmpfs_chsize(vp, vap->va_size, cred, td);
   
           if (error == 0 && (vap->va_uid != VNOVAL || vap->va_gid != VNOVAL))
                   error = tmpfs_chown(vp, vap->va_uid, vap->va_gid, cred, td);
   
           if (error == 0 && (vap->va_mode != (mode_t)VNOVAL))
                   error = tmpfs_chmod(vp, vap->va_mode, cred, td);
   
           if (error == 0 && ((vap->va_atime.tv_sec != VNOVAL &&
               vap->va_atime.tv_nsec != VNOVAL) ||
               (vap->va_mtime.tv_sec != VNOVAL &&
               vap->va_mtime.tv_nsec != VNOVAL) ||
               (vap->va_birthtime.tv_sec != VNOVAL &&
               vap->va_birthtime.tv_nsec != VNOVAL)))
                   error = tmpfs_chtimes(vp, vap, cred, td);
   
           /*
            * Update the node times.  We give preference to the error codes
            * generated by this function rather than the ones that may arise
            * from tmpfs_update.
            */
           tmpfs_update(vp);
   
           MPASS(VOP_ISLOCKED(vp));
   
           return (error);
   }
   
   static int
   tmpfs_read(struct vop_read_args *v)
   {
           struct vnode *vp;
           struct uio *uio;
           struct tmpfs_node *node;
   
           vp = v->a_vp;
           if (vp->v_type != VREG)
                   return (EISDIR);
           uio = v->a_uio;
           if (uio->uio_offset < 0)
                   return (EINVAL);
           node = VP_TO_TMPFS_NODE(vp);
           tmpfs_set_accessed(VFS_TO_TMPFS(vp->v_mount), node);
           return (uiomove_object(node->tn_reg.tn_aobj, node->tn_size, uio));
   }
   
   static int
   tmpfs_read_pgcache(struct vop_read_pgcache_args *v)
   {
           struct vnode *vp;
           struct tmpfs_node *node;
           vm_object_t object;
           off_t size;
           int error;
   
           vp = v->a_vp;
           VNPASS((vn_irflag_read(vp) & VIRF_PGREAD) != 0, vp);
   
           if (v->a_uio->uio_offset < 0)
                   return (EINVAL);
   
           error = EJUSTRETURN;
           vfs_smr_enter();
   
           node = VP_TO_TMPFS_NODE_SMR(vp);
           if (node == NULL)
                   goto out_smr;
           MPASS(node->tn_type == VREG);
           MPASS(node->tn_refcount >= 1);
           object = node->tn_reg.tn_aobj;
           if (object == NULL)
                   goto out_smr;
   
           MPASS(object->type == tmpfs_pager_type);
           MPASS((object->flags & (OBJ_ANON | OBJ_DEAD | OBJ_SWAP)) ==
               OBJ_SWAP);
           if (!VN_IS_DOOMED(vp)) {
                   /* size cannot become shorter due to rangelock. */
                   size = node->tn_size;
                   tmpfs_set_accessed(node->tn_reg.tn_tmp, node);
                   vfs_smr_exit();
                   error = uiomove_object(object, size, v->a_uio);
                   return (error);
           }
   out_smr:
           vfs_smr_exit();
           return (error);
   }
   
   static int
   tmpfs_write(struct vop_write_args *v)
   {
           struct vnode *vp;
           struct uio *uio;
           struct tmpfs_node *node;
           off_t oldsize;
           ssize_t r;
           int error, ioflag;
           mode_t newmode;
   
           vp = v->a_vp;
           uio = v->a_uio;
           ioflag = v->a_ioflag;
           error = 0;
           node = VP_TO_TMPFS_NODE(vp);
           oldsize = node->tn_size;
   
           if (uio->uio_offset < 0 || vp->v_type != VREG)
                   return (EINVAL);
           if (uio->uio_resid == 0)
                   return (0);
           if (ioflag & IO_APPEND)
                   uio->uio_offset = node->tn_size;
           error = vn_rlimit_fsizex(vp, uio, VFS_TO_TMPFS(vp->v_mount)->
               tm_maxfilesize, &r, uio->uio_td);
           if (error != 0) {
                   vn_rlimit_fsizex_res(uio, r);
                   return (error);
           }
   
           if (uio->uio_offset + uio->uio_resid > node->tn_size) {
                   error = tmpfs_reg_resize(vp, uio->uio_offset + uio->uio_resid,
                       FALSE);
                   if (error != 0)
                           goto out;
           }
   
           error = uiomove_object(node->tn_reg.tn_aobj, node->tn_size, uio);
           node->tn_status |= TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED;
           node->tn_accessed = true;
           if (node->tn_mode & (S_ISUID | S_ISGID)) {
                   if (priv_check_cred(v->a_cred, PRIV_VFS_RETAINSUGID)) {
                           newmode = node->tn_mode & ~(S_ISUID | S_ISGID);
                           vn_seqc_write_begin(vp);
                           atomic_store_short(&node->tn_mode, newmode);
                           vn_seqc_write_end(vp);
                   }
           }
           if (error != 0)
                   (void)tmpfs_reg_resize(vp, oldsize, TRUE);
   
   out:
           MPASS(IMPLIES(error == 0, uio->uio_resid == 0));
           MPASS(IMPLIES(error != 0, oldsize == node->tn_size));
   
           vn_rlimit_fsizex_res(uio, r);
           return (error);
   }
   
   static int
   tmpfs_fsync(struct vop_fsync_args *v)
   {
           struct vnode *vp = v->a_vp;
   
           MPASS(VOP_ISLOCKED(vp));
   
           tmpfs_check_mtime(vp);
           tmpfs_update(vp);
   
           return (0);
   }
   
   static int
   tmpfs_remove(struct vop_remove_args *v)
   {
           struct vnode *dvp = v->a_dvp;
           struct vnode *vp = v->a_vp;
   
           int error;
           struct tmpfs_dirent *de;
           struct tmpfs_mount *tmp;
           struct tmpfs_node *dnode;
           struct tmpfs_node *node;
   
           MPASS(VOP_ISLOCKED(dvp));
           MPASS(VOP_ISLOCKED(vp));
   
           if (vp->v_type == VDIR) {
                   error = EISDIR;
                   goto out;
           }
   
           dnode = VP_TO_TMPFS_DIR(dvp);
           node = VP_TO_TMPFS_NODE(vp);
           tmp = VFS_TO_TMPFS(vp->v_mount);
           de = tmpfs_dir_lookup(dnode, node, v->a_cnp);
           MPASS(de != NULL);
   
           /* Files marked as immutable or append-only cannot be deleted. */
           if ((node->tn_flags & (IMMUTABLE | APPEND | NOUNLINK)) ||
               (dnode->tn_flags & APPEND)) {
                   error = EPERM;
                   goto out;
           }
   
           /* Remove the entry from the directory; as it is a file, we do not
            * have to change the number of hard links of the directory. */
           tmpfs_dir_detach(dvp, de);
           if (v->a_cnp->cn_flags & DOWHITEOUT)
                   tmpfs_dir_whiteout_add(dvp, v->a_cnp);
   
           /* Free the directory entry we just deleted.  Note that the node
            * referred by it will not be removed until the vnode is really
            * reclaimed. */
           tmpfs_free_dirent(tmp, de);
   
           node->tn_status |= TMPFS_NODE_CHANGED;
           node->tn_accessed = true;
           error = 0;
   
   out:
           return (error);
   }
   
   static int
   tmpfs_link(struct vop_link_args *v)
   {
           struct vnode *dvp = v->a_tdvp;
           struct vnode *vp = v->a_vp;
           struct componentname *cnp = v->a_cnp;
   
           int error;
           struct tmpfs_dirent *de;
           struct tmpfs_node *node;
   
           MPASS(VOP_ISLOCKED(dvp));
           MPASS(cnp->cn_flags & HASBUF);
           MPASS(dvp != vp); /* XXX When can this be false? */
           node = VP_TO_TMPFS_NODE(vp);
   
           /* Ensure that we do not overflow the maximum number of links imposed
            * by the system. */
           MPASS(node->tn_links <= TMPFS_LINK_MAX);
           if (node->tn_links == TMPFS_LINK_MAX) {
                   error = EMLINK;
                   goto out;
           }
   
           /* We cannot create links of files marked immutable or append-only. */
           if (node->tn_flags & (IMMUTABLE | APPEND)) {
                   error = EPERM;
                   goto out;
           }
   
           /* Allocate a new directory entry to represent the node. */
           error = tmpfs_alloc_dirent(VFS_TO_TMPFS(vp->v_mount), node,
               cnp->cn_nameptr, cnp->cn_namelen, &de);
           if (error != 0)
                   goto out;
   
           /* Insert the new directory entry into the appropriate directory. */
           if (cnp->cn_flags & ISWHITEOUT)
                   tmpfs_dir_whiteout_remove(dvp, cnp);
           tmpfs_dir_attach(dvp, de);
   
           /* vp link count has changed, so update node times. */
           node->tn_status |= TMPFS_NODE_CHANGED;
           tmpfs_update(vp);
   
           error = 0;
   
   out:
           return (error);
   }
   
   /*
    * We acquire all but fdvp locks using non-blocking acquisitions.  If we
    * fail to acquire any lock in the path we will drop all held locks,
    * acquire the new lock in a blocking fashion, and then release it and
    * restart the rename.  This acquire/release step ensures that we do not
    * spin on a lock waiting for release.  On error release all vnode locks
    * and decrement references the way tmpfs_rename() would do.
    */
   static int
   tmpfs_rename_relock(struct vnode *fdvp, struct vnode **fvpp,
       struct vnode *tdvp, struct vnode **tvpp,
       struct componentname *fcnp, struct componentname *tcnp)
   {
           struct vnode *nvp;
           struct mount *mp;
           struct tmpfs_dirent *de;
           int error, restarts = 0;
   
           VOP_UNLOCK(tdvp);
           if (*tvpp != NULL && *tvpp != tdvp)
                   VOP_UNLOCK(*tvpp);
           mp = fdvp->v_mount;
   
   relock:
           restarts += 1;
           error = vn_lock(fdvp, LK_EXCLUSIVE);
           if (error)
                   goto releout;
           if (vn_lock(tdvp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
                   VOP_UNLOCK(fdvp);
                   error = vn_lock(tdvp, LK_EXCLUSIVE);
                   if (error)
                           goto releout;
                   VOP_UNLOCK(tdvp);
                   goto relock;
           }
           /*
            * Re-resolve fvp to be certain it still exists and fetch the
            * correct vnode.
            */
           de = tmpfs_dir_lookup(VP_TO_TMPFS_DIR(fdvp), NULL, fcnp);
           if (de == NULL) {
                   VOP_UNLOCK(fdvp);
                   VOP_UNLOCK(tdvp);
                   if ((fcnp->cn_flags & ISDOTDOT) != 0 ||
                       (fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.'))
                           error = EINVAL;
                   else
                           error = ENOENT;
                   goto releout;
           }
           error = tmpfs_alloc_vp(mp, de->td_node, LK_EXCLUSIVE | LK_NOWAIT, &nvp);
           if (error != 0) {
                   VOP_UNLOCK(fdvp);
                   VOP_UNLOCK(tdvp);
                   if (error != EBUSY)
                           goto releout;
                   error = tmpfs_alloc_vp(mp, de->td_node, LK_EXCLUSIVE, &nvp);
                   if (error != 0)
                           goto releout;
                   VOP_UNLOCK(nvp);
                   /*
                    * Concurrent rename race.
                    */
                   if (nvp == tdvp) {
                           vrele(nvp);
                           error = EINVAL;
                           goto releout;
                   }
                   vrele(*fvpp);
                   *fvpp = nvp;
                   goto relock;
           }
           vrele(*fvpp);
           *fvpp = nvp;
           VOP_UNLOCK(*fvpp);
           /*
            * Re-resolve tvp and acquire the vnode lock if present.
            */
           de = tmpfs_dir_lookup(VP_TO_TMPFS_DIR(tdvp), NULL, tcnp);
           /*
            * If tvp disappeared we just carry on.
            */
           if (de == NULL && *tvpp != NULL) {
                   vrele(*tvpp);
                   *tvpp = NULL;
           }
           /*
            * Get the tvp ino if the lookup succeeded.  We may have to restart
            * if the non-blocking acquire fails.
            */
           if (de != NULL) {
                   nvp = NULL;
                   error = tmpfs_alloc_vp(mp, de->td_node,
                       LK_EXCLUSIVE | LK_NOWAIT, &nvp);
                   if (*tvpp != NULL)
                           vrele(*tvpp);
                   *tvpp = nvp;
                   if (error != 0) {
                           VOP_UNLOCK(fdvp);
                           VOP_UNLOCK(tdvp);
                           if (error != EBUSY)
                                   goto releout;
                           error = tmpfs_alloc_vp(mp, de->td_node, LK_EXCLUSIVE,
                               &nvp);
                           if (error != 0)
                                   goto releout;
                           VOP_UNLOCK(nvp);
                           /*
                            * fdvp contains fvp, thus tvp (=fdvp) is not empty.
                            */
                           if (nvp == fdvp) {
                                   error = ENOTEMPTY;
                                   goto releout;
                           }
                           goto relock;
                   }
           }
           tmpfs_rename_restarts += restarts;
   
           return (0);
   
   releout:
           vrele(fdvp);
           vrele(*fvpp);
           vrele(tdvp);
           if (*tvpp != NULL)
                   vrele(*tvpp);
           tmpfs_rename_restarts += restarts;
   
           return (error);
   }
   
   static int
   tmpfs_rename(struct vop_rename_args *v)
   {
           struct vnode *fdvp = v->a_fdvp;
           struct vnode *fvp = v->a_fvp;
           struct componentname *fcnp = v->a_fcnp;
           struct vnode *tdvp = v->a_tdvp;
           struct vnode *tvp = v->a_tvp;
           struct componentname *tcnp = v->a_tcnp;
           char *newname;
           struct tmpfs_dirent *de;
           struct tmpfs_mount *tmp;
           struct tmpfs_node *fdnode;
           struct tmpfs_node *fnode;
           struct tmpfs_node *tnode;
           struct tmpfs_node *tdnode;
           int error;
           bool want_seqc_end;
   
           MPASS(VOP_ISLOCKED(tdvp));
           MPASS(IMPLIES(tvp != NULL, VOP_ISLOCKED(tvp)));
           MPASS(fcnp->cn_flags & HASBUF);
           MPASS(tcnp->cn_flags & HASBUF);
   
           want_seqc_end = false;
   
           /*
            * Disallow cross-device renames.
            * XXX Why isn't this done by the caller?
            */
          if (fvp->v_mount != tdvp->v_mount ||
              (tvp != NULL && fvp->v_mount != tvp->v_mount)) {
                  error = EXDEV;
                  goto out;
          }
  
          /* If source and target are the same file, there is nothing to do. */
          if (fvp == tvp) {
                  error = 0;
                  goto out;
          }
  
          /*
           * If we need to move the directory between entries, lock the
           * source so that we can safely operate on it.
           */
          if (fdvp != tdvp && fdvp != tvp) {
                  if (vn_lock(fdvp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
                          error = tmpfs_rename_relock(fdvp, &fvp, tdvp, &tvp,
                              fcnp, tcnp);
                          if (error != 0)
                                  return (error);
                          ASSERT_VOP_ELOCKED(fdvp,
                              "tmpfs_rename: fdvp not locked");
                          ASSERT_VOP_ELOCKED(tdvp,
                              "tmpfs_rename: tdvp not locked");
                          if (tvp != NULL)
                                  ASSERT_VOP_ELOCKED(tvp,
                                      "tmpfs_rename: tvp not locked");
                          if (fvp == tvp) {
                                  error = 0;
                                  goto out_locked;
                          }
                  }
          }
  
          if (tvp != NULL)
                  vn_seqc_write_begin(tvp);
          vn_seqc_write_begin(tdvp);
          vn_seqc_write_begin(fvp);
          vn_seqc_write_begin(fdvp);
          want_seqc_end = true;
  
          tmp = VFS_TO_TMPFS(tdvp->v_mount);
          tdnode = VP_TO_TMPFS_DIR(tdvp);
          tnode = (tvp == NULL) ? NULL : VP_TO_TMPFS_NODE(tvp);
          fdnode = VP_TO_TMPFS_DIR(fdvp);
          fnode = VP_TO_TMPFS_NODE(fvp);
          de = tmpfs_dir_lookup(fdnode, fnode, fcnp);
  
          /*
           * Entry can disappear before we lock fdvp,
           * also avoid manipulating '.' and '..' entries.
           */
          if (de == NULL) {
                  if ((fcnp->cn_flags & ISDOTDOT) != 0 ||
                      (fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.'))
                          error = EINVAL;
                  else
                          error = ENOENT;
                  goto out_locked;
          }
          MPASS(de->td_node == fnode);
  
          /*
           * If re-naming a directory to another preexisting directory
           * ensure that the target directory is empty so that its
           * removal causes no side effects.
           * Kern_rename guarantees the destination to be a directory
           * if the source is one.
           */
          if (tvp != NULL) {
                  MPASS(tnode != NULL);
  
                  if ((tnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) ||
                      (tdnode->tn_flags & (APPEND | IMMUTABLE))) {
                          error = EPERM;
                          goto out_locked;
                  }
  
                  if (fnode->tn_type == VDIR && tnode->tn_type == VDIR) {
                          if (tnode->tn_size > 0) {
                                  error = ENOTEMPTY;
                                  goto out_locked;
                          }
                  } else if (fnode->tn_type == VDIR && tnode->tn_type != VDIR) {
                          error = ENOTDIR;
                          goto out_locked;
                  } else if (fnode->tn_type != VDIR && tnode->tn_type == VDIR) {
                          error = EISDIR;
                          goto out_locked;
                  } else {
                          MPASS(fnode->tn_type != VDIR &&
                                  tnode->tn_type != VDIR);
                  }
          }
  
          if ((fnode->tn_flags & (NOUNLINK | IMMUTABLE | APPEND))
              || (fdnode->tn_flags & (APPEND | IMMUTABLE))) {
                  error = EPERM;
                  goto out_locked;
          }
  
          /*
           * Ensure that we have enough memory to hold the new name, if it
           * has to be changed.
           */
          if (fcnp->cn_namelen != tcnp->cn_namelen ||
              bcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fcnp->cn_namelen) != 0) {
                  newname = malloc(tcnp->cn_namelen, M_TMPFSNAME, M_WAITOK);
          } else
                  newname = NULL;
  
          /*
           * If the node is being moved to another directory, we have to do
           * the move.
           */
          if (fdnode != tdnode) {
                  /*
                   * In case we are moving a directory, we have to adjust its
                   * parent to point to the new parent.
                   */
                  if (de->td_node->tn_type == VDIR) {
                          struct tmpfs_node *n;
  
                          /*
                           * Ensure the target directory is not a child of the
                           * directory being moved.  Otherwise, we'd end up
                           * with stale nodes.
                           */
                          n = tdnode;
                          /*
                           * TMPFS_LOCK guaranties that no nodes are freed while
                           * traversing the list. Nodes can only be marked as
                           * removed: tn_parent == NULL.
                           */
                          TMPFS_LOCK(tmp);
                          TMPFS_NODE_LOCK(n);
                          while (n != n->tn_dir.tn_parent) {
                                  struct tmpfs_node *parent;
  
                                  if (n == fnode) {
                                          TMPFS_NODE_UNLOCK(n);
                                          TMPFS_UNLOCK(tmp);
                                          error = EINVAL;
                                          if (newname != NULL)
                                                      free(newname, M_TMPFSNAME);
                                          goto out_locked;
                                  }
                                  parent = n->tn_dir.tn_parent;
                                  TMPFS_NODE_UNLOCK(n);
                                  if (parent == NULL) {
                                          n = NULL;
                                          break;
                                  }
                                  TMPFS_NODE_LOCK(parent);
                                  if (parent->tn_dir.tn_parent == NULL) {
                                          TMPFS_NODE_UNLOCK(parent);
                                          n = NULL;
                                          break;
                                  }
                                  n = parent;
                          }
                          TMPFS_UNLOCK(tmp);
                          if (n == NULL) {
                                  error = EINVAL;
                                  if (newname != NULL)
                                              free(newname, M_TMPFSNAME);
                                  goto out_locked;
                          }
                          TMPFS_NODE_UNLOCK(n);
  
                          /* Adjust the parent pointer. */
                          TMPFS_VALIDATE_DIR(fnode);
                          TMPFS_NODE_LOCK(de->td_node);
                          de->td_node->tn_dir.tn_parent = tdnode;
                          TMPFS_NODE_UNLOCK(de->td_node);
  
                          /*
                           * As a result of changing the target of the '..'
                           * entry, the link count of the source and target
                           * directories has to be adjusted.
                           */
                          TMPFS_NODE_LOCK(tdnode);
                          TMPFS_ASSERT_LOCKED(tdnode);
                          tdnode->tn_links++;
                          TMPFS_NODE_UNLOCK(tdnode);
  
                          TMPFS_NODE_LOCK(fdnode);
                          TMPFS_ASSERT_LOCKED(fdnode);
                          fdnode->tn_links--;
                          TMPFS_NODE_UNLOCK(fdnode);
                  }
          }
  
          /*
           * Do the move: just remove the entry from the source directory
           * and insert it into the target one.
           */
          tmpfs_dir_detach(fdvp, de);
  
          if (fcnp->cn_flags & DOWHITEOUT)
                  tmpfs_dir_whiteout_add(fdvp, fcnp);
          if (tcnp->cn_flags & ISWHITEOUT)
                  tmpfs_dir_whiteout_remove(tdvp, tcnp);
  
          /*
           * If the name has changed, we need to make it effective by changing
           * it in the directory entry.
           */
          if (newname != NULL) {
                  MPASS(tcnp->cn_namelen <= MAXNAMLEN);
  
                  free(de->ud.td_name, M_TMPFSNAME);
                  de->ud.td_name = newname;
                  tmpfs_dirent_init(de, tcnp->cn_nameptr, tcnp->cn_namelen);
  
                  fnode->tn_status |= TMPFS_NODE_CHANGED;
                  tdnode->tn_status |= TMPFS_NODE_MODIFIED;
          }
  
          /*
           * If we are overwriting an entry, we have to remove the old one
           * from the target directory.
           */
          if (tvp != NULL) {
                  struct tmpfs_dirent *tde;
  
                  /* Remove the old entry from the target directory. */
                  tde = tmpfs_dir_lookup(tdnode, tnode, tcnp);
                  tmpfs_dir_detach(tdvp, tde);
  
                  /*
                   * Free the directory entry we just deleted.  Note that the
                   * node referred by it will not be removed until the vnode is
                   * really reclaimed.
                   */
                  tmpfs_free_dirent(VFS_TO_TMPFS(tvp->v_mount), tde);
          }
  
          tmpfs_dir_attach(tdvp, de);
  
          if (tmpfs_use_nc(fvp)) {
                  cache_vop_rename(fdvp, fvp, tdvp, tvp, fcnp, tcnp);
          }
  
          error = 0;
  
  out_locked:
          if (fdvp != tdvp && fdvp != tvp)
                  VOP_UNLOCK(fdvp);
  
  out:
          if (want_seqc_end) {
                  if (tvp != NULL)
                          vn_seqc_write_end(tvp);
                  vn_seqc_write_end(tdvp);
                  vn_seqc_write_end(fvp);
                  vn_seqc_write_end(fdvp);
          }
  
          /*
           * Release target nodes.
           * XXX: I don't understand when tdvp can be the same as tvp, but
           * other code takes care of this...
           */
          if (tdvp == tvp)
                  vrele(tdvp);
          else
                  vput(tdvp);
          if (tvp != NULL)
                  vput(tvp);
  
          /* Release source nodes. */
          vrele(fdvp);
          vrele(fvp);
  
          return (error);
  }
  
  static int
  tmpfs_mkdir(struct vop_mkdir_args *v)
  {
          struct vnode *dvp = v->a_dvp;
          struct vnode **vpp = v->a_vpp;
          struct componentname *cnp = v->a_cnp;
          struct vattr *vap = v->a_vap;
  
          MPASS(vap->va_type == VDIR);
  
          return (tmpfs_alloc_file(dvp, vpp, vap, cnp, NULL));
  }
  
  static int
  tmpfs_rmdir(struct vop_rmdir_args *v)
  {
          struct vnode *dvp = v->a_dvp;
          struct vnode *vp = v->a_vp;
  
          int error;
          struct tmpfs_dirent *de;
          struct tmpfs_mount *tmp;
          struct tmpfs_node *dnode;
          struct tmpfs_node *node;
  
          MPASS(VOP_ISLOCKED(dvp));
          MPASS(VOP_ISLOCKED(vp));
  
          tmp = VFS_TO_TMPFS(dvp->v_mount);
          dnode = VP_TO_TMPFS_DIR(dvp);
          node = VP_TO_TMPFS_DIR(vp);
  
          /* Directories with more than two entries ('.' and '..') cannot be
           * removed. */
           if (node->tn_size > 0) {
                   error = ENOTEMPTY;
                   goto out;
           }
  
          if ((dnode->tn_flags & APPEND)
              || (node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND))) {
                  error = EPERM;
                  goto out;
          }
  
          /* This invariant holds only if we are not trying to remove "..".
            * We checked for that above so this is safe now. */
          MPASS(node->tn_dir.tn_parent == dnode);
  
          /* Get the directory entry associated with node (vp).  This was
           * filled by tmpfs_lookup while looking up the entry. */
          de = tmpfs_dir_lookup(dnode, node, v->a_cnp);
          MPASS(TMPFS_DIRENT_MATCHES(de,
              v->a_cnp->cn_nameptr,
              v->a_cnp->cn_namelen));
  
          /* Check flags to see if we are allowed to remove the directory. */
          if ((dnode->tn_flags & APPEND) != 0 ||
              (node->tn_flags & (NOUNLINK | IMMUTABLE | APPEND)) != 0) {
                  error = EPERM;
                  goto out;
          }
  
          /* Detach the directory entry from the directory (dnode). */
          tmpfs_dir_detach(dvp, de);
          if (v->a_cnp->cn_flags & DOWHITEOUT)
                  tmpfs_dir_whiteout_add(dvp, v->a_cnp);
  
          /* No vnode should be allocated for this entry from this point */
          TMPFS_NODE_LOCK(node);
          node->tn_links--;
          node->tn_dir.tn_parent = NULL;
          node->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
          node->tn_accessed = true;
  
          TMPFS_NODE_UNLOCK(node);
  
          TMPFS_NODE_LOCK(dnode);
          dnode->tn_links--;
          dnode->tn_status |= TMPFS_NODE_CHANGED | TMPFS_NODE_MODIFIED;
          dnode->tn_accessed = true;
          TMPFS_NODE_UNLOCK(dnode);
  
          if (tmpfs_use_nc(dvp)) {
                  cache_vop_rmdir(dvp, vp);
          }
  
          /* Free the directory entry we just deleted.  Note that the node
           * referred by it will not be removed until the vnode is really
           * reclaimed. */
          tmpfs_free_dirent(tmp, de);
  
          /* Release the deleted vnode (will destroy the node, notify
           * interested parties and clean it from the cache). */
  
          dnode->tn_status |= TMPFS_NODE_CHANGED;
          tmpfs_update(dvp);
  
          error = 0;
  
  out:
          return (error);
  }
  
  static int
  tmpfs_symlink(struct vop_symlink_args *v)
  {
          struct vnode *dvp = v->a_dvp;
          struct vnode **vpp = v->a_vpp;
          struct componentname *cnp = v->a_cnp;
          struct vattr *vap = v->a_vap;
          const char *target = v->a_target;
  
  #ifdef notyet /* XXX FreeBSD BUG: kern_symlink is not setting VLNK */
          MPASS(vap->va_type == VLNK);
  #else
          vap->va_type = VLNK;
  #endif
  
          return (tmpfs_alloc_file(dvp, vpp, vap, cnp, target));
  }
  
  static int
  tmpfs_readdir(struct vop_readdir_args *va)
  {
          struct vnode *vp;
          struct uio *uio;
          struct tmpfs_mount *tm;
          struct tmpfs_node *node;
          u_long **cookies;
          int *eofflag, *ncookies;
          ssize_t startresid;
          int error, maxcookies;
  
          vp = va->a_vp;
          uio = va->a_uio;
          eofflag = va->a_eofflag;
          cookies = va->a_cookies;
          ncookies = va->a_ncookies;
  
          /* This operation only makes sense on directory nodes. */
          if (vp->v_type != VDIR)
                  return (ENOTDIR);
  
          maxcookies = 0;
          node = VP_TO_TMPFS_DIR(vp);
          tm = VFS_TO_TMPFS(vp->v_mount);
  
          startresid = uio->uio_resid;
  
          /* Allocate cookies for NFS and compat modules. */
          if (cookies != NULL && ncookies != NULL) {
                  maxcookies = howmany(node->tn_size,
                      sizeof(struct tmpfs_dirent)) + 2;
                  *cookies = malloc(maxcookies * sizeof(**cookies), M_TEMP,
                      M_WAITOK);
                  *ncookies = 0;
          }
  
          if (cookies == NULL)
                  error = tmpfs_dir_getdents(tm, node, uio, 0, NULL, NULL);
          else
                  error = tmpfs_dir_getdents(tm, node, uio, maxcookies, *cookies,
                      ncookies);
  
          /* Buffer was filled without hitting EOF. */
          if (error == EJUSTRETURN)
                  error = (uio->uio_resid != startresid) ? 0 : EINVAL;
  
          if (error != 0 && cookies != NULL && ncookies != NULL) {
                  free(*cookies, M_TEMP);
                  *cookies = NULL;
                  *ncookies = 0;
          }
  
          if (eofflag != NULL)
                  *eofflag =
                      (error == 0 && uio->uio_offset == TMPFS_DIRCOOKIE_EOF);
  
          return (error);
  }
  
  static int
  tmpfs_readlink(struct vop_readlink_args *v)
  {
          struct vnode *vp = v->a_vp;
          struct uio *uio = v->a_uio;
  
          int error;
          struct tmpfs_node *node;
  
          MPASS(uio->uio_offset == 0);
          MPASS(vp->v_type == VLNK);
  
          node = VP_TO_TMPFS_NODE(vp);
  
          error = uiomove(node->tn_link_target, MIN(node->tn_size, uio->uio_resid),
              uio);
          tmpfs_set_accessed(VFS_TO_TMPFS(vp->v_mount), node);
  
          return (error);
  }
  
  /*
   * VOP_FPLOOKUP_SYMLINK routines are subject to special circumstances, see
   * the comment above cache_fplookup for details.
   *
   * Check tmpfs_alloc_node for tmpfs-specific synchronisation notes.
   */
  static int
  tmpfs_fplookup_symlink(struct vop_fplookup_symlink_args *v)
  {
          struct vnode *vp;
          struct tmpfs_node *node;
          char *symlink;
  
          vp = v->a_vp;
          node = VP_TO_TMPFS_NODE_SMR(vp);
          if (__predict_false(node == NULL))
                  return (EAGAIN);
          if (!atomic_load_char(&node->tn_link_smr))
                  return (EAGAIN);
          symlink = atomic_load_ptr(&node->tn_link_target);
          if (symlink == NULL)
                  return (EAGAIN);
  
          return (cache_symlink_resolve(v->a_fpl, symlink, node->tn_size));
  }
  
  static int
  tmpfs_inactive(struct vop_inactive_args *v)
  {
          struct vnode *vp;
          struct tmpfs_node *node;
  
          vp = v->a_vp;
          node = VP_TO_TMPFS_NODE(vp);
          if (node->tn_links == 0)
                  vrecycle(vp);
          else
                  tmpfs_check_mtime(vp);
          return (0);
  }
  
  static int
  tmpfs_need_inactive(struct vop_need_inactive_args *ap)
  {
          struct vnode *vp;
          struct tmpfs_node *node;
          struct vm_object *obj;
  
          vp = ap->a_vp;
          node = VP_TO_TMPFS_NODE(vp);
          if (node->tn_links == 0)
                  goto need;
          if (vp->v_type == VREG) {
                  obj = vp->v_object;
                  if (obj->generation != obj->cleangeneration)
                          goto need;
          }
          return (0);
  need:
          return (1);
  }
  
  int
  tmpfs_reclaim(struct vop_reclaim_args *v)
  {
          struct vnode *vp;
          struct tmpfs_mount *tmp;
          struct tmpfs_node *node;
          bool unlock;
  
          vp = v->a_vp;
          node = VP_TO_TMPFS_NODE(vp);
          tmp = VFS_TO_TMPFS(vp->v_mount);
  
          if (vp->v_type == VREG)
                  tmpfs_destroy_vobject(vp, node->tn_reg.tn_aobj);
          vp->v_object = NULL;
  
          TMPFS_LOCK(tmp);
          TMPFS_NODE_LOCK(node);
          tmpfs_free_vp(vp);
  
          /*
           * If the node referenced by this vnode was deleted by the user,
           * we must free its associated data structures (now that the vnode
           * is being reclaimed).
           */
          unlock = true;
          if (node->tn_links == 0 &&
              (node->tn_vpstate & TMPFS_VNODE_ALLOCATING) == 0) {
                  node->tn_vpstate = TMPFS_VNODE_DOOMED;
                  unlock = !tmpfs_free_node_locked(tmp, node, true);
          }
  
          if (unlock) {
                  TMPFS_NODE_UNLOCK(node);
                  TMPFS_UNLOCK(tmp);
          }
  
          MPASS(vp->v_data == NULL);
          return (0);
  }
  
  int
  tmpfs_print(struct vop_print_args *v)
  {
          struct vnode *vp = v->a_vp;
  
          struct tmpfs_node *node;
  
          node = VP_TO_TMPFS_NODE(vp);
  
          printf("tag VT_TMPFS, tmpfs_node %p, flags 0x%lx, links %jd\n",
              node, node->tn_flags, (uintmax_t)node->tn_links);
          printf("\tmode 0%o, owner %d, group %d, size %jd, status 0x%x\n",
              node->tn_mode, node->tn_uid, node->tn_gid,
              (intmax_t)node->tn_size, node->tn_status);
  
          if (vp->v_type == VFIFO)
                  fifo_printinfo(vp);
  
          printf("\n");
  
          return (0);
  }
  
  int
  tmpfs_pathconf(struct vop_pathconf_args *v)
  {
          struct vnode *vp = v->a_vp;
          int name = v->a_name;
          long *retval = v->a_retval;
  
          int error;
  
          error = 0;
  
          switch (name) {
          case _PC_LINK_MAX:
                  *retval = TMPFS_LINK_MAX;
                  break;
  
          case _PC_SYMLINK_MAX:
                  *retval = MAXPATHLEN;
                  break;
  
          case _PC_NAME_MAX:
                  *retval = NAME_MAX;
                  break;
  
          case _PC_PIPE_BUF:
                  if (vp->v_type == VDIR || vp->v_type == VFIFO)
                          *retval = PIPE_BUF;
                  else
                          error = EINVAL;
                  break;
  
          case _PC_CHOWN_RESTRICTED:
                  *retval = 1;
                  break;
  
          case _PC_NO_TRUNC:
                  *retval = 1;
                  break;
  
          case _PC_SYNC_IO:
                  *retval = 1;
                  break;
  
          case _PC_FILESIZEBITS:
                  *retval = 64;
                  break;
  
          case _PC_MIN_HOLE_SIZE:
                  *retval = PAGE_SIZE;
                  break;
  
          default:
                  error = vop_stdpathconf(v);
          }
  
          return (error);
  }
  
  static int
  tmpfs_vptofh(struct vop_vptofh_args *ap)
  /*
  vop_vptofh {
          IN struct vnode *a_vp;
          IN struct fid *a_fhp;
  };
  */
  {
          struct tmpfs_fid_data tfd;
          struct tmpfs_node *node;
          struct fid *fhp;
  
          node = VP_TO_TMPFS_NODE(ap->a_vp);
          fhp = ap->a_fhp;
          fhp->fid_len = sizeof(tfd);
  
          /*
           * Copy into fid_data from the stack to avoid unaligned pointer use.
           * See the comment in sys/mount.h on struct fid for details.
           */
          tfd.tfd_id = node->tn_id;
          tfd.tfd_gen = node->tn_gen;
          memcpy(fhp->fid_data, &tfd, fhp->fid_len);
  
          return (0);
  }
  
  static int
  tmpfs_whiteout(struct vop_whiteout_args *ap)
  {
          struct vnode *dvp = ap->a_dvp;
          struct componentname *cnp = ap->a_cnp;
          struct tmpfs_dirent *de;
  
          switch (ap->a_flags) {
          case LOOKUP:
                  return (0);
          case CREATE:
                  de = tmpfs_dir_lookup(VP_TO_TMPFS_DIR(dvp), NULL, cnp);
                  if (de != NULL)
                          return (de->td_node == NULL ? 0 : EEXIST);
                  return (tmpfs_dir_whiteout_add(dvp, cnp));
          case DELETE:
                  tmpfs_dir_whiteout_remove(dvp, cnp);
                  return (0);
          default:
                  panic("tmpfs_whiteout: unknown op");
          }
  }
  
  static int
  tmpfs_vptocnp_dir(struct tmpfs_node *tn, struct tmpfs_node *tnp,
      struct tmpfs_dirent **pde)
  {
          struct tmpfs_dir_cursor dc;
          struct tmpfs_dirent *de;
  
          for (de = tmpfs_dir_first(tnp, &dc); de != NULL;
               de = tmpfs_dir_next(tnp, &dc)) {
                  if (de->td_node == tn) {
                          *pde = de;
                          return (0);
                  }
          }
          return (ENOENT);
  }
  
  static int
  tmpfs_vptocnp_fill(struct vnode *vp, struct tmpfs_node *tn,
      struct tmpfs_node *tnp, char *buf, size_t *buflen, struct vnode **dvp)
  {
          struct tmpfs_dirent *de;
          int error, i;
  
          error = vn_vget_ino_gen(vp, tmpfs_vn_get_ino_alloc, tnp, LK_SHARED,
              dvp);
          if (error != 0)
                  return (error);
          error = tmpfs_vptocnp_dir(tn, tnp, &de);
          if (error == 0) {
                  i = *buflen;
                  i -= de->td_namelen;
                  if (i < 0) {
                          error = ENOMEM;
                  } else {
                          bcopy(de->ud.td_name, buf + i, de->td_namelen);
                          *buflen = i;
                  }
          }
          if (error == 0) {
                  if (vp != *dvp)
                          VOP_UNLOCK(*dvp);
          } else {
                  if (vp != *dvp)
                          vput(*dvp);
                  else
                          vrele(vp);
          }
          return (error);
  }
  
  static int
  tmpfs_vptocnp(struct vop_vptocnp_args *ap)
  {
          struct vnode *vp, **dvp;
          struct tmpfs_node *tn, *tnp, *tnp1;
          struct tmpfs_dirent *de;
          struct tmpfs_mount *tm;
          char *buf;
          size_t *buflen;
          int error;
  
          vp = ap->a_vp;
          dvp = ap->a_vpp;
          buf = ap->a_buf;
          buflen = ap->a_buflen;
  
          tm = VFS_TO_TMPFS(vp->v_mount);
          tn = VP_TO_TMPFS_NODE(vp);
          if (tn->tn_type == VDIR) {
                  tnp = tn->tn_dir.tn_parent;
                  if (tnp == NULL)
                          return (ENOENT);
                  tmpfs_ref_node(tnp);
                  error = tmpfs_vptocnp_fill(vp, tn, tn->tn_dir.tn_parent, buf,
                      buflen, dvp);
                  tmpfs_free_node(tm, tnp);
                  return (error);
          }
  restart:
          TMPFS_LOCK(tm);
  restart_locked:
          LIST_FOREACH_SAFE(tnp, &tm->tm_nodes_used, tn_entries, tnp1) {
                  if (tnp->tn_type != VDIR)
                          continue;
                  TMPFS_NODE_LOCK(tnp);
                  tmpfs_ref_node(tnp);
  
                  /*
                   * tn_vnode cannot be instantiated while we hold the
                   * node lock, so the directory cannot be changed while
                   * we iterate over it.  Do this to avoid instantiating
                   * vnode for directories which cannot point to our
                   * node.
                   */
                  error = tnp->tn_vnode == NULL ? tmpfs_vptocnp_dir(tn, tnp,
                      &de) : 0;
  
                  if (error == 0) {
                          TMPFS_NODE_UNLOCK(tnp);
                          TMPFS_UNLOCK(tm);
                          error = tmpfs_vptocnp_fill(vp, tn, tnp, buf, buflen,
                              dvp);
                          if (error == 0) {
                                  tmpfs_free_node(tm, tnp);
                                  return (0);
                          }
                          if (VN_IS_DOOMED(vp)) {
                                  tmpfs_free_node(tm, tnp);
                                  return (ENOENT);
                          }
                          TMPFS_LOCK(tm);
                          TMPFS_NODE_LOCK(tnp);
                  }
                  if (tmpfs_free_node_locked(tm, tnp, false)) {
                          goto restart;
                  } else {
                          KASSERT(tnp->tn_refcount > 0,
                              ("node %p refcount zero", tnp));
                          if (tnp->tn_attached) {
                                  tnp1 = LIST_NEXT(tnp, tn_entries);
                                  TMPFS_NODE_UNLOCK(tnp);
                          } else {
                                  TMPFS_NODE_UNLOCK(tnp);
                                  goto restart_locked;
                          }
                  }
          }
          TMPFS_UNLOCK(tm);
          return (ENOENT);
  }
  
  static off_t
  tmpfs_seek_data_locked(vm_object_t obj, off_t noff)
  {
          vm_page_t m;
          vm_pindex_t p, p_m, p_swp;
  
          p = OFF_TO_IDX(noff);
          m = vm_page_find_least(obj, p);
  
          /*
           * Microoptimize the most common case for SEEK_DATA, where
           * there is no hole and the page is resident.
           */
          if (m != NULL && vm_page_any_valid(m) && m->pindex == p)
                  return (noff);
  
          p_swp = swap_pager_find_least(obj, p);
          if (p_swp == p)
                  return (noff);
  
          p_m = m == NULL ? obj->size : m->pindex;
          return (IDX_TO_OFF(MIN(p_m, p_swp)));
  }
  
  static off_t
  tmpfs_seek_next(off_t noff)
  {
          return (noff + PAGE_SIZE - (noff & PAGE_MASK));
  }
  
  static int
  tmpfs_seek_clamp(struct tmpfs_node *tn, off_t *noff, bool seekdata)
  {
          if (*noff < tn->tn_size)
                  return (0);
          if (seekdata)
                  return (ENXIO);
          *noff = tn->tn_size;
          return (0);
  }
  
  static off_t
  tmpfs_seek_hole_locked(vm_object_t obj, off_t noff)
  {
          vm_page_t m;
          vm_pindex_t p, p_swp;
  
          for (;; noff = tmpfs_seek_next(noff)) {
                  /*
                   * Walk over the largest sequential run of the valid pages.
                   */
                  for (m = vm_page_lookup(obj, OFF_TO_IDX(noff));
                      m != NULL && vm_page_any_valid(m);
                      m = vm_page_next(m), noff = tmpfs_seek_next(noff))
                          ;
  
                  /*
                   * Found a hole in the object's page queue.  Check if
                   * there is a hole in the swap at the same place.
                   */
                  p = OFF_TO_IDX(noff);
                  p_swp = swap_pager_find_least(obj, p);
                  if (p_swp != p) {
                          noff = IDX_TO_OFF(p);
                          break;
                  }
          }
          return (noff);
  }
  
  static int
  tmpfs_seek_datahole(struct vnode *vp, off_t *off, bool seekdata)
  {
          struct tmpfs_node *tn;
          vm_object_t obj;
          off_t noff;
          int error;
  
          if (vp->v_type != VREG)
                  return (ENOTTY);
          tn = VP_TO_TMPFS_NODE(vp);
          noff = *off;
          if (noff < 0)
                  return (ENXIO);
          error = tmpfs_seek_clamp(tn, &noff, seekdata);
          if (error != 0)
                  return (error);
          obj = tn->tn_reg.tn_aobj;
  
          VM_OBJECT_RLOCK(obj);
          noff = seekdata ? tmpfs_seek_data_locked(obj, noff) :
              tmpfs_seek_hole_locked(obj, noff);
          VM_OBJECT_RUNLOCK(obj);
  
          error = tmpfs_seek_clamp(tn, &noff, seekdata);
          if (error == 0)
                  *off = noff;
          return (error);
  }
  
  static int
  tmpfs_ioctl(struct vop_ioctl_args *ap)
  {
          struct vnode *vp = ap->a_vp;
          int error = 0;
  
          switch (ap->a_command) {
          case FIOSEEKDATA:
          case FIOSEEKHOLE:
                  error = vn_lock(vp, LK_SHARED);
                  if (error != 0) {
                          error = EBADF;
                          break;
                  }
                  error = tmpfs_seek_datahole(vp, (off_t *)ap->a_data,
                      ap->a_command == FIOSEEKDATA);
                  VOP_UNLOCK(vp);
                  break;
          default:
                  error = ENOTTY;
                  break;
          }
          return (error);
  }
  
  /*
   * Vnode operations vector used for files stored in a tmpfs file system.
   */
  struct vop_vector tmpfs_vnodeop_entries = {
          .vop_default =                  &default_vnodeops,
          .vop_lookup =                   vfs_cache_lookup,
          .vop_cachedlookup =             tmpfs_cached_lookup,
          .vop_create =                   tmpfs_create,
          .vop_mknod =                    tmpfs_mknod,
          .vop_open =                     tmpfs_open,
          .vop_close =                    tmpfs_close,
          .vop_fplookup_vexec =           tmpfs_fplookup_vexec,
          .vop_fplookup_symlink =         tmpfs_fplookup_symlink,
          .vop_access =                   tmpfs_access,
          .vop_stat =                     tmpfs_stat,
          .vop_getattr =                  tmpfs_getattr,
          .vop_setattr =                  tmpfs_setattr,
          .vop_read =                     tmpfs_read,
          .vop_read_pgcache =             tmpfs_read_pgcache,
          .vop_write =                    tmpfs_write,
          .vop_fsync =                    tmpfs_fsync,
          .vop_remove =                   tmpfs_remove,
          .vop_link =                     tmpfs_link,
          .vop_rename =                   tmpfs_rename,
          .vop_mkdir =                    tmpfs_mkdir,
          .vop_rmdir =                    tmpfs_rmdir,
          .vop_symlink =                  tmpfs_symlink,
          .vop_readdir =                  tmpfs_readdir,
          .vop_readlink =                 tmpfs_readlink,
          .vop_inactive =                 tmpfs_inactive,
          .vop_need_inactive =            tmpfs_need_inactive,
          .vop_reclaim =                  tmpfs_reclaim,
          .vop_print =                    tmpfs_print,
          .vop_pathconf =                 tmpfs_pathconf,
          .vop_vptofh =                   tmpfs_vptofh,
          .vop_whiteout =                 tmpfs_whiteout,
          .vop_bmap =                     VOP_EOPNOTSUPP,
          .vop_vptocnp =                  tmpfs_vptocnp,
          .vop_lock1 =                    vop_lock,
          .vop_unlock =                   vop_unlock,
          .vop_islocked =                 vop_islocked,
          .vop_ioctl =                    tmpfs_ioctl,
  };
  VFS_VOP_VECTOR_REGISTER(tmpfs_vnodeop_entries);
  
  /*
   * Same vector for mounts which do not use namecache.
   */
  struct vop_vector tmpfs_vnodeop_nonc_entries = {
          .vop_default =                  &tmpfs_vnodeop_entries,
          .vop_lookup =                   tmpfs_lookup,
  };
  VFS_VOP_VECTOR_REGISTER(tmpfs_vnodeop_nonc_entries);

Cache object: 97bb58aaf9a7e5968c2a5aa7c90d80b3