5dc1128656
If tmpfs vnode is only shared locked, tn_status field still needs updates to note the access time modification. Use the same locking scheme as for UFS, protect tn_status with the node interlock + shared vnode lock. Fix nearby style. Noted and reviewed by: mjg Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week
507 lines
16 KiB
C
507 lines
16 KiB
C
/* $NetBSD: tmpfs.h,v 1.26 2007/02/22 06:37:00 thorpej Exp $ */
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/*-
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* Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Julio M. Merino Vidal, developed as part of Google's Summer of Code
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* 2005 program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _FS_TMPFS_TMPFS_H_
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#define _FS_TMPFS_TMPFS_H_
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#include <sys/dirent.h>
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#include <sys/mount.h>
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#include <sys/queue.h>
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#include <sys/vnode.h>
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#include <sys/file.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/malloc.h>
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#include <sys/systm.h>
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#include <sys/tree.h>
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#include <sys/vmmeter.h>
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#include <vm/swap_pager.h>
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MALLOC_DECLARE(M_TMPFSMNT);
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MALLOC_DECLARE(M_TMPFSNAME);
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/*
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* Internal representation of a tmpfs directory entry.
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*/
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LIST_HEAD(tmpfs_dir_duphead, tmpfs_dirent);
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struct tmpfs_dirent {
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/*
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* Depending on td_cookie flag entry can be of 3 types:
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* - regular -- no hash collisions, stored in RB-Tree
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* - duphead -- synthetic linked list head for dup entries
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* - dup -- stored in linked list instead of RB-Tree
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*/
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union {
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/* regular and duphead entry types */
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RB_ENTRY(tmpfs_dirent) td_entries;
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/* dup entry type */
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struct {
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LIST_ENTRY(tmpfs_dirent) entries;
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LIST_ENTRY(tmpfs_dirent) index_entries;
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} td_dup;
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} uh;
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uint32_t td_cookie;
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uint32_t td_hash;
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u_int td_namelen;
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/* Pointer to the node this entry refers to. In case this field
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* is NULL, the node is a whiteout. */
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struct tmpfs_node * td_node;
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union {
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/*
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* The name of the entry, allocated from a string pool. This
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* string is not required to be zero-terminated.
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*/
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char * td_name; /* regular, dup */
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struct tmpfs_dir_duphead td_duphead; /* duphead */
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} ud;
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};
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/* A directory in tmpfs holds a list of directory entries, which in
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* turn point to other files (which can be directories themselves).
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*
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* In tmpfs, this list is managed by a RB-Tree, whose head is defined by
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* the struct tmpfs_dir type.
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*
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* It is important to notice that directories do not have entries for . and
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* .. as other file systems do. These can be generated when requested
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* based on information available by other means, such as the pointer to
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* the node itself in the former case or the pointer to the parent directory
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* in the latter case. This is done to simplify tmpfs's code and, more
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* importantly, to remove redundancy. */
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RB_HEAD(tmpfs_dir, tmpfs_dirent);
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/* Each entry in a directory has a cookie that identifies it. Cookies
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* supersede offsets within directories because, given how tmpfs stores
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* directories in memory, there is no such thing as an offset.
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*
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* The '.', '..' and the end of directory markers have fixed cookies which
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* cannot collide with the cookies generated by other entries. The cookies
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* for the other entries are generated based on the file name hash value or
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* unique number in case of name hash collision.
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*
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* To preserve compatibility cookies are limited to 31 bits.
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*/
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#define TMPFS_DIRCOOKIE_DOT 0
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#define TMPFS_DIRCOOKIE_DOTDOT 1
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#define TMPFS_DIRCOOKIE_EOF 2
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#define TMPFS_DIRCOOKIE_MASK ((off_t)0x3fffffffU)
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#define TMPFS_DIRCOOKIE_MIN ((off_t)0x00000004U)
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#define TMPFS_DIRCOOKIE_DUP ((off_t)0x40000000U)
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#define TMPFS_DIRCOOKIE_DUPHEAD ((off_t)0x80000000U)
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#define TMPFS_DIRCOOKIE_DUP_MIN TMPFS_DIRCOOKIE_DUP
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#define TMPFS_DIRCOOKIE_DUP_MAX \
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(TMPFS_DIRCOOKIE_DUP | TMPFS_DIRCOOKIE_MASK)
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/*
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* Internal representation of a tmpfs file system node.
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*
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* This structure is splitted in two parts: one holds attributes common
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* to all file types and the other holds data that is only applicable to
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* a particular type. The code must be careful to only access those
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* attributes that are actually allowed by the node's type.
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*
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*
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* Below is the key of locks used to protected the fields in the following
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* structures.
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*
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*/
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struct tmpfs_node {
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/* Doubly-linked list entry which links all existing nodes for a
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* single file system. This is provided to ease the removal of
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* all nodes during the unmount operation. */
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LIST_ENTRY(tmpfs_node) tn_entries;
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/* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO',
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* 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode
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* types instead of a custom enumeration is to make things simpler
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* and faster, as we do not need to convert between two types. */
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enum vtype tn_type;
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/* Node identifier. */
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ino_t tn_id;
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/* Node's internal status. This is used by several file system
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* operations to do modifications to the node in a delayed
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* fashion. */
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int tn_status;
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#define TMPFS_NODE_ACCESSED (1 << 1)
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#define TMPFS_NODE_MODIFIED (1 << 2)
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#define TMPFS_NODE_CHANGED (1 << 3)
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/* The node size. It does not necessarily match the real amount
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* of memory consumed by it. */
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off_t tn_size;
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/* Generic node attributes. */
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uid_t tn_uid;
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gid_t tn_gid;
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mode_t tn_mode;
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u_long tn_flags;
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nlink_t tn_links;
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struct timespec tn_atime;
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struct timespec tn_mtime;
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struct timespec tn_ctime;
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struct timespec tn_birthtime;
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unsigned long tn_gen;
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/* As there is a single vnode for each active file within the
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* system, care has to be taken to avoid allocating more than one
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* vnode per file. In order to do this, a bidirectional association
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* is kept between vnodes and nodes.
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*
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* Whenever a vnode is allocated, its v_data field is updated to
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* point to the node it references. At the same time, the node's
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* tn_vnode field is modified to point to the new vnode representing
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* it. Further attempts to allocate a vnode for this same node will
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* result in returning a new reference to the value stored in
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* tn_vnode.
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*
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* May be NULL when the node is unused (that is, no vnode has been
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* allocated for it or it has been reclaimed). */
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struct vnode * tn_vnode;
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/* Interlock to protect tn_vpstate, and tn_status under shared
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* vnode lock.
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*/
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struct mtx tn_interlock;
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/* Identify if current node has vnode assiocate with
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* or allocating vnode.
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*/
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int tn_vpstate;
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/* misc data field for different tn_type node */
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union {
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/* Valid when tn_type == VBLK || tn_type == VCHR. */
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dev_t tn_rdev;
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/* Valid when tn_type == VDIR. */
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struct tn_dir {
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/* Pointer to the parent directory. The root
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* directory has a pointer to itself in this field;
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* this property identifies the root node. */
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struct tmpfs_node * tn_parent;
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/* Head of a tree that links the contents of
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* the directory together. */
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struct tmpfs_dir tn_dirhead;
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/* Head of a list the contains fake directory entries
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* heads, i.e. entries with TMPFS_DIRCOOKIE_DUPHEAD
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* flag. */
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struct tmpfs_dir_duphead tn_dupindex;
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/* Number and pointer of the first directory entry
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* returned by the readdir operation if it were
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* called again to continue reading data from the
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* same directory as before. This is used to speed
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* up reads of long directories, assuming that no
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* more than one read is in progress at a given time.
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* Otherwise, these values are discarded. */
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off_t tn_readdir_lastn;
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struct tmpfs_dirent * tn_readdir_lastp;
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} tn_dir;
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/* Valid when tn_type == VLNK. */
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/* The link's target, allocated from a string pool. */
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char * tn_link;
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/* Valid when tn_type == VREG. */
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struct tn_reg {
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/* The contents of regular files stored in a tmpfs
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* file system are represented by a single anonymous
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* memory object (aobj, for short). The aobj provides
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* direct access to any position within the file,
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* because its contents are always mapped in a
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* contiguous region of virtual memory. It is a task
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* of the memory management subsystem (see uvm(9)) to
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* issue the required page ins or page outs whenever
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* a position within the file is accessed. */
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vm_object_t tn_aobj;
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}tn_reg;
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/* Valid when tn_type = VFIFO */
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struct tn_fifo {
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fo_rdwr_t *tn_fo_read;
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fo_rdwr_t *tn_fo_write;
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}tn_fifo;
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}tn_spec;
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};
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LIST_HEAD(tmpfs_node_list, tmpfs_node);
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#define tn_rdev tn_spec.tn_rdev
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#define tn_dir tn_spec.tn_dir
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#define tn_link tn_spec.tn_link
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#define tn_reg tn_spec.tn_reg
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#define tn_fifo tn_spec.tn_fifo
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#define TMPFS_NODE_LOCK(node) mtx_lock(&(node)->tn_interlock)
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#define TMPFS_NODE_UNLOCK(node) mtx_unlock(&(node)->tn_interlock)
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#define TMPFS_NODE_MTX(node) (&(node)->tn_interlock)
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#define TMPFS_NODE_ASSERT_LOCKED(node) mtx_assert(TMPFS_NODE_MTX(node), \
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MA_OWNED)
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#ifdef INVARIANTS
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#define TMPFS_ASSERT_LOCKED(node) do { \
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MPASS(node != NULL); \
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MPASS(node->tn_vnode != NULL); \
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if (!VOP_ISLOCKED(node->tn_vnode) && \
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!mtx_owned(TMPFS_NODE_MTX(node))) \
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panic("tmpfs: node is not locked: %p", node); \
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} while (0)
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#define TMPFS_ASSERT_ELOCKED(node) do { \
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MPASS((node) != NULL); \
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MPASS((node)->tn_vnode != NULL); \
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mtx_assert(TMPFS_NODE_MTX(node), MA_OWNED); \
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ASSERT_VOP_LOCKED((node)->tn_vnode, "tmpfs"); \
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} while (0)
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#else
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#define TMPFS_ASSERT_LOCKED(node) (void)0
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#define TMPFS_ASSERT_ELOCKED(node) (void)0
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#endif
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#define TMPFS_VNODE_ALLOCATING 1
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#define TMPFS_VNODE_WANT 2
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#define TMPFS_VNODE_DOOMED 4
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#define TMPFS_VNODE_WRECLAIM 8
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/*
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* Internal representation of a tmpfs mount point.
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*/
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struct tmpfs_mount {
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/* Maximum number of memory pages available for use by the file
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* system, set during mount time. This variable must never be
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* used directly as it may be bigger than the current amount of
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* free memory; in the extreme case, it will hold the SIZE_MAX
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* value. */
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size_t tm_pages_max;
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/* Number of pages in use by the file system. */
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size_t tm_pages_used;
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/* Pointer to the node representing the root directory of this
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* file system. */
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struct tmpfs_node * tm_root;
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/* Maximum number of possible nodes for this file system; set
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* during mount time. We need a hard limit on the maximum number
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* of nodes to avoid allocating too much of them; their objects
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* cannot be released until the file system is unmounted.
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* Otherwise, we could easily run out of memory by creating lots
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* of empty files and then simply removing them. */
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ino_t tm_nodes_max;
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/* unrhdr used to allocate inode numbers */
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struct unrhdr * tm_ino_unr;
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/* Number of nodes currently that are in use. */
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ino_t tm_nodes_inuse;
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/* maximum representable file size */
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u_int64_t tm_maxfilesize;
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/* Nodes are organized in two different lists. The used list
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* contains all nodes that are currently used by the file system;
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* i.e., they refer to existing files. The available list contains
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* all nodes that are currently available for use by new files.
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* Nodes must be kept in this list (instead of deleting them)
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* because we need to keep track of their generation number (tn_gen
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* field).
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*
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* Note that nodes are lazily allocated: if the available list is
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* empty and we have enough space to create more nodes, they will be
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* created and inserted in the used list. Once these are released,
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* they will go into the available list, remaining alive until the
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* file system is unmounted. */
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struct tmpfs_node_list tm_nodes_used;
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/* All node lock to protect the node list and tmp_pages_used */
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struct mtx allnode_lock;
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/* Pools used to store file system meta data. These are not shared
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* across several instances of tmpfs for the reasons described in
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* tmpfs_pool.c. */
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uma_zone_t tm_dirent_pool;
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uma_zone_t tm_node_pool;
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/* Read-only status. */
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int tm_ronly;
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};
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#define TMPFS_LOCK(tm) mtx_lock(&(tm)->allnode_lock)
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#define TMPFS_UNLOCK(tm) mtx_unlock(&(tm)->allnode_lock)
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/*
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* This structure maps a file identifier to a tmpfs node. Used by the
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* NFS code.
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*/
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struct tmpfs_fid {
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uint16_t tf_len;
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uint16_t tf_pad;
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ino_t tf_id;
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unsigned long tf_gen;
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};
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#ifdef _KERNEL
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/*
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* Prototypes for tmpfs_subr.c.
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*/
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int tmpfs_alloc_node(struct mount *mp, struct tmpfs_mount *, enum vtype,
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uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *,
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char *, dev_t, struct tmpfs_node **);
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void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *);
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int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
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const char *, u_int, struct tmpfs_dirent **);
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void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *);
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void tmpfs_dirent_init(struct tmpfs_dirent *, const char *, u_int);
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void tmpfs_destroy_vobject(struct vnode *vp, vm_object_t obj);
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int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, int,
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struct vnode **);
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void tmpfs_free_vp(struct vnode *);
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int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
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struct componentname *, char *);
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void tmpfs_check_mtime(struct vnode *);
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void tmpfs_dir_attach(struct vnode *, struct tmpfs_dirent *);
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void tmpfs_dir_detach(struct vnode *, struct tmpfs_dirent *);
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void tmpfs_dir_destroy(struct tmpfs_mount *, struct tmpfs_node *);
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struct tmpfs_dirent * tmpfs_dir_lookup(struct tmpfs_node *node,
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struct tmpfs_node *f,
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struct componentname *cnp);
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int tmpfs_dir_getdents(struct tmpfs_node *, struct uio *, int,
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u_long *, int *);
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int tmpfs_dir_whiteout_add(struct vnode *, struct componentname *);
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void tmpfs_dir_whiteout_remove(struct vnode *, struct componentname *);
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int tmpfs_reg_resize(struct vnode *, off_t, boolean_t);
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int tmpfs_chflags(struct vnode *, u_long, struct ucred *, struct thread *);
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int tmpfs_chmod(struct vnode *, mode_t, struct ucred *, struct thread *);
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int tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *,
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struct thread *);
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int tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *, struct thread *);
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int tmpfs_chtimes(struct vnode *, struct vattr *, struct ucred *cred,
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struct thread *);
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void tmpfs_itimes(struct vnode *, const struct timespec *,
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const struct timespec *);
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void tmpfs_set_status(struct tmpfs_node *node, int status);
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void tmpfs_update(struct vnode *);
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int tmpfs_truncate(struct vnode *, off_t);
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/*
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* Convenience macros to simplify some logical expressions.
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*/
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#define IMPLIES(a, b) (!(a) || (b))
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#define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
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/*
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* Checks that the directory entry pointed by 'de' matches the name 'name'
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* with a length of 'len'.
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*/
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#define TMPFS_DIRENT_MATCHES(de, name, len) \
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(de->td_namelen == len && \
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bcmp((de)->ud.td_name, (name), (de)->td_namelen) == 0)
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/*
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* Ensures that the node pointed by 'node' is a directory and that its
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* contents are consistent with respect to directories.
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*/
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#define TMPFS_VALIDATE_DIR(node) do { \
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MPASS((node)->tn_type == VDIR); \
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MPASS((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \
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} while (0)
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/*
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* Memory management stuff.
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*/
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/*
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* Amount of memory pages to reserve for the system (e.g., to not use by
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* tmpfs).
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*/
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#define TMPFS_PAGES_MINRESERVED (4 * 1024 * 1024 / PAGE_SIZE)
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size_t tmpfs_mem_avail(void);
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size_t tmpfs_pages_used(struct tmpfs_mount *tmp);
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#endif
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/*
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* Macros/functions to convert from generic data structures to tmpfs
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* specific ones.
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*/
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static inline
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struct tmpfs_mount *
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VFS_TO_TMPFS(struct mount *mp)
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{
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struct tmpfs_mount *tmp;
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MPASS((mp) != NULL && (mp)->mnt_data != NULL);
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tmp = (struct tmpfs_mount *)(mp)->mnt_data;
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return tmp;
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}
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static inline
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struct tmpfs_node *
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VP_TO_TMPFS_NODE(struct vnode *vp)
|
|
{
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|
struct tmpfs_node *node;
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|
|
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MPASS((vp) != NULL && (vp)->v_data != NULL);
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node = (struct tmpfs_node *)vp->v_data;
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return node;
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}
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static inline
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|
struct tmpfs_node *
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|
VP_TO_TMPFS_DIR(struct vnode *vp)
|
|
{
|
|
struct tmpfs_node *node;
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|
|
|
node = VP_TO_TMPFS_NODE(vp);
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TMPFS_VALIDATE_DIR(node);
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return node;
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|
}
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#endif /* _FS_TMPFS_TMPFS_H_ */
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