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1/* $OpenBSD: tmpfs.h,v 1.11 2025/10/15 06:52:50 mvs Exp $ */
2/* $NetBSD: tmpfs.h,v 1.45 2011/09/27 01:10:43 christos Exp $ */
3
4/*
5 * Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
10 * 2005 program.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#ifndef _TMPFS_TMPFS_H_
35#define _TMPFS_TMPFS_H_
36
37#if !defined(_KERNEL) && !defined(_KMEMUSER)
38#error "not supposed to be exposed to userland"
39#endif
40
41#include <sys/dirent.h>
42#include <sys/mount.h>
43#include <sys/pool.h>
44#include <sys/queue.h>
45#include <sys/stdint.h>
46#include <sys/rwlock.h>
47#include <sys/lock.h>
48
49#include <uvm/uvm_extern.h>
50
51/*
52 * Internal representation of a tmpfs directory entry.
53 *
54 * All fields are protected by vnode lock.
55 */
56typedef struct tmpfs_dirent {
57 TAILQ_ENTRY(tmpfs_dirent) td_entries;
58
59 /* Pointer to the inode this entry refers to. */
60 struct tmpfs_node * td_node;
61
62 /* Sequence number, see tmpfs_dir_getseq(). */
63 uint64_t td_seq;
64
65 /* Name and its length. */
66 char * td_name;
67 uint16_t td_namelen;
68} tmpfs_dirent_t;
69
70TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
71
72/*
73 * Internal representation of a tmpfs file system node -- inode.
74 *
75 * This structure is split in two parts: one holds attributes common
76 * to all file types and the other holds data that is only applicable to
77 * a particular type.
78 *
79 * All fields are protected by vnode lock. The vnode association itself
80 * is protected by tmpfs_node_t::tn_nlock.
81 */
82typedef struct tmpfs_node {
83 LIST_ENTRY(tmpfs_node) tn_entries;
84
85 /*
86 * Each inode has a corresponding vnode. It is a bi-directional
87 * association. Whenever vnode is allocated, its v_data field is
88 * set to the inode it reference, and tmpfs_node_t::tn_vnode is
89 * set to point to the said vnode.
90 *
91 * Further attempts to allocate a vnode for this same node will
92 * result in returning a new reference to the value stored in
93 * tn_vnode. It may be NULL when the node is unused (that is,
94 * no vnode has been allocated or it has been reclaimed).
95 */
96 struct rwlock tn_nlock; /* node lock */
97 struct rrwlock tn_vlock; /* vnode lock */
98 struct vnode * tn_vnode;
99
100 /* Directory entry. Only a hint, since hard link can have multiple. */
101 tmpfs_dirent_t * tn_dirent_hint;
102
103 /* The inode type: VBLK, VCHR, VDIR, VFIFO, VLNK, VREG or VSOCK. */
104 enum vtype tn_type;
105
106 /* Inode identifier and generation number. */
107 ino_t tn_id;
108 unsigned long tn_gen;
109
110 /* The inode size. */
111 off_t tn_size;
112
113 /* Generic node attributes. */
114 uid_t tn_uid;
115 gid_t tn_gid;
116 mode_t tn_mode;
117 int tn_flags;
118 nlink_t tn_links;
119 struct timespec tn_atime;
120 struct timespec tn_mtime;
121 struct timespec tn_ctime;
122 struct timespec tn_birthtime;
123
124 /* Head of byte-level lock list (used by tmpfs_advlock). */
125 struct lockf_state * tn_lockf;
126
127 union {
128 /* Type case: VBLK or VCHR. */
129 struct {
130 dev_t tn_rdev;
131 } tn_dev;
132
133 /* Type case: VDIR. */
134 struct {
135 /* Parent directory (root inode points to itself). */
136 struct tmpfs_node * tn_parent;
137
138 /* List of directory entries. */
139 struct tmpfs_dir tn_dir;
140
141 /* Last given sequence number. */
142 uint64_t tn_next_seq;
143
144 /*
145 * Pointer of the last directory entry returned
146 * by the readdir(3) operation.
147 */
148 struct tmpfs_dirent * tn_readdir_lastp;
149 } tn_dir;
150
151 /* Type case: VLNK. */
152 struct tn_lnk {
153 /* The link's target. */
154 char * tn_link;
155 } tn_lnk;
156
157 /* Type case: VREG. */
158 struct tn_reg {
159 /* Underlying UVM object to store contents. */
160 struct uvm_object * tn_aobj;
161 size_t tn_aobj_pages;
162 vaddr_t tn_aobj_pgptr;
163 voff_t tn_aobj_pgnum;
164 } tn_reg;
165 } tn_spec;
166
167#define tn_uobj tn_spec.tn_reg.tn_aobj
168#define tn_pgptr tn_spec.tn_reg.tn_aobj_pgptr
169#define tn_pgnum tn_spec.tn_reg.tn_aobj_pgnum
170
171} tmpfs_node_t;
172
173#if defined(_KERNEL)
174
175#include <lib/libkern/libkern.h> /* for KASSERT() */
176
177LIST_HEAD(tmpfs_node_list, tmpfs_node);
178
179
180#define TMPFS_MAXNAMLEN 255
181/* Validate maximum td_namelen length. */
182/* CTASSERT(TMPFS_MAXNAMLEN < UINT16_MAX); */
183
184/*
185 * Reserved values for the virtual entries (the first must be 0) and EOF.
186 * The start/end of the incremental range, see tmpfs_dir_getseq().
187 */
188#define TMPFS_DIRSEQ_DOT 0
189#define TMPFS_DIRSEQ_DOTDOT 1
190#define TMPFS_DIRSEQ_EOF 2
191
192#define TMPFS_DIRSEQ_START 3 /* inclusive */
193#define TMPFS_DIRSEQ_END UINT64_MAX /* exclusive */
194
195/* Mark to indicate that the number is not set. */
196#define TMPFS_DIRSEQ_NONE UINT64_MAX
197
198/* Can we still append entries to a directory? */
199#define TMPFS_DIRSEQ_FULL(dnode) \
200 ((dnode)->tn_spec.tn_dir.tn_next_seq == TMPFS_DIRSEQ_END)
201
202/* Status flags. */
203#define TMPFS_NODE_ACCESSED 0x01
204#define TMPFS_NODE_MODIFIED 0x02
205#define TMPFS_NODE_CHANGED 0x04
206
207#define TMPFS_NODE_STATUSALL \
208 (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED)
209
210/*
211 * Bit indicating vnode reclamation.
212 * We abuse tmpfs_node_t::tn_gen for that.
213 */
214#define TMPFS_NODE_GEN_MASK (~0UL >> 1)
215#define TMPFS_RECLAIMING_BIT (~TMPFS_NODE_GEN_MASK)
216
217#define TMPFS_NODE_RECLAIMING(node) \
218 (((node)->tn_gen & TMPFS_RECLAIMING_BIT) != 0)
219
220#define TMPFS_NODE_GEN(node) \
221 ((node)->tn_gen & TMPFS_NODE_GEN_MASK)
222
223/*
224 * Internal representation of a tmpfs mount point.
225 */
226typedef struct tmpfs_mount {
227 /* Limit and number of bytes in use by the file system. */
228 uint64_t tm_mem_limit;
229 uint64_t tm_bytes_used;
230 /* Highest allocated inode number. */
231 uint64_t tm_highest_inode;
232 struct rwlock tm_acc_lock;
233
234 /* Pointer to the root inode. */
235 tmpfs_node_t * tm_root;
236
237 /* Maximum number of possible nodes for this file system. */
238 unsigned int tm_nodes_max;
239
240 /* Number of nodes currently allocated. */
241 unsigned int tm_nodes_cnt;
242
243 /* List of inodes and the lock protecting it. */
244 struct rwlock tm_lock;
245 struct tmpfs_node_list tm_nodes;
246} tmpfs_mount_t;
247
248/*
249 * This structure maps a file identifier to a tmpfs node. Used by the
250 * NFS code.
251 */
252typedef struct tmpfs_fid {
253 uint16_t tf_len;
254 uint16_t tf_pad;
255 uint32_t tf_gen;
256 ino_t tf_id;
257} tmpfs_fid_t;
258
259/*
260 * Prototypes for tmpfs_subr.c.
261 */
262
263int tmpfs_alloc_node(tmpfs_mount_t *, enum vtype, uid_t, gid_t,
264 mode_t, char *, dev_t, tmpfs_node_t **);
265void tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *);
266
267int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
268 struct componentname *, char *);
269
270int tmpfs_vnode_get(struct mount *, tmpfs_node_t *, struct vnode **);
271
272int tmpfs_alloc_dirent(tmpfs_mount_t *, const char *, uint16_t,
273 tmpfs_dirent_t **);
274void tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *);
275void tmpfs_dir_attach(tmpfs_node_t *, tmpfs_dirent_t *,
276 tmpfs_node_t *);
277void tmpfs_dir_detach(tmpfs_node_t *, tmpfs_dirent_t *);
278
279tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *);
280tmpfs_dirent_t *tmpfs_dir_cached(tmpfs_node_t *);
281
282uint64_t tmpfs_dir_getseq(tmpfs_node_t *, tmpfs_dirent_t *);
283tmpfs_dirent_t *tmpfs_dir_lookupbyseq(tmpfs_node_t *, off_t);
284int tmpfs_dir_getdents(tmpfs_node_t *, struct uio *);
285
286int tmpfs_reg_resize(struct vnode *, off_t);
287int tmpfs_truncate(struct vnode *, off_t);
288
289int tmpfs_chflags(struct vnode *, int, struct ucred *, struct proc *);
290int tmpfs_chmod(struct vnode *, mode_t, struct ucred *, struct proc *);
291int tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *, struct proc *);
292int tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *, struct proc *);
293int tmpfs_chtimes(struct vnode *, const struct timespec *,
294 const struct timespec *, int, struct ucred *,
295 struct proc *);
296void tmpfs_update(tmpfs_node_t *, int);
297int tmpfs_zeropg(tmpfs_node_t *, voff_t, vaddr_t);
298int tmpfs_uio_cached(tmpfs_node_t *);
299int tmpfs_uiomove(tmpfs_node_t *, struct uio *, vsize_t);
300void tmpfs_uio_uncache(tmpfs_node_t *);
301void tmpfs_uio_cache(tmpfs_node_t *, voff_t, vaddr_t);
302vaddr_t tmpfs_uio_lookup(tmpfs_node_t *, voff_t);
303
304/*
305 * Prototypes for tmpfs_mem.c.
306 */
307
308void tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t);
309void tmpfs_mntmem_destroy(tmpfs_mount_t *);
310
311uint64_t tmpfs_pages_total(tmpfs_mount_t *);
312uint64_t tmpfs_pages_avail(tmpfs_mount_t *);
313int tmpfs_mem_incr(tmpfs_mount_t *, size_t);
314void tmpfs_mem_decr(tmpfs_mount_t *, size_t);
315
316tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *);
317void tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *);
318
319tmpfs_node_t * tmpfs_node_get(tmpfs_mount_t *);
320void tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *);
321
322char * tmpfs_strname_alloc(tmpfs_mount_t *, size_t);
323void tmpfs_strname_free(tmpfs_mount_t *, char *, size_t);
324int tmpfs_strname_neqlen(struct componentname *, struct componentname *);
325
326/*
327 * Ensures that the node pointed by 'node' is a directory and that its
328 * contents are consistent with respect to directories.
329 */
330#define TMPFS_VALIDATE_DIR(node) \
331 KASSERT((node)->tn_vnode == NULL || VOP_ISLOCKED((node)->tn_vnode)); \
332 KASSERT((node)->tn_type == VDIR); \
333 KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0);
334
335/*
336 * Routines to convert VFS structures to tmpfs internal ones.
337 */
338
339static inline tmpfs_mount_t *
340VFS_TO_TMPFS(struct mount *mp)
341{
342 tmpfs_mount_t *tmp = mp->mnt_data;
343
344 KASSERT(tmp != NULL);
345 return tmp;
346}
347
348static inline tmpfs_node_t *
349VP_TO_TMPFS_DIR(struct vnode *vp)
350{
351 tmpfs_node_t *node = vp->v_data;
352
353 KASSERT(node != NULL);
354 TMPFS_VALIDATE_DIR(node);
355 return node;
356}
357
358#endif /* defined(_KERNEL) */
359
360static __inline tmpfs_node_t *
361VP_TO_TMPFS_NODE(struct vnode *vp)
362{
363 tmpfs_node_t *node = vp->v_data;
364#ifdef KASSERT
365 KASSERT(node != NULL);
366#endif
367 return node;
368}
369
370#endif /* _TMPFS_TMPFS_H_ */