tmpfs.h revision 1.5 1 /* $NetBSD: tmpfs.h,v 1.5 2005/09/23 12:10:32 jmmv Exp $ */
2
3 /*
4 * Copyright (c) 2005 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Julio M. Merino Vidal.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 #if !defined(_TMPFS_H_)
40 # define _TMPFS_H_
41 #else
42 # error "tmpfs.h cannot be included multiple times."
43 #endif
44
45 /* ---------------------------------------------------------------------
46 * KERNEL-SPECIFIC DEFINITIONS
47 * --------------------------------------------------------------------- */
48
49 #if defined(_KERNEL)
50
51 #include <sys/dirent.h>
52 #include <sys/mount.h>
53 #include <sys/queue.h>
54 #include <sys/vnode.h>
55
56 #include <fs/tmpfs/tmpfs_pool.h>
57
58 /* --------------------------------------------------------------------- */
59
60 /*
61 * This structure holds a directory entry.
62 */
63 struct tmpfs_dirent {
64 TAILQ_ENTRY(tmpfs_dirent) td_entries;
65 uint16_t td_namelen;
66 char * td_name;
67 struct tmpfs_node * td_node;
68 };
69 TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
70
71 #define TMPFS_DIRCOOKIE(dirent) ((off_t)(uintptr_t)(dirent))
72 #define TMPFS_DIRCOOKIE_DOT 0
73 #define TMPFS_DIRCOOKIE_DOTDOT 1
74 #define TMPFS_DIRCOOKIE_EOF 2
75
76 /* --------------------------------------------------------------------- */
77
78 /*
79 * This structure represents a node within tmpfs.
80 */
81 struct tmpfs_node {
82 LIST_ENTRY(tmpfs_node) tn_entries;
83
84 enum vtype tn_type;
85 ino_t tn_id;
86
87 #define TMPFS_NODE_ACCESSED (1 << 1)
88 #define TMPFS_NODE_MODIFIED (1 << 2)
89 #define TMPFS_NODE_CHANGED (1 << 3)
90 int tn_status;
91
92 off_t tn_size;
93
94 /* Attributes. */
95 uid_t tn_uid;
96 gid_t tn_gid;
97 mode_t tn_mode;
98 int tn_flags;
99 nlink_t tn_links;
100 struct timespec tn_atime;
101 struct timespec tn_mtime;
102 struct timespec tn_ctime;
103 struct timespec tn_birthtime;
104 unsigned long tn_gen;
105
106 struct vnode * tn_vnode;
107
108 /* Used by tmpfs_lookup to store the affected directory entry during
109 * DELETE and RENAME operations. */
110 struct tmpfs_dirent * tn_lookup_dirent;
111
112 union {
113 /* Valid when tn_type == VBLK || tn_type == VCHR. */
114 struct {
115 dev_t tn_rdev;
116 };
117
118 /* Valid when tn_type == VDIR. */
119 struct {
120 struct tmpfs_node * tn_parent;
121 struct tmpfs_dir tn_dir;
122
123 /* Used by tmpfs_readdir to speed up lookups. */
124 off_t tn_readdir_lastn;
125 struct tmpfs_dirent * tn_readdir_lastp;
126 };
127
128 /* Valid when tn_type == VLNK. */
129 struct {
130 char * tn_link;
131 };
132
133 /* Valid when tn_type == VREG. */
134 struct {
135 struct uvm_object * tn_aobj;
136 size_t tn_aobj_pages;
137 };
138 };
139 };
140 LIST_HEAD(tmpfs_node_list, tmpfs_node);
141
142 /* --------------------------------------------------------------------- */
143
144 /*
145 * This structure holds the information relative to a tmpfs instance.
146 */
147 struct tmpfs_mount {
148 size_t tm_pages_max;
149 size_t tm_pages_used;
150
151 struct tmpfs_node * tm_root;
152
153 ino_t tm_nodes_max;
154 ino_t tm_nodes_last;
155 struct tmpfs_node_list tm_nodes_used;
156 struct tmpfs_node_list tm_nodes_avail;
157
158 struct tmpfs_pool tm_dirent_pool;
159 struct tmpfs_pool tm_node_pool;
160 struct tmpfs_str_pool tm_str_pool;
161 };
162
163 /* --------------------------------------------------------------------- */
164
165 /*
166 * This structure maps a file identifier to a tmpfs node. Used by the
167 * NFS code.
168 */
169 struct tmpfs_fid {
170 uint16_t tf_len;
171 uint16_t tf_pad;
172 ino_t tf_id;
173 unsigned long tf_gen;
174 };
175
176 /* --------------------------------------------------------------------- */
177
178 /*
179 * Prototypes for tmpfs_subr.c.
180 */
181
182 int tmpfs_alloc_node(struct tmpfs_mount *, enum vtype,
183 uid_t uid, gid_t gid, mode_t mode, struct tmpfs_node *,
184 char *, dev_t, struct proc *, struct tmpfs_node **);
185 void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *);
186 int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
187 const char *, uint16_t, struct tmpfs_dirent **);
188 void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *,
189 boolean_t);
190 int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, struct vnode **);
191 void tmpfs_free_vp(struct vnode *);
192 int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
193 struct componentname *, char *);
194 void tmpfs_dir_attach(struct vnode *, struct tmpfs_dirent *);
195 void tmpfs_dir_detach(struct vnode *, struct tmpfs_dirent *);
196 struct tmpfs_dirent * tmpfs_dir_lookup(struct tmpfs_node *node,
197 struct componentname *cnp);
198 int tmpfs_dir_getdotdent(struct tmpfs_node *, struct uio *);
199 int tmpfs_dir_getdotdotdent(struct tmpfs_node *, struct uio *);
200 struct tmpfs_dirent * tmpfs_dir_lookupbycookie(struct tmpfs_node *, off_t);
201 int tmpfs_dir_getdents(struct tmpfs_node *, struct uio *, off_t *);
202 int tmpfs_reg_resize(struct vnode *, off_t);
203 size_t tmpfs_mem_info(boolean_t);
204 int tmpfs_chflags(struct vnode *, int, struct ucred *, struct proc *);
205 int tmpfs_chmod(struct vnode *, mode_t, struct ucred *, struct proc *);
206 int tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *,
207 struct proc *);
208 int tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *, struct proc *);
209 int tmpfs_chtimes(struct vnode *, struct timespec *, struct timespec *,
210 int, struct ucred *, struct proc *);
211
212 /* --------------------------------------------------------------------- */
213
214 /*
215 * Convenience macros to simplify some logical expressions.
216 */
217 #define IMPLIES(a, b) (!(a) || (b))
218 #define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
219
220 /* --------------------------------------------------------------------- */
221
222 /*
223 * Checks that the directory entry pointed by 'de' matches the name 'name'
224 * with a length of 'len'.
225 */
226 #define TMPFS_DIRENT_MATCHES(de, name, len) \
227 (de->td_namelen == (uint16_t)len && \
228 memcmp((de)->td_name, (name), (de)->td_namelen) == 0)
229
230 /* --------------------------------------------------------------------- */
231
232 /*
233 * Ensures that the node pointed by 'node' is a directory and that its
234 * contents are consistent with respect to directories.
235 */
236 #define TMPFS_VALIDATE_DIR(node) \
237 KASSERT((node)->tn_type == VDIR); \
238 KASSERT((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \
239 KASSERT((node)->tn_readdir_lastp == NULL || \
240 TMPFS_DIRCOOKIE((node)->tn_readdir_lastp) == (node)->tn_readdir_lastn);
241
242 /* --------------------------------------------------------------------- */
243
244 /*
245 * Memory management stuff.
246 */
247
248 /* Amount of memory pages to reserve for the system (e.g., to not use by
249 * tmpfs).
250 * XXX: Should this be tunable through sysctl, for instance? */
251 #define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE)
252
253 /* Returns the available memory for the given file system, which can be
254 * its limit (set during mount time) or the amount of free memory, whichever
255 * is lower. */
256 static inline size_t
257 TMPFS_PAGES_MAX(struct tmpfs_mount *tmp)
258 {
259 size_t freepages;
260
261 freepages = tmpfs_mem_info(FALSE);
262 if (freepages < TMPFS_PAGES_RESERVED)
263 freepages = 0;
264 else
265 freepages -= TMPFS_PAGES_RESERVED;
266
267 return MIN(tmp->tm_pages_max, freepages + tmp->tm_pages_used);
268 }
269
270 #define TMPFS_PAGES_AVAIL(tmp) (TMPFS_PAGES_MAX(tmp) - (tmp)->tm_pages_used)
271
272 /* --------------------------------------------------------------------- */
273
274 /*
275 * Macros/functions to convert from generic data structures to tmpfs
276 * specific ones.
277 *
278 * Macros are used when no sanity checks have to be done, as they provide
279 * the fastest conversion. On the other hand, inlined functions are used
280 * when expensive sanity checks are enabled, mostly because the checks
281 * have to be done separately from the return value.
282 */
283
284 #if defined(DIAGNOSTIC)
285 static inline
286 struct tmpfs_mount *
287 VFS_TO_TMPFS(struct mount *mp)
288 {
289 struct tmpfs_mount *tmp;
290
291 KASSERT((mp) != NULL && (mp)->mnt_data != NULL);
292 tmp = (struct tmpfs_mount *)(mp)->mnt_data;
293 KASSERT(TMPFS_PAGES_MAX(tmp) >= tmp->tm_pages_used);
294 return tmp;
295 }
296
297 static inline
298 struct tmpfs_node *
299 VP_TO_TMPFS_NODE(struct vnode *vp)
300 {
301 struct tmpfs_node *node;
302
303 KASSERT((vp) != NULL && (vp)->v_data != NULL);
304 node = (struct tmpfs_node *)vp->v_data;
305 return node;
306 }
307
308 static inline
309 struct tmpfs_node *
310 VP_TO_TMPFS_DIR(struct vnode *vp)
311 {
312 struct tmpfs_node *node;
313
314 node = VP_TO_TMPFS_NODE(vp);
315 TMPFS_VALIDATE_DIR(node);
316 return node;
317 }
318 #else
319 # define VFS_TO_TMPFS(mp) ((struct tmpfs_mount *)mp->mnt_data)
320 # define VP_TO_TMPFS_NODE(vp) ((struct tmpfs_node *)vp->v_data)
321 # define VP_TO_TMPFS_DIR(vp) VP_TO_TMPFS_NODE(vp)
322 #endif
323
324 #endif /* _KERNEL */
325
326 /* ---------------------------------------------------------------------
327 * USER AND KERNEL DEFINITIONS
328 * --------------------------------------------------------------------- */
329
330 /*
331 * This structure is used to communicate mount parameters between userland
332 * and kernel space.
333 */
334 #define TMPFS_ARGS_VERSION 1
335 struct tmpfs_args {
336 int ta_version;
337
338 /* Size counters. */
339 ino_t ta_nodes_max;
340 off_t ta_size_max;
341
342 /* Root node attributes. */
343 uid_t ta_root_uid;
344 gid_t ta_root_gid;
345 mode_t ta_root_mode;
346 };
347