tmpfs.h revision 1.44 1 /* $NetBSD: tmpfs.h,v 1.44 2011/05/29 22:29:06 rmind Exp $ */
2
3 /*
4 * Copyright (c) 2005, 2006, 2007 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, developed as part of Google's Summer of Code
9 * 2005 program.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #ifndef _FS_TMPFS_TMPFS_H_
34 #define _FS_TMPFS_TMPFS_H_
35
36 #if !defined(_KERNEL) && !defined(_KMEMUSER)
37 #error "not supposed to be exposed to userland"
38 #endif
39
40 #include <sys/dirent.h>
41 #include <sys/mount.h>
42 #include <sys/pool.h>
43 #include <sys/queue.h>
44 #include <sys/vnode.h>
45
46 /*
47 * Internal representation of a tmpfs directory entry.
48 *
49 * All fields are protected by vnode lock.
50 */
51 typedef struct tmpfs_dirent {
52 TAILQ_ENTRY(tmpfs_dirent) td_entries;
53
54 /* Pointer to the inode this entry refers to. */
55 struct tmpfs_node * td_node;
56
57 /* Name and its length. */
58 char * td_name;
59 uint16_t td_namelen;
60 } tmpfs_dirent_t;
61
62 TAILQ_HEAD(tmpfs_dir, tmpfs_dirent);
63
64 #if defined(_KERNEL)
65
66 /* Validate maximum td_namelen length. */
67 CTASSERT(MAXNAMLEN < UINT16_MAX);
68
69 #define TMPFS_DIRCOOKIE_DOT 0
70 #define TMPFS_DIRCOOKIE_DOTDOT 1
71 #define TMPFS_DIRCOOKIE_EOF 2
72
73 /*
74 * Each entry in a directory has a cookie that identifies it. Cookies
75 * supersede offsets within directories, as tmpfs has no offsets as such.
76 *
77 * The '.', '..' and the end of directory markers have fixed cookies,
78 * which cannot collide with the cookies generated by other entries.
79 *
80 * The cookies for the other entries are generated based on the memory
81 * address of their representative meta-data structure.
82 *
83 * XXX: Truncating directory cookies to 31 bits now - workaround for
84 * problem with Linux compat, see PR/32034.
85 */
86 static inline off_t
87 tmpfs_dircookie(tmpfs_dirent_t *de)
88 {
89 off_t cookie;
90
91 cookie = ((off_t)(uintptr_t)de >> 1) & 0x7FFFFFFF;
92 KASSERT(cookie != TMPFS_DIRCOOKIE_DOT);
93 KASSERT(cookie != TMPFS_DIRCOOKIE_DOTDOT);
94 KASSERT(cookie != TMPFS_DIRCOOKIE_EOF);
95
96 return cookie;
97 }
98 #endif
99
100 /*
101 * Internal representation of a tmpfs file system node -- inode.
102 *
103 * This structure is splitted in two parts: one holds attributes common
104 * to all file types and the other holds data that is only applicable to
105 * a particular type.
106 *
107 * All fields are protected by vnode lock. The vnode association itself
108 * is protected by tmpfs_node_t::tn_vlock.
109 */
110 typedef struct tmpfs_node {
111 LIST_ENTRY(tmpfs_node) tn_entries;
112
113 /*
114 * Each inode has a corresponding vnode. It is a bi-directional
115 * association. Whenever vnode is allocated, its v_data field is
116 * set to the inode it reference, and tmpfs_node_t::tn_vnode is
117 * set to point to the said vnode.
118 *
119 * Further attempts to allocate a vnode for this same node will
120 * result in returning a new reference to the value stored in
121 * tn_vnode. It may be NULL when the node is unused (that is,
122 * no vnode has been allocated or it has been reclaimed).
123 */
124 kmutex_t tn_vlock;
125 vnode_t * tn_vnode;
126
127 /* Directory entry. Only a hint, since hard link can have multiple. */
128 tmpfs_dirent_t * tn_dirent_hint;
129
130 /* The inode type: VBLK, VCHR, VDIR, VFIFO, VLNK, VREG or VSOCK. */
131 enum vtype tn_type;
132
133 /* Inode identifier and generation number. */
134 ino_t tn_id;
135 unsigned long tn_gen;
136
137 /* Inode status flags (for operations in delayed manner). */
138 int tn_status;
139
140 /* The inode size. */
141 off_t tn_size;
142
143 /* Generic node attributes. */
144 uid_t tn_uid;
145 gid_t tn_gid;
146 mode_t tn_mode;
147 int tn_flags;
148 nlink_t tn_links;
149 struct timespec tn_atime;
150 struct timespec tn_mtime;
151 struct timespec tn_ctime;
152 struct timespec tn_birthtime;
153
154 /* Head of byte-level lock list (used by tmpfs_advlock). */
155 struct lockf * tn_lockf;
156
157 union {
158 /* Type case: VBLK or VCHR. */
159 struct {
160 dev_t tn_rdev;
161 } tn_dev;
162
163 /* Type case: VDIR. */
164 struct {
165 /* Parent directory (root inode points to itself). */
166 struct tmpfs_node * tn_parent;
167
168 /* List of directory entries. */
169 struct tmpfs_dir tn_dir;
170
171 /*
172 * Number and pointer of the last directory entry
173 * returned by the readdir(3) operation.
174 */
175 off_t tn_readdir_lastn;
176 struct tmpfs_dirent * tn_readdir_lastp;
177 } tn_dir;
178
179 /* Type case: VLNK. */
180 struct tn_lnk {
181 /* The link's target. */
182 char * tn_link;
183 } tn_lnk;
184
185 /* Type case: VREG. */
186 struct tn_reg {
187 /* Underlying UVM object to store contents. */
188 struct uvm_object * tn_aobj;
189 size_t tn_aobj_pages;
190 } tn_reg;
191 } tn_spec;
192 } tmpfs_node_t;
193
194 #if defined(_KERNEL)
195
196 LIST_HEAD(tmpfs_node_list, tmpfs_node);
197
198 /* Status flags. */
199 #define TMPFS_NODE_ACCESSED 0x01
200 #define TMPFS_NODE_MODIFIED 0x02
201 #define TMPFS_NODE_CHANGED 0x04
202
203 #define TMPFS_NODE_STATUSALL \
204 (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED)
205
206 /*
207 * Bit indicating vnode reclamation.
208 * We abuse tmpfs_node_t::tn_gen for that.
209 */
210 #define TMPFS_NODE_GEN_MASK (~0UL >> 1)
211 #define TMPFS_RECLAIMING_BIT (~TMPFS_NODE_GEN_MASK)
212
213 #define TMPFS_NODE_RECLAIMING(node) \
214 (((node)->tn_gen & TMPFS_RECLAIMING_BIT) != 0)
215
216 #define TMPFS_NODE_GEN(node) \
217 ((node)->tn_gen & TMPFS_NODE_GEN_MASK)
218
219 /* White-out inode indicator. */
220 #define TMPFS_NODE_WHITEOUT ((tmpfs_node_t *)-1)
221
222 /*
223 * Internal representation of a tmpfs mount point.
224 */
225 typedef struct tmpfs_mount {
226 /* Limit and number of bytes in use by the file system. */
227 uint64_t tm_mem_limit;
228 uint64_t tm_bytes_used;
229 kmutex_t tm_acc_lock;
230
231 /* Pointer to the root inode. */
232 tmpfs_node_t * tm_root;
233
234 /* Maximum number of possible nodes for this file system. */
235 unsigned int tm_nodes_max;
236
237 /* Number of nodes currently allocated. */
238 unsigned int tm_nodes_cnt;
239
240 /* List of inodes and the lock protecting it. */
241 kmutex_t tm_lock;
242 struct tmpfs_node_list tm_nodes;
243 } tmpfs_mount_t;
244
245 /*
246 * This structure maps a file identifier to a tmpfs node. Used by the
247 * NFS code.
248 */
249 typedef struct tmpfs_fid {
250 uint16_t tf_len;
251 uint16_t tf_pad;
252 uint32_t tf_gen;
253 ino_t tf_id;
254 } tmpfs_fid_t;
255
256 /*
257 * Prototypes for tmpfs_subr.c.
258 */
259
260 int tmpfs_alloc_node(tmpfs_mount_t *, enum vtype, uid_t, gid_t,
261 mode_t, char *, dev_t, tmpfs_node_t **);
262 void tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *);
263
264 int tmpfs_alloc_file(vnode_t *, vnode_t **, struct vattr *,
265 struct componentname *, char *);
266
267 int tmpfs_vnode_get(struct mount *, tmpfs_node_t *, vnode_t **);
268
269 int tmpfs_alloc_dirent(tmpfs_mount_t *, const char *, uint16_t,
270 tmpfs_dirent_t **);
271 void tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *);
272 void tmpfs_dir_attach(vnode_t *, tmpfs_dirent_t *, tmpfs_node_t *);
273 void tmpfs_dir_detach(vnode_t *, tmpfs_dirent_t *);
274
275 tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *);
276 tmpfs_dirent_t *tmpfs_dir_cached(tmpfs_node_t *);
277
278 int tmpfs_dir_getdotdent(tmpfs_node_t *, struct uio *);
279 int tmpfs_dir_getdotdotdent(tmpfs_node_t *, struct uio *);
280 tmpfs_dirent_t *tmpfs_dir_lookupbycookie(tmpfs_node_t *, off_t);
281 int tmpfs_dir_getdents(tmpfs_node_t *, struct uio *, off_t *);
282
283 int tmpfs_reg_resize(vnode_t *, off_t);
284 int tmpfs_truncate(vnode_t *, off_t);
285
286 int tmpfs_chflags(vnode_t *, int, kauth_cred_t, lwp_t *);
287 int tmpfs_chmod(vnode_t *, mode_t, kauth_cred_t, lwp_t *);
288 int tmpfs_chown(vnode_t *, uid_t, gid_t, kauth_cred_t, lwp_t *);
289 int tmpfs_chsize(vnode_t *, u_quad_t, kauth_cred_t, lwp_t *);
290 int tmpfs_chtimes(vnode_t *, const struct timespec *,
291 const struct timespec *, const struct timespec *, int,
292 kauth_cred_t, lwp_t *);
293 void tmpfs_update(vnode_t *, const struct timespec *,
294 const struct timespec *, const struct timespec *, int);
295
296 /*
297 * Prototypes for tmpfs_mem.c.
298 */
299
300 void tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t);
301 void tmpfs_mntmem_destroy(tmpfs_mount_t *);
302
303 size_t tmpfs_mem_info(bool);
304 uint64_t tmpfs_bytes_max(tmpfs_mount_t *);
305 size_t tmpfs_pages_avail(tmpfs_mount_t *);
306 bool tmpfs_mem_incr(tmpfs_mount_t *, size_t);
307 void tmpfs_mem_decr(tmpfs_mount_t *, size_t);
308
309 tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *);
310 void tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *);
311
312 tmpfs_node_t * tmpfs_node_get(tmpfs_mount_t *);
313 void tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *);
314
315 char * tmpfs_strname_alloc(tmpfs_mount_t *, size_t);
316 void tmpfs_strname_free(tmpfs_mount_t *, char *, size_t);
317 bool tmpfs_strname_neqlen(struct componentname *, struct componentname *);
318
319 /*
320 * Ensures that the node pointed by 'node' is a directory and that its
321 * contents are consistent with respect to directories.
322 */
323 #define TMPFS_VALIDATE_DIR(node) \
324 KASSERT((node)->tn_type == VDIR); \
325 KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0); \
326 KASSERT((node)->tn_spec.tn_dir.tn_readdir_lastp == NULL || \
327 tmpfs_dircookie((node)->tn_spec.tn_dir.tn_readdir_lastp) == \
328 (node)->tn_spec.tn_dir.tn_readdir_lastn);
329
330 /*
331 * Memory management stuff.
332 */
333
334 /* Amount of memory pages to reserve for the system. */
335 #define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE)
336
337 /*
338 * Routines to convert VFS structures to tmpfs internal ones.
339 */
340
341 static inline tmpfs_mount_t *
342 VFS_TO_TMPFS(struct mount *mp)
343 {
344 tmpfs_mount_t *tmp = mp->mnt_data;
345
346 KASSERT(tmp != NULL);
347 return tmp;
348 }
349
350 static inline tmpfs_node_t *
351 VP_TO_TMPFS_DIR(vnode_t *vp)
352 {
353 tmpfs_node_t *node = vp->v_data;
354
355 KASSERT(node != NULL);
356 TMPFS_VALIDATE_DIR(node);
357 return node;
358 }
359
360 #endif /* defined(_KERNEL) */
361
362 static __inline tmpfs_node_t *
363 VP_TO_TMPFS_NODE(vnode_t *vp)
364 {
365 tmpfs_node_t *node = vp->v_data;
366 #ifdef KASSERT
367 KASSERT(node != NULL);
368 #endif
369 return node;
370 }
371
372 #endif /* _FS_TMPFS_TMPFS_H_ */
373