tmpfs.h revision 1.43 1 /* $NetBSD: tmpfs.h,v 1.43 2011/05/29 01:14:31 christos 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 /* The inode type: VBLK, VCHR, VDIR, VFIFO, VLNK, VREG or VSOCK. */
114 enum vtype tn_type;
115
116 /* Inode identifier. */
117 ino_t tn_id;
118
119 /* Inode status flags (for operations in delayed manner). */
120 int tn_status;
121
122 /* The inode size. */
123 off_t tn_size;
124
125 /* Generic node attributes. */
126 uid_t tn_uid;
127 gid_t tn_gid;
128 mode_t tn_mode;
129 int tn_flags;
130 nlink_t tn_links;
131 struct timespec tn_atime;
132 struct timespec tn_mtime;
133 struct timespec tn_ctime;
134 struct timespec tn_birthtime;
135 unsigned long tn_gen;
136
137 /* Head of byte-level lock list (used by tmpfs_advlock). */
138 struct lockf * tn_lockf;
139
140 /*
141 * Each inode has a corresponding vnode. It is a bi-directional
142 * association. Whenever vnode is allocated, its v_data field is
143 * set to the inode it reference, and tmpfs_node_t::tn_vnode is
144 * set to point to the said vnode.
145 *
146 * Further attempts to allocate a vnode for this same node will
147 * result in returning a new reference to the value stored in
148 * tn_vnode. It may be NULL when the node is unused (that is,
149 * no vnode has been allocated or it has been reclaimed).
150 */
151 kmutex_t tn_vlock;
152 vnode_t * tn_vnode;
153
154 union {
155 /* Type case: VBLK or VCHR. */
156 struct {
157 dev_t tn_rdev;
158 } tn_dev;
159
160 /* Type case: VDIR. */
161 struct {
162 /* Parent directory (root inode points to itself). */
163 struct tmpfs_node * tn_parent;
164
165 /* List of directory entries. */
166 struct tmpfs_dir tn_dir;
167
168 /*
169 * Number and pointer of the last directory entry
170 * returned by the readdir(3) operation.
171 */
172 off_t tn_readdir_lastn;
173 struct tmpfs_dirent * tn_readdir_lastp;
174 } tn_dir;
175
176 /* Type case: VLNK. */
177 struct tn_lnk {
178 /* The link's target. */
179 char * tn_link;
180 } tn_lnk;
181
182 /* Type case: VREG. */
183 struct tn_reg {
184 /* Underlying UVM object to store contents. */
185 struct uvm_object * tn_aobj;
186 size_t tn_aobj_pages;
187 } tn_reg;
188 } tn_spec;
189 } tmpfs_node_t;
190
191 #if defined(_KERNEL)
192
193 LIST_HEAD(tmpfs_node_list, tmpfs_node);
194
195 /* Status flags. */
196 #define TMPFS_NODE_ACCESSED 0x01
197 #define TMPFS_NODE_MODIFIED 0x02
198 #define TMPFS_NODE_CHANGED 0x04
199
200 #define TMPFS_NODE_STATUSALL \
201 (TMPFS_NODE_ACCESSED | TMPFS_NODE_MODIFIED | TMPFS_NODE_CHANGED)
202
203 /* White-out inode indicator. */
204 #define TMPFS_NODE_WHITEOUT ((tmpfs_node_t *)-1)
205
206 /*
207 * Internal representation of a tmpfs mount point.
208 */
209 typedef struct tmpfs_mount {
210 /* Limit and number of bytes in use by the file system. */
211 uint64_t tm_mem_limit;
212 uint64_t tm_bytes_used;
213 kmutex_t tm_acc_lock;
214
215 /* Pointer to the root inode. */
216 tmpfs_node_t * tm_root;
217
218 /* Maximum number of possible nodes for this file system. */
219 unsigned int tm_nodes_max;
220
221 /* Number of nodes currently allocated. */
222 unsigned int tm_nodes_cnt;
223
224 /* List of inodes and the lock protecting it. */
225 kmutex_t tm_lock;
226 struct tmpfs_node_list tm_nodes;
227 } tmpfs_mount_t;
228
229 /*
230 * This structure maps a file identifier to a tmpfs node. Used by the
231 * NFS code.
232 */
233 typedef struct tmpfs_fid {
234 uint16_t tf_len;
235 uint16_t tf_pad;
236 uint32_t tf_gen;
237 ino_t tf_id;
238 } tmpfs_fid_t;
239
240 /*
241 * Prototypes for tmpfs_subr.c.
242 */
243
244 int tmpfs_alloc_node(tmpfs_mount_t *, enum vtype, uid_t, gid_t,
245 mode_t, tmpfs_node_t *, char *, dev_t, tmpfs_node_t **);
246 void tmpfs_free_node(tmpfs_mount_t *, tmpfs_node_t *);
247
248 int tmpfs_alloc_file(vnode_t *, vnode_t **, struct vattr *,
249 struct componentname *, char *);
250
251 int tmpfs_alloc_vp(struct mount *, tmpfs_node_t *, vnode_t **);
252 void tmpfs_free_vp(vnode_t *);
253
254 int tmpfs_alloc_dirent(tmpfs_mount_t *, tmpfs_node_t *,
255 const char *, uint16_t, tmpfs_dirent_t **);
256 void tmpfs_free_dirent(tmpfs_mount_t *, tmpfs_dirent_t *, bool);
257 void tmpfs_dir_attach(vnode_t *, tmpfs_dirent_t *);
258 void tmpfs_dir_detach(vnode_t *, tmpfs_dirent_t *);
259
260 tmpfs_dirent_t *tmpfs_dir_lookup(tmpfs_node_t *, struct componentname *);
261 int tmpfs_dir_getdotdent(tmpfs_node_t *, struct uio *);
262 int tmpfs_dir_getdotdotdent(tmpfs_node_t *, struct uio *);
263 tmpfs_dirent_t *tmpfs_dir_lookupbycookie(tmpfs_node_t *, off_t);
264 int tmpfs_dir_getdents(tmpfs_node_t *, struct uio *, off_t *);
265
266 int tmpfs_reg_resize(vnode_t *, off_t);
267 int tmpfs_truncate(vnode_t *, off_t);
268
269 int tmpfs_chflags(vnode_t *, int, kauth_cred_t, lwp_t *);
270 int tmpfs_chmod(vnode_t *, mode_t, kauth_cred_t, lwp_t *);
271 int tmpfs_chown(vnode_t *, uid_t, gid_t, kauth_cred_t, lwp_t *);
272 int tmpfs_chsize(vnode_t *, u_quad_t, kauth_cred_t, lwp_t *);
273 int tmpfs_chtimes(vnode_t *, const struct timespec *,
274 const struct timespec *, const struct timespec *, int,
275 kauth_cred_t, lwp_t *);
276 void tmpfs_update(vnode_t *, const struct timespec *,
277 const struct timespec *, const struct timespec *, int);
278
279 /*
280 * Prototypes for tmpfs_mem.c.
281 */
282
283 void tmpfs_mntmem_init(tmpfs_mount_t *, uint64_t);
284 void tmpfs_mntmem_destroy(tmpfs_mount_t *);
285
286 size_t tmpfs_mem_info(bool);
287 uint64_t tmpfs_bytes_max(tmpfs_mount_t *);
288 size_t tmpfs_pages_avail(tmpfs_mount_t *);
289 bool tmpfs_mem_incr(tmpfs_mount_t *, size_t);
290 void tmpfs_mem_decr(tmpfs_mount_t *, size_t);
291
292 tmpfs_dirent_t *tmpfs_dirent_get(tmpfs_mount_t *);
293 void tmpfs_dirent_put(tmpfs_mount_t *, tmpfs_dirent_t *);
294
295 tmpfs_node_t * tmpfs_node_get(tmpfs_mount_t *);
296 void tmpfs_node_put(tmpfs_mount_t *, tmpfs_node_t *);
297
298 char * tmpfs_strname_alloc(tmpfs_mount_t *, size_t);
299 void tmpfs_strname_free(tmpfs_mount_t *, char *, size_t);
300 bool tmpfs_strname_neqlen(struct componentname *, struct componentname *);
301
302 /*
303 * Ensures that the node pointed by 'node' is a directory and that its
304 * contents are consistent with respect to directories.
305 */
306 #define TMPFS_VALIDATE_DIR(node) \
307 KASSERT((node)->tn_type == VDIR); \
308 KASSERT((node)->tn_size % sizeof(tmpfs_dirent_t) == 0); \
309 KASSERT((node)->tn_spec.tn_dir.tn_readdir_lastp == NULL || \
310 tmpfs_dircookie((node)->tn_spec.tn_dir.tn_readdir_lastp) == \
311 (node)->tn_spec.tn_dir.tn_readdir_lastn);
312
313 /*
314 * Memory management stuff.
315 */
316
317 /* Amount of memory pages to reserve for the system. */
318 #define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE)
319
320 /*
321 * Routines to convert VFS structures to tmpfs internal ones.
322 */
323
324 static inline tmpfs_mount_t *
325 VFS_TO_TMPFS(struct mount *mp)
326 {
327 tmpfs_mount_t *tmp = mp->mnt_data;
328
329 KASSERT(tmp != NULL);
330 return tmp;
331 }
332
333 static inline tmpfs_node_t *
334 VP_TO_TMPFS_DIR(vnode_t *vp)
335 {
336 tmpfs_node_t *node = vp->v_data;
337
338 KASSERT(node != NULL);
339 TMPFS_VALIDATE_DIR(node);
340 return node;
341 }
342
343 #endif /* defined(_KERNEL) */
344
345 static __inline tmpfs_node_t *
346 VP_TO_TMPFS_NODE(vnode_t *vp)
347 {
348 tmpfs_node_t *node = vp->v_data;
349 #ifdef KASSERT
350 KASSERT(node != NULL);
351 #endif
352 return node;
353 }
354
355 #endif /* _FS_TMPFS_TMPFS_H_ */
356