1 /* $NetBSD: tmpfs.h,v 1.26 2007/02/22 06:37:00 thorpej Exp $ */
4 * Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
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
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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.
32 * $FreeBSD: src/sys/fs/tmpfs/tmpfs.h,v 1.18 2009/10/11 07:03:56 delphij Exp $
35 #ifndef _VFS_TMPFS_TMPFS_H_
36 #define _VFS_TMPFS_TMPFS_H_
38 /* ---------------------------------------------------------------------
39 * KERNEL-SPECIFIC DEFINITIONS
40 * --------------------------------------------------------------------- */
41 #include <sys/dirent.h>
42 #include <sys/mount.h>
44 #include <sys/vnode.h>
47 #include <sys/lockf.h>
48 #include <sys/mutex.h>
49 #include <sys/objcache.h>
51 /* --------------------------------------------------------------------- */
52 #include <sys/malloc.h>
54 #include <sys/systm.h>
56 #include <sys/vmmeter.h>
57 #include <vm/swap_pager.h>
59 MALLOC_DECLARE(M_TMPFSMNT
);
61 /* --------------------------------------------------------------------- */
64 * Internal representation of a tmpfs directory entry.
67 RB_ENTRY(tmpfs_dirent
) rb_node
;
68 RB_ENTRY(tmpfs_dirent
) rb_cookienode
;
70 /* Length of the name stored in this directory entry. This avoids
71 * the need to recalculate it every time the name is used. */
74 /* The name of the entry, allocated from a string pool. This
75 * string is not required to be zero-terminated; therefore, the
76 * td_namelen field must always be used when accessing its value. */
79 /* Pointer to the node this entry refers to. */
80 struct tmpfs_node
*td_node
;
84 RB_HEAD(tmpfs_dirtree
, tmpfs_dirent
);
85 RB_PROTOTYPE(tmpfs_dirtree
, tmpfs_dirent
, rb_node
,
86 tmpfs_dirtree_compare
);
88 RB_HEAD(tmpfs_dirtree_cookie
, tmpfs_dirent
);
89 RB_PROTOTYPE(tmpfs_dirtree_cookie
, tmpfs_dirent
, rb_cookienode
,
90 tmpfs_dirtree_cookie_compare
);
94 * A directory in tmpfs holds a set of directory entries, which in
95 * turn point to other files (which can be directories themselves).
97 * In tmpfs, this set is managed by a red-black tree, whose root is defined
98 * by the struct tmpfs_dirtree type.
100 * It is important to notice that directories do not have entries for . and
101 * .. as other file systems do. These can be generated when requested
102 * based on information available by other means, such as the pointer to
103 * the node itself in the former case or the pointer to the parent directory
104 * in the latter case. This is done to simplify tmpfs's code and, more
105 * importantly, to remove redundancy.
107 * Each entry in a directory has a cookie that identifies it. Cookies
108 * supersede offsets within directories because, given how tmpfs stores
109 * directories in memory, there is no such thing as an offset. (Emulating
110 * a real offset could be very difficult.)
112 * The '.', '..' and the end of directory markers have fixed cookies which
113 * cannot collide with the cookies generated by other entries. The cookies
114 * for the other entries are generated based on the memory address on which
115 * stores their information is stored.
117 * DragonFly binaries use 64-bit cookies. We mask-off the signed bit to
118 * ensure that cookie 'offsets' are positive.
122 #define TMPFS_ROOTINO ((ino_t)2)
124 #define TMPFS_DIRCOOKIE_DOT 0
125 #define TMPFS_DIRCOOKIE_DOTDOT 1
126 #define TMPFS_DIRCOOKIE_EOF 2
130 tmpfs_dircookie(struct tmpfs_dirent
*de
)
132 return (((off_t
)(uintptr_t)de
>> 1) & 0x7FFFFFFFFFFFFFFFLLU
);
137 /* --------------------------------------------------------------------- */
140 * Internal representation of a tmpfs file system node.
142 * This structure is splitted in two parts: one holds attributes common
143 * to all file types and the other holds data that is only applicable to
144 * a particular type. The code must be careful to only access those
145 * attributes that are actually allowed by the node's type.
148 /* Doubly-linked list entry which links all existing nodes for a
149 * single file system. This is provided to ease the removal of
150 * all nodes during the unmount operation. */
151 LIST_ENTRY(tmpfs_node
) tn_entries
;
153 /* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO',
154 * 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode
155 * types instead of a custom enumeration is to make things simpler
156 * and faster, as we do not need to convert between two types. */
159 /* Node identifier. */
162 /* Node's internal status. This is used by several file system
163 * operations to do modifications to the node in a delayed
166 #define TMPFS_NODE_ACCESSED (1 << 1)
167 #define TMPFS_NODE_MODIFIED (1 << 2)
168 #define TMPFS_NODE_CHANGED (1 << 3)
170 /* The node size. It does not necessarily match the real amount
171 * of memory consumed by it. */
174 /* Generic node attributes. */
181 int32_t tn_atimensec
;
183 int32_t tn_mtimensec
;
185 int32_t tn_ctimensec
;
186 unsigned long tn_gen
;
187 struct lockf tn_advlock
;
189 /* As there is a single vnode for each active file within the
190 * system, care has to be taken to avoid allocating more than one
191 * vnode per file. In order to do this, a bidirectional association
192 * is kept between vnodes and nodes.
194 * Whenever a vnode is allocated, its v_data field is updated to
195 * point to the node it references. At the same time, the node's
196 * tn_vnode field is modified to point to the new vnode representing
197 * it. Further attempts to allocate a vnode for this same node will
198 * result in returning a new reference to the value stored in
201 * May be NULL when the node is unused (that is, no vnode has been
202 * allocated for it or it has been reclaimed). */
203 struct vnode
* tn_vnode
;
205 /* interlock to protect tn_vpstate */
206 struct lock tn_interlock
;
208 /* Identify if current node has vnode assiocate with
209 * or allocating vnode.
213 /* misc data field for different tn_type node */
215 /* Valid when tn_type == VBLK || tn_type == VCHR. */
216 dev_t tn_rdev
; /*int32_t ?*/
218 /* Valid when tn_type == VDIR. */
221 * Pointer to the parent directory. The root
222 * directory has a pointer to itself in this field;
223 * this property identifies the root node.
225 struct tmpfs_node
* tn_parent
;
228 * Directory entries are indexed by name and also
231 struct tmpfs_dirtree tn_dirtree
;
232 struct tmpfs_dirtree_cookie tn_cookietree
;
235 /* Valid when tn_type == VLNK. */
236 /* The link's target, allocated from a string pool. */
239 /* Valid when tn_type == VREG. */
241 /* The contents of regular files stored in a tmpfs
242 * file system are represented by a single anonymous
243 * memory object (aobj, for short). The aobj provides
244 * direct access to any position within the file,
245 * because its contents are always mapped in a
246 * contiguous region of virtual memory. It is a task
247 * of the memory management subsystem (see uvm(9)) to
248 * issue the required page ins or page outs whenever
249 * a position within the file is accessed. */
251 size_t tn_aobj_pages
;
255 /* Valid when tn_type = VFIFO */
257 int (*tn_fo_read
) (struct file
*fp
, struct uio
*uio
,
258 struct ucred
*cred
, int flags
);
259 int (*tn_fo_write
) (struct file
*fp
, struct uio
*uio
,
260 struct ucred
*cred
, int flags
);
265 /* Only userspace needs this */
266 #define VTOI(vp) ((struct tmpfs_node *)(vp)->v_data)
269 LIST_HEAD(tmpfs_node_list
, tmpfs_node
);
271 #define tn_rdev tn_spec.tn_rdev
272 #define tn_dir tn_spec.tn_dir
273 #define tn_link tn_spec.tn_link
274 #define tn_reg tn_spec.tn_reg
275 #define tn_fifo tn_spec.tn_fifo
277 #define TMPFS_NODE_LOCK(node) lockmgr(&(node)->tn_interlock, LK_EXCLUSIVE|LK_RETRY)
278 #define TMPFS_NODE_LOCK_SH(node) lockmgr(&(node)->tn_interlock, LK_SHARED|LK_RETRY)
279 #define TMPFS_NODE_UNLOCK(node) lockmgr(&(node)->tn_interlock, LK_RELEASE)
280 #define TMPFS_NODE_MTX(node) (&(node)->tn_interlock)
283 #define TMPFS_ASSERT_LOCKED(node) do { \
284 KKASSERT(node != NULL); \
285 KKASSERT(node->tn_vnode != NULL); \
286 if (!vn_islocked(node->tn_vnode) && \
287 (lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE )) \
288 panic("tmpfs: node is not locked: %p", node); \
290 #define TMPFS_ASSERT_ELOCKED(node) do { \
291 KKASSERT((node) != NULL); \
292 KKASSERT(lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE); \
295 #define TMPFS_ASSERT_LOCKED(node) (void)0
296 #define TMPFS_ASSERT_ELOCKED(node) (void)0
297 #endif /* INVARIANTS */
299 #define TMPFS_VNODE_ALLOCATING 1
300 #define TMPFS_VNODE_WANT 2
301 #define TMPFS_VNODE_DOOMED 4
302 /* --------------------------------------------------------------------- */
305 * Internal representation of a tmpfs mount point.
308 struct mount
*tm_mount
;
310 /* Maximum number of memory pages available for use by the file
311 * system, set during mount time. This variable must never be
312 * used directly as it may be bigger than the current amount of
313 * free memory; in the extreme case, it will hold the SIZE_MAX
314 * value. Instead, use the TMPFS_PAGES_MAX macro. */
317 /* Number of pages in use by the file system. Cannot be bigger
318 * than the value returned by TMPFS_PAGES_MAX in any case. */
321 /* Pointer to the node representing the root directory of this
323 struct tmpfs_node
* tm_root
;
325 /* Maximum number of possible nodes for this file system; set
326 * during mount time. We need a hard limit on the maximum number
327 * of nodes to avoid allocating too much of them; their objects
328 * cannot be released until the file system is unmounted.
329 * Otherwise, we could easily run out of memory by creating lots
330 * of empty files and then simply removing them. */
333 /* Number of nodes currently that are in use. */
334 ino_t tm_nodes_inuse
;
336 /* maximum representable file size */
337 u_int64_t tm_maxfilesize
;
339 /* Nodes are organized in two different lists. The used list
340 * contains all nodes that are currently used by the file system;
341 * i.e., they refer to existing files. The available list contains
342 * all nodes that are currently available for use by new files.
343 * Nodes must be kept in this list (instead of deleting them)
344 * because we need to keep track of their generation number (tn_gen
347 * Note that nodes are lazily allocated: if the available list is
348 * empty and we have enough space to create more nodes, they will be
349 * created and inserted in the used list. Once these are released,
350 * they will go into the available list, remaining alive until the
351 * file system is unmounted. */
352 struct tmpfs_node_list tm_nodes_used
;
354 /* Per-mount malloc zones for tmpfs nodes, names, and dirents */
355 struct malloc_type
*tm_node_zone
;
356 struct malloc_type
*tm_dirent_zone
;
357 struct malloc_type
*tm_name_zone
;
359 struct objcache_malloc_args tm_node_zone_malloc_args
;
360 struct objcache_malloc_args tm_dirent_zone_malloc_args
;
362 /* Pools used to store file system meta data. */
363 struct objcache
*tm_dirent_pool
;
364 struct objcache
*tm_node_pool
;
369 struct netexport tm_export
;
371 struct mount
*tm_mnt
;
374 #define TMPFS_LOCK(tm) lwkt_gettoken(&(tm)->tm_mount->mnt_token)
375 #define TMPFS_UNLOCK(tm) lwkt_reltoken(&(tm)->tm_mount->mnt_token)
377 /* --------------------------------------------------------------------- */
380 * This structure maps a file identifier to a tmpfs node. Used by the
387 unsigned long tf_gen
;
390 /* --------------------------------------------------------------------- */
393 * Prototypes for tmpfs_subr.c.
396 int tmpfs_alloc_node(struct tmpfs_mount
*, enum vtype
,
397 uid_t uid
, gid_t gid
, mode_t mode
, char *, int, int,
398 struct tmpfs_node
**);
399 void tmpfs_free_node(struct tmpfs_mount
*, struct tmpfs_node
*);
400 int tmpfs_alloc_dirent(struct tmpfs_mount
*, struct tmpfs_node
*,
401 const char *, uint16_t, struct tmpfs_dirent
**);
402 void tmpfs_free_dirent(struct tmpfs_mount
*, struct tmpfs_dirent
*);
403 int tmpfs_alloc_vp(struct mount
*, struct tmpfs_node
*, int,
405 void tmpfs_free_vp(struct vnode
*);
406 int tmpfs_alloc_file(struct vnode
*, struct vnode
**, struct vattr
*,
407 struct namecache
*, struct ucred
*, char *);
408 void tmpfs_dir_attach(struct tmpfs_node
*, struct tmpfs_dirent
*);
409 void tmpfs_dir_detach(struct tmpfs_node
*, struct tmpfs_dirent
*);
410 struct tmpfs_dirent
* tmpfs_dir_lookup(struct tmpfs_node
*node
,
411 struct tmpfs_node
*f
,
412 struct namecache
*ncp
);
413 int tmpfs_dir_getdotdent(struct tmpfs_node
*, struct uio
*);
414 int tmpfs_dir_getdotdotdent(struct tmpfs_mount
*,
415 struct tmpfs_node
*, struct uio
*);
416 struct tmpfs_dirent
* tmpfs_dir_lookupbycookie(struct tmpfs_node
*, off_t
);
417 int tmpfs_dir_getdents(struct tmpfs_node
*, struct uio
*, off_t
*);
418 int tmpfs_reg_resize(struct vnode
*, off_t
, int);
419 int tmpfs_chflags(struct vnode
*, int, struct ucred
*);
420 int tmpfs_chmod(struct vnode
*, mode_t
, struct ucred
*);
421 int tmpfs_chown(struct vnode
*, uid_t
, gid_t
, struct ucred
*);
422 int tmpfs_chsize(struct vnode
*, u_quad_t
, struct ucred
*);
423 int tmpfs_chtimes(struct vnode
*, struct timespec
*, struct timespec
*,
424 int, struct ucred
*);
425 void tmpfs_itimes(struct vnode
*, const struct timespec
*,
426 const struct timespec
*);
428 void tmpfs_update(struct vnode
*);
429 int tmpfs_truncate(struct vnode
*, off_t
);
430 boolean_t
tmpfs_node_ctor(void *obj
, void *privdata
, int flags
);
432 /* --------------------------------------------------------------------- */
435 * Convenience macros to simplify some logical expressions.
437 #define IMPLIES(a, b) (!(a) || (b))
438 #define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
440 /* --------------------------------------------------------------------- */
443 * Checks that the directory entry pointed by 'de' matches the name 'name'
444 * with a length of 'len'.
446 #define TMPFS_DIRENT_MATCHES(de, name, len) \
447 (de->td_namelen == (uint16_t)len && \
448 bcmp((de)->td_name, (name), (de)->td_namelen) == 0)
450 /* --------------------------------------------------------------------- */
453 * Ensures that the node pointed by 'node' is a directory and that its
454 * contents are consistent with respect to directories.
456 #define TMPFS_VALIDATE_DIR(node) do { \
457 KKASSERT((node)->tn_type == VDIR); \
458 KKASSERT((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \
461 /* --------------------------------------------------------------------- */
464 * Macros/functions to convert from generic data structures to tmpfs
465 * specific ones. Kernel code use VP_TO_TMPFS_NODE() instead of VTOI().
470 VFS_TO_TMPFS(struct mount
*mp
)
472 struct tmpfs_mount
*tmp
;
474 KKASSERT((mp
) != NULL
&& (mp
)->mnt_data
!= NULL
);
475 tmp
= (struct tmpfs_mount
*)(mp
)->mnt_data
;
481 VP_TO_TMPFS_NODE(struct vnode
*vp
)
483 struct tmpfs_node
*node
;
485 KKASSERT((vp
) != NULL
&& (vp
)->v_data
!= NULL
);
486 node
= (struct tmpfs_node
*)vp
->v_data
;
492 VP_TO_TMPFS_DIR(struct vnode
*vp
)
494 struct tmpfs_node
*node
;
496 node
= VP_TO_TMPFS_NODE(vp
);
497 TMPFS_VALIDATE_DIR(node
);
501 /* --------------------------------------------------------------------- */
505 #define TMPFS_BLKSIZE 16384 /* buffer cache size*/
506 #define TMPFS_BLKMASK (TMPFS_BLKSIZE - 1)
507 #define TMPFS_BLKMASK64 ((off_t)(TMPFS_BLKSIZE - 1))
510 #endif /* _VFS_TMPFS_TMPFS_H_ */