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>
60 MALLOC_DECLARE(M_TMPFSMNT);
63 /* --------------------------------------------------------------------- */
66 * Internal representation of a tmpfs directory entry.
69 RB_ENTRY(tmpfs_dirent) rb_node;
70 RB_ENTRY(tmpfs_dirent) rb_cookienode;
72 /* Length of the name stored in this directory entry. This avoids
73 * the need to recalculate it every time the name is used. */
76 /* The name of the entry, allocated from a string pool. This
77 * string is not required to be zero-terminated; therefore, the
78 * td_namelen field must always be used when accessing its value. */
81 /* Pointer to the node this entry refers to. */
82 struct tmpfs_node *td_node;
86 RB_HEAD(tmpfs_dirtree, tmpfs_dirent);
87 RB_PROTOTYPE(tmpfs_dirtree, tmpfs_dirent, rb_node,
88 tmpfs_dirtree_compare);
90 RB_HEAD(tmpfs_dirtree_cookie, tmpfs_dirent);
91 RB_PROTOTYPE(tmpfs_dirtree_cookie, tmpfs_dirent, rb_cookienode,
92 tmpfs_dirtree_cookie_compare);
96 * A directory in tmpfs holds a set of directory entries, which in
97 * turn point to other files (which can be directories themselves).
99 * In tmpfs, this set is managed by a red-black tree, whose root is defined
100 * by the struct tmpfs_dirtree type.
102 * It is important to notice that directories do not have entries for . and
103 * .. as other file systems do. These can be generated when requested
104 * based on information available by other means, such as the pointer to
105 * the node itself in the former case or the pointer to the parent directory
106 * in the latter case. This is done to simplify tmpfs's code and, more
107 * importantly, to remove redundancy.
109 * Each entry in a directory has a cookie that identifies it. Cookies
110 * supersede offsets within directories because, given how tmpfs stores
111 * directories in memory, there is no such thing as an offset. (Emulating
112 * a real offset could be very difficult.)
114 * The '.', '..' and the end of directory markers have fixed cookies which
115 * cannot collide with the cookies generated by other entries. The cookies
116 * for the other entries are generated based on the memory address on which
117 * stores their information is stored.
119 * DragonFly binaries use 64-bit cookies. We mask-off the signed bit to
120 * ensure that cookie 'offsets' are positive.
124 #define TMPFS_ROOTINO ((ino_t)2)
126 #define TMPFS_DIRCOOKIE_DOT 0
127 #define TMPFS_DIRCOOKIE_DOTDOT 1
128 #define TMPFS_DIRCOOKIE_EOF 2
132 tmpfs_dircookie(struct tmpfs_dirent *de)
134 return (((off_t)(uintptr_t)de >> 1) & 0x7FFFFFFFFFFFFFFFLLU);
139 /* --------------------------------------------------------------------- */
142 * Internal representation of a tmpfs file system node.
144 * This structure is splitted in two parts: one holds attributes common
145 * to all file types and the other holds data that is only applicable to
146 * a particular type. The code must be careful to only access those
147 * attributes that are actually allowed by the node's type.
150 /* Doubly-linked list entry which links all existing nodes for a
151 * single file system. This is provided to ease the removal of
152 * all nodes during the unmount operation. */
153 LIST_ENTRY(tmpfs_node) tn_entries;
155 /* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO',
156 * 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode
157 * types instead of a custom enumeration is to make things simpler
158 * and faster, as we do not need to convert between two types. */
161 /* Node identifier. */
164 /* Node's internal status. This is used by several file system
165 * operations to do modifications to the node in a delayed
167 int tn_blksize; /* small file optimization */
169 #define TMPFS_NODE_ACCESSED (1 << 1)
170 #define TMPFS_NODE_MODIFIED (1 << 2)
171 #define TMPFS_NODE_CHANGED (1 << 3)
173 /* The node size. It does not necessarily match the real amount
174 * of memory consumed by it. */
177 /* Generic node attributes. */
182 nlink_t tn_links; /* atomic ops req */
189 unsigned long tn_gen;
190 struct lockf tn_advlock;
192 /* As there is a single vnode for each active file within the
193 * system, care has to be taken to avoid allocating more than one
194 * vnode per file. In order to do this, a bidirectional association
195 * is kept between vnodes and nodes.
197 * Whenever a vnode is allocated, its v_data field is updated to
198 * point to the node it references. At the same time, the node's
199 * tn_vnode field is modified to point to the new vnode representing
200 * it. Further attempts to allocate a vnode for this same node will
201 * result in returning a new reference to the value stored in
204 * May be NULL when the node is unused (that is, no vnode has been
205 * allocated for it or it has been reclaimed). */
206 struct vnode * tn_vnode;
208 /* interlock to protect structure */
209 struct lock tn_interlock;
212 * tmpfs vnode state, may specify an allocation in-progress.
216 /* misc data field for different tn_type node */
218 /* Valid when tn_type == VBLK || tn_type == VCHR. */
219 dev_t tn_rdev; /*int32_t ?*/
221 /* Valid when tn_type == VDIR. */
224 * Pointer to the parent directory. The root
225 * directory has a pointer to itself in this field;
226 * this property identifies the root node.
228 struct tmpfs_node * tn_parent;
231 * Directory entries are indexed by name and also
234 struct tmpfs_dirtree tn_dirtree;
235 struct tmpfs_dirtree_cookie tn_cookietree;
238 /* Valid when tn_type == VLNK. */
239 /* The link's target, allocated from a string pool. */
243 * Valid when tn_type == VREG.
245 * aobj is used as backing store for the vnode object. It
246 * typically only contains swap assignments, but we also use
247 * it to save the vnode object's vm_page's when the vnode
252 size_t tn_aobj_pages;
253 int tn_pages_in_aobj;
256 /* Valid when tn_type = VFIFO */
258 int (*tn_fo_read) (struct file *fp, struct uio *uio,
259 struct ucred *cred, int flags);
260 int (*tn_fo_write) (struct file *fp, struct uio *uio,
261 struct ucred *cred, int flags);
266 /* Only userspace needs this */
267 #define VTOI(vp) ((struct tmpfs_node *)(vp)->v_data)
270 LIST_HEAD(tmpfs_node_list, tmpfs_node);
272 #define tn_rdev tn_spec.tn_rdev
273 #define tn_dir tn_spec.tn_dir
274 #define tn_link tn_spec.tn_link
275 #define tn_reg tn_spec.tn_reg
276 #define tn_fifo tn_spec.tn_fifo
278 #define TMPFS_NODE_LOCK(node) lockmgr(&(node)->tn_interlock, LK_EXCLUSIVE|LK_RETRY)
279 #define TMPFS_NODE_LOCK_SH(node) lockmgr(&(node)->tn_interlock, LK_SHARED|LK_RETRY)
280 #define TMPFS_NODE_UNLOCK(node) lockmgr(&(node)->tn_interlock, LK_RELEASE)
281 #define TMPFS_NODE_MTX(node) (&(node)->tn_interlock)
284 #define TMPFS_ASSERT_LOCKED(node) do { \
285 KKASSERT(node != NULL); \
286 KKASSERT(node->tn_vnode != NULL); \
287 if (!vn_islocked(node->tn_vnode) && \
288 (lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE )) \
289 panic("tmpfs: node is not locked: %p", node); \
291 #define TMPFS_ASSERT_ELOCKED(node) do { \
292 KKASSERT((node) != NULL); \
293 KKASSERT(lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE); \
296 #define TMPFS_ASSERT_LOCKED(node) (void)0
297 #define TMPFS_ASSERT_ELOCKED(node) (void)0
298 #endif /* INVARIANTS */
300 #define TMPFS_VNODE_DOOMED 0x0001
301 /* --------------------------------------------------------------------- */
304 * Internal representation of a tmpfs mount point.
307 struct mount *tm_mount;
309 /* Maximum number of memory pages available for use by the file
310 * system, set during mount time. This variable must never be
311 * used directly as it may be bigger than the current amount of
312 * free memory; in the extreme case, it will hold the SIZE_MAX
313 * value. Instead, use the TMPFS_PAGES_MAX macro. */
316 /* Number of pages in use by the file system. Cannot be bigger
317 * than the value returned by TMPFS_PAGES_MAX in any case. */
320 /* Pointer to the node representing the root directory of this
322 struct tmpfs_node * tm_root;
324 /* Maximum number of possible nodes for this file system; set
325 * during mount time. We need a hard limit on the maximum number
326 * of nodes to avoid allocating too much of them; their objects
327 * cannot be released until the file system is unmounted.
328 * Otherwise, we could easily run out of memory by creating lots
329 * of empty files and then simply removing them. */
332 /* Number of nodes currently that are in use. */
333 ino_t tm_nodes_inuse;
335 /* maximum representable file size */
336 u_int64_t tm_maxfilesize;
338 /* Nodes are organized in two different lists. The used list
339 * contains all nodes that are currently used by the file system;
340 * i.e., they refer to existing files. The available list contains
341 * all nodes that are currently available for use by new files.
342 * Nodes must be kept in this list (instead of deleting them)
343 * because we need to keep track of their generation number (tn_gen
346 * Note that nodes are lazily allocated: if the available list is
347 * empty and we have enough space to create more nodes, they will be
348 * created and inserted in the used list. Once these are released,
349 * they will go into the available list, remaining alive until the
350 * file system is unmounted. */
351 struct tmpfs_node_list tm_nodes_used;
353 /* Per-mount malloc zones for tmpfs nodes, names, and dirents */
354 struct malloc_type *tm_node_zone;
355 struct malloc_type *tm_dirent_zone;
356 struct malloc_type *tm_name_zone;
358 struct objcache_malloc_args tm_node_zone_malloc_args;
359 struct objcache_malloc_args tm_dirent_zone_malloc_args;
361 /* Pools used to store file system meta data. */
362 struct objcache *tm_dirent_pool;
363 struct objcache *tm_node_pool;
368 struct netexport tm_export;
370 struct mount *tm_mnt;
373 #define TMPFS_LOCK(tm) lwkt_gettoken(&(tm)->tm_mount->mnt_token)
374 #define TMPFS_UNLOCK(tm) lwkt_reltoken(&(tm)->tm_mount->mnt_token)
376 /* --------------------------------------------------------------------- */
379 * This structure maps a file identifier to a tmpfs node. Used by the
386 unsigned long tf_gen;
389 /* --------------------------------------------------------------------- */
392 * Prototypes for tmpfs_subr.c.
395 int tmpfs_alloc_node(struct tmpfs_mount *, enum vtype,
396 uid_t uid, gid_t gid, mode_t mode, char *, int, int,
397 struct tmpfs_node **);
398 void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *);
399 int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *,
400 const char *, uint16_t, struct tmpfs_dirent **);
401 void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *);
402 int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *,
403 struct tmpfs_node *, int, struct vnode **);
404 int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *,
405 struct namecache *, struct ucred *, char *);
406 void tmpfs_dir_attach_locked(struct tmpfs_node *, struct tmpfs_dirent *);
407 void tmpfs_dir_detach_locked(struct tmpfs_node *, struct tmpfs_dirent *);
408 struct tmpfs_dirent * tmpfs_dir_lookup(struct tmpfs_node *node,
409 struct tmpfs_node *f,
410 struct namecache *ncp);
411 int tmpfs_dir_getdotdent(struct tmpfs_node *, struct uio *);
412 int tmpfs_dir_getdotdotdent(struct tmpfs_mount *,
413 struct tmpfs_node *, struct uio *);
414 struct tmpfs_dirent * tmpfs_dir_lookupbycookie(struct tmpfs_node *, off_t);
415 int tmpfs_dir_getdents(struct tmpfs_node *, struct uio *, off_t *);
416 int tmpfs_reg_resize(struct vnode *, off_t, int);
417 int tmpfs_chflags(struct vnode *, u_long, struct ucred *);
418 int tmpfs_chmod(struct vnode *, mode_t, struct ucred *);
419 int tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *);
420 int tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *);
421 int tmpfs_chtimes(struct vnode *, struct timespec *, struct timespec *,
422 int, struct ucred *);
423 void tmpfs_itimes(struct vnode *, const struct timespec *,
424 const struct timespec *);
426 void tmpfs_update(struct vnode *);
427 int tmpfs_truncate(struct vnode *, off_t);
428 boolean_t tmpfs_node_ctor(void *obj, void *privdata, int flags);
429 void tmpfs_lock4(struct tmpfs_node *node1, struct tmpfs_node *node2,
430 struct tmpfs_node *node3, struct tmpfs_node *node4);
431 void tmpfs_unlock4(struct tmpfs_node *node1, struct tmpfs_node *node2,
432 struct tmpfs_node *node3, struct tmpfs_node *node4);
434 /* --------------------------------------------------------------------- */
437 * Convenience macros to simplify some logical expressions.
439 #define IMPLIES(a, b) (!(a) || (b))
440 #define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a))
442 /* --------------------------------------------------------------------- */
445 * Checks that the directory entry pointed by 'de' matches the name 'name'
446 * with a length of 'len'.
448 #define TMPFS_DIRENT_MATCHES(de, name, len) \
449 (de->td_namelen == (uint16_t)len && \
450 bcmp((de)->td_name, (name), (de)->td_namelen) == 0)
452 /* --------------------------------------------------------------------- */
455 * Ensures that the node pointed by 'node' is a directory and that its
456 * contents are consistent with respect to directories.
458 #define TMPFS_VALIDATE_DIR(node) do { \
459 KKASSERT((node)->tn_type == VDIR); \
460 KKASSERT((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \
463 /* --------------------------------------------------------------------- */
466 * Macros/functions to convert from generic data structures to tmpfs
467 * specific ones. Kernel code use VP_TO_TMPFS_NODE() instead of VTOI().
472 VFS_TO_TMPFS(struct mount *mp)
474 struct tmpfs_mount *tmp;
476 KKASSERT((mp) != NULL && (mp)->mnt_data != NULL);
477 tmp = (struct tmpfs_mount *)(mp)->mnt_data;
483 VP_TO_TMPFS_NODE(struct vnode *vp)
485 struct tmpfs_node *node;
487 KKASSERT((vp) != NULL && (vp)->v_data != NULL);
488 node = (struct tmpfs_node *)vp->v_data;
494 VP_TO_TMPFS_DIR(struct vnode *vp)
496 struct tmpfs_node *node;
498 node = VP_TO_TMPFS_NODE(vp);
499 TMPFS_VALIDATE_DIR(node);
503 /* --------------------------------------------------------------------- */
507 #define TMPFS_BLKSIZE 16384 /* buffer cache size*/
508 #define TMPFS_BLKMASK (TMPFS_BLKSIZE - 1)
509 #define TMPFS_BLKMASK64 ((off_t)(TMPFS_BLKSIZE - 1))
512 #endif /* _VFS_TMPFS_TMPFS_H_ */