1 /* $NetBSD: tmpfs.h,v 1.26 2007/02/22 06:37:00 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2005, 2006 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 * $FreeBSD: src/sys/fs/tmpfs/tmpfs.h,v 1.18 2009/10/11 07:03:56 delphij Exp $ 33 */ 34 35 #ifndef _VFS_TMPFS_TMPFS_H_ 36 #define _VFS_TMPFS_TMPFS_H_ 37 38 /* --------------------------------------------------------------------- 39 * KERNEL-SPECIFIC DEFINITIONS 40 * --------------------------------------------------------------------- */ 41 #include <sys/dirent.h> 42 #include <sys/mount.h> 43 #include <sys/tree.h> 44 #include <sys/vnode.h> 45 #include <sys/file.h> 46 #include <sys/lock.h> 47 #include <sys/lockf.h> 48 #include <sys/mutex.h> 49 #include <sys/objcache.h> 50 51 /* --------------------------------------------------------------------- */ 52 #include <sys/malloc.h> 53 #ifdef _KERNEL 54 #include <sys/systm.h> 55 #endif 56 #include <sys/vmmeter.h> 57 #include <vm/swap_pager.h> 58 59 MALLOC_DECLARE(M_TMPFSMNT); 60 61 /* --------------------------------------------------------------------- */ 62 63 /* 64 * Internal representation of a tmpfs directory entry. 65 */ 66 struct tmpfs_dirent { 67 RB_ENTRY(tmpfs_dirent) rb_node; 68 RB_ENTRY(tmpfs_dirent) rb_cookienode; 69 70 /* Length of the name stored in this directory entry. This avoids 71 * the need to recalculate it every time the name is used. */ 72 uint16_t td_namelen; 73 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. */ 77 char *td_name; 78 79 /* Pointer to the node this entry refers to. */ 80 struct tmpfs_node *td_node; 81 }; 82 83 struct tmpfs_dirtree; 84 RB_HEAD(tmpfs_dirtree, tmpfs_dirent); 85 RB_PROTOTYPE(tmpfs_dirtree, tmpfs_dirent, rb_node, 86 tmpfs_dirtree_compare); 87 88 RB_HEAD(tmpfs_dirtree_cookie, tmpfs_dirent); 89 RB_PROTOTYPE(tmpfs_dirtree_cookie, tmpfs_dirent, rb_cookienode, 90 tmpfs_dirtree_cookie_compare); 91 92 93 /* 94 * A directory in tmpfs holds a set of directory entries, which in 95 * turn point to other files (which can be directories themselves). 96 * 97 * In tmpfs, this set is managed by a red-black tree, whose root is defined 98 * by the struct tmpfs_dirtree type. 99 * 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. 106 * 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.) 111 * 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. 116 * 117 * DragonFly binaries use 64-bit cookies. We mask-off the signed bit to 118 * ensure that cookie 'offsets' are positive. 119 */ 120 #ifdef _KERNEL 121 122 #define TMPFS_ROOTINO ((ino_t)2) 123 124 #define TMPFS_DIRCOOKIE_DOT 0 125 #define TMPFS_DIRCOOKIE_DOTDOT 1 126 #define TMPFS_DIRCOOKIE_EOF 2 127 128 static __inline 129 off_t 130 tmpfs_dircookie(struct tmpfs_dirent *de) 131 { 132 return (((off_t)(uintptr_t)de >> 1) & 0x7FFFFFFFFFFFFFFFLLU); 133 } 134 135 #endif /* _KERNEL */ 136 137 /* --------------------------------------------------------------------- */ 138 139 /* 140 * Internal representation of a tmpfs file system node. 141 * 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. 146 */ 147 struct tmpfs_node { 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; 152 153 /* 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. */ 157 enum vtype tn_type; 158 159 /* Node identifier. */ 160 ino_t tn_id; 161 162 /* Node's internal status. This is used by several file system 163 * operations to do modifications to the node in a delayed 164 * fashion. */ 165 int tn_status; 166 #define TMPFS_NODE_ACCESSED (1 << 1) 167 #define TMPFS_NODE_MODIFIED (1 << 2) 168 #define TMPFS_NODE_CHANGED (1 << 3) 169 170 /* The node size. It does not necessarily match the real amount 171 * of memory consumed by it. */ 172 off_t tn_size; 173 174 /* Generic node attributes. */ 175 uid_t tn_uid; 176 gid_t tn_gid; 177 mode_t tn_mode; 178 int tn_flags; 179 nlink_t tn_links; 180 long tn_atime; 181 long tn_atimensec; 182 long tn_mtime; 183 long tn_mtimensec; 184 long tn_ctime; 185 long tn_ctimensec; 186 unsigned long tn_gen; 187 struct lockf tn_advlock; 188 189 /* 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. 193 * 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 199 * tn_vnode. 200 * 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; 204 205 /* interlock to protect tn_vpstate */ 206 struct lock tn_interlock; 207 208 /* Identify if current node has vnode assiocate with 209 * or allocating vnode. 210 */ 211 int tn_vpstate; 212 213 /* misc data field for different tn_type node */ 214 union { 215 /* Valid when tn_type == VBLK || tn_type == VCHR. */ 216 dev_t tn_rdev; /*int32_t ?*/ 217 218 /* Valid when tn_type == VDIR. */ 219 struct tn_dir { 220 /* 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. 224 */ 225 struct tmpfs_node * tn_parent; 226 227 /* 228 * Directory entries are indexed by name and also 229 * indexed by cookie. 230 */ 231 struct tmpfs_dirtree tn_dirtree; 232 struct tmpfs_dirtree_cookie tn_cookietree; 233 } tn_dir; 234 235 /* Valid when tn_type == VLNK. */ 236 /* The link's target, allocated from a string pool. */ 237 char * tn_link; 238 239 /* 240 * Valid when tn_type == VREG. 241 * 242 * aobj is used as backing store for the vnode object. It 243 * typically only contains swap assignments, but we also use 244 * it to save the vnode object's vm_page's when the vnode 245 * becomes inactive. 246 */ 247 struct tn_reg { 248 vm_object_t tn_aobj; 249 size_t tn_aobj_pages; 250 int tn_pages_in_aobj; 251 } tn_reg; 252 253 /* Valid when tn_type = VFIFO */ 254 struct tn_fifo { 255 int (*tn_fo_read) (struct file *fp, struct uio *uio, 256 struct ucred *cred, int flags); 257 int (*tn_fo_write) (struct file *fp, struct uio *uio, 258 struct ucred *cred, int flags); 259 } tn_fifo; 260 } tn_spec; 261 }; 262 263 /* Only userspace needs this */ 264 #define VTOI(vp) ((struct tmpfs_node *)(vp)->v_data) 265 266 #ifdef _KERNEL 267 LIST_HEAD(tmpfs_node_list, tmpfs_node); 268 269 #define tn_rdev tn_spec.tn_rdev 270 #define tn_dir tn_spec.tn_dir 271 #define tn_link tn_spec.tn_link 272 #define tn_reg tn_spec.tn_reg 273 #define tn_fifo tn_spec.tn_fifo 274 275 #define TMPFS_NODE_LOCK(node) lockmgr(&(node)->tn_interlock, LK_EXCLUSIVE|LK_RETRY) 276 #define TMPFS_NODE_LOCK_SH(node) lockmgr(&(node)->tn_interlock, LK_SHARED|LK_RETRY) 277 #define TMPFS_NODE_UNLOCK(node) lockmgr(&(node)->tn_interlock, LK_RELEASE) 278 #define TMPFS_NODE_MTX(node) (&(node)->tn_interlock) 279 280 #ifdef INVARIANTS 281 #define TMPFS_ASSERT_LOCKED(node) do { \ 282 KKASSERT(node != NULL); \ 283 KKASSERT(node->tn_vnode != NULL); \ 284 if (!vn_islocked(node->tn_vnode) && \ 285 (lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE )) \ 286 panic("tmpfs: node is not locked: %p", node); \ 287 } while (0) 288 #define TMPFS_ASSERT_ELOCKED(node) do { \ 289 KKASSERT((node) != NULL); \ 290 KKASSERT(lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE); \ 291 } while (0) 292 #else 293 #define TMPFS_ASSERT_LOCKED(node) (void)0 294 #define TMPFS_ASSERT_ELOCKED(node) (void)0 295 #endif /* INVARIANTS */ 296 297 #define TMPFS_VNODE_ALLOCATING 1 298 #define TMPFS_VNODE_WANT 2 299 #define TMPFS_VNODE_DOOMED 4 300 /* --------------------------------------------------------------------- */ 301 302 /* 303 * Internal representation of a tmpfs mount point. 304 */ 305 struct tmpfs_mount { 306 struct mount *tm_mount; 307 308 /* Maximum number of memory pages available for use by the file 309 * system, set during mount time. This variable must never be 310 * used directly as it may be bigger than the current amount of 311 * free memory; in the extreme case, it will hold the SIZE_MAX 312 * value. Instead, use the TMPFS_PAGES_MAX macro. */ 313 long tm_pages_max; 314 315 /* Number of pages in use by the file system. Cannot be bigger 316 * than the value returned by TMPFS_PAGES_MAX in any case. */ 317 long tm_pages_used; 318 319 /* Pointer to the node representing the root directory of this 320 * file system. */ 321 struct tmpfs_node * tm_root; 322 323 /* Maximum number of possible nodes for this file system; set 324 * during mount time. We need a hard limit on the maximum number 325 * of nodes to avoid allocating too much of them; their objects 326 * cannot be released until the file system is unmounted. 327 * Otherwise, we could easily run out of memory by creating lots 328 * of empty files and then simply removing them. */ 329 ino_t tm_nodes_max; 330 331 /* Number of nodes currently that are in use. */ 332 ino_t tm_nodes_inuse; 333 334 /* maximum representable file size */ 335 u_int64_t tm_maxfilesize; 336 337 /* Nodes are organized in two different lists. The used list 338 * contains all nodes that are currently used by the file system; 339 * i.e., they refer to existing files. The available list contains 340 * all nodes that are currently available for use by new files. 341 * Nodes must be kept in this list (instead of deleting them) 342 * because we need to keep track of their generation number (tn_gen 343 * field). 344 * 345 * Note that nodes are lazily allocated: if the available list is 346 * empty and we have enough space to create more nodes, they will be 347 * created and inserted in the used list. Once these are released, 348 * they will go into the available list, remaining alive until the 349 * file system is unmounted. */ 350 struct tmpfs_node_list tm_nodes_used; 351 352 /* Per-mount malloc zones for tmpfs nodes, names, and dirents */ 353 struct malloc_type *tm_node_zone; 354 struct malloc_type *tm_dirent_zone; 355 struct malloc_type *tm_name_zone; 356 357 struct objcache_malloc_args tm_node_zone_malloc_args; 358 struct objcache_malloc_args tm_dirent_zone_malloc_args; 359 360 /* Pools used to store file system meta data. */ 361 struct objcache *tm_dirent_pool; 362 struct objcache *tm_node_pool; 363 364 ino_t tm_ino; 365 int tm_flags; 366 367 struct netexport tm_export; 368 369 struct mount *tm_mnt; 370 }; 371 372 #define TMPFS_LOCK(tm) lwkt_gettoken(&(tm)->tm_mount->mnt_token) 373 #define TMPFS_UNLOCK(tm) lwkt_reltoken(&(tm)->tm_mount->mnt_token) 374 375 /* --------------------------------------------------------------------- */ 376 377 /* 378 * This structure maps a file identifier to a tmpfs node. Used by the 379 * NFS code. 380 */ 381 struct tmpfs_fid { 382 uint16_t tf_len; 383 uint16_t tf_pad; 384 ino_t tf_id; 385 unsigned long tf_gen; 386 } __packed; 387 388 /* --------------------------------------------------------------------- */ 389 390 /* 391 * Prototypes for tmpfs_subr.c. 392 */ 393 394 int tmpfs_alloc_node(struct tmpfs_mount *, enum vtype, 395 uid_t uid, gid_t gid, mode_t mode, char *, int, int, 396 struct tmpfs_node **); 397 void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *); 398 int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *, 399 const char *, uint16_t, struct tmpfs_dirent **); 400 void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *); 401 int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, 402 struct tmpfs_node *, int, struct vnode **); 403 void tmpfs_free_vp(struct vnode *); 404 int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *, 405 struct namecache *, struct ucred *, char *); 406 void tmpfs_dir_attach(struct tmpfs_node *, struct tmpfs_dirent *); 407 void tmpfs_dir_detach(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 *, int, 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 *); 425 426 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); 429 430 /* --------------------------------------------------------------------- */ 431 432 /* 433 * Convenience macros to simplify some logical expressions. 434 */ 435 #define IMPLIES(a, b) (!(a) || (b)) 436 #define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a)) 437 438 /* --------------------------------------------------------------------- */ 439 440 /* 441 * Checks that the directory entry pointed by 'de' matches the name 'name' 442 * with a length of 'len'. 443 */ 444 #define TMPFS_DIRENT_MATCHES(de, name, len) \ 445 (de->td_namelen == (uint16_t)len && \ 446 bcmp((de)->td_name, (name), (de)->td_namelen) == 0) 447 448 /* --------------------------------------------------------------------- */ 449 450 /* 451 * Ensures that the node pointed by 'node' is a directory and that its 452 * contents are consistent with respect to directories. 453 */ 454 #define TMPFS_VALIDATE_DIR(node) do { \ 455 KKASSERT((node)->tn_type == VDIR); \ 456 KKASSERT((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \ 457 } while(0) 458 459 /* --------------------------------------------------------------------- */ 460 461 /* 462 * Macros/functions to convert from generic data structures to tmpfs 463 * specific ones. Kernel code use VP_TO_TMPFS_NODE() instead of VTOI(). 464 */ 465 466 static inline 467 struct tmpfs_mount * 468 VFS_TO_TMPFS(struct mount *mp) 469 { 470 struct tmpfs_mount *tmp; 471 472 KKASSERT((mp) != NULL && (mp)->mnt_data != NULL); 473 tmp = (struct tmpfs_mount *)(mp)->mnt_data; 474 return tmp; 475 } 476 477 static inline 478 struct tmpfs_node * 479 VP_TO_TMPFS_NODE(struct vnode *vp) 480 { 481 struct tmpfs_node *node; 482 483 KKASSERT((vp) != NULL && (vp)->v_data != NULL); 484 node = (struct tmpfs_node *)vp->v_data; 485 return node; 486 } 487 488 static inline 489 struct tmpfs_node * 490 VP_TO_TMPFS_DIR(struct vnode *vp) 491 { 492 struct tmpfs_node *node; 493 494 node = VP_TO_TMPFS_NODE(vp); 495 TMPFS_VALIDATE_DIR(node); 496 return node; 497 } 498 499 /* --------------------------------------------------------------------- */ 500 /* 501 * buffer cache size 502 */ 503 #define TMPFS_BLKSIZE 16384 /* buffer cache size*/ 504 #define TMPFS_BLKMASK (TMPFS_BLKSIZE - 1) 505 #define TMPFS_BLKMASK64 ((off_t)(TMPFS_BLKSIZE - 1)) 506 #endif /* _KERNEL */ 507 508 #endif /* _VFS_TMPFS_TMPFS_H_ */ 509