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 50 /* --------------------------------------------------------------------- */ 51 #include <sys/malloc.h> 52 #ifdef _KERNEL 53 #include <sys/systm.h> 54 #endif 55 #include <sys/vmmeter.h> 56 #include <vm/swap_pager.h> 57 58 #ifdef MALLOC_DECLARE 59 MALLOC_DECLARE(M_TMPFSMNT); 60 #endif 61 62 /* --------------------------------------------------------------------- */ 63 64 /* 65 * Internal representation of a tmpfs directory entry. 66 */ 67 struct tmpfs_dirent { 68 RB_ENTRY(tmpfs_dirent) rb_node; 69 RB_ENTRY(tmpfs_dirent) rb_cookienode; 70 71 /* Length of the name stored in this directory entry. This avoids 72 * the need to recalculate it every time the name is used. */ 73 uint16_t td_namelen; 74 75 /* The name of the entry, allocated from a string pool. This 76 * string is not required to be zero-terminated; therefore, the 77 * td_namelen field must always be used when accessing its value. */ 78 char *td_name; 79 80 /* Pointer to the node this entry refers to. */ 81 struct tmpfs_node *td_node; 82 }; 83 84 struct tmpfs_dirtree; 85 RB_HEAD(tmpfs_dirtree, tmpfs_dirent); 86 RB_PROTOTYPE(tmpfs_dirtree, tmpfs_dirent, rb_node, 87 tmpfs_dirtree_compare); 88 89 RB_HEAD(tmpfs_dirtree_cookie, tmpfs_dirent); 90 RB_PROTOTYPE(tmpfs_dirtree_cookie, tmpfs_dirent, rb_cookienode, 91 tmpfs_dirtree_cookie_compare); 92 93 94 /* 95 * A directory in tmpfs holds a set of directory entries, which in 96 * turn point to other files (which can be directories themselves). 97 * 98 * In tmpfs, this set is managed by a red-black tree, whose root is defined 99 * by the struct tmpfs_dirtree type. 100 * 101 * It is important to notice that directories do not have entries for . and 102 * .. as other file systems do. These can be generated when requested 103 * based on information available by other means, such as the pointer to 104 * the node itself in the former case or the pointer to the parent directory 105 * in the latter case. This is done to simplify tmpfs's code and, more 106 * importantly, to remove redundancy. 107 * 108 * Each entry in a directory has a cookie that identifies it. Cookies 109 * supersede offsets within directories because, given how tmpfs stores 110 * directories in memory, there is no such thing as an offset. (Emulating 111 * a real offset could be very difficult.) 112 * 113 * The '.', '..' and the end of directory markers have fixed cookies which 114 * cannot collide with the cookies generated by other entries. The cookies 115 * for the other entries are generated based on the memory address on which 116 * stores their information is stored. 117 * 118 * DragonFly binaries use 64-bit cookies. We mask-off the signed bit to 119 * ensure that cookie 'offsets' are positive. 120 */ 121 #ifdef _KERNEL 122 123 #define TMPFS_ROOTINO ((ino_t)2) 124 125 #define TMPFS_DIRCOOKIE_DOT 0 126 #define TMPFS_DIRCOOKIE_DOTDOT 1 127 #define TMPFS_DIRCOOKIE_EOF ((off_t)0x7FFFFFFFFFFFFFFFLLU) 128 129 static __inline 130 off_t 131 tmpfs_dircookie(struct tmpfs_dirent *de) 132 { 133 return ((off_t)((uintptr_t)de >> 1) & 0x7FFFFFFFFFFFFFFFLLU); 134 } 135 136 /* 137 * WARNING! Caller should never try to actually access a tmpfs dirent 138 * structure from a cookiedir() conversion. It is used strictly 139 * for RBTREE operations. 140 */ 141 static __inline 142 void * 143 tmpfs_cookiedir(off_t off) 144 { 145 return ((void *)((uintptr_t)off << 1)); 146 } 147 148 #endif /* _KERNEL */ 149 150 /* --------------------------------------------------------------------- */ 151 152 /* 153 * Internal representation of a tmpfs file system node. 154 * 155 * This structure is splitted in two parts: one holds attributes common 156 * to all file types and the other holds data that is only applicable to 157 * a particular type. The code must be careful to only access those 158 * attributes that are actually allowed by the node's type. 159 */ 160 struct tmpfs_node { 161 /* Doubly-linked list entry which links all existing nodes for a 162 * single file system. This is provided to ease the removal of 163 * all nodes during the unmount operation. */ 164 LIST_ENTRY(tmpfs_node) tn_entries; 165 166 /* The node's type. Any of 'VBLK', 'VCHR', 'VDIR', 'VFIFO', 167 * 'VLNK', 'VREG' and 'VSOCK' is allowed. The usage of vnode 168 * types instead of a custom enumeration is to make things simpler 169 * and faster, as we do not need to convert between two types. */ 170 enum vtype tn_type; 171 172 /* Node identifier. */ 173 ino_t tn_id; 174 175 /* Node's internal status. This is used by several file system 176 * operations to do modifications to the node in a delayed 177 * fashion. */ 178 int tn_blksize; /* small file optimization */ 179 int tn_status; 180 #define TMPFS_NODE_ACCESSED (1 << 1) 181 #define TMPFS_NODE_MODIFIED (1 << 2) 182 #define TMPFS_NODE_CHANGED (1 << 3) 183 184 /* The node size. It does not necessarily match the real amount 185 * of memory consumed by it. */ 186 off_t tn_size; 187 188 /* Generic node attributes. */ 189 uid_t tn_uid; 190 gid_t tn_gid; 191 mode_t tn_mode; 192 u_int tn_flags; 193 nlink_t tn_links; /* atomic ops req */ 194 long tn_atime; 195 long tn_atimensec; 196 long tn_mtime; 197 long tn_mtimensec; 198 long tn_ctime; 199 long tn_ctimensec; 200 unsigned long tn_gen; 201 struct lockf tn_advlock; 202 203 /* As there is a single vnode for each active file within the 204 * system, care has to be taken to avoid allocating more than one 205 * vnode per file. In order to do this, a bidirectional association 206 * is kept between vnodes and nodes. 207 * 208 * Whenever a vnode is allocated, its v_data field is updated to 209 * point to the node it references. At the same time, the node's 210 * tn_vnode field is modified to point to the new vnode representing 211 * it. Further attempts to allocate a vnode for this same node will 212 * result in returning a new reference to the value stored in 213 * tn_vnode. 214 * 215 * May be NULL when the node is unused (that is, no vnode has been 216 * allocated for it or it has been reclaimed). */ 217 struct vnode * tn_vnode; 218 219 /* interlock to protect structure */ 220 struct lock tn_interlock; 221 222 /* 223 * tmpfs vnode state, may specify an allocation in-progress. 224 */ 225 int tn_vpstate; 226 227 /* misc data field for different tn_type node */ 228 union { 229 /* Valid when tn_type == VBLK || tn_type == VCHR. */ 230 dev_t tn_rdev; /*int32_t ?*/ 231 232 /* Valid when tn_type == VDIR. */ 233 struct tn_dir { 234 /* 235 * Pointer to the parent directory. The root 236 * directory has a pointer to itself in this field; 237 * this property identifies the root node. 238 */ 239 struct tmpfs_node * tn_parent; 240 241 /* 242 * Directory entries are indexed by name and also 243 * indexed by cookie. 244 */ 245 struct tmpfs_dirtree tn_dirtree; 246 struct tmpfs_dirtree_cookie tn_cookietree; 247 } tn_dir; 248 249 /* Valid when tn_type == VLNK. */ 250 /* The link's target, allocated from a string pool. */ 251 char * tn_link; 252 253 /* 254 * Valid when tn_type == VREG. 255 * 256 * aobj is used as backing store for the vnode object. It 257 * typically only contains swap assignments, but we also use 258 * it to save the vnode object's vm_page's when the vnode 259 * becomes inactive. 260 */ 261 struct tn_reg { 262 vm_object_t tn_aobj; 263 size_t tn_aobj_pages; 264 int tn_pages_in_aobj; 265 } tn_reg; 266 267 /* Valid when tn_type = VFIFO */ 268 struct tn_fifo { 269 int (*tn_fo_read) (struct file *fp, struct uio *uio, 270 struct ucred *cred, int flags); 271 int (*tn_fo_write) (struct file *fp, struct uio *uio, 272 struct ucred *cred, int flags); 273 } tn_fifo; 274 } tn_spec; 275 }; 276 277 /* Only userspace needs this */ 278 #define VTOI(vp) ((struct tmpfs_node *)(vp)->v_data) 279 280 #ifdef _KERNEL 281 LIST_HEAD(tmpfs_node_list, tmpfs_node); 282 283 #define tn_rdev tn_spec.tn_rdev 284 #define tn_dir tn_spec.tn_dir 285 #define tn_link tn_spec.tn_link 286 #define tn_reg tn_spec.tn_reg 287 #define tn_fifo tn_spec.tn_fifo 288 289 #define TMPFS_NODE_LOCK(node) lockmgr(&(node)->tn_interlock, LK_EXCLUSIVE|LK_RETRY) 290 #define TMPFS_NODE_LOCK_SH(node) lockmgr(&(node)->tn_interlock, LK_SHARED|LK_RETRY) 291 #define TMPFS_NODE_UNLOCK(node) lockmgr(&(node)->tn_interlock, LK_RELEASE) 292 #define TMPFS_NODE_MTX(node) (&(node)->tn_interlock) 293 294 #ifdef INVARIANTS 295 #define TMPFS_ASSERT_LOCKED(node) do { \ 296 KKASSERT(node != NULL); \ 297 KKASSERT(node->tn_vnode != NULL); \ 298 if (!vn_islocked(node->tn_vnode) && \ 299 (lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE )) \ 300 panic("tmpfs: node is not locked: %p", node); \ 301 } while (0) 302 #define TMPFS_ASSERT_ELOCKED(node) do { \ 303 KKASSERT((node) != NULL); \ 304 KKASSERT(lockstatus(TMPFS_NODE_MTX(node), curthread) == LK_EXCLUSIVE); \ 305 } while (0) 306 #else 307 #define TMPFS_ASSERT_LOCKED(node) (void)0 308 #define TMPFS_ASSERT_ELOCKED(node) (void)0 309 #endif /* INVARIANTS */ 310 311 #define TMPFS_VNODE_DOOMED 0x0001 312 /* --------------------------------------------------------------------- */ 313 314 /* 315 * Internal representation of a tmpfs mount point. 316 */ 317 struct tmpfs_mount { 318 struct mount *tm_mount; 319 320 /* Maximum number of memory pages available for use by the file 321 * system, set during mount time. This variable must never be 322 * used directly as it may be bigger than the current amount of 323 * free memory; in the extreme case, it will hold the SIZE_MAX 324 * value. Instead, use the TMPFS_PAGES_MAX macro. */ 325 long tm_pages_max; 326 327 /* Number of pages in use by the file system. Cannot be bigger 328 * than the value returned by TMPFS_PAGES_MAX in any case. */ 329 long tm_pages_used; 330 331 /* Pointer to the node representing the root directory of this 332 * file system. */ 333 struct tmpfs_node * tm_root; 334 335 /* Maximum number of possible nodes for this file system; set 336 * during mount time. We need a hard limit on the maximum number 337 * of nodes to avoid allocating too much of them; their objects 338 * cannot be released until the file system is unmounted. 339 * Otherwise, we could easily run out of memory by creating lots 340 * of empty files and then simply removing them. */ 341 ino_t tm_nodes_max; 342 343 /* Number of nodes currently that are in use. */ 344 ino_t tm_nodes_inuse; 345 346 /* maximum representable file size */ 347 u_int64_t tm_maxfilesize; 348 349 /* Nodes are organized in two different lists. The used list 350 * contains all nodes that are currently used by the file system; 351 * i.e., they refer to existing files. The available list contains 352 * all nodes that are currently available for use by new files. 353 * Nodes must be kept in this list (instead of deleting them) 354 * because we need to keep track of their generation number (tn_gen 355 * field). 356 * 357 * Note that nodes are lazily allocated: if the available list is 358 * empty and we have enough space to create more nodes, they will be 359 * created and inserted in the used list. Once these are released, 360 * they will go into the available list, remaining alive until the 361 * file system is unmounted. */ 362 struct tmpfs_node_list tm_nodes_used; 363 364 /* Per-mount malloc zones for tmpfs nodes, names, and dirents */ 365 struct malloc_type *tm_node_zone_obj; 366 struct malloc_type *tm_dirent_zone_obj; 367 struct malloc_type *tm_name_zone; 368 369 ino_t tm_ino; 370 int tm_flags; 371 372 struct netexport tm_export; 373 374 struct mount *tm_mnt; 375 }; 376 377 #define TMPFS_LOCK(tm) lwkt_gettoken(&(tm)->tm_mount->mnt_token) 378 #define TMPFS_UNLOCK(tm) lwkt_reltoken(&(tm)->tm_mount->mnt_token) 379 380 /* --------------------------------------------------------------------- */ 381 382 /* 383 * This structure maps a file identifier to a tmpfs node. Used by the 384 * NFS code. 385 */ 386 struct tmpfs_fid { 387 uint16_t tf_len; 388 uint16_t tf_pad; 389 ino_t tf_id; 390 unsigned long tf_gen; 391 } __packed; 392 393 /* --------------------------------------------------------------------- */ 394 395 /* 396 * Prototypes for tmpfs_subr.c. 397 */ 398 399 int tmpfs_alloc_node(struct tmpfs_mount *, enum vtype, 400 uid_t uid, gid_t gid, mode_t mode, char *, int, int, 401 struct tmpfs_node **); 402 void tmpfs_free_node(struct tmpfs_mount *, struct tmpfs_node *); 403 int tmpfs_alloc_dirent(struct tmpfs_mount *, struct tmpfs_node *, 404 const char *, uint16_t, struct tmpfs_dirent **); 405 void tmpfs_free_dirent(struct tmpfs_mount *, struct tmpfs_dirent *); 406 int tmpfs_alloc_vp(struct mount *, struct tmpfs_node *, 407 struct tmpfs_node *, int, struct vnode **); 408 int tmpfs_alloc_file(struct vnode *, struct vnode **, struct vattr *, 409 struct namecache *, struct ucred *, char *); 410 void tmpfs_dir_attach_locked(struct tmpfs_node *, struct tmpfs_dirent *); 411 void tmpfs_dir_detach_locked(struct tmpfs_node *, struct tmpfs_dirent *); 412 struct tmpfs_dirent * tmpfs_dir_lookup(struct tmpfs_node *node, 413 struct tmpfs_node *f, 414 struct namecache *ncp); 415 int tmpfs_dir_getdotdent(struct tmpfs_node *, struct uio *); 416 int tmpfs_dir_getdotdotdent(struct tmpfs_mount *, 417 struct tmpfs_node *, struct uio *); 418 struct tmpfs_dirent * tmpfs_dir_lookupbycookie(struct tmpfs_node *, off_t, 419 int); 420 int tmpfs_dir_getdents(struct tmpfs_node *, struct uio *, off_t *); 421 int tmpfs_reg_resize(struct vnode *, off_t, int); 422 int tmpfs_chflags(struct vnode *, u_long, struct ucred *); 423 int tmpfs_chmod(struct vnode *, mode_t, struct ucred *); 424 int tmpfs_chown(struct vnode *, uid_t, gid_t, struct ucred *); 425 int tmpfs_chsize(struct vnode *, u_quad_t, struct ucred *); 426 int tmpfs_chtimes(struct vnode *, struct timespec *, struct timespec *, 427 int, struct ucred *); 428 void tmpfs_itimes(struct vnode *, const struct timespec *, 429 const struct timespec *); 430 431 void tmpfs_node_init(struct tmpfs_node *node); 432 void tmpfs_node_uninit(struct tmpfs_node *node); 433 void tmpfs_update(struct vnode *); 434 int tmpfs_truncate(struct vnode *, off_t); 435 void tmpfs_lock4(struct tmpfs_node *node1, struct tmpfs_node *node2, 436 struct tmpfs_node *node3, struct tmpfs_node *node4); 437 void tmpfs_unlock4(struct tmpfs_node *node1, struct tmpfs_node *node2, 438 struct tmpfs_node *node3, struct tmpfs_node *node4); 439 440 /* --------------------------------------------------------------------- */ 441 442 /* 443 * Convenience macros to simplify some logical expressions. 444 */ 445 #define IMPLIES(a, b) (!(a) || (b)) 446 #define IFF(a, b) (IMPLIES(a, b) && IMPLIES(b, a)) 447 448 /* --------------------------------------------------------------------- */ 449 450 /* 451 * Checks that the directory entry pointed by 'de' matches the name 'name' 452 * with a length of 'len'. 453 */ 454 #define TMPFS_DIRENT_MATCHES(de, name, len) \ 455 (de->td_namelen == (uint16_t)len && \ 456 bcmp((de)->td_name, (name), (de)->td_namelen) == 0) 457 458 /* --------------------------------------------------------------------- */ 459 460 /* 461 * Ensures that the node pointed by 'node' is a directory and that its 462 * contents are consistent with respect to directories. 463 */ 464 #define TMPFS_VALIDATE_DIR(node) do { \ 465 KKASSERT((node)->tn_type == VDIR); \ 466 KKASSERT((node)->tn_size % sizeof(struct tmpfs_dirent) == 0); \ 467 } while(0) 468 469 /* --------------------------------------------------------------------- */ 470 471 /* 472 * Macros/functions to convert from generic data structures to tmpfs 473 * specific ones. Kernel code use VP_TO_TMPFS_NODE() instead of VTOI(). 474 */ 475 476 static inline 477 struct tmpfs_mount * 478 VFS_TO_TMPFS(struct mount *mp) 479 { 480 struct tmpfs_mount *tmp; 481 482 KKASSERT((mp) != NULL && (mp)->mnt_data != NULL); 483 tmp = (struct tmpfs_mount *)(mp)->mnt_data; 484 return tmp; 485 } 486 487 static inline 488 struct tmpfs_node * 489 VP_TO_TMPFS_NODE(struct vnode *vp) 490 { 491 struct tmpfs_node *node; 492 493 KKASSERT((vp) != NULL && (vp)->v_data != NULL); 494 node = (struct tmpfs_node *)vp->v_data; 495 return node; 496 } 497 498 static inline 499 struct tmpfs_node * 500 VP_TO_TMPFS_DIR(struct vnode *vp) 501 { 502 struct tmpfs_node *node; 503 504 node = VP_TO_TMPFS_NODE(vp); 505 TMPFS_VALIDATE_DIR(node); 506 return node; 507 } 508 509 /* --------------------------------------------------------------------- */ 510 /* 511 * buffer cache size 512 */ 513 #define TMPFS_BLKSIZE 16384 /* buffer cache size*/ 514 #define TMPFS_BLKMASK (TMPFS_BLKSIZE - 1) 515 #define TMPFS_BLKMASK64 ((off_t)(TMPFS_BLKSIZE - 1)) 516 #endif /* _KERNEL */ 517 518 #endif /* _VFS_TMPFS_TMPFS_H_ */ 519