1 /* $NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2005 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 /* 34 * Efficient memory file system. 35 * 36 * tmpfs is a file system that uses NetBSD's virtual memory sub-system 37 * (the well-known UVM) to store file data and metadata in an efficient 38 * way. This means that it does not follow the structure of an on-disk 39 * file system because it simply does not need to. Instead, it uses 40 * memory-specific data structures and algorithms to automatically 41 * allocate and release resources. 42 */ 43 44 #include <sys/conf.h> 45 #include <sys/param.h> 46 #include <sys/limits.h> 47 #include <sys/lock.h> 48 #include <sys/mutex.h> 49 #include <sys/kernel.h> 50 #include <sys/stat.h> 51 #include <sys/systm.h> 52 #include <sys/sysctl.h> 53 #include <sys/objcache.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_object.h> 57 #include <vm/vm_param.h> 58 59 #include <vfs/tmpfs/tmpfs.h> 60 #include <vfs/tmpfs/tmpfs_vnops.h> 61 #include <vfs/tmpfs/tmpfs_args.h> 62 63 /* 64 * Default permission for root node 65 */ 66 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH) 67 68 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures"); 69 70 /* --------------------------------------------------------------------- */ 71 72 static int tmpfs_mount(struct mount *, char *, caddr_t, struct ucred *); 73 static int tmpfs_unmount(struct mount *, int); 74 static int tmpfs_root(struct mount *, struct vnode **); 75 static int tmpfs_fhtovp(struct mount *, struct vnode *, struct fid *, struct vnode **); 76 static int tmpfs_statfs(struct mount *, struct statfs *, struct ucred *cred); 77 78 /* --------------------------------------------------------------------- */ 79 int 80 tmpfs_node_ctor(void *obj, void *privdata, int flags) 81 { 82 struct tmpfs_node *node = (struct tmpfs_node *)obj; 83 84 node->tn_gen++; 85 node->tn_size = 0; 86 node->tn_status = 0; 87 node->tn_flags = 0; 88 node->tn_links = 0; 89 node->tn_vnode = NULL; 90 node->tn_vpstate = TMPFS_VNODE_WANT; 91 bzero(&node->tn_spec, sizeof(node->tn_spec)); 92 93 return (1); 94 } 95 96 static void 97 tmpfs_node_dtor(void *obj, void *privdata) 98 { 99 struct tmpfs_node *node = (struct tmpfs_node *)obj; 100 node->tn_type = VNON; 101 node->tn_vpstate = TMPFS_VNODE_DOOMED; 102 } 103 104 static void* 105 tmpfs_node_init(void *args, int flags) 106 { 107 struct tmpfs_node *node = (struct tmpfs_node *)objcache_malloc_alloc(args, flags); 108 if (node == NULL) 109 return (NULL); 110 node->tn_id = 0; 111 112 lockinit(&node->tn_interlock, "tmpfs node interlock", 0, LK_CANRECURSE); 113 node->tn_gen = karc4random(); 114 115 return node; 116 } 117 118 static void 119 tmpfs_node_fini(void *obj, void *args) 120 { 121 struct tmpfs_node *node = (struct tmpfs_node *)obj; 122 lockuninit(&node->tn_interlock); 123 objcache_malloc_free(obj, args); 124 } 125 126 static int 127 tmpfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred) 128 { 129 struct tmpfs_mount *tmp; 130 struct tmpfs_node *root; 131 struct tmpfs_args args; 132 vm_pindex_t pages; 133 vm_pindex_t pages_limit; 134 ino_t nodes; 135 u_int64_t maxfsize; 136 int error; 137 /* Size counters. */ 138 ino_t nodes_max; 139 off_t size_max; 140 size_t maxfsize_max; 141 size_t size; 142 143 /* Root node attributes. */ 144 uid_t root_uid = cred->cr_uid; 145 gid_t root_gid = cred->cr_gid; 146 mode_t root_mode = (VREAD | VWRITE); 147 148 if (mp->mnt_flag & MNT_UPDATE) { 149 /* XXX: There is no support yet to update file system 150 * settings. Should be added. */ 151 152 return EOPNOTSUPP; 153 } 154 155 /* 156 * mount info 157 */ 158 bzero(&args, sizeof(args)); 159 size_max = 0; 160 nodes_max = 0; 161 maxfsize_max = 0; 162 163 if (path) { 164 if (data) { 165 error = copyin(data, &args, sizeof(args)); 166 if (error) 167 return (error); 168 } 169 size_max = args.ta_size_max; 170 nodes_max = args.ta_nodes_max; 171 maxfsize_max = args.ta_maxfsize_max; 172 root_uid = args.ta_root_uid; 173 root_gid = args.ta_root_gid; 174 root_mode = args.ta_root_mode; 175 } 176 177 /* 178 * If mount by non-root, then verify that user has necessary 179 * permissions on the device. 180 */ 181 if (cred->cr_uid != 0) { 182 root_mode = VREAD; 183 if ((mp->mnt_flag & MNT_RDONLY) == 0) 184 root_mode |= VWRITE; 185 } 186 187 pages_limit = vm_swap_max + vmstats.v_page_count / 2; 188 189 if (size_max == 0) { 190 pages = pages_limit / 2; 191 } else if (size_max < PAGE_SIZE) { 192 pages = 1; 193 } else if (OFF_TO_IDX(size_max) > pages_limit) { 194 /* 195 * do not force pages = pages_limit for this case, otherwise 196 * we might not honor tmpfs size requests from /etc/fstab 197 * during boot because they are mounted prior to swap being 198 * turned on. 199 */ 200 pages = OFF_TO_IDX(size_max); 201 } else { 202 pages = OFF_TO_IDX(size_max); 203 } 204 205 if (nodes_max == 0) 206 nodes = 3 + pages * PAGE_SIZE / 1024; 207 else if (nodes_max < 3) 208 nodes = 3; 209 else if (nodes_max > pages) 210 nodes = pages; 211 else 212 nodes = nodes_max; 213 214 maxfsize = IDX_TO_OFF(pages_limit); 215 if (maxfsize_max != 0 && maxfsize > maxfsize_max) 216 maxfsize = maxfsize_max; 217 218 /* Allocate the tmpfs mount structure and fill it. */ 219 tmp = kmalloc(sizeof(*tmp), M_TMPFSMNT, M_WAITOK | M_ZERO); 220 221 lockinit(&(tmp->allnode_lock), "tmpfs allnode lock", 0, LK_CANRECURSE); 222 tmp->tm_nodes_max = nodes; 223 tmp->tm_nodes_inuse = 0; 224 tmp->tm_maxfilesize = maxfsize; 225 LIST_INIT(&tmp->tm_nodes_used); 226 227 tmp->tm_pages_max = pages; 228 tmp->tm_pages_used = 0; 229 230 kmalloc_create(&tmp->tm_node_zone, "tmpfs node"); 231 kmalloc_create(&tmp->tm_dirent_zone, "tmpfs dirent"); 232 kmalloc_create(&tmp->tm_name_zone, "tmpfs name zone"); 233 234 kmalloc_raise_limit(tmp->tm_node_zone, sizeof(struct tmpfs_node) * 235 tmp->tm_nodes_max); 236 237 tmp->tm_node_zone_malloc_args.objsize = sizeof(struct tmpfs_node); 238 tmp->tm_node_zone_malloc_args.mtype = tmp->tm_node_zone; 239 240 tmp->tm_dirent_zone_malloc_args.objsize = sizeof(struct tmpfs_dirent); 241 tmp->tm_dirent_zone_malloc_args.mtype = tmp->tm_dirent_zone; 242 243 tmp->tm_dirent_pool = objcache_create( "tmpfs dirent cache", 244 0, 0, 245 NULL, NULL, NULL, 246 objcache_malloc_alloc, objcache_malloc_free, 247 &tmp->tm_dirent_zone_malloc_args); 248 tmp->tm_node_pool = objcache_create( "tmpfs node cache", 249 0, 0, 250 tmpfs_node_ctor, tmpfs_node_dtor, NULL, 251 tmpfs_node_init, tmpfs_node_fini, 252 &tmp->tm_node_zone_malloc_args); 253 254 tmp->tm_ino = 2; 255 256 /* Allocate the root node. */ 257 error = tmpfs_alloc_node(tmp, VDIR, root_uid, root_gid, 258 root_mode & ALLPERMS, NULL, 259 VNOVAL, VNOVAL, &root); 260 261 /* 262 * We are backed by swap, set snocache chflags flag so we 263 * don't trip over swapcache. 264 */ 265 root->tn_flags = SF_NOCACHE; 266 267 if (error != 0 || root == NULL) { 268 objcache_destroy(tmp->tm_node_pool); 269 objcache_destroy(tmp->tm_dirent_pool); 270 kfree(tmp, M_TMPFSMNT); 271 return error; 272 } 273 KASSERT(root->tn_id >= 0, ("tmpfs root with invalid ino: %d", (int)root->tn_id)); 274 ++root->tn_links; /* prevent destruction */ 275 tmp->tm_root = root; 276 277 mp->mnt_flag |= MNT_LOCAL; 278 #if 0 279 mp->mnt_kern_flag |= MNTK_RD_MPSAFE | MNTK_WR_MPSAFE | MNTK_GA_MPSAFE | 280 MNTK_IN_MPSAFE | MNTK_SG_MPSAFE; 281 #endif 282 mp->mnt_kern_flag |= MNTK_RD_MPSAFE | MNTK_GA_MPSAFE | MNTK_SG_MPSAFE; 283 mp->mnt_kern_flag |= MNTK_WR_MPSAFE; 284 mp->mnt_kern_flag |= MNTK_NOMSYNC; 285 mp->mnt_data = (qaddr_t)tmp; 286 vfs_getnewfsid(mp); 287 288 289 vfs_add_vnodeops(mp, &tmpfs_vnode_vops, &mp->mnt_vn_norm_ops); 290 vfs_add_vnodeops(mp, &tmpfs_fifo_vops, &mp->mnt_vn_fifo_ops); 291 292 copystr("tmpfs", mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size); 293 bzero(mp->mnt_stat.f_mntfromname +size, MNAMELEN - size); 294 bzero(mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname)); 295 copyinstr(path, mp->mnt_stat.f_mntonname, 296 sizeof(mp->mnt_stat.f_mntonname) -1, 297 &size); 298 299 tmpfs_statfs(mp, &mp->mnt_stat, cred); 300 301 return 0; 302 } 303 304 /* --------------------------------------------------------------------- */ 305 306 /* ARGSUSED2 */ 307 static int 308 tmpfs_unmount(struct mount *mp, int mntflags) 309 { 310 int error; 311 int flags = 0; 312 struct tmpfs_mount *tmp; 313 struct tmpfs_node *node; 314 315 /* Handle forced unmounts. */ 316 if (mntflags & MNT_FORCE) 317 flags |= FORCECLOSE; 318 319 tmp = VFS_TO_TMPFS(mp); 320 321 /* 322 * Finalize all pending I/O. In the case of tmpfs we want 323 * to throw all the data away so clean out the buffer cache 324 * and vm objects before calling vflush(). 325 */ 326 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 327 if (node->tn_type == VREG && node->tn_vnode) { 328 ++node->tn_links; 329 TMPFS_NODE_LOCK(node); 330 vx_get(node->tn_vnode); 331 tmpfs_truncate(node->tn_vnode, 0); 332 vx_put(node->tn_vnode); 333 TMPFS_NODE_UNLOCK(node); 334 --node->tn_links; 335 } 336 } 337 error = vflush(mp, 0, flags); 338 if (error != 0) 339 return error; 340 341 /* 342 * First pass get rid of all the directory entries and 343 * vnode associations. This will also destroy the 344 * directory topology and should drop all link counts 345 * to 0 except for the root. 346 * 347 * No vnodes should remain after the vflush above. 348 */ 349 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 350 ++node->tn_links; 351 TMPFS_NODE_LOCK(node); 352 if (node->tn_type == VDIR) { 353 struct tmpfs_dirent *de; 354 355 while ((de = RB_ROOT(&node->tn_dir.tn_dirtree)) != NULL) { 356 tmpfs_dir_detach(node, de); 357 tmpfs_free_dirent(tmp, de); 358 } 359 } 360 KKASSERT(node->tn_vnode == NULL); 361 #if 0 362 vp = node->tn_vnode; 363 if (vp != NULL) { 364 tmpfs_free_vp(vp); 365 vrecycle(vp); 366 node->tn_vnode = NULL; 367 } 368 #endif 369 TMPFS_NODE_UNLOCK(node); 370 --node->tn_links; 371 } 372 373 /* 374 * Allow the root node to be destroyed by dropping the link count 375 * we bumped in the mount code. 376 */ 377 KKASSERT(tmp->tm_root); 378 --tmp->tm_root->tn_links; 379 380 /* 381 * At this point all nodes, including the root node, should have a 382 * link count of 0. The root is not necessarily going to be last. 383 */ 384 while ((node = LIST_FIRST(&tmp->tm_nodes_used)) != NULL) { 385 if (node->tn_links) 386 panic("tmpfs: Dangling nodes during umount (%p)!\n", node); 387 TMPFS_NODE_LOCK(node); 388 tmpfs_free_node(tmp, node); 389 /* eats lock */ 390 } 391 KKASSERT(tmp->tm_root == NULL); 392 393 objcache_destroy(tmp->tm_dirent_pool); 394 objcache_destroy(tmp->tm_node_pool); 395 396 kmalloc_destroy(&tmp->tm_name_zone); 397 kmalloc_destroy(&tmp->tm_dirent_zone); 398 kmalloc_destroy(&tmp->tm_node_zone); 399 400 tmp->tm_node_zone = tmp->tm_dirent_zone = NULL; 401 402 lockuninit(&tmp->allnode_lock); 403 KKASSERT(tmp->tm_pages_used == 0); 404 KKASSERT(tmp->tm_nodes_inuse == 0); 405 406 /* Throw away the tmpfs_mount structure. */ 407 kfree(tmp, M_TMPFSMNT); 408 mp->mnt_data = NULL; 409 410 mp->mnt_flag &= ~MNT_LOCAL; 411 return 0; 412 } 413 414 /* --------------------------------------------------------------------- */ 415 416 static int 417 tmpfs_root(struct mount *mp, struct vnode **vpp) 418 { 419 struct tmpfs_mount *tmp; 420 int error; 421 422 tmp = VFS_TO_TMPFS(mp); 423 if (tmp->tm_root == NULL) { 424 kprintf("tmpfs_root: called without root node %p\n", mp); 425 print_backtrace(-1); 426 *vpp = NULL; 427 error = EINVAL; 428 } else { 429 error = tmpfs_alloc_vp(mp, tmp->tm_root, LK_EXCLUSIVE, vpp); 430 (*vpp)->v_flag |= VROOT; 431 (*vpp)->v_type = VDIR; 432 } 433 return error; 434 } 435 436 /* --------------------------------------------------------------------- */ 437 438 static int 439 tmpfs_fhtovp(struct mount *mp, struct vnode *rootvp, struct fid *fhp, struct vnode **vpp) 440 { 441 boolean_t found; 442 struct tmpfs_fid *tfhp; 443 struct tmpfs_mount *tmp; 444 struct tmpfs_node *node; 445 446 tmp = VFS_TO_TMPFS(mp); 447 448 tfhp = (struct tmpfs_fid *)fhp; 449 if (tfhp->tf_len != sizeof(struct tmpfs_fid)) 450 return EINVAL; 451 452 if (tfhp->tf_id >= tmp->tm_nodes_max) 453 return EINVAL; 454 455 found = FALSE; 456 457 TMPFS_LOCK(tmp); 458 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 459 if (node->tn_id == tfhp->tf_id && 460 node->tn_gen == tfhp->tf_gen) { 461 found = TRUE; 462 break; 463 } 464 } 465 TMPFS_UNLOCK(tmp); 466 467 if (found) 468 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp)); 469 470 return (EINVAL); 471 } 472 473 /* --------------------------------------------------------------------- */ 474 475 /* ARGSUSED2 */ 476 static int 477 tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred) 478 { 479 fsfilcnt_t freenodes; 480 struct tmpfs_mount *tmp; 481 482 tmp = VFS_TO_TMPFS(mp); 483 484 sbp->f_iosize = PAGE_SIZE; 485 sbp->f_bsize = PAGE_SIZE; 486 487 sbp->f_blocks = tmp->tm_pages_max; 488 sbp->f_bavail = tmp->tm_pages_max - tmp->tm_pages_used; 489 sbp->f_bfree = sbp->f_bavail; 490 491 freenodes = tmp->tm_nodes_max - tmp->tm_nodes_inuse; 492 493 sbp->f_files = freenodes + tmp->tm_nodes_inuse; 494 sbp->f_ffree = freenodes; 495 sbp->f_owner = tmp->tm_root->tn_uid; 496 497 return 0; 498 } 499 500 /* --------------------------------------------------------------------- */ 501 502 static int 503 tmpfs_vptofh(struct vnode *vp, struct fid *fhp) 504 { 505 struct tmpfs_node *node; 506 struct tmpfs_fid tfh; 507 node = VP_TO_TMPFS_NODE(vp); 508 memset(&tfh, 0, sizeof(tfh)); 509 tfh.tf_len = sizeof(struct tmpfs_fid); 510 tfh.tf_gen = node->tn_gen; 511 tfh.tf_id = node->tn_id; 512 memcpy(fhp, &tfh, sizeof(tfh)); 513 return (0); 514 } 515 516 /* --------------------------------------------------------------------- */ 517 518 static int 519 tmpfs_checkexp(struct mount *mp, struct sockaddr *nam, int *exflagsp, 520 struct ucred **credanonp) 521 { 522 struct tmpfs_mount *tmp; 523 struct netcred *nc; 524 525 tmp = (struct tmpfs_mount *) mp->mnt_data; 526 nc = vfs_export_lookup(mp, &tmp->tm_export, nam); 527 if (nc == NULL) 528 return (EACCES); 529 530 *exflagsp = nc->netc_exflags; 531 *credanonp = &nc->netc_anon; 532 533 return (0); 534 } 535 536 /* --------------------------------------------------------------------- */ 537 538 /* 539 * tmpfs vfs operations. 540 */ 541 542 static struct vfsops tmpfs_vfsops = { 543 .vfs_mount = tmpfs_mount, 544 .vfs_unmount = tmpfs_unmount, 545 .vfs_root = tmpfs_root, 546 .vfs_statfs = tmpfs_statfs, 547 .vfs_fhtovp = tmpfs_fhtovp, 548 .vfs_vptofh = tmpfs_vptofh, 549 .vfs_sync = vfs_stdsync, 550 .vfs_checkexp = tmpfs_checkexp, 551 }; 552 553 VFS_SET(tmpfs_vfsops, tmpfs, 0); 554 MODULE_VERSION(tmpfs, 1); 555