1 /* $NetBSD: tmpfs_vfsops.c,v 1.78 2022/11/10 10:54:14 hannken Exp $ */ 2 3 /* 4 * Copyright (c) 2005, 2006, 2007 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/cdefs.h> 45 __KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.78 2022/11/10 10:54:14 hannken Exp $"); 46 47 #include <sys/param.h> 48 #include <sys/atomic.h> 49 #include <sys/types.h> 50 #include <sys/kmem.h> 51 #include <sys/mount.h> 52 #include <sys/stat.h> 53 #include <sys/systm.h> 54 #include <sys/vnode.h> 55 #include <sys/kauth.h> 56 #include <sys/module.h> 57 58 #include <miscfs/genfs/genfs.h> 59 #include <fs/tmpfs/tmpfs.h> 60 #include <fs/tmpfs/tmpfs_args.h> 61 62 MODULE(MODULE_CLASS_VFS, tmpfs, NULL); 63 64 struct pool tmpfs_dirent_pool; 65 struct pool tmpfs_node_pool; 66 67 void 68 tmpfs_init(void) 69 { 70 71 pool_init(&tmpfs_dirent_pool, sizeof(tmpfs_dirent_t), 0, 0, 0, 72 "tmpfs_dirent", &pool_allocator_nointr, IPL_NONE); 73 pool_init(&tmpfs_node_pool, sizeof(tmpfs_node_t), 0, 0, 0, 74 "tmpfs_node", &pool_allocator_nointr, IPL_NONE); 75 } 76 77 void 78 tmpfs_done(void) 79 { 80 81 pool_destroy(&tmpfs_dirent_pool); 82 pool_destroy(&tmpfs_node_pool); 83 } 84 85 int 86 tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 87 { 88 struct tmpfs_args *args = data; 89 tmpfs_mount_t *tmp; 90 tmpfs_node_t *root; 91 struct vattr va; 92 struct vnode *vp; 93 uint64_t memlimit; 94 ino_t nodes; 95 int error, flags; 96 bool set_memlimit; 97 bool set_nodes; 98 99 if (args == NULL) 100 return EINVAL; 101 102 /* Validate the version. */ 103 if (*data_len < sizeof(*args) || 104 args->ta_version != TMPFS_ARGS_VERSION) 105 return EINVAL; 106 107 /* Handle retrieval of mount point arguments. */ 108 if (mp->mnt_flag & MNT_GETARGS) { 109 if (mp->mnt_data == NULL) 110 return EIO; 111 tmp = VFS_TO_TMPFS(mp); 112 113 args->ta_version = TMPFS_ARGS_VERSION; 114 args->ta_nodes_max = tmp->tm_nodes_max; 115 args->ta_size_max = tmp->tm_mem_limit; 116 117 root = tmp->tm_root; 118 args->ta_root_uid = root->tn_uid; 119 args->ta_root_gid = root->tn_gid; 120 args->ta_root_mode = root->tn_mode; 121 122 *data_len = sizeof(*args); 123 return 0; 124 } 125 126 127 /* Prohibit mounts if there is not enough memory. */ 128 if (tmpfs_mem_info(true) < uvmexp.freetarg) 129 return EINVAL; 130 131 /* Check for invalid uid and gid arguments */ 132 if (args->ta_root_uid == VNOVAL || args->ta_root_gid == VNOVAL) 133 return EINVAL; 134 135 /* Get the memory usage limit for this file-system. */ 136 if (args->ta_size_max < PAGE_SIZE) { 137 memlimit = UINT64_MAX; 138 set_memlimit = false; 139 } else { 140 memlimit = args->ta_size_max; 141 set_memlimit = true; 142 } 143 KASSERT(memlimit > 0); 144 145 if (args->ta_nodes_max <= 3) { 146 nodes = 3 + (memlimit / 1024); 147 set_nodes = false; 148 } else { 149 nodes = args->ta_nodes_max; 150 set_nodes = true; 151 } 152 nodes = MIN(nodes, INT_MAX); 153 KASSERT(nodes >= 3); 154 155 if (mp->mnt_flag & MNT_UPDATE) { 156 tmp = VFS_TO_TMPFS(mp); 157 if (set_nodes && nodes < tmp->tm_nodes_cnt) 158 return EBUSY; 159 if ((mp->mnt_iflag & IMNT_WANTRDONLY)) { 160 /* Changing from read/write to read-only. */ 161 flags = WRITECLOSE; 162 if ((mp->mnt_flag & MNT_FORCE)) 163 flags |= FORCECLOSE; 164 error = vflush(mp, NULL, flags); 165 if (error) 166 return error; 167 } 168 if (set_memlimit) { 169 if ((error = tmpfs_mntmem_set(tmp, memlimit)) != 0) 170 return error; 171 } 172 if (set_nodes) 173 tmp->tm_nodes_max = nodes; 174 root = tmp->tm_root; 175 root->tn_uid = args->ta_root_uid; 176 root->tn_gid = args->ta_root_gid; 177 root->tn_mode = args->ta_root_mode; 178 return 0; 179 } 180 181 mp->mnt_flag |= MNT_LOCAL; 182 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN; 183 mp->mnt_fs_bshift = PAGE_SHIFT; 184 mp->mnt_dev_bshift = DEV_BSHIFT; 185 mp->mnt_iflag |= IMNT_MPSAFE | IMNT_CAN_RWTORO | IMNT_SHRLOOKUP | 186 IMNT_NCLOOKUP; 187 vfs_getnewfsid(mp); 188 189 /* Allocate the tmpfs mount structure and fill it. */ 190 tmp = kmem_zalloc(sizeof(tmpfs_mount_t), KM_SLEEP); 191 tmp->tm_nodes_max = nodes; 192 tmp->tm_nodes_cnt = 0; 193 LIST_INIT(&tmp->tm_nodes); 194 195 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 196 tmpfs_mntmem_init(tmp, memlimit); 197 mp->mnt_data = tmp; 198 199 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 200 mp->mnt_op->vfs_name, mp, curlwp); 201 if (error) 202 goto errout; 203 204 /* Allocate the root node. */ 205 vattr_null(&va); 206 va.va_type = VDIR; 207 va.va_mode = args->ta_root_mode & ALLPERMS; 208 va.va_uid = args->ta_root_uid; 209 va.va_gid = args->ta_root_gid; 210 error = vcache_new(mp, NULL, &va, NOCRED, NULL, &vp); 211 if (error) 212 goto errout; 213 KASSERT(vp != NULL); 214 root = VP_TO_TMPFS_NODE(vp); 215 KASSERT(root != NULL); 216 217 /* 218 * Parent of the root inode is itself. Also, root inode has no 219 * directory entry (i.e. is never attached), thus hold an extra 220 * reference (link) for it. 221 */ 222 root->tn_links++; 223 root->tn_spec.tn_dir.tn_parent = root; 224 tmp->tm_root = root; 225 vrele(vp); 226 227 return 0; 228 229 errout: 230 mp->mnt_data = NULL; 231 tmpfs_mntmem_destroy(tmp); 232 mutex_destroy(&tmp->tm_lock); 233 kmem_free(tmp, sizeof(*tmp)); 234 235 return error; 236 } 237 238 int 239 tmpfs_start(struct mount *mp, int flags) 240 { 241 242 return 0; 243 } 244 245 int 246 tmpfs_unmount(struct mount *mp, int mntflags) 247 { 248 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 249 tmpfs_node_t *node, *cnode; 250 int error, flags = 0; 251 252 /* Handle forced unmounts. */ 253 if (mntflags & MNT_FORCE) 254 flags |= FORCECLOSE; 255 256 /* Finalize all pending I/O. */ 257 error = vflush(mp, NULL, flags); 258 if (error != 0) 259 return error; 260 261 /* 262 * First round, detach and destroy all directory entries. 263 * Also, clear the pointers to the vnodes - they are gone. 264 */ 265 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 266 tmpfs_dirent_t *de; 267 268 node->tn_vnode = NULL; 269 if (node->tn_type != VDIR) { 270 continue; 271 } 272 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) { 273 cnode = de->td_node; 274 if (cnode && cnode != TMPFS_NODE_WHITEOUT) { 275 cnode->tn_vnode = NULL; 276 } 277 tmpfs_dir_detach(node, de); 278 tmpfs_free_dirent(tmp, de); 279 } 280 /* Extra virtual entry (itself for the root). */ 281 node->tn_links--; 282 } 283 284 /* Release the reference on root (diagnostic). */ 285 node = tmp->tm_root; 286 node->tn_links--; 287 288 /* Second round, destroy all inodes. */ 289 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) { 290 tmpfs_free_node(tmp, node); 291 } 292 293 /* Throw away the tmpfs_mount structure. */ 294 tmpfs_mntmem_destroy(tmp); 295 mutex_destroy(&tmp->tm_lock); 296 kmem_free(tmp, sizeof(*tmp)); 297 mp->mnt_data = NULL; 298 299 return 0; 300 } 301 302 int 303 tmpfs_root(struct mount *mp, int lktype, vnode_t **vpp) 304 { 305 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root; 306 int error; 307 308 error = vcache_get(mp, &node, sizeof(node), vpp); 309 if (error) 310 return error; 311 error = vn_lock(*vpp, lktype); 312 if (error) { 313 vrele(*vpp); 314 *vpp = NULL; 315 return error; 316 } 317 318 return 0; 319 } 320 321 int 322 tmpfs_vget(struct mount *mp, ino_t ino, int lktype, vnode_t **vpp) 323 { 324 325 return EOPNOTSUPP; 326 } 327 328 int 329 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int lktype, vnode_t **vpp) 330 { 331 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 332 tmpfs_node_t *node; 333 tmpfs_fid_t tfh; 334 int error; 335 336 if (fhp->fid_len != sizeof(tmpfs_fid_t)) { 337 return EINVAL; 338 } 339 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t)); 340 341 mutex_enter(&tmp->tm_lock); 342 /* XXX big oof .. use a better data structure */ 343 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 344 if (node->tn_id == tfh.tf_id) { 345 /* Prevent this node from disappearing. */ 346 atomic_inc_32(&node->tn_holdcount); 347 break; 348 } 349 } 350 mutex_exit(&tmp->tm_lock); 351 if (node == NULL) 352 return ESTALE; 353 354 error = vcache_get(mp, &node, sizeof(node), vpp); 355 /* If this node has been reclaimed free it now. */ 356 if (atomic_dec_32_nv(&node->tn_holdcount) == TMPFS_NODE_RECLAIMED) { 357 KASSERT(error != 0); 358 tmpfs_free_node(tmp, node); 359 } 360 if (error) 361 return (error == ENOENT ? ESTALE : error); 362 error = vn_lock(*vpp, lktype); 363 if (error) { 364 vrele(*vpp); 365 *vpp = NULL; 366 return error; 367 } 368 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) { 369 vput(*vpp); 370 *vpp = NULL; 371 return ESTALE; 372 } 373 374 return 0; 375 } 376 377 int 378 tmpfs_vptofh(vnode_t *vp, struct fid *fhp, size_t *fh_size) 379 { 380 tmpfs_fid_t tfh; 381 tmpfs_node_t *node; 382 383 if (*fh_size < sizeof(tmpfs_fid_t)) { 384 *fh_size = sizeof(tmpfs_fid_t); 385 return E2BIG; 386 } 387 *fh_size = sizeof(tmpfs_fid_t); 388 node = VP_TO_TMPFS_NODE(vp); 389 390 memset(&tfh, 0, sizeof(tfh)); 391 tfh.tf_len = sizeof(tmpfs_fid_t); 392 tfh.tf_gen = TMPFS_NODE_GEN(node); 393 tfh.tf_id = node->tn_id; 394 memcpy(fhp, &tfh, sizeof(tfh)); 395 396 return 0; 397 } 398 399 int 400 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 401 { 402 tmpfs_mount_t *tmp; 403 fsfilcnt_t freenodes; 404 size_t avail; 405 406 tmp = VFS_TO_TMPFS(mp); 407 408 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 409 410 mutex_enter(&tmp->tm_acc_lock); 411 avail = tmpfs_pages_avail(tmp); 412 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 413 sbp->f_bavail = sbp->f_bfree = avail; 414 sbp->f_bresvd = 0; 415 416 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 417 avail * PAGE_SIZE / sizeof(tmpfs_node_t)); 418 419 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 420 sbp->f_favail = sbp->f_ffree = freenodes; 421 sbp->f_fresvd = 0; 422 mutex_exit(&tmp->tm_acc_lock); 423 424 copy_statvfs_info(sbp, mp); 425 426 return 0; 427 } 428 429 int 430 tmpfs_sync(struct mount *mp, int waitfor, kauth_cred_t uc) 431 { 432 433 return 0; 434 } 435 436 int 437 tmpfs_snapshot(struct mount *mp, vnode_t *vp, struct timespec *ctime) 438 { 439 440 return EOPNOTSUPP; 441 } 442 443 /* 444 * tmpfs vfs operations. 445 */ 446 447 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 448 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 449 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 450 451 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 452 &tmpfs_fifoop_opv_desc, 453 &tmpfs_specop_opv_desc, 454 &tmpfs_vnodeop_opv_desc, 455 NULL, 456 }; 457 458 struct vfsops tmpfs_vfsops = { 459 .vfs_name = MOUNT_TMPFS, 460 .vfs_min_mount_data = sizeof (struct tmpfs_args), 461 .vfs_mount = tmpfs_mount, 462 .vfs_start = tmpfs_start, 463 .vfs_unmount = tmpfs_unmount, 464 .vfs_root = tmpfs_root, 465 .vfs_quotactl = (void *)eopnotsupp, 466 .vfs_statvfs = tmpfs_statvfs, 467 .vfs_sync = tmpfs_sync, 468 .vfs_vget = tmpfs_vget, 469 .vfs_loadvnode = tmpfs_loadvnode, 470 .vfs_newvnode = tmpfs_newvnode, 471 .vfs_fhtovp = tmpfs_fhtovp, 472 .vfs_vptofh = tmpfs_vptofh, 473 .vfs_init = tmpfs_init, 474 .vfs_done = tmpfs_done, 475 .vfs_snapshot = tmpfs_snapshot, 476 .vfs_extattrctl = vfs_stdextattrctl, 477 .vfs_suspendctl = genfs_suspendctl, 478 .vfs_renamelock_enter = genfs_renamelock_enter, 479 .vfs_renamelock_exit = genfs_renamelock_exit, 480 .vfs_fsync = (void *)eopnotsupp, 481 .vfs_opv_descs = tmpfs_vnodeopv_descs 482 }; 483 484 static int 485 tmpfs_modcmd(modcmd_t cmd, void *arg) 486 { 487 488 switch (cmd) { 489 case MODULE_CMD_INIT: 490 return vfs_attach(&tmpfs_vfsops); 491 case MODULE_CMD_FINI: 492 return vfs_detach(&tmpfs_vfsops); 493 default: 494 return ENOTTY; 495 } 496 } 497
Indexes created Sun Sep 21 14:09:52 GMT 2025