1 /* $NetBSD: tmpfs_vfsops.c,v 1.68 2016/08/26 21:44:24 dholland 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 1.68 2016/08/26 21:44:24 dholland 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; 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 /* This can never happen? */ 136 if ((args->ta_root_mode & ALLPERMS) == VNOVAL) 137 return EINVAL; 138 139 /* Get the memory usage limit for this file-system. */ 140 if (args->ta_size_max < PAGE_SIZE) { 141 memlimit = UINT64_MAX; 142 set_memlimit = false; 143 } else { 144 memlimit = args->ta_size_max; 145 set_memlimit = true; 146 } 147 KASSERT(memlimit > 0); 148 149 if (args->ta_nodes_max <= 3) { 150 nodes = 3 + (memlimit / 1024); 151 set_nodes = false; 152 } else { 153 nodes = args->ta_nodes_max; 154 set_nodes = true; 155 } 156 nodes = MIN(nodes, INT_MAX); 157 KASSERT(nodes >= 3); 158 159 if (mp->mnt_flag & MNT_UPDATE) { 160 tmp = VFS_TO_TMPFS(mp); 161 if (set_nodes && nodes < tmp->tm_nodes_cnt) 162 return EBUSY; 163 if (set_memlimit) { 164 if ((error = tmpfs_mntmem_set(tmp, memlimit)) != 0) 165 return error; 166 } 167 if (set_nodes) 168 tmp->tm_nodes_max = nodes; 169 root = tmp->tm_root; 170 root->tn_uid = args->ta_root_uid; 171 root->tn_gid = args->ta_root_gid; 172 root->tn_mode = args->ta_root_mode; 173 return 0; 174 } 175 176 /* Allocate the tmpfs mount structure and fill it. */ 177 tmp = kmem_zalloc(sizeof(tmpfs_mount_t), KM_SLEEP); 178 if (tmp == NULL) 179 return ENOMEM; 180 181 tmp->tm_nodes_max = nodes; 182 tmp->tm_nodes_cnt = 0; 183 LIST_INIT(&tmp->tm_nodes); 184 185 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 186 tmpfs_mntmem_init(tmp, memlimit); 187 mp->mnt_data = tmp; 188 189 /* Allocate the root node. */ 190 vattr_null(&va); 191 va.va_type = VDIR; 192 va.va_mode = args->ta_root_mode & ALLPERMS; 193 va.va_uid = args->ta_root_uid; 194 va.va_gid = args->ta_root_gid; 195 error = vcache_new(mp, NULL, &va, NOCRED, &vp); 196 if (error) { 197 mp->mnt_data = NULL; 198 tmpfs_mntmem_destroy(tmp); 199 mutex_destroy(&tmp->tm_lock); 200 kmem_free(tmp, sizeof(*tmp)); 201 return error; 202 } 203 KASSERT(vp != NULL); 204 root = VP_TO_TMPFS_NODE(vp); 205 KASSERT(root != NULL); 206 207 /* 208 * Parent of the root inode is itself. Also, root inode has no 209 * directory entry (i.e. is never attached), thus hold an extra 210 * reference (link) for it. 211 */ 212 root->tn_links++; 213 root->tn_spec.tn_dir.tn_parent = root; 214 tmp->tm_root = root; 215 vrele(vp); 216 217 mp->mnt_flag |= MNT_LOCAL; 218 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN; 219 mp->mnt_fs_bshift = PAGE_SHIFT; 220 mp->mnt_dev_bshift = DEV_BSHIFT; 221 mp->mnt_iflag |= IMNT_MPSAFE | IMNT_CAN_RWTORO; 222 vfs_getnewfsid(mp); 223 224 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 225 mp->mnt_op->vfs_name, mp, curlwp); 226 if (error) { 227 (void)tmpfs_unmount(mp, MNT_FORCE); 228 } 229 return error; 230 } 231 232 int 233 tmpfs_start(struct mount *mp, int flags) 234 { 235 236 return 0; 237 } 238 239 int 240 tmpfs_unmount(struct mount *mp, int mntflags) 241 { 242 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 243 tmpfs_node_t *node, *cnode; 244 int error, flags = 0; 245 246 /* Handle forced unmounts. */ 247 if (mntflags & MNT_FORCE) 248 flags |= FORCECLOSE; 249 250 /* Finalize all pending I/O. */ 251 error = vflush(mp, NULL, flags); 252 if (error != 0) 253 return error; 254 255 /* 256 * First round, detach and destroy all directory entries. 257 * Also, clear the pointers to the vnodes - they are gone. 258 */ 259 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 260 tmpfs_dirent_t *de; 261 262 node->tn_vnode = NULL; 263 if (node->tn_type != VDIR) { 264 continue; 265 } 266 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) { 267 cnode = de->td_node; 268 if (cnode && cnode != TMPFS_NODE_WHITEOUT) { 269 cnode->tn_vnode = NULL; 270 } 271 tmpfs_dir_detach(node, de); 272 tmpfs_free_dirent(tmp, de); 273 } 274 /* Extra virtual entry (itself for the root). */ 275 node->tn_links--; 276 } 277 278 /* Release the reference on root (diagnostic). */ 279 node = tmp->tm_root; 280 node->tn_links--; 281 282 /* Second round, destroy all inodes. */ 283 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) { 284 tmpfs_free_node(tmp, node); 285 } 286 287 /* Throw away the tmpfs_mount structure. */ 288 tmpfs_mntmem_destroy(tmp); 289 mutex_destroy(&tmp->tm_lock); 290 kmem_free(tmp, sizeof(*tmp)); 291 mp->mnt_data = NULL; 292 293 return 0; 294 } 295 296 int 297 tmpfs_root(struct mount *mp, vnode_t **vpp) 298 { 299 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root; 300 int error; 301 302 error = vcache_get(mp, &node, sizeof(node), vpp); 303 if (error) 304 return error; 305 error = vn_lock(*vpp, LK_EXCLUSIVE); 306 if (error) { 307 vrele(*vpp); 308 *vpp = NULL; 309 return error; 310 } 311 312 return 0; 313 } 314 315 int 316 tmpfs_vget(struct mount *mp, ino_t ino, vnode_t **vpp) 317 { 318 319 return EOPNOTSUPP; 320 } 321 322 int 323 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, vnode_t **vpp) 324 { 325 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 326 tmpfs_node_t *node; 327 tmpfs_fid_t tfh; 328 int error; 329 330 if (fhp->fid_len != sizeof(tmpfs_fid_t)) { 331 return EINVAL; 332 } 333 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t)); 334 335 mutex_enter(&tmp->tm_lock); 336 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 337 if (node->tn_id == tfh.tf_id) { 338 /* Prevent this node from disappearing. */ 339 atomic_inc_32(&node->tn_holdcount); 340 break; 341 } 342 } 343 mutex_exit(&tmp->tm_lock); 344 if (node == NULL) 345 return ESTALE; 346 347 error = vcache_get(mp, &node, sizeof(node), vpp); 348 /* If this node has been reclaimed free it now. */ 349 if (atomic_dec_32_nv(&node->tn_holdcount) == TMPFS_NODE_RECLAIMED) { 350 KASSERT(error != 0); 351 tmpfs_free_node(tmp, node); 352 } 353 if (error) 354 return (error == ENOENT ? ESTALE : error); 355 error = vn_lock(*vpp, LK_EXCLUSIVE); 356 if (error) { 357 vrele(*vpp); 358 *vpp = NULL; 359 return error; 360 } 361 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) { 362 vput(*vpp); 363 *vpp = NULL; 364 return ESTALE; 365 } 366 367 return 0; 368 } 369 370 int 371 tmpfs_vptofh(vnode_t *vp, struct fid *fhp, size_t *fh_size) 372 { 373 tmpfs_fid_t tfh; 374 tmpfs_node_t *node; 375 376 if (*fh_size < sizeof(tmpfs_fid_t)) { 377 *fh_size = sizeof(tmpfs_fid_t); 378 return E2BIG; 379 } 380 *fh_size = sizeof(tmpfs_fid_t); 381 node = VP_TO_TMPFS_NODE(vp); 382 383 memset(&tfh, 0, sizeof(tfh)); 384 tfh.tf_len = sizeof(tmpfs_fid_t); 385 tfh.tf_gen = TMPFS_NODE_GEN(node); 386 tfh.tf_id = node->tn_id; 387 memcpy(fhp, &tfh, sizeof(tfh)); 388 389 return 0; 390 } 391 392 int 393 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 394 { 395 tmpfs_mount_t *tmp; 396 fsfilcnt_t freenodes; 397 size_t avail; 398 399 tmp = VFS_TO_TMPFS(mp); 400 401 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 402 403 mutex_enter(&tmp->tm_acc_lock); 404 avail = tmpfs_pages_avail(tmp); 405 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 406 sbp->f_bavail = sbp->f_bfree = avail; 407 sbp->f_bresvd = 0; 408 409 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 410 avail * PAGE_SIZE / sizeof(tmpfs_node_t)); 411 412 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 413 sbp->f_favail = sbp->f_ffree = freenodes; 414 sbp->f_fresvd = 0; 415 mutex_exit(&tmp->tm_acc_lock); 416 417 copy_statvfs_info(sbp, mp); 418 419 return 0; 420 } 421 422 int 423 tmpfs_sync(struct mount *mp, int waitfor, kauth_cred_t uc) 424 { 425 426 return 0; 427 } 428 429 int 430 tmpfs_snapshot(struct mount *mp, vnode_t *vp, struct timespec *ctime) 431 { 432 433 return EOPNOTSUPP; 434 } 435 436 /* 437 * tmpfs vfs operations. 438 */ 439 440 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 441 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 442 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 443 444 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 445 &tmpfs_fifoop_opv_desc, 446 &tmpfs_specop_opv_desc, 447 &tmpfs_vnodeop_opv_desc, 448 NULL, 449 }; 450 451 struct vfsops tmpfs_vfsops = { 452 .vfs_name = MOUNT_TMPFS, 453 .vfs_min_mount_data = sizeof (struct tmpfs_args), 454 .vfs_mount = tmpfs_mount, 455 .vfs_start = tmpfs_start, 456 .vfs_unmount = tmpfs_unmount, 457 .vfs_root = tmpfs_root, 458 .vfs_quotactl = (void *)eopnotsupp, 459 .vfs_statvfs = tmpfs_statvfs, 460 .vfs_sync = tmpfs_sync, 461 .vfs_vget = tmpfs_vget, 462 .vfs_loadvnode = tmpfs_loadvnode, 463 .vfs_newvnode = tmpfs_newvnode, 464 .vfs_fhtovp = tmpfs_fhtovp, 465 .vfs_vptofh = tmpfs_vptofh, 466 .vfs_init = tmpfs_init, 467 .vfs_done = tmpfs_done, 468 .vfs_snapshot = tmpfs_snapshot, 469 .vfs_extattrctl = vfs_stdextattrctl, 470 .vfs_suspendctl = (void *)eopnotsupp, 471 .vfs_renamelock_enter = genfs_renamelock_enter, 472 .vfs_renamelock_exit = genfs_renamelock_exit, 473 .vfs_fsync = (void *)eopnotsupp, 474 .vfs_opv_descs = tmpfs_vnodeopv_descs 475 }; 476 477 static int 478 tmpfs_modcmd(modcmd_t cmd, void *arg) 479 { 480 481 switch (cmd) { 482 case MODULE_CMD_INIT: 483 return vfs_attach(&tmpfs_vfsops); 484 case MODULE_CMD_FINI: 485 return vfs_detach(&tmpfs_vfsops); 486 default: 487 return ENOTTY; 488 } 489 } 490