1 /* $NetBSD: tmpfs_vfsops.c,v 1.63 2014/06/10 16:10:59 martin 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 1.63 2014/06/10 16:10:59 martin Exp $"); 46 47 #include <sys/param.h> 48 #include <sys/types.h> 49 #include <sys/kmem.h> 50 #include <sys/mount.h> 51 #include <sys/stat.h> 52 #include <sys/systm.h> 53 #include <sys/vnode.h> 54 #include <sys/module.h> 55 56 #include <miscfs/genfs/genfs.h> 57 #include <fs/tmpfs/tmpfs.h> 58 #include <fs/tmpfs/tmpfs_args.h> 59 60 MODULE(MODULE_CLASS_VFS, tmpfs, NULL); 61 62 struct pool tmpfs_dirent_pool; 63 struct pool tmpfs_node_pool; 64 65 static int tmpfs_mount(struct mount *, const char *, void *, size_t *); 66 static int tmpfs_start(struct mount *, int); 67 static int tmpfs_unmount(struct mount *, int); 68 static int tmpfs_root(struct mount *, vnode_t **); 69 static int tmpfs_vget(struct mount *, ino_t, vnode_t **); 70 static int tmpfs_fhtovp(struct mount *, struct fid *, vnode_t **); 71 static int tmpfs_vptofh(struct vnode *, struct fid *, size_t *); 72 static int tmpfs_statvfs(struct mount *, struct statvfs *); 73 static int tmpfs_sync(struct mount *, int, kauth_cred_t); 74 static void tmpfs_init(void); 75 static void tmpfs_done(void); 76 static int tmpfs_snapshot(struct mount *, vnode_t *, struct timespec *); 77 78 static void 79 tmpfs_init(void) 80 { 81 82 pool_init(&tmpfs_dirent_pool, sizeof(tmpfs_dirent_t), 0, 0, 0, 83 "tmpfs_dirent", &pool_allocator_nointr, IPL_NONE); 84 pool_init(&tmpfs_node_pool, sizeof(tmpfs_node_t), 0, 0, 0, 85 "tmpfs_node", &pool_allocator_nointr, IPL_NONE); 86 } 87 88 static void 89 tmpfs_done(void) 90 { 91 92 pool_destroy(&tmpfs_dirent_pool); 93 pool_destroy(&tmpfs_node_pool); 94 } 95 96 static int 97 tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 98 { 99 struct tmpfs_args *args = data; 100 tmpfs_mount_t *tmp; 101 tmpfs_node_t *root; 102 uint64_t memlimit; 103 ino_t nodes; 104 int error; 105 106 if (args == NULL) 107 return EINVAL; 108 109 /* Validate the version. */ 110 if (*data_len < sizeof(*args) || 111 args->ta_version != TMPFS_ARGS_VERSION) 112 return EINVAL; 113 114 /* Handle retrieval of mount point arguments. */ 115 if (mp->mnt_flag & MNT_GETARGS) { 116 if (mp->mnt_data == NULL) 117 return EIO; 118 tmp = VFS_TO_TMPFS(mp); 119 120 args->ta_version = TMPFS_ARGS_VERSION; 121 args->ta_nodes_max = tmp->tm_nodes_max; 122 args->ta_size_max = tmp->tm_mem_limit; 123 124 root = tmp->tm_root; 125 args->ta_root_uid = root->tn_uid; 126 args->ta_root_gid = root->tn_gid; 127 args->ta_root_mode = root->tn_mode; 128 129 *data_len = sizeof(*args); 130 return 0; 131 } 132 133 134 /* Prohibit mounts if there is not enough memory. */ 135 if (tmpfs_mem_info(true) < uvmexp.freetarg) 136 return EINVAL; 137 138 /* Check for invalid uid and gid arguments */ 139 if (args->ta_root_uid == VNOVAL || args->ta_root_gid == VNOVAL) 140 return EINVAL; 141 142 /* This can never happen? */ 143 if ((args->ta_root_mode & ALLPERMS) == VNOVAL) 144 return EINVAL; 145 146 /* Get the memory usage limit for this file-system. */ 147 if (args->ta_size_max < PAGE_SIZE) { 148 memlimit = UINT64_MAX; 149 } else { 150 memlimit = args->ta_size_max; 151 } 152 KASSERT(memlimit > 0); 153 154 if (args->ta_nodes_max <= 3) { 155 nodes = 3 + (memlimit / 1024); 156 } else { 157 nodes = args->ta_nodes_max; 158 } 159 nodes = MIN(nodes, INT_MAX); 160 KASSERT(nodes >= 3); 161 162 if (mp->mnt_flag & MNT_UPDATE) { 163 tmp = VFS_TO_TMPFS(mp); 164 if (nodes < tmp->tm_nodes_cnt) 165 return EBUSY; 166 if ((error = tmpfs_mntmem_set(tmp, memlimit)) != 0) 167 return error; 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); 187 188 /* Allocate the root node. */ 189 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 190 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, 191 VNOVAL, &root); 192 KASSERT(error == 0 && root != NULL); 193 194 /* 195 * Parent of the root inode is itself. Also, root inode has no 196 * directory entry (i.e. is never attached), thus hold an extra 197 * reference (link) for it. 198 */ 199 root->tn_links++; 200 root->tn_spec.tn_dir.tn_parent = root; 201 tmp->tm_root = root; 202 203 mp->mnt_data = tmp; 204 mp->mnt_flag |= MNT_LOCAL; 205 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN; 206 mp->mnt_fs_bshift = PAGE_SHIFT; 207 mp->mnt_dev_bshift = DEV_BSHIFT; 208 mp->mnt_iflag |= IMNT_MPSAFE; 209 vfs_getnewfsid(mp); 210 211 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 212 mp->mnt_op->vfs_name, mp, curlwp); 213 if (error) { 214 (void)tmpfs_unmount(mp, MNT_FORCE); 215 } 216 return error; 217 } 218 219 static int 220 tmpfs_start(struct mount *mp, int flags) 221 { 222 223 return 0; 224 } 225 226 static int 227 tmpfs_unmount(struct mount *mp, int mntflags) 228 { 229 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 230 tmpfs_node_t *node, *cnode; 231 int error, flags = 0; 232 233 /* Handle forced unmounts. */ 234 if (mntflags & MNT_FORCE) 235 flags |= FORCECLOSE; 236 237 /* Finalize all pending I/O. */ 238 error = vflush(mp, NULL, flags); 239 if (error != 0) 240 return error; 241 242 /* 243 * First round, detach and destroy all directory entries. 244 * Also, clear the pointers to the vnodes - they are gone. 245 */ 246 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 247 tmpfs_dirent_t *de; 248 249 node->tn_vnode = NULL; 250 if (node->tn_type != VDIR) { 251 continue; 252 } 253 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) { 254 cnode = de->td_node; 255 if (cnode && cnode != TMPFS_NODE_WHITEOUT) { 256 cnode->tn_vnode = NULL; 257 } 258 tmpfs_dir_detach(node, de); 259 tmpfs_free_dirent(tmp, de); 260 } 261 /* Extra virtual entry (itself for the root). */ 262 node->tn_links--; 263 } 264 265 /* Release the reference on root (diagnostic). */ 266 node = tmp->tm_root; 267 node->tn_links--; 268 269 /* Second round, destroy all inodes. */ 270 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) { 271 tmpfs_free_node(tmp, node); 272 } 273 274 /* Throw away the tmpfs_mount structure. */ 275 tmpfs_mntmem_destroy(tmp); 276 mutex_destroy(&tmp->tm_lock); 277 kmem_free(tmp, sizeof(*tmp)); 278 mp->mnt_data = NULL; 279 280 return 0; 281 } 282 283 static int 284 tmpfs_root(struct mount *mp, vnode_t **vpp) 285 { 286 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root; 287 288 mutex_enter(&node->tn_vlock); 289 return tmpfs_vnode_get(mp, node, vpp); 290 } 291 292 static int 293 tmpfs_vget(struct mount *mp, ino_t ino, vnode_t **vpp) 294 { 295 296 return EOPNOTSUPP; 297 } 298 299 static int 300 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, vnode_t **vpp) 301 { 302 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 303 tmpfs_node_t *node; 304 tmpfs_fid_t tfh; 305 int error; 306 307 if (fhp->fid_len != sizeof(tmpfs_fid_t)) { 308 return EINVAL; 309 } 310 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t)); 311 312 mutex_enter(&tmp->tm_lock); 313 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 314 if (node->tn_id == tfh.tf_id) { 315 mutex_enter(&node->tn_vlock); 316 break; 317 } 318 } 319 mutex_exit(&tmp->tm_lock); 320 321 if (node == NULL) 322 return ESTALE; 323 /* Will release the tn_vlock. */ 324 if ((error = tmpfs_vnode_get(mp, node, vpp)) != 0) 325 return error; 326 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) { 327 vput(*vpp); 328 *vpp = NULL; 329 return ESTALE; 330 } 331 332 return 0; 333 } 334 335 static int 336 tmpfs_vptofh(vnode_t *vp, struct fid *fhp, size_t *fh_size) 337 { 338 tmpfs_fid_t tfh; 339 tmpfs_node_t *node; 340 341 if (*fh_size < sizeof(tmpfs_fid_t)) { 342 *fh_size = sizeof(tmpfs_fid_t); 343 return E2BIG; 344 } 345 *fh_size = sizeof(tmpfs_fid_t); 346 node = VP_TO_TMPFS_NODE(vp); 347 348 memset(&tfh, 0, sizeof(tfh)); 349 tfh.tf_len = sizeof(tmpfs_fid_t); 350 tfh.tf_gen = TMPFS_NODE_GEN(node); 351 tfh.tf_id = node->tn_id; 352 memcpy(fhp, &tfh, sizeof(tfh)); 353 354 return 0; 355 } 356 357 static int 358 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 359 { 360 tmpfs_mount_t *tmp; 361 fsfilcnt_t freenodes; 362 size_t avail; 363 364 tmp = VFS_TO_TMPFS(mp); 365 366 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 367 368 mutex_enter(&tmp->tm_acc_lock); 369 avail = tmpfs_pages_avail(tmp); 370 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 371 sbp->f_bavail = sbp->f_bfree = avail; 372 sbp->f_bresvd = 0; 373 374 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 375 avail * PAGE_SIZE / sizeof(tmpfs_node_t)); 376 377 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 378 sbp->f_favail = sbp->f_ffree = freenodes; 379 sbp->f_fresvd = 0; 380 mutex_exit(&tmp->tm_acc_lock); 381 382 copy_statvfs_info(sbp, mp); 383 384 return 0; 385 } 386 387 static int 388 tmpfs_sync(struct mount *mp, int waitfor, kauth_cred_t uc) 389 { 390 391 return 0; 392 } 393 394 static int 395 tmpfs_snapshot(struct mount *mp, vnode_t *vp, struct timespec *ctime) 396 { 397 398 return EOPNOTSUPP; 399 } 400 401 /* 402 * tmpfs vfs operations. 403 */ 404 405 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 406 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 407 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 408 409 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 410 &tmpfs_fifoop_opv_desc, 411 &tmpfs_specop_opv_desc, 412 &tmpfs_vnodeop_opv_desc, 413 NULL, 414 }; 415 416 struct vfsops tmpfs_vfsops = { 417 .vfs_name = MOUNT_TMPFS, 418 .vfs_min_mount_data = sizeof (struct tmpfs_args), 419 .vfs_mount = tmpfs_mount, 420 .vfs_start = tmpfs_start, 421 .vfs_unmount = tmpfs_unmount, 422 .vfs_root = tmpfs_root, 423 .vfs_quotactl = (void *)eopnotsupp, 424 .vfs_statvfs = tmpfs_statvfs, 425 .vfs_sync = tmpfs_sync, 426 .vfs_vget = tmpfs_vget, 427 .vfs_fhtovp = tmpfs_fhtovp, 428 .vfs_vptofh = tmpfs_vptofh, 429 .vfs_init = tmpfs_init, 430 .vfs_done = tmpfs_done, 431 .vfs_snapshot = tmpfs_snapshot, 432 .vfs_extattrctl = vfs_stdextattrctl, 433 .vfs_suspendctl = (void *)eopnotsupp, 434 .vfs_renamelock_enter = genfs_renamelock_enter, 435 .vfs_renamelock_exit = genfs_renamelock_exit, 436 .vfs_fsync = (void *)eopnotsupp, 437 .vfs_opv_descs = tmpfs_vnodeopv_descs 438 }; 439 440 static int 441 tmpfs_modcmd(modcmd_t cmd, void *arg) 442 { 443 444 switch (cmd) { 445 case MODULE_CMD_INIT: 446 return vfs_attach(&tmpfs_vfsops); 447 case MODULE_CMD_FINI: 448 return vfs_detach(&tmpfs_vfsops); 449 default: 450 return ENOTTY; 451 } 452 } 453