1 /* $NetBSD: tmpfs_vfsops.c,v 1.61 2014/04/30 01:59:30 christos 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 1.61 2014/04/30 01:59:30 christos 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) < TMPFS_PAGES_RESERVED) 136 return EINVAL; 137 138 /* Get the memory usage limit for this file-system. */ 139 if (args->ta_size_max < PAGE_SIZE) { 140 memlimit = UINT64_MAX; 141 } else { 142 memlimit = args->ta_size_max; 143 } 144 KASSERT(memlimit > 0); 145 146 if (args->ta_nodes_max <= 3) { 147 nodes = 3 + (memlimit / 1024); 148 } else { 149 nodes = args->ta_nodes_max; 150 } 151 nodes = MIN(nodes, INT_MAX); 152 KASSERT(nodes >= 3); 153 154 if (mp->mnt_flag & MNT_UPDATE) { 155 tmp = VFS_TO_TMPFS(mp); 156 if (nodes < tmp->tm_nodes_cnt) 157 return EBUSY; 158 if ((error = tmpfs_mntmem_set(tmp, memlimit)) != 0) 159 return error; 160 tmp->tm_nodes_max = nodes; 161 root = tmp->tm_root; 162 root->tn_uid = args->ta_root_uid; 163 root->tn_gid = args->ta_root_gid; 164 root->tn_mode = args->ta_root_mode; 165 return 0; 166 } 167 168 /* Allocate the tmpfs mount structure and fill it. */ 169 tmp = kmem_zalloc(sizeof(tmpfs_mount_t), KM_SLEEP); 170 if (tmp == NULL) 171 return ENOMEM; 172 173 tmp->tm_nodes_max = nodes; 174 tmp->tm_nodes_cnt = 0; 175 LIST_INIT(&tmp->tm_nodes); 176 177 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 178 tmpfs_mntmem_init(tmp, memlimit); 179 180 /* Allocate the root node. */ 181 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 182 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, 183 VNOVAL, &root); 184 KASSERT(error == 0 && root != NULL); 185 186 /* 187 * Parent of the root inode is itself. Also, root inode has no 188 * directory entry (i.e. is never attached), thus hold an extra 189 * reference (link) for it. 190 */ 191 root->tn_links++; 192 root->tn_spec.tn_dir.tn_parent = root; 193 tmp->tm_root = root; 194 195 mp->mnt_data = tmp; 196 mp->mnt_flag |= MNT_LOCAL; 197 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN; 198 mp->mnt_fs_bshift = PAGE_SHIFT; 199 mp->mnt_dev_bshift = DEV_BSHIFT; 200 mp->mnt_iflag |= IMNT_MPSAFE; 201 vfs_getnewfsid(mp); 202 203 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 204 mp->mnt_op->vfs_name, mp, curlwp); 205 if (error) { 206 (void)tmpfs_unmount(mp, MNT_FORCE); 207 } 208 return error; 209 } 210 211 static int 212 tmpfs_start(struct mount *mp, int flags) 213 { 214 215 return 0; 216 } 217 218 static int 219 tmpfs_unmount(struct mount *mp, int mntflags) 220 { 221 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 222 tmpfs_node_t *node, *cnode; 223 int error, flags = 0; 224 225 /* Handle forced unmounts. */ 226 if (mntflags & MNT_FORCE) 227 flags |= FORCECLOSE; 228 229 /* Finalize all pending I/O. */ 230 error = vflush(mp, NULL, flags); 231 if (error != 0) 232 return error; 233 234 /* 235 * First round, detach and destroy all directory entries. 236 * Also, clear the pointers to the vnodes - they are gone. 237 */ 238 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 239 tmpfs_dirent_t *de; 240 241 node->tn_vnode = NULL; 242 if (node->tn_type != VDIR) { 243 continue; 244 } 245 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) { 246 cnode = de->td_node; 247 if (cnode && cnode != TMPFS_NODE_WHITEOUT) { 248 cnode->tn_vnode = NULL; 249 } 250 tmpfs_dir_detach(node, de); 251 tmpfs_free_dirent(tmp, de); 252 } 253 /* Extra virtual entry (itself for the root). */ 254 node->tn_links--; 255 } 256 257 /* Release the reference on root (diagnostic). */ 258 node = tmp->tm_root; 259 node->tn_links--; 260 261 /* Second round, destroy all inodes. */ 262 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) { 263 tmpfs_free_node(tmp, node); 264 } 265 266 /* Throw away the tmpfs_mount structure. */ 267 tmpfs_mntmem_destroy(tmp); 268 mutex_destroy(&tmp->tm_lock); 269 kmem_free(tmp, sizeof(*tmp)); 270 mp->mnt_data = NULL; 271 272 return 0; 273 } 274 275 static int 276 tmpfs_root(struct mount *mp, vnode_t **vpp) 277 { 278 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root; 279 280 mutex_enter(&node->tn_vlock); 281 return tmpfs_vnode_get(mp, node, vpp); 282 } 283 284 static int 285 tmpfs_vget(struct mount *mp, ino_t ino, vnode_t **vpp) 286 { 287 288 return EOPNOTSUPP; 289 } 290 291 static int 292 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, vnode_t **vpp) 293 { 294 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 295 tmpfs_node_t *node; 296 tmpfs_fid_t tfh; 297 int error; 298 299 if (fhp->fid_len != sizeof(tmpfs_fid_t)) { 300 return EINVAL; 301 } 302 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t)); 303 304 mutex_enter(&tmp->tm_lock); 305 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 306 if (node->tn_id == tfh.tf_id) { 307 mutex_enter(&node->tn_vlock); 308 break; 309 } 310 } 311 mutex_exit(&tmp->tm_lock); 312 313 if (node == NULL) 314 return ESTALE; 315 /* Will release the tn_vlock. */ 316 if ((error = tmpfs_vnode_get(mp, node, vpp)) != 0) 317 return error; 318 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) { 319 vput(*vpp); 320 *vpp = NULL; 321 return ESTALE; 322 } 323 324 return 0; 325 } 326 327 static int 328 tmpfs_vptofh(vnode_t *vp, struct fid *fhp, size_t *fh_size) 329 { 330 tmpfs_fid_t tfh; 331 tmpfs_node_t *node; 332 333 if (*fh_size < sizeof(tmpfs_fid_t)) { 334 *fh_size = sizeof(tmpfs_fid_t); 335 return E2BIG; 336 } 337 *fh_size = sizeof(tmpfs_fid_t); 338 node = VP_TO_TMPFS_NODE(vp); 339 340 memset(&tfh, 0, sizeof(tfh)); 341 tfh.tf_len = sizeof(tmpfs_fid_t); 342 tfh.tf_gen = TMPFS_NODE_GEN(node); 343 tfh.tf_id = node->tn_id; 344 memcpy(fhp, &tfh, sizeof(tfh)); 345 346 return 0; 347 } 348 349 static int 350 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 351 { 352 tmpfs_mount_t *tmp; 353 fsfilcnt_t freenodes; 354 size_t avail; 355 356 tmp = VFS_TO_TMPFS(mp); 357 358 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 359 360 mutex_enter(&tmp->tm_acc_lock); 361 avail = tmpfs_pages_avail(tmp); 362 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 363 sbp->f_bavail = sbp->f_bfree = avail; 364 sbp->f_bresvd = 0; 365 366 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 367 avail * PAGE_SIZE / sizeof(tmpfs_node_t)); 368 369 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 370 sbp->f_favail = sbp->f_ffree = freenodes; 371 sbp->f_fresvd = 0; 372 mutex_exit(&tmp->tm_acc_lock); 373 374 copy_statvfs_info(sbp, mp); 375 376 return 0; 377 } 378 379 static int 380 tmpfs_sync(struct mount *mp, int waitfor, kauth_cred_t uc) 381 { 382 383 return 0; 384 } 385 386 static int 387 tmpfs_snapshot(struct mount *mp, vnode_t *vp, struct timespec *ctime) 388 { 389 390 return EOPNOTSUPP; 391 } 392 393 /* 394 * tmpfs vfs operations. 395 */ 396 397 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 398 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 399 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 400 401 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 402 &tmpfs_fifoop_opv_desc, 403 &tmpfs_specop_opv_desc, 404 &tmpfs_vnodeop_opv_desc, 405 NULL, 406 }; 407 408 struct vfsops tmpfs_vfsops = { 409 .vfs_name = MOUNT_TMPFS, 410 .vfs_min_mount_data = sizeof (struct tmpfs_args), 411 .vfs_mount = tmpfs_mount, 412 .vfs_start = tmpfs_start, 413 .vfs_unmount = tmpfs_unmount, 414 .vfs_root = tmpfs_root, 415 .vfs_quotactl = (void *)eopnotsupp, 416 .vfs_statvfs = tmpfs_statvfs, 417 .vfs_sync = tmpfs_sync, 418 .vfs_vget = tmpfs_vget, 419 .vfs_fhtovp = tmpfs_fhtovp, 420 .vfs_vptofh = tmpfs_vptofh, 421 .vfs_init = tmpfs_init, 422 .vfs_done = tmpfs_done, 423 .vfs_snapshot = tmpfs_snapshot, 424 .vfs_extattrctl = vfs_stdextattrctl, 425 .vfs_suspendctl = (void *)eopnotsupp, 426 .vfs_renamelock_enter = genfs_renamelock_enter, 427 .vfs_renamelock_exit = genfs_renamelock_exit, 428 .vfs_fsync = (void *)eopnotsupp, 429 .vfs_opv_descs = tmpfs_vnodeopv_descs 430 }; 431 432 static int 433 tmpfs_modcmd(modcmd_t cmd, void *arg) 434 { 435 436 switch (cmd) { 437 case MODULE_CMD_INIT: 438 return vfs_attach(&tmpfs_vfsops); 439 case MODULE_CMD_FINI: 440 return vfs_detach(&tmpfs_vfsops); 441 default: 442 return ENOTTY; 443 } 444 } 445