1 /* $NetBSD: tmpfs_vfsops.c,v 1.31 2007/11/10 03:36:16 ad Exp $ */ 2 3 /* 4 * Copyright (c) 2005, 2006 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 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Efficient memory file system. 42 * 43 * tmpfs is a file system that uses NetBSD's virtual memory sub-system 44 * (the well-known UVM) to store file data and metadata in an efficient 45 * way. This means that it does not follow the structure of an on-disk 46 * file system because it simply does not need to. Instead, it uses 47 * memory-specific data structures and algorithms to automatically 48 * allocate and release resources. 49 */ 50 51 #include <sys/cdefs.h> 52 __KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.31 2007/11/10 03:36:16 ad Exp $"); 53 54 #include <sys/param.h> 55 #include <sys/types.h> 56 #include <sys/malloc.h> 57 #include <sys/mount.h> 58 #include <sys/stat.h> 59 #include <sys/systm.h> 60 #include <sys/vnode.h> 61 #include <sys/proc.h> 62 63 #include <fs/tmpfs/tmpfs.h> 64 65 MALLOC_JUSTDEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures"); 66 MALLOC_JUSTDEFINE(M_TMPFSTMP, "tmpfs temp", "tmpfs temporary structures"); 67 68 /* --------------------------------------------------------------------- */ 69 70 static int tmpfs_mount(struct mount *, const char *, void *, size_t *, 71 struct lwp *); 72 static int tmpfs_start(struct mount *, int, struct lwp *); 73 static int tmpfs_unmount(struct mount *, int, struct lwp *); 74 static int tmpfs_root(struct mount *, struct vnode **); 75 static int tmpfs_quotactl(struct mount *, int, uid_t, void *, 76 struct lwp *); 77 static int tmpfs_vget(struct mount *, ino_t, struct vnode **); 78 static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); 79 static int tmpfs_vptofh(struct vnode *, struct fid *, size_t *); 80 static int tmpfs_statvfs(struct mount *, struct statvfs *, struct lwp *); 81 static int tmpfs_sync(struct mount *, int, kauth_cred_t, struct lwp *); 82 static void tmpfs_init(void); 83 static void tmpfs_done(void); 84 static int tmpfs_snapshot(struct mount *, struct vnode *, 85 struct timespec *); 86 87 /* --------------------------------------------------------------------- */ 88 89 static int 90 tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len, 91 struct lwp *l) 92 { 93 int error; 94 ino_t nodes; 95 size_t pages; 96 struct tmpfs_mount *tmp; 97 struct tmpfs_node *root; 98 struct tmpfs_args *args = data; 99 100 if (*data_len < sizeof *args) 101 return EINVAL; 102 103 /* Handle retrieval of mount point arguments. */ 104 if (mp->mnt_flag & MNT_GETARGS) { 105 if (mp->mnt_data == NULL) 106 return EIO; 107 tmp = VFS_TO_TMPFS(mp); 108 109 args->ta_version = TMPFS_ARGS_VERSION; 110 args->ta_nodes_max = tmp->tm_nodes_max; 111 args->ta_size_max = tmp->tm_pages_max * PAGE_SIZE; 112 113 root = tmp->tm_root; 114 args->ta_root_uid = root->tn_uid; 115 args->ta_root_gid = root->tn_gid; 116 args->ta_root_mode = root->tn_mode; 117 118 *data_len = sizeof *args; 119 return 0; 120 } 121 122 if (mp->mnt_flag & MNT_UPDATE) { 123 /* XXX: There is no support yet to update file system 124 * settings. Should be added. */ 125 126 return EOPNOTSUPP; 127 } 128 129 if (args->ta_version != TMPFS_ARGS_VERSION) 130 return EINVAL; 131 132 /* Do not allow mounts if we do not have enough memory to preserve 133 * the minimum reserved pages. */ 134 if (tmpfs_mem_info(true) < TMPFS_PAGES_RESERVED) 135 return EINVAL; 136 137 /* Get the maximum number of memory pages this file system is 138 * allowed to use, based on the maximum size the user passed in 139 * the mount structure. A value of zero is treated as if the 140 * maximum available space was requested. */ 141 if (args->ta_size_max < PAGE_SIZE || args->ta_size_max >= SIZE_MAX) 142 pages = SIZE_MAX; 143 else 144 pages = args->ta_size_max / PAGE_SIZE + 145 (args->ta_size_max % PAGE_SIZE == 0 ? 0 : 1); 146 KASSERT(pages > 0); 147 148 if (args->ta_nodes_max <= 3) 149 nodes = 3 + pages * PAGE_SIZE / 1024; 150 else 151 nodes = args->ta_nodes_max; 152 KASSERT(nodes >= 3); 153 154 /* Allocate the tmpfs mount structure and fill it. */ 155 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount), 156 M_TMPFSMNT, M_WAITOK); 157 KASSERT(tmp != NULL); 158 159 tmp->tm_nodes_max = nodes; 160 tmp->tm_nodes_last = 2; 161 LIST_INIT(&tmp->tm_nodes_used); 162 LIST_INIT(&tmp->tm_nodes_avail); 163 164 tmp->tm_pages_max = pages; 165 tmp->tm_pages_used = 0; 166 tmpfs_pool_init(&tmp->tm_dirent_pool, sizeof(struct tmpfs_dirent), 167 "dirent", tmp); 168 tmpfs_pool_init(&tmp->tm_node_pool, sizeof(struct tmpfs_node), 169 "node", tmp); 170 tmpfs_str_pool_init(&tmp->tm_str_pool, tmp); 171 172 /* Allocate the root node. */ 173 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 174 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL, 175 VNOVAL, l->l_proc, &root); 176 KASSERT(error == 0 && root != NULL); 177 tmp->tm_root = root; 178 179 mp->mnt_data = tmp; 180 mp->mnt_flag |= MNT_LOCAL; 181 mp->mnt_stat.f_namemax = MAXNAMLEN; 182 mp->mnt_fs_bshift = PAGE_SHIFT; 183 mp->mnt_dev_bshift = DEV_BSHIFT; 184 vfs_getnewfsid(mp); 185 186 return set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 187 mp->mnt_op->vfs_name, mp, l); 188 } 189 190 /* --------------------------------------------------------------------- */ 191 192 static int 193 tmpfs_start(struct mount *mp, int flags, 194 struct lwp *l) 195 { 196 197 return 0; 198 } 199 200 /* --------------------------------------------------------------------- */ 201 202 /* ARGSUSED2 */ 203 static int 204 tmpfs_unmount(struct mount *mp, int mntflags, struct lwp *l) 205 { 206 int error; 207 int flags = 0; 208 struct tmpfs_mount *tmp; 209 struct tmpfs_node *node; 210 211 /* Handle forced unmounts. */ 212 if (mntflags & MNT_FORCE) 213 flags |= FORCECLOSE; 214 215 /* Finalize all pending I/O. */ 216 error = vflush(mp, NULL, flags); 217 if (error != 0) 218 return error; 219 220 tmp = VFS_TO_TMPFS(mp); 221 222 /* Free all associated data. The loop iterates over the linked list 223 * we have containing all used nodes. For each of them that is 224 * a directory, we free all its directory entries. Note that after 225 * freeing a node, it will automatically go to the available list, 226 * so we will later have to iterate over it to release its items. */ 227 node = LIST_FIRST(&tmp->tm_nodes_used); 228 while (node != NULL) { 229 struct tmpfs_node *next; 230 231 if (node->tn_type == VDIR) { 232 struct tmpfs_dirent *de; 233 234 de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); 235 while (de != NULL) { 236 struct tmpfs_dirent *nde; 237 238 nde = TAILQ_NEXT(de, td_entries); 239 KASSERT(de->td_node->tn_vnode == NULL); 240 tmpfs_free_dirent(tmp, de, false); 241 de = nde; 242 node->tn_size -= sizeof(struct tmpfs_dirent); 243 } 244 } 245 246 next = LIST_NEXT(node, tn_entries); 247 tmpfs_free_node(tmp, node); 248 node = next; 249 } 250 node = LIST_FIRST(&tmp->tm_nodes_avail); 251 while (node != NULL) { 252 struct tmpfs_node *next; 253 254 next = LIST_NEXT(node, tn_entries); 255 LIST_REMOVE(node, tn_entries); 256 TMPFS_POOL_PUT(&tmp->tm_node_pool, node); 257 node = next; 258 } 259 260 tmpfs_pool_destroy(&tmp->tm_dirent_pool); 261 tmpfs_pool_destroy(&tmp->tm_node_pool); 262 tmpfs_str_pool_destroy(&tmp->tm_str_pool); 263 264 KASSERT(tmp->tm_pages_used == 0); 265 266 /* Throw away the tmpfs_mount structure. */ 267 free(mp->mnt_data, M_TMPFSMNT); 268 mp->mnt_data = NULL; 269 270 return 0; 271 } 272 273 /* --------------------------------------------------------------------- */ 274 275 static int 276 tmpfs_root(struct mount *mp, struct vnode **vpp) 277 { 278 279 return tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp); 280 } 281 282 /* --------------------------------------------------------------------- */ 283 284 static int 285 tmpfs_quotactl(struct mount *mp, int cmd, uid_t uid, 286 void *arg, struct lwp *l) 287 { 288 289 printf("tmpfs_quotactl called; need for it unknown yet\n"); 290 return EOPNOTSUPP; 291 } 292 293 /* --------------------------------------------------------------------- */ 294 295 static int 296 tmpfs_vget(struct mount *mp, ino_t ino, 297 struct vnode **vpp) 298 { 299 300 printf("tmpfs_vget called; need for it unknown yet\n"); 301 return EOPNOTSUPP; 302 } 303 304 /* --------------------------------------------------------------------- */ 305 306 static int 307 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp) 308 { 309 bool found; 310 struct tmpfs_fid tfh; 311 struct tmpfs_mount *tmp; 312 struct tmpfs_node *node; 313 314 tmp = VFS_TO_TMPFS(mp); 315 316 if (fhp->fid_len != sizeof(struct tmpfs_fid)) 317 return EINVAL; 318 319 memcpy(&tfh, fhp, sizeof(struct tmpfs_fid)); 320 321 if (tfh.tf_id >= tmp->tm_nodes_max) 322 return EINVAL; 323 324 found = false; 325 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) { 326 if (node->tn_id == tfh.tf_id && 327 node->tn_gen == tfh.tf_gen) { 328 found = true; 329 break; 330 } 331 } 332 333 return found ? tmpfs_alloc_vp(mp, node, vpp) : EINVAL; 334 } 335 336 /* --------------------------------------------------------------------- */ 337 338 static int 339 tmpfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 340 { 341 struct tmpfs_fid tfh; 342 struct tmpfs_node *node; 343 344 if (*fh_size < sizeof(struct tmpfs_fid)) { 345 *fh_size = sizeof(struct tmpfs_fid); 346 return E2BIG; 347 } 348 *fh_size = sizeof(struct tmpfs_fid); 349 node = VP_TO_TMPFS_NODE(vp); 350 351 memset(&tfh, 0, sizeof(tfh)); 352 tfh.tf_len = sizeof(struct tmpfs_fid); 353 tfh.tf_gen = node->tn_gen; 354 tfh.tf_id = node->tn_id; 355 memcpy(fhp, &tfh, sizeof(tfh)); 356 357 return 0; 358 } 359 360 /* --------------------------------------------------------------------- */ 361 362 /* ARGSUSED2 */ 363 static int 364 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp, struct lwp *l) 365 { 366 fsfilcnt_t freenodes, usednodes; 367 struct tmpfs_mount *tmp; 368 struct tmpfs_node *dummy; 369 370 tmp = VFS_TO_TMPFS(mp); 371 372 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 373 374 sbp->f_blocks = TMPFS_PAGES_MAX(tmp); 375 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp); 376 sbp->f_bresvd = 0; 377 378 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_last, 379 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node)); 380 LIST_FOREACH(dummy, &tmp->tm_nodes_avail, tn_entries) 381 freenodes++; 382 383 usednodes = 0; 384 LIST_FOREACH(dummy, &tmp->tm_nodes_used, tn_entries) 385 usednodes++; 386 387 sbp->f_files = freenodes + usednodes; 388 sbp->f_favail = sbp->f_ffree = freenodes; 389 sbp->f_fresvd = 0; 390 391 copy_statvfs_info(sbp, mp); 392 393 return 0; 394 } 395 396 /* --------------------------------------------------------------------- */ 397 398 /* ARGSUSED0 */ 399 static int 400 tmpfs_sync(struct mount *mp, int waitfor, 401 kauth_cred_t uc, struct lwp *l) 402 { 403 404 return 0; 405 } 406 407 /* --------------------------------------------------------------------- */ 408 409 static void 410 tmpfs_init(void) 411 { 412 413 malloc_type_attach(M_TMPFSMNT); 414 malloc_type_attach(M_TMPFSTMP); 415 } 416 417 /* --------------------------------------------------------------------- */ 418 419 static void 420 tmpfs_done(void) 421 { 422 423 malloc_type_detach(M_TMPFSTMP); 424 malloc_type_detach(M_TMPFSMNT); 425 } 426 427 /* --------------------------------------------------------------------- */ 428 429 static int 430 tmpfs_snapshot(struct mount *mp, struct vnode *vp, 431 struct timespec *ctime) 432 { 433 434 return EOPNOTSUPP; 435 } 436 437 /* --------------------------------------------------------------------- */ 438 439 /* 440 * tmpfs vfs operations. 441 */ 442 443 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 444 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 445 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 446 447 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 448 &tmpfs_fifoop_opv_desc, 449 &tmpfs_specop_opv_desc, 450 &tmpfs_vnodeop_opv_desc, 451 NULL, 452 }; 453 454 struct vfsops tmpfs_vfsops = { 455 MOUNT_TMPFS, /* vfs_name */ 456 sizeof (struct tmpfs_args), 457 tmpfs_mount, /* vfs_mount */ 458 tmpfs_start, /* vfs_start */ 459 tmpfs_unmount, /* vfs_unmount */ 460 tmpfs_root, /* vfs_root */ 461 tmpfs_quotactl, /* vfs_quotactl */ 462 tmpfs_statvfs, /* vfs_statvfs */ 463 tmpfs_sync, /* vfs_sync */ 464 tmpfs_vget, /* vfs_vget */ 465 tmpfs_fhtovp, /* vfs_fhtovp */ 466 tmpfs_vptofh, /* vfs_vptofh */ 467 tmpfs_init, /* vfs_init */ 468 NULL, /* vfs_reinit */ 469 tmpfs_done, /* vfs_done */ 470 NULL, /* vfs_mountroot */ 471 tmpfs_snapshot, /* vfs_snapshot */ 472 vfs_stdextattrctl, /* vfs_extattrctl */ 473 (void *)eopnotsupp, /* vfs_suspendctl */ 474 tmpfs_vnodeopv_descs, 475 0, /* vfs_refcount */ 476 { NULL, NULL }, 477 }; 478 VFS_ATTACH(tmpfs_vfsops); 479