1 /* $NetBSD: tmpfs_vfsops.c,v 1.39 2008/04/28 20:24:02 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 1.39 2008/04/28 20:24:02 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/proc.h> 55 56 #include <miscfs/genfs/genfs.h> 57 #include <fs/tmpfs/tmpfs.h> 58 59 /* --------------------------------------------------------------------- */ 60 61 static int tmpfs_mount(struct mount *, const char *, void *, size_t *); 62 static int tmpfs_start(struct mount *, int); 63 static int tmpfs_unmount(struct mount *, int); 64 static int tmpfs_root(struct mount *, struct vnode **); 65 static int tmpfs_vget(struct mount *, ino_t, struct vnode **); 66 static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); 67 static int tmpfs_vptofh(struct vnode *, struct fid *, size_t *); 68 static int tmpfs_statvfs(struct mount *, struct statvfs *); 69 static int tmpfs_sync(struct mount *, int, kauth_cred_t); 70 static void tmpfs_init(void); 71 static void tmpfs_done(void); 72 static int tmpfs_snapshot(struct mount *, struct vnode *, 73 struct timespec *); 74 75 /* --------------------------------------------------------------------- */ 76 77 static int 78 tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 79 { 80 struct lwp *l = curlwp; 81 int error; 82 ino_t nodes; 83 size_t pages; 84 struct tmpfs_mount *tmp; 85 struct tmpfs_node *root; 86 struct tmpfs_args *args = data; 87 88 if (*data_len < sizeof *args) 89 return EINVAL; 90 91 /* Handle retrieval of mount point arguments. */ 92 if (mp->mnt_flag & MNT_GETARGS) { 93 if (mp->mnt_data == NULL) 94 return EIO; 95 tmp = VFS_TO_TMPFS(mp); 96 97 args->ta_version = TMPFS_ARGS_VERSION; 98 args->ta_nodes_max = tmp->tm_nodes_max; 99 args->ta_size_max = tmp->tm_pages_max * PAGE_SIZE; 100 101 root = tmp->tm_root; 102 args->ta_root_uid = root->tn_uid; 103 args->ta_root_gid = root->tn_gid; 104 args->ta_root_mode = root->tn_mode; 105 106 *data_len = sizeof *args; 107 return 0; 108 } 109 110 if (mp->mnt_flag & MNT_UPDATE) { 111 /* XXX: There is no support yet to update file system 112 * settings. Should be added. */ 113 114 return EOPNOTSUPP; 115 } 116 117 if (args->ta_version != TMPFS_ARGS_VERSION) 118 return EINVAL; 119 120 /* Do not allow mounts if we do not have enough memory to preserve 121 * the minimum reserved pages. */ 122 if (tmpfs_mem_info(true) < TMPFS_PAGES_RESERVED) 123 return EINVAL; 124 125 /* Get the maximum number of memory pages this file system is 126 * allowed to use, based on the maximum size the user passed in 127 * the mount structure. A value of zero is treated as if the 128 * maximum available space was requested. */ 129 if (args->ta_size_max < PAGE_SIZE || args->ta_size_max >= SIZE_MAX) 130 pages = SIZE_MAX; 131 else 132 pages = args->ta_size_max / PAGE_SIZE + 133 (args->ta_size_max % PAGE_SIZE == 0 ? 0 : 1); 134 if (pages > INT_MAX) 135 pages = INT_MAX; 136 KASSERT(pages > 0); 137 138 if (args->ta_nodes_max <= 3) 139 nodes = 3 + pages * PAGE_SIZE / 1024; 140 else 141 nodes = args->ta_nodes_max; 142 if (nodes > INT_MAX) 143 nodes = INT_MAX; 144 KASSERT(nodes >= 3); 145 146 /* Allocate the tmpfs mount structure and fill it. */ 147 tmp = kmem_alloc(sizeof(struct tmpfs_mount), KM_SLEEP); 148 if (tmp == NULL) 149 return ENOMEM; 150 151 tmp->tm_nodes_max = nodes; 152 tmp->tm_nodes_cnt = 0; 153 LIST_INIT(&tmp->tm_nodes); 154 155 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 156 157 tmp->tm_pages_max = pages; 158 tmp->tm_pages_used = 0; 159 tmpfs_pool_init(&tmp->tm_dirent_pool, sizeof(struct tmpfs_dirent), 160 "dirent", tmp); 161 tmpfs_pool_init(&tmp->tm_node_pool, sizeof(struct tmpfs_node), 162 "node", tmp); 163 tmpfs_str_pool_init(&tmp->tm_str_pool, tmp); 164 165 /* Allocate the root node. */ 166 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 167 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL, 168 VNOVAL, &root); 169 KASSERT(error == 0 && root != NULL); 170 root->tn_links++; 171 tmp->tm_root = root; 172 173 mp->mnt_data = tmp; 174 mp->mnt_flag |= MNT_LOCAL; 175 mp->mnt_stat.f_namemax = MAXNAMLEN; 176 mp->mnt_fs_bshift = PAGE_SHIFT; 177 mp->mnt_dev_bshift = DEV_BSHIFT; 178 mp->mnt_iflag |= IMNT_MPSAFE; 179 vfs_getnewfsid(mp); 180 181 return set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 182 mp->mnt_op->vfs_name, mp, l); 183 } 184 185 /* --------------------------------------------------------------------- */ 186 187 static int 188 tmpfs_start(struct mount *mp, int flags) 189 { 190 191 return 0; 192 } 193 194 /* --------------------------------------------------------------------- */ 195 196 /* ARGSUSED2 */ 197 static int 198 tmpfs_unmount(struct mount *mp, int mntflags) 199 { 200 int error; 201 int flags = 0; 202 struct tmpfs_mount *tmp; 203 struct tmpfs_node *node; 204 205 /* Handle forced unmounts. */ 206 if (mntflags & MNT_FORCE) 207 flags |= FORCECLOSE; 208 209 /* Finalize all pending I/O. */ 210 error = vflush(mp, NULL, flags); 211 if (error != 0) 212 return error; 213 214 tmp = VFS_TO_TMPFS(mp); 215 216 /* Free all associated data. The loop iterates over the linked list 217 * we have containing all used nodes. For each of them that is 218 * a directory, we free all its directory entries. Note that after 219 * freeing a node, it will automatically go to the available list, 220 * so we will later have to iterate over it to release its items. */ 221 node = LIST_FIRST(&tmp->tm_nodes); 222 while (node != NULL) { 223 struct tmpfs_node *next; 224 225 if (node->tn_type == VDIR) { 226 struct tmpfs_dirent *de; 227 228 de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); 229 while (de != NULL) { 230 struct tmpfs_dirent *nde; 231 232 nde = TAILQ_NEXT(de, td_entries); 233 tmpfs_free_dirent(tmp, de, false); 234 de = nde; 235 node->tn_size -= sizeof(struct tmpfs_dirent); 236 } 237 } 238 239 next = LIST_NEXT(node, tn_entries); 240 tmpfs_free_node(tmp, node); 241 node = next; 242 } 243 244 tmpfs_pool_destroy(&tmp->tm_dirent_pool); 245 tmpfs_pool_destroy(&tmp->tm_node_pool); 246 tmpfs_str_pool_destroy(&tmp->tm_str_pool); 247 248 KASSERT(tmp->tm_pages_used == 0); 249 250 /* Throw away the tmpfs_mount structure. */ 251 mutex_destroy(&tmp->tm_lock); 252 kmem_free(tmp, sizeof(*tmp)); 253 mp->mnt_data = NULL; 254 255 return 0; 256 } 257 258 /* --------------------------------------------------------------------- */ 259 260 static int 261 tmpfs_root(struct mount *mp, struct vnode **vpp) 262 { 263 264 return tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp); 265 } 266 267 /* --------------------------------------------------------------------- */ 268 269 static int 270 tmpfs_vget(struct mount *mp, ino_t ino, 271 struct vnode **vpp) 272 { 273 274 printf("tmpfs_vget called; need for it unknown yet\n"); 275 return EOPNOTSUPP; 276 } 277 278 /* --------------------------------------------------------------------- */ 279 280 static int 281 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp) 282 { 283 bool found; 284 struct tmpfs_fid tfh; 285 struct tmpfs_mount *tmp; 286 struct tmpfs_node *node; 287 288 tmp = VFS_TO_TMPFS(mp); 289 290 if (fhp->fid_len != sizeof(struct tmpfs_fid)) 291 return EINVAL; 292 293 memcpy(&tfh, fhp, sizeof(struct tmpfs_fid)); 294 295 if (tfh.tf_id >= tmp->tm_nodes_max) 296 return EINVAL; 297 298 found = false; 299 mutex_enter(&tmp->tm_lock); 300 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 301 if (node->tn_id == tfh.tf_id && 302 node->tn_gen == tfh.tf_gen) { 303 found = true; 304 break; 305 } 306 } 307 mutex_exit(&tmp->tm_lock); 308 309 /* XXXAD nothing to prevent 'node' from being removed. */ 310 return found ? tmpfs_alloc_vp(mp, node, vpp) : EINVAL; 311 } 312 313 /* --------------------------------------------------------------------- */ 314 315 static int 316 tmpfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 317 { 318 struct tmpfs_fid tfh; 319 struct tmpfs_node *node; 320 321 if (*fh_size < sizeof(struct tmpfs_fid)) { 322 *fh_size = sizeof(struct tmpfs_fid); 323 return E2BIG; 324 } 325 *fh_size = sizeof(struct tmpfs_fid); 326 node = VP_TO_TMPFS_NODE(vp); 327 328 memset(&tfh, 0, sizeof(tfh)); 329 tfh.tf_len = sizeof(struct tmpfs_fid); 330 tfh.tf_gen = node->tn_gen; 331 tfh.tf_id = node->tn_id; 332 memcpy(fhp, &tfh, sizeof(tfh)); 333 334 return 0; 335 } 336 337 /* --------------------------------------------------------------------- */ 338 339 /* ARGSUSED2 */ 340 static int 341 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 342 { 343 fsfilcnt_t freenodes; 344 struct tmpfs_mount *tmp; 345 346 tmp = VFS_TO_TMPFS(mp); 347 348 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 349 350 sbp->f_blocks = TMPFS_PAGES_MAX(tmp); 351 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp); 352 sbp->f_bresvd = 0; 353 354 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 355 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node)); 356 357 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 358 sbp->f_favail = sbp->f_ffree = freenodes; 359 sbp->f_fresvd = 0; 360 361 copy_statvfs_info(sbp, mp); 362 363 return 0; 364 } 365 366 /* --------------------------------------------------------------------- */ 367 368 /* ARGSUSED0 */ 369 static int 370 tmpfs_sync(struct mount *mp, int waitfor, 371 kauth_cred_t uc) 372 { 373 374 return 0; 375 } 376 377 /* --------------------------------------------------------------------- */ 378 379 static void 380 tmpfs_init(void) 381 { 382 383 } 384 385 /* --------------------------------------------------------------------- */ 386 387 static void 388 tmpfs_done(void) 389 { 390 391 } 392 393 /* --------------------------------------------------------------------- */ 394 395 static int 396 tmpfs_snapshot(struct mount *mp, struct vnode *vp, 397 struct timespec *ctime) 398 { 399 400 return EOPNOTSUPP; 401 } 402 403 /* --------------------------------------------------------------------- */ 404 405 /* 406 * tmpfs vfs operations. 407 */ 408 409 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 410 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 411 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 412 413 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 414 &tmpfs_fifoop_opv_desc, 415 &tmpfs_specop_opv_desc, 416 &tmpfs_vnodeop_opv_desc, 417 NULL, 418 }; 419 420 struct vfsops tmpfs_vfsops = { 421 MOUNT_TMPFS, /* vfs_name */ 422 sizeof (struct tmpfs_args), 423 tmpfs_mount, /* vfs_mount */ 424 tmpfs_start, /* vfs_start */ 425 tmpfs_unmount, /* vfs_unmount */ 426 tmpfs_root, /* vfs_root */ 427 (void *)eopnotsupp, /* vfs_quotactl */ 428 tmpfs_statvfs, /* vfs_statvfs */ 429 tmpfs_sync, /* vfs_sync */ 430 tmpfs_vget, /* vfs_vget */ 431 tmpfs_fhtovp, /* vfs_fhtovp */ 432 tmpfs_vptofh, /* vfs_vptofh */ 433 tmpfs_init, /* vfs_init */ 434 NULL, /* vfs_reinit */ 435 tmpfs_done, /* vfs_done */ 436 NULL, /* vfs_mountroot */ 437 tmpfs_snapshot, /* vfs_snapshot */ 438 vfs_stdextattrctl, /* vfs_extattrctl */ 439 (void *)eopnotsupp, /* vfs_suspendctl */ 440 genfs_renamelock_enter, 441 genfs_renamelock_exit, 442 tmpfs_vnodeopv_descs, 443 0, /* vfs_refcount */ 444 { NULL, NULL }, 445 }; 446 VFS_ATTACH(tmpfs_vfsops); 447