1 /* $NetBSD: tmpfs_vfsops.c,v 1.47 2011/04/02 14:24:53 hannken 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 1.47 2011/04/02 14:24:53 hannken 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 #include <sys/module.h> 56 57 #include <miscfs/genfs/genfs.h> 58 #include <fs/tmpfs/tmpfs.h> 59 #include <fs/tmpfs/tmpfs_args.h> 60 61 MODULE(MODULE_CLASS_VFS, tmpfs, NULL); 62 63 /* --------------------------------------------------------------------- */ 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 *, struct vnode **); 69 static int tmpfs_vget(struct mount *, ino_t, struct vnode **); 70 static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); 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 *, struct vnode *, 77 struct timespec *); 78 79 /* --------------------------------------------------------------------- */ 80 81 static int 82 tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 83 { 84 struct tmpfs_mount *tmp; 85 struct tmpfs_node *root; 86 struct tmpfs_args *args = data; 87 uint64_t memlimit; 88 ino_t nodes; 89 int error; 90 91 if (*data_len < sizeof *args) 92 return EINVAL; 93 94 /* Handle retrieval of mount point arguments. */ 95 if (mp->mnt_flag & MNT_GETARGS) { 96 if (mp->mnt_data == NULL) 97 return EIO; 98 tmp = VFS_TO_TMPFS(mp); 99 100 args->ta_version = TMPFS_ARGS_VERSION; 101 args->ta_nodes_max = tmp->tm_nodes_max; 102 args->ta_size_max = tmp->tm_mem_limit; 103 104 root = tmp->tm_root; 105 args->ta_root_uid = root->tn_uid; 106 args->ta_root_gid = root->tn_gid; 107 args->ta_root_mode = root->tn_mode; 108 109 *data_len = sizeof(*args); 110 return 0; 111 } 112 113 if (mp->mnt_flag & MNT_UPDATE) { 114 /* XXX: There is no support yet to update file system 115 * settings. Should be added. */ 116 117 return EOPNOTSUPP; 118 } 119 120 if (args->ta_version != TMPFS_ARGS_VERSION) 121 return EINVAL; 122 123 /* Do not allow mounts if we do not have enough memory to preserve 124 * the minimum reserved pages. */ 125 if (tmpfs_mem_info(true) < TMPFS_PAGES_RESERVED) 126 return EINVAL; 127 128 /* Get the memory usage limit for this file-system. */ 129 if (args->ta_size_max < PAGE_SIZE) { 130 memlimit = UINT64_MAX; 131 } else { 132 memlimit = args->ta_size_max; 133 } 134 KASSERT(memlimit > 0); 135 136 if (args->ta_nodes_max <= 3) { 137 nodes = 3 + (memlimit / 1024); 138 } else { 139 nodes = args->ta_nodes_max; 140 } 141 nodes = MIN(nodes, INT_MAX); 142 KASSERT(nodes >= 3); 143 144 /* Allocate the tmpfs mount structure and fill it. */ 145 tmp = kmem_alloc(sizeof(struct tmpfs_mount), KM_SLEEP); 146 if (tmp == NULL) 147 return ENOMEM; 148 149 tmp->tm_nodes_max = nodes; 150 tmp->tm_nodes_cnt = 0; 151 LIST_INIT(&tmp->tm_nodes); 152 153 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 154 tmpfs_mntmem_init(tmp, memlimit); 155 156 /* Allocate the root node. */ 157 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 158 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL, 159 VNOVAL, &root); 160 KASSERT(error == 0 && root != NULL); 161 root->tn_links++; 162 tmp->tm_root = root; 163 164 mp->mnt_data = tmp; 165 mp->mnt_flag |= MNT_LOCAL; 166 mp->mnt_stat.f_namemax = MAXNAMLEN; 167 mp->mnt_fs_bshift = PAGE_SHIFT; 168 mp->mnt_dev_bshift = DEV_BSHIFT; 169 mp->mnt_iflag |= IMNT_MPSAFE; 170 vfs_getnewfsid(mp); 171 172 return set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 173 mp->mnt_op->vfs_name, mp, curlwp); 174 } 175 176 /* --------------------------------------------------------------------- */ 177 178 static int 179 tmpfs_start(struct mount *mp, int flags) 180 { 181 182 return 0; 183 } 184 185 /* --------------------------------------------------------------------- */ 186 187 /* ARGSUSED2 */ 188 static int 189 tmpfs_unmount(struct mount *mp, int mntflags) 190 { 191 int error; 192 int flags = 0; 193 struct tmpfs_mount *tmp; 194 struct tmpfs_node *node; 195 196 /* Handle forced unmounts. */ 197 if (mntflags & MNT_FORCE) 198 flags |= FORCECLOSE; 199 200 /* Finalize all pending I/O. */ 201 error = vflush(mp, NULL, flags); 202 if (error != 0) 203 return error; 204 205 tmp = VFS_TO_TMPFS(mp); 206 207 /* Free all associated data. The loop iterates over the linked list 208 * we have containing all used nodes. For each of them that is 209 * a directory, we free all its directory entries. Note that after 210 * freeing a node, it will automatically go to the available list, 211 * so we will later have to iterate over it to release its items. */ 212 node = LIST_FIRST(&tmp->tm_nodes); 213 while (node != NULL) { 214 struct tmpfs_node *next; 215 216 if (node->tn_type == VDIR) { 217 struct tmpfs_dirent *de; 218 219 de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); 220 while (de != NULL) { 221 struct tmpfs_dirent *nde; 222 223 nde = TAILQ_NEXT(de, td_entries); 224 tmpfs_free_dirent(tmp, de, false); 225 de = nde; 226 node->tn_size -= sizeof(struct tmpfs_dirent); 227 } 228 } 229 230 next = LIST_NEXT(node, tn_entries); 231 tmpfs_free_node(tmp, node); 232 node = next; 233 } 234 235 /* Throw away the tmpfs_mount structure. */ 236 tmpfs_mntmem_destroy(tmp); 237 mutex_destroy(&tmp->tm_lock); 238 kmem_free(tmp, sizeof(*tmp)); 239 mp->mnt_data = NULL; 240 241 return 0; 242 } 243 244 /* --------------------------------------------------------------------- */ 245 246 static int 247 tmpfs_root(struct mount *mp, struct vnode **vpp) 248 { 249 250 return tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp); 251 } 252 253 /* --------------------------------------------------------------------- */ 254 255 static int 256 tmpfs_vget(struct mount *mp, ino_t ino, 257 struct vnode **vpp) 258 { 259 260 printf("tmpfs_vget called; need for it unknown yet\n"); 261 return EOPNOTSUPP; 262 } 263 264 /* --------------------------------------------------------------------- */ 265 266 static int 267 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp) 268 { 269 bool found; 270 struct tmpfs_fid tfh; 271 struct tmpfs_mount *tmp; 272 struct tmpfs_node *node; 273 274 tmp = VFS_TO_TMPFS(mp); 275 276 if (fhp->fid_len != sizeof(struct tmpfs_fid)) 277 return EINVAL; 278 279 memcpy(&tfh, fhp, sizeof(struct tmpfs_fid)); 280 281 found = false; 282 mutex_enter(&tmp->tm_lock); 283 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 284 if (node->tn_id == tfh.tf_id && 285 node->tn_gen == tfh.tf_gen) { 286 found = true; 287 break; 288 } 289 } 290 mutex_exit(&tmp->tm_lock); 291 292 /* XXXAD nothing to prevent 'node' from being removed. */ 293 return found ? tmpfs_alloc_vp(mp, node, vpp) : ESTALE; 294 } 295 296 /* --------------------------------------------------------------------- */ 297 298 static int 299 tmpfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 300 { 301 struct tmpfs_fid tfh; 302 struct tmpfs_node *node; 303 304 if (*fh_size < sizeof(struct tmpfs_fid)) { 305 *fh_size = sizeof(struct tmpfs_fid); 306 return E2BIG; 307 } 308 *fh_size = sizeof(struct tmpfs_fid); 309 node = VP_TO_TMPFS_NODE(vp); 310 311 memset(&tfh, 0, sizeof(tfh)); 312 tfh.tf_len = sizeof(struct tmpfs_fid); 313 tfh.tf_gen = node->tn_gen; 314 tfh.tf_id = node->tn_id; 315 memcpy(fhp, &tfh, sizeof(tfh)); 316 317 return 0; 318 } 319 320 /* --------------------------------------------------------------------- */ 321 322 static int 323 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 324 { 325 struct tmpfs_mount *tmp; 326 fsfilcnt_t freenodes; 327 size_t avail; 328 329 tmp = VFS_TO_TMPFS(mp); 330 331 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 332 333 mutex_enter(&tmp->tm_acc_lock); 334 avail = tmpfs_pages_avail(tmp); 335 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 336 sbp->f_bavail = sbp->f_bfree = avail; 337 sbp->f_bresvd = 0; 338 339 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 340 avail * PAGE_SIZE / sizeof(struct tmpfs_node)); 341 342 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 343 sbp->f_favail = sbp->f_ffree = freenodes; 344 sbp->f_fresvd = 0; 345 mutex_exit(&tmp->tm_acc_lock); 346 347 copy_statvfs_info(sbp, mp); 348 349 return 0; 350 } 351 352 /* --------------------------------------------------------------------- */ 353 354 /* ARGSUSED0 */ 355 static int 356 tmpfs_sync(struct mount *mp, int waitfor, 357 kauth_cred_t uc) 358 { 359 360 return 0; 361 } 362 363 /* --------------------------------------------------------------------- */ 364 365 static void 366 tmpfs_init(void) 367 { 368 369 } 370 371 /* --------------------------------------------------------------------- */ 372 373 static void 374 tmpfs_done(void) 375 { 376 377 } 378 379 /* --------------------------------------------------------------------- */ 380 381 static int 382 tmpfs_snapshot(struct mount *mp, struct vnode *vp, 383 struct timespec *ctime) 384 { 385 386 return EOPNOTSUPP; 387 } 388 389 /* --------------------------------------------------------------------- */ 390 391 /* 392 * tmpfs vfs operations. 393 */ 394 395 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 396 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 397 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 398 399 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 400 &tmpfs_fifoop_opv_desc, 401 &tmpfs_specop_opv_desc, 402 &tmpfs_vnodeop_opv_desc, 403 NULL, 404 }; 405 406 struct vfsops tmpfs_vfsops = { 407 MOUNT_TMPFS, /* vfs_name */ 408 sizeof (struct tmpfs_args), 409 tmpfs_mount, /* vfs_mount */ 410 tmpfs_start, /* vfs_start */ 411 tmpfs_unmount, /* vfs_unmount */ 412 tmpfs_root, /* vfs_root */ 413 (void *)eopnotsupp, /* vfs_quotactl */ 414 tmpfs_statvfs, /* vfs_statvfs */ 415 tmpfs_sync, /* vfs_sync */ 416 tmpfs_vget, /* vfs_vget */ 417 tmpfs_fhtovp, /* vfs_fhtovp */ 418 tmpfs_vptofh, /* vfs_vptofh */ 419 tmpfs_init, /* vfs_init */ 420 NULL, /* vfs_reinit */ 421 tmpfs_done, /* vfs_done */ 422 NULL, /* vfs_mountroot */ 423 tmpfs_snapshot, /* vfs_snapshot */ 424 vfs_stdextattrctl, /* vfs_extattrctl */ 425 (void *)eopnotsupp, /* vfs_suspendctl */ 426 genfs_renamelock_enter, 427 genfs_renamelock_exit, 428 (void *)eopnotsupp, 429 tmpfs_vnodeopv_descs, 430 0, /* vfs_refcount */ 431 { NULL, NULL }, 432 }; 433 434 static int 435 tmpfs_modcmd(modcmd_t cmd, void *arg) 436 { 437 438 switch (cmd) { 439 case MODULE_CMD_INIT: 440 return vfs_attach(&tmpfs_vfsops); 441 case MODULE_CMD_FINI: 442 return vfs_detach(&tmpfs_vfsops); 443 default: 444 return ENOTTY; 445 } 446 } 447