1 /* $NetBSD: tmpfs_vfsops.c,v 1.55 2013/11/23 16:35:32 rmind 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 1.55 2013/11/23 16:35:32 rmind 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 /* Validate the version. */ 107 if (*data_len < sizeof(*args) || 108 args->ta_version != TMPFS_ARGS_VERSION) 109 return EINVAL; 110 111 /* Handle retrieval of mount point arguments. */ 112 if (mp->mnt_flag & MNT_GETARGS) { 113 if (mp->mnt_data == NULL) 114 return EIO; 115 tmp = VFS_TO_TMPFS(mp); 116 117 args->ta_version = TMPFS_ARGS_VERSION; 118 args->ta_nodes_max = tmp->tm_nodes_max; 119 args->ta_size_max = tmp->tm_mem_limit; 120 121 root = tmp->tm_root; 122 args->ta_root_uid = root->tn_uid; 123 args->ta_root_gid = root->tn_gid; 124 args->ta_root_mode = root->tn_mode; 125 126 *data_len = sizeof(*args); 127 return 0; 128 } 129 130 if (mp->mnt_flag & MNT_UPDATE) { 131 /* TODO */ 132 return EOPNOTSUPP; 133 } 134 135 /* Prohibit mounts if there is not enough memory. */ 136 if (tmpfs_mem_info(true) < TMPFS_PAGES_RESERVED) 137 return EINVAL; 138 139 /* Get the memory usage limit for this file-system. */ 140 if (args->ta_size_max < PAGE_SIZE) { 141 memlimit = UINT64_MAX; 142 } else { 143 memlimit = args->ta_size_max; 144 } 145 KASSERT(memlimit > 0); 146 147 if (args->ta_nodes_max <= 3) { 148 nodes = 3 + (memlimit / 1024); 149 } else { 150 nodes = args->ta_nodes_max; 151 } 152 nodes = MIN(nodes, INT_MAX); 153 KASSERT(nodes >= 3); 154 155 /* Allocate the tmpfs mount structure and fill it. */ 156 tmp = kmem_zalloc(sizeof(tmpfs_mount_t), KM_SLEEP); 157 if (tmp == NULL) 158 return ENOMEM; 159 160 tmp->tm_nodes_max = nodes; 161 tmp->tm_nodes_cnt = 0; 162 LIST_INIT(&tmp->tm_nodes); 163 164 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 165 tmpfs_mntmem_init(tmp, memlimit); 166 167 /* Allocate the root node. */ 168 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 169 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, 170 VNOVAL, &root); 171 KASSERT(error == 0 && root != NULL); 172 173 /* 174 * Parent of the root inode is itself. Also, root inode has no 175 * directory entry (i.e. is never attached), thus hold an extra 176 * reference (link) for it. 177 */ 178 root->tn_links++; 179 root->tn_spec.tn_dir.tn_parent = root; 180 tmp->tm_root = root; 181 182 mp->mnt_data = tmp; 183 mp->mnt_flag |= MNT_LOCAL; 184 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN; 185 mp->mnt_fs_bshift = PAGE_SHIFT; 186 mp->mnt_dev_bshift = DEV_BSHIFT; 187 mp->mnt_iflag |= IMNT_MPSAFE; 188 vfs_getnewfsid(mp); 189 190 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 191 mp->mnt_op->vfs_name, mp, curlwp); 192 if (error) { 193 (void)tmpfs_unmount(mp, MNT_FORCE); 194 } 195 return error; 196 } 197 198 static int 199 tmpfs_start(struct mount *mp, int flags) 200 { 201 202 return 0; 203 } 204 205 static int 206 tmpfs_unmount(struct mount *mp, int mntflags) 207 { 208 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 209 tmpfs_node_t *node, *cnode; 210 int error, flags = 0; 211 212 /* Handle forced unmounts. */ 213 if (mntflags & MNT_FORCE) 214 flags |= FORCECLOSE; 215 216 /* Finalize all pending I/O. */ 217 error = vflush(mp, NULL, flags); 218 if (error != 0) 219 return error; 220 221 /* 222 * First round, detach and destroy all directory entries. 223 * Also, clear the pointers to the vnodes - they are gone. 224 */ 225 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 226 tmpfs_dirent_t *de; 227 228 node->tn_vnode = NULL; 229 if (node->tn_type != VDIR) { 230 continue; 231 } 232 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) { 233 cnode = de->td_node; 234 if (cnode && cnode != TMPFS_NODE_WHITEOUT) { 235 cnode->tn_vnode = NULL; 236 } 237 tmpfs_dir_detach(node, de); 238 tmpfs_free_dirent(tmp, de); 239 } 240 /* Extra virtual entry (itself for the root). */ 241 node->tn_links--; 242 } 243 244 /* Release the reference on root (diagnostic). */ 245 node = tmp->tm_root; 246 node->tn_links--; 247 248 /* Second round, destroy all inodes. */ 249 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) { 250 tmpfs_free_node(tmp, node); 251 } 252 253 /* Throw away the tmpfs_mount structure. */ 254 tmpfs_mntmem_destroy(tmp); 255 mutex_destroy(&tmp->tm_lock); 256 kmem_free(tmp, sizeof(*tmp)); 257 mp->mnt_data = NULL; 258 259 return 0; 260 } 261 262 static int 263 tmpfs_root(struct mount *mp, vnode_t **vpp) 264 { 265 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root; 266 267 mutex_enter(&node->tn_vlock); 268 return tmpfs_vnode_get(mp, node, vpp); 269 } 270 271 static int 272 tmpfs_vget(struct mount *mp, ino_t ino, vnode_t **vpp) 273 { 274 275 printf("tmpfs_vget called; need for it unknown yet\n"); 276 return EOPNOTSUPP; 277 } 278 279 static int 280 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, vnode_t **vpp) 281 { 282 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp); 283 tmpfs_node_t *node; 284 tmpfs_fid_t tfh; 285 286 if (fhp->fid_len != sizeof(tmpfs_fid_t)) { 287 return EINVAL; 288 } 289 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t)); 290 291 mutex_enter(&tmp->tm_lock); 292 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 293 if (node->tn_id != tfh.tf_id) { 294 continue; 295 } 296 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) { 297 continue; 298 } 299 mutex_enter(&node->tn_vlock); 300 break; 301 } 302 mutex_exit(&tmp->tm_lock); 303 304 /* Will release the tn_vlock. */ 305 return node ? tmpfs_vnode_get(mp, node, vpp) : ESTALE; 306 } 307 308 static int 309 tmpfs_vptofh(vnode_t *vp, struct fid *fhp, size_t *fh_size) 310 { 311 tmpfs_fid_t tfh; 312 tmpfs_node_t *node; 313 314 if (*fh_size < sizeof(tmpfs_fid_t)) { 315 *fh_size = sizeof(tmpfs_fid_t); 316 return E2BIG; 317 } 318 *fh_size = sizeof(tmpfs_fid_t); 319 node = VP_TO_TMPFS_NODE(vp); 320 321 memset(&tfh, 0, sizeof(tfh)); 322 tfh.tf_len = sizeof(tmpfs_fid_t); 323 tfh.tf_gen = TMPFS_NODE_GEN(node); 324 tfh.tf_id = node->tn_id; 325 memcpy(fhp, &tfh, sizeof(tfh)); 326 327 return 0; 328 } 329 330 static int 331 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 332 { 333 tmpfs_mount_t *tmp; 334 fsfilcnt_t freenodes; 335 size_t avail; 336 337 tmp = VFS_TO_TMPFS(mp); 338 339 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 340 341 mutex_enter(&tmp->tm_acc_lock); 342 avail = tmpfs_pages_avail(tmp); 343 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 344 sbp->f_bavail = sbp->f_bfree = avail; 345 sbp->f_bresvd = 0; 346 347 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 348 avail * PAGE_SIZE / sizeof(tmpfs_node_t)); 349 350 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 351 sbp->f_favail = sbp->f_ffree = freenodes; 352 sbp->f_fresvd = 0; 353 mutex_exit(&tmp->tm_acc_lock); 354 355 copy_statvfs_info(sbp, mp); 356 357 return 0; 358 } 359 360 static int 361 tmpfs_sync(struct mount *mp, int waitfor, kauth_cred_t uc) 362 { 363 364 return 0; 365 } 366 367 static int 368 tmpfs_snapshot(struct mount *mp, vnode_t *vp, struct timespec *ctime) 369 { 370 371 return EOPNOTSUPP; 372 } 373 374 /* 375 * tmpfs vfs operations. 376 */ 377 378 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 379 extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 380 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 381 382 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 383 &tmpfs_fifoop_opv_desc, 384 &tmpfs_specop_opv_desc, 385 &tmpfs_vnodeop_opv_desc, 386 NULL, 387 }; 388 389 struct vfsops tmpfs_vfsops = { 390 MOUNT_TMPFS, /* vfs_name */ 391 sizeof (struct tmpfs_args), 392 tmpfs_mount, /* vfs_mount */ 393 tmpfs_start, /* vfs_start */ 394 tmpfs_unmount, /* vfs_unmount */ 395 tmpfs_root, /* vfs_root */ 396 (void *)eopnotsupp, /* vfs_quotactl */ 397 tmpfs_statvfs, /* vfs_statvfs */ 398 tmpfs_sync, /* vfs_sync */ 399 tmpfs_vget, /* vfs_vget */ 400 tmpfs_fhtovp, /* vfs_fhtovp */ 401 tmpfs_vptofh, /* vfs_vptofh */ 402 tmpfs_init, /* vfs_init */ 403 NULL, /* vfs_reinit */ 404 tmpfs_done, /* vfs_done */ 405 NULL, /* vfs_mountroot */ 406 tmpfs_snapshot, /* vfs_snapshot */ 407 vfs_stdextattrctl, /* vfs_extattrctl */ 408 (void *)eopnotsupp, /* vfs_suspendctl */ 409 genfs_renamelock_enter, 410 genfs_renamelock_exit, 411 (void *)eopnotsupp, 412 tmpfs_vnodeopv_descs, 413 0, /* vfs_refcount */ 414 { NULL, NULL }, 415 }; 416 417 static int 418 tmpfs_modcmd(modcmd_t cmd, void *arg) 419 { 420 421 switch (cmd) { 422 case MODULE_CMD_INIT: 423 return vfs_attach(&tmpfs_vfsops); 424 case MODULE_CMD_FINI: 425 return vfs_detach(&tmpfs_vfsops); 426 default: 427 return ENOTTY; 428 } 429 } 430