tmpfs_vfsops.c revision 1.41
1/* $NetBSD: tmpfs_vfsops.c,v 1.41 2008/05/10 02:26:09 rumble 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 1.41 2008/05/10 02:26:09 rumble 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 60MODULE(MODULE_CLASS_VFS, tmpfs, NULL); 61 62/* --------------------------------------------------------------------- */ 63 64static int tmpfs_mount(struct mount *, const char *, void *, size_t *); 65static int tmpfs_start(struct mount *, int); 66static int tmpfs_unmount(struct mount *, int); 67static int tmpfs_root(struct mount *, struct vnode **); 68static int tmpfs_vget(struct mount *, ino_t, struct vnode **); 69static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); 70static int tmpfs_vptofh(struct vnode *, struct fid *, size_t *); 71static int tmpfs_statvfs(struct mount *, struct statvfs *); 72static int tmpfs_sync(struct mount *, int, kauth_cred_t); 73static void tmpfs_init(void); 74static void tmpfs_done(void); 75static int tmpfs_snapshot(struct mount *, struct vnode *, 76 struct timespec *); 77 78/* --------------------------------------------------------------------- */ 79 80static int 81tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 82{ 83 struct lwp *l = curlwp; 84 int error; 85 ino_t nodes; 86 size_t pages; 87 struct tmpfs_mount *tmp; 88 struct tmpfs_node *root; 89 struct tmpfs_args *args = data; 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_pages_max * PAGE_SIZE; 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 maximum number of memory pages this file system is 129 * allowed to use, based on the maximum size the user passed in 130 * the mount structure. A value of zero is treated as if the 131 * maximum available space was requested. */ 132 if (args->ta_size_max < PAGE_SIZE || args->ta_size_max >= SIZE_MAX) 133 pages = SIZE_MAX; 134 else 135 pages = args->ta_size_max / PAGE_SIZE + 136 (args->ta_size_max % PAGE_SIZE == 0 ? 0 : 1); 137 if (pages > INT_MAX) 138 pages = INT_MAX; 139 KASSERT(pages > 0); 140 141 if (args->ta_nodes_max <= 3) 142 nodes = 3 + pages * PAGE_SIZE / 1024; 143 else 144 nodes = args->ta_nodes_max; 145 if (nodes > INT_MAX) 146 nodes = INT_MAX; 147 KASSERT(nodes >= 3); 148 149 /* Allocate the tmpfs mount structure and fill it. */ 150 tmp = kmem_alloc(sizeof(struct tmpfs_mount), KM_SLEEP); 151 if (tmp == NULL) 152 return ENOMEM; 153 154 tmp->tm_nodes_max = nodes; 155 tmp->tm_nodes_cnt = 0; 156 LIST_INIT(&tmp->tm_nodes); 157 158 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 159 160 tmp->tm_pages_max = pages; 161 tmp->tm_pages_used = 0; 162 tmpfs_pool_init(&tmp->tm_dirent_pool, sizeof(struct tmpfs_dirent), 163 "dirent", tmp); 164 tmpfs_pool_init(&tmp->tm_node_pool, sizeof(struct tmpfs_node), 165 "node", tmp); 166 tmpfs_str_pool_init(&tmp->tm_str_pool, tmp); 167 168 /* Allocate the root node. */ 169 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 170 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL, 171 VNOVAL, &root); 172 KASSERT(error == 0 && root != NULL); 173 root->tn_links++; 174 tmp->tm_root = root; 175 176 mp->mnt_data = tmp; 177 mp->mnt_flag |= MNT_LOCAL; 178 mp->mnt_stat.f_namemax = MAXNAMLEN; 179 mp->mnt_fs_bshift = PAGE_SHIFT; 180 mp->mnt_dev_bshift = DEV_BSHIFT; 181 mp->mnt_iflag |= IMNT_MPSAFE; 182 vfs_getnewfsid(mp); 183 184 return set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 185 mp->mnt_op->vfs_name, mp, l); 186} 187 188/* --------------------------------------------------------------------- */ 189 190static int 191tmpfs_start(struct mount *mp, int flags) 192{ 193 194 return 0; 195} 196 197/* --------------------------------------------------------------------- */ 198 199/* ARGSUSED2 */ 200static int 201tmpfs_unmount(struct mount *mp, int mntflags) 202{ 203 int error; 204 int flags = 0; 205 struct tmpfs_mount *tmp; 206 struct tmpfs_node *node; 207 208 /* Handle forced unmounts. */ 209 if (mntflags & MNT_FORCE) 210 flags |= FORCECLOSE; 211 212 /* Finalize all pending I/O. */ 213 error = vflush(mp, NULL, flags); 214 if (error != 0) 215 return error; 216 217 tmp = VFS_TO_TMPFS(mp); 218 219 /* Free all associated data. The loop iterates over the linked list 220 * we have containing all used nodes. For each of them that is 221 * a directory, we free all its directory entries. Note that after 222 * freeing a node, it will automatically go to the available list, 223 * so we will later have to iterate over it to release its items. */ 224 node = LIST_FIRST(&tmp->tm_nodes); 225 while (node != NULL) { 226 struct tmpfs_node *next; 227 228 if (node->tn_type == VDIR) { 229 struct tmpfs_dirent *de; 230 231 de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); 232 while (de != NULL) { 233 struct tmpfs_dirent *nde; 234 235 nde = TAILQ_NEXT(de, td_entries); 236 tmpfs_free_dirent(tmp, de, false); 237 de = nde; 238 node->tn_size -= sizeof(struct tmpfs_dirent); 239 } 240 } 241 242 next = LIST_NEXT(node, tn_entries); 243 tmpfs_free_node(tmp, node); 244 node = next; 245 } 246 247 tmpfs_pool_destroy(&tmp->tm_dirent_pool); 248 tmpfs_pool_destroy(&tmp->tm_node_pool); 249 tmpfs_str_pool_destroy(&tmp->tm_str_pool); 250 251 KASSERT(tmp->tm_pages_used == 0); 252 253 /* Throw away the tmpfs_mount structure. */ 254 mutex_destroy(&tmp->tm_lock); 255 kmem_free(tmp, sizeof(*tmp)); 256 mp->mnt_data = NULL; 257 258 return 0; 259} 260 261/* --------------------------------------------------------------------- */ 262 263static int 264tmpfs_root(struct mount *mp, struct vnode **vpp) 265{ 266 267 return tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp); 268} 269 270/* --------------------------------------------------------------------- */ 271 272static int 273tmpfs_vget(struct mount *mp, ino_t ino, 274 struct vnode **vpp) 275{ 276 277 printf("tmpfs_vget called; need for it unknown yet\n"); 278 return EOPNOTSUPP; 279} 280 281/* --------------------------------------------------------------------- */ 282 283static int 284tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp) 285{ 286 bool found; 287 struct tmpfs_fid tfh; 288 struct tmpfs_mount *tmp; 289 struct tmpfs_node *node; 290 291 tmp = VFS_TO_TMPFS(mp); 292 293 if (fhp->fid_len != sizeof(struct tmpfs_fid)) 294 return EINVAL; 295 296 memcpy(&tfh, fhp, sizeof(struct tmpfs_fid)); 297 298 if (tfh.tf_id >= tmp->tm_nodes_max) 299 return EINVAL; 300 301 found = false; 302 mutex_enter(&tmp->tm_lock); 303 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) { 304 if (node->tn_id == tfh.tf_id && 305 node->tn_gen == tfh.tf_gen) { 306 found = true; 307 break; 308 } 309 } 310 mutex_exit(&tmp->tm_lock); 311 312 /* XXXAD nothing to prevent 'node' from being removed. */ 313 return found ? tmpfs_alloc_vp(mp, node, vpp) : EINVAL; 314} 315 316/* --------------------------------------------------------------------- */ 317 318static int 319tmpfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size) 320{ 321 struct tmpfs_fid tfh; 322 struct tmpfs_node *node; 323 324 if (*fh_size < sizeof(struct tmpfs_fid)) { 325 *fh_size = sizeof(struct tmpfs_fid); 326 return E2BIG; 327 } 328 *fh_size = sizeof(struct tmpfs_fid); 329 node = VP_TO_TMPFS_NODE(vp); 330 331 memset(&tfh, 0, sizeof(tfh)); 332 tfh.tf_len = sizeof(struct tmpfs_fid); 333 tfh.tf_gen = node->tn_gen; 334 tfh.tf_id = node->tn_id; 335 memcpy(fhp, &tfh, sizeof(tfh)); 336 337 return 0; 338} 339 340/* --------------------------------------------------------------------- */ 341 342/* ARGSUSED2 */ 343static int 344tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 345{ 346 fsfilcnt_t freenodes; 347 struct tmpfs_mount *tmp; 348 349 tmp = VFS_TO_TMPFS(mp); 350 351 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 352 353 sbp->f_blocks = TMPFS_PAGES_MAX(tmp); 354 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp); 355 sbp->f_bresvd = 0; 356 357 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 358 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node)); 359 360 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 361 sbp->f_favail = sbp->f_ffree = freenodes; 362 sbp->f_fresvd = 0; 363 364 copy_statvfs_info(sbp, mp); 365 366 return 0; 367} 368 369/* --------------------------------------------------------------------- */ 370 371/* ARGSUSED0 */ 372static int 373tmpfs_sync(struct mount *mp, int waitfor, 374 kauth_cred_t uc) 375{ 376 377 return 0; 378} 379 380/* --------------------------------------------------------------------- */ 381 382static void 383tmpfs_init(void) 384{ 385 386} 387 388/* --------------------------------------------------------------------- */ 389 390static void 391tmpfs_done(void) 392{ 393 394} 395 396/* --------------------------------------------------------------------- */ 397 398static int 399tmpfs_snapshot(struct mount *mp, struct vnode *vp, 400 struct timespec *ctime) 401{ 402 403 return EOPNOTSUPP; 404} 405 406/* --------------------------------------------------------------------- */ 407 408/* 409 * tmpfs vfs operations. 410 */ 411 412extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 413extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 414extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 415 416const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 417 &tmpfs_fifoop_opv_desc, 418 &tmpfs_specop_opv_desc, 419 &tmpfs_vnodeop_opv_desc, 420 NULL, 421}; 422 423struct vfsops tmpfs_vfsops = { 424 MOUNT_TMPFS, /* vfs_name */ 425 sizeof (struct tmpfs_args), 426 tmpfs_mount, /* vfs_mount */ 427 tmpfs_start, /* vfs_start */ 428 tmpfs_unmount, /* vfs_unmount */ 429 tmpfs_root, /* vfs_root */ 430 (void *)eopnotsupp, /* vfs_quotactl */ 431 tmpfs_statvfs, /* vfs_statvfs */ 432 tmpfs_sync, /* vfs_sync */ 433 tmpfs_vget, /* vfs_vget */ 434 tmpfs_fhtovp, /* vfs_fhtovp */ 435 tmpfs_vptofh, /* vfs_vptofh */ 436 tmpfs_init, /* vfs_init */ 437 NULL, /* vfs_reinit */ 438 tmpfs_done, /* vfs_done */ 439 NULL, /* vfs_mountroot */ 440 tmpfs_snapshot, /* vfs_snapshot */ 441 vfs_stdextattrctl, /* vfs_extattrctl */ 442 (void *)eopnotsupp, /* vfs_suspendctl */ 443 genfs_renamelock_enter, 444 genfs_renamelock_exit, 445 (void *)eopnotsupp, 446 tmpfs_vnodeopv_descs, 447 0, /* vfs_refcount */ 448 { NULL, NULL }, 449}; 450 451static int 452tmpfs_modcmd(modcmd_t cmd, void *arg) 453{ 454 455 switch (cmd) { 456 case MODULE_CMD_INIT: 457 return vfs_attach(&tmpfs_vfsops); 458 case MODULE_CMD_FINI: 459 return vfs_detach(&tmpfs_vfsops); 460 default: 461 return ENOTTY; 462 } 463} 464