tmpfs_vfsops.c revision 1.48
1/* $NetBSD: tmpfs_vfsops.c,v 1.48 2011/05/19 03:21:23 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 1.48 2011/05/19 03:21:23 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/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 61MODULE(MODULE_CLASS_VFS, tmpfs, NULL); 62 63struct pool tmpfs_dirent_pool; 64struct pool tmpfs_node_pool; 65 66static int tmpfs_mount(struct mount *, const char *, void *, size_t *); 67static int tmpfs_start(struct mount *, int); 68static int tmpfs_unmount(struct mount *, int); 69static int tmpfs_root(struct mount *, struct vnode **); 70static int tmpfs_vget(struct mount *, ino_t, struct vnode **); 71static int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **); 72static int tmpfs_vptofh(struct vnode *, struct fid *, size_t *); 73static int tmpfs_statvfs(struct mount *, struct statvfs *); 74static int tmpfs_sync(struct mount *, int, kauth_cred_t); 75static void tmpfs_init(void); 76static void tmpfs_done(void); 77static int tmpfs_snapshot(struct mount *, struct vnode *, 78 struct timespec *); 79 80static void 81tmpfs_init(void) 82{ 83 84 pool_init(&tmpfs_dirent_pool, sizeof(struct tmpfs_dirent), 0, 0, 0, 85 "tmpfs_dirent", &pool_allocator_nointr, IPL_NONE); 86 pool_init(&tmpfs_node_pool, sizeof(struct tmpfs_node), 0, 0, 0, 87 "tmpfs_node", &pool_allocator_nointr, IPL_NONE); 88} 89 90static void 91tmpfs_done(void) 92{ 93 94 pool_destroy(&tmpfs_dirent_pool); 95 pool_destroy(&tmpfs_node_pool); 96} 97 98static int 99tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 100{ 101 struct tmpfs_mount *tmp; 102 struct tmpfs_node *root; 103 struct tmpfs_args *args = data; 104 uint64_t memlimit; 105 ino_t nodes; 106 int error; 107 108 if (*data_len < sizeof *args) 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 /* XXX: There is no support yet to update file system 132 * settings. Should be added. */ 133 134 return EOPNOTSUPP; 135 } 136 137 if (args->ta_version != TMPFS_ARGS_VERSION) 138 return EINVAL; 139 140 /* Do not allow mounts if we do not have enough memory to preserve 141 * the minimum reserved pages. */ 142 if (tmpfs_mem_info(true) < TMPFS_PAGES_RESERVED) 143 return EINVAL; 144 145 /* Get the memory usage limit for this file-system. */ 146 if (args->ta_size_max < PAGE_SIZE) { 147 memlimit = UINT64_MAX; 148 } else { 149 memlimit = args->ta_size_max; 150 } 151 KASSERT(memlimit > 0); 152 153 if (args->ta_nodes_max <= 3) { 154 nodes = 3 + (memlimit / 1024); 155 } else { 156 nodes = args->ta_nodes_max; 157 } 158 nodes = MIN(nodes, INT_MAX); 159 KASSERT(nodes >= 3); 160 161 /* Allocate the tmpfs mount structure and fill it. */ 162 tmp = kmem_alloc(sizeof(struct tmpfs_mount), KM_SLEEP); 163 if (tmp == NULL) 164 return ENOMEM; 165 166 tmp->tm_nodes_max = nodes; 167 tmp->tm_nodes_cnt = 0; 168 LIST_INIT(&tmp->tm_nodes); 169 170 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE); 171 tmpfs_mntmem_init(tmp, memlimit); 172 173 /* Allocate the root node. */ 174 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid, 175 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL, 176 VNOVAL, &root); 177 KASSERT(error == 0 && root != NULL); 178 root->tn_links++; 179 tmp->tm_root = root; 180 181 mp->mnt_data = tmp; 182 mp->mnt_flag |= MNT_LOCAL; 183 mp->mnt_stat.f_namemax = MAXNAMLEN; 184 mp->mnt_fs_bshift = PAGE_SHIFT; 185 mp->mnt_dev_bshift = DEV_BSHIFT; 186 mp->mnt_iflag |= IMNT_MPSAFE; 187 vfs_getnewfsid(mp); 188 189 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE, 190 mp->mnt_op->vfs_name, mp, curlwp); 191 if (error) { 192 (void)tmpfs_unmount(mp, MNT_FORCE); 193 } 194 return error; 195} 196 197/* --------------------------------------------------------------------- */ 198 199static int 200tmpfs_start(struct mount *mp, int flags) 201{ 202 203 return 0; 204} 205 206static int 207tmpfs_unmount(struct mount *mp, int mntflags) 208{ 209 struct tmpfs_mount *tmp; 210 struct tmpfs_node *node; 211 int error, flags = 0; 212 213 /* Handle forced unmounts. */ 214 if (mntflags & MNT_FORCE) 215 flags |= FORCECLOSE; 216 217 /* Finalize all pending I/O. */ 218 error = vflush(mp, NULL, flags); 219 if (error != 0) 220 return error; 221 222 tmp = VFS_TO_TMPFS(mp); 223 224 /* Free all associated data. The loop iterates over the linked list 225 * we have containing all used nodes. For each of them that is 226 * a directory, we free all its directory entries. Note that after 227 * freeing a node, it will automatically go to the available list, 228 * so we will later have to iterate over it to release its items. */ 229 node = LIST_FIRST(&tmp->tm_nodes); 230 while (node != NULL) { 231 struct tmpfs_node *next; 232 233 if (node->tn_type == VDIR) { 234 struct tmpfs_dirent *de; 235 236 de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir); 237 while (de != NULL) { 238 struct tmpfs_dirent *nde; 239 240 nde = TAILQ_NEXT(de, td_entries); 241 tmpfs_free_dirent(tmp, de, false); 242 de = nde; 243 node->tn_size -= sizeof(struct tmpfs_dirent); 244 } 245 } 246 247 next = LIST_NEXT(node, tn_entries); 248 tmpfs_free_node(tmp, node); 249 node = next; 250 } 251 252 /* Throw away the tmpfs_mount structure. */ 253 tmpfs_mntmem_destroy(tmp); 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 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) : ESTALE; 311} 312 313/* --------------------------------------------------------------------- */ 314 315static int 316tmpfs_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 339static int 340tmpfs_statvfs(struct mount *mp, struct statvfs *sbp) 341{ 342 struct tmpfs_mount *tmp; 343 fsfilcnt_t freenodes; 344 size_t avail; 345 346 tmp = VFS_TO_TMPFS(mp); 347 348 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE; 349 350 mutex_enter(&tmp->tm_acc_lock); 351 avail = tmpfs_pages_avail(tmp); 352 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT); 353 sbp->f_bavail = sbp->f_bfree = avail; 354 sbp->f_bresvd = 0; 355 356 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt, 357 avail * PAGE_SIZE / sizeof(struct tmpfs_node)); 358 359 sbp->f_files = tmp->tm_nodes_cnt + freenodes; 360 sbp->f_favail = sbp->f_ffree = freenodes; 361 sbp->f_fresvd = 0; 362 mutex_exit(&tmp->tm_acc_lock); 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 380static int 381tmpfs_snapshot(struct mount *mp, struct vnode *vp, 382 struct timespec *ctime) 383{ 384 385 return EOPNOTSUPP; 386} 387 388/* --------------------------------------------------------------------- */ 389 390/* 391 * tmpfs vfs operations. 392 */ 393 394extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc; 395extern const struct vnodeopv_desc tmpfs_specop_opv_desc; 396extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc; 397 398const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = { 399 &tmpfs_fifoop_opv_desc, 400 &tmpfs_specop_opv_desc, 401 &tmpfs_vnodeop_opv_desc, 402 NULL, 403}; 404 405struct vfsops tmpfs_vfsops = { 406 MOUNT_TMPFS, /* vfs_name */ 407 sizeof (struct tmpfs_args), 408 tmpfs_mount, /* vfs_mount */ 409 tmpfs_start, /* vfs_start */ 410 tmpfs_unmount, /* vfs_unmount */ 411 tmpfs_root, /* vfs_root */ 412 (void *)eopnotsupp, /* vfs_quotactl */ 413 tmpfs_statvfs, /* vfs_statvfs */ 414 tmpfs_sync, /* vfs_sync */ 415 tmpfs_vget, /* vfs_vget */ 416 tmpfs_fhtovp, /* vfs_fhtovp */ 417 tmpfs_vptofh, /* vfs_vptofh */ 418 tmpfs_init, /* vfs_init */ 419 NULL, /* vfs_reinit */ 420 tmpfs_done, /* vfs_done */ 421 NULL, /* vfs_mountroot */ 422 tmpfs_snapshot, /* vfs_snapshot */ 423 vfs_stdextattrctl, /* vfs_extattrctl */ 424 (void *)eopnotsupp, /* vfs_suspendctl */ 425 genfs_renamelock_enter, 426 genfs_renamelock_exit, 427 (void *)eopnotsupp, 428 tmpfs_vnodeopv_descs, 429 0, /* vfs_refcount */ 430 { NULL, NULL }, 431}; 432 433static int 434tmpfs_modcmd(modcmd_t cmd, void *arg) 435{ 436 437 switch (cmd) { 438 case MODULE_CMD_INIT: 439 return vfs_attach(&tmpfs_vfsops); 440 case MODULE_CMD_FINI: 441 return vfs_detach(&tmpfs_vfsops); 442 default: 443 return ENOTTY; 444 } 445} 446