sys/fs/tmpfs/tmpfs_vfsops.c

   1 /*      $NetBSD: tmpfs_vfsops.c,v 1.43 2008/07/28 18:00:20 pooka 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 1.43 2008/07/28 18:00:20 pooka 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 lwp *l = curlwp;
  85         int error;
  86         ino_t nodes;
  87         size_t pages;
  88         struct tmpfs_mount *tmp;
  89         struct tmpfs_node *root;
  90         struct tmpfs_args *args = data;
  91
  92         if (*data_len < sizeof *args)
  93                 return EINVAL;
  94
  95         /* Handle retrieval of mount point arguments. */
  96         if (mp->mnt_flag & MNT_GETARGS) {
  97                 if (mp->mnt_data == NULL)
  98                         return EIO;
  99                 tmp = VFS_TO_TMPFS(mp);
 100
 101                 args->ta_version = TMPFS_ARGS_VERSION;
 102                 args->ta_nodes_max = tmp->tm_nodes_max;
 103                 args->ta_size_max = tmp->tm_pages_max * PAGE_SIZE;
 104
 105                 root = tmp->tm_root;
 106                 args->ta_root_uid = root->tn_uid;
 107                 args->ta_root_gid = root->tn_gid;
 108                 args->ta_root_mode = root->tn_mode;
 109
 110                 *data_len = sizeof *args;
 111                 return 0;
 112         }
 113
 114         if (mp->mnt_flag & MNT_UPDATE) {
 115                 /* XXX: There is no support yet to update file system
 116                  * settings.  Should be added. */
 117
 118                 return EOPNOTSUPP;
 119         }
 120
 121         if (args->ta_version != TMPFS_ARGS_VERSION)
 122                 return EINVAL;
 123
 124         /* Do not allow mounts if we do not have enough memory to preserve
 125          * the minimum reserved pages. */
 126         if (tmpfs_mem_info(true) < TMPFS_PAGES_RESERVED)
 127                 return EINVAL;
 128
 129         /* Get the maximum number of memory pages this file system is
 130          * allowed to use, based on the maximum size the user passed in
 131          * the mount structure.  A value of zero is treated as if the
 132          * maximum available space was requested. */
 133         if (args->ta_size_max < PAGE_SIZE || args->ta_size_max >= SIZE_MAX)
 134                 pages = SIZE_MAX;
 135         else
 136                 pages = args->ta_size_max / PAGE_SIZE +
 137                     (args->ta_size_max % PAGE_SIZE == 0 ? 0 : 1);
 138         if (pages > INT_MAX)
 139                 pages = INT_MAX;
 140         KASSERT(pages > 0);
 141
 142         if (args->ta_nodes_max <= 3)
 143                 nodes = 3 + pages * PAGE_SIZE / 1024;
 144         else
 145                 nodes = args->ta_nodes_max;
 146         if (nodes > INT_MAX)
 147                 nodes = INT_MAX;
 148         KASSERT(nodes >= 3);
 149
 150         /* Allocate the tmpfs mount structure and fill it. */
 151         tmp = kmem_alloc(sizeof(struct tmpfs_mount), KM_SLEEP);
 152         if (tmp == NULL)
 153                 return ENOMEM;
 154
 155         tmp->tm_nodes_max = nodes;
 156         tmp->tm_nodes_cnt = 0;
 157         LIST_INIT(&tmp->tm_nodes);
 158
 159         mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE);
 160
 161         tmp->tm_pages_max = pages;
 162         tmp->tm_pages_used = 0;
 163         tmpfs_pool_init(&tmp->tm_dirent_pool, sizeof(struct tmpfs_dirent),
 164             "dirent", tmp);
 165         tmpfs_pool_init(&tmp->tm_node_pool, sizeof(struct tmpfs_node),
 166             "node", tmp);
 167         tmpfs_str_pool_init(&tmp->tm_str_pool, tmp);
 168
 169         /* Allocate the root node. */
 170         error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid,
 171             args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL, NULL,
 172             VNOVAL, &root);
 173         KASSERT(error == 0 && root != NULL);
 174         root->tn_links++;
 175         tmp->tm_root = root;
 176
 177         mp->mnt_data = tmp;
 178         mp->mnt_flag |= MNT_LOCAL;
 179         mp->mnt_stat.f_namemax = MAXNAMLEN;
 180         mp->mnt_fs_bshift = PAGE_SHIFT;
 181         mp->mnt_dev_bshift = DEV_BSHIFT;
 182         mp->mnt_iflag |= IMNT_MPSAFE;
 183         vfs_getnewfsid(mp);
 184
 185         return set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE,
 186             mp->mnt_op->vfs_name, mp, l);
 187 }
 188
 189 /* --------------------------------------------------------------------- */
 190
 191 static int
 192 tmpfs_start(struct mount *mp, int flags)
 193 {
 194
 195         return 0;
 196 }
 197
 198 /* --------------------------------------------------------------------- */
 199
 200 /* ARGSUSED2 */
 201 static int
 202 tmpfs_unmount(struct mount *mp, int mntflags)
 203 {
 204         int error;
 205         int flags = 0;
 206         struct tmpfs_mount *tmp;
 207         struct tmpfs_node *node;
 208
 209         /* Handle forced unmounts. */
 210         if (mntflags & MNT_FORCE)
 211                 flags |= FORCECLOSE;
 212
 213         /* Finalize all pending I/O. */
 214         error = vflush(mp, NULL, flags);
 215         if (error != 0)
 216                 return error;
 217
 218         tmp = VFS_TO_TMPFS(mp);
 219
 220         /* Free all associated data.  The loop iterates over the linked list
 221          * we have containing all used nodes.  For each of them that is
 222          * a directory, we free all its directory entries.  Note that after
 223          * freeing a node, it will automatically go to the available list,
 224          * so we will later have to iterate over it to release its items. */
 225         node = LIST_FIRST(&tmp->tm_nodes);
 226         while (node != NULL) {
 227                 struct tmpfs_node *next;
 228
 229                 if (node->tn_type == VDIR) {
 230                         struct tmpfs_dirent *de;
 231
 232                         de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir);
 233                         while (de != NULL) {
 234                                 struct tmpfs_dirent *nde;
 235
 236                                 nde = TAILQ_NEXT(de, td_entries);
 237                                 tmpfs_free_dirent(tmp, de, false);
 238                                 de = nde;
 239                                 node->tn_size -= sizeof(struct tmpfs_dirent);
 240                         }
 241                 }
 242
 243                 next = LIST_NEXT(node, tn_entries);
 244                 tmpfs_free_node(tmp, node);
 245                 node = next;
 246         }
 247
 248         tmpfs_pool_destroy(&tmp->tm_dirent_pool);
 249         tmpfs_pool_destroy(&tmp->tm_node_pool);
 250         tmpfs_str_pool_destroy(&tmp->tm_str_pool);
 251
 252         KASSERT(tmp->tm_pages_used == 0);
 253
 254         /* Throw away the tmpfs_mount structure. */
 255         mutex_destroy(&tmp->tm_lock);
 256         kmem_free(tmp, sizeof(*tmp));
 257         mp->mnt_data = NULL;
 258
 259         return 0;
 260 }
 261
 262 /* --------------------------------------------------------------------- */
 263
 264 static int
 265 tmpfs_root(struct mount *mp, struct vnode **vpp)
 266 {
 267
 268         return tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, vpp);
 269 }
 270
 271 /* --------------------------------------------------------------------- */
 272
 273 static int
 274 tmpfs_vget(struct mount *mp, ino_t ino,
 275     struct vnode **vpp)
 276 {
 277
 278         printf("tmpfs_vget called; need for it unknown yet\n");
 279         return EOPNOTSUPP;
 280 }
 281
 282 /* --------------------------------------------------------------------- */
 283
 284 static int
 285 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
 286 {
 287         bool found;
 288         struct tmpfs_fid tfh;
 289         struct tmpfs_mount *tmp;
 290         struct tmpfs_node *node;
 291
 292         tmp = VFS_TO_TMPFS(mp);
 293
 294         if (fhp->fid_len != sizeof(struct tmpfs_fid))
 295                 return EINVAL;
 296
 297         memcpy(&tfh, fhp, sizeof(struct tmpfs_fid));
 298
 299         if (tfh.tf_id >= tmp->tm_nodes_max)
 300                 return EINVAL;
 301
 302         found = false;
 303         mutex_enter(&tmp->tm_lock);
 304         LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
 305                 if (node->tn_id == tfh.tf_id &&
 306                     node->tn_gen == tfh.tf_gen) {
 307                         found = true;
 308                         break;
 309                 }
 310         }
 311         mutex_exit(&tmp->tm_lock);
 312
 313         /* XXXAD nothing to prevent 'node' from being removed. */
 314         return found ? tmpfs_alloc_vp(mp, node, vpp) : EINVAL;
 315 }
 316
 317 /* --------------------------------------------------------------------- */
 318
 319 static int
 320 tmpfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
 321 {
 322         struct tmpfs_fid tfh;
 323         struct tmpfs_node *node;
 324
 325         if (*fh_size < sizeof(struct tmpfs_fid)) {
 326                 *fh_size = sizeof(struct tmpfs_fid);
 327                 return E2BIG;
 328         }
 329         *fh_size = sizeof(struct tmpfs_fid);
 330         node = VP_TO_TMPFS_NODE(vp);
 331
 332         memset(&tfh, 0, sizeof(tfh));
 333         tfh.tf_len = sizeof(struct tmpfs_fid);
 334         tfh.tf_gen = node->tn_gen;
 335         tfh.tf_id = node->tn_id;
 336         memcpy(fhp, &tfh, sizeof(tfh));
 337
 338         return 0;
 339 }
 340
 341 /* --------------------------------------------------------------------- */
 342
 343 /* ARGSUSED2 */
 344 static int
 345 tmpfs_statvfs(struct mount *mp, struct statvfs *sbp)
 346 {
 347         fsfilcnt_t freenodes;
 348         struct tmpfs_mount *tmp;
 349
 350         tmp = VFS_TO_TMPFS(mp);
 351
 352         sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE;
 353
 354         sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
 355         sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
 356         sbp->f_bresvd = 0;
 357
 358         freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt,
 359             TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
 360
 361         sbp->f_files = tmp->tm_nodes_cnt + freenodes;
 362         sbp->f_favail = sbp->f_ffree = freenodes;
 363         sbp->f_fresvd = 0;
 364
 365         copy_statvfs_info(sbp, mp);
 366
 367         return 0;
 368 }
 369
 370 /* --------------------------------------------------------------------- */
 371
 372 /* ARGSUSED0 */
 373 static int
 374 tmpfs_sync(struct mount *mp, int waitfor,
 375     kauth_cred_t uc)
 376 {
 377
 378         return 0;
 379 }
 380
 381 /* --------------------------------------------------------------------- */
 382
 383 static void
 384 tmpfs_init(void)
 385 {
 386
 387 }
 388
 389 /* --------------------------------------------------------------------- */
 390
 391 static void
 392 tmpfs_done(void)
 393 {
 394
 395 }
 396
 397 /* --------------------------------------------------------------------- */
 398
 399 static int
 400 tmpfs_snapshot(struct mount *mp, struct vnode *vp,
 401     struct timespec *ctime)
 402 {
 403
 404         return EOPNOTSUPP;
 405 }
 406
 407 /* --------------------------------------------------------------------- */
 408
 409 /*
 410  * tmpfs vfs operations.
 411  */
 412
 413 extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc;
 414 extern const struct vnodeopv_desc tmpfs_specop_opv_desc;
 415 extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc;
 416
 417 const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = {
 418         &tmpfs_fifoop_opv_desc,
 419         &tmpfs_specop_opv_desc,
 420         &tmpfs_vnodeop_opv_desc,
 421         NULL,
 422 };
 423
 424 struct vfsops tmpfs_vfsops = {
 425         MOUNT_TMPFS,                    /* vfs_name */
 426         sizeof (struct tmpfs_args),
 427         tmpfs_mount,                    /* vfs_mount */
 428         tmpfs_start,                    /* vfs_start */
 429         tmpfs_unmount,                  /* vfs_unmount */
 430         tmpfs_root,                     /* vfs_root */
 431         (void *)eopnotsupp,             /* vfs_quotactl */
 432         tmpfs_statvfs,                  /* vfs_statvfs */
 433         tmpfs_sync,                     /* vfs_sync */
 434         tmpfs_vget,                     /* vfs_vget */
 435         tmpfs_fhtovp,                   /* vfs_fhtovp */
 436         tmpfs_vptofh,                   /* vfs_vptofh */
 437         tmpfs_init,                     /* vfs_init */
 438         NULL,                           /* vfs_reinit */
 439         tmpfs_done,                     /* vfs_done */
 440         NULL,                           /* vfs_mountroot */
 441         tmpfs_snapshot,                 /* vfs_snapshot */
 442         vfs_stdextattrctl,              /* vfs_extattrctl */
 443         (void *)eopnotsupp,             /* vfs_suspendctl */
 444         genfs_renamelock_enter,
 445         genfs_renamelock_exit,
 446         (void *)eopnotsupp,
 447         tmpfs_vnodeopv_descs,
 448         0,                              /* vfs_refcount */
 449         { NULL, NULL },
 450 };
 451
 452 static int
 453 tmpfs_modcmd(modcmd_t cmd, void *arg)
 454 {
 455
 456         switch (cmd) {
 457         case MODULE_CMD_INIT:
 458                 return vfs_attach(&tmpfs_vfsops);
 459         case MODULE_CMD_FINI:
 460                 return vfs_detach(&tmpfs_vfsops);
 461         default:
 462                 return ENOTTY;
 463         }
 464 }