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   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/file.h>
  14 #include <linux/mount.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/parser.h>
  19 #include <linux/statfs.h>
  20
  21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  22 MODULE_DESCRIPTION("Filesystem in Userspace");
  23 MODULE_LICENSE("GPL");
  24
  25 spinlock_t fuse_lock;
  26 static kmem_cache_t *fuse_inode_cachep;
  27
  28 #define FUSE_SUPER_MAGIC 0x65735546
  29
  30 struct fuse_mount_data {
  31         int fd;
  32         unsigned rootmode;
  33         unsigned user_id;
  34         unsigned group_id;
  35         unsigned fd_present : 1;
  36         unsigned rootmode_present : 1;
  37         unsigned user_id_present : 1;
  38         unsigned group_id_present : 1;
  39         unsigned flags;
  40         unsigned max_read;
  41 };
  42
  43 static struct inode *fuse_alloc_inode(struct super_block *sb)
  44 {
  45         struct inode *inode;
  46         struct fuse_inode *fi;
  47
  48         inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
  49         if (!inode)
  50                 return NULL;
  51
  52         fi = get_fuse_inode(inode);
  53         fi->i_time = jiffies - 1;
  54         fi->nodeid = 0;
  55         fi->nlookup = 0;
  56         fi->forget_req = fuse_request_alloc();
  57         if (!fi->forget_req) {
  58                 kmem_cache_free(fuse_inode_cachep, inode);
  59                 return NULL;
  60         }
  61
  62         return inode;
  63 }
  64
  65 static void fuse_destroy_inode(struct inode *inode)
  66 {
  67         struct fuse_inode *fi = get_fuse_inode(inode);
  68         if (fi->forget_req)
  69                 fuse_request_free(fi->forget_req);
  70         kmem_cache_free(fuse_inode_cachep, inode);
  71 }
  72
  73 static void fuse_read_inode(struct inode *inode)
  74 {
  75         /* No op */
  76 }
  77
  78 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
  79                       unsigned long nodeid, u64 nlookup)
  80 {
  81         struct fuse_forget_in *inarg = &req->misc.forget_in;
  82         inarg->nlookup = nlookup;
  83         req->in.h.opcode = FUSE_FORGET;
  84         req->in.h.nodeid = nodeid;
  85         req->in.numargs = 1;
  86         req->in.args[0].size = sizeof(struct fuse_forget_in);
  87         req->in.args[0].value = inarg;
  88         request_send_noreply(fc, req);
  89 }
  90
  91 static void fuse_clear_inode(struct inode *inode)
  92 {
  93         if (inode->i_sb->s_flags & MS_ACTIVE) {
  94                 struct fuse_conn *fc = get_fuse_conn(inode);
  95                 struct fuse_inode *fi = get_fuse_inode(inode);
  96                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
  97                 fi->forget_req = NULL;
  98         }
  99 }
 100
 101 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
 102 {
 103         if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
 104                 invalidate_inode_pages(inode->i_mapping);
 105
 106         inode->i_ino     = attr->ino;
 107         inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
 108         inode->i_nlink   = attr->nlink;
 109         inode->i_uid     = attr->uid;
 110         inode->i_gid     = attr->gid;
 111         i_size_write(inode, attr->size);
 112         inode->i_blksize = PAGE_CACHE_SIZE;
 113         inode->i_blocks  = attr->blocks;
 114         inode->i_atime.tv_sec   = attr->atime;
 115         inode->i_atime.tv_nsec  = attr->atimensec;
 116         inode->i_mtime.tv_sec   = attr->mtime;
 117         inode->i_mtime.tv_nsec  = attr->mtimensec;
 118         inode->i_ctime.tv_sec   = attr->ctime;
 119         inode->i_ctime.tv_nsec  = attr->ctimensec;
 120 }
 121
 122 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 123 {
 124         inode->i_mode = attr->mode & S_IFMT;
 125         i_size_write(inode, attr->size);
 126         if (S_ISREG(inode->i_mode)) {
 127                 fuse_init_common(inode);
 128                 fuse_init_file_inode(inode);
 129         } else if (S_ISDIR(inode->i_mode))
 130                 fuse_init_dir(inode);
 131         else if (S_ISLNK(inode->i_mode))
 132                 fuse_init_symlink(inode);
 133         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 134                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 135                 fuse_init_common(inode);
 136                 init_special_inode(inode, inode->i_mode,
 137                                    new_decode_dev(attr->rdev));
 138         } else {
 139                 /* Don't let user create weird files */
 140                 inode->i_mode = S_IFREG;
 141                 fuse_init_common(inode);
 142                 fuse_init_file_inode(inode);
 143         }
 144 }
 145
 146 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 147 {
 148         unsigned long nodeid = *(unsigned long *) _nodeidp;
 149         if (get_node_id(inode) == nodeid)
 150                 return 1;
 151         else
 152                 return 0;
 153 }
 154
 155 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 156 {
 157         unsigned long nodeid = *(unsigned long *) _nodeidp;
 158         get_fuse_inode(inode)->nodeid = nodeid;
 159         return 0;
 160 }
 161
 162 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 163                         int generation, struct fuse_attr *attr)
 164 {
 165         struct inode *inode;
 166         struct fuse_inode *fi;
 167         struct fuse_conn *fc = get_fuse_conn_super(sb);
 168         int retried = 0;
 169
 170  retry:
 171         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 172         if (!inode)
 173                 return NULL;
 174
 175         if ((inode->i_state & I_NEW)) {
 176                 inode->i_generation = generation;
 177                 inode->i_data.backing_dev_info = &fc->bdi;
 178                 fuse_init_inode(inode, attr);
 179                 unlock_new_inode(inode);
 180         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 181                 BUG_ON(retried);
 182                 /* Inode has changed type, any I/O on the old should fail */
 183                 make_bad_inode(inode);
 184                 iput(inode);
 185                 retried = 1;
 186                 goto retry;
 187         }
 188
 189         fi = get_fuse_inode(inode);
 190         fi->nlookup ++;
 191         fuse_change_attributes(inode, attr);
 192         return inode;
 193 }
 194
 195 static void fuse_put_super(struct super_block *sb)
 196 {
 197         struct fuse_conn *fc = get_fuse_conn_super(sb);
 198
 199         down_write(&fc->sbput_sem);
 200         while (!list_empty(&fc->background))
 201                 fuse_release_background(list_entry(fc->background.next,
 202                                                    struct fuse_req, bg_entry));
 203
 204         spin_lock(&fuse_lock);
 205         fc->mounted = 0;
 206         fc->user_id = 0;
 207         fc->group_id = 0;
 208         fc->flags = 0;
 209         /* Flush all readers on this fs */
 210         wake_up_all(&fc->waitq);
 211         up_write(&fc->sbput_sem);
 212         fuse_release_conn(fc);
 213         spin_unlock(&fuse_lock);
 214 }
 215
 216 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 217 {
 218         stbuf->f_type    = FUSE_SUPER_MAGIC;
 219         stbuf->f_bsize   = attr->bsize;
 220         stbuf->f_blocks  = attr->blocks;
 221         stbuf->f_bfree   = attr->bfree;
 222         stbuf->f_bavail  = attr->bavail;
 223         stbuf->f_files   = attr->files;
 224         stbuf->f_ffree   = attr->ffree;
 225         stbuf->f_namelen = attr->namelen;
 226         /* fsid is left zero */
 227 }
 228
 229 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
 230 {
 231         struct fuse_conn *fc = get_fuse_conn_super(sb);
 232         struct fuse_req *req;
 233         struct fuse_statfs_out outarg;
 234         int err;
 235
 236         req = fuse_get_request(fc);
 237         if (!req)
 238                 return -ERESTARTSYS;
 239
 240         req->in.numargs = 0;
 241         req->in.h.opcode = FUSE_STATFS;
 242         req->out.numargs = 1;
 243         req->out.args[0].size = sizeof(outarg);
 244         req->out.args[0].value = &outarg;
 245         request_send(fc, req);
 246         err = req->out.h.error;
 247         if (!err)
 248                 convert_fuse_statfs(buf, &outarg.st);
 249         fuse_put_request(fc, req);
 250         return err;
 251 }
 252
 253 enum {
 254         OPT_FD,
 255         OPT_ROOTMODE,
 256         OPT_USER_ID,
 257         OPT_GROUP_ID,
 258         OPT_DEFAULT_PERMISSIONS,
 259         OPT_ALLOW_OTHER,
 260         OPT_KERNEL_CACHE,
 261         OPT_DIRECT_IO,
 262         OPT_MAX_READ,
 263         OPT_ERR
 264 };
 265
 266 static match_table_t tokens = {
 267         {OPT_FD,                        "fd=%u"},
 268         {OPT_ROOTMODE,                  "rootmode=%o"},
 269         {OPT_USER_ID,                   "user_id=%u"},
 270         {OPT_GROUP_ID,                  "group_id=%u"},
 271         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 272         {OPT_ALLOW_OTHER,               "allow_other"},
 273         {OPT_KERNEL_CACHE,              "kernel_cache"},
 274         {OPT_DIRECT_IO,                 "direct_io"},
 275         {OPT_MAX_READ,                  "max_read=%u"},
 276         {OPT_ERR,                       NULL}
 277 };
 278
 279 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
 280 {
 281         char *p;
 282         memset(d, 0, sizeof(struct fuse_mount_data));
 283         d->max_read = ~0;
 284
 285         while ((p = strsep(&opt, ",")) != NULL) {
 286                 int token;
 287                 int value;
 288                 substring_t args[MAX_OPT_ARGS];
 289                 if (!*p)
 290                         continue;
 291
 292                 token = match_token(p, tokens, args);
 293                 switch (token) {
 294                 case OPT_FD:
 295                         if (match_int(&args[0], &value))
 296                                 return 0;
 297                         d->fd = value;
 298                         d->fd_present = 1;
 299                         break;
 300
 301                 case OPT_ROOTMODE:
 302                         if (match_octal(&args[0], &value))
 303                                 return 0;
 304                         d->rootmode = value;
 305                         d->rootmode_present = 1;
 306                         break;
 307
 308                 case OPT_USER_ID:
 309                         if (match_int(&args[0], &value))
 310                                 return 0;
 311                         d->user_id = value;
 312                         d->user_id_present = 1;
 313                         break;
 314
 315                 case OPT_GROUP_ID:
 316                         if (match_int(&args[0], &value))
 317                                 return 0;
 318                         d->group_id = value;
 319                         d->group_id_present = 1;
 320                         break;
 321
 322                 case OPT_DEFAULT_PERMISSIONS:
 323                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 324                         break;
 325
 326                 case OPT_ALLOW_OTHER:
 327                         d->flags |= FUSE_ALLOW_OTHER;
 328                         break;
 329
 330                 case OPT_KERNEL_CACHE:
 331                         d->flags |= FUSE_KERNEL_CACHE;
 332                         break;
 333
 334                 case OPT_DIRECT_IO:
 335                         d->flags |= FUSE_DIRECT_IO;
 336                         break;
 337
 338                 case OPT_MAX_READ:
 339                         if (match_int(&args[0], &value))
 340                                 return 0;
 341                         d->max_read = value;
 342                         break;
 343
 344                 default:
 345                         return 0;
 346                 }
 347         }
 348
 349         if (!d->fd_present || !d->rootmode_present ||
 350             !d->user_id_present || !d->group_id_present)
 351                 return 0;
 352
 353         return 1;
 354 }
 355
 356 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 357 {
 358         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 359
 360         seq_printf(m, ",user_id=%u", fc->user_id);
 361         seq_printf(m, ",group_id=%u", fc->group_id);
 362         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 363                 seq_puts(m, ",default_permissions");
 364         if (fc->flags & FUSE_ALLOW_OTHER)
 365                 seq_puts(m, ",allow_other");
 366         if (fc->flags & FUSE_KERNEL_CACHE)
 367                 seq_puts(m, ",kernel_cache");
 368         if (fc->flags & FUSE_DIRECT_IO)
 369                 seq_puts(m, ",direct_io");
 370         if (fc->max_read != ~0)
 371                 seq_printf(m, ",max_read=%u", fc->max_read);
 372         return 0;
 373 }
 374
 375 static void free_conn(struct fuse_conn *fc)
 376 {
 377         while (!list_empty(&fc->unused_list)) {
 378                 struct fuse_req *req;
 379                 req = list_entry(fc->unused_list.next, struct fuse_req, list);
 380                 list_del(&req->list);
 381                 fuse_request_free(req);
 382         }
 383         kfree(fc);
 384 }
 385
 386 /* Must be called with the fuse lock held */
 387 void fuse_release_conn(struct fuse_conn *fc)
 388 {
 389         fc->count--;
 390         if (!fc->count)
 391                 free_conn(fc);
 392 }
 393
 394 static struct fuse_conn *new_conn(void)
 395 {
 396         struct fuse_conn *fc;
 397
 398         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
 399         if (fc != NULL) {
 400                 int i;
 401                 memset(fc, 0, sizeof(*fc));
 402                 init_waitqueue_head(&fc->waitq);
 403                 INIT_LIST_HEAD(&fc->pending);
 404                 INIT_LIST_HEAD(&fc->processing);
 405                 INIT_LIST_HEAD(&fc->unused_list);
 406                 INIT_LIST_HEAD(&fc->background);
 407                 sema_init(&fc->outstanding_sem, 0);
 408                 init_rwsem(&fc->sbput_sem);
 409                 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
 410                         struct fuse_req *req = fuse_request_alloc();
 411                         if (!req) {
 412                                 free_conn(fc);
 413                                 return NULL;
 414                         }
 415                         list_add(&req->list, &fc->unused_list);
 416                 }
 417                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 418                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
 419                 fc->reqctr = 0;
 420         }
 421         return fc;
 422 }
 423
 424 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
 425 {
 426         struct fuse_conn *fc;
 427
 428         if (file->f_op != &fuse_dev_operations)
 429                 return ERR_PTR(-EINVAL);
 430         fc = new_conn();
 431         if (fc == NULL)
 432                 return ERR_PTR(-ENOMEM);
 433         spin_lock(&fuse_lock);
 434         if (file->private_data) {
 435                 free_conn(fc);
 436                 fc = ERR_PTR(-EINVAL);
 437         } else {
 438                 file->private_data = fc;
 439                 *get_fuse_conn_super_p(sb) = fc;
 440                 fc->mounted = 1;
 441                 fc->connected = 1;
 442                 fc->count = 2;
 443         }
 444         spin_unlock(&fuse_lock);
 445         return fc;
 446 }
 447
 448 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 449 {
 450         struct fuse_attr attr;
 451         memset(&attr, 0, sizeof(attr));
 452
 453         attr.mode = mode;
 454         attr.ino = FUSE_ROOT_ID;
 455         return fuse_iget(sb, 1, 0, &attr);
 456 }
 457
 458 static struct super_operations fuse_super_operations = {
 459         .alloc_inode    = fuse_alloc_inode,
 460         .destroy_inode  = fuse_destroy_inode,
 461         .read_inode     = fuse_read_inode,
 462         .clear_inode    = fuse_clear_inode,
 463         .put_super      = fuse_put_super,
 464         .statfs         = fuse_statfs,
 465         .show_options   = fuse_show_options,
 466 };
 467
 468 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 469 {
 470         struct fuse_conn *fc;
 471         struct inode *root;
 472         struct fuse_mount_data d;
 473         struct file *file;
 474         int err;
 475
 476         if (!parse_fuse_opt((char *) data, &d))
 477                 return -EINVAL;
 478
 479         sb->s_blocksize = PAGE_CACHE_SIZE;
 480         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 481         sb->s_magic = FUSE_SUPER_MAGIC;
 482         sb->s_op = &fuse_super_operations;
 483         sb->s_maxbytes = MAX_LFS_FILESIZE;
 484
 485         file = fget(d.fd);
 486         if (!file)
 487                 return -EINVAL;
 488
 489         fc = get_conn(file, sb);
 490         fput(file);
 491         if (IS_ERR(fc))
 492                 return PTR_ERR(fc);
 493
 494         fc->flags = d.flags;
 495         fc->user_id = d.user_id;
 496         fc->group_id = d.group_id;
 497         fc->max_read = d.max_read;
 498         if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)
 499                 fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 500         fc->max_write = FUSE_MAX_IN / 2;
 501
 502         err = -ENOMEM;
 503         root = get_root_inode(sb, d.rootmode);
 504         if (root == NULL)
 505                 goto err;
 506
 507         sb->s_root = d_alloc_root(root);
 508         if (!sb->s_root) {
 509                 iput(root);
 510                 goto err;
 511         }
 512         fuse_send_init(fc);
 513         return 0;
 514
 515  err:
 516         spin_lock(&fuse_lock);
 517         fuse_release_conn(fc);
 518         spin_unlock(&fuse_lock);
 519         return err;
 520 }
 521
 522 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
 523                                        int flags, const char *dev_name,
 524                                        void *raw_data)
 525 {
 526         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
 527 }
 528
 529 static struct file_system_type fuse_fs_type = {
 530         .owner          = THIS_MODULE,
 531         .name           = "fuse",
 532         .get_sb         = fuse_get_sb,
 533         .kill_sb        = kill_anon_super,
 534 };
 535
 536 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
 537                                  unsigned long flags)
 538 {
 539         struct inode * inode = foo;
 540
 541         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 542             SLAB_CTOR_CONSTRUCTOR)
 543                 inode_init_once(inode);
 544 }
 545
 546 static int __init fuse_fs_init(void)
 547 {
 548         int err;
 549
 550         err = register_filesystem(&fuse_fs_type);
 551         if (err)
 552                 printk("fuse: failed to register filesystem\n");
 553         else {
 554                 fuse_inode_cachep = kmem_cache_create("fuse_inode",
 555                                                       sizeof(struct fuse_inode),
 556                                                       0, SLAB_HWCACHE_ALIGN,
 557                                                       fuse_inode_init_once, NULL);
 558                 if (!fuse_inode_cachep) {
 559                         unregister_filesystem(&fuse_fs_type);
 560                         err = -ENOMEM;
 561                 }
 562         }
 563
 564         return err;
 565 }
 566
 567 static void fuse_fs_cleanup(void)
 568 {
 569         unregister_filesystem(&fuse_fs_type);
 570         kmem_cache_destroy(fuse_inode_cachep);
 571 }
 572
 573 static int __init fuse_init(void)
 574 {
 575         int res;
 576
 577         printk("fuse init (API version %i.%i)\n",
 578                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
 579
 580         spin_lock_init(&fuse_lock);
 581         res = fuse_fs_init();
 582         if (res)
 583                 goto err;
 584
 585         res = fuse_dev_init();
 586         if (res)
 587                 goto err_fs_cleanup;
 588
 589         return 0;
 590
 591  err_fs_cleanup:
 592         fuse_fs_cleanup();
 593  err:
 594         return res;
 595 }
 596
 597 static void __exit fuse_exit(void)
 598 {
 599         printk(KERN_DEBUG "fuse exit\n");
 600
 601         fuse_fs_cleanup();
 602         fuse_dev_cleanup();
 603 }
 604
 605 module_init(fuse_init);
 606 module_exit(fuse_exit);