fs/fuse/inode.c

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