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 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                 BUG();
 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_flags |= S_NOATIME|S_NOCMTIME;
 173                 inode->i_generation = generation;
 174                 inode->i_data.backing_dev_info = &fc->bdi;
 175                 fuse_init_inode(inode, attr);
 176                 unlock_new_inode(inode);
 177         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 178                 BUG_ON(retried);
 179                 /* Inode has changed type, any I/O on the old should fail */
 180                 make_bad_inode(inode);
 181                 iput(inode);
 182                 retried = 1;
 183                 goto retry;
 184         }
 185
 186         fi = get_fuse_inode(inode);
 187         fi->nlookup ++;
 188         fuse_change_attributes(inode, attr);
 189         return inode;
 190 }
 191
 192 static void fuse_put_super(struct super_block *sb)
 193 {
 194         struct fuse_conn *fc = get_fuse_conn_super(sb);
 195
 196         down_write(&fc->sbput_sem);
 197         while (!list_empty(&fc->background))
 198                 fuse_release_background(list_entry(fc->background.next,
 199                                                    struct fuse_req, bg_entry));
 200
 201         spin_lock(&fuse_lock);
 202         fc->mounted = 0;
 203         fc->connected = 0;
 204         /* Flush all readers on this fs */
 205         wake_up_all(&fc->waitq);
 206         up_write(&fc->sbput_sem);
 207         fuse_release_conn(fc);
 208         spin_unlock(&fuse_lock);
 209 }
 210
 211 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 212 {
 213         stbuf->f_type    = FUSE_SUPER_MAGIC;
 214         stbuf->f_bsize   = attr->bsize;
 215         stbuf->f_frsize  = attr->frsize;
 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 -EINTR;
 235
 236         memset(&outarg, 0, sizeof(outarg));
 237         req->in.numargs = 0;
 238         req->in.h.opcode = FUSE_STATFS;
 239         req->out.numargs = 1;
 240         req->out.args[0].size =
 241                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 242         req->out.args[0].value = &outarg;
 243         request_send(fc, req);
 244         err = req->out.h.error;
 245         if (!err)
 246                 convert_fuse_statfs(buf, &outarg.st);
 247         fuse_put_request(fc, req);
 248         return err;
 249 }
 250
 251 enum {
 252         OPT_FD,
 253         OPT_ROOTMODE,
 254         OPT_USER_ID,
 255         OPT_GROUP_ID,
 256         OPT_DEFAULT_PERMISSIONS,
 257         OPT_ALLOW_OTHER,
 258         OPT_MAX_READ,
 259         OPT_ERR
 260 };
 261
 262 static match_table_t tokens = {
 263         {OPT_FD,                        "fd=%u"},
 264         {OPT_ROOTMODE,                  "rootmode=%o"},
 265         {OPT_USER_ID,                   "user_id=%u"},
 266         {OPT_GROUP_ID,                  "group_id=%u"},
 267         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 268         {OPT_ALLOW_OTHER,               "allow_other"},
 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->max_read = ~0;
 278
 279         while ((p = strsep(&opt, ",")) != NULL) {
 280                 int token;
 281                 int value;
 282                 substring_t args[MAX_OPT_ARGS];
 283                 if (!*p)
 284                         continue;
 285
 286                 token = match_token(p, tokens, args);
 287                 switch (token) {
 288                 case OPT_FD:
 289                         if (match_int(&args[0], &value))
 290                                 return 0;
 291                         d->fd = value;
 292                         d->fd_present = 1;
 293                         break;
 294
 295                 case OPT_ROOTMODE:
 296                         if (match_octal(&args[0], &value))
 297                                 return 0;
 298                         d->rootmode = value;
 299                         d->rootmode_present = 1;
 300                         break;
 301
 302                 case OPT_USER_ID:
 303                         if (match_int(&args[0], &value))
 304                                 return 0;
 305                         d->user_id = value;
 306                         d->user_id_present = 1;
 307                         break;
 308
 309                 case OPT_GROUP_ID:
 310                         if (match_int(&args[0], &value))
 311                                 return 0;
 312                         d->group_id = value;
 313                         d->group_id_present = 1;
 314                         break;
 315
 316                 case OPT_DEFAULT_PERMISSIONS:
 317                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 318                         break;
 319
 320                 case OPT_ALLOW_OTHER:
 321                         d->flags |= FUSE_ALLOW_OTHER;
 322                         break;
 323
 324                 case OPT_MAX_READ:
 325                         if (match_int(&args[0], &value))
 326                                 return 0;
 327                         d->max_read = value;
 328                         break;
 329
 330                 default:
 331                         return 0;
 332                 }
 333         }
 334
 335         if (!d->fd_present || !d->rootmode_present ||
 336             !d->user_id_present || !d->group_id_present)
 337                 return 0;
 338
 339         return 1;
 340 }
 341
 342 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 343 {
 344         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 345
 346         seq_printf(m, ",user_id=%u", fc->user_id);
 347         seq_printf(m, ",group_id=%u", fc->group_id);
 348         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 349                 seq_puts(m, ",default_permissions");
 350         if (fc->flags & FUSE_ALLOW_OTHER)
 351                 seq_puts(m, ",allow_other");
 352         if (fc->max_read != ~0)
 353                 seq_printf(m, ",max_read=%u", fc->max_read);
 354         return 0;
 355 }
 356
 357 static void free_conn(struct fuse_conn *fc)
 358 {
 359         while (!list_empty(&fc->unused_list)) {
 360                 struct fuse_req *req;
 361                 req = list_entry(fc->unused_list.next, struct fuse_req, list);
 362                 list_del(&req->list);
 363                 fuse_request_free(req);
 364         }
 365         kfree(fc);
 366 }
 367
 368 /* Must be called with the fuse lock held */
 369 void fuse_release_conn(struct fuse_conn *fc)
 370 {
 371         fc->count--;
 372         if (!fc->count)
 373                 free_conn(fc);
 374 }
 375
 376 static struct fuse_conn *new_conn(void)
 377 {
 378         struct fuse_conn *fc;
 379
 380         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
 381         if (fc != NULL) {
 382                 int i;
 383                 init_waitqueue_head(&fc->waitq);
 384                 INIT_LIST_HEAD(&fc->pending);
 385                 INIT_LIST_HEAD(&fc->processing);
 386                 INIT_LIST_HEAD(&fc->io);
 387                 INIT_LIST_HEAD(&fc->unused_list);
 388                 INIT_LIST_HEAD(&fc->background);
 389                 sema_init(&fc->outstanding_sem, 1); /* One for INIT */
 390                 init_rwsem(&fc->sbput_sem);
 391                 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
 392                         struct fuse_req *req = fuse_request_alloc();
 393                         if (!req) {
 394                                 free_conn(fc);
 395                                 return NULL;
 396                         }
 397                         list_add(&req->list, &fc->unused_list);
 398                 }
 399                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 400                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
 401                 fc->reqctr = 0;
 402         }
 403         return fc;
 404 }
 405
 406 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
 407 {
 408         struct fuse_conn *fc;
 409
 410         if (file->f_op != &fuse_dev_operations)
 411                 return ERR_PTR(-EINVAL);
 412         fc = new_conn();
 413         if (fc == NULL)
 414                 return ERR_PTR(-ENOMEM);
 415         spin_lock(&fuse_lock);
 416         if (file->private_data) {
 417                 free_conn(fc);
 418                 fc = ERR_PTR(-EINVAL);
 419         } else {
 420                 file->private_data = fc;
 421                 sb->s_fs_info = fc;
 422                 fc->mounted = 1;
 423                 fc->connected = 1;
 424                 fc->count = 2;
 425         }
 426         spin_unlock(&fuse_lock);
 427         return fc;
 428 }
 429
 430 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 431 {
 432         struct fuse_attr attr;
 433         memset(&attr, 0, sizeof(attr));
 434
 435         attr.mode = mode;
 436         attr.ino = FUSE_ROOT_ID;
 437         return fuse_iget(sb, 1, 0, &attr);
 438 }
 439
 440 static struct super_operations fuse_super_operations = {
 441         .alloc_inode    = fuse_alloc_inode,
 442         .destroy_inode  = fuse_destroy_inode,
 443         .read_inode     = fuse_read_inode,
 444         .clear_inode    = fuse_clear_inode,
 445         .put_super      = fuse_put_super,
 446         .statfs         = fuse_statfs,
 447         .show_options   = fuse_show_options,
 448 };
 449
 450 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 451 {
 452         struct fuse_conn *fc;
 453         struct inode *root;
 454         struct fuse_mount_data d;
 455         struct file *file;
 456         int err;
 457
 458         if (!parse_fuse_opt((char *) data, &d))
 459                 return -EINVAL;
 460
 461         sb->s_blocksize = PAGE_CACHE_SIZE;
 462         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 463         sb->s_magic = FUSE_SUPER_MAGIC;
 464         sb->s_op = &fuse_super_operations;
 465         sb->s_maxbytes = MAX_LFS_FILESIZE;
 466
 467         file = fget(d.fd);
 468         if (!file)
 469                 return -EINVAL;
 470
 471         fc = get_conn(file, sb);
 472         fput(file);
 473         if (IS_ERR(fc))
 474                 return PTR_ERR(fc);
 475
 476         fc->flags = d.flags;
 477         fc->user_id = d.user_id;
 478         fc->group_id = d.group_id;
 479         fc->max_read = d.max_read;
 480         if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)
 481                 fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 482
 483         err = -ENOMEM;
 484         root = get_root_inode(sb, d.rootmode);
 485         if (root == NULL)
 486                 goto err;
 487
 488         sb->s_root = d_alloc_root(root);
 489         if (!sb->s_root) {
 490                 iput(root);
 491                 goto err;
 492         }
 493         fuse_send_init(fc);
 494         return 0;
 495
 496  err:
 497         spin_lock(&fuse_lock);
 498         fuse_release_conn(fc);
 499         spin_unlock(&fuse_lock);
 500         return err;
 501 }
 502
 503 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
 504                                        int flags, const char *dev_name,
 505                                        void *raw_data)
 506 {
 507         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
 508 }
 509
 510 static struct file_system_type fuse_fs_type = {
 511         .owner          = THIS_MODULE,
 512         .name           = "fuse",
 513         .get_sb         = fuse_get_sb,
 514         .kill_sb        = kill_anon_super,
 515 };
 516
 517 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
 518                                  unsigned long flags)
 519 {
 520         struct inode * inode = foo;
 521
 522         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 523             SLAB_CTOR_CONSTRUCTOR)
 524                 inode_init_once(inode);
 525 }
 526
 527 static int __init fuse_fs_init(void)
 528 {
 529         int err;
 530
 531         err = register_filesystem(&fuse_fs_type);
 532         if (err)
 533                 printk("fuse: failed to register filesystem\n");
 534         else {
 535                 fuse_inode_cachep = kmem_cache_create("fuse_inode",
 536                                                       sizeof(struct fuse_inode),
 537                                                       0, SLAB_HWCACHE_ALIGN,
 538                                                       fuse_inode_init_once, NULL);
 539                 if (!fuse_inode_cachep) {
 540                         unregister_filesystem(&fuse_fs_type);
 541                         err = -ENOMEM;
 542                 }
 543         }
 544
 545         return err;
 546 }
 547
 548 static void fuse_fs_cleanup(void)
 549 {
 550         unregister_filesystem(&fuse_fs_type);
 551         kmem_cache_destroy(fuse_inode_cachep);
 552 }
 553
 554 static int __init fuse_init(void)
 555 {
 556         int res;
 557
 558         printk("fuse init (API version %i.%i)\n",
 559                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
 560
 561         spin_lock_init(&fuse_lock);
 562         res = fuse_fs_init();
 563         if (res)
 564                 goto err;
 565
 566         res = fuse_dev_init();
 567         if (res)
 568                 goto err_fs_cleanup;
 569
 570         return 0;
 571
 572  err_fs_cleanup:
 573         fuse_fs_cleanup();
 574  err:
 575         return res;
 576 }
 577
 578 static void __exit fuse_exit(void)
 579 {
 580         printk(KERN_DEBUG "fuse exit\n");
 581
 582         fuse_fs_cleanup();
 583         fuse_dev_cleanup();
 584 }
 585
 586 module_init(fuse_init);
 587 module_exit(fuse_exit);