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         /* Flush all readers on this fs */
 204         wake_up_all(&fc->waitq);
 205         up_write(&fc->sbput_sem);
 206         fuse_release_conn(fc);
 207         spin_unlock(&fuse_lock);
 208 }
 209
 210 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 211 {
 212         stbuf->f_type    = FUSE_SUPER_MAGIC;
 213         stbuf->f_bsize   = attr->bsize;
 214         stbuf->f_frsize  = attr->frsize;
 215         stbuf->f_blocks  = attr->blocks;
 216         stbuf->f_bfree   = attr->bfree;
 217         stbuf->f_bavail  = attr->bavail;
 218         stbuf->f_files   = attr->files;
 219         stbuf->f_ffree   = attr->ffree;
 220         stbuf->f_namelen = attr->namelen;
 221         /* fsid is left zero */
 222 }
 223
 224 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
 225 {
 226         struct fuse_conn *fc = get_fuse_conn_super(sb);
 227         struct fuse_req *req;
 228         struct fuse_statfs_out outarg;
 229         int err;
 230
 231         req = fuse_get_request(fc);
 232         if (!req)
 233                 return -EINTR;
 234
 235         memset(&outarg, 0, sizeof(outarg));
 236         req->in.numargs = 0;
 237         req->in.h.opcode = FUSE_STATFS;
 238         req->out.numargs = 1;
 239         req->out.args[0].size =
 240                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 241         req->out.args[0].value = &outarg;
 242         request_send(fc, req);
 243         err = req->out.h.error;
 244         if (!err)
 245                 convert_fuse_statfs(buf, &outarg.st);
 246         fuse_put_request(fc, req);
 247         return err;
 248 }
 249
 250 enum {
 251         OPT_FD,
 252         OPT_ROOTMODE,
 253         OPT_USER_ID,
 254         OPT_GROUP_ID,
 255         OPT_DEFAULT_PERMISSIONS,
 256         OPT_ALLOW_OTHER,
 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_MAX_READ,                  "max_read=%u"},
 269         {OPT_ERR,                       NULL}
 270 };
 271
 272 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
 273 {
 274         char *p;
 275         memset(d, 0, sizeof(struct fuse_mount_data));
 276         d->max_read = ~0;
 277
 278         while ((p = strsep(&opt, ",")) != NULL) {
 279                 int token;
 280                 int value;
 281                 substring_t args[MAX_OPT_ARGS];
 282                 if (!*p)
 283                         continue;
 284
 285                 token = match_token(p, tokens, args);
 286                 switch (token) {
 287                 case OPT_FD:
 288                         if (match_int(&args[0], &value))
 289                                 return 0;
 290                         d->fd = value;
 291                         d->fd_present = 1;
 292                         break;
 293
 294                 case OPT_ROOTMODE:
 295                         if (match_octal(&args[0], &value))
 296                                 return 0;
 297                         d->rootmode = value;
 298                         d->rootmode_present = 1;
 299                         break;
 300
 301                 case OPT_USER_ID:
 302                         if (match_int(&args[0], &value))
 303                                 return 0;
 304                         d->user_id = value;
 305                         d->user_id_present = 1;
 306                         break;
 307
 308                 case OPT_GROUP_ID:
 309                         if (match_int(&args[0], &value))
 310                                 return 0;
 311                         d->group_id = value;
 312                         d->group_id_present = 1;
 313                         break;
 314
 315                 case OPT_DEFAULT_PERMISSIONS:
 316                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 317                         break;
 318
 319                 case OPT_ALLOW_OTHER:
 320                         d->flags |= FUSE_ALLOW_OTHER;
 321                         break;
 322
 323                 case OPT_MAX_READ:
 324                         if (match_int(&args[0], &value))
 325                                 return 0;
 326                         d->max_read = value;
 327                         break;
 328
 329                 default:
 330                         return 0;
 331                 }
 332         }
 333
 334         if (!d->fd_present || !d->rootmode_present ||
 335             !d->user_id_present || !d->group_id_present)
 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->max_read != ~0)
 352                 seq_printf(m, ",max_read=%u", fc->max_read);
 353         return 0;
 354 }
 355
 356 static void free_conn(struct fuse_conn *fc)
 357 {
 358         while (!list_empty(&fc->unused_list)) {
 359                 struct fuse_req *req;
 360                 req = list_entry(fc->unused_list.next, struct fuse_req, list);
 361                 list_del(&req->list);
 362                 fuse_request_free(req);
 363         }
 364         kfree(fc);
 365 }
 366
 367 /* Must be called with the fuse lock held */
 368 void fuse_release_conn(struct fuse_conn *fc)
 369 {
 370         fc->count--;
 371         if (!fc->count)
 372                 free_conn(fc);
 373 }
 374
 375 static struct fuse_conn *new_conn(void)
 376 {
 377         struct fuse_conn *fc;
 378
 379         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
 380         if (fc != NULL) {
 381                 int i;
 382                 init_waitqueue_head(&fc->waitq);
 383                 INIT_LIST_HEAD(&fc->pending);
 384                 INIT_LIST_HEAD(&fc->processing);
 385                 INIT_LIST_HEAD(&fc->unused_list);
 386                 INIT_LIST_HEAD(&fc->background);
 387                 sema_init(&fc->outstanding_sem, 1); /* One for INIT */
 388                 init_rwsem(&fc->sbput_sem);
 389                 for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
 390                         struct fuse_req *req = fuse_request_alloc();
 391                         if (!req) {
 392                                 free_conn(fc);
 393                                 return NULL;
 394                         }
 395                         list_add(&req->list, &fc->unused_list);
 396                 }
 397                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 398                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
 399                 fc->reqctr = 0;
 400         }
 401         return fc;
 402 }
 403
 404 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
 405 {
 406         struct fuse_conn *fc;
 407
 408         if (file->f_op != &fuse_dev_operations)
 409                 return ERR_PTR(-EINVAL);
 410         fc = new_conn();
 411         if (fc == NULL)
 412                 return ERR_PTR(-ENOMEM);
 413         spin_lock(&fuse_lock);
 414         if (file->private_data) {
 415                 free_conn(fc);
 416                 fc = ERR_PTR(-EINVAL);
 417         } else {
 418                 file->private_data = fc;
 419                 sb->s_fs_info = fc;
 420                 fc->mounted = 1;
 421                 fc->connected = 1;
 422                 fc->count = 2;
 423         }
 424         spin_unlock(&fuse_lock);
 425         return fc;
 426 }
 427
 428 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 429 {
 430         struct fuse_attr attr;
 431         memset(&attr, 0, sizeof(attr));
 432
 433         attr.mode = mode;
 434         attr.ino = FUSE_ROOT_ID;
 435         return fuse_iget(sb, 1, 0, &attr);
 436 }
 437
 438 static struct super_operations fuse_super_operations = {
 439         .alloc_inode    = fuse_alloc_inode,
 440         .destroy_inode  = fuse_destroy_inode,
 441         .read_inode     = fuse_read_inode,
 442         .clear_inode    = fuse_clear_inode,
 443         .put_super      = fuse_put_super,
 444         .statfs         = fuse_statfs,
 445         .show_options   = fuse_show_options,
 446 };
 447
 448 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 449 {
 450         struct fuse_conn *fc;
 451         struct inode *root;
 452         struct fuse_mount_data d;
 453         struct file *file;
 454         int err;
 455
 456         if (!parse_fuse_opt((char *) data, &d))
 457                 return -EINVAL;
 458
 459         sb->s_blocksize = PAGE_CACHE_SIZE;
 460         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 461         sb->s_magic = FUSE_SUPER_MAGIC;
 462         sb->s_op = &fuse_super_operations;
 463         sb->s_maxbytes = MAX_LFS_FILESIZE;
 464
 465         file = fget(d.fd);
 466         if (!file)
 467                 return -EINVAL;
 468
 469         fc = get_conn(file, sb);
 470         fput(file);
 471         if (IS_ERR(fc))
 472                 return PTR_ERR(fc);
 473
 474         fc->flags = d.flags;
 475         fc->user_id = d.user_id;
 476         fc->group_id = d.group_id;
 477         fc->max_read = d.max_read;
 478         if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)
 479                 fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 480
 481         err = -ENOMEM;
 482         root = get_root_inode(sb, d.rootmode);
 483         if (root == NULL)
 484                 goto err;
 485
 486         sb->s_root = d_alloc_root(root);
 487         if (!sb->s_root) {
 488                 iput(root);
 489                 goto err;
 490         }
 491         fuse_send_init(fc);
 492         return 0;
 493
 494  err:
 495         spin_lock(&fuse_lock);
 496         fuse_release_conn(fc);
 497         spin_unlock(&fuse_lock);
 498         return err;
 499 }
 500
 501 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
 502                                        int flags, const char *dev_name,
 503                                        void *raw_data)
 504 {
 505         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
 506 }
 507
 508 static struct file_system_type fuse_fs_type = {
 509         .owner          = THIS_MODULE,
 510         .name           = "fuse",
 511         .get_sb         = fuse_get_sb,
 512         .kill_sb        = kill_anon_super,
 513 };
 514
 515 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
 516                                  unsigned long flags)
 517 {
 518         struct inode * inode = foo;
 519
 520         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 521             SLAB_CTOR_CONSTRUCTOR)
 522                 inode_init_once(inode);
 523 }
 524
 525 static int __init fuse_fs_init(void)
 526 {
 527         int err;
 528
 529         err = register_filesystem(&fuse_fs_type);
 530         if (err)
 531                 printk("fuse: failed to register filesystem\n");
 532         else {
 533                 fuse_inode_cachep = kmem_cache_create("fuse_inode",
 534                                                       sizeof(struct fuse_inode),
 535                                                       0, SLAB_HWCACHE_ALIGN,
 536                                                       fuse_inode_init_once, NULL);
 537                 if (!fuse_inode_cachep) {
 538                         unregister_filesystem(&fuse_fs_type);
 539                         err = -ENOMEM;
 540                 }
 541         }
 542
 543         return err;
 544 }
 545
 546 static void fuse_fs_cleanup(void)
 547 {
 548         unregister_filesystem(&fuse_fs_type);
 549         kmem_cache_destroy(fuse_inode_cachep);
 550 }
 551
 552 static int __init fuse_init(void)
 553 {
 554         int res;
 555
 556         printk("fuse init (API version %i.%i)\n",
 557                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
 558
 559         spin_lock_init(&fuse_lock);
 560         res = fuse_fs_init();
 561         if (res)
 562                 goto err;
 563
 564         res = fuse_dev_init();
 565         if (res)
 566                 goto err_fs_cleanup;
 567
 568         return 0;
 569
 570  err_fs_cleanup:
 571         fuse_fs_cleanup();
 572  err:
 573         return res;
 574 }
 575
 576 static void __exit fuse_exit(void)
 577 {
 578         printk(KERN_DEBUG "fuse exit\n");
 579
 580         fuse_fs_cleanup();
 581         fuse_dev_cleanup();
 582 }
 583
 584 module_init(fuse_init);
 585 module_exit(fuse_exit);