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