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