fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  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/seq_file.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/parser.h>
  19 #include <linux/statfs.h>
  20 #include <linux/random.h>
  21 #include <linux/sched.h>
  22 #include <linux/exportfs.h>
  23
  24 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  25 MODULE_DESCRIPTION("Filesystem in Userspace");
  26 MODULE_LICENSE("GPL");
  27
  28 static struct kmem_cache *fuse_inode_cachep;
  29 struct list_head fuse_conn_list;
  30 DEFINE_MUTEX(fuse_mutex);
  31
  32 static int set_global_limit(const char *val, struct kernel_param *kp);
  33
  34 unsigned max_user_bgreq;
  35 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  36                   &max_user_bgreq, 0644);
  37 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
  38 MODULE_PARM_DESC(max_user_bgreq,
  39  "Global limit for the maximum number of backgrounded requests an "
  40  "unprivileged user can set");
  41
  42 unsigned max_user_congthresh;
  43 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  44                   &max_user_congthresh, 0644);
  45 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
  46 MODULE_PARM_DESC(max_user_congthresh,
  47  "Global limit for the maximum congestion threshold an "
  48  "unprivileged user can set");
  49
  50 #define FUSE_SUPER_MAGIC 0x65735546
  51
  52 #define FUSE_DEFAULT_BLKSIZE 512
  53
  54 /** Maximum number of outstanding background requests */
  55 #define FUSE_DEFAULT_MAX_BACKGROUND 12
  56
  57 /** Congestion starts at 75% of maximum */
  58 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
  59
  60 struct fuse_mount_data {
  61         int fd;
  62         unsigned rootmode;
  63         unsigned user_id;
  64         unsigned group_id;
  65         unsigned fd_present:1;
  66         unsigned rootmode_present:1;
  67         unsigned user_id_present:1;
  68         unsigned group_id_present:1;
  69         unsigned flags;
  70         unsigned max_read;
  71         unsigned blksize;
  72 };
  73
  74 static struct inode *fuse_alloc_inode(struct super_block *sb)
  75 {
  76         struct inode *inode;
  77         struct fuse_inode *fi;
  78
  79         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  80         if (!inode)
  81                 return NULL;
  82
  83         fi = get_fuse_inode(inode);
  84         fi->i_time = 0;
  85         fi->nodeid = 0;
  86         fi->nlookup = 0;
  87         fi->attr_version = 0;
  88         fi->writectr = 0;
  89         INIT_LIST_HEAD(&fi->write_files);
  90         INIT_LIST_HEAD(&fi->queued_writes);
  91         INIT_LIST_HEAD(&fi->writepages);
  92         init_waitqueue_head(&fi->page_waitq);
  93         fi->forget_req = fuse_request_alloc();
  94         if (!fi->forget_req) {
  95                 kmem_cache_free(fuse_inode_cachep, inode);
  96                 return NULL;
  97         }
  98
  99         return inode;
 100 }
 101
 102 static void fuse_destroy_inode(struct inode *inode)
 103 {
 104         struct fuse_inode *fi = get_fuse_inode(inode);
 105         BUG_ON(!list_empty(&fi->write_files));
 106         BUG_ON(!list_empty(&fi->queued_writes));
 107         if (fi->forget_req)
 108                 fuse_request_free(fi->forget_req);
 109         kmem_cache_free(fuse_inode_cachep, inode);
 110 }
 111
 112 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 113                       u64 nodeid, u64 nlookup)
 114 {
 115         struct fuse_forget_in *inarg = &req->misc.forget_in;
 116         inarg->nlookup = nlookup;
 117         req->in.h.opcode = FUSE_FORGET;
 118         req->in.h.nodeid = nodeid;
 119         req->in.numargs = 1;
 120         req->in.args[0].size = sizeof(struct fuse_forget_in);
 121         req->in.args[0].value = inarg;
 122         fuse_request_send_noreply(fc, req);
 123 }
 124
 125 static void fuse_evict_inode(struct inode *inode)
 126 {
 127         truncate_inode_pages(&inode->i_data, 0);
 128         end_writeback(inode);
 129         if (inode->i_sb->s_flags & MS_ACTIVE) {
 130                 struct fuse_conn *fc = get_fuse_conn(inode);
 131                 struct fuse_inode *fi = get_fuse_inode(inode);
 132                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
 133                 fi->forget_req = NULL;
 134         }
 135 }
 136
 137 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 138 {
 139         if (*flags & MS_MANDLOCK)
 140                 return -EINVAL;
 141
 142         return 0;
 143 }
 144
 145 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 146                                    u64 attr_valid)
 147 {
 148         struct fuse_conn *fc = get_fuse_conn(inode);
 149         struct fuse_inode *fi = get_fuse_inode(inode);
 150
 151         fi->attr_version = ++fc->attr_version;
 152         fi->i_time = attr_valid;
 153
 154         inode->i_ino     = attr->ino;
 155         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 156         inode->i_nlink   = attr->nlink;
 157         inode->i_uid     = attr->uid;
 158         inode->i_gid     = attr->gid;
 159         inode->i_blocks  = attr->blocks;
 160         inode->i_atime.tv_sec   = attr->atime;
 161         inode->i_atime.tv_nsec  = attr->atimensec;
 162         inode->i_mtime.tv_sec   = attr->mtime;
 163         inode->i_mtime.tv_nsec  = attr->mtimensec;
 164         inode->i_ctime.tv_sec   = attr->ctime;
 165         inode->i_ctime.tv_nsec  = attr->ctimensec;
 166
 167         if (attr->blksize != 0)
 168                 inode->i_blkbits = ilog2(attr->blksize);
 169         else
 170                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 171
 172         /*
 173          * Don't set the sticky bit in i_mode, unless we want the VFS
 174          * to check permissions.  This prevents failures due to the
 175          * check in may_delete().
 176          */
 177         fi->orig_i_mode = inode->i_mode;
 178         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
 179                 inode->i_mode &= ~S_ISVTX;
 180 }
 181
 182 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 183                             u64 attr_valid, u64 attr_version)
 184 {
 185         struct fuse_conn *fc = get_fuse_conn(inode);
 186         struct fuse_inode *fi = get_fuse_inode(inode);
 187         loff_t oldsize;
 188
 189         spin_lock(&fc->lock);
 190         if (attr_version != 0 && fi->attr_version > attr_version) {
 191                 spin_unlock(&fc->lock);
 192                 return;
 193         }
 194
 195         fuse_change_attributes_common(inode, attr, attr_valid);
 196
 197         oldsize = inode->i_size;
 198         i_size_write(inode, attr->size);
 199         spin_unlock(&fc->lock);
 200
 201         if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
 202                 truncate_pagecache(inode, oldsize, attr->size);
 203                 invalidate_inode_pages2(inode->i_mapping);
 204         }
 205 }
 206
 207 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 208 {
 209         inode->i_mode = attr->mode & S_IFMT;
 210         inode->i_size = attr->size;
 211         if (S_ISREG(inode->i_mode)) {
 212                 fuse_init_common(inode);
 213                 fuse_init_file_inode(inode);
 214         } else if (S_ISDIR(inode->i_mode))
 215                 fuse_init_dir(inode);
 216         else if (S_ISLNK(inode->i_mode))
 217                 fuse_init_symlink(inode);
 218         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 219                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 220                 fuse_init_common(inode);
 221                 init_special_inode(inode, inode->i_mode,
 222                                    new_decode_dev(attr->rdev));
 223         } else
 224                 BUG();
 225 }
 226
 227 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 228 {
 229         u64 nodeid = *(u64 *) _nodeidp;
 230         if (get_node_id(inode) == nodeid)
 231                 return 1;
 232         else
 233                 return 0;
 234 }
 235
 236 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 237 {
 238         u64 nodeid = *(u64 *) _nodeidp;
 239         get_fuse_inode(inode)->nodeid = nodeid;
 240         return 0;
 241 }
 242
 243 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 244                         int generation, struct fuse_attr *attr,
 245                         u64 attr_valid, u64 attr_version)
 246 {
 247         struct inode *inode;
 248         struct fuse_inode *fi;
 249         struct fuse_conn *fc = get_fuse_conn_super(sb);
 250
 251  retry:
 252         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 253         if (!inode)
 254                 return NULL;
 255
 256         if ((inode->i_state & I_NEW)) {
 257                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
 258                 inode->i_generation = generation;
 259                 inode->i_data.backing_dev_info = &fc->bdi;
 260                 fuse_init_inode(inode, attr);
 261                 unlock_new_inode(inode);
 262         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 263                 /* Inode has changed type, any I/O on the old should fail */
 264                 make_bad_inode(inode);
 265                 iput(inode);
 266                 goto retry;
 267         }
 268
 269         fi = get_fuse_inode(inode);
 270         spin_lock(&fc->lock);
 271         fi->nlookup++;
 272         spin_unlock(&fc->lock);
 273         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 274
 275         return inode;
 276 }
 277
 278 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 279                              loff_t offset, loff_t len)
 280 {
 281         struct inode *inode;
 282         pgoff_t pg_start;
 283         pgoff_t pg_end;
 284
 285         inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
 286         if (!inode)
 287                 return -ENOENT;
 288
 289         fuse_invalidate_attr(inode);
 290         if (offset >= 0) {
 291                 pg_start = offset >> PAGE_CACHE_SHIFT;
 292                 if (len <= 0)
 293                         pg_end = -1;
 294                 else
 295                         pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
 296                 invalidate_inode_pages2_range(inode->i_mapping,
 297                                               pg_start, pg_end);
 298         }
 299         iput(inode);
 300         return 0;
 301 }
 302
 303 static void fuse_umount_begin(struct super_block *sb)
 304 {
 305         fuse_abort_conn(get_fuse_conn_super(sb));
 306 }
 307
 308 static void fuse_send_destroy(struct fuse_conn *fc)
 309 {
 310         struct fuse_req *req = fc->destroy_req;
 311         if (req && fc->conn_init) {
 312                 fc->destroy_req = NULL;
 313                 req->in.h.opcode = FUSE_DESTROY;
 314                 req->force = 1;
 315                 fuse_request_send(fc, req);
 316                 fuse_put_request(fc, req);
 317         }
 318 }
 319
 320 static void fuse_bdi_destroy(struct fuse_conn *fc)
 321 {
 322         if (fc->bdi_initialized)
 323                 bdi_destroy(&fc->bdi);
 324 }
 325
 326 void fuse_conn_kill(struct fuse_conn *fc)
 327 {
 328         spin_lock(&fc->lock);
 329         fc->connected = 0;
 330         fc->blocked = 0;
 331         spin_unlock(&fc->lock);
 332         /* Flush all readers on this fs */
 333         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 334         wake_up_all(&fc->waitq);
 335         wake_up_all(&fc->blocked_waitq);
 336         wake_up_all(&fc->reserved_req_waitq);
 337         mutex_lock(&fuse_mutex);
 338         list_del(&fc->entry);
 339         fuse_ctl_remove_conn(fc);
 340         mutex_unlock(&fuse_mutex);
 341         fuse_bdi_destroy(fc);
 342 }
 343 EXPORT_SYMBOL_GPL(fuse_conn_kill);
 344
 345 static void fuse_put_super(struct super_block *sb)
 346 {
 347         struct fuse_conn *fc = get_fuse_conn_super(sb);
 348
 349         fuse_send_destroy(fc);
 350         fuse_conn_kill(fc);
 351         fuse_conn_put(fc);
 352 }
 353
 354 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 355 {
 356         stbuf->f_type    = FUSE_SUPER_MAGIC;
 357         stbuf->f_bsize   = attr->bsize;
 358         stbuf->f_frsize  = attr->frsize;
 359         stbuf->f_blocks  = attr->blocks;
 360         stbuf->f_bfree   = attr->bfree;
 361         stbuf->f_bavail  = attr->bavail;
 362         stbuf->f_files   = attr->files;
 363         stbuf->f_ffree   = attr->ffree;
 364         stbuf->f_namelen = attr->namelen;
 365         /* fsid is left zero */
 366 }
 367
 368 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 369 {
 370         struct super_block *sb = dentry->d_sb;
 371         struct fuse_conn *fc = get_fuse_conn_super(sb);
 372         struct fuse_req *req;
 373         struct fuse_statfs_out outarg;
 374         int err;
 375
 376         if (!fuse_allow_task(fc, current)) {
 377                 buf->f_type = FUSE_SUPER_MAGIC;
 378                 return 0;
 379         }
 380
 381         req = fuse_get_req(fc);
 382         if (IS_ERR(req))
 383                 return PTR_ERR(req);
 384
 385         memset(&outarg, 0, sizeof(outarg));
 386         req->in.numargs = 0;
 387         req->in.h.opcode = FUSE_STATFS;
 388         req->in.h.nodeid = get_node_id(dentry->d_inode);
 389         req->out.numargs = 1;
 390         req->out.args[0].size =
 391                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 392         req->out.args[0].value = &outarg;
 393         fuse_request_send(fc, req);
 394         err = req->out.h.error;
 395         if (!err)
 396                 convert_fuse_statfs(buf, &outarg.st);
 397         fuse_put_request(fc, req);
 398         return err;
 399 }
 400
 401 enum {
 402         OPT_FD,
 403         OPT_ROOTMODE,
 404         OPT_USER_ID,
 405         OPT_GROUP_ID,
 406         OPT_DEFAULT_PERMISSIONS,
 407         OPT_ALLOW_OTHER,
 408         OPT_MAX_READ,
 409         OPT_BLKSIZE,
 410         OPT_ERR
 411 };
 412
 413 static const match_table_t tokens = {
 414         {OPT_FD,                        "fd=%u"},
 415         {OPT_ROOTMODE,                  "rootmode=%o"},
 416         {OPT_USER_ID,                   "user_id=%u"},
 417         {OPT_GROUP_ID,                  "group_id=%u"},
 418         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 419         {OPT_ALLOW_OTHER,               "allow_other"},
 420         {OPT_MAX_READ,                  "max_read=%u"},
 421         {OPT_BLKSIZE,                   "blksize=%u"},
 422         {OPT_ERR,                       NULL}
 423 };
 424
 425 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 426 {
 427         char *p;
 428         memset(d, 0, sizeof(struct fuse_mount_data));
 429         d->max_read = ~0;
 430         d->blksize = FUSE_DEFAULT_BLKSIZE;
 431
 432         while ((p = strsep(&opt, ",")) != NULL) {
 433                 int token;
 434                 int value;
 435                 substring_t args[MAX_OPT_ARGS];
 436                 if (!*p)
 437                         continue;
 438
 439                 token = match_token(p, tokens, args);
 440                 switch (token) {
 441                 case OPT_FD:
 442                         if (match_int(&args[0], &value))
 443                                 return 0;
 444                         d->fd = value;
 445                         d->fd_present = 1;
 446                         break;
 447
 448                 case OPT_ROOTMODE:
 449                         if (match_octal(&args[0], &value))
 450                                 return 0;
 451                         if (!fuse_valid_type(value))
 452                                 return 0;
 453                         d->rootmode = value;
 454                         d->rootmode_present = 1;
 455                         break;
 456
 457                 case OPT_USER_ID:
 458                         if (match_int(&args[0], &value))
 459                                 return 0;
 460                         d->user_id = value;
 461                         d->user_id_present = 1;
 462                         break;
 463
 464                 case OPT_GROUP_ID:
 465                         if (match_int(&args[0], &value))
 466                                 return 0;
 467                         d->group_id = value;
 468                         d->group_id_present = 1;
 469                         break;
 470
 471                 case OPT_DEFAULT_PERMISSIONS:
 472                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 473                         break;
 474
 475                 case OPT_ALLOW_OTHER:
 476                         d->flags |= FUSE_ALLOW_OTHER;
 477                         break;
 478
 479                 case OPT_MAX_READ:
 480                         if (match_int(&args[0], &value))
 481                                 return 0;
 482                         d->max_read = value;
 483                         break;
 484
 485                 case OPT_BLKSIZE:
 486                         if (!is_bdev || match_int(&args[0], &value))
 487                                 return 0;
 488                         d->blksize = value;
 489                         break;
 490
 491                 default:
 492                         return 0;
 493                 }
 494         }
 495
 496         if (!d->fd_present || !d->rootmode_present ||
 497             !d->user_id_present || !d->group_id_present)
 498                 return 0;
 499
 500         return 1;
 501 }
 502
 503 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 504 {
 505         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 506
 507         seq_printf(m, ",user_id=%u", fc->user_id);
 508         seq_printf(m, ",group_id=%u", fc->group_id);
 509         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 510                 seq_puts(m, ",default_permissions");
 511         if (fc->flags & FUSE_ALLOW_OTHER)
 512                 seq_puts(m, ",allow_other");
 513         if (fc->max_read != ~0)
 514                 seq_printf(m, ",max_read=%u", fc->max_read);
 515         if (mnt->mnt_sb->s_bdev &&
 516             mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 517                 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
 518         return 0;
 519 }
 520
 521 void fuse_conn_init(struct fuse_conn *fc)
 522 {
 523         memset(fc, 0, sizeof(*fc));
 524         spin_lock_init(&fc->lock);
 525         mutex_init(&fc->inst_mutex);
 526         init_rwsem(&fc->killsb);
 527         atomic_set(&fc->count, 1);
 528         init_waitqueue_head(&fc->waitq);
 529         init_waitqueue_head(&fc->blocked_waitq);
 530         init_waitqueue_head(&fc->reserved_req_waitq);
 531         INIT_LIST_HEAD(&fc->pending);
 532         INIT_LIST_HEAD(&fc->processing);
 533         INIT_LIST_HEAD(&fc->io);
 534         INIT_LIST_HEAD(&fc->interrupts);
 535         INIT_LIST_HEAD(&fc->bg_queue);
 536         INIT_LIST_HEAD(&fc->entry);
 537         atomic_set(&fc->num_waiting, 0);
 538         fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 539         fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 540         fc->khctr = 0;
 541         fc->polled_files = RB_ROOT;
 542         fc->reqctr = 0;
 543         fc->blocked = 1;
 544         fc->attr_version = 1;
 545         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 546 }
 547 EXPORT_SYMBOL_GPL(fuse_conn_init);
 548
 549 void fuse_conn_put(struct fuse_conn *fc)
 550 {
 551         if (atomic_dec_and_test(&fc->count)) {
 552                 if (fc->destroy_req)
 553                         fuse_request_free(fc->destroy_req);
 554                 mutex_destroy(&fc->inst_mutex);
 555                 fc->release(fc);
 556         }
 557 }
 558 EXPORT_SYMBOL_GPL(fuse_conn_put);
 559
 560 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 561 {
 562         atomic_inc(&fc->count);
 563         return fc;
 564 }
 565 EXPORT_SYMBOL_GPL(fuse_conn_get);
 566
 567 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 568 {
 569         struct fuse_attr attr;
 570         memset(&attr, 0, sizeof(attr));
 571
 572         attr.mode = mode;
 573         attr.ino = FUSE_ROOT_ID;
 574         attr.nlink = 1;
 575         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 576 }
 577
 578 struct fuse_inode_handle {
 579         u64 nodeid;
 580         u32 generation;
 581 };
 582
 583 static struct dentry *fuse_get_dentry(struct super_block *sb,
 584                                       struct fuse_inode_handle *handle)
 585 {
 586         struct fuse_conn *fc = get_fuse_conn_super(sb);
 587         struct inode *inode;
 588         struct dentry *entry;
 589         int err = -ESTALE;
 590
 591         if (handle->nodeid == 0)
 592                 goto out_err;
 593
 594         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 595         if (!inode) {
 596                 struct fuse_entry_out outarg;
 597                 struct qstr name;
 598
 599                 if (!fc->export_support)
 600                         goto out_err;
 601
 602                 name.len = 1;
 603                 name.name = ".";
 604                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 605                                        &inode);
 606                 if (err && err != -ENOENT)
 607                         goto out_err;
 608                 if (err || !inode) {
 609                         err = -ESTALE;
 610                         goto out_err;
 611                 }
 612                 err = -EIO;
 613                 if (get_node_id(inode) != handle->nodeid)
 614                         goto out_iput;
 615         }
 616         err = -ESTALE;
 617         if (inode->i_generation != handle->generation)
 618                 goto out_iput;
 619
 620         entry = d_obtain_alias(inode);
 621         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) {
 622                 entry->d_op = &fuse_dentry_operations;
 623                 fuse_invalidate_entry_cache(entry);
 624         }
 625
 626         return entry;
 627
 628  out_iput:
 629         iput(inode);
 630  out_err:
 631         return ERR_PTR(err);
 632 }
 633
 634 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
 635                            int connectable)
 636 {
 637         struct inode *inode = dentry->d_inode;
 638         bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
 639         int len = encode_parent ? 6 : 3;
 640         u64 nodeid;
 641         u32 generation;
 642
 643         if (*max_len < len)
 644                 return  255;
 645
 646         nodeid = get_fuse_inode(inode)->nodeid;
 647         generation = inode->i_generation;
 648
 649         fh[0] = (u32)(nodeid >> 32);
 650         fh[1] = (u32)(nodeid & 0xffffffff);
 651         fh[2] = generation;
 652
 653         if (encode_parent) {
 654                 struct inode *parent;
 655
 656                 spin_lock(&dentry->d_lock);
 657                 parent = dentry->d_parent->d_inode;
 658                 nodeid = get_fuse_inode(parent)->nodeid;
 659                 generation = parent->i_generation;
 660                 spin_unlock(&dentry->d_lock);
 661
 662                 fh[3] = (u32)(nodeid >> 32);
 663                 fh[4] = (u32)(nodeid & 0xffffffff);
 664                 fh[5] = generation;
 665         }
 666
 667         *max_len = len;
 668         return encode_parent ? 0x82 : 0x81;
 669 }
 670
 671 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 672                 struct fid *fid, int fh_len, int fh_type)
 673 {
 674         struct fuse_inode_handle handle;
 675
 676         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 677                 return NULL;
 678
 679         handle.nodeid = (u64) fid->raw[0] << 32;
 680         handle.nodeid |= (u64) fid->raw[1];
 681         handle.generation = fid->raw[2];
 682         return fuse_get_dentry(sb, &handle);
 683 }
 684
 685 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 686                 struct fid *fid, int fh_len, int fh_type)
 687 {
 688         struct fuse_inode_handle parent;
 689
 690         if (fh_type != 0x82 || fh_len < 6)
 691                 return NULL;
 692
 693         parent.nodeid = (u64) fid->raw[3] << 32;
 694         parent.nodeid |= (u64) fid->raw[4];
 695         parent.generation = fid->raw[5];
 696         return fuse_get_dentry(sb, &parent);
 697 }
 698
 699 static struct dentry *fuse_get_parent(struct dentry *child)
 700 {
 701         struct inode *child_inode = child->d_inode;
 702         struct fuse_conn *fc = get_fuse_conn(child_inode);
 703         struct inode *inode;
 704         struct dentry *parent;
 705         struct fuse_entry_out outarg;
 706         struct qstr name;
 707         int err;
 708
 709         if (!fc->export_support)
 710                 return ERR_PTR(-ESTALE);
 711
 712         name.len = 2;
 713         name.name = "..";
 714         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 715                                &name, &outarg, &inode);
 716         if (err) {
 717                 if (err == -ENOENT)
 718                         return ERR_PTR(-ESTALE);
 719                 return ERR_PTR(err);
 720         }
 721
 722         parent = d_obtain_alias(inode);
 723         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) {
 724                 parent->d_op = &fuse_dentry_operations;
 725                 fuse_invalidate_entry_cache(parent);
 726         }
 727
 728         return parent;
 729 }
 730
 731 static const struct export_operations fuse_export_operations = {
 732         .fh_to_dentry   = fuse_fh_to_dentry,
 733         .fh_to_parent   = fuse_fh_to_parent,
 734         .encode_fh      = fuse_encode_fh,
 735         .get_parent     = fuse_get_parent,
 736 };
 737
 738 static const struct super_operations fuse_super_operations = {
 739         .alloc_inode    = fuse_alloc_inode,
 740         .destroy_inode  = fuse_destroy_inode,
 741         .evict_inode    = fuse_evict_inode,
 742         .drop_inode     = generic_delete_inode,
 743         .remount_fs     = fuse_remount_fs,
 744         .put_super      = fuse_put_super,
 745         .umount_begin   = fuse_umount_begin,
 746         .statfs         = fuse_statfs,
 747         .show_options   = fuse_show_options,
 748 };
 749
 750 static void sanitize_global_limit(unsigned *limit)
 751 {
 752         if (*limit == 0)
 753                 *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
 754                          sizeof(struct fuse_req);
 755
 756         if (*limit >= 1 << 16)
 757                 *limit = (1 << 16) - 1;
 758 }
 759
 760 static int set_global_limit(const char *val, struct kernel_param *kp)
 761 {
 762         int rv;
 763
 764         rv = param_set_uint(val, kp);
 765         if (rv)
 766                 return rv;
 767
 768         sanitize_global_limit((unsigned *)kp->arg);
 769
 770         return 0;
 771 }
 772
 773 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 774 {
 775         int cap_sys_admin = capable(CAP_SYS_ADMIN);
 776
 777         if (arg->minor < 13)
 778                 return;
 779
 780         sanitize_global_limit(&max_user_bgreq);
 781         sanitize_global_limit(&max_user_congthresh);
 782
 783         if (arg->max_background) {
 784                 fc->max_background = arg->max_background;
 785
 786                 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 787                         fc->max_background = max_user_bgreq;
 788         }
 789         if (arg->congestion_threshold) {
 790                 fc->congestion_threshold = arg->congestion_threshold;
 791
 792                 if (!cap_sys_admin &&
 793                     fc->congestion_threshold > max_user_congthresh)
 794                         fc->congestion_threshold = max_user_congthresh;
 795         }
 796 }
 797
 798 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 799 {
 800         struct fuse_init_out *arg = &req->misc.init_out;
 801
 802         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 803                 fc->conn_error = 1;
 804         else {
 805                 unsigned long ra_pages;
 806
 807                 process_init_limits(fc, arg);
 808
 809                 if (arg->minor >= 6) {
 810                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 811                         if (arg->flags & FUSE_ASYNC_READ)
 812                                 fc->async_read = 1;
 813                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 814                                 fc->no_lock = 1;
 815                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 816                                 fc->atomic_o_trunc = 1;
 817                         if (arg->minor >= 9) {
 818                                 /* LOOKUP has dependency on proto version */
 819                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 820                                         fc->export_support = 1;
 821                         }
 822                         if (arg->flags & FUSE_BIG_WRITES)
 823                                 fc->big_writes = 1;
 824                         if (arg->flags & FUSE_DONT_MASK)
 825                                 fc->dont_mask = 1;
 826                 } else {
 827                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 828                         fc->no_lock = 1;
 829                 }
 830
 831                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 832                 fc->minor = arg->minor;
 833                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 834                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
 835                 fc->conn_init = 1;
 836         }
 837         fc->blocked = 0;
 838         wake_up_all(&fc->blocked_waitq);
 839 }
 840
 841 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 842 {
 843         struct fuse_init_in *arg = &req->misc.init_in;
 844
 845         arg->major = FUSE_KERNEL_VERSION;
 846         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 847         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 848         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 849                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK;
 850         req->in.h.opcode = FUSE_INIT;
 851         req->in.numargs = 1;
 852         req->in.args[0].size = sizeof(*arg);
 853         req->in.args[0].value = arg;
 854         req->out.numargs = 1;
 855         /* Variable length argument used for backward compatibility
 856            with interface version < 7.5.  Rest of init_out is zeroed
 857            by do_get_request(), so a short reply is not a problem */
 858         req->out.argvar = 1;
 859         req->out.args[0].size = sizeof(struct fuse_init_out);
 860         req->out.args[0].value = &req->misc.init_out;
 861         req->end = process_init_reply;
 862         fuse_request_send_background(fc, req);
 863 }
 864
 865 static void fuse_free_conn(struct fuse_conn *fc)
 866 {
 867         kfree(fc);
 868 }
 869
 870 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 871 {
 872         int err;
 873
 874         fc->bdi.name = "fuse";
 875         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 876         fc->bdi.unplug_io_fn = default_unplug_io_fn;
 877         /* fuse does it's own writeback accounting */
 878         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
 879
 880         err = bdi_init(&fc->bdi);
 881         if (err)
 882                 return err;
 883
 884         fc->bdi_initialized = 1;
 885
 886         if (sb->s_bdev) {
 887                 err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
 888                                     MAJOR(fc->dev), MINOR(fc->dev));
 889         } else {
 890                 err = bdi_register_dev(&fc->bdi, fc->dev);
 891         }
 892
 893         if (err)
 894                 return err;
 895
 896         /*
 897          * For a single fuse filesystem use max 1% of dirty +
 898          * writeback threshold.
 899          *
 900          * This gives about 1M of write buffer for memory maps on a
 901          * machine with 1G and 10% dirty_ratio, which should be more
 902          * than enough.
 903          *
 904          * Privileged users can raise it by writing to
 905          *
 906          *    /sys/class/bdi/<bdi>/max_ratio
 907          */
 908         bdi_set_max_ratio(&fc->bdi, 1);
 909
 910         return 0;
 911 }
 912
 913 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 914 {
 915         struct fuse_conn *fc;
 916         struct inode *root;
 917         struct fuse_mount_data d;
 918         struct file *file;
 919         struct dentry *root_dentry;
 920         struct fuse_req *init_req;
 921         int err;
 922         int is_bdev = sb->s_bdev != NULL;
 923
 924         err = -EINVAL;
 925         if (sb->s_flags & MS_MANDLOCK)
 926                 goto err;
 927
 928         if (!parse_fuse_opt((char *) data, &d, is_bdev))
 929                 goto err;
 930
 931         if (is_bdev) {
 932 #ifdef CONFIG_BLOCK
 933                 err = -EINVAL;
 934                 if (!sb_set_blocksize(sb, d.blksize))
 935                         goto err;
 936 #endif
 937         } else {
 938                 sb->s_blocksize = PAGE_CACHE_SIZE;
 939                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 940         }
 941         sb->s_magic = FUSE_SUPER_MAGIC;
 942         sb->s_op = &fuse_super_operations;
 943         sb->s_maxbytes = MAX_LFS_FILESIZE;
 944         sb->s_export_op = &fuse_export_operations;
 945
 946         file = fget(d.fd);
 947         err = -EINVAL;
 948         if (!file)
 949                 goto err;
 950
 951         if (file->f_op != &fuse_dev_operations)
 952                 goto err_fput;
 953
 954         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
 955         err = -ENOMEM;
 956         if (!fc)
 957                 goto err_fput;
 958
 959         fuse_conn_init(fc);
 960
 961         fc->dev = sb->s_dev;
 962         fc->sb = sb;
 963         err = fuse_bdi_init(fc, sb);
 964         if (err)
 965                 goto err_put_conn;
 966
 967         sb->s_bdi = &fc->bdi;
 968
 969         /* Handle umasking inside the fuse code */
 970         if (sb->s_flags & MS_POSIXACL)
 971                 fc->dont_mask = 1;
 972         sb->s_flags |= MS_POSIXACL;
 973
 974         fc->release = fuse_free_conn;
 975         fc->flags = d.flags;
 976         fc->user_id = d.user_id;
 977         fc->group_id = d.group_id;
 978         fc->max_read = max_t(unsigned, 4096, d.max_read);
 979
 980         /* Used by get_root_inode() */
 981         sb->s_fs_info = fc;
 982
 983         err = -ENOMEM;
 984         root = fuse_get_root_inode(sb, d.rootmode);
 985         if (!root)
 986                 goto err_put_conn;
 987
 988         root_dentry = d_alloc_root(root);
 989         if (!root_dentry) {
 990                 iput(root);
 991                 goto err_put_conn;
 992         }
 993
 994         init_req = fuse_request_alloc();
 995         if (!init_req)
 996                 goto err_put_root;
 997
 998         if (is_bdev) {
 999                 fc->destroy_req = fuse_request_alloc();
1000                 if (!fc->destroy_req)
1001                         goto err_free_init_req;
1002         }
1003
1004         mutex_lock(&fuse_mutex);
1005         err = -EINVAL;
1006         if (file->private_data)
1007                 goto err_unlock;
1008
1009         err = fuse_ctl_add_conn(fc);
1010         if (err)
1011                 goto err_unlock;
1012
1013         list_add_tail(&fc->entry, &fuse_conn_list);
1014         sb->s_root = root_dentry;
1015         fc->connected = 1;
1016         file->private_data = fuse_conn_get(fc);
1017         mutex_unlock(&fuse_mutex);
1018         /*
1019          * atomic_dec_and_test() in fput() provides the necessary
1020          * memory barrier for file->private_data to be visible on all
1021          * CPUs after this
1022          */
1023         fput(file);
1024
1025         fuse_send_init(fc, init_req);
1026
1027         return 0;
1028
1029  err_unlock:
1030         mutex_unlock(&fuse_mutex);
1031  err_free_init_req:
1032         fuse_request_free(init_req);
1033  err_put_root:
1034         dput(root_dentry);
1035  err_put_conn:
1036         fuse_bdi_destroy(fc);
1037         fuse_conn_put(fc);
1038  err_fput:
1039         fput(file);
1040  err:
1041         return err;
1042 }
1043
1044 static int fuse_get_sb(struct file_system_type *fs_type,
1045                        int flags, const char *dev_name,
1046                        void *raw_data, struct vfsmount *mnt)
1047 {
1048         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
1049 }
1050
1051 static void fuse_kill_sb_anon(struct super_block *sb)
1052 {
1053         struct fuse_conn *fc = get_fuse_conn_super(sb);
1054
1055         if (fc) {
1056                 down_write(&fc->killsb);
1057                 fc->sb = NULL;
1058                 up_write(&fc->killsb);
1059         }
1060
1061         kill_anon_super(sb);
1062 }
1063
1064 static struct file_system_type fuse_fs_type = {
1065         .owner          = THIS_MODULE,
1066         .name           = "fuse",
1067         .fs_flags       = FS_HAS_SUBTYPE,
1068         .get_sb         = fuse_get_sb,
1069         .kill_sb        = fuse_kill_sb_anon,
1070 };
1071
1072 #ifdef CONFIG_BLOCK
1073 static int fuse_get_sb_blk(struct file_system_type *fs_type,
1074                            int flags, const char *dev_name,
1075                            void *raw_data, struct vfsmount *mnt)
1076 {
1077         return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
1078                            mnt);
1079 }
1080
1081 static void fuse_kill_sb_blk(struct super_block *sb)
1082 {
1083         struct fuse_conn *fc = get_fuse_conn_super(sb);
1084
1085         if (fc) {
1086                 down_write(&fc->killsb);
1087                 fc->sb = NULL;
1088                 up_write(&fc->killsb);
1089         }
1090
1091         kill_block_super(sb);
1092 }
1093
1094 static struct file_system_type fuseblk_fs_type = {
1095         .owner          = THIS_MODULE,
1096         .name           = "fuseblk",
1097         .get_sb         = fuse_get_sb_blk,
1098         .kill_sb        = fuse_kill_sb_blk,
1099         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1100 };
1101
1102 static inline int register_fuseblk(void)
1103 {
1104         return register_filesystem(&fuseblk_fs_type);
1105 }
1106
1107 static inline void unregister_fuseblk(void)
1108 {
1109         unregister_filesystem(&fuseblk_fs_type);
1110 }
1111 #else
1112 static inline int register_fuseblk(void)
1113 {
1114         return 0;
1115 }
1116
1117 static inline void unregister_fuseblk(void)
1118 {
1119 }
1120 #endif
1121
1122 static void fuse_inode_init_once(void *foo)
1123 {
1124         struct inode *inode = foo;
1125
1126         inode_init_once(inode);
1127 }
1128
1129 static int __init fuse_fs_init(void)
1130 {
1131         int err;
1132
1133         err = register_filesystem(&fuse_fs_type);
1134         if (err)
1135                 goto out;
1136
1137         err = register_fuseblk();
1138         if (err)
1139                 goto out_unreg;
1140
1141         fuse_inode_cachep = kmem_cache_create("fuse_inode",
1142                                               sizeof(struct fuse_inode),
1143                                               0, SLAB_HWCACHE_ALIGN,
1144                                               fuse_inode_init_once);
1145         err = -ENOMEM;
1146         if (!fuse_inode_cachep)
1147                 goto out_unreg2;
1148
1149         return 0;
1150
1151  out_unreg2:
1152         unregister_fuseblk();
1153  out_unreg:
1154         unregister_filesystem(&fuse_fs_type);
1155  out:
1156         return err;
1157 }
1158
1159 static void fuse_fs_cleanup(void)
1160 {
1161         unregister_filesystem(&fuse_fs_type);
1162         unregister_fuseblk();
1163         kmem_cache_destroy(fuse_inode_cachep);
1164 }
1165
1166 static struct kobject *fuse_kobj;
1167 static struct kobject *connections_kobj;
1168
1169 static int fuse_sysfs_init(void)
1170 {
1171         int err;
1172
1173         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1174         if (!fuse_kobj) {
1175                 err = -ENOMEM;
1176                 goto out_err;
1177         }
1178
1179         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1180         if (!connections_kobj) {
1181                 err = -ENOMEM;
1182                 goto out_fuse_unregister;
1183         }
1184
1185         return 0;
1186
1187  out_fuse_unregister:
1188         kobject_put(fuse_kobj);
1189  out_err:
1190         return err;
1191 }
1192
1193 static void fuse_sysfs_cleanup(void)
1194 {
1195         kobject_put(connections_kobj);
1196         kobject_put(fuse_kobj);
1197 }
1198
1199 static int __init fuse_init(void)
1200 {
1201         int res;
1202
1203         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1204                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1205
1206         INIT_LIST_HEAD(&fuse_conn_list);
1207         res = fuse_fs_init();
1208         if (res)
1209                 goto err;
1210
1211         res = fuse_dev_init();
1212         if (res)
1213                 goto err_fs_cleanup;
1214
1215         res = fuse_sysfs_init();
1216         if (res)
1217                 goto err_dev_cleanup;
1218
1219         res = fuse_ctl_init();
1220         if (res)
1221                 goto err_sysfs_cleanup;
1222
1223         sanitize_global_limit(&max_user_bgreq);
1224         sanitize_global_limit(&max_user_congthresh);
1225
1226         return 0;
1227
1228  err_sysfs_cleanup:
1229         fuse_sysfs_cleanup();
1230  err_dev_cleanup:
1231         fuse_dev_cleanup();
1232  err_fs_cleanup:
1233         fuse_fs_cleanup();
1234  err:
1235         return res;
1236 }
1237
1238 static void __exit fuse_exit(void)
1239 {
1240         printk(KERN_DEBUG "fuse exit\n");
1241
1242         fuse_ctl_cleanup();
1243         fuse_sysfs_cleanup();
1244         fuse_fs_cleanup();
1245         fuse_dev_cleanup();
1246 }
1247
1248 module_init(fuse_init);
1249 module_exit(fuse_exit);