linux/fs/fuse/inode.c
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   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
  24MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  25MODULE_DESCRIPTION("Filesystem in Userspace");
  26MODULE_LICENSE("GPL");
  27
  28static struct kmem_cache *fuse_inode_cachep;
  29struct list_head fuse_conn_list;
  30DEFINE_MUTEX(fuse_mutex);
  31
  32static int set_global_limit(const char *val, struct kernel_param *kp);
  33
  34unsigned max_user_bgreq;
  35module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
  36                  &max_user_bgreq, 0644);
  37__MODULE_PARM_TYPE(max_user_bgreq, "uint");
  38MODULE_PARM_DESC(max_user_bgreq,
  39 "Global limit for the maximum number of backgrounded requests an "
  40 "unprivileged user can set");
  41
  42unsigned max_user_congthresh;
  43module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
  44                  &max_user_congthresh, 0644);
  45__MODULE_PARM_TYPE(max_user_congthresh, "uint");
  46MODULE_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
  60struct 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
  74struct fuse_forget_link *fuse_alloc_forget(void)
  75{
  76        return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
  77}
  78
  79static struct inode *fuse_alloc_inode(struct super_block *sb)
  80{
  81        struct inode *inode;
  82        struct fuse_inode *fi;
  83
  84        inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  85        if (!inode)
  86                return NULL;
  87
  88        fi = get_fuse_inode(inode);
  89        fi->i_time = 0;
  90        fi->nodeid = 0;
  91        fi->nlookup = 0;
  92        fi->attr_version = 0;
  93        fi->writectr = 0;
  94        fi->orig_ino = 0;
  95        INIT_LIST_HEAD(&fi->write_files);
  96        INIT_LIST_HEAD(&fi->queued_writes);
  97        INIT_LIST_HEAD(&fi->writepages);
  98        init_waitqueue_head(&fi->page_waitq);
  99        fi->forget = fuse_alloc_forget();
 100        if (!fi->forget) {
 101                kmem_cache_free(fuse_inode_cachep, inode);
 102                return NULL;
 103        }
 104
 105        return inode;
 106}
 107
 108static void fuse_i_callback(struct rcu_head *head)
 109{
 110        struct inode *inode = container_of(head, struct inode, i_rcu);
 111        kmem_cache_free(fuse_inode_cachep, inode);
 112}
 113
 114static void fuse_destroy_inode(struct inode *inode)
 115{
 116        struct fuse_inode *fi = get_fuse_inode(inode);
 117        BUG_ON(!list_empty(&fi->write_files));
 118        BUG_ON(!list_empty(&fi->queued_writes));
 119        kfree(fi->forget);
 120        call_rcu(&inode->i_rcu, fuse_i_callback);
 121}
 122
 123static void fuse_evict_inode(struct inode *inode)
 124{
 125        truncate_inode_pages(&inode->i_data, 0);
 126        clear_inode(inode);
 127        if (inode->i_sb->s_flags & MS_ACTIVE) {
 128                struct fuse_conn *fc = get_fuse_conn(inode);
 129                struct fuse_inode *fi = get_fuse_inode(inode);
 130                fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
 131                fi->forget = NULL;
 132        }
 133}
 134
 135static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 136{
 137        if (*flags & MS_MANDLOCK)
 138                return -EINVAL;
 139
 140        return 0;
 141}
 142
 143/*
 144 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
 145 * so that it will fit.
 146 */
 147static ino_t fuse_squash_ino(u64 ino64)
 148{
 149        ino_t ino = (ino_t) ino64;
 150        if (sizeof(ino_t) < sizeof(u64))
 151                ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
 152        return ino;
 153}
 154
 155void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 156                                   u64 attr_valid)
 157{
 158        struct fuse_conn *fc = get_fuse_conn(inode);
 159        struct fuse_inode *fi = get_fuse_inode(inode);
 160
 161        fi->attr_version = ++fc->attr_version;
 162        fi->i_time = attr_valid;
 163
 164        inode->i_ino     = fuse_squash_ino(attr->ino);
 165        inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 166        set_nlink(inode, attr->nlink);
 167        inode->i_uid     = attr->uid;
 168        inode->i_gid     = attr->gid;
 169        inode->i_blocks  = attr->blocks;
 170        inode->i_atime.tv_sec   = attr->atime;
 171        inode->i_atime.tv_nsec  = attr->atimensec;
 172        inode->i_mtime.tv_sec   = attr->mtime;
 173        inode->i_mtime.tv_nsec  = attr->mtimensec;
 174        inode->i_ctime.tv_sec   = attr->ctime;
 175        inode->i_ctime.tv_nsec  = attr->ctimensec;
 176
 177        if (attr->blksize != 0)
 178                inode->i_blkbits = ilog2(attr->blksize);
 179        else
 180                inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 181
 182        /*
 183         * Don't set the sticky bit in i_mode, unless we want the VFS
 184         * to check permissions.  This prevents failures due to the
 185         * check in may_delete().
 186         */
 187        fi->orig_i_mode = inode->i_mode;
 188        if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
 189                inode->i_mode &= ~S_ISVTX;
 190
 191        fi->orig_ino = attr->ino;
 192}
 193
 194void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 195                            u64 attr_valid, u64 attr_version)
 196{
 197        struct fuse_conn *fc = get_fuse_conn(inode);
 198        struct fuse_inode *fi = get_fuse_inode(inode);
 199        loff_t oldsize;
 200        struct timespec old_mtime;
 201
 202        spin_lock(&fc->lock);
 203        if (attr_version != 0 && fi->attr_version > attr_version) {
 204                spin_unlock(&fc->lock);
 205                return;
 206        }
 207
 208        old_mtime = inode->i_mtime;
 209        fuse_change_attributes_common(inode, attr, attr_valid);
 210
 211        oldsize = inode->i_size;
 212        i_size_write(inode, attr->size);
 213        spin_unlock(&fc->lock);
 214
 215        if (S_ISREG(inode->i_mode)) {
 216                bool inval = false;
 217
 218                if (oldsize != attr->size) {
 219                        truncate_pagecache(inode, oldsize, attr->size);
 220                        inval = true;
 221                } else if (fc->auto_inval_data) {
 222                        struct timespec new_mtime = {
 223                                .tv_sec = attr->mtime,
 224                                .tv_nsec = attr->mtimensec,
 225                        };
 226
 227                        /*
 228                         * Auto inval mode also checks and invalidates if mtime
 229                         * has changed.
 230                         */
 231                        if (!timespec_equal(&old_mtime, &new_mtime))
 232                                inval = true;
 233                }
 234
 235                if (inval)
 236                        invalidate_inode_pages2(inode->i_mapping);
 237        }
 238}
 239
 240static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 241{
 242        inode->i_mode = attr->mode & S_IFMT;
 243        inode->i_size = attr->size;
 244        if (S_ISREG(inode->i_mode)) {
 245                fuse_init_common(inode);
 246                fuse_init_file_inode(inode);
 247        } else if (S_ISDIR(inode->i_mode))
 248                fuse_init_dir(inode);
 249        else if (S_ISLNK(inode->i_mode))
 250                fuse_init_symlink(inode);
 251        else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 252                 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 253                fuse_init_common(inode);
 254                init_special_inode(inode, inode->i_mode,
 255                                   new_decode_dev(attr->rdev));
 256        } else
 257                BUG();
 258}
 259
 260int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 261{
 262        u64 nodeid = *(u64 *) _nodeidp;
 263        if (get_node_id(inode) == nodeid)
 264                return 1;
 265        else
 266                return 0;
 267}
 268
 269static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 270{
 271        u64 nodeid = *(u64 *) _nodeidp;
 272        get_fuse_inode(inode)->nodeid = nodeid;
 273        return 0;
 274}
 275
 276struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 277                        int generation, struct fuse_attr *attr,
 278                        u64 attr_valid, u64 attr_version)
 279{
 280        struct inode *inode;
 281        struct fuse_inode *fi;
 282        struct fuse_conn *fc = get_fuse_conn_super(sb);
 283
 284 retry:
 285        inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 286        if (!inode)
 287                return NULL;
 288
 289        if ((inode->i_state & I_NEW)) {
 290                inode->i_flags |= S_NOATIME|S_NOCMTIME;
 291                inode->i_generation = generation;
 292                inode->i_data.backing_dev_info = &fc->bdi;
 293                fuse_init_inode(inode, attr);
 294                unlock_new_inode(inode);
 295        } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 296                /* Inode has changed type, any I/O on the old should fail */
 297                make_bad_inode(inode);
 298                iput(inode);
 299                goto retry;
 300        }
 301
 302        fi = get_fuse_inode(inode);
 303        spin_lock(&fc->lock);
 304        fi->nlookup++;
 305        spin_unlock(&fc->lock);
 306        fuse_change_attributes(inode, attr, attr_valid, attr_version);
 307
 308        return inode;
 309}
 310
 311int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 312                             loff_t offset, loff_t len)
 313{
 314        struct inode *inode;
 315        pgoff_t pg_start;
 316        pgoff_t pg_end;
 317
 318        inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
 319        if (!inode)
 320                return -ENOENT;
 321
 322        fuse_invalidate_attr(inode);
 323        if (offset >= 0) {
 324                pg_start = offset >> PAGE_CACHE_SHIFT;
 325                if (len <= 0)
 326                        pg_end = -1;
 327                else
 328                        pg_end = (offset + len - 1) >> PAGE_CACHE_SHIFT;
 329                invalidate_inode_pages2_range(inode->i_mapping,
 330                                              pg_start, pg_end);
 331        }
 332        iput(inode);
 333        return 0;
 334}
 335
 336static void fuse_umount_begin(struct super_block *sb)
 337{
 338        fuse_abort_conn(get_fuse_conn_super(sb));
 339}
 340
 341static void fuse_send_destroy(struct fuse_conn *fc)
 342{
 343        struct fuse_req *req = fc->destroy_req;
 344        if (req && fc->conn_init) {
 345                fc->destroy_req = NULL;
 346                req->in.h.opcode = FUSE_DESTROY;
 347                req->force = 1;
 348                fuse_request_send(fc, req);
 349                fuse_put_request(fc, req);
 350        }
 351}
 352
 353static void fuse_bdi_destroy(struct fuse_conn *fc)
 354{
 355        if (fc->bdi_initialized)
 356                bdi_destroy(&fc->bdi);
 357}
 358
 359void fuse_conn_kill(struct fuse_conn *fc)
 360{
 361        spin_lock(&fc->lock);
 362        fc->connected = 0;
 363        fc->blocked = 0;
 364        spin_unlock(&fc->lock);
 365        /* Flush all readers on this fs */
 366        kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 367        wake_up_all(&fc->waitq);
 368        wake_up_all(&fc->blocked_waitq);
 369        wake_up_all(&fc->reserved_req_waitq);
 370}
 371EXPORT_SYMBOL_GPL(fuse_conn_kill);
 372
 373static void fuse_put_super(struct super_block *sb)
 374{
 375        struct fuse_conn *fc = get_fuse_conn_super(sb);
 376
 377        fuse_send_destroy(fc);
 378
 379        fuse_conn_kill(fc);
 380        mutex_lock(&fuse_mutex);
 381        list_del(&fc->entry);
 382        fuse_ctl_remove_conn(fc);
 383        mutex_unlock(&fuse_mutex);
 384        fuse_bdi_destroy(fc);
 385
 386        fuse_conn_put(fc);
 387}
 388
 389static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 390{
 391        stbuf->f_type    = FUSE_SUPER_MAGIC;
 392        stbuf->f_bsize   = attr->bsize;
 393        stbuf->f_frsize  = attr->frsize;
 394        stbuf->f_blocks  = attr->blocks;
 395        stbuf->f_bfree   = attr->bfree;
 396        stbuf->f_bavail  = attr->bavail;
 397        stbuf->f_files   = attr->files;
 398        stbuf->f_ffree   = attr->ffree;
 399        stbuf->f_namelen = attr->namelen;
 400        /* fsid is left zero */
 401}
 402
 403static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 404{
 405        struct super_block *sb = dentry->d_sb;
 406        struct fuse_conn *fc = get_fuse_conn_super(sb);
 407        struct fuse_req *req;
 408        struct fuse_statfs_out outarg;
 409        int err;
 410
 411        if (!fuse_allow_task(fc, current)) {
 412                buf->f_type = FUSE_SUPER_MAGIC;
 413                return 0;
 414        }
 415
 416        req = fuse_get_req(fc);
 417        if (IS_ERR(req))
 418                return PTR_ERR(req);
 419
 420        memset(&outarg, 0, sizeof(outarg));
 421        req->in.numargs = 0;
 422        req->in.h.opcode = FUSE_STATFS;
 423        req->in.h.nodeid = get_node_id(dentry->d_inode);
 424        req->out.numargs = 1;
 425        req->out.args[0].size =
 426                fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 427        req->out.args[0].value = &outarg;
 428        fuse_request_send(fc, req);
 429        err = req->out.h.error;
 430        if (!err)
 431                convert_fuse_statfs(buf, &outarg.st);
 432        fuse_put_request(fc, req);
 433        return err;
 434}
 435
 436enum {
 437        OPT_FD,
 438        OPT_ROOTMODE,
 439        OPT_USER_ID,
 440        OPT_GROUP_ID,
 441        OPT_DEFAULT_PERMISSIONS,
 442        OPT_ALLOW_OTHER,
 443        OPT_MAX_READ,
 444        OPT_BLKSIZE,
 445        OPT_ERR
 446};
 447
 448static const match_table_t tokens = {
 449        {OPT_FD,                        "fd=%u"},
 450        {OPT_ROOTMODE,                  "rootmode=%o"},
 451        {OPT_USER_ID,                   "user_id=%u"},
 452        {OPT_GROUP_ID,                  "group_id=%u"},
 453        {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 454        {OPT_ALLOW_OTHER,               "allow_other"},
 455        {OPT_MAX_READ,                  "max_read=%u"},
 456        {OPT_BLKSIZE,                   "blksize=%u"},
 457        {OPT_ERR,                       NULL}
 458};
 459
 460static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 461{
 462        char *p;
 463        memset(d, 0, sizeof(struct fuse_mount_data));
 464        d->max_read = ~0;
 465        d->blksize = FUSE_DEFAULT_BLKSIZE;
 466
 467        while ((p = strsep(&opt, ",")) != NULL) {
 468                int token;
 469                int value;
 470                substring_t args[MAX_OPT_ARGS];
 471                if (!*p)
 472                        continue;
 473
 474                token = match_token(p, tokens, args);
 475                switch (token) {
 476                case OPT_FD:
 477                        if (match_int(&args[0], &value))
 478                                return 0;
 479                        d->fd = value;
 480                        d->fd_present = 1;
 481                        break;
 482
 483                case OPT_ROOTMODE:
 484                        if (match_octal(&args[0], &value))
 485                                return 0;
 486                        if (!fuse_valid_type(value))
 487                                return 0;
 488                        d->rootmode = value;
 489                        d->rootmode_present = 1;
 490                        break;
 491
 492                case OPT_USER_ID:
 493                        if (match_int(&args[0], &value))
 494                                return 0;
 495                        d->user_id = value;
 496                        d->user_id_present = 1;
 497                        break;
 498
 499                case OPT_GROUP_ID:
 500                        if (match_int(&args[0], &value))
 501                                return 0;
 502                        d->group_id = value;
 503                        d->group_id_present = 1;
 504                        break;
 505
 506                case OPT_DEFAULT_PERMISSIONS:
 507                        d->flags |= FUSE_DEFAULT_PERMISSIONS;
 508                        break;
 509
 510                case OPT_ALLOW_OTHER:
 511                        d->flags |= FUSE_ALLOW_OTHER;
 512                        break;
 513
 514                case OPT_MAX_READ:
 515                        if (match_int(&args[0], &value))
 516                                return 0;
 517                        d->max_read = value;
 518                        break;
 519
 520                case OPT_BLKSIZE:
 521                        if (!is_bdev || match_int(&args[0], &value))
 522                                return 0;
 523                        d->blksize = value;
 524                        break;
 525
 526                default:
 527                        return 0;
 528                }
 529        }
 530
 531        if (!d->fd_present || !d->rootmode_present ||
 532            !d->user_id_present || !d->group_id_present)
 533                return 0;
 534
 535        return 1;
 536}
 537
 538static int fuse_show_options(struct seq_file *m, struct dentry *root)
 539{
 540        struct super_block *sb = root->d_sb;
 541        struct fuse_conn *fc = get_fuse_conn_super(sb);
 542
 543        seq_printf(m, ",user_id=%u", fc->user_id);
 544        seq_printf(m, ",group_id=%u", fc->group_id);
 545        if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 546                seq_puts(m, ",default_permissions");
 547        if (fc->flags & FUSE_ALLOW_OTHER)
 548                seq_puts(m, ",allow_other");
 549        if (fc->max_read != ~0)
 550                seq_printf(m, ",max_read=%u", fc->max_read);
 551        if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 552                seq_printf(m, ",blksize=%lu", sb->s_blocksize);
 553        return 0;
 554}
 555
 556void fuse_conn_init(struct fuse_conn *fc)
 557{
 558        memset(fc, 0, sizeof(*fc));
 559        spin_lock_init(&fc->lock);
 560        mutex_init(&fc->inst_mutex);
 561        init_rwsem(&fc->killsb);
 562        atomic_set(&fc->count, 1);
 563        init_waitqueue_head(&fc->waitq);
 564        init_waitqueue_head(&fc->blocked_waitq);
 565        init_waitqueue_head(&fc->reserved_req_waitq);
 566        INIT_LIST_HEAD(&fc->pending);
 567        INIT_LIST_HEAD(&fc->processing);
 568        INIT_LIST_HEAD(&fc->io);
 569        INIT_LIST_HEAD(&fc->interrupts);
 570        INIT_LIST_HEAD(&fc->bg_queue);
 571        INIT_LIST_HEAD(&fc->entry);
 572        fc->forget_list_tail = &fc->forget_list_head;
 573        atomic_set(&fc->num_waiting, 0);
 574        fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
 575        fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
 576        fc->khctr = 0;
 577        fc->polled_files = RB_ROOT;
 578        fc->reqctr = 0;
 579        fc->blocked = 1;
 580        fc->attr_version = 1;
 581        get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 582}
 583EXPORT_SYMBOL_GPL(fuse_conn_init);
 584
 585void fuse_conn_put(struct fuse_conn *fc)
 586{
 587        if (atomic_dec_and_test(&fc->count)) {
 588                if (fc->destroy_req)
 589                        fuse_request_free(fc->destroy_req);
 590                mutex_destroy(&fc->inst_mutex);
 591                fc->release(fc);
 592        }
 593}
 594EXPORT_SYMBOL_GPL(fuse_conn_put);
 595
 596struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 597{
 598        atomic_inc(&fc->count);
 599        return fc;
 600}
 601EXPORT_SYMBOL_GPL(fuse_conn_get);
 602
 603static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 604{
 605        struct fuse_attr attr;
 606        memset(&attr, 0, sizeof(attr));
 607
 608        attr.mode = mode;
 609        attr.ino = FUSE_ROOT_ID;
 610        attr.nlink = 1;
 611        return fuse_iget(sb, 1, 0, &attr, 0, 0);
 612}
 613
 614struct fuse_inode_handle {
 615        u64 nodeid;
 616        u32 generation;
 617};
 618
 619static struct dentry *fuse_get_dentry(struct super_block *sb,
 620                                      struct fuse_inode_handle *handle)
 621{
 622        struct fuse_conn *fc = get_fuse_conn_super(sb);
 623        struct inode *inode;
 624        struct dentry *entry;
 625        int err = -ESTALE;
 626
 627        if (handle->nodeid == 0)
 628                goto out_err;
 629
 630        inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 631        if (!inode) {
 632                struct fuse_entry_out outarg;
 633                struct qstr name;
 634
 635                if (!fc->export_support)
 636                        goto out_err;
 637
 638                name.len = 1;
 639                name.name = ".";
 640                err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 641                                       &inode);
 642                if (err && err != -ENOENT)
 643                        goto out_err;
 644                if (err || !inode) {
 645                        err = -ESTALE;
 646                        goto out_err;
 647                }
 648                err = -EIO;
 649                if (get_node_id(inode) != handle->nodeid)
 650                        goto out_iput;
 651        }
 652        err = -ESTALE;
 653        if (inode->i_generation != handle->generation)
 654                goto out_iput;
 655
 656        entry = d_obtain_alias(inode);
 657        if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
 658                fuse_invalidate_entry_cache(entry);
 659
 660        return entry;
 661
 662 out_iput:
 663        iput(inode);
 664 out_err:
 665        return ERR_PTR(err);
 666}
 667
 668static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
 669                           struct inode *parent)
 670{
 671        int len = parent ? 6 : 3;
 672        u64 nodeid;
 673        u32 generation;
 674
 675        if (*max_len < len) {
 676                *max_len = len;
 677                return  255;
 678        }
 679
 680        nodeid = get_fuse_inode(inode)->nodeid;
 681        generation = inode->i_generation;
 682
 683        fh[0] = (u32)(nodeid >> 32);
 684        fh[1] = (u32)(nodeid & 0xffffffff);
 685        fh[2] = generation;
 686
 687        if (parent) {
 688                nodeid = get_fuse_inode(parent)->nodeid;
 689                generation = parent->i_generation;
 690
 691                fh[3] = (u32)(nodeid >> 32);
 692                fh[4] = (u32)(nodeid & 0xffffffff);
 693                fh[5] = generation;
 694        }
 695
 696        *max_len = len;
 697        return parent ? 0x82 : 0x81;
 698}
 699
 700static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 701                struct fid *fid, int fh_len, int fh_type)
 702{
 703        struct fuse_inode_handle handle;
 704
 705        if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 706                return NULL;
 707
 708        handle.nodeid = (u64) fid->raw[0] << 32;
 709        handle.nodeid |= (u64) fid->raw[1];
 710        handle.generation = fid->raw[2];
 711        return fuse_get_dentry(sb, &handle);
 712}
 713
 714static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 715                struct fid *fid, int fh_len, int fh_type)
 716{
 717        struct fuse_inode_handle parent;
 718
 719        if (fh_type != 0x82 || fh_len < 6)
 720                return NULL;
 721
 722        parent.nodeid = (u64) fid->raw[3] << 32;
 723        parent.nodeid |= (u64) fid->raw[4];
 724        parent.generation = fid->raw[5];
 725        return fuse_get_dentry(sb, &parent);
 726}
 727
 728static struct dentry *fuse_get_parent(struct dentry *child)
 729{
 730        struct inode *child_inode = child->d_inode;
 731        struct fuse_conn *fc = get_fuse_conn(child_inode);
 732        struct inode *inode;
 733        struct dentry *parent;
 734        struct fuse_entry_out outarg;
 735        struct qstr name;
 736        int err;
 737
 738        if (!fc->export_support)
 739                return ERR_PTR(-ESTALE);
 740
 741        name.len = 2;
 742        name.name = "..";
 743        err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 744                               &name, &outarg, &inode);
 745        if (err) {
 746                if (err == -ENOENT)
 747                        return ERR_PTR(-ESTALE);
 748                return ERR_PTR(err);
 749        }
 750
 751        parent = d_obtain_alias(inode);
 752        if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
 753                fuse_invalidate_entry_cache(parent);
 754
 755        return parent;
 756}
 757
 758static const struct export_operations fuse_export_operations = {
 759        .fh_to_dentry   = fuse_fh_to_dentry,
 760        .fh_to_parent   = fuse_fh_to_parent,
 761        .encode_fh      = fuse_encode_fh,
 762        .get_parent     = fuse_get_parent,
 763};
 764
 765static const struct super_operations fuse_super_operations = {
 766        .alloc_inode    = fuse_alloc_inode,
 767        .destroy_inode  = fuse_destroy_inode,
 768        .evict_inode    = fuse_evict_inode,
 769        .drop_inode     = generic_delete_inode,
 770        .remount_fs     = fuse_remount_fs,
 771        .put_super      = fuse_put_super,
 772        .umount_begin   = fuse_umount_begin,
 773        .statfs         = fuse_statfs,
 774        .show_options   = fuse_show_options,
 775};
 776
 777static void sanitize_global_limit(unsigned *limit)
 778{
 779        if (*limit == 0)
 780                *limit = ((num_physpages << PAGE_SHIFT) >> 13) /
 781                         sizeof(struct fuse_req);
 782
 783        if (*limit >= 1 << 16)
 784                *limit = (1 << 16) - 1;
 785}
 786
 787static int set_global_limit(const char *val, struct kernel_param *kp)
 788{
 789        int rv;
 790
 791        rv = param_set_uint(val, kp);
 792        if (rv)
 793                return rv;
 794
 795        sanitize_global_limit((unsigned *)kp->arg);
 796
 797        return 0;
 798}
 799
 800static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
 801{
 802        int cap_sys_admin = capable(CAP_SYS_ADMIN);
 803
 804        if (arg->minor < 13)
 805                return;
 806
 807        sanitize_global_limit(&max_user_bgreq);
 808        sanitize_global_limit(&max_user_congthresh);
 809
 810        if (arg->max_background) {
 811                fc->max_background = arg->max_background;
 812
 813                if (!cap_sys_admin && fc->max_background > max_user_bgreq)
 814                        fc->max_background = max_user_bgreq;
 815        }
 816        if (arg->congestion_threshold) {
 817                fc->congestion_threshold = arg->congestion_threshold;
 818
 819                if (!cap_sys_admin &&
 820                    fc->congestion_threshold > max_user_congthresh)
 821                        fc->congestion_threshold = max_user_congthresh;
 822        }
 823}
 824
 825static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 826{
 827        struct fuse_init_out *arg = &req->misc.init_out;
 828
 829        if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 830                fc->conn_error = 1;
 831        else {
 832                unsigned long ra_pages;
 833
 834                process_init_limits(fc, arg);
 835
 836                if (arg->minor >= 6) {
 837                        ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 838                        if (arg->flags & FUSE_ASYNC_READ)
 839                                fc->async_read = 1;
 840                        if (!(arg->flags & FUSE_POSIX_LOCKS))
 841                                fc->no_lock = 1;
 842                        if (arg->minor >= 17) {
 843                                if (!(arg->flags & FUSE_FLOCK_LOCKS))
 844                                        fc->no_flock = 1;
 845                        } else {
 846                                if (!(arg->flags & FUSE_POSIX_LOCKS))
 847                                        fc->no_flock = 1;
 848                        }
 849                        if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 850                                fc->atomic_o_trunc = 1;
 851                        if (arg->minor >= 9) {
 852                                /* LOOKUP has dependency on proto version */
 853                                if (arg->flags & FUSE_EXPORT_SUPPORT)
 854                                        fc->export_support = 1;
 855                        }
 856                        if (arg->flags & FUSE_BIG_WRITES)
 857                                fc->big_writes = 1;
 858                        if (arg->flags & FUSE_DONT_MASK)
 859                                fc->dont_mask = 1;
 860                        if (arg->flags & FUSE_AUTO_INVAL_DATA)
 861                                fc->auto_inval_data = 1;
 862                } else {
 863                        ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 864                        fc->no_lock = 1;
 865                        fc->no_flock = 1;
 866                }
 867
 868                fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 869                fc->minor = arg->minor;
 870                fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 871                fc->max_write = max_t(unsigned, 4096, fc->max_write);
 872                fc->conn_init = 1;
 873        }
 874        fc->blocked = 0;
 875        wake_up_all(&fc->blocked_waitq);
 876}
 877
 878static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 879{
 880        struct fuse_init_in *arg = &req->misc.init_in;
 881
 882        arg->major = FUSE_KERNEL_VERSION;
 883        arg->minor = FUSE_KERNEL_MINOR_VERSION;
 884        arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 885        arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 886                FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 887                FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
 888                FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA;
 889        req->in.h.opcode = FUSE_INIT;
 890        req->in.numargs = 1;
 891        req->in.args[0].size = sizeof(*arg);
 892        req->in.args[0].value = arg;
 893        req->out.numargs = 1;
 894        /* Variable length argument used for backward compatibility
 895           with interface version < 7.5.  Rest of init_out is zeroed
 896           by do_get_request(), so a short reply is not a problem */
 897        req->out.argvar = 1;
 898        req->out.args[0].size = sizeof(struct fuse_init_out);
 899        req->out.args[0].value = &req->misc.init_out;
 900        req->end = process_init_reply;
 901        fuse_request_send_background(fc, req);
 902}
 903
 904static void fuse_free_conn(struct fuse_conn *fc)
 905{
 906        kfree(fc);
 907}
 908
 909static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 910{
 911        int err;
 912
 913        fc->bdi.name = "fuse";
 914        fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 915        /* fuse does it's own writeback accounting */
 916        fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
 917
 918        err = bdi_init(&fc->bdi);
 919        if (err)
 920                return err;
 921
 922        fc->bdi_initialized = 1;
 923
 924        if (sb->s_bdev) {
 925                err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
 926                                    MAJOR(fc->dev), MINOR(fc->dev));
 927        } else {
 928                err = bdi_register_dev(&fc->bdi, fc->dev);
 929        }
 930
 931        if (err)
 932                return err;
 933
 934        /*
 935         * For a single fuse filesystem use max 1% of dirty +
 936         * writeback threshold.
 937         *
 938         * This gives about 1M of write buffer for memory maps on a
 939         * machine with 1G and 10% dirty_ratio, which should be more
 940         * than enough.
 941         *
 942         * Privileged users can raise it by writing to
 943         *
 944         *    /sys/class/bdi/<bdi>/max_ratio
 945         */
 946        bdi_set_max_ratio(&fc->bdi, 1);
 947
 948        return 0;
 949}
 950
 951static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 952{
 953        struct fuse_conn *fc;
 954        struct inode *root;
 955        struct fuse_mount_data d;
 956        struct file *file;
 957        struct dentry *root_dentry;
 958        struct fuse_req *init_req;
 959        int err;
 960        int is_bdev = sb->s_bdev != NULL;
 961
 962        err = -EINVAL;
 963        if (sb->s_flags & MS_MANDLOCK)
 964                goto err;
 965
 966        sb->s_flags &= ~MS_NOSEC;
 967
 968        if (!parse_fuse_opt((char *) data, &d, is_bdev))
 969                goto err;
 970
 971        if (is_bdev) {
 972#ifdef CONFIG_BLOCK
 973                err = -EINVAL;
 974                if (!sb_set_blocksize(sb, d.blksize))
 975                        goto err;
 976#endif
 977        } else {
 978                sb->s_blocksize = PAGE_CACHE_SIZE;
 979                sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 980        }
 981        sb->s_magic = FUSE_SUPER_MAGIC;
 982        sb->s_op = &fuse_super_operations;
 983        sb->s_maxbytes = MAX_LFS_FILESIZE;
 984        sb->s_time_gran = 1;
 985        sb->s_export_op = &fuse_export_operations;
 986
 987        file = fget(d.fd);
 988        err = -EINVAL;
 989        if (!file)
 990                goto err;
 991
 992        if (file->f_op != &fuse_dev_operations)
 993                goto err_fput;
 994
 995        fc = kmalloc(sizeof(*fc), GFP_KERNEL);
 996        err = -ENOMEM;
 997        if (!fc)
 998                goto err_fput;
 999
1000        fuse_conn_init(fc);
1001
1002        fc->dev = sb->s_dev;
1003        fc->sb = sb;
1004        err = fuse_bdi_init(fc, sb);
1005        if (err)
1006                goto err_put_conn;
1007
1008        sb->s_bdi = &fc->bdi;
1009
1010        /* Handle umasking inside the fuse code */
1011        if (sb->s_flags & MS_POSIXACL)
1012                fc->dont_mask = 1;
1013        sb->s_flags |= MS_POSIXACL;
1014
1015        fc->release = fuse_free_conn;
1016        fc->flags = d.flags;
1017        fc->user_id = d.user_id;
1018        fc->group_id = d.group_id;
1019        fc->max_read = max_t(unsigned, 4096, d.max_read);
1020
1021        /* Used by get_root_inode() */
1022        sb->s_fs_info = fc;
1023
1024        err = -ENOMEM;
1025        root = fuse_get_root_inode(sb, d.rootmode);
1026        root_dentry = d_make_root(root);
1027        if (!root_dentry)
1028                goto err_put_conn;
1029        /* only now - we want root dentry with NULL ->d_op */
1030        sb->s_d_op = &fuse_dentry_operations;
1031
1032        init_req = fuse_request_alloc();
1033        if (!init_req)
1034                goto err_put_root;
1035
1036        if (is_bdev) {
1037                fc->destroy_req = fuse_request_alloc();
1038                if (!fc->destroy_req)
1039                        goto err_free_init_req;
1040        }
1041
1042        mutex_lock(&fuse_mutex);
1043        err = -EINVAL;
1044        if (file->private_data)
1045                goto err_unlock;
1046
1047        err = fuse_ctl_add_conn(fc);
1048        if (err)
1049                goto err_unlock;
1050
1051        list_add_tail(&fc->entry, &fuse_conn_list);
1052        sb->s_root = root_dentry;
1053        fc->connected = 1;
1054        file->private_data = fuse_conn_get(fc);
1055        mutex_unlock(&fuse_mutex);
1056        /*
1057         * atomic_dec_and_test() in fput() provides the necessary
1058         * memory barrier for file->private_data to be visible on all
1059         * CPUs after this
1060         */
1061        fput(file);
1062
1063        fuse_send_init(fc, init_req);
1064
1065        return 0;
1066
1067 err_unlock:
1068        mutex_unlock(&fuse_mutex);
1069 err_free_init_req:
1070        fuse_request_free(init_req);
1071 err_put_root:
1072        dput(root_dentry);
1073 err_put_conn:
1074        fuse_bdi_destroy(fc);
1075        fuse_conn_put(fc);
1076 err_fput:
1077        fput(file);
1078 err:
1079        return err;
1080}
1081
1082static struct dentry *fuse_mount(struct file_system_type *fs_type,
1083                       int flags, const char *dev_name,
1084                       void *raw_data)
1085{
1086        return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1087}
1088
1089static void fuse_kill_sb_anon(struct super_block *sb)
1090{
1091        struct fuse_conn *fc = get_fuse_conn_super(sb);
1092
1093        if (fc) {
1094                down_write(&fc->killsb);
1095                fc->sb = NULL;
1096                up_write(&fc->killsb);
1097        }
1098
1099        kill_anon_super(sb);
1100}
1101
1102static struct file_system_type fuse_fs_type = {
1103        .owner          = THIS_MODULE,
1104        .name           = "fuse",
1105        .fs_flags       = FS_HAS_SUBTYPE,
1106        .mount          = fuse_mount,
1107        .kill_sb        = fuse_kill_sb_anon,
1108};
1109
1110#ifdef CONFIG_BLOCK
1111static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1112                           int flags, const char *dev_name,
1113                           void *raw_data)
1114{
1115        return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1116}
1117
1118static void fuse_kill_sb_blk(struct super_block *sb)
1119{
1120        struct fuse_conn *fc = get_fuse_conn_super(sb);
1121
1122        if (fc) {
1123                down_write(&fc->killsb);
1124                fc->sb = NULL;
1125                up_write(&fc->killsb);
1126        }
1127
1128        kill_block_super(sb);
1129}
1130
1131static struct file_system_type fuseblk_fs_type = {
1132        .owner          = THIS_MODULE,
1133        .name           = "fuseblk",
1134        .mount          = fuse_mount_blk,
1135        .kill_sb        = fuse_kill_sb_blk,
1136        .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1137};
1138
1139static inline int register_fuseblk(void)
1140{
1141        return register_filesystem(&fuseblk_fs_type);
1142}
1143
1144static inline void unregister_fuseblk(void)
1145{
1146        unregister_filesystem(&fuseblk_fs_type);
1147}
1148#else
1149static inline int register_fuseblk(void)
1150{
1151        return 0;
1152}
1153
1154static inline void unregister_fuseblk(void)
1155{
1156}
1157#endif
1158
1159static void fuse_inode_init_once(void *foo)
1160{
1161        struct inode *inode = foo;
1162
1163        inode_init_once(inode);
1164}
1165
1166static int __init fuse_fs_init(void)
1167{
1168        int err;
1169
1170        fuse_inode_cachep = kmem_cache_create("fuse_inode",
1171                                              sizeof(struct fuse_inode),
1172                                              0, SLAB_HWCACHE_ALIGN,
1173                                              fuse_inode_init_once);
1174        err = -ENOMEM;
1175        if (!fuse_inode_cachep)
1176                goto out;
1177
1178        err = register_fuseblk();
1179        if (err)
1180                goto out2;
1181
1182        err = register_filesystem(&fuse_fs_type);
1183        if (err)
1184                goto out3;
1185
1186        return 0;
1187
1188 out3:
1189        unregister_fuseblk();
1190 out2:
1191        kmem_cache_destroy(fuse_inode_cachep);
1192 out:
1193        return err;
1194}
1195
1196static void fuse_fs_cleanup(void)
1197{
1198        unregister_filesystem(&fuse_fs_type);
1199        unregister_fuseblk();
1200
1201        /*
1202         * Make sure all delayed rcu free inodes are flushed before we
1203         * destroy cache.
1204         */
1205        rcu_barrier();
1206        kmem_cache_destroy(fuse_inode_cachep);
1207}
1208
1209static struct kobject *fuse_kobj;
1210static struct kobject *connections_kobj;
1211
1212static int fuse_sysfs_init(void)
1213{
1214        int err;
1215
1216        fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1217        if (!fuse_kobj) {
1218                err = -ENOMEM;
1219                goto out_err;
1220        }
1221
1222        connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1223        if (!connections_kobj) {
1224                err = -ENOMEM;
1225                goto out_fuse_unregister;
1226        }
1227
1228        return 0;
1229
1230 out_fuse_unregister:
1231        kobject_put(fuse_kobj);
1232 out_err:
1233        return err;
1234}
1235
1236static void fuse_sysfs_cleanup(void)
1237{
1238        kobject_put(connections_kobj);
1239        kobject_put(fuse_kobj);
1240}
1241
1242static int __init fuse_init(void)
1243{
1244        int res;
1245
1246        printk(KERN_INFO "fuse init (API version %i.%i)\n",
1247               FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1248
1249        INIT_LIST_HEAD(&fuse_conn_list);
1250        res = fuse_fs_init();
1251        if (res)
1252                goto err;
1253
1254        res = fuse_dev_init();
1255        if (res)
1256                goto err_fs_cleanup;
1257
1258        res = fuse_sysfs_init();
1259        if (res)
1260                goto err_dev_cleanup;
1261
1262        res = fuse_ctl_init();
1263        if (res)
1264                goto err_sysfs_cleanup;
1265
1266        sanitize_global_limit(&max_user_bgreq);
1267        sanitize_global_limit(&max_user_congthresh);
1268
1269        return 0;
1270
1271 err_sysfs_cleanup:
1272        fuse_sysfs_cleanup();
1273 err_dev_cleanup:
1274        fuse_dev_cleanup();
1275 err_fs_cleanup:
1276        fuse_fs_cleanup();
1277 err:
1278        return res;
1279}
1280
1281static void __exit fuse_exit(void)
1282{
1283        printk(KERN_DEBUG "fuse exit\n");
1284
1285        fuse_ctl_cleanup();
1286        fuse_sysfs_cleanup();
1287        fuse_fs_cleanup();
1288        fuse_dev_cleanup();
1289}
1290
1291module_init(fuse_init);
1292module_exit(fuse_exit);
1293
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