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