fs/fuse/fuse_i.h

   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 #ifndef _FS_FUSE_I_H
  10 #define _FS_FUSE_I_H
  11
  12 #include <linux/fuse.h>
  13 #include <linux/fs.h>
  14 #include <linux/mount.h>
  15 #include <linux/wait.h>
  16 #include <linux/list.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/mm.h>
  19 #include <linux/backing-dev.h>
  20 #include <linux/mutex.h>
  21 #include <linux/rwsem.h>
  22 #include <linux/rbtree.h>
  23 #include <linux/poll.h>
  24
  25 /** Max number of pages that can be used in a single read request */
  26 #define FUSE_MAX_PAGES_PER_REQ 32
  27
  28 /** Bias for fi->writectr, meaning new writepages must not be sent */
  29 #define FUSE_NOWRITE INT_MIN
  30
  31 /** It could be as large as PATH_MAX, but would that have any uses? */
  32 #define FUSE_NAME_MAX 1024
  33
  34 /** Number of dentries for each connection in the control filesystem */
  35 #define FUSE_CTL_NUM_DENTRIES 5
  36
  37 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
  38     module will check permissions based on the file mode.  Otherwise no
  39     permission checking is done in the kernel */
  40 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
  41
  42 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
  43     doing the mount will be allowed to access the filesystem */
  44 #define FUSE_ALLOW_OTHER         (1 << 1)
  45
  46 /** List of active connections */
  47 extern struct list_head fuse_conn_list;
  48
  49 /** Global mutex protecting fuse_conn_list and the control filesystem */
  50 extern struct mutex fuse_mutex;
  51
  52 /** Module parameters */
  53 extern unsigned max_user_bgreq;
  54 extern unsigned max_user_congthresh;
  55
  56 /** FUSE inode */
  57 struct fuse_inode {
  58         /** Inode data */
  59         struct inode inode;
  60
  61         /** Unique ID, which identifies the inode between userspace
  62          * and kernel */
  63         u64 nodeid;
  64
  65         /** Number of lookups on this inode */
  66         u64 nlookup;
  67
  68         /** The request used for sending the FORGET message */
  69         struct fuse_req *forget_req;
  70
  71         /** Time in jiffies until the file attributes are valid */
  72         u64 i_time;
  73
  74         /** The sticky bit in inode->i_mode may have been removed, so
  75             preserve the original mode */
  76         mode_t orig_i_mode;
  77
  78         /** Version of last attribute change */
  79         u64 attr_version;
  80
  81         /** Files usable in writepage.  Protected by fc->lock */
  82         struct list_head write_files;
  83
  84         /** Writepages pending on truncate or fsync */
  85         struct list_head queued_writes;
  86
  87         /** Number of sent writes, a negative bias (FUSE_NOWRITE)
  88          * means more writes are blocked */
  89         int writectr;
  90
  91         /** Waitq for writepage completion */
  92         wait_queue_head_t page_waitq;
  93
  94         /** List of writepage requestst (pending or sent) */
  95         struct list_head writepages;
  96 };
  97
  98 struct fuse_conn;
  99
 100 /** FUSE specific file data */
 101 struct fuse_file {
 102         /** Fuse connection for this file */
 103         struct fuse_conn *fc;
 104
 105         /** Request reserved for flush and release */
 106         struct fuse_req *reserved_req;
 107
 108         /** Kernel file handle guaranteed to be unique */
 109         u64 kh;
 110
 111         /** File handle used by userspace */
 112         u64 fh;
 113
 114         /** Node id of this file */
 115         u64 nodeid;
 116
 117         /** Refcount */
 118         atomic_t count;
 119
 120         /** FOPEN_* flags returned by open */
 121         u32 open_flags;
 122
 123         /** Entry on inode's write_files list */
 124         struct list_head write_entry;
 125
 126         /** RB node to be linked on fuse_conn->polled_files */
 127         struct rb_node polled_node;
 128
 129         /** Wait queue head for poll */
 130         wait_queue_head_t poll_wait;
 131 };
 132
 133 /** One input argument of a request */
 134 struct fuse_in_arg {
 135         unsigned size;
 136         const void *value;
 137 };
 138
 139 /** The request input */
 140 struct fuse_in {
 141         /** The request header */
 142         struct fuse_in_header h;
 143
 144         /** True if the data for the last argument is in req->pages */
 145         unsigned argpages:1;
 146
 147         /** Number of arguments */
 148         unsigned numargs;
 149
 150         /** Array of arguments */
 151         struct fuse_in_arg args[3];
 152 };
 153
 154 /** One output argument of a request */
 155 struct fuse_arg {
 156         unsigned size;
 157         void *value;
 158 };
 159
 160 /** The request output */
 161 struct fuse_out {
 162         /** Header returned from userspace */
 163         struct fuse_out_header h;
 164
 165         /*
 166          * The following bitfields are not changed during the request
 167          * processing
 168          */
 169
 170         /** Last argument is variable length (can be shorter than
 171             arg->size) */
 172         unsigned argvar:1;
 173
 174         /** Last argument is a list of pages to copy data to */
 175         unsigned argpages:1;
 176
 177         /** Zero partially or not copied pages */
 178         unsigned page_zeroing:1;
 179
 180         /** Number or arguments */
 181         unsigned numargs;
 182
 183         /** Array of arguments */
 184         struct fuse_arg args[3];
 185 };
 186
 187 /** The request state */
 188 enum fuse_req_state {
 189         FUSE_REQ_INIT = 0,
 190         FUSE_REQ_PENDING,
 191         FUSE_REQ_READING,
 192         FUSE_REQ_SENT,
 193         FUSE_REQ_WRITING,
 194         FUSE_REQ_FINISHED
 195 };
 196
 197 /**
 198  * A request to the client
 199  */
 200 struct fuse_req {
 201         /** This can be on either pending processing or io lists in
 202             fuse_conn */
 203         struct list_head list;
 204
 205         /** Entry on the interrupts list  */
 206         struct list_head intr_entry;
 207
 208         /** refcount */
 209         atomic_t count;
 210
 211         /** Unique ID for the interrupt request */
 212         u64 intr_unique;
 213
 214         /*
 215          * The following bitfields are either set once before the
 216          * request is queued or setting/clearing them is protected by
 217          * fuse_conn->lock
 218          */
 219
 220         /** True if the request has reply */
 221         unsigned isreply:1;
 222
 223         /** Force sending of the request even if interrupted */
 224         unsigned force:1;
 225
 226         /** The request was aborted */
 227         unsigned aborted:1;
 228
 229         /** Request is sent in the background */
 230         unsigned background:1;
 231
 232         /** The request has been interrupted */
 233         unsigned interrupted:1;
 234
 235         /** Data is being copied to/from the request */
 236         unsigned locked:1;
 237
 238         /** Request is counted as "waiting" */
 239         unsigned waiting:1;
 240
 241         /** State of the request */
 242         enum fuse_req_state state;
 243
 244         /** The request input */
 245         struct fuse_in in;
 246
 247         /** The request output */
 248         struct fuse_out out;
 249
 250         /** Used to wake up the task waiting for completion of request*/
 251         wait_queue_head_t waitq;
 252
 253         /** Data for asynchronous requests */
 254         union {
 255                 struct fuse_forget_in forget_in;
 256                 struct {
 257                         struct fuse_release_in in;
 258                         struct path path;
 259                 } release;
 260                 struct fuse_init_in init_in;
 261                 struct fuse_init_out init_out;
 262                 struct cuse_init_in cuse_init_in;
 263                 struct cuse_init_out cuse_init_out;
 264                 struct {
 265                         struct fuse_read_in in;
 266                         u64 attr_ver;
 267                 } read;
 268                 struct {
 269                         struct fuse_write_in in;
 270                         struct fuse_write_out out;
 271                 } write;
 272                 struct fuse_lk_in lk_in;
 273         } misc;
 274
 275         /** page vector */
 276         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 277
 278         /** number of pages in vector */
 279         unsigned num_pages;
 280
 281         /** offset of data on first page */
 282         unsigned page_offset;
 283
 284         /** File used in the request (or NULL) */
 285         struct fuse_file *ff;
 286
 287         /** Inode used in the request or NULL */
 288         struct inode *inode;
 289
 290         /** Link on fi->writepages */
 291         struct list_head writepages_entry;
 292
 293         /** Request completion callback */
 294         void (*end)(struct fuse_conn *, struct fuse_req *);
 295
 296         /** Request is stolen from fuse_file->reserved_req */
 297         struct file *stolen_file;
 298 };
 299
 300 /**
 301  * A Fuse connection.
 302  *
 303  * This structure is created, when the filesystem is mounted, and is
 304  * destroyed, when the client device is closed and the filesystem is
 305  * unmounted.
 306  */
 307 struct fuse_conn {
 308         /** Lock protecting accessess to  members of this structure */
 309         spinlock_t lock;
 310
 311         /** Mutex protecting against directory alias creation */
 312         struct mutex inst_mutex;
 313
 314         /** Refcount */
 315         atomic_t count;
 316
 317         /** The user id for this mount */
 318         uid_t user_id;
 319
 320         /** The group id for this mount */
 321         gid_t group_id;
 322
 323         /** The fuse mount flags for this mount */
 324         unsigned flags;
 325
 326         /** Maximum read size */
 327         unsigned max_read;
 328
 329         /** Maximum write size */
 330         unsigned max_write;
 331
 332         /** Readers of the connection are waiting on this */
 333         wait_queue_head_t waitq;
 334
 335         /** The list of pending requests */
 336         struct list_head pending;
 337
 338         /** The list of requests being processed */
 339         struct list_head processing;
 340
 341         /** The list of requests under I/O */
 342         struct list_head io;
 343
 344         /** The next unique kernel file handle */
 345         u64 khctr;
 346
 347         /** rbtree of fuse_files waiting for poll events indexed by ph */
 348         struct rb_root polled_files;
 349
 350         /** Maximum number of outstanding background requests */
 351         unsigned max_background;
 352
 353         /** Number of background requests at which congestion starts */
 354         unsigned congestion_threshold;
 355
 356         /** Number of requests currently in the background */
 357         unsigned num_background;
 358
 359         /** Number of background requests currently queued for userspace */
 360         unsigned active_background;
 361
 362         /** The list of background requests set aside for later queuing */
 363         struct list_head bg_queue;
 364
 365         /** Pending interrupts */
 366         struct list_head interrupts;
 367
 368         /** Flag indicating if connection is blocked.  This will be
 369             the case before the INIT reply is received, and if there
 370             are too many outstading backgrounds requests */
 371         int blocked;
 372
 373         /** waitq for blocked connection */
 374         wait_queue_head_t blocked_waitq;
 375
 376         /** waitq for reserved requests */
 377         wait_queue_head_t reserved_req_waitq;
 378
 379         /** The next unique request id */
 380         u64 reqctr;
 381
 382         /** Connection established, cleared on umount, connection
 383             abort and device release */
 384         unsigned connected;
 385
 386         /** Connection failed (version mismatch).  Cannot race with
 387             setting other bitfields since it is only set once in INIT
 388             reply, before any other request, and never cleared */
 389         unsigned conn_error:1;
 390
 391         /** Connection successful.  Only set in INIT */
 392         unsigned conn_init:1;
 393
 394         /** Do readpages asynchronously?  Only set in INIT */
 395         unsigned async_read:1;
 396
 397         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 398         unsigned atomic_o_trunc:1;
 399
 400         /** Filesystem supports NFS exporting.  Only set in INIT */
 401         unsigned export_support:1;
 402
 403         /** Set if bdi is valid */
 404         unsigned bdi_initialized:1;
 405
 406         /*
 407          * The following bitfields are only for optimization purposes
 408          * and hence races in setting them will not cause malfunction
 409          */
 410
 411         /** Is fsync not implemented by fs? */
 412         unsigned no_fsync:1;
 413
 414         /** Is fsyncdir not implemented by fs? */
 415         unsigned no_fsyncdir:1;
 416
 417         /** Is flush not implemented by fs? */
 418         unsigned no_flush:1;
 419
 420         /** Is setxattr not implemented by fs? */
 421         unsigned no_setxattr:1;
 422
 423         /** Is getxattr not implemented by fs? */
 424         unsigned no_getxattr:1;
 425
 426         /** Is listxattr not implemented by fs? */
 427         unsigned no_listxattr:1;
 428
 429         /** Is removexattr not implemented by fs? */
 430         unsigned no_removexattr:1;
 431
 432         /** Are file locking primitives not implemented by fs? */
 433         unsigned no_lock:1;
 434
 435         /** Is access not implemented by fs? */
 436         unsigned no_access:1;
 437
 438         /** Is create not implemented by fs? */
 439         unsigned no_create:1;
 440
 441         /** Is interrupt not implemented by fs? */
 442         unsigned no_interrupt:1;
 443
 444         /** Is bmap not implemented by fs? */
 445         unsigned no_bmap:1;
 446
 447         /** Is poll not implemented by fs? */
 448         unsigned no_poll:1;
 449
 450         /** Do multi-page cached writes */
 451         unsigned big_writes:1;
 452
 453         /** Don't apply umask to creation modes */
 454         unsigned dont_mask:1;
 455
 456         /** The number of requests waiting for completion */
 457         atomic_t num_waiting;
 458
 459         /** Negotiated minor version */
 460         unsigned minor;
 461
 462         /** Backing dev info */
 463         struct backing_dev_info bdi;
 464
 465         /** Entry on the fuse_conn_list */
 466         struct list_head entry;
 467
 468         /** Device ID from super block */
 469         dev_t dev;
 470
 471         /** Dentries in the control filesystem */
 472         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 473
 474         /** number of dentries used in the above array */
 475         int ctl_ndents;
 476
 477         /** O_ASYNC requests */
 478         struct fasync_struct *fasync;
 479
 480         /** Key for lock owner ID scrambling */
 481         u32 scramble_key[4];
 482
 483         /** Reserved request for the DESTROY message */
 484         struct fuse_req *destroy_req;
 485
 486         /** Version counter for attribute changes */
 487         u64 attr_version;
 488
 489         /** Called on final put */
 490         void (*release)(struct fuse_conn *);
 491
 492         /** Super block for this connection. */
 493         struct super_block *sb;
 494
 495         /** Read/write semaphore to hold when accessing sb. */
 496         struct rw_semaphore killsb;
 497 };
 498
 499 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 500 {
 501         return sb->s_fs_info;
 502 }
 503
 504 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 505 {
 506         return get_fuse_conn_super(inode->i_sb);
 507 }
 508
 509 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 510 {
 511         return container_of(inode, struct fuse_inode, inode);
 512 }
 513
 514 static inline u64 get_node_id(struct inode *inode)
 515 {
 516         return get_fuse_inode(inode)->nodeid;
 517 }
 518
 519 /** Device operations */
 520 extern const struct file_operations fuse_dev_operations;
 521
 522 extern const struct dentry_operations fuse_dentry_operations;
 523
 524 /**
 525  * Inode to nodeid comparison.
 526  */
 527 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 528
 529 /**
 530  * Get a filled in inode
 531  */
 532 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 533                         int generation, struct fuse_attr *attr,
 534                         u64 attr_valid, u64 attr_version);
 535
 536 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 537                      struct fuse_entry_out *outarg, struct inode **inode);
 538
 539 /**
 540  * Send FORGET command
 541  */
 542 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 543                       u64 nodeid, u64 nlookup);
 544
 545 /**
 546  * Initialize READ or READDIR request
 547  */
 548 void fuse_read_fill(struct fuse_req *req, struct file *file,
 549                     loff_t pos, size_t count, int opcode);
 550
 551 /**
 552  * Send OPEN or OPENDIR request
 553  */
 554 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 555
 556 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 557 struct fuse_file *fuse_file_get(struct fuse_file *ff);
 558 void fuse_file_free(struct fuse_file *ff);
 559 void fuse_finish_open(struct inode *inode, struct file *file);
 560
 561 void fuse_sync_release(struct fuse_file *ff, int flags);
 562
 563 /**
 564  * Send RELEASE or RELEASEDIR request
 565  */
 566 void fuse_release_common(struct file *file, int opcode);
 567
 568 /**
 569  * Send FSYNC or FSYNCDIR request
 570  */
 571 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 572                       int isdir);
 573
 574 /**
 575  * Notify poll wakeup
 576  */
 577 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 578                             struct fuse_notify_poll_wakeup_out *outarg);
 579
 580 /**
 581  * Initialize file operations on a regular file
 582  */
 583 void fuse_init_file_inode(struct inode *inode);
 584
 585 /**
 586  * Initialize inode operations on regular files and special files
 587  */
 588 void fuse_init_common(struct inode *inode);
 589
 590 /**
 591  * Initialize inode and file operations on a directory
 592  */
 593 void fuse_init_dir(struct inode *inode);
 594
 595 /**
 596  * Initialize inode operations on a symlink
 597  */
 598 void fuse_init_symlink(struct inode *inode);
 599
 600 /**
 601  * Change attributes of an inode
 602  */
 603 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 604                             u64 attr_valid, u64 attr_version);
 605
 606 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 607                                    u64 attr_valid);
 608
 609 void fuse_truncate(struct address_space *mapping, loff_t offset);
 610
 611 /**
 612  * Initialize the client device
 613  */
 614 int fuse_dev_init(void);
 615
 616 /**
 617  * Cleanup the client device
 618  */
 619 void fuse_dev_cleanup(void);
 620
 621 int fuse_ctl_init(void);
 622 void fuse_ctl_cleanup(void);
 623
 624 /**
 625  * Allocate a request
 626  */
 627 struct fuse_req *fuse_request_alloc(void);
 628
 629 struct fuse_req *fuse_request_alloc_nofs(void);
 630
 631 /**
 632  * Free a request
 633  */
 634 void fuse_request_free(struct fuse_req *req);
 635
 636 /**
 637  * Get a request, may fail with -ENOMEM
 638  */
 639 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 640
 641 /**
 642  * Gets a requests for a file operation, always succeeds
 643  */
 644 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 645
 646 /**
 647  * Decrement reference count of a request.  If count goes to zero free
 648  * the request.
 649  */
 650 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 651
 652 /**
 653  * Send a request (synchronous)
 654  */
 655 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 656
 657 /**
 658  * Send a request with no reply
 659  */
 660 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 661
 662 /**
 663  * Send a request in the background
 664  */
 665 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 666
 667 void fuse_request_send_background_locked(struct fuse_conn *fc,
 668                                          struct fuse_req *req);
 669
 670 /* Abort all requests */
 671 void fuse_abort_conn(struct fuse_conn *fc);
 672
 673 /**
 674  * Invalidate inode attributes
 675  */
 676 void fuse_invalidate_attr(struct inode *inode);
 677
 678 void fuse_invalidate_entry_cache(struct dentry *entry);
 679
 680 /**
 681  * Acquire reference to fuse_conn
 682  */
 683 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 684
 685 void fuse_conn_kill(struct fuse_conn *fc);
 686
 687 /**
 688  * Initialize fuse_conn
 689  */
 690 void fuse_conn_init(struct fuse_conn *fc);
 691
 692 /**
 693  * Release reference to fuse_conn
 694  */
 695 void fuse_conn_put(struct fuse_conn *fc);
 696
 697 /**
 698  * Add connection to control filesystem
 699  */
 700 int fuse_ctl_add_conn(struct fuse_conn *fc);
 701
 702 /**
 703  * Remove connection from control filesystem
 704  */
 705 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 706
 707 /**
 708  * Is file type valid?
 709  */
 710 int fuse_valid_type(int m);
 711
 712 /**
 713  * Is task allowed to perform filesystem operation?
 714  */
 715 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
 716
 717 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 718
 719 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 720                            struct file *file, bool *refreshed);
 721
 722 void fuse_flush_writepages(struct inode *inode);
 723
 724 void fuse_set_nowrite(struct inode *inode);
 725 void fuse_release_nowrite(struct inode *inode);
 726
 727 u64 fuse_get_attr_version(struct fuse_conn *fc);
 728
 729 /**
 730  * File-system tells the kernel to invalidate cache for the given node id.
 731  */
 732 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 733                              loff_t offset, loff_t len);
 734
 735 /**
 736  * File-system tells the kernel to invalidate parent attributes and
 737  * the dentry matching parent/name.
 738  */
 739 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 740                              struct qstr *name);
 741
 742 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 743                  bool isdir);
 744 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 745                        size_t count, loff_t *ppos, int write);
 746 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 747                    unsigned int flags);
 748 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 749 int fuse_dev_release(struct inode *inode, struct file *file);
 750
 751 #endif /* _FS_FUSE_I_H */