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 #include <linux/workqueue.h>
  25
  26 /** Max number of pages that can be used in a single read request */
  27 #define FUSE_MAX_PAGES_PER_REQ 32
  28
  29 /** Bias for fi->writectr, meaning new writepages must not be sent */
  30 #define FUSE_NOWRITE INT_MIN
  31
  32 /** It could be as large as PATH_MAX, but would that have any uses? */
  33 #define FUSE_NAME_MAX 1024
  34
  35 /** Number of dentries for each connection in the control filesystem */
  36 #define FUSE_CTL_NUM_DENTRIES 5
  37
  38 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
  39     module will check permissions based on the file mode.  Otherwise no
  40     permission checking is done in the kernel */
  41 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
  42
  43 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
  44     doing the mount will be allowed to access the filesystem */
  45 #define FUSE_ALLOW_OTHER         (1 << 1)
  46
  47 /** List of active connections */
  48 extern struct list_head fuse_conn_list;
  49
  50 /** Global mutex protecting fuse_conn_list and the control filesystem */
  51 extern struct mutex fuse_mutex;
  52
  53 /** Module parameters */
  54 extern unsigned max_user_bgreq;
  55 extern unsigned max_user_congthresh;
  56
  57 /* One forget request */
  58 struct fuse_forget_link {
  59         struct fuse_forget_one forget_one;
  60         struct fuse_forget_link *next;
  61 };
  62
  63 /** FUSE inode */
  64 struct fuse_inode {
  65         /** Inode data */
  66         struct inode inode;
  67
  68         /** Unique ID, which identifies the inode between userspace
  69          * and kernel */
  70         u64 nodeid;
  71
  72         /** Number of lookups on this inode */
  73         u64 nlookup;
  74
  75         /** The request used for sending the FORGET message */
  76         struct fuse_forget_link *forget;
  77
  78         /** Time in jiffies until the file attributes are valid */
  79         u64 i_time;
  80
  81         /** The sticky bit in inode->i_mode may have been removed, so
  82             preserve the original mode */
  83         mode_t orig_i_mode;
  84
  85         /** Version of last attribute change */
  86         u64 attr_version;
  87
  88         /** Files usable in writepage.  Protected by fc->lock */
  89         struct list_head write_files;
  90
  91         /** Writepages pending on truncate or fsync */
  92         struct list_head queued_writes;
  93
  94         /** Number of sent writes, a negative bias (FUSE_NOWRITE)
  95          * means more writes are blocked */
  96         int writectr;
  97
  98         /** Waitq for writepage completion */
  99         wait_queue_head_t page_waitq;
 100
 101         /** List of writepage requestst (pending or sent) */
 102         struct list_head writepages;
 103 };
 104
 105 struct fuse_conn;
 106
 107 /** FUSE specific file data */
 108 struct fuse_file {
 109         /** Fuse connection for this file */
 110         struct fuse_conn *fc;
 111
 112         /** Request reserved for flush and release */
 113         struct fuse_req *reserved_req;
 114
 115         /** Kernel file handle guaranteed to be unique */
 116         u64 kh;
 117
 118         /** File handle used by userspace */
 119         u64 fh;
 120
 121         /** Node id of this file */
 122         u64 nodeid;
 123
 124         /** Refcount */
 125         atomic_t count;
 126
 127         /** FOPEN_* flags returned by open */
 128         u32 open_flags;
 129
 130         /** Entry on inode's write_files list */
 131         struct list_head write_entry;
 132
 133         /** RB node to be linked on fuse_conn->polled_files */
 134         struct rb_node polled_node;
 135
 136         /** Wait queue head for poll */
 137         wait_queue_head_t poll_wait;
 138 };
 139
 140 /** One input argument of a request */
 141 struct fuse_in_arg {
 142         unsigned size;
 143         const void *value;
 144 };
 145
 146 /** The request input */
 147 struct fuse_in {
 148         /** The request header */
 149         struct fuse_in_header h;
 150
 151         /** True if the data for the last argument is in req->pages */
 152         unsigned argpages:1;
 153
 154         /** Number of arguments */
 155         unsigned numargs;
 156
 157         /** Array of arguments */
 158         struct fuse_in_arg args[3];
 159 };
 160
 161 /** One output argument of a request */
 162 struct fuse_arg {
 163         unsigned size;
 164         void *value;
 165 };
 166
 167 /** The request output */
 168 struct fuse_out {
 169         /** Header returned from userspace */
 170         struct fuse_out_header h;
 171
 172         /*
 173          * The following bitfields are not changed during the request
 174          * processing
 175          */
 176
 177         /** Last argument is variable length (can be shorter than
 178             arg->size) */
 179         unsigned argvar:1;
 180
 181         /** Last argument is a list of pages to copy data to */
 182         unsigned argpages:1;
 183
 184         /** Zero partially or not copied pages */
 185         unsigned page_zeroing:1;
 186
 187         /** Pages may be replaced with new ones */
 188         unsigned page_replace:1;
 189
 190         /** Number or arguments */
 191         unsigned numargs;
 192
 193         /** Array of arguments */
 194         struct fuse_arg args[3];
 195 };
 196
 197 /** The request state */
 198 enum fuse_req_state {
 199         FUSE_REQ_INIT = 0,
 200         FUSE_REQ_PENDING,
 201         FUSE_REQ_READING,
 202         FUSE_REQ_SENT,
 203         FUSE_REQ_WRITING,
 204         FUSE_REQ_FINISHED
 205 };
 206
 207 /**
 208  * A request to the client
 209  */
 210 struct fuse_req {
 211         /** This can be on either pending processing or io lists in
 212             fuse_conn */
 213         struct list_head list;
 214
 215         /** Entry on the interrupts list  */
 216         struct list_head intr_entry;
 217
 218         /** refcount */
 219         atomic_t count;
 220
 221         /** Unique ID for the interrupt request */
 222         u64 intr_unique;
 223
 224         /*
 225          * The following bitfields are either set once before the
 226          * request is queued or setting/clearing them is protected by
 227          * fuse_conn->lock
 228          */
 229
 230         /** True if the request has reply */
 231         unsigned isreply:1;
 232
 233         /** Force sending of the request even if interrupted */
 234         unsigned force:1;
 235
 236         /** The request was aborted */
 237         unsigned aborted:1;
 238
 239         /** Request is sent in the background */
 240         unsigned background:1;
 241
 242         /** The request has been interrupted */
 243         unsigned interrupted:1;
 244
 245         /** Data is being copied to/from the request */
 246         unsigned locked:1;
 247
 248         /** Request is counted as "waiting" */
 249         unsigned waiting:1;
 250
 251         /** State of the request */
 252         enum fuse_req_state state;
 253
 254         /** The request input */
 255         struct fuse_in in;
 256
 257         /** The request output */
 258         struct fuse_out out;
 259
 260         /** Used to wake up the task waiting for completion of request*/
 261         wait_queue_head_t waitq;
 262
 263         /** Data for asynchronous requests */
 264         union {
 265                 struct {
 266                         union {
 267                                 struct fuse_release_in in;
 268                                 struct work_struct work;
 269                         };
 270                         struct path path;
 271                 } release;
 272                 struct fuse_init_in init_in;
 273                 struct fuse_init_out init_out;
 274                 struct cuse_init_in cuse_init_in;
 275                 struct cuse_init_out cuse_init_out;
 276                 struct {
 277                         struct fuse_read_in in;
 278                         u64 attr_ver;
 279                 } read;
 280                 struct {
 281                         struct fuse_write_in in;
 282                         struct fuse_write_out out;
 283                 } write;
 284                 struct fuse_notify_retrieve_in retrieve_in;
 285                 struct fuse_lk_in lk_in;
 286         } misc;
 287
 288         /** page vector */
 289         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 290
 291         /** number of pages in vector */
 292         unsigned num_pages;
 293
 294         /** offset of data on first page */
 295         unsigned page_offset;
 296
 297         /** File used in the request (or NULL) */
 298         struct fuse_file *ff;
 299
 300         /** Inode used in the request or NULL */
 301         struct inode *inode;
 302
 303         /** Link on fi->writepages */
 304         struct list_head writepages_entry;
 305
 306         /** Request completion callback */
 307         void (*end)(struct fuse_conn *, struct fuse_req *);
 308
 309         /** Request is stolen from fuse_file->reserved_req */
 310         struct file *stolen_file;
 311 };
 312
 313 /**
 314  * A Fuse connection.
 315  *
 316  * This structure is created, when the filesystem is mounted, and is
 317  * destroyed, when the client device is closed and the filesystem is
 318  * unmounted.
 319  */
 320 struct fuse_conn {
 321         /** Lock protecting accessess to  members of this structure */
 322         spinlock_t lock;
 323
 324         /** Mutex protecting against directory alias creation */
 325         struct mutex inst_mutex;
 326
 327         /** Refcount */
 328         atomic_t count;
 329
 330         /** The user id for this mount */
 331         uid_t user_id;
 332
 333         /** The group id for this mount */
 334         gid_t group_id;
 335
 336         /** The fuse mount flags for this mount */
 337         unsigned flags;
 338
 339         /** Maximum read size */
 340         unsigned max_read;
 341
 342         /** Maximum write size */
 343         unsigned max_write;
 344
 345         /** Readers of the connection are waiting on this */
 346         wait_queue_head_t waitq;
 347
 348         /** The list of pending requests */
 349         struct list_head pending;
 350
 351         /** The list of requests being processed */
 352         struct list_head processing;
 353
 354         /** The list of requests under I/O */
 355         struct list_head io;
 356
 357         /** The next unique kernel file handle */
 358         u64 khctr;
 359
 360         /** rbtree of fuse_files waiting for poll events indexed by ph */
 361         struct rb_root polled_files;
 362
 363         /** Maximum number of outstanding background requests */
 364         unsigned max_background;
 365
 366         /** Number of background requests at which congestion starts */
 367         unsigned congestion_threshold;
 368
 369         /** Number of requests currently in the background */
 370         unsigned num_background;
 371
 372         /** Number of background requests currently queued for userspace */
 373         unsigned active_background;
 374
 375         /** The list of background requests set aside for later queuing */
 376         struct list_head bg_queue;
 377
 378         /** Pending interrupts */
 379         struct list_head interrupts;
 380
 381         /** Queue of pending forgets */
 382         struct fuse_forget_link forget_list_head;
 383         struct fuse_forget_link *forget_list_tail;
 384
 385         /** Batching of FORGET requests (positive indicates FORGET batch) */
 386         int forget_batch;
 387
 388         /** Flag indicating if connection is blocked.  This will be
 389             the case before the INIT reply is received, and if there
 390             are too many outstading backgrounds requests */
 391         int blocked;
 392
 393         /** waitq for blocked connection */
 394         wait_queue_head_t blocked_waitq;
 395
 396         /** waitq for reserved requests */
 397         wait_queue_head_t reserved_req_waitq;
 398
 399         /** The next unique request id */
 400         u64 reqctr;
 401
 402         /** Connection established, cleared on umount, connection
 403             abort and device release */
 404         unsigned connected;
 405
 406         /** Connection failed (version mismatch).  Cannot race with
 407             setting other bitfields since it is only set once in INIT
 408             reply, before any other request, and never cleared */
 409         unsigned conn_error:1;
 410
 411         /** Connection successful.  Only set in INIT */
 412         unsigned conn_init:1;
 413
 414         /** Do readpages asynchronously?  Only set in INIT */
 415         unsigned async_read:1;
 416
 417         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 418         unsigned atomic_o_trunc:1;
 419
 420         /** Filesystem supports NFS exporting.  Only set in INIT */
 421         unsigned export_support:1;
 422
 423         /** Set if bdi is valid */
 424         unsigned bdi_initialized:1;
 425
 426         /*
 427          * The following bitfields are only for optimization purposes
 428          * and hence races in setting them will not cause malfunction
 429          */
 430
 431         /** Is fsync not implemented by fs? */
 432         unsigned no_fsync:1;
 433
 434         /** Is fsyncdir not implemented by fs? */
 435         unsigned no_fsyncdir:1;
 436
 437         /** Is flush not implemented by fs? */
 438         unsigned no_flush:1;
 439
 440         /** Is setxattr not implemented by fs? */
 441         unsigned no_setxattr:1;
 442
 443         /** Is getxattr not implemented by fs? */
 444         unsigned no_getxattr:1;
 445
 446         /** Is listxattr not implemented by fs? */
 447         unsigned no_listxattr:1;
 448
 449         /** Is removexattr not implemented by fs? */
 450         unsigned no_removexattr:1;
 451
 452         /** Are file locking primitives not implemented by fs? */
 453         unsigned no_lock:1;
 454
 455         /** Is access not implemented by fs? */
 456         unsigned no_access:1;
 457
 458         /** Is create not implemented by fs? */
 459         unsigned no_create:1;
 460
 461         /** Is interrupt not implemented by fs? */
 462         unsigned no_interrupt:1;
 463
 464         /** Is bmap not implemented by fs? */
 465         unsigned no_bmap:1;
 466
 467         /** Is poll not implemented by fs? */
 468         unsigned no_poll:1;
 469
 470         /** Do multi-page cached writes */
 471         unsigned big_writes:1;
 472
 473         /** Don't apply umask to creation modes */
 474         unsigned dont_mask:1;
 475
 476         /** The number of requests waiting for completion */
 477         atomic_t num_waiting;
 478
 479         /** Negotiated minor version */
 480         unsigned minor;
 481
 482         /** Backing dev info */
 483         struct backing_dev_info bdi;
 484
 485         /** Entry on the fuse_conn_list */
 486         struct list_head entry;
 487
 488         /** Device ID from super block */
 489         dev_t dev;
 490
 491         /** Dentries in the control filesystem */
 492         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 493
 494         /** number of dentries used in the above array */
 495         int ctl_ndents;
 496
 497         /** O_ASYNC requests */
 498         struct fasync_struct *fasync;
 499
 500         /** Key for lock owner ID scrambling */
 501         u32 scramble_key[4];
 502
 503         /** Reserved request for the DESTROY message */
 504         struct fuse_req *destroy_req;
 505
 506         /** Version counter for attribute changes */
 507         u64 attr_version;
 508
 509         /** Called on final put */
 510         void (*release)(struct fuse_conn *);
 511
 512         /** Super block for this connection. */
 513         struct super_block *sb;
 514
 515         /** Read/write semaphore to hold when accessing sb. */
 516         struct rw_semaphore killsb;
 517 };
 518
 519 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 520 {
 521         return sb->s_fs_info;
 522 }
 523
 524 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 525 {
 526         return get_fuse_conn_super(inode->i_sb);
 527 }
 528
 529 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 530 {
 531         return container_of(inode, struct fuse_inode, inode);
 532 }
 533
 534 static inline u64 get_node_id(struct inode *inode)
 535 {
 536         return get_fuse_inode(inode)->nodeid;
 537 }
 538
 539 /** Device operations */
 540 extern const struct file_operations fuse_dev_operations;
 541
 542 extern const struct dentry_operations fuse_dentry_operations;
 543
 544 /**
 545  * Inode to nodeid comparison.
 546  */
 547 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 548
 549 /**
 550  * Get a filled in inode
 551  */
 552 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 553                         int generation, struct fuse_attr *attr,
 554                         u64 attr_valid, u64 attr_version);
 555
 556 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 557                      struct fuse_entry_out *outarg, struct inode **inode);
 558
 559 /**
 560  * Send FORGET command
 561  */
 562 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 563                        u64 nodeid, u64 nlookup);
 564
 565 struct fuse_forget_link *fuse_alloc_forget(void);
 566
 567 /**
 568  * Initialize READ or READDIR request
 569  */
 570 void fuse_read_fill(struct fuse_req *req, struct file *file,
 571                     loff_t pos, size_t count, int opcode);
 572
 573 /**
 574  * Send OPEN or OPENDIR request
 575  */
 576 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 577
 578 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 579 struct fuse_file *fuse_file_get(struct fuse_file *ff);
 580 void fuse_file_free(struct fuse_file *ff);
 581 void fuse_finish_open(struct inode *inode, struct file *file);
 582
 583 void fuse_sync_release(struct fuse_file *ff, int flags);
 584
 585 /**
 586  * Send RELEASE or RELEASEDIR request
 587  */
 588 void fuse_release_common(struct file *file, int opcode);
 589
 590 /**
 591  * Send FSYNC or FSYNCDIR request
 592  */
 593 int fuse_fsync_common(struct file *file, int datasync, int isdir);
 594
 595 /**
 596  * Notify poll wakeup
 597  */
 598 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 599                             struct fuse_notify_poll_wakeup_out *outarg);
 600
 601 /**
 602  * Initialize file operations on a regular file
 603  */
 604 void fuse_init_file_inode(struct inode *inode);
 605
 606 /**
 607  * Initialize inode operations on regular files and special files
 608  */
 609 void fuse_init_common(struct inode *inode);
 610
 611 /**
 612  * Initialize inode and file operations on a directory
 613  */
 614 void fuse_init_dir(struct inode *inode);
 615
 616 /**
 617  * Initialize inode operations on a symlink
 618  */
 619 void fuse_init_symlink(struct inode *inode);
 620
 621 /**
 622  * Change attributes of an inode
 623  */
 624 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 625                             u64 attr_valid, u64 attr_version);
 626
 627 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 628                                    u64 attr_valid);
 629
 630 /**
 631  * Initialize the client device
 632  */
 633 int fuse_dev_init(void);
 634
 635 /**
 636  * Cleanup the client device
 637  */
 638 void fuse_dev_cleanup(void);
 639
 640 int fuse_ctl_init(void);
 641 void fuse_ctl_cleanup(void);
 642
 643 /**
 644  * Allocate a request
 645  */
 646 struct fuse_req *fuse_request_alloc(void);
 647
 648 struct fuse_req *fuse_request_alloc_nofs(void);
 649
 650 /**
 651  * Free a request
 652  */
 653 void fuse_request_free(struct fuse_req *req);
 654
 655 /**
 656  * Get a request, may fail with -ENOMEM
 657  */
 658 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 659
 660 /**
 661  * Gets a requests for a file operation, always succeeds
 662  */
 663 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 664
 665 /**
 666  * Decrement reference count of a request.  If count goes to zero free
 667  * the request.
 668  */
 669 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 670
 671 /**
 672  * Send a request (synchronous)
 673  */
 674 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 675
 676 /**
 677  * Send a request in the background
 678  */
 679 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 680
 681 void fuse_request_send_background_locked(struct fuse_conn *fc,
 682                                          struct fuse_req *req);
 683
 684 /* Abort all requests */
 685 void fuse_abort_conn(struct fuse_conn *fc);
 686
 687 /**
 688  * Invalidate inode attributes
 689  */
 690 void fuse_invalidate_attr(struct inode *inode);
 691
 692 void fuse_invalidate_entry_cache(struct dentry *entry);
 693
 694 /**
 695  * Acquire reference to fuse_conn
 696  */
 697 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 698
 699 void fuse_conn_kill(struct fuse_conn *fc);
 700
 701 /**
 702  * Initialize fuse_conn
 703  */
 704 void fuse_conn_init(struct fuse_conn *fc);
 705
 706 /**
 707  * Release reference to fuse_conn
 708  */
 709 void fuse_conn_put(struct fuse_conn *fc);
 710
 711 /**
 712  * Add connection to control filesystem
 713  */
 714 int fuse_ctl_add_conn(struct fuse_conn *fc);
 715
 716 /**
 717  * Remove connection from control filesystem
 718  */
 719 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 720
 721 /**
 722  * Is file type valid?
 723  */
 724 int fuse_valid_type(int m);
 725
 726 /**
 727  * Is task allowed to perform filesystem operation?
 728  */
 729 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
 730
 731 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 732
 733 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 734                            struct file *file, bool *refreshed);
 735
 736 void fuse_flush_writepages(struct inode *inode);
 737
 738 void fuse_set_nowrite(struct inode *inode);
 739 void fuse_release_nowrite(struct inode *inode);
 740
 741 u64 fuse_get_attr_version(struct fuse_conn *fc);
 742
 743 /**
 744  * File-system tells the kernel to invalidate cache for the given node id.
 745  */
 746 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 747                              loff_t offset, loff_t len);
 748
 749 /**
 750  * File-system tells the kernel to invalidate parent attributes and
 751  * the dentry matching parent/name.
 752  */
 753 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 754                              struct qstr *name);
 755
 756 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 757                  bool isdir);
 758 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 759                        size_t count, loff_t *ppos, int write);
 760 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 761                    unsigned int flags);
 762 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 763 int fuse_dev_release(struct inode *inode, struct file *file);
 764
 765 void fuse_write_update_size(struct inode *inode, loff_t pos);
 766
 767 #endif /* _FS_FUSE_I_H */