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         /** Pages may be replaced with new ones */
 181         unsigned page_replace:1;
 182
 183         /** Number or arguments */
 184         unsigned numargs;
 185
 186         /** Array of arguments */
 187         struct fuse_arg args[3];
 188 };
 189
 190 /** The request state */
 191 enum fuse_req_state {
 192         FUSE_REQ_INIT = 0,
 193         FUSE_REQ_PENDING,
 194         FUSE_REQ_READING,
 195         FUSE_REQ_SENT,
 196         FUSE_REQ_WRITING,
 197         FUSE_REQ_FINISHED
 198 };
 199
 200 /**
 201  * A request to the client
 202  */
 203 struct fuse_req {
 204         /** This can be on either pending processing or io lists in
 205             fuse_conn */
 206         struct list_head list;
 207
 208         /** Entry on the interrupts list  */
 209         struct list_head intr_entry;
 210
 211         /** refcount */
 212         atomic_t count;
 213
 214         /** Unique ID for the interrupt request */
 215         u64 intr_unique;
 216
 217         /*
 218          * The following bitfields are either set once before the
 219          * request is queued or setting/clearing them is protected by
 220          * fuse_conn->lock
 221          */
 222
 223         /** True if the request has reply */
 224         unsigned isreply:1;
 225
 226         /** Force sending of the request even if interrupted */
 227         unsigned force:1;
 228
 229         /** The request was aborted */
 230         unsigned aborted:1;
 231
 232         /** Request is sent in the background */
 233         unsigned background:1;
 234
 235         /** The request has been interrupted */
 236         unsigned interrupted:1;
 237
 238         /** Data is being copied to/from the request */
 239         unsigned locked:1;
 240
 241         /** Request is counted as "waiting" */
 242         unsigned waiting:1;
 243
 244         /** State of the request */
 245         enum fuse_req_state state;
 246
 247         /** The request input */
 248         struct fuse_in in;
 249
 250         /** The request output */
 251         struct fuse_out out;
 252
 253         /** Used to wake up the task waiting for completion of request*/
 254         wait_queue_head_t waitq;
 255
 256         /** Data for asynchronous requests */
 257         union {
 258                 struct fuse_forget_in forget_in;
 259                 struct {
 260                         struct fuse_release_in in;
 261                         struct path path;
 262                 } release;
 263                 struct fuse_init_in init_in;
 264                 struct fuse_init_out init_out;
 265                 struct cuse_init_in cuse_init_in;
 266                 struct cuse_init_out cuse_init_out;
 267                 struct {
 268                         struct fuse_read_in in;
 269                         u64 attr_ver;
 270                 } read;
 271                 struct {
 272                         struct fuse_write_in in;
 273                         struct fuse_write_out out;
 274                 } write;
 275                 struct fuse_notify_retrieve_in retrieve_in;
 276                 struct fuse_lk_in lk_in;
 277         } misc;
 278
 279         /** page vector */
 280         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 281
 282         /** number of pages in vector */
 283         unsigned num_pages;
 284
 285         /** offset of data on first page */
 286         unsigned page_offset;
 287
 288         /** File used in the request (or NULL) */
 289         struct fuse_file *ff;
 290
 291         /** Inode used in the request or NULL */
 292         struct inode *inode;
 293
 294         /** Link on fi->writepages */
 295         struct list_head writepages_entry;
 296
 297         /** Request completion callback */
 298         void (*end)(struct fuse_conn *, struct fuse_req *);
 299
 300         /** Request is stolen from fuse_file->reserved_req */
 301         struct file *stolen_file;
 302 };
 303
 304 /**
 305  * A Fuse connection.
 306  *
 307  * This structure is created, when the filesystem is mounted, and is
 308  * destroyed, when the client device is closed and the filesystem is
 309  * unmounted.
 310  */
 311 struct fuse_conn {
 312         /** Lock protecting accessess to  members of this structure */
 313         spinlock_t lock;
 314
 315         /** Mutex protecting against directory alias creation */
 316         struct mutex inst_mutex;
 317
 318         /** Refcount */
 319         atomic_t count;
 320
 321         /** The user id for this mount */
 322         uid_t user_id;
 323
 324         /** The group id for this mount */
 325         gid_t group_id;
 326
 327         /** The fuse mount flags for this mount */
 328         unsigned flags;
 329
 330         /** Maximum read size */
 331         unsigned max_read;
 332
 333         /** Maximum write size */
 334         unsigned max_write;
 335
 336         /** Readers of the connection are waiting on this */
 337         wait_queue_head_t waitq;
 338
 339         /** The list of pending requests */
 340         struct list_head pending;
 341
 342         /** The list of requests being processed */
 343         struct list_head processing;
 344
 345         /** The list of requests under I/O */
 346         struct list_head io;
 347
 348         /** The next unique kernel file handle */
 349         u64 khctr;
 350
 351         /** rbtree of fuse_files waiting for poll events indexed by ph */
 352         struct rb_root polled_files;
 353
 354         /** Maximum number of outstanding background requests */
 355         unsigned max_background;
 356
 357         /** Number of background requests at which congestion starts */
 358         unsigned congestion_threshold;
 359
 360         /** Number of requests currently in the background */
 361         unsigned num_background;
 362
 363         /** Number of background requests currently queued for userspace */
 364         unsigned active_background;
 365
 366         /** The list of background requests set aside for later queuing */
 367         struct list_head bg_queue;
 368
 369         /** Pending interrupts */
 370         struct list_head interrupts;
 371
 372         /** Flag indicating if connection is blocked.  This will be
 373             the case before the INIT reply is received, and if there
 374             are too many outstading backgrounds requests */
 375         int blocked;
 376
 377         /** waitq for blocked connection */
 378         wait_queue_head_t blocked_waitq;
 379
 380         /** waitq for reserved requests */
 381         wait_queue_head_t reserved_req_waitq;
 382
 383         /** The next unique request id */
 384         u64 reqctr;
 385
 386         /** Connection established, cleared on umount, connection
 387             abort and device release */
 388         unsigned connected;
 389
 390         /** Connection failed (version mismatch).  Cannot race with
 391             setting other bitfields since it is only set once in INIT
 392             reply, before any other request, and never cleared */
 393         unsigned conn_error:1;
 394
 395         /** Connection successful.  Only set in INIT */
 396         unsigned conn_init:1;
 397
 398         /** Do readpages asynchronously?  Only set in INIT */
 399         unsigned async_read:1;
 400
 401         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 402         unsigned atomic_o_trunc:1;
 403
 404         /** Filesystem supports NFS exporting.  Only set in INIT */
 405         unsigned export_support:1;
 406
 407         /** Set if bdi is valid */
 408         unsigned bdi_initialized:1;
 409
 410         /*
 411          * The following bitfields are only for optimization purposes
 412          * and hence races in setting them will not cause malfunction
 413          */
 414
 415         /** Is fsync not implemented by fs? */
 416         unsigned no_fsync:1;
 417
 418         /** Is fsyncdir not implemented by fs? */
 419         unsigned no_fsyncdir:1;
 420
 421         /** Is flush not implemented by fs? */
 422         unsigned no_flush:1;
 423
 424         /** Is setxattr not implemented by fs? */
 425         unsigned no_setxattr:1;
 426
 427         /** Is getxattr not implemented by fs? */
 428         unsigned no_getxattr:1;
 429
 430         /** Is listxattr not implemented by fs? */
 431         unsigned no_listxattr:1;
 432
 433         /** Is removexattr not implemented by fs? */
 434         unsigned no_removexattr:1;
 435
 436         /** Are file locking primitives not implemented by fs? */
 437         unsigned no_lock:1;
 438
 439         /** Is access not implemented by fs? */
 440         unsigned no_access:1;
 441
 442         /** Is create not implemented by fs? */
 443         unsigned no_create:1;
 444
 445         /** Is interrupt not implemented by fs? */
 446         unsigned no_interrupt:1;
 447
 448         /** Is bmap not implemented by fs? */
 449         unsigned no_bmap:1;
 450
 451         /** Is poll not implemented by fs? */
 452         unsigned no_poll:1;
 453
 454         /** Do multi-page cached writes */
 455         unsigned big_writes:1;
 456
 457         /** Don't apply umask to creation modes */
 458         unsigned dont_mask:1;
 459
 460         /** The number of requests waiting for completion */
 461         atomic_t num_waiting;
 462
 463         /** Negotiated minor version */
 464         unsigned minor;
 465
 466         /** Backing dev info */
 467         struct backing_dev_info bdi;
 468
 469         /** Entry on the fuse_conn_list */
 470         struct list_head entry;
 471
 472         /** Device ID from super block */
 473         dev_t dev;
 474
 475         /** Dentries in the control filesystem */
 476         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 477
 478         /** number of dentries used in the above array */
 479         int ctl_ndents;
 480
 481         /** O_ASYNC requests */
 482         struct fasync_struct *fasync;
 483
 484         /** Key for lock owner ID scrambling */
 485         u32 scramble_key[4];
 486
 487         /** Reserved request for the DESTROY message */
 488         struct fuse_req *destroy_req;
 489
 490         /** Version counter for attribute changes */
 491         u64 attr_version;
 492
 493         /** Called on final put */
 494         void (*release)(struct fuse_conn *);
 495
 496         /** Super block for this connection. */
 497         struct super_block *sb;
 498
 499         /** Read/write semaphore to hold when accessing sb. */
 500         struct rw_semaphore killsb;
 501 };
 502
 503 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 504 {
 505         return sb->s_fs_info;
 506 }
 507
 508 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 509 {
 510         return get_fuse_conn_super(inode->i_sb);
 511 }
 512
 513 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 514 {
 515         return container_of(inode, struct fuse_inode, inode);
 516 }
 517
 518 static inline u64 get_node_id(struct inode *inode)
 519 {
 520         return get_fuse_inode(inode)->nodeid;
 521 }
 522
 523 /** Device operations */
 524 extern const struct file_operations fuse_dev_operations;
 525
 526 extern const struct dentry_operations fuse_dentry_operations;
 527
 528 /**
 529  * Inode to nodeid comparison.
 530  */
 531 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 532
 533 /**
 534  * Get a filled in inode
 535  */
 536 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 537                         int generation, struct fuse_attr *attr,
 538                         u64 attr_valid, u64 attr_version);
 539
 540 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 541                      struct fuse_entry_out *outarg, struct inode **inode);
 542
 543 /**
 544  * Send FORGET command
 545  */
 546 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 547                       u64 nodeid, u64 nlookup);
 548
 549 /**
 550  * Initialize READ or READDIR request
 551  */
 552 void fuse_read_fill(struct fuse_req *req, struct file *file,
 553                     loff_t pos, size_t count, int opcode);
 554
 555 /**
 556  * Send OPEN or OPENDIR request
 557  */
 558 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 559
 560 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 561 struct fuse_file *fuse_file_get(struct fuse_file *ff);
 562 void fuse_file_free(struct fuse_file *ff);
 563 void fuse_finish_open(struct inode *inode, struct file *file);
 564
 565 void fuse_sync_release(struct fuse_file *ff, int flags);
 566
 567 /**
 568  * Send RELEASE or RELEASEDIR request
 569  */
 570 void fuse_release_common(struct file *file, int opcode);
 571
 572 /**
 573  * Send FSYNC or FSYNCDIR request
 574  */
 575 int fuse_fsync_common(struct file *file, int datasync, int isdir);
 576
 577 /**
 578  * Notify poll wakeup
 579  */
 580 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 581                             struct fuse_notify_poll_wakeup_out *outarg);
 582
 583 /**
 584  * Initialize file operations on a regular file
 585  */
 586 void fuse_init_file_inode(struct inode *inode);
 587
 588 /**
 589  * Initialize inode operations on regular files and special files
 590  */
 591 void fuse_init_common(struct inode *inode);
 592
 593 /**
 594  * Initialize inode and file operations on a directory
 595  */
 596 void fuse_init_dir(struct inode *inode);
 597
 598 /**
 599  * Initialize inode operations on a symlink
 600  */
 601 void fuse_init_symlink(struct inode *inode);
 602
 603 /**
 604  * Change attributes of an inode
 605  */
 606 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 607                             u64 attr_valid, u64 attr_version);
 608
 609 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 610                                    u64 attr_valid);
 611
 612 /**
 613  * Initialize the client device
 614  */
 615 int fuse_dev_init(void);
 616
 617 /**
 618  * Cleanup the client device
 619  */
 620 void fuse_dev_cleanup(void);
 621
 622 int fuse_ctl_init(void);
 623 void fuse_ctl_cleanup(void);
 624
 625 /**
 626  * Allocate a request
 627  */
 628 struct fuse_req *fuse_request_alloc(void);
 629
 630 struct fuse_req *fuse_request_alloc_nofs(void);
 631
 632 /**
 633  * Free a request
 634  */
 635 void fuse_request_free(struct fuse_req *req);
 636
 637 /**
 638  * Get a request, may fail with -ENOMEM
 639  */
 640 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 641
 642 /**
 643  * Gets a requests for a file operation, always succeeds
 644  */
 645 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 646
 647 /**
 648  * Decrement reference count of a request.  If count goes to zero free
 649  * the request.
 650  */
 651 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 652
 653 /**
 654  * Send a request (synchronous)
 655  */
 656 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 657
 658 /**
 659  * Send a request with no reply
 660  */
 661 void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 662
 663 /**
 664  * Send a request in the background
 665  */
 666 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 667
 668 void fuse_request_send_background_locked(struct fuse_conn *fc,
 669                                          struct fuse_req *req);
 670
 671 /* Abort all requests */
 672 void fuse_abort_conn(struct fuse_conn *fc);
 673
 674 /**
 675  * Invalidate inode attributes
 676  */
 677 void fuse_invalidate_attr(struct inode *inode);
 678
 679 void fuse_invalidate_entry_cache(struct dentry *entry);
 680
 681 /**
 682  * Acquire reference to fuse_conn
 683  */
 684 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 685
 686 void fuse_conn_kill(struct fuse_conn *fc);
 687
 688 /**
 689  * Initialize fuse_conn
 690  */
 691 void fuse_conn_init(struct fuse_conn *fc);
 692
 693 /**
 694  * Release reference to fuse_conn
 695  */
 696 void fuse_conn_put(struct fuse_conn *fc);
 697
 698 /**
 699  * Add connection to control filesystem
 700  */
 701 int fuse_ctl_add_conn(struct fuse_conn *fc);
 702
 703 /**
 704  * Remove connection from control filesystem
 705  */
 706 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 707
 708 /**
 709  * Is file type valid?
 710  */
 711 int fuse_valid_type(int m);
 712
 713 /**
 714  * Is task allowed to perform filesystem operation?
 715  */
 716 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
 717
 718 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 719
 720 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 721                            struct file *file, bool *refreshed);
 722
 723 void fuse_flush_writepages(struct inode *inode);
 724
 725 void fuse_set_nowrite(struct inode *inode);
 726 void fuse_release_nowrite(struct inode *inode);
 727
 728 u64 fuse_get_attr_version(struct fuse_conn *fc);
 729
 730 /**
 731  * File-system tells the kernel to invalidate cache for the given node id.
 732  */
 733 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 734                              loff_t offset, loff_t len);
 735
 736 /**
 737  * File-system tells the kernel to invalidate parent attributes and
 738  * the dentry matching parent/name.
 739  */
 740 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 741                              struct qstr *name);
 742
 743 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 744                  bool isdir);
 745 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 746                        size_t count, loff_t *ppos, int write);
 747 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 748                    unsigned int flags);
 749 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 750 int fuse_dev_release(struct inode *inode, struct file *file);
 751
 752 void fuse_write_update_size(struct inode *inode, loff_t pos);
 753
 754 #endif /* _FS_FUSE_I_H */