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