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 {
 276                         struct fuse_read_in in;
 277                         u64 attr_ver;
 278                 } read;
 279                 struct {
 280                         struct fuse_write_in in;
 281                         struct fuse_write_out out;
 282                 } write;
 283                 struct fuse_notify_retrieve_in retrieve_in;
 284                 struct fuse_lk_in lk_in;
 285         } misc;
 286
 287         /** page vector */
 288         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 289
 290         /** number of pages in vector */
 291         unsigned num_pages;
 292
 293         /** offset of data on first page */
 294         unsigned page_offset;
 295
 296         /** File used in the request (or NULL) */
 297         struct fuse_file *ff;
 298
 299         /** Inode used in the request or NULL */
 300         struct inode *inode;
 301
 302         /** Link on fi->writepages */
 303         struct list_head writepages_entry;
 304
 305         /** Request completion callback */
 306         void (*end)(struct fuse_conn *, struct fuse_req *);
 307
 308         /** Request is stolen from fuse_file->reserved_req */
 309         struct file *stolen_file;
 310 };
 311
 312 /**
 313  * A Fuse connection.
 314  *
 315  * This structure is created, when the filesystem is mounted, and is
 316  * destroyed, when the client device is closed and the filesystem is
 317  * unmounted.
 318  */
 319 struct fuse_conn {
 320         /** Lock protecting accessess to  members of this structure */
 321         spinlock_t lock;
 322
 323         /** Mutex protecting against directory alias creation */
 324         struct mutex inst_mutex;
 325
 326         /** Refcount */
 327         atomic_t count;
 328
 329         /** The user id for this mount */
 330         uid_t user_id;
 331
 332         /** The group id for this mount */
 333         gid_t group_id;
 334
 335         /** The fuse mount flags for this mount */
 336         unsigned flags;
 337
 338         /** Maximum read size */
 339         unsigned max_read;
 340
 341         /** Maximum write size */
 342         unsigned max_write;
 343
 344         /** Readers of the connection are waiting on this */
 345         wait_queue_head_t waitq;
 346
 347         /** The list of pending requests */
 348         struct list_head pending;
 349
 350         /** The list of requests being processed */
 351         struct list_head processing;
 352
 353         /** The list of requests under I/O */
 354         struct list_head io;
 355
 356         /** The next unique kernel file handle */
 357         u64 khctr;
 358
 359         /** rbtree of fuse_files waiting for poll events indexed by ph */
 360         struct rb_root polled_files;
 361
 362         /** Maximum number of outstanding background requests */
 363         unsigned max_background;
 364
 365         /** Number of background requests at which congestion starts */
 366         unsigned congestion_threshold;
 367
 368         /** Number of requests currently in the background */
 369         unsigned num_background;
 370
 371         /** Number of background requests currently queued for userspace */
 372         unsigned active_background;
 373
 374         /** The list of background requests set aside for later queuing */
 375         struct list_head bg_queue;
 376
 377         /** Pending interrupts */
 378         struct list_head interrupts;
 379
 380         /** Queue of pending forgets */
 381         struct fuse_forget_link forget_list_head;
 382         struct fuse_forget_link *forget_list_tail;
 383
 384         /** Batching of FORGET requests (positive indicates FORGET batch) */
 385         int forget_batch;
 386
 387         /** Flag indicating if connection is blocked.  This will be
 388             the case before the INIT reply is received, and if there
 389             are too many outstading backgrounds requests */
 390         int blocked;
 391
 392         /** waitq for blocked connection */
 393         wait_queue_head_t blocked_waitq;
 394
 395         /** waitq for reserved requests */
 396         wait_queue_head_t reserved_req_waitq;
 397
 398         /** The next unique request id */
 399         u64 reqctr;
 400
 401         /** Connection established, cleared on umount, connection
 402             abort and device release */
 403         unsigned connected;
 404
 405         /** Connection failed (version mismatch).  Cannot race with
 406             setting other bitfields since it is only set once in INIT
 407             reply, before any other request, and never cleared */
 408         unsigned conn_error:1;
 409
 410         /** Connection successful.  Only set in INIT */
 411         unsigned conn_init:1;
 412
 413         /** Do readpages asynchronously?  Only set in INIT */
 414         unsigned async_read:1;
 415
 416         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 417         unsigned atomic_o_trunc:1;
 418
 419         /** Filesystem supports NFS exporting.  Only set in INIT */
 420         unsigned export_support:1;
 421
 422         /** Set if bdi is valid */
 423         unsigned bdi_initialized:1;
 424
 425         /*
 426          * The following bitfields are only for optimization purposes
 427          * and hence races in setting them will not cause malfunction
 428          */
 429
 430         /** Is fsync not implemented by fs? */
 431         unsigned no_fsync:1;
 432
 433         /** Is fsyncdir not implemented by fs? */
 434         unsigned no_fsyncdir:1;
 435
 436         /** Is flush not implemented by fs? */
 437         unsigned no_flush:1;
 438
 439         /** Is setxattr not implemented by fs? */
 440         unsigned no_setxattr:1;
 441
 442         /** Is getxattr not implemented by fs? */
 443         unsigned no_getxattr:1;
 444
 445         /** Is listxattr not implemented by fs? */
 446         unsigned no_listxattr:1;
 447
 448         /** Is removexattr not implemented by fs? */
 449         unsigned no_removexattr:1;
 450
 451         /** Are file locking primitives not implemented by fs? */
 452         unsigned no_lock:1;
 453
 454         /** Is access not implemented by fs? */
 455         unsigned no_access:1;
 456
 457         /** Is create not implemented by fs? */
 458         unsigned no_create:1;
 459
 460         /** Is interrupt not implemented by fs? */
 461         unsigned no_interrupt:1;
 462
 463         /** Is bmap not implemented by fs? */
 464         unsigned no_bmap:1;
 465
 466         /** Is poll not implemented by fs? */
 467         unsigned no_poll:1;
 468
 469         /** Do multi-page cached writes */
 470         unsigned big_writes:1;
 471
 472         /** Don't apply umask to creation modes */
 473         unsigned dont_mask:1;
 474
 475         /** The number of requests waiting for completion */
 476         atomic_t num_waiting;
 477
 478         /** Negotiated minor version */
 479         unsigned minor;
 480
 481         /** Backing dev info */
 482         struct backing_dev_info bdi;
 483
 484         /** Entry on the fuse_conn_list */
 485         struct list_head entry;
 486
 487         /** Device ID from super block */
 488         dev_t dev;
 489
 490         /** Dentries in the control filesystem */
 491         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 492
 493         /** number of dentries used in the above array */
 494         int ctl_ndents;
 495
 496         /** O_ASYNC requests */
 497         struct fasync_struct *fasync;
 498
 499         /** Key for lock owner ID scrambling */
 500         u32 scramble_key[4];
 501
 502         /** Reserved request for the DESTROY message */
 503         struct fuse_req *destroy_req;
 504
 505         /** Version counter for attribute changes */
 506         u64 attr_version;
 507
 508         /** Called on final put */
 509         void (*release)(struct fuse_conn *);
 510
 511         /** Super block for this connection. */
 512         struct super_block *sb;
 513
 514         /** Read/write semaphore to hold when accessing sb. */
 515         struct rw_semaphore killsb;
 516 };
 517
 518 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 519 {
 520         return sb->s_fs_info;
 521 }
 522
 523 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 524 {
 525         return get_fuse_conn_super(inode->i_sb);
 526 }
 527
 528 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 529 {
 530         return container_of(inode, struct fuse_inode, inode);
 531 }
 532
 533 static inline u64 get_node_id(struct inode *inode)
 534 {
 535         return get_fuse_inode(inode)->nodeid;
 536 }
 537
 538 /** Device operations */
 539 extern const struct file_operations fuse_dev_operations;
 540
 541 extern const struct dentry_operations fuse_dentry_operations;
 542
 543 /**
 544  * Inode to nodeid comparison.
 545  */
 546 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 547
 548 /**
 549  * Get a filled in inode
 550  */
 551 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 552                         int generation, struct fuse_attr *attr,
 553                         u64 attr_valid, u64 attr_version);
 554
 555 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 556                      struct fuse_entry_out *outarg, struct inode **inode);
 557
 558 /**
 559  * Send FORGET command
 560  */
 561 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 562                        u64 nodeid, u64 nlookup);
 563
 564 struct fuse_forget_link *fuse_alloc_forget(void);
 565
 566 /**
 567  * Initialize READ or READDIR request
 568  */
 569 void fuse_read_fill(struct fuse_req *req, struct file *file,
 570                     loff_t pos, size_t count, int opcode);
 571
 572 /**
 573  * Send OPEN or OPENDIR request
 574  */
 575 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 576
 577 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 578 struct fuse_file *fuse_file_get(struct fuse_file *ff);
 579 void fuse_file_free(struct fuse_file *ff);
 580 void fuse_finish_open(struct inode *inode, struct file *file);
 581
 582 void fuse_sync_release(struct fuse_file *ff, int flags);
 583
 584 /**
 585  * Send RELEASE or RELEASEDIR request
 586  */
 587 void fuse_release_common(struct file *file, int opcode);
 588
 589 /**
 590  * Send FSYNC or FSYNCDIR request
 591  */
 592 int fuse_fsync_common(struct file *file, int datasync, int isdir);
 593
 594 /**
 595  * Notify poll wakeup
 596  */
 597 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 598                             struct fuse_notify_poll_wakeup_out *outarg);
 599
 600 /**
 601  * Initialize file operations on a regular file
 602  */
 603 void fuse_init_file_inode(struct inode *inode);
 604
 605 /**
 606  * Initialize inode operations on regular files and special files
 607  */
 608 void fuse_init_common(struct inode *inode);
 609
 610 /**
 611  * Initialize inode and file operations on a directory
 612  */
 613 void fuse_init_dir(struct inode *inode);
 614
 615 /**
 616  * Initialize inode operations on a symlink
 617  */
 618 void fuse_init_symlink(struct inode *inode);
 619
 620 /**
 621  * Change attributes of an inode
 622  */
 623 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 624                             u64 attr_valid, u64 attr_version);
 625
 626 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 627                                    u64 attr_valid);
 628
 629 /**
 630  * Initialize the client device
 631  */
 632 int fuse_dev_init(void);
 633
 634 /**
 635  * Cleanup the client device
 636  */
 637 void fuse_dev_cleanup(void);
 638
 639 int fuse_ctl_init(void);
 640 void fuse_ctl_cleanup(void);
 641
 642 /**
 643  * Allocate a request
 644  */
 645 struct fuse_req *fuse_request_alloc(void);
 646
 647 struct fuse_req *fuse_request_alloc_nofs(void);
 648
 649 /**
 650  * Free a request
 651  */
 652 void fuse_request_free(struct fuse_req *req);
 653
 654 /**
 655  * Get a request, may fail with -ENOMEM
 656  */
 657 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 658
 659 /**
 660  * Gets a requests for a file operation, always succeeds
 661  */
 662 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 663
 664 /**
 665  * Decrement reference count of a request.  If count goes to zero free
 666  * the request.
 667  */
 668 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 669
 670 /**
 671  * Send a request (synchronous)
 672  */
 673 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 674
 675 /**
 676  * Send a request in the background
 677  */
 678 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 679
 680 void fuse_request_send_background_locked(struct fuse_conn *fc,
 681                                          struct fuse_req *req);
 682
 683 /* Abort all requests */
 684 void fuse_abort_conn(struct fuse_conn *fc);
 685
 686 /**
 687  * Invalidate inode attributes
 688  */
 689 void fuse_invalidate_attr(struct inode *inode);
 690
 691 void fuse_invalidate_entry_cache(struct dentry *entry);
 692
 693 /**
 694  * Acquire reference to fuse_conn
 695  */
 696 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 697
 698 void fuse_conn_kill(struct fuse_conn *fc);
 699
 700 /**
 701  * Initialize fuse_conn
 702  */
 703 void fuse_conn_init(struct fuse_conn *fc);
 704
 705 /**
 706  * Release reference to fuse_conn
 707  */
 708 void fuse_conn_put(struct fuse_conn *fc);
 709
 710 /**
 711  * Add connection to control filesystem
 712  */
 713 int fuse_ctl_add_conn(struct fuse_conn *fc);
 714
 715 /**
 716  * Remove connection from control filesystem
 717  */
 718 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 719
 720 /**
 721  * Is file type valid?
 722  */
 723 int fuse_valid_type(int m);
 724
 725 /**
 726  * Is task allowed to perform filesystem operation?
 727  */
 728 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
 729
 730 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 731
 732 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 733                            struct file *file, bool *refreshed);
 734
 735 void fuse_flush_writepages(struct inode *inode);
 736
 737 void fuse_set_nowrite(struct inode *inode);
 738 void fuse_release_nowrite(struct inode *inode);
 739
 740 u64 fuse_get_attr_version(struct fuse_conn *fc);
 741
 742 /**
 743  * File-system tells the kernel to invalidate cache for the given node id.
 744  */
 745 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 746                              loff_t offset, loff_t len);
 747
 748 /**
 749  * File-system tells the kernel to invalidate parent attributes and
 750  * the dentry matching parent/name.
 751  */
 752 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 753                              struct qstr *name);
 754
 755 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 756                  bool isdir);
 757 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 758                        size_t count, loff_t *ppos, int write);
 759 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 760                    unsigned int flags);
 761 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 762 int fuse_dev_release(struct inode *inode, struct file *file);
 763
 764 void fuse_write_update_size(struct inode *inode, loff_t pos);
 765
 766 #endif /* _FS_FUSE_I_H */