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         umode_t orig_i_mode;
  84
  85         /** 64 bit inode number */
  86         u64 orig_ino;
  87
  88         /** Version of last attribute change */
  89         u64 attr_version;
  90
  91         /** Files usable in writepage.  Protected by fc->lock */
  92         struct list_head write_files;
  93
  94         /** Writepages pending on truncate or fsync */
  95         struct list_head queued_writes;
  96
  97         /** Number of sent writes, a negative bias (FUSE_NOWRITE)
  98          * means more writes are blocked */
  99         int writectr;
 100
 101         /** Waitq for writepage completion */
 102         wait_queue_head_t page_waitq;
 103
 104         /** List of writepage requestst (pending or sent) */
 105         struct list_head writepages;
 106 };
 107
 108 struct fuse_conn;
 109
 110 /** FUSE specific file data */
 111 struct fuse_file {
 112         /** Fuse connection for this file */
 113         struct fuse_conn *fc;
 114
 115         /** Request reserved for flush and release */
 116         struct fuse_req *reserved_req;
 117
 118         /** Kernel file handle guaranteed to be unique */
 119         u64 kh;
 120
 121         /** File handle used by userspace */
 122         u64 fh;
 123
 124         /** Node id of this file */
 125         u64 nodeid;
 126
 127         /** Refcount */
 128         atomic_t count;
 129
 130         /** FOPEN_* flags returned by open */
 131         u32 open_flags;
 132
 133         /** Entry on inode's write_files list */
 134         struct list_head write_entry;
 135
 136         /** RB node to be linked on fuse_conn->polled_files */
 137         struct rb_node polled_node;
 138
 139         /** Wait queue head for poll */
 140         wait_queue_head_t poll_wait;
 141
 142         /** Has flock been performed on this file? */
 143         bool flock:1;
 144 };
 145
 146 /** One input argument of a request */
 147 struct fuse_in_arg {
 148         unsigned size;
 149         const void *value;
 150 };
 151
 152 /** The request input */
 153 struct fuse_in {
 154         /** The request header */
 155         struct fuse_in_header h;
 156
 157         /** True if the data for the last argument is in req->pages */
 158         unsigned argpages:1;
 159
 160         /** Number of arguments */
 161         unsigned numargs;
 162
 163         /** Array of arguments */
 164         struct fuse_in_arg args[3];
 165 };
 166
 167 /** One output argument of a request */
 168 struct fuse_arg {
 169         unsigned size;
 170         void *value;
 171 };
 172
 173 /** The request output */
 174 struct fuse_out {
 175         /** Header returned from userspace */
 176         struct fuse_out_header h;
 177
 178         /*
 179          * The following bitfields are not changed during the request
 180          * processing
 181          */
 182
 183         /** Last argument is variable length (can be shorter than
 184             arg->size) */
 185         unsigned argvar:1;
 186
 187         /** Last argument is a list of pages to copy data to */
 188         unsigned argpages:1;
 189
 190         /** Zero partially or not copied pages */
 191         unsigned page_zeroing:1;
 192
 193         /** Pages may be replaced with new ones */
 194         unsigned page_replace:1;
 195
 196         /** Number or arguments */
 197         unsigned numargs;
 198
 199         /** Array of arguments */
 200         struct fuse_arg args[3];
 201 };
 202
 203 /** The request state */
 204 enum fuse_req_state {
 205         FUSE_REQ_INIT = 0,
 206         FUSE_REQ_PENDING,
 207         FUSE_REQ_READING,
 208         FUSE_REQ_SENT,
 209         FUSE_REQ_WRITING,
 210         FUSE_REQ_FINISHED
 211 };
 212
 213 /**
 214  * A request to the client
 215  */
 216 struct fuse_req {
 217         /** This can be on either pending processing or io lists in
 218             fuse_conn */
 219         struct list_head list;
 220
 221         /** Entry on the interrupts list  */
 222         struct list_head intr_entry;
 223
 224         /** refcount */
 225         atomic_t count;
 226
 227         /** Unique ID for the interrupt request */
 228         u64 intr_unique;
 229
 230         /*
 231          * The following bitfields are either set once before the
 232          * request is queued or setting/clearing them is protected by
 233          * fuse_conn->lock
 234          */
 235
 236         /** True if the request has reply */
 237         unsigned isreply:1;
 238
 239         /** Force sending of the request even if interrupted */
 240         unsigned force:1;
 241
 242         /** The request was aborted */
 243         unsigned aborted:1;
 244
 245         /** Request is sent in the background */
 246         unsigned background:1;
 247
 248         /** The request has been interrupted */
 249         unsigned interrupted:1;
 250
 251         /** Data is being copied to/from the request */
 252         unsigned locked:1;
 253
 254         /** Request is counted as "waiting" */
 255         unsigned waiting:1;
 256
 257         /** State of the request */
 258         enum fuse_req_state state;
 259
 260         /** The request input */
 261         struct fuse_in in;
 262
 263         /** The request output */
 264         struct fuse_out out;
 265
 266         /** Used to wake up the task waiting for completion of request*/
 267         wait_queue_head_t waitq;
 268
 269         /** Data for asynchronous requests */
 270         union {
 271                 struct {
 272                         union {
 273                                 struct fuse_release_in in;
 274                                 struct work_struct work;
 275                         };
 276                         struct path path;
 277                 } release;
 278                 struct fuse_init_in init_in;
 279                 struct fuse_init_out init_out;
 280                 struct cuse_init_in cuse_init_in;
 281                 struct {
 282                         struct fuse_read_in in;
 283                         u64 attr_ver;
 284                 } read;
 285                 struct {
 286                         struct fuse_write_in in;
 287                         struct fuse_write_out out;
 288                 } write;
 289                 struct fuse_notify_retrieve_in retrieve_in;
 290                 struct fuse_lk_in lk_in;
 291         } misc;
 292
 293         /** page vector */
 294         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 295
 296         /** number of pages in vector */
 297         unsigned num_pages;
 298
 299         /** offset of data on first page */
 300         unsigned page_offset;
 301
 302         /** File used in the request (or NULL) */
 303         struct fuse_file *ff;
 304
 305         /** Inode used in the request or NULL */
 306         struct inode *inode;
 307
 308         /** Link on fi->writepages */
 309         struct list_head writepages_entry;
 310
 311         /** Request completion callback */
 312         void (*end)(struct fuse_conn *, struct fuse_req *);
 313
 314         /** Request is stolen from fuse_file->reserved_req */
 315         struct file *stolen_file;
 316 };
 317
 318 /**
 319  * A Fuse connection.
 320  *
 321  * This structure is created, when the filesystem is mounted, and is
 322  * destroyed, when the client device is closed and the filesystem is
 323  * unmounted.
 324  */
 325 struct fuse_conn {
 326         /** Lock protecting accessess to  members of this structure */
 327         spinlock_t lock;
 328
 329         /** Mutex protecting against directory alias creation */
 330         struct mutex inst_mutex;
 331
 332         /** Refcount */
 333         atomic_t count;
 334
 335         /** The user id for this mount */
 336         uid_t user_id;
 337
 338         /** The group id for this mount */
 339         gid_t group_id;
 340
 341         /** The fuse mount flags for this mount */
 342         unsigned flags;
 343
 344         /** Maximum read size */
 345         unsigned max_read;
 346
 347         /** Maximum write size */
 348         unsigned max_write;
 349
 350         /** Readers of the connection are waiting on this */
 351         wait_queue_head_t waitq;
 352
 353         /** The list of pending requests */
 354         struct list_head pending;
 355
 356         /** The list of requests being processed */
 357         struct list_head processing;
 358
 359         /** The list of requests under I/O */
 360         struct list_head io;
 361
 362         /** The next unique kernel file handle */
 363         u64 khctr;
 364
 365         /** rbtree of fuse_files waiting for poll events indexed by ph */
 366         struct rb_root polled_files;
 367
 368         /** Maximum number of outstanding background requests */
 369         unsigned max_background;
 370
 371         /** Number of background requests at which congestion starts */
 372         unsigned congestion_threshold;
 373
 374         /** Number of requests currently in the background */
 375         unsigned num_background;
 376
 377         /** Number of background requests currently queued for userspace */
 378         unsigned active_background;
 379
 380         /** The list of background requests set aside for later queuing */
 381         struct list_head bg_queue;
 382
 383         /** Pending interrupts */
 384         struct list_head interrupts;
 385
 386         /** Queue of pending forgets */
 387         struct fuse_forget_link forget_list_head;
 388         struct fuse_forget_link *forget_list_tail;
 389
 390         /** Batching of FORGET requests (positive indicates FORGET batch) */
 391         int forget_batch;
 392
 393         /** Flag indicating if connection is blocked.  This will be
 394             the case before the INIT reply is received, and if there
 395             are too many outstading backgrounds requests */
 396         int blocked;
 397
 398         /** waitq for blocked connection */
 399         wait_queue_head_t blocked_waitq;
 400
 401         /** waitq for reserved requests */
 402         wait_queue_head_t reserved_req_waitq;
 403
 404         /** The next unique request id */
 405         u64 reqctr;
 406
 407         /** Connection established, cleared on umount, connection
 408             abort and device release */
 409         unsigned connected;
 410
 411         /** Connection failed (version mismatch).  Cannot race with
 412             setting other bitfields since it is only set once in INIT
 413             reply, before any other request, and never cleared */
 414         unsigned conn_error:1;
 415
 416         /** Connection successful.  Only set in INIT */
 417         unsigned conn_init:1;
 418
 419         /** Do readpages asynchronously?  Only set in INIT */
 420         unsigned async_read:1;
 421
 422         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 423         unsigned atomic_o_trunc:1;
 424
 425         /** Filesystem supports NFS exporting.  Only set in INIT */
 426         unsigned export_support:1;
 427
 428         /** Set if bdi is valid */
 429         unsigned bdi_initialized:1;
 430
 431         /*
 432          * The following bitfields are only for optimization purposes
 433          * and hence races in setting them will not cause malfunction
 434          */
 435
 436         /** Is fsync not implemented by fs? */
 437         unsigned no_fsync:1;
 438
 439         /** Is fsyncdir not implemented by fs? */
 440         unsigned no_fsyncdir:1;
 441
 442         /** Is flush not implemented by fs? */
 443         unsigned no_flush:1;
 444
 445         /** Is setxattr not implemented by fs? */
 446         unsigned no_setxattr:1;
 447
 448         /** Is getxattr not implemented by fs? */
 449         unsigned no_getxattr:1;
 450
 451         /** Is listxattr not implemented by fs? */
 452         unsigned no_listxattr:1;
 453
 454         /** Is removexattr not implemented by fs? */
 455         unsigned no_removexattr:1;
 456
 457         /** Are posix file locking primitives not implemented by fs? */
 458         unsigned no_lock:1;
 459
 460         /** Is access not implemented by fs? */
 461         unsigned no_access:1;
 462
 463         /** Is create not implemented by fs? */
 464         unsigned no_create:1;
 465
 466         /** Is interrupt not implemented by fs? */
 467         unsigned no_interrupt:1;
 468
 469         /** Is bmap not implemented by fs? */
 470         unsigned no_bmap:1;
 471
 472         /** Is poll not implemented by fs? */
 473         unsigned no_poll:1;
 474
 475         /** Do multi-page cached writes */
 476         unsigned big_writes:1;
 477
 478         /** Don't apply umask to creation modes */
 479         unsigned dont_mask:1;
 480
 481         /** Are BSD file locking primitives not implemented by fs? */
 482         unsigned no_flock:1;
 483
 484         /** Is fallocate not implemented by fs? */
 485         unsigned no_fallocate:1;
 486
 487         /** The number of requests waiting for completion */
 488         atomic_t num_waiting;
 489
 490         /** Negotiated minor version */
 491         unsigned minor;
 492
 493         /** Backing dev info */
 494         struct backing_dev_info bdi;
 495
 496         /** Entry on the fuse_conn_list */
 497         struct list_head entry;
 498
 499         /** Device ID from super block */
 500         dev_t dev;
 501
 502         /** Dentries in the control filesystem */
 503         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 504
 505         /** number of dentries used in the above array */
 506         int ctl_ndents;
 507
 508         /** O_ASYNC requests */
 509         struct fasync_struct *fasync;
 510
 511         /** Key for lock owner ID scrambling */
 512         u32 scramble_key[4];
 513
 514         /** Reserved request for the DESTROY message */
 515         struct fuse_req *destroy_req;
 516
 517         /** Version counter for attribute changes */
 518         u64 attr_version;
 519
 520         /** Called on final put */
 521         void (*release)(struct fuse_conn *);
 522
 523         /** Super block for this connection. */
 524         struct super_block *sb;
 525
 526         /** Read/write semaphore to hold when accessing sb. */
 527         struct rw_semaphore killsb;
 528 };
 529
 530 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 531 {
 532         return sb->s_fs_info;
 533 }
 534
 535 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 536 {
 537         return get_fuse_conn_super(inode->i_sb);
 538 }
 539
 540 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 541 {
 542         return container_of(inode, struct fuse_inode, inode);
 543 }
 544
 545 static inline u64 get_node_id(struct inode *inode)
 546 {
 547         return get_fuse_inode(inode)->nodeid;
 548 }
 549
 550 /** Device operations */
 551 extern const struct file_operations fuse_dev_operations;
 552
 553 extern const struct dentry_operations fuse_dentry_operations;
 554
 555 /**
 556  * Inode to nodeid comparison.
 557  */
 558 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
 559
 560 /**
 561  * Get a filled in inode
 562  */
 563 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 564                         int generation, struct fuse_attr *attr,
 565                         u64 attr_valid, u64 attr_version);
 566
 567 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 568                      struct fuse_entry_out *outarg, struct inode **inode);
 569
 570 /**
 571  * Send FORGET command
 572  */
 573 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 574                        u64 nodeid, u64 nlookup);
 575
 576 struct fuse_forget_link *fuse_alloc_forget(void);
 577
 578 /**
 579  * Initialize READ or READDIR request
 580  */
 581 void fuse_read_fill(struct fuse_req *req, struct file *file,
 582                     loff_t pos, size_t count, int opcode);
 583
 584 /**
 585  * Send OPEN or OPENDIR request
 586  */
 587 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 588
 589 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
 590 struct fuse_file *fuse_file_get(struct fuse_file *ff);
 591 void fuse_file_free(struct fuse_file *ff);
 592 void fuse_finish_open(struct inode *inode, struct file *file);
 593
 594 void fuse_sync_release(struct fuse_file *ff, int flags);
 595
 596 /**
 597  * Send RELEASE or RELEASEDIR request
 598  */
 599 void fuse_release_common(struct file *file, int opcode);
 600
 601 /**
 602  * Send FSYNC or FSYNCDIR request
 603  */
 604 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 605                       int datasync, int isdir);
 606
 607 /**
 608  * Notify poll wakeup
 609  */
 610 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
 611                             struct fuse_notify_poll_wakeup_out *outarg);
 612
 613 /**
 614  * Initialize file operations on a regular file
 615  */
 616 void fuse_init_file_inode(struct inode *inode);
 617
 618 /**
 619  * Initialize inode operations on regular files and special files
 620  */
 621 void fuse_init_common(struct inode *inode);
 622
 623 /**
 624  * Initialize inode and file operations on a directory
 625  */
 626 void fuse_init_dir(struct inode *inode);
 627
 628 /**
 629  * Initialize inode operations on a symlink
 630  */
 631 void fuse_init_symlink(struct inode *inode);
 632
 633 /**
 634  * Change attributes of an inode
 635  */
 636 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 637                             u64 attr_valid, u64 attr_version);
 638
 639 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 640                                    u64 attr_valid);
 641
 642 /**
 643  * Initialize the client device
 644  */
 645 int fuse_dev_init(void);
 646
 647 /**
 648  * Cleanup the client device
 649  */
 650 void fuse_dev_cleanup(void);
 651
 652 int fuse_ctl_init(void);
 653 void fuse_ctl_cleanup(void);
 654
 655 /**
 656  * Allocate a request
 657  */
 658 struct fuse_req *fuse_request_alloc(void);
 659
 660 struct fuse_req *fuse_request_alloc_nofs(void);
 661
 662 /**
 663  * Free a request
 664  */
 665 void fuse_request_free(struct fuse_req *req);
 666
 667 /**
 668  * Get a request, may fail with -ENOMEM
 669  */
 670 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 671
 672 /**
 673  * Gets a requests for a file operation, always succeeds
 674  */
 675 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 676
 677 /**
 678  * Decrement reference count of a request.  If count goes to zero free
 679  * the request.
 680  */
 681 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 682
 683 /**
 684  * Send a request (synchronous)
 685  */
 686 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
 687
 688 /**
 689  * Send a request in the background
 690  */
 691 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 692
 693 void fuse_request_send_background_locked(struct fuse_conn *fc,
 694                                          struct fuse_req *req);
 695
 696 /* Abort all requests */
 697 void fuse_abort_conn(struct fuse_conn *fc);
 698
 699 /**
 700  * Invalidate inode attributes
 701  */
 702 void fuse_invalidate_attr(struct inode *inode);
 703
 704 void fuse_invalidate_entry_cache(struct dentry *entry);
 705
 706 /**
 707  * Acquire reference to fuse_conn
 708  */
 709 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 710
 711 void fuse_conn_kill(struct fuse_conn *fc);
 712
 713 /**
 714  * Initialize fuse_conn
 715  */
 716 void fuse_conn_init(struct fuse_conn *fc);
 717
 718 /**
 719  * Release reference to fuse_conn
 720  */
 721 void fuse_conn_put(struct fuse_conn *fc);
 722
 723 /**
 724  * Add connection to control filesystem
 725  */
 726 int fuse_ctl_add_conn(struct fuse_conn *fc);
 727
 728 /**
 729  * Remove connection from control filesystem
 730  */
 731 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 732
 733 /**
 734  * Is file type valid?
 735  */
 736 int fuse_valid_type(int m);
 737
 738 /**
 739  * Is task allowed to perform filesystem operation?
 740  */
 741 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
 742
 743 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
 744
 745 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 746                            struct file *file, bool *refreshed);
 747
 748 void fuse_flush_writepages(struct inode *inode);
 749
 750 void fuse_set_nowrite(struct inode *inode);
 751 void fuse_release_nowrite(struct inode *inode);
 752
 753 u64 fuse_get_attr_version(struct fuse_conn *fc);
 754
 755 /**
 756  * File-system tells the kernel to invalidate cache for the given node id.
 757  */
 758 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 759                              loff_t offset, loff_t len);
 760
 761 /**
 762  * File-system tells the kernel to invalidate parent attributes and
 763  * the dentry matching parent/name.
 764  *
 765  * If the child_nodeid is non-zero and:
 766  *    - matches the inode number for the dentry matching parent/name,
 767  *    - is not a mount point
 768  *    - is a file or oan empty directory
 769  * then the dentry is unhashed (d_delete()).
 770  */
 771 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
 772                              u64 child_nodeid, struct qstr *name);
 773
 774 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 775                  bool isdir);
 776 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 777                        size_t count, loff_t *ppos, int write);
 778 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
 779                    unsigned int flags);
 780 long fuse_ioctl_common(struct file *file, unsigned int cmd,
 781                        unsigned long arg, unsigned int flags);
 782 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 783 int fuse_dev_release(struct inode *inode, struct file *file);
 784
 785 void fuse_write_update_size(struct inode *inode, loff_t pos);
 786
 787 #endif /* _FS_FUSE_I_H */