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