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 #ifndef pr_fmt
  13 # define pr_fmt(fmt) "fuse: " fmt
  14 #endif
  15
  16 #include <linux/fuse.h>
  17 #include <linux/fs.h>
  18 #include <linux/mount.h>
  19 #include <linux/wait.h>
  20 #include <linux/list.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/mm.h>
  23 #include <linux/backing-dev.h>
  24 #include <linux/mutex.h>
  25 #include <linux/rwsem.h>
  26 #include <linux/rbtree.h>
  27 #include <linux/poll.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/kref.h>
  30 #include <linux/xattr.h>
  31 #include <linux/pid_namespace.h>
  32 #include <linux/refcount.h>
  33 #include <linux/user_namespace.h>
  34
  35 /** Default max number of pages that can be used in a single read request */
  36 #define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
  37
  38 /** Maximum of max_pages received in init_out */
  39 #define FUSE_MAX_MAX_PAGES 256
  40
  41 /** Bias for fi->writectr, meaning new writepages must not be sent */
  42 #define FUSE_NOWRITE INT_MIN
  43
  44 /** It could be as large as PATH_MAX, but would that have any uses? */
  45 #define FUSE_NAME_MAX 1024
  46
  47 /** Number of dentries for each connection in the control filesystem */
  48 #define FUSE_CTL_NUM_DENTRIES 5
  49
  50 /** List of active connections */
  51 extern struct list_head fuse_conn_list;
  52
  53 /** Global mutex protecting fuse_conn_list and the control filesystem */
  54 extern struct mutex fuse_mutex;
  55
  56 /** Module parameters */
  57 extern unsigned max_user_bgreq;
  58 extern unsigned max_user_congthresh;
  59
  60 /* One forget request */
  61 struct fuse_forget_link {
  62         struct fuse_forget_one forget_one;
  63         struct fuse_forget_link *next;
  64 };
  65
  66 /* Submount lookup tracking */
  67 struct fuse_submount_lookup {
  68         /** Refcount */
  69         refcount_t count;
  70
  71         /** Unique ID, which identifies the inode between userspace
  72          * and kernel */
  73         u64 nodeid;
  74
  75         /** The request used for sending the FORGET message */
  76         struct fuse_forget_link *forget;
  77 };
  78
  79 /** FUSE inode */
  80 struct fuse_inode {
  81         /** Inode data */
  82         struct inode inode;
  83
  84         /** Unique ID, which identifies the inode between userspace
  85          * and kernel */
  86         u64 nodeid;
  87
  88         /** Number of lookups on this inode */
  89         u64 nlookup;
  90
  91         /** The request used for sending the FORGET message */
  92         struct fuse_forget_link *forget;
  93
  94         /** Time in jiffies until the file attributes are valid */
  95         u64 i_time;
  96
  97         /* Which attributes are invalid */
  98         u32 inval_mask;
  99
 100         /** The sticky bit in inode->i_mode may have been removed, so
 101             preserve the original mode */
 102         umode_t orig_i_mode;
 103
 104         /* Cache birthtime */
 105         struct timespec64 i_btime;
 106
 107         /** 64 bit inode number */
 108         u64 orig_ino;
 109
 110         /** Version of last attribute change */
 111         u64 attr_version;
 112
 113         union {
 114                 /* Write related fields (regular file only) */
 115                 struct {
 116                         /* Files usable in writepage.  Protected by fi->lock */
 117                         struct list_head write_files;
 118
 119                         /* Writepages pending on truncate or fsync */
 120                         struct list_head queued_writes;
 121
 122                         /* Number of sent writes, a negative bias
 123                          * (FUSE_NOWRITE) means more writes are blocked */
 124                         int writectr;
 125
 126                         /* Waitq for writepage completion */
 127                         wait_queue_head_t page_waitq;
 128
 129                         /* List of writepage requestst (pending or sent) */
 130                         struct rb_root writepages;
 131                 };
 132
 133                 /* readdir cache (directory only) */
 134                 struct {
 135                         /* true if fully cached */
 136                         bool cached;
 137
 138                         /* size of cache */
 139                         loff_t size;
 140
 141                         /* position at end of cache (position of next entry) */
 142                         loff_t pos;
 143
 144                         /* version of the cache */
 145                         u64 version;
 146
 147                         /* modification time of directory when cache was
 148                          * started */
 149                         struct timespec64 mtime;
 150
 151                         /* iversion of directory when cache was started */
 152                         u64 iversion;
 153
 154                         /* protects above fields */
 155                         spinlock_t lock;
 156                 } rdc;
 157         };
 158
 159         /** Miscellaneous bits describing inode state */
 160         unsigned long state;
 161
 162         /** Lock for serializing lookup and readdir for back compatibility*/
 163         struct mutex mutex;
 164
 165         /** Lock to protect write related fields */
 166         spinlock_t lock;
 167
 168 #ifdef CONFIG_FUSE_DAX
 169         /*
 170          * Dax specific inode data
 171          */
 172         struct fuse_inode_dax *dax;
 173 #endif
 174         /** Submount specific lookup tracking */
 175         struct fuse_submount_lookup *submount_lookup;
 176 };
 177
 178 /** FUSE inode state bits */
 179 enum {
 180         /** Advise readdirplus  */
 181         FUSE_I_ADVISE_RDPLUS,
 182         /** Initialized with readdirplus */
 183         FUSE_I_INIT_RDPLUS,
 184         /** An operation changing file size is in progress  */
 185         FUSE_I_SIZE_UNSTABLE,
 186         /* Bad inode */
 187         FUSE_I_BAD,
 188         /* Has btime */
 189         FUSE_I_BTIME,
 190 };
 191
 192 struct fuse_conn;
 193 struct fuse_mount;
 194 struct fuse_release_args;
 195
 196 /** FUSE specific file data */
 197 struct fuse_file {
 198         /** Fuse connection for this file */
 199         struct fuse_mount *fm;
 200
 201         /* Argument space reserved for release */
 202         struct fuse_release_args *release_args;
 203
 204         /** Kernel file handle guaranteed to be unique */
 205         u64 kh;
 206
 207         /** File handle used by userspace */
 208         u64 fh;
 209
 210         /** Node id of this file */
 211         u64 nodeid;
 212
 213         /** Refcount */
 214         refcount_t count;
 215
 216         /** FOPEN_* flags returned by open */
 217         u32 open_flags;
 218
 219         /** Entry on inode's write_files list */
 220         struct list_head write_entry;
 221
 222         /* Readdir related */
 223         struct {
 224                 /*
 225                  * Protects below fields against (crazy) parallel readdir on
 226                  * same open file.  Uncontended in the normal case.
 227                  */
 228                 struct mutex lock;
 229
 230                 /* Dir stream position */
 231                 loff_t pos;
 232
 233                 /* Offset in cache */
 234                 loff_t cache_off;
 235
 236                 /* Version of cache we are reading */
 237                 u64 version;
 238
 239         } readdir;
 240
 241         /** RB node to be linked on fuse_conn->polled_files */
 242         struct rb_node polled_node;
 243
 244         /** Wait queue head for poll */
 245         wait_queue_head_t poll_wait;
 246
 247         /** Has flock been performed on this file? */
 248         bool flock:1;
 249 };
 250
 251 /** One input argument of a request */
 252 struct fuse_in_arg {
 253         unsigned size;
 254         const void *value;
 255 };
 256
 257 /** One output argument of a request */
 258 struct fuse_arg {
 259         unsigned size;
 260         void *value;
 261 };
 262
 263 /** FUSE page descriptor */
 264 struct fuse_page_desc {
 265         unsigned int length;
 266         unsigned int offset;
 267 };
 268
 269 struct fuse_args {
 270         uint64_t nodeid;
 271         uint32_t opcode;
 272         uint8_t in_numargs;
 273         uint8_t out_numargs;
 274         uint8_t ext_idx;
 275         bool force:1;
 276         bool noreply:1;
 277         bool nocreds:1;
 278         bool in_pages:1;
 279         bool out_pages:1;
 280         bool user_pages:1;
 281         bool out_argvar:1;
 282         bool page_zeroing:1;
 283         bool page_replace:1;
 284         bool may_block:1;
 285         bool is_ext:1;
 286         struct fuse_in_arg in_args[3];
 287         struct fuse_arg out_args[2];
 288         void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error);
 289 };
 290
 291 struct fuse_args_pages {
 292         struct fuse_args args;
 293         struct page **pages;
 294         struct fuse_page_desc *descs;
 295         unsigned int num_pages;
 296 };
 297
 298 #define FUSE_ARGS(args) struct fuse_args args = {}
 299
 300 /** The request IO state (for asynchronous processing) */
 301 struct fuse_io_priv {
 302         struct kref refcnt;
 303         int async;
 304         spinlock_t lock;
 305         unsigned reqs;
 306         ssize_t bytes;
 307         size_t size;
 308         __u64 offset;
 309         bool write;
 310         bool should_dirty;
 311         int err;
 312         struct kiocb *iocb;
 313         struct completion *done;
 314         bool blocking;
 315 };
 316
 317 #define FUSE_IO_PRIV_SYNC(i) \
 318 {                                       \
 319         .refcnt = KREF_INIT(1),         \
 320         .async = 0,                     \
 321         .iocb = i,                      \
 322 }
 323
 324 /**
 325  * Request flags
 326  *
 327  * FR_ISREPLY:          set if the request has reply
 328  * FR_FORCE:            force sending of the request even if interrupted
 329  * FR_BACKGROUND:       request is sent in the background
 330  * FR_WAITING:          request is counted as "waiting"
 331  * FR_ABORTED:          the request was aborted
 332  * FR_INTERRUPTED:      the request has been interrupted
 333  * FR_LOCKED:           data is being copied to/from the request
 334  * FR_PENDING:          request is not yet in userspace
 335  * FR_SENT:             request is in userspace, waiting for an answer
 336  * FR_FINISHED:         request is finished
 337  * FR_PRIVATE:          request is on private list
 338  * FR_ASYNC:            request is asynchronous
 339  */
 340 enum fuse_req_flag {
 341         FR_ISREPLY,
 342         FR_FORCE,
 343         FR_BACKGROUND,
 344         FR_WAITING,
 345         FR_ABORTED,
 346         FR_INTERRUPTED,
 347         FR_LOCKED,
 348         FR_PENDING,
 349         FR_SENT,
 350         FR_FINISHED,
 351         FR_PRIVATE,
 352         FR_ASYNC,
 353 };
 354
 355 /**
 356  * A request to the client
 357  *
 358  * .waitq.lock protects the following fields:
 359  *   - FR_ABORTED
 360  *   - FR_LOCKED (may also be modified under fc->lock, tested under both)
 361  */
 362 struct fuse_req {
 363         /** This can be on either pending processing or io lists in
 364             fuse_conn */
 365         struct list_head list;
 366
 367         /** Entry on the interrupts list  */
 368         struct list_head intr_entry;
 369
 370         /* Input/output arguments */
 371         struct fuse_args *args;
 372
 373         /** refcount */
 374         refcount_t count;
 375
 376         /* Request flags, updated with test/set/clear_bit() */
 377         unsigned long flags;
 378
 379         /* The request input header */
 380         struct {
 381                 struct fuse_in_header h;
 382         } in;
 383
 384         /* The request output header */
 385         struct {
 386                 struct fuse_out_header h;
 387         } out;
 388
 389         /** Used to wake up the task waiting for completion of request*/
 390         wait_queue_head_t waitq;
 391
 392 #if IS_ENABLED(CONFIG_VIRTIO_FS)
 393         /** virtio-fs's physically contiguous buffer for in and out args */
 394         void *argbuf;
 395 #endif
 396
 397         /** fuse_mount this request belongs to */
 398         struct fuse_mount *fm;
 399 };
 400
 401 struct fuse_iqueue;
 402
 403 /**
 404  * Input queue callbacks
 405  *
 406  * Input queue signalling is device-specific.  For example, the /dev/fuse file
 407  * uses fiq->waitq and fasync to wake processes that are waiting on queue
 408  * readiness.  These callbacks allow other device types to respond to input
 409  * queue activity.
 410  */
 411 struct fuse_iqueue_ops {
 412         /**
 413          * Signal that a forget has been queued
 414          */
 415         void (*wake_forget_and_unlock)(struct fuse_iqueue *fiq)
 416                 __releases(fiq->lock);
 417
 418         /**
 419          * Signal that an INTERRUPT request has been queued
 420          */
 421         void (*wake_interrupt_and_unlock)(struct fuse_iqueue *fiq)
 422                 __releases(fiq->lock);
 423
 424         /**
 425          * Signal that a request has been queued
 426          */
 427         void (*wake_pending_and_unlock)(struct fuse_iqueue *fiq)
 428                 __releases(fiq->lock);
 429
 430         /**
 431          * Clean up when fuse_iqueue is destroyed
 432          */
 433         void (*release)(struct fuse_iqueue *fiq);
 434 };
 435
 436 /** /dev/fuse input queue operations */
 437 extern const struct fuse_iqueue_ops fuse_dev_fiq_ops;
 438
 439 struct fuse_iqueue {
 440         /** Connection established */
 441         unsigned connected;
 442
 443         /** Lock protecting accesses to members of this structure */
 444         spinlock_t lock;
 445
 446         /** Readers of the connection are waiting on this */
 447         wait_queue_head_t waitq;
 448
 449         /** The next unique request id */
 450         u64 reqctr;
 451
 452         /** The list of pending requests */
 453         struct list_head pending;
 454
 455         /** Pending interrupts */
 456         struct list_head interrupts;
 457
 458         /** Queue of pending forgets */
 459         struct fuse_forget_link forget_list_head;
 460         struct fuse_forget_link *forget_list_tail;
 461
 462         /** Batching of FORGET requests (positive indicates FORGET batch) */
 463         int forget_batch;
 464
 465         /** O_ASYNC requests */
 466         struct fasync_struct *fasync;
 467
 468         /** Device-specific callbacks */
 469         const struct fuse_iqueue_ops *ops;
 470
 471         /** Device-specific state */
 472         void *priv;
 473 };
 474
 475 #define FUSE_PQ_HASH_BITS 8
 476 #define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)
 477
 478 struct fuse_pqueue {
 479         /** Connection established */
 480         unsigned connected;
 481
 482         /** Lock protecting accessess to  members of this structure */
 483         spinlock_t lock;
 484
 485         /** Hash table of requests being processed */
 486         struct list_head *processing;
 487
 488         /** The list of requests under I/O */
 489         struct list_head io;
 490 };
 491
 492 /**
 493  * Fuse device instance
 494  */
 495 struct fuse_dev {
 496         /** Fuse connection for this device */
 497         struct fuse_conn *fc;
 498
 499         /** Processing queue */
 500         struct fuse_pqueue pq;
 501
 502         /** list entry on fc->devices */
 503         struct list_head entry;
 504 };
 505
 506 enum fuse_dax_mode {
 507         FUSE_DAX_INODE_DEFAULT, /* default */
 508         FUSE_DAX_ALWAYS,        /* "-o dax=always" */
 509         FUSE_DAX_NEVER,         /* "-o dax=never" */
 510         FUSE_DAX_INODE_USER,    /* "-o dax=inode" */
 511 };
 512
 513 static inline bool fuse_is_inode_dax_mode(enum fuse_dax_mode mode)
 514 {
 515         return mode == FUSE_DAX_INODE_DEFAULT || mode == FUSE_DAX_INODE_USER;
 516 }
 517
 518 struct fuse_fs_context {
 519         int fd;
 520         struct file *file;
 521         unsigned int rootmode;
 522         kuid_t user_id;
 523         kgid_t group_id;
 524         bool is_bdev:1;
 525         bool fd_present:1;
 526         bool rootmode_present:1;
 527         bool user_id_present:1;
 528         bool group_id_present:1;
 529         bool default_permissions:1;
 530         bool allow_other:1;
 531         bool destroy:1;
 532         bool no_control:1;
 533         bool no_force_umount:1;
 534         bool legacy_opts_show:1;
 535         enum fuse_dax_mode dax_mode;
 536         unsigned int max_read;
 537         unsigned int blksize;
 538         const char *subtype;
 539
 540         /* DAX device, may be NULL */
 541         struct dax_device *dax_dev;
 542
 543         /* fuse_dev pointer to fill in, should contain NULL on entry */
 544         void **fudptr;
 545 };
 546
 547 struct fuse_sync_bucket {
 548         /* count is a possible scalability bottleneck */
 549         atomic_t count;
 550         wait_queue_head_t waitq;
 551         struct rcu_head rcu;
 552 };
 553
 554 /**
 555  * A Fuse connection.
 556  *
 557  * This structure is created, when the root filesystem is mounted, and
 558  * is destroyed, when the client device is closed and the last
 559  * fuse_mount is destroyed.
 560  */
 561 struct fuse_conn {
 562         /** Lock protecting accessess to  members of this structure */
 563         spinlock_t lock;
 564
 565         /** Refcount */
 566         refcount_t count;
 567
 568         /** Number of fuse_dev's */
 569         atomic_t dev_count;
 570
 571         struct rcu_head rcu;
 572
 573         /** The user id for this mount */
 574         kuid_t user_id;
 575
 576         /** The group id for this mount */
 577         kgid_t group_id;
 578
 579         /** The pid namespace for this mount */
 580         struct pid_namespace *pid_ns;
 581
 582         /** The user namespace for this mount */
 583         struct user_namespace *user_ns;
 584
 585         /** Maximum read size */
 586         unsigned max_read;
 587
 588         /** Maximum write size */
 589         unsigned max_write;
 590
 591         /** Maximum number of pages that can be used in a single request */
 592         unsigned int max_pages;
 593
 594         /** Constrain ->max_pages to this value during feature negotiation */
 595         unsigned int max_pages_limit;
 596
 597         /** Input queue */
 598         struct fuse_iqueue iq;
 599
 600         /** The next unique kernel file handle */
 601         atomic64_t khctr;
 602
 603         /** rbtree of fuse_files waiting for poll events indexed by ph */
 604         struct rb_root polled_files;
 605
 606         /** Maximum number of outstanding background requests */
 607         unsigned max_background;
 608
 609         /** Number of background requests at which congestion starts */
 610         unsigned congestion_threshold;
 611
 612         /** Number of requests currently in the background */
 613         unsigned num_background;
 614
 615         /** Number of background requests currently queued for userspace */
 616         unsigned active_background;
 617
 618         /** The list of background requests set aside for later queuing */
 619         struct list_head bg_queue;
 620
 621         /** Protects: max_background, congestion_threshold, num_background,
 622          * active_background, bg_queue, blocked */
 623         spinlock_t bg_lock;
 624
 625         /** Flag indicating that INIT reply has been received. Allocating
 626          * any fuse request will be suspended until the flag is set */
 627         int initialized;
 628
 629         /** Flag indicating if connection is blocked.  This will be
 630             the case before the INIT reply is received, and if there
 631             are too many outstading backgrounds requests */
 632         int blocked;
 633
 634         /** waitq for blocked connection */
 635         wait_queue_head_t blocked_waitq;
 636
 637         /** Connection established, cleared on umount, connection
 638             abort and device release */
 639         unsigned connected;
 640
 641         /** Connection aborted via sysfs */
 642         bool aborted;
 643
 644         /** Connection failed (version mismatch).  Cannot race with
 645             setting other bitfields since it is only set once in INIT
 646             reply, before any other request, and never cleared */
 647         unsigned conn_error:1;
 648
 649         /** Connection successful.  Only set in INIT */
 650         unsigned conn_init:1;
 651
 652         /** Do readahead asynchronously?  Only set in INIT */
 653         unsigned async_read:1;
 654
 655         /** Return an unique read error after abort.  Only set in INIT */
 656         unsigned abort_err:1;
 657
 658         /** Do not send separate SETATTR request before open(O_TRUNC)  */
 659         unsigned atomic_o_trunc:1;
 660
 661         /** Filesystem supports NFS exporting.  Only set in INIT */
 662         unsigned export_support:1;
 663
 664         /** write-back cache policy (default is write-through) */
 665         unsigned writeback_cache:1;
 666
 667         /** allow parallel lookups and readdir (default is serialized) */
 668         unsigned parallel_dirops:1;
 669
 670         /** handle fs handles killing suid/sgid/cap on write/chown/trunc */
 671         unsigned handle_killpriv:1;
 672
 673         /** cache READLINK responses in page cache */
 674         unsigned cache_symlinks:1;
 675
 676         /* show legacy mount options */
 677         unsigned int legacy_opts_show:1;
 678
 679         /*
 680          * fs kills suid/sgid/cap on write/chown/trunc. suid is killed on
 681          * write/trunc only if caller did not have CAP_FSETID.  sgid is killed
 682          * on write/truncate only if caller did not have CAP_FSETID as well as
 683          * file has group execute permission.
 684          */
 685         unsigned handle_killpriv_v2:1;
 686
 687         /*
 688          * The following bitfields are only for optimization purposes
 689          * and hence races in setting them will not cause malfunction
 690          */
 691
 692         /** Is open/release not implemented by fs? */
 693         unsigned no_open:1;
 694
 695         /** Is opendir/releasedir not implemented by fs? */
 696         unsigned no_opendir:1;
 697
 698         /** Is fsync not implemented by fs? */
 699         unsigned no_fsync:1;
 700
 701         /** Is fsyncdir not implemented by fs? */
 702         unsigned no_fsyncdir:1;
 703
 704         /** Is flush not implemented by fs? */
 705         unsigned no_flush:1;
 706
 707         /** Is setxattr not implemented by fs? */
 708         unsigned no_setxattr:1;
 709
 710         /** Does file server support extended setxattr */
 711         unsigned setxattr_ext:1;
 712
 713         /** Is getxattr not implemented by fs? */
 714         unsigned no_getxattr:1;
 715
 716         /** Is listxattr not implemented by fs? */
 717         unsigned no_listxattr:1;
 718
 719         /** Is removexattr not implemented by fs? */
 720         unsigned no_removexattr:1;
 721
 722         /** Are posix file locking primitives not implemented by fs? */
 723         unsigned no_lock:1;
 724
 725         /** Is access not implemented by fs? */
 726         unsigned no_access:1;
 727
 728         /** Is create not implemented by fs? */
 729         unsigned no_create:1;
 730
 731         /** Is interrupt not implemented by fs? */
 732         unsigned no_interrupt:1;
 733
 734         /** Is bmap not implemented by fs? */
 735         unsigned no_bmap:1;
 736
 737         /** Is poll not implemented by fs? */
 738         unsigned no_poll:1;
 739
 740         /** Do multi-page cached writes */
 741         unsigned big_writes:1;
 742
 743         /** Don't apply umask to creation modes */
 744         unsigned dont_mask:1;
 745
 746         /** Are BSD file locking primitives not implemented by fs? */
 747         unsigned no_flock:1;
 748
 749         /** Is fallocate not implemented by fs? */
 750         unsigned no_fallocate:1;
 751
 752         /** Is rename with flags implemented by fs? */
 753         unsigned no_rename2:1;
 754
 755         /** Use enhanced/automatic page cache invalidation. */
 756         unsigned auto_inval_data:1;
 757
 758         /** Filesystem is fully responsible for page cache invalidation. */
 759         unsigned explicit_inval_data:1;
 760
 761         /** Does the filesystem support readdirplus? */
 762         unsigned do_readdirplus:1;
 763
 764         /** Does the filesystem want adaptive readdirplus? */
 765         unsigned readdirplus_auto:1;
 766
 767         /** Does the filesystem support asynchronous direct-IO submission? */
 768         unsigned async_dio:1;
 769
 770         /** Is lseek not implemented by fs? */
 771         unsigned no_lseek:1;
 772
 773         /** Does the filesystem support posix acls? */
 774         unsigned posix_acl:1;
 775
 776         /** Check permissions based on the file mode or not? */
 777         unsigned default_permissions:1;
 778
 779         /** Allow other than the mounter user to access the filesystem ? */
 780         unsigned allow_other:1;
 781
 782         /** Does the filesystem support copy_file_range? */
 783         unsigned no_copy_file_range:1;
 784
 785         /* Send DESTROY request */
 786         unsigned int destroy:1;
 787
 788         /* Delete dentries that have gone stale */
 789         unsigned int delete_stale:1;
 790
 791         /** Do not create entry in fusectl fs */
 792         unsigned int no_control:1;
 793
 794         /** Do not allow MNT_FORCE umount */
 795         unsigned int no_force_umount:1;
 796
 797         /* Auto-mount submounts announced by the server */
 798         unsigned int auto_submounts:1;
 799
 800         /* Propagate syncfs() to server */
 801         unsigned int sync_fs:1;
 802
 803         /* Initialize security xattrs when creating a new inode */
 804         unsigned int init_security:1;
 805
 806         /* Add supplementary group info when creating a new inode */
 807         unsigned int create_supp_group:1;
 808
 809         /* Does the filesystem support per inode DAX? */
 810         unsigned int inode_dax:1;
 811
 812         /* Is tmpfile not implemented by fs? */
 813         unsigned int no_tmpfile:1;
 814
 815         /* Relax restrictions to allow shared mmap in FOPEN_DIRECT_IO mode */
 816         unsigned int direct_io_allow_mmap:1;
 817
 818         /* Is statx not implemented by fs? */
 819         unsigned int no_statx:1;
 820
 821         /** The number of requests waiting for completion */
 822         atomic_t num_waiting;
 823
 824         /** Negotiated minor version */
 825         unsigned minor;
 826
 827         /** Entry on the fuse_mount_list */
 828         struct list_head entry;
 829
 830         /** Device ID from the root super block */
 831         dev_t dev;
 832
 833         /** Dentries in the control filesystem */
 834         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 835
 836         /** number of dentries used in the above array */
 837         int ctl_ndents;
 838
 839         /** Key for lock owner ID scrambling */
 840         u32 scramble_key[4];
 841
 842         /** Version counter for attribute changes */
 843         atomic64_t attr_version;
 844
 845         /** Called on final put */
 846         void (*release)(struct fuse_conn *);
 847
 848         /**
 849          * Read/write semaphore to hold when accessing the sb of any
 850          * fuse_mount belonging to this connection
 851          */
 852         struct rw_semaphore killsb;
 853
 854         /** List of device instances belonging to this connection */
 855         struct list_head devices;
 856
 857 #ifdef CONFIG_FUSE_DAX
 858         /* Dax mode */
 859         enum fuse_dax_mode dax_mode;
 860
 861         /* Dax specific conn data, non-NULL if DAX is enabled */
 862         struct fuse_conn_dax *dax;
 863 #endif
 864
 865         /** List of filesystems using this connection */
 866         struct list_head mounts;
 867
 868         /* New writepages go into this bucket */
 869         struct fuse_sync_bucket __rcu *curr_bucket;
 870 };
 871
 872 /*
 873  * Represents a mounted filesystem, potentially a submount.
 874  *
 875  * This object allows sharing a fuse_conn between separate mounts to
 876  * allow submounts with dedicated superblocks and thus separate device
 877  * IDs.
 878  */
 879 struct fuse_mount {
 880         /* Underlying (potentially shared) connection to the FUSE server */
 881         struct fuse_conn *fc;
 882
 883         /*
 884          * Super block for this connection (fc->killsb must be held when
 885          * accessing this).
 886          */
 887         struct super_block *sb;
 888
 889         /* Entry on fc->mounts */
 890         struct list_head fc_entry;
 891 };
 892
 893 static inline struct fuse_mount *get_fuse_mount_super(struct super_block *sb)
 894 {
 895         return sb->s_fs_info;
 896 }
 897
 898 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 899 {
 900         return get_fuse_mount_super(sb)->fc;
 901 }
 902
 903 static inline struct fuse_mount *get_fuse_mount(struct inode *inode)
 904 {
 905         return get_fuse_mount_super(inode->i_sb);
 906 }
 907
 908 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 909 {
 910         return get_fuse_mount_super(inode->i_sb)->fc;
 911 }
 912
 913 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 914 {
 915         return container_of(inode, struct fuse_inode, inode);
 916 }
 917
 918 static inline u64 get_node_id(struct inode *inode)
 919 {
 920         return get_fuse_inode(inode)->nodeid;
 921 }
 922
 923 static inline int invalid_nodeid(u64 nodeid)
 924 {
 925         return !nodeid || nodeid == FUSE_ROOT_ID;
 926 }
 927
 928 static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
 929 {
 930         return atomic64_read(&fc->attr_version);
 931 }
 932
 933 static inline bool fuse_stale_inode(const struct inode *inode, int generation,
 934                                     struct fuse_attr *attr)
 935 {
 936         return inode->i_generation != generation ||
 937                 inode_wrong_type(inode, attr->mode);
 938 }
 939
 940 static inline void fuse_make_bad(struct inode *inode)
 941 {
 942         remove_inode_hash(inode);
 943         set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
 944 }
 945
 946 static inline bool fuse_is_bad(struct inode *inode)
 947 {
 948         return unlikely(test_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state));
 949 }
 950
 951 static inline struct page **fuse_pages_alloc(unsigned int npages, gfp_t flags,
 952                                              struct fuse_page_desc **desc)
 953 {
 954         struct page **pages;
 955
 956         pages = kzalloc(npages * (sizeof(struct page *) +
 957                                   sizeof(struct fuse_page_desc)), flags);
 958         *desc = (void *) (pages + npages);
 959
 960         return pages;
 961 }
 962
 963 static inline void fuse_page_descs_length_init(struct fuse_page_desc *descs,
 964                                                unsigned int index,
 965                                                unsigned int nr_pages)
 966 {
 967         int i;
 968
 969         for (i = index; i < index + nr_pages; i++)
 970                 descs[i].length = PAGE_SIZE - descs[i].offset;
 971 }
 972
 973 static inline void fuse_sync_bucket_dec(struct fuse_sync_bucket *bucket)
 974 {
 975         /* Need RCU protection to prevent use after free after the decrement */
 976         rcu_read_lock();
 977         if (atomic_dec_and_test(&bucket->count))
 978                 wake_up(&bucket->waitq);
 979         rcu_read_unlock();
 980 }
 981
 982 /** Device operations */
 983 extern const struct file_operations fuse_dev_operations;
 984
 985 extern const struct dentry_operations fuse_dentry_operations;
 986 extern const struct dentry_operations fuse_root_dentry_operations;
 987
 988 /**
 989  * Get a filled in inode
 990  */
 991 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 992                         int generation, struct fuse_attr *attr,
 993                         u64 attr_valid, u64 attr_version);
 994
 995 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
 996                      struct fuse_entry_out *outarg, struct inode **inode);
 997
 998 /**
 999  * Send FORGET command
1000  */
1001 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
1002                        u64 nodeid, u64 nlookup);
1003
1004 struct fuse_forget_link *fuse_alloc_forget(void);
1005
1006 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1007                                              unsigned int max,
1008                                              unsigned int *countp);
1009
1010 /*
1011  * Initialize READ or READDIR request
1012  */
1013 struct fuse_io_args {
1014         union {
1015                 struct {
1016                         struct fuse_read_in in;
1017                         u64 attr_ver;
1018                 } read;
1019                 struct {
1020                         struct fuse_write_in in;
1021                         struct fuse_write_out out;
1022                         bool page_locked;
1023                 } write;
1024         };
1025         struct fuse_args_pages ap;
1026         struct fuse_io_priv *io;
1027         struct fuse_file *ff;
1028 };
1029
1030 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
1031                          size_t count, int opcode);
1032
1033
1034 /**
1035  * Send OPEN or OPENDIR request
1036  */
1037 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
1038
1039 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm);
1040 void fuse_file_free(struct fuse_file *ff);
1041 void fuse_finish_open(struct inode *inode, struct file *file);
1042
1043 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
1044                        unsigned int flags);
1045
1046 /**
1047  * Send RELEASE or RELEASEDIR request
1048  */
1049 void fuse_release_common(struct file *file, bool isdir);
1050
1051 /**
1052  * Send FSYNC or FSYNCDIR request
1053  */
1054 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
1055                       int datasync, int opcode);
1056
1057 /**
1058  * Notify poll wakeup
1059  */
1060 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
1061                             struct fuse_notify_poll_wakeup_out *outarg);
1062
1063 /**
1064  * Initialize file operations on a regular file
1065  */
1066 void fuse_init_file_inode(struct inode *inode, unsigned int flags);
1067
1068 /**
1069  * Initialize inode operations on regular files and special files
1070  */
1071 void fuse_init_common(struct inode *inode);
1072
1073 /**
1074  * Initialize inode and file operations on a directory
1075  */
1076 void fuse_init_dir(struct inode *inode);
1077
1078 /**
1079  * Initialize inode operations on a symlink
1080  */
1081 void fuse_init_symlink(struct inode *inode);
1082
1083 /**
1084  * Change attributes of an inode
1085  */
1086 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
1087                             struct fuse_statx *sx,
1088                             u64 attr_valid, u64 attr_version);
1089
1090 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
1091                                    struct fuse_statx *sx,
1092                                    u64 attr_valid, u32 cache_mask);
1093
1094 u32 fuse_get_cache_mask(struct inode *inode);
1095
1096 /**
1097  * Initialize the client device
1098  */
1099 int fuse_dev_init(void);
1100
1101 /**
1102  * Cleanup the client device
1103  */
1104 void fuse_dev_cleanup(void);
1105
1106 int fuse_ctl_init(void);
1107 void __exit fuse_ctl_cleanup(void);
1108
1109 /**
1110  * Simple request sending that does request allocation and freeing
1111  */
1112 ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args);
1113 int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
1114                            gfp_t gfp_flags);
1115
1116 /**
1117  * End a finished request
1118  */
1119 void fuse_request_end(struct fuse_req *req);
1120
1121 /* Abort all requests */
1122 void fuse_abort_conn(struct fuse_conn *fc);
1123 void fuse_wait_aborted(struct fuse_conn *fc);
1124
1125 /**
1126  * Invalidate inode attributes
1127  */
1128
1129 /* Attributes possibly changed on data modification */
1130 #define FUSE_STATX_MODIFY       (STATX_MTIME | STATX_CTIME | STATX_BLOCKS)
1131
1132 /* Attributes possibly changed on data and/or size modification */
1133 #define FUSE_STATX_MODSIZE      (FUSE_STATX_MODIFY | STATX_SIZE)
1134
1135 void fuse_invalidate_attr(struct inode *inode);
1136 void fuse_invalidate_attr_mask(struct inode *inode, u32 mask);
1137
1138 void fuse_invalidate_entry_cache(struct dentry *entry);
1139
1140 void fuse_invalidate_atime(struct inode *inode);
1141
1142 u64 fuse_time_to_jiffies(u64 sec, u32 nsec);
1143 #define ATTR_TIMEOUT(o) \
1144         fuse_time_to_jiffies((o)->attr_valid, (o)->attr_valid_nsec)
1145
1146 void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);
1147
1148 /**
1149  * Acquire reference to fuse_conn
1150  */
1151 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
1152
1153 /**
1154  * Initialize fuse_conn
1155  */
1156 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
1157                     struct user_namespace *user_ns,
1158                     const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);
1159
1160 /**
1161  * Release reference to fuse_conn
1162  */
1163 void fuse_conn_put(struct fuse_conn *fc);
1164
1165 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
1166 struct fuse_dev *fuse_dev_alloc(void);
1167 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
1168 void fuse_dev_free(struct fuse_dev *fud);
1169 void fuse_send_init(struct fuse_mount *fm);
1170
1171 /**
1172  * Fill in superblock and initialize fuse connection
1173  * @sb: partially-initialized superblock to fill in
1174  * @ctx: mount context
1175  */
1176 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);
1177
1178 /*
1179  * Remove the mount from the connection
1180  *
1181  * Returns whether this was the last mount
1182  */
1183 bool fuse_mount_remove(struct fuse_mount *fm);
1184
1185 /*
1186  * Setup context ops for submounts
1187  */
1188 int fuse_init_fs_context_submount(struct fs_context *fsc);
1189
1190 /*
1191  * Shut down the connection (possibly sending DESTROY request).
1192  */
1193 void fuse_conn_destroy(struct fuse_mount *fm);
1194
1195 /* Drop the connection and free the fuse mount */
1196 void fuse_mount_destroy(struct fuse_mount *fm);
1197
1198 /**
1199  * Add connection to control filesystem
1200  */
1201 int fuse_ctl_add_conn(struct fuse_conn *fc);
1202
1203 /**
1204  * Remove connection from control filesystem
1205  */
1206 void fuse_ctl_remove_conn(struct fuse_conn *fc);
1207
1208 /**
1209  * Is file type valid?
1210  */
1211 int fuse_valid_type(int m);
1212
1213 bool fuse_invalid_attr(struct fuse_attr *attr);
1214
1215 /**
1216  * Is current process allowed to perform filesystem operation?
1217  */
1218 bool fuse_allow_current_process(struct fuse_conn *fc);
1219
1220 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
1221
1222 void fuse_flush_time_update(struct inode *inode);
1223 void fuse_update_ctime(struct inode *inode);
1224
1225 int fuse_update_attributes(struct inode *inode, struct file *file, u32 mask);
1226
1227 void fuse_flush_writepages(struct inode *inode);
1228
1229 void fuse_set_nowrite(struct inode *inode);
1230 void fuse_release_nowrite(struct inode *inode);
1231
1232 /**
1233  * Scan all fuse_mounts belonging to fc to find the first where
1234  * ilookup5() returns a result.  Return that result and the
1235  * respective fuse_mount in *fm (unless fm is NULL).
1236  *
1237  * The caller must hold fc->killsb.
1238  */
1239 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
1240                            struct fuse_mount **fm);
1241
1242 /**
1243  * File-system tells the kernel to invalidate cache for the given node id.
1244  */
1245 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
1246                              loff_t offset, loff_t len);
1247
1248 /**
1249  * File-system tells the kernel to invalidate parent attributes and
1250  * the dentry matching parent/name.
1251  *
1252  * If the child_nodeid is non-zero and:
1253  *    - matches the inode number for the dentry matching parent/name,
1254  *    - is not a mount point
1255  *    - is a file or oan empty directory
1256  * then the dentry is unhashed (d_delete()).
1257  */
1258 int fuse_reverse_inval_entry(struct fuse_conn *fc, u64 parent_nodeid,
1259                              u64 child_nodeid, struct qstr *name, u32 flags);
1260
1261 int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
1262                  bool isdir);
1263
1264 /**
1265  * fuse_direct_io() flags
1266  */
1267
1268 /** If set, it is WRITE; otherwise - READ */
1269 #define FUSE_DIO_WRITE (1 << 0)
1270
1271 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
1272 #define FUSE_DIO_CUSE  (1 << 1)
1273
1274 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1275                        loff_t *ppos, int flags);
1276 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1277                    unsigned int flags);
1278 long fuse_ioctl_common(struct file *file, unsigned int cmd,
1279                        unsigned long arg, unsigned int flags);
1280 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
1281 int fuse_dev_release(struct inode *inode, struct file *file);
1282
1283 bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written);
1284
1285 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
1286 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
1287
1288 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1289                     struct file *file);
1290
1291 void fuse_set_initialized(struct fuse_conn *fc);
1292
1293 void fuse_unlock_inode(struct inode *inode, bool locked);
1294 bool fuse_lock_inode(struct inode *inode);
1295
1296 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
1297                   size_t size, int flags, unsigned int extra_flags);
1298 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
1299                       size_t size);
1300 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
1301 int fuse_removexattr(struct inode *inode, const char *name);
1302 extern const struct xattr_handler * const fuse_xattr_handlers[];
1303
1304 struct posix_acl;
1305 struct posix_acl *fuse_get_inode_acl(struct inode *inode, int type, bool rcu);
1306 struct posix_acl *fuse_get_acl(struct mnt_idmap *idmap,
1307                                struct dentry *dentry, int type);
1308 int fuse_set_acl(struct mnt_idmap *, struct dentry *dentry,
1309                  struct posix_acl *acl, int type);
1310
1311 /* readdir.c */
1312 int fuse_readdir(struct file *file, struct dir_context *ctx);
1313
1314 /**
1315  * Return the number of bytes in an arguments list
1316  */
1317 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);
1318
1319 /**
1320  * Get the next unique ID for a request
1321  */
1322 u64 fuse_get_unique(struct fuse_iqueue *fiq);
1323 void fuse_free_conn(struct fuse_conn *fc);
1324
1325 /* dax.c */
1326
1327 #define FUSE_IS_DAX(inode) (IS_ENABLED(CONFIG_FUSE_DAX) && IS_DAX(inode))
1328
1329 ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to);
1330 ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from);
1331 int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma);
1332 int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start, u64 dmap_end);
1333 int fuse_dax_conn_alloc(struct fuse_conn *fc, enum fuse_dax_mode mode,
1334                         struct dax_device *dax_dev);
1335 void fuse_dax_conn_free(struct fuse_conn *fc);
1336 bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi);
1337 void fuse_dax_inode_init(struct inode *inode, unsigned int flags);
1338 void fuse_dax_inode_cleanup(struct inode *inode);
1339 void fuse_dax_dontcache(struct inode *inode, unsigned int flags);
1340 bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment);
1341 void fuse_dax_cancel_work(struct fuse_conn *fc);
1342
1343 /* ioctl.c */
1344 long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
1345 long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
1346                             unsigned long arg);
1347 int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa);
1348 int fuse_fileattr_set(struct mnt_idmap *idmap,
1349                       struct dentry *dentry, struct fileattr *fa);
1350
1351 /* file.c */
1352
1353 struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
1354                                  unsigned int open_flags, bool isdir);
1355 void fuse_file_release(struct inode *inode, struct fuse_file *ff,
1356                        unsigned int open_flags, fl_owner_t id, bool isdir);
1357
1358 #endif /* _FS_FUSE_I_H */