fs/fuse/fuse_i.h

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2006  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 #include <linux/fuse.h>
  10 #include <linux/fs.h>
  11 #include <linux/mount.h>
  12 #include <linux/wait.h>
  13 #include <linux/list.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/mm.h>
  16 #include <linux/backing-dev.h>
  17 #include <linux/mutex.h>
  18
  19 /** Max number of pages that can be used in a single read request */
  20 #define FUSE_MAX_PAGES_PER_REQ 32
  21
  22 /** Maximum number of outstanding background requests */
  23 #define FUSE_MAX_BACKGROUND 12
  24
  25 /** Congestion starts at 75% of maximum */
  26 #define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
  27
  28 /** It could be as large as PATH_MAX, but would that have any uses? */
  29 #define FUSE_NAME_MAX 1024
  30
  31 /** Number of dentries for each connection in the control filesystem */
  32 #define FUSE_CTL_NUM_DENTRIES 3
  33
  34 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
  35     module will check permissions based on the file mode.  Otherwise no
  36     permission checking is done in the kernel */
  37 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
  38
  39 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
  40     doing the mount will be allowed to access the filesystem */
  41 #define FUSE_ALLOW_OTHER         (1 << 1)
  42
  43 /** List of active connections */
  44 extern struct list_head fuse_conn_list;
  45
  46 /** Global mutex protecting fuse_conn_list and the control filesystem */
  47 extern struct mutex fuse_mutex;
  48
  49 /** FUSE inode */
  50 struct fuse_inode {
  51         /** Inode data */
  52         struct inode inode;
  53
  54         /** Unique ID, which identifies the inode between userspace
  55          * and kernel */
  56         u64 nodeid;
  57
  58         /** Number of lookups on this inode */
  59         u64 nlookup;
  60
  61         /** The request used for sending the FORGET message */
  62         struct fuse_req *forget_req;
  63
  64         /** Time in jiffies until the file attributes are valid */
  65         u64 i_time;
  66 };
  67
  68 /** FUSE specific file data */
  69 struct fuse_file {
  70         /** Request reserved for flush and release */
  71         struct fuse_req *reserved_req;
  72
  73         /** File handle used by userspace */
  74         u64 fh;
  75 };
  76
  77 /** One input argument of a request */
  78 struct fuse_in_arg {
  79         unsigned size;
  80         const void *value;
  81 };
  82
  83 /** The request input */
  84 struct fuse_in {
  85         /** The request header */
  86         struct fuse_in_header h;
  87
  88         /** True if the data for the last argument is in req->pages */
  89         unsigned argpages:1;
  90
  91         /** Number of arguments */
  92         unsigned numargs;
  93
  94         /** Array of arguments */
  95         struct fuse_in_arg args[3];
  96 };
  97
  98 /** One output argument of a request */
  99 struct fuse_arg {
 100         unsigned size;
 101         void *value;
 102 };
 103
 104 /** The request output */
 105 struct fuse_out {
 106         /** Header returned from userspace */
 107         struct fuse_out_header h;
 108
 109         /*
 110          * The following bitfields are not changed during the request
 111          * processing
 112          */
 113
 114         /** Last argument is variable length (can be shorter than
 115             arg->size) */
 116         unsigned argvar:1;
 117
 118         /** Last argument is a list of pages to copy data to */
 119         unsigned argpages:1;
 120
 121         /** Zero partially or not copied pages */
 122         unsigned page_zeroing:1;
 123
 124         /** Number or arguments */
 125         unsigned numargs;
 126
 127         /** Array of arguments */
 128         struct fuse_arg args[3];
 129 };
 130
 131 /** The request state */
 132 enum fuse_req_state {
 133         FUSE_REQ_INIT = 0,
 134         FUSE_REQ_PENDING,
 135         FUSE_REQ_READING,
 136         FUSE_REQ_SENT,
 137         FUSE_REQ_WRITING,
 138         FUSE_REQ_FINISHED
 139 };
 140
 141 struct fuse_conn;
 142
 143 /**
 144  * A request to the client
 145  */
 146 struct fuse_req {
 147         /** This can be on either pending processing or io lists in
 148             fuse_conn */
 149         struct list_head list;
 150
 151         /** Entry on the interrupts list  */
 152         struct list_head intr_entry;
 153
 154         /** refcount */
 155         atomic_t count;
 156
 157         /** Unique ID for the interrupt request */
 158         u64 intr_unique;
 159
 160         /*
 161          * The following bitfields are either set once before the
 162          * request is queued or setting/clearing them is protected by
 163          * fuse_conn->lock
 164          */
 165
 166         /** True if the request has reply */
 167         unsigned isreply:1;
 168
 169         /** Force sending of the request even if interrupted */
 170         unsigned force:1;
 171
 172         /** The request was aborted */
 173         unsigned aborted:1;
 174
 175         /** Request is sent in the background */
 176         unsigned background:1;
 177
 178         /** The request has been interrupted */
 179         unsigned interrupted:1;
 180
 181         /** Data is being copied to/from the request */
 182         unsigned locked:1;
 183
 184         /** Request is counted as "waiting" */
 185         unsigned waiting:1;
 186
 187         /** State of the request */
 188         enum fuse_req_state state;
 189
 190         /** The request input */
 191         struct fuse_in in;
 192
 193         /** The request output */
 194         struct fuse_out out;
 195
 196         /** Used to wake up the task waiting for completion of request*/
 197         wait_queue_head_t waitq;
 198
 199         /** Data for asynchronous requests */
 200         union {
 201                 struct fuse_forget_in forget_in;
 202                 struct fuse_release_in release_in;
 203                 struct fuse_init_in init_in;
 204                 struct fuse_init_out init_out;
 205                 struct fuse_read_in read_in;
 206                 struct fuse_lk_in lk_in;
 207         } misc;
 208
 209         /** page vector */
 210         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 211
 212         /** number of pages in vector */
 213         unsigned num_pages;
 214
 215         /** offset of data on first page */
 216         unsigned page_offset;
 217
 218         /** File used in the request (or NULL) */
 219         struct file *file;
 220
 221         /** vfsmount used in release */
 222         struct vfsmount *vfsmount;
 223
 224         /** dentry used in release */
 225         struct dentry *dentry;
 226
 227         /** Request completion callback */
 228         void (*end)(struct fuse_conn *, struct fuse_req *);
 229
 230         /** Request is stolen from fuse_file->reserved_req */
 231         struct file *stolen_file;
 232 };
 233
 234 /**
 235  * A Fuse connection.
 236  *
 237  * This structure is created, when the filesystem is mounted, and is
 238  * destroyed, when the client device is closed and the filesystem is
 239  * unmounted.
 240  */
 241 struct fuse_conn {
 242         /** Lock protecting accessess to  members of this structure */
 243         spinlock_t lock;
 244
 245         /** Mutex protecting against directory alias creation */
 246         struct mutex inst_mutex;
 247
 248         /** Refcount */
 249         atomic_t count;
 250
 251         /** The user id for this mount */
 252         uid_t user_id;
 253
 254         /** The group id for this mount */
 255         gid_t group_id;
 256
 257         /** The fuse mount flags for this mount */
 258         unsigned flags;
 259
 260         /** Maximum read size */
 261         unsigned max_read;
 262
 263         /** Maximum write size */
 264         unsigned max_write;
 265
 266         /** Readers of the connection are waiting on this */
 267         wait_queue_head_t waitq;
 268
 269         /** The list of pending requests */
 270         struct list_head pending;
 271
 272         /** The list of requests being processed */
 273         struct list_head processing;
 274
 275         /** The list of requests under I/O */
 276         struct list_head io;
 277
 278         /** Number of requests currently in the background */
 279         unsigned num_background;
 280
 281         /** Pending interrupts */
 282         struct list_head interrupts;
 283
 284         /** Flag indicating if connection is blocked.  This will be
 285             the case before the INIT reply is received, and if there
 286             are too many outstading backgrounds requests */
 287         int blocked;
 288
 289         /** waitq for blocked connection */
 290         wait_queue_head_t blocked_waitq;
 291
 292         /** The next unique request id */
 293         u64 reqctr;
 294
 295         /** Connection established, cleared on umount, connection
 296             abort and device release */
 297         unsigned connected;
 298
 299         /** Connection failed (version mismatch).  Cannot race with
 300             setting other bitfields since it is only set once in INIT
 301             reply, before any other request, and never cleared */
 302         unsigned conn_error : 1;
 303
 304         /** Connection successful.  Only set in INIT */
 305         unsigned conn_init : 1;
 306
 307         /** Do readpages asynchronously?  Only set in INIT */
 308         unsigned async_read : 1;
 309
 310         /*
 311          * The following bitfields are only for optimization purposes
 312          * and hence races in setting them will not cause malfunction
 313          */
 314
 315         /** Is fsync not implemented by fs? */
 316         unsigned no_fsync : 1;
 317
 318         /** Is fsyncdir not implemented by fs? */
 319         unsigned no_fsyncdir : 1;
 320
 321         /** Is flush not implemented by fs? */
 322         unsigned no_flush : 1;
 323
 324         /** Is setxattr not implemented by fs? */
 325         unsigned no_setxattr : 1;
 326
 327         /** Is getxattr not implemented by fs? */
 328         unsigned no_getxattr : 1;
 329
 330         /** Is listxattr not implemented by fs? */
 331         unsigned no_listxattr : 1;
 332
 333         /** Is removexattr not implemented by fs? */
 334         unsigned no_removexattr : 1;
 335
 336         /** Are file locking primitives not implemented by fs? */
 337         unsigned no_lock : 1;
 338
 339         /** Is access not implemented by fs? */
 340         unsigned no_access : 1;
 341
 342         /** Is create not implemented by fs? */
 343         unsigned no_create : 1;
 344
 345         /** Is interrupt not implemented by fs? */
 346         unsigned no_interrupt : 1;
 347
 348         /** Is bmap not implemented by fs? */
 349         unsigned no_bmap : 1;
 350
 351         /** The number of requests waiting for completion */
 352         atomic_t num_waiting;
 353
 354         /** Negotiated minor version */
 355         unsigned minor;
 356
 357         /** Backing dev info */
 358         struct backing_dev_info bdi;
 359
 360         /** Entry on the fuse_conn_list */
 361         struct list_head entry;
 362
 363         /** Unique ID */
 364         u64 id;
 365
 366         /** Dentries in the control filesystem */
 367         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 368
 369         /** number of dentries used in the above array */
 370         int ctl_ndents;
 371
 372         /** O_ASYNC requests */
 373         struct fasync_struct *fasync;
 374
 375         /** Key for lock owner ID scrambling */
 376         u32 scramble_key[4];
 377
 378         /** Reserved request for the DESTROY message */
 379         struct fuse_req *destroy_req;
 380 };
 381
 382 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 383 {
 384         return sb->s_fs_info;
 385 }
 386
 387 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 388 {
 389         return get_fuse_conn_super(inode->i_sb);
 390 }
 391
 392 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 393 {
 394         return container_of(inode, struct fuse_inode, inode);
 395 }
 396
 397 static inline u64 get_node_id(struct inode *inode)
 398 {
 399         return get_fuse_inode(inode)->nodeid;
 400 }
 401
 402 /** Device operations */
 403 extern const struct file_operations fuse_dev_operations;
 404
 405 /**
 406  * Get a filled in inode
 407  */
 408 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 409                         int generation, struct fuse_attr *attr);
 410
 411 /**
 412  * Send FORGET command
 413  */
 414 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 415                       unsigned long nodeid, u64 nlookup);
 416
 417 /**
 418  * Initialize READ or READDIR request
 419  */
 420 void fuse_read_fill(struct fuse_req *req, struct file *file,
 421                     struct inode *inode, loff_t pos, size_t count, int opcode);
 422
 423 /**
 424  * Send OPEN or OPENDIR request
 425  */
 426 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
 427
 428 struct fuse_file *fuse_file_alloc(void);
 429 void fuse_file_free(struct fuse_file *ff);
 430 void fuse_finish_open(struct inode *inode, struct file *file,
 431                       struct fuse_file *ff, struct fuse_open_out *outarg);
 432
 433 /** */
 434 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
 435                                    int opcode);
 436 /**
 437  * Send RELEASE or RELEASEDIR request
 438  */
 439 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
 440
 441 /**
 442  * Send FSYNC or FSYNCDIR request
 443  */
 444 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 445                       int isdir);
 446
 447 /**
 448  * Initialize file operations on a regular file
 449  */
 450 void fuse_init_file_inode(struct inode *inode);
 451
 452 /**
 453  * Initialize inode operations on regular files and special files
 454  */
 455 void fuse_init_common(struct inode *inode);
 456
 457 /**
 458  * Initialize inode and file operations on a directory
 459  */
 460 void fuse_init_dir(struct inode *inode);
 461
 462 /**
 463  * Initialize inode operations on a symlink
 464  */
 465 void fuse_init_symlink(struct inode *inode);
 466
 467 /**
 468  * Change attributes of an inode
 469  */
 470 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
 471
 472 /**
 473  * Initialize the client device
 474  */
 475 int fuse_dev_init(void);
 476
 477 /**
 478  * Cleanup the client device
 479  */
 480 void fuse_dev_cleanup(void);
 481
 482 int fuse_ctl_init(void);
 483 void fuse_ctl_cleanup(void);
 484
 485 /**
 486  * Allocate a request
 487  */
 488 struct fuse_req *fuse_request_alloc(void);
 489
 490 /**
 491  * Free a request
 492  */
 493 void fuse_request_free(struct fuse_req *req);
 494
 495 /**
 496  * Get a request, may fail with -ENOMEM
 497  */
 498 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 499
 500 /**
 501  * Gets a requests for a file operation, always succeeds
 502  */
 503 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 504
 505 /**
 506  * Decrement reference count of a request.  If count goes to zero free
 507  * the request.
 508  */
 509 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 510
 511 /**
 512  * Send a request (synchronous)
 513  */
 514 void request_send(struct fuse_conn *fc, struct fuse_req *req);
 515
 516 /**
 517  * Send a request with no reply
 518  */
 519 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 520
 521 /**
 522  * Send a request in the background
 523  */
 524 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 525
 526 /* Abort all requests */
 527 void fuse_abort_conn(struct fuse_conn *fc);
 528
 529 /**
 530  * Get the attributes of a file
 531  */
 532 int fuse_do_getattr(struct inode *inode);
 533
 534 /**
 535  * Invalidate inode attributes
 536  */
 537 void fuse_invalidate_attr(struct inode *inode);
 538
 539 /**
 540  * Acquire reference to fuse_conn
 541  */
 542 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 543
 544 /**
 545  * Release reference to fuse_conn
 546  */
 547 void fuse_conn_put(struct fuse_conn *fc);
 548
 549 /**
 550  * Add connection to control filesystem
 551  */
 552 int fuse_ctl_add_conn(struct fuse_conn *fc);
 553
 554 /**
 555  * Remove connection from control filesystem
 556  */
 557 void fuse_ctl_remove_conn(struct fuse_conn *fc);
 558
 559 /**
 560  * Is file type valid?
 561  */
 562 int fuse_valid_type(int m);