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