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         unsigned long 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_FINISHED
 135 };
 136
 137 struct fuse_conn;
 138
 139 /**
 140  * A request to the client
 141  */
 142 struct fuse_req {
 143         /** This can be on either pending processing or io lists in
 144             fuse_conn */
 145         struct list_head list;
 146
 147         /** refcount */
 148         atomic_t count;
 149
 150         /*
 151          * The following bitfields are either set once before the
 152          * request is queued or setting/clearing them is protected by
 153          * fuse_conn->lock
 154          */
 155
 156         /** True if the request has reply */
 157         unsigned isreply:1;
 158
 159         /** Force sending of the request even if interrupted */
 160         unsigned force:1;
 161
 162         /** The request was aborted */
 163         unsigned aborted:1;
 164
 165         /** Request is sent in the background */
 166         unsigned background:1;
 167
 168         /** Data is being copied to/from the request */
 169         unsigned locked:1;
 170
 171         /** Request is counted as "waiting" */
 172         unsigned waiting:1;
 173
 174         /** State of the request */
 175         enum fuse_req_state state;
 176
 177         /** The request input */
 178         struct fuse_in in;
 179
 180         /** The request output */
 181         struct fuse_out out;
 182
 183         /** Used to wake up the task waiting for completion of request*/
 184         wait_queue_head_t waitq;
 185
 186         /** Data for asynchronous requests */
 187         union {
 188                 struct fuse_forget_in forget_in;
 189                 struct fuse_release_in release_in;
 190                 struct fuse_init_in init_in;
 191                 struct fuse_init_out init_out;
 192                 struct fuse_read_in read_in;
 193                 struct fuse_lk_in lk_in;
 194         } misc;
 195
 196         /** page vector */
 197         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 198
 199         /** number of pages in vector */
 200         unsigned num_pages;
 201
 202         /** offset of data on first page */
 203         unsigned page_offset;
 204
 205         /** File used in the request (or NULL) */
 206         struct file *file;
 207
 208         /** vfsmount used in release */
 209         struct vfsmount *vfsmount;
 210
 211         /** dentry used in release */
 212         struct dentry *dentry;
 213
 214         /** Request completion callback */
 215         void (*end)(struct fuse_conn *, struct fuse_req *);
 216
 217         /** Request is stolen from fuse_file->reserved_req */
 218         struct file *stolen_file;
 219 };
 220
 221 /**
 222  * A Fuse connection.
 223  *
 224  * This structure is created, when the filesystem is mounted, and is
 225  * destroyed, when the client device is closed and the filesystem is
 226  * unmounted.
 227  */
 228 struct fuse_conn {
 229         /** Lock protecting accessess to  members of this structure */
 230         spinlock_t lock;
 231
 232         /** Refcount */
 233         atomic_t count;
 234
 235         /** The user id for this mount */
 236         uid_t user_id;
 237
 238         /** The group id for this mount */
 239         gid_t group_id;
 240
 241         /** The fuse mount flags for this mount */
 242         unsigned flags;
 243
 244         /** Maximum read size */
 245         unsigned max_read;
 246
 247         /** Maximum write size */
 248         unsigned max_write;
 249
 250         /** Readers of the connection are waiting on this */
 251         wait_queue_head_t waitq;
 252
 253         /** The list of pending requests */
 254         struct list_head pending;
 255
 256         /** The list of requests being processed */
 257         struct list_head processing;
 258
 259         /** The list of requests under I/O */
 260         struct list_head io;
 261
 262         /** Number of requests currently in the background */
 263         unsigned num_background;
 264
 265         /** Flag indicating if connection is blocked.  This will be
 266             the case before the INIT reply is received, and if there
 267             are too many outstading backgrounds requests */
 268         int blocked;
 269
 270         /** waitq for blocked connection */
 271         wait_queue_head_t blocked_waitq;
 272
 273         /** The next unique request id */
 274         u64 reqctr;
 275
 276         /** Connection established, cleared on umount, connection
 277             abort and device release */
 278         unsigned connected;
 279
 280         /** Connection failed (version mismatch).  Cannot race with
 281             setting other bitfields since it is only set once in INIT
 282             reply, before any other request, and never cleared */
 283         unsigned conn_error : 1;
 284
 285         /** Do readpages asynchronously?  Only set in INIT */
 286         unsigned async_read : 1;
 287
 288         /*
 289          * The following bitfields are only for optimization purposes
 290          * and hence races in setting them will not cause malfunction
 291          */
 292
 293         /** Is fsync not implemented by fs? */
 294         unsigned no_fsync : 1;
 295
 296         /** Is fsyncdir not implemented by fs? */
 297         unsigned no_fsyncdir : 1;
 298
 299         /** Is flush not implemented by fs? */
 300         unsigned no_flush : 1;
 301
 302         /** Is setxattr not implemented by fs? */
 303         unsigned no_setxattr : 1;
 304
 305         /** Is getxattr not implemented by fs? */
 306         unsigned no_getxattr : 1;
 307
 308         /** Is listxattr not implemented by fs? */
 309         unsigned no_listxattr : 1;
 310
 311         /** Is removexattr not implemented by fs? */
 312         unsigned no_removexattr : 1;
 313
 314         /** Are file locking primitives not implemented by fs? */
 315         unsigned no_lock : 1;
 316
 317         /** Is access not implemented by fs? */
 318         unsigned no_access : 1;
 319
 320         /** Is create not implemented by fs? */
 321         unsigned no_create : 1;
 322
 323         /** The number of requests waiting for completion */
 324         atomic_t num_waiting;
 325
 326         /** Negotiated minor version */
 327         unsigned minor;
 328
 329         /** Backing dev info */
 330         struct backing_dev_info bdi;
 331
 332         /** Entry on the fuse_conn_list */
 333         struct list_head entry;
 334
 335         /** Unique ID */
 336         u64 id;
 337
 338         /** Dentries in the control filesystem */
 339         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 340
 341         /** number of dentries used in the above array */
 342         int ctl_ndents;
 343
 344         /** O_ASYNC requests */
 345         struct fasync_struct *fasync;
 346 };
 347
 348 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 349 {
 350         return sb->s_fs_info;
 351 }
 352
 353 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 354 {
 355         return get_fuse_conn_super(inode->i_sb);
 356 }
 357
 358 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 359 {
 360         return container_of(inode, struct fuse_inode, inode);
 361 }
 362
 363 static inline u64 get_node_id(struct inode *inode)
 364 {
 365         return get_fuse_inode(inode)->nodeid;
 366 }
 367
 368 /** Device operations */
 369 extern const struct file_operations fuse_dev_operations;
 370
 371 /**
 372  * Get a filled in inode
 373  */
 374 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 375                         int generation, struct fuse_attr *attr);
 376
 377 /**
 378  * Send FORGET command
 379  */
 380 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 381                       unsigned long nodeid, u64 nlookup);
 382
 383 /**
 384  * Initialize READ or READDIR request
 385  */
 386 void fuse_read_fill(struct fuse_req *req, struct file *file,
 387                     struct inode *inode, loff_t pos, size_t count, int opcode);
 388
 389 /**
 390  * Send OPEN or OPENDIR request
 391  */
 392 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
 393
 394 struct fuse_file *fuse_file_alloc(void);
 395 void fuse_file_free(struct fuse_file *ff);
 396 void fuse_finish_open(struct inode *inode, struct file *file,
 397                       struct fuse_file *ff, struct fuse_open_out *outarg);
 398
 399 /** */
 400 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
 401                                    int opcode);
 402 /**
 403  * Send RELEASE or RELEASEDIR request
 404  */
 405 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
 406
 407 /**
 408  * Send FSYNC or FSYNCDIR request
 409  */
 410 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 411                       int isdir);
 412
 413 /**
 414  * Initialize file operations on a regular file
 415  */
 416 void fuse_init_file_inode(struct inode *inode);
 417
 418 /**
 419  * Initialize inode operations on regular files and special files
 420  */
 421 void fuse_init_common(struct inode *inode);
 422
 423 /**
 424  * Initialize inode and file operations on a directory
 425  */
 426 void fuse_init_dir(struct inode *inode);
 427
 428 /**
 429  * Initialize inode operations on a symlink
 430  */
 431 void fuse_init_symlink(struct inode *inode);
 432
 433 /**
 434  * Change attributes of an inode
 435  */
 436 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
 437
 438 /**
 439  * Initialize the client device
 440  */
 441 int fuse_dev_init(void);
 442
 443 /**
 444  * Cleanup the client device
 445  */
 446 void fuse_dev_cleanup(void);
 447
 448 int fuse_ctl_init(void);
 449 void fuse_ctl_cleanup(void);
 450
 451 /**
 452  * Allocate a request
 453  */
 454 struct fuse_req *fuse_request_alloc(void);
 455
 456 /**
 457  * Free a request
 458  */
 459 void fuse_request_free(struct fuse_req *req);
 460
 461 /**
 462  * Get a request, may fail with -ENOMEM
 463  */
 464 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 465
 466 /**
 467  * Gets a requests for a file operation, always succeeds
 468  */
 469 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
 470
 471 /**
 472  * Decrement reference count of a request.  If count goes to zero free
 473  * the request.
 474  */
 475 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 476
 477 /**
 478  * Send a request (synchronous)
 479  */
 480 void request_send(struct fuse_conn *fc, struct fuse_req *req);
 481
 482 /**
 483  * Send a request with no reply
 484  */
 485 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 486
 487 /**
 488  * Send a request in the background
 489  */
 490 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 491
 492 /* Abort all requests */
 493 void fuse_abort_conn(struct fuse_conn *fc);
 494
 495 /**
 496  * Get the attributes of a file
 497  */
 498 int fuse_do_getattr(struct inode *inode);
 499
 500 /**
 501  * Invalidate inode attributes
 502  */
 503 void fuse_invalidate_attr(struct inode *inode);
 504
 505 /**
 506  * Acquire reference to fuse_conn
 507  */
 508 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 509
 510 /**
 511  * Release reference to fuse_conn
 512  */
 513 void fuse_conn_put(struct fuse_conn *fc);
 514
 515 /**
 516  * Add connection to control filesystem
 517  */
 518 int fuse_ctl_add_conn(struct fuse_conn *fc);
 519
 520 /**
 521  * Remove connection from control filesystem
 522  */
 523 void fuse_ctl_remove_conn(struct fuse_conn *fc);