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 *release_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 interrupted */
 163         unsigned interrupted: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
 218 /**
 219  * A Fuse connection.
 220  *
 221  * This structure is created, when the filesystem is mounted, and is
 222  * destroyed, when the client device is closed and the filesystem is
 223  * unmounted.
 224  */
 225 struct fuse_conn {
 226         /** Lock protecting accessess to  members of this structure */
 227         spinlock_t lock;
 228
 229         /** Refcount */
 230         atomic_t count;
 231
 232         /** The user id for this mount */
 233         uid_t user_id;
 234
 235         /** The group id for this mount */
 236         gid_t group_id;
 237
 238         /** The fuse mount flags for this mount */
 239         unsigned flags;
 240
 241         /** Maximum read size */
 242         unsigned max_read;
 243
 244         /** Maximum write size */
 245         unsigned max_write;
 246
 247         /** Readers of the connection are waiting on this */
 248         wait_queue_head_t waitq;
 249
 250         /** The list of pending requests */
 251         struct list_head pending;
 252
 253         /** The list of requests being processed */
 254         struct list_head processing;
 255
 256         /** The list of requests under I/O */
 257         struct list_head io;
 258
 259         /** Number of requests currently in the background */
 260         unsigned num_background;
 261
 262         /** Flag indicating if connection is blocked.  This will be
 263             the case before the INIT reply is received, and if there
 264             are too many outstading backgrounds requests */
 265         int blocked;
 266
 267         /** waitq for blocked connection */
 268         wait_queue_head_t blocked_waitq;
 269
 270         /** The next unique request id */
 271         u64 reqctr;
 272
 273         /** Connection established, cleared on umount, connection
 274             abort and device release */
 275         unsigned connected;
 276
 277         /** Connection failed (version mismatch).  Cannot race with
 278             setting other bitfields since it is only set once in INIT
 279             reply, before any other request, and never cleared */
 280         unsigned conn_error : 1;
 281
 282         /** Do readpages asynchronously?  Only set in INIT */
 283         unsigned async_read : 1;
 284
 285         /*
 286          * The following bitfields are only for optimization purposes
 287          * and hence races in setting them will not cause malfunction
 288          */
 289
 290         /** Is fsync not implemented by fs? */
 291         unsigned no_fsync : 1;
 292
 293         /** Is fsyncdir not implemented by fs? */
 294         unsigned no_fsyncdir : 1;
 295
 296         /** Is flush not implemented by fs? */
 297         unsigned no_flush : 1;
 298
 299         /** Is setxattr not implemented by fs? */
 300         unsigned no_setxattr : 1;
 301
 302         /** Is getxattr not implemented by fs? */
 303         unsigned no_getxattr : 1;
 304
 305         /** Is listxattr not implemented by fs? */
 306         unsigned no_listxattr : 1;
 307
 308         /** Is removexattr not implemented by fs? */
 309         unsigned no_removexattr : 1;
 310
 311         /** Are file locking primitives not implemented by fs? */
 312         unsigned no_lock : 1;
 313
 314         /** Is access not implemented by fs? */
 315         unsigned no_access : 1;
 316
 317         /** Is create not implemented by fs? */
 318         unsigned no_create : 1;
 319
 320         /** The number of requests waiting for completion */
 321         atomic_t num_waiting;
 322
 323         /** Negotiated minor version */
 324         unsigned minor;
 325
 326         /** Backing dev info */
 327         struct backing_dev_info bdi;
 328
 329         /** Entry on the fuse_conn_list */
 330         struct list_head entry;
 331
 332         /** Unique ID */
 333         u64 id;
 334
 335         /** Dentries in the control filesystem */
 336         struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
 337
 338         /** number of dentries used in the above array */
 339         int ctl_ndents;
 340
 341         /** O_ASYNC requests */
 342         struct fasync_struct *fasync;
 343 };
 344
 345 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 346 {
 347         return sb->s_fs_info;
 348 }
 349
 350 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 351 {
 352         return get_fuse_conn_super(inode->i_sb);
 353 }
 354
 355 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 356 {
 357         return container_of(inode, struct fuse_inode, inode);
 358 }
 359
 360 static inline u64 get_node_id(struct inode *inode)
 361 {
 362         return get_fuse_inode(inode)->nodeid;
 363 }
 364
 365 /** Device operations */
 366 extern const struct file_operations fuse_dev_operations;
 367
 368 /**
 369  * Get a filled in inode
 370  */
 371 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 372                         int generation, struct fuse_attr *attr);
 373
 374 /**
 375  * Send FORGET command
 376  */
 377 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 378                       unsigned long nodeid, u64 nlookup);
 379
 380 /**
 381  * Initialize READ or READDIR request
 382  */
 383 void fuse_read_fill(struct fuse_req *req, struct file *file,
 384                     struct inode *inode, loff_t pos, size_t count, int opcode);
 385
 386 /**
 387  * Send OPEN or OPENDIR request
 388  */
 389 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
 390
 391 struct fuse_file *fuse_file_alloc(void);
 392 void fuse_file_free(struct fuse_file *ff);
 393 void fuse_finish_open(struct inode *inode, struct file *file,
 394                       struct fuse_file *ff, struct fuse_open_out *outarg);
 395
 396 /** */
 397 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
 398                                    int opcode);
 399 /**
 400  * Send RELEASE or RELEASEDIR request
 401  */
 402 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
 403
 404 /**
 405  * Send FSYNC or FSYNCDIR request
 406  */
 407 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 408                       int isdir);
 409
 410 /**
 411  * Initialize file operations on a regular file
 412  */
 413 void fuse_init_file_inode(struct inode *inode);
 414
 415 /**
 416  * Initialize inode operations on regular files and special files
 417  */
 418 void fuse_init_common(struct inode *inode);
 419
 420 /**
 421  * Initialize inode and file operations on a directory
 422  */
 423 void fuse_init_dir(struct inode *inode);
 424
 425 /**
 426  * Initialize inode operations on a symlink
 427  */
 428 void fuse_init_symlink(struct inode *inode);
 429
 430 /**
 431  * Change attributes of an inode
 432  */
 433 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
 434
 435 /**
 436  * Initialize the client device
 437  */
 438 int fuse_dev_init(void);
 439
 440 /**
 441  * Cleanup the client device
 442  */
 443 void fuse_dev_cleanup(void);
 444
 445 int fuse_ctl_init(void);
 446 void fuse_ctl_cleanup(void);
 447
 448 /**
 449  * Allocate a request
 450  */
 451 struct fuse_req *fuse_request_alloc(void);
 452
 453 /**
 454  * Free a request
 455  */
 456 void fuse_request_free(struct fuse_req *req);
 457
 458 /**
 459  * Reserve a preallocated request
 460  */
 461 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
 462
 463 /**
 464  * Decrement reference count of a request.  If count goes to zero free
 465  * the request.
 466  */
 467 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 468
 469 /**
 470  * Send a request (synchronous)
 471  */
 472 void request_send(struct fuse_conn *fc, struct fuse_req *req);
 473
 474 /**
 475  * Send a request with no reply
 476  */
 477 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 478
 479 /**
 480  * Send a request in the background
 481  */
 482 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 483
 484 /* Abort all requests */
 485 void fuse_abort_conn(struct fuse_conn *fc);
 486
 487 /**
 488  * Get the attributes of a file
 489  */
 490 int fuse_do_getattr(struct inode *inode);
 491
 492 /**
 493  * Invalidate inode attributes
 494  */
 495 void fuse_invalidate_attr(struct inode *inode);
 496
 497 /**
 498  * Acquire reference to fuse_conn
 499  */
 500 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
 501
 502 /**
 503  * Release reference to fuse_conn
 504  */
 505 void fuse_conn_put(struct fuse_conn *fc);
 506
 507 /**
 508  * Add connection to control filesystem
 509  */
 510 int fuse_ctl_add_conn(struct fuse_conn *fc);
 511
 512 /**
 513  * Remove connection from control filesystem
 514  */
 515 void fuse_ctl_remove_conn(struct fuse_conn *fc);