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