fs/fuse/fuse_i.h

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2005  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/wait.h>
  12 #include <linux/list.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/mm.h>
  15 #include <linux/backing-dev.h>
  16 #include <asm/semaphore.h>
  17
  18 /** Max number of pages that can be used in a single read request */
  19 #define FUSE_MAX_PAGES_PER_REQ 32
  20
  21 /** If more requests are outstanding, then the operation will block */
  22 #define FUSE_MAX_OUTSTANDING 10
  23
  24 /** It could be as large as PATH_MAX, but would that have any uses? */
  25 #define FUSE_NAME_MAX 1024
  26
  27 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
  28     module will check permissions based on the file mode.  Otherwise no
  29     permission checking is done in the kernel */
  30 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
  31
  32 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
  33     doing the mount will be allowed to access the filesystem */
  34 #define FUSE_ALLOW_OTHER         (1 << 1)
  35
  36
  37 /** FUSE inode */
  38 struct fuse_inode {
  39         /** Inode data */
  40         struct inode inode;
  41
  42         /** Unique ID, which identifies the inode between userspace
  43          * and kernel */
  44         u64 nodeid;
  45
  46         /** Number of lookups on this inode */
  47         u64 nlookup;
  48
  49         /** The request used for sending the FORGET message */
  50         struct fuse_req *forget_req;
  51
  52         /** Time in jiffies until the file attributes are valid */
  53         unsigned long i_time;
  54 };
  55
  56 /** FUSE specific file data */
  57 struct fuse_file {
  58         /** Request reserved for flush and release */
  59         struct fuse_req *release_req;
  60
  61         /** File handle used by userspace */
  62         u64 fh;
  63 };
  64
  65 /** One input argument of a request */
  66 struct fuse_in_arg {
  67         unsigned size;
  68         const void *value;
  69 };
  70
  71 /** The request input */
  72 struct fuse_in {
  73         /** The request header */
  74         struct fuse_in_header h;
  75
  76         /** True if the data for the last argument is in req->pages */
  77         unsigned argpages:1;
  78
  79         /** Number of arguments */
  80         unsigned numargs;
  81
  82         /** Array of arguments */
  83         struct fuse_in_arg args[3];
  84 };
  85
  86 /** One output argument of a request */
  87 struct fuse_arg {
  88         unsigned size;
  89         void *value;
  90 };
  91
  92 /** The request output */
  93 struct fuse_out {
  94         /** Header returned from userspace */
  95         struct fuse_out_header h;
  96
  97         /** Last argument is variable length (can be shorter than
  98             arg->size) */
  99         unsigned argvar:1;
 100
 101         /** Last argument is a list of pages to copy data to */
 102         unsigned argpages:1;
 103
 104         /** Zero partially or not copied pages */
 105         unsigned page_zeroing:1;
 106
 107         /** Number or arguments */
 108         unsigned numargs;
 109
 110         /** Array of arguments */
 111         struct fuse_arg args[3];
 112 };
 113
 114 /** The request state */
 115 enum fuse_req_state {
 116         FUSE_REQ_INIT = 0,
 117         FUSE_REQ_PENDING,
 118         FUSE_REQ_READING,
 119         FUSE_REQ_SENT,
 120         FUSE_REQ_FINISHED
 121 };
 122
 123 struct fuse_conn;
 124
 125 /**
 126  * A request to the client
 127  */
 128 struct fuse_req {
 129         /** This can be on either unused_list, pending processing or
 130             io lists in fuse_conn */
 131         struct list_head list;
 132
 133         /** Entry on the background list */
 134         struct list_head bg_entry;
 135
 136         /** refcount */
 137         atomic_t count;
 138
 139         /** True if the request has reply */
 140         unsigned isreply:1;
 141
 142         /** The request is preallocated */
 143         unsigned preallocated:1;
 144
 145         /** The request was interrupted */
 146         unsigned interrupted:1;
 147
 148         /** Request is sent in the background */
 149         unsigned background:1;
 150
 151         /** Data is being copied to/from the request */
 152         unsigned locked:1;
 153
 154         /** State of the request */
 155         enum fuse_req_state state;
 156
 157         /** The request input */
 158         struct fuse_in in;
 159
 160         /** The request output */
 161         struct fuse_out out;
 162
 163         /** Used to wake up the task waiting for completion of request*/
 164         wait_queue_head_t waitq;
 165
 166         /** Data for asynchronous requests */
 167         union {
 168                 struct fuse_forget_in forget_in;
 169                 struct fuse_release_in release_in;
 170                 struct fuse_init_in init_in;
 171                 struct fuse_init_out init_out;
 172         } misc;
 173
 174         /** page vector */
 175         struct page *pages[FUSE_MAX_PAGES_PER_REQ];
 176
 177         /** number of pages in vector */
 178         unsigned num_pages;
 179
 180         /** offset of data on first page */
 181         unsigned page_offset;
 182
 183         /** Inode used in the request */
 184         struct inode *inode;
 185
 186         /** Second inode used in the request (or NULL) */
 187         struct inode *inode2;
 188
 189         /** File used in the request (or NULL) */
 190         struct file *file;
 191
 192         /** Request completion callback */
 193         void (*end)(struct fuse_conn *, struct fuse_req *);
 194 };
 195
 196 /**
 197  * A Fuse connection.
 198  *
 199  * This structure is created, when the filesystem is mounted, and is
 200  * destroyed, when the client device is closed and the filesystem is
 201  * unmounted.
 202  */
 203 struct fuse_conn {
 204         /** The user id for this mount */
 205         uid_t user_id;
 206
 207         /** The group id for this mount */
 208         gid_t group_id;
 209
 210         /** The fuse mount flags for this mount */
 211         unsigned flags;
 212
 213         /** Maximum read size */
 214         unsigned max_read;
 215
 216         /** Maximum write size */
 217         unsigned max_write;
 218
 219         /** Readers of the connection are waiting on this */
 220         wait_queue_head_t waitq;
 221
 222         /** The list of pending requests */
 223         struct list_head pending;
 224
 225         /** The list of requests being processed */
 226         struct list_head processing;
 227
 228         /** The list of requests under I/O */
 229         struct list_head io;
 230
 231         /** Requests put in the background (RELEASE or any other
 232             interrupted request) */
 233         struct list_head background;
 234
 235         /** Controls the maximum number of outstanding requests */
 236         struct semaphore outstanding_sem;
 237
 238         /** This counts the number of outstanding requests if
 239             outstanding_sem would go negative */
 240         unsigned outstanding_debt;
 241
 242         /** RW semaphore for exclusion with fuse_put_super() */
 243         struct rw_semaphore sbput_sem;
 244
 245         /** The list of unused requests */
 246         struct list_head unused_list;
 247
 248         /** The next unique request id */
 249         u64 reqctr;
 250
 251         /** Mount is active */
 252         unsigned mounted : 1;
 253
 254         /** Connection established, cleared on umount, connection
 255             abort and device release */
 256         unsigned connected : 1;
 257
 258         /** Connection failed (version mismatch) */
 259         unsigned conn_error : 1;
 260
 261         /** Is fsync not implemented by fs? */
 262         unsigned no_fsync : 1;
 263
 264         /** Is fsyncdir not implemented by fs? */
 265         unsigned no_fsyncdir : 1;
 266
 267         /** Is flush not implemented by fs? */
 268         unsigned no_flush : 1;
 269
 270         /** Is setxattr not implemented by fs? */
 271         unsigned no_setxattr : 1;
 272
 273         /** Is getxattr not implemented by fs? */
 274         unsigned no_getxattr : 1;
 275
 276         /** Is listxattr not implemented by fs? */
 277         unsigned no_listxattr : 1;
 278
 279         /** Is removexattr not implemented by fs? */
 280         unsigned no_removexattr : 1;
 281
 282         /** Is access not implemented by fs? */
 283         unsigned no_access : 1;
 284
 285         /** Is create not implemented by fs? */
 286         unsigned no_create : 1;
 287
 288         /** The number of requests waiting for completion */
 289         atomic_t num_waiting;
 290
 291         /** Negotiated minor version */
 292         unsigned minor;
 293
 294         /** Backing dev info */
 295         struct backing_dev_info bdi;
 296
 297         /** kobject */
 298         struct kobject kobj;
 299 };
 300
 301 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
 302 {
 303         return sb->s_fs_info;
 304 }
 305
 306 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
 307 {
 308         return get_fuse_conn_super(inode->i_sb);
 309 }
 310
 311 static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj)
 312 {
 313         return container_of(obj, struct fuse_conn, kobj);
 314 }
 315
 316 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
 317 {
 318         return container_of(inode, struct fuse_inode, inode);
 319 }
 320
 321 static inline u64 get_node_id(struct inode *inode)
 322 {
 323         return get_fuse_inode(inode)->nodeid;
 324 }
 325
 326 /** Device operations */
 327 extern struct file_operations fuse_dev_operations;
 328
 329 /**
 330  * This is the single global spinlock which protects FUSE's structures
 331  *
 332  * The following data is protected by this lock:
 333  *
 334  *  - the private_data field of the device file
 335  *  - the s_fs_info field of the super block
 336  *  - unused_list, pending, processing lists in fuse_conn
 337  *  - background list in fuse_conn
 338  *  - the unique request ID counter reqctr in fuse_conn
 339  *  - the sb (super_block) field in fuse_conn
 340  *  - the file (device file) field in fuse_conn
 341  */
 342 extern spinlock_t fuse_lock;
 343
 344 /**
 345  * Get a filled in inode
 346  */
 347 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
 348                         int generation, struct fuse_attr *attr);
 349
 350 /**
 351  * Send FORGET command
 352  */
 353 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
 354                       unsigned long nodeid, u64 nlookup);
 355
 356 /**
 357  * Send READ or READDIR request
 358  */
 359 size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
 360                              struct inode *inode, loff_t pos, size_t count,
 361                              int isdir);
 362
 363 /**
 364  * Send OPEN or OPENDIR request
 365  */
 366 int fuse_open_common(struct inode *inode, struct file *file, int isdir);
 367
 368 struct fuse_file *fuse_file_alloc(void);
 369 void fuse_file_free(struct fuse_file *ff);
 370 void fuse_finish_open(struct inode *inode, struct file *file,
 371                       struct fuse_file *ff, struct fuse_open_out *outarg);
 372
 373 /**
 374  * Send a RELEASE request
 375  */
 376 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff,
 377                        u64 nodeid, struct inode *inode, int flags, int isdir);
 378
 379 /**
 380  * Send RELEASE or RELEASEDIR request
 381  */
 382 int fuse_release_common(struct inode *inode, struct file *file, int isdir);
 383
 384 /**
 385  * Send FSYNC or FSYNCDIR request
 386  */
 387 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 388                       int isdir);
 389
 390 /**
 391  * Initialize file operations on a regular file
 392  */
 393 void fuse_init_file_inode(struct inode *inode);
 394
 395 /**
 396  * Initialize inode operations on regular files and special files
 397  */
 398 void fuse_init_common(struct inode *inode);
 399
 400 /**
 401  * Initialize inode and file operations on a directory
 402  */
 403 void fuse_init_dir(struct inode *inode);
 404
 405 /**
 406  * Initialize inode operations on a symlink
 407  */
 408 void fuse_init_symlink(struct inode *inode);
 409
 410 /**
 411  * Change attributes of an inode
 412  */
 413 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
 414
 415 /**
 416  * Initialize the client device
 417  */
 418 int fuse_dev_init(void);
 419
 420 /**
 421  * Cleanup the client device
 422  */
 423 void fuse_dev_cleanup(void);
 424
 425 /**
 426  * Allocate a request
 427  */
 428 struct fuse_req *fuse_request_alloc(void);
 429
 430 /**
 431  * Free a request
 432  */
 433 void fuse_request_free(struct fuse_req *req);
 434
 435 /**
 436  * Reinitialize a request, the preallocated flag is left unmodified
 437  */
 438 void fuse_reset_request(struct fuse_req *req);
 439
 440 /**
 441  * Reserve a preallocated request
 442  */
 443 struct fuse_req *fuse_get_request(struct fuse_conn *fc);
 444
 445 /**
 446  * Decrement reference count of a request.  If count goes to zero put
 447  * on unused list (preallocated) or free request (not preallocated).
 448  */
 449 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 450
 451 /**
 452  * Send a request (synchronous)
 453  */
 454 void request_send(struct fuse_conn *fc, struct fuse_req *req);
 455
 456 /**
 457  * Send a request with no reply
 458  */
 459 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 460
 461 /**
 462  * Send a request in the background
 463  */
 464 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 465
 466 /**
 467  * Release inodes and file associated with background request
 468  */
 469 void fuse_release_background(struct fuse_req *req);
 470
 471 /* Abort all requests */
 472 void fuse_abort_conn(struct fuse_conn *fc);
 473
 474 /**
 475  * Get the attributes of a file
 476  */
 477 int fuse_do_getattr(struct inode *inode);
 478
 479 /**
 480  * Invalidate inode attributes
 481  */
 482 void fuse_invalidate_attr(struct inode *inode);
 483
 484 /**
 485  * Send the INIT message
 486  */
 487 void fuse_send_init(struct fuse_conn *fc);