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/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 /** Maximum number of outstanding background requests */ 22 #define FUSE_MAX_BACKGROUND 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 /* 98 * The following bitfields are not changed during the request 99 * processing 100 */ 101 102 /** Last argument is variable length (can be shorter than 103 arg->size) */ 104 unsigned argvar:1; 105 106 /** Last argument is a list of pages to copy data to */ 107 unsigned argpages:1; 108 109 /** Zero partially or not copied pages */ 110 unsigned page_zeroing:1; 111 112 /** Number or arguments */ 113 unsigned numargs; 114 115 /** Array of arguments */ 116 struct fuse_arg args[3]; 117 }; 118 119 /** The request state */ 120 enum fuse_req_state { 121 FUSE_REQ_INIT = 0, 122 FUSE_REQ_PENDING, 123 FUSE_REQ_READING, 124 FUSE_REQ_SENT, 125 FUSE_REQ_FINISHED 126 }; 127 128 struct fuse_conn; 129 130 /** 131 * A request to the client 132 */ 133 struct fuse_req { 134 /** This can be on either pending processing or io lists in 135 fuse_conn */ 136 struct list_head list; 137 138 /** Entry on the background list */ 139 struct list_head bg_entry; 140 141 /** refcount */ 142 atomic_t count; 143 144 /* 145 * The following bitfields are either set once before the 146 * request is queued or setting/clearing them is protected by 147 * fuse_conn->lock 148 */ 149 150 /** True if the request has reply */ 151 unsigned isreply:1; 152 153 /** The request was interrupted */ 154 unsigned interrupted:1; 155 156 /** Request is sent in the background */ 157 unsigned background:1; 158 159 /** Data is being copied to/from the request */ 160 unsigned locked:1; 161 162 /** Request is counted as "waiting" */ 163 unsigned waiting:1; 164 165 /** State of the request */ 166 enum fuse_req_state state; 167 168 /** The request input */ 169 struct fuse_in in; 170 171 /** The request output */ 172 struct fuse_out out; 173 174 /** Used to wake up the task waiting for completion of request*/ 175 wait_queue_head_t waitq; 176 177 /** Data for asynchronous requests */ 178 union { 179 struct fuse_forget_in forget_in; 180 struct fuse_release_in release_in; 181 struct fuse_init_in init_in; 182 struct fuse_init_out init_out; 183 struct fuse_read_in read_in; 184 } misc; 185 186 /** page vector */ 187 struct page *pages[FUSE_MAX_PAGES_PER_REQ]; 188 189 /** number of pages in vector */ 190 unsigned num_pages; 191 192 /** offset of data on first page */ 193 unsigned page_offset; 194 195 /** Inode used in the request */ 196 struct inode *inode; 197 198 /** Second inode used in the request (or NULL) */ 199 struct inode *inode2; 200 201 /** File used in the request (or NULL) */ 202 struct file *file; 203 204 /** Request completion callback */ 205 void (*end)(struct fuse_conn *, struct fuse_req *); 206 }; 207 208 /** 209 * A Fuse connection. 210 * 211 * This structure is created, when the filesystem is mounted, and is 212 * destroyed, when the client device is closed and the filesystem is 213 * unmounted. 214 */ 215 struct fuse_conn { 216 /** Lock protecting accessess to members of this structure */ 217 spinlock_t lock; 218 219 /** The user id for this mount */ 220 uid_t user_id; 221 222 /** The group id for this mount */ 223 gid_t group_id; 224 225 /** The fuse mount flags for this mount */ 226 unsigned flags; 227 228 /** Maximum read size */ 229 unsigned max_read; 230 231 /** Maximum write size */ 232 unsigned max_write; 233 234 /** Readers of the connection are waiting on this */ 235 wait_queue_head_t waitq; 236 237 /** The list of pending requests */ 238 struct list_head pending; 239 240 /** The list of requests being processed */ 241 struct list_head processing; 242 243 /** The list of requests under I/O */ 244 struct list_head io; 245 246 /** Requests put in the background (RELEASE or any other 247 interrupted request) */ 248 struct list_head background; 249 250 /** Number of requests currently in the background */ 251 unsigned num_background; 252 253 /** Flag indicating if connection is blocked. This will be 254 the case before the INIT reply is received, and if there 255 are too many outstading backgrounds requests */ 256 int blocked; 257 258 /** waitq for blocked connection */ 259 wait_queue_head_t blocked_waitq; 260 261 /** RW semaphore for exclusion with fuse_put_super() */ 262 struct rw_semaphore sbput_sem; 263 264 /** The next unique request id */ 265 u64 reqctr; 266 267 /** Mount is active */ 268 unsigned mounted; 269 270 /** Connection established, cleared on umount, connection 271 abort and device release */ 272 unsigned connected; 273 274 /** Connection failed (version mismatch). Cannot race with 275 setting other bitfields since it is only set once in INIT 276 reply, before any other request, and never cleared */ 277 unsigned conn_error : 1; 278 279 /** Do readpages asynchronously? Only set in INIT */ 280 unsigned async_read : 1; 281 282 /* 283 * The following bitfields are only for optimization purposes 284 * and hence races in setting them will not cause malfunction 285 */ 286 287 /** Is fsync not implemented by fs? */ 288 unsigned no_fsync : 1; 289 290 /** Is fsyncdir not implemented by fs? */ 291 unsigned no_fsyncdir : 1; 292 293 /** Is flush not implemented by fs? */ 294 unsigned no_flush : 1; 295 296 /** Is setxattr not implemented by fs? */ 297 unsigned no_setxattr : 1; 298 299 /** Is getxattr not implemented by fs? */ 300 unsigned no_getxattr : 1; 301 302 /** Is listxattr not implemented by fs? */ 303 unsigned no_listxattr : 1; 304 305 /** Is removexattr not implemented by fs? */ 306 unsigned no_removexattr : 1; 307 308 /** Is access not implemented by fs? */ 309 unsigned no_access : 1; 310 311 /** Is create not implemented by fs? */ 312 unsigned no_create : 1; 313 314 /** The number of requests waiting for completion */ 315 atomic_t num_waiting; 316 317 /** Negotiated minor version */ 318 unsigned minor; 319 320 /** Backing dev info */ 321 struct backing_dev_info bdi; 322 323 /** kobject */ 324 struct kobject kobj; 325 326 /** O_ASYNC requests */ 327 struct fasync_struct *fasync; 328 }; 329 330 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) 331 { 332 return sb->s_fs_info; 333 } 334 335 static inline struct fuse_conn *get_fuse_conn(struct inode *inode) 336 { 337 return get_fuse_conn_super(inode->i_sb); 338 } 339 340 static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj) 341 { 342 return container_of(obj, struct fuse_conn, kobj); 343 } 344 345 static inline struct fuse_inode *get_fuse_inode(struct inode *inode) 346 { 347 return container_of(inode, struct fuse_inode, inode); 348 } 349 350 static inline u64 get_node_id(struct inode *inode) 351 { 352 return get_fuse_inode(inode)->nodeid; 353 } 354 355 /** Device operations */ 356 extern const struct file_operations fuse_dev_operations; 357 358 /** 359 * Get a filled in inode 360 */ 361 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, 362 int generation, struct fuse_attr *attr); 363 364 /** 365 * Send FORGET command 366 */ 367 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, 368 unsigned long nodeid, u64 nlookup); 369 370 /** 371 * Initialize READ or READDIR request 372 */ 373 void fuse_read_fill(struct fuse_req *req, struct file *file, 374 struct inode *inode, loff_t pos, size_t count, int opcode); 375 376 /** 377 * Send OPEN or OPENDIR request 378 */ 379 int fuse_open_common(struct inode *inode, struct file *file, int isdir); 380 381 struct fuse_file *fuse_file_alloc(void); 382 void fuse_file_free(struct fuse_file *ff); 383 void fuse_finish_open(struct inode *inode, struct file *file, 384 struct fuse_file *ff, struct fuse_open_out *outarg); 385 386 /** 387 * Send a RELEASE request 388 */ 389 void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff, 390 u64 nodeid, struct inode *inode, int flags, int isdir); 391 392 /** 393 * Send RELEASE or RELEASEDIR request 394 */ 395 int fuse_release_common(struct inode *inode, struct file *file, int isdir); 396 397 /** 398 * Send FSYNC or FSYNCDIR request 399 */ 400 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, 401 int isdir); 402 403 /** 404 * Initialize file operations on a regular file 405 */ 406 void fuse_init_file_inode(struct inode *inode); 407 408 /** 409 * Initialize inode operations on regular files and special files 410 */ 411 void fuse_init_common(struct inode *inode); 412 413 /** 414 * Initialize inode and file operations on a directory 415 */ 416 void fuse_init_dir(struct inode *inode); 417 418 /** 419 * Initialize inode operations on a symlink 420 */ 421 void fuse_init_symlink(struct inode *inode); 422 423 /** 424 * Change attributes of an inode 425 */ 426 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr); 427 428 /** 429 * Initialize the client device 430 */ 431 int fuse_dev_init(void); 432 433 /** 434 * Cleanup the client device 435 */ 436 void fuse_dev_cleanup(void); 437 438 /** 439 * Allocate a request 440 */ 441 struct fuse_req *fuse_request_alloc(void); 442 443 /** 444 * Free a request 445 */ 446 void fuse_request_free(struct fuse_req *req); 447 448 /** 449 * Reinitialize a request, the preallocated flag is left unmodified 450 */ 451 void fuse_reset_request(struct fuse_req *req); 452 453 /** 454 * Reserve a preallocated request 455 */ 456 struct fuse_req *fuse_get_req(struct fuse_conn *fc); 457 458 /** 459 * Decrement reference count of a request. If count goes to zero free 460 * the request. 461 */ 462 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 463 464 /** 465 * Send a request (synchronous) 466 */ 467 void request_send(struct fuse_conn *fc, struct fuse_req *req); 468 469 /** 470 * Send a request with no reply 471 */ 472 void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); 473 474 /** 475 * Send a request in the background 476 */ 477 void request_send_background(struct fuse_conn *fc, struct fuse_req *req); 478 479 /** 480 * Release inodes and file associated with background request 481 */ 482 void fuse_release_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