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d8a5ba45 MS |
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 | ||
334f485d MS |
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 | ||
1d3d752b MS |
24 | /** It could be as large as PATH_MAX, but would that have any uses? */ |
25 | #define FUSE_NAME_MAX 1024 | |
26 | ||
1e9a4ed9 MS |
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 | ||
413ef8cb | 36 | |
d8a5ba45 MS |
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 | ||
9e6268db MS |
46 | /** Number of lookups on this inode */ |
47 | u64 nlookup; | |
48 | ||
e5e5558e MS |
49 | /** The request used for sending the FORGET message */ |
50 | struct fuse_req *forget_req; | |
51 | ||
d8a5ba45 MS |
52 | /** Time in jiffies until the file attributes are valid */ |
53 | unsigned long i_time; | |
54 | }; | |
55 | ||
b6aeaded MS |
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 | ||
334f485d MS |
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 | ||
095da6cb MS |
97 | /* |
98 | * The following bitfields are not changed during the request | |
99 | * processing | |
100 | */ | |
101 | ||
334f485d MS |
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 | ||
83cfd493 MS |
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 | ||
64c6d8ed MS |
128 | struct fuse_conn; |
129 | ||
334f485d MS |
130 | /** |
131 | * A request to the client | |
132 | */ | |
133 | struct fuse_req { | |
d77a1d5b MS |
134 | /** This can be on either unused_list, pending processing or |
135 | io lists in fuse_conn */ | |
334f485d MS |
136 | struct list_head list; |
137 | ||
1e9a4ed9 MS |
138 | /** Entry on the background list */ |
139 | struct list_head bg_entry; | |
140 | ||
334f485d MS |
141 | /** refcount */ |
142 | atomic_t count; | |
143 | ||
095da6cb MS |
144 | /* |
145 | * The following bitfields are either set once before the | |
146 | * request is queued or setting/clearing them is protected by | |
147 | * fuse_lock | |
148 | */ | |
149 | ||
334f485d MS |
150 | /** True if the request has reply */ |
151 | unsigned isreply:1; | |
152 | ||
153 | /** The request is preallocated */ | |
154 | unsigned preallocated:1; | |
155 | ||
156 | /** The request was interrupted */ | |
157 | unsigned interrupted:1; | |
158 | ||
159 | /** Request is sent in the background */ | |
160 | unsigned background:1; | |
161 | ||
162 | /** Data is being copied to/from the request */ | |
163 | unsigned locked:1; | |
164 | ||
83cfd493 MS |
165 | /** State of the request */ |
166 | enum fuse_req_state state; | |
334f485d MS |
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 { | |
e5e5558e | 179 | struct fuse_forget_in forget_in; |
b6aeaded | 180 | struct fuse_release_in release_in; |
3ec870d5 MS |
181 | struct fuse_init_in init_in; |
182 | struct fuse_init_out init_out; | |
361b1eb5 | 183 | struct fuse_read_in read_in; |
334f485d MS |
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; | |
64c6d8ed MS |
203 | |
204 | /** Request completion callback */ | |
205 | void (*end)(struct fuse_conn *, struct fuse_req *); | |
334f485d MS |
206 | }; |
207 | ||
d8a5ba45 MS |
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 { | |
d8a5ba45 MS |
216 | /** The user id for this mount */ |
217 | uid_t user_id; | |
218 | ||
87729a55 MS |
219 | /** The group id for this mount */ |
220 | gid_t group_id; | |
221 | ||
1e9a4ed9 MS |
222 | /** The fuse mount flags for this mount */ |
223 | unsigned flags; | |
224 | ||
db50b96c MS |
225 | /** Maximum read size */ |
226 | unsigned max_read; | |
227 | ||
413ef8cb MS |
228 | /** Maximum write size */ |
229 | unsigned max_write; | |
230 | ||
334f485d MS |
231 | /** Readers of the connection are waiting on this */ |
232 | wait_queue_head_t waitq; | |
233 | ||
234 | /** The list of pending requests */ | |
235 | struct list_head pending; | |
236 | ||
237 | /** The list of requests being processed */ | |
238 | struct list_head processing; | |
239 | ||
d77a1d5b MS |
240 | /** The list of requests under I/O */ |
241 | struct list_head io; | |
242 | ||
1e9a4ed9 MS |
243 | /** Requests put in the background (RELEASE or any other |
244 | interrupted request) */ | |
245 | struct list_head background; | |
246 | ||
334f485d MS |
247 | /** Controls the maximum number of outstanding requests */ |
248 | struct semaphore outstanding_sem; | |
249 | ||
250 | /** This counts the number of outstanding requests if | |
251 | outstanding_sem would go negative */ | |
252 | unsigned outstanding_debt; | |
253 | ||
1e9a4ed9 MS |
254 | /** RW semaphore for exclusion with fuse_put_super() */ |
255 | struct rw_semaphore sbput_sem; | |
256 | ||
334f485d MS |
257 | /** The list of unused requests */ |
258 | struct list_head unused_list; | |
259 | ||
260 | /** The next unique request id */ | |
261 | u64 reqctr; | |
262 | ||
1e9a4ed9 | 263 | /** Mount is active */ |
095da6cb | 264 | unsigned mounted; |
1e9a4ed9 | 265 | |
69a53bf2 MS |
266 | /** Connection established, cleared on umount, connection |
267 | abort and device release */ | |
095da6cb | 268 | unsigned connected; |
1e9a4ed9 | 269 | |
095da6cb MS |
270 | /** Connection failed (version mismatch). Cannot race with |
271 | setting other bitfields since it is only set once in INIT | |
272 | reply, before any other request, and never cleared */ | |
334f485d MS |
273 | unsigned conn_error : 1; |
274 | ||
9cd68455 MS |
275 | /** Do readpages asynchronously? Only set in INIT */ |
276 | unsigned async_read : 1; | |
277 | ||
095da6cb MS |
278 | /* |
279 | * The following bitfields are only for optimization purposes | |
280 | * and hence races in setting them will not cause malfunction | |
281 | */ | |
282 | ||
b6aeaded MS |
283 | /** Is fsync not implemented by fs? */ |
284 | unsigned no_fsync : 1; | |
285 | ||
82547981 MS |
286 | /** Is fsyncdir not implemented by fs? */ |
287 | unsigned no_fsyncdir : 1; | |
288 | ||
b6aeaded MS |
289 | /** Is flush not implemented by fs? */ |
290 | unsigned no_flush : 1; | |
291 | ||
92a8780e MS |
292 | /** Is setxattr not implemented by fs? */ |
293 | unsigned no_setxattr : 1; | |
294 | ||
295 | /** Is getxattr not implemented by fs? */ | |
296 | unsigned no_getxattr : 1; | |
297 | ||
298 | /** Is listxattr not implemented by fs? */ | |
299 | unsigned no_listxattr : 1; | |
300 | ||
301 | /** Is removexattr not implemented by fs? */ | |
302 | unsigned no_removexattr : 1; | |
303 | ||
31d40d74 MS |
304 | /** Is access not implemented by fs? */ |
305 | unsigned no_access : 1; | |
306 | ||
fd72faac MS |
307 | /** Is create not implemented by fs? */ |
308 | unsigned no_create : 1; | |
309 | ||
0cd5b885 MS |
310 | /** The number of requests waiting for completion */ |
311 | atomic_t num_waiting; | |
312 | ||
45714d65 MS |
313 | /** Negotiated minor version */ |
314 | unsigned minor; | |
315 | ||
d8a5ba45 MS |
316 | /** Backing dev info */ |
317 | struct backing_dev_info bdi; | |
f543f253 MS |
318 | |
319 | /** kobject */ | |
320 | struct kobject kobj; | |
d8a5ba45 MS |
321 | }; |
322 | ||
d8a5ba45 MS |
323 | static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) |
324 | { | |
6383bdaa | 325 | return sb->s_fs_info; |
d8a5ba45 MS |
326 | } |
327 | ||
328 | static inline struct fuse_conn *get_fuse_conn(struct inode *inode) | |
329 | { | |
330 | return get_fuse_conn_super(inode->i_sb); | |
331 | } | |
332 | ||
f543f253 MS |
333 | static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj) |
334 | { | |
335 | return container_of(obj, struct fuse_conn, kobj); | |
336 | } | |
337 | ||
d8a5ba45 MS |
338 | static inline struct fuse_inode *get_fuse_inode(struct inode *inode) |
339 | { | |
340 | return container_of(inode, struct fuse_inode, inode); | |
341 | } | |
342 | ||
343 | static inline u64 get_node_id(struct inode *inode) | |
344 | { | |
345 | return get_fuse_inode(inode)->nodeid; | |
346 | } | |
347 | ||
334f485d | 348 | /** Device operations */ |
4b6f5d20 | 349 | extern const struct file_operations fuse_dev_operations; |
334f485d | 350 | |
d8a5ba45 MS |
351 | /** |
352 | * This is the single global spinlock which protects FUSE's structures | |
353 | * | |
354 | * The following data is protected by this lock: | |
355 | * | |
334f485d | 356 | * - the private_data field of the device file |
d8a5ba45 | 357 | * - the s_fs_info field of the super block |
334f485d | 358 | * - unused_list, pending, processing lists in fuse_conn |
1e9a4ed9 | 359 | * - background list in fuse_conn |
334f485d | 360 | * - the unique request ID counter reqctr in fuse_conn |
d8a5ba45 | 361 | * - the sb (super_block) field in fuse_conn |
334f485d | 362 | * - the file (device file) field in fuse_conn |
d8a5ba45 MS |
363 | */ |
364 | extern spinlock_t fuse_lock; | |
365 | ||
e5e5558e MS |
366 | /** |
367 | * Get a filled in inode | |
368 | */ | |
369 | struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, | |
9e6268db | 370 | int generation, struct fuse_attr *attr); |
e5e5558e MS |
371 | |
372 | /** | |
373 | * Send FORGET command | |
374 | */ | |
375 | void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, | |
9e6268db | 376 | unsigned long nodeid, u64 nlookup); |
e5e5558e | 377 | |
04730fef | 378 | /** |
361b1eb5 | 379 | * Initialize READ or READDIR request |
04730fef | 380 | */ |
361b1eb5 MS |
381 | void fuse_read_fill(struct fuse_req *req, struct file *file, |
382 | struct inode *inode, loff_t pos, size_t count, int opcode); | |
04730fef MS |
383 | |
384 | /** | |
385 | * Send OPEN or OPENDIR request | |
386 | */ | |
387 | int fuse_open_common(struct inode *inode, struct file *file, int isdir); | |
388 | ||
fd72faac MS |
389 | struct fuse_file *fuse_file_alloc(void); |
390 | void fuse_file_free(struct fuse_file *ff); | |
391 | void fuse_finish_open(struct inode *inode, struct file *file, | |
392 | struct fuse_file *ff, struct fuse_open_out *outarg); | |
393 | ||
394 | /** | |
395 | * Send a RELEASE request | |
396 | */ | |
397 | void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff, | |
398 | u64 nodeid, struct inode *inode, int flags, int isdir); | |
399 | ||
04730fef MS |
400 | /** |
401 | * Send RELEASE or RELEASEDIR request | |
402 | */ | |
403 | int fuse_release_common(struct inode *inode, struct file *file, int isdir); | |
404 | ||
82547981 MS |
405 | /** |
406 | * Send FSYNC or FSYNCDIR request | |
407 | */ | |
408 | int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, | |
409 | int isdir); | |
410 | ||
b6aeaded | 411 | /** |
1779381d | 412 | * Initialize file operations on a regular file |
b6aeaded MS |
413 | */ |
414 | void fuse_init_file_inode(struct inode *inode); | |
415 | ||
e5e5558e | 416 | /** |
1779381d | 417 | * Initialize inode operations on regular files and special files |
e5e5558e MS |
418 | */ |
419 | void fuse_init_common(struct inode *inode); | |
420 | ||
421 | /** | |
1779381d | 422 | * Initialize inode and file operations on a directory |
e5e5558e MS |
423 | */ |
424 | void fuse_init_dir(struct inode *inode); | |
425 | ||
426 | /** | |
1779381d | 427 | * Initialize inode operations on a symlink |
e5e5558e MS |
428 | */ |
429 | void fuse_init_symlink(struct inode *inode); | |
430 | ||
431 | /** | |
432 | * Change attributes of an inode | |
433 | */ | |
434 | void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr); | |
435 | ||
334f485d MS |
436 | /** |
437 | * Initialize the client device | |
438 | */ | |
439 | int fuse_dev_init(void); | |
440 | ||
441 | /** | |
442 | * Cleanup the client device | |
443 | */ | |
444 | void fuse_dev_cleanup(void); | |
445 | ||
446 | /** | |
447 | * Allocate a request | |
448 | */ | |
449 | struct fuse_req *fuse_request_alloc(void); | |
450 | ||
451 | /** | |
452 | * Free a request | |
453 | */ | |
454 | void fuse_request_free(struct fuse_req *req); | |
455 | ||
456 | /** | |
457 | * Reinitialize a request, the preallocated flag is left unmodified | |
458 | */ | |
459 | void fuse_reset_request(struct fuse_req *req); | |
460 | ||
461 | /** | |
462 | * Reserve a preallocated request | |
463 | */ | |
464 | struct fuse_req *fuse_get_request(struct fuse_conn *fc); | |
465 | ||
334f485d MS |
466 | /** |
467 | * Decrement reference count of a request. If count goes to zero put | |
1779381d | 468 | * on unused list (preallocated) or free request (not preallocated). |
334f485d MS |
469 | */ |
470 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); | |
471 | ||
472 | /** | |
7c352bdf | 473 | * Send a request (synchronous) |
334f485d MS |
474 | */ |
475 | void request_send(struct fuse_conn *fc, struct fuse_req *req); | |
476 | ||
334f485d MS |
477 | /** |
478 | * Send a request with no reply | |
479 | */ | |
480 | void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); | |
481 | ||
482 | /** | |
483 | * Send a request in the background | |
484 | */ | |
485 | void request_send_background(struct fuse_conn *fc, struct fuse_req *req); | |
486 | ||
1e9a4ed9 | 487 | /** |
1779381d | 488 | * Release inodes and file associated with background request |
1e9a4ed9 MS |
489 | */ |
490 | void fuse_release_background(struct fuse_req *req); | |
491 | ||
69a53bf2 MS |
492 | /* Abort all requests */ |
493 | void fuse_abort_conn(struct fuse_conn *fc); | |
494 | ||
e5e5558e MS |
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); |