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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 | ||
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 | ||
83cfd493 MS |
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 | ||
64c6d8ed MS |
123 | struct fuse_conn; |
124 | ||
334f485d MS |
125 | /** |
126 | * A request to the client | |
127 | */ | |
128 | struct fuse_req { | |
d77a1d5b MS |
129 | /** This can be on either unused_list, pending processing or |
130 | io lists in fuse_conn */ | |
334f485d MS |
131 | struct list_head list; |
132 | ||
1e9a4ed9 MS |
133 | /** Entry on the background list */ |
134 | struct list_head bg_entry; | |
135 | ||
334f485d MS |
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 | ||
83cfd493 MS |
154 | /** State of the request */ |
155 | enum fuse_req_state state; | |
334f485d MS |
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 { | |
e5e5558e | 168 | struct fuse_forget_in forget_in; |
b6aeaded | 169 | struct fuse_release_in release_in; |
3ec870d5 MS |
170 | struct fuse_init_in init_in; |
171 | struct fuse_init_out init_out; | |
334f485d MS |
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; | |
64c6d8ed MS |
191 | |
192 | /** Request completion callback */ | |
193 | void (*end)(struct fuse_conn *, struct fuse_req *); | |
334f485d MS |
194 | }; |
195 | ||
d8a5ba45 MS |
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 { | |
d8a5ba45 MS |
204 | /** The user id for this mount */ |
205 | uid_t user_id; | |
206 | ||
87729a55 MS |
207 | /** The group id for this mount */ |
208 | gid_t group_id; | |
209 | ||
1e9a4ed9 MS |
210 | /** The fuse mount flags for this mount */ |
211 | unsigned flags; | |
212 | ||
db50b96c MS |
213 | /** Maximum read size */ |
214 | unsigned max_read; | |
215 | ||
413ef8cb MS |
216 | /** Maximum write size */ |
217 | unsigned max_write; | |
218 | ||
334f485d MS |
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 | ||
d77a1d5b MS |
228 | /** The list of requests under I/O */ |
229 | struct list_head io; | |
230 | ||
1e9a4ed9 MS |
231 | /** Requests put in the background (RELEASE or any other |
232 | interrupted request) */ | |
233 | struct list_head background; | |
234 | ||
334f485d MS |
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 | ||
1e9a4ed9 MS |
242 | /** RW semaphore for exclusion with fuse_put_super() */ |
243 | struct rw_semaphore sbput_sem; | |
244 | ||
334f485d MS |
245 | /** The list of unused requests */ |
246 | struct list_head unused_list; | |
247 | ||
248 | /** The next unique request id */ | |
249 | u64 reqctr; | |
250 | ||
1e9a4ed9 MS |
251 | /** Mount is active */ |
252 | unsigned mounted : 1; | |
253 | ||
69a53bf2 MS |
254 | /** Connection established, cleared on umount, connection |
255 | abort and device release */ | |
1e9a4ed9 MS |
256 | unsigned connected : 1; |
257 | ||
334f485d MS |
258 | /** Connection failed (version mismatch) */ |
259 | unsigned conn_error : 1; | |
260 | ||
b6aeaded MS |
261 | /** Is fsync not implemented by fs? */ |
262 | unsigned no_fsync : 1; | |
263 | ||
82547981 MS |
264 | /** Is fsyncdir not implemented by fs? */ |
265 | unsigned no_fsyncdir : 1; | |
266 | ||
b6aeaded MS |
267 | /** Is flush not implemented by fs? */ |
268 | unsigned no_flush : 1; | |
269 | ||
92a8780e MS |
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 | ||
31d40d74 MS |
282 | /** Is access not implemented by fs? */ |
283 | unsigned no_access : 1; | |
284 | ||
fd72faac MS |
285 | /** Is create not implemented by fs? */ |
286 | unsigned no_create : 1; | |
287 | ||
0cd5b885 MS |
288 | /** The number of requests waiting for completion */ |
289 | atomic_t num_waiting; | |
290 | ||
45714d65 MS |
291 | /** Negotiated minor version */ |
292 | unsigned minor; | |
293 | ||
d8a5ba45 MS |
294 | /** Backing dev info */ |
295 | struct backing_dev_info bdi; | |
f543f253 MS |
296 | |
297 | /** kobject */ | |
298 | struct kobject kobj; | |
d8a5ba45 MS |
299 | }; |
300 | ||
d8a5ba45 MS |
301 | static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) |
302 | { | |
6383bdaa | 303 | return sb->s_fs_info; |
d8a5ba45 MS |
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 | ||
f543f253 MS |
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 | ||
d8a5ba45 MS |
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 | ||
334f485d MS |
326 | /** Device operations */ |
327 | extern struct file_operations fuse_dev_operations; | |
328 | ||
d8a5ba45 MS |
329 | /** |
330 | * This is the single global spinlock which protects FUSE's structures | |
331 | * | |
332 | * The following data is protected by this lock: | |
333 | * | |
334f485d | 334 | * - the private_data field of the device file |
d8a5ba45 | 335 | * - the s_fs_info field of the super block |
334f485d | 336 | * - unused_list, pending, processing lists in fuse_conn |
1e9a4ed9 | 337 | * - background list in fuse_conn |
334f485d | 338 | * - the unique request ID counter reqctr in fuse_conn |
d8a5ba45 | 339 | * - the sb (super_block) field in fuse_conn |
334f485d | 340 | * - the file (device file) field in fuse_conn |
d8a5ba45 MS |
341 | */ |
342 | extern spinlock_t fuse_lock; | |
343 | ||
e5e5558e MS |
344 | /** |
345 | * Get a filled in inode | |
346 | */ | |
347 | struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, | |
9e6268db | 348 | int generation, struct fuse_attr *attr); |
e5e5558e MS |
349 | |
350 | /** | |
351 | * Send FORGET command | |
352 | */ | |
353 | void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, | |
9e6268db | 354 | unsigned long nodeid, u64 nlookup); |
e5e5558e | 355 | |
04730fef MS |
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 | ||
fd72faac MS |
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 | ||
04730fef MS |
379 | /** |
380 | * Send RELEASE or RELEASEDIR request | |
381 | */ | |
382 | int fuse_release_common(struct inode *inode, struct file *file, int isdir); | |
383 | ||
82547981 MS |
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 | ||
b6aeaded | 390 | /** |
1779381d | 391 | * Initialize file operations on a regular file |
b6aeaded MS |
392 | */ |
393 | void fuse_init_file_inode(struct inode *inode); | |
394 | ||
e5e5558e | 395 | /** |
1779381d | 396 | * Initialize inode operations on regular files and special files |
e5e5558e MS |
397 | */ |
398 | void fuse_init_common(struct inode *inode); | |
399 | ||
400 | /** | |
1779381d | 401 | * Initialize inode and file operations on a directory |
e5e5558e MS |
402 | */ |
403 | void fuse_init_dir(struct inode *inode); | |
404 | ||
405 | /** | |
1779381d | 406 | * Initialize inode operations on a symlink |
e5e5558e MS |
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 | ||
334f485d MS |
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 | ||
334f485d MS |
445 | /** |
446 | * Decrement reference count of a request. If count goes to zero put | |
1779381d | 447 | * on unused list (preallocated) or free request (not preallocated). |
334f485d MS |
448 | */ |
449 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); | |
450 | ||
451 | /** | |
7c352bdf | 452 | * Send a request (synchronous) |
334f485d MS |
453 | */ |
454 | void request_send(struct fuse_conn *fc, struct fuse_req *req); | |
455 | ||
334f485d MS |
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 | ||
1e9a4ed9 | 466 | /** |
1779381d | 467 | * Release inodes and file associated with background request |
1e9a4ed9 MS |
468 | */ |
469 | void fuse_release_background(struct fuse_req *req); | |
470 | ||
69a53bf2 MS |
471 | /* Abort all requests */ |
472 | void fuse_abort_conn(struct fuse_conn *fc); | |
473 | ||
e5e5558e MS |
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); |