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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 | ||
334f485d MS |
114 | /** |
115 | * A request to the client | |
116 | */ | |
117 | struct fuse_req { | |
118 | /** This can be on either unused_list, pending or processing | |
119 | lists in fuse_conn */ | |
120 | struct list_head list; | |
121 | ||
1e9a4ed9 MS |
122 | /** Entry on the background list */ |
123 | struct list_head bg_entry; | |
124 | ||
334f485d MS |
125 | /** refcount */ |
126 | atomic_t count; | |
127 | ||
128 | /** True if the request has reply */ | |
129 | unsigned isreply:1; | |
130 | ||
131 | /** The request is preallocated */ | |
132 | unsigned preallocated:1; | |
133 | ||
134 | /** The request was interrupted */ | |
135 | unsigned interrupted:1; | |
136 | ||
137 | /** Request is sent in the background */ | |
138 | unsigned background:1; | |
139 | ||
140 | /** Data is being copied to/from the request */ | |
141 | unsigned locked:1; | |
142 | ||
143 | /** Request has been sent to userspace */ | |
144 | unsigned sent:1; | |
145 | ||
146 | /** The request is finished */ | |
147 | unsigned finished:1; | |
148 | ||
149 | /** The request input */ | |
150 | struct fuse_in in; | |
151 | ||
152 | /** The request output */ | |
153 | struct fuse_out out; | |
154 | ||
155 | /** Used to wake up the task waiting for completion of request*/ | |
156 | wait_queue_head_t waitq; | |
157 | ||
158 | /** Data for asynchronous requests */ | |
159 | union { | |
e5e5558e | 160 | struct fuse_forget_in forget_in; |
b6aeaded | 161 | struct fuse_release_in release_in; |
3ec870d5 MS |
162 | struct fuse_init_in init_in; |
163 | struct fuse_init_out init_out; | |
334f485d MS |
164 | } misc; |
165 | ||
166 | /** page vector */ | |
167 | struct page *pages[FUSE_MAX_PAGES_PER_REQ]; | |
168 | ||
169 | /** number of pages in vector */ | |
170 | unsigned num_pages; | |
171 | ||
172 | /** offset of data on first page */ | |
173 | unsigned page_offset; | |
174 | ||
175 | /** Inode used in the request */ | |
176 | struct inode *inode; | |
177 | ||
178 | /** Second inode used in the request (or NULL) */ | |
179 | struct inode *inode2; | |
180 | ||
181 | /** File used in the request (or NULL) */ | |
182 | struct file *file; | |
183 | }; | |
184 | ||
d8a5ba45 MS |
185 | /** |
186 | * A Fuse connection. | |
187 | * | |
188 | * This structure is created, when the filesystem is mounted, and is | |
189 | * destroyed, when the client device is closed and the filesystem is | |
190 | * unmounted. | |
191 | */ | |
192 | struct fuse_conn { | |
1e9a4ed9 MS |
193 | /** Reference count */ |
194 | int count; | |
334f485d | 195 | |
d8a5ba45 MS |
196 | /** The user id for this mount */ |
197 | uid_t user_id; | |
198 | ||
87729a55 MS |
199 | /** The group id for this mount */ |
200 | gid_t group_id; | |
201 | ||
1e9a4ed9 MS |
202 | /** The fuse mount flags for this mount */ |
203 | unsigned flags; | |
204 | ||
db50b96c MS |
205 | /** Maximum read size */ |
206 | unsigned max_read; | |
207 | ||
413ef8cb MS |
208 | /** Maximum write size */ |
209 | unsigned max_write; | |
210 | ||
334f485d MS |
211 | /** Readers of the connection are waiting on this */ |
212 | wait_queue_head_t waitq; | |
213 | ||
214 | /** The list of pending requests */ | |
215 | struct list_head pending; | |
216 | ||
217 | /** The list of requests being processed */ | |
218 | struct list_head processing; | |
219 | ||
1e9a4ed9 MS |
220 | /** Requests put in the background (RELEASE or any other |
221 | interrupted request) */ | |
222 | struct list_head background; | |
223 | ||
334f485d MS |
224 | /** Controls the maximum number of outstanding requests */ |
225 | struct semaphore outstanding_sem; | |
226 | ||
227 | /** This counts the number of outstanding requests if | |
228 | outstanding_sem would go negative */ | |
229 | unsigned outstanding_debt; | |
230 | ||
1e9a4ed9 MS |
231 | /** RW semaphore for exclusion with fuse_put_super() */ |
232 | struct rw_semaphore sbput_sem; | |
233 | ||
334f485d MS |
234 | /** The list of unused requests */ |
235 | struct list_head unused_list; | |
236 | ||
237 | /** The next unique request id */ | |
238 | u64 reqctr; | |
239 | ||
1e9a4ed9 MS |
240 | /** Mount is active */ |
241 | unsigned mounted : 1; | |
242 | ||
243 | /** Connection established */ | |
244 | unsigned connected : 1; | |
245 | ||
334f485d MS |
246 | /** Connection failed (version mismatch) */ |
247 | unsigned conn_error : 1; | |
248 | ||
b6aeaded MS |
249 | /** Is fsync not implemented by fs? */ |
250 | unsigned no_fsync : 1; | |
251 | ||
82547981 MS |
252 | /** Is fsyncdir not implemented by fs? */ |
253 | unsigned no_fsyncdir : 1; | |
254 | ||
b6aeaded MS |
255 | /** Is flush not implemented by fs? */ |
256 | unsigned no_flush : 1; | |
257 | ||
92a8780e MS |
258 | /** Is setxattr not implemented by fs? */ |
259 | unsigned no_setxattr : 1; | |
260 | ||
261 | /** Is getxattr not implemented by fs? */ | |
262 | unsigned no_getxattr : 1; | |
263 | ||
264 | /** Is listxattr not implemented by fs? */ | |
265 | unsigned no_listxattr : 1; | |
266 | ||
267 | /** Is removexattr not implemented by fs? */ | |
268 | unsigned no_removexattr : 1; | |
269 | ||
31d40d74 MS |
270 | /** Is access not implemented by fs? */ |
271 | unsigned no_access : 1; | |
272 | ||
fd72faac MS |
273 | /** Is create not implemented by fs? */ |
274 | unsigned no_create : 1; | |
275 | ||
45714d65 MS |
276 | /** Negotiated minor version */ |
277 | unsigned minor; | |
278 | ||
d8a5ba45 MS |
279 | /** Backing dev info */ |
280 | struct backing_dev_info bdi; | |
281 | }; | |
282 | ||
283 | static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb) | |
284 | { | |
285 | return (struct fuse_conn **) &sb->s_fs_info; | |
286 | } | |
287 | ||
288 | static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) | |
289 | { | |
290 | return *get_fuse_conn_super_p(sb); | |
291 | } | |
292 | ||
293 | static inline struct fuse_conn *get_fuse_conn(struct inode *inode) | |
294 | { | |
295 | return get_fuse_conn_super(inode->i_sb); | |
296 | } | |
297 | ||
298 | static inline struct fuse_inode *get_fuse_inode(struct inode *inode) | |
299 | { | |
300 | return container_of(inode, struct fuse_inode, inode); | |
301 | } | |
302 | ||
303 | static inline u64 get_node_id(struct inode *inode) | |
304 | { | |
305 | return get_fuse_inode(inode)->nodeid; | |
306 | } | |
307 | ||
334f485d MS |
308 | /** Device operations */ |
309 | extern struct file_operations fuse_dev_operations; | |
310 | ||
d8a5ba45 MS |
311 | /** |
312 | * This is the single global spinlock which protects FUSE's structures | |
313 | * | |
314 | * The following data is protected by this lock: | |
315 | * | |
334f485d | 316 | * - the private_data field of the device file |
d8a5ba45 | 317 | * - the s_fs_info field of the super block |
334f485d | 318 | * - unused_list, pending, processing lists in fuse_conn |
1e9a4ed9 | 319 | * - background list in fuse_conn |
334f485d | 320 | * - the unique request ID counter reqctr in fuse_conn |
d8a5ba45 | 321 | * - the sb (super_block) field in fuse_conn |
334f485d | 322 | * - the file (device file) field in fuse_conn |
d8a5ba45 MS |
323 | */ |
324 | extern spinlock_t fuse_lock; | |
325 | ||
e5e5558e MS |
326 | /** |
327 | * Get a filled in inode | |
328 | */ | |
329 | struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, | |
9e6268db | 330 | int generation, struct fuse_attr *attr); |
e5e5558e MS |
331 | |
332 | /** | |
333 | * Send FORGET command | |
334 | */ | |
335 | void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, | |
9e6268db | 336 | unsigned long nodeid, u64 nlookup); |
e5e5558e | 337 | |
04730fef MS |
338 | /** |
339 | * Send READ or READDIR request | |
340 | */ | |
341 | size_t fuse_send_read_common(struct fuse_req *req, struct file *file, | |
342 | struct inode *inode, loff_t pos, size_t count, | |
343 | int isdir); | |
344 | ||
345 | /** | |
346 | * Send OPEN or OPENDIR request | |
347 | */ | |
348 | int fuse_open_common(struct inode *inode, struct file *file, int isdir); | |
349 | ||
fd72faac MS |
350 | struct fuse_file *fuse_file_alloc(void); |
351 | void fuse_file_free(struct fuse_file *ff); | |
352 | void fuse_finish_open(struct inode *inode, struct file *file, | |
353 | struct fuse_file *ff, struct fuse_open_out *outarg); | |
354 | ||
355 | /** | |
356 | * Send a RELEASE request | |
357 | */ | |
358 | void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff, | |
359 | u64 nodeid, struct inode *inode, int flags, int isdir); | |
360 | ||
04730fef MS |
361 | /** |
362 | * Send RELEASE or RELEASEDIR request | |
363 | */ | |
364 | int fuse_release_common(struct inode *inode, struct file *file, int isdir); | |
365 | ||
82547981 MS |
366 | /** |
367 | * Send FSYNC or FSYNCDIR request | |
368 | */ | |
369 | int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, | |
370 | int isdir); | |
371 | ||
b6aeaded | 372 | /** |
1779381d | 373 | * Initialize file operations on a regular file |
b6aeaded MS |
374 | */ |
375 | void fuse_init_file_inode(struct inode *inode); | |
376 | ||
e5e5558e | 377 | /** |
1779381d | 378 | * Initialize inode operations on regular files and special files |
e5e5558e MS |
379 | */ |
380 | void fuse_init_common(struct inode *inode); | |
381 | ||
382 | /** | |
1779381d | 383 | * Initialize inode and file operations on a directory |
e5e5558e MS |
384 | */ |
385 | void fuse_init_dir(struct inode *inode); | |
386 | ||
387 | /** | |
1779381d | 388 | * Initialize inode operations on a symlink |
e5e5558e MS |
389 | */ |
390 | void fuse_init_symlink(struct inode *inode); | |
391 | ||
392 | /** | |
393 | * Change attributes of an inode | |
394 | */ | |
395 | void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr); | |
396 | ||
d8a5ba45 MS |
397 | /** |
398 | * Check if the connection can be released, and if yes, then free the | |
399 | * connection structure | |
400 | */ | |
401 | void fuse_release_conn(struct fuse_conn *fc); | |
402 | ||
334f485d MS |
403 | /** |
404 | * Initialize the client device | |
405 | */ | |
406 | int fuse_dev_init(void); | |
407 | ||
408 | /** | |
409 | * Cleanup the client device | |
410 | */ | |
411 | void fuse_dev_cleanup(void); | |
412 | ||
413 | /** | |
414 | * Allocate a request | |
415 | */ | |
416 | struct fuse_req *fuse_request_alloc(void); | |
417 | ||
418 | /** | |
419 | * Free a request | |
420 | */ | |
421 | void fuse_request_free(struct fuse_req *req); | |
422 | ||
423 | /** | |
424 | * Reinitialize a request, the preallocated flag is left unmodified | |
425 | */ | |
426 | void fuse_reset_request(struct fuse_req *req); | |
427 | ||
428 | /** | |
429 | * Reserve a preallocated request | |
430 | */ | |
431 | struct fuse_req *fuse_get_request(struct fuse_conn *fc); | |
432 | ||
334f485d MS |
433 | /** |
434 | * Decrement reference count of a request. If count goes to zero put | |
1779381d | 435 | * on unused list (preallocated) or free request (not preallocated). |
334f485d MS |
436 | */ |
437 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); | |
438 | ||
439 | /** | |
7c352bdf | 440 | * Send a request (synchronous) |
334f485d MS |
441 | */ |
442 | void request_send(struct fuse_conn *fc, struct fuse_req *req); | |
443 | ||
334f485d MS |
444 | /** |
445 | * Send a request with no reply | |
446 | */ | |
447 | void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); | |
448 | ||
449 | /** | |
450 | * Send a request in the background | |
451 | */ | |
452 | void request_send_background(struct fuse_conn *fc, struct fuse_req *req); | |
453 | ||
1e9a4ed9 | 454 | /** |
1779381d | 455 | * Release inodes and file associated with background request |
1e9a4ed9 MS |
456 | */ |
457 | void fuse_release_background(struct fuse_req *req); | |
458 | ||
e5e5558e MS |
459 | /** |
460 | * Get the attributes of a file | |
461 | */ | |
462 | int fuse_do_getattr(struct inode *inode); | |
463 | ||
464 | /** | |
465 | * Invalidate inode attributes | |
466 | */ | |
467 | void fuse_invalidate_attr(struct inode *inode); | |
468 | ||
334f485d MS |
469 | /** |
470 | * Send the INIT message | |
471 | */ | |
472 | void fuse_send_init(struct fuse_conn *fc); |