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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 | ||
1e9a4ed9 MS |
24 | /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem |
25 | module will check permissions based on the file mode. Otherwise no | |
26 | permission checking is done in the kernel */ | |
27 | #define FUSE_DEFAULT_PERMISSIONS (1 << 0) | |
28 | ||
29 | /** If the FUSE_ALLOW_OTHER flag is given, then not only the user | |
30 | doing the mount will be allowed to access the filesystem */ | |
31 | #define FUSE_ALLOW_OTHER (1 << 1) | |
32 | ||
413ef8cb | 33 | |
d8a5ba45 MS |
34 | /** FUSE inode */ |
35 | struct fuse_inode { | |
36 | /** Inode data */ | |
37 | struct inode inode; | |
38 | ||
39 | /** Unique ID, which identifies the inode between userspace | |
40 | * and kernel */ | |
41 | u64 nodeid; | |
42 | ||
9e6268db MS |
43 | /** Number of lookups on this inode */ |
44 | u64 nlookup; | |
45 | ||
e5e5558e MS |
46 | /** The request used for sending the FORGET message */ |
47 | struct fuse_req *forget_req; | |
48 | ||
d8a5ba45 MS |
49 | /** Time in jiffies until the file attributes are valid */ |
50 | unsigned long i_time; | |
51 | }; | |
52 | ||
b6aeaded MS |
53 | /** FUSE specific file data */ |
54 | struct fuse_file { | |
55 | /** Request reserved for flush and release */ | |
56 | struct fuse_req *release_req; | |
57 | ||
58 | /** File handle used by userspace */ | |
59 | u64 fh; | |
60 | }; | |
61 | ||
334f485d MS |
62 | /** One input argument of a request */ |
63 | struct fuse_in_arg { | |
64 | unsigned size; | |
65 | const void *value; | |
66 | }; | |
67 | ||
68 | /** The request input */ | |
69 | struct fuse_in { | |
70 | /** The request header */ | |
71 | struct fuse_in_header h; | |
72 | ||
73 | /** True if the data for the last argument is in req->pages */ | |
74 | unsigned argpages:1; | |
75 | ||
76 | /** Number of arguments */ | |
77 | unsigned numargs; | |
78 | ||
79 | /** Array of arguments */ | |
80 | struct fuse_in_arg args[3]; | |
81 | }; | |
82 | ||
83 | /** One output argument of a request */ | |
84 | struct fuse_arg { | |
85 | unsigned size; | |
86 | void *value; | |
87 | }; | |
88 | ||
89 | /** The request output */ | |
90 | struct fuse_out { | |
91 | /** Header returned from userspace */ | |
92 | struct fuse_out_header h; | |
93 | ||
94 | /** Last argument is variable length (can be shorter than | |
95 | arg->size) */ | |
96 | unsigned argvar:1; | |
97 | ||
98 | /** Last argument is a list of pages to copy data to */ | |
99 | unsigned argpages:1; | |
100 | ||
101 | /** Zero partially or not copied pages */ | |
102 | unsigned page_zeroing:1; | |
103 | ||
104 | /** Number or arguments */ | |
105 | unsigned numargs; | |
106 | ||
107 | /** Array of arguments */ | |
108 | struct fuse_arg args[3]; | |
109 | }; | |
110 | ||
111 | struct fuse_req; | |
112 | struct fuse_conn; | |
113 | ||
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; |
334f485d MS |
162 | struct fuse_init_in_out init_in_out; |
163 | } misc; | |
164 | ||
165 | /** page vector */ | |
166 | struct page *pages[FUSE_MAX_PAGES_PER_REQ]; | |
167 | ||
168 | /** number of pages in vector */ | |
169 | unsigned num_pages; | |
170 | ||
171 | /** offset of data on first page */ | |
172 | unsigned page_offset; | |
173 | ||
174 | /** Inode used in the request */ | |
175 | struct inode *inode; | |
176 | ||
177 | /** Second inode used in the request (or NULL) */ | |
178 | struct inode *inode2; | |
179 | ||
180 | /** File used in the request (or NULL) */ | |
181 | struct file *file; | |
182 | }; | |
183 | ||
d8a5ba45 MS |
184 | /** |
185 | * A Fuse connection. | |
186 | * | |
187 | * This structure is created, when the filesystem is mounted, and is | |
188 | * destroyed, when the client device is closed and the filesystem is | |
189 | * unmounted. | |
190 | */ | |
191 | struct fuse_conn { | |
1e9a4ed9 MS |
192 | /** Reference count */ |
193 | int count; | |
334f485d | 194 | |
d8a5ba45 MS |
195 | /** The user id for this mount */ |
196 | uid_t user_id; | |
197 | ||
87729a55 MS |
198 | /** The group id for this mount */ |
199 | gid_t group_id; | |
200 | ||
1e9a4ed9 MS |
201 | /** The fuse mount flags for this mount */ |
202 | unsigned flags; | |
203 | ||
db50b96c MS |
204 | /** Maximum read size */ |
205 | unsigned max_read; | |
206 | ||
413ef8cb MS |
207 | /** Maximum write size */ |
208 | unsigned max_write; | |
209 | ||
334f485d MS |
210 | /** Readers of the connection are waiting on this */ |
211 | wait_queue_head_t waitq; | |
212 | ||
213 | /** The list of pending requests */ | |
214 | struct list_head pending; | |
215 | ||
216 | /** The list of requests being processed */ | |
217 | struct list_head processing; | |
218 | ||
1e9a4ed9 MS |
219 | /** Requests put in the background (RELEASE or any other |
220 | interrupted request) */ | |
221 | struct list_head background; | |
222 | ||
334f485d MS |
223 | /** Controls the maximum number of outstanding requests */ |
224 | struct semaphore outstanding_sem; | |
225 | ||
226 | /** This counts the number of outstanding requests if | |
227 | outstanding_sem would go negative */ | |
228 | unsigned outstanding_debt; | |
229 | ||
1e9a4ed9 MS |
230 | /** RW semaphore for exclusion with fuse_put_super() */ |
231 | struct rw_semaphore sbput_sem; | |
232 | ||
334f485d MS |
233 | /** The list of unused requests */ |
234 | struct list_head unused_list; | |
235 | ||
236 | /** The next unique request id */ | |
237 | u64 reqctr; | |
238 | ||
1e9a4ed9 MS |
239 | /** Mount is active */ |
240 | unsigned mounted : 1; | |
241 | ||
242 | /** Connection established */ | |
243 | unsigned connected : 1; | |
244 | ||
334f485d MS |
245 | /** Connection failed (version mismatch) */ |
246 | unsigned conn_error : 1; | |
247 | ||
b6aeaded MS |
248 | /** Is fsync not implemented by fs? */ |
249 | unsigned no_fsync : 1; | |
250 | ||
82547981 MS |
251 | /** Is fsyncdir not implemented by fs? */ |
252 | unsigned no_fsyncdir : 1; | |
253 | ||
b6aeaded MS |
254 | /** Is flush not implemented by fs? */ |
255 | unsigned no_flush : 1; | |
256 | ||
92a8780e MS |
257 | /** Is setxattr not implemented by fs? */ |
258 | unsigned no_setxattr : 1; | |
259 | ||
260 | /** Is getxattr not implemented by fs? */ | |
261 | unsigned no_getxattr : 1; | |
262 | ||
263 | /** Is listxattr not implemented by fs? */ | |
264 | unsigned no_listxattr : 1; | |
265 | ||
266 | /** Is removexattr not implemented by fs? */ | |
267 | unsigned no_removexattr : 1; | |
268 | ||
d8a5ba45 MS |
269 | /** Backing dev info */ |
270 | struct backing_dev_info bdi; | |
271 | }; | |
272 | ||
273 | static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb) | |
274 | { | |
275 | return (struct fuse_conn **) &sb->s_fs_info; | |
276 | } | |
277 | ||
278 | static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) | |
279 | { | |
280 | return *get_fuse_conn_super_p(sb); | |
281 | } | |
282 | ||
283 | static inline struct fuse_conn *get_fuse_conn(struct inode *inode) | |
284 | { | |
285 | return get_fuse_conn_super(inode->i_sb); | |
286 | } | |
287 | ||
288 | static inline struct fuse_inode *get_fuse_inode(struct inode *inode) | |
289 | { | |
290 | return container_of(inode, struct fuse_inode, inode); | |
291 | } | |
292 | ||
293 | static inline u64 get_node_id(struct inode *inode) | |
294 | { | |
295 | return get_fuse_inode(inode)->nodeid; | |
296 | } | |
297 | ||
334f485d MS |
298 | /** Device operations */ |
299 | extern struct file_operations fuse_dev_operations; | |
300 | ||
d8a5ba45 MS |
301 | /** |
302 | * This is the single global spinlock which protects FUSE's structures | |
303 | * | |
304 | * The following data is protected by this lock: | |
305 | * | |
334f485d | 306 | * - the private_data field of the device file |
d8a5ba45 | 307 | * - the s_fs_info field of the super block |
334f485d | 308 | * - unused_list, pending, processing lists in fuse_conn |
1e9a4ed9 | 309 | * - background list in fuse_conn |
334f485d | 310 | * - the unique request ID counter reqctr in fuse_conn |
d8a5ba45 | 311 | * - the sb (super_block) field in fuse_conn |
334f485d | 312 | * - the file (device file) field in fuse_conn |
d8a5ba45 MS |
313 | */ |
314 | extern spinlock_t fuse_lock; | |
315 | ||
e5e5558e MS |
316 | /** |
317 | * Get a filled in inode | |
318 | */ | |
319 | struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, | |
9e6268db | 320 | int generation, struct fuse_attr *attr); |
e5e5558e MS |
321 | |
322 | /** | |
323 | * Send FORGET command | |
324 | */ | |
325 | void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, | |
9e6268db | 326 | unsigned long nodeid, u64 nlookup); |
e5e5558e | 327 | |
04730fef MS |
328 | /** |
329 | * Send READ or READDIR request | |
330 | */ | |
331 | size_t fuse_send_read_common(struct fuse_req *req, struct file *file, | |
332 | struct inode *inode, loff_t pos, size_t count, | |
333 | int isdir); | |
334 | ||
335 | /** | |
336 | * Send OPEN or OPENDIR request | |
337 | */ | |
338 | int fuse_open_common(struct inode *inode, struct file *file, int isdir); | |
339 | ||
340 | /** | |
341 | * Send RELEASE or RELEASEDIR request | |
342 | */ | |
343 | int fuse_release_common(struct inode *inode, struct file *file, int isdir); | |
344 | ||
82547981 MS |
345 | /** |
346 | * Send FSYNC or FSYNCDIR request | |
347 | */ | |
348 | int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, | |
349 | int isdir); | |
350 | ||
b6aeaded | 351 | /** |
1779381d | 352 | * Initialize file operations on a regular file |
b6aeaded MS |
353 | */ |
354 | void fuse_init_file_inode(struct inode *inode); | |
355 | ||
e5e5558e | 356 | /** |
1779381d | 357 | * Initialize inode operations on regular files and special files |
e5e5558e MS |
358 | */ |
359 | void fuse_init_common(struct inode *inode); | |
360 | ||
361 | /** | |
1779381d | 362 | * Initialize inode and file operations on a directory |
e5e5558e MS |
363 | */ |
364 | void fuse_init_dir(struct inode *inode); | |
365 | ||
366 | /** | |
1779381d | 367 | * Initialize inode operations on a symlink |
e5e5558e MS |
368 | */ |
369 | void fuse_init_symlink(struct inode *inode); | |
370 | ||
371 | /** | |
372 | * Change attributes of an inode | |
373 | */ | |
374 | void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr); | |
375 | ||
d8a5ba45 MS |
376 | /** |
377 | * Check if the connection can be released, and if yes, then free the | |
378 | * connection structure | |
379 | */ | |
380 | void fuse_release_conn(struct fuse_conn *fc); | |
381 | ||
334f485d MS |
382 | /** |
383 | * Initialize the client device | |
384 | */ | |
385 | int fuse_dev_init(void); | |
386 | ||
387 | /** | |
388 | * Cleanup the client device | |
389 | */ | |
390 | void fuse_dev_cleanup(void); | |
391 | ||
392 | /** | |
393 | * Allocate a request | |
394 | */ | |
395 | struct fuse_req *fuse_request_alloc(void); | |
396 | ||
397 | /** | |
398 | * Free a request | |
399 | */ | |
400 | void fuse_request_free(struct fuse_req *req); | |
401 | ||
402 | /** | |
403 | * Reinitialize a request, the preallocated flag is left unmodified | |
404 | */ | |
405 | void fuse_reset_request(struct fuse_req *req); | |
406 | ||
407 | /** | |
408 | * Reserve a preallocated request | |
409 | */ | |
410 | struct fuse_req *fuse_get_request(struct fuse_conn *fc); | |
411 | ||
334f485d MS |
412 | /** |
413 | * Decrement reference count of a request. If count goes to zero put | |
1779381d | 414 | * on unused list (preallocated) or free request (not preallocated). |
334f485d MS |
415 | */ |
416 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); | |
417 | ||
418 | /** | |
7c352bdf | 419 | * Send a request (synchronous) |
334f485d MS |
420 | */ |
421 | void request_send(struct fuse_conn *fc, struct fuse_req *req); | |
422 | ||
334f485d MS |
423 | /** |
424 | * Send a request with no reply | |
425 | */ | |
426 | void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); | |
427 | ||
428 | /** | |
429 | * Send a request in the background | |
430 | */ | |
431 | void request_send_background(struct fuse_conn *fc, struct fuse_req *req); | |
432 | ||
1e9a4ed9 | 433 | /** |
1779381d | 434 | * Release inodes and file associated with background request |
1e9a4ed9 MS |
435 | */ |
436 | void fuse_release_background(struct fuse_req *req); | |
437 | ||
e5e5558e MS |
438 | /** |
439 | * Get the attributes of a file | |
440 | */ | |
441 | int fuse_do_getattr(struct inode *inode); | |
442 | ||
443 | /** | |
444 | * Invalidate inode attributes | |
445 | */ | |
446 | void fuse_invalidate_attr(struct inode *inode); | |
447 | ||
334f485d MS |
448 | /** |
449 | * Send the INIT message | |
450 | */ | |
451 | void fuse_send_init(struct fuse_conn *fc); |