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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 | ||
33 | /** If the FUSE_KERNEL_CACHE flag is given, then cached data will not | |
34 | be flushed on open */ | |
35 | #define FUSE_KERNEL_CACHE (1 << 2) | |
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 | ||
114 | struct fuse_req; | |
115 | struct fuse_conn; | |
116 | ||
117 | /** | |
118 | * A request to the client | |
119 | */ | |
120 | struct fuse_req { | |
121 | /** This can be on either unused_list, pending or processing | |
122 | lists in fuse_conn */ | |
123 | struct list_head list; | |
124 | ||
1e9a4ed9 MS |
125 | /** Entry on the background list */ |
126 | struct list_head bg_entry; | |
127 | ||
334f485d MS |
128 | /** refcount */ |
129 | atomic_t count; | |
130 | ||
131 | /** True if the request has reply */ | |
132 | unsigned isreply:1; | |
133 | ||
134 | /** The request is preallocated */ | |
135 | unsigned preallocated:1; | |
136 | ||
137 | /** The request was interrupted */ | |
138 | unsigned interrupted:1; | |
139 | ||
140 | /** Request is sent in the background */ | |
141 | unsigned background:1; | |
142 | ||
143 | /** Data is being copied to/from the request */ | |
144 | unsigned locked:1; | |
145 | ||
146 | /** Request has been sent to userspace */ | |
147 | unsigned sent:1; | |
148 | ||
149 | /** The request is finished */ | |
150 | unsigned finished:1; | |
151 | ||
152 | /** The request input */ | |
153 | struct fuse_in in; | |
154 | ||
155 | /** The request output */ | |
156 | struct fuse_out out; | |
157 | ||
158 | /** Used to wake up the task waiting for completion of request*/ | |
159 | wait_queue_head_t waitq; | |
160 | ||
161 | /** Data for asynchronous requests */ | |
162 | union { | |
e5e5558e | 163 | struct fuse_forget_in forget_in; |
b6aeaded | 164 | struct fuse_release_in release_in; |
334f485d MS |
165 | struct fuse_init_in_out init_in_out; |
166 | } misc; | |
167 | ||
168 | /** page vector */ | |
169 | struct page *pages[FUSE_MAX_PAGES_PER_REQ]; | |
170 | ||
171 | /** number of pages in vector */ | |
172 | unsigned num_pages; | |
173 | ||
174 | /** offset of data on first page */ | |
175 | unsigned page_offset; | |
176 | ||
177 | /** Inode used in the request */ | |
178 | struct inode *inode; | |
179 | ||
180 | /** Second inode used in the request (or NULL) */ | |
181 | struct inode *inode2; | |
182 | ||
183 | /** File used in the request (or NULL) */ | |
184 | struct file *file; | |
185 | }; | |
186 | ||
d8a5ba45 MS |
187 | /** |
188 | * A Fuse connection. | |
189 | * | |
190 | * This structure is created, when the filesystem is mounted, and is | |
191 | * destroyed, when the client device is closed and the filesystem is | |
192 | * unmounted. | |
193 | */ | |
194 | struct fuse_conn { | |
1e9a4ed9 MS |
195 | /** Reference count */ |
196 | int count; | |
334f485d | 197 | |
d8a5ba45 MS |
198 | /** The user id for this mount */ |
199 | uid_t user_id; | |
200 | ||
1e9a4ed9 MS |
201 | /** The fuse mount flags for this mount */ |
202 | unsigned flags; | |
203 | ||
334f485d MS |
204 | /** Readers of the connection are waiting on this */ |
205 | wait_queue_head_t waitq; | |
206 | ||
207 | /** The list of pending requests */ | |
208 | struct list_head pending; | |
209 | ||
210 | /** The list of requests being processed */ | |
211 | struct list_head processing; | |
212 | ||
1e9a4ed9 MS |
213 | /** Requests put in the background (RELEASE or any other |
214 | interrupted request) */ | |
215 | struct list_head background; | |
216 | ||
334f485d MS |
217 | /** Controls the maximum number of outstanding requests */ |
218 | struct semaphore outstanding_sem; | |
219 | ||
220 | /** This counts the number of outstanding requests if | |
221 | outstanding_sem would go negative */ | |
222 | unsigned outstanding_debt; | |
223 | ||
1e9a4ed9 MS |
224 | /** RW semaphore for exclusion with fuse_put_super() */ |
225 | struct rw_semaphore sbput_sem; | |
226 | ||
334f485d MS |
227 | /** The list of unused requests */ |
228 | struct list_head unused_list; | |
229 | ||
230 | /** The next unique request id */ | |
231 | u64 reqctr; | |
232 | ||
1e9a4ed9 MS |
233 | /** Mount is active */ |
234 | unsigned mounted : 1; | |
235 | ||
236 | /** Connection established */ | |
237 | unsigned connected : 1; | |
238 | ||
334f485d MS |
239 | /** Connection failed (version mismatch) */ |
240 | unsigned conn_error : 1; | |
241 | ||
b6aeaded MS |
242 | /** Is fsync not implemented by fs? */ |
243 | unsigned no_fsync : 1; | |
244 | ||
245 | /** Is flush not implemented by fs? */ | |
246 | unsigned no_flush : 1; | |
247 | ||
92a8780e MS |
248 | /** Is setxattr not implemented by fs? */ |
249 | unsigned no_setxattr : 1; | |
250 | ||
251 | /** Is getxattr not implemented by fs? */ | |
252 | unsigned no_getxattr : 1; | |
253 | ||
254 | /** Is listxattr not implemented by fs? */ | |
255 | unsigned no_listxattr : 1; | |
256 | ||
257 | /** Is removexattr not implemented by fs? */ | |
258 | unsigned no_removexattr : 1; | |
259 | ||
d8a5ba45 MS |
260 | /** Backing dev info */ |
261 | struct backing_dev_info bdi; | |
262 | }; | |
263 | ||
e5e5558e MS |
264 | struct fuse_getdir_out_i { |
265 | int fd; | |
266 | void *file; /* Used by kernel only */ | |
267 | }; | |
268 | ||
d8a5ba45 MS |
269 | static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb) |
270 | { | |
271 | return (struct fuse_conn **) &sb->s_fs_info; | |
272 | } | |
273 | ||
274 | static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) | |
275 | { | |
276 | return *get_fuse_conn_super_p(sb); | |
277 | } | |
278 | ||
279 | static inline struct fuse_conn *get_fuse_conn(struct inode *inode) | |
280 | { | |
281 | return get_fuse_conn_super(inode->i_sb); | |
282 | } | |
283 | ||
284 | static inline struct fuse_inode *get_fuse_inode(struct inode *inode) | |
285 | { | |
286 | return container_of(inode, struct fuse_inode, inode); | |
287 | } | |
288 | ||
289 | static inline u64 get_node_id(struct inode *inode) | |
290 | { | |
291 | return get_fuse_inode(inode)->nodeid; | |
292 | } | |
293 | ||
334f485d MS |
294 | /** Device operations */ |
295 | extern struct file_operations fuse_dev_operations; | |
296 | ||
d8a5ba45 MS |
297 | /** |
298 | * This is the single global spinlock which protects FUSE's structures | |
299 | * | |
300 | * The following data is protected by this lock: | |
301 | * | |
334f485d | 302 | * - the private_data field of the device file |
d8a5ba45 | 303 | * - the s_fs_info field of the super block |
334f485d | 304 | * - unused_list, pending, processing lists in fuse_conn |
1e9a4ed9 | 305 | * - background list in fuse_conn |
334f485d | 306 | * - the unique request ID counter reqctr in fuse_conn |
d8a5ba45 | 307 | * - the sb (super_block) field in fuse_conn |
334f485d | 308 | * - the file (device file) field in fuse_conn |
d8a5ba45 MS |
309 | */ |
310 | extern spinlock_t fuse_lock; | |
311 | ||
e5e5558e MS |
312 | /** |
313 | * Get a filled in inode | |
314 | */ | |
315 | struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid, | |
9e6268db | 316 | int generation, struct fuse_attr *attr); |
e5e5558e MS |
317 | |
318 | /** | |
319 | * Send FORGET command | |
320 | */ | |
321 | void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req, | |
9e6268db | 322 | unsigned long nodeid, u64 nlookup); |
e5e5558e | 323 | |
b6aeaded MS |
324 | /** |
325 | * Initialise file operations on a regular file | |
326 | */ | |
327 | void fuse_init_file_inode(struct inode *inode); | |
328 | ||
e5e5558e MS |
329 | /** |
330 | * Initialise inode operations on regular files and special files | |
331 | */ | |
332 | void fuse_init_common(struct inode *inode); | |
333 | ||
334 | /** | |
335 | * Initialise inode and file operations on a directory | |
336 | */ | |
337 | void fuse_init_dir(struct inode *inode); | |
338 | ||
339 | /** | |
340 | * Initialise inode operations on a symlink | |
341 | */ | |
342 | void fuse_init_symlink(struct inode *inode); | |
343 | ||
344 | /** | |
345 | * Change attributes of an inode | |
346 | */ | |
347 | void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr); | |
348 | ||
d8a5ba45 MS |
349 | /** |
350 | * Check if the connection can be released, and if yes, then free the | |
351 | * connection structure | |
352 | */ | |
353 | void fuse_release_conn(struct fuse_conn *fc); | |
354 | ||
334f485d MS |
355 | /** |
356 | * Initialize the client device | |
357 | */ | |
358 | int fuse_dev_init(void); | |
359 | ||
360 | /** | |
361 | * Cleanup the client device | |
362 | */ | |
363 | void fuse_dev_cleanup(void); | |
364 | ||
365 | /** | |
366 | * Allocate a request | |
367 | */ | |
368 | struct fuse_req *fuse_request_alloc(void); | |
369 | ||
370 | /** | |
371 | * Free a request | |
372 | */ | |
373 | void fuse_request_free(struct fuse_req *req); | |
374 | ||
375 | /** | |
376 | * Reinitialize a request, the preallocated flag is left unmodified | |
377 | */ | |
378 | void fuse_reset_request(struct fuse_req *req); | |
379 | ||
380 | /** | |
381 | * Reserve a preallocated request | |
382 | */ | |
383 | struct fuse_req *fuse_get_request(struct fuse_conn *fc); | |
384 | ||
385 | /** | |
386 | * Reserve a preallocated request, only interruptible by SIGKILL | |
387 | */ | |
388 | struct fuse_req *fuse_get_request_nonint(struct fuse_conn *fc); | |
389 | ||
390 | /** | |
391 | * Decrement reference count of a request. If count goes to zero put | |
392 | * on unused list (preallocated) or free reqest (not preallocated). | |
393 | */ | |
394 | void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); | |
395 | ||
396 | /** | |
397 | * Send a request (synchronous, interruptible) | |
398 | */ | |
399 | void request_send(struct fuse_conn *fc, struct fuse_req *req); | |
400 | ||
401 | /** | |
402 | * Send a request (synchronous, non-interruptible except by SIGKILL) | |
403 | */ | |
404 | void request_send_nonint(struct fuse_conn *fc, struct fuse_req *req); | |
405 | ||
406 | /** | |
407 | * Send a request with no reply | |
408 | */ | |
409 | void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); | |
410 | ||
411 | /** | |
412 | * Send a request in the background | |
413 | */ | |
414 | void request_send_background(struct fuse_conn *fc, struct fuse_req *req); | |
415 | ||
1e9a4ed9 MS |
416 | /** |
417 | * Release inodes and file assiciated with background request | |
418 | */ | |
419 | void fuse_release_background(struct fuse_req *req); | |
420 | ||
e5e5558e MS |
421 | /** |
422 | * Get the attributes of a file | |
423 | */ | |
424 | int fuse_do_getattr(struct inode *inode); | |
425 | ||
426 | /** | |
427 | * Invalidate inode attributes | |
428 | */ | |
429 | void fuse_invalidate_attr(struct inode *inode); | |
430 | ||
334f485d MS |
431 | /** |
432 | * Send the INIT message | |
433 | */ | |
434 | void fuse_send_init(struct fuse_conn *fc); |