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Miklos Szeredid8a5ba42005-09-09 13:10:26 -07001/*
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
Miklos Szeredi334f4852005-09-09 13:10:27 -070018/** 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
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -070024/** 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
Miklos Szeredi413ef8c2005-09-09 13:10:35 -070033
Miklos Szeredid8a5ba42005-09-09 13:10:26 -070034/** FUSE inode */
35struct 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
Miklos Szeredi9e6268d2005-09-09 13:10:29 -070043 /** Number of lookups on this inode */
44 u64 nlookup;
45
Miklos Szeredie5e55582005-09-09 13:10:28 -070046 /** The request used for sending the FORGET message */
47 struct fuse_req *forget_req;
48
Miklos Szeredid8a5ba42005-09-09 13:10:26 -070049 /** Time in jiffies until the file attributes are valid */
50 unsigned long i_time;
51};
52
Miklos Szeredib6aeade2005-09-09 13:10:30 -070053/** FUSE specific file data */
54struct 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
Miklos Szeredi334f4852005-09-09 13:10:27 -070062/** One input argument of a request */
63struct fuse_in_arg {
64 unsigned size;
65 const void *value;
66};
67
68/** The request input */
69struct 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 */
84struct fuse_arg {
85 unsigned size;
86 void *value;
87};
88
89/** The request output */
90struct 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
111struct fuse_req;
112struct fuse_conn;
113
114/**
115 * A request to the client
116 */
117struct fuse_req {
118 /** This can be on either unused_list, pending or processing
119 lists in fuse_conn */
120 struct list_head list;
121
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700122 /** Entry on the background list */
123 struct list_head bg_entry;
124
Miklos Szeredi334f4852005-09-09 13:10:27 -0700125 /** 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 {
Miklos Szeredie5e55582005-09-09 13:10:28 -0700160 struct fuse_forget_in forget_in;
Miklos Szeredib6aeade2005-09-09 13:10:30 -0700161 struct fuse_release_in release_in;
Miklos Szeredi334f4852005-09-09 13:10:27 -0700162 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
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700184/**
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 */
191struct fuse_conn {
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700192 /** Reference count */
193 int count;
Miklos Szeredi334f4852005-09-09 13:10:27 -0700194
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700195 /** The user id for this mount */
196 uid_t user_id;
197
Miklos Szeredi87729a52005-09-09 13:10:34 -0700198 /** The group id for this mount */
199 gid_t group_id;
200
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700201 /** The fuse mount flags for this mount */
202 unsigned flags;
203
Miklos Szeredidb50b962005-09-09 13:10:33 -0700204 /** Maximum read size */
205 unsigned max_read;
206
Miklos Szeredi413ef8c2005-09-09 13:10:35 -0700207 /** Maximum write size */
208 unsigned max_write;
209
Miklos Szeredi334f4852005-09-09 13:10:27 -0700210 /** 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
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700219 /** Requests put in the background (RELEASE or any other
220 interrupted request) */
221 struct list_head background;
222
Miklos Szeredi334f4852005-09-09 13:10:27 -0700223 /** 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
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700230 /** RW semaphore for exclusion with fuse_put_super() */
231 struct rw_semaphore sbput_sem;
232
Miklos Szeredi334f4852005-09-09 13:10:27 -0700233 /** The list of unused requests */
234 struct list_head unused_list;
235
236 /** The next unique request id */
237 u64 reqctr;
238
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700239 /** Mount is active */
240 unsigned mounted : 1;
241
242 /** Connection established */
243 unsigned connected : 1;
244
Miklos Szeredi334f4852005-09-09 13:10:27 -0700245 /** Connection failed (version mismatch) */
246 unsigned conn_error : 1;
247
Miklos Szeredib6aeade2005-09-09 13:10:30 -0700248 /** Is fsync not implemented by fs? */
249 unsigned no_fsync : 1;
250
251 /** Is flush not implemented by fs? */
252 unsigned no_flush : 1;
253
Miklos Szeredi92a87802005-09-09 13:10:31 -0700254 /** Is setxattr not implemented by fs? */
255 unsigned no_setxattr : 1;
256
257 /** Is getxattr not implemented by fs? */
258 unsigned no_getxattr : 1;
259
260 /** Is listxattr not implemented by fs? */
261 unsigned no_listxattr : 1;
262
263 /** Is removexattr not implemented by fs? */
264 unsigned no_removexattr : 1;
265
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700266 /** Backing dev info */
267 struct backing_dev_info bdi;
268};
269
270static inline struct fuse_conn **get_fuse_conn_super_p(struct super_block *sb)
271{
272 return (struct fuse_conn **) &sb->s_fs_info;
273}
274
275static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
276{
277 return *get_fuse_conn_super_p(sb);
278}
279
280static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
281{
282 return get_fuse_conn_super(inode->i_sb);
283}
284
285static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
286{
287 return container_of(inode, struct fuse_inode, inode);
288}
289
290static inline u64 get_node_id(struct inode *inode)
291{
292 return get_fuse_inode(inode)->nodeid;
293}
294
Miklos Szeredi334f4852005-09-09 13:10:27 -0700295/** Device operations */
296extern struct file_operations fuse_dev_operations;
297
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700298/**
299 * This is the single global spinlock which protects FUSE's structures
300 *
301 * The following data is protected by this lock:
302 *
Miklos Szeredi334f4852005-09-09 13:10:27 -0700303 * - the private_data field of the device file
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700304 * - the s_fs_info field of the super block
Miklos Szeredi334f4852005-09-09 13:10:27 -0700305 * - unused_list, pending, processing lists in fuse_conn
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700306 * - background list in fuse_conn
Miklos Szeredi334f4852005-09-09 13:10:27 -0700307 * - the unique request ID counter reqctr in fuse_conn
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700308 * - the sb (super_block) field in fuse_conn
Miklos Szeredi334f4852005-09-09 13:10:27 -0700309 * - the file (device file) field in fuse_conn
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700310 */
311extern spinlock_t fuse_lock;
312
313/**
Miklos Szeredie5e55582005-09-09 13:10:28 -0700314 * Get a filled in inode
315 */
316struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
Miklos Szeredi9e6268d2005-09-09 13:10:29 -0700317 int generation, struct fuse_attr *attr);
Miklos Szeredie5e55582005-09-09 13:10:28 -0700318
319/**
320 * Send FORGET command
321 */
322void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
Miklos Szeredi9e6268d2005-09-09 13:10:29 -0700323 unsigned long nodeid, u64 nlookup);
Miklos Szeredie5e55582005-09-09 13:10:28 -0700324
325/**
Miklos Szeredi04730fe2005-09-09 13:10:36 -0700326 * Send READ or READDIR request
327 */
328size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
329 struct inode *inode, loff_t pos, size_t count,
330 int isdir);
331
332/**
333 * Send OPEN or OPENDIR request
334 */
335int fuse_open_common(struct inode *inode, struct file *file, int isdir);
336
337/**
338 * Send RELEASE or RELEASEDIR request
339 */
340int fuse_release_common(struct inode *inode, struct file *file, int isdir);
341
342/**
Miklos Szeredib6aeade2005-09-09 13:10:30 -0700343 * Initialise file operations on a regular file
344 */
345void fuse_init_file_inode(struct inode *inode);
346
347/**
Miklos Szeredie5e55582005-09-09 13:10:28 -0700348 * Initialise inode operations on regular files and special files
349 */
350void fuse_init_common(struct inode *inode);
351
352/**
353 * Initialise inode and file operations on a directory
354 */
355void fuse_init_dir(struct inode *inode);
356
357/**
358 * Initialise inode operations on a symlink
359 */
360void fuse_init_symlink(struct inode *inode);
361
362/**
363 * Change attributes of an inode
364 */
365void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
366
367/**
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700368 * Check if the connection can be released, and if yes, then free the
369 * connection structure
370 */
371void fuse_release_conn(struct fuse_conn *fc);
372
Miklos Szeredi334f4852005-09-09 13:10:27 -0700373/**
374 * Initialize the client device
375 */
376int fuse_dev_init(void);
377
378/**
379 * Cleanup the client device
380 */
381void fuse_dev_cleanup(void);
382
383/**
384 * Allocate a request
385 */
386struct fuse_req *fuse_request_alloc(void);
387
388/**
389 * Free a request
390 */
391void fuse_request_free(struct fuse_req *req);
392
393/**
394 * Reinitialize a request, the preallocated flag is left unmodified
395 */
396void fuse_reset_request(struct fuse_req *req);
397
398/**
399 * Reserve a preallocated request
400 */
401struct fuse_req *fuse_get_request(struct fuse_conn *fc);
402
403/**
404 * Reserve a preallocated request, only interruptible by SIGKILL
405 */
406struct fuse_req *fuse_get_request_nonint(struct fuse_conn *fc);
407
408/**
409 * Decrement reference count of a request. If count goes to zero put
410 * on unused list (preallocated) or free reqest (not preallocated).
411 */
412void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
413
414/**
415 * Send a request (synchronous, interruptible)
416 */
417void request_send(struct fuse_conn *fc, struct fuse_req *req);
418
419/**
420 * Send a request (synchronous, non-interruptible except by SIGKILL)
421 */
422void request_send_nonint(struct fuse_conn *fc, struct fuse_req *req);
423
424/**
425 * Send a request with no reply
426 */
427void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
428
429/**
430 * Send a request in the background
431 */
432void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
433
434/**
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700435 * Release inodes and file assiciated with background request
436 */
437void fuse_release_background(struct fuse_req *req);
438
439/**
Miklos Szeredie5e55582005-09-09 13:10:28 -0700440 * Get the attributes of a file
441 */
442int fuse_do_getattr(struct inode *inode);
443
444/**
445 * Invalidate inode attributes
446 */
447void fuse_invalidate_attr(struct inode *inode);
448
449/**
Miklos Szeredi334f4852005-09-09 13:10:27 -0700450 * Send the INIT message
451 */
452void fuse_send_init(struct fuse_conn *fc);