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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
Miklos Szeredi82547982005-09-09 13:10:38 -0700251 /** Is fsyncdir not implemented by fs? */
252 unsigned no_fsyncdir : 1;
253
Miklos Szeredib6aeade2005-09-09 13:10:30 -0700254 /** Is flush not implemented by fs? */
255 unsigned no_flush : 1;
256
Miklos Szeredi92a87802005-09-09 13:10:31 -0700257 /** 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
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700269 /** Backing dev info */
270 struct backing_dev_info bdi;
271};
272
273static 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
278static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
279{
280 return *get_fuse_conn_super_p(sb);
281}
282
283static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
284{
285 return get_fuse_conn_super(inode->i_sb);
286}
287
288static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
289{
290 return container_of(inode, struct fuse_inode, inode);
291}
292
293static inline u64 get_node_id(struct inode *inode)
294{
295 return get_fuse_inode(inode)->nodeid;
296}
297
Miklos Szeredi334f4852005-09-09 13:10:27 -0700298/** Device operations */
299extern struct file_operations fuse_dev_operations;
300
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700301/**
302 * This is the single global spinlock which protects FUSE's structures
303 *
304 * The following data is protected by this lock:
305 *
Miklos Szeredi334f4852005-09-09 13:10:27 -0700306 * - the private_data field of the device file
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700307 * - the s_fs_info field of the super block
Miklos Szeredi334f4852005-09-09 13:10:27 -0700308 * - unused_list, pending, processing lists in fuse_conn
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700309 * - background list in fuse_conn
Miklos Szeredi334f4852005-09-09 13:10:27 -0700310 * - the unique request ID counter reqctr in fuse_conn
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700311 * - the sb (super_block) field in fuse_conn
Miklos Szeredi334f4852005-09-09 13:10:27 -0700312 * - the file (device file) field in fuse_conn
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700313 */
314extern spinlock_t fuse_lock;
315
316/**
Miklos Szeredie5e55582005-09-09 13:10:28 -0700317 * Get a filled in inode
318 */
319struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
Miklos Szeredi9e6268d2005-09-09 13:10:29 -0700320 int generation, struct fuse_attr *attr);
Miklos Szeredie5e55582005-09-09 13:10:28 -0700321
322/**
323 * Send FORGET command
324 */
325void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
Miklos Szeredi9e6268d2005-09-09 13:10:29 -0700326 unsigned long nodeid, u64 nlookup);
Miklos Szeredie5e55582005-09-09 13:10:28 -0700327
328/**
Miklos Szeredi04730fe2005-09-09 13:10:36 -0700329 * Send READ or READDIR request
330 */
331size_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 */
338int fuse_open_common(struct inode *inode, struct file *file, int isdir);
339
340/**
341 * Send RELEASE or RELEASEDIR request
342 */
343int fuse_release_common(struct inode *inode, struct file *file, int isdir);
344
345/**
Miklos Szeredi82547982005-09-09 13:10:38 -0700346 * Send FSYNC or FSYNCDIR request
347 */
348int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
349 int isdir);
350
351/**
Miklos Szeredib6aeade2005-09-09 13:10:30 -0700352 * Initialise file operations on a regular file
353 */
354void fuse_init_file_inode(struct inode *inode);
355
356/**
Miklos Szeredie5e55582005-09-09 13:10:28 -0700357 * Initialise inode operations on regular files and special files
358 */
359void fuse_init_common(struct inode *inode);
360
361/**
362 * Initialise inode and file operations on a directory
363 */
364void fuse_init_dir(struct inode *inode);
365
366/**
367 * Initialise inode operations on a symlink
368 */
369void fuse_init_symlink(struct inode *inode);
370
371/**
372 * Change attributes of an inode
373 */
374void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);
375
376/**
Miklos Szeredid8a5ba42005-09-09 13:10:26 -0700377 * Check if the connection can be released, and if yes, then free the
378 * connection structure
379 */
380void fuse_release_conn(struct fuse_conn *fc);
381
Miklos Szeredi334f4852005-09-09 13:10:27 -0700382/**
383 * Initialize the client device
384 */
385int fuse_dev_init(void);
386
387/**
388 * Cleanup the client device
389 */
390void fuse_dev_cleanup(void);
391
392/**
393 * Allocate a request
394 */
395struct fuse_req *fuse_request_alloc(void);
396
397/**
398 * Free a request
399 */
400void fuse_request_free(struct fuse_req *req);
401
402/**
403 * Reinitialize a request, the preallocated flag is left unmodified
404 */
405void fuse_reset_request(struct fuse_req *req);
406
407/**
408 * Reserve a preallocated request
409 */
410struct fuse_req *fuse_get_request(struct fuse_conn *fc);
411
412/**
Miklos Szeredi334f4852005-09-09 13:10:27 -0700413 * Decrement reference count of a request. If count goes to zero put
414 * on unused list (preallocated) or free reqest (not preallocated).
415 */
416void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
417
418/**
Miklos Szeredi7c352bd2005-09-09 13:10:39 -0700419 * Send a request (synchronous)
Miklos Szeredi334f4852005-09-09 13:10:27 -0700420 */
421void request_send(struct fuse_conn *fc, struct fuse_req *req);
422
423/**
Miklos Szeredi334f4852005-09-09 13:10:27 -0700424 * Send a request with no reply
425 */
426void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
427
428/**
429 * Send a request in the background
430 */
431void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
432
433/**
Miklos Szeredi1e9a4ed2005-09-09 13:10:31 -0700434 * Release inodes and file assiciated with background request
435 */
436void fuse_release_background(struct fuse_req *req);
437
438/**
Miklos Szeredie5e55582005-09-09 13:10:28 -0700439 * Get the attributes of a file
440 */
441int fuse_do_getattr(struct inode *inode);
442
443/**
444 * Invalidate inode attributes
445 */
446void fuse_invalidate_attr(struct inode *inode);
447
448/**
Miklos Szeredi334f4852005-09-09 13:10:27 -0700449 * Send the INIT message
450 */
451void fuse_send_init(struct fuse_conn *fc);