fuse_i.h 12.5 KB
Newer Older
Miklos Szeredi's avatar
Miklos Szeredi committed
1
2
/*
  FUSE: Filesystem in Userspace
3
  Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>
Miklos Szeredi's avatar
Miklos Szeredi committed
4
5
6
7
8
9
10

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include <linux/fuse.h>
#include <linux/fs.h>
11
#include <linux/mount.h>
Miklos Szeredi's avatar
Miklos Szeredi committed
12
13
14
15
16
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/backing-dev.h>
17
#include <linux/mutex.h>
Miklos Szeredi's avatar
Miklos Szeredi committed
18

19
20
21
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32

22
/** Maximum number of outstanding background requests */
23
24
25
26
#define FUSE_MAX_BACKGROUND 12

/** Congestion starts at 75% of maximum */
#define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
27

28
29
30
/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024

31
32
33
/** Number of dentries for each connection in the control filesystem */
#define FUSE_CTL_NUM_DENTRIES 3

Miklos Szeredi's avatar
Miklos Szeredi committed
34
35
36
37
38
39
40
41
42
/** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
    module will check permissions based on the file mode.  Otherwise no
    permission checking is done in the kernel */
#define FUSE_DEFAULT_PERMISSIONS (1 << 0)

/** If the FUSE_ALLOW_OTHER flag is given, then not only the user
    doing the mount will be allowed to access the filesystem */
#define FUSE_ALLOW_OTHER         (1 << 1)

43
44
45
46
47
/** List of active connections */
extern struct list_head fuse_conn_list;

/** Global mutex protecting fuse_conn_list and the control filesystem */
extern struct mutex fuse_mutex;
Miklos Szeredi's avatar
Miklos Szeredi committed
48

Miklos Szeredi's avatar
Miklos Szeredi committed
49
50
51
52
53
54
55
56
57
/** FUSE inode */
struct fuse_inode {
	/** Inode data */
	struct inode inode;

	/** Unique ID, which identifies the inode between userspace
	 * and kernel */
	u64 nodeid;

58
59
60
	/** Number of lookups on this inode */
	u64 nlookup;

61
62
63
	/** The request used for sending the FORGET message */
	struct fuse_req *forget_req;

Miklos Szeredi's avatar
Miklos Szeredi committed
64
	/** Time in jiffies until the file attributes are valid */
Miklos Szeredi's avatar
Miklos Szeredi committed
65
	u64 i_time;
Miklos Szeredi's avatar
Miklos Szeredi committed
66
67
};

68
69
70
/** FUSE specific file data */
struct fuse_file {
	/** Request reserved for flush and release */
71
	struct fuse_req *reserved_req;
72
73
74

	/** File handle used by userspace */
	u64 fh;
75
76
77

	/** Refcount */
	atomic_t count;
78
79
};

80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
/** One input argument of a request */
struct fuse_in_arg {
	unsigned size;
	const void *value;
};

/** The request input */
struct fuse_in {
	/** The request header */
	struct fuse_in_header h;

	/** True if the data for the last argument is in req->pages */
	unsigned argpages:1;

	/** Number of arguments */
	unsigned numargs;

	/** Array of arguments */
	struct fuse_in_arg args[3];
};

/** One output argument of a request */
struct fuse_arg {
	unsigned size;
	void *value;
};

/** The request output */
struct fuse_out {
	/** Header returned from userspace */
	struct fuse_out_header h;

112
113
114
115
116
	/*
	 * The following bitfields are not changed during the request
	 * processing
	 */

117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
	/** Last argument is variable length (can be shorter than
	    arg->size) */
	unsigned argvar:1;

	/** Last argument is a list of pages to copy data to */
	unsigned argpages:1;

	/** Zero partially or not copied pages */
	unsigned page_zeroing:1;

	/** Number or arguments */
	unsigned numargs;

	/** Array of arguments */
	struct fuse_arg args[3];
};

134
135
136
137
138
139
/** The request state */
enum fuse_req_state {
	FUSE_REQ_INIT = 0,
	FUSE_REQ_PENDING,
	FUSE_REQ_READING,
	FUSE_REQ_SENT,
140
	FUSE_REQ_WRITING,
141
142
143
	FUSE_REQ_FINISHED
};

144
145
struct fuse_conn;

146
147
148
149
/**
 * A request to the client
 */
struct fuse_req {
150
151
	/** This can be on either pending processing or io lists in
	    fuse_conn */
152
153
	struct list_head list;

154
155
156
	/** Entry on the interrupts list  */
	struct list_head intr_entry;

157
158
159
	/** refcount */
	atomic_t count;

160
161
162
	/** Unique ID for the interrupt request */
	u64 intr_unique;

163
164
165
	/*
	 * The following bitfields are either set once before the
	 * request is queued or setting/clearing them is protected by
166
	 * fuse_conn->lock
167
168
	 */

169
170
171
	/** True if the request has reply */
	unsigned isreply:1;

172
173
174
	/** Force sending of the request even if interrupted */
	unsigned force:1;

175
176
	/** The request was aborted */
	unsigned aborted:1;
177
178
179
180

	/** Request is sent in the background */
	unsigned background:1;

181
182
183
	/** The request has been interrupted */
	unsigned interrupted:1;

184
185
186
	/** Data is being copied to/from the request */
	unsigned locked:1;

187
188
189
	/** Request is counted as "waiting" */
	unsigned waiting:1;

190
191
	/** State of the request */
	enum fuse_req_state state;
192
193
194
195
196
197
198
199
200
201
202
203

	/** The request input */
	struct fuse_in in;

	/** The request output */
	struct fuse_out out;

	/** Used to wake up the task waiting for completion of request*/
	wait_queue_head_t waitq;

	/** Data for asynchronous requests */
	union {
204
		struct fuse_forget_in forget_in;
205
		struct fuse_release_in release_in;
206
207
		struct fuse_init_in init_in;
		struct fuse_init_out init_out;
208
		struct fuse_read_in read_in;
209
		struct fuse_lk_in lk_in;
210
211
212
213
214
215
216
217
218
219
220
221
	} misc;

	/** page vector */
	struct page *pages[FUSE_MAX_PAGES_PER_REQ];

	/** number of pages in vector */
	unsigned num_pages;

	/** offset of data on first page */
	unsigned page_offset;

	/** File used in the request (or NULL) */
222
	struct fuse_file *ff;
223

224
225
226
227
228
229
	/** vfsmount used in release */
	struct vfsmount *vfsmount;

	/** dentry used in release */
	struct dentry *dentry;

230
231
	/** Request completion callback */
	void (*end)(struct fuse_conn *, struct fuse_req *);
232
233
234

	/** Request is stolen from fuse_file->reserved_req */
	struct file *stolen_file;
235
236
};

Miklos Szeredi's avatar
Miklos Szeredi committed
237
238
239
240
241
242
243
244
/**
 * A Fuse connection.
 *
 * This structure is created, when the filesystem is mounted, and is
 * destroyed, when the client device is closed and the filesystem is
 * unmounted.
 */
struct fuse_conn {
245
246
247
	/** Lock protecting accessess to  members of this structure */
	spinlock_t lock;

248
249
250
	/** Mutex protecting against directory alias creation */
	struct mutex inst_mutex;

251
252
253
	/** Refcount */
	atomic_t count;

Miklos Szeredi's avatar
Miklos Szeredi committed
254
255
256
	/** The user id for this mount */
	uid_t user_id;

257
258
259
	/** The group id for this mount */
	gid_t group_id;

Miklos Szeredi's avatar
Miklos Szeredi committed
260
261
262
	/** The fuse mount flags for this mount */
	unsigned flags;

263
264
265
	/** Maximum read size */
	unsigned max_read;

Miklos Szeredi's avatar
Miklos Szeredi committed
266
267
268
	/** Maximum write size */
	unsigned max_write;

269
270
271
272
273
274
275
276
277
	/** Readers of the connection are waiting on this */
	wait_queue_head_t waitq;

	/** The list of pending requests */
	struct list_head pending;

	/** The list of requests being processed */
	struct list_head processing;

278
279
280
	/** The list of requests under I/O */
	struct list_head io;

281
282
283
	/** Number of requests currently in the background */
	unsigned num_background;

284
285
286
	/** Pending interrupts */
	struct list_head interrupts;

287
288
289
290
291
292
293
	/** Flag indicating if connection is blocked.  This will be
	    the case before the INIT reply is received, and if there
	    are too many outstading backgrounds requests */
	int blocked;

	/** waitq for blocked connection */
	wait_queue_head_t blocked_waitq;
294
295
296

	/** waitq for reserved requests */
	wait_queue_head_t reserved_req_waitq;
297

298
299
300
	/** The next unique request id */
	u64 reqctr;

301
302
	/** Connection established, cleared on umount, connection
	    abort and device release */
303
	unsigned connected;
Miklos Szeredi's avatar
Miklos Szeredi committed
304

305
306
307
	/** Connection failed (version mismatch).  Cannot race with
	    setting other bitfields since it is only set once in INIT
	    reply, before any other request, and never cleared */
308
309
	unsigned conn_error : 1;

310
311
312
	/** Connection successful.  Only set in INIT */
	unsigned conn_init : 1;

313
314
315
	/** Do readpages asynchronously?  Only set in INIT */
	unsigned async_read : 1;

316
317
318
319
320
	/*
	 * The following bitfields are only for optimization purposes
	 * and hence races in setting them will not cause malfunction
	 */

321
322
323
	/** Is fsync not implemented by fs? */
	unsigned no_fsync : 1;

324
325
326
	/** Is fsyncdir not implemented by fs? */
	unsigned no_fsyncdir : 1;

327
328
329
	/** Is flush not implemented by fs? */
	unsigned no_flush : 1;

330
331
332
333
334
335
336
337
338
339
340
341
	/** Is setxattr not implemented by fs? */
	unsigned no_setxattr : 1;

	/** Is getxattr not implemented by fs? */
	unsigned no_getxattr : 1;

	/** Is listxattr not implemented by fs? */
	unsigned no_listxattr : 1;

	/** Is removexattr not implemented by fs? */
	unsigned no_removexattr : 1;

342
343
344
	/** Are file locking primitives not implemented by fs? */
	unsigned no_lock : 1;

Miklos Szeredi's avatar
Miklos Szeredi committed
345
346
347
	/** Is access not implemented by fs? */
	unsigned no_access : 1;

348
349
350
	/** Is create not implemented by fs? */
	unsigned no_create : 1;

351
352
353
	/** Is interrupt not implemented by fs? */
	unsigned no_interrupt : 1;

354
355
356
	/** Is bmap not implemented by fs? */
	unsigned no_bmap : 1;

357
358
359
	/** The number of requests waiting for completion */
	atomic_t num_waiting;

360
361
362
	/** Negotiated minor version */
	unsigned minor;

Miklos Szeredi's avatar
Miklos Szeredi committed
363
364
	/** Backing dev info */
	struct backing_dev_info bdi;
365

366
367
368
369
370
371
372
373
374
375
376
	/** Entry on the fuse_conn_list */
	struct list_head entry;

	/** Unique ID */
	u64 id;

	/** Dentries in the control filesystem */
	struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];

	/** number of dentries used in the above array */
	int ctl_ndents;
377
378
379

	/** O_ASYNC requests */
	struct fasync_struct *fasync;
380
381
382

	/** Key for lock owner ID scrambling */
	u32 scramble_key[4];
383
384
385

	/** Reserved request for the DESTROY message */
	struct fuse_req *destroy_req;
Miklos Szeredi's avatar
Miklos Szeredi committed
386
387
388
389
};

static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
{
390
	return sb->s_fs_info;
Miklos Szeredi's avatar
Miklos Szeredi committed
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
}

static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
{
	return get_fuse_conn_super(inode->i_sb);
}

static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
{
	return container_of(inode, struct fuse_inode, inode);
}

static inline u64 get_node_id(struct inode *inode)
{
	return get_fuse_inode(inode)->nodeid;
}

408
/** Device operations */
409
extern const struct file_operations fuse_dev_operations;
410

411
412
413
414
/**
 * Get a filled in inode
 */
struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
415
			int generation, struct fuse_attr *attr);
416
417
418
419
420

/**
 * Send FORGET command
 */
void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
421
		      unsigned long nodeid, u64 nlookup);
422

423
/**
424
 * Initialize READ or READDIR request
425
 */
426
void fuse_read_fill(struct fuse_req *req, struct fuse_file *ff,
427
		    struct inode *inode, loff_t pos, size_t count, int opcode);
428
429
430
431
432
433

/**
 * Send OPEN or OPENDIR request
 */
int fuse_open_common(struct inode *inode, struct file *file, int isdir);

434
435
436
437
438
struct fuse_file *fuse_file_alloc(void);
void fuse_file_free(struct fuse_file *ff);
void fuse_finish_open(struct inode *inode, struct file *file,
		      struct fuse_file *ff, struct fuse_open_out *outarg);

439
440
441
/** Fill in ff->reserved_req with a RELEASE request */
void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode);

442
443
444
445
446
/**
 * Send RELEASE or RELEASEDIR request
 */
int fuse_release_common(struct inode *inode, struct file *file, int isdir);

447
448
449
450
451
452
/**
 * Send FSYNC or FSYNCDIR request
 */
int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
		      int isdir);

453
/**
Miklos Szeredi's avatar
Miklos Szeredi committed
454
 * Initialize file operations on a regular file
455
456
457
 */
void fuse_init_file_inode(struct inode *inode);

458
/**
Miklos Szeredi's avatar
Miklos Szeredi committed
459
 * Initialize inode operations on regular files and special files
460
461
462
463
 */
void fuse_init_common(struct inode *inode);

/**
Miklos Szeredi's avatar
Miklos Szeredi committed
464
 * Initialize inode and file operations on a directory
465
466
467
468
 */
void fuse_init_dir(struct inode *inode);

/**
Miklos Szeredi's avatar
Miklos Szeredi committed
469
 * Initialize inode operations on a symlink
470
471
472
473
474
475
476
477
 */
void fuse_init_symlink(struct inode *inode);

/**
 * Change attributes of an inode
 */
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr);

478
479
480
481
482
483
484
485
486
487
/**
 * Initialize the client device
 */
int fuse_dev_init(void);

/**
 * Cleanup the client device
 */
void fuse_dev_cleanup(void);

488
489
490
int fuse_ctl_init(void);
void fuse_ctl_cleanup(void);

491
492
493
494
495
496
497
498
499
500
501
/**
 * Allocate a request
 */
struct fuse_req *fuse_request_alloc(void);

/**
 * Free a request
 */
void fuse_request_free(struct fuse_req *req);

/**
502
 * Get a request, may fail with -ENOMEM
503
 */
504
struct fuse_req *fuse_get_req(struct fuse_conn *fc);
505

506
507
508
509
510
/**
 * Gets a requests for a file operation, always succeeds
 */
struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);

511
/**
512
513
 * Decrement reference count of a request.  If count goes to zero free
 * the request.
514
515
516
517
 */
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);

/**
518
 * Send a request (synchronous)
519
520
521
522
523
524
525
526
527
528
529
530
531
 */
void request_send(struct fuse_conn *fc, struct fuse_req *req);

/**
 * Send a request with no reply
 */
void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);

/**
 * Send a request in the background
 */
void request_send_background(struct fuse_conn *fc, struct fuse_req *req);

532
/* Abort all requests */
533
534
void fuse_abort_conn(struct fuse_conn *fc);

535
536
537
538
/**
 * Invalidate inode attributes
 */
void fuse_invalidate_attr(struct inode *inode);
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558

/**
 * Acquire reference to fuse_conn
 */
struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);

/**
 * Release reference to fuse_conn
 */
void fuse_conn_put(struct fuse_conn *fc);

/**
 * Add connection to control filesystem
 */
int fuse_ctl_add_conn(struct fuse_conn *fc);

/**
 * Remove connection from control filesystem
 */
void fuse_ctl_remove_conn(struct fuse_conn *fc);
559
560
561
562
563

/**
 * Is file type valid?
 */
int fuse_valid_type(int m);