1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 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 #ifndef _FS_FUSE_I_H
10 #define _FS_FUSE_I_H
11
12 #include <linux/fuse.h>
13 #include <linux/fs.h>
14 #include <linux/mount.h>
15 #include <linux/wait.h>
16 #include <linux/list.h>
17 #include <linux/spinlock.h>
18 #include <linux/mm.h>
19 #include <linux/backing-dev.h>
20 #include <linux/mutex.h>
21 #include <linux/rwsem.h>
22 #include <linux/rbtree.h>
23 #include <linux/poll.h>
24 #include <linux/workqueue.h>
25
26 /** Max number of pages that can be used in a single read request */
27 #define FUSE_MAX_PAGES_PER_REQ 32
28
29 /** Bias for fi->writectr, meaning new writepages must not be sent */
30 #define FUSE_NOWRITE INT_MIN
31
32 /** It could be as large as PATH_MAX, but would that have any uses? */
33 #define FUSE_NAME_MAX 1024
34
35 /** Number of dentries for each connection in the control filesystem */
36 #define FUSE_CTL_NUM_DENTRIES 5
37
38 /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem
39 module will check permissions based on the file mode. Otherwise no
40 permission checking is done in the kernel */
41 #define FUSE_DEFAULT_PERMISSIONS (1 << 0)
42
43 /** If the FUSE_ALLOW_OTHER flag is given, then not only the user
44 doing the mount will be allowed to access the filesystem */
45 #define FUSE_ALLOW_OTHER (1 << 1)
46
47 /** List of active connections */
48 extern struct list_head fuse_conn_list;
49
50 /** Global mutex protecting fuse_conn_list and the control filesystem */
51 extern struct mutex fuse_mutex;
52
53 /** Module parameters */
54 extern unsigned max_user_bgreq;
55 extern unsigned max_user_congthresh;
56
57 /* One forget request */
58 struct fuse_forget_link {
59 struct fuse_forget_one forget_one;
60 struct fuse_forget_link *next;
61 };
62
63 /** FUSE inode */
64 struct fuse_inode {
65 /** Inode data */
66 struct inode inode;
67
68 /** Unique ID, which identifies the inode between userspace
69 * and kernel */
70 u64 nodeid;
71
72 /** Number of lookups on this inode */
73 u64 nlookup;
74
75 /** The request used for sending the FORGET message */
76 struct fuse_forget_link *forget;
77
78 /** Time in jiffies until the file attributes are valid */
79 u64 i_time;
80
81 /** The sticky bit in inode->i_mode may have been removed, so
82 preserve the original mode */
83 mode_t orig_i_mode;
84
85 /** Version of last attribute change */
86 u64 attr_version;
87
88 /** Files usable in writepage. Protected by fc->lock */
89 struct list_head write_files;
90
91 /** Writepages pending on truncate or fsync */
92 struct list_head queued_writes;
93
94 /** Number of sent writes, a negative bias (FUSE_NOWRITE)
95 * means more writes are blocked */
96 int writectr;
97
98 /** Waitq for writepage completion */
99 wait_queue_head_t page_waitq;
100
101 /** List of writepage requestst (pending or sent) */
102 struct list_head writepages;
103 };
104
105 struct fuse_conn;
106
107 /** FUSE specific file data */
108 struct fuse_file {
109 /** Fuse connection for this file */
110 struct fuse_conn *fc;
111
112 /** Request reserved for flush and release */
113 struct fuse_req *reserved_req;
114
115 /** Kernel file handle guaranteed to be unique */
116 u64 kh;
117
118 /** File handle used by userspace */
119 u64 fh;
120
121 /** Node id of this file */
122 u64 nodeid;
123
124 /** Refcount */
125 atomic_t count;
126
127 /** FOPEN_* flags returned by open */
128 u32 open_flags;
129
130 /** Entry on inode's write_files list */
131 struct list_head write_entry;
132
133 /** RB node to be linked on fuse_conn->polled_files */
134 struct rb_node polled_node;
135
136 /** Wait queue head for poll */
137 wait_queue_head_t poll_wait;
138 };
139
140 /** One input argument of a request */
141 struct fuse_in_arg {
142 unsigned size;
143 const void *value;
144 };
145
146 /** The request input */
147 struct fuse_in {
148 /** The request header */
149 struct fuse_in_header h;
150
151 /** True if the data for the last argument is in req->pages */
152 unsigned argpages:1;
153
154 /** Number of arguments */
155 unsigned numargs;
156
157 /** Array of arguments */
158 struct fuse_in_arg args[3];
159 };
160
161 /** One output argument of a request */
162 struct fuse_arg {
163 unsigned size;
164 void *value;
165 };
166
167 /** The request output */
168 struct fuse_out {
169 /** Header returned from userspace */
170 struct fuse_out_header h;
171
172 /*
173 * The following bitfields are not changed during the request
174 * processing
175 */
176
177 /** Last argument is variable length (can be shorter than
178 arg->size) */
179 unsigned argvar:1;
180
181 /** Last argument is a list of pages to copy data to */
182 unsigned argpages:1;
183
184 /** Zero partially or not copied pages */
185 unsigned page_zeroing:1;
186
187 /** Pages may be replaced with new ones */
188 unsigned page_replace:1;
189
190 /** Number or arguments */
191 unsigned numargs;
192
193 /** Array of arguments */
194 struct fuse_arg args[3];
195 };
196
197 /** The request state */
198 enum fuse_req_state {
199 FUSE_REQ_INIT = 0,
200 FUSE_REQ_PENDING,
201 FUSE_REQ_READING,
202 FUSE_REQ_SENT,
203 FUSE_REQ_WRITING,
204 FUSE_REQ_FINISHED
205 };
206
207 /**
208 * A request to the client
209 */
210 struct fuse_req {
211 /** This can be on either pending processing or io lists in
212 fuse_conn */
213 struct list_head list;
214
215 /** Entry on the interrupts list */
216 struct list_head intr_entry;
217
218 /** refcount */
219 atomic_t count;
220
221 /** Unique ID for the interrupt request */
222 u64 intr_unique;
223
224 /*
225 * The following bitfields are either set once before the
226 * request is queued or setting/clearing them is protected by
227 * fuse_conn->lock
228 */
229
230 /** True if the request has reply */
231 unsigned isreply:1;
232
233 /** Force sending of the request even if interrupted */
234 unsigned force:1;
235
236 /** The request was aborted */
237 unsigned aborted:1;
238
239 /** Request is sent in the background */
240 unsigned background:1;
241
242 /** The request has been interrupted */
243 unsigned interrupted:1;
244
245 /** Data is being copied to/from the request */
246 unsigned locked:1;
247
248 /** Request is counted as "waiting" */
249 unsigned waiting:1;
250
251 /** State of the request */
252 enum fuse_req_state state;
253
254 /** The request input */
255 struct fuse_in in;
256
257 /** The request output */
258 struct fuse_out out;
259
260 /** Used to wake up the task waiting for completion of request*/
261 wait_queue_head_t waitq;
262
263 /** Data for asynchronous requests */
264 union {
265 struct {
266 union {
267 struct fuse_release_in in;
268 struct work_struct work;
269 };
270 struct path path;
271 } release;
272 struct fuse_init_in init_in;
273 struct fuse_init_out init_out;
274 struct cuse_init_in cuse_init_in;
275 struct {
276 struct fuse_read_in in;
277 u64 attr_ver;
278 } read;
279 struct {
280 struct fuse_write_in in;
281 struct fuse_write_out out;
282 } write;
283 struct fuse_notify_retrieve_in retrieve_in;
284 struct fuse_lk_in lk_in;
285 } misc;
286
287 /** page vector */
288 struct page *pages[FUSE_MAX_PAGES_PER_REQ];
289
290 /** number of pages in vector */
291 unsigned num_pages;
292
293 /** offset of data on first page */
294 unsigned page_offset;
295
296 /** File used in the request (or NULL) */
297 struct fuse_file *ff;
298
299 /** Inode used in the request or NULL */
300 struct inode *inode;
301
302 /** Link on fi->writepages */
303 struct list_head writepages_entry;
304
305 /** Request completion callback */
306 void (*end)(struct fuse_conn *, struct fuse_req *);
307
308 /** Request is stolen from fuse_file->reserved_req */
309 struct file *stolen_file;
310 };
311
312 /**
313 * A Fuse connection.
314 *
315 * This structure is created, when the filesystem is mounted, and is
316 * destroyed, when the client device is closed and the filesystem is
317 * unmounted.
318 */
319 struct fuse_conn {
320 /** Lock protecting accessess to members of this structure */
321 spinlock_t lock;
322
323 /** Mutex protecting against directory alias creation */
324 struct mutex inst_mutex;
325
326 /** Refcount */
327 atomic_t count;
328
329 /** The user id for this mount */
330 uid_t user_id;
331
332 /** The group id for this mount */
333 gid_t group_id;
334
335 /** The fuse mount flags for this mount */
336 unsigned flags;
337
338 /** Maximum read size */
339 unsigned max_read;
340
341 /** Maximum write size */
342 unsigned max_write;
343
344 /** Readers of the connection are waiting on this */
345 wait_queue_head_t waitq;
346
347 /** The list of pending requests */
348 struct list_head pending;
349
350 /** The list of requests being processed */
351 struct list_head processing;
352
353 /** The list of requests under I/O */
354 struct list_head io;
355
356 /** The next unique kernel file handle */
357 u64 khctr;
358
359 /** rbtree of fuse_files waiting for poll events indexed by ph */
360 struct rb_root polled_files;
361
362 /** Maximum number of outstanding background requests */
363 unsigned max_background;
364
365 /** Number of background requests at which congestion starts */
366 unsigned congestion_threshold;
367
368 /** Number of requests currently in the background */
369 unsigned num_background;
370
371 /** Number of background requests currently queued for userspace */
372 unsigned active_background;
373
374 /** The list of background requests set aside for later queuing */
375 struct list_head bg_queue;
376
377 /** Pending interrupts */
378 struct list_head interrupts;
379
380 /** Queue of pending forgets */
381 struct fuse_forget_link forget_list_head;
382 struct fuse_forget_link *forget_list_tail;
383
384 /** Batching of FORGET requests (positive indicates FORGET batch) */
385 int forget_batch;
386
387 /** Flag indicating if connection is blocked. This will be
388 the case before the INIT reply is received, and if there
389 are too many outstading backgrounds requests */
390 int blocked;
391
392 /** waitq for blocked connection */
393 wait_queue_head_t blocked_waitq;
394
395 /** waitq for reserved requests */
396 wait_queue_head_t reserved_req_waitq;
397
398 /** The next unique request id */
399 u64 reqctr;
400
401 /** Connection established, cleared on umount, connection
402 abort and device release */
403 unsigned connected;
404
405 /** Connection failed (version mismatch). Cannot race with
406 setting other bitfields since it is only set once in INIT
407 reply, before any other request, and never cleared */
408 unsigned conn_error:1;
409
410 /** Connection successful. Only set in INIT */
411 unsigned conn_init:1;
412
413 /** Do readpages asynchronously? Only set in INIT */
414 unsigned async_read:1;
415
416 /** Do not send separate SETATTR request before open(O_TRUNC) */
417 unsigned atomic_o_trunc:1;
418
419 /** Filesystem supports NFS exporting. Only set in INIT */
420 unsigned export_support:1;
421
422 /** Set if bdi is valid */
423 unsigned bdi_initialized:1;
424
425 /*
426 * The following bitfields are only for optimization purposes
427 * and hence races in setting them will not cause malfunction
428 */
429
430 /** Is fsync not implemented by fs? */
431 unsigned no_fsync:1;
432
433 /** Is fsyncdir not implemented by fs? */
434 unsigned no_fsyncdir:1;
435
436 /** Is flush not implemented by fs? */
437 unsigned no_flush:1;
438
439 /** Is setxattr not implemented by fs? */
440 unsigned no_setxattr:1;
441
442 /** Is getxattr not implemented by fs? */
443 unsigned no_getxattr:1;
444
445 /** Is listxattr not implemented by fs? */
446 unsigned no_listxattr:1;
447
448 /** Is removexattr not implemented by fs? */
449 unsigned no_removexattr:1;
450
451 /** Are file locking primitives not implemented by fs? */
452 unsigned no_lock:1;
453
454 /** Is access not implemented by fs? */
455 unsigned no_access:1;
456
457 /** Is create not implemented by fs? */
458 unsigned no_create:1;
459
460 /** Is interrupt not implemented by fs? */
461 unsigned no_interrupt:1;
462
463 /** Is bmap not implemented by fs? */
464 unsigned no_bmap:1;
465
466 /** Is poll not implemented by fs? */
467 unsigned no_poll:1;
468
469 /** Do multi-page cached writes */
470 unsigned big_writes:1;
471
472 /** Don't apply umask to creation modes */
473 unsigned dont_mask:1;
474
475 /** The number of requests waiting for completion */
476 atomic_t num_waiting;
477
478 /** Negotiated minor version */
479 unsigned minor;
480
481 /** Backing dev info */
482 struct backing_dev_info bdi;
483
484 /** Entry on the fuse_conn_list */
485 struct list_head entry;
486
487 /** Device ID from super block */
488 dev_t dev;
489
490 /** Dentries in the control filesystem */
491 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
492
493 /** number of dentries used in the above array */
494 int ctl_ndents;
495
496 /** O_ASYNC requests */
497 struct fasync_struct *fasync;
498
499 /** Key for lock owner ID scrambling */
500 u32 scramble_key[4];
501
502 /** Reserved request for the DESTROY message */
503 struct fuse_req *destroy_req;
504
505 /** Version counter for attribute changes */
506 u64 attr_version;
507
508 /** Called on final put */
509 void (*release)(struct fuse_conn *);
510
511 /** Super block for this connection. */
512 struct super_block *sb;
513
514 /** Read/write semaphore to hold when accessing sb. */
515 struct rw_semaphore killsb;
516 };
517
get_fuse_conn_super(struct super_block * sb)518 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
519 {
520 return sb->s_fs_info;
521 }
522
get_fuse_conn(struct inode * inode)523 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
524 {
525 return get_fuse_conn_super(inode->i_sb);
526 }
527
get_fuse_inode(struct inode * inode)528 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
529 {
530 return container_of(inode, struct fuse_inode, inode);
531 }
532
get_node_id(struct inode * inode)533 static inline u64 get_node_id(struct inode *inode)
534 {
535 return get_fuse_inode(inode)->nodeid;
536 }
537
538 /** Device operations */
539 extern const struct file_operations fuse_dev_operations;
540
541 extern const struct dentry_operations fuse_dentry_operations;
542
543 /**
544 * Inode to nodeid comparison.
545 */
546 int fuse_inode_eq(struct inode *inode, void *_nodeidp);
547
548 /**
549 * Get a filled in inode
550 */
551 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
552 int generation, struct fuse_attr *attr,
553 u64 attr_valid, u64 attr_version);
554
555 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
556 struct fuse_entry_out *outarg, struct inode **inode);
557
558 /**
559 * Send FORGET command
560 */
561 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
562 u64 nodeid, u64 nlookup);
563
564 struct fuse_forget_link *fuse_alloc_forget(void);
565
566 /**
567 * Initialize READ or READDIR request
568 */
569 void fuse_read_fill(struct fuse_req *req, struct file *file,
570 loff_t pos, size_t count, int opcode);
571
572 /**
573 * Send OPEN or OPENDIR request
574 */
575 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
576
577 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
578 struct fuse_file *fuse_file_get(struct fuse_file *ff);
579 void fuse_file_free(struct fuse_file *ff);
580 void fuse_finish_open(struct inode *inode, struct file *file);
581
582 void fuse_sync_release(struct fuse_file *ff, int flags);
583
584 /**
585 * Send RELEASE or RELEASEDIR request
586 */
587 void fuse_release_common(struct file *file, int opcode);
588
589 /**
590 * Send FSYNC or FSYNCDIR request
591 */
592 int fuse_fsync_common(struct file *file, int datasync, int isdir);
593
594 /**
595 * Notify poll wakeup
596 */
597 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
598 struct fuse_notify_poll_wakeup_out *outarg);
599
600 /**
601 * Initialize file operations on a regular file
602 */
603 void fuse_init_file_inode(struct inode *inode);
604
605 /**
606 * Initialize inode operations on regular files and special files
607 */
608 void fuse_init_common(struct inode *inode);
609
610 /**
611 * Initialize inode and file operations on a directory
612 */
613 void fuse_init_dir(struct inode *inode);
614
615 /**
616 * Initialize inode operations on a symlink
617 */
618 void fuse_init_symlink(struct inode *inode);
619
620 /**
621 * Change attributes of an inode
622 */
623 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
624 u64 attr_valid, u64 attr_version);
625
626 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
627 u64 attr_valid);
628
629 /**
630 * Initialize the client device
631 */
632 int fuse_dev_init(void);
633
634 /**
635 * Cleanup the client device
636 */
637 void fuse_dev_cleanup(void);
638
639 int fuse_ctl_init(void);
640 void fuse_ctl_cleanup(void);
641
642 /**
643 * Allocate a request
644 */
645 struct fuse_req *fuse_request_alloc(void);
646
647 struct fuse_req *fuse_request_alloc_nofs(void);
648
649 /**
650 * Free a request
651 */
652 void fuse_request_free(struct fuse_req *req);
653
654 /**
655 * Get a request, may fail with -ENOMEM
656 */
657 struct fuse_req *fuse_get_req(struct fuse_conn *fc);
658
659 /**
660 * Gets a requests for a file operation, always succeeds
661 */
662 struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file);
663
664 /**
665 * Decrement reference count of a request. If count goes to zero free
666 * the request.
667 */
668 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
669
670 /**
671 * Send a request (synchronous)
672 */
673 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req);
674
675 /**
676 * Send a request in the background
677 */
678 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req);
679
680 void fuse_request_send_background_locked(struct fuse_conn *fc,
681 struct fuse_req *req);
682
683 /* Abort all requests */
684 void fuse_abort_conn(struct fuse_conn *fc);
685
686 /**
687 * Invalidate inode attributes
688 */
689 void fuse_invalidate_attr(struct inode *inode);
690
691 void fuse_invalidate_entry_cache(struct dentry *entry);
692
693 /**
694 * Acquire reference to fuse_conn
695 */
696 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
697
698 void fuse_conn_kill(struct fuse_conn *fc);
699
700 /**
701 * Initialize fuse_conn
702 */
703 void fuse_conn_init(struct fuse_conn *fc);
704
705 /**
706 * Release reference to fuse_conn
707 */
708 void fuse_conn_put(struct fuse_conn *fc);
709
710 /**
711 * Add connection to control filesystem
712 */
713 int fuse_ctl_add_conn(struct fuse_conn *fc);
714
715 /**
716 * Remove connection from control filesystem
717 */
718 void fuse_ctl_remove_conn(struct fuse_conn *fc);
719
720 /**
721 * Is file type valid?
722 */
723 int fuse_valid_type(int m);
724
725 /**
726 * Is task allowed to perform filesystem operation?
727 */
728 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task);
729
730 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
731
732 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
733 struct file *file, bool *refreshed);
734
735 void fuse_flush_writepages(struct inode *inode);
736
737 void fuse_set_nowrite(struct inode *inode);
738 void fuse_release_nowrite(struct inode *inode);
739
740 u64 fuse_get_attr_version(struct fuse_conn *fc);
741
742 /**
743 * File-system tells the kernel to invalidate cache for the given node id.
744 */
745 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
746 loff_t offset, loff_t len);
747
748 /**
749 * File-system tells the kernel to invalidate parent attributes and
750 * the dentry matching parent/name.
751 */
752 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
753 struct qstr *name);
754
755 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
756 bool isdir);
757 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
758 size_t count, loff_t *ppos, int write);
759 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
760 unsigned int flags);
761 unsigned fuse_file_poll(struct file *file, poll_table *wait);
762 int fuse_dev_release(struct inode *inode, struct file *file);
763
764 void fuse_write_update_size(struct inode *inode, loff_t pos);
765
766 #endif /* _FS_FUSE_I_H */
767