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 #ifndef pr_fmt
13 # define pr_fmt(fmt) "fuse: " fmt
14 #endif
15
16 #include <linux/fuse.h>
17 #include <linux/fs.h>
18 #include <linux/mount.h>
19 #include <linux/wait.h>
20 #include <linux/list.h>
21 #include <linux/spinlock.h>
22 #include <linux/mm.h>
23 #include <linux/backing-dev.h>
24 #include <linux/mutex.h>
25 #include <linux/rwsem.h>
26 #include <linux/rbtree.h>
27 #include <linux/poll.h>
28 #include <linux/workqueue.h>
29 #include <linux/kref.h>
30 #include <linux/xattr.h>
31 #include <linux/pid_namespace.h>
32 #include <linux/refcount.h>
33 #include <linux/user_namespace.h>
34
35 /** Default max number of pages that can be used in a single read request */
36 #define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32
37
38 /** Maximum of max_pages received in init_out */
39 #define FUSE_MAX_MAX_PAGES 256
40
41 /** Bias for fi->writectr, meaning new writepages must not be sent */
42 #define FUSE_NOWRITE INT_MIN
43
44 /** It could be as large as PATH_MAX, but would that have any uses? */
45 #define FUSE_NAME_MAX 1024
46
47 /** Number of dentries for each connection in the control filesystem */
48 #define FUSE_CTL_NUM_DENTRIES 5
49
50 /** List of active connections */
51 extern struct list_head fuse_conn_list;
52
53 /** Global mutex protecting fuse_conn_list and the control filesystem */
54 extern struct mutex fuse_mutex;
55
56 /** Module parameters */
57 extern unsigned max_user_bgreq;
58 extern unsigned max_user_congthresh;
59
60 /* One forget request */
61 struct fuse_forget_link {
62 struct fuse_forget_one forget_one;
63 struct fuse_forget_link *next;
64 };
65
66 /* Submount lookup tracking */
67 struct fuse_submount_lookup {
68 /** Refcount */
69 refcount_t count;
70
71 /** Unique ID, which identifies the inode between userspace
72 * and kernel */
73 u64 nodeid;
74
75 /** The request used for sending the FORGET message */
76 struct fuse_forget_link *forget;
77 };
78
79 /** Container for data related to mapping to backing file */
80 struct fuse_backing {
81 struct file *file;
82 struct cred *cred;
83
84 /** refcount */
85 refcount_t count;
86 struct rcu_head rcu;
87 };
88
89 /** FUSE inode */
90 struct fuse_inode {
91 /** Inode data */
92 struct inode inode;
93
94 /** Unique ID, which identifies the inode between userspace
95 * and kernel */
96 u64 nodeid;
97
98 /** Number of lookups on this inode */
99 u64 nlookup;
100
101 /** The request used for sending the FORGET message */
102 struct fuse_forget_link *forget;
103
104 /** Time in jiffies until the file attributes are valid */
105 u64 i_time;
106
107 /* Which attributes are invalid */
108 u32 inval_mask;
109
110 /** The sticky bit in inode->i_mode may have been removed, so
111 preserve the original mode */
112 umode_t orig_i_mode;
113
114 /* Cache birthtime */
115 struct timespec64 i_btime;
116
117 /** 64 bit inode number */
118 u64 orig_ino;
119
120 /** Version of last attribute change */
121 u64 attr_version;
122
123 union {
124 /* read/write io cache (regular file only) */
125 struct {
126 /* Files usable in writepage. Protected by fi->lock */
127 struct list_head write_files;
128
129 /* Writepages pending on truncate or fsync */
130 struct list_head queued_writes;
131
132 /* Number of sent writes, a negative bias
133 * (FUSE_NOWRITE) means more writes are blocked */
134 int writectr;
135
136 /** Number of files/maps using page cache */
137 int iocachectr;
138
139 /* Waitq for writepage completion */
140 wait_queue_head_t page_waitq;
141
142 /* waitq for direct-io completion */
143 wait_queue_head_t direct_io_waitq;
144
145 /* List of writepage requestst (pending or sent) */
146 struct rb_root writepages;
147 };
148
149 /* readdir cache (directory only) */
150 struct {
151 /* true if fully cached */
152 bool cached;
153
154 /* size of cache */
155 loff_t size;
156
157 /* position at end of cache (position of next entry) */
158 loff_t pos;
159
160 /* version of the cache */
161 u64 version;
162
163 /* modification time of directory when cache was
164 * started */
165 struct timespec64 mtime;
166
167 /* iversion of directory when cache was started */
168 u64 iversion;
169
170 /* protects above fields */
171 spinlock_t lock;
172 } rdc;
173 };
174
175 /** Miscellaneous bits describing inode state */
176 unsigned long state;
177
178 /** Lock for serializing lookup and readdir for back compatibility*/
179 struct mutex mutex;
180
181 /** Lock to protect write related fields */
182 spinlock_t lock;
183
184 #ifdef CONFIG_FUSE_DAX
185 /*
186 * Dax specific inode data
187 */
188 struct fuse_inode_dax *dax;
189 #endif
190 /** Submount specific lookup tracking */
191 struct fuse_submount_lookup *submount_lookup;
192 #ifdef CONFIG_FUSE_PASSTHROUGH
193 /** Reference to backing file in passthrough mode */
194 struct fuse_backing *fb;
195 #endif
196 };
197
198 /** FUSE inode state bits */
199 enum {
200 /** Advise readdirplus */
201 FUSE_I_ADVISE_RDPLUS,
202 /** Initialized with readdirplus */
203 FUSE_I_INIT_RDPLUS,
204 /** An operation changing file size is in progress */
205 FUSE_I_SIZE_UNSTABLE,
206 /* Bad inode */
207 FUSE_I_BAD,
208 /* Has btime */
209 FUSE_I_BTIME,
210 /* Wants or already has page cache IO */
211 FUSE_I_CACHE_IO_MODE,
212 };
213
214 struct fuse_conn;
215 struct fuse_mount;
216 union fuse_file_args;
217
218 /** FUSE specific file data */
219 struct fuse_file {
220 /** Fuse connection for this file */
221 struct fuse_mount *fm;
222
223 /* Argument space reserved for open/release */
224 union fuse_file_args *args;
225
226 /** Kernel file handle guaranteed to be unique */
227 u64 kh;
228
229 /** File handle used by userspace */
230 u64 fh;
231
232 /** Node id of this file */
233 u64 nodeid;
234
235 /** Refcount */
236 refcount_t count;
237
238 /** FOPEN_* flags returned by open */
239 u32 open_flags;
240
241 /** Entry on inode's write_files list */
242 struct list_head write_entry;
243
244 /* Readdir related */
245 struct {
246 /* Dir stream position */
247 loff_t pos;
248
249 /* Offset in cache */
250 loff_t cache_off;
251
252 /* Version of cache we are reading */
253 u64 version;
254
255 } readdir;
256
257 /** RB node to be linked on fuse_conn->polled_files */
258 struct rb_node polled_node;
259
260 /** Wait queue head for poll */
261 wait_queue_head_t poll_wait;
262
263 /** Does file hold a fi->iocachectr refcount? */
264 enum { IOM_NONE, IOM_CACHED, IOM_UNCACHED } iomode;
265
266 #ifdef CONFIG_FUSE_PASSTHROUGH
267 /** Reference to backing file in passthrough mode */
268 struct file *passthrough;
269 const struct cred *cred;
270 #endif
271
272 /** Has flock been performed on this file? */
273 bool flock:1;
274 };
275
276 /** One input argument of a request */
277 struct fuse_in_arg {
278 unsigned size;
279 const void *value;
280 };
281
282 /** One output argument of a request */
283 struct fuse_arg {
284 unsigned size;
285 void *value;
286 };
287
288 /** FUSE page descriptor */
289 struct fuse_page_desc {
290 unsigned int length;
291 unsigned int offset;
292 };
293
294 struct fuse_args {
295 uint64_t nodeid;
296 uint32_t opcode;
297 uint8_t in_numargs;
298 uint8_t out_numargs;
299 uint8_t ext_idx;
300 bool force:1;
301 bool noreply:1;
302 bool nocreds:1;
303 bool in_pages:1;
304 bool out_pages:1;
305 bool user_pages:1;
306 bool out_argvar:1;
307 bool page_zeroing:1;
308 bool page_replace:1;
309 bool may_block:1;
310 bool is_ext:1;
311 bool is_pinned:1;
312 struct fuse_in_arg in_args[3];
313 struct fuse_arg out_args[2];
314 void (*end)(struct fuse_mount *fm, struct fuse_args *args, int error);
315 };
316
317 struct fuse_args_pages {
318 struct fuse_args args;
319 struct page **pages;
320 struct fuse_page_desc *descs;
321 unsigned int num_pages;
322 };
323
324 struct fuse_release_args {
325 struct fuse_args args;
326 struct fuse_release_in inarg;
327 struct inode *inode;
328 };
329
330 union fuse_file_args {
331 /* Used during open() */
332 struct fuse_open_out open_outarg;
333 /* Used during release() */
334 struct fuse_release_args release_args;
335 };
336
337 #define FUSE_ARGS(args) struct fuse_args args = {}
338
339 /** The request IO state (for asynchronous processing) */
340 struct fuse_io_priv {
341 struct kref refcnt;
342 int async;
343 spinlock_t lock;
344 unsigned reqs;
345 ssize_t bytes;
346 size_t size;
347 __u64 offset;
348 bool write;
349 bool should_dirty;
350 int err;
351 struct kiocb *iocb;
352 struct completion *done;
353 bool blocking;
354 };
355
356 #define FUSE_IO_PRIV_SYNC(i) \
357 { \
358 .refcnt = KREF_INIT(1), \
359 .async = 0, \
360 .iocb = i, \
361 }
362
363 /**
364 * Request flags
365 *
366 * FR_ISREPLY: set if the request has reply
367 * FR_FORCE: force sending of the request even if interrupted
368 * FR_BACKGROUND: request is sent in the background
369 * FR_WAITING: request is counted as "waiting"
370 * FR_ABORTED: the request was aborted
371 * FR_INTERRUPTED: the request has been interrupted
372 * FR_LOCKED: data is being copied to/from the request
373 * FR_PENDING: request is not yet in userspace
374 * FR_SENT: request is in userspace, waiting for an answer
375 * FR_FINISHED: request is finished
376 * FR_PRIVATE: request is on private list
377 * FR_ASYNC: request is asynchronous
378 */
379 enum fuse_req_flag {
380 FR_ISREPLY,
381 FR_FORCE,
382 FR_BACKGROUND,
383 FR_WAITING,
384 FR_ABORTED,
385 FR_INTERRUPTED,
386 FR_LOCKED,
387 FR_PENDING,
388 FR_SENT,
389 FR_FINISHED,
390 FR_PRIVATE,
391 FR_ASYNC,
392 };
393
394 /**
395 * A request to the client
396 *
397 * .waitq.lock protects the following fields:
398 * - FR_ABORTED
399 * - FR_LOCKED (may also be modified under fc->lock, tested under both)
400 */
401 struct fuse_req {
402 /** This can be on either pending processing or io lists in
403 fuse_conn */
404 struct list_head list;
405
406 /** Entry on the interrupts list */
407 struct list_head intr_entry;
408
409 /* Input/output arguments */
410 struct fuse_args *args;
411
412 /** refcount */
413 refcount_t count;
414
415 /* Request flags, updated with test/set/clear_bit() */
416 unsigned long flags;
417
418 /* The request input header */
419 struct {
420 struct fuse_in_header h;
421 } in;
422
423 /* The request output header */
424 struct {
425 struct fuse_out_header h;
426 } out;
427
428 /** Used to wake up the task waiting for completion of request*/
429 wait_queue_head_t waitq;
430
431 #if IS_ENABLED(CONFIG_VIRTIO_FS)
432 /** virtio-fs's physically contiguous buffer for in and out args */
433 void *argbuf;
434 #endif
435
436 /** fuse_mount this request belongs to */
437 struct fuse_mount *fm;
438 };
439
440 struct fuse_iqueue;
441
442 /**
443 * Input queue callbacks
444 *
445 * Input queue signalling is device-specific. For example, the /dev/fuse file
446 * uses fiq->waitq and fasync to wake processes that are waiting on queue
447 * readiness. These callbacks allow other device types to respond to input
448 * queue activity.
449 */
450 struct fuse_iqueue_ops {
451 /**
452 * Signal that a forget has been queued
453 */
454 void (*wake_forget_and_unlock)(struct fuse_iqueue *fiq)
455 __releases(fiq->lock);
456
457 /**
458 * Signal that an INTERRUPT request has been queued
459 */
460 void (*wake_interrupt_and_unlock)(struct fuse_iqueue *fiq)
461 __releases(fiq->lock);
462
463 /**
464 * Signal that a request has been queued
465 */
466 void (*wake_pending_and_unlock)(struct fuse_iqueue *fiq)
467 __releases(fiq->lock);
468
469 /**
470 * Clean up when fuse_iqueue is destroyed
471 */
472 void (*release)(struct fuse_iqueue *fiq);
473 };
474
475 /** /dev/fuse input queue operations */
476 extern const struct fuse_iqueue_ops fuse_dev_fiq_ops;
477
478 struct fuse_iqueue {
479 /** Connection established */
480 unsigned connected;
481
482 /** Lock protecting accesses to members of this structure */
483 spinlock_t lock;
484
485 /** Readers of the connection are waiting on this */
486 wait_queue_head_t waitq;
487
488 /** The next unique request id */
489 u64 reqctr;
490
491 /** The list of pending requests */
492 struct list_head pending;
493
494 /** Pending interrupts */
495 struct list_head interrupts;
496
497 /** Queue of pending forgets */
498 struct fuse_forget_link forget_list_head;
499 struct fuse_forget_link *forget_list_tail;
500
501 /** Batching of FORGET requests (positive indicates FORGET batch) */
502 int forget_batch;
503
504 /** O_ASYNC requests */
505 struct fasync_struct *fasync;
506
507 /** Device-specific callbacks */
508 const struct fuse_iqueue_ops *ops;
509
510 /** Device-specific state */
511 void *priv;
512 };
513
514 #define FUSE_PQ_HASH_BITS 8
515 #define FUSE_PQ_HASH_SIZE (1 << FUSE_PQ_HASH_BITS)
516
517 struct fuse_pqueue {
518 /** Connection established */
519 unsigned connected;
520
521 /** Lock protecting accessess to members of this structure */
522 spinlock_t lock;
523
524 /** Hash table of requests being processed */
525 struct list_head *processing;
526
527 /** The list of requests under I/O */
528 struct list_head io;
529 };
530
531 /**
532 * Fuse device instance
533 */
534 struct fuse_dev {
535 /** Fuse connection for this device */
536 struct fuse_conn *fc;
537
538 /** Processing queue */
539 struct fuse_pqueue pq;
540
541 /** list entry on fc->devices */
542 struct list_head entry;
543 };
544
545 enum fuse_dax_mode {
546 FUSE_DAX_INODE_DEFAULT, /* default */
547 FUSE_DAX_ALWAYS, /* "-o dax=always" */
548 FUSE_DAX_NEVER, /* "-o dax=never" */
549 FUSE_DAX_INODE_USER, /* "-o dax=inode" */
550 };
551
fuse_is_inode_dax_mode(enum fuse_dax_mode mode)552 static inline bool fuse_is_inode_dax_mode(enum fuse_dax_mode mode)
553 {
554 return mode == FUSE_DAX_INODE_DEFAULT || mode == FUSE_DAX_INODE_USER;
555 }
556
557 struct fuse_fs_context {
558 int fd;
559 struct file *file;
560 unsigned int rootmode;
561 kuid_t user_id;
562 kgid_t group_id;
563 bool is_bdev:1;
564 bool fd_present:1;
565 bool rootmode_present:1;
566 bool user_id_present:1;
567 bool group_id_present:1;
568 bool default_permissions:1;
569 bool allow_other:1;
570 bool destroy:1;
571 bool no_control:1;
572 bool no_force_umount:1;
573 bool legacy_opts_show:1;
574 enum fuse_dax_mode dax_mode;
575 unsigned int max_read;
576 unsigned int blksize;
577 const char *subtype;
578
579 /* DAX device, may be NULL */
580 struct dax_device *dax_dev;
581
582 /* fuse_dev pointer to fill in, should contain NULL on entry */
583 void **fudptr;
584 };
585
586 struct fuse_sync_bucket {
587 /* count is a possible scalability bottleneck */
588 atomic_t count;
589 wait_queue_head_t waitq;
590 struct rcu_head rcu;
591 };
592
593 /**
594 * A Fuse connection.
595 *
596 * This structure is created, when the root filesystem is mounted, and
597 * is destroyed, when the client device is closed and the last
598 * fuse_mount is destroyed.
599 */
600 struct fuse_conn {
601 /** Lock protecting accessess to members of this structure */
602 spinlock_t lock;
603
604 /** Refcount */
605 refcount_t count;
606
607 /** Number of fuse_dev's */
608 atomic_t dev_count;
609
610 struct rcu_head rcu;
611
612 /** The user id for this mount */
613 kuid_t user_id;
614
615 /** The group id for this mount */
616 kgid_t group_id;
617
618 /** The pid namespace for this mount */
619 struct pid_namespace *pid_ns;
620
621 /** The user namespace for this mount */
622 struct user_namespace *user_ns;
623
624 /** Maximum read size */
625 unsigned max_read;
626
627 /** Maximum write size */
628 unsigned max_write;
629
630 /** Maximum number of pages that can be used in a single request */
631 unsigned int max_pages;
632
633 /** Constrain ->max_pages to this value during feature negotiation */
634 unsigned int max_pages_limit;
635
636 /** Input queue */
637 struct fuse_iqueue iq;
638
639 /** The next unique kernel file handle */
640 atomic64_t khctr;
641
642 /** rbtree of fuse_files waiting for poll events indexed by ph */
643 struct rb_root polled_files;
644
645 /** Maximum number of outstanding background requests */
646 unsigned max_background;
647
648 /** Number of background requests at which congestion starts */
649 unsigned congestion_threshold;
650
651 /** Number of requests currently in the background */
652 unsigned num_background;
653
654 /** Number of background requests currently queued for userspace */
655 unsigned active_background;
656
657 /** The list of background requests set aside for later queuing */
658 struct list_head bg_queue;
659
660 /** Protects: max_background, congestion_threshold, num_background,
661 * active_background, bg_queue, blocked */
662 spinlock_t bg_lock;
663
664 /** Flag indicating that INIT reply has been received. Allocating
665 * any fuse request will be suspended until the flag is set */
666 int initialized;
667
668 /** Flag indicating if connection is blocked. This will be
669 the case before the INIT reply is received, and if there
670 are too many outstading backgrounds requests */
671 int blocked;
672
673 /** waitq for blocked connection */
674 wait_queue_head_t blocked_waitq;
675
676 /** Connection established, cleared on umount, connection
677 abort and device release */
678 unsigned connected;
679
680 /** Connection aborted via sysfs */
681 bool aborted;
682
683 /** Connection failed (version mismatch). Cannot race with
684 setting other bitfields since it is only set once in INIT
685 reply, before any other request, and never cleared */
686 unsigned conn_error:1;
687
688 /** Connection successful. Only set in INIT */
689 unsigned conn_init:1;
690
691 /** Do readahead asynchronously? Only set in INIT */
692 unsigned async_read:1;
693
694 /** Return an unique read error after abort. Only set in INIT */
695 unsigned abort_err:1;
696
697 /** Do not send separate SETATTR request before open(O_TRUNC) */
698 unsigned atomic_o_trunc:1;
699
700 /** Filesystem supports NFS exporting. Only set in INIT */
701 unsigned export_support:1;
702
703 /** write-back cache policy (default is write-through) */
704 unsigned writeback_cache:1;
705
706 /** allow parallel lookups and readdir (default is serialized) */
707 unsigned parallel_dirops:1;
708
709 /** handle fs handles killing suid/sgid/cap on write/chown/trunc */
710 unsigned handle_killpriv:1;
711
712 /** cache READLINK responses in page cache */
713 unsigned cache_symlinks:1;
714
715 /* show legacy mount options */
716 unsigned int legacy_opts_show:1;
717
718 /*
719 * fs kills suid/sgid/cap on write/chown/trunc. suid is killed on
720 * write/trunc only if caller did not have CAP_FSETID. sgid is killed
721 * on write/truncate only if caller did not have CAP_FSETID as well as
722 * file has group execute permission.
723 */
724 unsigned handle_killpriv_v2:1;
725
726 /*
727 * The following bitfields are only for optimization purposes
728 * and hence races in setting them will not cause malfunction
729 */
730
731 /** Is open/release not implemented by fs? */
732 unsigned no_open:1;
733
734 /** Is opendir/releasedir not implemented by fs? */
735 unsigned no_opendir:1;
736
737 /** Is fsync not implemented by fs? */
738 unsigned no_fsync:1;
739
740 /** Is fsyncdir not implemented by fs? */
741 unsigned no_fsyncdir:1;
742
743 /** Is flush not implemented by fs? */
744 unsigned no_flush:1;
745
746 /** Is setxattr not implemented by fs? */
747 unsigned no_setxattr:1;
748
749 /** Does file server support extended setxattr */
750 unsigned setxattr_ext:1;
751
752 /** Is getxattr not implemented by fs? */
753 unsigned no_getxattr:1;
754
755 /** Is listxattr not implemented by fs? */
756 unsigned no_listxattr:1;
757
758 /** Is removexattr not implemented by fs? */
759 unsigned no_removexattr:1;
760
761 /** Are posix file locking primitives not implemented by fs? */
762 unsigned no_lock:1;
763
764 /** Is access not implemented by fs? */
765 unsigned no_access:1;
766
767 /** Is create not implemented by fs? */
768 unsigned no_create:1;
769
770 /** Is interrupt not implemented by fs? */
771 unsigned no_interrupt:1;
772
773 /** Is bmap not implemented by fs? */
774 unsigned no_bmap:1;
775
776 /** Is poll not implemented by fs? */
777 unsigned no_poll:1;
778
779 /** Do multi-page cached writes */
780 unsigned big_writes:1;
781
782 /** Don't apply umask to creation modes */
783 unsigned dont_mask:1;
784
785 /** Are BSD file locking primitives not implemented by fs? */
786 unsigned no_flock:1;
787
788 /** Is fallocate not implemented by fs? */
789 unsigned no_fallocate:1;
790
791 /** Is rename with flags implemented by fs? */
792 unsigned no_rename2:1;
793
794 /** Use enhanced/automatic page cache invalidation. */
795 unsigned auto_inval_data:1;
796
797 /** Filesystem is fully responsible for page cache invalidation. */
798 unsigned explicit_inval_data:1;
799
800 /** Does the filesystem support readdirplus? */
801 unsigned do_readdirplus:1;
802
803 /** Does the filesystem want adaptive readdirplus? */
804 unsigned readdirplus_auto:1;
805
806 /** Does the filesystem support asynchronous direct-IO submission? */
807 unsigned async_dio:1;
808
809 /** Is lseek not implemented by fs? */
810 unsigned no_lseek:1;
811
812 /** Does the filesystem support posix acls? */
813 unsigned posix_acl:1;
814
815 /** Check permissions based on the file mode or not? */
816 unsigned default_permissions:1;
817
818 /** Allow other than the mounter user to access the filesystem ? */
819 unsigned allow_other:1;
820
821 /** Does the filesystem support copy_file_range? */
822 unsigned no_copy_file_range:1;
823
824 /* Send DESTROY request */
825 unsigned int destroy:1;
826
827 /* Delete dentries that have gone stale */
828 unsigned int delete_stale:1;
829
830 /** Do not create entry in fusectl fs */
831 unsigned int no_control:1;
832
833 /** Do not allow MNT_FORCE umount */
834 unsigned int no_force_umount:1;
835
836 /* Auto-mount submounts announced by the server */
837 unsigned int auto_submounts:1;
838
839 /* Propagate syncfs() to server */
840 unsigned int sync_fs:1;
841
842 /* Initialize security xattrs when creating a new inode */
843 unsigned int init_security:1;
844
845 /* Add supplementary group info when creating a new inode */
846 unsigned int create_supp_group:1;
847
848 /* Does the filesystem support per inode DAX? */
849 unsigned int inode_dax:1;
850
851 /* Is tmpfile not implemented by fs? */
852 unsigned int no_tmpfile:1;
853
854 /* Relax restrictions to allow shared mmap in FOPEN_DIRECT_IO mode */
855 unsigned int direct_io_allow_mmap:1;
856
857 /* Is statx not implemented by fs? */
858 unsigned int no_statx:1;
859
860 /** Passthrough support for read/write IO */
861 unsigned int passthrough:1;
862
863 /** Maximum stack depth for passthrough backing files */
864 int max_stack_depth;
865
866 /** The number of requests waiting for completion */
867 atomic_t num_waiting;
868
869 /** Negotiated minor version */
870 unsigned minor;
871
872 /** Entry on the fuse_mount_list */
873 struct list_head entry;
874
875 /** Device ID from the root super block */
876 dev_t dev;
877
878 /** Dentries in the control filesystem */
879 struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES];
880
881 /** number of dentries used in the above array */
882 int ctl_ndents;
883
884 /** Key for lock owner ID scrambling */
885 u32 scramble_key[4];
886
887 /** Version counter for attribute changes */
888 atomic64_t attr_version;
889
890 /** Called on final put */
891 void (*release)(struct fuse_conn *);
892
893 /**
894 * Read/write semaphore to hold when accessing the sb of any
895 * fuse_mount belonging to this connection
896 */
897 struct rw_semaphore killsb;
898
899 /** List of device instances belonging to this connection */
900 struct list_head devices;
901
902 #ifdef CONFIG_FUSE_DAX
903 /* Dax mode */
904 enum fuse_dax_mode dax_mode;
905
906 /* Dax specific conn data, non-NULL if DAX is enabled */
907 struct fuse_conn_dax *dax;
908 #endif
909
910 /** List of filesystems using this connection */
911 struct list_head mounts;
912
913 /* New writepages go into this bucket */
914 struct fuse_sync_bucket __rcu *curr_bucket;
915
916 #ifdef CONFIG_FUSE_PASSTHROUGH
917 /** IDR for backing files ids */
918 struct idr backing_files_map;
919 #endif
920 };
921
922 /*
923 * Represents a mounted filesystem, potentially a submount.
924 *
925 * This object allows sharing a fuse_conn between separate mounts to
926 * allow submounts with dedicated superblocks and thus separate device
927 * IDs.
928 */
929 struct fuse_mount {
930 /* Underlying (potentially shared) connection to the FUSE server */
931 struct fuse_conn *fc;
932
933 /*
934 * Super block for this connection (fc->killsb must be held when
935 * accessing this).
936 */
937 struct super_block *sb;
938
939 /* Entry on fc->mounts */
940 struct list_head fc_entry;
941 struct rcu_head rcu;
942 };
943
get_fuse_mount_super(struct super_block * sb)944 static inline struct fuse_mount *get_fuse_mount_super(struct super_block *sb)
945 {
946 return sb->s_fs_info;
947 }
948
get_fuse_conn_super(struct super_block * sb)949 static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb)
950 {
951 return get_fuse_mount_super(sb)->fc;
952 }
953
get_fuse_mount(struct inode * inode)954 static inline struct fuse_mount *get_fuse_mount(struct inode *inode)
955 {
956 return get_fuse_mount_super(inode->i_sb);
957 }
958
get_fuse_conn(struct inode * inode)959 static inline struct fuse_conn *get_fuse_conn(struct inode *inode)
960 {
961 return get_fuse_mount_super(inode->i_sb)->fc;
962 }
963
get_fuse_inode(struct inode * inode)964 static inline struct fuse_inode *get_fuse_inode(struct inode *inode)
965 {
966 return container_of(inode, struct fuse_inode, inode);
967 }
968
get_node_id(struct inode * inode)969 static inline u64 get_node_id(struct inode *inode)
970 {
971 return get_fuse_inode(inode)->nodeid;
972 }
973
invalid_nodeid(u64 nodeid)974 static inline int invalid_nodeid(u64 nodeid)
975 {
976 return !nodeid || nodeid == FUSE_ROOT_ID;
977 }
978
fuse_get_attr_version(struct fuse_conn * fc)979 static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
980 {
981 return atomic64_read(&fc->attr_version);
982 }
983
fuse_stale_inode(const struct inode * inode,int generation,struct fuse_attr * attr)984 static inline bool fuse_stale_inode(const struct inode *inode, int generation,
985 struct fuse_attr *attr)
986 {
987 return inode->i_generation != generation ||
988 inode_wrong_type(inode, attr->mode);
989 }
990
fuse_make_bad(struct inode * inode)991 static inline void fuse_make_bad(struct inode *inode)
992 {
993 set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
994 }
995
fuse_is_bad(struct inode * inode)996 static inline bool fuse_is_bad(struct inode *inode)
997 {
998 return unlikely(test_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state));
999 }
1000
fuse_pages_alloc(unsigned int npages,gfp_t flags,struct fuse_page_desc ** desc)1001 static inline struct page **fuse_pages_alloc(unsigned int npages, gfp_t flags,
1002 struct fuse_page_desc **desc)
1003 {
1004 struct page **pages;
1005
1006 pages = kzalloc(npages * (sizeof(struct page *) +
1007 sizeof(struct fuse_page_desc)), flags);
1008 *desc = (void *) (pages + npages);
1009
1010 return pages;
1011 }
1012
fuse_page_descs_length_init(struct fuse_page_desc * descs,unsigned int index,unsigned int nr_pages)1013 static inline void fuse_page_descs_length_init(struct fuse_page_desc *descs,
1014 unsigned int index,
1015 unsigned int nr_pages)
1016 {
1017 int i;
1018
1019 for (i = index; i < index + nr_pages; i++)
1020 descs[i].length = PAGE_SIZE - descs[i].offset;
1021 }
1022
fuse_sync_bucket_dec(struct fuse_sync_bucket * bucket)1023 static inline void fuse_sync_bucket_dec(struct fuse_sync_bucket *bucket)
1024 {
1025 /* Need RCU protection to prevent use after free after the decrement */
1026 rcu_read_lock();
1027 if (atomic_dec_and_test(&bucket->count))
1028 wake_up(&bucket->waitq);
1029 rcu_read_unlock();
1030 }
1031
1032 /** Device operations */
1033 extern const struct file_operations fuse_dev_operations;
1034
1035 extern const struct dentry_operations fuse_dentry_operations;
1036 extern const struct dentry_operations fuse_root_dentry_operations;
1037
1038 /**
1039 * Get a filled in inode
1040 */
1041 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
1042 int generation, struct fuse_attr *attr,
1043 u64 attr_valid, u64 attr_version);
1044
1045 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
1046 struct fuse_entry_out *outarg, struct inode **inode);
1047
1048 /**
1049 * Send FORGET command
1050 */
1051 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
1052 u64 nodeid, u64 nlookup);
1053
1054 struct fuse_forget_link *fuse_alloc_forget(void);
1055
1056 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1057 unsigned int max,
1058 unsigned int *countp);
1059
1060 /*
1061 * Initialize READ or READDIR request
1062 */
1063 struct fuse_io_args {
1064 union {
1065 struct {
1066 struct fuse_read_in in;
1067 u64 attr_ver;
1068 } read;
1069 struct {
1070 struct fuse_write_in in;
1071 struct fuse_write_out out;
1072 bool page_locked;
1073 } write;
1074 };
1075 struct fuse_args_pages ap;
1076 struct fuse_io_priv *io;
1077 struct fuse_file *ff;
1078 };
1079
1080 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
1081 size_t count, int opcode);
1082
1083
1084 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release);
1085 void fuse_file_free(struct fuse_file *ff);
1086 int fuse_finish_open(struct inode *inode, struct file *file);
1087
1088 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
1089 unsigned int flags);
1090
1091 /**
1092 * Send RELEASE or RELEASEDIR request
1093 */
1094 void fuse_release_common(struct file *file, bool isdir);
1095
1096 /**
1097 * Send FSYNC or FSYNCDIR request
1098 */
1099 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
1100 int datasync, int opcode);
1101
1102 /**
1103 * Notify poll wakeup
1104 */
1105 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
1106 struct fuse_notify_poll_wakeup_out *outarg);
1107
1108 /**
1109 * Initialize file operations on a regular file
1110 */
1111 void fuse_init_file_inode(struct inode *inode, unsigned int flags);
1112
1113 /**
1114 * Initialize inode operations on regular files and special files
1115 */
1116 void fuse_init_common(struct inode *inode);
1117
1118 /**
1119 * Initialize inode and file operations on a directory
1120 */
1121 void fuse_init_dir(struct inode *inode);
1122
1123 /**
1124 * Initialize inode operations on a symlink
1125 */
1126 void fuse_init_symlink(struct inode *inode);
1127
1128 /**
1129 * Change attributes of an inode
1130 */
1131 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
1132 struct fuse_statx *sx,
1133 u64 attr_valid, u64 attr_version);
1134
1135 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
1136 struct fuse_statx *sx,
1137 u64 attr_valid, u32 cache_mask);
1138
1139 u32 fuse_get_cache_mask(struct inode *inode);
1140
1141 /**
1142 * Initialize the client device
1143 */
1144 int fuse_dev_init(void);
1145
1146 /**
1147 * Cleanup the client device
1148 */
1149 void fuse_dev_cleanup(void);
1150
1151 int fuse_ctl_init(void);
1152 void __exit fuse_ctl_cleanup(void);
1153
1154 /**
1155 * Simple request sending that does request allocation and freeing
1156 */
1157 ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args);
1158 int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
1159 gfp_t gfp_flags);
1160
1161 /**
1162 * End a finished request
1163 */
1164 void fuse_request_end(struct fuse_req *req);
1165
1166 /* Abort all requests */
1167 void fuse_abort_conn(struct fuse_conn *fc);
1168 void fuse_wait_aborted(struct fuse_conn *fc);
1169
1170 /**
1171 * Invalidate inode attributes
1172 */
1173
1174 /* Attributes possibly changed on data modification */
1175 #define FUSE_STATX_MODIFY (STATX_MTIME | STATX_CTIME | STATX_BLOCKS)
1176
1177 /* Attributes possibly changed on data and/or size modification */
1178 #define FUSE_STATX_MODSIZE (FUSE_STATX_MODIFY | STATX_SIZE)
1179
1180 void fuse_invalidate_attr(struct inode *inode);
1181 void fuse_invalidate_attr_mask(struct inode *inode, u32 mask);
1182
1183 void fuse_invalidate_entry_cache(struct dentry *entry);
1184
1185 void fuse_invalidate_atime(struct inode *inode);
1186
1187 u64 fuse_time_to_jiffies(u64 sec, u32 nsec);
1188 #define ATTR_TIMEOUT(o) \
1189 fuse_time_to_jiffies((o)->attr_valid, (o)->attr_valid_nsec)
1190
1191 void fuse_change_entry_timeout(struct dentry *entry, struct fuse_entry_out *o);
1192
1193 /**
1194 * Acquire reference to fuse_conn
1195 */
1196 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc);
1197
1198 /**
1199 * Initialize fuse_conn
1200 */
1201 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
1202 struct user_namespace *user_ns,
1203 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv);
1204
1205 /**
1206 * Release reference to fuse_conn
1207 */
1208 void fuse_conn_put(struct fuse_conn *fc);
1209
1210 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc);
1211 struct fuse_dev *fuse_dev_alloc(void);
1212 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc);
1213 void fuse_dev_free(struct fuse_dev *fud);
1214 void fuse_send_init(struct fuse_mount *fm);
1215
1216 /**
1217 * Fill in superblock and initialize fuse connection
1218 * @sb: partially-initialized superblock to fill in
1219 * @ctx: mount context
1220 */
1221 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);
1222
1223 /*
1224 * Remove the mount from the connection
1225 *
1226 * Returns whether this was the last mount
1227 */
1228 bool fuse_mount_remove(struct fuse_mount *fm);
1229
1230 /*
1231 * Setup context ops for submounts
1232 */
1233 int fuse_init_fs_context_submount(struct fs_context *fsc);
1234
1235 /*
1236 * Shut down the connection (possibly sending DESTROY request).
1237 */
1238 void fuse_conn_destroy(struct fuse_mount *fm);
1239
1240 /* Drop the connection and free the fuse mount */
1241 void fuse_mount_destroy(struct fuse_mount *fm);
1242
1243 /**
1244 * Add connection to control filesystem
1245 */
1246 int fuse_ctl_add_conn(struct fuse_conn *fc);
1247
1248 /**
1249 * Remove connection from control filesystem
1250 */
1251 void fuse_ctl_remove_conn(struct fuse_conn *fc);
1252
1253 /**
1254 * Is file type valid?
1255 */
1256 int fuse_valid_type(int m);
1257
1258 bool fuse_invalid_attr(struct fuse_attr *attr);
1259
1260 /**
1261 * Is current process allowed to perform filesystem operation?
1262 */
1263 bool fuse_allow_current_process(struct fuse_conn *fc);
1264
1265 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id);
1266
1267 void fuse_flush_time_update(struct inode *inode);
1268 void fuse_update_ctime(struct inode *inode);
1269
1270 int fuse_update_attributes(struct inode *inode, struct file *file, u32 mask);
1271
1272 void fuse_flush_writepages(struct inode *inode);
1273
1274 void fuse_set_nowrite(struct inode *inode);
1275 void fuse_release_nowrite(struct inode *inode);
1276
1277 /**
1278 * Scan all fuse_mounts belonging to fc to find the first where
1279 * ilookup5() returns a result. Return that result and the
1280 * respective fuse_mount in *fm (unless fm is NULL).
1281 *
1282 * The caller must hold fc->killsb.
1283 */
1284 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
1285 struct fuse_mount **fm);
1286
1287 /**
1288 * File-system tells the kernel to invalidate cache for the given node id.
1289 */
1290 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
1291 loff_t offset, loff_t len);
1292
1293 /**
1294 * File-system tells the kernel to invalidate parent attributes and
1295 * the dentry matching parent/name.
1296 *
1297 * If the child_nodeid is non-zero and:
1298 * - matches the inode number for the dentry matching parent/name,
1299 * - is not a mount point
1300 * - is a file or oan empty directory
1301 * then the dentry is unhashed (d_delete()).
1302 */
1303 int fuse_reverse_inval_entry(struct fuse_conn *fc, u64 parent_nodeid,
1304 u64 child_nodeid, struct qstr *name, u32 flags);
1305
1306 int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
1307 bool isdir);
1308
1309 /**
1310 * fuse_direct_io() flags
1311 */
1312
1313 /** If set, it is WRITE; otherwise - READ */
1314 #define FUSE_DIO_WRITE (1 << 0)
1315
1316 /** CUSE pass fuse_direct_io() a file which f_mapping->host is not from FUSE */
1317 #define FUSE_DIO_CUSE (1 << 1)
1318
1319 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1320 loff_t *ppos, int flags);
1321 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1322 unsigned int flags);
1323 long fuse_ioctl_common(struct file *file, unsigned int cmd,
1324 unsigned long arg, unsigned int flags);
1325 __poll_t fuse_file_poll(struct file *file, poll_table *wait);
1326 int fuse_dev_release(struct inode *inode, struct file *file);
1327
1328 bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written);
1329
1330 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
1331 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
1332
1333 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1334 struct file *file);
1335
1336 void fuse_set_initialized(struct fuse_conn *fc);
1337
1338 void fuse_unlock_inode(struct inode *inode, bool locked);
1339 bool fuse_lock_inode(struct inode *inode);
1340
1341 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
1342 size_t size, int flags, unsigned int extra_flags);
1343 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
1344 size_t size);
1345 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size);
1346 int fuse_removexattr(struct inode *inode, const char *name);
1347 extern const struct xattr_handler * const fuse_xattr_handlers[];
1348
1349 struct posix_acl;
1350 struct posix_acl *fuse_get_inode_acl(struct inode *inode, int type, bool rcu);
1351 struct posix_acl *fuse_get_acl(struct mnt_idmap *idmap,
1352 struct dentry *dentry, int type);
1353 int fuse_set_acl(struct mnt_idmap *, struct dentry *dentry,
1354 struct posix_acl *acl, int type);
1355
1356 /* readdir.c */
1357 int fuse_readdir(struct file *file, struct dir_context *ctx);
1358
1359 /**
1360 * Return the number of bytes in an arguments list
1361 */
1362 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args);
1363
1364 /**
1365 * Get the next unique ID for a request
1366 */
1367 u64 fuse_get_unique(struct fuse_iqueue *fiq);
1368 void fuse_free_conn(struct fuse_conn *fc);
1369
1370 /* dax.c */
1371
1372 #define FUSE_IS_DAX(inode) (IS_ENABLED(CONFIG_FUSE_DAX) && IS_DAX(inode))
1373
1374 ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to);
1375 ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from);
1376 int fuse_dax_mmap(struct file *file, struct vm_area_struct *vma);
1377 int fuse_dax_break_layouts(struct inode *inode, u64 dmap_start, u64 dmap_end);
1378 int fuse_dax_conn_alloc(struct fuse_conn *fc, enum fuse_dax_mode mode,
1379 struct dax_device *dax_dev);
1380 void fuse_dax_conn_free(struct fuse_conn *fc);
1381 bool fuse_dax_inode_alloc(struct super_block *sb, struct fuse_inode *fi);
1382 void fuse_dax_inode_init(struct inode *inode, unsigned int flags);
1383 void fuse_dax_inode_cleanup(struct inode *inode);
1384 void fuse_dax_dontcache(struct inode *inode, unsigned int flags);
1385 bool fuse_dax_check_alignment(struct fuse_conn *fc, unsigned int map_alignment);
1386 void fuse_dax_cancel_work(struct fuse_conn *fc);
1387
1388 /* ioctl.c */
1389 long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
1390 long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
1391 unsigned long arg);
1392 int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa);
1393 int fuse_fileattr_set(struct mnt_idmap *idmap,
1394 struct dentry *dentry, struct fileattr *fa);
1395
1396 /* iomode.c */
1397 int fuse_file_cached_io_open(struct inode *inode, struct fuse_file *ff);
1398 int fuse_inode_uncached_io_start(struct fuse_inode *fi,
1399 struct fuse_backing *fb);
1400 void fuse_inode_uncached_io_end(struct fuse_inode *fi);
1401
1402 int fuse_file_io_open(struct file *file, struct inode *inode);
1403 void fuse_file_io_release(struct fuse_file *ff, struct inode *inode);
1404
1405 /* file.c */
1406 struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
1407 unsigned int open_flags, bool isdir);
1408 void fuse_file_release(struct inode *inode, struct fuse_file *ff,
1409 unsigned int open_flags, fl_owner_t id, bool isdir);
1410
1411 /* passthrough.c */
fuse_inode_backing(struct fuse_inode * fi)1412 static inline struct fuse_backing *fuse_inode_backing(struct fuse_inode *fi)
1413 {
1414 #ifdef CONFIG_FUSE_PASSTHROUGH
1415 return READ_ONCE(fi->fb);
1416 #else
1417 return NULL;
1418 #endif
1419 }
1420
fuse_inode_backing_set(struct fuse_inode * fi,struct fuse_backing * fb)1421 static inline struct fuse_backing *fuse_inode_backing_set(struct fuse_inode *fi,
1422 struct fuse_backing *fb)
1423 {
1424 #ifdef CONFIG_FUSE_PASSTHROUGH
1425 return xchg(&fi->fb, fb);
1426 #else
1427 return NULL;
1428 #endif
1429 }
1430
1431 #ifdef CONFIG_FUSE_PASSTHROUGH
1432 struct fuse_backing *fuse_backing_get(struct fuse_backing *fb);
1433 void fuse_backing_put(struct fuse_backing *fb);
1434 #else
1435
fuse_backing_get(struct fuse_backing * fb)1436 static inline struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
1437 {
1438 return NULL;
1439 }
1440
fuse_backing_put(struct fuse_backing * fb)1441 static inline void fuse_backing_put(struct fuse_backing *fb)
1442 {
1443 }
1444 #endif
1445
1446 void fuse_backing_files_init(struct fuse_conn *fc);
1447 void fuse_backing_files_free(struct fuse_conn *fc);
1448 int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map);
1449 int fuse_backing_close(struct fuse_conn *fc, int backing_id);
1450
1451 struct fuse_backing *fuse_passthrough_open(struct file *file,
1452 struct inode *inode,
1453 int backing_id);
1454 void fuse_passthrough_release(struct fuse_file *ff, struct fuse_backing *fb);
1455
fuse_file_passthrough(struct fuse_file * ff)1456 static inline struct file *fuse_file_passthrough(struct fuse_file *ff)
1457 {
1458 #ifdef CONFIG_FUSE_PASSTHROUGH
1459 return ff->passthrough;
1460 #else
1461 return NULL;
1462 #endif
1463 }
1464
1465 ssize_t fuse_passthrough_read_iter(struct kiocb *iocb, struct iov_iter *iter);
1466 ssize_t fuse_passthrough_write_iter(struct kiocb *iocb, struct iov_iter *iter);
1467 ssize_t fuse_passthrough_splice_read(struct file *in, loff_t *ppos,
1468 struct pipe_inode_info *pipe,
1469 size_t len, unsigned int flags);
1470 ssize_t fuse_passthrough_splice_write(struct pipe_inode_info *pipe,
1471 struct file *out, loff_t *ppos,
1472 size_t len, unsigned int flags);
1473 ssize_t fuse_passthrough_mmap(struct file *file, struct vm_area_struct *vma);
1474
1475 #endif /* _FS_FUSE_I_H */
1476