xref: /qemu/include/standard-headers/linux/fuse.h (revision f07a5674cf97b8473e5d06d7b1df9b51e97d553f)
1 /* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) */
2 /*
3     This file defines the kernel interface of FUSE
4     Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
5 
6     This program can be distributed under the terms of the GNU GPL.
7     See the file COPYING.
8 
9     This -- and only this -- header file may also be distributed under
10     the terms of the BSD Licence as follows:
11 
12     Copyright (C) 2001-2007 Miklos Szeredi. All rights reserved.
13 
14     Redistribution and use in source and binary forms, with or without
15     modification, are permitted provided that the following conditions
16     are met:
17     1. Redistributions of source code must retain the above copyright
18        notice, this list of conditions and the following disclaimer.
19     2. Redistributions in binary form must reproduce the above copyright
20        notice, this list of conditions and the following disclaimer in the
21        documentation and/or other materials provided with the distribution.
22 
23     THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26     ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
27     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31     LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33     SUCH DAMAGE.
34 */
35 
36 /*
37  * This file defines the kernel interface of FUSE
38  *
39  * Protocol changelog:
40  *
41  * 7.1:
42  *  - add the following messages:
43  *      FUSE_SETATTR, FUSE_SYMLINK, FUSE_MKNOD, FUSE_MKDIR, FUSE_UNLINK,
44  *      FUSE_RMDIR, FUSE_RENAME, FUSE_LINK, FUSE_OPEN, FUSE_READ, FUSE_WRITE,
45  *      FUSE_RELEASE, FUSE_FSYNC, FUSE_FLUSH, FUSE_SETXATTR, FUSE_GETXATTR,
46  *      FUSE_LISTXATTR, FUSE_REMOVEXATTR, FUSE_OPENDIR, FUSE_READDIR,
47  *      FUSE_RELEASEDIR
48  *  - add padding to messages to accommodate 32-bit servers on 64-bit kernels
49  *
50  * 7.2:
51  *  - add FOPEN_DIRECT_IO and FOPEN_KEEP_CACHE flags
52  *  - add FUSE_FSYNCDIR message
53  *
54  * 7.3:
55  *  - add FUSE_ACCESS message
56  *  - add FUSE_CREATE message
57  *  - add filehandle to fuse_setattr_in
58  *
59  * 7.4:
60  *  - add frsize to fuse_kstatfs
61  *  - clean up request size limit checking
62  *
63  * 7.5:
64  *  - add flags and max_write to fuse_init_out
65  *
66  * 7.6:
67  *  - add max_readahead to fuse_init_in and fuse_init_out
68  *
69  * 7.7:
70  *  - add FUSE_INTERRUPT message
71  *  - add POSIX file lock support
72  *
73  * 7.8:
74  *  - add lock_owner and flags fields to fuse_release_in
75  *  - add FUSE_BMAP message
76  *  - add FUSE_DESTROY message
77  *
78  * 7.9:
79  *  - new fuse_getattr_in input argument of GETATTR
80  *  - add lk_flags in fuse_lk_in
81  *  - add lock_owner field to fuse_setattr_in, fuse_read_in and fuse_write_in
82  *  - add blksize field to fuse_attr
83  *  - add file flags field to fuse_read_in and fuse_write_in
84  *  - Add ATIME_NOW and MTIME_NOW flags to fuse_setattr_in
85  *
86  * 7.10
87  *  - add nonseekable open flag
88  *
89  * 7.11
90  *  - add IOCTL message
91  *  - add unsolicited notification support
92  *  - add POLL message and NOTIFY_POLL notification
93  *
94  * 7.12
95  *  - add umask flag to input argument of create, mknod and mkdir
96  *  - add notification messages for invalidation of inodes and
97  *    directory entries
98  *
99  * 7.13
100  *  - make max number of background requests and congestion threshold
101  *    tunables
102  *
103  * 7.14
104  *  - add splice support to fuse device
105  *
106  * 7.15
107  *  - add store notify
108  *  - add retrieve notify
109  *
110  * 7.16
111  *  - add BATCH_FORGET request
112  *  - FUSE_IOCTL_UNRESTRICTED shall now return with array of 'struct
113  *    fuse_ioctl_iovec' instead of ambiguous 'struct iovec'
114  *  - add FUSE_IOCTL_32BIT flag
115  *
116  * 7.17
117  *  - add FUSE_FLOCK_LOCKS and FUSE_RELEASE_FLOCK_UNLOCK
118  *
119  * 7.18
120  *  - add FUSE_IOCTL_DIR flag
121  *  - add FUSE_NOTIFY_DELETE
122  *
123  * 7.19
124  *  - add FUSE_FALLOCATE
125  *
126  * 7.20
127  *  - add FUSE_AUTO_INVAL_DATA
128  *
129  * 7.21
130  *  - add FUSE_READDIRPLUS
131  *  - send the requested events in POLL request
132  *
133  * 7.22
134  *  - add FUSE_ASYNC_DIO
135  *
136  * 7.23
137  *  - add FUSE_WRITEBACK_CACHE
138  *  - add time_gran to fuse_init_out
139  *  - add reserved space to fuse_init_out
140  *  - add FATTR_CTIME
141  *  - add ctime and ctimensec to fuse_setattr_in
142  *  - add FUSE_RENAME2 request
143  *  - add FUSE_NO_OPEN_SUPPORT flag
144  *
145  *  7.24
146  *  - add FUSE_LSEEK for SEEK_HOLE and SEEK_DATA support
147  *
148  *  7.25
149  *  - add FUSE_PARALLEL_DIROPS
150  *
151  *  7.26
152  *  - add FUSE_HANDLE_KILLPRIV
153  *  - add FUSE_POSIX_ACL
154  *
155  *  7.27
156  *  - add FUSE_ABORT_ERROR
157  *
158  *  7.28
159  *  - add FUSE_COPY_FILE_RANGE
160  *  - add FOPEN_CACHE_DIR
161  *  - add FUSE_MAX_PAGES, add max_pages to init_out
162  *  - add FUSE_CACHE_SYMLINKS
163  *
164  *  7.29
165  *  - add FUSE_NO_OPENDIR_SUPPORT flag
166  *
167  *  7.30
168  *  - add FUSE_EXPLICIT_INVAL_DATA
169  *  - add FUSE_IOCTL_COMPAT_X32
170  *
171  *  7.31
172  *  - add FUSE_WRITE_KILL_PRIV flag
173  *  - add FUSE_SETUPMAPPING and FUSE_REMOVEMAPPING
174  *  - add map_alignment to fuse_init_out, add FUSE_MAP_ALIGNMENT flag
175  *
176  *  7.32
177  *  - add flags to fuse_attr, add FUSE_ATTR_SUBMOUNT, add FUSE_SUBMOUNTS
178  *
179  *  7.33
180  *  - add FUSE_HANDLE_KILLPRIV_V2, FUSE_WRITE_KILL_SUIDGID, FATTR_KILL_SUIDGID
181  *  - add FUSE_OPEN_KILL_SUIDGID
182  *  - extend fuse_setxattr_in, add FUSE_SETXATTR_EXT
183  *  - add FUSE_SETXATTR_ACL_KILL_SGID
184  *
185  *  7.34
186  *  - add FUSE_SYNCFS
187  *
188  *  7.35
189  *  - add FOPEN_NOFLUSH
190  *
191  *  7.36
192  *  - extend fuse_init_in with reserved fields, add FUSE_INIT_EXT init flag
193  *  - add flags2 to fuse_init_in and fuse_init_out
194  *  - add FUSE_SECURITY_CTX init flag
195  *  - add security context to create, mkdir, symlink, and mknod requests
196  *  - add FUSE_HAS_INODE_DAX, FUSE_ATTR_DAX
197  *
198  *  7.37
199  *  - add FUSE_TMPFILE
200  *
201  *  7.38
202  *  - add FUSE_EXPIRE_ONLY flag to fuse_notify_inval_entry
203  *  - add FOPEN_PARALLEL_DIRECT_WRITES
204  *  - add total_extlen to fuse_in_header
205  *  - add FUSE_MAX_NR_SECCTX
206  *  - add extension header
207  *  - add FUSE_EXT_GROUPS
208  *  - add FUSE_CREATE_SUPP_GROUP
209  *  - add FUSE_HAS_EXPIRE_ONLY
210  *
211  *  7.39
212  *  - add FUSE_DIRECT_IO_ALLOW_MMAP
213  *  - add FUSE_STATX and related structures
214  *
215  *  7.40
216  *  - add max_stack_depth to fuse_init_out, add FUSE_PASSTHROUGH init flag
217  *  - add backing_id to fuse_open_out, add FOPEN_PASSTHROUGH open flag
218  *  - add FUSE_NO_EXPORT_SUPPORT init flag
219  *  - add FUSE_NOTIFY_RESEND, add FUSE_HAS_RESEND init flag
220  *
221  *  7.41
222  *  - add FUSE_ALLOW_IDMAP
223  *  7.42
224  *  - Add FUSE_OVER_IO_URING and all other io-uring related flags and data
225  *    structures:
226  *    - struct fuse_uring_ent_in_out
227  *    - struct fuse_uring_req_header
228  *    - struct fuse_uring_cmd_req
229  *    - FUSE_URING_IN_OUT_HEADER_SZ
230  *    - FUSE_URING_OP_IN_OUT_SZ
231  *    - enum fuse_uring_cmd
232  */
233 
234 #ifndef _LINUX_FUSE_H
235 #define _LINUX_FUSE_H
236 
237 #include <stdint.h>
238 
239 /*
240  * Version negotiation:
241  *
242  * Both the kernel and userspace send the version they support in the
243  * INIT request and reply respectively.
244  *
245  * If the major versions match then both shall use the smallest
246  * of the two minor versions for communication.
247  *
248  * If the kernel supports a larger major version, then userspace shall
249  * reply with the major version it supports, ignore the rest of the
250  * INIT message and expect a new INIT message from the kernel with a
251  * matching major version.
252  *
253  * If the library supports a larger major version, then it shall fall
254  * back to the major protocol version sent by the kernel for
255  * communication and reply with that major version (and an arbitrary
256  * supported minor version).
257  */
258 
259 /** Version number of this interface */
260 #define FUSE_KERNEL_VERSION 7
261 
262 /** Minor version number of this interface */
263 #define FUSE_KERNEL_MINOR_VERSION 42
264 
265 /** The node ID of the root inode */
266 #define FUSE_ROOT_ID 1
267 
268 /* Make sure all structures are padded to 64bit boundary, so 32bit
269    userspace works under 64bit kernels */
270 
271 struct fuse_attr {
272 	uint64_t	ino;
273 	uint64_t	size;
274 	uint64_t	blocks;
275 	uint64_t	atime;
276 	uint64_t	mtime;
277 	uint64_t	ctime;
278 	uint32_t	atimensec;
279 	uint32_t	mtimensec;
280 	uint32_t	ctimensec;
281 	uint32_t	mode;
282 	uint32_t	nlink;
283 	uint32_t	uid;
284 	uint32_t	gid;
285 	uint32_t	rdev;
286 	uint32_t	blksize;
287 	uint32_t	flags;
288 };
289 
290 /*
291  * The following structures are bit-for-bit compatible with the statx(2) ABI in
292  * Linux.
293  */
294 struct fuse_sx_time {
295 	int64_t		tv_sec;
296 	uint32_t	tv_nsec;
297 	int32_t		__reserved;
298 };
299 
300 struct fuse_statx {
301 	uint32_t	mask;
302 	uint32_t	blksize;
303 	uint64_t	attributes;
304 	uint32_t	nlink;
305 	uint32_t	uid;
306 	uint32_t	gid;
307 	uint16_t	mode;
308 	uint16_t	__spare0[1];
309 	uint64_t	ino;
310 	uint64_t	size;
311 	uint64_t	blocks;
312 	uint64_t	attributes_mask;
313 	struct fuse_sx_time	atime;
314 	struct fuse_sx_time	btime;
315 	struct fuse_sx_time	ctime;
316 	struct fuse_sx_time	mtime;
317 	uint32_t	rdev_major;
318 	uint32_t	rdev_minor;
319 	uint32_t	dev_major;
320 	uint32_t	dev_minor;
321 	uint64_t	__spare2[14];
322 };
323 
324 struct fuse_kstatfs {
325 	uint64_t	blocks;
326 	uint64_t	bfree;
327 	uint64_t	bavail;
328 	uint64_t	files;
329 	uint64_t	ffree;
330 	uint32_t	bsize;
331 	uint32_t	namelen;
332 	uint32_t	frsize;
333 	uint32_t	padding;
334 	uint32_t	spare[6];
335 };
336 
337 struct fuse_file_lock {
338 	uint64_t	start;
339 	uint64_t	end;
340 	uint32_t	type;
341 	uint32_t	pid; /* tgid */
342 };
343 
344 /**
345  * Bitmasks for fuse_setattr_in.valid
346  */
347 #define FATTR_MODE	(1 << 0)
348 #define FATTR_UID	(1 << 1)
349 #define FATTR_GID	(1 << 2)
350 #define FATTR_SIZE	(1 << 3)
351 #define FATTR_ATIME	(1 << 4)
352 #define FATTR_MTIME	(1 << 5)
353 #define FATTR_FH	(1 << 6)
354 #define FATTR_ATIME_NOW	(1 << 7)
355 #define FATTR_MTIME_NOW	(1 << 8)
356 #define FATTR_LOCKOWNER	(1 << 9)
357 #define FATTR_CTIME	(1 << 10)
358 #define FATTR_KILL_SUIDGID	(1 << 11)
359 
360 /**
361  * Flags returned by the OPEN request
362  *
363  * FOPEN_DIRECT_IO: bypass page cache for this open file
364  * FOPEN_KEEP_CACHE: don't invalidate the data cache on open
365  * FOPEN_NONSEEKABLE: the file is not seekable
366  * FOPEN_CACHE_DIR: allow caching this directory
367  * FOPEN_STREAM: the file is stream-like (no file position at all)
368  * FOPEN_NOFLUSH: don't flush data cache on close (unless FUSE_WRITEBACK_CACHE)
369  * FOPEN_PARALLEL_DIRECT_WRITES: Allow concurrent direct writes on the same inode
370  * FOPEN_PASSTHROUGH: passthrough read/write io for this open file
371  */
372 #define FOPEN_DIRECT_IO		(1 << 0)
373 #define FOPEN_KEEP_CACHE	(1 << 1)
374 #define FOPEN_NONSEEKABLE	(1 << 2)
375 #define FOPEN_CACHE_DIR		(1 << 3)
376 #define FOPEN_STREAM		(1 << 4)
377 #define FOPEN_NOFLUSH		(1 << 5)
378 #define FOPEN_PARALLEL_DIRECT_WRITES	(1 << 6)
379 #define FOPEN_PASSTHROUGH	(1 << 7)
380 
381 /**
382  * INIT request/reply flags
383  *
384  * FUSE_ASYNC_READ: asynchronous read requests
385  * FUSE_POSIX_LOCKS: remote locking for POSIX file locks
386  * FUSE_FILE_OPS: kernel sends file handle for fstat, etc... (not yet supported)
387  * FUSE_ATOMIC_O_TRUNC: handles the O_TRUNC open flag in the filesystem
388  * FUSE_EXPORT_SUPPORT: filesystem handles lookups of "." and ".."
389  * FUSE_BIG_WRITES: filesystem can handle write size larger than 4kB
390  * FUSE_DONT_MASK: don't apply umask to file mode on create operations
391  * FUSE_SPLICE_WRITE: kernel supports splice write on the device
392  * FUSE_SPLICE_MOVE: kernel supports splice move on the device
393  * FUSE_SPLICE_READ: kernel supports splice read on the device
394  * FUSE_FLOCK_LOCKS: remote locking for BSD style file locks
395  * FUSE_HAS_IOCTL_DIR: kernel supports ioctl on directories
396  * FUSE_AUTO_INVAL_DATA: automatically invalidate cached pages
397  * FUSE_DO_READDIRPLUS: do READDIRPLUS (READDIR+LOOKUP in one)
398  * FUSE_READDIRPLUS_AUTO: adaptive readdirplus
399  * FUSE_ASYNC_DIO: asynchronous direct I/O submission
400  * FUSE_WRITEBACK_CACHE: use writeback cache for buffered writes
401  * FUSE_NO_OPEN_SUPPORT: kernel supports zero-message opens
402  * FUSE_PARALLEL_DIROPS: allow parallel lookups and readdir
403  * FUSE_HANDLE_KILLPRIV: fs handles killing suid/sgid/cap on write/chown/trunc
404  * FUSE_POSIX_ACL: filesystem supports posix acls
405  * FUSE_ABORT_ERROR: reading the device after abort returns ECONNABORTED
406  * FUSE_MAX_PAGES: init_out.max_pages contains the max number of req pages
407  * FUSE_CACHE_SYMLINKS: cache READLINK responses
408  * FUSE_NO_OPENDIR_SUPPORT: kernel supports zero-message opendir
409  * FUSE_EXPLICIT_INVAL_DATA: only invalidate cached pages on explicit request
410  * FUSE_MAP_ALIGNMENT: init_out.map_alignment contains log2(byte alignment) for
411  *		       foffset and moffset fields in struct
412  *		       fuse_setupmapping_out and fuse_removemapping_one.
413  * FUSE_SUBMOUNTS: kernel supports auto-mounting directory submounts
414  * FUSE_HANDLE_KILLPRIV_V2: fs kills suid/sgid/cap on write/chown/trunc.
415  *			Upon write/truncate suid/sgid is only killed if caller
416  *			does not have CAP_FSETID. Additionally upon
417  *			write/truncate sgid is killed only if file has group
418  *			execute permission. (Same as Linux VFS behavior).
419  * FUSE_SETXATTR_EXT:	Server supports extended struct fuse_setxattr_in
420  * FUSE_INIT_EXT: extended fuse_init_in request
421  * FUSE_INIT_RESERVED: reserved, do not use
422  * FUSE_SECURITY_CTX:	add security context to create, mkdir, symlink, and
423  *			mknod
424  * FUSE_HAS_INODE_DAX:  use per inode DAX
425  * FUSE_CREATE_SUPP_GROUP: add supplementary group info to create, mkdir,
426  *			symlink and mknod (single group that matches parent)
427  * FUSE_HAS_EXPIRE_ONLY: kernel supports expiry-only entry invalidation
428  * FUSE_DIRECT_IO_ALLOW_MMAP: allow shared mmap in FOPEN_DIRECT_IO mode.
429  * FUSE_NO_EXPORT_SUPPORT: explicitly disable export support
430  * FUSE_HAS_RESEND: kernel supports resending pending requests, and the high bit
431  *		    of the request ID indicates resend requests
432  * FUSE_ALLOW_IDMAP: allow creation of idmapped mounts
433  * FUSE_OVER_IO_URING: Indicate that client supports io-uring
434  */
435 #define FUSE_ASYNC_READ		(1 << 0)
436 #define FUSE_POSIX_LOCKS	(1 << 1)
437 #define FUSE_FILE_OPS		(1 << 2)
438 #define FUSE_ATOMIC_O_TRUNC	(1 << 3)
439 #define FUSE_EXPORT_SUPPORT	(1 << 4)
440 #define FUSE_BIG_WRITES		(1 << 5)
441 #define FUSE_DONT_MASK		(1 << 6)
442 #define FUSE_SPLICE_WRITE	(1 << 7)
443 #define FUSE_SPLICE_MOVE	(1 << 8)
444 #define FUSE_SPLICE_READ	(1 << 9)
445 #define FUSE_FLOCK_LOCKS	(1 << 10)
446 #define FUSE_HAS_IOCTL_DIR	(1 << 11)
447 #define FUSE_AUTO_INVAL_DATA	(1 << 12)
448 #define FUSE_DO_READDIRPLUS	(1 << 13)
449 #define FUSE_READDIRPLUS_AUTO	(1 << 14)
450 #define FUSE_ASYNC_DIO		(1 << 15)
451 #define FUSE_WRITEBACK_CACHE	(1 << 16)
452 #define FUSE_NO_OPEN_SUPPORT	(1 << 17)
453 #define FUSE_PARALLEL_DIROPS    (1 << 18)
454 #define FUSE_HANDLE_KILLPRIV	(1 << 19)
455 #define FUSE_POSIX_ACL		(1 << 20)
456 #define FUSE_ABORT_ERROR	(1 << 21)
457 #define FUSE_MAX_PAGES		(1 << 22)
458 #define FUSE_CACHE_SYMLINKS	(1 << 23)
459 #define FUSE_NO_OPENDIR_SUPPORT (1 << 24)
460 #define FUSE_EXPLICIT_INVAL_DATA (1 << 25)
461 #define FUSE_MAP_ALIGNMENT	(1 << 26)
462 #define FUSE_SUBMOUNTS		(1 << 27)
463 #define FUSE_HANDLE_KILLPRIV_V2	(1 << 28)
464 #define FUSE_SETXATTR_EXT	(1 << 29)
465 #define FUSE_INIT_EXT		(1 << 30)
466 #define FUSE_INIT_RESERVED	(1 << 31)
467 /* bits 32..63 get shifted down 32 bits into the flags2 field */
468 #define FUSE_SECURITY_CTX	(1ULL << 32)
469 #define FUSE_HAS_INODE_DAX	(1ULL << 33)
470 #define FUSE_CREATE_SUPP_GROUP	(1ULL << 34)
471 #define FUSE_HAS_EXPIRE_ONLY	(1ULL << 35)
472 #define FUSE_DIRECT_IO_ALLOW_MMAP (1ULL << 36)
473 #define FUSE_PASSTHROUGH	(1ULL << 37)
474 #define FUSE_NO_EXPORT_SUPPORT	(1ULL << 38)
475 #define FUSE_HAS_RESEND		(1ULL << 39)
476 
477 /* Obsolete alias for FUSE_DIRECT_IO_ALLOW_MMAP */
478 #define FUSE_DIRECT_IO_RELAX	FUSE_DIRECT_IO_ALLOW_MMAP
479 #define FUSE_ALLOW_IDMAP	(1ULL << 40)
480 #define FUSE_OVER_IO_URING	(1ULL << 41)
481 
482 /**
483  * CUSE INIT request/reply flags
484  *
485  * CUSE_UNRESTRICTED_IOCTL:  use unrestricted ioctl
486  */
487 #define CUSE_UNRESTRICTED_IOCTL	(1 << 0)
488 
489 /**
490  * Release flags
491  */
492 #define FUSE_RELEASE_FLUSH	(1 << 0)
493 #define FUSE_RELEASE_FLOCK_UNLOCK	(1 << 1)
494 
495 /**
496  * Getattr flags
497  */
498 #define FUSE_GETATTR_FH		(1 << 0)
499 
500 /**
501  * Lock flags
502  */
503 #define FUSE_LK_FLOCK		(1 << 0)
504 
505 /**
506  * WRITE flags
507  *
508  * FUSE_WRITE_CACHE: delayed write from page cache, file handle is guessed
509  * FUSE_WRITE_LOCKOWNER: lock_owner field is valid
510  * FUSE_WRITE_KILL_SUIDGID: kill suid and sgid bits
511  */
512 #define FUSE_WRITE_CACHE	(1 << 0)
513 #define FUSE_WRITE_LOCKOWNER	(1 << 1)
514 #define FUSE_WRITE_KILL_SUIDGID (1 << 2)
515 
516 /* Obsolete alias; this flag implies killing suid/sgid only. */
517 #define FUSE_WRITE_KILL_PRIV	FUSE_WRITE_KILL_SUIDGID
518 
519 /**
520  * Read flags
521  */
522 #define FUSE_READ_LOCKOWNER	(1 << 1)
523 
524 /**
525  * Ioctl flags
526  *
527  * FUSE_IOCTL_COMPAT: 32bit compat ioctl on 64bit machine
528  * FUSE_IOCTL_UNRESTRICTED: not restricted to well-formed ioctls, retry allowed
529  * FUSE_IOCTL_RETRY: retry with new iovecs
530  * FUSE_IOCTL_32BIT: 32bit ioctl
531  * FUSE_IOCTL_DIR: is a directory
532  * FUSE_IOCTL_COMPAT_X32: x32 compat ioctl on 64bit machine (64bit time_t)
533  *
534  * FUSE_IOCTL_MAX_IOV: maximum of in_iovecs + out_iovecs
535  */
536 #define FUSE_IOCTL_COMPAT	(1 << 0)
537 #define FUSE_IOCTL_UNRESTRICTED	(1 << 1)
538 #define FUSE_IOCTL_RETRY	(1 << 2)
539 #define FUSE_IOCTL_32BIT	(1 << 3)
540 #define FUSE_IOCTL_DIR		(1 << 4)
541 #define FUSE_IOCTL_COMPAT_X32	(1 << 5)
542 
543 #define FUSE_IOCTL_MAX_IOV	256
544 
545 /**
546  * Poll flags
547  *
548  * FUSE_POLL_SCHEDULE_NOTIFY: request poll notify
549  */
550 #define FUSE_POLL_SCHEDULE_NOTIFY (1 << 0)
551 
552 /**
553  * Fsync flags
554  *
555  * FUSE_FSYNC_FDATASYNC: Sync data only, not metadata
556  */
557 #define FUSE_FSYNC_FDATASYNC	(1 << 0)
558 
559 /**
560  * fuse_attr flags
561  *
562  * FUSE_ATTR_SUBMOUNT: Object is a submount root
563  * FUSE_ATTR_DAX: Enable DAX for this file in per inode DAX mode
564  */
565 #define FUSE_ATTR_SUBMOUNT      (1 << 0)
566 #define FUSE_ATTR_DAX		(1 << 1)
567 
568 /**
569  * Open flags
570  * FUSE_OPEN_KILL_SUIDGID: Kill suid and sgid if executable
571  */
572 #define FUSE_OPEN_KILL_SUIDGID	(1 << 0)
573 
574 /**
575  * setxattr flags
576  * FUSE_SETXATTR_ACL_KILL_SGID: Clear SGID when system.posix_acl_access is set
577  */
578 #define FUSE_SETXATTR_ACL_KILL_SGID	(1 << 0)
579 
580 /**
581  * notify_inval_entry flags
582  * FUSE_EXPIRE_ONLY
583  */
584 #define FUSE_EXPIRE_ONLY		(1 << 0)
585 
586 /**
587  * extension type
588  * FUSE_MAX_NR_SECCTX: maximum value of &fuse_secctx_header.nr_secctx
589  * FUSE_EXT_GROUPS: &fuse_supp_groups extension
590  */
591 enum fuse_ext_type {
592 	/* Types 0..31 are reserved for fuse_secctx_header */
593 	FUSE_MAX_NR_SECCTX	= 31,
594 	FUSE_EXT_GROUPS		= 32,
595 };
596 
597 enum fuse_opcode {
598 	FUSE_LOOKUP		= 1,
599 	FUSE_FORGET		= 2,  /* no reply */
600 	FUSE_GETATTR		= 3,
601 	FUSE_SETATTR		= 4,
602 	FUSE_READLINK		= 5,
603 	FUSE_SYMLINK		= 6,
604 	FUSE_MKNOD		= 8,
605 	FUSE_MKDIR		= 9,
606 	FUSE_UNLINK		= 10,
607 	FUSE_RMDIR		= 11,
608 	FUSE_RENAME		= 12,
609 	FUSE_LINK		= 13,
610 	FUSE_OPEN		= 14,
611 	FUSE_READ		= 15,
612 	FUSE_WRITE		= 16,
613 	FUSE_STATFS		= 17,
614 	FUSE_RELEASE		= 18,
615 	FUSE_FSYNC		= 20,
616 	FUSE_SETXATTR		= 21,
617 	FUSE_GETXATTR		= 22,
618 	FUSE_LISTXATTR		= 23,
619 	FUSE_REMOVEXATTR	= 24,
620 	FUSE_FLUSH		= 25,
621 	FUSE_INIT		= 26,
622 	FUSE_OPENDIR		= 27,
623 	FUSE_READDIR		= 28,
624 	FUSE_RELEASEDIR		= 29,
625 	FUSE_FSYNCDIR		= 30,
626 	FUSE_GETLK		= 31,
627 	FUSE_SETLK		= 32,
628 	FUSE_SETLKW		= 33,
629 	FUSE_ACCESS		= 34,
630 	FUSE_CREATE		= 35,
631 	FUSE_INTERRUPT		= 36,
632 	FUSE_BMAP		= 37,
633 	FUSE_DESTROY		= 38,
634 	FUSE_IOCTL		= 39,
635 	FUSE_POLL		= 40,
636 	FUSE_NOTIFY_REPLY	= 41,
637 	FUSE_BATCH_FORGET	= 42,
638 	FUSE_FALLOCATE		= 43,
639 	FUSE_READDIRPLUS	= 44,
640 	FUSE_RENAME2		= 45,
641 	FUSE_LSEEK		= 46,
642 	FUSE_COPY_FILE_RANGE	= 47,
643 	FUSE_SETUPMAPPING	= 48,
644 	FUSE_REMOVEMAPPING	= 49,
645 	FUSE_SYNCFS		= 50,
646 	FUSE_TMPFILE		= 51,
647 	FUSE_STATX		= 52,
648 
649 	/* CUSE specific operations */
650 	CUSE_INIT		= 4096,
651 
652 	/* Reserved opcodes: helpful to detect structure endian-ness */
653 	CUSE_INIT_BSWAP_RESERVED	= 1048576,	/* CUSE_INIT << 8 */
654 	FUSE_INIT_BSWAP_RESERVED	= 436207616,	/* FUSE_INIT << 24 */
655 };
656 
657 enum fuse_notify_code {
658 	FUSE_NOTIFY_POLL   = 1,
659 	FUSE_NOTIFY_INVAL_INODE = 2,
660 	FUSE_NOTIFY_INVAL_ENTRY = 3,
661 	FUSE_NOTIFY_STORE = 4,
662 	FUSE_NOTIFY_RETRIEVE = 5,
663 	FUSE_NOTIFY_DELETE = 6,
664 	FUSE_NOTIFY_RESEND = 7,
665 	FUSE_NOTIFY_CODE_MAX,
666 };
667 
668 /* The read buffer is required to be at least 8k, but may be much larger */
669 #define FUSE_MIN_READ_BUFFER 8192
670 
671 #define FUSE_COMPAT_ENTRY_OUT_SIZE 120
672 
673 struct fuse_entry_out {
674 	uint64_t	nodeid;		/* Inode ID */
675 	uint64_t	generation;	/* Inode generation: nodeid:gen must
676 					   be unique for the fs's lifetime */
677 	uint64_t	entry_valid;	/* Cache timeout for the name */
678 	uint64_t	attr_valid;	/* Cache timeout for the attributes */
679 	uint32_t	entry_valid_nsec;
680 	uint32_t	attr_valid_nsec;
681 	struct fuse_attr attr;
682 };
683 
684 struct fuse_forget_in {
685 	uint64_t	nlookup;
686 };
687 
688 struct fuse_forget_one {
689 	uint64_t	nodeid;
690 	uint64_t	nlookup;
691 };
692 
693 struct fuse_batch_forget_in {
694 	uint32_t	count;
695 	uint32_t	dummy;
696 };
697 
698 struct fuse_getattr_in {
699 	uint32_t	getattr_flags;
700 	uint32_t	dummy;
701 	uint64_t	fh;
702 };
703 
704 #define FUSE_COMPAT_ATTR_OUT_SIZE 96
705 
706 struct fuse_attr_out {
707 	uint64_t	attr_valid;	/* Cache timeout for the attributes */
708 	uint32_t	attr_valid_nsec;
709 	uint32_t	dummy;
710 	struct fuse_attr attr;
711 };
712 
713 struct fuse_statx_in {
714 	uint32_t	getattr_flags;
715 	uint32_t	reserved;
716 	uint64_t	fh;
717 	uint32_t	sx_flags;
718 	uint32_t	sx_mask;
719 };
720 
721 struct fuse_statx_out {
722 	uint64_t	attr_valid;	/* Cache timeout for the attributes */
723 	uint32_t	attr_valid_nsec;
724 	uint32_t	flags;
725 	uint64_t	spare[2];
726 	struct fuse_statx stat;
727 };
728 
729 #define FUSE_COMPAT_MKNOD_IN_SIZE 8
730 
731 struct fuse_mknod_in {
732 	uint32_t	mode;
733 	uint32_t	rdev;
734 	uint32_t	umask;
735 	uint32_t	padding;
736 };
737 
738 struct fuse_mkdir_in {
739 	uint32_t	mode;
740 	uint32_t	umask;
741 };
742 
743 struct fuse_rename_in {
744 	uint64_t	newdir;
745 };
746 
747 struct fuse_rename2_in {
748 	uint64_t	newdir;
749 	uint32_t	flags;
750 	uint32_t	padding;
751 };
752 
753 struct fuse_link_in {
754 	uint64_t	oldnodeid;
755 };
756 
757 struct fuse_setattr_in {
758 	uint32_t	valid;
759 	uint32_t	padding;
760 	uint64_t	fh;
761 	uint64_t	size;
762 	uint64_t	lock_owner;
763 	uint64_t	atime;
764 	uint64_t	mtime;
765 	uint64_t	ctime;
766 	uint32_t	atimensec;
767 	uint32_t	mtimensec;
768 	uint32_t	ctimensec;
769 	uint32_t	mode;
770 	uint32_t	unused4;
771 	uint32_t	uid;
772 	uint32_t	gid;
773 	uint32_t	unused5;
774 };
775 
776 struct fuse_open_in {
777 	uint32_t	flags;
778 	uint32_t	open_flags;	/* FUSE_OPEN_... */
779 };
780 
781 struct fuse_create_in {
782 	uint32_t	flags;
783 	uint32_t	mode;
784 	uint32_t	umask;
785 	uint32_t	open_flags;	/* FUSE_OPEN_... */
786 };
787 
788 struct fuse_open_out {
789 	uint64_t	fh;
790 	uint32_t	open_flags;
791 	int32_t		backing_id;
792 };
793 
794 struct fuse_release_in {
795 	uint64_t	fh;
796 	uint32_t	flags;
797 	uint32_t	release_flags;
798 	uint64_t	lock_owner;
799 };
800 
801 struct fuse_flush_in {
802 	uint64_t	fh;
803 	uint32_t	unused;
804 	uint32_t	padding;
805 	uint64_t	lock_owner;
806 };
807 
808 struct fuse_read_in {
809 	uint64_t	fh;
810 	uint64_t	offset;
811 	uint32_t	size;
812 	uint32_t	read_flags;
813 	uint64_t	lock_owner;
814 	uint32_t	flags;
815 	uint32_t	padding;
816 };
817 
818 #define FUSE_COMPAT_WRITE_IN_SIZE 24
819 
820 struct fuse_write_in {
821 	uint64_t	fh;
822 	uint64_t	offset;
823 	uint32_t	size;
824 	uint32_t	write_flags;
825 	uint64_t	lock_owner;
826 	uint32_t	flags;
827 	uint32_t	padding;
828 };
829 
830 struct fuse_write_out {
831 	uint32_t	size;
832 	uint32_t	padding;
833 };
834 
835 #define FUSE_COMPAT_STATFS_SIZE 48
836 
837 struct fuse_statfs_out {
838 	struct fuse_kstatfs st;
839 };
840 
841 struct fuse_fsync_in {
842 	uint64_t	fh;
843 	uint32_t	fsync_flags;
844 	uint32_t	padding;
845 };
846 
847 #define FUSE_COMPAT_SETXATTR_IN_SIZE 8
848 
849 struct fuse_setxattr_in {
850 	uint32_t	size;
851 	uint32_t	flags;
852 	uint32_t	setxattr_flags;
853 	uint32_t	padding;
854 };
855 
856 struct fuse_getxattr_in {
857 	uint32_t	size;
858 	uint32_t	padding;
859 };
860 
861 struct fuse_getxattr_out {
862 	uint32_t	size;
863 	uint32_t	padding;
864 };
865 
866 struct fuse_lk_in {
867 	uint64_t	fh;
868 	uint64_t	owner;
869 	struct fuse_file_lock lk;
870 	uint32_t	lk_flags;
871 	uint32_t	padding;
872 };
873 
874 struct fuse_lk_out {
875 	struct fuse_file_lock lk;
876 };
877 
878 struct fuse_access_in {
879 	uint32_t	mask;
880 	uint32_t	padding;
881 };
882 
883 struct fuse_init_in {
884 	uint32_t	major;
885 	uint32_t	minor;
886 	uint32_t	max_readahead;
887 	uint32_t	flags;
888 	uint32_t	flags2;
889 	uint32_t	unused[11];
890 };
891 
892 #define FUSE_COMPAT_INIT_OUT_SIZE 8
893 #define FUSE_COMPAT_22_INIT_OUT_SIZE 24
894 
895 struct fuse_init_out {
896 	uint32_t	major;
897 	uint32_t	minor;
898 	uint32_t	max_readahead;
899 	uint32_t	flags;
900 	uint16_t	max_background;
901 	uint16_t	congestion_threshold;
902 	uint32_t	max_write;
903 	uint32_t	time_gran;
904 	uint16_t	max_pages;
905 	uint16_t	map_alignment;
906 	uint32_t	flags2;
907 	uint32_t	max_stack_depth;
908 	uint32_t	unused[6];
909 };
910 
911 #define CUSE_INIT_INFO_MAX 4096
912 
913 struct cuse_init_in {
914 	uint32_t	major;
915 	uint32_t	minor;
916 	uint32_t	unused;
917 	uint32_t	flags;
918 };
919 
920 struct cuse_init_out {
921 	uint32_t	major;
922 	uint32_t	minor;
923 	uint32_t	unused;
924 	uint32_t	flags;
925 	uint32_t	max_read;
926 	uint32_t	max_write;
927 	uint32_t	dev_major;		/* chardev major */
928 	uint32_t	dev_minor;		/* chardev minor */
929 	uint32_t	spare[10];
930 };
931 
932 struct fuse_interrupt_in {
933 	uint64_t	unique;
934 };
935 
936 struct fuse_bmap_in {
937 	uint64_t	block;
938 	uint32_t	blocksize;
939 	uint32_t	padding;
940 };
941 
942 struct fuse_bmap_out {
943 	uint64_t	block;
944 };
945 
946 struct fuse_ioctl_in {
947 	uint64_t	fh;
948 	uint32_t	flags;
949 	uint32_t	cmd;
950 	uint64_t	arg;
951 	uint32_t	in_size;
952 	uint32_t	out_size;
953 };
954 
955 struct fuse_ioctl_iovec {
956 	uint64_t	base;
957 	uint64_t	len;
958 };
959 
960 struct fuse_ioctl_out {
961 	int32_t		result;
962 	uint32_t	flags;
963 	uint32_t	in_iovs;
964 	uint32_t	out_iovs;
965 };
966 
967 struct fuse_poll_in {
968 	uint64_t	fh;
969 	uint64_t	kh;
970 	uint32_t	flags;
971 	uint32_t	events;
972 };
973 
974 struct fuse_poll_out {
975 	uint32_t	revents;
976 	uint32_t	padding;
977 };
978 
979 struct fuse_notify_poll_wakeup_out {
980 	uint64_t	kh;
981 };
982 
983 struct fuse_fallocate_in {
984 	uint64_t	fh;
985 	uint64_t	offset;
986 	uint64_t	length;
987 	uint32_t	mode;
988 	uint32_t	padding;
989 };
990 
991 /**
992  * FUSE request unique ID flag
993  *
994  * Indicates whether this is a resend request. The receiver should handle this
995  * request accordingly.
996  */
997 #define FUSE_UNIQUE_RESEND (1ULL << 63)
998 
999 /**
1000  * This value will be set by the kernel to
1001  * (struct fuse_in_header).{uid,gid} fields in
1002  * case when:
1003  * - fuse daemon enabled FUSE_ALLOW_IDMAP
1004  * - idmapping information is not available and uid/gid
1005  *   can not be mapped in accordance with an idmapping.
1006  *
1007  * Note: an idmapping information always available
1008  * for inode creation operations like:
1009  * FUSE_MKNOD, FUSE_SYMLINK, FUSE_MKDIR, FUSE_TMPFILE,
1010  * FUSE_CREATE and FUSE_RENAME2 (with RENAME_WHITEOUT).
1011  */
1012 #define FUSE_INVALID_UIDGID ((uint32_t)(-1))
1013 
1014 struct fuse_in_header {
1015 	uint32_t	len;
1016 	uint32_t	opcode;
1017 	uint64_t	unique;
1018 	uint64_t	nodeid;
1019 	uint32_t	uid;
1020 	uint32_t	gid;
1021 	uint32_t	pid;
1022 	uint16_t	total_extlen; /* length of extensions in 8byte units */
1023 	uint16_t	padding;
1024 };
1025 
1026 struct fuse_out_header {
1027 	uint32_t	len;
1028 	int32_t		error;
1029 	uint64_t	unique;
1030 };
1031 
1032 struct fuse_dirent {
1033 	uint64_t	ino;
1034 	uint64_t	off;
1035 	uint32_t	namelen;
1036 	uint32_t	type;
1037 	char name[];
1038 };
1039 
1040 /* Align variable length records to 64bit boundary */
1041 #define FUSE_REC_ALIGN(x) \
1042 	(((x) + sizeof(uint64_t) - 1) & ~(sizeof(uint64_t) - 1))
1043 
1044 #define FUSE_NAME_OFFSET offsetof(struct fuse_dirent, name)
1045 #define FUSE_DIRENT_ALIGN(x) FUSE_REC_ALIGN(x)
1046 #define FUSE_DIRENT_SIZE(d) \
1047 	FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)
1048 
1049 struct fuse_direntplus {
1050 	struct fuse_entry_out entry_out;
1051 	struct fuse_dirent dirent;
1052 };
1053 
1054 #define FUSE_NAME_OFFSET_DIRENTPLUS \
1055 	offsetof(struct fuse_direntplus, dirent.name)
1056 #define FUSE_DIRENTPLUS_SIZE(d) \
1057 	FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET_DIRENTPLUS + (d)->dirent.namelen)
1058 
1059 struct fuse_notify_inval_inode_out {
1060 	uint64_t	ino;
1061 	int64_t		off;
1062 	int64_t		len;
1063 };
1064 
1065 struct fuse_notify_inval_entry_out {
1066 	uint64_t	parent;
1067 	uint32_t	namelen;
1068 	uint32_t	flags;
1069 };
1070 
1071 struct fuse_notify_delete_out {
1072 	uint64_t	parent;
1073 	uint64_t	child;
1074 	uint32_t	namelen;
1075 	uint32_t	padding;
1076 };
1077 
1078 struct fuse_notify_store_out {
1079 	uint64_t	nodeid;
1080 	uint64_t	offset;
1081 	uint32_t	size;
1082 	uint32_t	padding;
1083 };
1084 
1085 struct fuse_notify_retrieve_out {
1086 	uint64_t	notify_unique;
1087 	uint64_t	nodeid;
1088 	uint64_t	offset;
1089 	uint32_t	size;
1090 	uint32_t	padding;
1091 };
1092 
1093 /* Matches the size of fuse_write_in */
1094 struct fuse_notify_retrieve_in {
1095 	uint64_t	dummy1;
1096 	uint64_t	offset;
1097 	uint32_t	size;
1098 	uint32_t	dummy2;
1099 	uint64_t	dummy3;
1100 	uint64_t	dummy4;
1101 };
1102 
1103 struct fuse_backing_map {
1104 	int32_t		fd;
1105 	uint32_t	flags;
1106 	uint64_t	padding;
1107 };
1108 
1109 /* Device ioctls: */
1110 #define FUSE_DEV_IOC_MAGIC		229
1111 #define FUSE_DEV_IOC_CLONE		_IOR(FUSE_DEV_IOC_MAGIC, 0, uint32_t)
1112 #define FUSE_DEV_IOC_BACKING_OPEN	_IOW(FUSE_DEV_IOC_MAGIC, 1, \
1113 					     struct fuse_backing_map)
1114 #define FUSE_DEV_IOC_BACKING_CLOSE	_IOW(FUSE_DEV_IOC_MAGIC, 2, uint32_t)
1115 
1116 struct fuse_lseek_in {
1117 	uint64_t	fh;
1118 	uint64_t	offset;
1119 	uint32_t	whence;
1120 	uint32_t	padding;
1121 };
1122 
1123 struct fuse_lseek_out {
1124 	uint64_t	offset;
1125 };
1126 
1127 struct fuse_copy_file_range_in {
1128 	uint64_t	fh_in;
1129 	uint64_t	off_in;
1130 	uint64_t	nodeid_out;
1131 	uint64_t	fh_out;
1132 	uint64_t	off_out;
1133 	uint64_t	len;
1134 	uint64_t	flags;
1135 };
1136 
1137 #define FUSE_SETUPMAPPING_FLAG_WRITE (1ull << 0)
1138 #define FUSE_SETUPMAPPING_FLAG_READ (1ull << 1)
1139 struct fuse_setupmapping_in {
1140 	/* An already open handle */
1141 	uint64_t	fh;
1142 	/* Offset into the file to start the mapping */
1143 	uint64_t	foffset;
1144 	/* Length of mapping required */
1145 	uint64_t	len;
1146 	/* Flags, FUSE_SETUPMAPPING_FLAG_* */
1147 	uint64_t	flags;
1148 	/* Offset in Memory Window */
1149 	uint64_t	moffset;
1150 };
1151 
1152 struct fuse_removemapping_in {
1153 	/* number of fuse_removemapping_one follows */
1154 	uint32_t        count;
1155 };
1156 
1157 struct fuse_removemapping_one {
1158 	/* Offset into the dax window start the unmapping */
1159 	uint64_t        moffset;
1160 	/* Length of mapping required */
1161 	uint64_t	len;
1162 };
1163 
1164 #define FUSE_REMOVEMAPPING_MAX_ENTRY   \
1165 		(PAGE_SIZE / sizeof(struct fuse_removemapping_one))
1166 
1167 struct fuse_syncfs_in {
1168 	uint64_t	padding;
1169 };
1170 
1171 /*
1172  * For each security context, send fuse_secctx with size of security context
1173  * fuse_secctx will be followed by security context name and this in turn
1174  * will be followed by actual context label.
1175  * fuse_secctx, name, context
1176  */
1177 struct fuse_secctx {
1178 	uint32_t	size;
1179 	uint32_t	padding;
1180 };
1181 
1182 /*
1183  * Contains the information about how many fuse_secctx structures are being
1184  * sent and what's the total size of all security contexts (including
1185  * size of fuse_secctx_header).
1186  *
1187  */
1188 struct fuse_secctx_header {
1189 	uint32_t	size;
1190 	uint32_t	nr_secctx;
1191 };
1192 
1193 /**
1194  * struct fuse_ext_header - extension header
1195  * @size: total size of this extension including this header
1196  * @type: type of extension
1197  *
1198  * This is made compatible with fuse_secctx_header by using type values >
1199  * FUSE_MAX_NR_SECCTX
1200  */
1201 struct fuse_ext_header {
1202 	uint32_t	size;
1203 	uint32_t	type;
1204 };
1205 
1206 /**
1207  * struct fuse_supp_groups - Supplementary group extension
1208  * @nr_groups: number of supplementary groups
1209  * @groups: flexible array of group IDs
1210  */
1211 struct fuse_supp_groups {
1212 	uint32_t	nr_groups;
1213 	uint32_t	groups[];
1214 };
1215 
1216 /**
1217  * Size of the ring buffer header
1218  */
1219 #define FUSE_URING_IN_OUT_HEADER_SZ 128
1220 #define FUSE_URING_OP_IN_OUT_SZ 128
1221 
1222 /* Used as part of the fuse_uring_req_header */
1223 struct fuse_uring_ent_in_out {
1224 	uint64_t flags;
1225 
1226 	/*
1227 	 * commit ID to be used in a reply to a ring request (see also
1228 	 * struct fuse_uring_cmd_req)
1229 	 */
1230 	uint64_t commit_id;
1231 
1232 	/* size of user payload buffer */
1233 	uint32_t payload_sz;
1234 	uint32_t padding;
1235 
1236 	uint64_t reserved;
1237 };
1238 
1239 /**
1240  * Header for all fuse-io-uring requests
1241  */
1242 struct fuse_uring_req_header {
1243 	/* struct fuse_in_header / struct fuse_out_header */
1244 	char in_out[FUSE_URING_IN_OUT_HEADER_SZ];
1245 
1246 	/* per op code header */
1247 	char op_in[FUSE_URING_OP_IN_OUT_SZ];
1248 
1249 	struct fuse_uring_ent_in_out ring_ent_in_out;
1250 };
1251 
1252 /**
1253  * sqe commands to the kernel
1254  */
1255 enum fuse_uring_cmd {
1256 	FUSE_IO_URING_CMD_INVALID = 0,
1257 
1258 	/* register the request buffer and fetch a fuse request */
1259 	FUSE_IO_URING_CMD_REGISTER = 1,
1260 
1261 	/* commit fuse request result and fetch next request */
1262 	FUSE_IO_URING_CMD_COMMIT_AND_FETCH = 2,
1263 };
1264 
1265 /**
1266  * In the 80B command area of the SQE.
1267  */
1268 struct fuse_uring_cmd_req {
1269 	uint64_t flags;
1270 
1271 	/* entry identifier for commits */
1272 	uint64_t commit_id;
1273 
1274 	/* queue the command is for (queue index) */
1275 	uint16_t qid;
1276 	uint8_t padding[6];
1277 };
1278 
1279 #endif /* _LINUX_FUSE_H */
1280