4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5 * http://www.samsung.com/
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/f2fs_fs.h>
18 static unsigned long dir_blocks(struct inode
*inode
)
20 return ((unsigned long long) (i_size_read(inode
) + PAGE_CACHE_SIZE
- 1))
24 static unsigned int dir_buckets(unsigned int level
, int dir_level
)
26 if (level
+ dir_level
< MAX_DIR_HASH_DEPTH
/ 2)
27 return 1 << (level
+ dir_level
);
29 return MAX_DIR_BUCKETS
;
32 static unsigned int bucket_blocks(unsigned int level
)
34 if (level
< MAX_DIR_HASH_DEPTH
/ 2)
40 unsigned char f2fs_filetype_table
[F2FS_FT_MAX
] = {
41 [F2FS_FT_UNKNOWN
] = DT_UNKNOWN
,
42 [F2FS_FT_REG_FILE
] = DT_REG
,
43 [F2FS_FT_DIR
] = DT_DIR
,
44 [F2FS_FT_CHRDEV
] = DT_CHR
,
45 [F2FS_FT_BLKDEV
] = DT_BLK
,
46 [F2FS_FT_FIFO
] = DT_FIFO
,
47 [F2FS_FT_SOCK
] = DT_SOCK
,
48 [F2FS_FT_SYMLINK
] = DT_LNK
,
52 static unsigned char f2fs_type_by_mode
[S_IFMT
>> S_SHIFT
] = {
53 [S_IFREG
>> S_SHIFT
] = F2FS_FT_REG_FILE
,
54 [S_IFDIR
>> S_SHIFT
] = F2FS_FT_DIR
,
55 [S_IFCHR
>> S_SHIFT
] = F2FS_FT_CHRDEV
,
56 [S_IFBLK
>> S_SHIFT
] = F2FS_FT_BLKDEV
,
57 [S_IFIFO
>> S_SHIFT
] = F2FS_FT_FIFO
,
58 [S_IFSOCK
>> S_SHIFT
] = F2FS_FT_SOCK
,
59 [S_IFLNK
>> S_SHIFT
] = F2FS_FT_SYMLINK
,
62 void set_de_type(struct f2fs_dir_entry
*de
, struct inode
*inode
)
64 umode_t mode
= inode
->i_mode
;
65 de
->file_type
= f2fs_type_by_mode
[(mode
& S_IFMT
) >> S_SHIFT
];
68 static unsigned long dir_block_index(unsigned int level
,
69 int dir_level
, unsigned int idx
)
72 unsigned long bidx
= 0;
74 for (i
= 0; i
< level
; i
++)
75 bidx
+= dir_buckets(i
, dir_level
) * bucket_blocks(i
);
76 bidx
+= idx
* bucket_blocks(level
);
80 static bool early_match_name(size_t namelen
, f2fs_hash_t namehash
,
81 struct f2fs_dir_entry
*de
)
83 if (le16_to_cpu(de
->name_len
) != namelen
)
86 if (de
->hash_code
!= namehash
)
92 static struct f2fs_dir_entry
*find_in_block(struct page
*dentry_page
,
93 struct qstr
*name
, int *max_slots
,
94 struct page
**res_page
)
96 struct f2fs_dentry_block
*dentry_blk
;
97 struct f2fs_dir_entry
*de
;
99 *max_slots
= NR_DENTRY_IN_BLOCK
;
101 dentry_blk
= (struct f2fs_dentry_block
*)kmap(dentry_page
);
102 de
= find_target_dentry(name
, max_slots
, &dentry_blk
->dentry_bitmap
,
104 dentry_blk
->filename
);
106 *res_page
= dentry_page
;
111 * For the most part, it should be a bug when name_len is zero.
112 * We stop here for figuring out where the bugs has occurred.
114 f2fs_bug_on(F2FS_P_SB(dentry_page
), *max_slots
< 0);
118 struct f2fs_dir_entry
*find_target_dentry(struct qstr
*name
, int *max_slots
,
119 const void *bitmap
, struct f2fs_dir_entry
*dentry
,
120 __u8 (*filenames
)[F2FS_SLOT_LEN
])
122 struct f2fs_dir_entry
*de
;
123 unsigned long bit_pos
= 0;
124 f2fs_hash_t namehash
= f2fs_dentry_hash(name
);
125 int max_bits
= *max_slots
;
129 while (bit_pos
< max_bits
) {
130 if (!test_bit_le(bit_pos
, bitmap
)) {
133 else if (!test_bit_le(bit_pos
- 1, bitmap
))
138 de
= &dentry
[bit_pos
];
139 if (early_match_name(name
->len
, namehash
, de
) &&
140 !memcmp(filenames
[bit_pos
], name
->name
, name
->len
))
143 if (*max_slots
>= 0 && max_len
> *max_slots
) {
144 *max_slots
= max_len
;
148 /* remain bug on condition */
149 if (unlikely(!de
->name_len
))
152 bit_pos
+= GET_DENTRY_SLOTS(le16_to_cpu(de
->name_len
));
157 if (max_len
> *max_slots
)
158 *max_slots
= max_len
;
162 static struct f2fs_dir_entry
*find_in_level(struct inode
*dir
,
163 unsigned int level
, struct qstr
*name
,
164 f2fs_hash_t namehash
, struct page
**res_page
)
166 int s
= GET_DENTRY_SLOTS(name
->len
);
167 unsigned int nbucket
, nblock
;
168 unsigned int bidx
, end_block
;
169 struct page
*dentry_page
;
170 struct f2fs_dir_entry
*de
= NULL
;
174 f2fs_bug_on(F2FS_I_SB(dir
), level
> MAX_DIR_HASH_DEPTH
);
176 nbucket
= dir_buckets(level
, F2FS_I(dir
)->i_dir_level
);
177 nblock
= bucket_blocks(level
);
179 bidx
= dir_block_index(level
, F2FS_I(dir
)->i_dir_level
,
180 le32_to_cpu(namehash
) % nbucket
);
181 end_block
= bidx
+ nblock
;
183 for (; bidx
< end_block
; bidx
++) {
184 /* no need to allocate new dentry pages to all the indices */
185 dentry_page
= find_data_page(dir
, bidx
, true);
186 if (IS_ERR(dentry_page
)) {
191 de
= find_in_block(dentry_page
, name
, &max_slots
, res_page
);
197 f2fs_put_page(dentry_page
, 0);
200 if (!de
&& room
&& F2FS_I(dir
)->chash
!= namehash
) {
201 F2FS_I(dir
)->chash
= namehash
;
202 F2FS_I(dir
)->clevel
= level
;
209 * Find an entry in the specified directory with the wanted name.
210 * It returns the page where the entry was found (as a parameter - res_page),
211 * and the entry itself. Page is returned mapped and unlocked.
212 * Entry is guaranteed to be valid.
214 struct f2fs_dir_entry
*f2fs_find_entry(struct inode
*dir
,
215 struct qstr
*child
, struct page
**res_page
)
217 unsigned long npages
= dir_blocks(dir
);
218 struct f2fs_dir_entry
*de
= NULL
;
219 f2fs_hash_t name_hash
;
220 unsigned int max_depth
;
223 if (f2fs_has_inline_dentry(dir
))
224 return find_in_inline_dir(dir
, child
, res_page
);
231 name_hash
= f2fs_dentry_hash(child
);
232 max_depth
= F2FS_I(dir
)->i_current_depth
;
234 for (level
= 0; level
< max_depth
; level
++) {
235 de
= find_in_level(dir
, level
, child
, name_hash
, res_page
);
239 if (!de
&& F2FS_I(dir
)->chash
!= name_hash
) {
240 F2FS_I(dir
)->chash
= name_hash
;
241 F2FS_I(dir
)->clevel
= level
- 1;
246 struct f2fs_dir_entry
*f2fs_parent_dir(struct inode
*dir
, struct page
**p
)
249 struct f2fs_dir_entry
*de
;
250 struct f2fs_dentry_block
*dentry_blk
;
252 if (f2fs_has_inline_dentry(dir
))
253 return f2fs_parent_inline_dir(dir
, p
);
255 page
= get_lock_data_page(dir
, 0);
259 dentry_blk
= kmap(page
);
260 de
= &dentry_blk
->dentry
[1];
266 ino_t
f2fs_inode_by_name(struct inode
*dir
, struct qstr
*qstr
)
269 struct f2fs_dir_entry
*de
;
272 de
= f2fs_find_entry(dir
, qstr
, &page
);
274 res
= le32_to_cpu(de
->ino
);
275 if (!f2fs_has_inline_dentry(dir
))
277 f2fs_put_page(page
, 0);
283 void f2fs_set_link(struct inode
*dir
, struct f2fs_dir_entry
*de
,
284 struct page
*page
, struct inode
*inode
)
286 enum page_type type
= f2fs_has_inline_dentry(dir
) ? NODE
: DATA
;
288 f2fs_wait_on_page_writeback(page
, type
);
289 de
->ino
= cpu_to_le32(inode
->i_ino
);
290 set_de_type(de
, inode
);
291 if (!f2fs_has_inline_dentry(dir
))
293 set_page_dirty(page
);
294 dir
->i_mtime
= dir
->i_ctime
= CURRENT_TIME
;
295 mark_inode_dirty(dir
);
297 f2fs_put_page(page
, 1);
300 static void init_dent_inode(const struct qstr
*name
, struct page
*ipage
)
302 struct f2fs_inode
*ri
;
304 f2fs_wait_on_page_writeback(ipage
, NODE
);
306 /* copy name info. to this inode page */
307 ri
= F2FS_INODE(ipage
);
308 ri
->i_namelen
= cpu_to_le32(name
->len
);
309 memcpy(ri
->i_name
, name
->name
, name
->len
);
310 set_page_dirty(ipage
);
313 int update_dent_inode(struct inode
*inode
, const struct qstr
*name
)
317 page
= get_node_page(F2FS_I_SB(inode
), inode
->i_ino
);
319 return PTR_ERR(page
);
321 init_dent_inode(name
, page
);
322 f2fs_put_page(page
, 1);
327 static int make_empty_dir(struct inode
*inode
,
328 struct inode
*parent
, struct page
*page
)
330 struct page
*dentry_page
;
331 struct f2fs_dentry_block
*dentry_blk
;
332 struct f2fs_dir_entry
*de
;
334 if (f2fs_has_inline_dentry(inode
))
335 return make_empty_inline_dir(inode
, parent
, page
);
337 dentry_page
= get_new_data_page(inode
, page
, 0, true);
338 if (IS_ERR(dentry_page
))
339 return PTR_ERR(dentry_page
);
341 dentry_blk
= kmap_atomic(dentry_page
);
343 de
= &dentry_blk
->dentry
[0];
344 de
->name_len
= cpu_to_le16(1);
346 de
->ino
= cpu_to_le32(inode
->i_ino
);
347 memcpy(dentry_blk
->filename
[0], ".", 1);
348 set_de_type(de
, inode
);
350 de
= &dentry_blk
->dentry
[1];
352 de
->name_len
= cpu_to_le16(2);
353 de
->ino
= cpu_to_le32(parent
->i_ino
);
354 memcpy(dentry_blk
->filename
[1], "..", 2);
355 set_de_type(de
, inode
);
357 test_and_set_bit_le(0, &dentry_blk
->dentry_bitmap
);
358 test_and_set_bit_le(1, &dentry_blk
->dentry_bitmap
);
359 kunmap_atomic(dentry_blk
);
361 set_page_dirty(dentry_page
);
362 f2fs_put_page(dentry_page
, 1);
366 struct page
*init_inode_metadata(struct inode
*inode
,
367 struct inode
*dir
, const struct qstr
*name
)
372 if (is_inode_flag_set(F2FS_I(inode
), FI_NEW_INODE
)) {
373 page
= new_inode_page(inode
);
377 if (S_ISDIR(inode
->i_mode
)) {
378 err
= make_empty_dir(inode
, dir
, page
);
383 err
= f2fs_init_acl(inode
, dir
, page
);
387 err
= f2fs_init_security(inode
, dir
, name
, page
);
391 page
= get_node_page(F2FS_I_SB(dir
), inode
->i_ino
);
395 set_cold_node(inode
, page
);
399 init_dent_inode(name
, page
);
402 * This file should be checkpointed during fsync.
403 * We lost i_pino from now on.
405 if (is_inode_flag_set(F2FS_I(inode
), FI_INC_LINK
)) {
406 file_lost_pino(inode
);
408 * If link the tmpfile to alias through linkat path,
409 * we should remove this inode from orphan list.
411 if (inode
->i_nlink
== 0)
412 remove_orphan_inode(F2FS_I_SB(dir
), inode
->i_ino
);
418 f2fs_put_page(page
, 1);
420 /* once the failed inode becomes a bad inode, i_mode is S_IFREG */
421 truncate_inode_pages(&inode
->i_data
, 0);
422 truncate_blocks(inode
, 0, false);
423 remove_dirty_dir_inode(inode
);
424 remove_inode_page(inode
);
428 void update_parent_metadata(struct inode
*dir
, struct inode
*inode
,
429 unsigned int current_depth
)
431 if (is_inode_flag_set(F2FS_I(inode
), FI_NEW_INODE
)) {
432 if (S_ISDIR(inode
->i_mode
)) {
434 set_inode_flag(F2FS_I(dir
), FI_UPDATE_DIR
);
436 clear_inode_flag(F2FS_I(inode
), FI_NEW_INODE
);
438 dir
->i_mtime
= dir
->i_ctime
= CURRENT_TIME
;
439 mark_inode_dirty(dir
);
441 if (F2FS_I(dir
)->i_current_depth
!= current_depth
) {
442 F2FS_I(dir
)->i_current_depth
= current_depth
;
443 set_inode_flag(F2FS_I(dir
), FI_UPDATE_DIR
);
446 if (is_inode_flag_set(F2FS_I(inode
), FI_INC_LINK
))
447 clear_inode_flag(F2FS_I(inode
), FI_INC_LINK
);
450 int room_for_filename(const void *bitmap
, int slots
, int max_slots
)
453 int zero_start
, zero_end
;
455 zero_start
= find_next_zero_bit_le(bitmap
, max_slots
, bit_start
);
456 if (zero_start
>= max_slots
)
459 zero_end
= find_next_bit_le(bitmap
, max_slots
, zero_start
);
460 if (zero_end
- zero_start
>= slots
)
463 bit_start
= zero_end
+ 1;
465 if (zero_end
+ 1 >= max_slots
)
471 * Caller should grab and release a rwsem by calling f2fs_lock_op() and
474 int __f2fs_add_link(struct inode
*dir
, const struct qstr
*name
,
477 unsigned int bit_pos
;
479 unsigned int current_depth
;
480 unsigned long bidx
, block
;
481 f2fs_hash_t dentry_hash
;
482 struct f2fs_dir_entry
*de
;
483 unsigned int nbucket
, nblock
;
484 size_t namelen
= name
->len
;
485 struct page
*dentry_page
= NULL
;
486 struct f2fs_dentry_block
*dentry_blk
= NULL
;
487 int slots
= GET_DENTRY_SLOTS(namelen
);
492 if (f2fs_has_inline_dentry(dir
)) {
493 err
= f2fs_add_inline_entry(dir
, name
, inode
);
494 if (!err
|| err
!= -EAGAIN
)
500 dentry_hash
= f2fs_dentry_hash(name
);
502 current_depth
= F2FS_I(dir
)->i_current_depth
;
503 if (F2FS_I(dir
)->chash
== dentry_hash
) {
504 level
= F2FS_I(dir
)->clevel
;
505 F2FS_I(dir
)->chash
= 0;
509 if (unlikely(current_depth
== MAX_DIR_HASH_DEPTH
))
512 /* Increase the depth, if required */
513 if (level
== current_depth
)
516 nbucket
= dir_buckets(level
, F2FS_I(dir
)->i_dir_level
);
517 nblock
= bucket_blocks(level
);
519 bidx
= dir_block_index(level
, F2FS_I(dir
)->i_dir_level
,
520 (le32_to_cpu(dentry_hash
) % nbucket
));
522 for (block
= bidx
; block
<= (bidx
+ nblock
- 1); block
++) {
523 dentry_page
= get_new_data_page(dir
, NULL
, block
, true);
524 if (IS_ERR(dentry_page
))
525 return PTR_ERR(dentry_page
);
527 dentry_blk
= kmap(dentry_page
);
528 bit_pos
= room_for_filename(&dentry_blk
->dentry_bitmap
,
529 slots
, NR_DENTRY_IN_BLOCK
);
530 if (bit_pos
< NR_DENTRY_IN_BLOCK
)
534 f2fs_put_page(dentry_page
, 1);
537 /* Move to next level to find the empty slot for new dentry */
541 f2fs_wait_on_page_writeback(dentry_page
, DATA
);
543 down_write(&F2FS_I(inode
)->i_sem
);
544 page
= init_inode_metadata(inode
, dir
, name
);
549 de
= &dentry_blk
->dentry
[bit_pos
];
550 de
->hash_code
= dentry_hash
;
551 de
->name_len
= cpu_to_le16(namelen
);
552 memcpy(dentry_blk
->filename
[bit_pos
], name
->name
, name
->len
);
553 de
->ino
= cpu_to_le32(inode
->i_ino
);
554 set_de_type(de
, inode
);
555 for (i
= 0; i
< slots
; i
++)
556 test_and_set_bit_le(bit_pos
+ i
, &dentry_blk
->dentry_bitmap
);
557 set_page_dirty(dentry_page
);
559 /* we don't need to mark_inode_dirty now */
560 F2FS_I(inode
)->i_pino
= dir
->i_ino
;
561 update_inode(inode
, page
);
562 f2fs_put_page(page
, 1);
564 update_parent_metadata(dir
, inode
, current_depth
);
566 up_write(&F2FS_I(inode
)->i_sem
);
568 if (is_inode_flag_set(F2FS_I(dir
), FI_UPDATE_DIR
)) {
569 update_inode_page(dir
);
570 clear_inode_flag(F2FS_I(dir
), FI_UPDATE_DIR
);
573 f2fs_put_page(dentry_page
, 1);
577 int f2fs_do_tmpfile(struct inode
*inode
, struct inode
*dir
)
582 down_write(&F2FS_I(inode
)->i_sem
);
583 page
= init_inode_metadata(inode
, dir
, NULL
);
588 /* we don't need to mark_inode_dirty now */
589 update_inode(inode
, page
);
590 f2fs_put_page(page
, 1);
592 clear_inode_flag(F2FS_I(inode
), FI_NEW_INODE
);
594 up_write(&F2FS_I(inode
)->i_sem
);
598 void f2fs_drop_nlink(struct inode
*dir
, struct inode
*inode
, struct page
*page
)
600 struct f2fs_sb_info
*sbi
= F2FS_I_SB(dir
);
602 down_write(&F2FS_I(inode
)->i_sem
);
604 if (S_ISDIR(inode
->i_mode
)) {
607 update_inode(dir
, page
);
609 update_inode_page(dir
);
611 inode
->i_ctime
= CURRENT_TIME
;
614 if (S_ISDIR(inode
->i_mode
)) {
616 i_size_write(inode
, 0);
618 up_write(&F2FS_I(inode
)->i_sem
);
619 update_inode_page(inode
);
621 if (inode
->i_nlink
== 0)
622 add_orphan_inode(sbi
, inode
->i_ino
);
624 release_orphan_inode(sbi
);
628 * It only removes the dentry from the dentry page, corresponding name
629 * entry in name page does not need to be touched during deletion.
631 void f2fs_delete_entry(struct f2fs_dir_entry
*dentry
, struct page
*page
,
632 struct inode
*dir
, struct inode
*inode
)
634 struct f2fs_dentry_block
*dentry_blk
;
635 unsigned int bit_pos
;
636 int slots
= GET_DENTRY_SLOTS(le16_to_cpu(dentry
->name_len
));
639 if (f2fs_has_inline_dentry(dir
))
640 return f2fs_delete_inline_entry(dentry
, page
, dir
, inode
);
643 f2fs_wait_on_page_writeback(page
, DATA
);
645 dentry_blk
= page_address(page
);
646 bit_pos
= dentry
- dentry_blk
->dentry
;
647 for (i
= 0; i
< slots
; i
++)
648 test_and_clear_bit_le(bit_pos
+ i
, &dentry_blk
->dentry_bitmap
);
650 /* Let's check and deallocate this dentry page */
651 bit_pos
= find_next_bit_le(&dentry_blk
->dentry_bitmap
,
654 kunmap(page
); /* kunmap - pair of f2fs_find_entry */
655 set_page_dirty(page
);
657 dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
660 f2fs_drop_nlink(dir
, inode
, NULL
);
662 if (bit_pos
== NR_DENTRY_IN_BLOCK
) {
663 truncate_hole(dir
, page
->index
, page
->index
+ 1);
664 clear_page_dirty_for_io(page
);
665 ClearPageUptodate(page
);
666 inode_dec_dirty_pages(dir
);
668 f2fs_put_page(page
, 1);
671 bool f2fs_empty_dir(struct inode
*dir
)
674 struct page
*dentry_page
;
675 unsigned int bit_pos
;
676 struct f2fs_dentry_block
*dentry_blk
;
677 unsigned long nblock
= dir_blocks(dir
);
679 if (f2fs_has_inline_dentry(dir
))
680 return f2fs_empty_inline_dir(dir
);
682 for (bidx
= 0; bidx
< nblock
; bidx
++) {
683 dentry_page
= get_lock_data_page(dir
, bidx
);
684 if (IS_ERR(dentry_page
)) {
685 if (PTR_ERR(dentry_page
) == -ENOENT
)
691 dentry_blk
= kmap_atomic(dentry_page
);
696 bit_pos
= find_next_bit_le(&dentry_blk
->dentry_bitmap
,
699 kunmap_atomic(dentry_blk
);
701 f2fs_put_page(dentry_page
, 1);
703 if (bit_pos
< NR_DENTRY_IN_BLOCK
)
709 static int f2fs_readdir(struct file
*file
, struct dir_context
*ctx
)
711 struct inode
*inode
= file_inode(file
);
712 unsigned long npages
= dir_blocks(inode
);
713 unsigned int bit_pos
= 0;
714 struct f2fs_dentry_block
*dentry_blk
= NULL
;
715 struct f2fs_dir_entry
*de
= NULL
;
716 struct page
*dentry_page
= NULL
;
717 struct file_ra_state
*ra
= &file
->f_ra
;
718 unsigned int n
= ((unsigned long)ctx
->pos
/ NR_DENTRY_IN_BLOCK
);
719 unsigned char d_type
= DT_UNKNOWN
;
721 if (f2fs_has_inline_dentry(inode
))
722 return f2fs_read_inline_dir(file
, ctx
);
724 bit_pos
= ((unsigned long)ctx
->pos
% NR_DENTRY_IN_BLOCK
);
726 /* readahead for multi pages of dir */
727 if (npages
- n
> 1 && !ra_has_index(ra
, n
))
728 page_cache_sync_readahead(inode
->i_mapping
, ra
, file
, n
,
729 min(npages
- n
, (pgoff_t
)MAX_DIR_RA_PAGES
));
731 for (; n
< npages
; n
++) {
732 dentry_page
= get_lock_data_page(inode
, n
);
733 if (IS_ERR(dentry_page
))
736 dentry_blk
= kmap(dentry_page
);
737 while (bit_pos
< NR_DENTRY_IN_BLOCK
) {
738 bit_pos
= find_next_bit_le(&dentry_blk
->dentry_bitmap
,
741 if (bit_pos
>= NR_DENTRY_IN_BLOCK
)
744 de
= &dentry_blk
->dentry
[bit_pos
];
745 if (de
->file_type
< F2FS_FT_MAX
)
746 d_type
= f2fs_filetype_table
[de
->file_type
];
750 dentry_blk
->filename
[bit_pos
],
751 le16_to_cpu(de
->name_len
),
752 le32_to_cpu(de
->ino
), d_type
))
755 bit_pos
+= GET_DENTRY_SLOTS(le16_to_cpu(de
->name_len
));
756 ctx
->pos
= n
* NR_DENTRY_IN_BLOCK
+ bit_pos
;
759 ctx
->pos
= (n
+ 1) * NR_DENTRY_IN_BLOCK
;
761 f2fs_put_page(dentry_page
, 1);
765 if (dentry_page
&& !IS_ERR(dentry_page
)) {
767 f2fs_put_page(dentry_page
, 1);
773 const struct file_operations f2fs_dir_operations
= {
774 .llseek
= generic_file_llseek
,
775 .read
= generic_read_dir
,
776 .iterate
= f2fs_readdir
,
777 .fsync
= f2fs_sync_file
,
778 .unlocked_ioctl
= f2fs_ioctl
,