1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Copyright (C) 2016 - 2020 Christoph Hellwig
6 */
7 #include <linux/init.h>
8 #include <linux/mm.h>
9 #include <linux/blkdev.h>
10 #include <linux/buffer_head.h>
11 #include <linux/mpage.h>
12 #include <linux/uio.h>
13 #include <linux/namei.h>
14 #include <linux/task_io_accounting_ops.h>
15 #include <linux/falloc.h>
16 #include <linux/suspend.h>
17 #include <linux/fs.h>
18 #include "blk.h"
19
bdev_file_inode(struct file * file)20 static struct inode *bdev_file_inode(struct file *file)
21 {
22 return file->f_mapping->host;
23 }
24
blkdev_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)25 static int blkdev_get_block(struct inode *inode, sector_t iblock,
26 struct buffer_head *bh, int create)
27 {
28 bh->b_bdev = I_BDEV(inode);
29 bh->b_blocknr = iblock;
30 set_buffer_mapped(bh);
31 return 0;
32 }
33
dio_bio_write_op(struct kiocb * iocb)34 static unsigned int dio_bio_write_op(struct kiocb *iocb)
35 {
36 unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
37
38 /* avoid the need for a I/O completion work item */
39 if (iocb->ki_flags & IOCB_DSYNC)
40 op |= REQ_FUA;
41 return op;
42 }
43
44 #define DIO_INLINE_BIO_VECS 4
45
blkdev_bio_end_io_simple(struct bio * bio)46 static void blkdev_bio_end_io_simple(struct bio *bio)
47 {
48 struct task_struct *waiter = bio->bi_private;
49
50 WRITE_ONCE(bio->bi_private, NULL);
51 blk_wake_io_task(waiter);
52 }
53
__blkdev_direct_IO_simple(struct kiocb * iocb,struct iov_iter * iter,unsigned int nr_pages)54 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
55 struct iov_iter *iter, unsigned int nr_pages)
56 {
57 struct file *file = iocb->ki_filp;
58 struct block_device *bdev = I_BDEV(bdev_file_inode(file));
59 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
60 loff_t pos = iocb->ki_pos;
61 bool should_dirty = false;
62 struct bio bio;
63 ssize_t ret;
64 blk_qc_t qc;
65
66 if ((pos | iov_iter_alignment(iter)) &
67 (bdev_logical_block_size(bdev) - 1))
68 return -EINVAL;
69
70 if (nr_pages <= DIO_INLINE_BIO_VECS)
71 vecs = inline_vecs;
72 else {
73 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
74 GFP_KERNEL);
75 if (!vecs)
76 return -ENOMEM;
77 }
78
79 bio_init(&bio, vecs, nr_pages);
80 bio_set_dev(&bio, bdev);
81 bio.bi_iter.bi_sector = pos >> 9;
82 bio.bi_write_hint = iocb->ki_hint;
83 bio.bi_private = current;
84 bio.bi_end_io = blkdev_bio_end_io_simple;
85 bio.bi_ioprio = iocb->ki_ioprio;
86
87 ret = bio_iov_iter_get_pages(&bio, iter);
88 if (unlikely(ret))
89 goto out;
90 ret = bio.bi_iter.bi_size;
91
92 if (iov_iter_rw(iter) == READ) {
93 bio.bi_opf = REQ_OP_READ;
94 if (iter_is_iovec(iter))
95 should_dirty = true;
96 } else {
97 bio.bi_opf = dio_bio_write_op(iocb);
98 task_io_account_write(ret);
99 }
100 if (iocb->ki_flags & IOCB_NOWAIT)
101 bio.bi_opf |= REQ_NOWAIT;
102 if (iocb->ki_flags & IOCB_HIPRI)
103 bio_set_polled(&bio, iocb);
104
105 qc = submit_bio(&bio);
106 for (;;) {
107 set_current_state(TASK_UNINTERRUPTIBLE);
108 if (!READ_ONCE(bio.bi_private))
109 break;
110 if (!(iocb->ki_flags & IOCB_HIPRI) ||
111 !blk_poll(bdev_get_queue(bdev), qc, true))
112 blk_io_schedule();
113 }
114 __set_current_state(TASK_RUNNING);
115
116 bio_release_pages(&bio, should_dirty);
117 if (unlikely(bio.bi_status))
118 ret = blk_status_to_errno(bio.bi_status);
119
120 out:
121 if (vecs != inline_vecs)
122 kfree(vecs);
123
124 bio_uninit(&bio);
125
126 return ret;
127 }
128
129 struct blkdev_dio {
130 union {
131 struct kiocb *iocb;
132 struct task_struct *waiter;
133 };
134 size_t size;
135 atomic_t ref;
136 bool multi_bio : 1;
137 bool should_dirty : 1;
138 bool is_sync : 1;
139 struct bio bio;
140 };
141
142 static struct bio_set blkdev_dio_pool;
143
blkdev_iopoll(struct kiocb * kiocb,bool wait)144 static int blkdev_iopoll(struct kiocb *kiocb, bool wait)
145 {
146 struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host);
147 struct request_queue *q = bdev_get_queue(bdev);
148
149 return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait);
150 }
151
blkdev_bio_end_io(struct bio * bio)152 static void blkdev_bio_end_io(struct bio *bio)
153 {
154 struct blkdev_dio *dio = bio->bi_private;
155 bool should_dirty = dio->should_dirty;
156
157 if (bio->bi_status && !dio->bio.bi_status)
158 dio->bio.bi_status = bio->bi_status;
159
160 if (!dio->multi_bio || atomic_dec_and_test(&dio->ref)) {
161 if (!dio->is_sync) {
162 struct kiocb *iocb = dio->iocb;
163 ssize_t ret;
164
165 if (likely(!dio->bio.bi_status)) {
166 ret = dio->size;
167 iocb->ki_pos += ret;
168 } else {
169 ret = blk_status_to_errno(dio->bio.bi_status);
170 }
171
172 dio->iocb->ki_complete(iocb, ret, 0);
173 if (dio->multi_bio)
174 bio_put(&dio->bio);
175 } else {
176 struct task_struct *waiter = dio->waiter;
177
178 WRITE_ONCE(dio->waiter, NULL);
179 blk_wake_io_task(waiter);
180 }
181 }
182
183 if (should_dirty) {
184 bio_check_pages_dirty(bio);
185 } else {
186 bio_release_pages(bio, false);
187 bio_put(bio);
188 }
189 }
190
__blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter,unsigned int nr_pages)191 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
192 unsigned int nr_pages)
193 {
194 struct file *file = iocb->ki_filp;
195 struct inode *inode = bdev_file_inode(file);
196 struct block_device *bdev = I_BDEV(inode);
197 struct blk_plug plug;
198 struct blkdev_dio *dio;
199 struct bio *bio;
200 bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
201 bool is_read = (iov_iter_rw(iter) == READ), is_sync;
202 loff_t pos = iocb->ki_pos;
203 blk_qc_t qc = BLK_QC_T_NONE;
204 int ret = 0;
205
206 if ((pos | iov_iter_alignment(iter)) &
207 (bdev_logical_block_size(bdev) - 1))
208 return -EINVAL;
209
210 bio = bio_alloc_kiocb(iocb, nr_pages, &blkdev_dio_pool);
211
212 dio = container_of(bio, struct blkdev_dio, bio);
213 dio->is_sync = is_sync = is_sync_kiocb(iocb);
214 if (dio->is_sync) {
215 dio->waiter = current;
216 bio_get(bio);
217 } else {
218 dio->iocb = iocb;
219 }
220
221 dio->size = 0;
222 dio->multi_bio = false;
223 dio->should_dirty = is_read && iter_is_iovec(iter);
224
225 /*
226 * Don't plug for HIPRI/polled IO, as those should go straight
227 * to issue
228 */
229 if (!is_poll)
230 blk_start_plug(&plug);
231
232 for (;;) {
233 bio_set_dev(bio, bdev);
234 bio->bi_iter.bi_sector = pos >> 9;
235 bio->bi_write_hint = iocb->ki_hint;
236 bio->bi_private = dio;
237 bio->bi_end_io = blkdev_bio_end_io;
238 bio->bi_ioprio = iocb->ki_ioprio;
239
240 ret = bio_iov_iter_get_pages(bio, iter);
241 if (unlikely(ret)) {
242 bio->bi_status = BLK_STS_IOERR;
243 bio_endio(bio);
244 break;
245 }
246
247 if (is_read) {
248 bio->bi_opf = REQ_OP_READ;
249 if (dio->should_dirty)
250 bio_set_pages_dirty(bio);
251 } else {
252 bio->bi_opf = dio_bio_write_op(iocb);
253 task_io_account_write(bio->bi_iter.bi_size);
254 }
255 if (iocb->ki_flags & IOCB_NOWAIT)
256 bio->bi_opf |= REQ_NOWAIT;
257
258 dio->size += bio->bi_iter.bi_size;
259 pos += bio->bi_iter.bi_size;
260
261 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
262 if (!nr_pages) {
263 bool polled = false;
264
265 if (iocb->ki_flags & IOCB_HIPRI) {
266 bio_set_polled(bio, iocb);
267 polled = true;
268 }
269
270 qc = submit_bio(bio);
271
272 if (polled)
273 WRITE_ONCE(iocb->ki_cookie, qc);
274 break;
275 }
276
277 if (!dio->multi_bio) {
278 /*
279 * AIO needs an extra reference to ensure the dio
280 * structure which is embedded into the first bio
281 * stays around.
282 */
283 if (!is_sync)
284 bio_get(bio);
285 dio->multi_bio = true;
286 atomic_set(&dio->ref, 2);
287 } else {
288 atomic_inc(&dio->ref);
289 }
290
291 submit_bio(bio);
292 bio = bio_alloc(GFP_KERNEL, nr_pages);
293 }
294
295 if (!is_poll)
296 blk_finish_plug(&plug);
297
298 if (!is_sync)
299 return -EIOCBQUEUED;
300
301 for (;;) {
302 set_current_state(TASK_UNINTERRUPTIBLE);
303 if (!READ_ONCE(dio->waiter))
304 break;
305
306 if (!(iocb->ki_flags & IOCB_HIPRI) ||
307 !blk_poll(bdev_get_queue(bdev), qc, true))
308 blk_io_schedule();
309 }
310 __set_current_state(TASK_RUNNING);
311
312 if (!ret)
313 ret = blk_status_to_errno(dio->bio.bi_status);
314 if (likely(!ret))
315 ret = dio->size;
316
317 bio_put(&dio->bio);
318 return ret;
319 }
320
blkdev_direct_IO(struct kiocb * iocb,struct iov_iter * iter)321 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
322 {
323 unsigned int nr_pages;
324
325 if (!iov_iter_count(iter))
326 return 0;
327
328 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
329 if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_VECS)
330 return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
331
332 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
333 }
334
blkdev_writepage(struct page * page,struct writeback_control * wbc)335 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
336 {
337 return block_write_full_page(page, blkdev_get_block, wbc);
338 }
339
blkdev_readpage(struct file * file,struct page * page)340 static int blkdev_readpage(struct file * file, struct page * page)
341 {
342 return block_read_full_page(page, blkdev_get_block);
343 }
344
blkdev_readahead(struct readahead_control * rac)345 static void blkdev_readahead(struct readahead_control *rac)
346 {
347 mpage_readahead(rac, blkdev_get_block);
348 }
349
blkdev_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)350 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
351 loff_t pos, unsigned len, unsigned flags, struct page **pagep,
352 void **fsdata)
353 {
354 return block_write_begin(mapping, pos, len, flags, pagep,
355 blkdev_get_block);
356 }
357
blkdev_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)358 static int blkdev_write_end(struct file *file, struct address_space *mapping,
359 loff_t pos, unsigned len, unsigned copied, struct page *page,
360 void *fsdata)
361 {
362 int ret;
363 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
364
365 unlock_page(page);
366 put_page(page);
367
368 return ret;
369 }
370
blkdev_writepages(struct address_space * mapping,struct writeback_control * wbc)371 static int blkdev_writepages(struct address_space *mapping,
372 struct writeback_control *wbc)
373 {
374 return generic_writepages(mapping, wbc);
375 }
376
377 const struct address_space_operations def_blk_aops = {
378 .set_page_dirty = __set_page_dirty_buffers,
379 .readpage = blkdev_readpage,
380 .readahead = blkdev_readahead,
381 .writepage = blkdev_writepage,
382 .write_begin = blkdev_write_begin,
383 .write_end = blkdev_write_end,
384 .writepages = blkdev_writepages,
385 .direct_IO = blkdev_direct_IO,
386 .migratepage = buffer_migrate_page_norefs,
387 .is_dirty_writeback = buffer_check_dirty_writeback,
388 };
389
390 /*
391 * for a block special file file_inode(file)->i_size is zero
392 * so we compute the size by hand (just as in block_read/write above)
393 */
blkdev_llseek(struct file * file,loff_t offset,int whence)394 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
395 {
396 struct inode *bd_inode = bdev_file_inode(file);
397 loff_t retval;
398
399 inode_lock(bd_inode);
400 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
401 inode_unlock(bd_inode);
402 return retval;
403 }
404
blkdev_fsync(struct file * filp,loff_t start,loff_t end,int datasync)405 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
406 int datasync)
407 {
408 struct inode *bd_inode = bdev_file_inode(filp);
409 struct block_device *bdev = I_BDEV(bd_inode);
410 int error;
411
412 error = file_write_and_wait_range(filp, start, end);
413 if (error)
414 return error;
415
416 /*
417 * There is no need to serialise calls to blkdev_issue_flush with
418 * i_mutex and doing so causes performance issues with concurrent
419 * O_SYNC writers to a block device.
420 */
421 error = blkdev_issue_flush(bdev);
422 if (error == -EOPNOTSUPP)
423 error = 0;
424
425 return error;
426 }
427
blkdev_open(struct inode * inode,struct file * filp)428 static int blkdev_open(struct inode *inode, struct file *filp)
429 {
430 struct block_device *bdev;
431
432 /*
433 * Preserve backwards compatibility and allow large file access
434 * even if userspace doesn't ask for it explicitly. Some mkfs
435 * binary needs it. We might want to drop this workaround
436 * during an unstable branch.
437 */
438 filp->f_flags |= O_LARGEFILE;
439 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
440
441 if (filp->f_flags & O_NDELAY)
442 filp->f_mode |= FMODE_NDELAY;
443 if (filp->f_flags & O_EXCL)
444 filp->f_mode |= FMODE_EXCL;
445 if ((filp->f_flags & O_ACCMODE) == 3)
446 filp->f_mode |= FMODE_WRITE_IOCTL;
447
448 bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
449 if (IS_ERR(bdev))
450 return PTR_ERR(bdev);
451 filp->f_mapping = bdev->bd_inode->i_mapping;
452 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
453 return 0;
454 }
455
blkdev_close(struct inode * inode,struct file * filp)456 static int blkdev_close(struct inode *inode, struct file *filp)
457 {
458 struct block_device *bdev = I_BDEV(bdev_file_inode(filp));
459
460 blkdev_put(bdev, filp->f_mode);
461 return 0;
462 }
463
block_ioctl(struct file * file,unsigned cmd,unsigned long arg)464 static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
465 {
466 struct block_device *bdev = I_BDEV(bdev_file_inode(file));
467 fmode_t mode = file->f_mode;
468
469 /*
470 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
471 * to updated it before every ioctl.
472 */
473 if (file->f_flags & O_NDELAY)
474 mode |= FMODE_NDELAY;
475 else
476 mode &= ~FMODE_NDELAY;
477
478 return blkdev_ioctl(bdev, mode, cmd, arg);
479 }
480
481 /*
482 * Write data to the block device. Only intended for the block device itself
483 * and the raw driver which basically is a fake block device.
484 *
485 * Does not take i_mutex for the write and thus is not for general purpose
486 * use.
487 */
blkdev_write_iter(struct kiocb * iocb,struct iov_iter * from)488 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
489 {
490 struct file *file = iocb->ki_filp;
491 struct inode *bd_inode = bdev_file_inode(file);
492 loff_t size = i_size_read(bd_inode);
493 struct blk_plug plug;
494 size_t shorted = 0;
495 ssize_t ret;
496
497 if (bdev_read_only(I_BDEV(bd_inode)))
498 return -EPERM;
499
500 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
501 return -ETXTBSY;
502
503 if (!iov_iter_count(from))
504 return 0;
505
506 if (iocb->ki_pos >= size)
507 return -ENOSPC;
508
509 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
510 return -EOPNOTSUPP;
511
512 size -= iocb->ki_pos;
513 if (iov_iter_count(from) > size) {
514 shorted = iov_iter_count(from) - size;
515 iov_iter_truncate(from, size);
516 }
517
518 blk_start_plug(&plug);
519 ret = __generic_file_write_iter(iocb, from);
520 if (ret > 0)
521 ret = generic_write_sync(iocb, ret);
522 iov_iter_reexpand(from, iov_iter_count(from) + shorted);
523 blk_finish_plug(&plug);
524 return ret;
525 }
526
blkdev_read_iter(struct kiocb * iocb,struct iov_iter * to)527 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
528 {
529 struct file *file = iocb->ki_filp;
530 struct inode *bd_inode = bdev_file_inode(file);
531 loff_t size = i_size_read(bd_inode);
532 loff_t pos = iocb->ki_pos;
533 size_t shorted = 0;
534 ssize_t ret;
535
536 if (pos >= size)
537 return 0;
538
539 size -= pos;
540 if (iov_iter_count(to) > size) {
541 shorted = iov_iter_count(to) - size;
542 iov_iter_truncate(to, size);
543 }
544
545 ret = generic_file_read_iter(iocb, to);
546 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
547 return ret;
548 }
549
550 #define BLKDEV_FALLOC_FL_SUPPORTED \
551 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
552 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
553
blkdev_fallocate(struct file * file,int mode,loff_t start,loff_t len)554 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
555 loff_t len)
556 {
557 struct inode *inode = bdev_file_inode(file);
558 struct block_device *bdev = I_BDEV(inode);
559 loff_t end = start + len - 1;
560 loff_t isize;
561 int error;
562
563 /* Fail if we don't recognize the flags. */
564 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
565 return -EOPNOTSUPP;
566
567 /* Don't go off the end of the device. */
568 isize = i_size_read(bdev->bd_inode);
569 if (start >= isize)
570 return -EINVAL;
571 if (end >= isize) {
572 if (mode & FALLOC_FL_KEEP_SIZE) {
573 len = isize - start;
574 end = start + len - 1;
575 } else
576 return -EINVAL;
577 }
578
579 /*
580 * Don't allow IO that isn't aligned to logical block size.
581 */
582 if ((start | len) & (bdev_logical_block_size(bdev) - 1))
583 return -EINVAL;
584
585 filemap_invalidate_lock(inode->i_mapping);
586
587 /* Invalidate the page cache, including dirty pages. */
588 error = truncate_bdev_range(bdev, file->f_mode, start, end);
589 if (error)
590 goto fail;
591
592 switch (mode) {
593 case FALLOC_FL_ZERO_RANGE:
594 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
595 error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9,
596 GFP_KERNEL, BLKDEV_ZERO_NOUNMAP);
597 break;
598 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
599 error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9,
600 GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK);
601 break;
602 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
603 error = blkdev_issue_discard(bdev, start >> 9, len >> 9,
604 GFP_KERNEL, 0);
605 break;
606 default:
607 error = -EOPNOTSUPP;
608 }
609
610 fail:
611 filemap_invalidate_unlock(inode->i_mapping);
612 return error;
613 }
614
615 const struct file_operations def_blk_fops = {
616 .open = blkdev_open,
617 .release = blkdev_close,
618 .llseek = blkdev_llseek,
619 .read_iter = blkdev_read_iter,
620 .write_iter = blkdev_write_iter,
621 .iopoll = blkdev_iopoll,
622 .mmap = generic_file_mmap,
623 .fsync = blkdev_fsync,
624 .unlocked_ioctl = block_ioctl,
625 #ifdef CONFIG_COMPAT
626 .compat_ioctl = compat_blkdev_ioctl,
627 #endif
628 .splice_read = generic_file_splice_read,
629 .splice_write = iter_file_splice_write,
630 .fallocate = blkdev_fallocate,
631 };
632
blkdev_init(void)633 static __init int blkdev_init(void)
634 {
635 return bioset_init(&blkdev_dio_pool, 4,
636 offsetof(struct blkdev_dio, bio),
637 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
638 }
639 module_init(blkdev_init);
640
