Line data Source code
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 :
8 : #include <linux/init.h>
9 : #include <linux/mm.h>
10 : #include <linux/fcntl.h>
11 : #include <linux/slab.h>
12 : #include <linux/kmod.h>
13 : #include <linux/major.h>
14 : #include <linux/device_cgroup.h>
15 : #include <linux/highmem.h>
16 : #include <linux/blkdev.h>
17 : #include <linux/backing-dev.h>
18 : #include <linux/module.h>
19 : #include <linux/blkpg.h>
20 : #include <linux/magic.h>
21 : #include <linux/buffer_head.h>
22 : #include <linux/swap.h>
23 : #include <linux/pagevec.h>
24 : #include <linux/writeback.h>
25 : #include <linux/mpage.h>
26 : #include <linux/mount.h>
27 : #include <linux/pseudo_fs.h>
28 : #include <linux/uio.h>
29 : #include <linux/namei.h>
30 : #include <linux/log2.h>
31 : #include <linux/cleancache.h>
32 : #include <linux/task_io_accounting_ops.h>
33 : #include <linux/falloc.h>
34 : #include <linux/part_stat.h>
35 : #include <linux/uaccess.h>
36 : #include <linux/suspend.h>
37 : #include "internal.h"
38 :
39 : struct bdev_inode {
40 : struct block_device bdev;
41 : struct inode vfs_inode;
42 : };
43 :
44 : static const struct address_space_operations def_blk_aops;
45 :
46 12398 : static inline struct bdev_inode *BDEV_I(struct inode *inode)
47 : {
48 12398 : return container_of(inode, struct bdev_inode, vfs_inode);
49 : }
50 :
51 12363 : struct block_device *I_BDEV(struct inode *inode)
52 : {
53 12363 : return &BDEV_I(inode)->bdev;
54 : }
55 : EXPORT_SYMBOL(I_BDEV);
56 :
57 11 : static void bdev_write_inode(struct block_device *bdev)
58 : {
59 11 : struct inode *inode = bdev->bd_inode;
60 11 : int ret;
61 :
62 11 : spin_lock(&inode->i_lock);
63 11 : while (inode->i_state & I_DIRTY) {
64 0 : spin_unlock(&inode->i_lock);
65 0 : ret = write_inode_now(inode, true);
66 0 : if (ret) {
67 0 : char name[BDEVNAME_SIZE];
68 0 : pr_warn_ratelimited("VFS: Dirty inode writeback failed "
69 : "for block device %s (err=%d).\n",
70 : bdevname(bdev, name), ret);
71 : }
72 11 : spin_lock(&inode->i_lock);
73 : }
74 11 : spin_unlock(&inode->i_lock);
75 11 : }
76 :
77 : /* Kill _all_ buffers and pagecache , dirty or not.. */
78 14 : static void kill_bdev(struct block_device *bdev)
79 : {
80 14 : struct address_space *mapping = bdev->bd_inode->i_mapping;
81 :
82 14 : if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
83 : return;
84 :
85 3 : invalidate_bh_lrus();
86 3 : truncate_inode_pages(mapping, 0);
87 : }
88 :
89 : /* Invalidate clean unused buffers and pagecache. */
90 1 : void invalidate_bdev(struct block_device *bdev)
91 : {
92 1 : struct address_space *mapping = bdev->bd_inode->i_mapping;
93 :
94 1 : if (mapping->nrpages) {
95 0 : invalidate_bh_lrus();
96 0 : lru_add_drain_all(); /* make sure all lru add caches are flushed */
97 0 : invalidate_mapping_pages(mapping, 0, -1);
98 : }
99 : /* 99% of the time, we don't need to flush the cleancache on the bdev.
100 : * But, for the strange corners, lets be cautious
101 : */
102 1 : cleancache_invalidate_inode(mapping);
103 1 : }
104 : EXPORT_SYMBOL(invalidate_bdev);
105 :
106 : /*
107 : * Drop all buffers & page cache for given bdev range. This function bails
108 : * with error if bdev has other exclusive owner (such as filesystem).
109 : */
110 0 : int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
111 : loff_t lstart, loff_t lend)
112 : {
113 : /*
114 : * If we don't hold exclusive handle for the device, upgrade to it
115 : * while we discard the buffer cache to avoid discarding buffers
116 : * under live filesystem.
117 : */
118 0 : if (!(mode & FMODE_EXCL)) {
119 0 : int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
120 0 : if (err)
121 0 : goto invalidate;
122 : }
123 :
124 0 : truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
125 0 : if (!(mode & FMODE_EXCL))
126 0 : bd_abort_claiming(bdev, truncate_bdev_range);
127 : return 0;
128 :
129 0 : invalidate:
130 : /*
131 : * Someone else has handle exclusively open. Try invalidating instead.
132 : * The 'end' argument is inclusive so the rounding is safe.
133 : */
134 0 : return invalidate_inode_pages2_range(bdev->bd_inode->i_mapping,
135 0 : lstart >> PAGE_SHIFT,
136 0 : lend >> PAGE_SHIFT);
137 : }
138 :
139 13 : static void set_init_blocksize(struct block_device *bdev)
140 : {
141 13 : unsigned int bsize = bdev_logical_block_size(bdev);
142 13 : loff_t size = i_size_read(bdev->bd_inode);
143 :
144 52 : while (bsize < PAGE_SIZE) {
145 39 : if (size & bsize)
146 : break;
147 39 : bsize <<= 1;
148 : }
149 13 : bdev->bd_inode->i_blkbits = blksize_bits(bsize);
150 13 : }
151 :
152 5 : int set_blocksize(struct block_device *bdev, int size)
153 : {
154 : /* Size must be a power of two, and between 512 and PAGE_SIZE */
155 5 : if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
156 : return -EINVAL;
157 :
158 : /* Size cannot be smaller than the size supported by the device */
159 10 : if (size < bdev_logical_block_size(bdev))
160 : return -EINVAL;
161 :
162 : /* Don't change the size if it is same as current */
163 10 : if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
164 3 : sync_blockdev(bdev);
165 6 : bdev->bd_inode->i_blkbits = blksize_bits(size);
166 3 : kill_bdev(bdev);
167 : }
168 : return 0;
169 : }
170 :
171 : EXPORT_SYMBOL(set_blocksize);
172 :
173 5 : int sb_set_blocksize(struct super_block *sb, int size)
174 : {
175 5 : if (set_blocksize(sb->s_bdev, size))
176 : return 0;
177 : /* If we get here, we know size is power of two
178 : * and it's value is between 512 and PAGE_SIZE */
179 5 : sb->s_blocksize = size;
180 5 : sb->s_blocksize_bits = blksize_bits(size);
181 5 : return sb->s_blocksize;
182 : }
183 :
184 : EXPORT_SYMBOL(sb_set_blocksize);
185 :
186 2 : int sb_min_blocksize(struct super_block *sb, int size)
187 : {
188 2 : int minsize = bdev_logical_block_size(sb->s_bdev);
189 2 : if (size < minsize)
190 : size = minsize;
191 2 : return sb_set_blocksize(sb, size);
192 : }
193 :
194 : EXPORT_SYMBOL(sb_min_blocksize);
195 :
196 : static int
197 73 : blkdev_get_block(struct inode *inode, sector_t iblock,
198 : struct buffer_head *bh, int create)
199 : {
200 73 : bh->b_bdev = I_BDEV(inode);
201 73 : bh->b_blocknr = iblock;
202 73 : set_buffer_mapped(bh);
203 73 : return 0;
204 : }
205 :
206 427 : static struct inode *bdev_file_inode(struct file *file)
207 : {
208 427 : return file->f_mapping->host;
209 : }
210 :
211 0 : static unsigned int dio_bio_write_op(struct kiocb *iocb)
212 : {
213 0 : unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
214 :
215 : /* avoid the need for a I/O completion work item */
216 0 : if (iocb->ki_flags & IOCB_DSYNC)
217 0 : op |= REQ_FUA;
218 0 : return op;
219 : }
220 :
221 : #define DIO_INLINE_BIO_VECS 4
222 :
223 0 : static void blkdev_bio_end_io_simple(struct bio *bio)
224 : {
225 0 : struct task_struct *waiter = bio->bi_private;
226 :
227 0 : WRITE_ONCE(bio->bi_private, NULL);
228 0 : blk_wake_io_task(waiter);
229 0 : }
230 :
231 : static ssize_t
232 0 : __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
233 : unsigned int nr_pages)
234 : {
235 0 : struct file *file = iocb->ki_filp;
236 0 : struct block_device *bdev = I_BDEV(bdev_file_inode(file));
237 0 : struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
238 0 : loff_t pos = iocb->ki_pos;
239 0 : bool should_dirty = false;
240 0 : struct bio bio;
241 0 : ssize_t ret;
242 0 : blk_qc_t qc;
243 :
244 0 : if ((pos | iov_iter_alignment(iter)) &
245 0 : (bdev_logical_block_size(bdev) - 1))
246 : return -EINVAL;
247 :
248 0 : if (nr_pages <= DIO_INLINE_BIO_VECS)
249 : vecs = inline_vecs;
250 : else {
251 0 : vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
252 : GFP_KERNEL);
253 0 : if (!vecs)
254 : return -ENOMEM;
255 : }
256 :
257 0 : bio_init(&bio, vecs, nr_pages);
258 0 : bio_set_dev(&bio, bdev);
259 0 : bio.bi_iter.bi_sector = pos >> 9;
260 0 : bio.bi_write_hint = iocb->ki_hint;
261 0 : bio.bi_private = current;
262 0 : bio.bi_end_io = blkdev_bio_end_io_simple;
263 0 : bio.bi_ioprio = iocb->ki_ioprio;
264 :
265 0 : ret = bio_iov_iter_get_pages(&bio, iter);
266 0 : if (unlikely(ret))
267 0 : goto out;
268 0 : ret = bio.bi_iter.bi_size;
269 :
270 0 : if (iov_iter_rw(iter) == READ) {
271 0 : bio.bi_opf = REQ_OP_READ;
272 0 : if (iter_is_iovec(iter))
273 0 : should_dirty = true;
274 : } else {
275 0 : bio.bi_opf = dio_bio_write_op(iocb);
276 0 : task_io_account_write(ret);
277 : }
278 0 : if (iocb->ki_flags & IOCB_HIPRI)
279 0 : bio_set_polled(&bio, iocb);
280 :
281 0 : qc = submit_bio(&bio);
282 0 : for (;;) {
283 0 : set_current_state(TASK_UNINTERRUPTIBLE);
284 0 : if (!READ_ONCE(bio.bi_private))
285 : break;
286 0 : if (!(iocb->ki_flags & IOCB_HIPRI) ||
287 0 : !blk_poll(bdev_get_queue(bdev), qc, true))
288 0 : blk_io_schedule();
289 : }
290 0 : __set_current_state(TASK_RUNNING);
291 :
292 0 : bio_release_pages(&bio, should_dirty);
293 0 : if (unlikely(bio.bi_status))
294 0 : ret = blk_status_to_errno(bio.bi_status);
295 :
296 0 : out:
297 0 : if (vecs != inline_vecs)
298 0 : kfree(vecs);
299 :
300 0 : bio_uninit(&bio);
301 :
302 0 : return ret;
303 : }
304 :
305 : struct blkdev_dio {
306 : union {
307 : struct kiocb *iocb;
308 : struct task_struct *waiter;
309 : };
310 : size_t size;
311 : atomic_t ref;
312 : bool multi_bio : 1;
313 : bool should_dirty : 1;
314 : bool is_sync : 1;
315 : struct bio bio;
316 : };
317 :
318 : static struct bio_set blkdev_dio_pool;
319 :
320 0 : static int blkdev_iopoll(struct kiocb *kiocb, bool wait)
321 : {
322 0 : struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host);
323 0 : struct request_queue *q = bdev_get_queue(bdev);
324 :
325 0 : return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait);
326 : }
327 :
328 0 : static void blkdev_bio_end_io(struct bio *bio)
329 : {
330 0 : struct blkdev_dio *dio = bio->bi_private;
331 0 : bool should_dirty = dio->should_dirty;
332 :
333 0 : if (bio->bi_status && !dio->bio.bi_status)
334 0 : dio->bio.bi_status = bio->bi_status;
335 :
336 0 : if (!dio->multi_bio || atomic_dec_and_test(&dio->ref)) {
337 0 : if (!dio->is_sync) {
338 0 : struct kiocb *iocb = dio->iocb;
339 0 : ssize_t ret;
340 :
341 0 : if (likely(!dio->bio.bi_status)) {
342 0 : ret = dio->size;
343 0 : iocb->ki_pos += ret;
344 : } else {
345 0 : ret = blk_status_to_errno(dio->bio.bi_status);
346 : }
347 :
348 0 : dio->iocb->ki_complete(iocb, ret, 0);
349 0 : if (dio->multi_bio)
350 0 : bio_put(&dio->bio);
351 : } else {
352 0 : struct task_struct *waiter = dio->waiter;
353 :
354 0 : WRITE_ONCE(dio->waiter, NULL);
355 0 : blk_wake_io_task(waiter);
356 : }
357 : }
358 :
359 0 : if (should_dirty) {
360 0 : bio_check_pages_dirty(bio);
361 : } else {
362 0 : bio_release_pages(bio, false);
363 0 : bio_put(bio);
364 : }
365 0 : }
366 :
367 0 : static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
368 : unsigned int nr_pages)
369 : {
370 0 : struct file *file = iocb->ki_filp;
371 0 : struct inode *inode = bdev_file_inode(file);
372 0 : struct block_device *bdev = I_BDEV(inode);
373 0 : struct blk_plug plug;
374 0 : struct blkdev_dio *dio;
375 0 : struct bio *bio;
376 0 : bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
377 0 : bool is_read = (iov_iter_rw(iter) == READ), is_sync;
378 0 : loff_t pos = iocb->ki_pos;
379 0 : blk_qc_t qc = BLK_QC_T_NONE;
380 0 : int ret = 0;
381 :
382 0 : if ((pos | iov_iter_alignment(iter)) &
383 0 : (bdev_logical_block_size(bdev) - 1))
384 : return -EINVAL;
385 :
386 0 : bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);
387 :
388 0 : dio = container_of(bio, struct blkdev_dio, bio);
389 0 : dio->is_sync = is_sync = is_sync_kiocb(iocb);
390 0 : if (dio->is_sync) {
391 0 : dio->waiter = current;
392 0 : bio_get(bio);
393 : } else {
394 0 : dio->iocb = iocb;
395 : }
396 :
397 0 : dio->size = 0;
398 0 : dio->multi_bio = false;
399 0 : dio->should_dirty = is_read && iter_is_iovec(iter);
400 :
401 : /*
402 : * Don't plug for HIPRI/polled IO, as those should go straight
403 : * to issue
404 : */
405 0 : if (!is_poll)
406 0 : blk_start_plug(&plug);
407 :
408 0 : for (;;) {
409 0 : bio_set_dev(bio, bdev);
410 0 : bio->bi_iter.bi_sector = pos >> 9;
411 0 : bio->bi_write_hint = iocb->ki_hint;
412 0 : bio->bi_private = dio;
413 0 : bio->bi_end_io = blkdev_bio_end_io;
414 0 : bio->bi_ioprio = iocb->ki_ioprio;
415 :
416 0 : ret = bio_iov_iter_get_pages(bio, iter);
417 0 : if (unlikely(ret)) {
418 0 : bio->bi_status = BLK_STS_IOERR;
419 0 : bio_endio(bio);
420 0 : break;
421 : }
422 :
423 0 : if (is_read) {
424 0 : bio->bi_opf = REQ_OP_READ;
425 0 : if (dio->should_dirty)
426 0 : bio_set_pages_dirty(bio);
427 : } else {
428 0 : bio->bi_opf = dio_bio_write_op(iocb);
429 0 : task_io_account_write(bio->bi_iter.bi_size);
430 : }
431 :
432 0 : dio->size += bio->bi_iter.bi_size;
433 0 : pos += bio->bi_iter.bi_size;
434 :
435 0 : nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
436 0 : if (!nr_pages) {
437 0 : bool polled = false;
438 :
439 0 : if (iocb->ki_flags & IOCB_HIPRI) {
440 0 : bio_set_polled(bio, iocb);
441 : polled = true;
442 : }
443 :
444 0 : qc = submit_bio(bio);
445 :
446 0 : if (polled)
447 0 : WRITE_ONCE(iocb->ki_cookie, qc);
448 : break;
449 : }
450 :
451 0 : if (!dio->multi_bio) {
452 : /*
453 : * AIO needs an extra reference to ensure the dio
454 : * structure which is embedded into the first bio
455 : * stays around.
456 : */
457 0 : if (!is_sync)
458 0 : bio_get(bio);
459 0 : dio->multi_bio = true;
460 0 : atomic_set(&dio->ref, 2);
461 : } else {
462 0 : atomic_inc(&dio->ref);
463 : }
464 :
465 0 : submit_bio(bio);
466 0 : bio = bio_alloc(GFP_KERNEL, nr_pages);
467 : }
468 :
469 0 : if (!is_poll)
470 0 : blk_finish_plug(&plug);
471 :
472 0 : if (!is_sync)
473 : return -EIOCBQUEUED;
474 :
475 0 : for (;;) {
476 0 : set_current_state(TASK_UNINTERRUPTIBLE);
477 0 : if (!READ_ONCE(dio->waiter))
478 : break;
479 :
480 0 : if (!(iocb->ki_flags & IOCB_HIPRI) ||
481 0 : !blk_poll(bdev_get_queue(bdev), qc, true))
482 0 : blk_io_schedule();
483 : }
484 0 : __set_current_state(TASK_RUNNING);
485 :
486 0 : if (!ret)
487 0 : ret = blk_status_to_errno(dio->bio.bi_status);
488 0 : if (likely(!ret))
489 0 : ret = dio->size;
490 :
491 0 : bio_put(&dio->bio);
492 0 : return ret;
493 : }
494 :
495 : static ssize_t
496 0 : blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
497 : {
498 0 : unsigned int nr_pages;
499 :
500 0 : if (!iov_iter_count(iter))
501 : return 0;
502 :
503 0 : nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
504 0 : if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_VECS)
505 0 : return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
506 :
507 0 : return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
508 : }
509 :
510 1 : static __init int blkdev_init(void)
511 : {
512 1 : return bioset_init(&blkdev_dio_pool, 4, offsetof(struct blkdev_dio, bio), BIOSET_NEED_BVECS);
513 : }
514 : module_init(blkdev_init);
515 :
516 229 : int __sync_blockdev(struct block_device *bdev, int wait)
517 : {
518 229 : if (!bdev)
519 : return 0;
520 27 : if (!wait)
521 0 : return filemap_flush(bdev->bd_inode->i_mapping);
522 27 : return filemap_write_and_wait(bdev->bd_inode->i_mapping);
523 : }
524 :
525 : /*
526 : * Write out and wait upon all the dirty data associated with a block
527 : * device via its mapping. Does not take the superblock lock.
528 : */
529 27 : int sync_blockdev(struct block_device *bdev)
530 : {
531 5 : return __sync_blockdev(bdev, 1);
532 : }
533 : EXPORT_SYMBOL(sync_blockdev);
534 :
535 : /*
536 : * Write out and wait upon all dirty data associated with this
537 : * device. Filesystem data as well as the underlying block
538 : * device. Takes the superblock lock.
539 : */
540 0 : int fsync_bdev(struct block_device *bdev)
541 : {
542 0 : struct super_block *sb = get_super(bdev);
543 0 : if (sb) {
544 0 : int res = sync_filesystem(sb);
545 0 : drop_super(sb);
546 0 : return res;
547 : }
548 0 : return sync_blockdev(bdev);
549 : }
550 : EXPORT_SYMBOL(fsync_bdev);
551 :
552 : /**
553 : * freeze_bdev -- lock a filesystem and force it into a consistent state
554 : * @bdev: blockdevice to lock
555 : *
556 : * If a superblock is found on this device, we take the s_umount semaphore
557 : * on it to make sure nobody unmounts until the snapshot creation is done.
558 : * The reference counter (bd_fsfreeze_count) guarantees that only the last
559 : * unfreeze process can unfreeze the frozen filesystem actually when multiple
560 : * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
561 : * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
562 : * actually.
563 : */
564 0 : int freeze_bdev(struct block_device *bdev)
565 : {
566 0 : struct super_block *sb;
567 0 : int error = 0;
568 :
569 0 : mutex_lock(&bdev->bd_fsfreeze_mutex);
570 0 : if (++bdev->bd_fsfreeze_count > 1)
571 0 : goto done;
572 :
573 0 : sb = get_active_super(bdev);
574 0 : if (!sb)
575 0 : goto sync;
576 0 : if (sb->s_op->freeze_super)
577 0 : error = sb->s_op->freeze_super(sb);
578 : else
579 0 : error = freeze_super(sb);
580 0 : deactivate_super(sb);
581 :
582 0 : if (error) {
583 0 : bdev->bd_fsfreeze_count--;
584 0 : goto done;
585 : }
586 0 : bdev->bd_fsfreeze_sb = sb;
587 :
588 0 : sync:
589 0 : sync_blockdev(bdev);
590 0 : done:
591 0 : mutex_unlock(&bdev->bd_fsfreeze_mutex);
592 0 : return error;
593 : }
594 : EXPORT_SYMBOL(freeze_bdev);
595 :
596 : /**
597 : * thaw_bdev -- unlock filesystem
598 : * @bdev: blockdevice to unlock
599 : *
600 : * Unlocks the filesystem and marks it writeable again after freeze_bdev().
601 : */
602 0 : int thaw_bdev(struct block_device *bdev)
603 : {
604 0 : struct super_block *sb;
605 0 : int error = -EINVAL;
606 :
607 0 : mutex_lock(&bdev->bd_fsfreeze_mutex);
608 0 : if (!bdev->bd_fsfreeze_count)
609 0 : goto out;
610 :
611 0 : error = 0;
612 0 : if (--bdev->bd_fsfreeze_count > 0)
613 0 : goto out;
614 :
615 0 : sb = bdev->bd_fsfreeze_sb;
616 0 : if (!sb)
617 0 : goto out;
618 :
619 0 : if (sb->s_op->thaw_super)
620 0 : error = sb->s_op->thaw_super(sb);
621 : else
622 0 : error = thaw_super(sb);
623 0 : if (error)
624 0 : bdev->bd_fsfreeze_count++;
625 : else
626 0 : bdev->bd_fsfreeze_sb = NULL;
627 0 : out:
628 0 : mutex_unlock(&bdev->bd_fsfreeze_mutex);
629 0 : return error;
630 : }
631 : EXPORT_SYMBOL(thaw_bdev);
632 :
633 872 : static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
634 : {
635 872 : return block_write_full_page(page, blkdev_get_block, wbc);
636 : }
637 :
638 11 : static int blkdev_readpage(struct file * file, struct page * page)
639 : {
640 11 : return block_read_full_page(page, blkdev_get_block);
641 : }
642 :
643 72 : static void blkdev_readahead(struct readahead_control *rac)
644 : {
645 72 : mpage_readahead(rac, blkdev_get_block);
646 72 : }
647 :
648 0 : static int blkdev_write_begin(struct file *file, struct address_space *mapping,
649 : loff_t pos, unsigned len, unsigned flags,
650 : struct page **pagep, void **fsdata)
651 : {
652 0 : return block_write_begin(mapping, pos, len, flags, pagep,
653 : blkdev_get_block);
654 : }
655 :
656 0 : static int blkdev_write_end(struct file *file, struct address_space *mapping,
657 : loff_t pos, unsigned len, unsigned copied,
658 : struct page *page, void *fsdata)
659 : {
660 0 : int ret;
661 0 : ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
662 :
663 0 : unlock_page(page);
664 0 : put_page(page);
665 :
666 0 : return ret;
667 : }
668 :
669 : /*
670 : * private llseek:
671 : * for a block special file file_inode(file)->i_size is zero
672 : * so we compute the size by hand (just as in block_read/write above)
673 : */
674 181 : static loff_t block_llseek(struct file *file, loff_t offset, int whence)
675 : {
676 181 : struct inode *bd_inode = bdev_file_inode(file);
677 181 : loff_t retval;
678 :
679 181 : inode_lock(bd_inode);
680 181 : retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
681 181 : inode_unlock(bd_inode);
682 181 : return retval;
683 : }
684 :
685 1 : int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
686 : {
687 1 : struct inode *bd_inode = bdev_file_inode(filp);
688 1 : struct block_device *bdev = I_BDEV(bd_inode);
689 1 : int error;
690 :
691 1 : error = file_write_and_wait_range(filp, start, end);
692 1 : if (error)
693 : return error;
694 :
695 : /*
696 : * There is no need to serialise calls to blkdev_issue_flush with
697 : * i_mutex and doing so causes performance issues with concurrent
698 : * O_SYNC writers to a block device.
699 : */
700 1 : error = blkdev_issue_flush(bdev);
701 1 : if (error == -EOPNOTSUPP)
702 0 : error = 0;
703 :
704 : return error;
705 : }
706 : EXPORT_SYMBOL(blkdev_fsync);
707 :
708 : /**
709 : * bdev_read_page() - Start reading a page from a block device
710 : * @bdev: The device to read the page from
711 : * @sector: The offset on the device to read the page to (need not be aligned)
712 : * @page: The page to read
713 : *
714 : * On entry, the page should be locked. It will be unlocked when the page
715 : * has been read. If the block driver implements rw_page synchronously,
716 : * that will be true on exit from this function, but it need not be.
717 : *
718 : * Errors returned by this function are usually "soft", eg out of memory, or
719 : * queue full; callers should try a different route to read this page rather
720 : * than propagate an error back up the stack.
721 : *
722 : * Return: negative errno if an error occurs, 0 if submission was successful.
723 : */
724 72 : int bdev_read_page(struct block_device *bdev, sector_t sector,
725 : struct page *page)
726 : {
727 72 : const struct block_device_operations *ops = bdev->bd_disk->fops;
728 72 : int result = -EOPNOTSUPP;
729 :
730 72 : if (!ops->rw_page || bdev_get_integrity(bdev))
731 : return result;
732 :
733 0 : result = blk_queue_enter(bdev->bd_disk->queue, 0);
734 0 : if (result)
735 : return result;
736 0 : result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
737 : REQ_OP_READ);
738 0 : blk_queue_exit(bdev->bd_disk->queue);
739 0 : return result;
740 : }
741 :
742 : /**
743 : * bdev_write_page() - Start writing a page to a block device
744 : * @bdev: The device to write the page to
745 : * @sector: The offset on the device to write the page to (need not be aligned)
746 : * @page: The page to write
747 : * @wbc: The writeback_control for the write
748 : *
749 : * On entry, the page should be locked and not currently under writeback.
750 : * On exit, if the write started successfully, the page will be unlocked and
751 : * under writeback. If the write failed already (eg the driver failed to
752 : * queue the page to the device), the page will still be locked. If the
753 : * caller is a ->writepage implementation, it will need to unlock the page.
754 : *
755 : * Errors returned by this function are usually "soft", eg out of memory, or
756 : * queue full; callers should try a different route to write this page rather
757 : * than propagate an error back up the stack.
758 : *
759 : * Return: negative errno if an error occurs, 0 if submission was successful.
760 : */
761 0 : int bdev_write_page(struct block_device *bdev, sector_t sector,
762 : struct page *page, struct writeback_control *wbc)
763 : {
764 0 : int result;
765 0 : const struct block_device_operations *ops = bdev->bd_disk->fops;
766 :
767 0 : if (!ops->rw_page || bdev_get_integrity(bdev))
768 : return -EOPNOTSUPP;
769 0 : result = blk_queue_enter(bdev->bd_disk->queue, 0);
770 0 : if (result)
771 : return result;
772 :
773 0 : set_page_writeback(page);
774 0 : result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
775 : REQ_OP_WRITE);
776 0 : if (result) {
777 0 : end_page_writeback(page);
778 : } else {
779 0 : clean_page_buffers(page);
780 0 : unlock_page(page);
781 : }
782 0 : blk_queue_exit(bdev->bd_disk->queue);
783 0 : return result;
784 : }
785 :
786 : /*
787 : * pseudo-fs
788 : */
789 :
790 : static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
791 : static struct kmem_cache * bdev_cachep __read_mostly;
792 :
793 11 : static struct inode *bdev_alloc_inode(struct super_block *sb)
794 : {
795 11 : struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
796 :
797 11 : if (!ei)
798 : return NULL;
799 11 : memset(&ei->bdev, 0, sizeof(ei->bdev));
800 11 : ei->bdev.bd_bdi = &noop_backing_dev_info;
801 11 : return &ei->vfs_inode;
802 : }
803 :
804 0 : static void bdev_free_inode(struct inode *inode)
805 : {
806 0 : struct block_device *bdev = I_BDEV(inode);
807 :
808 0 : free_percpu(bdev->bd_stats);
809 0 : kfree(bdev->bd_meta_info);
810 :
811 0 : kmem_cache_free(bdev_cachep, BDEV_I(inode));
812 0 : }
813 :
814 26 : static void init_once(void *data)
815 : {
816 26 : struct bdev_inode *ei = data;
817 :
818 26 : inode_init_once(&ei->vfs_inode);
819 26 : }
820 :
821 0 : static void bdev_evict_inode(struct inode *inode)
822 : {
823 0 : struct block_device *bdev = &BDEV_I(inode)->bdev;
824 0 : truncate_inode_pages_final(&inode->i_data);
825 0 : invalidate_inode_buffers(inode); /* is it needed here? */
826 0 : clear_inode(inode);
827 : /* Detach inode from wb early as bdi_put() may free bdi->wb */
828 0 : inode_detach_wb(inode);
829 0 : if (bdev->bd_bdi != &noop_backing_dev_info) {
830 0 : bdi_put(bdev->bd_bdi);
831 0 : bdev->bd_bdi = &noop_backing_dev_info;
832 : }
833 0 : }
834 :
835 : static const struct super_operations bdev_sops = {
836 : .statfs = simple_statfs,
837 : .alloc_inode = bdev_alloc_inode,
838 : .free_inode = bdev_free_inode,
839 : .drop_inode = generic_delete_inode,
840 : .evict_inode = bdev_evict_inode,
841 : };
842 :
843 1 : static int bd_init_fs_context(struct fs_context *fc)
844 : {
845 1 : struct pseudo_fs_context *ctx = init_pseudo(fc, BDEVFS_MAGIC);
846 1 : if (!ctx)
847 : return -ENOMEM;
848 1 : fc->s_iflags |= SB_I_CGROUPWB;
849 1 : ctx->ops = &bdev_sops;
850 1 : return 0;
851 : }
852 :
853 : static struct file_system_type bd_type = {
854 : .name = "bdev",
855 : .init_fs_context = bd_init_fs_context,
856 : .kill_sb = kill_anon_super,
857 : };
858 :
859 : struct super_block *blockdev_superblock __read_mostly;
860 : EXPORT_SYMBOL_GPL(blockdev_superblock);
861 :
862 1 : void __init bdev_cache_init(void)
863 : {
864 1 : int err;
865 1 : static struct vfsmount *bd_mnt;
866 :
867 1 : bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
868 : 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
869 : SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC),
870 : init_once);
871 1 : err = register_filesystem(&bd_type);
872 1 : if (err)
873 0 : panic("Cannot register bdev pseudo-fs");
874 1 : bd_mnt = kern_mount(&bd_type);
875 1 : if (IS_ERR(bd_mnt))
876 0 : panic("Cannot create bdev pseudo-fs");
877 1 : blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
878 1 : }
879 :
880 10 : struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
881 : {
882 10 : struct block_device *bdev;
883 10 : struct inode *inode;
884 :
885 10 : inode = new_inode(blockdev_superblock);
886 10 : if (!inode)
887 : return NULL;
888 10 : inode->i_mode = S_IFBLK;
889 10 : inode->i_rdev = 0;
890 10 : inode->i_data.a_ops = &def_blk_aops;
891 10 : mapping_set_gfp_mask(&inode->i_data, GFP_USER);
892 :
893 10 : bdev = I_BDEV(inode);
894 10 : mutex_init(&bdev->bd_mutex);
895 10 : mutex_init(&bdev->bd_fsfreeze_mutex);
896 10 : spin_lock_init(&bdev->bd_size_lock);
897 10 : bdev->bd_disk = disk;
898 10 : bdev->bd_partno = partno;
899 10 : bdev->bd_inode = inode;
900 : #ifdef CONFIG_SYSFS
901 10 : INIT_LIST_HEAD(&bdev->bd_holder_disks);
902 : #endif
903 10 : bdev->bd_stats = alloc_percpu(struct disk_stats);
904 10 : if (!bdev->bd_stats) {
905 0 : iput(inode);
906 0 : return NULL;
907 : }
908 : return bdev;
909 : }
910 :
911 10 : void bdev_add(struct block_device *bdev, dev_t dev)
912 : {
913 10 : bdev->bd_dev = dev;
914 10 : bdev->bd_inode->i_rdev = dev;
915 10 : bdev->bd_inode->i_ino = dev;
916 10 : insert_inode_hash(bdev->bd_inode);
917 10 : }
918 :
919 32 : static struct block_device *bdget(dev_t dev)
920 : {
921 32 : struct inode *inode;
922 :
923 32 : inode = ilookup(blockdev_superblock, dev);
924 32 : if (!inode)
925 : return NULL;
926 32 : return &BDEV_I(inode)->bdev;
927 : }
928 :
929 : /**
930 : * bdgrab -- Grab a reference to an already referenced block device
931 : * @bdev: Block device to grab a reference to.
932 : *
933 : * Returns the block_device with an additional reference when successful,
934 : * or NULL if the inode is already beeing freed.
935 : */
936 14 : struct block_device *bdgrab(struct block_device *bdev)
937 : {
938 14 : if (!igrab(bdev->bd_inode))
939 0 : return NULL;
940 : return bdev;
941 : }
942 : EXPORT_SYMBOL(bdgrab);
943 :
944 14 : long nr_blockdev_pages(void)
945 : {
946 14 : struct inode *inode;
947 14 : long ret = 0;
948 :
949 14 : spin_lock(&blockdev_superblock->s_inode_list_lock);
950 148 : list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list)
951 134 : ret += inode->i_mapping->nrpages;
952 14 : spin_unlock(&blockdev_superblock->s_inode_list_lock);
953 :
954 14 : return ret;
955 : }
956 :
957 44 : void bdput(struct block_device *bdev)
958 : {
959 12 : iput(bdev->bd_inode);
960 1 : }
961 : EXPORT_SYMBOL(bdput);
962 :
963 : /**
964 : * bd_may_claim - test whether a block device can be claimed
965 : * @bdev: block device of interest
966 : * @whole: whole block device containing @bdev, may equal @bdev
967 : * @holder: holder trying to claim @bdev
968 : *
969 : * Test whether @bdev can be claimed by @holder.
970 : *
971 : * CONTEXT:
972 : * spin_lock(&bdev_lock).
973 : *
974 : * RETURNS:
975 : * %true if @bdev can be claimed, %false otherwise.
976 : */
977 5 : static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
978 : void *holder)
979 : {
980 0 : if (bdev->bd_holder == holder)
981 : return true; /* already a holder */
982 5 : else if (bdev->bd_holder != NULL)
983 : return false; /* held by someone else */
984 4 : else if (whole == bdev)
985 : return true; /* is a whole device which isn't held */
986 :
987 4 : else if (whole->bd_holder == bd_may_claim)
988 : return true; /* is a partition of a device that is being partitioned */
989 4 : else if (whole->bd_holder != NULL)
990 : return false; /* is a partition of a held device */
991 : else
992 2 : return true; /* is a partition of an un-held device */
993 : }
994 :
995 : /**
996 : * bd_prepare_to_claim - claim a block device
997 : * @bdev: block device of interest
998 : * @holder: holder trying to claim @bdev
999 : *
1000 : * Claim @bdev. This function fails if @bdev is already claimed by another
1001 : * holder and waits if another claiming is in progress. return, the caller
1002 : * has ownership of bd_claiming and bd_holder[s].
1003 : *
1004 : * RETURNS:
1005 : * 0 if @bdev can be claimed, -EBUSY otherwise.
1006 : */
1007 3 : int bd_prepare_to_claim(struct block_device *bdev, void *holder)
1008 : {
1009 3 : struct block_device *whole = bdev_whole(bdev);
1010 :
1011 3 : if (WARN_ON_ONCE(!holder))
1012 : return -EINVAL;
1013 3 : retry:
1014 3 : spin_lock(&bdev_lock);
1015 : /* if someone else claimed, fail */
1016 3 : if (!bd_may_claim(bdev, whole, holder)) {
1017 1 : spin_unlock(&bdev_lock);
1018 1 : return -EBUSY;
1019 : }
1020 :
1021 : /* if claiming is already in progress, wait for it to finish */
1022 2 : if (whole->bd_claiming) {
1023 0 : wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
1024 0 : DEFINE_WAIT(wait);
1025 :
1026 0 : prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
1027 0 : spin_unlock(&bdev_lock);
1028 0 : schedule();
1029 0 : finish_wait(wq, &wait);
1030 0 : goto retry;
1031 : }
1032 :
1033 : /* yay, all mine */
1034 2 : whole->bd_claiming = holder;
1035 2 : spin_unlock(&bdev_lock);
1036 2 : return 0;
1037 : }
1038 : EXPORT_SYMBOL_GPL(bd_prepare_to_claim); /* only for the loop driver */
1039 :
1040 2 : static void bd_clear_claiming(struct block_device *whole, void *holder)
1041 : {
1042 6 : lockdep_assert_held(&bdev_lock);
1043 : /* tell others that we're done */
1044 2 : BUG_ON(whole->bd_claiming != holder);
1045 2 : whole->bd_claiming = NULL;
1046 2 : wake_up_bit(&whole->bd_claiming, 0);
1047 2 : }
1048 :
1049 : /**
1050 : * bd_finish_claiming - finish claiming of a block device
1051 : * @bdev: block device of interest
1052 : * @holder: holder that has claimed @bdev
1053 : *
1054 : * Finish exclusive open of a block device. Mark the device as exlusively
1055 : * open by the holder and wake up all waiters for exclusive open to finish.
1056 : */
1057 2 : static void bd_finish_claiming(struct block_device *bdev, void *holder)
1058 : {
1059 2 : struct block_device *whole = bdev_whole(bdev);
1060 :
1061 2 : spin_lock(&bdev_lock);
1062 4 : BUG_ON(!bd_may_claim(bdev, whole, holder));
1063 : /*
1064 : * Note that for a whole device bd_holders will be incremented twice,
1065 : * and bd_holder will be set to bd_may_claim before being set to holder
1066 : */
1067 2 : whole->bd_holders++;
1068 2 : whole->bd_holder = bd_may_claim;
1069 2 : bdev->bd_holders++;
1070 2 : bdev->bd_holder = holder;
1071 2 : bd_clear_claiming(whole, holder);
1072 2 : spin_unlock(&bdev_lock);
1073 2 : }
1074 :
1075 : /**
1076 : * bd_abort_claiming - abort claiming of a block device
1077 : * @bdev: block device of interest
1078 : * @holder: holder that has claimed @bdev
1079 : *
1080 : * Abort claiming of a block device when the exclusive open failed. This can be
1081 : * also used when exclusive open is not actually desired and we just needed
1082 : * to block other exclusive openers for a while.
1083 : */
1084 0 : void bd_abort_claiming(struct block_device *bdev, void *holder)
1085 : {
1086 0 : spin_lock(&bdev_lock);
1087 0 : bd_clear_claiming(bdev_whole(bdev), holder);
1088 0 : spin_unlock(&bdev_lock);
1089 0 : }
1090 : EXPORT_SYMBOL(bd_abort_claiming);
1091 :
1092 : #ifdef CONFIG_SYSFS
1093 : struct bd_holder_disk {
1094 : struct list_head list;
1095 : struct gendisk *disk;
1096 : int refcnt;
1097 : };
1098 :
1099 0 : static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
1100 : struct gendisk *disk)
1101 : {
1102 0 : struct bd_holder_disk *holder;
1103 :
1104 0 : list_for_each_entry(holder, &bdev->bd_holder_disks, list)
1105 0 : if (holder->disk == disk)
1106 : return holder;
1107 : return NULL;
1108 : }
1109 :
1110 0 : static int add_symlink(struct kobject *from, struct kobject *to)
1111 : {
1112 0 : return sysfs_create_link(from, to, kobject_name(to));
1113 : }
1114 :
1115 0 : static void del_symlink(struct kobject *from, struct kobject *to)
1116 : {
1117 0 : sysfs_remove_link(from, kobject_name(to));
1118 0 : }
1119 :
1120 : /**
1121 : * bd_link_disk_holder - create symlinks between holding disk and slave bdev
1122 : * @bdev: the claimed slave bdev
1123 : * @disk: the holding disk
1124 : *
1125 : * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1126 : *
1127 : * This functions creates the following sysfs symlinks.
1128 : *
1129 : * - from "slaves" directory of the holder @disk to the claimed @bdev
1130 : * - from "holders" directory of the @bdev to the holder @disk
1131 : *
1132 : * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
1133 : * passed to bd_link_disk_holder(), then:
1134 : *
1135 : * /sys/block/dm-0/slaves/sda --> /sys/block/sda
1136 : * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
1137 : *
1138 : * The caller must have claimed @bdev before calling this function and
1139 : * ensure that both @bdev and @disk are valid during the creation and
1140 : * lifetime of these symlinks.
1141 : *
1142 : * CONTEXT:
1143 : * Might sleep.
1144 : *
1145 : * RETURNS:
1146 : * 0 on success, -errno on failure.
1147 : */
1148 0 : int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
1149 : {
1150 0 : struct bd_holder_disk *holder;
1151 0 : int ret = 0;
1152 :
1153 0 : mutex_lock(&bdev->bd_mutex);
1154 :
1155 0 : WARN_ON_ONCE(!bdev->bd_holder);
1156 :
1157 : /* FIXME: remove the following once add_disk() handles errors */
1158 0 : if (WARN_ON(!disk->slave_dir || !bdev->bd_holder_dir))
1159 0 : goto out_unlock;
1160 :
1161 0 : holder = bd_find_holder_disk(bdev, disk);
1162 0 : if (holder) {
1163 0 : holder->refcnt++;
1164 0 : goto out_unlock;
1165 : }
1166 :
1167 0 : holder = kzalloc(sizeof(*holder), GFP_KERNEL);
1168 0 : if (!holder) {
1169 0 : ret = -ENOMEM;
1170 0 : goto out_unlock;
1171 : }
1172 :
1173 0 : INIT_LIST_HEAD(&holder->list);
1174 0 : holder->disk = disk;
1175 0 : holder->refcnt = 1;
1176 :
1177 0 : ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));
1178 0 : if (ret)
1179 0 : goto out_free;
1180 :
1181 0 : ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
1182 0 : if (ret)
1183 0 : goto out_del;
1184 : /*
1185 : * bdev could be deleted beneath us which would implicitly destroy
1186 : * the holder directory. Hold on to it.
1187 : */
1188 0 : kobject_get(bdev->bd_holder_dir);
1189 :
1190 0 : list_add(&holder->list, &bdev->bd_holder_disks);
1191 0 : goto out_unlock;
1192 :
1193 0 : out_del:
1194 0 : del_symlink(disk->slave_dir, bdev_kobj(bdev));
1195 0 : out_free:
1196 0 : kfree(holder);
1197 0 : out_unlock:
1198 0 : mutex_unlock(&bdev->bd_mutex);
1199 0 : return ret;
1200 : }
1201 : EXPORT_SYMBOL_GPL(bd_link_disk_holder);
1202 :
1203 : /**
1204 : * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
1205 : * @bdev: the calimed slave bdev
1206 : * @disk: the holding disk
1207 : *
1208 : * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1209 : *
1210 : * CONTEXT:
1211 : * Might sleep.
1212 : */
1213 0 : void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
1214 : {
1215 0 : struct bd_holder_disk *holder;
1216 :
1217 0 : mutex_lock(&bdev->bd_mutex);
1218 :
1219 0 : holder = bd_find_holder_disk(bdev, disk);
1220 :
1221 0 : if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
1222 0 : del_symlink(disk->slave_dir, bdev_kobj(bdev));
1223 0 : del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
1224 0 : kobject_put(bdev->bd_holder_dir);
1225 0 : list_del_init(&holder->list);
1226 0 : kfree(holder);
1227 : }
1228 :
1229 0 : mutex_unlock(&bdev->bd_mutex);
1230 0 : }
1231 : EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
1232 : #endif
1233 :
1234 : static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
1235 :
1236 1 : int bdev_disk_changed(struct block_device *bdev, bool invalidate)
1237 : {
1238 1 : struct gendisk *disk = bdev->bd_disk;
1239 1 : int ret;
1240 :
1241 2 : lockdep_assert_held(&bdev->bd_mutex);
1242 :
1243 1 : clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1244 :
1245 1 : rescan:
1246 1 : ret = blk_drop_partitions(bdev);
1247 1 : if (ret)
1248 0 : return ret;
1249 :
1250 : /*
1251 : * Historically we only set the capacity to zero for devices that
1252 : * support partitions (independ of actually having partitions created).
1253 : * Doing that is rather inconsistent, but changing it broke legacy
1254 : * udisks polling for legacy ide-cdrom devices. Use the crude check
1255 : * below to get the sane behavior for most device while not breaking
1256 : * userspace for this particular setup.
1257 : */
1258 1 : if (invalidate) {
1259 0 : if (disk_part_scan_enabled(disk) ||
1260 0 : !(disk->flags & GENHD_FL_REMOVABLE))
1261 0 : set_capacity(disk, 0);
1262 : } else {
1263 1 : if (disk->fops->revalidate_disk)
1264 0 : disk->fops->revalidate_disk(disk);
1265 : }
1266 :
1267 1 : if (get_capacity(disk)) {
1268 1 : ret = blk_add_partitions(disk, bdev);
1269 1 : if (ret == -EAGAIN)
1270 0 : goto rescan;
1271 0 : } else if (invalidate) {
1272 : /*
1273 : * Tell userspace that the media / partition table may have
1274 : * changed.
1275 : */
1276 0 : kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
1277 : }
1278 :
1279 : return ret;
1280 : }
1281 : /*
1282 : * Only exported for loop and dasd for historic reasons. Don't use in new
1283 : * code!
1284 : */
1285 : EXPORT_SYMBOL_GPL(bdev_disk_changed);
1286 :
1287 : /*
1288 : * bd_mutex locking:
1289 : *
1290 : * mutex_lock(part->bd_mutex)
1291 : * mutex_lock_nested(whole->bd_mutex, 1)
1292 : */
1293 33 : static int __blkdev_get(struct block_device *bdev, fmode_t mode)
1294 : {
1295 33 : struct gendisk *disk = bdev->bd_disk;
1296 33 : int ret = 0;
1297 :
1298 33 : if (!bdev->bd_openers) {
1299 13 : if (!bdev_is_partition(bdev)) {
1300 11 : ret = 0;
1301 11 : if (disk->fops->open)
1302 11 : ret = disk->fops->open(bdev, mode);
1303 :
1304 11 : if (!ret)
1305 11 : set_init_blocksize(bdev);
1306 :
1307 : /*
1308 : * If the device is invalidated, rescan partition
1309 : * if open succeeded or failed with -ENOMEDIUM.
1310 : * The latter is necessary to prevent ghost
1311 : * partitions on a removed medium.
1312 : */
1313 11 : if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
1314 1 : (!ret || ret == -ENOMEDIUM))
1315 1 : bdev_disk_changed(bdev, ret == -ENOMEDIUM);
1316 :
1317 11 : if (ret)
1318 : return ret;
1319 : } else {
1320 2 : struct block_device *whole = bdgrab(disk->part0);
1321 :
1322 2 : mutex_lock_nested(&whole->bd_mutex, 1);
1323 2 : ret = __blkdev_get(whole, mode);
1324 2 : if (ret) {
1325 0 : mutex_unlock(&whole->bd_mutex);
1326 0 : bdput(whole);
1327 0 : return ret;
1328 : }
1329 2 : whole->bd_part_count++;
1330 2 : mutex_unlock(&whole->bd_mutex);
1331 :
1332 2 : if (!(disk->flags & GENHD_FL_UP) ||
1333 2 : !bdev_nr_sectors(bdev)) {
1334 0 : __blkdev_put(whole, mode, 1);
1335 0 : bdput(whole);
1336 0 : return -ENXIO;
1337 : }
1338 2 : set_init_blocksize(bdev);
1339 : }
1340 :
1341 13 : if (bdev->bd_bdi == &noop_backing_dev_info)
1342 10 : bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
1343 : } else {
1344 20 : if (!bdev_is_partition(bdev)) {
1345 15 : if (bdev->bd_disk->fops->open)
1346 15 : ret = bdev->bd_disk->fops->open(bdev, mode);
1347 : /* the same as first opener case, read comment there */
1348 15 : if (test_bit(GD_NEED_PART_SCAN, &disk->state) &&
1349 0 : (!ret || ret == -ENOMEDIUM))
1350 0 : bdev_disk_changed(bdev, ret == -ENOMEDIUM);
1351 15 : if (ret)
1352 : return ret;
1353 : }
1354 : }
1355 33 : bdev->bd_openers++;
1356 33 : return 0;
1357 : }
1358 :
1359 32 : struct block_device *blkdev_get_no_open(dev_t dev)
1360 : {
1361 32 : struct block_device *bdev;
1362 32 : struct gendisk *disk;
1363 :
1364 32 : down_read(&bdev_lookup_sem);
1365 32 : bdev = bdget(dev);
1366 32 : if (!bdev) {
1367 0 : up_read(&bdev_lookup_sem);
1368 0 : blk_request_module(dev);
1369 0 : down_read(&bdev_lookup_sem);
1370 :
1371 0 : bdev = bdget(dev);
1372 0 : if (!bdev)
1373 0 : goto unlock;
1374 : }
1375 :
1376 32 : disk = bdev->bd_disk;
1377 32 : if (!kobject_get_unless_zero(&disk_to_dev(disk)->kobj))
1378 0 : goto bdput;
1379 32 : if ((disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
1380 0 : goto put_disk;
1381 32 : if (!try_module_get(bdev->bd_disk->fops->owner))
1382 : goto put_disk;
1383 32 : up_read(&bdev_lookup_sem);
1384 32 : return bdev;
1385 0 : put_disk:
1386 0 : put_disk(disk);
1387 0 : bdput:
1388 0 : bdput(bdev);
1389 0 : unlock:
1390 0 : up_read(&bdev_lookup_sem);
1391 0 : return NULL;
1392 : }
1393 :
1394 31 : void blkdev_put_no_open(struct block_device *bdev)
1395 : {
1396 31 : module_put(bdev->bd_disk->fops->owner);
1397 31 : put_disk(bdev->bd_disk);
1398 31 : bdput(bdev);
1399 31 : }
1400 :
1401 : /**
1402 : * blkdev_get_by_dev - open a block device by device number
1403 : * @dev: device number of block device to open
1404 : * @mode: FMODE_* mask
1405 : * @holder: exclusive holder identifier
1406 : *
1407 : * Open the block device described by device number @dev. If @mode includes
1408 : * %FMODE_EXCL, the block device is opened with exclusive access. Specifying
1409 : * %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may nest for
1410 : * the same @holder.
1411 : *
1412 : * Use this interface ONLY if you really do not have anything better - i.e. when
1413 : * you are behind a truly sucky interface and all you are given is a device
1414 : * number. Everything else should use blkdev_get_by_path().
1415 : *
1416 : * CONTEXT:
1417 : * Might sleep.
1418 : *
1419 : * RETURNS:
1420 : * Reference to the block_device on success, ERR_PTR(-errno) on failure.
1421 : */
1422 32 : struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
1423 : {
1424 32 : bool unblock_events = true;
1425 32 : struct block_device *bdev;
1426 32 : struct gendisk *disk;
1427 32 : int ret;
1428 :
1429 32 : ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
1430 32 : MAJOR(dev), MINOR(dev),
1431 32 : ((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
1432 : ((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
1433 32 : if (ret)
1434 : return ERR_PTR(ret);
1435 :
1436 : /*
1437 : * If we lost a race with 'disk' being deleted, try again. See md.c.
1438 : */
1439 32 : retry:
1440 32 : bdev = blkdev_get_no_open(dev);
1441 32 : if (!bdev)
1442 32 : return ERR_PTR(-ENXIO);
1443 32 : disk = bdev->bd_disk;
1444 :
1445 32 : if (mode & FMODE_EXCL) {
1446 3 : ret = bd_prepare_to_claim(bdev, holder);
1447 3 : if (ret)
1448 1 : goto put_blkdev;
1449 : }
1450 :
1451 31 : disk_block_events(disk);
1452 :
1453 31 : mutex_lock(&bdev->bd_mutex);
1454 31 : ret =__blkdev_get(bdev, mode);
1455 31 : if (ret)
1456 0 : goto abort_claiming;
1457 31 : if (mode & FMODE_EXCL) {
1458 2 : bd_finish_claiming(bdev, holder);
1459 :
1460 : /*
1461 : * Block event polling for write claims if requested. Any write
1462 : * holder makes the write_holder state stick until all are
1463 : * released. This is good enough and tracking individual
1464 : * writeable reference is too fragile given the way @mode is
1465 : * used in blkdev_get/put().
1466 : */
1467 2 : if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
1468 0 : (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
1469 0 : bdev->bd_write_holder = true;
1470 0 : unblock_events = false;
1471 : }
1472 : }
1473 31 : mutex_unlock(&bdev->bd_mutex);
1474 :
1475 31 : if (unblock_events)
1476 31 : disk_unblock_events(disk);
1477 : return bdev;
1478 :
1479 0 : abort_claiming:
1480 0 : if (mode & FMODE_EXCL)
1481 0 : bd_abort_claiming(bdev, holder);
1482 0 : mutex_unlock(&bdev->bd_mutex);
1483 0 : disk_unblock_events(disk);
1484 1 : put_blkdev:
1485 1 : blkdev_put_no_open(bdev);
1486 1 : if (ret == -ERESTARTSYS)
1487 0 : goto retry;
1488 1 : return ERR_PTR(ret);
1489 : }
1490 : EXPORT_SYMBOL(blkdev_get_by_dev);
1491 :
1492 : /**
1493 : * blkdev_get_by_path - open a block device by name
1494 : * @path: path to the block device to open
1495 : * @mode: FMODE_* mask
1496 : * @holder: exclusive holder identifier
1497 : *
1498 : * Open the block device described by the device file at @path. If @mode
1499 : * includes %FMODE_EXCL, the block device is opened with exclusive access.
1500 : * Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may
1501 : * nest for the same @holder.
1502 : *
1503 : * CONTEXT:
1504 : * Might sleep.
1505 : *
1506 : * RETURNS:
1507 : * Reference to the block_device on success, ERR_PTR(-errno) on failure.
1508 : */
1509 2 : struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
1510 : void *holder)
1511 : {
1512 2 : struct block_device *bdev;
1513 2 : dev_t dev;
1514 2 : int error;
1515 :
1516 2 : error = lookup_bdev(path, &dev);
1517 2 : if (error)
1518 0 : return ERR_PTR(error);
1519 :
1520 2 : bdev = blkdev_get_by_dev(dev, mode, holder);
1521 2 : if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
1522 0 : blkdev_put(bdev, mode);
1523 0 : return ERR_PTR(-EACCES);
1524 : }
1525 :
1526 : return bdev;
1527 : }
1528 : EXPORT_SYMBOL(blkdev_get_by_path);
1529 :
1530 29 : static int blkdev_open(struct inode * inode, struct file * filp)
1531 : {
1532 29 : struct block_device *bdev;
1533 :
1534 : /*
1535 : * Preserve backwards compatibility and allow large file access
1536 : * even if userspace doesn't ask for it explicitly. Some mkfs
1537 : * binary needs it. We might want to drop this workaround
1538 : * during an unstable branch.
1539 : */
1540 29 : filp->f_flags |= O_LARGEFILE;
1541 :
1542 29 : filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
1543 :
1544 29 : if (filp->f_flags & O_NDELAY)
1545 10 : filp->f_mode |= FMODE_NDELAY;
1546 29 : if (filp->f_flags & O_EXCL)
1547 1 : filp->f_mode |= FMODE_EXCL;
1548 29 : if ((filp->f_flags & O_ACCMODE) == 3)
1549 0 : filp->f_mode |= FMODE_WRITE_IOCTL;
1550 :
1551 29 : bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
1552 29 : if (IS_ERR(bdev))
1553 1 : return PTR_ERR(bdev);
1554 28 : filp->f_mapping = bdev->bd_inode->i_mapping;
1555 28 : filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
1556 28 : return 0;
1557 : }
1558 :
1559 31 : static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
1560 : {
1561 31 : struct gendisk *disk = bdev->bd_disk;
1562 31 : struct block_device *victim = NULL;
1563 :
1564 : /*
1565 : * Sync early if it looks like we're the last one. If someone else
1566 : * opens the block device between now and the decrement of bd_openers
1567 : * then we did a sync that we didn't need to, but that's not the end
1568 : * of the world and we want to avoid long (could be several minute)
1569 : * syncs while holding the mutex.
1570 : */
1571 31 : if (bdev->bd_openers == 1)
1572 11 : sync_blockdev(bdev);
1573 :
1574 31 : mutex_lock_nested(&bdev->bd_mutex, for_part);
1575 31 : if (for_part)
1576 1 : bdev->bd_part_count--;
1577 :
1578 31 : if (!--bdev->bd_openers) {
1579 11 : WARN_ON_ONCE(bdev->bd_holders);
1580 11 : sync_blockdev(bdev);
1581 11 : kill_bdev(bdev);
1582 11 : bdev_write_inode(bdev);
1583 11 : if (bdev_is_partition(bdev))
1584 1 : victim = bdev_whole(bdev);
1585 : }
1586 :
1587 31 : if (!bdev_is_partition(bdev) && disk->fops->release)
1588 25 : disk->fops->release(disk, mode);
1589 31 : mutex_unlock(&bdev->bd_mutex);
1590 31 : if (victim) {
1591 1 : __blkdev_put(victim, mode, 1);
1592 1 : bdput(victim);
1593 : }
1594 31 : }
1595 :
1596 30 : void blkdev_put(struct block_device *bdev, fmode_t mode)
1597 : {
1598 30 : struct gendisk *disk = bdev->bd_disk;
1599 :
1600 30 : mutex_lock(&bdev->bd_mutex);
1601 :
1602 30 : if (mode & FMODE_EXCL) {
1603 1 : struct block_device *whole = bdev_whole(bdev);
1604 1 : bool bdev_free;
1605 :
1606 : /*
1607 : * Release a claim on the device. The holder fields
1608 : * are protected with bdev_lock. bd_mutex is to
1609 : * synchronize disk_holder unlinking.
1610 : */
1611 1 : spin_lock(&bdev_lock);
1612 :
1613 1 : WARN_ON_ONCE(--bdev->bd_holders < 0);
1614 1 : WARN_ON_ONCE(--whole->bd_holders < 0);
1615 :
1616 1 : if ((bdev_free = !bdev->bd_holders))
1617 1 : bdev->bd_holder = NULL;
1618 1 : if (!whole->bd_holders)
1619 1 : whole->bd_holder = NULL;
1620 :
1621 1 : spin_unlock(&bdev_lock);
1622 :
1623 : /*
1624 : * If this was the last claim, remove holder link and
1625 : * unblock evpoll if it was a write holder.
1626 : */
1627 1 : if (bdev_free && bdev->bd_write_holder) {
1628 0 : disk_unblock_events(disk);
1629 0 : bdev->bd_write_holder = false;
1630 : }
1631 : }
1632 :
1633 : /*
1634 : * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1635 : * event. This is to ensure detection of media removal commanded
1636 : * from userland - e.g. eject(1).
1637 : */
1638 30 : disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE);
1639 30 : mutex_unlock(&bdev->bd_mutex);
1640 :
1641 30 : __blkdev_put(bdev, mode, 0);
1642 30 : blkdev_put_no_open(bdev);
1643 30 : }
1644 : EXPORT_SYMBOL(blkdev_put);
1645 :
1646 28 : static int blkdev_close(struct inode * inode, struct file * filp)
1647 : {
1648 28 : struct block_device *bdev = I_BDEV(bdev_file_inode(filp));
1649 28 : blkdev_put(bdev, filp->f_mode);
1650 28 : return 0;
1651 : }
1652 :
1653 32 : static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
1654 : {
1655 32 : struct block_device *bdev = I_BDEV(bdev_file_inode(file));
1656 32 : fmode_t mode = file->f_mode;
1657 :
1658 : /*
1659 : * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1660 : * to updated it before every ioctl.
1661 : */
1662 32 : if (file->f_flags & O_NDELAY)
1663 0 : mode |= FMODE_NDELAY;
1664 : else
1665 32 : mode &= ~FMODE_NDELAY;
1666 :
1667 32 : return blkdev_ioctl(bdev, mode, cmd, arg);
1668 : }
1669 :
1670 : /*
1671 : * Write data to the block device. Only intended for the block device itself
1672 : * and the raw driver which basically is a fake block device.
1673 : *
1674 : * Does not take i_mutex for the write and thus is not for general purpose
1675 : * use.
1676 : */
1677 0 : ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
1678 : {
1679 0 : struct file *file = iocb->ki_filp;
1680 0 : struct inode *bd_inode = bdev_file_inode(file);
1681 0 : loff_t size = i_size_read(bd_inode);
1682 0 : struct blk_plug plug;
1683 0 : ssize_t ret;
1684 :
1685 0 : if (bdev_read_only(I_BDEV(bd_inode)))
1686 : return -EPERM;
1687 :
1688 0 : if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
1689 : return -ETXTBSY;
1690 :
1691 0 : if (!iov_iter_count(from))
1692 : return 0;
1693 :
1694 0 : if (iocb->ki_pos >= size)
1695 : return -ENOSPC;
1696 :
1697 0 : if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
1698 : return -EOPNOTSUPP;
1699 :
1700 0 : iov_iter_truncate(from, size - iocb->ki_pos);
1701 :
1702 0 : blk_start_plug(&plug);
1703 0 : ret = __generic_file_write_iter(iocb, from);
1704 0 : if (ret > 0)
1705 0 : ret = generic_write_sync(iocb, ret);
1706 0 : blk_finish_plug(&plug);
1707 0 : return ret;
1708 : }
1709 : EXPORT_SYMBOL_GPL(blkdev_write_iter);
1710 :
1711 185 : ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
1712 : {
1713 185 : struct file *file = iocb->ki_filp;
1714 185 : struct inode *bd_inode = bdev_file_inode(file);
1715 185 : loff_t size = i_size_read(bd_inode);
1716 185 : loff_t pos = iocb->ki_pos;
1717 :
1718 185 : if (pos >= size)
1719 : return 0;
1720 :
1721 185 : size -= pos;
1722 185 : iov_iter_truncate(to, size);
1723 185 : return generic_file_read_iter(iocb, to);
1724 : }
1725 : EXPORT_SYMBOL_GPL(blkdev_read_iter);
1726 :
1727 : /*
1728 : * Try to release a page associated with block device when the system
1729 : * is under memory pressure.
1730 : */
1731 3 : static int blkdev_releasepage(struct page *page, gfp_t wait)
1732 : {
1733 3 : struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
1734 :
1735 3 : if (super && super->s_op->bdev_try_to_free_page)
1736 0 : return super->s_op->bdev_try_to_free_page(super, page, wait);
1737 :
1738 3 : return try_to_free_buffers(page);
1739 : }
1740 :
1741 1 : static int blkdev_writepages(struct address_space *mapping,
1742 : struct writeback_control *wbc)
1743 : {
1744 1 : return generic_writepages(mapping, wbc);
1745 : }
1746 :
1747 : static const struct address_space_operations def_blk_aops = {
1748 : .readpage = blkdev_readpage,
1749 : .readahead = blkdev_readahead,
1750 : .writepage = blkdev_writepage,
1751 : .write_begin = blkdev_write_begin,
1752 : .write_end = blkdev_write_end,
1753 : .writepages = blkdev_writepages,
1754 : .releasepage = blkdev_releasepage,
1755 : .direct_IO = blkdev_direct_IO,
1756 : .migratepage = buffer_migrate_page_norefs,
1757 : .is_dirty_writeback = buffer_check_dirty_writeback,
1758 : };
1759 :
1760 : #define BLKDEV_FALLOC_FL_SUPPORTED \
1761 : (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
1762 : FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
1763 :
1764 0 : static long blkdev_fallocate(struct file *file, int mode, loff_t start,
1765 : loff_t len)
1766 : {
1767 0 : struct block_device *bdev = I_BDEV(bdev_file_inode(file));
1768 0 : loff_t end = start + len - 1;
1769 0 : loff_t isize;
1770 0 : int error;
1771 :
1772 : /* Fail if we don't recognize the flags. */
1773 0 : if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
1774 : return -EOPNOTSUPP;
1775 :
1776 : /* Don't go off the end of the device. */
1777 0 : isize = i_size_read(bdev->bd_inode);
1778 0 : if (start >= isize)
1779 : return -EINVAL;
1780 0 : if (end >= isize) {
1781 0 : if (mode & FALLOC_FL_KEEP_SIZE) {
1782 0 : len = isize - start;
1783 0 : end = start + len - 1;
1784 : } else
1785 : return -EINVAL;
1786 : }
1787 :
1788 : /*
1789 : * Don't allow IO that isn't aligned to logical block size.
1790 : */
1791 0 : if ((start | len) & (bdev_logical_block_size(bdev) - 1))
1792 : return -EINVAL;
1793 :
1794 : /* Invalidate the page cache, including dirty pages. */
1795 0 : error = truncate_bdev_range(bdev, file->f_mode, start, end);
1796 0 : if (error)
1797 0 : return error;
1798 :
1799 0 : switch (mode) {
1800 0 : case FALLOC_FL_ZERO_RANGE:
1801 : case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
1802 0 : error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9,
1803 : GFP_KERNEL, BLKDEV_ZERO_NOUNMAP);
1804 0 : break;
1805 0 : case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
1806 0 : error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9,
1807 : GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK);
1808 0 : break;
1809 0 : case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
1810 0 : error = blkdev_issue_discard(bdev, start >> 9, len >> 9,
1811 : GFP_KERNEL, 0);
1812 0 : break;
1813 : default:
1814 : return -EOPNOTSUPP;
1815 : }
1816 0 : if (error)
1817 0 : return error;
1818 :
1819 : /*
1820 : * Invalidate the page cache again; if someone wandered in and dirtied
1821 : * a page, we just discard it - userspace has no way of knowing whether
1822 : * the write happened before or after discard completing...
1823 : */
1824 0 : return truncate_bdev_range(bdev, file->f_mode, start, end);
1825 : }
1826 :
1827 : const struct file_operations def_blk_fops = {
1828 : .open = blkdev_open,
1829 : .release = blkdev_close,
1830 : .llseek = block_llseek,
1831 : .read_iter = blkdev_read_iter,
1832 : .write_iter = blkdev_write_iter,
1833 : .iopoll = blkdev_iopoll,
1834 : .mmap = generic_file_mmap,
1835 : .fsync = blkdev_fsync,
1836 : .unlocked_ioctl = block_ioctl,
1837 : #ifdef CONFIG_COMPAT
1838 : .compat_ioctl = compat_blkdev_ioctl,
1839 : #endif
1840 : .splice_read = generic_file_splice_read,
1841 : .splice_write = iter_file_splice_write,
1842 : .fallocate = blkdev_fallocate,
1843 : };
1844 :
1845 : /**
1846 : * lookup_bdev - lookup a struct block_device by name
1847 : * @pathname: special file representing the block device
1848 : * @dev: return value of the block device's dev_t
1849 : *
1850 : * Get a reference to the blockdevice at @pathname in the current
1851 : * namespace if possible and return it. Return ERR_PTR(error)
1852 : * otherwise.
1853 : */
1854 2 : int lookup_bdev(const char *pathname, dev_t *dev)
1855 : {
1856 2 : struct inode *inode;
1857 2 : struct path path;
1858 2 : int error;
1859 :
1860 2 : if (!pathname || !*pathname)
1861 : return -EINVAL;
1862 :
1863 2 : error = kern_path(pathname, LOOKUP_FOLLOW, &path);
1864 2 : if (error)
1865 : return error;
1866 :
1867 2 : inode = d_backing_inode(path.dentry);
1868 2 : error = -ENOTBLK;
1869 2 : if (!S_ISBLK(inode->i_mode))
1870 0 : goto out_path_put;
1871 2 : error = -EACCES;
1872 2 : if (!may_open_dev(&path))
1873 0 : goto out_path_put;
1874 :
1875 2 : *dev = inode->i_rdev;
1876 2 : error = 0;
1877 2 : out_path_put:
1878 2 : path_put(&path);
1879 2 : return error;
1880 : }
1881 : EXPORT_SYMBOL(lookup_bdev);
1882 :
1883 0 : int __invalidate_device(struct block_device *bdev, bool kill_dirty)
1884 : {
1885 0 : struct super_block *sb = get_super(bdev);
1886 0 : int res = 0;
1887 :
1888 0 : if (sb) {
1889 : /*
1890 : * no need to lock the super, get_super holds the
1891 : * read mutex so the filesystem cannot go away
1892 : * under us (->put_super runs with the write lock
1893 : * hold).
1894 : */
1895 0 : shrink_dcache_sb(sb);
1896 0 : res = invalidate_inodes(sb, kill_dirty);
1897 0 : drop_super(sb);
1898 : }
1899 0 : invalidate_bdev(bdev);
1900 0 : return res;
1901 : }
1902 : EXPORT_SYMBOL(__invalidate_device);
1903 :
1904 0 : void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg)
1905 : {
1906 0 : struct inode *inode, *old_inode = NULL;
1907 :
1908 0 : spin_lock(&blockdev_superblock->s_inode_list_lock);
1909 0 : list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) {
1910 0 : struct address_space *mapping = inode->i_mapping;
1911 0 : struct block_device *bdev;
1912 :
1913 0 : spin_lock(&inode->i_lock);
1914 0 : if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) ||
1915 0 : mapping->nrpages == 0) {
1916 0 : spin_unlock(&inode->i_lock);
1917 0 : continue;
1918 : }
1919 0 : __iget(inode);
1920 0 : spin_unlock(&inode->i_lock);
1921 0 : spin_unlock(&blockdev_superblock->s_inode_list_lock);
1922 : /*
1923 : * We hold a reference to 'inode' so it couldn't have been
1924 : * removed from s_inodes list while we dropped the
1925 : * s_inode_list_lock We cannot iput the inode now as we can
1926 : * be holding the last reference and we cannot iput it under
1927 : * s_inode_list_lock. So we keep the reference and iput it
1928 : * later.
1929 : */
1930 0 : iput(old_inode);
1931 0 : old_inode = inode;
1932 0 : bdev = I_BDEV(inode);
1933 :
1934 0 : mutex_lock(&bdev->bd_mutex);
1935 0 : if (bdev->bd_openers)
1936 0 : func(bdev, arg);
1937 0 : mutex_unlock(&bdev->bd_mutex);
1938 :
1939 0 : spin_lock(&blockdev_superblock->s_inode_list_lock);
1940 : }
1941 0 : spin_unlock(&blockdev_superblock->s_inode_list_lock);
1942 0 : iput(old_inode);
1943 0 : }
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