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1 | /* | |
2 | * linux/fs/block_dev.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE | |
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/uio.h> | |
28 | #include <linux/namei.h> | |
29 | #include <linux/log2.h> | |
30 | #include <linux/cleancache.h> | |
31 | #include <linux/dax.h> | |
32 | #include <linux/badblocks.h> | |
33 | #include <linux/task_io_accounting_ops.h> | |
34 | #include <linux/falloc.h> | |
35 | #include <linux/uaccess.h> | |
36 | #include "internal.h" | |
37 | ||
38 | struct bdev_inode { | |
39 | struct block_device bdev; | |
40 | struct inode vfs_inode; | |
41 | }; | |
42 | ||
43 | static const struct address_space_operations def_blk_aops; | |
44 | ||
45 | static inline struct bdev_inode *BDEV_I(struct inode *inode) | |
46 | { | |
47 | return container_of(inode, struct bdev_inode, vfs_inode); | |
48 | } | |
49 | ||
50 | struct block_device *I_BDEV(struct inode *inode) | |
51 | { | |
52 | return &BDEV_I(inode)->bdev; | |
53 | } | |
54 | EXPORT_SYMBOL(I_BDEV); | |
55 | ||
56 | void __vfs_msg(struct super_block *sb, const char *prefix, const char *fmt, ...) | |
57 | { | |
58 | struct va_format vaf; | |
59 | va_list args; | |
60 | ||
61 | va_start(args, fmt); | |
62 | vaf.fmt = fmt; | |
63 | vaf.va = &args; | |
64 | printk_ratelimited("%sVFS (%s): %pV\n", prefix, sb->s_id, &vaf); | |
65 | va_end(args); | |
66 | } | |
67 | ||
68 | static void bdev_write_inode(struct block_device *bdev) | |
69 | { | |
70 | struct inode *inode = bdev->bd_inode; | |
71 | int ret; | |
72 | ||
73 | spin_lock(&inode->i_lock); | |
74 | while (inode->i_state & I_DIRTY) { | |
75 | spin_unlock(&inode->i_lock); | |
76 | ret = write_inode_now(inode, true); | |
77 | if (ret) { | |
78 | char name[BDEVNAME_SIZE]; | |
79 | pr_warn_ratelimited("VFS: Dirty inode writeback failed " | |
80 | "for block device %s (err=%d).\n", | |
81 | bdevname(bdev, name), ret); | |
82 | } | |
83 | spin_lock(&inode->i_lock); | |
84 | } | |
85 | spin_unlock(&inode->i_lock); | |
86 | } | |
87 | ||
88 | /* Kill _all_ buffers and pagecache , dirty or not.. */ | |
89 | void kill_bdev(struct block_device *bdev) | |
90 | { | |
91 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
92 | ||
93 | if (mapping->nrpages == 0 && mapping->nrexceptional == 0) | |
94 | return; | |
95 | ||
96 | invalidate_bh_lrus(); | |
97 | truncate_inode_pages(mapping, 0); | |
98 | } | |
99 | EXPORT_SYMBOL(kill_bdev); | |
100 | ||
101 | /* Invalidate clean unused buffers and pagecache. */ | |
102 | void invalidate_bdev(struct block_device *bdev) | |
103 | { | |
104 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
105 | ||
106 | if (mapping->nrpages) { | |
107 | invalidate_bh_lrus(); | |
108 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ | |
109 | invalidate_mapping_pages(mapping, 0, -1); | |
110 | } | |
111 | /* 99% of the time, we don't need to flush the cleancache on the bdev. | |
112 | * But, for the strange corners, lets be cautious | |
113 | */ | |
114 | cleancache_invalidate_inode(mapping); | |
115 | } | |
116 | EXPORT_SYMBOL(invalidate_bdev); | |
117 | ||
118 | int set_blocksize(struct block_device *bdev, int size) | |
119 | { | |
120 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
121 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) | |
122 | return -EINVAL; | |
123 | ||
124 | /* Size cannot be smaller than the size supported by the device */ | |
125 | if (size < bdev_logical_block_size(bdev)) | |
126 | return -EINVAL; | |
127 | ||
128 | /* Don't change the size if it is same as current */ | |
129 | if (bdev->bd_block_size != size) { | |
130 | sync_blockdev(bdev); | |
131 | bdev->bd_block_size = size; | |
132 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
133 | kill_bdev(bdev); | |
134 | } | |
135 | return 0; | |
136 | } | |
137 | ||
138 | EXPORT_SYMBOL(set_blocksize); | |
139 | ||
140 | int sb_set_blocksize(struct super_block *sb, int size) | |
141 | { | |
142 | if (set_blocksize(sb->s_bdev, size)) | |
143 | return 0; | |
144 | /* If we get here, we know size is power of two | |
145 | * and it's value is between 512 and PAGE_SIZE */ | |
146 | sb->s_blocksize = size; | |
147 | sb->s_blocksize_bits = blksize_bits(size); | |
148 | return sb->s_blocksize; | |
149 | } | |
150 | ||
151 | EXPORT_SYMBOL(sb_set_blocksize); | |
152 | ||
153 | int sb_min_blocksize(struct super_block *sb, int size) | |
154 | { | |
155 | int minsize = bdev_logical_block_size(sb->s_bdev); | |
156 | if (size < minsize) | |
157 | size = minsize; | |
158 | return sb_set_blocksize(sb, size); | |
159 | } | |
160 | ||
161 | EXPORT_SYMBOL(sb_min_blocksize); | |
162 | ||
163 | static int | |
164 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
165 | struct buffer_head *bh, int create) | |
166 | { | |
167 | bh->b_bdev = I_BDEV(inode); | |
168 | bh->b_blocknr = iblock; | |
169 | set_buffer_mapped(bh); | |
170 | return 0; | |
171 | } | |
172 | ||
173 | static struct inode *bdev_file_inode(struct file *file) | |
174 | { | |
175 | return file->f_mapping->host; | |
176 | } | |
177 | ||
178 | static unsigned int dio_bio_write_op(struct kiocb *iocb) | |
179 | { | |
180 | unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; | |
181 | ||
182 | /* avoid the need for a I/O completion work item */ | |
183 | if (iocb->ki_flags & IOCB_DSYNC) | |
184 | op |= REQ_FUA; | |
185 | return op; | |
186 | } | |
187 | ||
188 | #define DIO_INLINE_BIO_VECS 4 | |
189 | ||
190 | static void blkdev_bio_end_io_simple(struct bio *bio) | |
191 | { | |
192 | struct task_struct *waiter = bio->bi_private; | |
193 | ||
194 | WRITE_ONCE(bio->bi_private, NULL); | |
195 | wake_up_process(waiter); | |
196 | } | |
197 | ||
198 | static ssize_t | |
199 | __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, | |
200 | int nr_pages) | |
201 | { | |
202 | struct file *file = iocb->ki_filp; | |
203 | struct block_device *bdev = I_BDEV(bdev_file_inode(file)); | |
204 | struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs, *bvec; | |
205 | loff_t pos = iocb->ki_pos; | |
206 | bool should_dirty = false; | |
207 | struct bio bio; | |
208 | ssize_t ret; | |
209 | blk_qc_t qc; | |
210 | int i; | |
211 | ||
212 | if ((pos | iov_iter_alignment(iter)) & | |
213 | (bdev_logical_block_size(bdev) - 1)) | |
214 | return -EINVAL; | |
215 | ||
216 | if (nr_pages <= DIO_INLINE_BIO_VECS) | |
217 | vecs = inline_vecs; | |
218 | else { | |
219 | vecs = kmalloc(nr_pages * sizeof(struct bio_vec), GFP_KERNEL); | |
220 | if (!vecs) | |
221 | return -ENOMEM; | |
222 | } | |
223 | ||
224 | bio_init(&bio, vecs, nr_pages); | |
225 | bio.bi_bdev = bdev; | |
226 | bio.bi_iter.bi_sector = pos >> 9; | |
227 | bio.bi_private = current; | |
228 | bio.bi_end_io = blkdev_bio_end_io_simple; | |
229 | ||
230 | ret = bio_iov_iter_get_pages(&bio, iter); | |
231 | if (unlikely(ret)) | |
232 | return ret; | |
233 | ret = bio.bi_iter.bi_size; | |
234 | ||
235 | if (iov_iter_rw(iter) == READ) { | |
236 | bio.bi_opf = REQ_OP_READ; | |
237 | if (iter_is_iovec(iter)) | |
238 | should_dirty = true; | |
239 | } else { | |
240 | bio.bi_opf = dio_bio_write_op(iocb); | |
241 | task_io_account_write(ret); | |
242 | } | |
243 | ||
244 | qc = submit_bio(&bio); | |
245 | for (;;) { | |
246 | set_current_state(TASK_UNINTERRUPTIBLE); | |
247 | if (!READ_ONCE(bio.bi_private)) | |
248 | break; | |
249 | if (!(iocb->ki_flags & IOCB_HIPRI) || | |
250 | !blk_mq_poll(bdev_get_queue(bdev), qc)) | |
251 | io_schedule(); | |
252 | } | |
253 | __set_current_state(TASK_RUNNING); | |
254 | ||
255 | bio_for_each_segment_all(bvec, &bio, i) { | |
256 | if (should_dirty && !PageCompound(bvec->bv_page)) | |
257 | set_page_dirty_lock(bvec->bv_page); | |
258 | put_page(bvec->bv_page); | |
259 | } | |
260 | ||
261 | if (vecs != inline_vecs) | |
262 | kfree(vecs); | |
263 | ||
264 | if (unlikely(bio.bi_error)) | |
265 | return bio.bi_error; | |
266 | return ret; | |
267 | } | |
268 | ||
269 | struct blkdev_dio { | |
270 | union { | |
271 | struct kiocb *iocb; | |
272 | struct task_struct *waiter; | |
273 | }; | |
274 | size_t size; | |
275 | atomic_t ref; | |
276 | bool multi_bio : 1; | |
277 | bool should_dirty : 1; | |
278 | bool is_sync : 1; | |
279 | struct bio bio; | |
280 | }; | |
281 | ||
282 | static struct bio_set *blkdev_dio_pool __read_mostly; | |
283 | ||
284 | static void blkdev_bio_end_io(struct bio *bio) | |
285 | { | |
286 | struct blkdev_dio *dio = bio->bi_private; | |
287 | bool should_dirty = dio->should_dirty; | |
288 | ||
289 | if (dio->multi_bio && !atomic_dec_and_test(&dio->ref)) { | |
290 | if (bio->bi_error && !dio->bio.bi_error) | |
291 | dio->bio.bi_error = bio->bi_error; | |
292 | } else { | |
293 | if (!dio->is_sync) { | |
294 | struct kiocb *iocb = dio->iocb; | |
295 | ssize_t ret = dio->bio.bi_error; | |
296 | ||
297 | if (likely(!ret)) { | |
298 | ret = dio->size; | |
299 | iocb->ki_pos += ret; | |
300 | } | |
301 | ||
302 | dio->iocb->ki_complete(iocb, ret, 0); | |
303 | bio_put(&dio->bio); | |
304 | } else { | |
305 | struct task_struct *waiter = dio->waiter; | |
306 | ||
307 | WRITE_ONCE(dio->waiter, NULL); | |
308 | wake_up_process(waiter); | |
309 | } | |
310 | } | |
311 | ||
312 | if (should_dirty) { | |
313 | bio_check_pages_dirty(bio); | |
314 | } else { | |
315 | struct bio_vec *bvec; | |
316 | int i; | |
317 | ||
318 | bio_for_each_segment_all(bvec, bio, i) | |
319 | put_page(bvec->bv_page); | |
320 | bio_put(bio); | |
321 | } | |
322 | } | |
323 | ||
324 | static ssize_t | |
325 | __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) | |
326 | { | |
327 | struct file *file = iocb->ki_filp; | |
328 | struct inode *inode = bdev_file_inode(file); | |
329 | struct block_device *bdev = I_BDEV(inode); | |
330 | struct blk_plug plug; | |
331 | struct blkdev_dio *dio; | |
332 | struct bio *bio; | |
333 | bool is_read = (iov_iter_rw(iter) == READ), is_sync; | |
334 | loff_t pos = iocb->ki_pos; | |
335 | blk_qc_t qc = BLK_QC_T_NONE; | |
336 | int ret; | |
337 | ||
338 | if ((pos | iov_iter_alignment(iter)) & | |
339 | (bdev_logical_block_size(bdev) - 1)) | |
340 | return -EINVAL; | |
341 | ||
342 | bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, blkdev_dio_pool); | |
343 | bio_get(bio); /* extra ref for the completion handler */ | |
344 | ||
345 | dio = container_of(bio, struct blkdev_dio, bio); | |
346 | dio->is_sync = is_sync = is_sync_kiocb(iocb); | |
347 | if (dio->is_sync) | |
348 | dio->waiter = current; | |
349 | else | |
350 | dio->iocb = iocb; | |
351 | ||
352 | dio->size = 0; | |
353 | dio->multi_bio = false; | |
354 | dio->should_dirty = is_read && (iter->type == ITER_IOVEC); | |
355 | ||
356 | blk_start_plug(&plug); | |
357 | for (;;) { | |
358 | bio->bi_bdev = bdev; | |
359 | bio->bi_iter.bi_sector = pos >> 9; | |
360 | bio->bi_private = dio; | |
361 | bio->bi_end_io = blkdev_bio_end_io; | |
362 | ||
363 | ret = bio_iov_iter_get_pages(bio, iter); | |
364 | if (unlikely(ret)) { | |
365 | bio->bi_error = ret; | |
366 | bio_endio(bio); | |
367 | break; | |
368 | } | |
369 | ||
370 | if (is_read) { | |
371 | bio->bi_opf = REQ_OP_READ; | |
372 | if (dio->should_dirty) | |
373 | bio_set_pages_dirty(bio); | |
374 | } else { | |
375 | bio->bi_opf = dio_bio_write_op(iocb); | |
376 | task_io_account_write(bio->bi_iter.bi_size); | |
377 | } | |
378 | ||
379 | dio->size += bio->bi_iter.bi_size; | |
380 | pos += bio->bi_iter.bi_size; | |
381 | ||
382 | nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); | |
383 | if (!nr_pages) { | |
384 | qc = submit_bio(bio); | |
385 | break; | |
386 | } | |
387 | ||
388 | if (!dio->multi_bio) { | |
389 | dio->multi_bio = true; | |
390 | atomic_set(&dio->ref, 2); | |
391 | } else { | |
392 | atomic_inc(&dio->ref); | |
393 | } | |
394 | ||
395 | submit_bio(bio); | |
396 | bio = bio_alloc(GFP_KERNEL, nr_pages); | |
397 | } | |
398 | blk_finish_plug(&plug); | |
399 | ||
400 | if (!is_sync) | |
401 | return -EIOCBQUEUED; | |
402 | ||
403 | for (;;) { | |
404 | set_current_state(TASK_UNINTERRUPTIBLE); | |
405 | if (!READ_ONCE(dio->waiter)) | |
406 | break; | |
407 | ||
408 | if (!(iocb->ki_flags & IOCB_HIPRI) || | |
409 | !blk_mq_poll(bdev_get_queue(bdev), qc)) | |
410 | io_schedule(); | |
411 | } | |
412 | __set_current_state(TASK_RUNNING); | |
413 | ||
414 | ret = dio->bio.bi_error; | |
415 | if (likely(!ret)) | |
416 | ret = dio->size; | |
417 | ||
418 | bio_put(&dio->bio); | |
419 | return ret; | |
420 | } | |
421 | ||
422 | static ssize_t | |
423 | blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) | |
424 | { | |
425 | int nr_pages; | |
426 | ||
427 | nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES + 1); | |
428 | if (!nr_pages) | |
429 | return 0; | |
430 | if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_PAGES) | |
431 | return __blkdev_direct_IO_simple(iocb, iter, nr_pages); | |
432 | ||
433 | return __blkdev_direct_IO(iocb, iter, min(nr_pages, BIO_MAX_PAGES)); | |
434 | } | |
435 | ||
436 | static __init int blkdev_init(void) | |
437 | { | |
438 | blkdev_dio_pool = bioset_create(4, offsetof(struct blkdev_dio, bio)); | |
439 | if (!blkdev_dio_pool) | |
440 | return -ENOMEM; | |
441 | return 0; | |
442 | } | |
443 | module_init(blkdev_init); | |
444 | ||
445 | int __sync_blockdev(struct block_device *bdev, int wait) | |
446 | { | |
447 | if (!bdev) | |
448 | return 0; | |
449 | if (!wait) | |
450 | return filemap_flush(bdev->bd_inode->i_mapping); | |
451 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
452 | } | |
453 | ||
454 | /* | |
455 | * Write out and wait upon all the dirty data associated with a block | |
456 | * device via its mapping. Does not take the superblock lock. | |
457 | */ | |
458 | int sync_blockdev(struct block_device *bdev) | |
459 | { | |
460 | return __sync_blockdev(bdev, 1); | |
461 | } | |
462 | EXPORT_SYMBOL(sync_blockdev); | |
463 | ||
464 | /* | |
465 | * Write out and wait upon all dirty data associated with this | |
466 | * device. Filesystem data as well as the underlying block | |
467 | * device. Takes the superblock lock. | |
468 | */ | |
469 | int fsync_bdev(struct block_device *bdev) | |
470 | { | |
471 | struct super_block *sb = get_super(bdev); | |
472 | if (sb) { | |
473 | int res = sync_filesystem(sb); | |
474 | drop_super(sb); | |
475 | return res; | |
476 | } | |
477 | return sync_blockdev(bdev); | |
478 | } | |
479 | EXPORT_SYMBOL(fsync_bdev); | |
480 | ||
481 | /** | |
482 | * freeze_bdev -- lock a filesystem and force it into a consistent state | |
483 | * @bdev: blockdevice to lock | |
484 | * | |
485 | * If a superblock is found on this device, we take the s_umount semaphore | |
486 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
487 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
488 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
489 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and | |
490 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze | |
491 | * actually. | |
492 | */ | |
493 | struct super_block *freeze_bdev(struct block_device *bdev) | |
494 | { | |
495 | struct super_block *sb; | |
496 | int error = 0; | |
497 | ||
498 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
499 | if (++bdev->bd_fsfreeze_count > 1) { | |
500 | /* | |
501 | * We don't even need to grab a reference - the first call | |
502 | * to freeze_bdev grab an active reference and only the last | |
503 | * thaw_bdev drops it. | |
504 | */ | |
505 | sb = get_super(bdev); | |
506 | if (sb) | |
507 | drop_super(sb); | |
508 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
509 | return sb; | |
510 | } | |
511 | ||
512 | sb = get_active_super(bdev); | |
513 | if (!sb) | |
514 | goto out; | |
515 | if (sb->s_op->freeze_super) | |
516 | error = sb->s_op->freeze_super(sb); | |
517 | else | |
518 | error = freeze_super(sb); | |
519 | if (error) { | |
520 | deactivate_super(sb); | |
521 | bdev->bd_fsfreeze_count--; | |
522 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
523 | return ERR_PTR(error); | |
524 | } | |
525 | deactivate_super(sb); | |
526 | out: | |
527 | sync_blockdev(bdev); | |
528 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
529 | return sb; /* thaw_bdev releases s->s_umount */ | |
530 | } | |
531 | EXPORT_SYMBOL(freeze_bdev); | |
532 | ||
533 | /** | |
534 | * thaw_bdev -- unlock filesystem | |
535 | * @bdev: blockdevice to unlock | |
536 | * @sb: associated superblock | |
537 | * | |
538 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). | |
539 | */ | |
540 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) | |
541 | { | |
542 | int error = -EINVAL; | |
543 | ||
544 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
545 | if (!bdev->bd_fsfreeze_count) | |
546 | goto out; | |
547 | ||
548 | error = 0; | |
549 | if (--bdev->bd_fsfreeze_count > 0) | |
550 | goto out; | |
551 | ||
552 | if (!sb) | |
553 | goto out; | |
554 | ||
555 | if (sb->s_op->thaw_super) | |
556 | error = sb->s_op->thaw_super(sb); | |
557 | else | |
558 | error = thaw_super(sb); | |
559 | if (error) | |
560 | bdev->bd_fsfreeze_count++; | |
561 | out: | |
562 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
563 | return error; | |
564 | } | |
565 | EXPORT_SYMBOL(thaw_bdev); | |
566 | ||
567 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) | |
568 | { | |
569 | return block_write_full_page(page, blkdev_get_block, wbc); | |
570 | } | |
571 | ||
572 | static int blkdev_readpage(struct file * file, struct page * page) | |
573 | { | |
574 | return block_read_full_page(page, blkdev_get_block); | |
575 | } | |
576 | ||
577 | static int blkdev_readpages(struct file *file, struct address_space *mapping, | |
578 | struct list_head *pages, unsigned nr_pages) | |
579 | { | |
580 | return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); | |
581 | } | |
582 | ||
583 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, | |
584 | loff_t pos, unsigned len, unsigned flags, | |
585 | struct page **pagep, void **fsdata) | |
586 | { | |
587 | return block_write_begin(mapping, pos, len, flags, pagep, | |
588 | blkdev_get_block); | |
589 | } | |
590 | ||
591 | static int blkdev_write_end(struct file *file, struct address_space *mapping, | |
592 | loff_t pos, unsigned len, unsigned copied, | |
593 | struct page *page, void *fsdata) | |
594 | { | |
595 | int ret; | |
596 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); | |
597 | ||
598 | unlock_page(page); | |
599 | put_page(page); | |
600 | ||
601 | return ret; | |
602 | } | |
603 | ||
604 | /* | |
605 | * private llseek: | |
606 | * for a block special file file_inode(file)->i_size is zero | |
607 | * so we compute the size by hand (just as in block_read/write above) | |
608 | */ | |
609 | static loff_t block_llseek(struct file *file, loff_t offset, int whence) | |
610 | { | |
611 | struct inode *bd_inode = bdev_file_inode(file); | |
612 | loff_t retval; | |
613 | ||
614 | inode_lock(bd_inode); | |
615 | retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); | |
616 | inode_unlock(bd_inode); | |
617 | return retval; | |
618 | } | |
619 | ||
620 | int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) | |
621 | { | |
622 | struct inode *bd_inode = bdev_file_inode(filp); | |
623 | struct block_device *bdev = I_BDEV(bd_inode); | |
624 | int error; | |
625 | ||
626 | error = filemap_write_and_wait_range(filp->f_mapping, start, end); | |
627 | if (error) | |
628 | return error; | |
629 | ||
630 | /* | |
631 | * There is no need to serialise calls to blkdev_issue_flush with | |
632 | * i_mutex and doing so causes performance issues with concurrent | |
633 | * O_SYNC writers to a block device. | |
634 | */ | |
635 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); | |
636 | if (error == -EOPNOTSUPP) | |
637 | error = 0; | |
638 | ||
639 | return error; | |
640 | } | |
641 | EXPORT_SYMBOL(blkdev_fsync); | |
642 | ||
643 | /** | |
644 | * bdev_read_page() - Start reading a page from a block device | |
645 | * @bdev: The device to read the page from | |
646 | * @sector: The offset on the device to read the page to (need not be aligned) | |
647 | * @page: The page to read | |
648 | * | |
649 | * On entry, the page should be locked. It will be unlocked when the page | |
650 | * has been read. If the block driver implements rw_page synchronously, | |
651 | * that will be true on exit from this function, but it need not be. | |
652 | * | |
653 | * Errors returned by this function are usually "soft", eg out of memory, or | |
654 | * queue full; callers should try a different route to read this page rather | |
655 | * than propagate an error back up the stack. | |
656 | * | |
657 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
658 | */ | |
659 | int bdev_read_page(struct block_device *bdev, sector_t sector, | |
660 | struct page *page) | |
661 | { | |
662 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
663 | int result = -EOPNOTSUPP; | |
664 | ||
665 | if (!ops->rw_page || bdev_get_integrity(bdev)) | |
666 | return result; | |
667 | ||
668 | result = blk_queue_enter(bdev->bd_queue, false); | |
669 | if (result) | |
670 | return result; | |
671 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, false); | |
672 | blk_queue_exit(bdev->bd_queue); | |
673 | return result; | |
674 | } | |
675 | EXPORT_SYMBOL_GPL(bdev_read_page); | |
676 | ||
677 | /** | |
678 | * bdev_write_page() - Start writing a page to a block device | |
679 | * @bdev: The device to write the page to | |
680 | * @sector: The offset on the device to write the page to (need not be aligned) | |
681 | * @page: The page to write | |
682 | * @wbc: The writeback_control for the write | |
683 | * | |
684 | * On entry, the page should be locked and not currently under writeback. | |
685 | * On exit, if the write started successfully, the page will be unlocked and | |
686 | * under writeback. If the write failed already (eg the driver failed to | |
687 | * queue the page to the device), the page will still be locked. If the | |
688 | * caller is a ->writepage implementation, it will need to unlock the page. | |
689 | * | |
690 | * Errors returned by this function are usually "soft", eg out of memory, or | |
691 | * queue full; callers should try a different route to write this page rather | |
692 | * than propagate an error back up the stack. | |
693 | * | |
694 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
695 | */ | |
696 | int bdev_write_page(struct block_device *bdev, sector_t sector, | |
697 | struct page *page, struct writeback_control *wbc) | |
698 | { | |
699 | int result; | |
700 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
701 | ||
702 | if (!ops->rw_page || bdev_get_integrity(bdev)) | |
703 | return -EOPNOTSUPP; | |
704 | result = blk_queue_enter(bdev->bd_queue, false); | |
705 | if (result) | |
706 | return result; | |
707 | ||
708 | set_page_writeback(page); | |
709 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, true); | |
710 | if (result) | |
711 | end_page_writeback(page); | |
712 | else | |
713 | unlock_page(page); | |
714 | blk_queue_exit(bdev->bd_queue); | |
715 | return result; | |
716 | } | |
717 | EXPORT_SYMBOL_GPL(bdev_write_page); | |
718 | ||
719 | /** | |
720 | * bdev_direct_access() - Get the address for directly-accessibly memory | |
721 | * @bdev: The device containing the memory | |
722 | * @dax: control and output parameters for ->direct_access | |
723 | * | |
724 | * If a block device is made up of directly addressable memory, this function | |
725 | * will tell the caller the PFN and the address of the memory. The address | |
726 | * may be directly dereferenced within the kernel without the need to call | |
727 | * ioremap(), kmap() or similar. The PFN is suitable for inserting into | |
728 | * page tables. | |
729 | * | |
730 | * Return: negative errno if an error occurs, otherwise the number of bytes | |
731 | * accessible at this address. | |
732 | */ | |
733 | long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) | |
734 | { | |
735 | sector_t sector = dax->sector; | |
736 | long avail, size = dax->size; | |
737 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
738 | ||
739 | /* | |
740 | * The device driver is allowed to sleep, in order to make the | |
741 | * memory directly accessible. | |
742 | */ | |
743 | might_sleep(); | |
744 | ||
745 | if (size < 0) | |
746 | return size; | |
747 | if (!blk_queue_dax(bdev_get_queue(bdev)) || !ops->direct_access) | |
748 | return -EOPNOTSUPP; | |
749 | if ((sector + DIV_ROUND_UP(size, 512)) > | |
750 | part_nr_sects_read(bdev->bd_part)) | |
751 | return -ERANGE; | |
752 | sector += get_start_sect(bdev); | |
753 | if (sector % (PAGE_SIZE / 512)) | |
754 | return -EINVAL; | |
755 | avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn, size); | |
756 | if (!avail) | |
757 | return -ERANGE; | |
758 | if (avail > 0 && avail & ~PAGE_MASK) | |
759 | return -ENXIO; | |
760 | return min(avail, size); | |
761 | } | |
762 | EXPORT_SYMBOL_GPL(bdev_direct_access); | |
763 | ||
764 | /** | |
765 | * bdev_dax_supported() - Check if the device supports dax for filesystem | |
766 | * @sb: The superblock of the device | |
767 | * @blocksize: The block size of the device | |
768 | * | |
769 | * This is a library function for filesystems to check if the block device | |
770 | * can be mounted with dax option. | |
771 | * | |
772 | * Return: negative errno if unsupported, 0 if supported. | |
773 | */ | |
774 | int bdev_dax_supported(struct super_block *sb, int blocksize) | |
775 | { | |
776 | struct blk_dax_ctl dax = { | |
777 | .sector = 0, | |
778 | .size = PAGE_SIZE, | |
779 | }; | |
780 | int err; | |
781 | ||
782 | if (blocksize != PAGE_SIZE) { | |
783 | vfs_msg(sb, KERN_ERR, "error: unsupported blocksize for dax"); | |
784 | return -EINVAL; | |
785 | } | |
786 | ||
787 | err = bdev_direct_access(sb->s_bdev, &dax); | |
788 | if (err < 0) { | |
789 | switch (err) { | |
790 | case -EOPNOTSUPP: | |
791 | vfs_msg(sb, KERN_ERR, | |
792 | "error: device does not support dax"); | |
793 | break; | |
794 | case -EINVAL: | |
795 | vfs_msg(sb, KERN_ERR, | |
796 | "error: unaligned partition for dax"); | |
797 | break; | |
798 | default: | |
799 | vfs_msg(sb, KERN_ERR, | |
800 | "error: dax access failed (%d)", err); | |
801 | } | |
802 | return err; | |
803 | } | |
804 | ||
805 | return 0; | |
806 | } | |
807 | EXPORT_SYMBOL_GPL(bdev_dax_supported); | |
808 | ||
809 | /** | |
810 | * bdev_dax_capable() - Return if the raw device is capable for dax | |
811 | * @bdev: The device for raw block device access | |
812 | */ | |
813 | bool bdev_dax_capable(struct block_device *bdev) | |
814 | { | |
815 | struct blk_dax_ctl dax = { | |
816 | .size = PAGE_SIZE, | |
817 | }; | |
818 | ||
819 | if (!IS_ENABLED(CONFIG_FS_DAX)) | |
820 | return false; | |
821 | ||
822 | dax.sector = 0; | |
823 | if (bdev_direct_access(bdev, &dax) < 0) | |
824 | return false; | |
825 | ||
826 | dax.sector = bdev->bd_part->nr_sects - (PAGE_SIZE / 512); | |
827 | if (bdev_direct_access(bdev, &dax) < 0) | |
828 | return false; | |
829 | ||
830 | return true; | |
831 | } | |
832 | ||
833 | /* | |
834 | * pseudo-fs | |
835 | */ | |
836 | ||
837 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
838 | static struct kmem_cache * bdev_cachep __read_mostly; | |
839 | ||
840 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
841 | { | |
842 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); | |
843 | if (!ei) | |
844 | return NULL; | |
845 | return &ei->vfs_inode; | |
846 | } | |
847 | ||
848 | static void bdev_i_callback(struct rcu_head *head) | |
849 | { | |
850 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
851 | struct bdev_inode *bdi = BDEV_I(inode); | |
852 | ||
853 | kmem_cache_free(bdev_cachep, bdi); | |
854 | } | |
855 | ||
856 | static void bdev_destroy_inode(struct inode *inode) | |
857 | { | |
858 | call_rcu(&inode->i_rcu, bdev_i_callback); | |
859 | } | |
860 | ||
861 | static void init_once(void *foo) | |
862 | { | |
863 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
864 | struct block_device *bdev = &ei->bdev; | |
865 | ||
866 | memset(bdev, 0, sizeof(*bdev)); | |
867 | mutex_init(&bdev->bd_mutex); | |
868 | INIT_LIST_HEAD(&bdev->bd_list); | |
869 | #ifdef CONFIG_SYSFS | |
870 | INIT_LIST_HEAD(&bdev->bd_holder_disks); | |
871 | #endif | |
872 | inode_init_once(&ei->vfs_inode); | |
873 | /* Initialize mutex for freeze. */ | |
874 | mutex_init(&bdev->bd_fsfreeze_mutex); | |
875 | } | |
876 | ||
877 | static void bdev_evict_inode(struct inode *inode) | |
878 | { | |
879 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
880 | truncate_inode_pages_final(&inode->i_data); | |
881 | invalidate_inode_buffers(inode); /* is it needed here? */ | |
882 | clear_inode(inode); | |
883 | spin_lock(&bdev_lock); | |
884 | list_del_init(&bdev->bd_list); | |
885 | spin_unlock(&bdev_lock); | |
886 | } | |
887 | ||
888 | static const struct super_operations bdev_sops = { | |
889 | .statfs = simple_statfs, | |
890 | .alloc_inode = bdev_alloc_inode, | |
891 | .destroy_inode = bdev_destroy_inode, | |
892 | .drop_inode = generic_delete_inode, | |
893 | .evict_inode = bdev_evict_inode, | |
894 | }; | |
895 | ||
896 | static struct dentry *bd_mount(struct file_system_type *fs_type, | |
897 | int flags, const char *dev_name, void *data) | |
898 | { | |
899 | struct dentry *dent; | |
900 | dent = mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC); | |
901 | if (!IS_ERR(dent)) | |
902 | dent->d_sb->s_iflags |= SB_I_CGROUPWB; | |
903 | return dent; | |
904 | } | |
905 | ||
906 | static struct file_system_type bd_type = { | |
907 | .name = "bdev", | |
908 | .mount = bd_mount, | |
909 | .kill_sb = kill_anon_super, | |
910 | }; | |
911 | ||
912 | struct super_block *blockdev_superblock __read_mostly; | |
913 | EXPORT_SYMBOL_GPL(blockdev_superblock); | |
914 | ||
915 | void __init bdev_cache_init(void) | |
916 | { | |
917 | int err; | |
918 | static struct vfsmount *bd_mnt; | |
919 | ||
920 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), | |
921 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| | |
922 | SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), | |
923 | init_once); | |
924 | err = register_filesystem(&bd_type); | |
925 | if (err) | |
926 | panic("Cannot register bdev pseudo-fs"); | |
927 | bd_mnt = kern_mount(&bd_type); | |
928 | if (IS_ERR(bd_mnt)) | |
929 | panic("Cannot create bdev pseudo-fs"); | |
930 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ | |
931 | } | |
932 | ||
933 | /* | |
934 | * Most likely _very_ bad one - but then it's hardly critical for small | |
935 | * /dev and can be fixed when somebody will need really large one. | |
936 | * Keep in mind that it will be fed through icache hash function too. | |
937 | */ | |
938 | static inline unsigned long hash(dev_t dev) | |
939 | { | |
940 | return MAJOR(dev)+MINOR(dev); | |
941 | } | |
942 | ||
943 | static int bdev_test(struct inode *inode, void *data) | |
944 | { | |
945 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
946 | } | |
947 | ||
948 | static int bdev_set(struct inode *inode, void *data) | |
949 | { | |
950 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
951 | return 0; | |
952 | } | |
953 | ||
954 | static LIST_HEAD(all_bdevs); | |
955 | ||
956 | struct block_device *bdget(dev_t dev) | |
957 | { | |
958 | struct block_device *bdev; | |
959 | struct inode *inode; | |
960 | ||
961 | inode = iget5_locked(blockdev_superblock, hash(dev), | |
962 | bdev_test, bdev_set, &dev); | |
963 | ||
964 | if (!inode) | |
965 | return NULL; | |
966 | ||
967 | bdev = &BDEV_I(inode)->bdev; | |
968 | ||
969 | if (inode->i_state & I_NEW) { | |
970 | bdev->bd_contains = NULL; | |
971 | bdev->bd_super = NULL; | |
972 | bdev->bd_inode = inode; | |
973 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
974 | bdev->bd_part_count = 0; | |
975 | bdev->bd_invalidated = 0; | |
976 | inode->i_mode = S_IFBLK; | |
977 | inode->i_rdev = dev; | |
978 | inode->i_bdev = bdev; | |
979 | inode->i_data.a_ops = &def_blk_aops; | |
980 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
981 | spin_lock(&bdev_lock); | |
982 | list_add(&bdev->bd_list, &all_bdevs); | |
983 | spin_unlock(&bdev_lock); | |
984 | unlock_new_inode(inode); | |
985 | } | |
986 | return bdev; | |
987 | } | |
988 | ||
989 | EXPORT_SYMBOL(bdget); | |
990 | ||
991 | /** | |
992 | * bdgrab -- Grab a reference to an already referenced block device | |
993 | * @bdev: Block device to grab a reference to. | |
994 | */ | |
995 | struct block_device *bdgrab(struct block_device *bdev) | |
996 | { | |
997 | ihold(bdev->bd_inode); | |
998 | return bdev; | |
999 | } | |
1000 | EXPORT_SYMBOL(bdgrab); | |
1001 | ||
1002 | long nr_blockdev_pages(void) | |
1003 | { | |
1004 | struct block_device *bdev; | |
1005 | long ret = 0; | |
1006 | spin_lock(&bdev_lock); | |
1007 | list_for_each_entry(bdev, &all_bdevs, bd_list) { | |
1008 | ret += bdev->bd_inode->i_mapping->nrpages; | |
1009 | } | |
1010 | spin_unlock(&bdev_lock); | |
1011 | return ret; | |
1012 | } | |
1013 | ||
1014 | void bdput(struct block_device *bdev) | |
1015 | { | |
1016 | iput(bdev->bd_inode); | |
1017 | } | |
1018 | ||
1019 | EXPORT_SYMBOL(bdput); | |
1020 | ||
1021 | static struct block_device *bd_acquire(struct inode *inode) | |
1022 | { | |
1023 | struct block_device *bdev; | |
1024 | ||
1025 | spin_lock(&bdev_lock); | |
1026 | bdev = inode->i_bdev; | |
1027 | if (bdev) { | |
1028 | bdgrab(bdev); | |
1029 | spin_unlock(&bdev_lock); | |
1030 | return bdev; | |
1031 | } | |
1032 | spin_unlock(&bdev_lock); | |
1033 | ||
1034 | bdev = bdget(inode->i_rdev); | |
1035 | if (bdev) { | |
1036 | spin_lock(&bdev_lock); | |
1037 | if (!inode->i_bdev) { | |
1038 | /* | |
1039 | * We take an additional reference to bd_inode, | |
1040 | * and it's released in clear_inode() of inode. | |
1041 | * So, we can access it via ->i_mapping always | |
1042 | * without igrab(). | |
1043 | */ | |
1044 | bdgrab(bdev); | |
1045 | inode->i_bdev = bdev; | |
1046 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
1047 | } | |
1048 | spin_unlock(&bdev_lock); | |
1049 | } | |
1050 | return bdev; | |
1051 | } | |
1052 | ||
1053 | /* Call when you free inode */ | |
1054 | ||
1055 | void bd_forget(struct inode *inode) | |
1056 | { | |
1057 | struct block_device *bdev = NULL; | |
1058 | ||
1059 | spin_lock(&bdev_lock); | |
1060 | if (!sb_is_blkdev_sb(inode->i_sb)) | |
1061 | bdev = inode->i_bdev; | |
1062 | inode->i_bdev = NULL; | |
1063 | inode->i_mapping = &inode->i_data; | |
1064 | spin_unlock(&bdev_lock); | |
1065 | ||
1066 | if (bdev) | |
1067 | bdput(bdev); | |
1068 | } | |
1069 | ||
1070 | /** | |
1071 | * bd_may_claim - test whether a block device can be claimed | |
1072 | * @bdev: block device of interest | |
1073 | * @whole: whole block device containing @bdev, may equal @bdev | |
1074 | * @holder: holder trying to claim @bdev | |
1075 | * | |
1076 | * Test whether @bdev can be claimed by @holder. | |
1077 | * | |
1078 | * CONTEXT: | |
1079 | * spin_lock(&bdev_lock). | |
1080 | * | |
1081 | * RETURNS: | |
1082 | * %true if @bdev can be claimed, %false otherwise. | |
1083 | */ | |
1084 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, | |
1085 | void *holder) | |
1086 | { | |
1087 | if (bdev->bd_holder == holder) | |
1088 | return true; /* already a holder */ | |
1089 | else if (bdev->bd_holder != NULL) | |
1090 | return false; /* held by someone else */ | |
1091 | else if (whole == bdev) | |
1092 | return true; /* is a whole device which isn't held */ | |
1093 | ||
1094 | else if (whole->bd_holder == bd_may_claim) | |
1095 | return true; /* is a partition of a device that is being partitioned */ | |
1096 | else if (whole->bd_holder != NULL) | |
1097 | return false; /* is a partition of a held device */ | |
1098 | else | |
1099 | return true; /* is a partition of an un-held device */ | |
1100 | } | |
1101 | ||
1102 | /** | |
1103 | * bd_prepare_to_claim - prepare to claim a block device | |
1104 | * @bdev: block device of interest | |
1105 | * @whole: the whole device containing @bdev, may equal @bdev | |
1106 | * @holder: holder trying to claim @bdev | |
1107 | * | |
1108 | * Prepare to claim @bdev. This function fails if @bdev is already | |
1109 | * claimed by another holder and waits if another claiming is in | |
1110 | * progress. This function doesn't actually claim. On successful | |
1111 | * return, the caller has ownership of bd_claiming and bd_holder[s]. | |
1112 | * | |
1113 | * CONTEXT: | |
1114 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab | |
1115 | * it multiple times. | |
1116 | * | |
1117 | * RETURNS: | |
1118 | * 0 if @bdev can be claimed, -EBUSY otherwise. | |
1119 | */ | |
1120 | static int bd_prepare_to_claim(struct block_device *bdev, | |
1121 | struct block_device *whole, void *holder) | |
1122 | { | |
1123 | retry: | |
1124 | /* if someone else claimed, fail */ | |
1125 | if (!bd_may_claim(bdev, whole, holder)) | |
1126 | return -EBUSY; | |
1127 | ||
1128 | /* if claiming is already in progress, wait for it to finish */ | |
1129 | if (whole->bd_claiming) { | |
1130 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); | |
1131 | DEFINE_WAIT(wait); | |
1132 | ||
1133 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
1134 | spin_unlock(&bdev_lock); | |
1135 | schedule(); | |
1136 | finish_wait(wq, &wait); | |
1137 | spin_lock(&bdev_lock); | |
1138 | goto retry; | |
1139 | } | |
1140 | ||
1141 | /* yay, all mine */ | |
1142 | return 0; | |
1143 | } | |
1144 | ||
1145 | /** | |
1146 | * bd_start_claiming - start claiming a block device | |
1147 | * @bdev: block device of interest | |
1148 | * @holder: holder trying to claim @bdev | |
1149 | * | |
1150 | * @bdev is about to be opened exclusively. Check @bdev can be opened | |
1151 | * exclusively and mark that an exclusive open is in progress. Each | |
1152 | * successful call to this function must be matched with a call to | |
1153 | * either bd_finish_claiming() or bd_abort_claiming() (which do not | |
1154 | * fail). | |
1155 | * | |
1156 | * This function is used to gain exclusive access to the block device | |
1157 | * without actually causing other exclusive open attempts to fail. It | |
1158 | * should be used when the open sequence itself requires exclusive | |
1159 | * access but may subsequently fail. | |
1160 | * | |
1161 | * CONTEXT: | |
1162 | * Might sleep. | |
1163 | * | |
1164 | * RETURNS: | |
1165 | * Pointer to the block device containing @bdev on success, ERR_PTR() | |
1166 | * value on failure. | |
1167 | */ | |
1168 | static struct block_device *bd_start_claiming(struct block_device *bdev, | |
1169 | void *holder) | |
1170 | { | |
1171 | struct gendisk *disk; | |
1172 | struct block_device *whole; | |
1173 | int partno, err; | |
1174 | ||
1175 | might_sleep(); | |
1176 | ||
1177 | /* | |
1178 | * @bdev might not have been initialized properly yet, look up | |
1179 | * and grab the outer block device the hard way. | |
1180 | */ | |
1181 | disk = get_gendisk(bdev->bd_dev, &partno); | |
1182 | if (!disk) | |
1183 | return ERR_PTR(-ENXIO); | |
1184 | ||
1185 | /* | |
1186 | * Normally, @bdev should equal what's returned from bdget_disk() | |
1187 | * if partno is 0; however, some drivers (floppy) use multiple | |
1188 | * bdev's for the same physical device and @bdev may be one of the | |
1189 | * aliases. Keep @bdev if partno is 0. This means claimer | |
1190 | * tracking is broken for those devices but it has always been that | |
1191 | * way. | |
1192 | */ | |
1193 | if (partno) | |
1194 | whole = bdget_disk(disk, 0); | |
1195 | else | |
1196 | whole = bdgrab(bdev); | |
1197 | ||
1198 | module_put(disk->fops->owner); | |
1199 | put_disk(disk); | |
1200 | if (!whole) | |
1201 | return ERR_PTR(-ENOMEM); | |
1202 | ||
1203 | /* prepare to claim, if successful, mark claiming in progress */ | |
1204 | spin_lock(&bdev_lock); | |
1205 | ||
1206 | err = bd_prepare_to_claim(bdev, whole, holder); | |
1207 | if (err == 0) { | |
1208 | whole->bd_claiming = holder; | |
1209 | spin_unlock(&bdev_lock); | |
1210 | return whole; | |
1211 | } else { | |
1212 | spin_unlock(&bdev_lock); | |
1213 | bdput(whole); | |
1214 | return ERR_PTR(err); | |
1215 | } | |
1216 | } | |
1217 | ||
1218 | #ifdef CONFIG_SYSFS | |
1219 | struct bd_holder_disk { | |
1220 | struct list_head list; | |
1221 | struct gendisk *disk; | |
1222 | int refcnt; | |
1223 | }; | |
1224 | ||
1225 | static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, | |
1226 | struct gendisk *disk) | |
1227 | { | |
1228 | struct bd_holder_disk *holder; | |
1229 | ||
1230 | list_for_each_entry(holder, &bdev->bd_holder_disks, list) | |
1231 | if (holder->disk == disk) | |
1232 | return holder; | |
1233 | return NULL; | |
1234 | } | |
1235 | ||
1236 | static int add_symlink(struct kobject *from, struct kobject *to) | |
1237 | { | |
1238 | return sysfs_create_link(from, to, kobject_name(to)); | |
1239 | } | |
1240 | ||
1241 | static void del_symlink(struct kobject *from, struct kobject *to) | |
1242 | { | |
1243 | sysfs_remove_link(from, kobject_name(to)); | |
1244 | } | |
1245 | ||
1246 | /** | |
1247 | * bd_link_disk_holder - create symlinks between holding disk and slave bdev | |
1248 | * @bdev: the claimed slave bdev | |
1249 | * @disk: the holding disk | |
1250 | * | |
1251 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
1252 | * | |
1253 | * This functions creates the following sysfs symlinks. | |
1254 | * | |
1255 | * - from "slaves" directory of the holder @disk to the claimed @bdev | |
1256 | * - from "holders" directory of the @bdev to the holder @disk | |
1257 | * | |
1258 | * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is | |
1259 | * passed to bd_link_disk_holder(), then: | |
1260 | * | |
1261 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda | |
1262 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
1263 | * | |
1264 | * The caller must have claimed @bdev before calling this function and | |
1265 | * ensure that both @bdev and @disk are valid during the creation and | |
1266 | * lifetime of these symlinks. | |
1267 | * | |
1268 | * CONTEXT: | |
1269 | * Might sleep. | |
1270 | * | |
1271 | * RETURNS: | |
1272 | * 0 on success, -errno on failure. | |
1273 | */ | |
1274 | int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
1275 | { | |
1276 | struct bd_holder_disk *holder; | |
1277 | int ret = 0; | |
1278 | ||
1279 | mutex_lock(&bdev->bd_mutex); | |
1280 | ||
1281 | WARN_ON_ONCE(!bdev->bd_holder); | |
1282 | ||
1283 | /* FIXME: remove the following once add_disk() handles errors */ | |
1284 | if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) | |
1285 | goto out_unlock; | |
1286 | ||
1287 | holder = bd_find_holder_disk(bdev, disk); | |
1288 | if (holder) { | |
1289 | holder->refcnt++; | |
1290 | goto out_unlock; | |
1291 | } | |
1292 | ||
1293 | holder = kzalloc(sizeof(*holder), GFP_KERNEL); | |
1294 | if (!holder) { | |
1295 | ret = -ENOMEM; | |
1296 | goto out_unlock; | |
1297 | } | |
1298 | ||
1299 | INIT_LIST_HEAD(&holder->list); | |
1300 | holder->disk = disk; | |
1301 | holder->refcnt = 1; | |
1302 | ||
1303 | ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1304 | if (ret) | |
1305 | goto out_free; | |
1306 | ||
1307 | ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); | |
1308 | if (ret) | |
1309 | goto out_del; | |
1310 | /* | |
1311 | * bdev could be deleted beneath us which would implicitly destroy | |
1312 | * the holder directory. Hold on to it. | |
1313 | */ | |
1314 | kobject_get(bdev->bd_part->holder_dir); | |
1315 | ||
1316 | list_add(&holder->list, &bdev->bd_holder_disks); | |
1317 | goto out_unlock; | |
1318 | ||
1319 | out_del: | |
1320 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1321 | out_free: | |
1322 | kfree(holder); | |
1323 | out_unlock: | |
1324 | mutex_unlock(&bdev->bd_mutex); | |
1325 | return ret; | |
1326 | } | |
1327 | EXPORT_SYMBOL_GPL(bd_link_disk_holder); | |
1328 | ||
1329 | /** | |
1330 | * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() | |
1331 | * @bdev: the calimed slave bdev | |
1332 | * @disk: the holding disk | |
1333 | * | |
1334 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
1335 | * | |
1336 | * CONTEXT: | |
1337 | * Might sleep. | |
1338 | */ | |
1339 | void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
1340 | { | |
1341 | struct bd_holder_disk *holder; | |
1342 | ||
1343 | mutex_lock(&bdev->bd_mutex); | |
1344 | ||
1345 | holder = bd_find_holder_disk(bdev, disk); | |
1346 | ||
1347 | if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { | |
1348 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1349 | del_symlink(bdev->bd_part->holder_dir, | |
1350 | &disk_to_dev(disk)->kobj); | |
1351 | kobject_put(bdev->bd_part->holder_dir); | |
1352 | list_del_init(&holder->list); | |
1353 | kfree(holder); | |
1354 | } | |
1355 | ||
1356 | mutex_unlock(&bdev->bd_mutex); | |
1357 | } | |
1358 | EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); | |
1359 | #endif | |
1360 | ||
1361 | /** | |
1362 | * flush_disk - invalidates all buffer-cache entries on a disk | |
1363 | * | |
1364 | * @bdev: struct block device to be flushed | |
1365 | * @kill_dirty: flag to guide handling of dirty inodes | |
1366 | * | |
1367 | * Invalidates all buffer-cache entries on a disk. It should be called | |
1368 | * when a disk has been changed -- either by a media change or online | |
1369 | * resize. | |
1370 | */ | |
1371 | static void flush_disk(struct block_device *bdev, bool kill_dirty) | |
1372 | { | |
1373 | if (__invalidate_device(bdev, kill_dirty)) { | |
1374 | printk(KERN_WARNING "VFS: busy inodes on changed media or " | |
1375 | "resized disk %s\n", | |
1376 | bdev->bd_disk ? bdev->bd_disk->disk_name : ""); | |
1377 | } | |
1378 | ||
1379 | if (!bdev->bd_disk) | |
1380 | return; | |
1381 | if (disk_part_scan_enabled(bdev->bd_disk)) | |
1382 | bdev->bd_invalidated = 1; | |
1383 | } | |
1384 | ||
1385 | /** | |
1386 | * check_disk_size_change - checks for disk size change and adjusts bdev size. | |
1387 | * @disk: struct gendisk to check | |
1388 | * @bdev: struct bdev to adjust. | |
1389 | * | |
1390 | * This routine checks to see if the bdev size does not match the disk size | |
1391 | * and adjusts it if it differs. | |
1392 | */ | |
1393 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) | |
1394 | { | |
1395 | loff_t disk_size, bdev_size; | |
1396 | ||
1397 | disk_size = (loff_t)get_capacity(disk) << 9; | |
1398 | bdev_size = i_size_read(bdev->bd_inode); | |
1399 | if (disk_size != bdev_size) { | |
1400 | printk(KERN_INFO | |
1401 | "%s: detected capacity change from %lld to %lld\n", | |
1402 | disk->disk_name, bdev_size, disk_size); | |
1403 | i_size_write(bdev->bd_inode, disk_size); | |
1404 | flush_disk(bdev, false); | |
1405 | } | |
1406 | } | |
1407 | EXPORT_SYMBOL(check_disk_size_change); | |
1408 | ||
1409 | /** | |
1410 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back | |
1411 | * @disk: struct gendisk to be revalidated | |
1412 | * | |
1413 | * This routine is a wrapper for lower-level driver's revalidate_disk | |
1414 | * call-backs. It is used to do common pre and post operations needed | |
1415 | * for all revalidate_disk operations. | |
1416 | */ | |
1417 | int revalidate_disk(struct gendisk *disk) | |
1418 | { | |
1419 | struct block_device *bdev; | |
1420 | int ret = 0; | |
1421 | ||
1422 | if (disk->fops->revalidate_disk) | |
1423 | ret = disk->fops->revalidate_disk(disk); | |
1424 | bdev = bdget_disk(disk, 0); | |
1425 | if (!bdev) | |
1426 | return ret; | |
1427 | ||
1428 | mutex_lock(&bdev->bd_mutex); | |
1429 | check_disk_size_change(disk, bdev); | |
1430 | bdev->bd_invalidated = 0; | |
1431 | mutex_unlock(&bdev->bd_mutex); | |
1432 | bdput(bdev); | |
1433 | return ret; | |
1434 | } | |
1435 | EXPORT_SYMBOL(revalidate_disk); | |
1436 | ||
1437 | /* | |
1438 | * This routine checks whether a removable media has been changed, | |
1439 | * and invalidates all buffer-cache-entries in that case. This | |
1440 | * is a relatively slow routine, so we have to try to minimize using | |
1441 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
1442 | * is the best way of combining speed and utility, I think. | |
1443 | * People changing diskettes in the middle of an operation deserve | |
1444 | * to lose :-) | |
1445 | */ | |
1446 | int check_disk_change(struct block_device *bdev) | |
1447 | { | |
1448 | struct gendisk *disk = bdev->bd_disk; | |
1449 | const struct block_device_operations *bdops = disk->fops; | |
1450 | unsigned int events; | |
1451 | ||
1452 | events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | | |
1453 | DISK_EVENT_EJECT_REQUEST); | |
1454 | if (!(events & DISK_EVENT_MEDIA_CHANGE)) | |
1455 | return 0; | |
1456 | ||
1457 | flush_disk(bdev, true); | |
1458 | if (bdops->revalidate_disk) | |
1459 | bdops->revalidate_disk(bdev->bd_disk); | |
1460 | return 1; | |
1461 | } | |
1462 | ||
1463 | EXPORT_SYMBOL(check_disk_change); | |
1464 | ||
1465 | void bd_set_size(struct block_device *bdev, loff_t size) | |
1466 | { | |
1467 | unsigned bsize = bdev_logical_block_size(bdev); | |
1468 | ||
1469 | inode_lock(bdev->bd_inode); | |
1470 | i_size_write(bdev->bd_inode, size); | |
1471 | inode_unlock(bdev->bd_inode); | |
1472 | while (bsize < PAGE_SIZE) { | |
1473 | if (size & bsize) | |
1474 | break; | |
1475 | bsize <<= 1; | |
1476 | } | |
1477 | bdev->bd_block_size = bsize; | |
1478 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
1479 | } | |
1480 | EXPORT_SYMBOL(bd_set_size); | |
1481 | ||
1482 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); | |
1483 | ||
1484 | /* | |
1485 | * bd_mutex locking: | |
1486 | * | |
1487 | * mutex_lock(part->bd_mutex) | |
1488 | * mutex_lock_nested(whole->bd_mutex, 1) | |
1489 | */ | |
1490 | ||
1491 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) | |
1492 | { | |
1493 | struct gendisk *disk; | |
1494 | struct module *owner; | |
1495 | int ret; | |
1496 | int partno; | |
1497 | int perm = 0; | |
1498 | ||
1499 | if (mode & FMODE_READ) | |
1500 | perm |= MAY_READ; | |
1501 | if (mode & FMODE_WRITE) | |
1502 | perm |= MAY_WRITE; | |
1503 | /* | |
1504 | * hooks: /n/, see "layering violations". | |
1505 | */ | |
1506 | if (!for_part) { | |
1507 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); | |
1508 | if (ret != 0) { | |
1509 | bdput(bdev); | |
1510 | return ret; | |
1511 | } | |
1512 | } | |
1513 | ||
1514 | restart: | |
1515 | ||
1516 | ret = -ENXIO; | |
1517 | disk = get_gendisk(bdev->bd_dev, &partno); | |
1518 | if (!disk) | |
1519 | goto out; | |
1520 | owner = disk->fops->owner; | |
1521 | ||
1522 | disk_block_events(disk); | |
1523 | mutex_lock_nested(&bdev->bd_mutex, for_part); | |
1524 | if (!bdev->bd_openers) { | |
1525 | bdev->bd_disk = disk; | |
1526 | bdev->bd_queue = disk->queue; | |
1527 | bdev->bd_contains = bdev; | |
1528 | ||
1529 | if (!partno) { | |
1530 | ret = -ENXIO; | |
1531 | bdev->bd_part = disk_get_part(disk, partno); | |
1532 | if (!bdev->bd_part) | |
1533 | goto out_clear; | |
1534 | ||
1535 | ret = 0; | |
1536 | if (disk->fops->open) { | |
1537 | ret = disk->fops->open(bdev, mode); | |
1538 | if (ret == -ERESTARTSYS) { | |
1539 | /* Lost a race with 'disk' being | |
1540 | * deleted, try again. | |
1541 | * See md.c | |
1542 | */ | |
1543 | disk_put_part(bdev->bd_part); | |
1544 | bdev->bd_part = NULL; | |
1545 | bdev->bd_disk = NULL; | |
1546 | bdev->bd_queue = NULL; | |
1547 | mutex_unlock(&bdev->bd_mutex); | |
1548 | disk_unblock_events(disk); | |
1549 | put_disk(disk); | |
1550 | module_put(owner); | |
1551 | goto restart; | |
1552 | } | |
1553 | } | |
1554 | ||
1555 | if (!ret) | |
1556 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); | |
1557 | ||
1558 | /* | |
1559 | * If the device is invalidated, rescan partition | |
1560 | * if open succeeded or failed with -ENOMEDIUM. | |
1561 | * The latter is necessary to prevent ghost | |
1562 | * partitions on a removed medium. | |
1563 | */ | |
1564 | if (bdev->bd_invalidated) { | |
1565 | if (!ret) | |
1566 | rescan_partitions(disk, bdev); | |
1567 | else if (ret == -ENOMEDIUM) | |
1568 | invalidate_partitions(disk, bdev); | |
1569 | } | |
1570 | ||
1571 | if (ret) | |
1572 | goto out_clear; | |
1573 | } else { | |
1574 | struct block_device *whole; | |
1575 | whole = bdget_disk(disk, 0); | |
1576 | ret = -ENOMEM; | |
1577 | if (!whole) | |
1578 | goto out_clear; | |
1579 | BUG_ON(for_part); | |
1580 | ret = __blkdev_get(whole, mode, 1); | |
1581 | if (ret) | |
1582 | goto out_clear; | |
1583 | bdev->bd_contains = whole; | |
1584 | bdev->bd_part = disk_get_part(disk, partno); | |
1585 | if (!(disk->flags & GENHD_FL_UP) || | |
1586 | !bdev->bd_part || !bdev->bd_part->nr_sects) { | |
1587 | ret = -ENXIO; | |
1588 | goto out_clear; | |
1589 | } | |
1590 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); | |
1591 | } | |
1592 | } else { | |
1593 | if (bdev->bd_contains == bdev) { | |
1594 | ret = 0; | |
1595 | if (bdev->bd_disk->fops->open) | |
1596 | ret = bdev->bd_disk->fops->open(bdev, mode); | |
1597 | /* the same as first opener case, read comment there */ | |
1598 | if (bdev->bd_invalidated) { | |
1599 | if (!ret) | |
1600 | rescan_partitions(bdev->bd_disk, bdev); | |
1601 | else if (ret == -ENOMEDIUM) | |
1602 | invalidate_partitions(bdev->bd_disk, bdev); | |
1603 | } | |
1604 | if (ret) | |
1605 | goto out_unlock_bdev; | |
1606 | } | |
1607 | /* only one opener holds refs to the module and disk */ | |
1608 | put_disk(disk); | |
1609 | module_put(owner); | |
1610 | } | |
1611 | bdev->bd_openers++; | |
1612 | if (for_part) | |
1613 | bdev->bd_part_count++; | |
1614 | mutex_unlock(&bdev->bd_mutex); | |
1615 | disk_unblock_events(disk); | |
1616 | return 0; | |
1617 | ||
1618 | out_clear: | |
1619 | disk_put_part(bdev->bd_part); | |
1620 | bdev->bd_disk = NULL; | |
1621 | bdev->bd_part = NULL; | |
1622 | bdev->bd_queue = NULL; | |
1623 | if (bdev != bdev->bd_contains) | |
1624 | __blkdev_put(bdev->bd_contains, mode, 1); | |
1625 | bdev->bd_contains = NULL; | |
1626 | out_unlock_bdev: | |
1627 | mutex_unlock(&bdev->bd_mutex); | |
1628 | disk_unblock_events(disk); | |
1629 | put_disk(disk); | |
1630 | module_put(owner); | |
1631 | out: | |
1632 | bdput(bdev); | |
1633 | ||
1634 | return ret; | |
1635 | } | |
1636 | ||
1637 | /** | |
1638 | * blkdev_get - open a block device | |
1639 | * @bdev: block_device to open | |
1640 | * @mode: FMODE_* mask | |
1641 | * @holder: exclusive holder identifier | |
1642 | * | |
1643 | * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is | |
1644 | * open with exclusive access. Specifying %FMODE_EXCL with %NULL | |
1645 | * @holder is invalid. Exclusive opens may nest for the same @holder. | |
1646 | * | |
1647 | * On success, the reference count of @bdev is unchanged. On failure, | |
1648 | * @bdev is put. | |
1649 | * | |
1650 | * CONTEXT: | |
1651 | * Might sleep. | |
1652 | * | |
1653 | * RETURNS: | |
1654 | * 0 on success, -errno on failure. | |
1655 | */ | |
1656 | int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) | |
1657 | { | |
1658 | struct block_device *whole = NULL; | |
1659 | int res; | |
1660 | ||
1661 | WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); | |
1662 | ||
1663 | if ((mode & FMODE_EXCL) && holder) { | |
1664 | whole = bd_start_claiming(bdev, holder); | |
1665 | if (IS_ERR(whole)) { | |
1666 | bdput(bdev); | |
1667 | return PTR_ERR(whole); | |
1668 | } | |
1669 | } | |
1670 | ||
1671 | res = __blkdev_get(bdev, mode, 0); | |
1672 | ||
1673 | if (whole) { | |
1674 | struct gendisk *disk = whole->bd_disk; | |
1675 | ||
1676 | /* finish claiming */ | |
1677 | mutex_lock(&bdev->bd_mutex); | |
1678 | spin_lock(&bdev_lock); | |
1679 | ||
1680 | if (!res) { | |
1681 | BUG_ON(!bd_may_claim(bdev, whole, holder)); | |
1682 | /* | |
1683 | * Note that for a whole device bd_holders | |
1684 | * will be incremented twice, and bd_holder | |
1685 | * will be set to bd_may_claim before being | |
1686 | * set to holder | |
1687 | */ | |
1688 | whole->bd_holders++; | |
1689 | whole->bd_holder = bd_may_claim; | |
1690 | bdev->bd_holders++; | |
1691 | bdev->bd_holder = holder; | |
1692 | } | |
1693 | ||
1694 | /* tell others that we're done */ | |
1695 | BUG_ON(whole->bd_claiming != holder); | |
1696 | whole->bd_claiming = NULL; | |
1697 | wake_up_bit(&whole->bd_claiming, 0); | |
1698 | ||
1699 | spin_unlock(&bdev_lock); | |
1700 | ||
1701 | /* | |
1702 | * Block event polling for write claims if requested. Any | |
1703 | * write holder makes the write_holder state stick until | |
1704 | * all are released. This is good enough and tracking | |
1705 | * individual writeable reference is too fragile given the | |
1706 | * way @mode is used in blkdev_get/put(). | |
1707 | */ | |
1708 | if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && | |
1709 | (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { | |
1710 | bdev->bd_write_holder = true; | |
1711 | disk_block_events(disk); | |
1712 | } | |
1713 | ||
1714 | mutex_unlock(&bdev->bd_mutex); | |
1715 | bdput(whole); | |
1716 | } | |
1717 | ||
1718 | return res; | |
1719 | } | |
1720 | EXPORT_SYMBOL(blkdev_get); | |
1721 | ||
1722 | /** | |
1723 | * blkdev_get_by_path - open a block device by name | |
1724 | * @path: path to the block device to open | |
1725 | * @mode: FMODE_* mask | |
1726 | * @holder: exclusive holder identifier | |
1727 | * | |
1728 | * Open the blockdevice described by the device file at @path. @mode | |
1729 | * and @holder are identical to blkdev_get(). | |
1730 | * | |
1731 | * On success, the returned block_device has reference count of one. | |
1732 | * | |
1733 | * CONTEXT: | |
1734 | * Might sleep. | |
1735 | * | |
1736 | * RETURNS: | |
1737 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1738 | */ | |
1739 | struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, | |
1740 | void *holder) | |
1741 | { | |
1742 | struct block_device *bdev; | |
1743 | int perm = 0; | |
1744 | int err; | |
1745 | ||
1746 | if (mode & FMODE_READ) | |
1747 | perm |= MAY_READ; | |
1748 | if (mode & FMODE_WRITE) | |
1749 | perm |= MAY_WRITE; | |
1750 | bdev = lookup_bdev(path, perm); | |
1751 | if (IS_ERR(bdev)) | |
1752 | return bdev; | |
1753 | ||
1754 | err = blkdev_get(bdev, mode, holder); | |
1755 | if (err) | |
1756 | return ERR_PTR(err); | |
1757 | ||
1758 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { | |
1759 | blkdev_put(bdev, mode); | |
1760 | return ERR_PTR(-EACCES); | |
1761 | } | |
1762 | ||
1763 | return bdev; | |
1764 | } | |
1765 | EXPORT_SYMBOL(blkdev_get_by_path); | |
1766 | ||
1767 | /** | |
1768 | * blkdev_get_by_dev - open a block device by device number | |
1769 | * @dev: device number of block device to open | |
1770 | * @mode: FMODE_* mask | |
1771 | * @holder: exclusive holder identifier | |
1772 | * | |
1773 | * Open the blockdevice described by device number @dev. @mode and | |
1774 | * @holder are identical to blkdev_get(). | |
1775 | * | |
1776 | * Use it ONLY if you really do not have anything better - i.e. when | |
1777 | * you are behind a truly sucky interface and all you are given is a | |
1778 | * device number. _Never_ to be used for internal purposes. If you | |
1779 | * ever need it - reconsider your API. | |
1780 | * | |
1781 | * On success, the returned block_device has reference count of one. | |
1782 | * | |
1783 | * CONTEXT: | |
1784 | * Might sleep. | |
1785 | * | |
1786 | * RETURNS: | |
1787 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1788 | */ | |
1789 | struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) | |
1790 | { | |
1791 | struct block_device *bdev; | |
1792 | int err; | |
1793 | ||
1794 | bdev = bdget(dev); | |
1795 | if (!bdev) | |
1796 | return ERR_PTR(-ENOMEM); | |
1797 | ||
1798 | err = blkdev_get(bdev, mode, holder); | |
1799 | if (err) | |
1800 | return ERR_PTR(err); | |
1801 | ||
1802 | return bdev; | |
1803 | } | |
1804 | EXPORT_SYMBOL(blkdev_get_by_dev); | |
1805 | ||
1806 | static int blkdev_open(struct inode * inode, struct file * filp) | |
1807 | { | |
1808 | struct block_device *bdev; | |
1809 | ||
1810 | /* | |
1811 | * Preserve backwards compatibility and allow large file access | |
1812 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
1813 | * binary needs it. We might want to drop this workaround | |
1814 | * during an unstable branch. | |
1815 | */ | |
1816 | filp->f_flags |= O_LARGEFILE; | |
1817 | ||
1818 | if (filp->f_flags & O_NDELAY) | |
1819 | filp->f_mode |= FMODE_NDELAY; | |
1820 | if (filp->f_flags & O_EXCL) | |
1821 | filp->f_mode |= FMODE_EXCL; | |
1822 | if ((filp->f_flags & O_ACCMODE) == 3) | |
1823 | filp->f_mode |= FMODE_WRITE_IOCTL; | |
1824 | ||
1825 | bdev = bd_acquire(inode); | |
1826 | if (bdev == NULL) | |
1827 | return -ENOMEM; | |
1828 | ||
1829 | /* | |
1830 | * A negative i_writecount for bdev->bd_inode means that the bdev | |
1831 | * or one of its paritions is mounted in a user namespace. Deny | |
1832 | * writing for non-root in this case, otherwise an unprivileged | |
1833 | * user can attack the kernel by modifying the backing store of a | |
1834 | * mounted filesystem. | |
1835 | */ | |
1836 | if ((filp->f_mode & FMODE_WRITE) && | |
1837 | !file_ns_capable(filp, &init_user_ns, CAP_SYS_ADMIN) && | |
1838 | !atomic_inc_unless_negative(&bdev->bd_inode->i_writecount)) { | |
1839 | bdput(bdev); | |
1840 | return -EBUSY; | |
1841 | } | |
1842 | ||
1843 | filp->f_mapping = bdev->bd_inode->i_mapping; | |
1844 | ||
1845 | return blkdev_get(bdev, filp->f_mode, filp); | |
1846 | } | |
1847 | ||
1848 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) | |
1849 | { | |
1850 | struct gendisk *disk = bdev->bd_disk; | |
1851 | struct block_device *victim = NULL; | |
1852 | ||
1853 | mutex_lock_nested(&bdev->bd_mutex, for_part); | |
1854 | if (for_part) | |
1855 | bdev->bd_part_count--; | |
1856 | ||
1857 | if (!--bdev->bd_openers) { | |
1858 | WARN_ON_ONCE(bdev->bd_holders); | |
1859 | sync_blockdev(bdev); | |
1860 | kill_bdev(bdev); | |
1861 | ||
1862 | bdev_write_inode(bdev); | |
1863 | /* | |
1864 | * Detaching bdev inode from its wb in __destroy_inode() | |
1865 | * is too late: the queue which embeds its bdi (along with | |
1866 | * root wb) can be gone as soon as we put_disk() below. | |
1867 | */ | |
1868 | inode_detach_wb(bdev->bd_inode); | |
1869 | } | |
1870 | if (bdev->bd_contains == bdev) { | |
1871 | if (disk->fops->release) | |
1872 | disk->fops->release(disk, mode); | |
1873 | } | |
1874 | if (!bdev->bd_openers) { | |
1875 | struct module *owner = disk->fops->owner; | |
1876 | ||
1877 | disk_put_part(bdev->bd_part); | |
1878 | bdev->bd_part = NULL; | |
1879 | bdev->bd_disk = NULL; | |
1880 | if (bdev != bdev->bd_contains) | |
1881 | victim = bdev->bd_contains; | |
1882 | bdev->bd_contains = NULL; | |
1883 | ||
1884 | put_disk(disk); | |
1885 | module_put(owner); | |
1886 | } | |
1887 | mutex_unlock(&bdev->bd_mutex); | |
1888 | bdput(bdev); | |
1889 | if (victim) | |
1890 | __blkdev_put(victim, mode, 1); | |
1891 | } | |
1892 | ||
1893 | void blkdev_put(struct block_device *bdev, fmode_t mode) | |
1894 | { | |
1895 | mutex_lock(&bdev->bd_mutex); | |
1896 | ||
1897 | if (mode & FMODE_EXCL) { | |
1898 | bool bdev_free; | |
1899 | ||
1900 | /* | |
1901 | * Release a claim on the device. The holder fields | |
1902 | * are protected with bdev_lock. bd_mutex is to | |
1903 | * synchronize disk_holder unlinking. | |
1904 | */ | |
1905 | spin_lock(&bdev_lock); | |
1906 | ||
1907 | WARN_ON_ONCE(--bdev->bd_holders < 0); | |
1908 | WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); | |
1909 | ||
1910 | /* bd_contains might point to self, check in a separate step */ | |
1911 | if ((bdev_free = !bdev->bd_holders)) | |
1912 | bdev->bd_holder = NULL; | |
1913 | if (!bdev->bd_contains->bd_holders) | |
1914 | bdev->bd_contains->bd_holder = NULL; | |
1915 | ||
1916 | spin_unlock(&bdev_lock); | |
1917 | ||
1918 | /* | |
1919 | * If this was the last claim, remove holder link and | |
1920 | * unblock evpoll if it was a write holder. | |
1921 | */ | |
1922 | if (bdev_free && bdev->bd_write_holder) { | |
1923 | disk_unblock_events(bdev->bd_disk); | |
1924 | bdev->bd_write_holder = false; | |
1925 | } | |
1926 | } | |
1927 | ||
1928 | /* | |
1929 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE | |
1930 | * event. This is to ensure detection of media removal commanded | |
1931 | * from userland - e.g. eject(1). | |
1932 | */ | |
1933 | disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); | |
1934 | ||
1935 | mutex_unlock(&bdev->bd_mutex); | |
1936 | ||
1937 | __blkdev_put(bdev, mode, 0); | |
1938 | } | |
1939 | EXPORT_SYMBOL(blkdev_put); | |
1940 | ||
1941 | static int blkdev_close(struct inode * inode, struct file * filp) | |
1942 | { | |
1943 | struct block_device *bdev = I_BDEV(bdev_file_inode(filp)); | |
1944 | if (filp->f_mode & FMODE_WRITE && | |
1945 | !file_ns_capable(filp, &init_user_ns, CAP_SYS_ADMIN)) | |
1946 | atomic_dec(&bdev->bd_inode->i_writecount); | |
1947 | blkdev_put(bdev, filp->f_mode); | |
1948 | return 0; | |
1949 | } | |
1950 | ||
1951 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) | |
1952 | { | |
1953 | struct block_device *bdev = I_BDEV(bdev_file_inode(file)); | |
1954 | fmode_t mode = file->f_mode; | |
1955 | ||
1956 | /* | |
1957 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have | |
1958 | * to updated it before every ioctl. | |
1959 | */ | |
1960 | if (file->f_flags & O_NDELAY) | |
1961 | mode |= FMODE_NDELAY; | |
1962 | else | |
1963 | mode &= ~FMODE_NDELAY; | |
1964 | ||
1965 | return blkdev_ioctl(bdev, mode, cmd, arg); | |
1966 | } | |
1967 | ||
1968 | /* | |
1969 | * Write data to the block device. Only intended for the block device itself | |
1970 | * and the raw driver which basically is a fake block device. | |
1971 | * | |
1972 | * Does not take i_mutex for the write and thus is not for general purpose | |
1973 | * use. | |
1974 | */ | |
1975 | ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) | |
1976 | { | |
1977 | struct file *file = iocb->ki_filp; | |
1978 | struct inode *bd_inode = bdev_file_inode(file); | |
1979 | loff_t size = i_size_read(bd_inode); | |
1980 | struct blk_plug plug; | |
1981 | ssize_t ret; | |
1982 | ||
1983 | if (bdev_read_only(I_BDEV(bd_inode))) | |
1984 | return -EPERM; | |
1985 | ||
1986 | if (!iov_iter_count(from)) | |
1987 | return 0; | |
1988 | ||
1989 | if (iocb->ki_pos >= size) | |
1990 | return -ENOSPC; | |
1991 | ||
1992 | iov_iter_truncate(from, size - iocb->ki_pos); | |
1993 | ||
1994 | blk_start_plug(&plug); | |
1995 | ret = __generic_file_write_iter(iocb, from); | |
1996 | if (ret > 0) | |
1997 | ret = generic_write_sync(iocb, ret); | |
1998 | blk_finish_plug(&plug); | |
1999 | return ret; | |
2000 | } | |
2001 | EXPORT_SYMBOL_GPL(blkdev_write_iter); | |
2002 | ||
2003 | ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) | |
2004 | { | |
2005 | struct file *file = iocb->ki_filp; | |
2006 | struct inode *bd_inode = bdev_file_inode(file); | |
2007 | loff_t size = i_size_read(bd_inode); | |
2008 | loff_t pos = iocb->ki_pos; | |
2009 | ||
2010 | if (pos >= size) | |
2011 | return 0; | |
2012 | ||
2013 | size -= pos; | |
2014 | iov_iter_truncate(to, size); | |
2015 | return generic_file_read_iter(iocb, to); | |
2016 | } | |
2017 | EXPORT_SYMBOL_GPL(blkdev_read_iter); | |
2018 | ||
2019 | /* | |
2020 | * Try to release a page associated with block device when the system | |
2021 | * is under memory pressure. | |
2022 | */ | |
2023 | static int blkdev_releasepage(struct page *page, gfp_t wait) | |
2024 | { | |
2025 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; | |
2026 | ||
2027 | if (super && super->s_op->bdev_try_to_free_page) | |
2028 | return super->s_op->bdev_try_to_free_page(super, page, wait); | |
2029 | ||
2030 | return try_to_free_buffers(page); | |
2031 | } | |
2032 | ||
2033 | static int blkdev_writepages(struct address_space *mapping, | |
2034 | struct writeback_control *wbc) | |
2035 | { | |
2036 | if (dax_mapping(mapping)) { | |
2037 | struct block_device *bdev = I_BDEV(mapping->host); | |
2038 | ||
2039 | return dax_writeback_mapping_range(mapping, bdev, wbc); | |
2040 | } | |
2041 | return generic_writepages(mapping, wbc); | |
2042 | } | |
2043 | ||
2044 | static const struct address_space_operations def_blk_aops = { | |
2045 | .readpage = blkdev_readpage, | |
2046 | .readpages = blkdev_readpages, | |
2047 | .writepage = blkdev_writepage, | |
2048 | .write_begin = blkdev_write_begin, | |
2049 | .write_end = blkdev_write_end, | |
2050 | .writepages = blkdev_writepages, | |
2051 | .releasepage = blkdev_releasepage, | |
2052 | .direct_IO = blkdev_direct_IO, | |
2053 | .is_dirty_writeback = buffer_check_dirty_writeback, | |
2054 | }; | |
2055 | ||
2056 | #define BLKDEV_FALLOC_FL_SUPPORTED \ | |
2057 | (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ | |
2058 | FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) | |
2059 | ||
2060 | static long blkdev_fallocate(struct file *file, int mode, loff_t start, | |
2061 | loff_t len) | |
2062 | { | |
2063 | struct block_device *bdev = I_BDEV(bdev_file_inode(file)); | |
2064 | struct request_queue *q = bdev_get_queue(bdev); | |
2065 | struct address_space *mapping; | |
2066 | loff_t end = start + len - 1; | |
2067 | loff_t isize; | |
2068 | int error; | |
2069 | ||
2070 | /* Fail if we don't recognize the flags. */ | |
2071 | if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) | |
2072 | return -EOPNOTSUPP; | |
2073 | ||
2074 | /* Don't go off the end of the device. */ | |
2075 | isize = i_size_read(bdev->bd_inode); | |
2076 | if (start >= isize) | |
2077 | return -EINVAL; | |
2078 | if (end >= isize) { | |
2079 | if (mode & FALLOC_FL_KEEP_SIZE) { | |
2080 | len = isize - start; | |
2081 | end = start + len - 1; | |
2082 | } else | |
2083 | return -EINVAL; | |
2084 | } | |
2085 | ||
2086 | /* | |
2087 | * Don't allow IO that isn't aligned to logical block size. | |
2088 | */ | |
2089 | if ((start | len) & (bdev_logical_block_size(bdev) - 1)) | |
2090 | return -EINVAL; | |
2091 | ||
2092 | /* Invalidate the page cache, including dirty pages. */ | |
2093 | mapping = bdev->bd_inode->i_mapping; | |
2094 | truncate_inode_pages_range(mapping, start, end); | |
2095 | ||
2096 | switch (mode) { | |
2097 | case FALLOC_FL_ZERO_RANGE: | |
2098 | case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: | |
2099 | error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, | |
2100 | GFP_KERNEL, false); | |
2101 | break; | |
2102 | case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: | |
2103 | /* Only punch if the device can do zeroing discard. */ | |
2104 | if (!blk_queue_discard(q) || !q->limits.discard_zeroes_data) | |
2105 | return -EOPNOTSUPP; | |
2106 | error = blkdev_issue_discard(bdev, start >> 9, len >> 9, | |
2107 | GFP_KERNEL, 0); | |
2108 | break; | |
2109 | case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: | |
2110 | if (!blk_queue_discard(q)) | |
2111 | return -EOPNOTSUPP; | |
2112 | error = blkdev_issue_discard(bdev, start >> 9, len >> 9, | |
2113 | GFP_KERNEL, 0); | |
2114 | break; | |
2115 | default: | |
2116 | return -EOPNOTSUPP; | |
2117 | } | |
2118 | if (error) | |
2119 | return error; | |
2120 | ||
2121 | /* | |
2122 | * Invalidate again; if someone wandered in and dirtied a page, | |
2123 | * the caller will be given -EBUSY. The third argument is | |
2124 | * inclusive, so the rounding here is safe. | |
2125 | */ | |
2126 | return invalidate_inode_pages2_range(mapping, | |
2127 | start >> PAGE_SHIFT, | |
2128 | end >> PAGE_SHIFT); | |
2129 | } | |
2130 | ||
2131 | const struct file_operations def_blk_fops = { | |
2132 | .open = blkdev_open, | |
2133 | .release = blkdev_close, | |
2134 | .llseek = block_llseek, | |
2135 | .read_iter = blkdev_read_iter, | |
2136 | .write_iter = blkdev_write_iter, | |
2137 | .mmap = generic_file_mmap, | |
2138 | .fsync = blkdev_fsync, | |
2139 | .unlocked_ioctl = block_ioctl, | |
2140 | #ifdef CONFIG_COMPAT | |
2141 | .compat_ioctl = compat_blkdev_ioctl, | |
2142 | #endif | |
2143 | .splice_read = generic_file_splice_read, | |
2144 | .splice_write = iter_file_splice_write, | |
2145 | .fallocate = blkdev_fallocate, | |
2146 | }; | |
2147 | ||
2148 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
2149 | { | |
2150 | int res; | |
2151 | mm_segment_t old_fs = get_fs(); | |
2152 | set_fs(KERNEL_DS); | |
2153 | res = blkdev_ioctl(bdev, 0, cmd, arg); | |
2154 | set_fs(old_fs); | |
2155 | return res; | |
2156 | } | |
2157 | ||
2158 | EXPORT_SYMBOL(ioctl_by_bdev); | |
2159 | ||
2160 | /** | |
2161 | * lookup_bdev - lookup a struct block_device by name | |
2162 | * @pathname: special file representing the block device | |
2163 | * @mask: rights to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
2164 | * | |
2165 | * Get a reference to the blockdevice at @pathname in the current | |
2166 | * namespace if possible and return it. Return ERR_PTR(error) | |
2167 | * otherwise. If @mask is non-zero, check for access rights to the | |
2168 | * inode at @pathname. | |
2169 | */ | |
2170 | struct block_device *lookup_bdev(const char *pathname, int mask) | |
2171 | { | |
2172 | struct block_device *bdev; | |
2173 | struct inode *inode; | |
2174 | struct path path; | |
2175 | int error; | |
2176 | ||
2177 | if (!pathname || !*pathname) | |
2178 | return ERR_PTR(-EINVAL); | |
2179 | ||
2180 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); | |
2181 | if (error) | |
2182 | return ERR_PTR(error); | |
2183 | ||
2184 | inode = d_backing_inode(path.dentry); | |
2185 | if (mask != 0 && !capable(CAP_SYS_ADMIN)) { | |
2186 | error = __inode_permission(inode, mask); | |
2187 | if (error) | |
2188 | goto fail; | |
2189 | } | |
2190 | error = -ENOTBLK; | |
2191 | if (!S_ISBLK(inode->i_mode)) | |
2192 | goto fail; | |
2193 | error = -EACCES; | |
2194 | if (!may_open_dev(&path)) | |
2195 | goto fail; | |
2196 | error = -ENOMEM; | |
2197 | bdev = bd_acquire(inode); | |
2198 | if (!bdev) | |
2199 | goto fail; | |
2200 | out: | |
2201 | path_put(&path); | |
2202 | return bdev; | |
2203 | fail: | |
2204 | bdev = ERR_PTR(error); | |
2205 | goto out; | |
2206 | } | |
2207 | EXPORT_SYMBOL(lookup_bdev); | |
2208 | ||
2209 | int __invalidate_device(struct block_device *bdev, bool kill_dirty) | |
2210 | { | |
2211 | struct super_block *sb = get_super(bdev); | |
2212 | int res = 0; | |
2213 | ||
2214 | if (sb) { | |
2215 | /* | |
2216 | * no need to lock the super, get_super holds the | |
2217 | * read mutex so the filesystem cannot go away | |
2218 | * under us (->put_super runs with the write lock | |
2219 | * hold). | |
2220 | */ | |
2221 | shrink_dcache_sb(sb); | |
2222 | res = invalidate_inodes(sb, kill_dirty); | |
2223 | drop_super(sb); | |
2224 | } | |
2225 | invalidate_bdev(bdev); | |
2226 | return res; | |
2227 | } | |
2228 | EXPORT_SYMBOL(__invalidate_device); | |
2229 | ||
2230 | void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) | |
2231 | { | |
2232 | struct inode *inode, *old_inode = NULL; | |
2233 | ||
2234 | spin_lock(&blockdev_superblock->s_inode_list_lock); | |
2235 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { | |
2236 | struct address_space *mapping = inode->i_mapping; | |
2237 | struct block_device *bdev; | |
2238 | ||
2239 | spin_lock(&inode->i_lock); | |
2240 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || | |
2241 | mapping->nrpages == 0) { | |
2242 | spin_unlock(&inode->i_lock); | |
2243 | continue; | |
2244 | } | |
2245 | __iget(inode); | |
2246 | spin_unlock(&inode->i_lock); | |
2247 | spin_unlock(&blockdev_superblock->s_inode_list_lock); | |
2248 | /* | |
2249 | * We hold a reference to 'inode' so it couldn't have been | |
2250 | * removed from s_inodes list while we dropped the | |
2251 | * s_inode_list_lock We cannot iput the inode now as we can | |
2252 | * be holding the last reference and we cannot iput it under | |
2253 | * s_inode_list_lock. So we keep the reference and iput it | |
2254 | * later. | |
2255 | */ | |
2256 | iput(old_inode); | |
2257 | old_inode = inode; | |
2258 | bdev = I_BDEV(inode); | |
2259 | ||
2260 | mutex_lock(&bdev->bd_mutex); | |
2261 | if (bdev->bd_openers) | |
2262 | func(bdev, arg); | |
2263 | mutex_unlock(&bdev->bd_mutex); | |
2264 | ||
2265 | spin_lock(&blockdev_superblock->s_inode_list_lock); | |
2266 | } | |
2267 | spin_unlock(&blockdev_superblock->s_inode_list_lock); | |
2268 | iput(old_inode); | |
2269 | } |