]>
Commit | Line | Data |
---|---|---|
db074436 DW |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) 2010 Red Hat, Inc. | |
4 | * Copyright (c) 2016-2018 Christoph Hellwig. | |
5 | */ | |
6 | #include <linux/module.h> | |
7 | #include <linux/compiler.h> | |
8 | #include <linux/fs.h> | |
9 | #include <linux/iomap.h> | |
10 | #include <linux/backing-dev.h> | |
11 | #include <linux/uio.h> | |
12 | #include <linux/task_io_accounting_ops.h> | |
60263d58 | 13 | #include "trace.h" |
db074436 DW |
14 | |
15 | #include "../internal.h" | |
16 | ||
17 | /* | |
18 | * Private flags for iomap_dio, must not overlap with the public ones in | |
19 | * iomap.h: | |
20 | */ | |
21 | #define IOMAP_DIO_WRITE_FUA (1 << 28) | |
22 | #define IOMAP_DIO_NEED_SYNC (1 << 29) | |
23 | #define IOMAP_DIO_WRITE (1 << 30) | |
24 | #define IOMAP_DIO_DIRTY (1 << 31) | |
25 | ||
26 | struct iomap_dio { | |
27 | struct kiocb *iocb; | |
838c4f3d | 28 | const struct iomap_dio_ops *dops; |
db074436 DW |
29 | loff_t i_size; |
30 | loff_t size; | |
31 | atomic_t ref; | |
32 | unsigned flags; | |
33 | int error; | |
34 | bool wait_for_completion; | |
35 | ||
36 | union { | |
37 | /* used during submission and for synchronous completion: */ | |
38 | struct { | |
39 | struct iov_iter *iter; | |
40 | struct task_struct *waiter; | |
41 | struct request_queue *last_queue; | |
42 | blk_qc_t cookie; | |
43 | } submit; | |
44 | ||
45 | /* used for aio completion: */ | |
46 | struct { | |
47 | struct work_struct work; | |
48 | } aio; | |
49 | }; | |
50 | }; | |
51 | ||
52 | int iomap_dio_iopoll(struct kiocb *kiocb, bool spin) | |
53 | { | |
54 | struct request_queue *q = READ_ONCE(kiocb->private); | |
55 | ||
56 | if (!q) | |
57 | return 0; | |
58 | return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin); | |
59 | } | |
60 | EXPORT_SYMBOL_GPL(iomap_dio_iopoll); | |
61 | ||
62 | static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, | |
8cecd0ba | 63 | struct bio *bio, loff_t pos) |
db074436 DW |
64 | { |
65 | atomic_inc(&dio->ref); | |
66 | ||
67 | if (dio->iocb->ki_flags & IOCB_HIPRI) | |
68 | bio_set_polled(bio, dio->iocb); | |
69 | ||
70 | dio->submit.last_queue = bdev_get_queue(iomap->bdev); | |
8cecd0ba GR |
71 | if (dio->dops && dio->dops->submit_io) |
72 | dio->submit.cookie = dio->dops->submit_io( | |
73 | file_inode(dio->iocb->ki_filp), | |
74 | iomap, bio, pos); | |
75 | else | |
76 | dio->submit.cookie = submit_bio(bio); | |
db074436 DW |
77 | } |
78 | ||
c3d4ed1a | 79 | ssize_t iomap_dio_complete(struct iomap_dio *dio) |
db074436 | 80 | { |
838c4f3d | 81 | const struct iomap_dio_ops *dops = dio->dops; |
db074436 DW |
82 | struct kiocb *iocb = dio->iocb; |
83 | struct inode *inode = file_inode(iocb->ki_filp); | |
84 | loff_t offset = iocb->ki_pos; | |
838c4f3d | 85 | ssize_t ret = dio->error; |
db074436 | 86 | |
838c4f3d CH |
87 | if (dops && dops->end_io) |
88 | ret = dops->end_io(iocb, dio->size, ret, dio->flags); | |
db074436 DW |
89 | |
90 | if (likely(!ret)) { | |
91 | ret = dio->size; | |
92 | /* check for short read */ | |
93 | if (offset + ret > dio->i_size && | |
94 | !(dio->flags & IOMAP_DIO_WRITE)) | |
95 | ret = dio->i_size - offset; | |
96 | iocb->ki_pos += ret; | |
97 | } | |
98 | ||
99 | /* | |
100 | * Try again to invalidate clean pages which might have been cached by | |
101 | * non-direct readahead, or faulted in by get_user_pages() if the source | |
102 | * of the write was an mmap'ed region of the file we're writing. Either | |
103 | * one is a pretty crazy thing to do, so we don't support it 100%. If | |
104 | * this invalidation fails, tough, the write still worked... | |
105 | * | |
838c4f3d CH |
106 | * And this page cache invalidation has to be after ->end_io(), as some |
107 | * filesystems convert unwritten extents to real allocations in | |
108 | * ->end_io() when necessary, otherwise a racing buffer read would cache | |
db074436 DW |
109 | * zeros from unwritten extents. |
110 | */ | |
c114bbc6 | 111 | if (!dio->error && dio->size && |
db074436 DW |
112 | (dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { |
113 | int err; | |
114 | err = invalidate_inode_pages2_range(inode->i_mapping, | |
115 | offset >> PAGE_SHIFT, | |
116 | (offset + dio->size - 1) >> PAGE_SHIFT); | |
117 | if (err) | |
118 | dio_warn_stale_pagecache(iocb->ki_filp); | |
119 | } | |
120 | ||
1a31182e | 121 | inode_dio_end(file_inode(iocb->ki_filp)); |
db074436 DW |
122 | /* |
123 | * If this is a DSYNC write, make sure we push it to stable storage now | |
124 | * that we've written data. | |
125 | */ | |
126 | if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) | |
127 | ret = generic_write_sync(iocb, ret); | |
128 | ||
db074436 DW |
129 | kfree(dio); |
130 | ||
131 | return ret; | |
132 | } | |
c3d4ed1a | 133 | EXPORT_SYMBOL_GPL(iomap_dio_complete); |
db074436 DW |
134 | |
135 | static void iomap_dio_complete_work(struct work_struct *work) | |
136 | { | |
137 | struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); | |
138 | struct kiocb *iocb = dio->iocb; | |
139 | ||
140 | iocb->ki_complete(iocb, iomap_dio_complete(dio), 0); | |
141 | } | |
142 | ||
143 | /* | |
144 | * Set an error in the dio if none is set yet. We have to use cmpxchg | |
145 | * as the submission context and the completion context(s) can race to | |
146 | * update the error. | |
147 | */ | |
148 | static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret) | |
149 | { | |
150 | cmpxchg(&dio->error, 0, ret); | |
151 | } | |
152 | ||
153 | static void iomap_dio_bio_end_io(struct bio *bio) | |
154 | { | |
155 | struct iomap_dio *dio = bio->bi_private; | |
156 | bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); | |
157 | ||
158 | if (bio->bi_status) | |
159 | iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status)); | |
160 | ||
161 | if (atomic_dec_and_test(&dio->ref)) { | |
162 | if (dio->wait_for_completion) { | |
163 | struct task_struct *waiter = dio->submit.waiter; | |
164 | WRITE_ONCE(dio->submit.waiter, NULL); | |
165 | blk_wake_io_task(waiter); | |
166 | } else if (dio->flags & IOMAP_DIO_WRITE) { | |
167 | struct inode *inode = file_inode(dio->iocb->ki_filp); | |
168 | ||
169 | INIT_WORK(&dio->aio.work, iomap_dio_complete_work); | |
170 | queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work); | |
171 | } else { | |
172 | iomap_dio_complete_work(&dio->aio.work); | |
173 | } | |
174 | } | |
175 | ||
176 | if (should_dirty) { | |
177 | bio_check_pages_dirty(bio); | |
178 | } else { | |
179 | bio_release_pages(bio, false); | |
180 | bio_put(bio); | |
181 | } | |
182 | } | |
183 | ||
184 | static void | |
185 | iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, | |
186 | unsigned len) | |
187 | { | |
188 | struct page *page = ZERO_PAGE(0); | |
189 | int flags = REQ_SYNC | REQ_IDLE; | |
190 | struct bio *bio; | |
191 | ||
192 | bio = bio_alloc(GFP_KERNEL, 1); | |
193 | bio_set_dev(bio, iomap->bdev); | |
194 | bio->bi_iter.bi_sector = iomap_sector(iomap, pos); | |
195 | bio->bi_private = dio; | |
196 | bio->bi_end_io = iomap_dio_bio_end_io; | |
197 | ||
198 | get_page(page); | |
199 | __bio_add_page(bio, page, len, 0); | |
200 | bio_set_op_attrs(bio, REQ_OP_WRITE, flags); | |
8cecd0ba | 201 | iomap_dio_submit_bio(dio, iomap, bio, pos); |
db074436 DW |
202 | } |
203 | ||
204 | static loff_t | |
205 | iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, | |
206 | struct iomap_dio *dio, struct iomap *iomap) | |
207 | { | |
208 | unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev)); | |
209 | unsigned int fs_block_size = i_blocksize(inode), pad; | |
210 | unsigned int align = iov_iter_alignment(dio->submit.iter); | |
db074436 DW |
211 | struct bio *bio; |
212 | bool need_zeroout = false; | |
213 | bool use_fua = false; | |
214 | int nr_pages, ret = 0; | |
215 | size_t copied = 0; | |
f550ee9b | 216 | size_t orig_count; |
db074436 DW |
217 | |
218 | if ((pos | length | align) & ((1 << blkbits) - 1)) | |
219 | return -EINVAL; | |
220 | ||
221 | if (iomap->type == IOMAP_UNWRITTEN) { | |
222 | dio->flags |= IOMAP_DIO_UNWRITTEN; | |
223 | need_zeroout = true; | |
224 | } | |
225 | ||
226 | if (iomap->flags & IOMAP_F_SHARED) | |
227 | dio->flags |= IOMAP_DIO_COW; | |
228 | ||
229 | if (iomap->flags & IOMAP_F_NEW) { | |
230 | need_zeroout = true; | |
231 | } else if (iomap->type == IOMAP_MAPPED) { | |
232 | /* | |
233 | * Use a FUA write if we need datasync semantics, this is a pure | |
234 | * data IO that doesn't require any metadata updates (including | |
235 | * after IO completion such as unwritten extent conversion) and | |
236 | * the underlying device supports FUA. This allows us to avoid | |
237 | * cache flushes on IO completion. | |
238 | */ | |
239 | if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && | |
240 | (dio->flags & IOMAP_DIO_WRITE_FUA) && | |
241 | blk_queue_fua(bdev_get_queue(iomap->bdev))) | |
242 | use_fua = true; | |
243 | } | |
244 | ||
245 | /* | |
f550ee9b JK |
246 | * Save the original count and trim the iter to just the extent we |
247 | * are operating on right now. The iter will be re-expanded once | |
248 | * we are done. | |
db074436 | 249 | */ |
f550ee9b JK |
250 | orig_count = iov_iter_count(dio->submit.iter); |
251 | iov_iter_truncate(dio->submit.iter, length); | |
db074436 | 252 | |
f550ee9b JK |
253 | nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); |
254 | if (nr_pages <= 0) { | |
255 | ret = nr_pages; | |
256 | goto out; | |
257 | } | |
db074436 DW |
258 | |
259 | if (need_zeroout) { | |
260 | /* zero out from the start of the block to the write offset */ | |
261 | pad = pos & (fs_block_size - 1); | |
262 | if (pad) | |
263 | iomap_dio_zero(dio, iomap, pos - pad, pad); | |
264 | } | |
265 | ||
266 | do { | |
267 | size_t n; | |
268 | if (dio->error) { | |
269 | iov_iter_revert(dio->submit.iter, copied); | |
f550ee9b JK |
270 | copied = ret = 0; |
271 | goto out; | |
db074436 DW |
272 | } |
273 | ||
274 | bio = bio_alloc(GFP_KERNEL, nr_pages); | |
275 | bio_set_dev(bio, iomap->bdev); | |
276 | bio->bi_iter.bi_sector = iomap_sector(iomap, pos); | |
277 | bio->bi_write_hint = dio->iocb->ki_hint; | |
278 | bio->bi_ioprio = dio->iocb->ki_ioprio; | |
279 | bio->bi_private = dio; | |
280 | bio->bi_end_io = iomap_dio_bio_end_io; | |
281 | ||
f550ee9b | 282 | ret = bio_iov_iter_get_pages(bio, dio->submit.iter); |
db074436 DW |
283 | if (unlikely(ret)) { |
284 | /* | |
285 | * We have to stop part way through an IO. We must fall | |
286 | * through to the sub-block tail zeroing here, otherwise | |
287 | * this short IO may expose stale data in the tail of | |
288 | * the block we haven't written data to. | |
289 | */ | |
290 | bio_put(bio); | |
291 | goto zero_tail; | |
292 | } | |
293 | ||
294 | n = bio->bi_iter.bi_size; | |
295 | if (dio->flags & IOMAP_DIO_WRITE) { | |
296 | bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; | |
297 | if (use_fua) | |
298 | bio->bi_opf |= REQ_FUA; | |
299 | else | |
300 | dio->flags &= ~IOMAP_DIO_WRITE_FUA; | |
301 | task_io_account_write(n); | |
302 | } else { | |
303 | bio->bi_opf = REQ_OP_READ; | |
304 | if (dio->flags & IOMAP_DIO_DIRTY) | |
305 | bio_set_pages_dirty(bio); | |
306 | } | |
307 | ||
db074436 | 308 | dio->size += n; |
db074436 DW |
309 | copied += n; |
310 | ||
f550ee9b | 311 | nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); |
8cecd0ba GR |
312 | iomap_dio_submit_bio(dio, iomap, bio, pos); |
313 | pos += n; | |
db074436 DW |
314 | } while (nr_pages); |
315 | ||
316 | /* | |
317 | * We need to zeroout the tail of a sub-block write if the extent type | |
318 | * requires zeroing or the write extends beyond EOF. If we don't zero | |
319 | * the block tail in the latter case, we can expose stale data via mmap | |
320 | * reads of the EOF block. | |
321 | */ | |
322 | zero_tail: | |
323 | if (need_zeroout || | |
324 | ((dio->flags & IOMAP_DIO_WRITE) && pos >= i_size_read(inode))) { | |
325 | /* zero out from the end of the write to the end of the block */ | |
326 | pad = pos & (fs_block_size - 1); | |
327 | if (pad) | |
328 | iomap_dio_zero(dio, iomap, pos, fs_block_size - pad); | |
329 | } | |
f550ee9b JK |
330 | out: |
331 | /* Undo iter limitation to current extent */ | |
332 | iov_iter_reexpand(dio->submit.iter, orig_count - copied); | |
e9f930ac JS |
333 | if (copied) |
334 | return copied; | |
335 | return ret; | |
db074436 DW |
336 | } |
337 | ||
338 | static loff_t | |
339 | iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio) | |
340 | { | |
341 | length = iov_iter_zero(length, dio->submit.iter); | |
342 | dio->size += length; | |
343 | return length; | |
344 | } | |
345 | ||
346 | static loff_t | |
347 | iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, | |
348 | struct iomap_dio *dio, struct iomap *iomap) | |
349 | { | |
350 | struct iov_iter *iter = dio->submit.iter; | |
351 | size_t copied; | |
352 | ||
353 | BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data)); | |
354 | ||
355 | if (dio->flags & IOMAP_DIO_WRITE) { | |
356 | loff_t size = inode->i_size; | |
357 | ||
358 | if (pos > size) | |
359 | memset(iomap->inline_data + size, 0, pos - size); | |
360 | copied = copy_from_iter(iomap->inline_data + pos, length, iter); | |
361 | if (copied) { | |
362 | if (pos + copied > size) | |
363 | i_size_write(inode, pos + copied); | |
364 | mark_inode_dirty(inode); | |
365 | } | |
366 | } else { | |
367 | copied = copy_to_iter(iomap->inline_data + pos, length, iter); | |
368 | } | |
369 | dio->size += copied; | |
370 | return copied; | |
371 | } | |
372 | ||
373 | static loff_t | |
374 | iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, | |
c039b997 | 375 | void *data, struct iomap *iomap, struct iomap *srcmap) |
db074436 DW |
376 | { |
377 | struct iomap_dio *dio = data; | |
378 | ||
379 | switch (iomap->type) { | |
380 | case IOMAP_HOLE: | |
381 | if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) | |
382 | return -EIO; | |
383 | return iomap_dio_hole_actor(length, dio); | |
384 | case IOMAP_UNWRITTEN: | |
385 | if (!(dio->flags & IOMAP_DIO_WRITE)) | |
386 | return iomap_dio_hole_actor(length, dio); | |
387 | return iomap_dio_bio_actor(inode, pos, length, dio, iomap); | |
388 | case IOMAP_MAPPED: | |
389 | return iomap_dio_bio_actor(inode, pos, length, dio, iomap); | |
390 | case IOMAP_INLINE: | |
391 | return iomap_dio_inline_actor(inode, pos, length, dio, iomap); | |
a805c111 QC |
392 | case IOMAP_DELALLOC: |
393 | /* | |
394 | * DIO is not serialised against mmap() access at all, and so | |
395 | * if the page_mkwrite occurs between the writeback and the | |
396 | * iomap_apply() call in the DIO path, then it will see the | |
397 | * DELALLOC block that the page-mkwrite allocated. | |
398 | */ | |
399 | pr_warn_ratelimited("Direct I/O collision with buffered writes! File: %pD4 Comm: %.20s\n", | |
400 | dio->iocb->ki_filp, current->comm); | |
401 | return -EIO; | |
db074436 DW |
402 | default: |
403 | WARN_ON_ONCE(1); | |
404 | return -EIO; | |
405 | } | |
406 | } | |
407 | ||
408 | /* | |
409 | * iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO | |
410 | * is being issued as AIO or not. This allows us to optimise pure data writes | |
411 | * to use REQ_FUA rather than requiring generic_write_sync() to issue a | |
412 | * REQ_FLUSH post write. This is slightly tricky because a single request here | |
413 | * can be mapped into multiple disjoint IOs and only a subset of the IOs issued | |
414 | * may be pure data writes. In that case, we still need to do a full data sync | |
415 | * completion. | |
60263d58 CH |
416 | * |
417 | * Returns -ENOTBLK In case of a page invalidation invalidation failure for | |
418 | * writes. The callers needs to fall back to buffered I/O in this case. | |
db074436 | 419 | */ |
c3d4ed1a CH |
420 | struct iomap_dio * |
421 | __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, | |
13ef9544 JK |
422 | const struct iomap_ops *ops, const struct iomap_dio_ops *dops, |
423 | bool wait_for_completion) | |
db074436 DW |
424 | { |
425 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
426 | struct inode *inode = file_inode(iocb->ki_filp); | |
427 | size_t count = iov_iter_count(iter); | |
88cfd30e | 428 | loff_t pos = iocb->ki_pos; |
db074436 | 429 | loff_t end = iocb->ki_pos + count - 1, ret = 0; |
5724be5d | 430 | unsigned int iomap_flags = IOMAP_DIRECT; |
db074436 DW |
431 | struct blk_plug plug; |
432 | struct iomap_dio *dio; | |
433 | ||
db074436 | 434 | if (!count) |
c3d4ed1a | 435 | return NULL; |
db074436 | 436 | |
13ef9544 | 437 | if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion)) |
c3d4ed1a | 438 | return ERR_PTR(-EIO); |
13ef9544 | 439 | |
db074436 DW |
440 | dio = kmalloc(sizeof(*dio), GFP_KERNEL); |
441 | if (!dio) | |
c3d4ed1a | 442 | return ERR_PTR(-ENOMEM); |
db074436 DW |
443 | |
444 | dio->iocb = iocb; | |
445 | atomic_set(&dio->ref, 1); | |
446 | dio->size = 0; | |
447 | dio->i_size = i_size_read(inode); | |
838c4f3d | 448 | dio->dops = dops; |
db074436 DW |
449 | dio->error = 0; |
450 | dio->flags = 0; | |
451 | ||
452 | dio->submit.iter = iter; | |
453 | dio->submit.waiter = current; | |
454 | dio->submit.cookie = BLK_QC_T_NONE; | |
455 | dio->submit.last_queue = NULL; | |
456 | ||
457 | if (iov_iter_rw(iter) == READ) { | |
458 | if (pos >= dio->i_size) | |
459 | goto out_free_dio; | |
460 | ||
a9010042 | 461 | if (iter_is_iovec(iter)) |
db074436 DW |
462 | dio->flags |= IOMAP_DIO_DIRTY; |
463 | } else { | |
5724be5d | 464 | iomap_flags |= IOMAP_WRITE; |
db074436 DW |
465 | dio->flags |= IOMAP_DIO_WRITE; |
466 | ||
467 | /* for data sync or sync, we need sync completion processing */ | |
468 | if (iocb->ki_flags & IOCB_DSYNC) | |
469 | dio->flags |= IOMAP_DIO_NEED_SYNC; | |
470 | ||
471 | /* | |
472 | * For datasync only writes, we optimistically try using FUA for | |
473 | * this IO. Any non-FUA write that occurs will clear this flag, | |
474 | * hence we know before completion whether a cache flush is | |
475 | * necessary. | |
476 | */ | |
477 | if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) | |
478 | dio->flags |= IOMAP_DIO_WRITE_FUA; | |
479 | } | |
480 | ||
481 | if (iocb->ki_flags & IOCB_NOWAIT) { | |
88cfd30e | 482 | if (filemap_range_has_page(mapping, pos, end)) { |
db074436 DW |
483 | ret = -EAGAIN; |
484 | goto out_free_dio; | |
485 | } | |
5724be5d | 486 | iomap_flags |= IOMAP_NOWAIT; |
db074436 DW |
487 | } |
488 | ||
88cfd30e | 489 | ret = filemap_write_and_wait_range(mapping, pos, end); |
db074436 DW |
490 | if (ret) |
491 | goto out_free_dio; | |
492 | ||
54752de9 DC |
493 | if (iov_iter_rw(iter) == WRITE) { |
494 | /* | |
495 | * Try to invalidate cache pages for the range we are writing. | |
60263d58 CH |
496 | * If this invalidation fails, let the caller fall back to |
497 | * buffered I/O. | |
54752de9 DC |
498 | */ |
499 | if (invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, | |
60263d58 CH |
500 | end >> PAGE_SHIFT)) { |
501 | trace_iomap_dio_invalidate_fail(inode, pos, count); | |
502 | ret = -ENOTBLK; | |
503 | goto out_free_dio; | |
504 | } | |
db074436 | 505 | |
54752de9 DC |
506 | if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) { |
507 | ret = sb_init_dio_done_wq(inode->i_sb); | |
508 | if (ret < 0) | |
509 | goto out_free_dio; | |
510 | } | |
db074436 DW |
511 | } |
512 | ||
513 | inode_dio_begin(inode); | |
514 | ||
515 | blk_start_plug(&plug); | |
516 | do { | |
5724be5d | 517 | ret = iomap_apply(inode, pos, count, iomap_flags, ops, dio, |
db074436 DW |
518 | iomap_dio_actor); |
519 | if (ret <= 0) { | |
520 | /* magic error code to fall back to buffered I/O */ | |
521 | if (ret == -ENOTBLK) { | |
522 | wait_for_completion = true; | |
523 | ret = 0; | |
524 | } | |
525 | break; | |
526 | } | |
527 | pos += ret; | |
528 | ||
419e9c38 JK |
529 | if (iov_iter_rw(iter) == READ && pos >= dio->i_size) { |
530 | /* | |
531 | * We only report that we've read data up to i_size. | |
532 | * Revert iter to a state corresponding to that as | |
533 | * some callers (such as splice code) rely on it. | |
534 | */ | |
535 | iov_iter_revert(iter, pos - dio->i_size); | |
db074436 | 536 | break; |
419e9c38 | 537 | } |
db074436 DW |
538 | } while ((count = iov_iter_count(iter)) > 0); |
539 | blk_finish_plug(&plug); | |
540 | ||
541 | if (ret < 0) | |
542 | iomap_dio_set_error(dio, ret); | |
543 | ||
544 | /* | |
545 | * If all the writes we issued were FUA, we don't need to flush the | |
546 | * cache on IO completion. Clear the sync flag for this case. | |
547 | */ | |
548 | if (dio->flags & IOMAP_DIO_WRITE_FUA) | |
549 | dio->flags &= ~IOMAP_DIO_NEED_SYNC; | |
550 | ||
551 | WRITE_ONCE(iocb->ki_cookie, dio->submit.cookie); | |
552 | WRITE_ONCE(iocb->private, dio->submit.last_queue); | |
553 | ||
554 | /* | |
555 | * We are about to drop our additional submission reference, which | |
d9973ce2 | 556 | * might be the last reference to the dio. There are three different |
557 | * ways we can progress here: | |
db074436 DW |
558 | * |
559 | * (a) If this is the last reference we will always complete and free | |
560 | * the dio ourselves. | |
561 | * (b) If this is not the last reference, and we serve an asynchronous | |
562 | * iocb, we must never touch the dio after the decrement, the | |
563 | * I/O completion handler will complete and free it. | |
564 | * (c) If this is not the last reference, but we serve a synchronous | |
565 | * iocb, the I/O completion handler will wake us up on the drop | |
566 | * of the final reference, and we will complete and free it here | |
567 | * after we got woken by the I/O completion handler. | |
568 | */ | |
569 | dio->wait_for_completion = wait_for_completion; | |
570 | if (!atomic_dec_and_test(&dio->ref)) { | |
571 | if (!wait_for_completion) | |
c3d4ed1a | 572 | return ERR_PTR(-EIOCBQUEUED); |
db074436 DW |
573 | |
574 | for (;;) { | |
575 | set_current_state(TASK_UNINTERRUPTIBLE); | |
576 | if (!READ_ONCE(dio->submit.waiter)) | |
577 | break; | |
578 | ||
579 | if (!(iocb->ki_flags & IOCB_HIPRI) || | |
580 | !dio->submit.last_queue || | |
581 | !blk_poll(dio->submit.last_queue, | |
582 | dio->submit.cookie, true)) | |
e6249cdd | 583 | blk_io_schedule(); |
db074436 DW |
584 | } |
585 | __set_current_state(TASK_RUNNING); | |
586 | } | |
587 | ||
c3d4ed1a | 588 | return dio; |
db074436 DW |
589 | |
590 | out_free_dio: | |
591 | kfree(dio); | |
c3d4ed1a CH |
592 | if (ret) |
593 | return ERR_PTR(ret); | |
594 | return NULL; | |
595 | } | |
596 | EXPORT_SYMBOL_GPL(__iomap_dio_rw); | |
597 | ||
598 | ssize_t | |
599 | iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, | |
600 | const struct iomap_ops *ops, const struct iomap_dio_ops *dops, | |
601 | bool wait_for_completion) | |
602 | { | |
603 | struct iomap_dio *dio; | |
604 | ||
605 | dio = __iomap_dio_rw(iocb, iter, ops, dops, wait_for_completion); | |
606 | if (IS_ERR_OR_NULL(dio)) | |
607 | return PTR_ERR_OR_ZERO(dio); | |
608 | return iomap_dio_complete(dio); | |
db074436 DW |
609 | } |
610 | EXPORT_SYMBOL_GPL(iomap_dio_rw); |