1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * This file is part of UBIFS.
4 *
5 * Copyright (C) 2006-2008 Nokia Corporation.
6 *
7 * Authors: Artem Bityutskiy (Битюцкий Артём)
8 * Adrian Hunter
9 */
10
11 /*
12 * This file implements VFS file and inode operations for regular files, device
13 * nodes and symlinks as well as address space operations.
14 *
15 * UBIFS uses 2 page flags: @PG_private and @PG_checked. @PG_private is set if
16 * the page is dirty and is used for optimization purposes - dirty pages are
17 * not budgeted so the flag shows that 'ubifs_write_end()' should not release
18 * the budget for this page. The @PG_checked flag is set if full budgeting is
19 * required for the page e.g., when it corresponds to a file hole or it is
20 * beyond the file size. The budgeting is done in 'ubifs_write_begin()', because
21 * it is OK to fail in this function, and the budget is released in
22 * 'ubifs_write_end()'. So the @PG_private and @PG_checked flags carry
23 * information about how the page was budgeted, to make it possible to release
24 * the budget properly.
25 *
26 * A thing to keep in mind: inode @i_mutex is locked in most VFS operations we
27 * implement. However, this is not true for 'ubifs_writepage()', which may be
28 * called with @i_mutex unlocked. For example, when flusher thread is doing
29 * background write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex.
30 * At "normal" work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g.
31 * in the "sys_write -> alloc_pages -> direct reclaim path". So, in
32 * 'ubifs_writepage()' we are only guaranteed that the page is locked.
33 *
34 * Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the
35 * read-ahead path does not lock it ("sys_read -> generic_file_aio_read ->
36 * ondemand_readahead -> readpage"). In case of readahead, @I_SYNC flag is not
37 * set as well. However, UBIFS disables readahead.
38 */
39
40 #include "ubifs.h"
41 #include <linux/mount.h>
42 #include <linux/slab.h>
43 #include <linux/migrate.h>
44
45 static int read_block(struct inode *inode, void *addr, unsigned int block,
46 struct ubifs_data_node *dn)
47 {
48 struct ubifs_info *c = inode->i_sb->s_fs_info;
49 int err, len, out_len;
50 union ubifs_key key;
51 unsigned int dlen;
52
53 data_key_init(c, &key, inode->i_ino, block);
54 err = ubifs_tnc_lookup(c, &key, dn);
55 if (err) {
56 if (err == -ENOENT)
57 /* Not found, so it must be a hole */
58 memset(addr, 0, UBIFS_BLOCK_SIZE);
59 return err;
60 }
61
62 ubifs_assert(c, le64_to_cpu(dn->ch.sqnum) >
63 ubifs_inode(inode)->creat_sqnum);
64 len = le32_to_cpu(dn->size);
65 if (len <= 0 || len > UBIFS_BLOCK_SIZE)
66 goto dump;
67
68 dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
69
70 if (ubifs_crypt_is_encrypted(inode)) {
71 err = ubifs_decrypt(inode, dn, &dlen, block);
72 if (err)
73 goto dump;
74 }
75
76 out_len = UBIFS_BLOCK_SIZE;
77 err = ubifs_decompress(c, &dn->data, dlen, addr, &out_len,
78 le16_to_cpu(dn->compr_type));
79 if (err || len != out_len)
80 goto dump;
81
82 /*
83 * Data length can be less than a full block, even for blocks that are
84 * not the last in the file (e.g., as a result of making a hole and
85 * appending data). Ensure that the remainder is zeroed out.
86 */
87 if (len < UBIFS_BLOCK_SIZE)
88 memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
89
90 return 0;
91
92 dump:
93 ubifs_err(c, "bad data node (block %u, inode %lu)",
94 block, inode->i_ino);
95 ubifs_dump_node(c, dn);
96 return -EINVAL;
97 }
98
99 static int do_readpage(struct page *page)
100 {
101 void *addr;
102 int err = 0, i;
103 unsigned int block, beyond;
104 struct ubifs_data_node *dn;
105 struct inode *inode = page->mapping->host;
106 struct ubifs_info *c = inode->i_sb->s_fs_info;
107 loff_t i_size = i_size_read(inode);
108
109 dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
110 inode->i_ino, page->index, i_size, page->flags);
111 ubifs_assert(c, !PageChecked(page));
112 ubifs_assert(c, !PagePrivate(page));
113
114 addr = kmap(page);
115
116 block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
117 beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
118 if (block >= beyond) {
119 /* Reading beyond inode */
120 SetPageChecked(page);
121 memset(addr, 0, PAGE_SIZE);
122 goto out;
123 }
124
125 dn = kmalloc(UBIFS_MAX_DATA_NODE_SZ, GFP_NOFS);
126 if (!dn) {
127 err = -ENOMEM;
128 goto error;
129 }
130
131 i = 0;
132 while (1) {
133 int ret;
134
135 if (block >= beyond) {
136 /* Reading beyond inode */
137 err = -ENOENT;
138 memset(addr, 0, UBIFS_BLOCK_SIZE);
139 } else {
140 ret = read_block(inode, addr, block, dn);
141 if (ret) {
142 err = ret;
143 if (err != -ENOENT)
144 break;
145 } else if (block + 1 == beyond) {
146 int dlen = le32_to_cpu(dn->size);
147 int ilen = i_size & (UBIFS_BLOCK_SIZE - 1);
148
149 if (ilen && ilen < dlen)
150 memset(addr + ilen, 0, dlen - ilen);
151 }
152 }
153 if (++i >= UBIFS_BLOCKS_PER_PAGE)
154 break;
155 block += 1;
156 addr += UBIFS_BLOCK_SIZE;
157 }
158 if (err) {
159 struct ubifs_info *c = inode->i_sb->s_fs_info;
160 if (err == -ENOENT) {
161 /* Not found, so it must be a hole */
162 SetPageChecked(page);
163 dbg_gen("hole");
164 goto out_free;
165 }
166 ubifs_err(c, "cannot read page %lu of inode %lu, error %d",
167 page->index, inode->i_ino, err);
168 goto error;
169 }
170
171 out_free:
172 kfree(dn);
173 out:
174 SetPageUptodate(page);
175 ClearPageError(page);
176 flush_dcache_page(page);
177 kunmap(page);
178 return 0;
179
180 error:
181 kfree(dn);
182 ClearPageUptodate(page);
183 SetPageError(page);
184 flush_dcache_page(page);
185 kunmap(page);
186 return err;
187 }
188
189 /**
190 * release_new_page_budget - release budget of a new page.
191 * @c: UBIFS file-system description object
192 *
193 * This is a helper function which releases budget corresponding to the budget
194 * of one new page of data.
195 */
196 static void release_new_page_budget(struct ubifs_info *c)
197 {
198 struct ubifs_budget_req req = { .recalculate = 1, .new_page = 1 };
199
200 ubifs_release_budget(c, &req);
201 }
202
203 /**
204 * release_existing_page_budget - release budget of an existing page.
205 * @c: UBIFS file-system description object
206 *
207 * This is a helper function which releases budget corresponding to the budget
208 * of changing one one page of data which already exists on the flash media.
209 */
210 static void release_existing_page_budget(struct ubifs_info *c)
211 {
212 struct ubifs_budget_req req = { .dd_growth = c->bi.page_budget};
213
214 ubifs_release_budget(c, &req);
215 }
216
217 static int write_begin_slow(struct address_space *mapping,
218 loff_t pos, unsigned len, struct page **pagep,
219 unsigned flags)
220 {
221 struct inode *inode = mapping->host;
222 struct ubifs_info *c = inode->i_sb->s_fs_info;
223 pgoff_t index = pos >> PAGE_SHIFT;
224 struct ubifs_budget_req req = { .new_page = 1 };
225 int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
226 struct page *page;
227
228 dbg_gen("ino %lu, pos %llu, len %u, i_size %lld",
229 inode->i_ino, pos, len, inode->i_size);
230
231 /*
232 * At the slow path we have to budget before locking the page, because
233 * budgeting may force write-back, which would wait on locked pages and
234 * deadlock if we had the page locked. At this point we do not know
235 * anything about the page, so assume that this is a new page which is
236 * written to a hole. This corresponds to largest budget. Later the
237 * budget will be amended if this is not true.
238 */
239 if (appending)
240 /* We are appending data, budget for inode change */
241 req.dirtied_ino = 1;
242
243 err = ubifs_budget_space(c, &req);
244 if (unlikely(err))
245 return err;
246
247 page = grab_cache_page_write_begin(mapping, index, flags);
248 if (unlikely(!page)) {
249 ubifs_release_budget(c, &req);
250 return -ENOMEM;
251 }
252
253 if (!PageUptodate(page)) {
254 if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE)
255 SetPageChecked(page);
256 else {
257 err = do_readpage(page);
258 if (err) {
259 unlock_page(page);
260 put_page(page);
261 ubifs_release_budget(c, &req);
262 return err;
263 }
264 }
265
266 SetPageUptodate(page);
267 ClearPageError(page);
268 }
269
270 if (PagePrivate(page))
271 /*
272 * The page is dirty, which means it was budgeted twice:
273 * o first time the budget was allocated by the task which
274 * made the page dirty and set the PG_private flag;
275 * o and then we budgeted for it for the second time at the
276 * very beginning of this function.
277 *
278 * So what we have to do is to release the page budget we
279 * allocated.
280 */
281 release_new_page_budget(c);
282 else if (!PageChecked(page))
283 /*
284 * We are changing a page which already exists on the media.
285 * This means that changing the page does not make the amount
286 * of indexing information larger, and this part of the budget
287 * which we have already acquired may be released.
288 */
289 ubifs_convert_page_budget(c);
290
291 if (appending) {
292 struct ubifs_inode *ui = ubifs_inode(inode);
293
294 /*
295 * 'ubifs_write_end()' is optimized from the fast-path part of
296 * 'ubifs_write_begin()' and expects the @ui_mutex to be locked
297 * if data is appended.
298 */
299 mutex_lock(&ui->ui_mutex);
300 if (ui->dirty)
301 /*
302 * The inode is dirty already, so we may free the
303 * budget we allocated.
304 */
305 ubifs_release_dirty_inode_budget(c, ui);
306 }
307
308 *pagep = page;
309 return 0;
310 }
311
312 /**
313 * allocate_budget - allocate budget for 'ubifs_write_begin()'.
314 * @c: UBIFS file-system description object
315 * @page: page to allocate budget for
316 * @ui: UBIFS inode object the page belongs to
317 * @appending: non-zero if the page is appended
318 *
319 * This is a helper function for 'ubifs_write_begin()' which allocates budget
320 * for the operation. The budget is allocated differently depending on whether
321 * this is appending, whether the page is dirty or not, and so on. This
322 * function leaves the @ui->ui_mutex locked in case of appending. Returns zero
323 * in case of success and %-ENOSPC in case of failure.
324 */
325 static int allocate_budget(struct ubifs_info *c, struct page *page,
326 struct ubifs_inode *ui, int appending)
327 {
328 struct ubifs_budget_req req = { .fast = 1 };
329
330 if (PagePrivate(page)) {
331 if (!appending)
332 /*
333 * The page is dirty and we are not appending, which
334 * means no budget is needed at all.
335 */
336 return 0;
337
338 mutex_lock(&ui->ui_mutex);
339 if (ui->dirty)
340 /*
341 * The page is dirty and we are appending, so the inode
342 * has to be marked as dirty. However, it is already
343 * dirty, so we do not need any budget. We may return,
344 * but @ui->ui_mutex hast to be left locked because we
345 * should prevent write-back from flushing the inode
346 * and freeing the budget. The lock will be released in
347 * 'ubifs_write_end()'.
348 */
349 return 0;
350
351 /*
352 * The page is dirty, we are appending, the inode is clean, so
353 * we need to budget the inode change.
354 */
355 req.dirtied_ino = 1;
356 } else {
357 if (PageChecked(page))
358 /*
359 * The page corresponds to a hole and does not
360 * exist on the media. So changing it makes
361 * make the amount of indexing information
362 * larger, and we have to budget for a new
363 * page.
364 */
365 req.new_page = 1;
366 else
367 /*
368 * Not a hole, the change will not add any new
369 * indexing information, budget for page
370 * change.
371 */
372 req.dirtied_page = 1;
373
374 if (appending) {
375 mutex_lock(&ui->ui_mutex);
376 if (!ui->dirty)
377 /*
378 * The inode is clean but we will have to mark
379 * it as dirty because we are appending. This
380 * needs a budget.
381 */
382 req.dirtied_ino = 1;
383 }
384 }
385
386 return ubifs_budget_space(c, &req);
387 }
388
389 /*
390 * This function is called when a page of data is going to be written. Since
391 * the page of data will not necessarily go to the flash straight away, UBIFS
392 * has to reserve space on the media for it, which is done by means of
393 * budgeting.
394 *
395 * This is the hot-path of the file-system and we are trying to optimize it as
396 * much as possible. For this reasons it is split on 2 parts - slow and fast.
397 *
398 * There many budgeting cases:
399 * o a new page is appended - we have to budget for a new page and for
400 * changing the inode; however, if the inode is already dirty, there is
401 * no need to budget for it;
402 * o an existing clean page is changed - we have budget for it; if the page
403 * does not exist on the media (a hole), we have to budget for a new
404 * page; otherwise, we may budget for changing an existing page; the
405 * difference between these cases is that changing an existing page does
406 * not introduce anything new to the FS indexing information, so it does
407 * not grow, and smaller budget is acquired in this case;
408 * o an existing dirty page is changed - no need to budget at all, because
409 * the page budget has been acquired by earlier, when the page has been
410 * marked dirty.
411 *
412 * UBIFS budgeting sub-system may force write-back if it thinks there is no
413 * space to reserve. This imposes some locking restrictions and makes it
414 * impossible to take into account the above cases, and makes it impossible to
415 * optimize budgeting.
416 *
417 * The solution for this is that the fast path of 'ubifs_write_begin()' assumes
418 * there is a plenty of flash space and the budget will be acquired quickly,
419 * without forcing write-back. The slow path does not make this assumption.
420 */
421 static int ubifs_write_begin(struct file *file, struct address_space *mapping,
422 loff_t pos, unsigned len, unsigned flags,
423 struct page **pagep, void **fsdata)
424 {
425 struct inode *inode = mapping->host;
426 struct ubifs_info *c = inode->i_sb->s_fs_info;
427 struct ubifs_inode *ui = ubifs_inode(inode);
428 pgoff_t index = pos >> PAGE_SHIFT;
429 int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
430 int skipped_read = 0;
431 struct page *page;
432
433 ubifs_assert(c, ubifs_inode(inode)->ui_size == inode->i_size);
434 ubifs_assert(c, !c->ro_media && !c->ro_mount);
435
436 if (unlikely(c->ro_error))
437 return -EROFS;
438
439 /* Try out the fast-path part first */
440 page = grab_cache_page_write_begin(mapping, index, flags);
441 if (unlikely(!page))
442 return -ENOMEM;
443
444 if (!PageUptodate(page)) {
445 /* The page is not loaded from the flash */
446 if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE) {
447 /*
448 * We change whole page so no need to load it. But we
449 * do not know whether this page exists on the media or
450 * not, so we assume the latter because it requires
451 * larger budget. The assumption is that it is better
452 * to budget a bit more than to read the page from the
453 * media. Thus, we are setting the @PG_checked flag
454 * here.
455 */
456 SetPageChecked(page);
457 skipped_read = 1;
458 } else {
459 err = do_readpage(page);
460 if (err) {
461 unlock_page(page);
462 put_page(page);
463 return err;
464 }
465 }
466
467 SetPageUptodate(page);
468 ClearPageError(page);
469 }
470
471 err = allocate_budget(c, page, ui, appending);
472 if (unlikely(err)) {
473 ubifs_assert(c, err == -ENOSPC);
474 /*
475 * If we skipped reading the page because we were going to
476 * write all of it, then it is not up to date.
477 */
478 if (skipped_read) {
479 ClearPageChecked(page);
480 ClearPageUptodate(page);
481 }
482 /*
483 * Budgeting failed which means it would have to force
484 * write-back but didn't, because we set the @fast flag in the
485 * request. Write-back cannot be done now, while we have the
486 * page locked, because it would deadlock. Unlock and free
487 * everything and fall-back to slow-path.
488 */
489 if (appending) {
490 ubifs_assert(c, mutex_is_locked(&ui->ui_mutex));
491 mutex_unlock(&ui->ui_mutex);
492 }
493 unlock_page(page);
494 put_page(page);
495
496 return write_begin_slow(mapping, pos, len, pagep, flags);
497 }
498
499 /*
500 * Whee, we acquired budgeting quickly - without involving
501 * garbage-collection, committing or forcing write-back. We return
502 * with @ui->ui_mutex locked if we are appending pages, and unlocked
503 * otherwise. This is an optimization (slightly hacky though).
504 */
505 *pagep = page;
506 return 0;
507
508 }
509
510 /**
511 * cancel_budget - cancel budget.
512 * @c: UBIFS file-system description object
513 * @page: page to cancel budget for
514 * @ui: UBIFS inode object the page belongs to
515 * @appending: non-zero if the page is appended
516 *
517 * This is a helper function for a page write operation. It unlocks the
518 * @ui->ui_mutex in case of appending.
519 */
520 static void cancel_budget(struct ubifs_info *c, struct page *page,
521 struct ubifs_inode *ui, int appending)
522 {
523 if (appending) {
524 if (!ui->dirty)
525 ubifs_release_dirty_inode_budget(c, ui);
526 mutex_unlock(&ui->ui_mutex);
527 }
528 if (!PagePrivate(page)) {
529 if (PageChecked(page))
530 release_new_page_budget(c);
531 else
532 release_existing_page_budget(c);
533 }
534 }
535
536 static int ubifs_write_end(struct file *file, struct address_space *mapping,
537 loff_t pos, unsigned len, unsigned copied,
538 struct page *page, void *fsdata)
539 {
540 struct inode *inode = mapping->host;
541 struct ubifs_inode *ui = ubifs_inode(inode);
542 struct ubifs_info *c = inode->i_sb->s_fs_info;
543 loff_t end_pos = pos + len;
544 int appending = !!(end_pos > inode->i_size);
545
546 dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
547 inode->i_ino, pos, page->index, len, copied, inode->i_size);
548
549 if (unlikely(copied < len && len == PAGE_SIZE)) {
550 /*
551 * VFS copied less data to the page that it intended and
552 * declared in its '->write_begin()' call via the @len
553 * argument. If the page was not up-to-date, and @len was
554 * @PAGE_SIZE, the 'ubifs_write_begin()' function did
555 * not load it from the media (for optimization reasons). This
556 * means that part of the page contains garbage. So read the
557 * page now.
558 */
559 dbg_gen("copied %d instead of %d, read page and repeat",
560 copied, len);
561 cancel_budget(c, page, ui, appending);
562 ClearPageChecked(page);
563
564 /*
565 * Return 0 to force VFS to repeat the whole operation, or the
566 * error code if 'do_readpage()' fails.
567 */
568 copied = do_readpage(page);
569 goto out;
570 }
571
572 if (!PagePrivate(page)) {
573 SetPagePrivate(page);
574 atomic_long_inc(&c->dirty_pg_cnt);
575 __set_page_dirty_nobuffers(page);
576 }
577
578 if (appending) {
579 i_size_write(inode, end_pos);
580 ui->ui_size = end_pos;
581 /*
582 * Note, we do not set @I_DIRTY_PAGES (which means that the
583 * inode has dirty pages), this has been done in
584 * '__set_page_dirty_nobuffers()'.
585 */
586 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
587 ubifs_assert(c, mutex_is_locked(&ui->ui_mutex));
588 mutex_unlock(&ui->ui_mutex);
589 }
590
591 out:
592 unlock_page(page);
593 put_page(page);
594 return copied;
595 }
596
597 /**
598 * populate_page - copy data nodes into a page for bulk-read.
599 * @c: UBIFS file-system description object
600 * @page: page
601 * @bu: bulk-read information
602 * @n: next zbranch slot
603 *
604 * This function returns %0 on success and a negative error code on failure.
605 */
606 static int populate_page(struct ubifs_info *c, struct page *page,
607 struct bu_info *bu, int *n)
608 {
609 int i = 0, nn = *n, offs = bu->zbranch[0].offs, hole = 0, read = 0;
610 struct inode *inode = page->mapping->host;
611 loff_t i_size = i_size_read(inode);
612 unsigned int page_block;
613 void *addr, *zaddr;
614 pgoff_t end_index;
615
616 dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
617 inode->i_ino, page->index, i_size, page->flags);
618
619 addr = zaddr = kmap(page);
620
621 end_index = (i_size - 1) >> PAGE_SHIFT;
622 if (!i_size || page->index > end_index) {
623 hole = 1;
624 memset(addr, 0, PAGE_SIZE);
625 goto out_hole;
626 }
627
628 page_block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
629 while (1) {
630 int err, len, out_len, dlen;
631
632 if (nn >= bu->cnt) {
633 hole = 1;
634 memset(addr, 0, UBIFS_BLOCK_SIZE);
635 } else if (key_block(c, &bu->zbranch[nn].key) == page_block) {
636 struct ubifs_data_node *dn;
637
638 dn = bu->buf + (bu->zbranch[nn].offs - offs);
639
640 ubifs_assert(c, le64_to_cpu(dn->ch.sqnum) >
641 ubifs_inode(inode)->creat_sqnum);
642
643 len = le32_to_cpu(dn->size);
644 if (len <= 0 || len > UBIFS_BLOCK_SIZE)
645 goto out_err;
646
647 dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
648 out_len = UBIFS_BLOCK_SIZE;
649
650 if (ubifs_crypt_is_encrypted(inode)) {
651 err = ubifs_decrypt(inode, dn, &dlen, page_block);
652 if (err)
653 goto out_err;
654 }
655
656 err = ubifs_decompress(c, &dn->data, dlen, addr, &out_len,
657 le16_to_cpu(dn->compr_type));
658 if (err || len != out_len)
659 goto out_err;
660
661 if (len < UBIFS_BLOCK_SIZE)
662 memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
663
664 nn += 1;
665 read = (i << UBIFS_BLOCK_SHIFT) + len;
666 } else if (key_block(c, &bu->zbranch[nn].key) < page_block) {
667 nn += 1;
668 continue;
669 } else {
670 hole = 1;
671 memset(addr, 0, UBIFS_BLOCK_SIZE);
672 }
673 if (++i >= UBIFS_BLOCKS_PER_PAGE)
674 break;
675 addr += UBIFS_BLOCK_SIZE;
676 page_block += 1;
677 }
678
679 if (end_index == page->index) {
680 int len = i_size & (PAGE_SIZE - 1);
681
682 if (len && len < read)
683 memset(zaddr + len, 0, read - len);
684 }
685
686 out_hole:
687 if (hole) {
688 SetPageChecked(page);
689 dbg_gen("hole");
690 }
691
692 SetPageUptodate(page);
693 ClearPageError(page);
694 flush_dcache_page(page);
695 kunmap(page);
696 *n = nn;
697 return 0;
698
699 out_err:
700 ClearPageUptodate(page);
701 SetPageError(page);
702 flush_dcache_page(page);
703 kunmap(page);
704 ubifs_err(c, "bad data node (block %u, inode %lu)",
705 page_block, inode->i_ino);
706 return -EINVAL;
707 }
708
709 /**
710 * ubifs_do_bulk_read - do bulk-read.
711 * @c: UBIFS file-system description object
712 * @bu: bulk-read information
713 * @page1: first page to read
714 *
715 * This function returns %1 if the bulk-read is done, otherwise %0 is returned.
716 */
717 static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
718 struct page *page1)
719 {
720 pgoff_t offset = page1->index, end_index;
721 struct address_space *mapping = page1->mapping;
722 struct inode *inode = mapping->host;
723 struct ubifs_inode *ui = ubifs_inode(inode);
724 int err, page_idx, page_cnt, ret = 0, n = 0;
725 int allocate = bu->buf ? 0 : 1;
726 loff_t isize;
727 gfp_t ra_gfp_mask = readahead_gfp_mask(mapping) & ~__GFP_FS;
728
729 err = ubifs_tnc_get_bu_keys(c, bu);
730 if (err)
731 goto out_warn;
732
733 if (bu->eof) {
734 /* Turn off bulk-read at the end of the file */
735 ui->read_in_a_row = 1;
736 ui->bulk_read = 0;
737 }
738
739 page_cnt = bu->blk_cnt >> UBIFS_BLOCKS_PER_PAGE_SHIFT;
740 if (!page_cnt) {
741 /*
742 * This happens when there are multiple blocks per page and the
743 * blocks for the first page we are looking for, are not
744 * together. If all the pages were like this, bulk-read would
745 * reduce performance, so we turn it off for a while.
746 */
747 goto out_bu_off;
748 }
749
750 if (bu->cnt) {
751 if (allocate) {
752 /*
753 * Allocate bulk-read buffer depending on how many data
754 * nodes we are going to read.
755 */
756 bu->buf_len = bu->zbranch[bu->cnt - 1].offs +
757 bu->zbranch[bu->cnt - 1].len -
758 bu->zbranch[0].offs;
759 ubifs_assert(c, bu->buf_len > 0);
760 ubifs_assert(c, bu->buf_len <= c->leb_size);
761 bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN);
762 if (!bu->buf)
763 goto out_bu_off;
764 }
765
766 err = ubifs_tnc_bulk_read(c, bu);
767 if (err)
768 goto out_warn;
769 }
770
771 err = populate_page(c, page1, bu, &n);
772 if (err)
773 goto out_warn;
774
775 unlock_page(page1);
776 ret = 1;
777
778 isize = i_size_read(inode);
779 if (isize == 0)
780 goto out_free;
781 end_index = ((isize - 1) >> PAGE_SHIFT);
782
783 for (page_idx = 1; page_idx < page_cnt; page_idx++) {
784 pgoff_t page_offset = offset + page_idx;
785 struct page *page;
786
787 if (page_offset > end_index)
788 break;
789 page = pagecache_get_page(mapping, page_offset,
790 FGP_LOCK|FGP_ACCESSED|FGP_CREAT|FGP_NOWAIT,
791 ra_gfp_mask);
792 if (!page)
793 break;
794 if (!PageUptodate(page))
795 err = populate_page(c, page, bu, &n);
796 unlock_page(page);
797 put_page(page);
798 if (err)
799 break;
800 }
801
802 ui->last_page_read = offset + page_idx - 1;
803
804 out_free:
805 if (allocate)
806 kfree(bu->buf);
807 return ret;
808
809 out_warn:
810 ubifs_warn(c, "ignoring error %d and skipping bulk-read", err);
811 goto out_free;
812
813 out_bu_off:
814 ui->read_in_a_row = ui->bulk_read = 0;
815 goto out_free;
816 }
817
818 /**
819 * ubifs_bulk_read - determine whether to bulk-read and, if so, do it.
820 * @page: page from which to start bulk-read.
821 *
822 * Some flash media are capable of reading sequentially at faster rates. UBIFS
823 * bulk-read facility is designed to take advantage of that, by reading in one
824 * go consecutive data nodes that are also located consecutively in the same
825 * LEB. This function returns %1 if a bulk-read is done and %0 otherwise.
826 */
827 static int ubifs_bulk_read(struct page *page)
828 {
829 struct inode *inode = page->mapping->host;
830 struct ubifs_info *c = inode->i_sb->s_fs_info;
831 struct ubifs_inode *ui = ubifs_inode(inode);
832 pgoff_t index = page->index, last_page_read = ui->last_page_read;
833 struct bu_info *bu;
834 int err = 0, allocated = 0;
835
836 ui->last_page_read = index;
837 if (!c->bulk_read)
838 return 0;
839
840 /*
841 * Bulk-read is protected by @ui->ui_mutex, but it is an optimization,
842 * so don't bother if we cannot lock the mutex.
843 */
844 if (!mutex_trylock(&ui->ui_mutex))
845 return 0;
846
847 if (index != last_page_read + 1) {
848 /* Turn off bulk-read if we stop reading sequentially */
849 ui->read_in_a_row = 1;
850 if (ui->bulk_read)
851 ui->bulk_read = 0;
852 goto out_unlock;
853 }
854
855 if (!ui->bulk_read) {
856 ui->read_in_a_row += 1;
857 if (ui->read_in_a_row < 3)
858 goto out_unlock;
859 /* Three reads in a row, so switch on bulk-read */
860 ui->bulk_read = 1;
861 }
862
863 /*
864 * If possible, try to use pre-allocated bulk-read information, which
865 * is protected by @c->bu_mutex.
866 */
867 if (mutex_trylock(&c->bu_mutex))
868 bu = &c->bu;
869 else {
870 bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN);
871 if (!bu)
872 goto out_unlock;
873
874 bu->buf = NULL;
875 allocated = 1;
876 }
877
878 bu->buf_len = c->max_bu_buf_len;
879 data_key_init(c, &bu->key, inode->i_ino,
880 page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT);
881 err = ubifs_do_bulk_read(c, bu, page);
882
883 if (!allocated)
884 mutex_unlock(&c->bu_mutex);
885 else
886 kfree(bu);
887
888 out_unlock:
889 mutex_unlock(&ui->ui_mutex);
890 return err;
891 }
892
893 static int ubifs_readpage(struct file *file, struct page *page)
894 {
895 if (ubifs_bulk_read(page))
896 return 0;
897 do_readpage(page);
898 unlock_page(page);
899 return 0;
900 }
901
902 static int do_writepage(struct page *page, int len)
903 {
904 int err = 0, i, blen;
905 unsigned int block;
906 void *addr;
907 union ubifs_key key;
908 struct inode *inode = page->mapping->host;
909 struct ubifs_info *c = inode->i_sb->s_fs_info;
910
911 #ifdef UBIFS_DEBUG
912 struct ubifs_inode *ui = ubifs_inode(inode);
913 spin_lock(&ui->ui_lock);
914 ubifs_assert(c, page->index <= ui->synced_i_size >> PAGE_SHIFT);
915 spin_unlock(&ui->ui_lock);
916 #endif
917
918 /* Update radix tree tags */
919 set_page_writeback(page);
920
921 addr = kmap(page);
922 block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
923 i = 0;
924 while (len) {
925 blen = min_t(int, len, UBIFS_BLOCK_SIZE);
926 data_key_init(c, &key, inode->i_ino, block);
927 err = ubifs_jnl_write_data(c, inode, &key, addr, blen);
928 if (err)
929 break;
930 if (++i >= UBIFS_BLOCKS_PER_PAGE)
931 break;
932 block += 1;
933 addr += blen;
934 len -= blen;
935 }
936 if (err) {
937 SetPageError(page);
938 ubifs_err(c, "cannot write page %lu of inode %lu, error %d",
939 page->index, inode->i_ino, err);
940 ubifs_ro_mode(c, err);
941 }
942
943 ubifs_assert(c, PagePrivate(page));
944 if (PageChecked(page))
945 release_new_page_budget(c);
946 else
947 release_existing_page_budget(c);
948
949 atomic_long_dec(&c->dirty_pg_cnt);
950 ClearPagePrivate(page);
951 ClearPageChecked(page);
952
953 kunmap(page);
954 unlock_page(page);
955 end_page_writeback(page);
956 return err;
957 }
958
959 /*
960 * When writing-back dirty inodes, VFS first writes-back pages belonging to the
961 * inode, then the inode itself. For UBIFS this may cause a problem. Consider a
962 * situation when a we have an inode with size 0, then a megabyte of data is
963 * appended to the inode, then write-back starts and flushes some amount of the
964 * dirty pages, the journal becomes full, commit happens and finishes, and then
965 * an unclean reboot happens. When the file system is mounted next time, the
966 * inode size would still be 0, but there would be many pages which are beyond
967 * the inode size, they would be indexed and consume flash space. Because the
968 * journal has been committed, the replay would not be able to detect this
969 * situation and correct the inode size. This means UBIFS would have to scan
970 * whole index and correct all inode sizes, which is long an unacceptable.
971 *
972 * To prevent situations like this, UBIFS writes pages back only if they are
973 * within the last synchronized inode size, i.e. the size which has been
974 * written to the flash media last time. Otherwise, UBIFS forces inode
975 * write-back, thus making sure the on-flash inode contains current inode size,
976 * and then keeps writing pages back.
977 *
978 * Some locking issues explanation. 'ubifs_writepage()' first is called with
979 * the page locked, and it locks @ui_mutex. However, write-back does take inode
980 * @i_mutex, which means other VFS operations may be run on this inode at the
981 * same time. And the problematic one is truncation to smaller size, from where
982 * we have to call 'truncate_setsize()', which first changes @inode->i_size,
983 * then drops the truncated pages. And while dropping the pages, it takes the
984 * page lock. This means that 'do_truncation()' cannot call 'truncate_setsize()'
985 * with @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'.
986 * This means that @inode->i_size is changed while @ui_mutex is unlocked.
987 *
988 * XXX(truncate): with the new truncate sequence this is not true anymore,
989 * and the calls to truncate_setsize can be move around freely. They should
990 * be moved to the very end of the truncate sequence.
991 *
992 * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond
993 * inode size. How do we do this if @inode->i_size may became smaller while we
994 * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the
995 * @ui->ui_isize "shadow" field which UBIFS uses instead of @inode->i_size
996 * internally and updates it under @ui_mutex.
997 *
998 * Q: why we do not worry that if we race with truncation, we may end up with a
999 * situation when the inode is truncated while we are in the middle of
1000 * 'do_writepage()', so we do write beyond inode size?
1001 * A: If we are in the middle of 'do_writepage()', truncation would be locked
1002 * on the page lock and it would not write the truncated inode node to the
1003 * journal before we have finished.
1004 */
1005 static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
1006 {
1007 struct inode *inode = page->mapping->host;
1008 struct ubifs_info *c = inode->i_sb->s_fs_info;
1009 struct ubifs_inode *ui = ubifs_inode(inode);
1010 loff_t i_size = i_size_read(inode), synced_i_size;
1011 pgoff_t end_index = i_size >> PAGE_SHIFT;
1012 int err, len = i_size & (PAGE_SIZE - 1);
1013 void *kaddr;
1014
1015 dbg_gen("ino %lu, pg %lu, pg flags %#lx",
1016 inode->i_ino, page->index, page->flags);
1017 ubifs_assert(c, PagePrivate(page));
1018
1019 /* Is the page fully outside @i_size? (truncate in progress) */
1020 if (page->index > end_index || (page->index == end_index && !len)) {
1021 err = 0;
1022 goto out_unlock;
1023 }
1024
1025 spin_lock(&ui->ui_lock);
1026 synced_i_size = ui->synced_i_size;
1027 spin_unlock(&ui->ui_lock);
1028
1029 /* Is the page fully inside @i_size? */
1030 if (page->index < end_index) {
1031 if (page->index >= synced_i_size >> PAGE_SHIFT) {
1032 err = inode->i_sb->s_op->write_inode(inode, NULL);
1033 if (err)
1034 goto out_unlock;
1035 /*
1036 * The inode has been written, but the write-buffer has
1037 * not been synchronized, so in case of an unclean
1038 * reboot we may end up with some pages beyond inode
1039 * size, but they would be in the journal (because
1040 * commit flushes write buffers) and recovery would deal
1041 * with this.
1042 */
1043 }
1044 return do_writepage(page, PAGE_SIZE);
1045 }
1046
1047 /*
1048 * The page straddles @i_size. It must be zeroed out on each and every
1049 * writepage invocation because it may be mmapped. "A file is mapped
1050 * in multiples of the page size. For a file that is not a multiple of
1051 * the page size, the remaining memory is zeroed when mapped, and
1052 * writes to that region are not written out to the file."
1053 */
1054 kaddr = kmap_atomic(page);
1055 memset(kaddr + len, 0, PAGE_SIZE - len);
1056 flush_dcache_page(page);
1057 kunmap_atomic(kaddr);
1058
1059 if (i_size > synced_i_size) {
1060 err = inode->i_sb->s_op->write_inode(inode, NULL);
1061 if (err)
1062 goto out_unlock;
1063 }
1064
1065 return do_writepage(page, len);
1066
1067 out_unlock:
1068 unlock_page(page);
1069 return err;
1070 }
1071
1072 /**
1073 * do_attr_changes - change inode attributes.
1074 * @inode: inode to change attributes for
1075 * @attr: describes attributes to change
1076 */
1077 static void do_attr_changes(struct inode *inode, const struct iattr *attr)
1078 {
1079 if (attr->ia_valid & ATTR_UID)
1080 inode->i_uid = attr->ia_uid;
1081 if (attr->ia_valid & ATTR_GID)
1082 inode->i_gid = attr->ia_gid;
1083 if (attr->ia_valid & ATTR_ATIME)
1084 inode->i_atime = attr->ia_atime;
1085 if (attr->ia_valid & ATTR_MTIME)
1086 inode->i_mtime = attr->ia_mtime;
1087 if (attr->ia_valid & ATTR_CTIME)
1088 inode->i_ctime = attr->ia_ctime;
1089 if (attr->ia_valid & ATTR_MODE) {
1090 umode_t mode = attr->ia_mode;
1091
1092 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
1093 mode &= ~S_ISGID;
1094 inode->i_mode = mode;
1095 }
1096 }
1097
1098 /**
1099 * do_truncation - truncate an inode.
1100 * @c: UBIFS file-system description object
1101 * @inode: inode to truncate
1102 * @attr: inode attribute changes description
1103 *
1104 * This function implements VFS '->setattr()' call when the inode is truncated
1105 * to a smaller size. Returns zero in case of success and a negative error code
1106 * in case of failure.
1107 */
1108 static int do_truncation(struct ubifs_info *c, struct inode *inode,
1109 const struct iattr *attr)
1110 {
1111 int err;
1112 struct ubifs_budget_req req;
1113 loff_t old_size = inode->i_size, new_size = attr->ia_size;
1114 int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1;
1115 struct ubifs_inode *ui = ubifs_inode(inode);
1116
1117 dbg_gen("ino %lu, size %lld -> %lld", inode->i_ino, old_size, new_size);
1118 memset(&req, 0, sizeof(struct ubifs_budget_req));
1119
1120 /*
1121 * If this is truncation to a smaller size, and we do not truncate on a
1122 * block boundary, budget for changing one data block, because the last
1123 * block will be re-written.
1124 */
1125 if (new_size & (UBIFS_BLOCK_SIZE - 1))
1126 req.dirtied_page = 1;
1127
1128 req.dirtied_ino = 1;
1129 /* A funny way to budget for truncation node */
1130 req.dirtied_ino_d = UBIFS_TRUN_NODE_SZ;
1131 err = ubifs_budget_space(c, &req);
1132 if (err) {
1133 /*
1134 * Treat truncations to zero as deletion and always allow them,
1135 * just like we do for '->unlink()'.
1136 */
1137 if (new_size || err != -ENOSPC)
1138 return err;
1139 budgeted = 0;
1140 }
1141
1142 truncate_setsize(inode, new_size);
1143
1144 if (offset) {
1145 pgoff_t index = new_size >> PAGE_SHIFT;
1146 struct page *page;
1147
1148 page = find_lock_page(inode->i_mapping, index);
1149 if (page) {
1150 if (PageDirty(page)) {
1151 /*
1152 * 'ubifs_jnl_truncate()' will try to truncate
1153 * the last data node, but it contains
1154 * out-of-date data because the page is dirty.
1155 * Write the page now, so that
1156 * 'ubifs_jnl_truncate()' will see an already
1157 * truncated (and up to date) data node.
1158 */
1159 ubifs_assert(c, PagePrivate(page));
1160
1161 clear_page_dirty_for_io(page);
1162 if (UBIFS_BLOCKS_PER_PAGE_SHIFT)
1163 offset = new_size &
1164 (PAGE_SIZE - 1);
1165 err = do_writepage(page, offset);
1166 put_page(page);
1167 if (err)
1168 goto out_budg;
1169 /*
1170 * We could now tell 'ubifs_jnl_truncate()' not
1171 * to read the last block.
1172 */
1173 } else {
1174 /*
1175 * We could 'kmap()' the page and pass the data
1176 * to 'ubifs_jnl_truncate()' to save it from
1177 * having to read it.
1178 */
1179 unlock_page(page);
1180 put_page(page);
1181 }
1182 }
1183 }
1184
1185 mutex_lock(&ui->ui_mutex);
1186 ui->ui_size = inode->i_size;
1187 /* Truncation changes inode [mc]time */
1188 inode->i_mtime = inode->i_ctime = current_time(inode);
1189 /* Other attributes may be changed at the same time as well */
1190 do_attr_changes(inode, attr);
1191 err = ubifs_jnl_truncate(c, inode, old_size, new_size);
1192 mutex_unlock(&ui->ui_mutex);
1193
1194 out_budg:
1195 if (budgeted)
1196 ubifs_release_budget(c, &req);
1197 else {
1198 c->bi.nospace = c->bi.nospace_rp = 0;
1199 smp_wmb();
1200 }
1201 return err;
1202 }
1203
1204 /**
1205 * do_setattr - change inode attributes.
1206 * @c: UBIFS file-system description object
1207 * @inode: inode to change attributes for
1208 * @attr: inode attribute changes description
1209 *
1210 * This function implements VFS '->setattr()' call for all cases except
1211 * truncations to smaller size. Returns zero in case of success and a negative
1212 * error code in case of failure.
1213 */
1214 static int do_setattr(struct ubifs_info *c, struct inode *inode,
1215 const struct iattr *attr)
1216 {
1217 int err, release;
1218 loff_t new_size = attr->ia_size;
1219 struct ubifs_inode *ui = ubifs_inode(inode);
1220 struct ubifs_budget_req req = { .dirtied_ino = 1,
1221 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
1222
1223 err = ubifs_budget_space(c, &req);
1224 if (err)
1225 return err;
1226
1227 if (attr->ia_valid & ATTR_SIZE) {
1228 dbg_gen("size %lld -> %lld", inode->i_size, new_size);
1229 truncate_setsize(inode, new_size);
1230 }
1231
1232 mutex_lock(&ui->ui_mutex);
1233 if (attr->ia_valid & ATTR_SIZE) {
1234 /* Truncation changes inode [mc]time */
1235 inode->i_mtime = inode->i_ctime = current_time(inode);
1236 /* 'truncate_setsize()' changed @i_size, update @ui_size */
1237 ui->ui_size = inode->i_size;
1238 }
1239
1240 do_attr_changes(inode, attr);
1241
1242 release = ui->dirty;
1243 if (attr->ia_valid & ATTR_SIZE)
1244 /*
1245 * Inode length changed, so we have to make sure
1246 * @I_DIRTY_DATASYNC is set.
1247 */
1248 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1249 else
1250 mark_inode_dirty_sync(inode);
1251 mutex_unlock(&ui->ui_mutex);
1252
1253 if (release)
1254 ubifs_release_budget(c, &req);
1255 if (IS_SYNC(inode))
1256 err = inode->i_sb->s_op->write_inode(inode, NULL);
1257 return err;
1258 }
1259
1260 int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
1261 {
1262 int err;
1263 struct inode *inode = d_inode(dentry);
1264 struct ubifs_info *c = inode->i_sb->s_fs_info;
1265
1266 dbg_gen("ino %lu, mode %#x, ia_valid %#x",
1267 inode->i_ino, inode->i_mode, attr->ia_valid);
1268 err = setattr_prepare(dentry, attr);
1269 if (err)
1270 return err;
1271
1272 err = dbg_check_synced_i_size(c, inode);
1273 if (err)
1274 return err;
1275
1276 err = fscrypt_prepare_setattr(dentry, attr);
1277 if (err)
1278 return err;
1279
1280 if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size < inode->i_size)
1281 /* Truncation to a smaller size */
1282 err = do_truncation(c, inode, attr);
1283 else
1284 err = do_setattr(c, inode, attr);
1285
1286 return err;
1287 }
1288
1289 static void ubifs_invalidatepage(struct page *page, unsigned int offset,
1290 unsigned int length)
1291 {
1292 struct inode *inode = page->mapping->host;
1293 struct ubifs_info *c = inode->i_sb->s_fs_info;
1294
1295 ubifs_assert(c, PagePrivate(page));
1296 if (offset || length < PAGE_SIZE)
1297 /* Partial page remains dirty */
1298 return;
1299
1300 if (PageChecked(page))
1301 release_new_page_budget(c);
1302 else
1303 release_existing_page_budget(c);
1304
1305 atomic_long_dec(&c->dirty_pg_cnt);
1306 ClearPagePrivate(page);
1307 ClearPageChecked(page);
1308 }
1309
1310 int ubifs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
1311 {
1312 struct inode *inode = file->f_mapping->host;
1313 struct ubifs_info *c = inode->i_sb->s_fs_info;
1314 int err;
1315
1316 dbg_gen("syncing inode %lu", inode->i_ino);
1317
1318 if (c->ro_mount)
1319 /*
1320 * For some really strange reasons VFS does not filter out
1321 * 'fsync()' for R/O mounted file-systems as per 2.6.39.
1322 */
1323 return 0;
1324
1325 err = file_write_and_wait_range(file, start, end);
1326 if (err)
1327 return err;
1328 inode_lock(inode);
1329
1330 /* Synchronize the inode unless this is a 'datasync()' call. */
1331 if (!datasync || (inode->i_state & I_DIRTY_DATASYNC)) {
1332 err = inode->i_sb->s_op->write_inode(inode, NULL);
1333 if (err)
1334 goto out;
1335 }
1336
1337 /*
1338 * Nodes related to this inode may still sit in a write-buffer. Flush
1339 * them.
1340 */
1341 err = ubifs_sync_wbufs_by_inode(c, inode);
1342 out:
1343 inode_unlock(inode);
1344 return err;
1345 }
1346
1347 /**
1348 * mctime_update_needed - check if mtime or ctime update is needed.
1349 * @inode: the inode to do the check for
1350 * @now: current time
1351 *
1352 * This helper function checks if the inode mtime/ctime should be updated or
1353 * not. If current values of the time-stamps are within the UBIFS inode time
1354 * granularity, they are not updated. This is an optimization.
1355 */
1356 static inline int mctime_update_needed(const struct inode *inode,
1357 const struct timespec64 *now)
1358 {
1359 if (!timespec64_equal(&inode->i_mtime, now) ||
1360 !timespec64_equal(&inode->i_ctime, now))
1361 return 1;
1362 return 0;
1363 }
1364
1365 /**
1366 * ubifs_update_time - update time of inode.
1367 * @inode: inode to update
1368 *
1369 * This function updates time of the inode.
1370 */
1371 int ubifs_update_time(struct inode *inode, struct timespec64 *time,
1372 int flags)
1373 {
1374 struct ubifs_inode *ui = ubifs_inode(inode);
1375 struct ubifs_info *c = inode->i_sb->s_fs_info;
1376 struct ubifs_budget_req req = { .dirtied_ino = 1,
1377 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
1378 int err, release;
1379
1380 if (!IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT))
1381 return generic_update_time(inode, time, flags);
1382
1383 err = ubifs_budget_space(c, &req);
1384 if (err)
1385 return err;
1386
1387 mutex_lock(&ui->ui_mutex);
1388 if (flags & S_ATIME)
1389 inode->i_atime = *time;
1390 if (flags & S_CTIME)
1391 inode->i_ctime = *time;
1392 if (flags & S_MTIME)
1393 inode->i_mtime = *time;
1394
1395 release = ui->dirty;
1396 __mark_inode_dirty(inode, I_DIRTY_SYNC);
1397 mutex_unlock(&ui->ui_mutex);
1398 if (release)
1399 ubifs_release_budget(c, &req);
1400 return 0;
1401 }
1402
1403 /**
1404 * update_mctime - update mtime and ctime of an inode.
1405 * @inode: inode to update
1406 *
1407 * This function updates mtime and ctime of the inode if it is not equivalent to
1408 * current time. Returns zero in case of success and a negative error code in
1409 * case of failure.
1410 */
1411 static int update_mctime(struct inode *inode)
1412 {
1413 struct timespec64 now = current_time(inode);
1414 struct ubifs_inode *ui = ubifs_inode(inode);
1415 struct ubifs_info *c = inode->i_sb->s_fs_info;
1416
1417 if (mctime_update_needed(inode, &now)) {
1418 int err, release;
1419 struct ubifs_budget_req req = { .dirtied_ino = 1,
1420 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
1421
1422 err = ubifs_budget_space(c, &req);
1423 if (err)
1424 return err;
1425
1426 mutex_lock(&ui->ui_mutex);
1427 inode->i_mtime = inode->i_ctime = current_time(inode);
1428 release = ui->dirty;
1429 mark_inode_dirty_sync(inode);
1430 mutex_unlock(&ui->ui_mutex);
1431 if (release)
1432 ubifs_release_budget(c, &req);
1433 }
1434
1435 return 0;
1436 }
1437
1438 static ssize_t ubifs_write_iter(struct kiocb *iocb, struct iov_iter *from)
1439 {
1440 int err = update_mctime(file_inode(iocb->ki_filp));
1441 if (err)
1442 return err;
1443
1444 return generic_file_write_iter(iocb, from);
1445 }
1446
1447 static int ubifs_set_page_dirty(struct page *page)
1448 {
1449 int ret;
1450 struct inode *inode = page->mapping->host;
1451 struct ubifs_info *c = inode->i_sb->s_fs_info;
1452
1453 ret = __set_page_dirty_nobuffers(page);
1454 /*
1455 * An attempt to dirty a page without budgeting for it - should not
1456 * happen.
1457 */
1458 ubifs_assert(c, ret == 0);
1459 return ret;
1460 }
1461
1462 #ifdef CONFIG_MIGRATION
1463 static int ubifs_migrate_page(struct address_space *mapping,
1464 struct page *newpage, struct page *page, enum migrate_mode mode)
1465 {
1466 int rc;
1467
1468 rc = migrate_page_move_mapping(mapping, newpage, page, 0);
1469 if (rc != MIGRATEPAGE_SUCCESS)
1470 return rc;
1471
1472 if (PagePrivate(page)) {
1473 ClearPagePrivate(page);
1474 SetPagePrivate(newpage);
1475 }
1476
1477 if (mode != MIGRATE_SYNC_NO_COPY)
1478 migrate_page_copy(newpage, page);
1479 else
1480 migrate_page_states(newpage, page);
1481 return MIGRATEPAGE_SUCCESS;
1482 }
1483 #endif
1484
1485 static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
1486 {
1487 struct inode *inode = page->mapping->host;
1488 struct ubifs_info *c = inode->i_sb->s_fs_info;
1489
1490 /*
1491 * An attempt to release a dirty page without budgeting for it - should
1492 * not happen.
1493 */
1494 if (PageWriteback(page))
1495 return 0;
1496 ubifs_assert(c, PagePrivate(page));
1497 ubifs_assert(c, 0);
1498 ClearPagePrivate(page);
1499 ClearPageChecked(page);
1500 return 1;
1501 }
1502
1503 /*
1504 * mmap()d file has taken write protection fault and is being made writable.
1505 * UBIFS must ensure page is budgeted for.
1506 */
1507 static vm_fault_t ubifs_vm_page_mkwrite(struct vm_fault *vmf)
1508 {
1509 struct page *page = vmf->page;
1510 struct inode *inode = file_inode(vmf->vma->vm_file);
1511 struct ubifs_info *c = inode->i_sb->s_fs_info;
1512 struct timespec64 now = current_time(inode);
1513 struct ubifs_budget_req req = { .new_page = 1 };
1514 int err, update_time;
1515
1516 dbg_gen("ino %lu, pg %lu, i_size %lld", inode->i_ino, page->index,
1517 i_size_read(inode));
1518 ubifs_assert(c, !c->ro_media && !c->ro_mount);
1519
1520 if (unlikely(c->ro_error))
1521 return VM_FAULT_SIGBUS; /* -EROFS */
1522
1523 /*
1524 * We have not locked @page so far so we may budget for changing the
1525 * page. Note, we cannot do this after we locked the page, because
1526 * budgeting may cause write-back which would cause deadlock.
1527 *
1528 * At the moment we do not know whether the page is dirty or not, so we
1529 * assume that it is not and budget for a new page. We could look at
1530 * the @PG_private flag and figure this out, but we may race with write
1531 * back and the page state may change by the time we lock it, so this
1532 * would need additional care. We do not bother with this at the
1533 * moment, although it might be good idea to do. Instead, we allocate
1534 * budget for a new page and amend it later on if the page was in fact
1535 * dirty.
1536 *
1537 * The budgeting-related logic of this function is similar to what we
1538 * do in 'ubifs_write_begin()' and 'ubifs_write_end()'. Glance there
1539 * for more comments.
1540 */
1541 update_time = mctime_update_needed(inode, &now);
1542 if (update_time)
1543 /*
1544 * We have to change inode time stamp which requires extra
1545 * budgeting.
1546 */
1547 req.dirtied_ino = 1;
1548
1549 err = ubifs_budget_space(c, &req);
1550 if (unlikely(err)) {
1551 if (err == -ENOSPC)
1552 ubifs_warn(c, "out of space for mmapped file (inode number %lu)",
1553 inode->i_ino);
1554 return VM_FAULT_SIGBUS;
1555 }
1556
1557 lock_page(page);
1558 if (unlikely(page->mapping != inode->i_mapping ||
1559 page_offset(page) > i_size_read(inode))) {
1560 /* Page got truncated out from underneath us */
1561 goto sigbus;
1562 }
1563
1564 if (PagePrivate(page))
1565 release_new_page_budget(c);
1566 else {
1567 if (!PageChecked(page))
1568 ubifs_convert_page_budget(c);
1569 SetPagePrivate(page);
1570 atomic_long_inc(&c->dirty_pg_cnt);
1571 __set_page_dirty_nobuffers(page);
1572 }
1573
1574 if (update_time) {
1575 int release;
1576 struct ubifs_inode *ui = ubifs_inode(inode);
1577
1578 mutex_lock(&ui->ui_mutex);
1579 inode->i_mtime = inode->i_ctime = current_time(inode);
1580 release = ui->dirty;
1581 mark_inode_dirty_sync(inode);
1582 mutex_unlock(&ui->ui_mutex);
1583 if (release)
1584 ubifs_release_dirty_inode_budget(c, ui);
1585 }
1586
1587 wait_for_stable_page(page);
1588 return VM_FAULT_LOCKED;
1589
1590 sigbus:
1591 unlock_page(page);
1592 ubifs_release_budget(c, &req);
1593 return VM_FAULT_SIGBUS;
1594 }
1595
1596 static const struct vm_operations_struct ubifs_file_vm_ops = {
1597 .fault = filemap_fault,
1598 .map_pages = filemap_map_pages,
1599 .page_mkwrite = ubifs_vm_page_mkwrite,
1600 };
1601
1602 static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1603 {
1604 int err;
1605
1606 err = generic_file_mmap(file, vma);
1607 if (err)
1608 return err;
1609 vma->vm_ops = &ubifs_file_vm_ops;
1610
1611 if (IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT))
1612 file_accessed(file);
1613
1614 return 0;
1615 }
1616
1617 static const char *ubifs_get_link(struct dentry *dentry,
1618 struct inode *inode,
1619 struct delayed_call *done)
1620 {
1621 struct ubifs_inode *ui = ubifs_inode(inode);
1622
1623 if (!IS_ENCRYPTED(inode))
1624 return ui->data;
1625
1626 if (!dentry)
1627 return ERR_PTR(-ECHILD);
1628
1629 return fscrypt_get_symlink(inode, ui->data, ui->data_len, done);
1630 }
1631
1632 const struct address_space_operations ubifs_file_address_operations = {
1633 .readpage = ubifs_readpage,
1634 .writepage = ubifs_writepage,
1635 .write_begin = ubifs_write_begin,
1636 .write_end = ubifs_write_end,
1637 .invalidatepage = ubifs_invalidatepage,
1638 .set_page_dirty = ubifs_set_page_dirty,
1639 #ifdef CONFIG_MIGRATION
1640 .migratepage = ubifs_migrate_page,
1641 #endif
1642 .releasepage = ubifs_releasepage,
1643 };
1644
1645 const struct inode_operations ubifs_file_inode_operations = {
1646 .setattr = ubifs_setattr,
1647 .getattr = ubifs_getattr,
1648 #ifdef CONFIG_UBIFS_FS_XATTR
1649 .listxattr = ubifs_listxattr,
1650 #endif
1651 .update_time = ubifs_update_time,
1652 };
1653
1654 const struct inode_operations ubifs_symlink_inode_operations = {
1655 .get_link = ubifs_get_link,
1656 .setattr = ubifs_setattr,
1657 .getattr = ubifs_getattr,
1658 #ifdef CONFIG_UBIFS_FS_XATTR
1659 .listxattr = ubifs_listxattr,
1660 #endif
1661 .update_time = ubifs_update_time,
1662 };
1663
1664 const struct file_operations ubifs_file_operations = {
1665 .llseek = generic_file_llseek,
1666 .read_iter = generic_file_read_iter,
1667 .write_iter = ubifs_write_iter,
1668 .mmap = ubifs_file_mmap,
1669 .fsync = ubifs_fsync,
1670 .unlocked_ioctl = ubifs_ioctl,
1671 .splice_read = generic_file_splice_read,
1672 .splice_write = iter_file_splice_write,
1673 .open = fscrypt_file_open,
1674 #ifdef CONFIG_COMPAT
1675 .compat_ioctl = ubifs_compat_ioctl,
1676 #endif
1677 };