blob: bf37374567fa745c63c9f4698d929811544af0e3 [file] [log] [blame]
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
21 */
22
23/*
24 * This file implements VFS file and inode operations of regular files, device
25 * nodes and symlinks as well as address space operations.
26 *
27 * UBIFS uses 2 page flags: PG_private and PG_checked. PG_private is set if the
28 * page is dirty and is used for budgeting purposes - dirty pages should not be
29 * budgeted. The PG_checked flag is set if full budgeting is required for the
30 * page e.g., when it corresponds to a file hole or it is just beyond the file
31 * size. The budgeting is done in 'ubifs_write_begin()', because it is OK to
32 * fail in this function, and the budget is released in 'ubifs_write_end()'. So
33 * the PG_private and PG_checked flags carry the information about how the page
34 * was budgeted, to make it possible to release the budget properly.
35 *
36 * A thing to keep in mind: inode's 'i_mutex' is locked in most VFS operations
37 * we implement. However, this is not true for '->writepage()', which might be
38 * called with 'i_mutex' unlocked. For example, when pdflush is performing
39 * write-back, it calls 'writepage()' with unlocked 'i_mutex', although the
40 * inode has 'I_LOCK' flag in this case. At "normal" work-paths 'i_mutex' is
41 * locked in '->writepage', e.g. in "sys_write -> alloc_pages -> direct reclaim
42 * path'. So, in '->writepage()' we are only guaranteed that the page is
43 * locked.
44 *
45 * Similarly, 'i_mutex' does not have to be locked in readpage(), e.g.,
46 * readahead path does not have it locked ("sys_read -> generic_file_aio_read
47 * -> ondemand_readahead -> readpage"). In case of readahead, 'I_LOCK' flag is
48 * not set as well. However, UBIFS disables readahead.
49 *
50 * This, for example means that there might be 2 concurrent '->writepage()'
51 * calls for the same inode, but different inode dirty pages.
52 */
53
54#include "ubifs.h"
55#include <linux/mount.h>
Al Viro3f8206d2008-07-26 03:46:43 -040056#include <linux/namei.h>
Artem Bityutskiy1e517642008-07-14 19:08:37 +030057
58static int read_block(struct inode *inode, void *addr, unsigned int block,
59 struct ubifs_data_node *dn)
60{
61 struct ubifs_info *c = inode->i_sb->s_fs_info;
62 int err, len, out_len;
63 union ubifs_key key;
64 unsigned int dlen;
65
66 data_key_init(c, &key, inode->i_ino, block);
67 err = ubifs_tnc_lookup(c, &key, dn);
68 if (err) {
69 if (err == -ENOENT)
70 /* Not found, so it must be a hole */
71 memset(addr, 0, UBIFS_BLOCK_SIZE);
72 return err;
73 }
74
Artem Bityutskiyf92b9822008-12-28 11:34:26 +020075 ubifs_assert(le64_to_cpu(dn->ch.sqnum) >
76 ubifs_inode(inode)->creat_sqnum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +030077 len = le32_to_cpu(dn->size);
78 if (len <= 0 || len > UBIFS_BLOCK_SIZE)
79 goto dump;
80
81 dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
82 out_len = UBIFS_BLOCK_SIZE;
83 err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
84 le16_to_cpu(dn->compr_type));
85 if (err || len != out_len)
86 goto dump;
87
88 /*
89 * Data length can be less than a full block, even for blocks that are
90 * not the last in the file (e.g., as a result of making a hole and
91 * appending data). Ensure that the remainder is zeroed out.
92 */
93 if (len < UBIFS_BLOCK_SIZE)
94 memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
95
96 return 0;
97
98dump:
99 ubifs_err("bad data node (block %u, inode %lu)",
100 block, inode->i_ino);
101 dbg_dump_node(c, dn);
102 return -EINVAL;
103}
104
105static int do_readpage(struct page *page)
106{
107 void *addr;
108 int err = 0, i;
109 unsigned int block, beyond;
110 struct ubifs_data_node *dn;
111 struct inode *inode = page->mapping->host;
112 loff_t i_size = i_size_read(inode);
113
114 dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
115 inode->i_ino, page->index, i_size, page->flags);
116 ubifs_assert(!PageChecked(page));
117 ubifs_assert(!PagePrivate(page));
118
119 addr = kmap(page);
120
121 block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
122 beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
123 if (block >= beyond) {
124 /* Reading beyond inode */
125 SetPageChecked(page);
126 memset(addr, 0, PAGE_CACHE_SIZE);
127 goto out;
128 }
129
130 dn = kmalloc(UBIFS_MAX_DATA_NODE_SZ, GFP_NOFS);
131 if (!dn) {
132 err = -ENOMEM;
133 goto error;
134 }
135
136 i = 0;
137 while (1) {
138 int ret;
139
140 if (block >= beyond) {
141 /* Reading beyond inode */
142 err = -ENOENT;
143 memset(addr, 0, UBIFS_BLOCK_SIZE);
144 } else {
145 ret = read_block(inode, addr, block, dn);
146 if (ret) {
147 err = ret;
148 if (err != -ENOENT)
149 break;
Adrian Huntered382d52008-09-05 16:17:42 +0300150 } else if (block + 1 == beyond) {
151 int dlen = le32_to_cpu(dn->size);
152 int ilen = i_size & (UBIFS_BLOCK_SIZE - 1);
153
154 if (ilen && ilen < dlen)
155 memset(addr + ilen, 0, dlen - ilen);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300156 }
157 }
158 if (++i >= UBIFS_BLOCKS_PER_PAGE)
159 break;
160 block += 1;
161 addr += UBIFS_BLOCK_SIZE;
162 }
163 if (err) {
164 if (err == -ENOENT) {
165 /* Not found, so it must be a hole */
166 SetPageChecked(page);
167 dbg_gen("hole");
168 goto out_free;
169 }
170 ubifs_err("cannot read page %lu of inode %lu, error %d",
171 page->index, inode->i_ino, err);
172 goto error;
173 }
174
175out_free:
176 kfree(dn);
177out:
178 SetPageUptodate(page);
179 ClearPageError(page);
180 flush_dcache_page(page);
181 kunmap(page);
182 return 0;
183
184error:
185 kfree(dn);
186 ClearPageUptodate(page);
187 SetPageError(page);
188 flush_dcache_page(page);
189 kunmap(page);
190 return err;
191}
192
193/**
194 * release_new_page_budget - release budget of a new page.
195 * @c: UBIFS file-system description object
196 *
197 * This is a helper function which releases budget corresponding to the budget
198 * of one new page of data.
199 */
200static void release_new_page_budget(struct ubifs_info *c)
201{
202 struct ubifs_budget_req req = { .recalculate = 1, .new_page = 1 };
203
204 ubifs_release_budget(c, &req);
205}
206
207/**
208 * release_existing_page_budget - release budget of an existing page.
209 * @c: UBIFS file-system description object
210 *
211 * This is a helper function which releases budget corresponding to the budget
212 * of changing one one page of data which already exists on the flash media.
213 */
214static void release_existing_page_budget(struct ubifs_info *c)
215{
216 struct ubifs_budget_req req = { .dd_growth = c->page_budget};
217
218 ubifs_release_budget(c, &req);
219}
220
221static int write_begin_slow(struct address_space *mapping,
Nick Piggin54566b22009-01-04 12:00:53 -0800222 loff_t pos, unsigned len, struct page **pagep,
223 unsigned flags)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300224{
225 struct inode *inode = mapping->host;
226 struct ubifs_info *c = inode->i_sb->s_fs_info;
227 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
228 struct ubifs_budget_req req = { .new_page = 1 };
229 int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
230 struct page *page;
231
232 dbg_gen("ino %lu, pos %llu, len %u, i_size %lld",
233 inode->i_ino, pos, len, inode->i_size);
234
235 /*
236 * At the slow path we have to budget before locking the page, because
237 * budgeting may force write-back, which would wait on locked pages and
238 * deadlock if we had the page locked. At this point we do not know
239 * anything about the page, so assume that this is a new page which is
240 * written to a hole. This corresponds to largest budget. Later the
241 * budget will be amended if this is not true.
242 */
243 if (appending)
244 /* We are appending data, budget for inode change */
245 req.dirtied_ino = 1;
246
247 err = ubifs_budget_space(c, &req);
248 if (unlikely(err))
249 return err;
250
Nick Piggin54566b22009-01-04 12:00:53 -0800251 page = grab_cache_page_write_begin(mapping, index, flags);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300252 if (unlikely(!page)) {
253 ubifs_release_budget(c, &req);
254 return -ENOMEM;
255 }
256
257 if (!PageUptodate(page)) {
Artem Bityutskiy7bbe5b52008-12-09 11:02:51 -0500258 if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300259 SetPageChecked(page);
260 else {
261 err = do_readpage(page);
262 if (err) {
263 unlock_page(page);
264 page_cache_release(page);
265 return err;
266 }
267 }
268
269 SetPageUptodate(page);
270 ClearPageError(page);
271 }
272
273 if (PagePrivate(page))
274 /*
275 * The page is dirty, which means it was budgeted twice:
276 * o first time the budget was allocated by the task which
277 * made the page dirty and set the PG_private flag;
278 * o and then we budgeted for it for the second time at the
279 * very beginning of this function.
280 *
281 * So what we have to do is to release the page budget we
282 * allocated.
283 */
284 release_new_page_budget(c);
285 else if (!PageChecked(page))
286 /*
287 * We are changing a page which already exists on the media.
288 * This means that changing the page does not make the amount
289 * of indexing information larger, and this part of the budget
290 * which we have already acquired may be released.
291 */
292 ubifs_convert_page_budget(c);
293
294 if (appending) {
295 struct ubifs_inode *ui = ubifs_inode(inode);
296
297 /*
298 * 'ubifs_write_end()' is optimized from the fast-path part of
299 * 'ubifs_write_begin()' and expects the @ui_mutex to be locked
300 * if data is appended.
301 */
302 mutex_lock(&ui->ui_mutex);
303 if (ui->dirty)
304 /*
305 * The inode is dirty already, so we may free the
306 * budget we allocated.
307 */
308 ubifs_release_dirty_inode_budget(c, ui);
309 }
310
311 *pagep = page;
312 return 0;
313}
314
315/**
316 * allocate_budget - allocate budget for 'ubifs_write_begin()'.
317 * @c: UBIFS file-system description object
318 * @page: page to allocate budget for
319 * @ui: UBIFS inode object the page belongs to
320 * @appending: non-zero if the page is appended
321 *
322 * This is a helper function for 'ubifs_write_begin()' which allocates budget
323 * for the operation. The budget is allocated differently depending on whether
324 * this is appending, whether the page is dirty or not, and so on. This
325 * function leaves the @ui->ui_mutex locked in case of appending. Returns zero
326 * in case of success and %-ENOSPC in case of failure.
327 */
328static int allocate_budget(struct ubifs_info *c, struct page *page,
329 struct ubifs_inode *ui, int appending)
330{
331 struct ubifs_budget_req req = { .fast = 1 };
332
333 if (PagePrivate(page)) {
334 if (!appending)
335 /*
336 * The page is dirty and we are not appending, which
337 * means no budget is needed at all.
338 */
339 return 0;
340
341 mutex_lock(&ui->ui_mutex);
342 if (ui->dirty)
343 /*
344 * The page is dirty and we are appending, so the inode
345 * has to be marked as dirty. However, it is already
346 * dirty, so we do not need any budget. We may return,
347 * but @ui->ui_mutex hast to be left locked because we
348 * should prevent write-back from flushing the inode
349 * and freeing the budget. The lock will be released in
350 * 'ubifs_write_end()'.
351 */
352 return 0;
353
354 /*
355 * The page is dirty, we are appending, the inode is clean, so
356 * we need to budget the inode change.
357 */
358 req.dirtied_ino = 1;
359 } else {
360 if (PageChecked(page))
361 /*
362 * The page corresponds to a hole and does not
363 * exist on the media. So changing it makes
364 * make the amount of indexing information
365 * larger, and we have to budget for a new
366 * page.
367 */
368 req.new_page = 1;
369 else
370 /*
371 * Not a hole, the change will not add any new
372 * indexing information, budget for page
373 * change.
374 */
375 req.dirtied_page = 1;
376
377 if (appending) {
378 mutex_lock(&ui->ui_mutex);
379 if (!ui->dirty)
380 /*
381 * The inode is clean but we will have to mark
382 * it as dirty because we are appending. This
383 * needs a budget.
384 */
385 req.dirtied_ino = 1;
386 }
387 }
388
389 return ubifs_budget_space(c, &req);
390}
391
392/*
393 * This function is called when a page of data is going to be written. Since
394 * the page of data will not necessarily go to the flash straight away, UBIFS
395 * has to reserve space on the media for it, which is done by means of
396 * budgeting.
397 *
398 * This is the hot-path of the file-system and we are trying to optimize it as
399 * much as possible. For this reasons it is split on 2 parts - slow and fast.
400 *
401 * There many budgeting cases:
402 * o a new page is appended - we have to budget for a new page and for
403 * changing the inode; however, if the inode is already dirty, there is
404 * no need to budget for it;
405 * o an existing clean page is changed - we have budget for it; if the page
406 * does not exist on the media (a hole), we have to budget for a new
407 * page; otherwise, we may budget for changing an existing page; the
408 * difference between these cases is that changing an existing page does
409 * not introduce anything new to the FS indexing information, so it does
410 * not grow, and smaller budget is acquired in this case;
411 * o an existing dirty page is changed - no need to budget at all, because
412 * the page budget has been acquired by earlier, when the page has been
413 * marked dirty.
414 *
415 * UBIFS budgeting sub-system may force write-back if it thinks there is no
416 * space to reserve. This imposes some locking restrictions and makes it
417 * impossible to take into account the above cases, and makes it impossible to
418 * optimize budgeting.
419 *
420 * The solution for this is that the fast path of 'ubifs_write_begin()' assumes
421 * there is a plenty of flash space and the budget will be acquired quickly,
422 * without forcing write-back. The slow path does not make this assumption.
423 */
424static int ubifs_write_begin(struct file *file, struct address_space *mapping,
425 loff_t pos, unsigned len, unsigned flags,
426 struct page **pagep, void **fsdata)
427{
428 struct inode *inode = mapping->host;
429 struct ubifs_info *c = inode->i_sb->s_fs_info;
430 struct ubifs_inode *ui = ubifs_inode(inode);
431 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
432 int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
433 struct page *page;
434
435
436 ubifs_assert(ubifs_inode(inode)->ui_size == inode->i_size);
437
438 if (unlikely(c->ro_media))
439 return -EROFS;
440
441 /* Try out the fast-path part first */
Nick Piggin54566b22009-01-04 12:00:53 -0800442 page = grab_cache_page_write_begin(mapping, index, flags);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300443 if (unlikely(!page))
444 return -ENOMEM;
445
446 if (!PageUptodate(page)) {
447 /* The page is not loaded from the flash */
Artem Bityutskiy7bbe5b52008-12-09 11:02:51 -0500448 if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300449 /*
450 * We change whole page so no need to load it. But we
451 * have to set the @PG_checked flag to make the further
452 * code the page is new. This might be not true, but it
453 * is better to budget more that to read the page from
454 * the media.
455 */
456 SetPageChecked(page);
457 else {
458 err = do_readpage(page);
459 if (err) {
460 unlock_page(page);
461 page_cache_release(page);
462 return err;
463 }
464 }
465
466 SetPageUptodate(page);
467 ClearPageError(page);
468 }
469
470 err = allocate_budget(c, page, ui, appending);
471 if (unlikely(err)) {
472 ubifs_assert(err == -ENOSPC);
473 /*
474 * Budgeting failed which means it would have to force
475 * write-back but didn't, because we set the @fast flag in the
476 * request. Write-back cannot be done now, while we have the
477 * page locked, because it would deadlock. Unlock and free
478 * everything and fall-back to slow-path.
479 */
480 if (appending) {
481 ubifs_assert(mutex_is_locked(&ui->ui_mutex));
482 mutex_unlock(&ui->ui_mutex);
483 }
484 unlock_page(page);
485 page_cache_release(page);
486
Nick Piggin54566b22009-01-04 12:00:53 -0800487 return write_begin_slow(mapping, pos, len, pagep, flags);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300488 }
489
490 /*
491 * Whee, we aquired budgeting quickly - without involving
492 * garbage-collection, committing or forceing write-back. We return
493 * with @ui->ui_mutex locked if we are appending pages, and unlocked
494 * otherwise. This is an optimization (slightly hacky though).
495 */
496 *pagep = page;
497 return 0;
498
499}
500
501/**
502 * cancel_budget - cancel budget.
503 * @c: UBIFS file-system description object
504 * @page: page to cancel budget for
505 * @ui: UBIFS inode object the page belongs to
506 * @appending: non-zero if the page is appended
507 *
508 * This is a helper function for a page write operation. It unlocks the
509 * @ui->ui_mutex in case of appending.
510 */
511static void cancel_budget(struct ubifs_info *c, struct page *page,
512 struct ubifs_inode *ui, int appending)
513{
514 if (appending) {
515 if (!ui->dirty)
516 ubifs_release_dirty_inode_budget(c, ui);
517 mutex_unlock(&ui->ui_mutex);
518 }
519 if (!PagePrivate(page)) {
520 if (PageChecked(page))
521 release_new_page_budget(c);
522 else
523 release_existing_page_budget(c);
524 }
525}
526
527static int ubifs_write_end(struct file *file, struct address_space *mapping,
528 loff_t pos, unsigned len, unsigned copied,
529 struct page *page, void *fsdata)
530{
531 struct inode *inode = mapping->host;
532 struct ubifs_inode *ui = ubifs_inode(inode);
533 struct ubifs_info *c = inode->i_sb->s_fs_info;
534 loff_t end_pos = pos + len;
535 int appending = !!(end_pos > inode->i_size);
536
537 dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
538 inode->i_ino, pos, page->index, len, copied, inode->i_size);
539
540 if (unlikely(copied < len && len == PAGE_CACHE_SIZE)) {
541 /*
542 * VFS copied less data to the page that it intended and
543 * declared in its '->write_begin()' call via the @len
544 * argument. If the page was not up-to-date, and @len was
545 * @PAGE_CACHE_SIZE, the 'ubifs_write_begin()' function did
546 * not load it from the media (for optimization reasons). This
547 * means that part of the page contains garbage. So read the
548 * page now.
549 */
550 dbg_gen("copied %d instead of %d, read page and repeat",
551 copied, len);
552 cancel_budget(c, page, ui, appending);
553
554 /*
555 * Return 0 to force VFS to repeat the whole operation, or the
556 * error code if 'do_readpage()' failes.
557 */
558 copied = do_readpage(page);
559 goto out;
560 }
561
562 if (!PagePrivate(page)) {
563 SetPagePrivate(page);
564 atomic_long_inc(&c->dirty_pg_cnt);
565 __set_page_dirty_nobuffers(page);
566 }
567
568 if (appending) {
569 i_size_write(inode, end_pos);
570 ui->ui_size = end_pos;
571 /*
572 * Note, we do not set @I_DIRTY_PAGES (which means that the
573 * inode has dirty pages), this has been done in
574 * '__set_page_dirty_nobuffers()'.
575 */
576 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
577 ubifs_assert(mutex_is_locked(&ui->ui_mutex));
578 mutex_unlock(&ui->ui_mutex);
579 }
580
581out:
582 unlock_page(page);
583 page_cache_release(page);
584 return copied;
585}
586
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300587/**
588 * populate_page - copy data nodes into a page for bulk-read.
589 * @c: UBIFS file-system description object
590 * @page: page
591 * @bu: bulk-read information
592 * @n: next zbranch slot
593 *
594 * This function returns %0 on success and a negative error code on failure.
595 */
596static int populate_page(struct ubifs_info *c, struct page *page,
597 struct bu_info *bu, int *n)
598{
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300599 int i = 0, nn = *n, offs = bu->zbranch[0].offs, hole = 0, read = 0;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300600 struct inode *inode = page->mapping->host;
601 loff_t i_size = i_size_read(inode);
602 unsigned int page_block;
603 void *addr, *zaddr;
604 pgoff_t end_index;
605
606 dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
607 inode->i_ino, page->index, i_size, page->flags);
608
609 addr = zaddr = kmap(page);
610
Adrian Huntered382d52008-09-05 16:17:42 +0300611 end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300612 if (!i_size || page->index > end_index) {
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300613 hole = 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300614 memset(addr, 0, PAGE_CACHE_SIZE);
615 goto out_hole;
616 }
617
618 page_block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
619 while (1) {
620 int err, len, out_len, dlen;
621
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300622 if (nn >= bu->cnt) {
623 hole = 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300624 memset(addr, 0, UBIFS_BLOCK_SIZE);
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300625 } else if (key_block(c, &bu->zbranch[nn].key) == page_block) {
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300626 struct ubifs_data_node *dn;
627
628 dn = bu->buf + (bu->zbranch[nn].offs - offs);
629
Harvey Harrison0ecb9522008-10-24 10:52:57 -0700630 ubifs_assert(le64_to_cpu(dn->ch.sqnum) >
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300631 ubifs_inode(inode)->creat_sqnum);
632
633 len = le32_to_cpu(dn->size);
634 if (len <= 0 || len > UBIFS_BLOCK_SIZE)
635 goto out_err;
636
637 dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
638 out_len = UBIFS_BLOCK_SIZE;
639 err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
640 le16_to_cpu(dn->compr_type));
641 if (err || len != out_len)
642 goto out_err;
643
644 if (len < UBIFS_BLOCK_SIZE)
645 memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
646
647 nn += 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300648 read = (i << UBIFS_BLOCK_SHIFT) + len;
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300649 } else if (key_block(c, &bu->zbranch[nn].key) < page_block) {
650 nn += 1;
651 continue;
652 } else {
653 hole = 1;
654 memset(addr, 0, UBIFS_BLOCK_SIZE);
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300655 }
656 if (++i >= UBIFS_BLOCKS_PER_PAGE)
657 break;
658 addr += UBIFS_BLOCK_SIZE;
659 page_block += 1;
660 }
661
662 if (end_index == page->index) {
663 int len = i_size & (PAGE_CACHE_SIZE - 1);
664
Adrian Huntered382d52008-09-05 16:17:42 +0300665 if (len && len < read)
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300666 memset(zaddr + len, 0, read - len);
667 }
668
669out_hole:
670 if (hole) {
671 SetPageChecked(page);
672 dbg_gen("hole");
673 }
674
675 SetPageUptodate(page);
676 ClearPageError(page);
677 flush_dcache_page(page);
678 kunmap(page);
679 *n = nn;
680 return 0;
681
682out_err:
683 ClearPageUptodate(page);
684 SetPageError(page);
685 flush_dcache_page(page);
686 kunmap(page);
687 ubifs_err("bad data node (block %u, inode %lu)",
688 page_block, inode->i_ino);
689 return -EINVAL;
690}
691
692/**
693 * ubifs_do_bulk_read - do bulk-read.
694 * @c: UBIFS file-system description object
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200695 * @bu: bulk-read information
696 * @page1: first page to read
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300697 *
698 * This function returns %1 if the bulk-read is done, otherwise %0 is returned.
699 */
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200700static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
701 struct page *page1)
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300702{
703 pgoff_t offset = page1->index, end_index;
704 struct address_space *mapping = page1->mapping;
705 struct inode *inode = mapping->host;
706 struct ubifs_inode *ui = ubifs_inode(inode);
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300707 int err, page_idx, page_cnt, ret = 0, n = 0;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200708 int allocate = bu->buf ? 0 : 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300709 loff_t isize;
710
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300711 err = ubifs_tnc_get_bu_keys(c, bu);
712 if (err)
713 goto out_warn;
714
715 if (bu->eof) {
716 /* Turn off bulk-read at the end of the file */
717 ui->read_in_a_row = 1;
718 ui->bulk_read = 0;
719 }
720
721 page_cnt = bu->blk_cnt >> UBIFS_BLOCKS_PER_PAGE_SHIFT;
722 if (!page_cnt) {
723 /*
724 * This happens when there are multiple blocks per page and the
725 * blocks for the first page we are looking for, are not
726 * together. If all the pages were like this, bulk-read would
727 * reduce performance, so we turn it off for a while.
728 */
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200729 goto out_bu_off;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300730 }
731
732 if (bu->cnt) {
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200733 if (allocate) {
734 /*
735 * Allocate bulk-read buffer depending on how many data
736 * nodes we are going to read.
737 */
738 bu->buf_len = bu->zbranch[bu->cnt - 1].offs +
739 bu->zbranch[bu->cnt - 1].len -
740 bu->zbranch[0].offs;
741 ubifs_assert(bu->buf_len > 0);
742 ubifs_assert(bu->buf_len <= c->leb_size);
743 bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN);
744 if (!bu->buf)
745 goto out_bu_off;
746 }
747
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300748 err = ubifs_tnc_bulk_read(c, bu);
749 if (err)
750 goto out_warn;
751 }
752
753 err = populate_page(c, page1, bu, &n);
754 if (err)
755 goto out_warn;
756
757 unlock_page(page1);
758 ret = 1;
759
760 isize = i_size_read(inode);
761 if (isize == 0)
762 goto out_free;
763 end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
764
765 for (page_idx = 1; page_idx < page_cnt; page_idx++) {
766 pgoff_t page_offset = offset + page_idx;
767 struct page *page;
768
769 if (page_offset > end_index)
770 break;
771 page = find_or_create_page(mapping, page_offset,
772 GFP_NOFS | __GFP_COLD);
773 if (!page)
774 break;
775 if (!PageUptodate(page))
776 err = populate_page(c, page, bu, &n);
777 unlock_page(page);
778 page_cache_release(page);
779 if (err)
780 break;
781 }
782
783 ui->last_page_read = offset + page_idx - 1;
784
785out_free:
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200786 if (allocate)
787 kfree(bu->buf);
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300788 return ret;
789
790out_warn:
791 ubifs_warn("ignoring error %d and skipping bulk-read", err);
792 goto out_free;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200793
794out_bu_off:
795 ui->read_in_a_row = ui->bulk_read = 0;
796 goto out_free;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300797}
798
799/**
800 * ubifs_bulk_read - determine whether to bulk-read and, if so, do it.
801 * @page: page from which to start bulk-read.
802 *
803 * Some flash media are capable of reading sequentially at faster rates. UBIFS
804 * bulk-read facility is designed to take advantage of that, by reading in one
805 * go consecutive data nodes that are also located consecutively in the same
806 * LEB. This function returns %1 if a bulk-read is done and %0 otherwise.
807 */
808static int ubifs_bulk_read(struct page *page)
809{
810 struct inode *inode = page->mapping->host;
811 struct ubifs_info *c = inode->i_sb->s_fs_info;
812 struct ubifs_inode *ui = ubifs_inode(inode);
813 pgoff_t index = page->index, last_page_read = ui->last_page_read;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200814 struct bu_info *bu;
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200815 int err = 0, allocated = 0;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300816
817 ui->last_page_read = index;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300818 if (!c->bulk_read)
819 return 0;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200820
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300821 /*
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200822 * Bulk-read is protected by @ui->ui_mutex, but it is an optimization,
823 * so don't bother if we cannot lock the mutex.
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300824 */
825 if (!mutex_trylock(&ui->ui_mutex))
826 return 0;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200827
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300828 if (index != last_page_read + 1) {
829 /* Turn off bulk-read if we stop reading sequentially */
830 ui->read_in_a_row = 1;
831 if (ui->bulk_read)
832 ui->bulk_read = 0;
833 goto out_unlock;
834 }
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200835
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300836 if (!ui->bulk_read) {
837 ui->read_in_a_row += 1;
838 if (ui->read_in_a_row < 3)
839 goto out_unlock;
840 /* Three reads in a row, so switch on bulk-read */
841 ui->bulk_read = 1;
842 }
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200843
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200844 /*
845 * If possible, try to use pre-allocated bulk-read information, which
846 * is protected by @c->bu_mutex.
847 */
848 if (mutex_trylock(&c->bu_mutex))
849 bu = &c->bu;
850 else {
851 bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN);
852 if (!bu)
853 goto out_unlock;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200854
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200855 bu->buf = NULL;
856 allocated = 1;
857 }
858
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200859 bu->buf_len = c->max_bu_buf_len;
860 data_key_init(c, &bu->key, inode->i_ino,
861 page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT);
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200862 err = ubifs_do_bulk_read(c, bu, page);
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200863
864 if (!allocated)
865 mutex_unlock(&c->bu_mutex);
866 else
867 kfree(bu);
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200868
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300869out_unlock:
870 mutex_unlock(&ui->ui_mutex);
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200871 return err;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300872}
873
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300874static int ubifs_readpage(struct file *file, struct page *page)
875{
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300876 if (ubifs_bulk_read(page))
877 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300878 do_readpage(page);
879 unlock_page(page);
880 return 0;
881}
882
883static int do_writepage(struct page *page, int len)
884{
885 int err = 0, i, blen;
886 unsigned int block;
887 void *addr;
888 union ubifs_key key;
889 struct inode *inode = page->mapping->host;
890 struct ubifs_info *c = inode->i_sb->s_fs_info;
891
892#ifdef UBIFS_DEBUG
893 spin_lock(&ui->ui_lock);
894 ubifs_assert(page->index <= ui->synced_i_size << PAGE_CACHE_SIZE);
895 spin_unlock(&ui->ui_lock);
896#endif
897
898 /* Update radix tree tags */
899 set_page_writeback(page);
900
901 addr = kmap(page);
902 block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
903 i = 0;
904 while (len) {
905 blen = min_t(int, len, UBIFS_BLOCK_SIZE);
906 data_key_init(c, &key, inode->i_ino, block);
907 err = ubifs_jnl_write_data(c, inode, &key, addr, blen);
908 if (err)
909 break;
910 if (++i >= UBIFS_BLOCKS_PER_PAGE)
911 break;
912 block += 1;
913 addr += blen;
914 len -= blen;
915 }
916 if (err) {
917 SetPageError(page);
918 ubifs_err("cannot write page %lu of inode %lu, error %d",
919 page->index, inode->i_ino, err);
920 ubifs_ro_mode(c, err);
921 }
922
923 ubifs_assert(PagePrivate(page));
924 if (PageChecked(page))
925 release_new_page_budget(c);
926 else
927 release_existing_page_budget(c);
928
929 atomic_long_dec(&c->dirty_pg_cnt);
930 ClearPagePrivate(page);
931 ClearPageChecked(page);
932
933 kunmap(page);
934 unlock_page(page);
935 end_page_writeback(page);
936 return err;
937}
938
939/*
940 * When writing-back dirty inodes, VFS first writes-back pages belonging to the
941 * inode, then the inode itself. For UBIFS this may cause a problem. Consider a
942 * situation when a we have an inode with size 0, then a megabyte of data is
943 * appended to the inode, then write-back starts and flushes some amount of the
944 * dirty pages, the journal becomes full, commit happens and finishes, and then
945 * an unclean reboot happens. When the file system is mounted next time, the
946 * inode size would still be 0, but there would be many pages which are beyond
947 * the inode size, they would be indexed and consume flash space. Because the
948 * journal has been committed, the replay would not be able to detect this
949 * situation and correct the inode size. This means UBIFS would have to scan
950 * whole index and correct all inode sizes, which is long an unacceptable.
951 *
952 * To prevent situations like this, UBIFS writes pages back only if they are
953 * within last synchronized inode size, i.e. the the size which has been
954 * written to the flash media last time. Otherwise, UBIFS forces inode
955 * write-back, thus making sure the on-flash inode contains current inode size,
956 * and then keeps writing pages back.
957 *
958 * Some locking issues explanation. 'ubifs_writepage()' first is called with
959 * the page locked, and it locks @ui_mutex. However, write-back does take inode
960 * @i_mutex, which means other VFS operations may be run on this inode at the
961 * same time. And the problematic one is truncation to smaller size, from where
962 * we have to call 'vmtruncate()', which first changes @inode->i_size, then
963 * drops the truncated pages. And while dropping the pages, it takes the page
964 * lock. This means that 'do_truncation()' cannot call 'vmtruncate()' with
965 * @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. This
966 * means that @inode->i_size is changed while @ui_mutex is unlocked.
967 *
968 * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond
969 * inode size. How do we do this if @inode->i_size may became smaller while we
970 * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the
971 * @ui->ui_isize "shadow" field which UBIFS uses instead of @inode->i_size
972 * internally and updates it under @ui_mutex.
973 *
974 * Q: why we do not worry that if we race with truncation, we may end up with a
975 * situation when the inode is truncated while we are in the middle of
976 * 'do_writepage()', so we do write beyond inode size?
977 * A: If we are in the middle of 'do_writepage()', truncation would be locked
978 * on the page lock and it would not write the truncated inode node to the
979 * journal before we have finished.
980 */
981static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
982{
983 struct inode *inode = page->mapping->host;
984 struct ubifs_inode *ui = ubifs_inode(inode);
985 loff_t i_size = i_size_read(inode), synced_i_size;
986 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
987 int err, len = i_size & (PAGE_CACHE_SIZE - 1);
988 void *kaddr;
989
990 dbg_gen("ino %lu, pg %lu, pg flags %#lx",
991 inode->i_ino, page->index, page->flags);
992 ubifs_assert(PagePrivate(page));
993
994 /* Is the page fully outside @i_size? (truncate in progress) */
995 if (page->index > end_index || (page->index == end_index && !len)) {
996 err = 0;
997 goto out_unlock;
998 }
999
1000 spin_lock(&ui->ui_lock);
1001 synced_i_size = ui->synced_i_size;
1002 spin_unlock(&ui->ui_lock);
1003
1004 /* Is the page fully inside @i_size? */
1005 if (page->index < end_index) {
1006 if (page->index >= synced_i_size >> PAGE_CACHE_SHIFT) {
1007 err = inode->i_sb->s_op->write_inode(inode, 1);
1008 if (err)
1009 goto out_unlock;
1010 /*
1011 * The inode has been written, but the write-buffer has
1012 * not been synchronized, so in case of an unclean
1013 * reboot we may end up with some pages beyond inode
1014 * size, but they would be in the journal (because
1015 * commit flushes write buffers) and recovery would deal
1016 * with this.
1017 */
1018 }
1019 return do_writepage(page, PAGE_CACHE_SIZE);
1020 }
1021
1022 /*
1023 * The page straddles @i_size. It must be zeroed out on each and every
1024 * writepage invocation because it may be mmapped. "A file is mapped
1025 * in multiples of the page size. For a file that is not a multiple of
1026 * the page size, the remaining memory is zeroed when mapped, and
1027 * writes to that region are not written out to the file."
1028 */
1029 kaddr = kmap_atomic(page, KM_USER0);
1030 memset(kaddr + len, 0, PAGE_CACHE_SIZE - len);
1031 flush_dcache_page(page);
1032 kunmap_atomic(kaddr, KM_USER0);
1033
1034 if (i_size > synced_i_size) {
1035 err = inode->i_sb->s_op->write_inode(inode, 1);
1036 if (err)
1037 goto out_unlock;
1038 }
1039
1040 return do_writepage(page, len);
1041
1042out_unlock:
1043 unlock_page(page);
1044 return err;
1045}
1046
1047/**
1048 * do_attr_changes - change inode attributes.
1049 * @inode: inode to change attributes for
1050 * @attr: describes attributes to change
1051 */
1052static void do_attr_changes(struct inode *inode, const struct iattr *attr)
1053{
1054 if (attr->ia_valid & ATTR_UID)
1055 inode->i_uid = attr->ia_uid;
1056 if (attr->ia_valid & ATTR_GID)
1057 inode->i_gid = attr->ia_gid;
1058 if (attr->ia_valid & ATTR_ATIME)
1059 inode->i_atime = timespec_trunc(attr->ia_atime,
1060 inode->i_sb->s_time_gran);
1061 if (attr->ia_valid & ATTR_MTIME)
1062 inode->i_mtime = timespec_trunc(attr->ia_mtime,
1063 inode->i_sb->s_time_gran);
1064 if (attr->ia_valid & ATTR_CTIME)
1065 inode->i_ctime = timespec_trunc(attr->ia_ctime,
1066 inode->i_sb->s_time_gran);
1067 if (attr->ia_valid & ATTR_MODE) {
1068 umode_t mode = attr->ia_mode;
1069
1070 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
1071 mode &= ~S_ISGID;
1072 inode->i_mode = mode;
1073 }
1074}
1075
1076/**
1077 * do_truncation - truncate an inode.
1078 * @c: UBIFS file-system description object
1079 * @inode: inode to truncate
1080 * @attr: inode attribute changes description
1081 *
1082 * This function implements VFS '->setattr()' call when the inode is truncated
1083 * to a smaller size. Returns zero in case of success and a negative error code
1084 * in case of failure.
1085 */
1086static int do_truncation(struct ubifs_info *c, struct inode *inode,
1087 const struct iattr *attr)
1088{
1089 int err;
1090 struct ubifs_budget_req req;
1091 loff_t old_size = inode->i_size, new_size = attr->ia_size;
Artem Bityutskiy04da11b2008-08-20 17:16:34 +03001092 int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001093 struct ubifs_inode *ui = ubifs_inode(inode);
1094
1095 dbg_gen("ino %lu, size %lld -> %lld", inode->i_ino, old_size, new_size);
1096 memset(&req, 0, sizeof(struct ubifs_budget_req));
1097
1098 /*
1099 * If this is truncation to a smaller size, and we do not truncate on a
1100 * block boundary, budget for changing one data block, because the last
1101 * block will be re-written.
1102 */
1103 if (new_size & (UBIFS_BLOCK_SIZE - 1))
1104 req.dirtied_page = 1;
1105
1106 req.dirtied_ino = 1;
1107 /* A funny way to budget for truncation node */
1108 req.dirtied_ino_d = UBIFS_TRUN_NODE_SZ;
1109 err = ubifs_budget_space(c, &req);
Artem Bityutskiy04da11b2008-08-20 17:16:34 +03001110 if (err) {
1111 /*
1112 * Treat truncations to zero as deletion and always allow them,
1113 * just like we do for '->unlink()'.
1114 */
1115 if (new_size || err != -ENOSPC)
1116 return err;
1117 budgeted = 0;
1118 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001119
1120 err = vmtruncate(inode, new_size);
1121 if (err)
1122 goto out_budg;
1123
1124 if (offset) {
1125 pgoff_t index = new_size >> PAGE_CACHE_SHIFT;
1126 struct page *page;
1127
1128 page = find_lock_page(inode->i_mapping, index);
1129 if (page) {
1130 if (PageDirty(page)) {
1131 /*
1132 * 'ubifs_jnl_truncate()' will try to truncate
1133 * the last data node, but it contains
1134 * out-of-date data because the page is dirty.
1135 * Write the page now, so that
1136 * 'ubifs_jnl_truncate()' will see an already
1137 * truncated (and up to date) data node.
1138 */
1139 ubifs_assert(PagePrivate(page));
1140
1141 clear_page_dirty_for_io(page);
1142 if (UBIFS_BLOCKS_PER_PAGE_SHIFT)
1143 offset = new_size &
1144 (PAGE_CACHE_SIZE - 1);
1145 err = do_writepage(page, offset);
1146 page_cache_release(page);
1147 if (err)
1148 goto out_budg;
1149 /*
1150 * We could now tell 'ubifs_jnl_truncate()' not
1151 * to read the last block.
1152 */
1153 } else {
1154 /*
1155 * We could 'kmap()' the page and pass the data
1156 * to 'ubifs_jnl_truncate()' to save it from
1157 * having to read it.
1158 */
1159 unlock_page(page);
1160 page_cache_release(page);
1161 }
1162 }
1163 }
1164
1165 mutex_lock(&ui->ui_mutex);
1166 ui->ui_size = inode->i_size;
1167 /* Truncation changes inode [mc]time */
1168 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1169 /* The other attributes may be changed at the same time as well */
1170 do_attr_changes(inode, attr);
1171
1172 err = ubifs_jnl_truncate(c, inode, old_size, new_size);
1173 mutex_unlock(&ui->ui_mutex);
1174out_budg:
Artem Bityutskiy04da11b2008-08-20 17:16:34 +03001175 if (budgeted)
1176 ubifs_release_budget(c, &req);
1177 else {
1178 c->nospace = c->nospace_rp = 0;
1179 smp_wmb();
1180 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001181 return err;
1182}
1183
1184/**
1185 * do_setattr - change inode attributes.
1186 * @c: UBIFS file-system description object
1187 * @inode: inode to change attributes for
1188 * @attr: inode attribute changes description
1189 *
1190 * This function implements VFS '->setattr()' call for all cases except
1191 * truncations to smaller size. Returns zero in case of success and a negative
1192 * error code in case of failure.
1193 */
1194static int do_setattr(struct ubifs_info *c, struct inode *inode,
1195 const struct iattr *attr)
1196{
1197 int err, release;
1198 loff_t new_size = attr->ia_size;
1199 struct ubifs_inode *ui = ubifs_inode(inode);
1200 struct ubifs_budget_req req = { .dirtied_ino = 1,
Artem Bityutskiydab4b4d2008-07-24 14:52:45 +03001201 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001202
1203 err = ubifs_budget_space(c, &req);
1204 if (err)
1205 return err;
1206
1207 if (attr->ia_valid & ATTR_SIZE) {
1208 dbg_gen("size %lld -> %lld", inode->i_size, new_size);
1209 err = vmtruncate(inode, new_size);
1210 if (err)
1211 goto out;
1212 }
1213
1214 mutex_lock(&ui->ui_mutex);
1215 if (attr->ia_valid & ATTR_SIZE) {
1216 /* Truncation changes inode [mc]time */
1217 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1218 /* 'vmtruncate()' changed @i_size, update @ui_size */
1219 ui->ui_size = inode->i_size;
1220 }
1221
1222 do_attr_changes(inode, attr);
1223
1224 release = ui->dirty;
1225 if (attr->ia_valid & ATTR_SIZE)
1226 /*
1227 * Inode length changed, so we have to make sure
1228 * @I_DIRTY_DATASYNC is set.
1229 */
1230 __mark_inode_dirty(inode, I_DIRTY_SYNC | I_DIRTY_DATASYNC);
1231 else
1232 mark_inode_dirty_sync(inode);
1233 mutex_unlock(&ui->ui_mutex);
1234
1235 if (release)
1236 ubifs_release_budget(c, &req);
1237 if (IS_SYNC(inode))
1238 err = inode->i_sb->s_op->write_inode(inode, 1);
1239 return err;
1240
1241out:
1242 ubifs_release_budget(c, &req);
1243 return err;
1244}
1245
1246int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
1247{
1248 int err;
1249 struct inode *inode = dentry->d_inode;
1250 struct ubifs_info *c = inode->i_sb->s_fs_info;
1251
Artem Bityutskiy7d32c2b2008-07-18 18:54:29 +03001252 dbg_gen("ino %lu, mode %#x, ia_valid %#x",
1253 inode->i_ino, inode->i_mode, attr->ia_valid);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001254 err = inode_change_ok(inode, attr);
1255 if (err)
1256 return err;
1257
1258 err = dbg_check_synced_i_size(inode);
1259 if (err)
1260 return err;
1261
1262 if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size < inode->i_size)
1263 /* Truncation to a smaller size */
1264 err = do_truncation(c, inode, attr);
1265 else
1266 err = do_setattr(c, inode, attr);
1267
1268 return err;
1269}
1270
1271static void ubifs_invalidatepage(struct page *page, unsigned long offset)
1272{
1273 struct inode *inode = page->mapping->host;
1274 struct ubifs_info *c = inode->i_sb->s_fs_info;
1275
1276 ubifs_assert(PagePrivate(page));
1277 if (offset)
1278 /* Partial page remains dirty */
1279 return;
1280
1281 if (PageChecked(page))
1282 release_new_page_budget(c);
1283 else
1284 release_existing_page_budget(c);
1285
1286 atomic_long_dec(&c->dirty_pg_cnt);
1287 ClearPagePrivate(page);
1288 ClearPageChecked(page);
1289}
1290
1291static void *ubifs_follow_link(struct dentry *dentry, struct nameidata *nd)
1292{
1293 struct ubifs_inode *ui = ubifs_inode(dentry->d_inode);
1294
1295 nd_set_link(nd, ui->data);
1296 return NULL;
1297}
1298
1299int ubifs_fsync(struct file *file, struct dentry *dentry, int datasync)
1300{
1301 struct inode *inode = dentry->d_inode;
1302 struct ubifs_info *c = inode->i_sb->s_fs_info;
1303 int err;
1304
1305 dbg_gen("syncing inode %lu", inode->i_ino);
1306
1307 /*
1308 * VFS has already synchronized dirty pages for this inode. Synchronize
1309 * the inode unless this is a 'datasync()' call.
1310 */
1311 if (!datasync || (inode->i_state & I_DIRTY_DATASYNC)) {
1312 err = inode->i_sb->s_op->write_inode(inode, 1);
1313 if (err)
1314 return err;
1315 }
1316
1317 /*
1318 * Nodes related to this inode may still sit in a write-buffer. Flush
1319 * them.
1320 */
1321 err = ubifs_sync_wbufs_by_inode(c, inode);
1322 if (err)
1323 return err;
1324
1325 return 0;
1326}
1327
1328/**
1329 * mctime_update_needed - check if mtime or ctime update is needed.
1330 * @inode: the inode to do the check for
1331 * @now: current time
1332 *
1333 * This helper function checks if the inode mtime/ctime should be updated or
1334 * not. If current values of the time-stamps are within the UBIFS inode time
1335 * granularity, they are not updated. This is an optimization.
1336 */
1337static inline int mctime_update_needed(const struct inode *inode,
1338 const struct timespec *now)
1339{
1340 if (!timespec_equal(&inode->i_mtime, now) ||
1341 !timespec_equal(&inode->i_ctime, now))
1342 return 1;
1343 return 0;
1344}
1345
1346/**
1347 * update_ctime - update mtime and ctime of an inode.
1348 * @c: UBIFS file-system description object
1349 * @inode: inode to update
1350 *
1351 * This function updates mtime and ctime of the inode if it is not equivalent to
1352 * current time. Returns zero in case of success and a negative error code in
1353 * case of failure.
1354 */
1355static int update_mctime(struct ubifs_info *c, struct inode *inode)
1356{
1357 struct timespec now = ubifs_current_time(inode);
1358 struct ubifs_inode *ui = ubifs_inode(inode);
1359
1360 if (mctime_update_needed(inode, &now)) {
1361 int err, release;
1362 struct ubifs_budget_req req = { .dirtied_ino = 1,
Artem Bityutskiydab4b4d2008-07-24 14:52:45 +03001363 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001364
1365 err = ubifs_budget_space(c, &req);
1366 if (err)
1367 return err;
1368
1369 mutex_lock(&ui->ui_mutex);
1370 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1371 release = ui->dirty;
1372 mark_inode_dirty_sync(inode);
1373 mutex_unlock(&ui->ui_mutex);
1374 if (release)
1375 ubifs_release_budget(c, &req);
1376 }
1377
1378 return 0;
1379}
1380
1381static ssize_t ubifs_aio_write(struct kiocb *iocb, const struct iovec *iov,
1382 unsigned long nr_segs, loff_t pos)
1383{
1384 int err;
1385 ssize_t ret;
1386 struct inode *inode = iocb->ki_filp->f_mapping->host;
1387 struct ubifs_info *c = inode->i_sb->s_fs_info;
1388
1389 err = update_mctime(c, inode);
1390 if (err)
1391 return err;
1392
1393 ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
1394 if (ret < 0)
1395 return ret;
1396
1397 if (ret > 0 && (IS_SYNC(inode) || iocb->ki_filp->f_flags & O_SYNC)) {
1398 err = ubifs_sync_wbufs_by_inode(c, inode);
1399 if (err)
1400 return err;
1401 }
1402
1403 return ret;
1404}
1405
1406static int ubifs_set_page_dirty(struct page *page)
1407{
1408 int ret;
1409
1410 ret = __set_page_dirty_nobuffers(page);
1411 /*
1412 * An attempt to dirty a page without budgeting for it - should not
1413 * happen.
1414 */
1415 ubifs_assert(ret == 0);
1416 return ret;
1417}
1418
1419static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
1420{
1421 /*
1422 * An attempt to release a dirty page without budgeting for it - should
1423 * not happen.
1424 */
1425 if (PageWriteback(page))
1426 return 0;
1427 ubifs_assert(PagePrivate(page));
1428 ubifs_assert(0);
1429 ClearPagePrivate(page);
1430 ClearPageChecked(page);
1431 return 1;
1432}
1433
1434/*
1435 * mmap()d file has taken write protection fault and is being made
1436 * writable. UBIFS must ensure page is budgeted for.
1437 */
1438static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
1439{
1440 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
1441 struct ubifs_info *c = inode->i_sb->s_fs_info;
1442 struct timespec now = ubifs_current_time(inode);
1443 struct ubifs_budget_req req = { .new_page = 1 };
1444 int err, update_time;
1445
1446 dbg_gen("ino %lu, pg %lu, i_size %lld", inode->i_ino, page->index,
1447 i_size_read(inode));
1448 ubifs_assert(!(inode->i_sb->s_flags & MS_RDONLY));
1449
1450 if (unlikely(c->ro_media))
1451 return -EROFS;
1452
1453 /*
1454 * We have not locked @page so far so we may budget for changing the
1455 * page. Note, we cannot do this after we locked the page, because
1456 * budgeting may cause write-back which would cause deadlock.
1457 *
1458 * At the moment we do not know whether the page is dirty or not, so we
1459 * assume that it is not and budget for a new page. We could look at
1460 * the @PG_private flag and figure this out, but we may race with write
1461 * back and the page state may change by the time we lock it, so this
1462 * would need additional care. We do not bother with this at the
1463 * moment, although it might be good idea to do. Instead, we allocate
1464 * budget for a new page and amend it later on if the page was in fact
1465 * dirty.
1466 *
1467 * The budgeting-related logic of this function is similar to what we
1468 * do in 'ubifs_write_begin()' and 'ubifs_write_end()'. Glance there
1469 * for more comments.
1470 */
1471 update_time = mctime_update_needed(inode, &now);
1472 if (update_time)
1473 /*
1474 * We have to change inode time stamp which requires extra
1475 * budgeting.
1476 */
1477 req.dirtied_ino = 1;
1478
1479 err = ubifs_budget_space(c, &req);
1480 if (unlikely(err)) {
1481 if (err == -ENOSPC)
1482 ubifs_warn("out of space for mmapped file "
1483 "(inode number %lu)", inode->i_ino);
1484 return err;
1485 }
1486
1487 lock_page(page);
1488 if (unlikely(page->mapping != inode->i_mapping ||
1489 page_offset(page) > i_size_read(inode))) {
1490 /* Page got truncated out from underneath us */
1491 err = -EINVAL;
1492 goto out_unlock;
1493 }
1494
1495 if (PagePrivate(page))
1496 release_new_page_budget(c);
1497 else {
1498 if (!PageChecked(page))
1499 ubifs_convert_page_budget(c);
1500 SetPagePrivate(page);
1501 atomic_long_inc(&c->dirty_pg_cnt);
1502 __set_page_dirty_nobuffers(page);
1503 }
1504
1505 if (update_time) {
1506 int release;
1507 struct ubifs_inode *ui = ubifs_inode(inode);
1508
1509 mutex_lock(&ui->ui_mutex);
1510 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1511 release = ui->dirty;
1512 mark_inode_dirty_sync(inode);
1513 mutex_unlock(&ui->ui_mutex);
1514 if (release)
1515 ubifs_release_dirty_inode_budget(c, ui);
1516 }
1517
1518 unlock_page(page);
1519 return 0;
1520
1521out_unlock:
1522 unlock_page(page);
1523 ubifs_release_budget(c, &req);
1524 return err;
1525}
1526
1527static struct vm_operations_struct ubifs_file_vm_ops = {
1528 .fault = filemap_fault,
1529 .page_mkwrite = ubifs_vm_page_mkwrite,
1530};
1531
1532static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1533{
1534 int err;
1535
1536 /* 'generic_file_mmap()' takes care of NOMMU case */
1537 err = generic_file_mmap(file, vma);
1538 if (err)
1539 return err;
1540 vma->vm_ops = &ubifs_file_vm_ops;
1541 return 0;
1542}
1543
1544struct address_space_operations ubifs_file_address_operations = {
1545 .readpage = ubifs_readpage,
1546 .writepage = ubifs_writepage,
1547 .write_begin = ubifs_write_begin,
1548 .write_end = ubifs_write_end,
1549 .invalidatepage = ubifs_invalidatepage,
1550 .set_page_dirty = ubifs_set_page_dirty,
1551 .releasepage = ubifs_releasepage,
1552};
1553
1554struct inode_operations ubifs_file_inode_operations = {
1555 .setattr = ubifs_setattr,
1556 .getattr = ubifs_getattr,
1557#ifdef CONFIG_UBIFS_FS_XATTR
1558 .setxattr = ubifs_setxattr,
1559 .getxattr = ubifs_getxattr,
1560 .listxattr = ubifs_listxattr,
1561 .removexattr = ubifs_removexattr,
1562#endif
1563};
1564
1565struct inode_operations ubifs_symlink_inode_operations = {
1566 .readlink = generic_readlink,
1567 .follow_link = ubifs_follow_link,
1568 .setattr = ubifs_setattr,
1569 .getattr = ubifs_getattr,
1570};
1571
1572struct file_operations ubifs_file_operations = {
1573 .llseek = generic_file_llseek,
1574 .read = do_sync_read,
1575 .write = do_sync_write,
1576 .aio_read = generic_file_aio_read,
1577 .aio_write = ubifs_aio_write,
1578 .mmap = ubifs_file_mmap,
1579 .fsync = ubifs_fsync,
1580 .unlocked_ioctl = ubifs_ioctl,
1581 .splice_read = generic_file_splice_read,
Zoltan Sogor22bc7fa2008-07-28 16:28:49 +02001582 .splice_write = generic_file_splice_write,
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001583#ifdef CONFIG_COMPAT
1584 .compat_ioctl = ubifs_compat_ioctl,
1585#endif
1586};