blob: 03ae894c45dea3a04181a20cb3c5b123bac083ce [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/*
Artem Bityutskiy873a64c2009-09-01 17:06:43 +030024 * This file implements VFS file and inode operations for regular files, device
Artem Bityutskiy1e517642008-07-14 19:08:37 +030025 * nodes and symlinks as well as address space operations.
26 *
Artem Bityutskiy873a64c2009-09-01 17:06:43 +030027 * UBIFS uses 2 page flags: @PG_private and @PG_checked. @PG_private is set if
28 * the page is dirty and is used for optimization purposes - dirty pages are
29 * not budgeted so the flag shows that 'ubifs_write_end()' should not release
30 * the budget for this page. The @PG_checked flag is set if full budgeting is
31 * required for the page e.g., when it corresponds to a file hole or it is
32 * beyond the file size. The budgeting is done in 'ubifs_write_begin()', because
33 * it is OK to fail in this function, and the budget is released in
34 * 'ubifs_write_end()'. So the @PG_private and @PG_checked flags carry
35 * information about how the page was budgeted, to make it possible to release
36 * the budget properly.
Artem Bityutskiy1e517642008-07-14 19:08:37 +030037 *
Artem Bityutskiy873a64c2009-09-01 17:06:43 +030038 * A thing to keep in mind: inode @i_mutex is locked in most VFS operations we
39 * implement. However, this is not true for 'ubifs_writepage()', which may be
40 * called with @i_mutex unlocked. For example, when pdflush is doing background
41 * write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex. At "normal"
42 * work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g. in the
43 * "sys_write -> alloc_pages -> direct reclaim path". So, in 'ubifs_writepage()'
44 * we are only guaranteed that the page is locked.
Artem Bityutskiy1e517642008-07-14 19:08:37 +030045 *
Artem Bityutskiy873a64c2009-09-01 17:06:43 +030046 * Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the
47 * read-ahead path does not lock it ("sys_read -> generic_file_aio_read ->
Christoph Hellwigeaff8072009-12-17 14:25:01 +010048 * ondemand_readahead -> readpage"). In case of readahead, @I_SYNC flag is not
Artem Bityutskiy873a64c2009-09-01 17:06:43 +030049 * set as well. However, UBIFS disables readahead.
Artem Bityutskiy1e517642008-07-14 19:08:37 +030050 */
51
52#include "ubifs.h"
53#include <linux/mount.h>
Al Viro3f8206d2008-07-26 03:46:43 -040054#include <linux/namei.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090055#include <linux/slab.h>
Artem Bityutskiy1e517642008-07-14 19:08:37 +030056
57static int read_block(struct inode *inode, void *addr, unsigned int block,
58 struct ubifs_data_node *dn)
59{
60 struct ubifs_info *c = inode->i_sb->s_fs_info;
61 int err, len, out_len;
62 union ubifs_key key;
63 unsigned int dlen;
64
65 data_key_init(c, &key, inode->i_ino, block);
66 err = ubifs_tnc_lookup(c, &key, dn);
67 if (err) {
68 if (err == -ENOENT)
69 /* Not found, so it must be a hole */
70 memset(addr, 0, UBIFS_BLOCK_SIZE);
71 return err;
72 }
73
Artem Bityutskiyf92b9822008-12-28 11:34:26 +020074 ubifs_assert(le64_to_cpu(dn->ch.sqnum) >
75 ubifs_inode(inode)->creat_sqnum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +030076 len = le32_to_cpu(dn->size);
77 if (len <= 0 || len > UBIFS_BLOCK_SIZE)
78 goto dump;
79
80 dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
81 out_len = UBIFS_BLOCK_SIZE;
82 err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
83 le16_to_cpu(dn->compr_type));
84 if (err || len != out_len)
85 goto dump;
86
87 /*
88 * Data length can be less than a full block, even for blocks that are
89 * not the last in the file (e.g., as a result of making a hole and
90 * appending data). Ensure that the remainder is zeroed out.
91 */
92 if (len < UBIFS_BLOCK_SIZE)
93 memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
94
95 return 0;
96
97dump:
98 ubifs_err("bad data node (block %u, inode %lu)",
99 block, inode->i_ino);
100 dbg_dump_node(c, dn);
101 return -EINVAL;
102}
103
104static int do_readpage(struct page *page)
105{
106 void *addr;
107 int err = 0, i;
108 unsigned int block, beyond;
109 struct ubifs_data_node *dn;
110 struct inode *inode = page->mapping->host;
111 loff_t i_size = i_size_read(inode);
112
113 dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
114 inode->i_ino, page->index, i_size, page->flags);
115 ubifs_assert(!PageChecked(page));
116 ubifs_assert(!PagePrivate(page));
117
118 addr = kmap(page);
119
120 block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
121 beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
122 if (block >= beyond) {
123 /* Reading beyond inode */
124 SetPageChecked(page);
125 memset(addr, 0, PAGE_CACHE_SIZE);
126 goto out;
127 }
128
129 dn = kmalloc(UBIFS_MAX_DATA_NODE_SZ, GFP_NOFS);
130 if (!dn) {
131 err = -ENOMEM;
132 goto error;
133 }
134
135 i = 0;
136 while (1) {
137 int ret;
138
139 if (block >= beyond) {
140 /* Reading beyond inode */
141 err = -ENOENT;
142 memset(addr, 0, UBIFS_BLOCK_SIZE);
143 } else {
144 ret = read_block(inode, addr, block, dn);
145 if (ret) {
146 err = ret;
147 if (err != -ENOENT)
148 break;
Adrian Huntered382d52008-09-05 16:17:42 +0300149 } else if (block + 1 == beyond) {
150 int dlen = le32_to_cpu(dn->size);
151 int ilen = i_size & (UBIFS_BLOCK_SIZE - 1);
152
153 if (ilen && ilen < dlen)
154 memset(addr + ilen, 0, dlen - ilen);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300155 }
156 }
157 if (++i >= UBIFS_BLOCKS_PER_PAGE)
158 break;
159 block += 1;
160 addr += UBIFS_BLOCK_SIZE;
161 }
162 if (err) {
163 if (err == -ENOENT) {
164 /* Not found, so it must be a hole */
165 SetPageChecked(page);
166 dbg_gen("hole");
167 goto out_free;
168 }
169 ubifs_err("cannot read page %lu of inode %lu, error %d",
170 page->index, inode->i_ino, err);
171 goto error;
172 }
173
174out_free:
175 kfree(dn);
176out:
177 SetPageUptodate(page);
178 ClearPageError(page);
179 flush_dcache_page(page);
180 kunmap(page);
181 return 0;
182
183error:
184 kfree(dn);
185 ClearPageUptodate(page);
186 SetPageError(page);
187 flush_dcache_page(page);
188 kunmap(page);
189 return err;
190}
191
192/**
193 * release_new_page_budget - release budget of a new page.
194 * @c: UBIFS file-system description object
195 *
196 * This is a helper function which releases budget corresponding to the budget
197 * of one new page of data.
198 */
199static void release_new_page_budget(struct ubifs_info *c)
200{
201 struct ubifs_budget_req req = { .recalculate = 1, .new_page = 1 };
202
203 ubifs_release_budget(c, &req);
204}
205
206/**
207 * release_existing_page_budget - release budget of an existing page.
208 * @c: UBIFS file-system description object
209 *
210 * This is a helper function which releases budget corresponding to the budget
211 * of changing one one page of data which already exists on the flash media.
212 */
213static void release_existing_page_budget(struct ubifs_info *c)
214{
215 struct ubifs_budget_req req = { .dd_growth = c->page_budget};
216
217 ubifs_release_budget(c, &req);
218}
219
220static int write_begin_slow(struct address_space *mapping,
Nick Piggin54566b22009-01-04 12:00:53 -0800221 loff_t pos, unsigned len, struct page **pagep,
222 unsigned flags)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300223{
224 struct inode *inode = mapping->host;
225 struct ubifs_info *c = inode->i_sb->s_fs_info;
226 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
227 struct ubifs_budget_req req = { .new_page = 1 };
228 int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
229 struct page *page;
230
231 dbg_gen("ino %lu, pos %llu, len %u, i_size %lld",
232 inode->i_ino, pos, len, inode->i_size);
233
234 /*
235 * At the slow path we have to budget before locking the page, because
236 * budgeting may force write-back, which would wait on locked pages and
237 * deadlock if we had the page locked. At this point we do not know
238 * anything about the page, so assume that this is a new page which is
239 * written to a hole. This corresponds to largest budget. Later the
240 * budget will be amended if this is not true.
241 */
242 if (appending)
243 /* We are appending data, budget for inode change */
244 req.dirtied_ino = 1;
245
246 err = ubifs_budget_space(c, &req);
247 if (unlikely(err))
248 return err;
249
Nick Piggin54566b22009-01-04 12:00:53 -0800250 page = grab_cache_page_write_begin(mapping, index, flags);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300251 if (unlikely(!page)) {
252 ubifs_release_budget(c, &req);
253 return -ENOMEM;
254 }
255
256 if (!PageUptodate(page)) {
Artem Bityutskiy7bbe5b52008-12-09 11:02:51 -0500257 if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300258 SetPageChecked(page);
259 else {
260 err = do_readpage(page);
261 if (err) {
262 unlock_page(page);
263 page_cache_release(page);
264 return err;
265 }
266 }
267
268 SetPageUptodate(page);
269 ClearPageError(page);
270 }
271
272 if (PagePrivate(page))
273 /*
274 * The page is dirty, which means it was budgeted twice:
275 * o first time the budget was allocated by the task which
276 * made the page dirty and set the PG_private flag;
277 * o and then we budgeted for it for the second time at the
278 * very beginning of this function.
279 *
280 * So what we have to do is to release the page budget we
281 * allocated.
282 */
283 release_new_page_budget(c);
284 else if (!PageChecked(page))
285 /*
286 * We are changing a page which already exists on the media.
287 * This means that changing the page does not make the amount
288 * of indexing information larger, and this part of the budget
289 * which we have already acquired may be released.
290 */
291 ubifs_convert_page_budget(c);
292
293 if (appending) {
294 struct ubifs_inode *ui = ubifs_inode(inode);
295
296 /*
297 * 'ubifs_write_end()' is optimized from the fast-path part of
298 * 'ubifs_write_begin()' and expects the @ui_mutex to be locked
299 * if data is appended.
300 */
301 mutex_lock(&ui->ui_mutex);
302 if (ui->dirty)
303 /*
304 * The inode is dirty already, so we may free the
305 * budget we allocated.
306 */
307 ubifs_release_dirty_inode_budget(c, ui);
308 }
309
310 *pagep = page;
311 return 0;
312}
313
314/**
315 * allocate_budget - allocate budget for 'ubifs_write_begin()'.
316 * @c: UBIFS file-system description object
317 * @page: page to allocate budget for
318 * @ui: UBIFS inode object the page belongs to
319 * @appending: non-zero if the page is appended
320 *
321 * This is a helper function for 'ubifs_write_begin()' which allocates budget
322 * for the operation. The budget is allocated differently depending on whether
323 * this is appending, whether the page is dirty or not, and so on. This
324 * function leaves the @ui->ui_mutex locked in case of appending. Returns zero
325 * in case of success and %-ENOSPC in case of failure.
326 */
327static int allocate_budget(struct ubifs_info *c, struct page *page,
328 struct ubifs_inode *ui, int appending)
329{
330 struct ubifs_budget_req req = { .fast = 1 };
331
332 if (PagePrivate(page)) {
333 if (!appending)
334 /*
335 * The page is dirty and we are not appending, which
336 * means no budget is needed at all.
337 */
338 return 0;
339
340 mutex_lock(&ui->ui_mutex);
341 if (ui->dirty)
342 /*
343 * The page is dirty and we are appending, so the inode
344 * has to be marked as dirty. However, it is already
345 * dirty, so we do not need any budget. We may return,
346 * but @ui->ui_mutex hast to be left locked because we
347 * should prevent write-back from flushing the inode
348 * and freeing the budget. The lock will be released in
349 * 'ubifs_write_end()'.
350 */
351 return 0;
352
353 /*
354 * The page is dirty, we are appending, the inode is clean, so
355 * we need to budget the inode change.
356 */
357 req.dirtied_ino = 1;
358 } else {
359 if (PageChecked(page))
360 /*
361 * The page corresponds to a hole and does not
362 * exist on the media. So changing it makes
363 * make the amount of indexing information
364 * larger, and we have to budget for a new
365 * page.
366 */
367 req.new_page = 1;
368 else
369 /*
370 * Not a hole, the change will not add any new
371 * indexing information, budget for page
372 * change.
373 */
374 req.dirtied_page = 1;
375
376 if (appending) {
377 mutex_lock(&ui->ui_mutex);
378 if (!ui->dirty)
379 /*
380 * The inode is clean but we will have to mark
381 * it as dirty because we are appending. This
382 * needs a budget.
383 */
384 req.dirtied_ino = 1;
385 }
386 }
387
388 return ubifs_budget_space(c, &req);
389}
390
391/*
392 * This function is called when a page of data is going to be written. Since
393 * the page of data will not necessarily go to the flash straight away, UBIFS
394 * has to reserve space on the media for it, which is done by means of
395 * budgeting.
396 *
397 * This is the hot-path of the file-system and we are trying to optimize it as
398 * much as possible. For this reasons it is split on 2 parts - slow and fast.
399 *
400 * There many budgeting cases:
401 * o a new page is appended - we have to budget for a new page and for
402 * changing the inode; however, if the inode is already dirty, there is
403 * no need to budget for it;
404 * o an existing clean page is changed - we have budget for it; if the page
405 * does not exist on the media (a hole), we have to budget for a new
406 * page; otherwise, we may budget for changing an existing page; the
407 * difference between these cases is that changing an existing page does
408 * not introduce anything new to the FS indexing information, so it does
409 * not grow, and smaller budget is acquired in this case;
410 * o an existing dirty page is changed - no need to budget at all, because
411 * the page budget has been acquired by earlier, when the page has been
412 * marked dirty.
413 *
414 * UBIFS budgeting sub-system may force write-back if it thinks there is no
415 * space to reserve. This imposes some locking restrictions and makes it
416 * impossible to take into account the above cases, and makes it impossible to
417 * optimize budgeting.
418 *
419 * The solution for this is that the fast path of 'ubifs_write_begin()' assumes
420 * there is a plenty of flash space and the budget will be acquired quickly,
421 * without forcing write-back. The slow path does not make this assumption.
422 */
423static int ubifs_write_begin(struct file *file, struct address_space *mapping,
424 loff_t pos, unsigned len, unsigned flags,
425 struct page **pagep, void **fsdata)
426{
427 struct inode *inode = mapping->host;
428 struct ubifs_info *c = inode->i_sb->s_fs_info;
429 struct ubifs_inode *ui = ubifs_inode(inode);
430 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
431 int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
Adrian Hunterf55aa592009-02-23 12:47:25 +0200432 int skipped_read = 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300433 struct page *page;
434
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300435 ubifs_assert(ubifs_inode(inode)->ui_size == inode->i_size);
436
437 if (unlikely(c->ro_media))
438 return -EROFS;
439
440 /* Try out the fast-path part first */
Nick Piggin54566b22009-01-04 12:00:53 -0800441 page = grab_cache_page_write_begin(mapping, index, flags);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300442 if (unlikely(!page))
443 return -ENOMEM;
444
445 if (!PageUptodate(page)) {
446 /* The page is not loaded from the flash */
Adrian Hunterf55aa592009-02-23 12:47:25 +0200447 if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300448 /*
449 * We change whole page so no need to load it. But we
450 * have to set the @PG_checked flag to make the further
Artem Bityutskiy873a64c2009-09-01 17:06:43 +0300451 * code know that the page is new. This might be not
452 * true, but it is better to budget more than to read
453 * the page from the media.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300454 */
455 SetPageChecked(page);
Adrian Hunterf55aa592009-02-23 12:47:25 +0200456 skipped_read = 1;
457 } else {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300458 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 /*
Adrian Hunterf55aa592009-02-23 12:47:25 +0200474 * If we skipped reading the page because we were going to
475 * write all of it, then it is not up to date.
476 */
477 if (skipped_read) {
478 ClearPageChecked(page);
479 ClearPageUptodate(page);
480 }
481 /*
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300482 * Budgeting failed which means it would have to force
483 * write-back but didn't, because we set the @fast flag in the
484 * request. Write-back cannot be done now, while we have the
485 * page locked, because it would deadlock. Unlock and free
486 * everything and fall-back to slow-path.
487 */
488 if (appending) {
489 ubifs_assert(mutex_is_locked(&ui->ui_mutex));
490 mutex_unlock(&ui->ui_mutex);
491 }
492 unlock_page(page);
493 page_cache_release(page);
494
Nick Piggin54566b22009-01-04 12:00:53 -0800495 return write_begin_slow(mapping, pos, len, pagep, flags);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300496 }
497
498 /*
Artem Bityutskiy873a64c2009-09-01 17:06:43 +0300499 * Whee, we acquired budgeting quickly - without involving
500 * garbage-collection, committing or forcing write-back. We return
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300501 * with @ui->ui_mutex locked if we are appending pages, and unlocked
502 * otherwise. This is an optimization (slightly hacky though).
503 */
504 *pagep = page;
505 return 0;
506
507}
508
509/**
510 * cancel_budget - cancel budget.
511 * @c: UBIFS file-system description object
512 * @page: page to cancel budget for
513 * @ui: UBIFS inode object the page belongs to
514 * @appending: non-zero if the page is appended
515 *
516 * This is a helper function for a page write operation. It unlocks the
517 * @ui->ui_mutex in case of appending.
518 */
519static void cancel_budget(struct ubifs_info *c, struct page *page,
520 struct ubifs_inode *ui, int appending)
521{
522 if (appending) {
523 if (!ui->dirty)
524 ubifs_release_dirty_inode_budget(c, ui);
525 mutex_unlock(&ui->ui_mutex);
526 }
527 if (!PagePrivate(page)) {
528 if (PageChecked(page))
529 release_new_page_budget(c);
530 else
531 release_existing_page_budget(c);
532 }
533}
534
535static int ubifs_write_end(struct file *file, struct address_space *mapping,
536 loff_t pos, unsigned len, unsigned copied,
537 struct page *page, void *fsdata)
538{
539 struct inode *inode = mapping->host;
540 struct ubifs_inode *ui = ubifs_inode(inode);
541 struct ubifs_info *c = inode->i_sb->s_fs_info;
542 loff_t end_pos = pos + len;
543 int appending = !!(end_pos > inode->i_size);
544
545 dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
546 inode->i_ino, pos, page->index, len, copied, inode->i_size);
547
548 if (unlikely(copied < len && len == PAGE_CACHE_SIZE)) {
549 /*
550 * VFS copied less data to the page that it intended and
551 * declared in its '->write_begin()' call via the @len
552 * argument. If the page was not up-to-date, and @len was
553 * @PAGE_CACHE_SIZE, the 'ubifs_write_begin()' function did
554 * not load it from the media (for optimization reasons). This
555 * means that part of the page contains garbage. So read the
556 * page now.
557 */
558 dbg_gen("copied %d instead of %d, read page and repeat",
559 copied, len);
560 cancel_budget(c, page, ui, appending);
561
562 /*
563 * Return 0 to force VFS to repeat the whole operation, or the
Artem Bityutskiy873a64c2009-09-01 17:06:43 +0300564 * error code if 'do_readpage()' fails.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300565 */
566 copied = do_readpage(page);
567 goto out;
568 }
569
570 if (!PagePrivate(page)) {
571 SetPagePrivate(page);
572 atomic_long_inc(&c->dirty_pg_cnt);
573 __set_page_dirty_nobuffers(page);
574 }
575
576 if (appending) {
577 i_size_write(inode, end_pos);
578 ui->ui_size = end_pos;
579 /*
580 * Note, we do not set @I_DIRTY_PAGES (which means that the
581 * inode has dirty pages), this has been done in
582 * '__set_page_dirty_nobuffers()'.
583 */
584 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
585 ubifs_assert(mutex_is_locked(&ui->ui_mutex));
586 mutex_unlock(&ui->ui_mutex);
587 }
588
589out:
590 unlock_page(page);
591 page_cache_release(page);
592 return copied;
593}
594
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300595/**
596 * populate_page - copy data nodes into a page for bulk-read.
597 * @c: UBIFS file-system description object
598 * @page: page
599 * @bu: bulk-read information
600 * @n: next zbranch slot
601 *
602 * This function returns %0 on success and a negative error code on failure.
603 */
604static int populate_page(struct ubifs_info *c, struct page *page,
605 struct bu_info *bu, int *n)
606{
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300607 int i = 0, nn = *n, offs = bu->zbranch[0].offs, hole = 0, read = 0;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300608 struct inode *inode = page->mapping->host;
609 loff_t i_size = i_size_read(inode);
610 unsigned int page_block;
611 void *addr, *zaddr;
612 pgoff_t end_index;
613
614 dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
615 inode->i_ino, page->index, i_size, page->flags);
616
617 addr = zaddr = kmap(page);
618
Adrian Huntered382d52008-09-05 16:17:42 +0300619 end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300620 if (!i_size || page->index > end_index) {
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300621 hole = 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300622 memset(addr, 0, PAGE_CACHE_SIZE);
623 goto out_hole;
624 }
625
626 page_block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
627 while (1) {
628 int err, len, out_len, dlen;
629
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300630 if (nn >= bu->cnt) {
631 hole = 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300632 memset(addr, 0, UBIFS_BLOCK_SIZE);
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300633 } else if (key_block(c, &bu->zbranch[nn].key) == page_block) {
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300634 struct ubifs_data_node *dn;
635
636 dn = bu->buf + (bu->zbranch[nn].offs - offs);
637
Harvey Harrison0ecb9522008-10-24 10:52:57 -0700638 ubifs_assert(le64_to_cpu(dn->ch.sqnum) >
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300639 ubifs_inode(inode)->creat_sqnum);
640
641 len = le32_to_cpu(dn->size);
642 if (len <= 0 || len > UBIFS_BLOCK_SIZE)
643 goto out_err;
644
645 dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
646 out_len = UBIFS_BLOCK_SIZE;
647 err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
648 le16_to_cpu(dn->compr_type));
649 if (err || len != out_len)
650 goto out_err;
651
652 if (len < UBIFS_BLOCK_SIZE)
653 memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
654
655 nn += 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300656 read = (i << UBIFS_BLOCK_SHIFT) + len;
Adrian Hunter5c0013c2008-09-12 10:34:51 +0300657 } else if (key_block(c, &bu->zbranch[nn].key) < page_block) {
658 nn += 1;
659 continue;
660 } else {
661 hole = 1;
662 memset(addr, 0, UBIFS_BLOCK_SIZE);
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300663 }
664 if (++i >= UBIFS_BLOCKS_PER_PAGE)
665 break;
666 addr += UBIFS_BLOCK_SIZE;
667 page_block += 1;
668 }
669
670 if (end_index == page->index) {
671 int len = i_size & (PAGE_CACHE_SIZE - 1);
672
Adrian Huntered382d52008-09-05 16:17:42 +0300673 if (len && len < read)
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300674 memset(zaddr + len, 0, read - len);
675 }
676
677out_hole:
678 if (hole) {
679 SetPageChecked(page);
680 dbg_gen("hole");
681 }
682
683 SetPageUptodate(page);
684 ClearPageError(page);
685 flush_dcache_page(page);
686 kunmap(page);
687 *n = nn;
688 return 0;
689
690out_err:
691 ClearPageUptodate(page);
692 SetPageError(page);
693 flush_dcache_page(page);
694 kunmap(page);
695 ubifs_err("bad data node (block %u, inode %lu)",
696 page_block, inode->i_ino);
697 return -EINVAL;
698}
699
700/**
701 * ubifs_do_bulk_read - do bulk-read.
702 * @c: UBIFS file-system description object
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200703 * @bu: bulk-read information
704 * @page1: first page to read
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300705 *
706 * This function returns %1 if the bulk-read is done, otherwise %0 is returned.
707 */
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200708static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
709 struct page *page1)
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300710{
711 pgoff_t offset = page1->index, end_index;
712 struct address_space *mapping = page1->mapping;
713 struct inode *inode = mapping->host;
714 struct ubifs_inode *ui = ubifs_inode(inode);
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300715 int err, page_idx, page_cnt, ret = 0, n = 0;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200716 int allocate = bu->buf ? 0 : 1;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300717 loff_t isize;
718
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300719 err = ubifs_tnc_get_bu_keys(c, bu);
720 if (err)
721 goto out_warn;
722
723 if (bu->eof) {
724 /* Turn off bulk-read at the end of the file */
725 ui->read_in_a_row = 1;
726 ui->bulk_read = 0;
727 }
728
729 page_cnt = bu->blk_cnt >> UBIFS_BLOCKS_PER_PAGE_SHIFT;
730 if (!page_cnt) {
731 /*
732 * This happens when there are multiple blocks per page and the
733 * blocks for the first page we are looking for, are not
734 * together. If all the pages were like this, bulk-read would
735 * reduce performance, so we turn it off for a while.
736 */
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200737 goto out_bu_off;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300738 }
739
740 if (bu->cnt) {
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200741 if (allocate) {
742 /*
743 * Allocate bulk-read buffer depending on how many data
744 * nodes we are going to read.
745 */
746 bu->buf_len = bu->zbranch[bu->cnt - 1].offs +
747 bu->zbranch[bu->cnt - 1].len -
748 bu->zbranch[0].offs;
749 ubifs_assert(bu->buf_len > 0);
750 ubifs_assert(bu->buf_len <= c->leb_size);
751 bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN);
752 if (!bu->buf)
753 goto out_bu_off;
754 }
755
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300756 err = ubifs_tnc_bulk_read(c, bu);
757 if (err)
758 goto out_warn;
759 }
760
761 err = populate_page(c, page1, bu, &n);
762 if (err)
763 goto out_warn;
764
765 unlock_page(page1);
766 ret = 1;
767
768 isize = i_size_read(inode);
769 if (isize == 0)
770 goto out_free;
771 end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
772
773 for (page_idx = 1; page_idx < page_cnt; page_idx++) {
774 pgoff_t page_offset = offset + page_idx;
775 struct page *page;
776
777 if (page_offset > end_index)
778 break;
779 page = find_or_create_page(mapping, page_offset,
780 GFP_NOFS | __GFP_COLD);
781 if (!page)
782 break;
783 if (!PageUptodate(page))
784 err = populate_page(c, page, bu, &n);
785 unlock_page(page);
786 page_cache_release(page);
787 if (err)
788 break;
789 }
790
791 ui->last_page_read = offset + page_idx - 1;
792
793out_free:
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200794 if (allocate)
795 kfree(bu->buf);
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300796 return ret;
797
798out_warn:
799 ubifs_warn("ignoring error %d and skipping bulk-read", err);
800 goto out_free;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200801
802out_bu_off:
803 ui->read_in_a_row = ui->bulk_read = 0;
804 goto out_free;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300805}
806
807/**
808 * ubifs_bulk_read - determine whether to bulk-read and, if so, do it.
809 * @page: page from which to start bulk-read.
810 *
811 * Some flash media are capable of reading sequentially at faster rates. UBIFS
812 * bulk-read facility is designed to take advantage of that, by reading in one
813 * go consecutive data nodes that are also located consecutively in the same
814 * LEB. This function returns %1 if a bulk-read is done and %0 otherwise.
815 */
816static int ubifs_bulk_read(struct page *page)
817{
818 struct inode *inode = page->mapping->host;
819 struct ubifs_info *c = inode->i_sb->s_fs_info;
820 struct ubifs_inode *ui = ubifs_inode(inode);
821 pgoff_t index = page->index, last_page_read = ui->last_page_read;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200822 struct bu_info *bu;
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200823 int err = 0, allocated = 0;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300824
825 ui->last_page_read = index;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300826 if (!c->bulk_read)
827 return 0;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200828
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300829 /*
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200830 * Bulk-read is protected by @ui->ui_mutex, but it is an optimization,
831 * so don't bother if we cannot lock the mutex.
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300832 */
833 if (!mutex_trylock(&ui->ui_mutex))
834 return 0;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200835
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300836 if (index != last_page_read + 1) {
837 /* Turn off bulk-read if we stop reading sequentially */
838 ui->read_in_a_row = 1;
839 if (ui->bulk_read)
840 ui->bulk_read = 0;
841 goto out_unlock;
842 }
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200843
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300844 if (!ui->bulk_read) {
845 ui->read_in_a_row += 1;
846 if (ui->read_in_a_row < 3)
847 goto out_unlock;
848 /* Three reads in a row, so switch on bulk-read */
849 ui->bulk_read = 1;
850 }
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200851
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200852 /*
853 * If possible, try to use pre-allocated bulk-read information, which
854 * is protected by @c->bu_mutex.
855 */
856 if (mutex_trylock(&c->bu_mutex))
857 bu = &c->bu;
858 else {
859 bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN);
860 if (!bu)
861 goto out_unlock;
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200862
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200863 bu->buf = NULL;
864 allocated = 1;
865 }
866
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200867 bu->buf_len = c->max_bu_buf_len;
868 data_key_init(c, &bu->key, inode->i_ino,
869 page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT);
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200870 err = ubifs_do_bulk_read(c, bu, page);
Artem Bityutskiy3477d202008-11-19 11:53:15 +0200871
872 if (!allocated)
873 mutex_unlock(&c->bu_mutex);
874 else
875 kfree(bu);
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200876
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300877out_unlock:
878 mutex_unlock(&ui->ui_mutex);
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +0200879 return err;
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300880}
881
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300882static int ubifs_readpage(struct file *file, struct page *page)
883{
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300884 if (ubifs_bulk_read(page))
885 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300886 do_readpage(page);
887 unlock_page(page);
888 return 0;
889}
890
891static int do_writepage(struct page *page, int len)
892{
893 int err = 0, i, blen;
894 unsigned int block;
895 void *addr;
896 union ubifs_key key;
897 struct inode *inode = page->mapping->host;
898 struct ubifs_info *c = inode->i_sb->s_fs_info;
899
900#ifdef UBIFS_DEBUG
901 spin_lock(&ui->ui_lock);
902 ubifs_assert(page->index <= ui->synced_i_size << PAGE_CACHE_SIZE);
903 spin_unlock(&ui->ui_lock);
904#endif
905
906 /* Update radix tree tags */
907 set_page_writeback(page);
908
909 addr = kmap(page);
910 block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
911 i = 0;
912 while (len) {
913 blen = min_t(int, len, UBIFS_BLOCK_SIZE);
914 data_key_init(c, &key, inode->i_ino, block);
915 err = ubifs_jnl_write_data(c, inode, &key, addr, blen);
916 if (err)
917 break;
918 if (++i >= UBIFS_BLOCKS_PER_PAGE)
919 break;
920 block += 1;
921 addr += blen;
922 len -= blen;
923 }
924 if (err) {
925 SetPageError(page);
926 ubifs_err("cannot write page %lu of inode %lu, error %d",
927 page->index, inode->i_ino, err);
928 ubifs_ro_mode(c, err);
929 }
930
931 ubifs_assert(PagePrivate(page));
932 if (PageChecked(page))
933 release_new_page_budget(c);
934 else
935 release_existing_page_budget(c);
936
937 atomic_long_dec(&c->dirty_pg_cnt);
938 ClearPagePrivate(page);
939 ClearPageChecked(page);
940
941 kunmap(page);
942 unlock_page(page);
943 end_page_writeback(page);
944 return err;
945}
946
947/*
948 * When writing-back dirty inodes, VFS first writes-back pages belonging to the
949 * inode, then the inode itself. For UBIFS this may cause a problem. Consider a
950 * situation when a we have an inode with size 0, then a megabyte of data is
951 * appended to the inode, then write-back starts and flushes some amount of the
952 * dirty pages, the journal becomes full, commit happens and finishes, and then
953 * an unclean reboot happens. When the file system is mounted next time, the
954 * inode size would still be 0, but there would be many pages which are beyond
955 * the inode size, they would be indexed and consume flash space. Because the
956 * journal has been committed, the replay would not be able to detect this
957 * situation and correct the inode size. This means UBIFS would have to scan
958 * whole index and correct all inode sizes, which is long an unacceptable.
959 *
960 * To prevent situations like this, UBIFS writes pages back only if they are
Artem Bityutskiy7d4e9cc2009-03-20 19:11:12 +0200961 * within the last synchronized inode size, i.e. the size which has been
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300962 * written to the flash media last time. Otherwise, UBIFS forces inode
963 * write-back, thus making sure the on-flash inode contains current inode size,
964 * and then keeps writing pages back.
965 *
966 * Some locking issues explanation. 'ubifs_writepage()' first is called with
967 * the page locked, and it locks @ui_mutex. However, write-back does take inode
968 * @i_mutex, which means other VFS operations may be run on this inode at the
969 * same time. And the problematic one is truncation to smaller size, from where
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200970 * we have to call 'truncate_setsize()', which first changes @inode->i_size, then
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300971 * drops the truncated pages. And while dropping the pages, it takes the page
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200972 * lock. This means that 'do_truncation()' cannot call 'truncate_setsize()' with
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300973 * @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. This
974 * means that @inode->i_size is changed while @ui_mutex is unlocked.
975 *
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200976 * XXX(truncate): with the new truncate sequence this is not true anymore,
977 * and the calls to truncate_setsize can be move around freely. They should
978 * be moved to the very end of the truncate sequence.
npiggin@suse.de15c6fd92010-05-27 01:05:34 +1000979 *
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300980 * But in 'ubifs_writepage()' we have to guarantee that we do not write beyond
981 * inode size. How do we do this if @inode->i_size may became smaller while we
982 * are in the middle of 'ubifs_writepage()'? The UBIFS solution is the
983 * @ui->ui_isize "shadow" field which UBIFS uses instead of @inode->i_size
984 * internally and updates it under @ui_mutex.
985 *
986 * Q: why we do not worry that if we race with truncation, we may end up with a
987 * situation when the inode is truncated while we are in the middle of
988 * 'do_writepage()', so we do write beyond inode size?
989 * A: If we are in the middle of 'do_writepage()', truncation would be locked
990 * on the page lock and it would not write the truncated inode node to the
991 * journal before we have finished.
992 */
993static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
994{
995 struct inode *inode = page->mapping->host;
996 struct ubifs_inode *ui = ubifs_inode(inode);
997 loff_t i_size = i_size_read(inode), synced_i_size;
998 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
999 int err, len = i_size & (PAGE_CACHE_SIZE - 1);
1000 void *kaddr;
1001
1002 dbg_gen("ino %lu, pg %lu, pg flags %#lx",
1003 inode->i_ino, page->index, page->flags);
1004 ubifs_assert(PagePrivate(page));
1005
1006 /* Is the page fully outside @i_size? (truncate in progress) */
1007 if (page->index > end_index || (page->index == end_index && !len)) {
1008 err = 0;
1009 goto out_unlock;
1010 }
1011
1012 spin_lock(&ui->ui_lock);
1013 synced_i_size = ui->synced_i_size;
1014 spin_unlock(&ui->ui_lock);
1015
1016 /* Is the page fully inside @i_size? */
1017 if (page->index < end_index) {
1018 if (page->index >= synced_i_size >> PAGE_CACHE_SHIFT) {
Christoph Hellwiga9185b42010-03-05 09:21:37 +01001019 err = inode->i_sb->s_op->write_inode(inode, NULL);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001020 if (err)
1021 goto out_unlock;
1022 /*
1023 * The inode has been written, but the write-buffer has
1024 * not been synchronized, so in case of an unclean
1025 * reboot we may end up with some pages beyond inode
1026 * size, but they would be in the journal (because
1027 * commit flushes write buffers) and recovery would deal
1028 * with this.
1029 */
1030 }
1031 return do_writepage(page, PAGE_CACHE_SIZE);
1032 }
1033
1034 /*
1035 * The page straddles @i_size. It must be zeroed out on each and every
1036 * writepage invocation because it may be mmapped. "A file is mapped
1037 * in multiples of the page size. For a file that is not a multiple of
1038 * the page size, the remaining memory is zeroed when mapped, and
1039 * writes to that region are not written out to the file."
1040 */
1041 kaddr = kmap_atomic(page, KM_USER0);
1042 memset(kaddr + len, 0, PAGE_CACHE_SIZE - len);
1043 flush_dcache_page(page);
1044 kunmap_atomic(kaddr, KM_USER0);
1045
1046 if (i_size > synced_i_size) {
Christoph Hellwiga9185b42010-03-05 09:21:37 +01001047 err = inode->i_sb->s_op->write_inode(inode, NULL);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001048 if (err)
1049 goto out_unlock;
1050 }
1051
1052 return do_writepage(page, len);
1053
1054out_unlock:
1055 unlock_page(page);
1056 return err;
1057}
1058
1059/**
1060 * do_attr_changes - change inode attributes.
1061 * @inode: inode to change attributes for
1062 * @attr: describes attributes to change
1063 */
1064static void do_attr_changes(struct inode *inode, const struct iattr *attr)
1065{
1066 if (attr->ia_valid & ATTR_UID)
1067 inode->i_uid = attr->ia_uid;
1068 if (attr->ia_valid & ATTR_GID)
1069 inode->i_gid = attr->ia_gid;
1070 if (attr->ia_valid & ATTR_ATIME)
1071 inode->i_atime = timespec_trunc(attr->ia_atime,
1072 inode->i_sb->s_time_gran);
1073 if (attr->ia_valid & ATTR_MTIME)
1074 inode->i_mtime = timespec_trunc(attr->ia_mtime,
1075 inode->i_sb->s_time_gran);
1076 if (attr->ia_valid & ATTR_CTIME)
1077 inode->i_ctime = timespec_trunc(attr->ia_ctime,
1078 inode->i_sb->s_time_gran);
1079 if (attr->ia_valid & ATTR_MODE) {
1080 umode_t mode = attr->ia_mode;
1081
1082 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
1083 mode &= ~S_ISGID;
1084 inode->i_mode = mode;
1085 }
1086}
1087
1088/**
1089 * do_truncation - truncate an inode.
1090 * @c: UBIFS file-system description object
1091 * @inode: inode to truncate
1092 * @attr: inode attribute changes description
1093 *
1094 * This function implements VFS '->setattr()' call when the inode is truncated
1095 * to a smaller size. Returns zero in case of success and a negative error code
1096 * in case of failure.
1097 */
1098static int do_truncation(struct ubifs_info *c, struct inode *inode,
1099 const struct iattr *attr)
1100{
1101 int err;
1102 struct ubifs_budget_req req;
1103 loff_t old_size = inode->i_size, new_size = attr->ia_size;
Artem Bityutskiy04da11b2008-08-20 17:16:34 +03001104 int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001105 struct ubifs_inode *ui = ubifs_inode(inode);
1106
1107 dbg_gen("ino %lu, size %lld -> %lld", inode->i_ino, old_size, new_size);
1108 memset(&req, 0, sizeof(struct ubifs_budget_req));
1109
1110 /*
1111 * If this is truncation to a smaller size, and we do not truncate on a
1112 * block boundary, budget for changing one data block, because the last
1113 * block will be re-written.
1114 */
1115 if (new_size & (UBIFS_BLOCK_SIZE - 1))
1116 req.dirtied_page = 1;
1117
1118 req.dirtied_ino = 1;
1119 /* A funny way to budget for truncation node */
1120 req.dirtied_ino_d = UBIFS_TRUN_NODE_SZ;
1121 err = ubifs_budget_space(c, &req);
Artem Bityutskiy04da11b2008-08-20 17:16:34 +03001122 if (err) {
1123 /*
1124 * Treat truncations to zero as deletion and always allow them,
1125 * just like we do for '->unlink()'.
1126 */
1127 if (new_size || err != -ENOSPC)
1128 return err;
1129 budgeted = 0;
1130 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001131
Christoph Hellwig2c27c652010-06-04 11:30:04 +02001132 truncate_setsize(inode, new_size);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001133
1134 if (offset) {
1135 pgoff_t index = new_size >> PAGE_CACHE_SHIFT;
1136 struct page *page;
1137
1138 page = find_lock_page(inode->i_mapping, index);
1139 if (page) {
1140 if (PageDirty(page)) {
1141 /*
1142 * 'ubifs_jnl_truncate()' will try to truncate
1143 * the last data node, but it contains
1144 * out-of-date data because the page is dirty.
1145 * Write the page now, so that
1146 * 'ubifs_jnl_truncate()' will see an already
1147 * truncated (and up to date) data node.
1148 */
1149 ubifs_assert(PagePrivate(page));
1150
1151 clear_page_dirty_for_io(page);
1152 if (UBIFS_BLOCKS_PER_PAGE_SHIFT)
1153 offset = new_size &
1154 (PAGE_CACHE_SIZE - 1);
1155 err = do_writepage(page, offset);
1156 page_cache_release(page);
1157 if (err)
1158 goto out_budg;
1159 /*
1160 * We could now tell 'ubifs_jnl_truncate()' not
1161 * to read the last block.
1162 */
1163 } else {
1164 /*
1165 * We could 'kmap()' the page and pass the data
1166 * to 'ubifs_jnl_truncate()' to save it from
1167 * having to read it.
1168 */
1169 unlock_page(page);
1170 page_cache_release(page);
1171 }
1172 }
1173 }
1174
1175 mutex_lock(&ui->ui_mutex);
1176 ui->ui_size = inode->i_size;
1177 /* Truncation changes inode [mc]time */
1178 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
Artem Bityutskiy873a64c2009-09-01 17:06:43 +03001179 /* Other attributes may be changed at the same time as well */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001180 do_attr_changes(inode, attr);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001181 err = ubifs_jnl_truncate(c, inode, old_size, new_size);
1182 mutex_unlock(&ui->ui_mutex);
Artem Bityutskiy873a64c2009-09-01 17:06:43 +03001183
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001184out_budg:
Artem Bityutskiy04da11b2008-08-20 17:16:34 +03001185 if (budgeted)
1186 ubifs_release_budget(c, &req);
1187 else {
1188 c->nospace = c->nospace_rp = 0;
1189 smp_wmb();
1190 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001191 return err;
1192}
1193
1194/**
1195 * do_setattr - change inode attributes.
1196 * @c: UBIFS file-system description object
1197 * @inode: inode to change attributes for
1198 * @attr: inode attribute changes description
1199 *
1200 * This function implements VFS '->setattr()' call for all cases except
1201 * truncations to smaller size. Returns zero in case of success and a negative
1202 * error code in case of failure.
1203 */
1204static int do_setattr(struct ubifs_info *c, struct inode *inode,
1205 const struct iattr *attr)
1206{
1207 int err, release;
1208 loff_t new_size = attr->ia_size;
1209 struct ubifs_inode *ui = ubifs_inode(inode);
1210 struct ubifs_budget_req req = { .dirtied_ino = 1,
Artem Bityutskiydab4b4d2008-07-24 14:52:45 +03001211 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001212
1213 err = ubifs_budget_space(c, &req);
1214 if (err)
1215 return err;
1216
1217 if (attr->ia_valid & ATTR_SIZE) {
1218 dbg_gen("size %lld -> %lld", inode->i_size, new_size);
Christoph Hellwig2c27c652010-06-04 11:30:04 +02001219 truncate_setsize(inode, new_size);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001220 }
1221
1222 mutex_lock(&ui->ui_mutex);
1223 if (attr->ia_valid & ATTR_SIZE) {
1224 /* Truncation changes inode [mc]time */
1225 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
Christoph Hellwig2c27c652010-06-04 11:30:04 +02001226 /* 'truncate_setsize()' changed @i_size, update @ui_size */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001227 ui->ui_size = inode->i_size;
1228 }
1229
1230 do_attr_changes(inode, attr);
1231
1232 release = ui->dirty;
1233 if (attr->ia_valid & ATTR_SIZE)
1234 /*
1235 * Inode length changed, so we have to make sure
1236 * @I_DIRTY_DATASYNC is set.
1237 */
1238 __mark_inode_dirty(inode, I_DIRTY_SYNC | I_DIRTY_DATASYNC);
1239 else
1240 mark_inode_dirty_sync(inode);
1241 mutex_unlock(&ui->ui_mutex);
1242
1243 if (release)
1244 ubifs_release_budget(c, &req);
1245 if (IS_SYNC(inode))
Christoph Hellwiga9185b42010-03-05 09:21:37 +01001246 err = inode->i_sb->s_op->write_inode(inode, NULL);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001247 return err;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001248}
1249
1250int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
1251{
1252 int err;
1253 struct inode *inode = dentry->d_inode;
1254 struct ubifs_info *c = inode->i_sb->s_fs_info;
1255
Artem Bityutskiy7d32c2b2008-07-18 18:54:29 +03001256 dbg_gen("ino %lu, mode %#x, ia_valid %#x",
1257 inode->i_ino, inode->i_mode, attr->ia_valid);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001258 err = inode_change_ok(inode, attr);
1259 if (err)
1260 return err;
1261
1262 err = dbg_check_synced_i_size(inode);
1263 if (err)
1264 return err;
1265
1266 if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size < inode->i_size)
1267 /* Truncation to a smaller size */
1268 err = do_truncation(c, inode, attr);
1269 else
1270 err = do_setattr(c, inode, attr);
1271
1272 return err;
1273}
1274
1275static void ubifs_invalidatepage(struct page *page, unsigned long offset)
1276{
1277 struct inode *inode = page->mapping->host;
1278 struct ubifs_info *c = inode->i_sb->s_fs_info;
1279
1280 ubifs_assert(PagePrivate(page));
1281 if (offset)
1282 /* Partial page remains dirty */
1283 return;
1284
1285 if (PageChecked(page))
1286 release_new_page_budget(c);
1287 else
1288 release_existing_page_budget(c);
1289
1290 atomic_long_dec(&c->dirty_pg_cnt);
1291 ClearPagePrivate(page);
1292 ClearPageChecked(page);
1293}
1294
1295static void *ubifs_follow_link(struct dentry *dentry, struct nameidata *nd)
1296{
1297 struct ubifs_inode *ui = ubifs_inode(dentry->d_inode);
1298
1299 nd_set_link(nd, ui->data);
1300 return NULL;
1301}
1302
Christoph Hellwig7ea80852010-05-26 17:53:25 +02001303int ubifs_fsync(struct file *file, int datasync)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001304{
Christoph Hellwig7ea80852010-05-26 17:53:25 +02001305 struct inode *inode = file->f_mapping->host;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001306 struct ubifs_info *c = inode->i_sb->s_fs_info;
1307 int err;
1308
1309 dbg_gen("syncing inode %lu", inode->i_ino);
1310
1311 /*
1312 * VFS has already synchronized dirty pages for this inode. Synchronize
1313 * the inode unless this is a 'datasync()' call.
1314 */
1315 if (!datasync || (inode->i_state & I_DIRTY_DATASYNC)) {
Christoph Hellwiga9185b42010-03-05 09:21:37 +01001316 err = inode->i_sb->s_op->write_inode(inode, NULL);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001317 if (err)
1318 return err;
1319 }
1320
1321 /*
1322 * Nodes related to this inode may still sit in a write-buffer. Flush
1323 * them.
1324 */
1325 err = ubifs_sync_wbufs_by_inode(c, inode);
1326 if (err)
1327 return err;
1328
1329 return 0;
1330}
1331
1332/**
1333 * mctime_update_needed - check if mtime or ctime update is needed.
1334 * @inode: the inode to do the check for
1335 * @now: current time
1336 *
1337 * This helper function checks if the inode mtime/ctime should be updated or
1338 * not. If current values of the time-stamps are within the UBIFS inode time
1339 * granularity, they are not updated. This is an optimization.
1340 */
1341static inline int mctime_update_needed(const struct inode *inode,
1342 const struct timespec *now)
1343{
1344 if (!timespec_equal(&inode->i_mtime, now) ||
1345 !timespec_equal(&inode->i_ctime, now))
1346 return 1;
1347 return 0;
1348}
1349
1350/**
1351 * update_ctime - update mtime and ctime of an inode.
1352 * @c: UBIFS file-system description object
1353 * @inode: inode to update
1354 *
1355 * This function updates mtime and ctime of the inode if it is not equivalent to
1356 * current time. Returns zero in case of success and a negative error code in
1357 * case of failure.
1358 */
1359static int update_mctime(struct ubifs_info *c, struct inode *inode)
1360{
1361 struct timespec now = ubifs_current_time(inode);
1362 struct ubifs_inode *ui = ubifs_inode(inode);
1363
1364 if (mctime_update_needed(inode, &now)) {
1365 int err, release;
1366 struct ubifs_budget_req req = { .dirtied_ino = 1,
Artem Bityutskiydab4b4d2008-07-24 14:52:45 +03001367 .dirtied_ino_d = ALIGN(ui->data_len, 8) };
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001368
1369 err = ubifs_budget_space(c, &req);
1370 if (err)
1371 return err;
1372
1373 mutex_lock(&ui->ui_mutex);
1374 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1375 release = ui->dirty;
1376 mark_inode_dirty_sync(inode);
1377 mutex_unlock(&ui->ui_mutex);
1378 if (release)
1379 ubifs_release_budget(c, &req);
1380 }
1381
1382 return 0;
1383}
1384
1385static ssize_t ubifs_aio_write(struct kiocb *iocb, const struct iovec *iov,
1386 unsigned long nr_segs, loff_t pos)
1387{
1388 int err;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001389 struct inode *inode = iocb->ki_filp->f_mapping->host;
1390 struct ubifs_info *c = inode->i_sb->s_fs_info;
1391
1392 err = update_mctime(c, inode);
1393 if (err)
1394 return err;
1395
Christoph Hellwig774888b2009-09-30 22:17:16 +02001396 return generic_file_aio_write(iocb, iov, nr_segs, pos);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001397}
1398
1399static int ubifs_set_page_dirty(struct page *page)
1400{
1401 int ret;
1402
1403 ret = __set_page_dirty_nobuffers(page);
1404 /*
1405 * An attempt to dirty a page without budgeting for it - should not
1406 * happen.
1407 */
1408 ubifs_assert(ret == 0);
1409 return ret;
1410}
1411
1412static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
1413{
1414 /*
1415 * An attempt to release a dirty page without budgeting for it - should
1416 * not happen.
1417 */
1418 if (PageWriteback(page))
1419 return 0;
1420 ubifs_assert(PagePrivate(page));
1421 ubifs_assert(0);
1422 ClearPagePrivate(page);
1423 ClearPageChecked(page);
1424 return 1;
1425}
1426
1427/*
1428 * mmap()d file has taken write protection fault and is being made
1429 * writable. UBIFS must ensure page is budgeted for.
1430 */
Nick Pigginc2ec1752009-03-31 15:23:21 -07001431static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001432{
Nick Pigginc2ec1752009-03-31 15:23:21 -07001433 struct page *page = vmf->page;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001434 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
1435 struct ubifs_info *c = inode->i_sb->s_fs_info;
1436 struct timespec now = ubifs_current_time(inode);
1437 struct ubifs_budget_req req = { .new_page = 1 };
1438 int err, update_time;
1439
1440 dbg_gen("ino %lu, pg %lu, i_size %lld", inode->i_ino, page->index,
1441 i_size_read(inode));
1442 ubifs_assert(!(inode->i_sb->s_flags & MS_RDONLY));
1443
1444 if (unlikely(c->ro_media))
Nick Pigginc2ec1752009-03-31 15:23:21 -07001445 return VM_FAULT_SIGBUS; /* -EROFS */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001446
1447 /*
1448 * We have not locked @page so far so we may budget for changing the
1449 * page. Note, we cannot do this after we locked the page, because
1450 * budgeting may cause write-back which would cause deadlock.
1451 *
1452 * At the moment we do not know whether the page is dirty or not, so we
1453 * assume that it is not and budget for a new page. We could look at
1454 * the @PG_private flag and figure this out, but we may race with write
1455 * back and the page state may change by the time we lock it, so this
1456 * would need additional care. We do not bother with this at the
1457 * moment, although it might be good idea to do. Instead, we allocate
1458 * budget for a new page and amend it later on if the page was in fact
1459 * dirty.
1460 *
1461 * The budgeting-related logic of this function is similar to what we
1462 * do in 'ubifs_write_begin()' and 'ubifs_write_end()'. Glance there
1463 * for more comments.
1464 */
1465 update_time = mctime_update_needed(inode, &now);
1466 if (update_time)
1467 /*
1468 * We have to change inode time stamp which requires extra
1469 * budgeting.
1470 */
1471 req.dirtied_ino = 1;
1472
1473 err = ubifs_budget_space(c, &req);
1474 if (unlikely(err)) {
1475 if (err == -ENOSPC)
1476 ubifs_warn("out of space for mmapped file "
1477 "(inode number %lu)", inode->i_ino);
Nick Pigginc2ec1752009-03-31 15:23:21 -07001478 return VM_FAULT_SIGBUS;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001479 }
1480
1481 lock_page(page);
1482 if (unlikely(page->mapping != inode->i_mapping ||
1483 page_offset(page) > i_size_read(inode))) {
1484 /* Page got truncated out from underneath us */
1485 err = -EINVAL;
1486 goto out_unlock;
1487 }
1488
1489 if (PagePrivate(page))
1490 release_new_page_budget(c);
1491 else {
1492 if (!PageChecked(page))
1493 ubifs_convert_page_budget(c);
1494 SetPagePrivate(page);
1495 atomic_long_inc(&c->dirty_pg_cnt);
1496 __set_page_dirty_nobuffers(page);
1497 }
1498
1499 if (update_time) {
1500 int release;
1501 struct ubifs_inode *ui = ubifs_inode(inode);
1502
1503 mutex_lock(&ui->ui_mutex);
1504 inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
1505 release = ui->dirty;
1506 mark_inode_dirty_sync(inode);
1507 mutex_unlock(&ui->ui_mutex);
1508 if (release)
1509 ubifs_release_dirty_inode_budget(c, ui);
1510 }
1511
1512 unlock_page(page);
1513 return 0;
1514
1515out_unlock:
1516 unlock_page(page);
1517 ubifs_release_budget(c, &req);
Nick Pigginc2ec1752009-03-31 15:23:21 -07001518 if (err)
1519 err = VM_FAULT_SIGBUS;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001520 return err;
1521}
1522
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +04001523static const struct vm_operations_struct ubifs_file_vm_ops = {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001524 .fault = filemap_fault,
1525 .page_mkwrite = ubifs_vm_page_mkwrite,
1526};
1527
1528static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
1529{
1530 int err;
1531
1532 /* 'generic_file_mmap()' takes care of NOMMU case */
1533 err = generic_file_mmap(file, vma);
1534 if (err)
1535 return err;
1536 vma->vm_ops = &ubifs_file_vm_ops;
1537 return 0;
1538}
1539
Artem Bityutskiye8b81562009-01-15 17:43:23 +02001540const struct address_space_operations ubifs_file_address_operations = {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001541 .readpage = ubifs_readpage,
1542 .writepage = ubifs_writepage,
1543 .write_begin = ubifs_write_begin,
1544 .write_end = ubifs_write_end,
1545 .invalidatepage = ubifs_invalidatepage,
1546 .set_page_dirty = ubifs_set_page_dirty,
1547 .releasepage = ubifs_releasepage,
1548};
1549
Artem Bityutskiye8b81562009-01-15 17:43:23 +02001550const struct inode_operations ubifs_file_inode_operations = {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001551 .setattr = ubifs_setattr,
1552 .getattr = ubifs_getattr,
1553#ifdef CONFIG_UBIFS_FS_XATTR
1554 .setxattr = ubifs_setxattr,
1555 .getxattr = ubifs_getxattr,
1556 .listxattr = ubifs_listxattr,
1557 .removexattr = ubifs_removexattr,
1558#endif
1559};
1560
Artem Bityutskiye8b81562009-01-15 17:43:23 +02001561const struct inode_operations ubifs_symlink_inode_operations = {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001562 .readlink = generic_readlink,
1563 .follow_link = ubifs_follow_link,
1564 .setattr = ubifs_setattr,
1565 .getattr = ubifs_getattr,
1566};
1567
Artem Bityutskiye8b81562009-01-15 17:43:23 +02001568const struct file_operations ubifs_file_operations = {
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001569 .llseek = generic_file_llseek,
1570 .read = do_sync_read,
1571 .write = do_sync_write,
1572 .aio_read = generic_file_aio_read,
1573 .aio_write = ubifs_aio_write,
1574 .mmap = ubifs_file_mmap,
1575 .fsync = ubifs_fsync,
1576 .unlocked_ioctl = ubifs_ioctl,
1577 .splice_read = generic_file_splice_read,
Zoltan Sogor22bc7fa2008-07-28 16:28:49 +02001578 .splice_write = generic_file_splice_write,
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001579#ifdef CONFIG_COMPAT
1580 .compat_ioctl = ubifs_compat_ioctl,
1581#endif
1582};