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1/*
2 * linux/fs/ext4/inode.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * 64-bit file support on 64-bit platforms by Jakub Jelinek
16 * (jj@sunsite.ms.mff.cuni.cz)
17 *
18 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
19 */
20
21#include <linux/module.h>
22#include <linux/fs.h>
23#include <linux/time.h>
24#include <linux/jbd2.h>
25#include <linux/highuid.h>
26#include <linux/pagemap.h>
27#include <linux/quotaops.h>
28#include <linux/string.h>
29#include <linux/buffer_head.h>
30#include <linux/writeback.h>
31#include <linux/pagevec.h>
32#include <linux/mpage.h>
33#include <linux/namei.h>
34#include <linux/uio.h>
35#include <linux/bio.h>
36#include <linux/workqueue.h>
37#include <linux/kernel.h>
38#include <linux/printk.h>
39#include <linux/slab.h>
40#include <linux/ratelimit.h>
41
42#include "ext4_jbd2.h"
43#include "xattr.h"
44#include "acl.h"
45#include "ext4_extents.h"
46#include "truncate.h"
47
48#include <trace/events/ext4.h>
49
50#define MPAGE_DA_EXTENT_TAIL 0x01
51
52static inline int ext4_begin_ordered_truncate(struct inode *inode,
53 loff_t new_size)
54{
55 trace_ext4_begin_ordered_truncate(inode, new_size);
56 /*
57 * If jinode is zero, then we never opened the file for
58 * writing, so there's no need to call
59 * jbd2_journal_begin_ordered_truncate() since there's no
60 * outstanding writes we need to flush.
61 */
62 if (!EXT4_I(inode)->jinode)
63 return 0;
64 return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
65 EXT4_I(inode)->jinode,
66 new_size);
67}
68
69static void ext4_invalidatepage(struct page *page, unsigned long offset);
70static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
71 struct buffer_head *bh_result, int create);
72static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
73static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
74static int __ext4_journalled_writepage(struct page *page, unsigned int len);
75static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
76
77/*
78 * Test whether an inode is a fast symlink.
79 */
80static int ext4_inode_is_fast_symlink(struct inode *inode)
81{
82 int ea_blocks = EXT4_I(inode)->i_file_acl ?
83 (inode->i_sb->s_blocksize >> 9) : 0;
84
85 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
86}
87
88/*
89 * Restart the transaction associated with *handle. This does a commit,
90 * so before we call here everything must be consistently dirtied against
91 * this transaction.
92 */
93int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
94 int nblocks)
95{
96 int ret;
97
98 /*
99 * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
100 * moment, get_block can be called only for blocks inside i_size since
101 * page cache has been already dropped and writes are blocked by
102 * i_mutex. So we can safely drop the i_data_sem here.
103 */
104 BUG_ON(EXT4_JOURNAL(inode) == NULL);
105 jbd_debug(2, "restarting handle %p\n", handle);
106 up_write(&EXT4_I(inode)->i_data_sem);
107 ret = ext4_journal_restart(handle, nblocks);
108 down_write(&EXT4_I(inode)->i_data_sem);
109 ext4_discard_preallocations(inode);
110
111 return ret;
112}
113
114/*
115 * Called at the last iput() if i_nlink is zero.
116 */
117void ext4_evict_inode(struct inode *inode)
118{
119 handle_t *handle;
120 int err;
121
122 trace_ext4_evict_inode(inode);
123
124 ext4_ioend_wait(inode);
125
126 if (inode->i_nlink) {
127 /*
128 * When journalling data dirty buffers are tracked only in the
129 * journal. So although mm thinks everything is clean and
130 * ready for reaping the inode might still have some pages to
131 * write in the running transaction or waiting to be
132 * checkpointed. Thus calling jbd2_journal_invalidatepage()
133 * (via truncate_inode_pages()) to discard these buffers can
134 * cause data loss. Also even if we did not discard these
135 * buffers, we would have no way to find them after the inode
136 * is reaped and thus user could see stale data if he tries to
137 * read them before the transaction is checkpointed. So be
138 * careful and force everything to disk here... We use
139 * ei->i_datasync_tid to store the newest transaction
140 * containing inode's data.
141 *
142 * Note that directories do not have this problem because they
143 * don't use page cache.
144 */
145 if (ext4_should_journal_data(inode) &&
146 (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
147 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
148 tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
149
150 jbd2_log_start_commit(journal, commit_tid);
151 jbd2_log_wait_commit(journal, commit_tid);
152 filemap_write_and_wait(&inode->i_data);
153 }
154 truncate_inode_pages(&inode->i_data, 0);
155 goto no_delete;
156 }
157
158 if (!is_bad_inode(inode))
159 dquot_initialize(inode);
160
161 if (ext4_should_order_data(inode))
162 ext4_begin_ordered_truncate(inode, 0);
163 truncate_inode_pages(&inode->i_data, 0);
164
165 if (is_bad_inode(inode))
166 goto no_delete;
167
168 handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3);
169 if (IS_ERR(handle)) {
170 ext4_std_error(inode->i_sb, PTR_ERR(handle));
171 /*
172 * If we're going to skip the normal cleanup, we still need to
173 * make sure that the in-core orphan linked list is properly
174 * cleaned up.
175 */
176 ext4_orphan_del(NULL, inode);
177 goto no_delete;
178 }
179
180 if (IS_SYNC(inode))
181 ext4_handle_sync(handle);
182 inode->i_size = 0;
183 err = ext4_mark_inode_dirty(handle, inode);
184 if (err) {
185 ext4_warning(inode->i_sb,
186 "couldn't mark inode dirty (err %d)", err);
187 goto stop_handle;
188 }
189 if (inode->i_blocks)
190 ext4_truncate(inode);
191
192 /*
193 * ext4_ext_truncate() doesn't reserve any slop when it
194 * restarts journal transactions; therefore there may not be
195 * enough credits left in the handle to remove the inode from
196 * the orphan list and set the dtime field.
197 */
198 if (!ext4_handle_has_enough_credits(handle, 3)) {
199 err = ext4_journal_extend(handle, 3);
200 if (err > 0)
201 err = ext4_journal_restart(handle, 3);
202 if (err != 0) {
203 ext4_warning(inode->i_sb,
204 "couldn't extend journal (err %d)", err);
205 stop_handle:
206 ext4_journal_stop(handle);
207 ext4_orphan_del(NULL, inode);
208 goto no_delete;
209 }
210 }
211
212 /*
213 * Kill off the orphan record which ext4_truncate created.
214 * AKPM: I think this can be inside the above `if'.
215 * Note that ext4_orphan_del() has to be able to cope with the
216 * deletion of a non-existent orphan - this is because we don't
217 * know if ext4_truncate() actually created an orphan record.
218 * (Well, we could do this if we need to, but heck - it works)
219 */
220 ext4_orphan_del(handle, inode);
221 EXT4_I(inode)->i_dtime = get_seconds();
222
223 /*
224 * One subtle ordering requirement: if anything has gone wrong
225 * (transaction abort, IO errors, whatever), then we can still
226 * do these next steps (the fs will already have been marked as
227 * having errors), but we can't free the inode if the mark_dirty
228 * fails.
229 */
230 if (ext4_mark_inode_dirty(handle, inode))
231 /* If that failed, just do the required in-core inode clear. */
232 ext4_clear_inode(inode);
233 else
234 ext4_free_inode(handle, inode);
235 ext4_journal_stop(handle);
236 return;
237no_delete:
238 ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
239}
240
241#ifdef CONFIG_QUOTA
242qsize_t *ext4_get_reserved_space(struct inode *inode)
243{
244 return &EXT4_I(inode)->i_reserved_quota;
245}
246#endif
247
248/*
249 * Calculate the number of metadata blocks need to reserve
250 * to allocate a block located at @lblock
251 */
252static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
253{
254 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
255 return ext4_ext_calc_metadata_amount(inode, lblock);
256
257 return ext4_ind_calc_metadata_amount(inode, lblock);
258}
259
260/*
261 * Called with i_data_sem down, which is important since we can call
262 * ext4_discard_preallocations() from here.
263 */
264void ext4_da_update_reserve_space(struct inode *inode,
265 int used, int quota_claim)
266{
267 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
268 struct ext4_inode_info *ei = EXT4_I(inode);
269
270 spin_lock(&ei->i_block_reservation_lock);
271 trace_ext4_da_update_reserve_space(inode, used);
272 if (unlikely(used > ei->i_reserved_data_blocks)) {
273 ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
274 "with only %d reserved data blocks\n",
275 __func__, inode->i_ino, used,
276 ei->i_reserved_data_blocks);
277 WARN_ON(1);
278 used = ei->i_reserved_data_blocks;
279 }
280
281 /* Update per-inode reservations */
282 ei->i_reserved_data_blocks -= used;
283 ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
284 percpu_counter_sub(&sbi->s_dirtyblocks_counter,
285 used + ei->i_allocated_meta_blocks);
286 ei->i_allocated_meta_blocks = 0;
287
288 if (ei->i_reserved_data_blocks == 0) {
289 /*
290 * We can release all of the reserved metadata blocks
291 * only when we have written all of the delayed
292 * allocation blocks.
293 */
294 percpu_counter_sub(&sbi->s_dirtyblocks_counter,
295 ei->i_reserved_meta_blocks);
296 ei->i_reserved_meta_blocks = 0;
297 ei->i_da_metadata_calc_len = 0;
298 }
299 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
300
301 /* Update quota subsystem for data blocks */
302 if (quota_claim)
303 dquot_claim_block(inode, used);
304 else {
305 /*
306 * We did fallocate with an offset that is already delayed
307 * allocated. So on delayed allocated writeback we should
308 * not re-claim the quota for fallocated blocks.
309 */
310 dquot_release_reservation_block(inode, used);
311 }
312
313 /*
314 * If we have done all the pending block allocations and if
315 * there aren't any writers on the inode, we can discard the
316 * inode's preallocations.
317 */
318 if ((ei->i_reserved_data_blocks == 0) &&
319 (atomic_read(&inode->i_writecount) == 0))
320 ext4_discard_preallocations(inode);
321}
322
323static int __check_block_validity(struct inode *inode, const char *func,
324 unsigned int line,
325 struct ext4_map_blocks *map)
326{
327 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
328 map->m_len)) {
329 ext4_error_inode(inode, func, line, map->m_pblk,
330 "lblock %lu mapped to illegal pblock "
331 "(length %d)", (unsigned long) map->m_lblk,
332 map->m_len);
333 return -EIO;
334 }
335 return 0;
336}
337
338#define check_block_validity(inode, map) \
339 __check_block_validity((inode), __func__, __LINE__, (map))
340
341/*
342 * Return the number of contiguous dirty pages in a given inode
343 * starting at page frame idx.
344 */
345static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
346 unsigned int max_pages)
347{
348 struct address_space *mapping = inode->i_mapping;
349 pgoff_t index;
350 struct pagevec pvec;
351 pgoff_t num = 0;
352 int i, nr_pages, done = 0;
353
354 if (max_pages == 0)
355 return 0;
356 pagevec_init(&pvec, 0);
357 while (!done) {
358 index = idx;
359 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
360 PAGECACHE_TAG_DIRTY,
361 (pgoff_t)PAGEVEC_SIZE);
362 if (nr_pages == 0)
363 break;
364 for (i = 0; i < nr_pages; i++) {
365 struct page *page = pvec.pages[i];
366 struct buffer_head *bh, *head;
367
368 lock_page(page);
369 if (unlikely(page->mapping != mapping) ||
370 !PageDirty(page) ||
371 PageWriteback(page) ||
372 page->index != idx) {
373 done = 1;
374 unlock_page(page);
375 break;
376 }
377 if (page_has_buffers(page)) {
378 bh = head = page_buffers(page);
379 do {
380 if (!buffer_delay(bh) &&
381 !buffer_unwritten(bh))
382 done = 1;
383 bh = bh->b_this_page;
384 } while (!done && (bh != head));
385 }
386 unlock_page(page);
387 if (done)
388 break;
389 idx++;
390 num++;
391 if (num >= max_pages) {
392 done = 1;
393 break;
394 }
395 }
396 pagevec_release(&pvec);
397 }
398 return num;
399}
400
401/*
402 * The ext4_map_blocks() function tries to look up the requested blocks,
403 * and returns if the blocks are already mapped.
404 *
405 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
406 * and store the allocated blocks in the result buffer head and mark it
407 * mapped.
408 *
409 * If file type is extents based, it will call ext4_ext_map_blocks(),
410 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
411 * based files
412 *
413 * On success, it returns the number of blocks being mapped or allocate.
414 * if create==0 and the blocks are pre-allocated and uninitialized block,
415 * the result buffer head is unmapped. If the create ==1, it will make sure
416 * the buffer head is mapped.
417 *
418 * It returns 0 if plain look up failed (blocks have not been allocated), in
419 * that casem, buffer head is unmapped
420 *
421 * It returns the error in case of allocation failure.
422 */
423int ext4_map_blocks(handle_t *handle, struct inode *inode,
424 struct ext4_map_blocks *map, int flags)
425{
426 int retval;
427
428 map->m_flags = 0;
429 ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
430 "logical block %lu\n", inode->i_ino, flags, map->m_len,
431 (unsigned long) map->m_lblk);
432 /*
433 * Try to see if we can get the block without requesting a new
434 * file system block.
435 */
436 down_read((&EXT4_I(inode)->i_data_sem));
437 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
438 retval = ext4_ext_map_blocks(handle, inode, map, 0);
439 } else {
440 retval = ext4_ind_map_blocks(handle, inode, map, 0);
441 }
442 up_read((&EXT4_I(inode)->i_data_sem));
443
444 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
445 int ret = check_block_validity(inode, map);
446 if (ret != 0)
447 return ret;
448 }
449
450 /* If it is only a block(s) look up */
451 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
452 return retval;
453
454 /*
455 * Returns if the blocks have already allocated
456 *
457 * Note that if blocks have been preallocated
458 * ext4_ext_get_block() returns th create = 0
459 * with buffer head unmapped.
460 */
461 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
462 return retval;
463
464 /*
465 * When we call get_blocks without the create flag, the
466 * BH_Unwritten flag could have gotten set if the blocks
467 * requested were part of a uninitialized extent. We need to
468 * clear this flag now that we are committed to convert all or
469 * part of the uninitialized extent to be an initialized
470 * extent. This is because we need to avoid the combination
471 * of BH_Unwritten and BH_Mapped flags being simultaneously
472 * set on the buffer_head.
473 */
474 map->m_flags &= ~EXT4_MAP_UNWRITTEN;
475
476 /*
477 * New blocks allocate and/or writing to uninitialized extent
478 * will possibly result in updating i_data, so we take
479 * the write lock of i_data_sem, and call get_blocks()
480 * with create == 1 flag.
481 */
482 down_write((&EXT4_I(inode)->i_data_sem));
483
484 /*
485 * if the caller is from delayed allocation writeout path
486 * we have already reserved fs blocks for allocation
487 * let the underlying get_block() function know to
488 * avoid double accounting
489 */
490 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
491 ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
492 /*
493 * We need to check for EXT4 here because migrate
494 * could have changed the inode type in between
495 */
496 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
497 retval = ext4_ext_map_blocks(handle, inode, map, flags);
498 } else {
499 retval = ext4_ind_map_blocks(handle, inode, map, flags);
500
501 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
502 /*
503 * We allocated new blocks which will result in
504 * i_data's format changing. Force the migrate
505 * to fail by clearing migrate flags
506 */
507 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
508 }
509
510 /*
511 * Update reserved blocks/metadata blocks after successful
512 * block allocation which had been deferred till now. We don't
513 * support fallocate for non extent files. So we can update
514 * reserve space here.
515 */
516 if ((retval > 0) &&
517 (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
518 ext4_da_update_reserve_space(inode, retval, 1);
519 }
520 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
521 ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
522
523 up_write((&EXT4_I(inode)->i_data_sem));
524 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
525 int ret = check_block_validity(inode, map);
526 if (ret != 0)
527 return ret;
528 }
529 return retval;
530}
531
532/* Maximum number of blocks we map for direct IO at once. */
533#define DIO_MAX_BLOCKS 4096
534
535static int _ext4_get_block(struct inode *inode, sector_t iblock,
536 struct buffer_head *bh, int flags)
537{
538 handle_t *handle = ext4_journal_current_handle();
539 struct ext4_map_blocks map;
540 int ret = 0, started = 0;
541 int dio_credits;
542
543 map.m_lblk = iblock;
544 map.m_len = bh->b_size >> inode->i_blkbits;
545
546 if (flags && !handle) {
547 /* Direct IO write... */
548 if (map.m_len > DIO_MAX_BLOCKS)
549 map.m_len = DIO_MAX_BLOCKS;
550 dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
551 handle = ext4_journal_start(inode, dio_credits);
552 if (IS_ERR(handle)) {
553 ret = PTR_ERR(handle);
554 return ret;
555 }
556 started = 1;
557 }
558
559 ret = ext4_map_blocks(handle, inode, &map, flags);
560 if (ret > 0) {
561 map_bh(bh, inode->i_sb, map.m_pblk);
562 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
563 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
564 ret = 0;
565 }
566 if (started)
567 ext4_journal_stop(handle);
568 return ret;
569}
570
571int ext4_get_block(struct inode *inode, sector_t iblock,
572 struct buffer_head *bh, int create)
573{
574 return _ext4_get_block(inode, iblock, bh,
575 create ? EXT4_GET_BLOCKS_CREATE : 0);
576}
577
578/*
579 * `handle' can be NULL if create is zero
580 */
581struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
582 ext4_lblk_t block, int create, int *errp)
583{
584 struct ext4_map_blocks map;
585 struct buffer_head *bh;
586 int fatal = 0, err;
587
588 J_ASSERT(handle != NULL || create == 0);
589
590 map.m_lblk = block;
591 map.m_len = 1;
592 err = ext4_map_blocks(handle, inode, &map,
593 create ? EXT4_GET_BLOCKS_CREATE : 0);
594
595 if (err < 0)
596 *errp = err;
597 if (err <= 0)
598 return NULL;
599 *errp = 0;
600
601 bh = sb_getblk(inode->i_sb, map.m_pblk);
602 if (!bh) {
603 *errp = -EIO;
604 return NULL;
605 }
606 if (map.m_flags & EXT4_MAP_NEW) {
607 J_ASSERT(create != 0);
608 J_ASSERT(handle != NULL);
609
610 /*
611 * Now that we do not always journal data, we should
612 * keep in mind whether this should always journal the
613 * new buffer as metadata. For now, regular file
614 * writes use ext4_get_block instead, so it's not a
615 * problem.
616 */
617 lock_buffer(bh);
618 BUFFER_TRACE(bh, "call get_create_access");
619 fatal = ext4_journal_get_create_access(handle, bh);
620 if (!fatal && !buffer_uptodate(bh)) {
621 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
622 set_buffer_uptodate(bh);
623 }
624 unlock_buffer(bh);
625 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
626 err = ext4_handle_dirty_metadata(handle, inode, bh);
627 if (!fatal)
628 fatal = err;
629 } else {
630 BUFFER_TRACE(bh, "not a new buffer");
631 }
632 if (fatal) {
633 *errp = fatal;
634 brelse(bh);
635 bh = NULL;
636 }
637 return bh;
638}
639
640struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
641 ext4_lblk_t block, int create, int *err)
642{
643 struct buffer_head *bh;
644
645 bh = ext4_getblk(handle, inode, block, create, err);
646 if (!bh)
647 return bh;
648 if (buffer_uptodate(bh))
649 return bh;
650 ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
651 wait_on_buffer(bh);
652 if (buffer_uptodate(bh))
653 return bh;
654 put_bh(bh);
655 *err = -EIO;
656 return NULL;
657}
658
659static int walk_page_buffers(handle_t *handle,
660 struct buffer_head *head,
661 unsigned from,
662 unsigned to,
663 int *partial,
664 int (*fn)(handle_t *handle,
665 struct buffer_head *bh))
666{
667 struct buffer_head *bh;
668 unsigned block_start, block_end;
669 unsigned blocksize = head->b_size;
670 int err, ret = 0;
671 struct buffer_head *next;
672
673 for (bh = head, block_start = 0;
674 ret == 0 && (bh != head || !block_start);
675 block_start = block_end, bh = next) {
676 next = bh->b_this_page;
677 block_end = block_start + blocksize;
678 if (block_end <= from || block_start >= to) {
679 if (partial && !buffer_uptodate(bh))
680 *partial = 1;
681 continue;
682 }
683 err = (*fn)(handle, bh);
684 if (!ret)
685 ret = err;
686 }
687 return ret;
688}
689
690/*
691 * To preserve ordering, it is essential that the hole instantiation and
692 * the data write be encapsulated in a single transaction. We cannot
693 * close off a transaction and start a new one between the ext4_get_block()
694 * and the commit_write(). So doing the jbd2_journal_start at the start of
695 * prepare_write() is the right place.
696 *
697 * Also, this function can nest inside ext4_writepage() ->
698 * block_write_full_page(). In that case, we *know* that ext4_writepage()
699 * has generated enough buffer credits to do the whole page. So we won't
700 * block on the journal in that case, which is good, because the caller may
701 * be PF_MEMALLOC.
702 *
703 * By accident, ext4 can be reentered when a transaction is open via
704 * quota file writes. If we were to commit the transaction while thus
705 * reentered, there can be a deadlock - we would be holding a quota
706 * lock, and the commit would never complete if another thread had a
707 * transaction open and was blocking on the quota lock - a ranking
708 * violation.
709 *
710 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
711 * will _not_ run commit under these circumstances because handle->h_ref
712 * is elevated. We'll still have enough credits for the tiny quotafile
713 * write.
714 */
715static int do_journal_get_write_access(handle_t *handle,
716 struct buffer_head *bh)
717{
718 int dirty = buffer_dirty(bh);
719 int ret;
720
721 if (!buffer_mapped(bh) || buffer_freed(bh))
722 return 0;
723 /*
724 * __block_write_begin() could have dirtied some buffers. Clean
725 * the dirty bit as jbd2_journal_get_write_access() could complain
726 * otherwise about fs integrity issues. Setting of the dirty bit
727 * by __block_write_begin() isn't a real problem here as we clear
728 * the bit before releasing a page lock and thus writeback cannot
729 * ever write the buffer.
730 */
731 if (dirty)
732 clear_buffer_dirty(bh);
733 ret = ext4_journal_get_write_access(handle, bh);
734 if (!ret && dirty)
735 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
736 return ret;
737}
738
739static int ext4_get_block_write(struct inode *inode, sector_t iblock,
740 struct buffer_head *bh_result, int create);
741static int ext4_write_begin(struct file *file, struct address_space *mapping,
742 loff_t pos, unsigned len, unsigned flags,
743 struct page **pagep, void **fsdata)
744{
745 struct inode *inode = mapping->host;
746 int ret, needed_blocks;
747 handle_t *handle;
748 int retries = 0;
749 struct page *page;
750 pgoff_t index;
751 unsigned from, to;
752
753 trace_ext4_write_begin(inode, pos, len, flags);
754 /*
755 * Reserve one block more for addition to orphan list in case
756 * we allocate blocks but write fails for some reason
757 */
758 needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
759 index = pos >> PAGE_CACHE_SHIFT;
760 from = pos & (PAGE_CACHE_SIZE - 1);
761 to = from + len;
762
763retry:
764 handle = ext4_journal_start(inode, needed_blocks);
765 if (IS_ERR(handle)) {
766 ret = PTR_ERR(handle);
767 goto out;
768 }
769
770 /* We cannot recurse into the filesystem as the transaction is already
771 * started */
772 flags |= AOP_FLAG_NOFS;
773
774 page = grab_cache_page_write_begin(mapping, index, flags);
775 if (!page) {
776 ext4_journal_stop(handle);
777 ret = -ENOMEM;
778 goto out;
779 }
780 *pagep = page;
781
782 if (ext4_should_dioread_nolock(inode))
783 ret = __block_write_begin(page, pos, len, ext4_get_block_write);
784 else
785 ret = __block_write_begin(page, pos, len, ext4_get_block);
786
787 if (!ret && ext4_should_journal_data(inode)) {
788 ret = walk_page_buffers(handle, page_buffers(page),
789 from, to, NULL, do_journal_get_write_access);
790 }
791
792 if (ret) {
793 unlock_page(page);
794 page_cache_release(page);
795 /*
796 * __block_write_begin may have instantiated a few blocks
797 * outside i_size. Trim these off again. Don't need
798 * i_size_read because we hold i_mutex.
799 *
800 * Add inode to orphan list in case we crash before
801 * truncate finishes
802 */
803 if (pos + len > inode->i_size && ext4_can_truncate(inode))
804 ext4_orphan_add(handle, inode);
805
806 ext4_journal_stop(handle);
807 if (pos + len > inode->i_size) {
808 ext4_truncate_failed_write(inode);
809 /*
810 * If truncate failed early the inode might
811 * still be on the orphan list; we need to
812 * make sure the inode is removed from the
813 * orphan list in that case.
814 */
815 if (inode->i_nlink)
816 ext4_orphan_del(NULL, inode);
817 }
818 }
819
820 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
821 goto retry;
822out:
823 return ret;
824}
825
826/* For write_end() in data=journal mode */
827static int write_end_fn(handle_t *handle, struct buffer_head *bh)
828{
829 if (!buffer_mapped(bh) || buffer_freed(bh))
830 return 0;
831 set_buffer_uptodate(bh);
832 return ext4_handle_dirty_metadata(handle, NULL, bh);
833}
834
835static int ext4_generic_write_end(struct file *file,
836 struct address_space *mapping,
837 loff_t pos, unsigned len, unsigned copied,
838 struct page *page, void *fsdata)
839{
840 int i_size_changed = 0;
841 struct inode *inode = mapping->host;
842 handle_t *handle = ext4_journal_current_handle();
843
844 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
845
846 /*
847 * No need to use i_size_read() here, the i_size
848 * cannot change under us because we hold i_mutex.
849 *
850 * But it's important to update i_size while still holding page lock:
851 * page writeout could otherwise come in and zero beyond i_size.
852 */
853 if (pos + copied > inode->i_size) {
854 i_size_write(inode, pos + copied);
855 i_size_changed = 1;
856 }
857
858 if (pos + copied > EXT4_I(inode)->i_disksize) {
859 /* We need to mark inode dirty even if
860 * new_i_size is less that inode->i_size
861 * bu greater than i_disksize.(hint delalloc)
862 */
863 ext4_update_i_disksize(inode, (pos + copied));
864 i_size_changed = 1;
865 }
866 unlock_page(page);
867 page_cache_release(page);
868
869 /*
870 * Don't mark the inode dirty under page lock. First, it unnecessarily
871 * makes the holding time of page lock longer. Second, it forces lock
872 * ordering of page lock and transaction start for journaling
873 * filesystems.
874 */
875 if (i_size_changed)
876 ext4_mark_inode_dirty(handle, inode);
877
878 return copied;
879}
880
881/*
882 * We need to pick up the new inode size which generic_commit_write gave us
883 * `file' can be NULL - eg, when called from page_symlink().
884 *
885 * ext4 never places buffers on inode->i_mapping->private_list. metadata
886 * buffers are managed internally.
887 */
888static int ext4_ordered_write_end(struct file *file,
889 struct address_space *mapping,
890 loff_t pos, unsigned len, unsigned copied,
891 struct page *page, void *fsdata)
892{
893 handle_t *handle = ext4_journal_current_handle();
894 struct inode *inode = mapping->host;
895 int ret = 0, ret2;
896
897 trace_ext4_ordered_write_end(inode, pos, len, copied);
898 ret = ext4_jbd2_file_inode(handle, inode);
899
900 if (ret == 0) {
901 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
902 page, fsdata);
903 copied = ret2;
904 if (pos + len > inode->i_size && ext4_can_truncate(inode))
905 /* if we have allocated more blocks and copied
906 * less. We will have blocks allocated outside
907 * inode->i_size. So truncate them
908 */
909 ext4_orphan_add(handle, inode);
910 if (ret2 < 0)
911 ret = ret2;
912 }
913 ret2 = ext4_journal_stop(handle);
914 if (!ret)
915 ret = ret2;
916
917 if (pos + len > inode->i_size) {
918 ext4_truncate_failed_write(inode);
919 /*
920 * If truncate failed early the inode might still be
921 * on the orphan list; we need to make sure the inode
922 * is removed from the orphan list in that case.
923 */
924 if (inode->i_nlink)
925 ext4_orphan_del(NULL, inode);
926 }
927
928
929 return ret ? ret : copied;
930}
931
932static int ext4_writeback_write_end(struct file *file,
933 struct address_space *mapping,
934 loff_t pos, unsigned len, unsigned copied,
935 struct page *page, void *fsdata)
936{
937 handle_t *handle = ext4_journal_current_handle();
938 struct inode *inode = mapping->host;
939 int ret = 0, ret2;
940
941 trace_ext4_writeback_write_end(inode, pos, len, copied);
942 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
943 page, fsdata);
944 copied = ret2;
945 if (pos + len > inode->i_size && ext4_can_truncate(inode))
946 /* if we have allocated more blocks and copied
947 * less. We will have blocks allocated outside
948 * inode->i_size. So truncate them
949 */
950 ext4_orphan_add(handle, inode);
951
952 if (ret2 < 0)
953 ret = ret2;
954
955 ret2 = ext4_journal_stop(handle);
956 if (!ret)
957 ret = ret2;
958
959 if (pos + len > inode->i_size) {
960 ext4_truncate_failed_write(inode);
961 /*
962 * If truncate failed early the inode might still be
963 * on the orphan list; we need to make sure the inode
964 * is removed from the orphan list in that case.
965 */
966 if (inode->i_nlink)
967 ext4_orphan_del(NULL, inode);
968 }
969
970 return ret ? ret : copied;
971}
972
973static int ext4_journalled_write_end(struct file *file,
974 struct address_space *mapping,
975 loff_t pos, unsigned len, unsigned copied,
976 struct page *page, void *fsdata)
977{
978 handle_t *handle = ext4_journal_current_handle();
979 struct inode *inode = mapping->host;
980 int ret = 0, ret2;
981 int partial = 0;
982 unsigned from, to;
983 loff_t new_i_size;
984
985 trace_ext4_journalled_write_end(inode, pos, len, copied);
986 from = pos & (PAGE_CACHE_SIZE - 1);
987 to = from + len;
988
989 BUG_ON(!ext4_handle_valid(handle));
990
991 if (copied < len) {
992 if (!PageUptodate(page))
993 copied = 0;
994 page_zero_new_buffers(page, from+copied, to);
995 }
996
997 ret = walk_page_buffers(handle, page_buffers(page), from,
998 to, &partial, write_end_fn);
999 if (!partial)
1000 SetPageUptodate(page);
1001 new_i_size = pos + copied;
1002 if (new_i_size > inode->i_size)
1003 i_size_write(inode, pos+copied);
1004 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1005 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1006 if (new_i_size > EXT4_I(inode)->i_disksize) {
1007 ext4_update_i_disksize(inode, new_i_size);
1008 ret2 = ext4_mark_inode_dirty(handle, inode);
1009 if (!ret)
1010 ret = ret2;
1011 }
1012
1013 unlock_page(page);
1014 page_cache_release(page);
1015 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1016 /* if we have allocated more blocks and copied
1017 * less. We will have blocks allocated outside
1018 * inode->i_size. So truncate them
1019 */
1020 ext4_orphan_add(handle, inode);
1021
1022 ret2 = ext4_journal_stop(handle);
1023 if (!ret)
1024 ret = ret2;
1025 if (pos + len > inode->i_size) {
1026 ext4_truncate_failed_write(inode);
1027 /*
1028 * If truncate failed early the inode might still be
1029 * on the orphan list; we need to make sure the inode
1030 * is removed from the orphan list in that case.
1031 */
1032 if (inode->i_nlink)
1033 ext4_orphan_del(NULL, inode);
1034 }
1035
1036 return ret ? ret : copied;
1037}
1038
1039/*
1040 * Reserve a single block located at lblock
1041 */
1042static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
1043{
1044 int retries = 0;
1045 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1046 struct ext4_inode_info *ei = EXT4_I(inode);
1047 unsigned long md_needed;
1048 int ret;
1049
1050 /*
1051 * recalculate the amount of metadata blocks to reserve
1052 * in order to allocate nrblocks
1053 * worse case is one extent per block
1054 */
1055repeat:
1056 spin_lock(&ei->i_block_reservation_lock);
1057 md_needed = ext4_calc_metadata_amount(inode, lblock);
1058 trace_ext4_da_reserve_space(inode, md_needed);
1059 spin_unlock(&ei->i_block_reservation_lock);
1060
1061 /*
1062 * We will charge metadata quota at writeout time; this saves
1063 * us from metadata over-estimation, though we may go over by
1064 * a small amount in the end. Here we just reserve for data.
1065 */
1066 ret = dquot_reserve_block(inode, 1);
1067 if (ret)
1068 return ret;
1069 /*
1070 * We do still charge estimated metadata to the sb though;
1071 * we cannot afford to run out of free blocks.
1072 */
1073 if (ext4_claim_free_blocks(sbi, md_needed + 1, 0)) {
1074 dquot_release_reservation_block(inode, 1);
1075 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1076 yield();
1077 goto repeat;
1078 }
1079 return -ENOSPC;
1080 }
1081 spin_lock(&ei->i_block_reservation_lock);
1082 ei->i_reserved_data_blocks++;
1083 ei->i_reserved_meta_blocks += md_needed;
1084 spin_unlock(&ei->i_block_reservation_lock);
1085
1086 return 0; /* success */
1087}
1088
1089static void ext4_da_release_space(struct inode *inode, int to_free)
1090{
1091 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1092 struct ext4_inode_info *ei = EXT4_I(inode);
1093
1094 if (!to_free)
1095 return; /* Nothing to release, exit */
1096
1097 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1098
1099 trace_ext4_da_release_space(inode, to_free);
1100 if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1101 /*
1102 * if there aren't enough reserved blocks, then the
1103 * counter is messed up somewhere. Since this
1104 * function is called from invalidate page, it's
1105 * harmless to return without any action.
1106 */
1107 ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
1108 "ino %lu, to_free %d with only %d reserved "
1109 "data blocks\n", inode->i_ino, to_free,
1110 ei->i_reserved_data_blocks);
1111 WARN_ON(1);
1112 to_free = ei->i_reserved_data_blocks;
1113 }
1114 ei->i_reserved_data_blocks -= to_free;
1115
1116 if (ei->i_reserved_data_blocks == 0) {
1117 /*
1118 * We can release all of the reserved metadata blocks
1119 * only when we have written all of the delayed
1120 * allocation blocks.
1121 */
1122 percpu_counter_sub(&sbi->s_dirtyblocks_counter,
1123 ei->i_reserved_meta_blocks);
1124 ei->i_reserved_meta_blocks = 0;
1125 ei->i_da_metadata_calc_len = 0;
1126 }
1127
1128 /* update fs dirty data blocks counter */
1129 percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free);
1130
1131 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1132
1133 dquot_release_reservation_block(inode, to_free);
1134}
1135
1136static void ext4_da_page_release_reservation(struct page *page,
1137 unsigned long offset)
1138{
1139 int to_release = 0;
1140 struct buffer_head *head, *bh;
1141 unsigned int curr_off = 0;
1142
1143 head = page_buffers(page);
1144 bh = head;
1145 do {
1146 unsigned int next_off = curr_off + bh->b_size;
1147
1148 if ((offset <= curr_off) && (buffer_delay(bh))) {
1149 to_release++;
1150 clear_buffer_delay(bh);
1151 }
1152 curr_off = next_off;
1153 } while ((bh = bh->b_this_page) != head);
1154 ext4_da_release_space(page->mapping->host, to_release);
1155}
1156
1157/*
1158 * Delayed allocation stuff
1159 */
1160
1161/*
1162 * mpage_da_submit_io - walks through extent of pages and try to write
1163 * them with writepage() call back
1164 *
1165 * @mpd->inode: inode
1166 * @mpd->first_page: first page of the extent
1167 * @mpd->next_page: page after the last page of the extent
1168 *
1169 * By the time mpage_da_submit_io() is called we expect all blocks
1170 * to be allocated. this may be wrong if allocation failed.
1171 *
1172 * As pages are already locked by write_cache_pages(), we can't use it
1173 */
1174static int mpage_da_submit_io(struct mpage_da_data *mpd,
1175 struct ext4_map_blocks *map)
1176{
1177 struct pagevec pvec;
1178 unsigned long index, end;
1179 int ret = 0, err, nr_pages, i;
1180 struct inode *inode = mpd->inode;
1181 struct address_space *mapping = inode->i_mapping;
1182 loff_t size = i_size_read(inode);
1183 unsigned int len, block_start;
1184 struct buffer_head *bh, *page_bufs = NULL;
1185 int journal_data = ext4_should_journal_data(inode);
1186 sector_t pblock = 0, cur_logical = 0;
1187 struct ext4_io_submit io_submit;
1188
1189 BUG_ON(mpd->next_page <= mpd->first_page);
1190 memset(&io_submit, 0, sizeof(io_submit));
1191 /*
1192 * We need to start from the first_page to the next_page - 1
1193 * to make sure we also write the mapped dirty buffer_heads.
1194 * If we look at mpd->b_blocknr we would only be looking
1195 * at the currently mapped buffer_heads.
1196 */
1197 index = mpd->first_page;
1198 end = mpd->next_page - 1;
1199
1200 pagevec_init(&pvec, 0);
1201 while (index <= end) {
1202 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1203 if (nr_pages == 0)
1204 break;
1205 for (i = 0; i < nr_pages; i++) {
1206 int commit_write = 0, skip_page = 0;
1207 struct page *page = pvec.pages[i];
1208
1209 index = page->index;
1210 if (index > end)
1211 break;
1212
1213 if (index == size >> PAGE_CACHE_SHIFT)
1214 len = size & ~PAGE_CACHE_MASK;
1215 else
1216 len = PAGE_CACHE_SIZE;
1217 if (map) {
1218 cur_logical = index << (PAGE_CACHE_SHIFT -
1219 inode->i_blkbits);
1220 pblock = map->m_pblk + (cur_logical -
1221 map->m_lblk);
1222 }
1223 index++;
1224
1225 BUG_ON(!PageLocked(page));
1226 BUG_ON(PageWriteback(page));
1227
1228 /*
1229 * If the page does not have buffers (for
1230 * whatever reason), try to create them using
1231 * __block_write_begin. If this fails,
1232 * skip the page and move on.
1233 */
1234 if (!page_has_buffers(page)) {
1235 if (__block_write_begin(page, 0, len,
1236 noalloc_get_block_write)) {
1237 skip_page:
1238 unlock_page(page);
1239 continue;
1240 }
1241 commit_write = 1;
1242 }
1243
1244 bh = page_bufs = page_buffers(page);
1245 block_start = 0;
1246 do {
1247 if (!bh)
1248 goto skip_page;
1249 if (map && (cur_logical >= map->m_lblk) &&
1250 (cur_logical <= (map->m_lblk +
1251 (map->m_len - 1)))) {
1252 if (buffer_delay(bh)) {
1253 clear_buffer_delay(bh);
1254 bh->b_blocknr = pblock;
1255 }
1256 if (buffer_unwritten(bh) ||
1257 buffer_mapped(bh))
1258 BUG_ON(bh->b_blocknr != pblock);
1259 if (map->m_flags & EXT4_MAP_UNINIT)
1260 set_buffer_uninit(bh);
1261 clear_buffer_unwritten(bh);
1262 }
1263
1264 /* skip page if block allocation undone */
1265 if (buffer_delay(bh) || buffer_unwritten(bh))
1266 skip_page = 1;
1267 bh = bh->b_this_page;
1268 block_start += bh->b_size;
1269 cur_logical++;
1270 pblock++;
1271 } while (bh != page_bufs);
1272
1273 if (skip_page)
1274 goto skip_page;
1275
1276 if (commit_write)
1277 /* mark the buffer_heads as dirty & uptodate */
1278 block_commit_write(page, 0, len);
1279
1280 clear_page_dirty_for_io(page);
1281 /*
1282 * Delalloc doesn't support data journalling,
1283 * but eventually maybe we'll lift this
1284 * restriction.
1285 */
1286 if (unlikely(journal_data && PageChecked(page)))
1287 err = __ext4_journalled_writepage(page, len);
1288 else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT))
1289 err = ext4_bio_write_page(&io_submit, page,
1290 len, mpd->wbc);
1291 else if (buffer_uninit(page_bufs)) {
1292 ext4_set_bh_endio(page_bufs, inode);
1293 err = block_write_full_page_endio(page,
1294 noalloc_get_block_write,
1295 mpd->wbc, ext4_end_io_buffer_write);
1296 } else
1297 err = block_write_full_page(page,
1298 noalloc_get_block_write, mpd->wbc);
1299
1300 if (!err)
1301 mpd->pages_written++;
1302 /*
1303 * In error case, we have to continue because
1304 * remaining pages are still locked
1305 */
1306 if (ret == 0)
1307 ret = err;
1308 }
1309 pagevec_release(&pvec);
1310 }
1311 ext4_io_submit(&io_submit);
1312 return ret;
1313}
1314
1315static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
1316{
1317 int nr_pages, i;
1318 pgoff_t index, end;
1319 struct pagevec pvec;
1320 struct inode *inode = mpd->inode;
1321 struct address_space *mapping = inode->i_mapping;
1322
1323 index = mpd->first_page;
1324 end = mpd->next_page - 1;
1325 while (index <= end) {
1326 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1327 if (nr_pages == 0)
1328 break;
1329 for (i = 0; i < nr_pages; i++) {
1330 struct page *page = pvec.pages[i];
1331 if (page->index > end)
1332 break;
1333 BUG_ON(!PageLocked(page));
1334 BUG_ON(PageWriteback(page));
1335 block_invalidatepage(page, 0);
1336 ClearPageUptodate(page);
1337 unlock_page(page);
1338 }
1339 index = pvec.pages[nr_pages - 1]->index + 1;
1340 pagevec_release(&pvec);
1341 }
1342 return;
1343}
1344
1345static void ext4_print_free_blocks(struct inode *inode)
1346{
1347 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1348 printk(KERN_CRIT "Total free blocks count %lld\n",
1349 ext4_count_free_blocks(inode->i_sb));
1350 printk(KERN_CRIT "Free/Dirty block details\n");
1351 printk(KERN_CRIT "free_blocks=%lld\n",
1352 (long long) percpu_counter_sum(&sbi->s_freeblocks_counter));
1353 printk(KERN_CRIT "dirty_blocks=%lld\n",
1354 (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
1355 printk(KERN_CRIT "Block reservation details\n");
1356 printk(KERN_CRIT "i_reserved_data_blocks=%u\n",
1357 EXT4_I(inode)->i_reserved_data_blocks);
1358 printk(KERN_CRIT "i_reserved_meta_blocks=%u\n",
1359 EXT4_I(inode)->i_reserved_meta_blocks);
1360 return;
1361}
1362
1363/*
1364 * mpage_da_map_and_submit - go through given space, map them
1365 * if necessary, and then submit them for I/O
1366 *
1367 * @mpd - bh describing space
1368 *
1369 * The function skips space we know is already mapped to disk blocks.
1370 *
1371 */
1372static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
1373{
1374 int err, blks, get_blocks_flags;
1375 struct ext4_map_blocks map, *mapp = NULL;
1376 sector_t next = mpd->b_blocknr;
1377 unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
1378 loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
1379 handle_t *handle = NULL;
1380
1381 /*
1382 * If the blocks are mapped already, or we couldn't accumulate
1383 * any blocks, then proceed immediately to the submission stage.
1384 */
1385 if ((mpd->b_size == 0) ||
1386 ((mpd->b_state & (1 << BH_Mapped)) &&
1387 !(mpd->b_state & (1 << BH_Delay)) &&
1388 !(mpd->b_state & (1 << BH_Unwritten))))
1389 goto submit_io;
1390
1391 handle = ext4_journal_current_handle();
1392 BUG_ON(!handle);
1393
1394 /*
1395 * Call ext4_map_blocks() to allocate any delayed allocation
1396 * blocks, or to convert an uninitialized extent to be
1397 * initialized (in the case where we have written into
1398 * one or more preallocated blocks).
1399 *
1400 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
1401 * indicate that we are on the delayed allocation path. This
1402 * affects functions in many different parts of the allocation
1403 * call path. This flag exists primarily because we don't
1404 * want to change *many* call functions, so ext4_map_blocks()
1405 * will set the EXT4_STATE_DELALLOC_RESERVED flag once the
1406 * inode's allocation semaphore is taken.
1407 *
1408 * If the blocks in questions were delalloc blocks, set
1409 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
1410 * variables are updated after the blocks have been allocated.
1411 */
1412 map.m_lblk = next;
1413 map.m_len = max_blocks;
1414 get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
1415 if (ext4_should_dioread_nolock(mpd->inode))
1416 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
1417 if (mpd->b_state & (1 << BH_Delay))
1418 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
1419
1420 blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
1421 if (blks < 0) {
1422 struct super_block *sb = mpd->inode->i_sb;
1423
1424 err = blks;
1425 /*
1426 * If get block returns EAGAIN or ENOSPC and there
1427 * appears to be free blocks we will just let
1428 * mpage_da_submit_io() unlock all of the pages.
1429 */
1430 if (err == -EAGAIN)
1431 goto submit_io;
1432
1433 if (err == -ENOSPC &&
1434 ext4_count_free_blocks(sb)) {
1435 mpd->retval = err;
1436 goto submit_io;
1437 }
1438
1439 /*
1440 * get block failure will cause us to loop in
1441 * writepages, because a_ops->writepage won't be able
1442 * to make progress. The page will be redirtied by
1443 * writepage and writepages will again try to write
1444 * the same.
1445 */
1446 if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) {
1447 ext4_msg(sb, KERN_CRIT,
1448 "delayed block allocation failed for inode %lu "
1449 "at logical offset %llu with max blocks %zd "
1450 "with error %d", mpd->inode->i_ino,
1451 (unsigned long long) next,
1452 mpd->b_size >> mpd->inode->i_blkbits, err);
1453 ext4_msg(sb, KERN_CRIT,
1454 "This should not happen!! Data will be lost\n");
1455 if (err == -ENOSPC)
1456 ext4_print_free_blocks(mpd->inode);
1457 }
1458 /* invalidate all the pages */
1459 ext4_da_block_invalidatepages(mpd);
1460
1461 /* Mark this page range as having been completed */
1462 mpd->io_done = 1;
1463 return;
1464 }
1465 BUG_ON(blks == 0);
1466
1467 mapp = ↦
1468 if (map.m_flags & EXT4_MAP_NEW) {
1469 struct block_device *bdev = mpd->inode->i_sb->s_bdev;
1470 int i;
1471
1472 for (i = 0; i < map.m_len; i++)
1473 unmap_underlying_metadata(bdev, map.m_pblk + i);
1474 }
1475
1476 if (ext4_should_order_data(mpd->inode)) {
1477 err = ext4_jbd2_file_inode(handle, mpd->inode);
1478 if (err)
1479 /* This only happens if the journal is aborted */
1480 return;
1481 }
1482
1483 /*
1484 * Update on-disk size along with block allocation.
1485 */
1486 disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
1487 if (disksize > i_size_read(mpd->inode))
1488 disksize = i_size_read(mpd->inode);
1489 if (disksize > EXT4_I(mpd->inode)->i_disksize) {
1490 ext4_update_i_disksize(mpd->inode, disksize);
1491 err = ext4_mark_inode_dirty(handle, mpd->inode);
1492 if (err)
1493 ext4_error(mpd->inode->i_sb,
1494 "Failed to mark inode %lu dirty",
1495 mpd->inode->i_ino);
1496 }
1497
1498submit_io:
1499 mpage_da_submit_io(mpd, mapp);
1500 mpd->io_done = 1;
1501}
1502
1503#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
1504 (1 << BH_Delay) | (1 << BH_Unwritten))
1505
1506/*
1507 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
1508 *
1509 * @mpd->lbh - extent of blocks
1510 * @logical - logical number of the block in the file
1511 * @bh - bh of the block (used to access block's state)
1512 *
1513 * the function is used to collect contig. blocks in same state
1514 */
1515static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
1516 sector_t logical, size_t b_size,
1517 unsigned long b_state)
1518{
1519 sector_t next;
1520 int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
1521
1522 /*
1523 * XXX Don't go larger than mballoc is willing to allocate
1524 * This is a stopgap solution. We eventually need to fold
1525 * mpage_da_submit_io() into this function and then call
1526 * ext4_map_blocks() multiple times in a loop
1527 */
1528 if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize)
1529 goto flush_it;
1530
1531 /* check if thereserved journal credits might overflow */
1532 if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) {
1533 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
1534 /*
1535 * With non-extent format we are limited by the journal
1536 * credit available. Total credit needed to insert
1537 * nrblocks contiguous blocks is dependent on the
1538 * nrblocks. So limit nrblocks.
1539 */
1540 goto flush_it;
1541 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
1542 EXT4_MAX_TRANS_DATA) {
1543 /*
1544 * Adding the new buffer_head would make it cross the
1545 * allowed limit for which we have journal credit
1546 * reserved. So limit the new bh->b_size
1547 */
1548 b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
1549 mpd->inode->i_blkbits;
1550 /* we will do mpage_da_submit_io in the next loop */
1551 }
1552 }
1553 /*
1554 * First block in the extent
1555 */
1556 if (mpd->b_size == 0) {
1557 mpd->b_blocknr = logical;
1558 mpd->b_size = b_size;
1559 mpd->b_state = b_state & BH_FLAGS;
1560 return;
1561 }
1562
1563 next = mpd->b_blocknr + nrblocks;
1564 /*
1565 * Can we merge the block to our big extent?
1566 */
1567 if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
1568 mpd->b_size += b_size;
1569 return;
1570 }
1571
1572flush_it:
1573 /*
1574 * We couldn't merge the block to our extent, so we
1575 * need to flush current extent and start new one
1576 */
1577 mpage_da_map_and_submit(mpd);
1578 return;
1579}
1580
1581static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1582{
1583 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1584}
1585
1586/*
1587 * This is a special get_blocks_t callback which is used by
1588 * ext4_da_write_begin(). It will either return mapped block or
1589 * reserve space for a single block.
1590 *
1591 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1592 * We also have b_blocknr = -1 and b_bdev initialized properly
1593 *
1594 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1595 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1596 * initialized properly.
1597 */
1598static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1599 struct buffer_head *bh, int create)
1600{
1601 struct ext4_map_blocks map;
1602 int ret = 0;
1603 sector_t invalid_block = ~((sector_t) 0xffff);
1604
1605 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1606 invalid_block = ~0;
1607
1608 BUG_ON(create == 0);
1609 BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1610
1611 map.m_lblk = iblock;
1612 map.m_len = 1;
1613
1614 /*
1615 * first, we need to know whether the block is allocated already
1616 * preallocated blocks are unmapped but should treated
1617 * the same as allocated blocks.
1618 */
1619 ret = ext4_map_blocks(NULL, inode, &map, 0);
1620 if (ret < 0)
1621 return ret;
1622 if (ret == 0) {
1623 if (buffer_delay(bh))
1624 return 0; /* Not sure this could or should happen */
1625 /*
1626 * XXX: __block_write_begin() unmaps passed block, is it OK?
1627 */
1628 ret = ext4_da_reserve_space(inode, iblock);
1629 if (ret)
1630 /* not enough space to reserve */
1631 return ret;
1632
1633 map_bh(bh, inode->i_sb, invalid_block);
1634 set_buffer_new(bh);
1635 set_buffer_delay(bh);
1636 return 0;
1637 }
1638
1639 map_bh(bh, inode->i_sb, map.m_pblk);
1640 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
1641
1642 if (buffer_unwritten(bh)) {
1643 /* A delayed write to unwritten bh should be marked
1644 * new and mapped. Mapped ensures that we don't do
1645 * get_block multiple times when we write to the same
1646 * offset and new ensures that we do proper zero out
1647 * for partial write.
1648 */
1649 set_buffer_new(bh);
1650 set_buffer_mapped(bh);
1651 }
1652 return 0;
1653}
1654
1655/*
1656 * This function is used as a standard get_block_t calback function
1657 * when there is no desire to allocate any blocks. It is used as a
1658 * callback function for block_write_begin() and block_write_full_page().
1659 * These functions should only try to map a single block at a time.
1660 *
1661 * Since this function doesn't do block allocations even if the caller
1662 * requests it by passing in create=1, it is critically important that
1663 * any caller checks to make sure that any buffer heads are returned
1664 * by this function are either all already mapped or marked for
1665 * delayed allocation before calling block_write_full_page(). Otherwise,
1666 * b_blocknr could be left unitialized, and the page write functions will
1667 * be taken by surprise.
1668 */
1669static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
1670 struct buffer_head *bh_result, int create)
1671{
1672 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
1673 return _ext4_get_block(inode, iblock, bh_result, 0);
1674}
1675
1676static int bget_one(handle_t *handle, struct buffer_head *bh)
1677{
1678 get_bh(bh);
1679 return 0;
1680}
1681
1682static int bput_one(handle_t *handle, struct buffer_head *bh)
1683{
1684 put_bh(bh);
1685 return 0;
1686}
1687
1688static int __ext4_journalled_writepage(struct page *page,
1689 unsigned int len)
1690{
1691 struct address_space *mapping = page->mapping;
1692 struct inode *inode = mapping->host;
1693 struct buffer_head *page_bufs;
1694 handle_t *handle = NULL;
1695 int ret = 0;
1696 int err;
1697
1698 ClearPageChecked(page);
1699 page_bufs = page_buffers(page);
1700 BUG_ON(!page_bufs);
1701 walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
1702 /* As soon as we unlock the page, it can go away, but we have
1703 * references to buffers so we are safe */
1704 unlock_page(page);
1705
1706 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1707 if (IS_ERR(handle)) {
1708 ret = PTR_ERR(handle);
1709 goto out;
1710 }
1711
1712 BUG_ON(!ext4_handle_valid(handle));
1713
1714 ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
1715 do_journal_get_write_access);
1716
1717 err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
1718 write_end_fn);
1719 if (ret == 0)
1720 ret = err;
1721 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1722 err = ext4_journal_stop(handle);
1723 if (!ret)
1724 ret = err;
1725
1726 walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
1727 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1728out:
1729 return ret;
1730}
1731
1732static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
1733static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
1734
1735/*
1736 * Note that we don't need to start a transaction unless we're journaling data
1737 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1738 * need to file the inode to the transaction's list in ordered mode because if
1739 * we are writing back data added by write(), the inode is already there and if
1740 * we are writing back data modified via mmap(), no one guarantees in which
1741 * transaction the data will hit the disk. In case we are journaling data, we
1742 * cannot start transaction directly because transaction start ranks above page
1743 * lock so we have to do some magic.
1744 *
1745 * This function can get called via...
1746 * - ext4_da_writepages after taking page lock (have journal handle)
1747 * - journal_submit_inode_data_buffers (no journal handle)
1748 * - shrink_page_list via pdflush (no journal handle)
1749 * - grab_page_cache when doing write_begin (have journal handle)
1750 *
1751 * We don't do any block allocation in this function. If we have page with
1752 * multiple blocks we need to write those buffer_heads that are mapped. This
1753 * is important for mmaped based write. So if we do with blocksize 1K
1754 * truncate(f, 1024);
1755 * a = mmap(f, 0, 4096);
1756 * a[0] = 'a';
1757 * truncate(f, 4096);
1758 * we have in the page first buffer_head mapped via page_mkwrite call back
1759 * but other bufer_heads would be unmapped but dirty(dirty done via the
1760 * do_wp_page). So writepage should write the first block. If we modify
1761 * the mmap area beyond 1024 we will again get a page_fault and the
1762 * page_mkwrite callback will do the block allocation and mark the
1763 * buffer_heads mapped.
1764 *
1765 * We redirty the page if we have any buffer_heads that is either delay or
1766 * unwritten in the page.
1767 *
1768 * We can get recursively called as show below.
1769 *
1770 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1771 * ext4_writepage()
1772 *
1773 * But since we don't do any block allocation we should not deadlock.
1774 * Page also have the dirty flag cleared so we don't get recurive page_lock.
1775 */
1776static int ext4_writepage(struct page *page,
1777 struct writeback_control *wbc)
1778{
1779 int ret = 0, commit_write = 0;
1780 loff_t size;
1781 unsigned int len;
1782 struct buffer_head *page_bufs = NULL;
1783 struct inode *inode = page->mapping->host;
1784
1785 trace_ext4_writepage(page);
1786 size = i_size_read(inode);
1787 if (page->index == size >> PAGE_CACHE_SHIFT)
1788 len = size & ~PAGE_CACHE_MASK;
1789 else
1790 len = PAGE_CACHE_SIZE;
1791
1792 /*
1793 * If the page does not have buffers (for whatever reason),
1794 * try to create them using __block_write_begin. If this
1795 * fails, redirty the page and move on.
1796 */
1797 if (!page_has_buffers(page)) {
1798 if (__block_write_begin(page, 0, len,
1799 noalloc_get_block_write)) {
1800 redirty_page:
1801 redirty_page_for_writepage(wbc, page);
1802 unlock_page(page);
1803 return 0;
1804 }
1805 commit_write = 1;
1806 }
1807 page_bufs = page_buffers(page);
1808 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
1809 ext4_bh_delay_or_unwritten)) {
1810 /*
1811 * We don't want to do block allocation, so redirty
1812 * the page and return. We may reach here when we do
1813 * a journal commit via journal_submit_inode_data_buffers.
1814 * We can also reach here via shrink_page_list
1815 */
1816 goto redirty_page;
1817 }
1818 if (commit_write)
1819 /* now mark the buffer_heads as dirty and uptodate */
1820 block_commit_write(page, 0, len);
1821
1822 if (PageChecked(page) && ext4_should_journal_data(inode))
1823 /*
1824 * It's mmapped pagecache. Add buffers and journal it. There
1825 * doesn't seem much point in redirtying the page here.
1826 */
1827 return __ext4_journalled_writepage(page, len);
1828
1829 if (buffer_uninit(page_bufs)) {
1830 ext4_set_bh_endio(page_bufs, inode);
1831 ret = block_write_full_page_endio(page, noalloc_get_block_write,
1832 wbc, ext4_end_io_buffer_write);
1833 } else
1834 ret = block_write_full_page(page, noalloc_get_block_write,
1835 wbc);
1836
1837 return ret;
1838}
1839
1840/*
1841 * This is called via ext4_da_writepages() to
1842 * calculate the total number of credits to reserve to fit
1843 * a single extent allocation into a single transaction,
1844 * ext4_da_writpeages() will loop calling this before
1845 * the block allocation.
1846 */
1847
1848static int ext4_da_writepages_trans_blocks(struct inode *inode)
1849{
1850 int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
1851
1852 /*
1853 * With non-extent format the journal credit needed to
1854 * insert nrblocks contiguous block is dependent on
1855 * number of contiguous block. So we will limit
1856 * number of contiguous block to a sane value
1857 */
1858 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
1859 (max_blocks > EXT4_MAX_TRANS_DATA))
1860 max_blocks = EXT4_MAX_TRANS_DATA;
1861
1862 return ext4_chunk_trans_blocks(inode, max_blocks);
1863}
1864
1865/*
1866 * write_cache_pages_da - walk the list of dirty pages of the given
1867 * address space and accumulate pages that need writing, and call
1868 * mpage_da_map_and_submit to map a single contiguous memory region
1869 * and then write them.
1870 */
1871static int write_cache_pages_da(struct address_space *mapping,
1872 struct writeback_control *wbc,
1873 struct mpage_da_data *mpd,
1874 pgoff_t *done_index)
1875{
1876 struct buffer_head *bh, *head;
1877 struct inode *inode = mapping->host;
1878 struct pagevec pvec;
1879 unsigned int nr_pages;
1880 sector_t logical;
1881 pgoff_t index, end;
1882 long nr_to_write = wbc->nr_to_write;
1883 int i, tag, ret = 0;
1884
1885 memset(mpd, 0, sizeof(struct mpage_da_data));
1886 mpd->wbc = wbc;
1887 mpd->inode = inode;
1888 pagevec_init(&pvec, 0);
1889 index = wbc->range_start >> PAGE_CACHE_SHIFT;
1890 end = wbc->range_end >> PAGE_CACHE_SHIFT;
1891
1892 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
1893 tag = PAGECACHE_TAG_TOWRITE;
1894 else
1895 tag = PAGECACHE_TAG_DIRTY;
1896
1897 *done_index = index;
1898 while (index <= end) {
1899 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
1900 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
1901 if (nr_pages == 0)
1902 return 0;
1903
1904 for (i = 0; i < nr_pages; i++) {
1905 struct page *page = pvec.pages[i];
1906
1907 /*
1908 * At this point, the page may be truncated or
1909 * invalidated (changing page->mapping to NULL), or
1910 * even swizzled back from swapper_space to tmpfs file
1911 * mapping. However, page->index will not change
1912 * because we have a reference on the page.
1913 */
1914 if (page->index > end)
1915 goto out;
1916
1917 *done_index = page->index + 1;
1918
1919 /*
1920 * If we can't merge this page, and we have
1921 * accumulated an contiguous region, write it
1922 */
1923 if ((mpd->next_page != page->index) &&
1924 (mpd->next_page != mpd->first_page)) {
1925 mpage_da_map_and_submit(mpd);
1926 goto ret_extent_tail;
1927 }
1928
1929 lock_page(page);
1930
1931 /*
1932 * If the page is no longer dirty, or its
1933 * mapping no longer corresponds to inode we
1934 * are writing (which means it has been
1935 * truncated or invalidated), or the page is
1936 * already under writeback and we are not
1937 * doing a data integrity writeback, skip the page
1938 */
1939 if (!PageDirty(page) ||
1940 (PageWriteback(page) &&
1941 (wbc->sync_mode == WB_SYNC_NONE)) ||
1942 unlikely(page->mapping != mapping)) {
1943 unlock_page(page);
1944 continue;
1945 }
1946
1947 wait_on_page_writeback(page);
1948 BUG_ON(PageWriteback(page));
1949
1950 if (mpd->next_page != page->index)
1951 mpd->first_page = page->index;
1952 mpd->next_page = page->index + 1;
1953 logical = (sector_t) page->index <<
1954 (PAGE_CACHE_SHIFT - inode->i_blkbits);
1955
1956 if (!page_has_buffers(page)) {
1957 mpage_add_bh_to_extent(mpd, logical,
1958 PAGE_CACHE_SIZE,
1959 (1 << BH_Dirty) | (1 << BH_Uptodate));
1960 if (mpd->io_done)
1961 goto ret_extent_tail;
1962 } else {
1963 /*
1964 * Page with regular buffer heads,
1965 * just add all dirty ones
1966 */
1967 head = page_buffers(page);
1968 bh = head;
1969 do {
1970 BUG_ON(buffer_locked(bh));
1971 /*
1972 * We need to try to allocate
1973 * unmapped blocks in the same page.
1974 * Otherwise we won't make progress
1975 * with the page in ext4_writepage
1976 */
1977 if (ext4_bh_delay_or_unwritten(NULL, bh)) {
1978 mpage_add_bh_to_extent(mpd, logical,
1979 bh->b_size,
1980 bh->b_state);
1981 if (mpd->io_done)
1982 goto ret_extent_tail;
1983 } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
1984 /*
1985 * mapped dirty buffer. We need
1986 * to update the b_state
1987 * because we look at b_state
1988 * in mpage_da_map_blocks. We
1989 * don't update b_size because
1990 * if we find an unmapped
1991 * buffer_head later we need to
1992 * use the b_state flag of that
1993 * buffer_head.
1994 */
1995 if (mpd->b_size == 0)
1996 mpd->b_state = bh->b_state & BH_FLAGS;
1997 }
1998 logical++;
1999 } while ((bh = bh->b_this_page) != head);
2000 }
2001
2002 if (nr_to_write > 0) {
2003 nr_to_write--;
2004 if (nr_to_write == 0 &&
2005 wbc->sync_mode == WB_SYNC_NONE)
2006 /*
2007 * We stop writing back only if we are
2008 * not doing integrity sync. In case of
2009 * integrity sync we have to keep going
2010 * because someone may be concurrently
2011 * dirtying pages, and we might have
2012 * synced a lot of newly appeared dirty
2013 * pages, but have not synced all of the
2014 * old dirty pages.
2015 */
2016 goto out;
2017 }
2018 }
2019 pagevec_release(&pvec);
2020 cond_resched();
2021 }
2022 return 0;
2023ret_extent_tail:
2024 ret = MPAGE_DA_EXTENT_TAIL;
2025out:
2026 pagevec_release(&pvec);
2027 cond_resched();
2028 return ret;
2029}
2030
2031
2032static int ext4_da_writepages(struct address_space *mapping,
2033 struct writeback_control *wbc)
2034{
2035 pgoff_t index;
2036 int range_whole = 0;
2037 handle_t *handle = NULL;
2038 struct mpage_da_data mpd;
2039 struct inode *inode = mapping->host;
2040 int pages_written = 0;
2041 unsigned int max_pages;
2042 int range_cyclic, cycled = 1, io_done = 0;
2043 int needed_blocks, ret = 0;
2044 long desired_nr_to_write, nr_to_writebump = 0;
2045 loff_t range_start = wbc->range_start;
2046 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2047 pgoff_t done_index = 0;
2048 pgoff_t end;
2049
2050 trace_ext4_da_writepages(inode, wbc);
2051
2052 /*
2053 * No pages to write? This is mainly a kludge to avoid starting
2054 * a transaction for special inodes like journal inode on last iput()
2055 * because that could violate lock ordering on umount
2056 */
2057 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2058 return 0;
2059
2060 /*
2061 * If the filesystem has aborted, it is read-only, so return
2062 * right away instead of dumping stack traces later on that
2063 * will obscure the real source of the problem. We test
2064 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2065 * the latter could be true if the filesystem is mounted
2066 * read-only, and in that case, ext4_da_writepages should
2067 * *never* be called, so if that ever happens, we would want
2068 * the stack trace.
2069 */
2070 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2071 return -EROFS;
2072
2073 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2074 range_whole = 1;
2075
2076 range_cyclic = wbc->range_cyclic;
2077 if (wbc->range_cyclic) {
2078 index = mapping->writeback_index;
2079 if (index)
2080 cycled = 0;
2081 wbc->range_start = index << PAGE_CACHE_SHIFT;
2082 wbc->range_end = LLONG_MAX;
2083 wbc->range_cyclic = 0;
2084 end = -1;
2085 } else {
2086 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2087 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2088 }
2089
2090 /*
2091 * This works around two forms of stupidity. The first is in
2092 * the writeback code, which caps the maximum number of pages
2093 * written to be 1024 pages. This is wrong on multiple
2094 * levels; different architectues have a different page size,
2095 * which changes the maximum amount of data which gets
2096 * written. Secondly, 4 megabytes is way too small. XFS
2097 * forces this value to be 16 megabytes by multiplying
2098 * nr_to_write parameter by four, and then relies on its
2099 * allocator to allocate larger extents to make them
2100 * contiguous. Unfortunately this brings us to the second
2101 * stupidity, which is that ext4's mballoc code only allocates
2102 * at most 2048 blocks. So we force contiguous writes up to
2103 * the number of dirty blocks in the inode, or
2104 * sbi->max_writeback_mb_bump whichever is smaller.
2105 */
2106 max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2107 if (!range_cyclic && range_whole) {
2108 if (wbc->nr_to_write == LONG_MAX)
2109 desired_nr_to_write = wbc->nr_to_write;
2110 else
2111 desired_nr_to_write = wbc->nr_to_write * 8;
2112 } else
2113 desired_nr_to_write = ext4_num_dirty_pages(inode, index,
2114 max_pages);
2115 if (desired_nr_to_write > max_pages)
2116 desired_nr_to_write = max_pages;
2117
2118 if (wbc->nr_to_write < desired_nr_to_write) {
2119 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
2120 wbc->nr_to_write = desired_nr_to_write;
2121 }
2122
2123retry:
2124 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2125 tag_pages_for_writeback(mapping, index, end);
2126
2127 while (!ret && wbc->nr_to_write > 0) {
2128
2129 /*
2130 * we insert one extent at a time. So we need
2131 * credit needed for single extent allocation.
2132 * journalled mode is currently not supported
2133 * by delalloc
2134 */
2135 BUG_ON(ext4_should_journal_data(inode));
2136 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2137
2138 /* start a new transaction*/
2139 handle = ext4_journal_start(inode, needed_blocks);
2140 if (IS_ERR(handle)) {
2141 ret = PTR_ERR(handle);
2142 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2143 "%ld pages, ino %lu; err %d", __func__,
2144 wbc->nr_to_write, inode->i_ino, ret);
2145 goto out_writepages;
2146 }
2147
2148 /*
2149 * Now call write_cache_pages_da() to find the next
2150 * contiguous region of logical blocks that need
2151 * blocks to be allocated by ext4 and submit them.
2152 */
2153 ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index);
2154 /*
2155 * If we have a contiguous extent of pages and we
2156 * haven't done the I/O yet, map the blocks and submit
2157 * them for I/O.
2158 */
2159 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2160 mpage_da_map_and_submit(&mpd);
2161 ret = MPAGE_DA_EXTENT_TAIL;
2162 }
2163 trace_ext4_da_write_pages(inode, &mpd);
2164 wbc->nr_to_write -= mpd.pages_written;
2165
2166 ext4_journal_stop(handle);
2167
2168 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2169 /* commit the transaction which would
2170 * free blocks released in the transaction
2171 * and try again
2172 */
2173 jbd2_journal_force_commit_nested(sbi->s_journal);
2174 ret = 0;
2175 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2176 /*
2177 * got one extent now try with
2178 * rest of the pages
2179 */
2180 pages_written += mpd.pages_written;
2181 ret = 0;
2182 io_done = 1;
2183 } else if (wbc->nr_to_write)
2184 /*
2185 * There is no more writeout needed
2186 * or we requested for a noblocking writeout
2187 * and we found the device congested
2188 */
2189 break;
2190 }
2191 if (!io_done && !cycled) {
2192 cycled = 1;
2193 index = 0;
2194 wbc->range_start = index << PAGE_CACHE_SHIFT;
2195 wbc->range_end = mapping->writeback_index - 1;
2196 goto retry;
2197 }
2198
2199 /* Update index */
2200 wbc->range_cyclic = range_cyclic;
2201 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2202 /*
2203 * set the writeback_index so that range_cyclic
2204 * mode will write it back later
2205 */
2206 mapping->writeback_index = done_index;
2207
2208out_writepages:
2209 wbc->nr_to_write -= nr_to_writebump;
2210 wbc->range_start = range_start;
2211 trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
2212 return ret;
2213}
2214
2215#define FALL_BACK_TO_NONDELALLOC 1
2216static int ext4_nonda_switch(struct super_block *sb)
2217{
2218 s64 free_blocks, dirty_blocks;
2219 struct ext4_sb_info *sbi = EXT4_SB(sb);
2220
2221 /*
2222 * switch to non delalloc mode if we are running low
2223 * on free block. The free block accounting via percpu
2224 * counters can get slightly wrong with percpu_counter_batch getting
2225 * accumulated on each CPU without updating global counters
2226 * Delalloc need an accurate free block accounting. So switch
2227 * to non delalloc when we are near to error range.
2228 */
2229 free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
2230 dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
2231 if (2 * free_blocks < 3 * dirty_blocks ||
2232 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
2233 /*
2234 * free block count is less than 150% of dirty blocks
2235 * or free blocks is less than watermark
2236 */
2237 return 1;
2238 }
2239 /*
2240 * Even if we don't switch but are nearing capacity,
2241 * start pushing delalloc when 1/2 of free blocks are dirty.
2242 */
2243 if (free_blocks < 2 * dirty_blocks)
2244 writeback_inodes_sb_if_idle(sb);
2245
2246 return 0;
2247}
2248
2249static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2250 loff_t pos, unsigned len, unsigned flags,
2251 struct page **pagep, void **fsdata)
2252{
2253 int ret, retries = 0;
2254 struct page *page;
2255 pgoff_t index;
2256 struct inode *inode = mapping->host;
2257 handle_t *handle;
2258
2259 index = pos >> PAGE_CACHE_SHIFT;
2260
2261 if (ext4_nonda_switch(inode->i_sb)) {
2262 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2263 return ext4_write_begin(file, mapping, pos,
2264 len, flags, pagep, fsdata);
2265 }
2266 *fsdata = (void *)0;
2267 trace_ext4_da_write_begin(inode, pos, len, flags);
2268retry:
2269 /*
2270 * With delayed allocation, we don't log the i_disksize update
2271 * if there is delayed block allocation. But we still need
2272 * to journalling the i_disksize update if writes to the end
2273 * of file which has an already mapped buffer.
2274 */
2275 handle = ext4_journal_start(inode, 1);
2276 if (IS_ERR(handle)) {
2277 ret = PTR_ERR(handle);
2278 goto out;
2279 }
2280 /* We cannot recurse into the filesystem as the transaction is already
2281 * started */
2282 flags |= AOP_FLAG_NOFS;
2283
2284 page = grab_cache_page_write_begin(mapping, index, flags);
2285 if (!page) {
2286 ext4_journal_stop(handle);
2287 ret = -ENOMEM;
2288 goto out;
2289 }
2290 *pagep = page;
2291
2292 ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2293 if (ret < 0) {
2294 unlock_page(page);
2295 ext4_journal_stop(handle);
2296 page_cache_release(page);
2297 /*
2298 * block_write_begin may have instantiated a few blocks
2299 * outside i_size. Trim these off again. Don't need
2300 * i_size_read because we hold i_mutex.
2301 */
2302 if (pos + len > inode->i_size)
2303 ext4_truncate_failed_write(inode);
2304 }
2305
2306 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2307 goto retry;
2308out:
2309 return ret;
2310}
2311
2312/*
2313 * Check if we should update i_disksize
2314 * when write to the end of file but not require block allocation
2315 */
2316static int ext4_da_should_update_i_disksize(struct page *page,
2317 unsigned long offset)
2318{
2319 struct buffer_head *bh;
2320 struct inode *inode = page->mapping->host;
2321 unsigned int idx;
2322 int i;
2323
2324 bh = page_buffers(page);
2325 idx = offset >> inode->i_blkbits;
2326
2327 for (i = 0; i < idx; i++)
2328 bh = bh->b_this_page;
2329
2330 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2331 return 0;
2332 return 1;
2333}
2334
2335static int ext4_da_write_end(struct file *file,
2336 struct address_space *mapping,
2337 loff_t pos, unsigned len, unsigned copied,
2338 struct page *page, void *fsdata)
2339{
2340 struct inode *inode = mapping->host;
2341 int ret = 0, ret2;
2342 handle_t *handle = ext4_journal_current_handle();
2343 loff_t new_i_size;
2344 unsigned long start, end;
2345 int write_mode = (int)(unsigned long)fsdata;
2346
2347 if (write_mode == FALL_BACK_TO_NONDELALLOC) {
2348 if (ext4_should_order_data(inode)) {
2349 return ext4_ordered_write_end(file, mapping, pos,
2350 len, copied, page, fsdata);
2351 } else if (ext4_should_writeback_data(inode)) {
2352 return ext4_writeback_write_end(file, mapping, pos,
2353 len, copied, page, fsdata);
2354 } else {
2355 BUG();
2356 }
2357 }
2358
2359 trace_ext4_da_write_end(inode, pos, len, copied);
2360 start = pos & (PAGE_CACHE_SIZE - 1);
2361 end = start + copied - 1;
2362
2363 /*
2364 * generic_write_end() will run mark_inode_dirty() if i_size
2365 * changes. So let's piggyback the i_disksize mark_inode_dirty
2366 * into that.
2367 */
2368
2369 new_i_size = pos + copied;
2370 if (new_i_size > EXT4_I(inode)->i_disksize) {
2371 if (ext4_da_should_update_i_disksize(page, end)) {
2372 down_write(&EXT4_I(inode)->i_data_sem);
2373 if (new_i_size > EXT4_I(inode)->i_disksize) {
2374 /*
2375 * Updating i_disksize when extending file
2376 * without needing block allocation
2377 */
2378 if (ext4_should_order_data(inode))
2379 ret = ext4_jbd2_file_inode(handle,
2380 inode);
2381
2382 EXT4_I(inode)->i_disksize = new_i_size;
2383 }
2384 up_write(&EXT4_I(inode)->i_data_sem);
2385 /* We need to mark inode dirty even if
2386 * new_i_size is less that inode->i_size
2387 * bu greater than i_disksize.(hint delalloc)
2388 */
2389 ext4_mark_inode_dirty(handle, inode);
2390 }
2391 }
2392 ret2 = generic_write_end(file, mapping, pos, len, copied,
2393 page, fsdata);
2394 copied = ret2;
2395 if (ret2 < 0)
2396 ret = ret2;
2397 ret2 = ext4_journal_stop(handle);
2398 if (!ret)
2399 ret = ret2;
2400
2401 return ret ? ret : copied;
2402}
2403
2404static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
2405{
2406 /*
2407 * Drop reserved blocks
2408 */
2409 BUG_ON(!PageLocked(page));
2410 if (!page_has_buffers(page))
2411 goto out;
2412
2413 ext4_da_page_release_reservation(page, offset);
2414
2415out:
2416 ext4_invalidatepage(page, offset);
2417
2418 return;
2419}
2420
2421/*
2422 * Force all delayed allocation blocks to be allocated for a given inode.
2423 */
2424int ext4_alloc_da_blocks(struct inode *inode)
2425{
2426 trace_ext4_alloc_da_blocks(inode);
2427
2428 if (!EXT4_I(inode)->i_reserved_data_blocks &&
2429 !EXT4_I(inode)->i_reserved_meta_blocks)
2430 return 0;
2431
2432 /*
2433 * We do something simple for now. The filemap_flush() will
2434 * also start triggering a write of the data blocks, which is
2435 * not strictly speaking necessary (and for users of
2436 * laptop_mode, not even desirable). However, to do otherwise
2437 * would require replicating code paths in:
2438 *
2439 * ext4_da_writepages() ->
2440 * write_cache_pages() ---> (via passed in callback function)
2441 * __mpage_da_writepage() -->
2442 * mpage_add_bh_to_extent()
2443 * mpage_da_map_blocks()
2444 *
2445 * The problem is that write_cache_pages(), located in
2446 * mm/page-writeback.c, marks pages clean in preparation for
2447 * doing I/O, which is not desirable if we're not planning on
2448 * doing I/O at all.
2449 *
2450 * We could call write_cache_pages(), and then redirty all of
2451 * the pages by calling redirty_page_for_writepage() but that
2452 * would be ugly in the extreme. So instead we would need to
2453 * replicate parts of the code in the above functions,
2454 * simplifying them because we wouldn't actually intend to
2455 * write out the pages, but rather only collect contiguous
2456 * logical block extents, call the multi-block allocator, and
2457 * then update the buffer heads with the block allocations.
2458 *
2459 * For now, though, we'll cheat by calling filemap_flush(),
2460 * which will map the blocks, and start the I/O, but not
2461 * actually wait for the I/O to complete.
2462 */
2463 return filemap_flush(inode->i_mapping);
2464}
2465
2466/*
2467 * bmap() is special. It gets used by applications such as lilo and by
2468 * the swapper to find the on-disk block of a specific piece of data.
2469 *
2470 * Naturally, this is dangerous if the block concerned is still in the
2471 * journal. If somebody makes a swapfile on an ext4 data-journaling
2472 * filesystem and enables swap, then they may get a nasty shock when the
2473 * data getting swapped to that swapfile suddenly gets overwritten by
2474 * the original zero's written out previously to the journal and
2475 * awaiting writeback in the kernel's buffer cache.
2476 *
2477 * So, if we see any bmap calls here on a modified, data-journaled file,
2478 * take extra steps to flush any blocks which might be in the cache.
2479 */
2480static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2481{
2482 struct inode *inode = mapping->host;
2483 journal_t *journal;
2484 int err;
2485
2486 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
2487 test_opt(inode->i_sb, DELALLOC)) {
2488 /*
2489 * With delalloc we want to sync the file
2490 * so that we can make sure we allocate
2491 * blocks for file
2492 */
2493 filemap_write_and_wait(mapping);
2494 }
2495
2496 if (EXT4_JOURNAL(inode) &&
2497 ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
2498 /*
2499 * This is a REALLY heavyweight approach, but the use of
2500 * bmap on dirty files is expected to be extremely rare:
2501 * only if we run lilo or swapon on a freshly made file
2502 * do we expect this to happen.
2503 *
2504 * (bmap requires CAP_SYS_RAWIO so this does not
2505 * represent an unprivileged user DOS attack --- we'd be
2506 * in trouble if mortal users could trigger this path at
2507 * will.)
2508 *
2509 * NB. EXT4_STATE_JDATA is not set on files other than
2510 * regular files. If somebody wants to bmap a directory
2511 * or symlink and gets confused because the buffer
2512 * hasn't yet been flushed to disk, they deserve
2513 * everything they get.
2514 */
2515
2516 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
2517 journal = EXT4_JOURNAL(inode);
2518 jbd2_journal_lock_updates(journal);
2519 err = jbd2_journal_flush(journal);
2520 jbd2_journal_unlock_updates(journal);
2521
2522 if (err)
2523 return 0;
2524 }
2525
2526 return generic_block_bmap(mapping, block, ext4_get_block);
2527}
2528
2529static int ext4_readpage(struct file *file, struct page *page)
2530{
2531 trace_ext4_readpage(page);
2532 return mpage_readpage(page, ext4_get_block);
2533}
2534
2535static int
2536ext4_readpages(struct file *file, struct address_space *mapping,
2537 struct list_head *pages, unsigned nr_pages)
2538{
2539 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
2540}
2541
2542static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
2543{
2544 struct buffer_head *head, *bh;
2545 unsigned int curr_off = 0;
2546
2547 if (!page_has_buffers(page))
2548 return;
2549 head = bh = page_buffers(page);
2550 do {
2551 if (offset <= curr_off && test_clear_buffer_uninit(bh)
2552 && bh->b_private) {
2553 ext4_free_io_end(bh->b_private);
2554 bh->b_private = NULL;
2555 bh->b_end_io = NULL;
2556 }
2557 curr_off = curr_off + bh->b_size;
2558 bh = bh->b_this_page;
2559 } while (bh != head);
2560}
2561
2562static void ext4_invalidatepage(struct page *page, unsigned long offset)
2563{
2564 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2565
2566 trace_ext4_invalidatepage(page, offset);
2567
2568 /*
2569 * free any io_end structure allocated for buffers to be discarded
2570 */
2571 if (ext4_should_dioread_nolock(page->mapping->host))
2572 ext4_invalidatepage_free_endio(page, offset);
2573 /*
2574 * If it's a full truncate we just forget about the pending dirtying
2575 */
2576 if (offset == 0)
2577 ClearPageChecked(page);
2578
2579 if (journal)
2580 jbd2_journal_invalidatepage(journal, page, offset);
2581 else
2582 block_invalidatepage(page, offset);
2583}
2584
2585static int ext4_releasepage(struct page *page, gfp_t wait)
2586{
2587 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2588
2589 trace_ext4_releasepage(page);
2590
2591 WARN_ON(PageChecked(page));
2592 if (!page_has_buffers(page))
2593 return 0;
2594 if (journal)
2595 return jbd2_journal_try_to_free_buffers(journal, page, wait);
2596 else
2597 return try_to_free_buffers(page);
2598}
2599
2600/*
2601 * ext4_get_block used when preparing for a DIO write or buffer write.
2602 * We allocate an uinitialized extent if blocks haven't been allocated.
2603 * The extent will be converted to initialized after the IO is complete.
2604 */
2605static int ext4_get_block_write(struct inode *inode, sector_t iblock,
2606 struct buffer_head *bh_result, int create)
2607{
2608 ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
2609 inode->i_ino, create);
2610 return _ext4_get_block(inode, iblock, bh_result,
2611 EXT4_GET_BLOCKS_IO_CREATE_EXT);
2612}
2613
2614static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
2615 ssize_t size, void *private, int ret,
2616 bool is_async)
2617{
2618 struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
2619 ext4_io_end_t *io_end = iocb->private;
2620 struct workqueue_struct *wq;
2621 unsigned long flags;
2622 struct ext4_inode_info *ei;
2623
2624 /* if not async direct IO or dio with 0 bytes write, just return */
2625 if (!io_end || !size)
2626 goto out;
2627
2628 ext_debug("ext4_end_io_dio(): io_end 0x%p"
2629 "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
2630 iocb->private, io_end->inode->i_ino, iocb, offset,
2631 size);
2632
2633 /* if not aio dio with unwritten extents, just free io and return */
2634 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
2635 ext4_free_io_end(io_end);
2636 iocb->private = NULL;
2637out:
2638 if (is_async)
2639 aio_complete(iocb, ret, 0);
2640 inode_dio_done(inode);
2641 return;
2642 }
2643
2644 io_end->offset = offset;
2645 io_end->size = size;
2646 if (is_async) {
2647 io_end->iocb = iocb;
2648 io_end->result = ret;
2649 }
2650 wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
2651
2652 /* Add the io_end to per-inode completed aio dio list*/
2653 ei = EXT4_I(io_end->inode);
2654 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
2655 list_add_tail(&io_end->list, &ei->i_completed_io_list);
2656 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
2657
2658 /* queue the work to convert unwritten extents to written */
2659 queue_work(wq, &io_end->work);
2660 iocb->private = NULL;
2661
2662 /* XXX: probably should move into the real I/O completion handler */
2663 inode_dio_done(inode);
2664}
2665
2666static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
2667{
2668 ext4_io_end_t *io_end = bh->b_private;
2669 struct workqueue_struct *wq;
2670 struct inode *inode;
2671 unsigned long flags;
2672
2673 if (!test_clear_buffer_uninit(bh) || !io_end)
2674 goto out;
2675
2676 if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
2677 printk("sb umounted, discard end_io request for inode %lu\n",
2678 io_end->inode->i_ino);
2679 ext4_free_io_end(io_end);
2680 goto out;
2681 }
2682
2683 /*
2684 * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now,
2685 * but being more careful is always safe for the future change.
2686 */
2687 inode = io_end->inode;
2688 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
2689 io_end->flag |= EXT4_IO_END_UNWRITTEN;
2690 atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
2691 }
2692
2693 /* Add the io_end to per-inode completed io list*/
2694 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
2695 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
2696 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
2697
2698 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
2699 /* queue the work to convert unwritten extents to written */
2700 queue_work(wq, &io_end->work);
2701out:
2702 bh->b_private = NULL;
2703 bh->b_end_io = NULL;
2704 clear_buffer_uninit(bh);
2705 end_buffer_async_write(bh, uptodate);
2706}
2707
2708static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
2709{
2710 ext4_io_end_t *io_end;
2711 struct page *page = bh->b_page;
2712 loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
2713 size_t size = bh->b_size;
2714
2715retry:
2716 io_end = ext4_init_io_end(inode, GFP_ATOMIC);
2717 if (!io_end) {
2718 pr_warn_ratelimited("%s: allocation fail\n", __func__);
2719 schedule();
2720 goto retry;
2721 }
2722 io_end->offset = offset;
2723 io_end->size = size;
2724 /*
2725 * We need to hold a reference to the page to make sure it
2726 * doesn't get evicted before ext4_end_io_work() has a chance
2727 * to convert the extent from written to unwritten.
2728 */
2729 io_end->page = page;
2730 get_page(io_end->page);
2731
2732 bh->b_private = io_end;
2733 bh->b_end_io = ext4_end_io_buffer_write;
2734 return 0;
2735}
2736
2737/*
2738 * For ext4 extent files, ext4 will do direct-io write to holes,
2739 * preallocated extents, and those write extend the file, no need to
2740 * fall back to buffered IO.
2741 *
2742 * For holes, we fallocate those blocks, mark them as uninitialized
2743 * If those blocks were preallocated, we mark sure they are splited, but
2744 * still keep the range to write as uninitialized.
2745 *
2746 * The unwrritten extents will be converted to written when DIO is completed.
2747 * For async direct IO, since the IO may still pending when return, we
2748 * set up an end_io call back function, which will do the conversion
2749 * when async direct IO completed.
2750 *
2751 * If the O_DIRECT write will extend the file then add this inode to the
2752 * orphan list. So recovery will truncate it back to the original size
2753 * if the machine crashes during the write.
2754 *
2755 */
2756static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
2757 const struct iovec *iov, loff_t offset,
2758 unsigned long nr_segs)
2759{
2760 struct file *file = iocb->ki_filp;
2761 struct inode *inode = file->f_mapping->host;
2762 ssize_t ret;
2763 size_t count = iov_length(iov, nr_segs);
2764
2765 loff_t final_size = offset + count;
2766 if (rw == WRITE && final_size <= inode->i_size) {
2767 /*
2768 * We could direct write to holes and fallocate.
2769 *
2770 * Allocated blocks to fill the hole are marked as uninitialized
2771 * to prevent parallel buffered read to expose the stale data
2772 * before DIO complete the data IO.
2773 *
2774 * As to previously fallocated extents, ext4 get_block
2775 * will just simply mark the buffer mapped but still
2776 * keep the extents uninitialized.
2777 *
2778 * for non AIO case, we will convert those unwritten extents
2779 * to written after return back from blockdev_direct_IO.
2780 *
2781 * for async DIO, the conversion needs to be defered when
2782 * the IO is completed. The ext4 end_io callback function
2783 * will be called to take care of the conversion work.
2784 * Here for async case, we allocate an io_end structure to
2785 * hook to the iocb.
2786 */
2787 iocb->private = NULL;
2788 EXT4_I(inode)->cur_aio_dio = NULL;
2789 if (!is_sync_kiocb(iocb)) {
2790 iocb->private = ext4_init_io_end(inode, GFP_NOFS);
2791 if (!iocb->private)
2792 return -ENOMEM;
2793 /*
2794 * we save the io structure for current async
2795 * direct IO, so that later ext4_map_blocks()
2796 * could flag the io structure whether there
2797 * is a unwritten extents needs to be converted
2798 * when IO is completed.
2799 */
2800 EXT4_I(inode)->cur_aio_dio = iocb->private;
2801 }
2802
2803 ret = __blockdev_direct_IO(rw, iocb, inode,
2804 inode->i_sb->s_bdev, iov,
2805 offset, nr_segs,
2806 ext4_get_block_write,
2807 ext4_end_io_dio,
2808 NULL,
2809 DIO_LOCKING | DIO_SKIP_HOLES);
2810 if (iocb->private)
2811 EXT4_I(inode)->cur_aio_dio = NULL;
2812 /*
2813 * The io_end structure takes a reference to the inode,
2814 * that structure needs to be destroyed and the
2815 * reference to the inode need to be dropped, when IO is
2816 * complete, even with 0 byte write, or failed.
2817 *
2818 * In the successful AIO DIO case, the io_end structure will be
2819 * desctroyed and the reference to the inode will be dropped
2820 * after the end_io call back function is called.
2821 *
2822 * In the case there is 0 byte write, or error case, since
2823 * VFS direct IO won't invoke the end_io call back function,
2824 * we need to free the end_io structure here.
2825 */
2826 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
2827 ext4_free_io_end(iocb->private);
2828 iocb->private = NULL;
2829 } else if (ret > 0 && ext4_test_inode_state(inode,
2830 EXT4_STATE_DIO_UNWRITTEN)) {
2831 int err;
2832 /*
2833 * for non AIO case, since the IO is already
2834 * completed, we could do the conversion right here
2835 */
2836 err = ext4_convert_unwritten_extents(inode,
2837 offset, ret);
2838 if (err < 0)
2839 ret = err;
2840 ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
2841 }
2842 return ret;
2843 }
2844
2845 /* for write the the end of file case, we fall back to old way */
2846 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
2847}
2848
2849static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
2850 const struct iovec *iov, loff_t offset,
2851 unsigned long nr_segs)
2852{
2853 struct file *file = iocb->ki_filp;
2854 struct inode *inode = file->f_mapping->host;
2855 ssize_t ret;
2856
2857 trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
2858 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
2859 ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
2860 else
2861 ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
2862 trace_ext4_direct_IO_exit(inode, offset,
2863 iov_length(iov, nr_segs), rw, ret);
2864 return ret;
2865}
2866
2867/*
2868 * Pages can be marked dirty completely asynchronously from ext4's journalling
2869 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
2870 * much here because ->set_page_dirty is called under VFS locks. The page is
2871 * not necessarily locked.
2872 *
2873 * We cannot just dirty the page and leave attached buffers clean, because the
2874 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
2875 * or jbddirty because all the journalling code will explode.
2876 *
2877 * So what we do is to mark the page "pending dirty" and next time writepage
2878 * is called, propagate that into the buffers appropriately.
2879 */
2880static int ext4_journalled_set_page_dirty(struct page *page)
2881{
2882 SetPageChecked(page);
2883 return __set_page_dirty_nobuffers(page);
2884}
2885
2886static const struct address_space_operations ext4_ordered_aops = {
2887 .readpage = ext4_readpage,
2888 .readpages = ext4_readpages,
2889 .writepage = ext4_writepage,
2890 .write_begin = ext4_write_begin,
2891 .write_end = ext4_ordered_write_end,
2892 .bmap = ext4_bmap,
2893 .invalidatepage = ext4_invalidatepage,
2894 .releasepage = ext4_releasepage,
2895 .direct_IO = ext4_direct_IO,
2896 .migratepage = buffer_migrate_page,
2897 .is_partially_uptodate = block_is_partially_uptodate,
2898 .error_remove_page = generic_error_remove_page,
2899};
2900
2901static const struct address_space_operations ext4_writeback_aops = {
2902 .readpage = ext4_readpage,
2903 .readpages = ext4_readpages,
2904 .writepage = ext4_writepage,
2905 .write_begin = ext4_write_begin,
2906 .write_end = ext4_writeback_write_end,
2907 .bmap = ext4_bmap,
2908 .invalidatepage = ext4_invalidatepage,
2909 .releasepage = ext4_releasepage,
2910 .direct_IO = ext4_direct_IO,
2911 .migratepage = buffer_migrate_page,
2912 .is_partially_uptodate = block_is_partially_uptodate,
2913 .error_remove_page = generic_error_remove_page,
2914};
2915
2916static const struct address_space_operations ext4_journalled_aops = {
2917 .readpage = ext4_readpage,
2918 .readpages = ext4_readpages,
2919 .writepage = ext4_writepage,
2920 .write_begin = ext4_write_begin,
2921 .write_end = ext4_journalled_write_end,
2922 .set_page_dirty = ext4_journalled_set_page_dirty,
2923 .bmap = ext4_bmap,
2924 .invalidatepage = ext4_invalidatepage,
2925 .releasepage = ext4_releasepage,
2926 .is_partially_uptodate = block_is_partially_uptodate,
2927 .error_remove_page = generic_error_remove_page,
2928};
2929
2930static const struct address_space_operations ext4_da_aops = {
2931 .readpage = ext4_readpage,
2932 .readpages = ext4_readpages,
2933 .writepage = ext4_writepage,
2934 .writepages = ext4_da_writepages,
2935 .write_begin = ext4_da_write_begin,
2936 .write_end = ext4_da_write_end,
2937 .bmap = ext4_bmap,
2938 .invalidatepage = ext4_da_invalidatepage,
2939 .releasepage = ext4_releasepage,
2940 .direct_IO = ext4_direct_IO,
2941 .migratepage = buffer_migrate_page,
2942 .is_partially_uptodate = block_is_partially_uptodate,
2943 .error_remove_page = generic_error_remove_page,
2944};
2945
2946void ext4_set_aops(struct inode *inode)
2947{
2948 if (ext4_should_order_data(inode) &&
2949 test_opt(inode->i_sb, DELALLOC))
2950 inode->i_mapping->a_ops = &ext4_da_aops;
2951 else if (ext4_should_order_data(inode))
2952 inode->i_mapping->a_ops = &ext4_ordered_aops;
2953 else if (ext4_should_writeback_data(inode) &&
2954 test_opt(inode->i_sb, DELALLOC))
2955 inode->i_mapping->a_ops = &ext4_da_aops;
2956 else if (ext4_should_writeback_data(inode))
2957 inode->i_mapping->a_ops = &ext4_writeback_aops;
2958 else
2959 inode->i_mapping->a_ops = &ext4_journalled_aops;
2960}
2961
2962/*
2963 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
2964 * up to the end of the block which corresponds to `from'.
2965 * This required during truncate. We need to physically zero the tail end
2966 * of that block so it doesn't yield old data if the file is later grown.
2967 */
2968int ext4_block_truncate_page(handle_t *handle,
2969 struct address_space *mapping, loff_t from)
2970{
2971 unsigned offset = from & (PAGE_CACHE_SIZE-1);
2972 unsigned length;
2973 unsigned blocksize;
2974 struct inode *inode = mapping->host;
2975
2976 blocksize = inode->i_sb->s_blocksize;
2977 length = blocksize - (offset & (blocksize - 1));
2978
2979 return ext4_block_zero_page_range(handle, mapping, from, length);
2980}
2981
2982/*
2983 * ext4_block_zero_page_range() zeros out a mapping of length 'length'
2984 * starting from file offset 'from'. The range to be zero'd must
2985 * be contained with in one block. If the specified range exceeds
2986 * the end of the block it will be shortened to end of the block
2987 * that cooresponds to 'from'
2988 */
2989int ext4_block_zero_page_range(handle_t *handle,
2990 struct address_space *mapping, loff_t from, loff_t length)
2991{
2992 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
2993 unsigned offset = from & (PAGE_CACHE_SIZE-1);
2994 unsigned blocksize, max, pos;
2995 ext4_lblk_t iblock;
2996 struct inode *inode = mapping->host;
2997 struct buffer_head *bh;
2998 struct page *page;
2999 int err = 0;
3000
3001 page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3002 mapping_gfp_mask(mapping) & ~__GFP_FS);
3003 if (!page)
3004 return -EINVAL;
3005
3006 blocksize = inode->i_sb->s_blocksize;
3007 max = blocksize - (offset & (blocksize - 1));
3008
3009 /*
3010 * correct length if it does not fall between
3011 * 'from' and the end of the block
3012 */
3013 if (length > max || length < 0)
3014 length = max;
3015
3016 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3017
3018 if (!page_has_buffers(page))
3019 create_empty_buffers(page, blocksize, 0);
3020
3021 /* Find the buffer that contains "offset" */
3022 bh = page_buffers(page);
3023 pos = blocksize;
3024 while (offset >= pos) {
3025 bh = bh->b_this_page;
3026 iblock++;
3027 pos += blocksize;
3028 }
3029
3030 err = 0;
3031 if (buffer_freed(bh)) {
3032 BUFFER_TRACE(bh, "freed: skip");
3033 goto unlock;
3034 }
3035
3036 if (!buffer_mapped(bh)) {
3037 BUFFER_TRACE(bh, "unmapped");
3038 ext4_get_block(inode, iblock, bh, 0);
3039 /* unmapped? It's a hole - nothing to do */
3040 if (!buffer_mapped(bh)) {
3041 BUFFER_TRACE(bh, "still unmapped");
3042 goto unlock;
3043 }
3044 }
3045
3046 /* Ok, it's mapped. Make sure it's up-to-date */
3047 if (PageUptodate(page))
3048 set_buffer_uptodate(bh);
3049
3050 if (!buffer_uptodate(bh)) {
3051 err = -EIO;
3052 ll_rw_block(READ, 1, &bh);
3053 wait_on_buffer(bh);
3054 /* Uhhuh. Read error. Complain and punt. */
3055 if (!buffer_uptodate(bh))
3056 goto unlock;
3057 }
3058
3059 if (ext4_should_journal_data(inode)) {
3060 BUFFER_TRACE(bh, "get write access");
3061 err = ext4_journal_get_write_access(handle, bh);
3062 if (err)
3063 goto unlock;
3064 }
3065
3066 zero_user(page, offset, length);
3067
3068 BUFFER_TRACE(bh, "zeroed end of block");
3069
3070 err = 0;
3071 if (ext4_should_journal_data(inode)) {
3072 err = ext4_handle_dirty_metadata(handle, inode, bh);
3073 } else {
3074 if (ext4_should_order_data(inode) && EXT4_I(inode)->jinode)
3075 err = ext4_jbd2_file_inode(handle, inode);
3076 mark_buffer_dirty(bh);
3077 }
3078
3079unlock:
3080 unlock_page(page);
3081 page_cache_release(page);
3082 return err;
3083}
3084
3085int ext4_can_truncate(struct inode *inode)
3086{
3087 if (S_ISREG(inode->i_mode))
3088 return 1;
3089 if (S_ISDIR(inode->i_mode))
3090 return 1;
3091 if (S_ISLNK(inode->i_mode))
3092 return !ext4_inode_is_fast_symlink(inode);
3093 return 0;
3094}
3095
3096/*
3097 * ext4_punch_hole: punches a hole in a file by releaseing the blocks
3098 * associated with the given offset and length
3099 *
3100 * @inode: File inode
3101 * @offset: The offset where the hole will begin
3102 * @len: The length of the hole
3103 *
3104 * Returns: 0 on sucess or negative on failure
3105 */
3106
3107int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
3108{
3109 struct inode *inode = file->f_path.dentry->d_inode;
3110 if (!S_ISREG(inode->i_mode))
3111 return -ENOTSUPP;
3112
3113 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
3114 /* TODO: Add support for non extent hole punching */
3115 return -ENOTSUPP;
3116 }
3117
3118 return ext4_ext_punch_hole(file, offset, length);
3119}
3120
3121/*
3122 * ext4_truncate()
3123 *
3124 * We block out ext4_get_block() block instantiations across the entire
3125 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3126 * simultaneously on behalf of the same inode.
3127 *
3128 * As we work through the truncate and commmit bits of it to the journal there
3129 * is one core, guiding principle: the file's tree must always be consistent on
3130 * disk. We must be able to restart the truncate after a crash.
3131 *
3132 * The file's tree may be transiently inconsistent in memory (although it
3133 * probably isn't), but whenever we close off and commit a journal transaction,
3134 * the contents of (the filesystem + the journal) must be consistent and
3135 * restartable. It's pretty simple, really: bottom up, right to left (although
3136 * left-to-right works OK too).
3137 *
3138 * Note that at recovery time, journal replay occurs *before* the restart of
3139 * truncate against the orphan inode list.
3140 *
3141 * The committed inode has the new, desired i_size (which is the same as
3142 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
3143 * that this inode's truncate did not complete and it will again call
3144 * ext4_truncate() to have another go. So there will be instantiated blocks
3145 * to the right of the truncation point in a crashed ext4 filesystem. But
3146 * that's fine - as long as they are linked from the inode, the post-crash
3147 * ext4_truncate() run will find them and release them.
3148 */
3149void ext4_truncate(struct inode *inode)
3150{
3151 trace_ext4_truncate_enter(inode);
3152
3153 if (!ext4_can_truncate(inode))
3154 return;
3155
3156 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3157
3158 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
3159 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
3160
3161 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3162 ext4_ext_truncate(inode);
3163 else
3164 ext4_ind_truncate(inode);
3165
3166 trace_ext4_truncate_exit(inode);
3167}
3168
3169/*
3170 * ext4_get_inode_loc returns with an extra refcount against the inode's
3171 * underlying buffer_head on success. If 'in_mem' is true, we have all
3172 * data in memory that is needed to recreate the on-disk version of this
3173 * inode.
3174 */
3175static int __ext4_get_inode_loc(struct inode *inode,
3176 struct ext4_iloc *iloc, int in_mem)
3177{
3178 struct ext4_group_desc *gdp;
3179 struct buffer_head *bh;
3180 struct super_block *sb = inode->i_sb;
3181 ext4_fsblk_t block;
3182 int inodes_per_block, inode_offset;
3183
3184 iloc->bh = NULL;
3185 if (!ext4_valid_inum(sb, inode->i_ino))
3186 return -EIO;
3187
3188 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
3189 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
3190 if (!gdp)
3191 return -EIO;
3192
3193 /*
3194 * Figure out the offset within the block group inode table
3195 */
3196 inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
3197 inode_offset = ((inode->i_ino - 1) %
3198 EXT4_INODES_PER_GROUP(sb));
3199 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
3200 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
3201
3202 bh = sb_getblk(sb, block);
3203 if (!bh) {
3204 EXT4_ERROR_INODE_BLOCK(inode, block,
3205 "unable to read itable block");
3206 return -EIO;
3207 }
3208 if (!buffer_uptodate(bh)) {
3209 lock_buffer(bh);
3210
3211 /*
3212 * If the buffer has the write error flag, we have failed
3213 * to write out another inode in the same block. In this
3214 * case, we don't have to read the block because we may
3215 * read the old inode data successfully.
3216 */
3217 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
3218 set_buffer_uptodate(bh);
3219
3220 if (buffer_uptodate(bh)) {
3221 /* someone brought it uptodate while we waited */
3222 unlock_buffer(bh);
3223 goto has_buffer;
3224 }
3225
3226 /*
3227 * If we have all information of the inode in memory and this
3228 * is the only valid inode in the block, we need not read the
3229 * block.
3230 */
3231 if (in_mem) {
3232 struct buffer_head *bitmap_bh;
3233 int i, start;
3234
3235 start = inode_offset & ~(inodes_per_block - 1);
3236
3237 /* Is the inode bitmap in cache? */
3238 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
3239 if (!bitmap_bh)
3240 goto make_io;
3241
3242 /*
3243 * If the inode bitmap isn't in cache then the
3244 * optimisation may end up performing two reads instead
3245 * of one, so skip it.
3246 */
3247 if (!buffer_uptodate(bitmap_bh)) {
3248 brelse(bitmap_bh);
3249 goto make_io;
3250 }
3251 for (i = start; i < start + inodes_per_block; i++) {
3252 if (i == inode_offset)
3253 continue;
3254 if (ext4_test_bit(i, bitmap_bh->b_data))
3255 break;
3256 }
3257 brelse(bitmap_bh);
3258 if (i == start + inodes_per_block) {
3259 /* all other inodes are free, so skip I/O */
3260 memset(bh->b_data, 0, bh->b_size);
3261 set_buffer_uptodate(bh);
3262 unlock_buffer(bh);
3263 goto has_buffer;
3264 }
3265 }
3266
3267make_io:
3268 /*
3269 * If we need to do any I/O, try to pre-readahead extra
3270 * blocks from the inode table.
3271 */
3272 if (EXT4_SB(sb)->s_inode_readahead_blks) {
3273 ext4_fsblk_t b, end, table;
3274 unsigned num;
3275
3276 table = ext4_inode_table(sb, gdp);
3277 /* s_inode_readahead_blks is always a power of 2 */
3278 b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
3279 if (table > b)
3280 b = table;
3281 end = b + EXT4_SB(sb)->s_inode_readahead_blks;
3282 num = EXT4_INODES_PER_GROUP(sb);
3283 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3284 EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
3285 num -= ext4_itable_unused_count(sb, gdp);
3286 table += num / inodes_per_block;
3287 if (end > table)
3288 end = table;
3289 while (b <= end)
3290 sb_breadahead(sb, b++);
3291 }
3292
3293 /*
3294 * There are other valid inodes in the buffer, this inode
3295 * has in-inode xattrs, or we don't have this inode in memory.
3296 * Read the block from disk.
3297 */
3298 trace_ext4_load_inode(inode);
3299 get_bh(bh);
3300 bh->b_end_io = end_buffer_read_sync;
3301 submit_bh(READ | REQ_META | REQ_PRIO, bh);
3302 wait_on_buffer(bh);
3303 if (!buffer_uptodate(bh)) {
3304 EXT4_ERROR_INODE_BLOCK(inode, block,
3305 "unable to read itable block");
3306 brelse(bh);
3307 return -EIO;
3308 }
3309 }
3310has_buffer:
3311 iloc->bh = bh;
3312 return 0;
3313}
3314
3315int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
3316{
3317 /* We have all inode data except xattrs in memory here. */
3318 return __ext4_get_inode_loc(inode, iloc,
3319 !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
3320}
3321
3322void ext4_set_inode_flags(struct inode *inode)
3323{
3324 unsigned int flags = EXT4_I(inode)->i_flags;
3325
3326 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
3327 if (flags & EXT4_SYNC_FL)
3328 inode->i_flags |= S_SYNC;
3329 if (flags & EXT4_APPEND_FL)
3330 inode->i_flags |= S_APPEND;
3331 if (flags & EXT4_IMMUTABLE_FL)
3332 inode->i_flags |= S_IMMUTABLE;
3333 if (flags & EXT4_NOATIME_FL)
3334 inode->i_flags |= S_NOATIME;
3335 if (flags & EXT4_DIRSYNC_FL)
3336 inode->i_flags |= S_DIRSYNC;
3337}
3338
3339/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
3340void ext4_get_inode_flags(struct ext4_inode_info *ei)
3341{
3342 unsigned int vfs_fl;
3343 unsigned long old_fl, new_fl;
3344
3345 do {
3346 vfs_fl = ei->vfs_inode.i_flags;
3347 old_fl = ei->i_flags;
3348 new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
3349 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
3350 EXT4_DIRSYNC_FL);
3351 if (vfs_fl & S_SYNC)
3352 new_fl |= EXT4_SYNC_FL;
3353 if (vfs_fl & S_APPEND)
3354 new_fl |= EXT4_APPEND_FL;
3355 if (vfs_fl & S_IMMUTABLE)
3356 new_fl |= EXT4_IMMUTABLE_FL;
3357 if (vfs_fl & S_NOATIME)
3358 new_fl |= EXT4_NOATIME_FL;
3359 if (vfs_fl & S_DIRSYNC)
3360 new_fl |= EXT4_DIRSYNC_FL;
3361 } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
3362}
3363
3364static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
3365 struct ext4_inode_info *ei)
3366{
3367 blkcnt_t i_blocks ;
3368 struct inode *inode = &(ei->vfs_inode);
3369 struct super_block *sb = inode->i_sb;
3370
3371 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3372 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
3373 /* we are using combined 48 bit field */
3374 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
3375 le32_to_cpu(raw_inode->i_blocks_lo);
3376 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
3377 /* i_blocks represent file system block size */
3378 return i_blocks << (inode->i_blkbits - 9);
3379 } else {
3380 return i_blocks;
3381 }
3382 } else {
3383 return le32_to_cpu(raw_inode->i_blocks_lo);
3384 }
3385}
3386
3387struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
3388{
3389 struct ext4_iloc iloc;
3390 struct ext4_inode *raw_inode;
3391 struct ext4_inode_info *ei;
3392 struct inode *inode;
3393 journal_t *journal = EXT4_SB(sb)->s_journal;
3394 long ret;
3395 int block;
3396
3397 inode = iget_locked(sb, ino);
3398 if (!inode)
3399 return ERR_PTR(-ENOMEM);
3400 if (!(inode->i_state & I_NEW))
3401 return inode;
3402
3403 ei = EXT4_I(inode);
3404 iloc.bh = NULL;
3405
3406 ret = __ext4_get_inode_loc(inode, &iloc, 0);
3407 if (ret < 0)
3408 goto bad_inode;
3409 raw_inode = ext4_raw_inode(&iloc);
3410 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
3411 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
3412 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
3413 if (!(test_opt(inode->i_sb, NO_UID32))) {
3414 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
3415 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
3416 }
3417 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
3418
3419 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
3420 ei->i_dir_start_lookup = 0;
3421 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
3422 /* We now have enough fields to check if the inode was active or not.
3423 * This is needed because nfsd might try to access dead inodes
3424 * the test is that same one that e2fsck uses
3425 * NeilBrown 1999oct15
3426 */
3427 if (inode->i_nlink == 0) {
3428 if (inode->i_mode == 0 ||
3429 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
3430 /* this inode is deleted */
3431 ret = -ESTALE;
3432 goto bad_inode;
3433 }
3434 /* The only unlinked inodes we let through here have
3435 * valid i_mode and are being read by the orphan
3436 * recovery code: that's fine, we're about to complete
3437 * the process of deleting those. */
3438 }
3439 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
3440 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
3441 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
3442 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
3443 ei->i_file_acl |=
3444 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
3445 inode->i_size = ext4_isize(raw_inode);
3446 ei->i_disksize = inode->i_size;
3447#ifdef CONFIG_QUOTA
3448 ei->i_reserved_quota = 0;
3449#endif
3450 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
3451 ei->i_block_group = iloc.block_group;
3452 ei->i_last_alloc_group = ~0;
3453 /*
3454 * NOTE! The in-memory inode i_data array is in little-endian order
3455 * even on big-endian machines: we do NOT byteswap the block numbers!
3456 */
3457 for (block = 0; block < EXT4_N_BLOCKS; block++)
3458 ei->i_data[block] = raw_inode->i_block[block];
3459 INIT_LIST_HEAD(&ei->i_orphan);
3460
3461 /*
3462 * Set transaction id's of transactions that have to be committed
3463 * to finish f[data]sync. We set them to currently running transaction
3464 * as we cannot be sure that the inode or some of its metadata isn't
3465 * part of the transaction - the inode could have been reclaimed and
3466 * now it is reread from disk.
3467 */
3468 if (journal) {
3469 transaction_t *transaction;
3470 tid_t tid;
3471
3472 read_lock(&journal->j_state_lock);
3473 if (journal->j_running_transaction)
3474 transaction = journal->j_running_transaction;
3475 else
3476 transaction = journal->j_committing_transaction;
3477 if (transaction)
3478 tid = transaction->t_tid;
3479 else
3480 tid = journal->j_commit_sequence;
3481 read_unlock(&journal->j_state_lock);
3482 ei->i_sync_tid = tid;
3483 ei->i_datasync_tid = tid;
3484 }
3485
3486 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3487 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
3488 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
3489 EXT4_INODE_SIZE(inode->i_sb)) {
3490 ret = -EIO;
3491 goto bad_inode;
3492 }
3493 if (ei->i_extra_isize == 0) {
3494 /* The extra space is currently unused. Use it. */
3495 ei->i_extra_isize = sizeof(struct ext4_inode) -
3496 EXT4_GOOD_OLD_INODE_SIZE;
3497 } else {
3498 __le32 *magic = (void *)raw_inode +
3499 EXT4_GOOD_OLD_INODE_SIZE +
3500 ei->i_extra_isize;
3501 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
3502 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
3503 }
3504 } else
3505 ei->i_extra_isize = 0;
3506
3507 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
3508 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
3509 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
3510 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
3511
3512 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
3513 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3514 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
3515 inode->i_version |=
3516 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
3517 }
3518
3519 ret = 0;
3520 if (ei->i_file_acl &&
3521 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
3522 EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
3523 ei->i_file_acl);
3524 ret = -EIO;
3525 goto bad_inode;
3526 } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
3527 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3528 (S_ISLNK(inode->i_mode) &&
3529 !ext4_inode_is_fast_symlink(inode)))
3530 /* Validate extent which is part of inode */
3531 ret = ext4_ext_check_inode(inode);
3532 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3533 (S_ISLNK(inode->i_mode) &&
3534 !ext4_inode_is_fast_symlink(inode))) {
3535 /* Validate block references which are part of inode */
3536 ret = ext4_ind_check_inode(inode);
3537 }
3538 if (ret)
3539 goto bad_inode;
3540
3541 if (S_ISREG(inode->i_mode)) {
3542 inode->i_op = &ext4_file_inode_operations;
3543 inode->i_fop = &ext4_file_operations;
3544 ext4_set_aops(inode);
3545 } else if (S_ISDIR(inode->i_mode)) {
3546 inode->i_op = &ext4_dir_inode_operations;
3547 inode->i_fop = &ext4_dir_operations;
3548 } else if (S_ISLNK(inode->i_mode)) {
3549 if (ext4_inode_is_fast_symlink(inode)) {
3550 inode->i_op = &ext4_fast_symlink_inode_operations;
3551 nd_terminate_link(ei->i_data, inode->i_size,
3552 sizeof(ei->i_data) - 1);
3553 } else {
3554 inode->i_op = &ext4_symlink_inode_operations;
3555 ext4_set_aops(inode);
3556 }
3557 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
3558 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
3559 inode->i_op = &ext4_special_inode_operations;
3560 if (raw_inode->i_block[0])
3561 init_special_inode(inode, inode->i_mode,
3562 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3563 else
3564 init_special_inode(inode, inode->i_mode,
3565 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3566 } else {
3567 ret = -EIO;
3568 EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
3569 goto bad_inode;
3570 }
3571 brelse(iloc.bh);
3572 ext4_set_inode_flags(inode);
3573 unlock_new_inode(inode);
3574 return inode;
3575
3576bad_inode:
3577 brelse(iloc.bh);
3578 iget_failed(inode);
3579 return ERR_PTR(ret);
3580}
3581
3582static int ext4_inode_blocks_set(handle_t *handle,
3583 struct ext4_inode *raw_inode,
3584 struct ext4_inode_info *ei)
3585{
3586 struct inode *inode = &(ei->vfs_inode);
3587 u64 i_blocks = inode->i_blocks;
3588 struct super_block *sb = inode->i_sb;
3589
3590 if (i_blocks <= ~0U) {
3591 /*
3592 * i_blocks can be represnted in a 32 bit variable
3593 * as multiple of 512 bytes
3594 */
3595 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3596 raw_inode->i_blocks_high = 0;
3597 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
3598 return 0;
3599 }
3600 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
3601 return -EFBIG;
3602
3603 if (i_blocks <= 0xffffffffffffULL) {
3604 /*
3605 * i_blocks can be represented in a 48 bit variable
3606 * as multiple of 512 bytes
3607 */
3608 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3609 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
3610 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
3611 } else {
3612 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
3613 /* i_block is stored in file system block size */
3614 i_blocks = i_blocks >> (inode->i_blkbits - 9);
3615 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3616 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
3617 }
3618 return 0;
3619}
3620
3621/*
3622 * Post the struct inode info into an on-disk inode location in the
3623 * buffer-cache. This gobbles the caller's reference to the
3624 * buffer_head in the inode location struct.
3625 *
3626 * The caller must have write access to iloc->bh.
3627 */
3628static int ext4_do_update_inode(handle_t *handle,
3629 struct inode *inode,
3630 struct ext4_iloc *iloc)
3631{
3632 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
3633 struct ext4_inode_info *ei = EXT4_I(inode);
3634 struct buffer_head *bh = iloc->bh;
3635 int err = 0, rc, block;
3636
3637 /* For fields not not tracking in the in-memory inode,
3638 * initialise them to zero for new inodes. */
3639 if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
3640 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
3641
3642 ext4_get_inode_flags(ei);
3643 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3644 if (!(test_opt(inode->i_sb, NO_UID32))) {
3645 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
3646 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
3647/*
3648 * Fix up interoperability with old kernels. Otherwise, old inodes get
3649 * re-used with the upper 16 bits of the uid/gid intact
3650 */
3651 if (!ei->i_dtime) {
3652 raw_inode->i_uid_high =
3653 cpu_to_le16(high_16_bits(inode->i_uid));
3654 raw_inode->i_gid_high =
3655 cpu_to_le16(high_16_bits(inode->i_gid));
3656 } else {
3657 raw_inode->i_uid_high = 0;
3658 raw_inode->i_gid_high = 0;
3659 }
3660 } else {
3661 raw_inode->i_uid_low =
3662 cpu_to_le16(fs_high2lowuid(inode->i_uid));
3663 raw_inode->i_gid_low =
3664 cpu_to_le16(fs_high2lowgid(inode->i_gid));
3665 raw_inode->i_uid_high = 0;
3666 raw_inode->i_gid_high = 0;
3667 }
3668 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
3669
3670 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
3671 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
3672 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
3673 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
3674
3675 if (ext4_inode_blocks_set(handle, raw_inode, ei))
3676 goto out_brelse;
3677 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3678 raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
3679 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
3680 cpu_to_le32(EXT4_OS_HURD))
3681 raw_inode->i_file_acl_high =
3682 cpu_to_le16(ei->i_file_acl >> 32);
3683 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
3684 ext4_isize_set(raw_inode, ei->i_disksize);
3685 if (ei->i_disksize > 0x7fffffffULL) {
3686 struct super_block *sb = inode->i_sb;
3687 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
3688 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
3689 EXT4_SB(sb)->s_es->s_rev_level ==
3690 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
3691 /* If this is the first large file
3692 * created, add a flag to the superblock.
3693 */
3694 err = ext4_journal_get_write_access(handle,
3695 EXT4_SB(sb)->s_sbh);
3696 if (err)
3697 goto out_brelse;
3698 ext4_update_dynamic_rev(sb);
3699 EXT4_SET_RO_COMPAT_FEATURE(sb,
3700 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
3701 sb->s_dirt = 1;
3702 ext4_handle_sync(handle);
3703 err = ext4_handle_dirty_metadata(handle, NULL,
3704 EXT4_SB(sb)->s_sbh);
3705 }
3706 }
3707 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
3708 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
3709 if (old_valid_dev(inode->i_rdev)) {
3710 raw_inode->i_block[0] =
3711 cpu_to_le32(old_encode_dev(inode->i_rdev));
3712 raw_inode->i_block[1] = 0;
3713 } else {
3714 raw_inode->i_block[0] = 0;
3715 raw_inode->i_block[1] =
3716 cpu_to_le32(new_encode_dev(inode->i_rdev));
3717 raw_inode->i_block[2] = 0;
3718 }
3719 } else
3720 for (block = 0; block < EXT4_N_BLOCKS; block++)
3721 raw_inode->i_block[block] = ei->i_data[block];
3722
3723 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
3724 if (ei->i_extra_isize) {
3725 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
3726 raw_inode->i_version_hi =
3727 cpu_to_le32(inode->i_version >> 32);
3728 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3729 }
3730
3731 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
3732 rc = ext4_handle_dirty_metadata(handle, NULL, bh);
3733 if (!err)
3734 err = rc;
3735 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
3736
3737 ext4_update_inode_fsync_trans(handle, inode, 0);
3738out_brelse:
3739 brelse(bh);
3740 ext4_std_error(inode->i_sb, err);
3741 return err;
3742}
3743
3744/*
3745 * ext4_write_inode()
3746 *
3747 * We are called from a few places:
3748 *
3749 * - Within generic_file_write() for O_SYNC files.
3750 * Here, there will be no transaction running. We wait for any running
3751 * trasnaction to commit.
3752 *
3753 * - Within sys_sync(), kupdate and such.
3754 * We wait on commit, if tol to.
3755 *
3756 * - Within prune_icache() (PF_MEMALLOC == true)
3757 * Here we simply return. We can't afford to block kswapd on the
3758 * journal commit.
3759 *
3760 * In all cases it is actually safe for us to return without doing anything,
3761 * because the inode has been copied into a raw inode buffer in
3762 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
3763 * knfsd.
3764 *
3765 * Note that we are absolutely dependent upon all inode dirtiers doing the
3766 * right thing: they *must* call mark_inode_dirty() after dirtying info in
3767 * which we are interested.
3768 *
3769 * It would be a bug for them to not do this. The code:
3770 *
3771 * mark_inode_dirty(inode)
3772 * stuff();
3773 * inode->i_size = expr;
3774 *
3775 * is in error because a kswapd-driven write_inode() could occur while
3776 * `stuff()' is running, and the new i_size will be lost. Plus the inode
3777 * will no longer be on the superblock's dirty inode list.
3778 */
3779int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
3780{
3781 int err;
3782
3783 if (current->flags & PF_MEMALLOC)
3784 return 0;
3785
3786 if (EXT4_SB(inode->i_sb)->s_journal) {
3787 if (ext4_journal_current_handle()) {
3788 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3789 dump_stack();
3790 return -EIO;
3791 }
3792
3793 if (wbc->sync_mode != WB_SYNC_ALL)
3794 return 0;
3795
3796 err = ext4_force_commit(inode->i_sb);
3797 } else {
3798 struct ext4_iloc iloc;
3799
3800 err = __ext4_get_inode_loc(inode, &iloc, 0);
3801 if (err)
3802 return err;
3803 if (wbc->sync_mode == WB_SYNC_ALL)
3804 sync_dirty_buffer(iloc.bh);
3805 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
3806 EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
3807 "IO error syncing inode");
3808 err = -EIO;
3809 }
3810 brelse(iloc.bh);
3811 }
3812 return err;
3813}
3814
3815/*
3816 * ext4_setattr()
3817 *
3818 * Called from notify_change.
3819 *
3820 * We want to trap VFS attempts to truncate the file as soon as
3821 * possible. In particular, we want to make sure that when the VFS
3822 * shrinks i_size, we put the inode on the orphan list and modify
3823 * i_disksize immediately, so that during the subsequent flushing of
3824 * dirty pages and freeing of disk blocks, we can guarantee that any
3825 * commit will leave the blocks being flushed in an unused state on
3826 * disk. (On recovery, the inode will get truncated and the blocks will
3827 * be freed, so we have a strong guarantee that no future commit will
3828 * leave these blocks visible to the user.)
3829 *
3830 * Another thing we have to assure is that if we are in ordered mode
3831 * and inode is still attached to the committing transaction, we must
3832 * we start writeout of all the dirty pages which are being truncated.
3833 * This way we are sure that all the data written in the previous
3834 * transaction are already on disk (truncate waits for pages under
3835 * writeback).
3836 *
3837 * Called with inode->i_mutex down.
3838 */
3839int ext4_setattr(struct dentry *dentry, struct iattr *attr)
3840{
3841 struct inode *inode = dentry->d_inode;
3842 int error, rc = 0;
3843 int orphan = 0;
3844 const unsigned int ia_valid = attr->ia_valid;
3845
3846 error = inode_change_ok(inode, attr);
3847 if (error)
3848 return error;
3849
3850 if (is_quota_modification(inode, attr))
3851 dquot_initialize(inode);
3852 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
3853 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
3854 handle_t *handle;
3855
3856 /* (user+group)*(old+new) structure, inode write (sb,
3857 * inode block, ? - but truncate inode update has it) */
3858 handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
3859 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3);
3860 if (IS_ERR(handle)) {
3861 error = PTR_ERR(handle);
3862 goto err_out;
3863 }
3864 error = dquot_transfer(inode, attr);
3865 if (error) {
3866 ext4_journal_stop(handle);
3867 return error;
3868 }
3869 /* Update corresponding info in inode so that everything is in
3870 * one transaction */
3871 if (attr->ia_valid & ATTR_UID)
3872 inode->i_uid = attr->ia_uid;
3873 if (attr->ia_valid & ATTR_GID)
3874 inode->i_gid = attr->ia_gid;
3875 error = ext4_mark_inode_dirty(handle, inode);
3876 ext4_journal_stop(handle);
3877 }
3878
3879 if (attr->ia_valid & ATTR_SIZE) {
3880 inode_dio_wait(inode);
3881
3882 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3883 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3884
3885 if (attr->ia_size > sbi->s_bitmap_maxbytes)
3886 return -EFBIG;
3887 }
3888 }
3889
3890 if (S_ISREG(inode->i_mode) &&
3891 attr->ia_valid & ATTR_SIZE &&
3892 (attr->ia_size < inode->i_size)) {
3893 handle_t *handle;
3894
3895 handle = ext4_journal_start(inode, 3);
3896 if (IS_ERR(handle)) {
3897 error = PTR_ERR(handle);
3898 goto err_out;
3899 }
3900 if (ext4_handle_valid(handle)) {
3901 error = ext4_orphan_add(handle, inode);
3902 orphan = 1;
3903 }
3904 EXT4_I(inode)->i_disksize = attr->ia_size;
3905 rc = ext4_mark_inode_dirty(handle, inode);
3906 if (!error)
3907 error = rc;
3908 ext4_journal_stop(handle);
3909
3910 if (ext4_should_order_data(inode)) {
3911 error = ext4_begin_ordered_truncate(inode,
3912 attr->ia_size);
3913 if (error) {
3914 /* Do as much error cleanup as possible */
3915 handle = ext4_journal_start(inode, 3);
3916 if (IS_ERR(handle)) {
3917 ext4_orphan_del(NULL, inode);
3918 goto err_out;
3919 }
3920 ext4_orphan_del(handle, inode);
3921 orphan = 0;
3922 ext4_journal_stop(handle);
3923 goto err_out;
3924 }
3925 }
3926 }
3927
3928 if (attr->ia_valid & ATTR_SIZE) {
3929 if (attr->ia_size != i_size_read(inode)) {
3930 truncate_setsize(inode, attr->ia_size);
3931 ext4_truncate(inode);
3932 } else if (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3933 ext4_truncate(inode);
3934 }
3935
3936 if (!rc) {
3937 setattr_copy(inode, attr);
3938 mark_inode_dirty(inode);
3939 }
3940
3941 /*
3942 * If the call to ext4_truncate failed to get a transaction handle at
3943 * all, we need to clean up the in-core orphan list manually.
3944 */
3945 if (orphan && inode->i_nlink)
3946 ext4_orphan_del(NULL, inode);
3947
3948 if (!rc && (ia_valid & ATTR_MODE))
3949 rc = ext4_acl_chmod(inode);
3950
3951err_out:
3952 ext4_std_error(inode->i_sb, error);
3953 if (!error)
3954 error = rc;
3955 return error;
3956}
3957
3958int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
3959 struct kstat *stat)
3960{
3961 struct inode *inode;
3962 unsigned long delalloc_blocks;
3963
3964 inode = dentry->d_inode;
3965 generic_fillattr(inode, stat);
3966
3967 /*
3968 * We can't update i_blocks if the block allocation is delayed
3969 * otherwise in the case of system crash before the real block
3970 * allocation is done, we will have i_blocks inconsistent with
3971 * on-disk file blocks.
3972 * We always keep i_blocks updated together with real
3973 * allocation. But to not confuse with user, stat
3974 * will return the blocks that include the delayed allocation
3975 * blocks for this file.
3976 */
3977 delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
3978
3979 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
3980 return 0;
3981}
3982
3983static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
3984{
3985 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
3986 return ext4_ind_trans_blocks(inode, nrblocks, chunk);
3987 return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
3988}
3989
3990/*
3991 * Account for index blocks, block groups bitmaps and block group
3992 * descriptor blocks if modify datablocks and index blocks
3993 * worse case, the indexs blocks spread over different block groups
3994 *
3995 * If datablocks are discontiguous, they are possible to spread over
3996 * different block groups too. If they are contiuguous, with flexbg,
3997 * they could still across block group boundary.
3998 *
3999 * Also account for superblock, inode, quota and xattr blocks
4000 */
4001static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4002{
4003 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
4004 int gdpblocks;
4005 int idxblocks;
4006 int ret = 0;
4007
4008 /*
4009 * How many index blocks need to touch to modify nrblocks?
4010 * The "Chunk" flag indicating whether the nrblocks is
4011 * physically contiguous on disk
4012 *
4013 * For Direct IO and fallocate, they calls get_block to allocate
4014 * one single extent at a time, so they could set the "Chunk" flag
4015 */
4016 idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
4017
4018 ret = idxblocks;
4019
4020 /*
4021 * Now let's see how many group bitmaps and group descriptors need
4022 * to account
4023 */
4024 groups = idxblocks;
4025 if (chunk)
4026 groups += 1;
4027 else
4028 groups += nrblocks;
4029
4030 gdpblocks = groups;
4031 if (groups > ngroups)
4032 groups = ngroups;
4033 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
4034 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
4035
4036 /* bitmaps and block group descriptor blocks */
4037 ret += groups + gdpblocks;
4038
4039 /* Blocks for super block, inode, quota and xattr blocks */
4040 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
4041
4042 return ret;
4043}
4044
4045/*
4046 * Calculate the total number of credits to reserve to fit
4047 * the modification of a single pages into a single transaction,
4048 * which may include multiple chunks of block allocations.
4049 *
4050 * This could be called via ext4_write_begin()
4051 *
4052 * We need to consider the worse case, when
4053 * one new block per extent.
4054 */
4055int ext4_writepage_trans_blocks(struct inode *inode)
4056{
4057 int bpp = ext4_journal_blocks_per_page(inode);
4058 int ret;
4059
4060 ret = ext4_meta_trans_blocks(inode, bpp, 0);
4061
4062 /* Account for data blocks for journalled mode */
4063 if (ext4_should_journal_data(inode))
4064 ret += bpp;
4065 return ret;
4066}
4067
4068/*
4069 * Calculate the journal credits for a chunk of data modification.
4070 *
4071 * This is called from DIO, fallocate or whoever calling
4072 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
4073 *
4074 * journal buffers for data blocks are not included here, as DIO
4075 * and fallocate do no need to journal data buffers.
4076 */
4077int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
4078{
4079 return ext4_meta_trans_blocks(inode, nrblocks, 1);
4080}
4081
4082/*
4083 * The caller must have previously called ext4_reserve_inode_write().
4084 * Give this, we know that the caller already has write access to iloc->bh.
4085 */
4086int ext4_mark_iloc_dirty(handle_t *handle,
4087 struct inode *inode, struct ext4_iloc *iloc)
4088{
4089 int err = 0;
4090
4091 if (test_opt(inode->i_sb, I_VERSION))
4092 inode_inc_iversion(inode);
4093
4094 /* the do_update_inode consumes one bh->b_count */
4095 get_bh(iloc->bh);
4096
4097 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4098 err = ext4_do_update_inode(handle, inode, iloc);
4099 put_bh(iloc->bh);
4100 return err;
4101}
4102
4103/*
4104 * On success, We end up with an outstanding reference count against
4105 * iloc->bh. This _must_ be cleaned up later.
4106 */
4107
4108int
4109ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
4110 struct ext4_iloc *iloc)
4111{
4112 int err;
4113
4114 err = ext4_get_inode_loc(inode, iloc);
4115 if (!err) {
4116 BUFFER_TRACE(iloc->bh, "get_write_access");
4117 err = ext4_journal_get_write_access(handle, iloc->bh);
4118 if (err) {
4119 brelse(iloc->bh);
4120 iloc->bh = NULL;
4121 }
4122 }
4123 ext4_std_error(inode->i_sb, err);
4124 return err;
4125}
4126
4127/*
4128 * Expand an inode by new_extra_isize bytes.
4129 * Returns 0 on success or negative error number on failure.
4130 */
4131static int ext4_expand_extra_isize(struct inode *inode,
4132 unsigned int new_extra_isize,
4133 struct ext4_iloc iloc,
4134 handle_t *handle)
4135{
4136 struct ext4_inode *raw_inode;
4137 struct ext4_xattr_ibody_header *header;
4138
4139 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
4140 return 0;
4141
4142 raw_inode = ext4_raw_inode(&iloc);
4143
4144 header = IHDR(inode, raw_inode);
4145
4146 /* No extended attributes present */
4147 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
4148 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
4149 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
4150 new_extra_isize);
4151 EXT4_I(inode)->i_extra_isize = new_extra_isize;
4152 return 0;
4153 }
4154
4155 /* try to expand with EAs present */
4156 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
4157 raw_inode, handle);
4158}
4159
4160/*
4161 * What we do here is to mark the in-core inode as clean with respect to inode
4162 * dirtiness (it may still be data-dirty).
4163 * This means that the in-core inode may be reaped by prune_icache
4164 * without having to perform any I/O. This is a very good thing,
4165 * because *any* task may call prune_icache - even ones which
4166 * have a transaction open against a different journal.
4167 *
4168 * Is this cheating? Not really. Sure, we haven't written the
4169 * inode out, but prune_icache isn't a user-visible syncing function.
4170 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
4171 * we start and wait on commits.
4172 *
4173 * Is this efficient/effective? Well, we're being nice to the system
4174 * by cleaning up our inodes proactively so they can be reaped
4175 * without I/O. But we are potentially leaving up to five seconds'
4176 * worth of inodes floating about which prune_icache wants us to
4177 * write out. One way to fix that would be to get prune_icache()
4178 * to do a write_super() to free up some memory. It has the desired
4179 * effect.
4180 */
4181int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4182{
4183 struct ext4_iloc iloc;
4184 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4185 static unsigned int mnt_count;
4186 int err, ret;
4187
4188 might_sleep();
4189 trace_ext4_mark_inode_dirty(inode, _RET_IP_);
4190 err = ext4_reserve_inode_write(handle, inode, &iloc);
4191 if (ext4_handle_valid(handle) &&
4192 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
4193 !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
4194 /*
4195 * We need extra buffer credits since we may write into EA block
4196 * with this same handle. If journal_extend fails, then it will
4197 * only result in a minor loss of functionality for that inode.
4198 * If this is felt to be critical, then e2fsck should be run to
4199 * force a large enough s_min_extra_isize.
4200 */
4201 if ((jbd2_journal_extend(handle,
4202 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
4203 ret = ext4_expand_extra_isize(inode,
4204 sbi->s_want_extra_isize,
4205 iloc, handle);
4206 if (ret) {
4207 ext4_set_inode_state(inode,
4208 EXT4_STATE_NO_EXPAND);
4209 if (mnt_count !=
4210 le16_to_cpu(sbi->s_es->s_mnt_count)) {
4211 ext4_warning(inode->i_sb,
4212 "Unable to expand inode %lu. Delete"
4213 " some EAs or run e2fsck.",
4214 inode->i_ino);
4215 mnt_count =
4216 le16_to_cpu(sbi->s_es->s_mnt_count);
4217 }
4218 }
4219 }
4220 }
4221 if (!err)
4222 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
4223 return err;
4224}
4225
4226/*
4227 * ext4_dirty_inode() is called from __mark_inode_dirty()
4228 *
4229 * We're really interested in the case where a file is being extended.
4230 * i_size has been changed by generic_commit_write() and we thus need
4231 * to include the updated inode in the current transaction.
4232 *
4233 * Also, dquot_alloc_block() will always dirty the inode when blocks
4234 * are allocated to the file.
4235 *
4236 * If the inode is marked synchronous, we don't honour that here - doing
4237 * so would cause a commit on atime updates, which we don't bother doing.
4238 * We handle synchronous inodes at the highest possible level.
4239 */
4240void ext4_dirty_inode(struct inode *inode, int flags)
4241{
4242 handle_t *handle;
4243
4244 handle = ext4_journal_start(inode, 2);
4245 if (IS_ERR(handle))
4246 goto out;
4247
4248 ext4_mark_inode_dirty(handle, inode);
4249
4250 ext4_journal_stop(handle);
4251out:
4252 return;
4253}
4254
4255#if 0
4256/*
4257 * Bind an inode's backing buffer_head into this transaction, to prevent
4258 * it from being flushed to disk early. Unlike
4259 * ext4_reserve_inode_write, this leaves behind no bh reference and
4260 * returns no iloc structure, so the caller needs to repeat the iloc
4261 * lookup to mark the inode dirty later.
4262 */
4263static int ext4_pin_inode(handle_t *handle, struct inode *inode)
4264{
4265 struct ext4_iloc iloc;
4266
4267 int err = 0;
4268 if (handle) {
4269 err = ext4_get_inode_loc(inode, &iloc);
4270 if (!err) {
4271 BUFFER_TRACE(iloc.bh, "get_write_access");
4272 err = jbd2_journal_get_write_access(handle, iloc.bh);
4273 if (!err)
4274 err = ext4_handle_dirty_metadata(handle,
4275 NULL,
4276 iloc.bh);
4277 brelse(iloc.bh);
4278 }
4279 }
4280 ext4_std_error(inode->i_sb, err);
4281 return err;
4282}
4283#endif
4284
4285int ext4_change_inode_journal_flag(struct inode *inode, int val)
4286{
4287 journal_t *journal;
4288 handle_t *handle;
4289 int err;
4290
4291 /*
4292 * We have to be very careful here: changing a data block's
4293 * journaling status dynamically is dangerous. If we write a
4294 * data block to the journal, change the status and then delete
4295 * that block, we risk forgetting to revoke the old log record
4296 * from the journal and so a subsequent replay can corrupt data.
4297 * So, first we make sure that the journal is empty and that
4298 * nobody is changing anything.
4299 */
4300
4301 journal = EXT4_JOURNAL(inode);
4302 if (!journal)
4303 return 0;
4304 if (is_journal_aborted(journal))
4305 return -EROFS;
4306
4307 jbd2_journal_lock_updates(journal);
4308 jbd2_journal_flush(journal);
4309
4310 /*
4311 * OK, there are no updates running now, and all cached data is
4312 * synced to disk. We are now in a completely consistent state
4313 * which doesn't have anything in the journal, and we know that
4314 * no filesystem updates are running, so it is safe to modify
4315 * the inode's in-core data-journaling state flag now.
4316 */
4317
4318 if (val)
4319 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
4320 else
4321 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
4322 ext4_set_aops(inode);
4323
4324 jbd2_journal_unlock_updates(journal);
4325
4326 /* Finally we can mark the inode as dirty. */
4327
4328 handle = ext4_journal_start(inode, 1);
4329 if (IS_ERR(handle))
4330 return PTR_ERR(handle);
4331
4332 err = ext4_mark_inode_dirty(handle, inode);
4333 ext4_handle_sync(handle);
4334 ext4_journal_stop(handle);
4335 ext4_std_error(inode->i_sb, err);
4336
4337 return err;
4338}
4339
4340static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
4341{
4342 return !buffer_mapped(bh);
4343}
4344
4345int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
4346{
4347 struct page *page = vmf->page;
4348 loff_t size;
4349 unsigned long len;
4350 int ret;
4351 struct file *file = vma->vm_file;
4352 struct inode *inode = file->f_path.dentry->d_inode;
4353 struct address_space *mapping = inode->i_mapping;
4354 handle_t *handle;
4355 get_block_t *get_block;
4356 int retries = 0;
4357
4358 /*
4359 * This check is racy but catches the common case. We rely on
4360 * __block_page_mkwrite() to do a reliable check.
4361 */
4362 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
4363 /* Delalloc case is easy... */
4364 if (test_opt(inode->i_sb, DELALLOC) &&
4365 !ext4_should_journal_data(inode) &&
4366 !ext4_nonda_switch(inode->i_sb)) {
4367 do {
4368 ret = __block_page_mkwrite(vma, vmf,
4369 ext4_da_get_block_prep);
4370 } while (ret == -ENOSPC &&
4371 ext4_should_retry_alloc(inode->i_sb, &retries));
4372 goto out_ret;
4373 }
4374
4375 lock_page(page);
4376 size = i_size_read(inode);
4377 /* Page got truncated from under us? */
4378 if (page->mapping != mapping || page_offset(page) > size) {
4379 unlock_page(page);
4380 ret = VM_FAULT_NOPAGE;
4381 goto out;
4382 }
4383
4384 if (page->index == size >> PAGE_CACHE_SHIFT)
4385 len = size & ~PAGE_CACHE_MASK;
4386 else
4387 len = PAGE_CACHE_SIZE;
4388 /*
4389 * Return if we have all the buffers mapped. This avoids the need to do
4390 * journal_start/journal_stop which can block and take a long time
4391 */
4392 if (page_has_buffers(page)) {
4393 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
4394 ext4_bh_unmapped)) {
4395 /* Wait so that we don't change page under IO */
4396 wait_on_page_writeback(page);
4397 ret = VM_FAULT_LOCKED;
4398 goto out;
4399 }
4400 }
4401 unlock_page(page);
4402 /* OK, we need to fill the hole... */
4403 if (ext4_should_dioread_nolock(inode))
4404 get_block = ext4_get_block_write;
4405 else
4406 get_block = ext4_get_block;
4407retry_alloc:
4408 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
4409 if (IS_ERR(handle)) {
4410 ret = VM_FAULT_SIGBUS;
4411 goto out;
4412 }
4413 ret = __block_page_mkwrite(vma, vmf, get_block);
4414 if (!ret && ext4_should_journal_data(inode)) {
4415 if (walk_page_buffers(handle, page_buffers(page), 0,
4416 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {
4417 unlock_page(page);
4418 ret = VM_FAULT_SIGBUS;
4419 goto out;
4420 }
4421 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
4422 }
4423 ext4_journal_stop(handle);
4424 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4425 goto retry_alloc;
4426out_ret:
4427 ret = block_page_mkwrite_return(ret);
4428out:
4429 return ret;
4430}
1/*
2 * linux/fs/ext4/inode.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * 64-bit file support on 64-bit platforms by Jakub Jelinek
16 * (jj@sunsite.ms.mff.cuni.cz)
17 *
18 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
19 */
20
21#include <linux/fs.h>
22#include <linux/time.h>
23#include <linux/jbd2.h>
24#include <linux/highuid.h>
25#include <linux/pagemap.h>
26#include <linux/quotaops.h>
27#include <linux/string.h>
28#include <linux/buffer_head.h>
29#include <linux/writeback.h>
30#include <linux/pagevec.h>
31#include <linux/mpage.h>
32#include <linux/namei.h>
33#include <linux/uio.h>
34#include <linux/bio.h>
35#include <linux/workqueue.h>
36#include <linux/kernel.h>
37#include <linux/printk.h>
38#include <linux/slab.h>
39#include <linux/ratelimit.h>
40
41#include "ext4_jbd2.h"
42#include "xattr.h"
43#include "acl.h"
44#include "truncate.h"
45
46#include <trace/events/ext4.h>
47
48#define MPAGE_DA_EXTENT_TAIL 0x01
49
50static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
51 struct ext4_inode_info *ei)
52{
53 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
54 __u16 csum_lo;
55 __u16 csum_hi = 0;
56 __u32 csum;
57
58 csum_lo = raw->i_checksum_lo;
59 raw->i_checksum_lo = 0;
60 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
61 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
62 csum_hi = raw->i_checksum_hi;
63 raw->i_checksum_hi = 0;
64 }
65
66 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw,
67 EXT4_INODE_SIZE(inode->i_sb));
68
69 raw->i_checksum_lo = csum_lo;
70 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
71 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
72 raw->i_checksum_hi = csum_hi;
73
74 return csum;
75}
76
77static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
78 struct ext4_inode_info *ei)
79{
80 __u32 provided, calculated;
81
82 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
83 cpu_to_le32(EXT4_OS_LINUX) ||
84 !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
85 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
86 return 1;
87
88 provided = le16_to_cpu(raw->i_checksum_lo);
89 calculated = ext4_inode_csum(inode, raw, ei);
90 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
91 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
92 provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
93 else
94 calculated &= 0xFFFF;
95
96 return provided == calculated;
97}
98
99static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
100 struct ext4_inode_info *ei)
101{
102 __u32 csum;
103
104 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
105 cpu_to_le32(EXT4_OS_LINUX) ||
106 !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
107 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
108 return;
109
110 csum = ext4_inode_csum(inode, raw, ei);
111 raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
112 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
113 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
114 raw->i_checksum_hi = cpu_to_le16(csum >> 16);
115}
116
117static inline int ext4_begin_ordered_truncate(struct inode *inode,
118 loff_t new_size)
119{
120 trace_ext4_begin_ordered_truncate(inode, new_size);
121 /*
122 * If jinode is zero, then we never opened the file for
123 * writing, so there's no need to call
124 * jbd2_journal_begin_ordered_truncate() since there's no
125 * outstanding writes we need to flush.
126 */
127 if (!EXT4_I(inode)->jinode)
128 return 0;
129 return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
130 EXT4_I(inode)->jinode,
131 new_size);
132}
133
134static void ext4_invalidatepage(struct page *page, unsigned long offset);
135static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
136 struct buffer_head *bh_result, int create);
137static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
138static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
139static int __ext4_journalled_writepage(struct page *page, unsigned int len);
140static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
141static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
142 struct inode *inode, struct page *page, loff_t from,
143 loff_t length, int flags);
144
145/*
146 * Test whether an inode is a fast symlink.
147 */
148static int ext4_inode_is_fast_symlink(struct inode *inode)
149{
150 int ea_blocks = EXT4_I(inode)->i_file_acl ?
151 (inode->i_sb->s_blocksize >> 9) : 0;
152
153 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
154}
155
156/*
157 * Restart the transaction associated with *handle. This does a commit,
158 * so before we call here everything must be consistently dirtied against
159 * this transaction.
160 */
161int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
162 int nblocks)
163{
164 int ret;
165
166 /*
167 * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
168 * moment, get_block can be called only for blocks inside i_size since
169 * page cache has been already dropped and writes are blocked by
170 * i_mutex. So we can safely drop the i_data_sem here.
171 */
172 BUG_ON(EXT4_JOURNAL(inode) == NULL);
173 jbd_debug(2, "restarting handle %p\n", handle);
174 up_write(&EXT4_I(inode)->i_data_sem);
175 ret = ext4_journal_restart(handle, nblocks);
176 down_write(&EXT4_I(inode)->i_data_sem);
177 ext4_discard_preallocations(inode);
178
179 return ret;
180}
181
182/*
183 * Called at the last iput() if i_nlink is zero.
184 */
185void ext4_evict_inode(struct inode *inode)
186{
187 handle_t *handle;
188 int err;
189
190 trace_ext4_evict_inode(inode);
191
192 ext4_ioend_wait(inode);
193
194 if (inode->i_nlink) {
195 /*
196 * When journalling data dirty buffers are tracked only in the
197 * journal. So although mm thinks everything is clean and
198 * ready for reaping the inode might still have some pages to
199 * write in the running transaction or waiting to be
200 * checkpointed. Thus calling jbd2_journal_invalidatepage()
201 * (via truncate_inode_pages()) to discard these buffers can
202 * cause data loss. Also even if we did not discard these
203 * buffers, we would have no way to find them after the inode
204 * is reaped and thus user could see stale data if he tries to
205 * read them before the transaction is checkpointed. So be
206 * careful and force everything to disk here... We use
207 * ei->i_datasync_tid to store the newest transaction
208 * containing inode's data.
209 *
210 * Note that directories do not have this problem because they
211 * don't use page cache.
212 */
213 if (ext4_should_journal_data(inode) &&
214 (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
215 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
216 tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
217
218 jbd2_log_start_commit(journal, commit_tid);
219 jbd2_log_wait_commit(journal, commit_tid);
220 filemap_write_and_wait(&inode->i_data);
221 }
222 truncate_inode_pages(&inode->i_data, 0);
223 goto no_delete;
224 }
225
226 if (!is_bad_inode(inode))
227 dquot_initialize(inode);
228
229 if (ext4_should_order_data(inode))
230 ext4_begin_ordered_truncate(inode, 0);
231 truncate_inode_pages(&inode->i_data, 0);
232
233 if (is_bad_inode(inode))
234 goto no_delete;
235
236 handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3);
237 if (IS_ERR(handle)) {
238 ext4_std_error(inode->i_sb, PTR_ERR(handle));
239 /*
240 * If we're going to skip the normal cleanup, we still need to
241 * make sure that the in-core orphan linked list is properly
242 * cleaned up.
243 */
244 ext4_orphan_del(NULL, inode);
245 goto no_delete;
246 }
247
248 if (IS_SYNC(inode))
249 ext4_handle_sync(handle);
250 inode->i_size = 0;
251 err = ext4_mark_inode_dirty(handle, inode);
252 if (err) {
253 ext4_warning(inode->i_sb,
254 "couldn't mark inode dirty (err %d)", err);
255 goto stop_handle;
256 }
257 if (inode->i_blocks)
258 ext4_truncate(inode);
259
260 /*
261 * ext4_ext_truncate() doesn't reserve any slop when it
262 * restarts journal transactions; therefore there may not be
263 * enough credits left in the handle to remove the inode from
264 * the orphan list and set the dtime field.
265 */
266 if (!ext4_handle_has_enough_credits(handle, 3)) {
267 err = ext4_journal_extend(handle, 3);
268 if (err > 0)
269 err = ext4_journal_restart(handle, 3);
270 if (err != 0) {
271 ext4_warning(inode->i_sb,
272 "couldn't extend journal (err %d)", err);
273 stop_handle:
274 ext4_journal_stop(handle);
275 ext4_orphan_del(NULL, inode);
276 goto no_delete;
277 }
278 }
279
280 /*
281 * Kill off the orphan record which ext4_truncate created.
282 * AKPM: I think this can be inside the above `if'.
283 * Note that ext4_orphan_del() has to be able to cope with the
284 * deletion of a non-existent orphan - this is because we don't
285 * know if ext4_truncate() actually created an orphan record.
286 * (Well, we could do this if we need to, but heck - it works)
287 */
288 ext4_orphan_del(handle, inode);
289 EXT4_I(inode)->i_dtime = get_seconds();
290
291 /*
292 * One subtle ordering requirement: if anything has gone wrong
293 * (transaction abort, IO errors, whatever), then we can still
294 * do these next steps (the fs will already have been marked as
295 * having errors), but we can't free the inode if the mark_dirty
296 * fails.
297 */
298 if (ext4_mark_inode_dirty(handle, inode))
299 /* If that failed, just do the required in-core inode clear. */
300 ext4_clear_inode(inode);
301 else
302 ext4_free_inode(handle, inode);
303 ext4_journal_stop(handle);
304 return;
305no_delete:
306 ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
307}
308
309#ifdef CONFIG_QUOTA
310qsize_t *ext4_get_reserved_space(struct inode *inode)
311{
312 return &EXT4_I(inode)->i_reserved_quota;
313}
314#endif
315
316/*
317 * Calculate the number of metadata blocks need to reserve
318 * to allocate a block located at @lblock
319 */
320static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
321{
322 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
323 return ext4_ext_calc_metadata_amount(inode, lblock);
324
325 return ext4_ind_calc_metadata_amount(inode, lblock);
326}
327
328/*
329 * Called with i_data_sem down, which is important since we can call
330 * ext4_discard_preallocations() from here.
331 */
332void ext4_da_update_reserve_space(struct inode *inode,
333 int used, int quota_claim)
334{
335 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
336 struct ext4_inode_info *ei = EXT4_I(inode);
337
338 spin_lock(&ei->i_block_reservation_lock);
339 trace_ext4_da_update_reserve_space(inode, used, quota_claim);
340 if (unlikely(used > ei->i_reserved_data_blocks)) {
341 ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
342 "with only %d reserved data blocks",
343 __func__, inode->i_ino, used,
344 ei->i_reserved_data_blocks);
345 WARN_ON(1);
346 used = ei->i_reserved_data_blocks;
347 }
348
349 if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) {
350 ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, allocated %d "
351 "with only %d reserved metadata blocks\n", __func__,
352 inode->i_ino, ei->i_allocated_meta_blocks,
353 ei->i_reserved_meta_blocks);
354 WARN_ON(1);
355 ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
356 }
357
358 /* Update per-inode reservations */
359 ei->i_reserved_data_blocks -= used;
360 ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
361 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
362 used + ei->i_allocated_meta_blocks);
363 ei->i_allocated_meta_blocks = 0;
364
365 if (ei->i_reserved_data_blocks == 0) {
366 /*
367 * We can release all of the reserved metadata blocks
368 * only when we have written all of the delayed
369 * allocation blocks.
370 */
371 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
372 ei->i_reserved_meta_blocks);
373 ei->i_reserved_meta_blocks = 0;
374 ei->i_da_metadata_calc_len = 0;
375 }
376 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
377
378 /* Update quota subsystem for data blocks */
379 if (quota_claim)
380 dquot_claim_block(inode, EXT4_C2B(sbi, used));
381 else {
382 /*
383 * We did fallocate with an offset that is already delayed
384 * allocated. So on delayed allocated writeback we should
385 * not re-claim the quota for fallocated blocks.
386 */
387 dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
388 }
389
390 /*
391 * If we have done all the pending block allocations and if
392 * there aren't any writers on the inode, we can discard the
393 * inode's preallocations.
394 */
395 if ((ei->i_reserved_data_blocks == 0) &&
396 (atomic_read(&inode->i_writecount) == 0))
397 ext4_discard_preallocations(inode);
398}
399
400static int __check_block_validity(struct inode *inode, const char *func,
401 unsigned int line,
402 struct ext4_map_blocks *map)
403{
404 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
405 map->m_len)) {
406 ext4_error_inode(inode, func, line, map->m_pblk,
407 "lblock %lu mapped to illegal pblock "
408 "(length %d)", (unsigned long) map->m_lblk,
409 map->m_len);
410 return -EIO;
411 }
412 return 0;
413}
414
415#define check_block_validity(inode, map) \
416 __check_block_validity((inode), __func__, __LINE__, (map))
417
418/*
419 * Return the number of contiguous dirty pages in a given inode
420 * starting at page frame idx.
421 */
422static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
423 unsigned int max_pages)
424{
425 struct address_space *mapping = inode->i_mapping;
426 pgoff_t index;
427 struct pagevec pvec;
428 pgoff_t num = 0;
429 int i, nr_pages, done = 0;
430
431 if (max_pages == 0)
432 return 0;
433 pagevec_init(&pvec, 0);
434 while (!done) {
435 index = idx;
436 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
437 PAGECACHE_TAG_DIRTY,
438 (pgoff_t)PAGEVEC_SIZE);
439 if (nr_pages == 0)
440 break;
441 for (i = 0; i < nr_pages; i++) {
442 struct page *page = pvec.pages[i];
443 struct buffer_head *bh, *head;
444
445 lock_page(page);
446 if (unlikely(page->mapping != mapping) ||
447 !PageDirty(page) ||
448 PageWriteback(page) ||
449 page->index != idx) {
450 done = 1;
451 unlock_page(page);
452 break;
453 }
454 if (page_has_buffers(page)) {
455 bh = head = page_buffers(page);
456 do {
457 if (!buffer_delay(bh) &&
458 !buffer_unwritten(bh))
459 done = 1;
460 bh = bh->b_this_page;
461 } while (!done && (bh != head));
462 }
463 unlock_page(page);
464 if (done)
465 break;
466 idx++;
467 num++;
468 if (num >= max_pages) {
469 done = 1;
470 break;
471 }
472 }
473 pagevec_release(&pvec);
474 }
475 return num;
476}
477
478/*
479 * Sets the BH_Da_Mapped bit on the buffer heads corresponding to the given map.
480 */
481static void set_buffers_da_mapped(struct inode *inode,
482 struct ext4_map_blocks *map)
483{
484 struct address_space *mapping = inode->i_mapping;
485 struct pagevec pvec;
486 int i, nr_pages;
487 pgoff_t index, end;
488
489 index = map->m_lblk >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
490 end = (map->m_lblk + map->m_len - 1) >>
491 (PAGE_CACHE_SHIFT - inode->i_blkbits);
492
493 pagevec_init(&pvec, 0);
494 while (index <= end) {
495 nr_pages = pagevec_lookup(&pvec, mapping, index,
496 min(end - index + 1,
497 (pgoff_t)PAGEVEC_SIZE));
498 if (nr_pages == 0)
499 break;
500 for (i = 0; i < nr_pages; i++) {
501 struct page *page = pvec.pages[i];
502 struct buffer_head *bh, *head;
503
504 if (unlikely(page->mapping != mapping) ||
505 !PageDirty(page))
506 break;
507
508 if (page_has_buffers(page)) {
509 bh = head = page_buffers(page);
510 do {
511 set_buffer_da_mapped(bh);
512 bh = bh->b_this_page;
513 } while (bh != head);
514 }
515 index++;
516 }
517 pagevec_release(&pvec);
518 }
519}
520
521/*
522 * The ext4_map_blocks() function tries to look up the requested blocks,
523 * and returns if the blocks are already mapped.
524 *
525 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
526 * and store the allocated blocks in the result buffer head and mark it
527 * mapped.
528 *
529 * If file type is extents based, it will call ext4_ext_map_blocks(),
530 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
531 * based files
532 *
533 * On success, it returns the number of blocks being mapped or allocate.
534 * if create==0 and the blocks are pre-allocated and uninitialized block,
535 * the result buffer head is unmapped. If the create ==1, it will make sure
536 * the buffer head is mapped.
537 *
538 * It returns 0 if plain look up failed (blocks have not been allocated), in
539 * that case, buffer head is unmapped
540 *
541 * It returns the error in case of allocation failure.
542 */
543int ext4_map_blocks(handle_t *handle, struct inode *inode,
544 struct ext4_map_blocks *map, int flags)
545{
546 int retval;
547
548 map->m_flags = 0;
549 ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
550 "logical block %lu\n", inode->i_ino, flags, map->m_len,
551 (unsigned long) map->m_lblk);
552 /*
553 * Try to see if we can get the block without requesting a new
554 * file system block.
555 */
556 down_read((&EXT4_I(inode)->i_data_sem));
557 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
558 retval = ext4_ext_map_blocks(handle, inode, map, flags &
559 EXT4_GET_BLOCKS_KEEP_SIZE);
560 } else {
561 retval = ext4_ind_map_blocks(handle, inode, map, flags &
562 EXT4_GET_BLOCKS_KEEP_SIZE);
563 }
564 up_read((&EXT4_I(inode)->i_data_sem));
565
566 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
567 int ret = check_block_validity(inode, map);
568 if (ret != 0)
569 return ret;
570 }
571
572 /* If it is only a block(s) look up */
573 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
574 return retval;
575
576 /*
577 * Returns if the blocks have already allocated
578 *
579 * Note that if blocks have been preallocated
580 * ext4_ext_get_block() returns the create = 0
581 * with buffer head unmapped.
582 */
583 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
584 return retval;
585
586 /*
587 * When we call get_blocks without the create flag, the
588 * BH_Unwritten flag could have gotten set if the blocks
589 * requested were part of a uninitialized extent. We need to
590 * clear this flag now that we are committed to convert all or
591 * part of the uninitialized extent to be an initialized
592 * extent. This is because we need to avoid the combination
593 * of BH_Unwritten and BH_Mapped flags being simultaneously
594 * set on the buffer_head.
595 */
596 map->m_flags &= ~EXT4_MAP_UNWRITTEN;
597
598 /*
599 * New blocks allocate and/or writing to uninitialized extent
600 * will possibly result in updating i_data, so we take
601 * the write lock of i_data_sem, and call get_blocks()
602 * with create == 1 flag.
603 */
604 down_write((&EXT4_I(inode)->i_data_sem));
605
606 /*
607 * if the caller is from delayed allocation writeout path
608 * we have already reserved fs blocks for allocation
609 * let the underlying get_block() function know to
610 * avoid double accounting
611 */
612 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
613 ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
614 /*
615 * We need to check for EXT4 here because migrate
616 * could have changed the inode type in between
617 */
618 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
619 retval = ext4_ext_map_blocks(handle, inode, map, flags);
620 } else {
621 retval = ext4_ind_map_blocks(handle, inode, map, flags);
622
623 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
624 /*
625 * We allocated new blocks which will result in
626 * i_data's format changing. Force the migrate
627 * to fail by clearing migrate flags
628 */
629 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
630 }
631
632 /*
633 * Update reserved blocks/metadata blocks after successful
634 * block allocation which had been deferred till now. We don't
635 * support fallocate for non extent files. So we can update
636 * reserve space here.
637 */
638 if ((retval > 0) &&
639 (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
640 ext4_da_update_reserve_space(inode, retval, 1);
641 }
642 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
643 ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
644
645 /* If we have successfully mapped the delayed allocated blocks,
646 * set the BH_Da_Mapped bit on them. Its important to do this
647 * under the protection of i_data_sem.
648 */
649 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
650 set_buffers_da_mapped(inode, map);
651 }
652
653 up_write((&EXT4_I(inode)->i_data_sem));
654 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
655 int ret = check_block_validity(inode, map);
656 if (ret != 0)
657 return ret;
658 }
659 return retval;
660}
661
662/* Maximum number of blocks we map for direct IO at once. */
663#define DIO_MAX_BLOCKS 4096
664
665static int _ext4_get_block(struct inode *inode, sector_t iblock,
666 struct buffer_head *bh, int flags)
667{
668 handle_t *handle = ext4_journal_current_handle();
669 struct ext4_map_blocks map;
670 int ret = 0, started = 0;
671 int dio_credits;
672
673 map.m_lblk = iblock;
674 map.m_len = bh->b_size >> inode->i_blkbits;
675
676 if (flags && !handle) {
677 /* Direct IO write... */
678 if (map.m_len > DIO_MAX_BLOCKS)
679 map.m_len = DIO_MAX_BLOCKS;
680 dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
681 handle = ext4_journal_start(inode, dio_credits);
682 if (IS_ERR(handle)) {
683 ret = PTR_ERR(handle);
684 return ret;
685 }
686 started = 1;
687 }
688
689 ret = ext4_map_blocks(handle, inode, &map, flags);
690 if (ret > 0) {
691 map_bh(bh, inode->i_sb, map.m_pblk);
692 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
693 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
694 ret = 0;
695 }
696 if (started)
697 ext4_journal_stop(handle);
698 return ret;
699}
700
701int ext4_get_block(struct inode *inode, sector_t iblock,
702 struct buffer_head *bh, int create)
703{
704 return _ext4_get_block(inode, iblock, bh,
705 create ? EXT4_GET_BLOCKS_CREATE : 0);
706}
707
708/*
709 * `handle' can be NULL if create is zero
710 */
711struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
712 ext4_lblk_t block, int create, int *errp)
713{
714 struct ext4_map_blocks map;
715 struct buffer_head *bh;
716 int fatal = 0, err;
717
718 J_ASSERT(handle != NULL || create == 0);
719
720 map.m_lblk = block;
721 map.m_len = 1;
722 err = ext4_map_blocks(handle, inode, &map,
723 create ? EXT4_GET_BLOCKS_CREATE : 0);
724
725 if (err < 0)
726 *errp = err;
727 if (err <= 0)
728 return NULL;
729 *errp = 0;
730
731 bh = sb_getblk(inode->i_sb, map.m_pblk);
732 if (!bh) {
733 *errp = -EIO;
734 return NULL;
735 }
736 if (map.m_flags & EXT4_MAP_NEW) {
737 J_ASSERT(create != 0);
738 J_ASSERT(handle != NULL);
739
740 /*
741 * Now that we do not always journal data, we should
742 * keep in mind whether this should always journal the
743 * new buffer as metadata. For now, regular file
744 * writes use ext4_get_block instead, so it's not a
745 * problem.
746 */
747 lock_buffer(bh);
748 BUFFER_TRACE(bh, "call get_create_access");
749 fatal = ext4_journal_get_create_access(handle, bh);
750 if (!fatal && !buffer_uptodate(bh)) {
751 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
752 set_buffer_uptodate(bh);
753 }
754 unlock_buffer(bh);
755 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
756 err = ext4_handle_dirty_metadata(handle, inode, bh);
757 if (!fatal)
758 fatal = err;
759 } else {
760 BUFFER_TRACE(bh, "not a new buffer");
761 }
762 if (fatal) {
763 *errp = fatal;
764 brelse(bh);
765 bh = NULL;
766 }
767 return bh;
768}
769
770struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
771 ext4_lblk_t block, int create, int *err)
772{
773 struct buffer_head *bh;
774
775 bh = ext4_getblk(handle, inode, block, create, err);
776 if (!bh)
777 return bh;
778 if (buffer_uptodate(bh))
779 return bh;
780 ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
781 wait_on_buffer(bh);
782 if (buffer_uptodate(bh))
783 return bh;
784 put_bh(bh);
785 *err = -EIO;
786 return NULL;
787}
788
789static int walk_page_buffers(handle_t *handle,
790 struct buffer_head *head,
791 unsigned from,
792 unsigned to,
793 int *partial,
794 int (*fn)(handle_t *handle,
795 struct buffer_head *bh))
796{
797 struct buffer_head *bh;
798 unsigned block_start, block_end;
799 unsigned blocksize = head->b_size;
800 int err, ret = 0;
801 struct buffer_head *next;
802
803 for (bh = head, block_start = 0;
804 ret == 0 && (bh != head || !block_start);
805 block_start = block_end, bh = next) {
806 next = bh->b_this_page;
807 block_end = block_start + blocksize;
808 if (block_end <= from || block_start >= to) {
809 if (partial && !buffer_uptodate(bh))
810 *partial = 1;
811 continue;
812 }
813 err = (*fn)(handle, bh);
814 if (!ret)
815 ret = err;
816 }
817 return ret;
818}
819
820/*
821 * To preserve ordering, it is essential that the hole instantiation and
822 * the data write be encapsulated in a single transaction. We cannot
823 * close off a transaction and start a new one between the ext4_get_block()
824 * and the commit_write(). So doing the jbd2_journal_start at the start of
825 * prepare_write() is the right place.
826 *
827 * Also, this function can nest inside ext4_writepage() ->
828 * block_write_full_page(). In that case, we *know* that ext4_writepage()
829 * has generated enough buffer credits to do the whole page. So we won't
830 * block on the journal in that case, which is good, because the caller may
831 * be PF_MEMALLOC.
832 *
833 * By accident, ext4 can be reentered when a transaction is open via
834 * quota file writes. If we were to commit the transaction while thus
835 * reentered, there can be a deadlock - we would be holding a quota
836 * lock, and the commit would never complete if another thread had a
837 * transaction open and was blocking on the quota lock - a ranking
838 * violation.
839 *
840 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
841 * will _not_ run commit under these circumstances because handle->h_ref
842 * is elevated. We'll still have enough credits for the tiny quotafile
843 * write.
844 */
845static int do_journal_get_write_access(handle_t *handle,
846 struct buffer_head *bh)
847{
848 int dirty = buffer_dirty(bh);
849 int ret;
850
851 if (!buffer_mapped(bh) || buffer_freed(bh))
852 return 0;
853 /*
854 * __block_write_begin() could have dirtied some buffers. Clean
855 * the dirty bit as jbd2_journal_get_write_access() could complain
856 * otherwise about fs integrity issues. Setting of the dirty bit
857 * by __block_write_begin() isn't a real problem here as we clear
858 * the bit before releasing a page lock and thus writeback cannot
859 * ever write the buffer.
860 */
861 if (dirty)
862 clear_buffer_dirty(bh);
863 ret = ext4_journal_get_write_access(handle, bh);
864 if (!ret && dirty)
865 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
866 return ret;
867}
868
869static int ext4_get_block_write(struct inode *inode, sector_t iblock,
870 struct buffer_head *bh_result, int create);
871static int ext4_write_begin(struct file *file, struct address_space *mapping,
872 loff_t pos, unsigned len, unsigned flags,
873 struct page **pagep, void **fsdata)
874{
875 struct inode *inode = mapping->host;
876 int ret, needed_blocks;
877 handle_t *handle;
878 int retries = 0;
879 struct page *page;
880 pgoff_t index;
881 unsigned from, to;
882
883 trace_ext4_write_begin(inode, pos, len, flags);
884 /*
885 * Reserve one block more for addition to orphan list in case
886 * we allocate blocks but write fails for some reason
887 */
888 needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
889 index = pos >> PAGE_CACHE_SHIFT;
890 from = pos & (PAGE_CACHE_SIZE - 1);
891 to = from + len;
892
893retry:
894 handle = ext4_journal_start(inode, needed_blocks);
895 if (IS_ERR(handle)) {
896 ret = PTR_ERR(handle);
897 goto out;
898 }
899
900 /* We cannot recurse into the filesystem as the transaction is already
901 * started */
902 flags |= AOP_FLAG_NOFS;
903
904 page = grab_cache_page_write_begin(mapping, index, flags);
905 if (!page) {
906 ext4_journal_stop(handle);
907 ret = -ENOMEM;
908 goto out;
909 }
910 *pagep = page;
911
912 if (ext4_should_dioread_nolock(inode))
913 ret = __block_write_begin(page, pos, len, ext4_get_block_write);
914 else
915 ret = __block_write_begin(page, pos, len, ext4_get_block);
916
917 if (!ret && ext4_should_journal_data(inode)) {
918 ret = walk_page_buffers(handle, page_buffers(page),
919 from, to, NULL, do_journal_get_write_access);
920 }
921
922 if (ret) {
923 unlock_page(page);
924 page_cache_release(page);
925 /*
926 * __block_write_begin may have instantiated a few blocks
927 * outside i_size. Trim these off again. Don't need
928 * i_size_read because we hold i_mutex.
929 *
930 * Add inode to orphan list in case we crash before
931 * truncate finishes
932 */
933 if (pos + len > inode->i_size && ext4_can_truncate(inode))
934 ext4_orphan_add(handle, inode);
935
936 ext4_journal_stop(handle);
937 if (pos + len > inode->i_size) {
938 ext4_truncate_failed_write(inode);
939 /*
940 * If truncate failed early the inode might
941 * still be on the orphan list; we need to
942 * make sure the inode is removed from the
943 * orphan list in that case.
944 */
945 if (inode->i_nlink)
946 ext4_orphan_del(NULL, inode);
947 }
948 }
949
950 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
951 goto retry;
952out:
953 return ret;
954}
955
956/* For write_end() in data=journal mode */
957static int write_end_fn(handle_t *handle, struct buffer_head *bh)
958{
959 if (!buffer_mapped(bh) || buffer_freed(bh))
960 return 0;
961 set_buffer_uptodate(bh);
962 return ext4_handle_dirty_metadata(handle, NULL, bh);
963}
964
965static int ext4_generic_write_end(struct file *file,
966 struct address_space *mapping,
967 loff_t pos, unsigned len, unsigned copied,
968 struct page *page, void *fsdata)
969{
970 int i_size_changed = 0;
971 struct inode *inode = mapping->host;
972 handle_t *handle = ext4_journal_current_handle();
973
974 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
975
976 /*
977 * No need to use i_size_read() here, the i_size
978 * cannot change under us because we hold i_mutex.
979 *
980 * But it's important to update i_size while still holding page lock:
981 * page writeout could otherwise come in and zero beyond i_size.
982 */
983 if (pos + copied > inode->i_size) {
984 i_size_write(inode, pos + copied);
985 i_size_changed = 1;
986 }
987
988 if (pos + copied > EXT4_I(inode)->i_disksize) {
989 /* We need to mark inode dirty even if
990 * new_i_size is less that inode->i_size
991 * bu greater than i_disksize.(hint delalloc)
992 */
993 ext4_update_i_disksize(inode, (pos + copied));
994 i_size_changed = 1;
995 }
996 unlock_page(page);
997 page_cache_release(page);
998
999 /*
1000 * Don't mark the inode dirty under page lock. First, it unnecessarily
1001 * makes the holding time of page lock longer. Second, it forces lock
1002 * ordering of page lock and transaction start for journaling
1003 * filesystems.
1004 */
1005 if (i_size_changed)
1006 ext4_mark_inode_dirty(handle, inode);
1007
1008 return copied;
1009}
1010
1011/*
1012 * We need to pick up the new inode size which generic_commit_write gave us
1013 * `file' can be NULL - eg, when called from page_symlink().
1014 *
1015 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1016 * buffers are managed internally.
1017 */
1018static int ext4_ordered_write_end(struct file *file,
1019 struct address_space *mapping,
1020 loff_t pos, unsigned len, unsigned copied,
1021 struct page *page, void *fsdata)
1022{
1023 handle_t *handle = ext4_journal_current_handle();
1024 struct inode *inode = mapping->host;
1025 int ret = 0, ret2;
1026
1027 trace_ext4_ordered_write_end(inode, pos, len, copied);
1028 ret = ext4_jbd2_file_inode(handle, inode);
1029
1030 if (ret == 0) {
1031 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1032 page, fsdata);
1033 copied = ret2;
1034 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1035 /* if we have allocated more blocks and copied
1036 * less. We will have blocks allocated outside
1037 * inode->i_size. So truncate them
1038 */
1039 ext4_orphan_add(handle, inode);
1040 if (ret2 < 0)
1041 ret = ret2;
1042 } else {
1043 unlock_page(page);
1044 page_cache_release(page);
1045 }
1046
1047 ret2 = ext4_journal_stop(handle);
1048 if (!ret)
1049 ret = ret2;
1050
1051 if (pos + len > inode->i_size) {
1052 ext4_truncate_failed_write(inode);
1053 /*
1054 * If truncate failed early the inode might still be
1055 * on the orphan list; we need to make sure the inode
1056 * is removed from the orphan list in that case.
1057 */
1058 if (inode->i_nlink)
1059 ext4_orphan_del(NULL, inode);
1060 }
1061
1062
1063 return ret ? ret : copied;
1064}
1065
1066static int ext4_writeback_write_end(struct file *file,
1067 struct address_space *mapping,
1068 loff_t pos, unsigned len, unsigned copied,
1069 struct page *page, void *fsdata)
1070{
1071 handle_t *handle = ext4_journal_current_handle();
1072 struct inode *inode = mapping->host;
1073 int ret = 0, ret2;
1074
1075 trace_ext4_writeback_write_end(inode, pos, len, copied);
1076 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1077 page, fsdata);
1078 copied = ret2;
1079 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1080 /* if we have allocated more blocks and copied
1081 * less. We will have blocks allocated outside
1082 * inode->i_size. So truncate them
1083 */
1084 ext4_orphan_add(handle, inode);
1085
1086 if (ret2 < 0)
1087 ret = ret2;
1088
1089 ret2 = ext4_journal_stop(handle);
1090 if (!ret)
1091 ret = ret2;
1092
1093 if (pos + len > inode->i_size) {
1094 ext4_truncate_failed_write(inode);
1095 /*
1096 * If truncate failed early the inode might still be
1097 * on the orphan list; we need to make sure the inode
1098 * is removed from the orphan list in that case.
1099 */
1100 if (inode->i_nlink)
1101 ext4_orphan_del(NULL, inode);
1102 }
1103
1104 return ret ? ret : copied;
1105}
1106
1107static int ext4_journalled_write_end(struct file *file,
1108 struct address_space *mapping,
1109 loff_t pos, unsigned len, unsigned copied,
1110 struct page *page, void *fsdata)
1111{
1112 handle_t *handle = ext4_journal_current_handle();
1113 struct inode *inode = mapping->host;
1114 int ret = 0, ret2;
1115 int partial = 0;
1116 unsigned from, to;
1117 loff_t new_i_size;
1118
1119 trace_ext4_journalled_write_end(inode, pos, len, copied);
1120 from = pos & (PAGE_CACHE_SIZE - 1);
1121 to = from + len;
1122
1123 BUG_ON(!ext4_handle_valid(handle));
1124
1125 if (copied < len) {
1126 if (!PageUptodate(page))
1127 copied = 0;
1128 page_zero_new_buffers(page, from+copied, to);
1129 }
1130
1131 ret = walk_page_buffers(handle, page_buffers(page), from,
1132 to, &partial, write_end_fn);
1133 if (!partial)
1134 SetPageUptodate(page);
1135 new_i_size = pos + copied;
1136 if (new_i_size > inode->i_size)
1137 i_size_write(inode, pos+copied);
1138 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1139 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1140 if (new_i_size > EXT4_I(inode)->i_disksize) {
1141 ext4_update_i_disksize(inode, new_i_size);
1142 ret2 = ext4_mark_inode_dirty(handle, inode);
1143 if (!ret)
1144 ret = ret2;
1145 }
1146
1147 unlock_page(page);
1148 page_cache_release(page);
1149 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1150 /* if we have allocated more blocks and copied
1151 * less. We will have blocks allocated outside
1152 * inode->i_size. So truncate them
1153 */
1154 ext4_orphan_add(handle, inode);
1155
1156 ret2 = ext4_journal_stop(handle);
1157 if (!ret)
1158 ret = ret2;
1159 if (pos + len > inode->i_size) {
1160 ext4_truncate_failed_write(inode);
1161 /*
1162 * If truncate failed early the inode might still be
1163 * on the orphan list; we need to make sure the inode
1164 * is removed from the orphan list in that case.
1165 */
1166 if (inode->i_nlink)
1167 ext4_orphan_del(NULL, inode);
1168 }
1169
1170 return ret ? ret : copied;
1171}
1172
1173/*
1174 * Reserve a single cluster located at lblock
1175 */
1176static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
1177{
1178 int retries = 0;
1179 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1180 struct ext4_inode_info *ei = EXT4_I(inode);
1181 unsigned int md_needed;
1182 int ret;
1183 ext4_lblk_t save_last_lblock;
1184 int save_len;
1185
1186 /*
1187 * We will charge metadata quota at writeout time; this saves
1188 * us from metadata over-estimation, though we may go over by
1189 * a small amount in the end. Here we just reserve for data.
1190 */
1191 ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1192 if (ret)
1193 return ret;
1194
1195 /*
1196 * recalculate the amount of metadata blocks to reserve
1197 * in order to allocate nrblocks
1198 * worse case is one extent per block
1199 */
1200repeat:
1201 spin_lock(&ei->i_block_reservation_lock);
1202 /*
1203 * ext4_calc_metadata_amount() has side effects, which we have
1204 * to be prepared undo if we fail to claim space.
1205 */
1206 save_len = ei->i_da_metadata_calc_len;
1207 save_last_lblock = ei->i_da_metadata_calc_last_lblock;
1208 md_needed = EXT4_NUM_B2C(sbi,
1209 ext4_calc_metadata_amount(inode, lblock));
1210 trace_ext4_da_reserve_space(inode, md_needed);
1211
1212 /*
1213 * We do still charge estimated metadata to the sb though;
1214 * we cannot afford to run out of free blocks.
1215 */
1216 if (ext4_claim_free_clusters(sbi, md_needed + 1, 0)) {
1217 ei->i_da_metadata_calc_len = save_len;
1218 ei->i_da_metadata_calc_last_lblock = save_last_lblock;
1219 spin_unlock(&ei->i_block_reservation_lock);
1220 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1221 yield();
1222 goto repeat;
1223 }
1224 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1225 return -ENOSPC;
1226 }
1227 ei->i_reserved_data_blocks++;
1228 ei->i_reserved_meta_blocks += md_needed;
1229 spin_unlock(&ei->i_block_reservation_lock);
1230
1231 return 0; /* success */
1232}
1233
1234static void ext4_da_release_space(struct inode *inode, int to_free)
1235{
1236 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1237 struct ext4_inode_info *ei = EXT4_I(inode);
1238
1239 if (!to_free)
1240 return; /* Nothing to release, exit */
1241
1242 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1243
1244 trace_ext4_da_release_space(inode, to_free);
1245 if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1246 /*
1247 * if there aren't enough reserved blocks, then the
1248 * counter is messed up somewhere. Since this
1249 * function is called from invalidate page, it's
1250 * harmless to return without any action.
1251 */
1252 ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: "
1253 "ino %lu, to_free %d with only %d reserved "
1254 "data blocks", inode->i_ino, to_free,
1255 ei->i_reserved_data_blocks);
1256 WARN_ON(1);
1257 to_free = ei->i_reserved_data_blocks;
1258 }
1259 ei->i_reserved_data_blocks -= to_free;
1260
1261 if (ei->i_reserved_data_blocks == 0) {
1262 /*
1263 * We can release all of the reserved metadata blocks
1264 * only when we have written all of the delayed
1265 * allocation blocks.
1266 * Note that in case of bigalloc, i_reserved_meta_blocks,
1267 * i_reserved_data_blocks, etc. refer to number of clusters.
1268 */
1269 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
1270 ei->i_reserved_meta_blocks);
1271 ei->i_reserved_meta_blocks = 0;
1272 ei->i_da_metadata_calc_len = 0;
1273 }
1274
1275 /* update fs dirty data blocks counter */
1276 percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1277
1278 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1279
1280 dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1281}
1282
1283static void ext4_da_page_release_reservation(struct page *page,
1284 unsigned long offset)
1285{
1286 int to_release = 0;
1287 struct buffer_head *head, *bh;
1288 unsigned int curr_off = 0;
1289 struct inode *inode = page->mapping->host;
1290 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1291 int num_clusters;
1292
1293 head = page_buffers(page);
1294 bh = head;
1295 do {
1296 unsigned int next_off = curr_off + bh->b_size;
1297
1298 if ((offset <= curr_off) && (buffer_delay(bh))) {
1299 to_release++;
1300 clear_buffer_delay(bh);
1301 clear_buffer_da_mapped(bh);
1302 }
1303 curr_off = next_off;
1304 } while ((bh = bh->b_this_page) != head);
1305
1306 /* If we have released all the blocks belonging to a cluster, then we
1307 * need to release the reserved space for that cluster. */
1308 num_clusters = EXT4_NUM_B2C(sbi, to_release);
1309 while (num_clusters > 0) {
1310 ext4_fsblk_t lblk;
1311 lblk = (page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits)) +
1312 ((num_clusters - 1) << sbi->s_cluster_bits);
1313 if (sbi->s_cluster_ratio == 1 ||
1314 !ext4_find_delalloc_cluster(inode, lblk, 1))
1315 ext4_da_release_space(inode, 1);
1316
1317 num_clusters--;
1318 }
1319}
1320
1321/*
1322 * Delayed allocation stuff
1323 */
1324
1325/*
1326 * mpage_da_submit_io - walks through extent of pages and try to write
1327 * them with writepage() call back
1328 *
1329 * @mpd->inode: inode
1330 * @mpd->first_page: first page of the extent
1331 * @mpd->next_page: page after the last page of the extent
1332 *
1333 * By the time mpage_da_submit_io() is called we expect all blocks
1334 * to be allocated. this may be wrong if allocation failed.
1335 *
1336 * As pages are already locked by write_cache_pages(), we can't use it
1337 */
1338static int mpage_da_submit_io(struct mpage_da_data *mpd,
1339 struct ext4_map_blocks *map)
1340{
1341 struct pagevec pvec;
1342 unsigned long index, end;
1343 int ret = 0, err, nr_pages, i;
1344 struct inode *inode = mpd->inode;
1345 struct address_space *mapping = inode->i_mapping;
1346 loff_t size = i_size_read(inode);
1347 unsigned int len, block_start;
1348 struct buffer_head *bh, *page_bufs = NULL;
1349 int journal_data = ext4_should_journal_data(inode);
1350 sector_t pblock = 0, cur_logical = 0;
1351 struct ext4_io_submit io_submit;
1352
1353 BUG_ON(mpd->next_page <= mpd->first_page);
1354 memset(&io_submit, 0, sizeof(io_submit));
1355 /*
1356 * We need to start from the first_page to the next_page - 1
1357 * to make sure we also write the mapped dirty buffer_heads.
1358 * If we look at mpd->b_blocknr we would only be looking
1359 * at the currently mapped buffer_heads.
1360 */
1361 index = mpd->first_page;
1362 end = mpd->next_page - 1;
1363
1364 pagevec_init(&pvec, 0);
1365 while (index <= end) {
1366 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1367 if (nr_pages == 0)
1368 break;
1369 for (i = 0; i < nr_pages; i++) {
1370 int commit_write = 0, skip_page = 0;
1371 struct page *page = pvec.pages[i];
1372
1373 index = page->index;
1374 if (index > end)
1375 break;
1376
1377 if (index == size >> PAGE_CACHE_SHIFT)
1378 len = size & ~PAGE_CACHE_MASK;
1379 else
1380 len = PAGE_CACHE_SIZE;
1381 if (map) {
1382 cur_logical = index << (PAGE_CACHE_SHIFT -
1383 inode->i_blkbits);
1384 pblock = map->m_pblk + (cur_logical -
1385 map->m_lblk);
1386 }
1387 index++;
1388
1389 BUG_ON(!PageLocked(page));
1390 BUG_ON(PageWriteback(page));
1391
1392 /*
1393 * If the page does not have buffers (for
1394 * whatever reason), try to create them using
1395 * __block_write_begin. If this fails,
1396 * skip the page and move on.
1397 */
1398 if (!page_has_buffers(page)) {
1399 if (__block_write_begin(page, 0, len,
1400 noalloc_get_block_write)) {
1401 skip_page:
1402 unlock_page(page);
1403 continue;
1404 }
1405 commit_write = 1;
1406 }
1407
1408 bh = page_bufs = page_buffers(page);
1409 block_start = 0;
1410 do {
1411 if (!bh)
1412 goto skip_page;
1413 if (map && (cur_logical >= map->m_lblk) &&
1414 (cur_logical <= (map->m_lblk +
1415 (map->m_len - 1)))) {
1416 if (buffer_delay(bh)) {
1417 clear_buffer_delay(bh);
1418 bh->b_blocknr = pblock;
1419 }
1420 if (buffer_da_mapped(bh))
1421 clear_buffer_da_mapped(bh);
1422 if (buffer_unwritten(bh) ||
1423 buffer_mapped(bh))
1424 BUG_ON(bh->b_blocknr != pblock);
1425 if (map->m_flags & EXT4_MAP_UNINIT)
1426 set_buffer_uninit(bh);
1427 clear_buffer_unwritten(bh);
1428 }
1429
1430 /*
1431 * skip page if block allocation undone and
1432 * block is dirty
1433 */
1434 if (ext4_bh_delay_or_unwritten(NULL, bh))
1435 skip_page = 1;
1436 bh = bh->b_this_page;
1437 block_start += bh->b_size;
1438 cur_logical++;
1439 pblock++;
1440 } while (bh != page_bufs);
1441
1442 if (skip_page)
1443 goto skip_page;
1444
1445 if (commit_write)
1446 /* mark the buffer_heads as dirty & uptodate */
1447 block_commit_write(page, 0, len);
1448
1449 clear_page_dirty_for_io(page);
1450 /*
1451 * Delalloc doesn't support data journalling,
1452 * but eventually maybe we'll lift this
1453 * restriction.
1454 */
1455 if (unlikely(journal_data && PageChecked(page)))
1456 err = __ext4_journalled_writepage(page, len);
1457 else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT))
1458 err = ext4_bio_write_page(&io_submit, page,
1459 len, mpd->wbc);
1460 else if (buffer_uninit(page_bufs)) {
1461 ext4_set_bh_endio(page_bufs, inode);
1462 err = block_write_full_page_endio(page,
1463 noalloc_get_block_write,
1464 mpd->wbc, ext4_end_io_buffer_write);
1465 } else
1466 err = block_write_full_page(page,
1467 noalloc_get_block_write, mpd->wbc);
1468
1469 if (!err)
1470 mpd->pages_written++;
1471 /*
1472 * In error case, we have to continue because
1473 * remaining pages are still locked
1474 */
1475 if (ret == 0)
1476 ret = err;
1477 }
1478 pagevec_release(&pvec);
1479 }
1480 ext4_io_submit(&io_submit);
1481 return ret;
1482}
1483
1484static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
1485{
1486 int nr_pages, i;
1487 pgoff_t index, end;
1488 struct pagevec pvec;
1489 struct inode *inode = mpd->inode;
1490 struct address_space *mapping = inode->i_mapping;
1491
1492 index = mpd->first_page;
1493 end = mpd->next_page - 1;
1494 while (index <= end) {
1495 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1496 if (nr_pages == 0)
1497 break;
1498 for (i = 0; i < nr_pages; i++) {
1499 struct page *page = pvec.pages[i];
1500 if (page->index > end)
1501 break;
1502 BUG_ON(!PageLocked(page));
1503 BUG_ON(PageWriteback(page));
1504 block_invalidatepage(page, 0);
1505 ClearPageUptodate(page);
1506 unlock_page(page);
1507 }
1508 index = pvec.pages[nr_pages - 1]->index + 1;
1509 pagevec_release(&pvec);
1510 }
1511 return;
1512}
1513
1514static void ext4_print_free_blocks(struct inode *inode)
1515{
1516 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1517 struct super_block *sb = inode->i_sb;
1518
1519 ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1520 EXT4_C2B(EXT4_SB(inode->i_sb),
1521 ext4_count_free_clusters(inode->i_sb)));
1522 ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1523 ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1524 (long long) EXT4_C2B(EXT4_SB(inode->i_sb),
1525 percpu_counter_sum(&sbi->s_freeclusters_counter)));
1526 ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1527 (long long) EXT4_C2B(EXT4_SB(inode->i_sb),
1528 percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1529 ext4_msg(sb, KERN_CRIT, "Block reservation details");
1530 ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1531 EXT4_I(inode)->i_reserved_data_blocks);
1532 ext4_msg(sb, KERN_CRIT, "i_reserved_meta_blocks=%u",
1533 EXT4_I(inode)->i_reserved_meta_blocks);
1534 return;
1535}
1536
1537/*
1538 * mpage_da_map_and_submit - go through given space, map them
1539 * if necessary, and then submit them for I/O
1540 *
1541 * @mpd - bh describing space
1542 *
1543 * The function skips space we know is already mapped to disk blocks.
1544 *
1545 */
1546static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
1547{
1548 int err, blks, get_blocks_flags;
1549 struct ext4_map_blocks map, *mapp = NULL;
1550 sector_t next = mpd->b_blocknr;
1551 unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
1552 loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
1553 handle_t *handle = NULL;
1554
1555 /*
1556 * If the blocks are mapped already, or we couldn't accumulate
1557 * any blocks, then proceed immediately to the submission stage.
1558 */
1559 if ((mpd->b_size == 0) ||
1560 ((mpd->b_state & (1 << BH_Mapped)) &&
1561 !(mpd->b_state & (1 << BH_Delay)) &&
1562 !(mpd->b_state & (1 << BH_Unwritten))))
1563 goto submit_io;
1564
1565 handle = ext4_journal_current_handle();
1566 BUG_ON(!handle);
1567
1568 /*
1569 * Call ext4_map_blocks() to allocate any delayed allocation
1570 * blocks, or to convert an uninitialized extent to be
1571 * initialized (in the case where we have written into
1572 * one or more preallocated blocks).
1573 *
1574 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
1575 * indicate that we are on the delayed allocation path. This
1576 * affects functions in many different parts of the allocation
1577 * call path. This flag exists primarily because we don't
1578 * want to change *many* call functions, so ext4_map_blocks()
1579 * will set the EXT4_STATE_DELALLOC_RESERVED flag once the
1580 * inode's allocation semaphore is taken.
1581 *
1582 * If the blocks in questions were delalloc blocks, set
1583 * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
1584 * variables are updated after the blocks have been allocated.
1585 */
1586 map.m_lblk = next;
1587 map.m_len = max_blocks;
1588 get_blocks_flags = EXT4_GET_BLOCKS_CREATE;
1589 if (ext4_should_dioread_nolock(mpd->inode))
1590 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
1591 if (mpd->b_state & (1 << BH_Delay))
1592 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
1593
1594 blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags);
1595 if (blks < 0) {
1596 struct super_block *sb = mpd->inode->i_sb;
1597
1598 err = blks;
1599 /*
1600 * If get block returns EAGAIN or ENOSPC and there
1601 * appears to be free blocks we will just let
1602 * mpage_da_submit_io() unlock all of the pages.
1603 */
1604 if (err == -EAGAIN)
1605 goto submit_io;
1606
1607 if (err == -ENOSPC && ext4_count_free_clusters(sb)) {
1608 mpd->retval = err;
1609 goto submit_io;
1610 }
1611
1612 /*
1613 * get block failure will cause us to loop in
1614 * writepages, because a_ops->writepage won't be able
1615 * to make progress. The page will be redirtied by
1616 * writepage and writepages will again try to write
1617 * the same.
1618 */
1619 if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) {
1620 ext4_msg(sb, KERN_CRIT,
1621 "delayed block allocation failed for inode %lu "
1622 "at logical offset %llu with max blocks %zd "
1623 "with error %d", mpd->inode->i_ino,
1624 (unsigned long long) next,
1625 mpd->b_size >> mpd->inode->i_blkbits, err);
1626 ext4_msg(sb, KERN_CRIT,
1627 "This should not happen!! Data will be lost\n");
1628 if (err == -ENOSPC)
1629 ext4_print_free_blocks(mpd->inode);
1630 }
1631 /* invalidate all the pages */
1632 ext4_da_block_invalidatepages(mpd);
1633
1634 /* Mark this page range as having been completed */
1635 mpd->io_done = 1;
1636 return;
1637 }
1638 BUG_ON(blks == 0);
1639
1640 mapp = ↦
1641 if (map.m_flags & EXT4_MAP_NEW) {
1642 struct block_device *bdev = mpd->inode->i_sb->s_bdev;
1643 int i;
1644
1645 for (i = 0; i < map.m_len; i++)
1646 unmap_underlying_metadata(bdev, map.m_pblk + i);
1647
1648 if (ext4_should_order_data(mpd->inode)) {
1649 err = ext4_jbd2_file_inode(handle, mpd->inode);
1650 if (err) {
1651 /* Only if the journal is aborted */
1652 mpd->retval = err;
1653 goto submit_io;
1654 }
1655 }
1656 }
1657
1658 /*
1659 * Update on-disk size along with block allocation.
1660 */
1661 disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
1662 if (disksize > i_size_read(mpd->inode))
1663 disksize = i_size_read(mpd->inode);
1664 if (disksize > EXT4_I(mpd->inode)->i_disksize) {
1665 ext4_update_i_disksize(mpd->inode, disksize);
1666 err = ext4_mark_inode_dirty(handle, mpd->inode);
1667 if (err)
1668 ext4_error(mpd->inode->i_sb,
1669 "Failed to mark inode %lu dirty",
1670 mpd->inode->i_ino);
1671 }
1672
1673submit_io:
1674 mpage_da_submit_io(mpd, mapp);
1675 mpd->io_done = 1;
1676}
1677
1678#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
1679 (1 << BH_Delay) | (1 << BH_Unwritten))
1680
1681/*
1682 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
1683 *
1684 * @mpd->lbh - extent of blocks
1685 * @logical - logical number of the block in the file
1686 * @bh - bh of the block (used to access block's state)
1687 *
1688 * the function is used to collect contig. blocks in same state
1689 */
1690static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
1691 sector_t logical, size_t b_size,
1692 unsigned long b_state)
1693{
1694 sector_t next;
1695 int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
1696
1697 /*
1698 * XXX Don't go larger than mballoc is willing to allocate
1699 * This is a stopgap solution. We eventually need to fold
1700 * mpage_da_submit_io() into this function and then call
1701 * ext4_map_blocks() multiple times in a loop
1702 */
1703 if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize)
1704 goto flush_it;
1705
1706 /* check if thereserved journal credits might overflow */
1707 if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) {
1708 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
1709 /*
1710 * With non-extent format we are limited by the journal
1711 * credit available. Total credit needed to insert
1712 * nrblocks contiguous blocks is dependent on the
1713 * nrblocks. So limit nrblocks.
1714 */
1715 goto flush_it;
1716 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
1717 EXT4_MAX_TRANS_DATA) {
1718 /*
1719 * Adding the new buffer_head would make it cross the
1720 * allowed limit for which we have journal credit
1721 * reserved. So limit the new bh->b_size
1722 */
1723 b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
1724 mpd->inode->i_blkbits;
1725 /* we will do mpage_da_submit_io in the next loop */
1726 }
1727 }
1728 /*
1729 * First block in the extent
1730 */
1731 if (mpd->b_size == 0) {
1732 mpd->b_blocknr = logical;
1733 mpd->b_size = b_size;
1734 mpd->b_state = b_state & BH_FLAGS;
1735 return;
1736 }
1737
1738 next = mpd->b_blocknr + nrblocks;
1739 /*
1740 * Can we merge the block to our big extent?
1741 */
1742 if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
1743 mpd->b_size += b_size;
1744 return;
1745 }
1746
1747flush_it:
1748 /*
1749 * We couldn't merge the block to our extent, so we
1750 * need to flush current extent and start new one
1751 */
1752 mpage_da_map_and_submit(mpd);
1753 return;
1754}
1755
1756static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1757{
1758 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1759}
1760
1761/*
1762 * This function is grabs code from the very beginning of
1763 * ext4_map_blocks, but assumes that the caller is from delayed write
1764 * time. This function looks up the requested blocks and sets the
1765 * buffer delay bit under the protection of i_data_sem.
1766 */
1767static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1768 struct ext4_map_blocks *map,
1769 struct buffer_head *bh)
1770{
1771 int retval;
1772 sector_t invalid_block = ~((sector_t) 0xffff);
1773
1774 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1775 invalid_block = ~0;
1776
1777 map->m_flags = 0;
1778 ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
1779 "logical block %lu\n", inode->i_ino, map->m_len,
1780 (unsigned long) map->m_lblk);
1781 /*
1782 * Try to see if we can get the block without requesting a new
1783 * file system block.
1784 */
1785 down_read((&EXT4_I(inode)->i_data_sem));
1786 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1787 retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1788 else
1789 retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1790
1791 if (retval == 0) {
1792 /*
1793 * XXX: __block_prepare_write() unmaps passed block,
1794 * is it OK?
1795 */
1796 /* If the block was allocated from previously allocated cluster,
1797 * then we dont need to reserve it again. */
1798 if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) {
1799 retval = ext4_da_reserve_space(inode, iblock);
1800 if (retval)
1801 /* not enough space to reserve */
1802 goto out_unlock;
1803 }
1804
1805 /* Clear EXT4_MAP_FROM_CLUSTER flag since its purpose is served
1806 * and it should not appear on the bh->b_state.
1807 */
1808 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
1809
1810 map_bh(bh, inode->i_sb, invalid_block);
1811 set_buffer_new(bh);
1812 set_buffer_delay(bh);
1813 }
1814
1815out_unlock:
1816 up_read((&EXT4_I(inode)->i_data_sem));
1817
1818 return retval;
1819}
1820
1821/*
1822 * This is a special get_blocks_t callback which is used by
1823 * ext4_da_write_begin(). It will either return mapped block or
1824 * reserve space for a single block.
1825 *
1826 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1827 * We also have b_blocknr = -1 and b_bdev initialized properly
1828 *
1829 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1830 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1831 * initialized properly.
1832 */
1833static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1834 struct buffer_head *bh, int create)
1835{
1836 struct ext4_map_blocks map;
1837 int ret = 0;
1838
1839 BUG_ON(create == 0);
1840 BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1841
1842 map.m_lblk = iblock;
1843 map.m_len = 1;
1844
1845 /*
1846 * first, we need to know whether the block is allocated already
1847 * preallocated blocks are unmapped but should treated
1848 * the same as allocated blocks.
1849 */
1850 ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1851 if (ret <= 0)
1852 return ret;
1853
1854 map_bh(bh, inode->i_sb, map.m_pblk);
1855 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
1856
1857 if (buffer_unwritten(bh)) {
1858 /* A delayed write to unwritten bh should be marked
1859 * new and mapped. Mapped ensures that we don't do
1860 * get_block multiple times when we write to the same
1861 * offset and new ensures that we do proper zero out
1862 * for partial write.
1863 */
1864 set_buffer_new(bh);
1865 set_buffer_mapped(bh);
1866 }
1867 return 0;
1868}
1869
1870/*
1871 * This function is used as a standard get_block_t calback function
1872 * when there is no desire to allocate any blocks. It is used as a
1873 * callback function for block_write_begin() and block_write_full_page().
1874 * These functions should only try to map a single block at a time.
1875 *
1876 * Since this function doesn't do block allocations even if the caller
1877 * requests it by passing in create=1, it is critically important that
1878 * any caller checks to make sure that any buffer heads are returned
1879 * by this function are either all already mapped or marked for
1880 * delayed allocation before calling block_write_full_page(). Otherwise,
1881 * b_blocknr could be left unitialized, and the page write functions will
1882 * be taken by surprise.
1883 */
1884static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
1885 struct buffer_head *bh_result, int create)
1886{
1887 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
1888 return _ext4_get_block(inode, iblock, bh_result, 0);
1889}
1890
1891static int bget_one(handle_t *handle, struct buffer_head *bh)
1892{
1893 get_bh(bh);
1894 return 0;
1895}
1896
1897static int bput_one(handle_t *handle, struct buffer_head *bh)
1898{
1899 put_bh(bh);
1900 return 0;
1901}
1902
1903static int __ext4_journalled_writepage(struct page *page,
1904 unsigned int len)
1905{
1906 struct address_space *mapping = page->mapping;
1907 struct inode *inode = mapping->host;
1908 struct buffer_head *page_bufs;
1909 handle_t *handle = NULL;
1910 int ret = 0;
1911 int err;
1912
1913 ClearPageChecked(page);
1914 page_bufs = page_buffers(page);
1915 BUG_ON(!page_bufs);
1916 walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
1917 /* As soon as we unlock the page, it can go away, but we have
1918 * references to buffers so we are safe */
1919 unlock_page(page);
1920
1921 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
1922 if (IS_ERR(handle)) {
1923 ret = PTR_ERR(handle);
1924 goto out;
1925 }
1926
1927 BUG_ON(!ext4_handle_valid(handle));
1928
1929 ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
1930 do_journal_get_write_access);
1931
1932 err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
1933 write_end_fn);
1934 if (ret == 0)
1935 ret = err;
1936 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1937 err = ext4_journal_stop(handle);
1938 if (!ret)
1939 ret = err;
1940
1941 walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
1942 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1943out:
1944 return ret;
1945}
1946
1947static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode);
1948static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate);
1949
1950/*
1951 * Note that we don't need to start a transaction unless we're journaling data
1952 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1953 * need to file the inode to the transaction's list in ordered mode because if
1954 * we are writing back data added by write(), the inode is already there and if
1955 * we are writing back data modified via mmap(), no one guarantees in which
1956 * transaction the data will hit the disk. In case we are journaling data, we
1957 * cannot start transaction directly because transaction start ranks above page
1958 * lock so we have to do some magic.
1959 *
1960 * This function can get called via...
1961 * - ext4_da_writepages after taking page lock (have journal handle)
1962 * - journal_submit_inode_data_buffers (no journal handle)
1963 * - shrink_page_list via pdflush (no journal handle)
1964 * - grab_page_cache when doing write_begin (have journal handle)
1965 *
1966 * We don't do any block allocation in this function. If we have page with
1967 * multiple blocks we need to write those buffer_heads that are mapped. This
1968 * is important for mmaped based write. So if we do with blocksize 1K
1969 * truncate(f, 1024);
1970 * a = mmap(f, 0, 4096);
1971 * a[0] = 'a';
1972 * truncate(f, 4096);
1973 * we have in the page first buffer_head mapped via page_mkwrite call back
1974 * but other buffer_heads would be unmapped but dirty (dirty done via the
1975 * do_wp_page). So writepage should write the first block. If we modify
1976 * the mmap area beyond 1024 we will again get a page_fault and the
1977 * page_mkwrite callback will do the block allocation and mark the
1978 * buffer_heads mapped.
1979 *
1980 * We redirty the page if we have any buffer_heads that is either delay or
1981 * unwritten in the page.
1982 *
1983 * We can get recursively called as show below.
1984 *
1985 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1986 * ext4_writepage()
1987 *
1988 * But since we don't do any block allocation we should not deadlock.
1989 * Page also have the dirty flag cleared so we don't get recurive page_lock.
1990 */
1991static int ext4_writepage(struct page *page,
1992 struct writeback_control *wbc)
1993{
1994 int ret = 0, commit_write = 0;
1995 loff_t size;
1996 unsigned int len;
1997 struct buffer_head *page_bufs = NULL;
1998 struct inode *inode = page->mapping->host;
1999
2000 trace_ext4_writepage(page);
2001 size = i_size_read(inode);
2002 if (page->index == size >> PAGE_CACHE_SHIFT)
2003 len = size & ~PAGE_CACHE_MASK;
2004 else
2005 len = PAGE_CACHE_SIZE;
2006
2007 /*
2008 * If the page does not have buffers (for whatever reason),
2009 * try to create them using __block_write_begin. If this
2010 * fails, redirty the page and move on.
2011 */
2012 if (!page_has_buffers(page)) {
2013 if (__block_write_begin(page, 0, len,
2014 noalloc_get_block_write)) {
2015 redirty_page:
2016 redirty_page_for_writepage(wbc, page);
2017 unlock_page(page);
2018 return 0;
2019 }
2020 commit_write = 1;
2021 }
2022 page_bufs = page_buffers(page);
2023 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2024 ext4_bh_delay_or_unwritten)) {
2025 /*
2026 * We don't want to do block allocation, so redirty
2027 * the page and return. We may reach here when we do
2028 * a journal commit via journal_submit_inode_data_buffers.
2029 * We can also reach here via shrink_page_list but it
2030 * should never be for direct reclaim so warn if that
2031 * happens
2032 */
2033 WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
2034 PF_MEMALLOC);
2035 goto redirty_page;
2036 }
2037 if (commit_write)
2038 /* now mark the buffer_heads as dirty and uptodate */
2039 block_commit_write(page, 0, len);
2040
2041 if (PageChecked(page) && ext4_should_journal_data(inode))
2042 /*
2043 * It's mmapped pagecache. Add buffers and journal it. There
2044 * doesn't seem much point in redirtying the page here.
2045 */
2046 return __ext4_journalled_writepage(page, len);
2047
2048 if (buffer_uninit(page_bufs)) {
2049 ext4_set_bh_endio(page_bufs, inode);
2050 ret = block_write_full_page_endio(page, noalloc_get_block_write,
2051 wbc, ext4_end_io_buffer_write);
2052 } else
2053 ret = block_write_full_page(page, noalloc_get_block_write,
2054 wbc);
2055
2056 return ret;
2057}
2058
2059/*
2060 * This is called via ext4_da_writepages() to
2061 * calculate the total number of credits to reserve to fit
2062 * a single extent allocation into a single transaction,
2063 * ext4_da_writpeages() will loop calling this before
2064 * the block allocation.
2065 */
2066
2067static int ext4_da_writepages_trans_blocks(struct inode *inode)
2068{
2069 int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2070
2071 /*
2072 * With non-extent format the journal credit needed to
2073 * insert nrblocks contiguous block is dependent on
2074 * number of contiguous block. So we will limit
2075 * number of contiguous block to a sane value
2076 */
2077 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
2078 (max_blocks > EXT4_MAX_TRANS_DATA))
2079 max_blocks = EXT4_MAX_TRANS_DATA;
2080
2081 return ext4_chunk_trans_blocks(inode, max_blocks);
2082}
2083
2084/*
2085 * write_cache_pages_da - walk the list of dirty pages of the given
2086 * address space and accumulate pages that need writing, and call
2087 * mpage_da_map_and_submit to map a single contiguous memory region
2088 * and then write them.
2089 */
2090static int write_cache_pages_da(struct address_space *mapping,
2091 struct writeback_control *wbc,
2092 struct mpage_da_data *mpd,
2093 pgoff_t *done_index)
2094{
2095 struct buffer_head *bh, *head;
2096 struct inode *inode = mapping->host;
2097 struct pagevec pvec;
2098 unsigned int nr_pages;
2099 sector_t logical;
2100 pgoff_t index, end;
2101 long nr_to_write = wbc->nr_to_write;
2102 int i, tag, ret = 0;
2103
2104 memset(mpd, 0, sizeof(struct mpage_da_data));
2105 mpd->wbc = wbc;
2106 mpd->inode = inode;
2107 pagevec_init(&pvec, 0);
2108 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2109 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2110
2111 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2112 tag = PAGECACHE_TAG_TOWRITE;
2113 else
2114 tag = PAGECACHE_TAG_DIRTY;
2115
2116 *done_index = index;
2117 while (index <= end) {
2118 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2119 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
2120 if (nr_pages == 0)
2121 return 0;
2122
2123 for (i = 0; i < nr_pages; i++) {
2124 struct page *page = pvec.pages[i];
2125
2126 /*
2127 * At this point, the page may be truncated or
2128 * invalidated (changing page->mapping to NULL), or
2129 * even swizzled back from swapper_space to tmpfs file
2130 * mapping. However, page->index will not change
2131 * because we have a reference on the page.
2132 */
2133 if (page->index > end)
2134 goto out;
2135
2136 *done_index = page->index + 1;
2137
2138 /*
2139 * If we can't merge this page, and we have
2140 * accumulated an contiguous region, write it
2141 */
2142 if ((mpd->next_page != page->index) &&
2143 (mpd->next_page != mpd->first_page)) {
2144 mpage_da_map_and_submit(mpd);
2145 goto ret_extent_tail;
2146 }
2147
2148 lock_page(page);
2149
2150 /*
2151 * If the page is no longer dirty, or its
2152 * mapping no longer corresponds to inode we
2153 * are writing (which means it has been
2154 * truncated or invalidated), or the page is
2155 * already under writeback and we are not
2156 * doing a data integrity writeback, skip the page
2157 */
2158 if (!PageDirty(page) ||
2159 (PageWriteback(page) &&
2160 (wbc->sync_mode == WB_SYNC_NONE)) ||
2161 unlikely(page->mapping != mapping)) {
2162 unlock_page(page);
2163 continue;
2164 }
2165
2166 wait_on_page_writeback(page);
2167 BUG_ON(PageWriteback(page));
2168
2169 if (mpd->next_page != page->index)
2170 mpd->first_page = page->index;
2171 mpd->next_page = page->index + 1;
2172 logical = (sector_t) page->index <<
2173 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2174
2175 if (!page_has_buffers(page)) {
2176 mpage_add_bh_to_extent(mpd, logical,
2177 PAGE_CACHE_SIZE,
2178 (1 << BH_Dirty) | (1 << BH_Uptodate));
2179 if (mpd->io_done)
2180 goto ret_extent_tail;
2181 } else {
2182 /*
2183 * Page with regular buffer heads,
2184 * just add all dirty ones
2185 */
2186 head = page_buffers(page);
2187 bh = head;
2188 do {
2189 BUG_ON(buffer_locked(bh));
2190 /*
2191 * We need to try to allocate
2192 * unmapped blocks in the same page.
2193 * Otherwise we won't make progress
2194 * with the page in ext4_writepage
2195 */
2196 if (ext4_bh_delay_or_unwritten(NULL, bh)) {
2197 mpage_add_bh_to_extent(mpd, logical,
2198 bh->b_size,
2199 bh->b_state);
2200 if (mpd->io_done)
2201 goto ret_extent_tail;
2202 } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2203 /*
2204 * mapped dirty buffer. We need
2205 * to update the b_state
2206 * because we look at b_state
2207 * in mpage_da_map_blocks. We
2208 * don't update b_size because
2209 * if we find an unmapped
2210 * buffer_head later we need to
2211 * use the b_state flag of that
2212 * buffer_head.
2213 */
2214 if (mpd->b_size == 0)
2215 mpd->b_state = bh->b_state & BH_FLAGS;
2216 }
2217 logical++;
2218 } while ((bh = bh->b_this_page) != head);
2219 }
2220
2221 if (nr_to_write > 0) {
2222 nr_to_write--;
2223 if (nr_to_write == 0 &&
2224 wbc->sync_mode == WB_SYNC_NONE)
2225 /*
2226 * We stop writing back only if we are
2227 * not doing integrity sync. In case of
2228 * integrity sync we have to keep going
2229 * because someone may be concurrently
2230 * dirtying pages, and we might have
2231 * synced a lot of newly appeared dirty
2232 * pages, but have not synced all of the
2233 * old dirty pages.
2234 */
2235 goto out;
2236 }
2237 }
2238 pagevec_release(&pvec);
2239 cond_resched();
2240 }
2241 return 0;
2242ret_extent_tail:
2243 ret = MPAGE_DA_EXTENT_TAIL;
2244out:
2245 pagevec_release(&pvec);
2246 cond_resched();
2247 return ret;
2248}
2249
2250
2251static int ext4_da_writepages(struct address_space *mapping,
2252 struct writeback_control *wbc)
2253{
2254 pgoff_t index;
2255 int range_whole = 0;
2256 handle_t *handle = NULL;
2257 struct mpage_da_data mpd;
2258 struct inode *inode = mapping->host;
2259 int pages_written = 0;
2260 unsigned int max_pages;
2261 int range_cyclic, cycled = 1, io_done = 0;
2262 int needed_blocks, ret = 0;
2263 long desired_nr_to_write, nr_to_writebump = 0;
2264 loff_t range_start = wbc->range_start;
2265 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2266 pgoff_t done_index = 0;
2267 pgoff_t end;
2268 struct blk_plug plug;
2269
2270 trace_ext4_da_writepages(inode, wbc);
2271
2272 /*
2273 * No pages to write? This is mainly a kludge to avoid starting
2274 * a transaction for special inodes like journal inode on last iput()
2275 * because that could violate lock ordering on umount
2276 */
2277 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2278 return 0;
2279
2280 /*
2281 * If the filesystem has aborted, it is read-only, so return
2282 * right away instead of dumping stack traces later on that
2283 * will obscure the real source of the problem. We test
2284 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2285 * the latter could be true if the filesystem is mounted
2286 * read-only, and in that case, ext4_da_writepages should
2287 * *never* be called, so if that ever happens, we would want
2288 * the stack trace.
2289 */
2290 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2291 return -EROFS;
2292
2293 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2294 range_whole = 1;
2295
2296 range_cyclic = wbc->range_cyclic;
2297 if (wbc->range_cyclic) {
2298 index = mapping->writeback_index;
2299 if (index)
2300 cycled = 0;
2301 wbc->range_start = index << PAGE_CACHE_SHIFT;
2302 wbc->range_end = LLONG_MAX;
2303 wbc->range_cyclic = 0;
2304 end = -1;
2305 } else {
2306 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2307 end = wbc->range_end >> PAGE_CACHE_SHIFT;
2308 }
2309
2310 /*
2311 * This works around two forms of stupidity. The first is in
2312 * the writeback code, which caps the maximum number of pages
2313 * written to be 1024 pages. This is wrong on multiple
2314 * levels; different architectues have a different page size,
2315 * which changes the maximum amount of data which gets
2316 * written. Secondly, 4 megabytes is way too small. XFS
2317 * forces this value to be 16 megabytes by multiplying
2318 * nr_to_write parameter by four, and then relies on its
2319 * allocator to allocate larger extents to make them
2320 * contiguous. Unfortunately this brings us to the second
2321 * stupidity, which is that ext4's mballoc code only allocates
2322 * at most 2048 blocks. So we force contiguous writes up to
2323 * the number of dirty blocks in the inode, or
2324 * sbi->max_writeback_mb_bump whichever is smaller.
2325 */
2326 max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2327 if (!range_cyclic && range_whole) {
2328 if (wbc->nr_to_write == LONG_MAX)
2329 desired_nr_to_write = wbc->nr_to_write;
2330 else
2331 desired_nr_to_write = wbc->nr_to_write * 8;
2332 } else
2333 desired_nr_to_write = ext4_num_dirty_pages(inode, index,
2334 max_pages);
2335 if (desired_nr_to_write > max_pages)
2336 desired_nr_to_write = max_pages;
2337
2338 if (wbc->nr_to_write < desired_nr_to_write) {
2339 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
2340 wbc->nr_to_write = desired_nr_to_write;
2341 }
2342
2343retry:
2344 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2345 tag_pages_for_writeback(mapping, index, end);
2346
2347 blk_start_plug(&plug);
2348 while (!ret && wbc->nr_to_write > 0) {
2349
2350 /*
2351 * we insert one extent at a time. So we need
2352 * credit needed for single extent allocation.
2353 * journalled mode is currently not supported
2354 * by delalloc
2355 */
2356 BUG_ON(ext4_should_journal_data(inode));
2357 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2358
2359 /* start a new transaction*/
2360 handle = ext4_journal_start(inode, needed_blocks);
2361 if (IS_ERR(handle)) {
2362 ret = PTR_ERR(handle);
2363 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2364 "%ld pages, ino %lu; err %d", __func__,
2365 wbc->nr_to_write, inode->i_ino, ret);
2366 blk_finish_plug(&plug);
2367 goto out_writepages;
2368 }
2369
2370 /*
2371 * Now call write_cache_pages_da() to find the next
2372 * contiguous region of logical blocks that need
2373 * blocks to be allocated by ext4 and submit them.
2374 */
2375 ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index);
2376 /*
2377 * If we have a contiguous extent of pages and we
2378 * haven't done the I/O yet, map the blocks and submit
2379 * them for I/O.
2380 */
2381 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2382 mpage_da_map_and_submit(&mpd);
2383 ret = MPAGE_DA_EXTENT_TAIL;
2384 }
2385 trace_ext4_da_write_pages(inode, &mpd);
2386 wbc->nr_to_write -= mpd.pages_written;
2387
2388 ext4_journal_stop(handle);
2389
2390 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2391 /* commit the transaction which would
2392 * free blocks released in the transaction
2393 * and try again
2394 */
2395 jbd2_journal_force_commit_nested(sbi->s_journal);
2396 ret = 0;
2397 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2398 /*
2399 * Got one extent now try with rest of the pages.
2400 * If mpd.retval is set -EIO, journal is aborted.
2401 * So we don't need to write any more.
2402 */
2403 pages_written += mpd.pages_written;
2404 ret = mpd.retval;
2405 io_done = 1;
2406 } else if (wbc->nr_to_write)
2407 /*
2408 * There is no more writeout needed
2409 * or we requested for a noblocking writeout
2410 * and we found the device congested
2411 */
2412 break;
2413 }
2414 blk_finish_plug(&plug);
2415 if (!io_done && !cycled) {
2416 cycled = 1;
2417 index = 0;
2418 wbc->range_start = index << PAGE_CACHE_SHIFT;
2419 wbc->range_end = mapping->writeback_index - 1;
2420 goto retry;
2421 }
2422
2423 /* Update index */
2424 wbc->range_cyclic = range_cyclic;
2425 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2426 /*
2427 * set the writeback_index so that range_cyclic
2428 * mode will write it back later
2429 */
2430 mapping->writeback_index = done_index;
2431
2432out_writepages:
2433 wbc->nr_to_write -= nr_to_writebump;
2434 wbc->range_start = range_start;
2435 trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
2436 return ret;
2437}
2438
2439#define FALL_BACK_TO_NONDELALLOC 1
2440static int ext4_nonda_switch(struct super_block *sb)
2441{
2442 s64 free_blocks, dirty_blocks;
2443 struct ext4_sb_info *sbi = EXT4_SB(sb);
2444
2445 /*
2446 * switch to non delalloc mode if we are running low
2447 * on free block. The free block accounting via percpu
2448 * counters can get slightly wrong with percpu_counter_batch getting
2449 * accumulated on each CPU without updating global counters
2450 * Delalloc need an accurate free block accounting. So switch
2451 * to non delalloc when we are near to error range.
2452 */
2453 free_blocks = EXT4_C2B(sbi,
2454 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
2455 dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2456 if (2 * free_blocks < 3 * dirty_blocks ||
2457 free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) {
2458 /*
2459 * free block count is less than 150% of dirty blocks
2460 * or free blocks is less than watermark
2461 */
2462 return 1;
2463 }
2464 /*
2465 * Even if we don't switch but are nearing capacity,
2466 * start pushing delalloc when 1/2 of free blocks are dirty.
2467 */
2468 if (free_blocks < 2 * dirty_blocks)
2469 writeback_inodes_sb_if_idle(sb, WB_REASON_FS_FREE_SPACE);
2470
2471 return 0;
2472}
2473
2474static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2475 loff_t pos, unsigned len, unsigned flags,
2476 struct page **pagep, void **fsdata)
2477{
2478 int ret, retries = 0;
2479 struct page *page;
2480 pgoff_t index;
2481 struct inode *inode = mapping->host;
2482 handle_t *handle;
2483
2484 index = pos >> PAGE_CACHE_SHIFT;
2485
2486 if (ext4_nonda_switch(inode->i_sb)) {
2487 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2488 return ext4_write_begin(file, mapping, pos,
2489 len, flags, pagep, fsdata);
2490 }
2491 *fsdata = (void *)0;
2492 trace_ext4_da_write_begin(inode, pos, len, flags);
2493retry:
2494 /*
2495 * With delayed allocation, we don't log the i_disksize update
2496 * if there is delayed block allocation. But we still need
2497 * to journalling the i_disksize update if writes to the end
2498 * of file which has an already mapped buffer.
2499 */
2500 handle = ext4_journal_start(inode, 1);
2501 if (IS_ERR(handle)) {
2502 ret = PTR_ERR(handle);
2503 goto out;
2504 }
2505 /* We cannot recurse into the filesystem as the transaction is already
2506 * started */
2507 flags |= AOP_FLAG_NOFS;
2508
2509 page = grab_cache_page_write_begin(mapping, index, flags);
2510 if (!page) {
2511 ext4_journal_stop(handle);
2512 ret = -ENOMEM;
2513 goto out;
2514 }
2515 *pagep = page;
2516
2517 ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2518 if (ret < 0) {
2519 unlock_page(page);
2520 ext4_journal_stop(handle);
2521 page_cache_release(page);
2522 /*
2523 * block_write_begin may have instantiated a few blocks
2524 * outside i_size. Trim these off again. Don't need
2525 * i_size_read because we hold i_mutex.
2526 */
2527 if (pos + len > inode->i_size)
2528 ext4_truncate_failed_write(inode);
2529 }
2530
2531 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2532 goto retry;
2533out:
2534 return ret;
2535}
2536
2537/*
2538 * Check if we should update i_disksize
2539 * when write to the end of file but not require block allocation
2540 */
2541static int ext4_da_should_update_i_disksize(struct page *page,
2542 unsigned long offset)
2543{
2544 struct buffer_head *bh;
2545 struct inode *inode = page->mapping->host;
2546 unsigned int idx;
2547 int i;
2548
2549 bh = page_buffers(page);
2550 idx = offset >> inode->i_blkbits;
2551
2552 for (i = 0; i < idx; i++)
2553 bh = bh->b_this_page;
2554
2555 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2556 return 0;
2557 return 1;
2558}
2559
2560static int ext4_da_write_end(struct file *file,
2561 struct address_space *mapping,
2562 loff_t pos, unsigned len, unsigned copied,
2563 struct page *page, void *fsdata)
2564{
2565 struct inode *inode = mapping->host;
2566 int ret = 0, ret2;
2567 handle_t *handle = ext4_journal_current_handle();
2568 loff_t new_i_size;
2569 unsigned long start, end;
2570 int write_mode = (int)(unsigned long)fsdata;
2571
2572 if (write_mode == FALL_BACK_TO_NONDELALLOC) {
2573 switch (ext4_inode_journal_mode(inode)) {
2574 case EXT4_INODE_ORDERED_DATA_MODE:
2575 return ext4_ordered_write_end(file, mapping, pos,
2576 len, copied, page, fsdata);
2577 case EXT4_INODE_WRITEBACK_DATA_MODE:
2578 return ext4_writeback_write_end(file, mapping, pos,
2579 len, copied, page, fsdata);
2580 default:
2581 BUG();
2582 }
2583 }
2584
2585 trace_ext4_da_write_end(inode, pos, len, copied);
2586 start = pos & (PAGE_CACHE_SIZE - 1);
2587 end = start + copied - 1;
2588
2589 /*
2590 * generic_write_end() will run mark_inode_dirty() if i_size
2591 * changes. So let's piggyback the i_disksize mark_inode_dirty
2592 * into that.
2593 */
2594
2595 new_i_size = pos + copied;
2596 if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
2597 if (ext4_da_should_update_i_disksize(page, end)) {
2598 down_write(&EXT4_I(inode)->i_data_sem);
2599 if (new_i_size > EXT4_I(inode)->i_disksize) {
2600 /*
2601 * Updating i_disksize when extending file
2602 * without needing block allocation
2603 */
2604 if (ext4_should_order_data(inode))
2605 ret = ext4_jbd2_file_inode(handle,
2606 inode);
2607
2608 EXT4_I(inode)->i_disksize = new_i_size;
2609 }
2610 up_write(&EXT4_I(inode)->i_data_sem);
2611 /* We need to mark inode dirty even if
2612 * new_i_size is less that inode->i_size
2613 * bu greater than i_disksize.(hint delalloc)
2614 */
2615 ext4_mark_inode_dirty(handle, inode);
2616 }
2617 }
2618 ret2 = generic_write_end(file, mapping, pos, len, copied,
2619 page, fsdata);
2620 copied = ret2;
2621 if (ret2 < 0)
2622 ret = ret2;
2623 ret2 = ext4_journal_stop(handle);
2624 if (!ret)
2625 ret = ret2;
2626
2627 return ret ? ret : copied;
2628}
2629
2630static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
2631{
2632 /*
2633 * Drop reserved blocks
2634 */
2635 BUG_ON(!PageLocked(page));
2636 if (!page_has_buffers(page))
2637 goto out;
2638
2639 ext4_da_page_release_reservation(page, offset);
2640
2641out:
2642 ext4_invalidatepage(page, offset);
2643
2644 return;
2645}
2646
2647/*
2648 * Force all delayed allocation blocks to be allocated for a given inode.
2649 */
2650int ext4_alloc_da_blocks(struct inode *inode)
2651{
2652 trace_ext4_alloc_da_blocks(inode);
2653
2654 if (!EXT4_I(inode)->i_reserved_data_blocks &&
2655 !EXT4_I(inode)->i_reserved_meta_blocks)
2656 return 0;
2657
2658 /*
2659 * We do something simple for now. The filemap_flush() will
2660 * also start triggering a write of the data blocks, which is
2661 * not strictly speaking necessary (and for users of
2662 * laptop_mode, not even desirable). However, to do otherwise
2663 * would require replicating code paths in:
2664 *
2665 * ext4_da_writepages() ->
2666 * write_cache_pages() ---> (via passed in callback function)
2667 * __mpage_da_writepage() -->
2668 * mpage_add_bh_to_extent()
2669 * mpage_da_map_blocks()
2670 *
2671 * The problem is that write_cache_pages(), located in
2672 * mm/page-writeback.c, marks pages clean in preparation for
2673 * doing I/O, which is not desirable if we're not planning on
2674 * doing I/O at all.
2675 *
2676 * We could call write_cache_pages(), and then redirty all of
2677 * the pages by calling redirty_page_for_writepage() but that
2678 * would be ugly in the extreme. So instead we would need to
2679 * replicate parts of the code in the above functions,
2680 * simplifying them because we wouldn't actually intend to
2681 * write out the pages, but rather only collect contiguous
2682 * logical block extents, call the multi-block allocator, and
2683 * then update the buffer heads with the block allocations.
2684 *
2685 * For now, though, we'll cheat by calling filemap_flush(),
2686 * which will map the blocks, and start the I/O, but not
2687 * actually wait for the I/O to complete.
2688 */
2689 return filemap_flush(inode->i_mapping);
2690}
2691
2692/*
2693 * bmap() is special. It gets used by applications such as lilo and by
2694 * the swapper to find the on-disk block of a specific piece of data.
2695 *
2696 * Naturally, this is dangerous if the block concerned is still in the
2697 * journal. If somebody makes a swapfile on an ext4 data-journaling
2698 * filesystem and enables swap, then they may get a nasty shock when the
2699 * data getting swapped to that swapfile suddenly gets overwritten by
2700 * the original zero's written out previously to the journal and
2701 * awaiting writeback in the kernel's buffer cache.
2702 *
2703 * So, if we see any bmap calls here on a modified, data-journaled file,
2704 * take extra steps to flush any blocks which might be in the cache.
2705 */
2706static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2707{
2708 struct inode *inode = mapping->host;
2709 journal_t *journal;
2710 int err;
2711
2712 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
2713 test_opt(inode->i_sb, DELALLOC)) {
2714 /*
2715 * With delalloc we want to sync the file
2716 * so that we can make sure we allocate
2717 * blocks for file
2718 */
2719 filemap_write_and_wait(mapping);
2720 }
2721
2722 if (EXT4_JOURNAL(inode) &&
2723 ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
2724 /*
2725 * This is a REALLY heavyweight approach, but the use of
2726 * bmap on dirty files is expected to be extremely rare:
2727 * only if we run lilo or swapon on a freshly made file
2728 * do we expect this to happen.
2729 *
2730 * (bmap requires CAP_SYS_RAWIO so this does not
2731 * represent an unprivileged user DOS attack --- we'd be
2732 * in trouble if mortal users could trigger this path at
2733 * will.)
2734 *
2735 * NB. EXT4_STATE_JDATA is not set on files other than
2736 * regular files. If somebody wants to bmap a directory
2737 * or symlink and gets confused because the buffer
2738 * hasn't yet been flushed to disk, they deserve
2739 * everything they get.
2740 */
2741
2742 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
2743 journal = EXT4_JOURNAL(inode);
2744 jbd2_journal_lock_updates(journal);
2745 err = jbd2_journal_flush(journal);
2746 jbd2_journal_unlock_updates(journal);
2747
2748 if (err)
2749 return 0;
2750 }
2751
2752 return generic_block_bmap(mapping, block, ext4_get_block);
2753}
2754
2755static int ext4_readpage(struct file *file, struct page *page)
2756{
2757 trace_ext4_readpage(page);
2758 return mpage_readpage(page, ext4_get_block);
2759}
2760
2761static int
2762ext4_readpages(struct file *file, struct address_space *mapping,
2763 struct list_head *pages, unsigned nr_pages)
2764{
2765 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
2766}
2767
2768static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
2769{
2770 struct buffer_head *head, *bh;
2771 unsigned int curr_off = 0;
2772
2773 if (!page_has_buffers(page))
2774 return;
2775 head = bh = page_buffers(page);
2776 do {
2777 if (offset <= curr_off && test_clear_buffer_uninit(bh)
2778 && bh->b_private) {
2779 ext4_free_io_end(bh->b_private);
2780 bh->b_private = NULL;
2781 bh->b_end_io = NULL;
2782 }
2783 curr_off = curr_off + bh->b_size;
2784 bh = bh->b_this_page;
2785 } while (bh != head);
2786}
2787
2788static void ext4_invalidatepage(struct page *page, unsigned long offset)
2789{
2790 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2791
2792 trace_ext4_invalidatepage(page, offset);
2793
2794 /*
2795 * free any io_end structure allocated for buffers to be discarded
2796 */
2797 if (ext4_should_dioread_nolock(page->mapping->host))
2798 ext4_invalidatepage_free_endio(page, offset);
2799 /*
2800 * If it's a full truncate we just forget about the pending dirtying
2801 */
2802 if (offset == 0)
2803 ClearPageChecked(page);
2804
2805 if (journal)
2806 jbd2_journal_invalidatepage(journal, page, offset);
2807 else
2808 block_invalidatepage(page, offset);
2809}
2810
2811static int ext4_releasepage(struct page *page, gfp_t wait)
2812{
2813 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2814
2815 trace_ext4_releasepage(page);
2816
2817 WARN_ON(PageChecked(page));
2818 if (!page_has_buffers(page))
2819 return 0;
2820 if (journal)
2821 return jbd2_journal_try_to_free_buffers(journal, page, wait);
2822 else
2823 return try_to_free_buffers(page);
2824}
2825
2826/*
2827 * ext4_get_block used when preparing for a DIO write or buffer write.
2828 * We allocate an uinitialized extent if blocks haven't been allocated.
2829 * The extent will be converted to initialized after the IO is complete.
2830 */
2831static int ext4_get_block_write(struct inode *inode, sector_t iblock,
2832 struct buffer_head *bh_result, int create)
2833{
2834 ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
2835 inode->i_ino, create);
2836 return _ext4_get_block(inode, iblock, bh_result,
2837 EXT4_GET_BLOCKS_IO_CREATE_EXT);
2838}
2839
2840static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
2841 ssize_t size, void *private, int ret,
2842 bool is_async)
2843{
2844 struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
2845 ext4_io_end_t *io_end = iocb->private;
2846 struct workqueue_struct *wq;
2847 unsigned long flags;
2848 struct ext4_inode_info *ei;
2849
2850 /* if not async direct IO or dio with 0 bytes write, just return */
2851 if (!io_end || !size)
2852 goto out;
2853
2854 ext_debug("ext4_end_io_dio(): io_end 0x%p "
2855 "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
2856 iocb->private, io_end->inode->i_ino, iocb, offset,
2857 size);
2858
2859 iocb->private = NULL;
2860
2861 /* if not aio dio with unwritten extents, just free io and return */
2862 if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
2863 ext4_free_io_end(io_end);
2864out:
2865 if (is_async)
2866 aio_complete(iocb, ret, 0);
2867 inode_dio_done(inode);
2868 return;
2869 }
2870
2871 io_end->offset = offset;
2872 io_end->size = size;
2873 if (is_async) {
2874 io_end->iocb = iocb;
2875 io_end->result = ret;
2876 }
2877 wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
2878
2879 /* Add the io_end to per-inode completed aio dio list*/
2880 ei = EXT4_I(io_end->inode);
2881 spin_lock_irqsave(&ei->i_completed_io_lock, flags);
2882 list_add_tail(&io_end->list, &ei->i_completed_io_list);
2883 spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
2884
2885 /* queue the work to convert unwritten extents to written */
2886 queue_work(wq, &io_end->work);
2887}
2888
2889static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
2890{
2891 ext4_io_end_t *io_end = bh->b_private;
2892 struct workqueue_struct *wq;
2893 struct inode *inode;
2894 unsigned long flags;
2895
2896 if (!test_clear_buffer_uninit(bh) || !io_end)
2897 goto out;
2898
2899 if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) {
2900 ext4_msg(io_end->inode->i_sb, KERN_INFO,
2901 "sb umounted, discard end_io request for inode %lu",
2902 io_end->inode->i_ino);
2903 ext4_free_io_end(io_end);
2904 goto out;
2905 }
2906
2907 /*
2908 * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now,
2909 * but being more careful is always safe for the future change.
2910 */
2911 inode = io_end->inode;
2912 ext4_set_io_unwritten_flag(inode, io_end);
2913
2914 /* Add the io_end to per-inode completed io list*/
2915 spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
2916 list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list);
2917 spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
2918
2919 wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq;
2920 /* queue the work to convert unwritten extents to written */
2921 queue_work(wq, &io_end->work);
2922out:
2923 bh->b_private = NULL;
2924 bh->b_end_io = NULL;
2925 clear_buffer_uninit(bh);
2926 end_buffer_async_write(bh, uptodate);
2927}
2928
2929static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
2930{
2931 ext4_io_end_t *io_end;
2932 struct page *page = bh->b_page;
2933 loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT;
2934 size_t size = bh->b_size;
2935
2936retry:
2937 io_end = ext4_init_io_end(inode, GFP_ATOMIC);
2938 if (!io_end) {
2939 pr_warn_ratelimited("%s: allocation fail\n", __func__);
2940 schedule();
2941 goto retry;
2942 }
2943 io_end->offset = offset;
2944 io_end->size = size;
2945 /*
2946 * We need to hold a reference to the page to make sure it
2947 * doesn't get evicted before ext4_end_io_work() has a chance
2948 * to convert the extent from written to unwritten.
2949 */
2950 io_end->page = page;
2951 get_page(io_end->page);
2952
2953 bh->b_private = io_end;
2954 bh->b_end_io = ext4_end_io_buffer_write;
2955 return 0;
2956}
2957
2958/*
2959 * For ext4 extent files, ext4 will do direct-io write to holes,
2960 * preallocated extents, and those write extend the file, no need to
2961 * fall back to buffered IO.
2962 *
2963 * For holes, we fallocate those blocks, mark them as uninitialized
2964 * If those blocks were preallocated, we mark sure they are splited, but
2965 * still keep the range to write as uninitialized.
2966 *
2967 * The unwrritten extents will be converted to written when DIO is completed.
2968 * For async direct IO, since the IO may still pending when return, we
2969 * set up an end_io call back function, which will do the conversion
2970 * when async direct IO completed.
2971 *
2972 * If the O_DIRECT write will extend the file then add this inode to the
2973 * orphan list. So recovery will truncate it back to the original size
2974 * if the machine crashes during the write.
2975 *
2976 */
2977static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
2978 const struct iovec *iov, loff_t offset,
2979 unsigned long nr_segs)
2980{
2981 struct file *file = iocb->ki_filp;
2982 struct inode *inode = file->f_mapping->host;
2983 ssize_t ret;
2984 size_t count = iov_length(iov, nr_segs);
2985
2986 loff_t final_size = offset + count;
2987 if (rw == WRITE && final_size <= inode->i_size) {
2988 /*
2989 * We could direct write to holes and fallocate.
2990 *
2991 * Allocated blocks to fill the hole are marked as uninitialized
2992 * to prevent parallel buffered read to expose the stale data
2993 * before DIO complete the data IO.
2994 *
2995 * As to previously fallocated extents, ext4 get_block
2996 * will just simply mark the buffer mapped but still
2997 * keep the extents uninitialized.
2998 *
2999 * for non AIO case, we will convert those unwritten extents
3000 * to written after return back from blockdev_direct_IO.
3001 *
3002 * for async DIO, the conversion needs to be defered when
3003 * the IO is completed. The ext4 end_io callback function
3004 * will be called to take care of the conversion work.
3005 * Here for async case, we allocate an io_end structure to
3006 * hook to the iocb.
3007 */
3008 iocb->private = NULL;
3009 EXT4_I(inode)->cur_aio_dio = NULL;
3010 if (!is_sync_kiocb(iocb)) {
3011 ext4_io_end_t *io_end =
3012 ext4_init_io_end(inode, GFP_NOFS);
3013 if (!io_end)
3014 return -ENOMEM;
3015 io_end->flag |= EXT4_IO_END_DIRECT;
3016 iocb->private = io_end;
3017 /*
3018 * we save the io structure for current async
3019 * direct IO, so that later ext4_map_blocks()
3020 * could flag the io structure whether there
3021 * is a unwritten extents needs to be converted
3022 * when IO is completed.
3023 */
3024 EXT4_I(inode)->cur_aio_dio = iocb->private;
3025 }
3026
3027 ret = __blockdev_direct_IO(rw, iocb, inode,
3028 inode->i_sb->s_bdev, iov,
3029 offset, nr_segs,
3030 ext4_get_block_write,
3031 ext4_end_io_dio,
3032 NULL,
3033 DIO_LOCKING);
3034 if (iocb->private)
3035 EXT4_I(inode)->cur_aio_dio = NULL;
3036 /*
3037 * The io_end structure takes a reference to the inode,
3038 * that structure needs to be destroyed and the
3039 * reference to the inode need to be dropped, when IO is
3040 * complete, even with 0 byte write, or failed.
3041 *
3042 * In the successful AIO DIO case, the io_end structure will be
3043 * desctroyed and the reference to the inode will be dropped
3044 * after the end_io call back function is called.
3045 *
3046 * In the case there is 0 byte write, or error case, since
3047 * VFS direct IO won't invoke the end_io call back function,
3048 * we need to free the end_io structure here.
3049 */
3050 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
3051 ext4_free_io_end(iocb->private);
3052 iocb->private = NULL;
3053 } else if (ret > 0 && ext4_test_inode_state(inode,
3054 EXT4_STATE_DIO_UNWRITTEN)) {
3055 int err;
3056 /*
3057 * for non AIO case, since the IO is already
3058 * completed, we could do the conversion right here
3059 */
3060 err = ext4_convert_unwritten_extents(inode,
3061 offset, ret);
3062 if (err < 0)
3063 ret = err;
3064 ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3065 }
3066 return ret;
3067 }
3068
3069 /* for write the the end of file case, we fall back to old way */
3070 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3071}
3072
3073static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3074 const struct iovec *iov, loff_t offset,
3075 unsigned long nr_segs)
3076{
3077 struct file *file = iocb->ki_filp;
3078 struct inode *inode = file->f_mapping->host;
3079 ssize_t ret;
3080
3081 /*
3082 * If we are doing data journalling we don't support O_DIRECT
3083 */
3084 if (ext4_should_journal_data(inode))
3085 return 0;
3086
3087 trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
3088 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3089 ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3090 else
3091 ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3092 trace_ext4_direct_IO_exit(inode, offset,
3093 iov_length(iov, nr_segs), rw, ret);
3094 return ret;
3095}
3096
3097/*
3098 * Pages can be marked dirty completely asynchronously from ext4's journalling
3099 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3100 * much here because ->set_page_dirty is called under VFS locks. The page is
3101 * not necessarily locked.
3102 *
3103 * We cannot just dirty the page and leave attached buffers clean, because the
3104 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3105 * or jbddirty because all the journalling code will explode.
3106 *
3107 * So what we do is to mark the page "pending dirty" and next time writepage
3108 * is called, propagate that into the buffers appropriately.
3109 */
3110static int ext4_journalled_set_page_dirty(struct page *page)
3111{
3112 SetPageChecked(page);
3113 return __set_page_dirty_nobuffers(page);
3114}
3115
3116static const struct address_space_operations ext4_ordered_aops = {
3117 .readpage = ext4_readpage,
3118 .readpages = ext4_readpages,
3119 .writepage = ext4_writepage,
3120 .write_begin = ext4_write_begin,
3121 .write_end = ext4_ordered_write_end,
3122 .bmap = ext4_bmap,
3123 .invalidatepage = ext4_invalidatepage,
3124 .releasepage = ext4_releasepage,
3125 .direct_IO = ext4_direct_IO,
3126 .migratepage = buffer_migrate_page,
3127 .is_partially_uptodate = block_is_partially_uptodate,
3128 .error_remove_page = generic_error_remove_page,
3129};
3130
3131static const struct address_space_operations ext4_writeback_aops = {
3132 .readpage = ext4_readpage,
3133 .readpages = ext4_readpages,
3134 .writepage = ext4_writepage,
3135 .write_begin = ext4_write_begin,
3136 .write_end = ext4_writeback_write_end,
3137 .bmap = ext4_bmap,
3138 .invalidatepage = ext4_invalidatepage,
3139 .releasepage = ext4_releasepage,
3140 .direct_IO = ext4_direct_IO,
3141 .migratepage = buffer_migrate_page,
3142 .is_partially_uptodate = block_is_partially_uptodate,
3143 .error_remove_page = generic_error_remove_page,
3144};
3145
3146static const struct address_space_operations ext4_journalled_aops = {
3147 .readpage = ext4_readpage,
3148 .readpages = ext4_readpages,
3149 .writepage = ext4_writepage,
3150 .write_begin = ext4_write_begin,
3151 .write_end = ext4_journalled_write_end,
3152 .set_page_dirty = ext4_journalled_set_page_dirty,
3153 .bmap = ext4_bmap,
3154 .invalidatepage = ext4_invalidatepage,
3155 .releasepage = ext4_releasepage,
3156 .direct_IO = ext4_direct_IO,
3157 .is_partially_uptodate = block_is_partially_uptodate,
3158 .error_remove_page = generic_error_remove_page,
3159};
3160
3161static const struct address_space_operations ext4_da_aops = {
3162 .readpage = ext4_readpage,
3163 .readpages = ext4_readpages,
3164 .writepage = ext4_writepage,
3165 .writepages = ext4_da_writepages,
3166 .write_begin = ext4_da_write_begin,
3167 .write_end = ext4_da_write_end,
3168 .bmap = ext4_bmap,
3169 .invalidatepage = ext4_da_invalidatepage,
3170 .releasepage = ext4_releasepage,
3171 .direct_IO = ext4_direct_IO,
3172 .migratepage = buffer_migrate_page,
3173 .is_partially_uptodate = block_is_partially_uptodate,
3174 .error_remove_page = generic_error_remove_page,
3175};
3176
3177void ext4_set_aops(struct inode *inode)
3178{
3179 switch (ext4_inode_journal_mode(inode)) {
3180 case EXT4_INODE_ORDERED_DATA_MODE:
3181 if (test_opt(inode->i_sb, DELALLOC))
3182 inode->i_mapping->a_ops = &ext4_da_aops;
3183 else
3184 inode->i_mapping->a_ops = &ext4_ordered_aops;
3185 break;
3186 case EXT4_INODE_WRITEBACK_DATA_MODE:
3187 if (test_opt(inode->i_sb, DELALLOC))
3188 inode->i_mapping->a_ops = &ext4_da_aops;
3189 else
3190 inode->i_mapping->a_ops = &ext4_writeback_aops;
3191 break;
3192 case EXT4_INODE_JOURNAL_DATA_MODE:
3193 inode->i_mapping->a_ops = &ext4_journalled_aops;
3194 break;
3195 default:
3196 BUG();
3197 }
3198}
3199
3200
3201/*
3202 * ext4_discard_partial_page_buffers()
3203 * Wrapper function for ext4_discard_partial_page_buffers_no_lock.
3204 * This function finds and locks the page containing the offset
3205 * "from" and passes it to ext4_discard_partial_page_buffers_no_lock.
3206 * Calling functions that already have the page locked should call
3207 * ext4_discard_partial_page_buffers_no_lock directly.
3208 */
3209int ext4_discard_partial_page_buffers(handle_t *handle,
3210 struct address_space *mapping, loff_t from,
3211 loff_t length, int flags)
3212{
3213 struct inode *inode = mapping->host;
3214 struct page *page;
3215 int err = 0;
3216
3217 page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3218 mapping_gfp_mask(mapping) & ~__GFP_FS);
3219 if (!page)
3220 return -ENOMEM;
3221
3222 err = ext4_discard_partial_page_buffers_no_lock(handle, inode, page,
3223 from, length, flags);
3224
3225 unlock_page(page);
3226 page_cache_release(page);
3227 return err;
3228}
3229
3230/*
3231 * ext4_discard_partial_page_buffers_no_lock()
3232 * Zeros a page range of length 'length' starting from offset 'from'.
3233 * Buffer heads that correspond to the block aligned regions of the
3234 * zeroed range will be unmapped. Unblock aligned regions
3235 * will have the corresponding buffer head mapped if needed so that
3236 * that region of the page can be updated with the partial zero out.
3237 *
3238 * This function assumes that the page has already been locked. The
3239 * The range to be discarded must be contained with in the given page.
3240 * If the specified range exceeds the end of the page it will be shortened
3241 * to the end of the page that corresponds to 'from'. This function is
3242 * appropriate for updating a page and it buffer heads to be unmapped and
3243 * zeroed for blocks that have been either released, or are going to be
3244 * released.
3245 *
3246 * handle: The journal handle
3247 * inode: The files inode
3248 * page: A locked page that contains the offset "from"
3249 * from: The starting byte offset (from the begining of the file)
3250 * to begin discarding
3251 * len: The length of bytes to discard
3252 * flags: Optional flags that may be used:
3253 *
3254 * EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED
3255 * Only zero the regions of the page whose buffer heads
3256 * have already been unmapped. This flag is appropriate
3257 * for updateing the contents of a page whose blocks may
3258 * have already been released, and we only want to zero
3259 * out the regions that correspond to those released blocks.
3260 *
3261 * Returns zero on sucess or negative on failure.
3262 */
3263static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
3264 struct inode *inode, struct page *page, loff_t from,
3265 loff_t length, int flags)
3266{
3267 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3268 unsigned int offset = from & (PAGE_CACHE_SIZE-1);
3269 unsigned int blocksize, max, pos;
3270 ext4_lblk_t iblock;
3271 struct buffer_head *bh;
3272 int err = 0;
3273
3274 blocksize = inode->i_sb->s_blocksize;
3275 max = PAGE_CACHE_SIZE - offset;
3276
3277 if (index != page->index)
3278 return -EINVAL;
3279
3280 /*
3281 * correct length if it does not fall between
3282 * 'from' and the end of the page
3283 */
3284 if (length > max || length < 0)
3285 length = max;
3286
3287 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3288
3289 if (!page_has_buffers(page))
3290 create_empty_buffers(page, blocksize, 0);
3291
3292 /* Find the buffer that contains "offset" */
3293 bh = page_buffers(page);
3294 pos = blocksize;
3295 while (offset >= pos) {
3296 bh = bh->b_this_page;
3297 iblock++;
3298 pos += blocksize;
3299 }
3300
3301 pos = offset;
3302 while (pos < offset + length) {
3303 unsigned int end_of_block, range_to_discard;
3304
3305 err = 0;
3306
3307 /* The length of space left to zero and unmap */
3308 range_to_discard = offset + length - pos;
3309
3310 /* The length of space until the end of the block */
3311 end_of_block = blocksize - (pos & (blocksize-1));
3312
3313 /*
3314 * Do not unmap or zero past end of block
3315 * for this buffer head
3316 */
3317 if (range_to_discard > end_of_block)
3318 range_to_discard = end_of_block;
3319
3320
3321 /*
3322 * Skip this buffer head if we are only zeroing unampped
3323 * regions of the page
3324 */
3325 if (flags & EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED &&
3326 buffer_mapped(bh))
3327 goto next;
3328
3329 /* If the range is block aligned, unmap */
3330 if (range_to_discard == blocksize) {
3331 clear_buffer_dirty(bh);
3332 bh->b_bdev = NULL;
3333 clear_buffer_mapped(bh);
3334 clear_buffer_req(bh);
3335 clear_buffer_new(bh);
3336 clear_buffer_delay(bh);
3337 clear_buffer_unwritten(bh);
3338 clear_buffer_uptodate(bh);
3339 zero_user(page, pos, range_to_discard);
3340 BUFFER_TRACE(bh, "Buffer discarded");
3341 goto next;
3342 }
3343
3344 /*
3345 * If this block is not completely contained in the range
3346 * to be discarded, then it is not going to be released. Because
3347 * we need to keep this block, we need to make sure this part
3348 * of the page is uptodate before we modify it by writeing
3349 * partial zeros on it.
3350 */
3351 if (!buffer_mapped(bh)) {
3352 /*
3353 * Buffer head must be mapped before we can read
3354 * from the block
3355 */
3356 BUFFER_TRACE(bh, "unmapped");
3357 ext4_get_block(inode, iblock, bh, 0);
3358 /* unmapped? It's a hole - nothing to do */
3359 if (!buffer_mapped(bh)) {
3360 BUFFER_TRACE(bh, "still unmapped");
3361 goto next;
3362 }
3363 }
3364
3365 /* Ok, it's mapped. Make sure it's up-to-date */
3366 if (PageUptodate(page))
3367 set_buffer_uptodate(bh);
3368
3369 if (!buffer_uptodate(bh)) {
3370 err = -EIO;
3371 ll_rw_block(READ, 1, &bh);
3372 wait_on_buffer(bh);
3373 /* Uhhuh. Read error. Complain and punt.*/
3374 if (!buffer_uptodate(bh))
3375 goto next;
3376 }
3377
3378 if (ext4_should_journal_data(inode)) {
3379 BUFFER_TRACE(bh, "get write access");
3380 err = ext4_journal_get_write_access(handle, bh);
3381 if (err)
3382 goto next;
3383 }
3384
3385 zero_user(page, pos, range_to_discard);
3386
3387 err = 0;
3388 if (ext4_should_journal_data(inode)) {
3389 err = ext4_handle_dirty_metadata(handle, inode, bh);
3390 } else
3391 mark_buffer_dirty(bh);
3392
3393 BUFFER_TRACE(bh, "Partial buffer zeroed");
3394next:
3395 bh = bh->b_this_page;
3396 iblock++;
3397 pos += range_to_discard;
3398 }
3399
3400 return err;
3401}
3402
3403int ext4_can_truncate(struct inode *inode)
3404{
3405 if (S_ISREG(inode->i_mode))
3406 return 1;
3407 if (S_ISDIR(inode->i_mode))
3408 return 1;
3409 if (S_ISLNK(inode->i_mode))
3410 return !ext4_inode_is_fast_symlink(inode);
3411 return 0;
3412}
3413
3414/*
3415 * ext4_punch_hole: punches a hole in a file by releaseing the blocks
3416 * associated with the given offset and length
3417 *
3418 * @inode: File inode
3419 * @offset: The offset where the hole will begin
3420 * @len: The length of the hole
3421 *
3422 * Returns: 0 on sucess or negative on failure
3423 */
3424
3425int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
3426{
3427 struct inode *inode = file->f_path.dentry->d_inode;
3428 if (!S_ISREG(inode->i_mode))
3429 return -EOPNOTSUPP;
3430
3431 if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
3432 /* TODO: Add support for non extent hole punching */
3433 return -EOPNOTSUPP;
3434 }
3435
3436 if (EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) {
3437 /* TODO: Add support for bigalloc file systems */
3438 return -EOPNOTSUPP;
3439 }
3440
3441 return ext4_ext_punch_hole(file, offset, length);
3442}
3443
3444/*
3445 * ext4_truncate()
3446 *
3447 * We block out ext4_get_block() block instantiations across the entire
3448 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3449 * simultaneously on behalf of the same inode.
3450 *
3451 * As we work through the truncate and commit bits of it to the journal there
3452 * is one core, guiding principle: the file's tree must always be consistent on
3453 * disk. We must be able to restart the truncate after a crash.
3454 *
3455 * The file's tree may be transiently inconsistent in memory (although it
3456 * probably isn't), but whenever we close off and commit a journal transaction,
3457 * the contents of (the filesystem + the journal) must be consistent and
3458 * restartable. It's pretty simple, really: bottom up, right to left (although
3459 * left-to-right works OK too).
3460 *
3461 * Note that at recovery time, journal replay occurs *before* the restart of
3462 * truncate against the orphan inode list.
3463 *
3464 * The committed inode has the new, desired i_size (which is the same as
3465 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
3466 * that this inode's truncate did not complete and it will again call
3467 * ext4_truncate() to have another go. So there will be instantiated blocks
3468 * to the right of the truncation point in a crashed ext4 filesystem. But
3469 * that's fine - as long as they are linked from the inode, the post-crash
3470 * ext4_truncate() run will find them and release them.
3471 */
3472void ext4_truncate(struct inode *inode)
3473{
3474 trace_ext4_truncate_enter(inode);
3475
3476 if (!ext4_can_truncate(inode))
3477 return;
3478
3479 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3480
3481 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
3482 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
3483
3484 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3485 ext4_ext_truncate(inode);
3486 else
3487 ext4_ind_truncate(inode);
3488
3489 trace_ext4_truncate_exit(inode);
3490}
3491
3492/*
3493 * ext4_get_inode_loc returns with an extra refcount against the inode's
3494 * underlying buffer_head on success. If 'in_mem' is true, we have all
3495 * data in memory that is needed to recreate the on-disk version of this
3496 * inode.
3497 */
3498static int __ext4_get_inode_loc(struct inode *inode,
3499 struct ext4_iloc *iloc, int in_mem)
3500{
3501 struct ext4_group_desc *gdp;
3502 struct buffer_head *bh;
3503 struct super_block *sb = inode->i_sb;
3504 ext4_fsblk_t block;
3505 int inodes_per_block, inode_offset;
3506
3507 iloc->bh = NULL;
3508 if (!ext4_valid_inum(sb, inode->i_ino))
3509 return -EIO;
3510
3511 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
3512 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
3513 if (!gdp)
3514 return -EIO;
3515
3516 /*
3517 * Figure out the offset within the block group inode table
3518 */
3519 inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
3520 inode_offset = ((inode->i_ino - 1) %
3521 EXT4_INODES_PER_GROUP(sb));
3522 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
3523 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
3524
3525 bh = sb_getblk(sb, block);
3526 if (!bh) {
3527 EXT4_ERROR_INODE_BLOCK(inode, block,
3528 "unable to read itable block");
3529 return -EIO;
3530 }
3531 if (!buffer_uptodate(bh)) {
3532 lock_buffer(bh);
3533
3534 /*
3535 * If the buffer has the write error flag, we have failed
3536 * to write out another inode in the same block. In this
3537 * case, we don't have to read the block because we may
3538 * read the old inode data successfully.
3539 */
3540 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
3541 set_buffer_uptodate(bh);
3542
3543 if (buffer_uptodate(bh)) {
3544 /* someone brought it uptodate while we waited */
3545 unlock_buffer(bh);
3546 goto has_buffer;
3547 }
3548
3549 /*
3550 * If we have all information of the inode in memory and this
3551 * is the only valid inode in the block, we need not read the
3552 * block.
3553 */
3554 if (in_mem) {
3555 struct buffer_head *bitmap_bh;
3556 int i, start;
3557
3558 start = inode_offset & ~(inodes_per_block - 1);
3559
3560 /* Is the inode bitmap in cache? */
3561 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
3562 if (!bitmap_bh)
3563 goto make_io;
3564
3565 /*
3566 * If the inode bitmap isn't in cache then the
3567 * optimisation may end up performing two reads instead
3568 * of one, so skip it.
3569 */
3570 if (!buffer_uptodate(bitmap_bh)) {
3571 brelse(bitmap_bh);
3572 goto make_io;
3573 }
3574 for (i = start; i < start + inodes_per_block; i++) {
3575 if (i == inode_offset)
3576 continue;
3577 if (ext4_test_bit(i, bitmap_bh->b_data))
3578 break;
3579 }
3580 brelse(bitmap_bh);
3581 if (i == start + inodes_per_block) {
3582 /* all other inodes are free, so skip I/O */
3583 memset(bh->b_data, 0, bh->b_size);
3584 set_buffer_uptodate(bh);
3585 unlock_buffer(bh);
3586 goto has_buffer;
3587 }
3588 }
3589
3590make_io:
3591 /*
3592 * If we need to do any I/O, try to pre-readahead extra
3593 * blocks from the inode table.
3594 */
3595 if (EXT4_SB(sb)->s_inode_readahead_blks) {
3596 ext4_fsblk_t b, end, table;
3597 unsigned num;
3598
3599 table = ext4_inode_table(sb, gdp);
3600 /* s_inode_readahead_blks is always a power of 2 */
3601 b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
3602 if (table > b)
3603 b = table;
3604 end = b + EXT4_SB(sb)->s_inode_readahead_blks;
3605 num = EXT4_INODES_PER_GROUP(sb);
3606 if (ext4_has_group_desc_csum(sb))
3607 num -= ext4_itable_unused_count(sb, gdp);
3608 table += num / inodes_per_block;
3609 if (end > table)
3610 end = table;
3611 while (b <= end)
3612 sb_breadahead(sb, b++);
3613 }
3614
3615 /*
3616 * There are other valid inodes in the buffer, this inode
3617 * has in-inode xattrs, or we don't have this inode in memory.
3618 * Read the block from disk.
3619 */
3620 trace_ext4_load_inode(inode);
3621 get_bh(bh);
3622 bh->b_end_io = end_buffer_read_sync;
3623 submit_bh(READ | REQ_META | REQ_PRIO, bh);
3624 wait_on_buffer(bh);
3625 if (!buffer_uptodate(bh)) {
3626 EXT4_ERROR_INODE_BLOCK(inode, block,
3627 "unable to read itable block");
3628 brelse(bh);
3629 return -EIO;
3630 }
3631 }
3632has_buffer:
3633 iloc->bh = bh;
3634 return 0;
3635}
3636
3637int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
3638{
3639 /* We have all inode data except xattrs in memory here. */
3640 return __ext4_get_inode_loc(inode, iloc,
3641 !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
3642}
3643
3644void ext4_set_inode_flags(struct inode *inode)
3645{
3646 unsigned int flags = EXT4_I(inode)->i_flags;
3647
3648 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
3649 if (flags & EXT4_SYNC_FL)
3650 inode->i_flags |= S_SYNC;
3651 if (flags & EXT4_APPEND_FL)
3652 inode->i_flags |= S_APPEND;
3653 if (flags & EXT4_IMMUTABLE_FL)
3654 inode->i_flags |= S_IMMUTABLE;
3655 if (flags & EXT4_NOATIME_FL)
3656 inode->i_flags |= S_NOATIME;
3657 if (flags & EXT4_DIRSYNC_FL)
3658 inode->i_flags |= S_DIRSYNC;
3659}
3660
3661/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
3662void ext4_get_inode_flags(struct ext4_inode_info *ei)
3663{
3664 unsigned int vfs_fl;
3665 unsigned long old_fl, new_fl;
3666
3667 do {
3668 vfs_fl = ei->vfs_inode.i_flags;
3669 old_fl = ei->i_flags;
3670 new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
3671 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
3672 EXT4_DIRSYNC_FL);
3673 if (vfs_fl & S_SYNC)
3674 new_fl |= EXT4_SYNC_FL;
3675 if (vfs_fl & S_APPEND)
3676 new_fl |= EXT4_APPEND_FL;
3677 if (vfs_fl & S_IMMUTABLE)
3678 new_fl |= EXT4_IMMUTABLE_FL;
3679 if (vfs_fl & S_NOATIME)
3680 new_fl |= EXT4_NOATIME_FL;
3681 if (vfs_fl & S_DIRSYNC)
3682 new_fl |= EXT4_DIRSYNC_FL;
3683 } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
3684}
3685
3686static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
3687 struct ext4_inode_info *ei)
3688{
3689 blkcnt_t i_blocks ;
3690 struct inode *inode = &(ei->vfs_inode);
3691 struct super_block *sb = inode->i_sb;
3692
3693 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3694 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
3695 /* we are using combined 48 bit field */
3696 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
3697 le32_to_cpu(raw_inode->i_blocks_lo);
3698 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
3699 /* i_blocks represent file system block size */
3700 return i_blocks << (inode->i_blkbits - 9);
3701 } else {
3702 return i_blocks;
3703 }
3704 } else {
3705 return le32_to_cpu(raw_inode->i_blocks_lo);
3706 }
3707}
3708
3709struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
3710{
3711 struct ext4_iloc iloc;
3712 struct ext4_inode *raw_inode;
3713 struct ext4_inode_info *ei;
3714 struct inode *inode;
3715 journal_t *journal = EXT4_SB(sb)->s_journal;
3716 long ret;
3717 int block;
3718 uid_t i_uid;
3719 gid_t i_gid;
3720
3721 inode = iget_locked(sb, ino);
3722 if (!inode)
3723 return ERR_PTR(-ENOMEM);
3724 if (!(inode->i_state & I_NEW))
3725 return inode;
3726
3727 ei = EXT4_I(inode);
3728 iloc.bh = NULL;
3729
3730 ret = __ext4_get_inode_loc(inode, &iloc, 0);
3731 if (ret < 0)
3732 goto bad_inode;
3733 raw_inode = ext4_raw_inode(&iloc);
3734
3735 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3736 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
3737 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
3738 EXT4_INODE_SIZE(inode->i_sb)) {
3739 EXT4_ERROR_INODE(inode, "bad extra_isize (%u != %u)",
3740 EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize,
3741 EXT4_INODE_SIZE(inode->i_sb));
3742 ret = -EIO;
3743 goto bad_inode;
3744 }
3745 } else
3746 ei->i_extra_isize = 0;
3747
3748 /* Precompute checksum seed for inode metadata */
3749 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3750 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
3751 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3752 __u32 csum;
3753 __le32 inum = cpu_to_le32(inode->i_ino);
3754 __le32 gen = raw_inode->i_generation;
3755 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
3756 sizeof(inum));
3757 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
3758 sizeof(gen));
3759 }
3760
3761 if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
3762 EXT4_ERROR_INODE(inode, "checksum invalid");
3763 ret = -EIO;
3764 goto bad_inode;
3765 }
3766
3767 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
3768 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
3769 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
3770 if (!(test_opt(inode->i_sb, NO_UID32))) {
3771 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
3772 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
3773 }
3774 i_uid_write(inode, i_uid);
3775 i_gid_write(inode, i_gid);
3776 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
3777
3778 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
3779 ei->i_dir_start_lookup = 0;
3780 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
3781 /* We now have enough fields to check if the inode was active or not.
3782 * This is needed because nfsd might try to access dead inodes
3783 * the test is that same one that e2fsck uses
3784 * NeilBrown 1999oct15
3785 */
3786 if (inode->i_nlink == 0) {
3787 if (inode->i_mode == 0 ||
3788 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
3789 /* this inode is deleted */
3790 ret = -ESTALE;
3791 goto bad_inode;
3792 }
3793 /* The only unlinked inodes we let through here have
3794 * valid i_mode and are being read by the orphan
3795 * recovery code: that's fine, we're about to complete
3796 * the process of deleting those. */
3797 }
3798 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
3799 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
3800 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
3801 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
3802 ei->i_file_acl |=
3803 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
3804 inode->i_size = ext4_isize(raw_inode);
3805 ei->i_disksize = inode->i_size;
3806#ifdef CONFIG_QUOTA
3807 ei->i_reserved_quota = 0;
3808#endif
3809 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
3810 ei->i_block_group = iloc.block_group;
3811 ei->i_last_alloc_group = ~0;
3812 /*
3813 * NOTE! The in-memory inode i_data array is in little-endian order
3814 * even on big-endian machines: we do NOT byteswap the block numbers!
3815 */
3816 for (block = 0; block < EXT4_N_BLOCKS; block++)
3817 ei->i_data[block] = raw_inode->i_block[block];
3818 INIT_LIST_HEAD(&ei->i_orphan);
3819
3820 /*
3821 * Set transaction id's of transactions that have to be committed
3822 * to finish f[data]sync. We set them to currently running transaction
3823 * as we cannot be sure that the inode or some of its metadata isn't
3824 * part of the transaction - the inode could have been reclaimed and
3825 * now it is reread from disk.
3826 */
3827 if (journal) {
3828 transaction_t *transaction;
3829 tid_t tid;
3830
3831 read_lock(&journal->j_state_lock);
3832 if (journal->j_running_transaction)
3833 transaction = journal->j_running_transaction;
3834 else
3835 transaction = journal->j_committing_transaction;
3836 if (transaction)
3837 tid = transaction->t_tid;
3838 else
3839 tid = journal->j_commit_sequence;
3840 read_unlock(&journal->j_state_lock);
3841 ei->i_sync_tid = tid;
3842 ei->i_datasync_tid = tid;
3843 }
3844
3845 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3846 if (ei->i_extra_isize == 0) {
3847 /* The extra space is currently unused. Use it. */
3848 ei->i_extra_isize = sizeof(struct ext4_inode) -
3849 EXT4_GOOD_OLD_INODE_SIZE;
3850 } else {
3851 __le32 *magic = (void *)raw_inode +
3852 EXT4_GOOD_OLD_INODE_SIZE +
3853 ei->i_extra_isize;
3854 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
3855 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
3856 }
3857 }
3858
3859 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
3860 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
3861 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
3862 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
3863
3864 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
3865 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3866 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
3867 inode->i_version |=
3868 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
3869 }
3870
3871 ret = 0;
3872 if (ei->i_file_acl &&
3873 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
3874 EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
3875 ei->i_file_acl);
3876 ret = -EIO;
3877 goto bad_inode;
3878 } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
3879 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3880 (S_ISLNK(inode->i_mode) &&
3881 !ext4_inode_is_fast_symlink(inode)))
3882 /* Validate extent which is part of inode */
3883 ret = ext4_ext_check_inode(inode);
3884 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
3885 (S_ISLNK(inode->i_mode) &&
3886 !ext4_inode_is_fast_symlink(inode))) {
3887 /* Validate block references which are part of inode */
3888 ret = ext4_ind_check_inode(inode);
3889 }
3890 if (ret)
3891 goto bad_inode;
3892
3893 if (S_ISREG(inode->i_mode)) {
3894 inode->i_op = &ext4_file_inode_operations;
3895 inode->i_fop = &ext4_file_operations;
3896 ext4_set_aops(inode);
3897 } else if (S_ISDIR(inode->i_mode)) {
3898 inode->i_op = &ext4_dir_inode_operations;
3899 inode->i_fop = &ext4_dir_operations;
3900 } else if (S_ISLNK(inode->i_mode)) {
3901 if (ext4_inode_is_fast_symlink(inode)) {
3902 inode->i_op = &ext4_fast_symlink_inode_operations;
3903 nd_terminate_link(ei->i_data, inode->i_size,
3904 sizeof(ei->i_data) - 1);
3905 } else {
3906 inode->i_op = &ext4_symlink_inode_operations;
3907 ext4_set_aops(inode);
3908 }
3909 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
3910 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
3911 inode->i_op = &ext4_special_inode_operations;
3912 if (raw_inode->i_block[0])
3913 init_special_inode(inode, inode->i_mode,
3914 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3915 else
3916 init_special_inode(inode, inode->i_mode,
3917 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3918 } else {
3919 ret = -EIO;
3920 EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
3921 goto bad_inode;
3922 }
3923 brelse(iloc.bh);
3924 ext4_set_inode_flags(inode);
3925 unlock_new_inode(inode);
3926 return inode;
3927
3928bad_inode:
3929 brelse(iloc.bh);
3930 iget_failed(inode);
3931 return ERR_PTR(ret);
3932}
3933
3934static int ext4_inode_blocks_set(handle_t *handle,
3935 struct ext4_inode *raw_inode,
3936 struct ext4_inode_info *ei)
3937{
3938 struct inode *inode = &(ei->vfs_inode);
3939 u64 i_blocks = inode->i_blocks;
3940 struct super_block *sb = inode->i_sb;
3941
3942 if (i_blocks <= ~0U) {
3943 /*
3944 * i_blocks can be represnted in a 32 bit variable
3945 * as multiple of 512 bytes
3946 */
3947 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3948 raw_inode->i_blocks_high = 0;
3949 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
3950 return 0;
3951 }
3952 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
3953 return -EFBIG;
3954
3955 if (i_blocks <= 0xffffffffffffULL) {
3956 /*
3957 * i_blocks can be represented in a 48 bit variable
3958 * as multiple of 512 bytes
3959 */
3960 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3961 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
3962 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
3963 } else {
3964 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
3965 /* i_block is stored in file system block size */
3966 i_blocks = i_blocks >> (inode->i_blkbits - 9);
3967 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3968 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
3969 }
3970 return 0;
3971}
3972
3973/*
3974 * Post the struct inode info into an on-disk inode location in the
3975 * buffer-cache. This gobbles the caller's reference to the
3976 * buffer_head in the inode location struct.
3977 *
3978 * The caller must have write access to iloc->bh.
3979 */
3980static int ext4_do_update_inode(handle_t *handle,
3981 struct inode *inode,
3982 struct ext4_iloc *iloc)
3983{
3984 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
3985 struct ext4_inode_info *ei = EXT4_I(inode);
3986 struct buffer_head *bh = iloc->bh;
3987 int err = 0, rc, block;
3988 uid_t i_uid;
3989 gid_t i_gid;
3990
3991 /* For fields not not tracking in the in-memory inode,
3992 * initialise them to zero for new inodes. */
3993 if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
3994 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
3995
3996 ext4_get_inode_flags(ei);
3997 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3998 i_uid = i_uid_read(inode);
3999 i_gid = i_gid_read(inode);
4000 if (!(test_opt(inode->i_sb, NO_UID32))) {
4001 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4002 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4003/*
4004 * Fix up interoperability with old kernels. Otherwise, old inodes get
4005 * re-used with the upper 16 bits of the uid/gid intact
4006 */
4007 if (!ei->i_dtime) {
4008 raw_inode->i_uid_high =
4009 cpu_to_le16(high_16_bits(i_uid));
4010 raw_inode->i_gid_high =
4011 cpu_to_le16(high_16_bits(i_gid));
4012 } else {
4013 raw_inode->i_uid_high = 0;
4014 raw_inode->i_gid_high = 0;
4015 }
4016 } else {
4017 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4018 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4019 raw_inode->i_uid_high = 0;
4020 raw_inode->i_gid_high = 0;
4021 }
4022 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4023
4024 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4025 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4026 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4027 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4028
4029 if (ext4_inode_blocks_set(handle, raw_inode, ei))
4030 goto out_brelse;
4031 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4032 raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4033 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4034 cpu_to_le32(EXT4_OS_HURD))
4035 raw_inode->i_file_acl_high =
4036 cpu_to_le16(ei->i_file_acl >> 32);
4037 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4038 ext4_isize_set(raw_inode, ei->i_disksize);
4039 if (ei->i_disksize > 0x7fffffffULL) {
4040 struct super_block *sb = inode->i_sb;
4041 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
4042 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
4043 EXT4_SB(sb)->s_es->s_rev_level ==
4044 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
4045 /* If this is the first large file
4046 * created, add a flag to the superblock.
4047 */
4048 err = ext4_journal_get_write_access(handle,
4049 EXT4_SB(sb)->s_sbh);
4050 if (err)
4051 goto out_brelse;
4052 ext4_update_dynamic_rev(sb);
4053 EXT4_SET_RO_COMPAT_FEATURE(sb,
4054 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4055 ext4_handle_sync(handle);
4056 err = ext4_handle_dirty_super_now(handle, sb);
4057 }
4058 }
4059 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4060 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4061 if (old_valid_dev(inode->i_rdev)) {
4062 raw_inode->i_block[0] =
4063 cpu_to_le32(old_encode_dev(inode->i_rdev));
4064 raw_inode->i_block[1] = 0;
4065 } else {
4066 raw_inode->i_block[0] = 0;
4067 raw_inode->i_block[1] =
4068 cpu_to_le32(new_encode_dev(inode->i_rdev));
4069 raw_inode->i_block[2] = 0;
4070 }
4071 } else
4072 for (block = 0; block < EXT4_N_BLOCKS; block++)
4073 raw_inode->i_block[block] = ei->i_data[block];
4074
4075 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4076 if (ei->i_extra_isize) {
4077 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4078 raw_inode->i_version_hi =
4079 cpu_to_le32(inode->i_version >> 32);
4080 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4081 }
4082
4083 ext4_inode_csum_set(inode, raw_inode, ei);
4084
4085 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4086 rc = ext4_handle_dirty_metadata(handle, NULL, bh);
4087 if (!err)
4088 err = rc;
4089 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
4090
4091 ext4_update_inode_fsync_trans(handle, inode, 0);
4092out_brelse:
4093 brelse(bh);
4094 ext4_std_error(inode->i_sb, err);
4095 return err;
4096}
4097
4098/*
4099 * ext4_write_inode()
4100 *
4101 * We are called from a few places:
4102 *
4103 * - Within generic_file_write() for O_SYNC files.
4104 * Here, there will be no transaction running. We wait for any running
4105 * trasnaction to commit.
4106 *
4107 * - Within sys_sync(), kupdate and such.
4108 * We wait on commit, if tol to.
4109 *
4110 * - Within prune_icache() (PF_MEMALLOC == true)
4111 * Here we simply return. We can't afford to block kswapd on the
4112 * journal commit.
4113 *
4114 * In all cases it is actually safe for us to return without doing anything,
4115 * because the inode has been copied into a raw inode buffer in
4116 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
4117 * knfsd.
4118 *
4119 * Note that we are absolutely dependent upon all inode dirtiers doing the
4120 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4121 * which we are interested.
4122 *
4123 * It would be a bug for them to not do this. The code:
4124 *
4125 * mark_inode_dirty(inode)
4126 * stuff();
4127 * inode->i_size = expr;
4128 *
4129 * is in error because a kswapd-driven write_inode() could occur while
4130 * `stuff()' is running, and the new i_size will be lost. Plus the inode
4131 * will no longer be on the superblock's dirty inode list.
4132 */
4133int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
4134{
4135 int err;
4136
4137 if (current->flags & PF_MEMALLOC)
4138 return 0;
4139
4140 if (EXT4_SB(inode->i_sb)->s_journal) {
4141 if (ext4_journal_current_handle()) {
4142 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4143 dump_stack();
4144 return -EIO;
4145 }
4146
4147 if (wbc->sync_mode != WB_SYNC_ALL)
4148 return 0;
4149
4150 err = ext4_force_commit(inode->i_sb);
4151 } else {
4152 struct ext4_iloc iloc;
4153
4154 err = __ext4_get_inode_loc(inode, &iloc, 0);
4155 if (err)
4156 return err;
4157 if (wbc->sync_mode == WB_SYNC_ALL)
4158 sync_dirty_buffer(iloc.bh);
4159 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
4160 EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
4161 "IO error syncing inode");
4162 err = -EIO;
4163 }
4164 brelse(iloc.bh);
4165 }
4166 return err;
4167}
4168
4169/*
4170 * ext4_setattr()
4171 *
4172 * Called from notify_change.
4173 *
4174 * We want to trap VFS attempts to truncate the file as soon as
4175 * possible. In particular, we want to make sure that when the VFS
4176 * shrinks i_size, we put the inode on the orphan list and modify
4177 * i_disksize immediately, so that during the subsequent flushing of
4178 * dirty pages and freeing of disk blocks, we can guarantee that any
4179 * commit will leave the blocks being flushed in an unused state on
4180 * disk. (On recovery, the inode will get truncated and the blocks will
4181 * be freed, so we have a strong guarantee that no future commit will
4182 * leave these blocks visible to the user.)
4183 *
4184 * Another thing we have to assure is that if we are in ordered mode
4185 * and inode is still attached to the committing transaction, we must
4186 * we start writeout of all the dirty pages which are being truncated.
4187 * This way we are sure that all the data written in the previous
4188 * transaction are already on disk (truncate waits for pages under
4189 * writeback).
4190 *
4191 * Called with inode->i_mutex down.
4192 */
4193int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4194{
4195 struct inode *inode = dentry->d_inode;
4196 int error, rc = 0;
4197 int orphan = 0;
4198 const unsigned int ia_valid = attr->ia_valid;
4199
4200 error = inode_change_ok(inode, attr);
4201 if (error)
4202 return error;
4203
4204 if (is_quota_modification(inode, attr))
4205 dquot_initialize(inode);
4206 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
4207 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
4208 handle_t *handle;
4209
4210 /* (user+group)*(old+new) structure, inode write (sb,
4211 * inode block, ? - but truncate inode update has it) */
4212 handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
4213 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3);
4214 if (IS_ERR(handle)) {
4215 error = PTR_ERR(handle);
4216 goto err_out;
4217 }
4218 error = dquot_transfer(inode, attr);
4219 if (error) {
4220 ext4_journal_stop(handle);
4221 return error;
4222 }
4223 /* Update corresponding info in inode so that everything is in
4224 * one transaction */
4225 if (attr->ia_valid & ATTR_UID)
4226 inode->i_uid = attr->ia_uid;
4227 if (attr->ia_valid & ATTR_GID)
4228 inode->i_gid = attr->ia_gid;
4229 error = ext4_mark_inode_dirty(handle, inode);
4230 ext4_journal_stop(handle);
4231 }
4232
4233 if (attr->ia_valid & ATTR_SIZE) {
4234 inode_dio_wait(inode);
4235
4236 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4237 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4238
4239 if (attr->ia_size > sbi->s_bitmap_maxbytes)
4240 return -EFBIG;
4241 }
4242 }
4243
4244 if (S_ISREG(inode->i_mode) &&
4245 attr->ia_valid & ATTR_SIZE &&
4246 (attr->ia_size < inode->i_size)) {
4247 handle_t *handle;
4248
4249 handle = ext4_journal_start(inode, 3);
4250 if (IS_ERR(handle)) {
4251 error = PTR_ERR(handle);
4252 goto err_out;
4253 }
4254 if (ext4_handle_valid(handle)) {
4255 error = ext4_orphan_add(handle, inode);
4256 orphan = 1;
4257 }
4258 EXT4_I(inode)->i_disksize = attr->ia_size;
4259 rc = ext4_mark_inode_dirty(handle, inode);
4260 if (!error)
4261 error = rc;
4262 ext4_journal_stop(handle);
4263
4264 if (ext4_should_order_data(inode)) {
4265 error = ext4_begin_ordered_truncate(inode,
4266 attr->ia_size);
4267 if (error) {
4268 /* Do as much error cleanup as possible */
4269 handle = ext4_journal_start(inode, 3);
4270 if (IS_ERR(handle)) {
4271 ext4_orphan_del(NULL, inode);
4272 goto err_out;
4273 }
4274 ext4_orphan_del(handle, inode);
4275 orphan = 0;
4276 ext4_journal_stop(handle);
4277 goto err_out;
4278 }
4279 }
4280 }
4281
4282 if (attr->ia_valid & ATTR_SIZE) {
4283 if (attr->ia_size != i_size_read(inode))
4284 truncate_setsize(inode, attr->ia_size);
4285 ext4_truncate(inode);
4286 }
4287
4288 if (!rc) {
4289 setattr_copy(inode, attr);
4290 mark_inode_dirty(inode);
4291 }
4292
4293 /*
4294 * If the call to ext4_truncate failed to get a transaction handle at
4295 * all, we need to clean up the in-core orphan list manually.
4296 */
4297 if (orphan && inode->i_nlink)
4298 ext4_orphan_del(NULL, inode);
4299
4300 if (!rc && (ia_valid & ATTR_MODE))
4301 rc = ext4_acl_chmod(inode);
4302
4303err_out:
4304 ext4_std_error(inode->i_sb, error);
4305 if (!error)
4306 error = rc;
4307 return error;
4308}
4309
4310int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
4311 struct kstat *stat)
4312{
4313 struct inode *inode;
4314 unsigned long delalloc_blocks;
4315
4316 inode = dentry->d_inode;
4317 generic_fillattr(inode, stat);
4318
4319 /*
4320 * We can't update i_blocks if the block allocation is delayed
4321 * otherwise in the case of system crash before the real block
4322 * allocation is done, we will have i_blocks inconsistent with
4323 * on-disk file blocks.
4324 * We always keep i_blocks updated together with real
4325 * allocation. But to not confuse with user, stat
4326 * will return the blocks that include the delayed allocation
4327 * blocks for this file.
4328 */
4329 delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
4330 EXT4_I(inode)->i_reserved_data_blocks);
4331
4332 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
4333 return 0;
4334}
4335
4336static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4337{
4338 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4339 return ext4_ind_trans_blocks(inode, nrblocks, chunk);
4340 return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
4341}
4342
4343/*
4344 * Account for index blocks, block groups bitmaps and block group
4345 * descriptor blocks if modify datablocks and index blocks
4346 * worse case, the indexs blocks spread over different block groups
4347 *
4348 * If datablocks are discontiguous, they are possible to spread over
4349 * different block groups too. If they are contiuguous, with flexbg,
4350 * they could still across block group boundary.
4351 *
4352 * Also account for superblock, inode, quota and xattr blocks
4353 */
4354static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
4355{
4356 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
4357 int gdpblocks;
4358 int idxblocks;
4359 int ret = 0;
4360
4361 /*
4362 * How many index blocks need to touch to modify nrblocks?
4363 * The "Chunk" flag indicating whether the nrblocks is
4364 * physically contiguous on disk
4365 *
4366 * For Direct IO and fallocate, they calls get_block to allocate
4367 * one single extent at a time, so they could set the "Chunk" flag
4368 */
4369 idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
4370
4371 ret = idxblocks;
4372
4373 /*
4374 * Now let's see how many group bitmaps and group descriptors need
4375 * to account
4376 */
4377 groups = idxblocks;
4378 if (chunk)
4379 groups += 1;
4380 else
4381 groups += nrblocks;
4382
4383 gdpblocks = groups;
4384 if (groups > ngroups)
4385 groups = ngroups;
4386 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
4387 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
4388
4389 /* bitmaps and block group descriptor blocks */
4390 ret += groups + gdpblocks;
4391
4392 /* Blocks for super block, inode, quota and xattr blocks */
4393 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
4394
4395 return ret;
4396}
4397
4398/*
4399 * Calculate the total number of credits to reserve to fit
4400 * the modification of a single pages into a single transaction,
4401 * which may include multiple chunks of block allocations.
4402 *
4403 * This could be called via ext4_write_begin()
4404 *
4405 * We need to consider the worse case, when
4406 * one new block per extent.
4407 */
4408int ext4_writepage_trans_blocks(struct inode *inode)
4409{
4410 int bpp = ext4_journal_blocks_per_page(inode);
4411 int ret;
4412
4413 ret = ext4_meta_trans_blocks(inode, bpp, 0);
4414
4415 /* Account for data blocks for journalled mode */
4416 if (ext4_should_journal_data(inode))
4417 ret += bpp;
4418 return ret;
4419}
4420
4421/*
4422 * Calculate the journal credits for a chunk of data modification.
4423 *
4424 * This is called from DIO, fallocate or whoever calling
4425 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
4426 *
4427 * journal buffers for data blocks are not included here, as DIO
4428 * and fallocate do no need to journal data buffers.
4429 */
4430int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
4431{
4432 return ext4_meta_trans_blocks(inode, nrblocks, 1);
4433}
4434
4435/*
4436 * The caller must have previously called ext4_reserve_inode_write().
4437 * Give this, we know that the caller already has write access to iloc->bh.
4438 */
4439int ext4_mark_iloc_dirty(handle_t *handle,
4440 struct inode *inode, struct ext4_iloc *iloc)
4441{
4442 int err = 0;
4443
4444 if (IS_I_VERSION(inode))
4445 inode_inc_iversion(inode);
4446
4447 /* the do_update_inode consumes one bh->b_count */
4448 get_bh(iloc->bh);
4449
4450 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4451 err = ext4_do_update_inode(handle, inode, iloc);
4452 put_bh(iloc->bh);
4453 return err;
4454}
4455
4456/*
4457 * On success, We end up with an outstanding reference count against
4458 * iloc->bh. This _must_ be cleaned up later.
4459 */
4460
4461int
4462ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
4463 struct ext4_iloc *iloc)
4464{
4465 int err;
4466
4467 err = ext4_get_inode_loc(inode, iloc);
4468 if (!err) {
4469 BUFFER_TRACE(iloc->bh, "get_write_access");
4470 err = ext4_journal_get_write_access(handle, iloc->bh);
4471 if (err) {
4472 brelse(iloc->bh);
4473 iloc->bh = NULL;
4474 }
4475 }
4476 ext4_std_error(inode->i_sb, err);
4477 return err;
4478}
4479
4480/*
4481 * Expand an inode by new_extra_isize bytes.
4482 * Returns 0 on success or negative error number on failure.
4483 */
4484static int ext4_expand_extra_isize(struct inode *inode,
4485 unsigned int new_extra_isize,
4486 struct ext4_iloc iloc,
4487 handle_t *handle)
4488{
4489 struct ext4_inode *raw_inode;
4490 struct ext4_xattr_ibody_header *header;
4491
4492 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
4493 return 0;
4494
4495 raw_inode = ext4_raw_inode(&iloc);
4496
4497 header = IHDR(inode, raw_inode);
4498
4499 /* No extended attributes present */
4500 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
4501 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
4502 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
4503 new_extra_isize);
4504 EXT4_I(inode)->i_extra_isize = new_extra_isize;
4505 return 0;
4506 }
4507
4508 /* try to expand with EAs present */
4509 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
4510 raw_inode, handle);
4511}
4512
4513/*
4514 * What we do here is to mark the in-core inode as clean with respect to inode
4515 * dirtiness (it may still be data-dirty).
4516 * This means that the in-core inode may be reaped by prune_icache
4517 * without having to perform any I/O. This is a very good thing,
4518 * because *any* task may call prune_icache - even ones which
4519 * have a transaction open against a different journal.
4520 *
4521 * Is this cheating? Not really. Sure, we haven't written the
4522 * inode out, but prune_icache isn't a user-visible syncing function.
4523 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
4524 * we start and wait on commits.
4525 *
4526 * Is this efficient/effective? Well, we're being nice to the system
4527 * by cleaning up our inodes proactively so they can be reaped
4528 * without I/O. But we are potentially leaving up to five seconds'
4529 * worth of inodes floating about which prune_icache wants us to
4530 * write out. One way to fix that would be to get prune_icache()
4531 * to do a write_super() to free up some memory. It has the desired
4532 * effect.
4533 */
4534int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4535{
4536 struct ext4_iloc iloc;
4537 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4538 static unsigned int mnt_count;
4539 int err, ret;
4540
4541 might_sleep();
4542 trace_ext4_mark_inode_dirty(inode, _RET_IP_);
4543 err = ext4_reserve_inode_write(handle, inode, &iloc);
4544 if (ext4_handle_valid(handle) &&
4545 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
4546 !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
4547 /*
4548 * We need extra buffer credits since we may write into EA block
4549 * with this same handle. If journal_extend fails, then it will
4550 * only result in a minor loss of functionality for that inode.
4551 * If this is felt to be critical, then e2fsck should be run to
4552 * force a large enough s_min_extra_isize.
4553 */
4554 if ((jbd2_journal_extend(handle,
4555 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
4556 ret = ext4_expand_extra_isize(inode,
4557 sbi->s_want_extra_isize,
4558 iloc, handle);
4559 if (ret) {
4560 ext4_set_inode_state(inode,
4561 EXT4_STATE_NO_EXPAND);
4562 if (mnt_count !=
4563 le16_to_cpu(sbi->s_es->s_mnt_count)) {
4564 ext4_warning(inode->i_sb,
4565 "Unable to expand inode %lu. Delete"
4566 " some EAs or run e2fsck.",
4567 inode->i_ino);
4568 mnt_count =
4569 le16_to_cpu(sbi->s_es->s_mnt_count);
4570 }
4571 }
4572 }
4573 }
4574 if (!err)
4575 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
4576 return err;
4577}
4578
4579/*
4580 * ext4_dirty_inode() is called from __mark_inode_dirty()
4581 *
4582 * We're really interested in the case where a file is being extended.
4583 * i_size has been changed by generic_commit_write() and we thus need
4584 * to include the updated inode in the current transaction.
4585 *
4586 * Also, dquot_alloc_block() will always dirty the inode when blocks
4587 * are allocated to the file.
4588 *
4589 * If the inode is marked synchronous, we don't honour that here - doing
4590 * so would cause a commit on atime updates, which we don't bother doing.
4591 * We handle synchronous inodes at the highest possible level.
4592 */
4593void ext4_dirty_inode(struct inode *inode, int flags)
4594{
4595 handle_t *handle;
4596
4597 handle = ext4_journal_start(inode, 2);
4598 if (IS_ERR(handle))
4599 goto out;
4600
4601 ext4_mark_inode_dirty(handle, inode);
4602
4603 ext4_journal_stop(handle);
4604out:
4605 return;
4606}
4607
4608#if 0
4609/*
4610 * Bind an inode's backing buffer_head into this transaction, to prevent
4611 * it from being flushed to disk early. Unlike
4612 * ext4_reserve_inode_write, this leaves behind no bh reference and
4613 * returns no iloc structure, so the caller needs to repeat the iloc
4614 * lookup to mark the inode dirty later.
4615 */
4616static int ext4_pin_inode(handle_t *handle, struct inode *inode)
4617{
4618 struct ext4_iloc iloc;
4619
4620 int err = 0;
4621 if (handle) {
4622 err = ext4_get_inode_loc(inode, &iloc);
4623 if (!err) {
4624 BUFFER_TRACE(iloc.bh, "get_write_access");
4625 err = jbd2_journal_get_write_access(handle, iloc.bh);
4626 if (!err)
4627 err = ext4_handle_dirty_metadata(handle,
4628 NULL,
4629 iloc.bh);
4630 brelse(iloc.bh);
4631 }
4632 }
4633 ext4_std_error(inode->i_sb, err);
4634 return err;
4635}
4636#endif
4637
4638int ext4_change_inode_journal_flag(struct inode *inode, int val)
4639{
4640 journal_t *journal;
4641 handle_t *handle;
4642 int err;
4643
4644 /*
4645 * We have to be very careful here: changing a data block's
4646 * journaling status dynamically is dangerous. If we write a
4647 * data block to the journal, change the status and then delete
4648 * that block, we risk forgetting to revoke the old log record
4649 * from the journal and so a subsequent replay can corrupt data.
4650 * So, first we make sure that the journal is empty and that
4651 * nobody is changing anything.
4652 */
4653
4654 journal = EXT4_JOURNAL(inode);
4655 if (!journal)
4656 return 0;
4657 if (is_journal_aborted(journal))
4658 return -EROFS;
4659 /* We have to allocate physical blocks for delalloc blocks
4660 * before flushing journal. otherwise delalloc blocks can not
4661 * be allocated any more. even more truncate on delalloc blocks
4662 * could trigger BUG by flushing delalloc blocks in journal.
4663 * There is no delalloc block in non-journal data mode.
4664 */
4665 if (val && test_opt(inode->i_sb, DELALLOC)) {
4666 err = ext4_alloc_da_blocks(inode);
4667 if (err < 0)
4668 return err;
4669 }
4670
4671 jbd2_journal_lock_updates(journal);
4672
4673 /*
4674 * OK, there are no updates running now, and all cached data is
4675 * synced to disk. We are now in a completely consistent state
4676 * which doesn't have anything in the journal, and we know that
4677 * no filesystem updates are running, so it is safe to modify
4678 * the inode's in-core data-journaling state flag now.
4679 */
4680
4681 if (val)
4682 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
4683 else {
4684 jbd2_journal_flush(journal);
4685 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
4686 }
4687 ext4_set_aops(inode);
4688
4689 jbd2_journal_unlock_updates(journal);
4690
4691 /* Finally we can mark the inode as dirty. */
4692
4693 handle = ext4_journal_start(inode, 1);
4694 if (IS_ERR(handle))
4695 return PTR_ERR(handle);
4696
4697 err = ext4_mark_inode_dirty(handle, inode);
4698 ext4_handle_sync(handle);
4699 ext4_journal_stop(handle);
4700 ext4_std_error(inode->i_sb, err);
4701
4702 return err;
4703}
4704
4705static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
4706{
4707 return !buffer_mapped(bh);
4708}
4709
4710int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
4711{
4712 struct page *page = vmf->page;
4713 loff_t size;
4714 unsigned long len;
4715 int ret;
4716 struct file *file = vma->vm_file;
4717 struct inode *inode = file->f_path.dentry->d_inode;
4718 struct address_space *mapping = inode->i_mapping;
4719 handle_t *handle;
4720 get_block_t *get_block;
4721 int retries = 0;
4722
4723 /*
4724 * This check is racy but catches the common case. We rely on
4725 * __block_page_mkwrite() to do a reliable check.
4726 */
4727 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
4728 /* Delalloc case is easy... */
4729 if (test_opt(inode->i_sb, DELALLOC) &&
4730 !ext4_should_journal_data(inode) &&
4731 !ext4_nonda_switch(inode->i_sb)) {
4732 do {
4733 ret = __block_page_mkwrite(vma, vmf,
4734 ext4_da_get_block_prep);
4735 } while (ret == -ENOSPC &&
4736 ext4_should_retry_alloc(inode->i_sb, &retries));
4737 goto out_ret;
4738 }
4739
4740 lock_page(page);
4741 size = i_size_read(inode);
4742 /* Page got truncated from under us? */
4743 if (page->mapping != mapping || page_offset(page) > size) {
4744 unlock_page(page);
4745 ret = VM_FAULT_NOPAGE;
4746 goto out;
4747 }
4748
4749 if (page->index == size >> PAGE_CACHE_SHIFT)
4750 len = size & ~PAGE_CACHE_MASK;
4751 else
4752 len = PAGE_CACHE_SIZE;
4753 /*
4754 * Return if we have all the buffers mapped. This avoids the need to do
4755 * journal_start/journal_stop which can block and take a long time
4756 */
4757 if (page_has_buffers(page)) {
4758 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
4759 ext4_bh_unmapped)) {
4760 /* Wait so that we don't change page under IO */
4761 wait_on_page_writeback(page);
4762 ret = VM_FAULT_LOCKED;
4763 goto out;
4764 }
4765 }
4766 unlock_page(page);
4767 /* OK, we need to fill the hole... */
4768 if (ext4_should_dioread_nolock(inode))
4769 get_block = ext4_get_block_write;
4770 else
4771 get_block = ext4_get_block;
4772retry_alloc:
4773 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
4774 if (IS_ERR(handle)) {
4775 ret = VM_FAULT_SIGBUS;
4776 goto out;
4777 }
4778 ret = __block_page_mkwrite(vma, vmf, get_block);
4779 if (!ret && ext4_should_journal_data(inode)) {
4780 if (walk_page_buffers(handle, page_buffers(page), 0,
4781 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {
4782 unlock_page(page);
4783 ret = VM_FAULT_SIGBUS;
4784 ext4_journal_stop(handle);
4785 goto out;
4786 }
4787 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
4788 }
4789 ext4_journal_stop(handle);
4790 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
4791 goto retry_alloc;
4792out_ret:
4793 ret = block_page_mkwrite_return(ret);
4794out:
4795 return ret;
4796}