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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/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}
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#include <linux/aio.h>
41#include <linux/bitops.h>
42
43#include "ext4_jbd2.h"
44#include "xattr.h"
45#include "acl.h"
46#include "truncate.h"
47
48#include <trace/events/ext4.h>
49
50#define MPAGE_DA_EXTENT_TAIL 0x01
51
52static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
53 struct ext4_inode_info *ei)
54{
55 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
56 __u16 csum_lo;
57 __u16 csum_hi = 0;
58 __u32 csum;
59
60 csum_lo = le16_to_cpu(raw->i_checksum_lo);
61 raw->i_checksum_lo = 0;
62 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
63 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
64 csum_hi = le16_to_cpu(raw->i_checksum_hi);
65 raw->i_checksum_hi = 0;
66 }
67
68 csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw,
69 EXT4_INODE_SIZE(inode->i_sb));
70
71 raw->i_checksum_lo = cpu_to_le16(csum_lo);
72 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
73 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
74 raw->i_checksum_hi = cpu_to_le16(csum_hi);
75
76 return csum;
77}
78
79static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
80 struct ext4_inode_info *ei)
81{
82 __u32 provided, calculated;
83
84 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
85 cpu_to_le32(EXT4_OS_LINUX) ||
86 !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
87 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
88 return 1;
89
90 provided = le16_to_cpu(raw->i_checksum_lo);
91 calculated = ext4_inode_csum(inode, raw, ei);
92 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
93 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
94 provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
95 else
96 calculated &= 0xFFFF;
97
98 return provided == calculated;
99}
100
101static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
102 struct ext4_inode_info *ei)
103{
104 __u32 csum;
105
106 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
107 cpu_to_le32(EXT4_OS_LINUX) ||
108 !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
109 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
110 return;
111
112 csum = ext4_inode_csum(inode, raw, ei);
113 raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
114 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
115 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
116 raw->i_checksum_hi = cpu_to_le16(csum >> 16);
117}
118
119static inline int ext4_begin_ordered_truncate(struct inode *inode,
120 loff_t new_size)
121{
122 trace_ext4_begin_ordered_truncate(inode, new_size);
123 /*
124 * If jinode is zero, then we never opened the file for
125 * writing, so there's no need to call
126 * jbd2_journal_begin_ordered_truncate() since there's no
127 * outstanding writes we need to flush.
128 */
129 if (!EXT4_I(inode)->jinode)
130 return 0;
131 return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
132 EXT4_I(inode)->jinode,
133 new_size);
134}
135
136static void ext4_invalidatepage(struct page *page, unsigned int offset,
137 unsigned int length);
138static int __ext4_journalled_writepage(struct page *page, unsigned int len);
139static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
140static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
141 int pextents);
142
143/*
144 * Test whether an inode is a fast symlink.
145 */
146static int ext4_inode_is_fast_symlink(struct inode *inode)
147{
148 int ea_blocks = EXT4_I(inode)->i_file_acl ?
149 EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
150
151 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
152}
153
154/*
155 * Restart the transaction associated with *handle. This does a commit,
156 * so before we call here everything must be consistently dirtied against
157 * this transaction.
158 */
159int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
160 int nblocks)
161{
162 int ret;
163
164 /*
165 * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
166 * moment, get_block can be called only for blocks inside i_size since
167 * page cache has been already dropped and writes are blocked by
168 * i_mutex. So we can safely drop the i_data_sem here.
169 */
170 BUG_ON(EXT4_JOURNAL(inode) == NULL);
171 jbd_debug(2, "restarting handle %p\n", handle);
172 up_write(&EXT4_I(inode)->i_data_sem);
173 ret = ext4_journal_restart(handle, nblocks);
174 down_write(&EXT4_I(inode)->i_data_sem);
175 ext4_discard_preallocations(inode);
176
177 return ret;
178}
179
180/*
181 * Called at the last iput() if i_nlink is zero.
182 */
183void ext4_evict_inode(struct inode *inode)
184{
185 handle_t *handle;
186 int err;
187
188 trace_ext4_evict_inode(inode);
189
190 if (inode->i_nlink) {
191 /*
192 * When journalling data dirty buffers are tracked only in the
193 * journal. So although mm thinks everything is clean and
194 * ready for reaping the inode might still have some pages to
195 * write in the running transaction or waiting to be
196 * checkpointed. Thus calling jbd2_journal_invalidatepage()
197 * (via truncate_inode_pages()) to discard these buffers can
198 * cause data loss. Also even if we did not discard these
199 * buffers, we would have no way to find them after the inode
200 * is reaped and thus user could see stale data if he tries to
201 * read them before the transaction is checkpointed. So be
202 * careful and force everything to disk here... We use
203 * ei->i_datasync_tid to store the newest transaction
204 * containing inode's data.
205 *
206 * Note that directories do not have this problem because they
207 * don't use page cache.
208 */
209 if (ext4_should_journal_data(inode) &&
210 (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
211 inode->i_ino != EXT4_JOURNAL_INO) {
212 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
213 tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
214
215 jbd2_complete_transaction(journal, commit_tid);
216 filemap_write_and_wait(&inode->i_data);
217 }
218 truncate_inode_pages_final(&inode->i_data);
219
220 WARN_ON(atomic_read(&EXT4_I(inode)->i_ioend_count));
221 goto no_delete;
222 }
223
224 if (!is_bad_inode(inode))
225 dquot_initialize(inode);
226
227 if (ext4_should_order_data(inode))
228 ext4_begin_ordered_truncate(inode, 0);
229 truncate_inode_pages_final(&inode->i_data);
230
231 WARN_ON(atomic_read(&EXT4_I(inode)->i_ioend_count));
232 if (is_bad_inode(inode))
233 goto no_delete;
234
235 /*
236 * Protect us against freezing - iput() caller didn't have to have any
237 * protection against it
238 */
239 sb_start_intwrite(inode->i_sb);
240 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
241 ext4_blocks_for_truncate(inode)+3);
242 if (IS_ERR(handle)) {
243 ext4_std_error(inode->i_sb, PTR_ERR(handle));
244 /*
245 * If we're going to skip the normal cleanup, we still need to
246 * make sure that the in-core orphan linked list is properly
247 * cleaned up.
248 */
249 ext4_orphan_del(NULL, inode);
250 sb_end_intwrite(inode->i_sb);
251 goto no_delete;
252 }
253
254 if (IS_SYNC(inode))
255 ext4_handle_sync(handle);
256 inode->i_size = 0;
257 err = ext4_mark_inode_dirty(handle, inode);
258 if (err) {
259 ext4_warning(inode->i_sb,
260 "couldn't mark inode dirty (err %d)", err);
261 goto stop_handle;
262 }
263 if (inode->i_blocks)
264 ext4_truncate(inode);
265
266 /*
267 * ext4_ext_truncate() doesn't reserve any slop when it
268 * restarts journal transactions; therefore there may not be
269 * enough credits left in the handle to remove the inode from
270 * the orphan list and set the dtime field.
271 */
272 if (!ext4_handle_has_enough_credits(handle, 3)) {
273 err = ext4_journal_extend(handle, 3);
274 if (err > 0)
275 err = ext4_journal_restart(handle, 3);
276 if (err != 0) {
277 ext4_warning(inode->i_sb,
278 "couldn't extend journal (err %d)", err);
279 stop_handle:
280 ext4_journal_stop(handle);
281 ext4_orphan_del(NULL, inode);
282 sb_end_intwrite(inode->i_sb);
283 goto no_delete;
284 }
285 }
286
287 /*
288 * Kill off the orphan record which ext4_truncate created.
289 * AKPM: I think this can be inside the above `if'.
290 * Note that ext4_orphan_del() has to be able to cope with the
291 * deletion of a non-existent orphan - this is because we don't
292 * know if ext4_truncate() actually created an orphan record.
293 * (Well, we could do this if we need to, but heck - it works)
294 */
295 ext4_orphan_del(handle, inode);
296 EXT4_I(inode)->i_dtime = get_seconds();
297
298 /*
299 * One subtle ordering requirement: if anything has gone wrong
300 * (transaction abort, IO errors, whatever), then we can still
301 * do these next steps (the fs will already have been marked as
302 * having errors), but we can't free the inode if the mark_dirty
303 * fails.
304 */
305 if (ext4_mark_inode_dirty(handle, inode))
306 /* If that failed, just do the required in-core inode clear. */
307 ext4_clear_inode(inode);
308 else
309 ext4_free_inode(handle, inode);
310 ext4_journal_stop(handle);
311 sb_end_intwrite(inode->i_sb);
312 return;
313no_delete:
314 ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
315}
316
317#ifdef CONFIG_QUOTA
318qsize_t *ext4_get_reserved_space(struct inode *inode)
319{
320 return &EXT4_I(inode)->i_reserved_quota;
321}
322#endif
323
324/*
325 * Calculate the number of metadata blocks need to reserve
326 * to allocate a block located at @lblock
327 */
328static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
329{
330 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
331 return ext4_ext_calc_metadata_amount(inode, lblock);
332
333 return ext4_ind_calc_metadata_amount(inode, lblock);
334}
335
336/*
337 * Called with i_data_sem down, which is important since we can call
338 * ext4_discard_preallocations() from here.
339 */
340void ext4_da_update_reserve_space(struct inode *inode,
341 int used, int quota_claim)
342{
343 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
344 struct ext4_inode_info *ei = EXT4_I(inode);
345
346 spin_lock(&ei->i_block_reservation_lock);
347 trace_ext4_da_update_reserve_space(inode, used, quota_claim);
348 if (unlikely(used > ei->i_reserved_data_blocks)) {
349 ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
350 "with only %d reserved data blocks",
351 __func__, inode->i_ino, used,
352 ei->i_reserved_data_blocks);
353 WARN_ON(1);
354 used = ei->i_reserved_data_blocks;
355 }
356
357 if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks)) {
358 ext4_warning(inode->i_sb, "ino %lu, allocated %d "
359 "with only %d reserved metadata blocks "
360 "(releasing %d blocks with reserved %d data blocks)",
361 inode->i_ino, ei->i_allocated_meta_blocks,
362 ei->i_reserved_meta_blocks, used,
363 ei->i_reserved_data_blocks);
364 WARN_ON(1);
365 ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
366 }
367
368 /* Update per-inode reservations */
369 ei->i_reserved_data_blocks -= used;
370 ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
371 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
372 used + ei->i_allocated_meta_blocks);
373 ei->i_allocated_meta_blocks = 0;
374
375 if (ei->i_reserved_data_blocks == 0) {
376 /*
377 * We can release all of the reserved metadata blocks
378 * only when we have written all of the delayed
379 * allocation blocks.
380 */
381 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
382 ei->i_reserved_meta_blocks);
383 ei->i_reserved_meta_blocks = 0;
384 ei->i_da_metadata_calc_len = 0;
385 }
386 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
387
388 /* Update quota subsystem for data blocks */
389 if (quota_claim)
390 dquot_claim_block(inode, EXT4_C2B(sbi, used));
391 else {
392 /*
393 * We did fallocate with an offset that is already delayed
394 * allocated. So on delayed allocated writeback we should
395 * not re-claim the quota for fallocated blocks.
396 */
397 dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
398 }
399
400 /*
401 * If we have done all the pending block allocations and if
402 * there aren't any writers on the inode, we can discard the
403 * inode's preallocations.
404 */
405 if ((ei->i_reserved_data_blocks == 0) &&
406 (atomic_read(&inode->i_writecount) == 0))
407 ext4_discard_preallocations(inode);
408}
409
410static int __check_block_validity(struct inode *inode, const char *func,
411 unsigned int line,
412 struct ext4_map_blocks *map)
413{
414 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
415 map->m_len)) {
416 ext4_error_inode(inode, func, line, map->m_pblk,
417 "lblock %lu mapped to illegal pblock "
418 "(length %d)", (unsigned long) map->m_lblk,
419 map->m_len);
420 return -EIO;
421 }
422 return 0;
423}
424
425#define check_block_validity(inode, map) \
426 __check_block_validity((inode), __func__, __LINE__, (map))
427
428#ifdef ES_AGGRESSIVE_TEST
429static void ext4_map_blocks_es_recheck(handle_t *handle,
430 struct inode *inode,
431 struct ext4_map_blocks *es_map,
432 struct ext4_map_blocks *map,
433 int flags)
434{
435 int retval;
436
437 map->m_flags = 0;
438 /*
439 * There is a race window that the result is not the same.
440 * e.g. xfstests #223 when dioread_nolock enables. The reason
441 * is that we lookup a block mapping in extent status tree with
442 * out taking i_data_sem. So at the time the unwritten extent
443 * could be converted.
444 */
445 if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
446 down_read((&EXT4_I(inode)->i_data_sem));
447 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
448 retval = ext4_ext_map_blocks(handle, inode, map, flags &
449 EXT4_GET_BLOCKS_KEEP_SIZE);
450 } else {
451 retval = ext4_ind_map_blocks(handle, inode, map, flags &
452 EXT4_GET_BLOCKS_KEEP_SIZE);
453 }
454 if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
455 up_read((&EXT4_I(inode)->i_data_sem));
456 /*
457 * Clear EXT4_MAP_FROM_CLUSTER and EXT4_MAP_BOUNDARY flag
458 * because it shouldn't be marked in es_map->m_flags.
459 */
460 map->m_flags &= ~(EXT4_MAP_FROM_CLUSTER | EXT4_MAP_BOUNDARY);
461
462 /*
463 * We don't check m_len because extent will be collpased in status
464 * tree. So the m_len might not equal.
465 */
466 if (es_map->m_lblk != map->m_lblk ||
467 es_map->m_flags != map->m_flags ||
468 es_map->m_pblk != map->m_pblk) {
469 printk("ES cache assertion failed for inode: %lu "
470 "es_cached ex [%d/%d/%llu/%x] != "
471 "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
472 inode->i_ino, es_map->m_lblk, es_map->m_len,
473 es_map->m_pblk, es_map->m_flags, map->m_lblk,
474 map->m_len, map->m_pblk, map->m_flags,
475 retval, flags);
476 }
477}
478#endif /* ES_AGGRESSIVE_TEST */
479
480/*
481 * The ext4_map_blocks() function tries to look up the requested blocks,
482 * and returns if the blocks are already mapped.
483 *
484 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
485 * and store the allocated blocks in the result buffer head and mark it
486 * mapped.
487 *
488 * If file type is extents based, it will call ext4_ext_map_blocks(),
489 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
490 * based files
491 *
492 * On success, it returns the number of blocks being mapped or allocate.
493 * if create==0 and the blocks are pre-allocated and uninitialized block,
494 * the result buffer head is unmapped. If the create ==1, it will make sure
495 * the buffer head is mapped.
496 *
497 * It returns 0 if plain look up failed (blocks have not been allocated), in
498 * that case, buffer head is unmapped
499 *
500 * It returns the error in case of allocation failure.
501 */
502int ext4_map_blocks(handle_t *handle, struct inode *inode,
503 struct ext4_map_blocks *map, int flags)
504{
505 struct extent_status es;
506 int retval;
507 int ret = 0;
508#ifdef ES_AGGRESSIVE_TEST
509 struct ext4_map_blocks orig_map;
510
511 memcpy(&orig_map, map, sizeof(*map));
512#endif
513
514 map->m_flags = 0;
515 ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
516 "logical block %lu\n", inode->i_ino, flags, map->m_len,
517 (unsigned long) map->m_lblk);
518
519 /*
520 * ext4_map_blocks returns an int, and m_len is an unsigned int
521 */
522 if (unlikely(map->m_len > INT_MAX))
523 map->m_len = INT_MAX;
524
525 /* We can handle the block number less than EXT_MAX_BLOCKS */
526 if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
527 return -EIO;
528
529 /* Lookup extent status tree firstly */
530 if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
531 ext4_es_lru_add(inode);
532 if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
533 map->m_pblk = ext4_es_pblock(&es) +
534 map->m_lblk - es.es_lblk;
535 map->m_flags |= ext4_es_is_written(&es) ?
536 EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
537 retval = es.es_len - (map->m_lblk - es.es_lblk);
538 if (retval > map->m_len)
539 retval = map->m_len;
540 map->m_len = retval;
541 } else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
542 retval = 0;
543 } else {
544 BUG_ON(1);
545 }
546#ifdef ES_AGGRESSIVE_TEST
547 ext4_map_blocks_es_recheck(handle, inode, map,
548 &orig_map, flags);
549#endif
550 goto found;
551 }
552
553 /*
554 * Try to see if we can get the block without requesting a new
555 * file system block.
556 */
557 if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
558 down_read((&EXT4_I(inode)->i_data_sem));
559 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
560 retval = ext4_ext_map_blocks(handle, inode, map, flags &
561 EXT4_GET_BLOCKS_KEEP_SIZE);
562 } else {
563 retval = ext4_ind_map_blocks(handle, inode, map, flags &
564 EXT4_GET_BLOCKS_KEEP_SIZE);
565 }
566 if (retval > 0) {
567 unsigned int status;
568
569 if (unlikely(retval != map->m_len)) {
570 ext4_warning(inode->i_sb,
571 "ES len assertion failed for inode "
572 "%lu: retval %d != map->m_len %d",
573 inode->i_ino, retval, map->m_len);
574 WARN_ON(1);
575 }
576
577 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
578 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
579 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
580 ext4_find_delalloc_range(inode, map->m_lblk,
581 map->m_lblk + map->m_len - 1))
582 status |= EXTENT_STATUS_DELAYED;
583 ret = ext4_es_insert_extent(inode, map->m_lblk,
584 map->m_len, map->m_pblk, status);
585 if (ret < 0)
586 retval = ret;
587 }
588 if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
589 up_read((&EXT4_I(inode)->i_data_sem));
590
591found:
592 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
593 ret = check_block_validity(inode, map);
594 if (ret != 0)
595 return ret;
596 }
597
598 /* If it is only a block(s) look up */
599 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
600 return retval;
601
602 /*
603 * Returns if the blocks have already allocated
604 *
605 * Note that if blocks have been preallocated
606 * ext4_ext_get_block() returns the create = 0
607 * with buffer head unmapped.
608 */
609 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
610 /*
611 * If we need to convert extent to unwritten
612 * we continue and do the actual work in
613 * ext4_ext_map_blocks()
614 */
615 if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
616 return retval;
617
618 /*
619 * Here we clear m_flags because after allocating an new extent,
620 * it will be set again.
621 */
622 map->m_flags &= ~EXT4_MAP_FLAGS;
623
624 /*
625 * New blocks allocate and/or writing to uninitialized extent
626 * will possibly result in updating i_data, so we take
627 * the write lock of i_data_sem, and call get_blocks()
628 * with create == 1 flag.
629 */
630 down_write((&EXT4_I(inode)->i_data_sem));
631
632 /*
633 * if the caller is from delayed allocation writeout path
634 * we have already reserved fs blocks for allocation
635 * let the underlying get_block() function know to
636 * avoid double accounting
637 */
638 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
639 ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
640 /*
641 * We need to check for EXT4 here because migrate
642 * could have changed the inode type in between
643 */
644 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
645 retval = ext4_ext_map_blocks(handle, inode, map, flags);
646 } else {
647 retval = ext4_ind_map_blocks(handle, inode, map, flags);
648
649 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
650 /*
651 * We allocated new blocks which will result in
652 * i_data's format changing. Force the migrate
653 * to fail by clearing migrate flags
654 */
655 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
656 }
657
658 /*
659 * Update reserved blocks/metadata blocks after successful
660 * block allocation which had been deferred till now. We don't
661 * support fallocate for non extent files. So we can update
662 * reserve space here.
663 */
664 if ((retval > 0) &&
665 (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
666 ext4_da_update_reserve_space(inode, retval, 1);
667 }
668 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
669 ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
670
671 if (retval > 0) {
672 unsigned int status;
673
674 if (unlikely(retval != map->m_len)) {
675 ext4_warning(inode->i_sb,
676 "ES len assertion failed for inode "
677 "%lu: retval %d != map->m_len %d",
678 inode->i_ino, retval, map->m_len);
679 WARN_ON(1);
680 }
681
682 /*
683 * If the extent has been zeroed out, we don't need to update
684 * extent status tree.
685 */
686 if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
687 ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
688 if (ext4_es_is_written(&es))
689 goto has_zeroout;
690 }
691 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
692 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
693 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
694 ext4_find_delalloc_range(inode, map->m_lblk,
695 map->m_lblk + map->m_len - 1))
696 status |= EXTENT_STATUS_DELAYED;
697 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
698 map->m_pblk, status);
699 if (ret < 0)
700 retval = ret;
701 }
702
703has_zeroout:
704 up_write((&EXT4_I(inode)->i_data_sem));
705 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
706 ret = check_block_validity(inode, map);
707 if (ret != 0)
708 return ret;
709 }
710 return retval;
711}
712
713/* Maximum number of blocks we map for direct IO at once. */
714#define DIO_MAX_BLOCKS 4096
715
716static int _ext4_get_block(struct inode *inode, sector_t iblock,
717 struct buffer_head *bh, int flags)
718{
719 handle_t *handle = ext4_journal_current_handle();
720 struct ext4_map_blocks map;
721 int ret = 0, started = 0;
722 int dio_credits;
723
724 if (ext4_has_inline_data(inode))
725 return -ERANGE;
726
727 map.m_lblk = iblock;
728 map.m_len = bh->b_size >> inode->i_blkbits;
729
730 if (flags && !(flags & EXT4_GET_BLOCKS_NO_LOCK) && !handle) {
731 /* Direct IO write... */
732 if (map.m_len > DIO_MAX_BLOCKS)
733 map.m_len = DIO_MAX_BLOCKS;
734 dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
735 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
736 dio_credits);
737 if (IS_ERR(handle)) {
738 ret = PTR_ERR(handle);
739 return ret;
740 }
741 started = 1;
742 }
743
744 ret = ext4_map_blocks(handle, inode, &map, flags);
745 if (ret > 0) {
746 ext4_io_end_t *io_end = ext4_inode_aio(inode);
747
748 map_bh(bh, inode->i_sb, map.m_pblk);
749 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
750 if (io_end && io_end->flag & EXT4_IO_END_UNWRITTEN)
751 set_buffer_defer_completion(bh);
752 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
753 ret = 0;
754 }
755 if (started)
756 ext4_journal_stop(handle);
757 return ret;
758}
759
760int ext4_get_block(struct inode *inode, sector_t iblock,
761 struct buffer_head *bh, int create)
762{
763 return _ext4_get_block(inode, iblock, bh,
764 create ? EXT4_GET_BLOCKS_CREATE : 0);
765}
766
767/*
768 * `handle' can be NULL if create is zero
769 */
770struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
771 ext4_lblk_t block, int create, int *errp)
772{
773 struct ext4_map_blocks map;
774 struct buffer_head *bh;
775 int fatal = 0, err;
776
777 J_ASSERT(handle != NULL || create == 0);
778
779 map.m_lblk = block;
780 map.m_len = 1;
781 err = ext4_map_blocks(handle, inode, &map,
782 create ? EXT4_GET_BLOCKS_CREATE : 0);
783
784 /* ensure we send some value back into *errp */
785 *errp = 0;
786
787 if (create && err == 0)
788 err = -ENOSPC; /* should never happen */
789 if (err < 0)
790 *errp = err;
791 if (err <= 0)
792 return NULL;
793
794 bh = sb_getblk(inode->i_sb, map.m_pblk);
795 if (unlikely(!bh)) {
796 *errp = -ENOMEM;
797 return NULL;
798 }
799 if (map.m_flags & EXT4_MAP_NEW) {
800 J_ASSERT(create != 0);
801 J_ASSERT(handle != NULL);
802
803 /*
804 * Now that we do not always journal data, we should
805 * keep in mind whether this should always journal the
806 * new buffer as metadata. For now, regular file
807 * writes use ext4_get_block instead, so it's not a
808 * problem.
809 */
810 lock_buffer(bh);
811 BUFFER_TRACE(bh, "call get_create_access");
812 fatal = ext4_journal_get_create_access(handle, bh);
813 if (!fatal && !buffer_uptodate(bh)) {
814 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
815 set_buffer_uptodate(bh);
816 }
817 unlock_buffer(bh);
818 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
819 err = ext4_handle_dirty_metadata(handle, inode, bh);
820 if (!fatal)
821 fatal = err;
822 } else {
823 BUFFER_TRACE(bh, "not a new buffer");
824 }
825 if (fatal) {
826 *errp = fatal;
827 brelse(bh);
828 bh = NULL;
829 }
830 return bh;
831}
832
833struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
834 ext4_lblk_t block, int create, int *err)
835{
836 struct buffer_head *bh;
837
838 bh = ext4_getblk(handle, inode, block, create, err);
839 if (!bh)
840 return bh;
841 if (buffer_uptodate(bh))
842 return bh;
843 ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
844 wait_on_buffer(bh);
845 if (buffer_uptodate(bh))
846 return bh;
847 put_bh(bh);
848 *err = -EIO;
849 return NULL;
850}
851
852int ext4_walk_page_buffers(handle_t *handle,
853 struct buffer_head *head,
854 unsigned from,
855 unsigned to,
856 int *partial,
857 int (*fn)(handle_t *handle,
858 struct buffer_head *bh))
859{
860 struct buffer_head *bh;
861 unsigned block_start, block_end;
862 unsigned blocksize = head->b_size;
863 int err, ret = 0;
864 struct buffer_head *next;
865
866 for (bh = head, block_start = 0;
867 ret == 0 && (bh != head || !block_start);
868 block_start = block_end, bh = next) {
869 next = bh->b_this_page;
870 block_end = block_start + blocksize;
871 if (block_end <= from || block_start >= to) {
872 if (partial && !buffer_uptodate(bh))
873 *partial = 1;
874 continue;
875 }
876 err = (*fn)(handle, bh);
877 if (!ret)
878 ret = err;
879 }
880 return ret;
881}
882
883/*
884 * To preserve ordering, it is essential that the hole instantiation and
885 * the data write be encapsulated in a single transaction. We cannot
886 * close off a transaction and start a new one between the ext4_get_block()
887 * and the commit_write(). So doing the jbd2_journal_start at the start of
888 * prepare_write() is the right place.
889 *
890 * Also, this function can nest inside ext4_writepage(). In that case, we
891 * *know* that ext4_writepage() has generated enough buffer credits to do the
892 * whole page. So we won't block on the journal in that case, which is good,
893 * because the caller may be PF_MEMALLOC.
894 *
895 * By accident, ext4 can be reentered when a transaction is open via
896 * quota file writes. If we were to commit the transaction while thus
897 * reentered, there can be a deadlock - we would be holding a quota
898 * lock, and the commit would never complete if another thread had a
899 * transaction open and was blocking on the quota lock - a ranking
900 * violation.
901 *
902 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
903 * will _not_ run commit under these circumstances because handle->h_ref
904 * is elevated. We'll still have enough credits for the tiny quotafile
905 * write.
906 */
907int do_journal_get_write_access(handle_t *handle,
908 struct buffer_head *bh)
909{
910 int dirty = buffer_dirty(bh);
911 int ret;
912
913 if (!buffer_mapped(bh) || buffer_freed(bh))
914 return 0;
915 /*
916 * __block_write_begin() could have dirtied some buffers. Clean
917 * the dirty bit as jbd2_journal_get_write_access() could complain
918 * otherwise about fs integrity issues. Setting of the dirty bit
919 * by __block_write_begin() isn't a real problem here as we clear
920 * the bit before releasing a page lock and thus writeback cannot
921 * ever write the buffer.
922 */
923 if (dirty)
924 clear_buffer_dirty(bh);
925 ret = ext4_journal_get_write_access(handle, bh);
926 if (!ret && dirty)
927 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
928 return ret;
929}
930
931static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock,
932 struct buffer_head *bh_result, int create);
933static int ext4_write_begin(struct file *file, struct address_space *mapping,
934 loff_t pos, unsigned len, unsigned flags,
935 struct page **pagep, void **fsdata)
936{
937 struct inode *inode = mapping->host;
938 int ret, needed_blocks;
939 handle_t *handle;
940 int retries = 0;
941 struct page *page;
942 pgoff_t index;
943 unsigned from, to;
944
945 trace_ext4_write_begin(inode, pos, len, flags);
946 /*
947 * Reserve one block more for addition to orphan list in case
948 * we allocate blocks but write fails for some reason
949 */
950 needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
951 index = pos >> PAGE_CACHE_SHIFT;
952 from = pos & (PAGE_CACHE_SIZE - 1);
953 to = from + len;
954
955 if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
956 ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
957 flags, pagep);
958 if (ret < 0)
959 return ret;
960 if (ret == 1)
961 return 0;
962 }
963
964 /*
965 * grab_cache_page_write_begin() can take a long time if the
966 * system is thrashing due to memory pressure, or if the page
967 * is being written back. So grab it first before we start
968 * the transaction handle. This also allows us to allocate
969 * the page (if needed) without using GFP_NOFS.
970 */
971retry_grab:
972 page = grab_cache_page_write_begin(mapping, index, flags);
973 if (!page)
974 return -ENOMEM;
975 unlock_page(page);
976
977retry_journal:
978 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
979 if (IS_ERR(handle)) {
980 page_cache_release(page);
981 return PTR_ERR(handle);
982 }
983
984 lock_page(page);
985 if (page->mapping != mapping) {
986 /* The page got truncated from under us */
987 unlock_page(page);
988 page_cache_release(page);
989 ext4_journal_stop(handle);
990 goto retry_grab;
991 }
992 /* In case writeback began while the page was unlocked */
993 wait_for_stable_page(page);
994
995 if (ext4_should_dioread_nolock(inode))
996 ret = __block_write_begin(page, pos, len, ext4_get_block_write);
997 else
998 ret = __block_write_begin(page, pos, len, ext4_get_block);
999
1000 if (!ret && ext4_should_journal_data(inode)) {
1001 ret = ext4_walk_page_buffers(handle, page_buffers(page),
1002 from, to, NULL,
1003 do_journal_get_write_access);
1004 }
1005
1006 if (ret) {
1007 unlock_page(page);
1008 /*
1009 * __block_write_begin may have instantiated a few blocks
1010 * outside i_size. Trim these off again. Don't need
1011 * i_size_read because we hold i_mutex.
1012 *
1013 * Add inode to orphan list in case we crash before
1014 * truncate finishes
1015 */
1016 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1017 ext4_orphan_add(handle, inode);
1018
1019 ext4_journal_stop(handle);
1020 if (pos + len > inode->i_size) {
1021 ext4_truncate_failed_write(inode);
1022 /*
1023 * If truncate failed early the inode might
1024 * still be on the orphan list; we need to
1025 * make sure the inode is removed from the
1026 * orphan list in that case.
1027 */
1028 if (inode->i_nlink)
1029 ext4_orphan_del(NULL, inode);
1030 }
1031
1032 if (ret == -ENOSPC &&
1033 ext4_should_retry_alloc(inode->i_sb, &retries))
1034 goto retry_journal;
1035 page_cache_release(page);
1036 return ret;
1037 }
1038 *pagep = page;
1039 return ret;
1040}
1041
1042/* For write_end() in data=journal mode */
1043static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1044{
1045 int ret;
1046 if (!buffer_mapped(bh) || buffer_freed(bh))
1047 return 0;
1048 set_buffer_uptodate(bh);
1049 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1050 clear_buffer_meta(bh);
1051 clear_buffer_prio(bh);
1052 return ret;
1053}
1054
1055/*
1056 * We need to pick up the new inode size which generic_commit_write gave us
1057 * `file' can be NULL - eg, when called from page_symlink().
1058 *
1059 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1060 * buffers are managed internally.
1061 */
1062static int ext4_write_end(struct file *file,
1063 struct address_space *mapping,
1064 loff_t pos, unsigned len, unsigned copied,
1065 struct page *page, void *fsdata)
1066{
1067 handle_t *handle = ext4_journal_current_handle();
1068 struct inode *inode = mapping->host;
1069 int ret = 0, ret2;
1070 int i_size_changed = 0;
1071
1072 trace_ext4_write_end(inode, pos, len, copied);
1073 if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE)) {
1074 ret = ext4_jbd2_file_inode(handle, inode);
1075 if (ret) {
1076 unlock_page(page);
1077 page_cache_release(page);
1078 goto errout;
1079 }
1080 }
1081
1082 if (ext4_has_inline_data(inode)) {
1083 ret = ext4_write_inline_data_end(inode, pos, len,
1084 copied, page);
1085 if (ret < 0)
1086 goto errout;
1087 copied = ret;
1088 } else
1089 copied = block_write_end(file, mapping, pos,
1090 len, copied, page, fsdata);
1091
1092 /*
1093 * No need to use i_size_read() here, the i_size
1094 * cannot change under us because we hole i_mutex.
1095 *
1096 * But it's important to update i_size while still holding page lock:
1097 * page writeout could otherwise come in and zero beyond i_size.
1098 */
1099 if (pos + copied > inode->i_size) {
1100 i_size_write(inode, pos + copied);
1101 i_size_changed = 1;
1102 }
1103
1104 if (pos + copied > EXT4_I(inode)->i_disksize) {
1105 /* We need to mark inode dirty even if
1106 * new_i_size is less that inode->i_size
1107 * but greater than i_disksize. (hint delalloc)
1108 */
1109 ext4_update_i_disksize(inode, (pos + copied));
1110 i_size_changed = 1;
1111 }
1112 unlock_page(page);
1113 page_cache_release(page);
1114
1115 /*
1116 * Don't mark the inode dirty under page lock. First, it unnecessarily
1117 * makes the holding time of page lock longer. Second, it forces lock
1118 * ordering of page lock and transaction start for journaling
1119 * filesystems.
1120 */
1121 if (i_size_changed)
1122 ext4_mark_inode_dirty(handle, inode);
1123
1124 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1125 /* if we have allocated more blocks and copied
1126 * less. We will have blocks allocated outside
1127 * inode->i_size. So truncate them
1128 */
1129 ext4_orphan_add(handle, inode);
1130errout:
1131 ret2 = ext4_journal_stop(handle);
1132 if (!ret)
1133 ret = ret2;
1134
1135 if (pos + len > inode->i_size) {
1136 ext4_truncate_failed_write(inode);
1137 /*
1138 * If truncate failed early the inode might still be
1139 * on the orphan list; we need to make sure the inode
1140 * is removed from the orphan list in that case.
1141 */
1142 if (inode->i_nlink)
1143 ext4_orphan_del(NULL, inode);
1144 }
1145
1146 return ret ? ret : copied;
1147}
1148
1149static int ext4_journalled_write_end(struct file *file,
1150 struct address_space *mapping,
1151 loff_t pos, unsigned len, unsigned copied,
1152 struct page *page, void *fsdata)
1153{
1154 handle_t *handle = ext4_journal_current_handle();
1155 struct inode *inode = mapping->host;
1156 int ret = 0, ret2;
1157 int partial = 0;
1158 unsigned from, to;
1159 loff_t new_i_size;
1160
1161 trace_ext4_journalled_write_end(inode, pos, len, copied);
1162 from = pos & (PAGE_CACHE_SIZE - 1);
1163 to = from + len;
1164
1165 BUG_ON(!ext4_handle_valid(handle));
1166
1167 if (ext4_has_inline_data(inode))
1168 copied = ext4_write_inline_data_end(inode, pos, len,
1169 copied, page);
1170 else {
1171 if (copied < len) {
1172 if (!PageUptodate(page))
1173 copied = 0;
1174 page_zero_new_buffers(page, from+copied, to);
1175 }
1176
1177 ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
1178 to, &partial, write_end_fn);
1179 if (!partial)
1180 SetPageUptodate(page);
1181 }
1182 new_i_size = pos + copied;
1183 if (new_i_size > inode->i_size)
1184 i_size_write(inode, pos+copied);
1185 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1186 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1187 if (new_i_size > EXT4_I(inode)->i_disksize) {
1188 ext4_update_i_disksize(inode, new_i_size);
1189 ret2 = ext4_mark_inode_dirty(handle, inode);
1190 if (!ret)
1191 ret = ret2;
1192 }
1193
1194 unlock_page(page);
1195 page_cache_release(page);
1196 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1197 /* if we have allocated more blocks and copied
1198 * less. We will have blocks allocated outside
1199 * inode->i_size. So truncate them
1200 */
1201 ext4_orphan_add(handle, inode);
1202
1203 ret2 = ext4_journal_stop(handle);
1204 if (!ret)
1205 ret = ret2;
1206 if (pos + len > inode->i_size) {
1207 ext4_truncate_failed_write(inode);
1208 /*
1209 * If truncate failed early the inode might still be
1210 * on the orphan list; we need to make sure the inode
1211 * is removed from the orphan list in that case.
1212 */
1213 if (inode->i_nlink)
1214 ext4_orphan_del(NULL, inode);
1215 }
1216
1217 return ret ? ret : copied;
1218}
1219
1220/*
1221 * Reserve a metadata for a single block located at lblock
1222 */
1223static int ext4_da_reserve_metadata(struct inode *inode, ext4_lblk_t lblock)
1224{
1225 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1226 struct ext4_inode_info *ei = EXT4_I(inode);
1227 unsigned int md_needed;
1228 ext4_lblk_t save_last_lblock;
1229 int save_len;
1230
1231 /*
1232 * recalculate the amount of metadata blocks to reserve
1233 * in order to allocate nrblocks
1234 * worse case is one extent per block
1235 */
1236 spin_lock(&ei->i_block_reservation_lock);
1237 /*
1238 * ext4_calc_metadata_amount() has side effects, which we have
1239 * to be prepared undo if we fail to claim space.
1240 */
1241 save_len = ei->i_da_metadata_calc_len;
1242 save_last_lblock = ei->i_da_metadata_calc_last_lblock;
1243 md_needed = EXT4_NUM_B2C(sbi,
1244 ext4_calc_metadata_amount(inode, lblock));
1245 trace_ext4_da_reserve_space(inode, md_needed);
1246
1247 /*
1248 * We do still charge estimated metadata to the sb though;
1249 * we cannot afford to run out of free blocks.
1250 */
1251 if (ext4_claim_free_clusters(sbi, md_needed, 0)) {
1252 ei->i_da_metadata_calc_len = save_len;
1253 ei->i_da_metadata_calc_last_lblock = save_last_lblock;
1254 spin_unlock(&ei->i_block_reservation_lock);
1255 return -ENOSPC;
1256 }
1257 ei->i_reserved_meta_blocks += md_needed;
1258 spin_unlock(&ei->i_block_reservation_lock);
1259
1260 return 0; /* success */
1261}
1262
1263/*
1264 * Reserve a single cluster located at lblock
1265 */
1266static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock)
1267{
1268 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1269 struct ext4_inode_info *ei = EXT4_I(inode);
1270 unsigned int md_needed;
1271 int ret;
1272 ext4_lblk_t save_last_lblock;
1273 int save_len;
1274
1275 /*
1276 * We will charge metadata quota at writeout time; this saves
1277 * us from metadata over-estimation, though we may go over by
1278 * a small amount in the end. Here we just reserve for data.
1279 */
1280 ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1281 if (ret)
1282 return ret;
1283
1284 /*
1285 * recalculate the amount of metadata blocks to reserve
1286 * in order to allocate nrblocks
1287 * worse case is one extent per block
1288 */
1289 spin_lock(&ei->i_block_reservation_lock);
1290 /*
1291 * ext4_calc_metadata_amount() has side effects, which we have
1292 * to be prepared undo if we fail to claim space.
1293 */
1294 save_len = ei->i_da_metadata_calc_len;
1295 save_last_lblock = ei->i_da_metadata_calc_last_lblock;
1296 md_needed = EXT4_NUM_B2C(sbi,
1297 ext4_calc_metadata_amount(inode, lblock));
1298 trace_ext4_da_reserve_space(inode, md_needed);
1299
1300 /*
1301 * We do still charge estimated metadata to the sb though;
1302 * we cannot afford to run out of free blocks.
1303 */
1304 if (ext4_claim_free_clusters(sbi, md_needed + 1, 0)) {
1305 ei->i_da_metadata_calc_len = save_len;
1306 ei->i_da_metadata_calc_last_lblock = save_last_lblock;
1307 spin_unlock(&ei->i_block_reservation_lock);
1308 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1309 return -ENOSPC;
1310 }
1311 ei->i_reserved_data_blocks++;
1312 ei->i_reserved_meta_blocks += md_needed;
1313 spin_unlock(&ei->i_block_reservation_lock);
1314
1315 return 0; /* success */
1316}
1317
1318static void ext4_da_release_space(struct inode *inode, int to_free)
1319{
1320 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1321 struct ext4_inode_info *ei = EXT4_I(inode);
1322
1323 if (!to_free)
1324 return; /* Nothing to release, exit */
1325
1326 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1327
1328 trace_ext4_da_release_space(inode, to_free);
1329 if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1330 /*
1331 * if there aren't enough reserved blocks, then the
1332 * counter is messed up somewhere. Since this
1333 * function is called from invalidate page, it's
1334 * harmless to return without any action.
1335 */
1336 ext4_warning(inode->i_sb, "ext4_da_release_space: "
1337 "ino %lu, to_free %d with only %d reserved "
1338 "data blocks", inode->i_ino, to_free,
1339 ei->i_reserved_data_blocks);
1340 WARN_ON(1);
1341 to_free = ei->i_reserved_data_blocks;
1342 }
1343 ei->i_reserved_data_blocks -= to_free;
1344
1345 if (ei->i_reserved_data_blocks == 0) {
1346 /*
1347 * We can release all of the reserved metadata blocks
1348 * only when we have written all of the delayed
1349 * allocation blocks.
1350 * Note that in case of bigalloc, i_reserved_meta_blocks,
1351 * i_reserved_data_blocks, etc. refer to number of clusters.
1352 */
1353 percpu_counter_sub(&sbi->s_dirtyclusters_counter,
1354 ei->i_reserved_meta_blocks);
1355 ei->i_reserved_meta_blocks = 0;
1356 ei->i_da_metadata_calc_len = 0;
1357 }
1358
1359 /* update fs dirty data blocks counter */
1360 percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1361
1362 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1363
1364 dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1365}
1366
1367static void ext4_da_page_release_reservation(struct page *page,
1368 unsigned int offset,
1369 unsigned int length)
1370{
1371 int to_release = 0;
1372 struct buffer_head *head, *bh;
1373 unsigned int curr_off = 0;
1374 struct inode *inode = page->mapping->host;
1375 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1376 unsigned int stop = offset + length;
1377 int num_clusters;
1378 ext4_fsblk_t lblk;
1379
1380 BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
1381
1382 head = page_buffers(page);
1383 bh = head;
1384 do {
1385 unsigned int next_off = curr_off + bh->b_size;
1386
1387 if (next_off > stop)
1388 break;
1389
1390 if ((offset <= curr_off) && (buffer_delay(bh))) {
1391 to_release++;
1392 clear_buffer_delay(bh);
1393 }
1394 curr_off = next_off;
1395 } while ((bh = bh->b_this_page) != head);
1396
1397 if (to_release) {
1398 lblk = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1399 ext4_es_remove_extent(inode, lblk, to_release);
1400 }
1401
1402 /* If we have released all the blocks belonging to a cluster, then we
1403 * need to release the reserved space for that cluster. */
1404 num_clusters = EXT4_NUM_B2C(sbi, to_release);
1405 while (num_clusters > 0) {
1406 lblk = (page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits)) +
1407 ((num_clusters - 1) << sbi->s_cluster_bits);
1408 if (sbi->s_cluster_ratio == 1 ||
1409 !ext4_find_delalloc_cluster(inode, lblk))
1410 ext4_da_release_space(inode, 1);
1411
1412 num_clusters--;
1413 }
1414}
1415
1416/*
1417 * Delayed allocation stuff
1418 */
1419
1420struct mpage_da_data {
1421 struct inode *inode;
1422 struct writeback_control *wbc;
1423
1424 pgoff_t first_page; /* The first page to write */
1425 pgoff_t next_page; /* Current page to examine */
1426 pgoff_t last_page; /* Last page to examine */
1427 /*
1428 * Extent to map - this can be after first_page because that can be
1429 * fully mapped. We somewhat abuse m_flags to store whether the extent
1430 * is delalloc or unwritten.
1431 */
1432 struct ext4_map_blocks map;
1433 struct ext4_io_submit io_submit; /* IO submission data */
1434};
1435
1436static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1437 bool invalidate)
1438{
1439 int nr_pages, i;
1440 pgoff_t index, end;
1441 struct pagevec pvec;
1442 struct inode *inode = mpd->inode;
1443 struct address_space *mapping = inode->i_mapping;
1444
1445 /* This is necessary when next_page == 0. */
1446 if (mpd->first_page >= mpd->next_page)
1447 return;
1448
1449 index = mpd->first_page;
1450 end = mpd->next_page - 1;
1451 if (invalidate) {
1452 ext4_lblk_t start, last;
1453 start = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1454 last = end << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1455 ext4_es_remove_extent(inode, start, last - start + 1);
1456 }
1457
1458 pagevec_init(&pvec, 0);
1459 while (index <= end) {
1460 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1461 if (nr_pages == 0)
1462 break;
1463 for (i = 0; i < nr_pages; i++) {
1464 struct page *page = pvec.pages[i];
1465 if (page->index > end)
1466 break;
1467 BUG_ON(!PageLocked(page));
1468 BUG_ON(PageWriteback(page));
1469 if (invalidate) {
1470 block_invalidatepage(page, 0, PAGE_CACHE_SIZE);
1471 ClearPageUptodate(page);
1472 }
1473 unlock_page(page);
1474 }
1475 index = pvec.pages[nr_pages - 1]->index + 1;
1476 pagevec_release(&pvec);
1477 }
1478}
1479
1480static void ext4_print_free_blocks(struct inode *inode)
1481{
1482 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1483 struct super_block *sb = inode->i_sb;
1484 struct ext4_inode_info *ei = EXT4_I(inode);
1485
1486 ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1487 EXT4_C2B(EXT4_SB(inode->i_sb),
1488 ext4_count_free_clusters(sb)));
1489 ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1490 ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1491 (long long) EXT4_C2B(EXT4_SB(sb),
1492 percpu_counter_sum(&sbi->s_freeclusters_counter)));
1493 ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1494 (long long) EXT4_C2B(EXT4_SB(sb),
1495 percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1496 ext4_msg(sb, KERN_CRIT, "Block reservation details");
1497 ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1498 ei->i_reserved_data_blocks);
1499 ext4_msg(sb, KERN_CRIT, "i_reserved_meta_blocks=%u",
1500 ei->i_reserved_meta_blocks);
1501 ext4_msg(sb, KERN_CRIT, "i_allocated_meta_blocks=%u",
1502 ei->i_allocated_meta_blocks);
1503 return;
1504}
1505
1506static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1507{
1508 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1509}
1510
1511/*
1512 * This function is grabs code from the very beginning of
1513 * ext4_map_blocks, but assumes that the caller is from delayed write
1514 * time. This function looks up the requested blocks and sets the
1515 * buffer delay bit under the protection of i_data_sem.
1516 */
1517static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1518 struct ext4_map_blocks *map,
1519 struct buffer_head *bh)
1520{
1521 struct extent_status es;
1522 int retval;
1523 sector_t invalid_block = ~((sector_t) 0xffff);
1524#ifdef ES_AGGRESSIVE_TEST
1525 struct ext4_map_blocks orig_map;
1526
1527 memcpy(&orig_map, map, sizeof(*map));
1528#endif
1529
1530 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1531 invalid_block = ~0;
1532
1533 map->m_flags = 0;
1534 ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
1535 "logical block %lu\n", inode->i_ino, map->m_len,
1536 (unsigned long) map->m_lblk);
1537
1538 /* Lookup extent status tree firstly */
1539 if (ext4_es_lookup_extent(inode, iblock, &es)) {
1540 ext4_es_lru_add(inode);
1541 if (ext4_es_is_hole(&es)) {
1542 retval = 0;
1543 down_read((&EXT4_I(inode)->i_data_sem));
1544 goto add_delayed;
1545 }
1546
1547 /*
1548 * Delayed extent could be allocated by fallocate.
1549 * So we need to check it.
1550 */
1551 if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1552 map_bh(bh, inode->i_sb, invalid_block);
1553 set_buffer_new(bh);
1554 set_buffer_delay(bh);
1555 return 0;
1556 }
1557
1558 map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1559 retval = es.es_len - (iblock - es.es_lblk);
1560 if (retval > map->m_len)
1561 retval = map->m_len;
1562 map->m_len = retval;
1563 if (ext4_es_is_written(&es))
1564 map->m_flags |= EXT4_MAP_MAPPED;
1565 else if (ext4_es_is_unwritten(&es))
1566 map->m_flags |= EXT4_MAP_UNWRITTEN;
1567 else
1568 BUG_ON(1);
1569
1570#ifdef ES_AGGRESSIVE_TEST
1571 ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1572#endif
1573 return retval;
1574 }
1575
1576 /*
1577 * Try to see if we can get the block without requesting a new
1578 * file system block.
1579 */
1580 down_read((&EXT4_I(inode)->i_data_sem));
1581 if (ext4_has_inline_data(inode)) {
1582 /*
1583 * We will soon create blocks for this page, and let
1584 * us pretend as if the blocks aren't allocated yet.
1585 * In case of clusters, we have to handle the work
1586 * of mapping from cluster so that the reserved space
1587 * is calculated properly.
1588 */
1589 if ((EXT4_SB(inode->i_sb)->s_cluster_ratio > 1) &&
1590 ext4_find_delalloc_cluster(inode, map->m_lblk))
1591 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
1592 retval = 0;
1593 } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1594 retval = ext4_ext_map_blocks(NULL, inode, map,
1595 EXT4_GET_BLOCKS_NO_PUT_HOLE);
1596 else
1597 retval = ext4_ind_map_blocks(NULL, inode, map,
1598 EXT4_GET_BLOCKS_NO_PUT_HOLE);
1599
1600add_delayed:
1601 if (retval == 0) {
1602 int ret;
1603 /*
1604 * XXX: __block_prepare_write() unmaps passed block,
1605 * is it OK?
1606 */
1607 /*
1608 * If the block was allocated from previously allocated cluster,
1609 * then we don't need to reserve it again. However we still need
1610 * to reserve metadata for every block we're going to write.
1611 */
1612 if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) {
1613 ret = ext4_da_reserve_space(inode, iblock);
1614 if (ret) {
1615 /* not enough space to reserve */
1616 retval = ret;
1617 goto out_unlock;
1618 }
1619 } else {
1620 ret = ext4_da_reserve_metadata(inode, iblock);
1621 if (ret) {
1622 /* not enough space to reserve */
1623 retval = ret;
1624 goto out_unlock;
1625 }
1626 }
1627
1628 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1629 ~0, EXTENT_STATUS_DELAYED);
1630 if (ret) {
1631 retval = ret;
1632 goto out_unlock;
1633 }
1634
1635 /* Clear EXT4_MAP_FROM_CLUSTER flag since its purpose is served
1636 * and it should not appear on the bh->b_state.
1637 */
1638 map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
1639
1640 map_bh(bh, inode->i_sb, invalid_block);
1641 set_buffer_new(bh);
1642 set_buffer_delay(bh);
1643 } else if (retval > 0) {
1644 int ret;
1645 unsigned int status;
1646
1647 if (unlikely(retval != map->m_len)) {
1648 ext4_warning(inode->i_sb,
1649 "ES len assertion failed for inode "
1650 "%lu: retval %d != map->m_len %d",
1651 inode->i_ino, retval, map->m_len);
1652 WARN_ON(1);
1653 }
1654
1655 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1656 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1657 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1658 map->m_pblk, status);
1659 if (ret != 0)
1660 retval = ret;
1661 }
1662
1663out_unlock:
1664 up_read((&EXT4_I(inode)->i_data_sem));
1665
1666 return retval;
1667}
1668
1669/*
1670 * This is a special get_blocks_t callback which is used by
1671 * ext4_da_write_begin(). It will either return mapped block or
1672 * reserve space for a single block.
1673 *
1674 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1675 * We also have b_blocknr = -1 and b_bdev initialized properly
1676 *
1677 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1678 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1679 * initialized properly.
1680 */
1681int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1682 struct buffer_head *bh, int create)
1683{
1684 struct ext4_map_blocks map;
1685 int ret = 0;
1686
1687 BUG_ON(create == 0);
1688 BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1689
1690 map.m_lblk = iblock;
1691 map.m_len = 1;
1692
1693 /*
1694 * first, we need to know whether the block is allocated already
1695 * preallocated blocks are unmapped but should treated
1696 * the same as allocated blocks.
1697 */
1698 ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1699 if (ret <= 0)
1700 return ret;
1701
1702 map_bh(bh, inode->i_sb, map.m_pblk);
1703 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
1704
1705 if (buffer_unwritten(bh)) {
1706 /* A delayed write to unwritten bh should be marked
1707 * new and mapped. Mapped ensures that we don't do
1708 * get_block multiple times when we write to the same
1709 * offset and new ensures that we do proper zero out
1710 * for partial write.
1711 */
1712 set_buffer_new(bh);
1713 set_buffer_mapped(bh);
1714 }
1715 return 0;
1716}
1717
1718static int bget_one(handle_t *handle, struct buffer_head *bh)
1719{
1720 get_bh(bh);
1721 return 0;
1722}
1723
1724static int bput_one(handle_t *handle, struct buffer_head *bh)
1725{
1726 put_bh(bh);
1727 return 0;
1728}
1729
1730static int __ext4_journalled_writepage(struct page *page,
1731 unsigned int len)
1732{
1733 struct address_space *mapping = page->mapping;
1734 struct inode *inode = mapping->host;
1735 struct buffer_head *page_bufs = NULL;
1736 handle_t *handle = NULL;
1737 int ret = 0, err = 0;
1738 int inline_data = ext4_has_inline_data(inode);
1739 struct buffer_head *inode_bh = NULL;
1740
1741 ClearPageChecked(page);
1742
1743 if (inline_data) {
1744 BUG_ON(page->index != 0);
1745 BUG_ON(len > ext4_get_max_inline_size(inode));
1746 inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1747 if (inode_bh == NULL)
1748 goto out;
1749 } else {
1750 page_bufs = page_buffers(page);
1751 if (!page_bufs) {
1752 BUG();
1753 goto out;
1754 }
1755 ext4_walk_page_buffers(handle, page_bufs, 0, len,
1756 NULL, bget_one);
1757 }
1758 /* As soon as we unlock the page, it can go away, but we have
1759 * references to buffers so we are safe */
1760 unlock_page(page);
1761
1762 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1763 ext4_writepage_trans_blocks(inode));
1764 if (IS_ERR(handle)) {
1765 ret = PTR_ERR(handle);
1766 goto out;
1767 }
1768
1769 BUG_ON(!ext4_handle_valid(handle));
1770
1771 if (inline_data) {
1772 ret = ext4_journal_get_write_access(handle, inode_bh);
1773
1774 err = ext4_handle_dirty_metadata(handle, inode, inode_bh);
1775
1776 } else {
1777 ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1778 do_journal_get_write_access);
1779
1780 err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1781 write_end_fn);
1782 }
1783 if (ret == 0)
1784 ret = err;
1785 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1786 err = ext4_journal_stop(handle);
1787 if (!ret)
1788 ret = err;
1789
1790 if (!ext4_has_inline_data(inode))
1791 ext4_walk_page_buffers(NULL, page_bufs, 0, len,
1792 NULL, bput_one);
1793 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1794out:
1795 brelse(inode_bh);
1796 return ret;
1797}
1798
1799/*
1800 * Note that we don't need to start a transaction unless we're journaling data
1801 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1802 * need to file the inode to the transaction's list in ordered mode because if
1803 * we are writing back data added by write(), the inode is already there and if
1804 * we are writing back data modified via mmap(), no one guarantees in which
1805 * transaction the data will hit the disk. In case we are journaling data, we
1806 * cannot start transaction directly because transaction start ranks above page
1807 * lock so we have to do some magic.
1808 *
1809 * This function can get called via...
1810 * - ext4_writepages after taking page lock (have journal handle)
1811 * - journal_submit_inode_data_buffers (no journal handle)
1812 * - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1813 * - grab_page_cache when doing write_begin (have journal handle)
1814 *
1815 * We don't do any block allocation in this function. If we have page with
1816 * multiple blocks we need to write those buffer_heads that are mapped. This
1817 * is important for mmaped based write. So if we do with blocksize 1K
1818 * truncate(f, 1024);
1819 * a = mmap(f, 0, 4096);
1820 * a[0] = 'a';
1821 * truncate(f, 4096);
1822 * we have in the page first buffer_head mapped via page_mkwrite call back
1823 * but other buffer_heads would be unmapped but dirty (dirty done via the
1824 * do_wp_page). So writepage should write the first block. If we modify
1825 * the mmap area beyond 1024 we will again get a page_fault and the
1826 * page_mkwrite callback will do the block allocation and mark the
1827 * buffer_heads mapped.
1828 *
1829 * We redirty the page if we have any buffer_heads that is either delay or
1830 * unwritten in the page.
1831 *
1832 * We can get recursively called as show below.
1833 *
1834 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1835 * ext4_writepage()
1836 *
1837 * But since we don't do any block allocation we should not deadlock.
1838 * Page also have the dirty flag cleared so we don't get recurive page_lock.
1839 */
1840static int ext4_writepage(struct page *page,
1841 struct writeback_control *wbc)
1842{
1843 int ret = 0;
1844 loff_t size;
1845 unsigned int len;
1846 struct buffer_head *page_bufs = NULL;
1847 struct inode *inode = page->mapping->host;
1848 struct ext4_io_submit io_submit;
1849
1850 trace_ext4_writepage(page);
1851 size = i_size_read(inode);
1852 if (page->index == size >> PAGE_CACHE_SHIFT)
1853 len = size & ~PAGE_CACHE_MASK;
1854 else
1855 len = PAGE_CACHE_SIZE;
1856
1857 page_bufs = page_buffers(page);
1858 /*
1859 * We cannot do block allocation or other extent handling in this
1860 * function. If there are buffers needing that, we have to redirty
1861 * the page. But we may reach here when we do a journal commit via
1862 * journal_submit_inode_data_buffers() and in that case we must write
1863 * allocated buffers to achieve data=ordered mode guarantees.
1864 */
1865 if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
1866 ext4_bh_delay_or_unwritten)) {
1867 redirty_page_for_writepage(wbc, page);
1868 if (current->flags & PF_MEMALLOC) {
1869 /*
1870 * For memory cleaning there's no point in writing only
1871 * some buffers. So just bail out. Warn if we came here
1872 * from direct reclaim.
1873 */
1874 WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
1875 == PF_MEMALLOC);
1876 unlock_page(page);
1877 return 0;
1878 }
1879 }
1880
1881 if (PageChecked(page) && ext4_should_journal_data(inode))
1882 /*
1883 * It's mmapped pagecache. Add buffers and journal it. There
1884 * doesn't seem much point in redirtying the page here.
1885 */
1886 return __ext4_journalled_writepage(page, len);
1887
1888 ext4_io_submit_init(&io_submit, wbc);
1889 io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
1890 if (!io_submit.io_end) {
1891 redirty_page_for_writepage(wbc, page);
1892 unlock_page(page);
1893 return -ENOMEM;
1894 }
1895 ret = ext4_bio_write_page(&io_submit, page, len, wbc);
1896 ext4_io_submit(&io_submit);
1897 /* Drop io_end reference we got from init */
1898 ext4_put_io_end_defer(io_submit.io_end);
1899 return ret;
1900}
1901
1902static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
1903{
1904 int len;
1905 loff_t size = i_size_read(mpd->inode);
1906 int err;
1907
1908 BUG_ON(page->index != mpd->first_page);
1909 if (page->index == size >> PAGE_CACHE_SHIFT)
1910 len = size & ~PAGE_CACHE_MASK;
1911 else
1912 len = PAGE_CACHE_SIZE;
1913 clear_page_dirty_for_io(page);
1914 err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc);
1915 if (!err)
1916 mpd->wbc->nr_to_write--;
1917 mpd->first_page++;
1918
1919 return err;
1920}
1921
1922#define BH_FLAGS ((1 << BH_Unwritten) | (1 << BH_Delay))
1923
1924/*
1925 * mballoc gives us at most this number of blocks...
1926 * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
1927 * The rest of mballoc seems to handle chunks up to full group size.
1928 */
1929#define MAX_WRITEPAGES_EXTENT_LEN 2048
1930
1931/*
1932 * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
1933 *
1934 * @mpd - extent of blocks
1935 * @lblk - logical number of the block in the file
1936 * @bh - buffer head we want to add to the extent
1937 *
1938 * The function is used to collect contig. blocks in the same state. If the
1939 * buffer doesn't require mapping for writeback and we haven't started the
1940 * extent of buffers to map yet, the function returns 'true' immediately - the
1941 * caller can write the buffer right away. Otherwise the function returns true
1942 * if the block has been added to the extent, false if the block couldn't be
1943 * added.
1944 */
1945static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
1946 struct buffer_head *bh)
1947{
1948 struct ext4_map_blocks *map = &mpd->map;
1949
1950 /* Buffer that doesn't need mapping for writeback? */
1951 if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
1952 (!buffer_delay(bh) && !buffer_unwritten(bh))) {
1953 /* So far no extent to map => we write the buffer right away */
1954 if (map->m_len == 0)
1955 return true;
1956 return false;
1957 }
1958
1959 /* First block in the extent? */
1960 if (map->m_len == 0) {
1961 map->m_lblk = lblk;
1962 map->m_len = 1;
1963 map->m_flags = bh->b_state & BH_FLAGS;
1964 return true;
1965 }
1966
1967 /* Don't go larger than mballoc is willing to allocate */
1968 if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
1969 return false;
1970
1971 /* Can we merge the block to our big extent? */
1972 if (lblk == map->m_lblk + map->m_len &&
1973 (bh->b_state & BH_FLAGS) == map->m_flags) {
1974 map->m_len++;
1975 return true;
1976 }
1977 return false;
1978}
1979
1980/*
1981 * mpage_process_page_bufs - submit page buffers for IO or add them to extent
1982 *
1983 * @mpd - extent of blocks for mapping
1984 * @head - the first buffer in the page
1985 * @bh - buffer we should start processing from
1986 * @lblk - logical number of the block in the file corresponding to @bh
1987 *
1988 * Walk through page buffers from @bh upto @head (exclusive) and either submit
1989 * the page for IO if all buffers in this page were mapped and there's no
1990 * accumulated extent of buffers to map or add buffers in the page to the
1991 * extent of buffers to map. The function returns 1 if the caller can continue
1992 * by processing the next page, 0 if it should stop adding buffers to the
1993 * extent to map because we cannot extend it anymore. It can also return value
1994 * < 0 in case of error during IO submission.
1995 */
1996static int mpage_process_page_bufs(struct mpage_da_data *mpd,
1997 struct buffer_head *head,
1998 struct buffer_head *bh,
1999 ext4_lblk_t lblk)
2000{
2001 struct inode *inode = mpd->inode;
2002 int err;
2003 ext4_lblk_t blocks = (i_size_read(inode) + (1 << inode->i_blkbits) - 1)
2004 >> inode->i_blkbits;
2005
2006 do {
2007 BUG_ON(buffer_locked(bh));
2008
2009 if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2010 /* Found extent to map? */
2011 if (mpd->map.m_len)
2012 return 0;
2013 /* Everything mapped so far and we hit EOF */
2014 break;
2015 }
2016 } while (lblk++, (bh = bh->b_this_page) != head);
2017 /* So far everything mapped? Submit the page for IO. */
2018 if (mpd->map.m_len == 0) {
2019 err = mpage_submit_page(mpd, head->b_page);
2020 if (err < 0)
2021 return err;
2022 }
2023 return lblk < blocks;
2024}
2025
2026/*
2027 * mpage_map_buffers - update buffers corresponding to changed extent and
2028 * submit fully mapped pages for IO
2029 *
2030 * @mpd - description of extent to map, on return next extent to map
2031 *
2032 * Scan buffers corresponding to changed extent (we expect corresponding pages
2033 * to be already locked) and update buffer state according to new extent state.
2034 * We map delalloc buffers to their physical location, clear unwritten bits,
2035 * and mark buffers as uninit when we perform writes to uninitialized extents
2036 * and do extent conversion after IO is finished. If the last page is not fully
2037 * mapped, we update @map to the next extent in the last page that needs
2038 * mapping. Otherwise we submit the page for IO.
2039 */
2040static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2041{
2042 struct pagevec pvec;
2043 int nr_pages, i;
2044 struct inode *inode = mpd->inode;
2045 struct buffer_head *head, *bh;
2046 int bpp_bits = PAGE_CACHE_SHIFT - inode->i_blkbits;
2047 pgoff_t start, end;
2048 ext4_lblk_t lblk;
2049 sector_t pblock;
2050 int err;
2051
2052 start = mpd->map.m_lblk >> bpp_bits;
2053 end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2054 lblk = start << bpp_bits;
2055 pblock = mpd->map.m_pblk;
2056
2057 pagevec_init(&pvec, 0);
2058 while (start <= end) {
2059 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, start,
2060 PAGEVEC_SIZE);
2061 if (nr_pages == 0)
2062 break;
2063 for (i = 0; i < nr_pages; i++) {
2064 struct page *page = pvec.pages[i];
2065
2066 if (page->index > end)
2067 break;
2068 /* Up to 'end' pages must be contiguous */
2069 BUG_ON(page->index != start);
2070 bh = head = page_buffers(page);
2071 do {
2072 if (lblk < mpd->map.m_lblk)
2073 continue;
2074 if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2075 /*
2076 * Buffer after end of mapped extent.
2077 * Find next buffer in the page to map.
2078 */
2079 mpd->map.m_len = 0;
2080 mpd->map.m_flags = 0;
2081 /*
2082 * FIXME: If dioread_nolock supports
2083 * blocksize < pagesize, we need to make
2084 * sure we add size mapped so far to
2085 * io_end->size as the following call
2086 * can submit the page for IO.
2087 */
2088 err = mpage_process_page_bufs(mpd, head,
2089 bh, lblk);
2090 pagevec_release(&pvec);
2091 if (err > 0)
2092 err = 0;
2093 return err;
2094 }
2095 if (buffer_delay(bh)) {
2096 clear_buffer_delay(bh);
2097 bh->b_blocknr = pblock++;
2098 }
2099 clear_buffer_unwritten(bh);
2100 } while (lblk++, (bh = bh->b_this_page) != head);
2101
2102 /*
2103 * FIXME: This is going to break if dioread_nolock
2104 * supports blocksize < pagesize as we will try to
2105 * convert potentially unmapped parts of inode.
2106 */
2107 mpd->io_submit.io_end->size += PAGE_CACHE_SIZE;
2108 /* Page fully mapped - let IO run! */
2109 err = mpage_submit_page(mpd, page);
2110 if (err < 0) {
2111 pagevec_release(&pvec);
2112 return err;
2113 }
2114 start++;
2115 }
2116 pagevec_release(&pvec);
2117 }
2118 /* Extent fully mapped and matches with page boundary. We are done. */
2119 mpd->map.m_len = 0;
2120 mpd->map.m_flags = 0;
2121 return 0;
2122}
2123
2124static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2125{
2126 struct inode *inode = mpd->inode;
2127 struct ext4_map_blocks *map = &mpd->map;
2128 int get_blocks_flags;
2129 int err;
2130
2131 trace_ext4_da_write_pages_extent(inode, map);
2132 /*
2133 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2134 * to convert an uninitialized extent to be initialized (in the case
2135 * where we have written into one or more preallocated blocks). It is
2136 * possible that we're going to need more metadata blocks than
2137 * previously reserved. However we must not fail because we're in
2138 * writeback and there is nothing we can do about it so it might result
2139 * in data loss. So use reserved blocks to allocate metadata if
2140 * possible.
2141 *
2142 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if the blocks
2143 * in question are delalloc blocks. This affects functions in many
2144 * different parts of the allocation call path. This flag exists
2145 * primarily because we don't want to change *many* call functions, so
2146 * ext4_map_blocks() will set the EXT4_STATE_DELALLOC_RESERVED flag
2147 * once the inode's allocation semaphore is taken.
2148 */
2149 get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2150 EXT4_GET_BLOCKS_METADATA_NOFAIL;
2151 if (ext4_should_dioread_nolock(inode))
2152 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2153 if (map->m_flags & (1 << BH_Delay))
2154 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2155
2156 err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2157 if (err < 0)
2158 return err;
2159 if (map->m_flags & EXT4_MAP_UNINIT) {
2160 if (!mpd->io_submit.io_end->handle &&
2161 ext4_handle_valid(handle)) {
2162 mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2163 handle->h_rsv_handle = NULL;
2164 }
2165 ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2166 }
2167
2168 BUG_ON(map->m_len == 0);
2169 if (map->m_flags & EXT4_MAP_NEW) {
2170 struct block_device *bdev = inode->i_sb->s_bdev;
2171 int i;
2172
2173 for (i = 0; i < map->m_len; i++)
2174 unmap_underlying_metadata(bdev, map->m_pblk + i);
2175 }
2176 return 0;
2177}
2178
2179/*
2180 * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2181 * mpd->len and submit pages underlying it for IO
2182 *
2183 * @handle - handle for journal operations
2184 * @mpd - extent to map
2185 * @give_up_on_write - we set this to true iff there is a fatal error and there
2186 * is no hope of writing the data. The caller should discard
2187 * dirty pages to avoid infinite loops.
2188 *
2189 * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2190 * delayed, blocks are allocated, if it is unwritten, we may need to convert
2191 * them to initialized or split the described range from larger unwritten
2192 * extent. Note that we need not map all the described range since allocation
2193 * can return less blocks or the range is covered by more unwritten extents. We
2194 * cannot map more because we are limited by reserved transaction credits. On
2195 * the other hand we always make sure that the last touched page is fully
2196 * mapped so that it can be written out (and thus forward progress is
2197 * guaranteed). After mapping we submit all mapped pages for IO.
2198 */
2199static int mpage_map_and_submit_extent(handle_t *handle,
2200 struct mpage_da_data *mpd,
2201 bool *give_up_on_write)
2202{
2203 struct inode *inode = mpd->inode;
2204 struct ext4_map_blocks *map = &mpd->map;
2205 int err;
2206 loff_t disksize;
2207
2208 mpd->io_submit.io_end->offset =
2209 ((loff_t)map->m_lblk) << inode->i_blkbits;
2210 do {
2211 err = mpage_map_one_extent(handle, mpd);
2212 if (err < 0) {
2213 struct super_block *sb = inode->i_sb;
2214
2215 if (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
2216 goto invalidate_dirty_pages;
2217 /*
2218 * Let the uper layers retry transient errors.
2219 * In the case of ENOSPC, if ext4_count_free_blocks()
2220 * is non-zero, a commit should free up blocks.
2221 */
2222 if ((err == -ENOMEM) ||
2223 (err == -ENOSPC && ext4_count_free_clusters(sb)))
2224 return err;
2225 ext4_msg(sb, KERN_CRIT,
2226 "Delayed block allocation failed for "
2227 "inode %lu at logical offset %llu with"
2228 " max blocks %u with error %d",
2229 inode->i_ino,
2230 (unsigned long long)map->m_lblk,
2231 (unsigned)map->m_len, -err);
2232 ext4_msg(sb, KERN_CRIT,
2233 "This should not happen!! Data will "
2234 "be lost\n");
2235 if (err == -ENOSPC)
2236 ext4_print_free_blocks(inode);
2237 invalidate_dirty_pages:
2238 *give_up_on_write = true;
2239 return err;
2240 }
2241 /*
2242 * Update buffer state, submit mapped pages, and get us new
2243 * extent to map
2244 */
2245 err = mpage_map_and_submit_buffers(mpd);
2246 if (err < 0)
2247 return err;
2248 } while (map->m_len);
2249
2250 /*
2251 * Update on-disk size after IO is submitted. Races with
2252 * truncate are avoided by checking i_size under i_data_sem.
2253 */
2254 disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT;
2255 if (disksize > EXT4_I(inode)->i_disksize) {
2256 int err2;
2257 loff_t i_size;
2258
2259 down_write(&EXT4_I(inode)->i_data_sem);
2260 i_size = i_size_read(inode);
2261 if (disksize > i_size)
2262 disksize = i_size;
2263 if (disksize > EXT4_I(inode)->i_disksize)
2264 EXT4_I(inode)->i_disksize = disksize;
2265 err2 = ext4_mark_inode_dirty(handle, inode);
2266 up_write(&EXT4_I(inode)->i_data_sem);
2267 if (err2)
2268 ext4_error(inode->i_sb,
2269 "Failed to mark inode %lu dirty",
2270 inode->i_ino);
2271 if (!err)
2272 err = err2;
2273 }
2274 return err;
2275}
2276
2277/*
2278 * Calculate the total number of credits to reserve for one writepages
2279 * iteration. This is called from ext4_writepages(). We map an extent of
2280 * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2281 * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2282 * bpp - 1 blocks in bpp different extents.
2283 */
2284static int ext4_da_writepages_trans_blocks(struct inode *inode)
2285{
2286 int bpp = ext4_journal_blocks_per_page(inode);
2287
2288 return ext4_meta_trans_blocks(inode,
2289 MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2290}
2291
2292/*
2293 * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2294 * and underlying extent to map
2295 *
2296 * @mpd - where to look for pages
2297 *
2298 * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2299 * IO immediately. When we find a page which isn't mapped we start accumulating
2300 * extent of buffers underlying these pages that needs mapping (formed by
2301 * either delayed or unwritten buffers). We also lock the pages containing
2302 * these buffers. The extent found is returned in @mpd structure (starting at
2303 * mpd->lblk with length mpd->len blocks).
2304 *
2305 * Note that this function can attach bios to one io_end structure which are
2306 * neither logically nor physically contiguous. Although it may seem as an
2307 * unnecessary complication, it is actually inevitable in blocksize < pagesize
2308 * case as we need to track IO to all buffers underlying a page in one io_end.
2309 */
2310static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2311{
2312 struct address_space *mapping = mpd->inode->i_mapping;
2313 struct pagevec pvec;
2314 unsigned int nr_pages;
2315 long left = mpd->wbc->nr_to_write;
2316 pgoff_t index = mpd->first_page;
2317 pgoff_t end = mpd->last_page;
2318 int tag;
2319 int i, err = 0;
2320 int blkbits = mpd->inode->i_blkbits;
2321 ext4_lblk_t lblk;
2322 struct buffer_head *head;
2323
2324 if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2325 tag = PAGECACHE_TAG_TOWRITE;
2326 else
2327 tag = PAGECACHE_TAG_DIRTY;
2328
2329 pagevec_init(&pvec, 0);
2330 mpd->map.m_len = 0;
2331 mpd->next_page = index;
2332 while (index <= end) {
2333 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2334 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
2335 if (nr_pages == 0)
2336 goto out;
2337
2338 for (i = 0; i < nr_pages; i++) {
2339 struct page *page = pvec.pages[i];
2340
2341 /*
2342 * At this point, the page may be truncated or
2343 * invalidated (changing page->mapping to NULL), or
2344 * even swizzled back from swapper_space to tmpfs file
2345 * mapping. However, page->index will not change
2346 * because we have a reference on the page.
2347 */
2348 if (page->index > end)
2349 goto out;
2350
2351 /*
2352 * Accumulated enough dirty pages? This doesn't apply
2353 * to WB_SYNC_ALL mode. For integrity sync we have to
2354 * keep going because someone may be concurrently
2355 * dirtying pages, and we might have synced a lot of
2356 * newly appeared dirty pages, but have not synced all
2357 * of the old dirty pages.
2358 */
2359 if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2360 goto out;
2361
2362 /* If we can't merge this page, we are done. */
2363 if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2364 goto out;
2365
2366 lock_page(page);
2367 /*
2368 * If the page is no longer dirty, or its mapping no
2369 * longer corresponds to inode we are writing (which
2370 * means it has been truncated or invalidated), or the
2371 * page is already under writeback and we are not doing
2372 * a data integrity writeback, skip the page
2373 */
2374 if (!PageDirty(page) ||
2375 (PageWriteback(page) &&
2376 (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2377 unlikely(page->mapping != mapping)) {
2378 unlock_page(page);
2379 continue;
2380 }
2381
2382 wait_on_page_writeback(page);
2383 BUG_ON(PageWriteback(page));
2384
2385 if (mpd->map.m_len == 0)
2386 mpd->first_page = page->index;
2387 mpd->next_page = page->index + 1;
2388 /* Add all dirty buffers to mpd */
2389 lblk = ((ext4_lblk_t)page->index) <<
2390 (PAGE_CACHE_SHIFT - blkbits);
2391 head = page_buffers(page);
2392 err = mpage_process_page_bufs(mpd, head, head, lblk);
2393 if (err <= 0)
2394 goto out;
2395 err = 0;
2396 left--;
2397 }
2398 pagevec_release(&pvec);
2399 cond_resched();
2400 }
2401 return 0;
2402out:
2403 pagevec_release(&pvec);
2404 return err;
2405}
2406
2407static int __writepage(struct page *page, struct writeback_control *wbc,
2408 void *data)
2409{
2410 struct address_space *mapping = data;
2411 int ret = ext4_writepage(page, wbc);
2412 mapping_set_error(mapping, ret);
2413 return ret;
2414}
2415
2416static int ext4_writepages(struct address_space *mapping,
2417 struct writeback_control *wbc)
2418{
2419 pgoff_t writeback_index = 0;
2420 long nr_to_write = wbc->nr_to_write;
2421 int range_whole = 0;
2422 int cycled = 1;
2423 handle_t *handle = NULL;
2424 struct mpage_da_data mpd;
2425 struct inode *inode = mapping->host;
2426 int needed_blocks, rsv_blocks = 0, ret = 0;
2427 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2428 bool done;
2429 struct blk_plug plug;
2430 bool give_up_on_write = false;
2431
2432 trace_ext4_writepages(inode, wbc);
2433
2434 /*
2435 * No pages to write? This is mainly a kludge to avoid starting
2436 * a transaction for special inodes like journal inode on last iput()
2437 * because that could violate lock ordering on umount
2438 */
2439 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2440 goto out_writepages;
2441
2442 if (ext4_should_journal_data(inode)) {
2443 struct blk_plug plug;
2444
2445 blk_start_plug(&plug);
2446 ret = write_cache_pages(mapping, wbc, __writepage, mapping);
2447 blk_finish_plug(&plug);
2448 goto out_writepages;
2449 }
2450
2451 /*
2452 * If the filesystem has aborted, it is read-only, so return
2453 * right away instead of dumping stack traces later on that
2454 * will obscure the real source of the problem. We test
2455 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2456 * the latter could be true if the filesystem is mounted
2457 * read-only, and in that case, ext4_writepages should
2458 * *never* be called, so if that ever happens, we would want
2459 * the stack trace.
2460 */
2461 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2462 ret = -EROFS;
2463 goto out_writepages;
2464 }
2465
2466 if (ext4_should_dioread_nolock(inode)) {
2467 /*
2468 * We may need to convert up to one extent per block in
2469 * the page and we may dirty the inode.
2470 */
2471 rsv_blocks = 1 + (PAGE_CACHE_SIZE >> inode->i_blkbits);
2472 }
2473
2474 /*
2475 * If we have inline data and arrive here, it means that
2476 * we will soon create the block for the 1st page, so
2477 * we'd better clear the inline data here.
2478 */
2479 if (ext4_has_inline_data(inode)) {
2480 /* Just inode will be modified... */
2481 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2482 if (IS_ERR(handle)) {
2483 ret = PTR_ERR(handle);
2484 goto out_writepages;
2485 }
2486 BUG_ON(ext4_test_inode_state(inode,
2487 EXT4_STATE_MAY_INLINE_DATA));
2488 ext4_destroy_inline_data(handle, inode);
2489 ext4_journal_stop(handle);
2490 }
2491
2492 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2493 range_whole = 1;
2494
2495 if (wbc->range_cyclic) {
2496 writeback_index = mapping->writeback_index;
2497 if (writeback_index)
2498 cycled = 0;
2499 mpd.first_page = writeback_index;
2500 mpd.last_page = -1;
2501 } else {
2502 mpd.first_page = wbc->range_start >> PAGE_CACHE_SHIFT;
2503 mpd.last_page = wbc->range_end >> PAGE_CACHE_SHIFT;
2504 }
2505
2506 mpd.inode = inode;
2507 mpd.wbc = wbc;
2508 ext4_io_submit_init(&mpd.io_submit, wbc);
2509retry:
2510 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2511 tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2512 done = false;
2513 blk_start_plug(&plug);
2514 while (!done && mpd.first_page <= mpd.last_page) {
2515 /* For each extent of pages we use new io_end */
2516 mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2517 if (!mpd.io_submit.io_end) {
2518 ret = -ENOMEM;
2519 break;
2520 }
2521
2522 /*
2523 * We have two constraints: We find one extent to map and we
2524 * must always write out whole page (makes a difference when
2525 * blocksize < pagesize) so that we don't block on IO when we
2526 * try to write out the rest of the page. Journalled mode is
2527 * not supported by delalloc.
2528 */
2529 BUG_ON(ext4_should_journal_data(inode));
2530 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2531
2532 /* start a new transaction */
2533 handle = ext4_journal_start_with_reserve(inode,
2534 EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2535 if (IS_ERR(handle)) {
2536 ret = PTR_ERR(handle);
2537 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2538 "%ld pages, ino %lu; err %d", __func__,
2539 wbc->nr_to_write, inode->i_ino, ret);
2540 /* Release allocated io_end */
2541 ext4_put_io_end(mpd.io_submit.io_end);
2542 break;
2543 }
2544
2545 trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2546 ret = mpage_prepare_extent_to_map(&mpd);
2547 if (!ret) {
2548 if (mpd.map.m_len)
2549 ret = mpage_map_and_submit_extent(handle, &mpd,
2550 &give_up_on_write);
2551 else {
2552 /*
2553 * We scanned the whole range (or exhausted
2554 * nr_to_write), submitted what was mapped and
2555 * didn't find anything needing mapping. We are
2556 * done.
2557 */
2558 done = true;
2559 }
2560 }
2561 ext4_journal_stop(handle);
2562 /* Submit prepared bio */
2563 ext4_io_submit(&mpd.io_submit);
2564 /* Unlock pages we didn't use */
2565 mpage_release_unused_pages(&mpd, give_up_on_write);
2566 /* Drop our io_end reference we got from init */
2567 ext4_put_io_end(mpd.io_submit.io_end);
2568
2569 if (ret == -ENOSPC && sbi->s_journal) {
2570 /*
2571 * Commit the transaction which would
2572 * free blocks released in the transaction
2573 * and try again
2574 */
2575 jbd2_journal_force_commit_nested(sbi->s_journal);
2576 ret = 0;
2577 continue;
2578 }
2579 /* Fatal error - ENOMEM, EIO... */
2580 if (ret)
2581 break;
2582 }
2583 blk_finish_plug(&plug);
2584 if (!ret && !cycled && wbc->nr_to_write > 0) {
2585 cycled = 1;
2586 mpd.last_page = writeback_index - 1;
2587 mpd.first_page = 0;
2588 goto retry;
2589 }
2590
2591 /* Update index */
2592 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2593 /*
2594 * Set the writeback_index so that range_cyclic
2595 * mode will write it back later
2596 */
2597 mapping->writeback_index = mpd.first_page;
2598
2599out_writepages:
2600 trace_ext4_writepages_result(inode, wbc, ret,
2601 nr_to_write - wbc->nr_to_write);
2602 return ret;
2603}
2604
2605static int ext4_nonda_switch(struct super_block *sb)
2606{
2607 s64 free_clusters, dirty_clusters;
2608 struct ext4_sb_info *sbi = EXT4_SB(sb);
2609
2610 /*
2611 * switch to non delalloc mode if we are running low
2612 * on free block. The free block accounting via percpu
2613 * counters can get slightly wrong with percpu_counter_batch getting
2614 * accumulated on each CPU without updating global counters
2615 * Delalloc need an accurate free block accounting. So switch
2616 * to non delalloc when we are near to error range.
2617 */
2618 free_clusters =
2619 percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2620 dirty_clusters =
2621 percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2622 /*
2623 * Start pushing delalloc when 1/2 of free blocks are dirty.
2624 */
2625 if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2626 try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2627
2628 if (2 * free_clusters < 3 * dirty_clusters ||
2629 free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2630 /*
2631 * free block count is less than 150% of dirty blocks
2632 * or free blocks is less than watermark
2633 */
2634 return 1;
2635 }
2636 return 0;
2637}
2638
2639static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2640 loff_t pos, unsigned len, unsigned flags,
2641 struct page **pagep, void **fsdata)
2642{
2643 int ret, retries = 0;
2644 struct page *page;
2645 pgoff_t index;
2646 struct inode *inode = mapping->host;
2647 handle_t *handle;
2648
2649 index = pos >> PAGE_CACHE_SHIFT;
2650
2651 if (ext4_nonda_switch(inode->i_sb)) {
2652 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2653 return ext4_write_begin(file, mapping, pos,
2654 len, flags, pagep, fsdata);
2655 }
2656 *fsdata = (void *)0;
2657 trace_ext4_da_write_begin(inode, pos, len, flags);
2658
2659 if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2660 ret = ext4_da_write_inline_data_begin(mapping, inode,
2661 pos, len, flags,
2662 pagep, fsdata);
2663 if (ret < 0)
2664 return ret;
2665 if (ret == 1)
2666 return 0;
2667 }
2668
2669 /*
2670 * grab_cache_page_write_begin() can take a long time if the
2671 * system is thrashing due to memory pressure, or if the page
2672 * is being written back. So grab it first before we start
2673 * the transaction handle. This also allows us to allocate
2674 * the page (if needed) without using GFP_NOFS.
2675 */
2676retry_grab:
2677 page = grab_cache_page_write_begin(mapping, index, flags);
2678 if (!page)
2679 return -ENOMEM;
2680 unlock_page(page);
2681
2682 /*
2683 * With delayed allocation, we don't log the i_disksize update
2684 * if there is delayed block allocation. But we still need
2685 * to journalling the i_disksize update if writes to the end
2686 * of file which has an already mapped buffer.
2687 */
2688retry_journal:
2689 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, 1);
2690 if (IS_ERR(handle)) {
2691 page_cache_release(page);
2692 return PTR_ERR(handle);
2693 }
2694
2695 lock_page(page);
2696 if (page->mapping != mapping) {
2697 /* The page got truncated from under us */
2698 unlock_page(page);
2699 page_cache_release(page);
2700 ext4_journal_stop(handle);
2701 goto retry_grab;
2702 }
2703 /* In case writeback began while the page was unlocked */
2704 wait_for_stable_page(page);
2705
2706 ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2707 if (ret < 0) {
2708 unlock_page(page);
2709 ext4_journal_stop(handle);
2710 /*
2711 * block_write_begin may have instantiated a few blocks
2712 * outside i_size. Trim these off again. Don't need
2713 * i_size_read because we hold i_mutex.
2714 */
2715 if (pos + len > inode->i_size)
2716 ext4_truncate_failed_write(inode);
2717
2718 if (ret == -ENOSPC &&
2719 ext4_should_retry_alloc(inode->i_sb, &retries))
2720 goto retry_journal;
2721
2722 page_cache_release(page);
2723 return ret;
2724 }
2725
2726 *pagep = page;
2727 return ret;
2728}
2729
2730/*
2731 * Check if we should update i_disksize
2732 * when write to the end of file but not require block allocation
2733 */
2734static int ext4_da_should_update_i_disksize(struct page *page,
2735 unsigned long offset)
2736{
2737 struct buffer_head *bh;
2738 struct inode *inode = page->mapping->host;
2739 unsigned int idx;
2740 int i;
2741
2742 bh = page_buffers(page);
2743 idx = offset >> inode->i_blkbits;
2744
2745 for (i = 0; i < idx; i++)
2746 bh = bh->b_this_page;
2747
2748 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2749 return 0;
2750 return 1;
2751}
2752
2753static int ext4_da_write_end(struct file *file,
2754 struct address_space *mapping,
2755 loff_t pos, unsigned len, unsigned copied,
2756 struct page *page, void *fsdata)
2757{
2758 struct inode *inode = mapping->host;
2759 int ret = 0, ret2;
2760 handle_t *handle = ext4_journal_current_handle();
2761 loff_t new_i_size;
2762 unsigned long start, end;
2763 int write_mode = (int)(unsigned long)fsdata;
2764
2765 if (write_mode == FALL_BACK_TO_NONDELALLOC)
2766 return ext4_write_end(file, mapping, pos,
2767 len, copied, page, fsdata);
2768
2769 trace_ext4_da_write_end(inode, pos, len, copied);
2770 start = pos & (PAGE_CACHE_SIZE - 1);
2771 end = start + copied - 1;
2772
2773 /*
2774 * generic_write_end() will run mark_inode_dirty() if i_size
2775 * changes. So let's piggyback the i_disksize mark_inode_dirty
2776 * into that.
2777 */
2778 new_i_size = pos + copied;
2779 if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
2780 if (ext4_has_inline_data(inode) ||
2781 ext4_da_should_update_i_disksize(page, end)) {
2782 down_write(&EXT4_I(inode)->i_data_sem);
2783 if (new_i_size > EXT4_I(inode)->i_disksize)
2784 EXT4_I(inode)->i_disksize = new_i_size;
2785 up_write(&EXT4_I(inode)->i_data_sem);
2786 /* We need to mark inode dirty even if
2787 * new_i_size is less that inode->i_size
2788 * bu greater than i_disksize.(hint delalloc)
2789 */
2790 ext4_mark_inode_dirty(handle, inode);
2791 }
2792 }
2793
2794 if (write_mode != CONVERT_INLINE_DATA &&
2795 ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
2796 ext4_has_inline_data(inode))
2797 ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
2798 page);
2799 else
2800 ret2 = generic_write_end(file, mapping, pos, len, copied,
2801 page, fsdata);
2802
2803 copied = ret2;
2804 if (ret2 < 0)
2805 ret = ret2;
2806 ret2 = ext4_journal_stop(handle);
2807 if (!ret)
2808 ret = ret2;
2809
2810 return ret ? ret : copied;
2811}
2812
2813static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
2814 unsigned int length)
2815{
2816 /*
2817 * Drop reserved blocks
2818 */
2819 BUG_ON(!PageLocked(page));
2820 if (!page_has_buffers(page))
2821 goto out;
2822
2823 ext4_da_page_release_reservation(page, offset, length);
2824
2825out:
2826 ext4_invalidatepage(page, offset, length);
2827
2828 return;
2829}
2830
2831/*
2832 * Force all delayed allocation blocks to be allocated for a given inode.
2833 */
2834int ext4_alloc_da_blocks(struct inode *inode)
2835{
2836 trace_ext4_alloc_da_blocks(inode);
2837
2838 if (!EXT4_I(inode)->i_reserved_data_blocks &&
2839 !EXT4_I(inode)->i_reserved_meta_blocks)
2840 return 0;
2841
2842 /*
2843 * We do something simple for now. The filemap_flush() will
2844 * also start triggering a write of the data blocks, which is
2845 * not strictly speaking necessary (and for users of
2846 * laptop_mode, not even desirable). However, to do otherwise
2847 * would require replicating code paths in:
2848 *
2849 * ext4_writepages() ->
2850 * write_cache_pages() ---> (via passed in callback function)
2851 * __mpage_da_writepage() -->
2852 * mpage_add_bh_to_extent()
2853 * mpage_da_map_blocks()
2854 *
2855 * The problem is that write_cache_pages(), located in
2856 * mm/page-writeback.c, marks pages clean in preparation for
2857 * doing I/O, which is not desirable if we're not planning on
2858 * doing I/O at all.
2859 *
2860 * We could call write_cache_pages(), and then redirty all of
2861 * the pages by calling redirty_page_for_writepage() but that
2862 * would be ugly in the extreme. So instead we would need to
2863 * replicate parts of the code in the above functions,
2864 * simplifying them because we wouldn't actually intend to
2865 * write out the pages, but rather only collect contiguous
2866 * logical block extents, call the multi-block allocator, and
2867 * then update the buffer heads with the block allocations.
2868 *
2869 * For now, though, we'll cheat by calling filemap_flush(),
2870 * which will map the blocks, and start the I/O, but not
2871 * actually wait for the I/O to complete.
2872 */
2873 return filemap_flush(inode->i_mapping);
2874}
2875
2876/*
2877 * bmap() is special. It gets used by applications such as lilo and by
2878 * the swapper to find the on-disk block of a specific piece of data.
2879 *
2880 * Naturally, this is dangerous if the block concerned is still in the
2881 * journal. If somebody makes a swapfile on an ext4 data-journaling
2882 * filesystem and enables swap, then they may get a nasty shock when the
2883 * data getting swapped to that swapfile suddenly gets overwritten by
2884 * the original zero's written out previously to the journal and
2885 * awaiting writeback in the kernel's buffer cache.
2886 *
2887 * So, if we see any bmap calls here on a modified, data-journaled file,
2888 * take extra steps to flush any blocks which might be in the cache.
2889 */
2890static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2891{
2892 struct inode *inode = mapping->host;
2893 journal_t *journal;
2894 int err;
2895
2896 /*
2897 * We can get here for an inline file via the FIBMAP ioctl
2898 */
2899 if (ext4_has_inline_data(inode))
2900 return 0;
2901
2902 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
2903 test_opt(inode->i_sb, DELALLOC)) {
2904 /*
2905 * With delalloc we want to sync the file
2906 * so that we can make sure we allocate
2907 * blocks for file
2908 */
2909 filemap_write_and_wait(mapping);
2910 }
2911
2912 if (EXT4_JOURNAL(inode) &&
2913 ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
2914 /*
2915 * This is a REALLY heavyweight approach, but the use of
2916 * bmap on dirty files is expected to be extremely rare:
2917 * only if we run lilo or swapon on a freshly made file
2918 * do we expect this to happen.
2919 *
2920 * (bmap requires CAP_SYS_RAWIO so this does not
2921 * represent an unprivileged user DOS attack --- we'd be
2922 * in trouble if mortal users could trigger this path at
2923 * will.)
2924 *
2925 * NB. EXT4_STATE_JDATA is not set on files other than
2926 * regular files. If somebody wants to bmap a directory
2927 * or symlink and gets confused because the buffer
2928 * hasn't yet been flushed to disk, they deserve
2929 * everything they get.
2930 */
2931
2932 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
2933 journal = EXT4_JOURNAL(inode);
2934 jbd2_journal_lock_updates(journal);
2935 err = jbd2_journal_flush(journal);
2936 jbd2_journal_unlock_updates(journal);
2937
2938 if (err)
2939 return 0;
2940 }
2941
2942 return generic_block_bmap(mapping, block, ext4_get_block);
2943}
2944
2945static int ext4_readpage(struct file *file, struct page *page)
2946{
2947 int ret = -EAGAIN;
2948 struct inode *inode = page->mapping->host;
2949
2950 trace_ext4_readpage(page);
2951
2952 if (ext4_has_inline_data(inode))
2953 ret = ext4_readpage_inline(inode, page);
2954
2955 if (ret == -EAGAIN)
2956 return mpage_readpage(page, ext4_get_block);
2957
2958 return ret;
2959}
2960
2961static int
2962ext4_readpages(struct file *file, struct address_space *mapping,
2963 struct list_head *pages, unsigned nr_pages)
2964{
2965 struct inode *inode = mapping->host;
2966
2967 /* If the file has inline data, no need to do readpages. */
2968 if (ext4_has_inline_data(inode))
2969 return 0;
2970
2971 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
2972}
2973
2974static void ext4_invalidatepage(struct page *page, unsigned int offset,
2975 unsigned int length)
2976{
2977 trace_ext4_invalidatepage(page, offset, length);
2978
2979 /* No journalling happens on data buffers when this function is used */
2980 WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
2981
2982 block_invalidatepage(page, offset, length);
2983}
2984
2985static int __ext4_journalled_invalidatepage(struct page *page,
2986 unsigned int offset,
2987 unsigned int length)
2988{
2989 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2990
2991 trace_ext4_journalled_invalidatepage(page, offset, length);
2992
2993 /*
2994 * If it's a full truncate we just forget about the pending dirtying
2995 */
2996 if (offset == 0 && length == PAGE_CACHE_SIZE)
2997 ClearPageChecked(page);
2998
2999 return jbd2_journal_invalidatepage(journal, page, offset, length);
3000}
3001
3002/* Wrapper for aops... */
3003static void ext4_journalled_invalidatepage(struct page *page,
3004 unsigned int offset,
3005 unsigned int length)
3006{
3007 WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3008}
3009
3010static int ext4_releasepage(struct page *page, gfp_t wait)
3011{
3012 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3013
3014 trace_ext4_releasepage(page);
3015
3016 /* Page has dirty journalled data -> cannot release */
3017 if (PageChecked(page))
3018 return 0;
3019 if (journal)
3020 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3021 else
3022 return try_to_free_buffers(page);
3023}
3024
3025/*
3026 * ext4_get_block used when preparing for a DIO write or buffer write.
3027 * We allocate an uinitialized extent if blocks haven't been allocated.
3028 * The extent will be converted to initialized after the IO is complete.
3029 */
3030int ext4_get_block_write(struct inode *inode, sector_t iblock,
3031 struct buffer_head *bh_result, int create)
3032{
3033 ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
3034 inode->i_ino, create);
3035 return _ext4_get_block(inode, iblock, bh_result,
3036 EXT4_GET_BLOCKS_IO_CREATE_EXT);
3037}
3038
3039static int ext4_get_block_write_nolock(struct inode *inode, sector_t iblock,
3040 struct buffer_head *bh_result, int create)
3041{
3042 ext4_debug("ext4_get_block_write_nolock: inode %lu, create flag %d\n",
3043 inode->i_ino, create);
3044 return _ext4_get_block(inode, iblock, bh_result,
3045 EXT4_GET_BLOCKS_NO_LOCK);
3046}
3047
3048static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3049 ssize_t size, void *private)
3050{
3051 ext4_io_end_t *io_end = iocb->private;
3052
3053 /* if not async direct IO just return */
3054 if (!io_end)
3055 return;
3056
3057 ext_debug("ext4_end_io_dio(): io_end 0x%p "
3058 "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
3059 iocb->private, io_end->inode->i_ino, iocb, offset,
3060 size);
3061
3062 iocb->private = NULL;
3063 io_end->offset = offset;
3064 io_end->size = size;
3065 ext4_put_io_end(io_end);
3066}
3067
3068/*
3069 * For ext4 extent files, ext4 will do direct-io write to holes,
3070 * preallocated extents, and those write extend the file, no need to
3071 * fall back to buffered IO.
3072 *
3073 * For holes, we fallocate those blocks, mark them as uninitialized
3074 * If those blocks were preallocated, we mark sure they are split, but
3075 * still keep the range to write as uninitialized.
3076 *
3077 * The unwritten extents will be converted to written when DIO is completed.
3078 * For async direct IO, since the IO may still pending when return, we
3079 * set up an end_io call back function, which will do the conversion
3080 * when async direct IO completed.
3081 *
3082 * If the O_DIRECT write will extend the file then add this inode to the
3083 * orphan list. So recovery will truncate it back to the original size
3084 * if the machine crashes during the write.
3085 *
3086 */
3087static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
3088 const struct iovec *iov, loff_t offset,
3089 unsigned long nr_segs)
3090{
3091 struct file *file = iocb->ki_filp;
3092 struct inode *inode = file->f_mapping->host;
3093 ssize_t ret;
3094 size_t count = iov_length(iov, nr_segs);
3095 int overwrite = 0;
3096 get_block_t *get_block_func = NULL;
3097 int dio_flags = 0;
3098 loff_t final_size = offset + count;
3099 ext4_io_end_t *io_end = NULL;
3100
3101 /* Use the old path for reads and writes beyond i_size. */
3102 if (rw != WRITE || final_size > inode->i_size)
3103 return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3104
3105 BUG_ON(iocb->private == NULL);
3106
3107 /*
3108 * Make all waiters for direct IO properly wait also for extent
3109 * conversion. This also disallows race between truncate() and
3110 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
3111 */
3112 if (rw == WRITE)
3113 atomic_inc(&inode->i_dio_count);
3114
3115 /* If we do a overwrite dio, i_mutex locking can be released */
3116 overwrite = *((int *)iocb->private);
3117
3118 if (overwrite) {
3119 down_read(&EXT4_I(inode)->i_data_sem);
3120 mutex_unlock(&inode->i_mutex);
3121 }
3122
3123 /*
3124 * We could direct write to holes and fallocate.
3125 *
3126 * Allocated blocks to fill the hole are marked as
3127 * uninitialized to prevent parallel buffered read to expose
3128 * the stale data before DIO complete the data IO.
3129 *
3130 * As to previously fallocated extents, ext4 get_block will
3131 * just simply mark the buffer mapped but still keep the
3132 * extents uninitialized.
3133 *
3134 * For non AIO case, we will convert those unwritten extents
3135 * to written after return back from blockdev_direct_IO.
3136 *
3137 * For async DIO, the conversion needs to be deferred when the
3138 * IO is completed. The ext4 end_io callback function will be
3139 * called to take care of the conversion work. Here for async
3140 * case, we allocate an io_end structure to hook to the iocb.
3141 */
3142 iocb->private = NULL;
3143 ext4_inode_aio_set(inode, NULL);
3144 if (!is_sync_kiocb(iocb)) {
3145 io_end = ext4_init_io_end(inode, GFP_NOFS);
3146 if (!io_end) {
3147 ret = -ENOMEM;
3148 goto retake_lock;
3149 }
3150 /*
3151 * Grab reference for DIO. Will be dropped in ext4_end_io_dio()
3152 */
3153 iocb->private = ext4_get_io_end(io_end);
3154 /*
3155 * we save the io structure for current async direct
3156 * IO, so that later ext4_map_blocks() could flag the
3157 * io structure whether there is a unwritten extents
3158 * needs to be converted when IO is completed.
3159 */
3160 ext4_inode_aio_set(inode, io_end);
3161 }
3162
3163 if (overwrite) {
3164 get_block_func = ext4_get_block_write_nolock;
3165 } else {
3166 get_block_func = ext4_get_block_write;
3167 dio_flags = DIO_LOCKING;
3168 }
3169 ret = __blockdev_direct_IO(rw, iocb, inode,
3170 inode->i_sb->s_bdev, iov,
3171 offset, nr_segs,
3172 get_block_func,
3173 ext4_end_io_dio,
3174 NULL,
3175 dio_flags);
3176
3177 /*
3178 * Put our reference to io_end. This can free the io_end structure e.g.
3179 * in sync IO case or in case of error. It can even perform extent
3180 * conversion if all bios we submitted finished before we got here.
3181 * Note that in that case iocb->private can be already set to NULL
3182 * here.
3183 */
3184 if (io_end) {
3185 ext4_inode_aio_set(inode, NULL);
3186 ext4_put_io_end(io_end);
3187 /*
3188 * When no IO was submitted ext4_end_io_dio() was not
3189 * called so we have to put iocb's reference.
3190 */
3191 if (ret <= 0 && ret != -EIOCBQUEUED && iocb->private) {
3192 WARN_ON(iocb->private != io_end);
3193 WARN_ON(io_end->flag & EXT4_IO_END_UNWRITTEN);
3194 ext4_put_io_end(io_end);
3195 iocb->private = NULL;
3196 }
3197 }
3198 if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
3199 EXT4_STATE_DIO_UNWRITTEN)) {
3200 int err;
3201 /*
3202 * for non AIO case, since the IO is already
3203 * completed, we could do the conversion right here
3204 */
3205 err = ext4_convert_unwritten_extents(NULL, inode,
3206 offset, ret);
3207 if (err < 0)
3208 ret = err;
3209 ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3210 }
3211
3212retake_lock:
3213 if (rw == WRITE)
3214 inode_dio_done(inode);
3215 /* take i_mutex locking again if we do a ovewrite dio */
3216 if (overwrite) {
3217 up_read(&EXT4_I(inode)->i_data_sem);
3218 mutex_lock(&inode->i_mutex);
3219 }
3220
3221 return ret;
3222}
3223
3224static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3225 const struct iovec *iov, loff_t offset,
3226 unsigned long nr_segs)
3227{
3228 struct file *file = iocb->ki_filp;
3229 struct inode *inode = file->f_mapping->host;
3230 ssize_t ret;
3231
3232 /*
3233 * If we are doing data journalling we don't support O_DIRECT
3234 */
3235 if (ext4_should_journal_data(inode))
3236 return 0;
3237
3238 /* Let buffer I/O handle the inline data case. */
3239 if (ext4_has_inline_data(inode))
3240 return 0;
3241
3242 trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
3243 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3244 ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3245 else
3246 ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3247 trace_ext4_direct_IO_exit(inode, offset,
3248 iov_length(iov, nr_segs), rw, ret);
3249 return ret;
3250}
3251
3252/*
3253 * Pages can be marked dirty completely asynchronously from ext4's journalling
3254 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3255 * much here because ->set_page_dirty is called under VFS locks. The page is
3256 * not necessarily locked.
3257 *
3258 * We cannot just dirty the page and leave attached buffers clean, because the
3259 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3260 * or jbddirty because all the journalling code will explode.
3261 *
3262 * So what we do is to mark the page "pending dirty" and next time writepage
3263 * is called, propagate that into the buffers appropriately.
3264 */
3265static int ext4_journalled_set_page_dirty(struct page *page)
3266{
3267 SetPageChecked(page);
3268 return __set_page_dirty_nobuffers(page);
3269}
3270
3271static const struct address_space_operations ext4_aops = {
3272 .readpage = ext4_readpage,
3273 .readpages = ext4_readpages,
3274 .writepage = ext4_writepage,
3275 .writepages = ext4_writepages,
3276 .write_begin = ext4_write_begin,
3277 .write_end = ext4_write_end,
3278 .bmap = ext4_bmap,
3279 .invalidatepage = ext4_invalidatepage,
3280 .releasepage = ext4_releasepage,
3281 .direct_IO = ext4_direct_IO,
3282 .migratepage = buffer_migrate_page,
3283 .is_partially_uptodate = block_is_partially_uptodate,
3284 .error_remove_page = generic_error_remove_page,
3285};
3286
3287static const struct address_space_operations ext4_journalled_aops = {
3288 .readpage = ext4_readpage,
3289 .readpages = ext4_readpages,
3290 .writepage = ext4_writepage,
3291 .writepages = ext4_writepages,
3292 .write_begin = ext4_write_begin,
3293 .write_end = ext4_journalled_write_end,
3294 .set_page_dirty = ext4_journalled_set_page_dirty,
3295 .bmap = ext4_bmap,
3296 .invalidatepage = ext4_journalled_invalidatepage,
3297 .releasepage = ext4_releasepage,
3298 .direct_IO = ext4_direct_IO,
3299 .is_partially_uptodate = block_is_partially_uptodate,
3300 .error_remove_page = generic_error_remove_page,
3301};
3302
3303static const struct address_space_operations ext4_da_aops = {
3304 .readpage = ext4_readpage,
3305 .readpages = ext4_readpages,
3306 .writepage = ext4_writepage,
3307 .writepages = ext4_writepages,
3308 .write_begin = ext4_da_write_begin,
3309 .write_end = ext4_da_write_end,
3310 .bmap = ext4_bmap,
3311 .invalidatepage = ext4_da_invalidatepage,
3312 .releasepage = ext4_releasepage,
3313 .direct_IO = ext4_direct_IO,
3314 .migratepage = buffer_migrate_page,
3315 .is_partially_uptodate = block_is_partially_uptodate,
3316 .error_remove_page = generic_error_remove_page,
3317};
3318
3319void ext4_set_aops(struct inode *inode)
3320{
3321 switch (ext4_inode_journal_mode(inode)) {
3322 case EXT4_INODE_ORDERED_DATA_MODE:
3323 ext4_set_inode_state(inode, EXT4_STATE_ORDERED_MODE);
3324 break;
3325 case EXT4_INODE_WRITEBACK_DATA_MODE:
3326 ext4_clear_inode_state(inode, EXT4_STATE_ORDERED_MODE);
3327 break;
3328 case EXT4_INODE_JOURNAL_DATA_MODE:
3329 inode->i_mapping->a_ops = &ext4_journalled_aops;
3330 return;
3331 default:
3332 BUG();
3333 }
3334 if (test_opt(inode->i_sb, DELALLOC))
3335 inode->i_mapping->a_ops = &ext4_da_aops;
3336 else
3337 inode->i_mapping->a_ops = &ext4_aops;
3338}
3339
3340/*
3341 * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3342 * starting from file offset 'from'. The range to be zero'd must
3343 * be contained with in one block. If the specified range exceeds
3344 * the end of the block it will be shortened to end of the block
3345 * that cooresponds to 'from'
3346 */
3347static int ext4_block_zero_page_range(handle_t *handle,
3348 struct address_space *mapping, loff_t from, loff_t length)
3349{
3350 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3351 unsigned offset = from & (PAGE_CACHE_SIZE-1);
3352 unsigned blocksize, max, pos;
3353 ext4_lblk_t iblock;
3354 struct inode *inode = mapping->host;
3355 struct buffer_head *bh;
3356 struct page *page;
3357 int err = 0;
3358
3359 page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3360 mapping_gfp_mask(mapping) & ~__GFP_FS);
3361 if (!page)
3362 return -ENOMEM;
3363
3364 blocksize = inode->i_sb->s_blocksize;
3365 max = blocksize - (offset & (blocksize - 1));
3366
3367 /*
3368 * correct length if it does not fall between
3369 * 'from' and the end of the block
3370 */
3371 if (length > max || length < 0)
3372 length = max;
3373
3374 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3375
3376 if (!page_has_buffers(page))
3377 create_empty_buffers(page, blocksize, 0);
3378
3379 /* Find the buffer that contains "offset" */
3380 bh = page_buffers(page);
3381 pos = blocksize;
3382 while (offset >= pos) {
3383 bh = bh->b_this_page;
3384 iblock++;
3385 pos += blocksize;
3386 }
3387 if (buffer_freed(bh)) {
3388 BUFFER_TRACE(bh, "freed: skip");
3389 goto unlock;
3390 }
3391 if (!buffer_mapped(bh)) {
3392 BUFFER_TRACE(bh, "unmapped");
3393 ext4_get_block(inode, iblock, bh, 0);
3394 /* unmapped? It's a hole - nothing to do */
3395 if (!buffer_mapped(bh)) {
3396 BUFFER_TRACE(bh, "still unmapped");
3397 goto unlock;
3398 }
3399 }
3400
3401 /* Ok, it's mapped. Make sure it's up-to-date */
3402 if (PageUptodate(page))
3403 set_buffer_uptodate(bh);
3404
3405 if (!buffer_uptodate(bh)) {
3406 err = -EIO;
3407 ll_rw_block(READ, 1, &bh);
3408 wait_on_buffer(bh);
3409 /* Uhhuh. Read error. Complain and punt. */
3410 if (!buffer_uptodate(bh))
3411 goto unlock;
3412 }
3413 if (ext4_should_journal_data(inode)) {
3414 BUFFER_TRACE(bh, "get write access");
3415 err = ext4_journal_get_write_access(handle, bh);
3416 if (err)
3417 goto unlock;
3418 }
3419 zero_user(page, offset, length);
3420 BUFFER_TRACE(bh, "zeroed end of block");
3421
3422 if (ext4_should_journal_data(inode)) {
3423 err = ext4_handle_dirty_metadata(handle, inode, bh);
3424 } else {
3425 err = 0;
3426 mark_buffer_dirty(bh);
3427 if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE))
3428 err = ext4_jbd2_file_inode(handle, inode);
3429 }
3430
3431unlock:
3432 unlock_page(page);
3433 page_cache_release(page);
3434 return err;
3435}
3436
3437/*
3438 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3439 * up to the end of the block which corresponds to `from'.
3440 * This required during truncate. We need to physically zero the tail end
3441 * of that block so it doesn't yield old data if the file is later grown.
3442 */
3443int ext4_block_truncate_page(handle_t *handle,
3444 struct address_space *mapping, loff_t from)
3445{
3446 unsigned offset = from & (PAGE_CACHE_SIZE-1);
3447 unsigned length;
3448 unsigned blocksize;
3449 struct inode *inode = mapping->host;
3450
3451 blocksize = inode->i_sb->s_blocksize;
3452 length = blocksize - (offset & (blocksize - 1));
3453
3454 return ext4_block_zero_page_range(handle, mapping, from, length);
3455}
3456
3457int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3458 loff_t lstart, loff_t length)
3459{
3460 struct super_block *sb = inode->i_sb;
3461 struct address_space *mapping = inode->i_mapping;
3462 unsigned partial_start, partial_end;
3463 ext4_fsblk_t start, end;
3464 loff_t byte_end = (lstart + length - 1);
3465 int err = 0;
3466
3467 partial_start = lstart & (sb->s_blocksize - 1);
3468 partial_end = byte_end & (sb->s_blocksize - 1);
3469
3470 start = lstart >> sb->s_blocksize_bits;
3471 end = byte_end >> sb->s_blocksize_bits;
3472
3473 /* Handle partial zero within the single block */
3474 if (start == end &&
3475 (partial_start || (partial_end != sb->s_blocksize - 1))) {
3476 err = ext4_block_zero_page_range(handle, mapping,
3477 lstart, length);
3478 return err;
3479 }
3480 /* Handle partial zero out on the start of the range */
3481 if (partial_start) {
3482 err = ext4_block_zero_page_range(handle, mapping,
3483 lstart, sb->s_blocksize);
3484 if (err)
3485 return err;
3486 }
3487 /* Handle partial zero out on the end of the range */
3488 if (partial_end != sb->s_blocksize - 1)
3489 err = ext4_block_zero_page_range(handle, mapping,
3490 byte_end - partial_end,
3491 partial_end + 1);
3492 return err;
3493}
3494
3495int ext4_can_truncate(struct inode *inode)
3496{
3497 if (S_ISREG(inode->i_mode))
3498 return 1;
3499 if (S_ISDIR(inode->i_mode))
3500 return 1;
3501 if (S_ISLNK(inode->i_mode))
3502 return !ext4_inode_is_fast_symlink(inode);
3503 return 0;
3504}
3505
3506/*
3507 * ext4_punch_hole: punches a hole in a file by releaseing the blocks
3508 * associated with the given offset and length
3509 *
3510 * @inode: File inode
3511 * @offset: The offset where the hole will begin
3512 * @len: The length of the hole
3513 *
3514 * Returns: 0 on success or negative on failure
3515 */
3516
3517int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
3518{
3519 struct super_block *sb = inode->i_sb;
3520 ext4_lblk_t first_block, stop_block;
3521 struct address_space *mapping = inode->i_mapping;
3522 loff_t first_block_offset, last_block_offset;
3523 handle_t *handle;
3524 unsigned int credits;
3525 int ret = 0;
3526
3527 if (!S_ISREG(inode->i_mode))
3528 return -EOPNOTSUPP;
3529
3530 trace_ext4_punch_hole(inode, offset, length, 0);
3531
3532 /*
3533 * Write out all dirty pages to avoid race conditions
3534 * Then release them.
3535 */
3536 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3537 ret = filemap_write_and_wait_range(mapping, offset,
3538 offset + length - 1);
3539 if (ret)
3540 return ret;
3541 }
3542
3543 mutex_lock(&inode->i_mutex);
3544
3545 /* No need to punch hole beyond i_size */
3546 if (offset >= inode->i_size)
3547 goto out_mutex;
3548
3549 /*
3550 * If the hole extends beyond i_size, set the hole
3551 * to end after the page that contains i_size
3552 */
3553 if (offset + length > inode->i_size) {
3554 length = inode->i_size +
3555 PAGE_CACHE_SIZE - (inode->i_size & (PAGE_CACHE_SIZE - 1)) -
3556 offset;
3557 }
3558
3559 if (offset & (sb->s_blocksize - 1) ||
3560 (offset + length) & (sb->s_blocksize - 1)) {
3561 /*
3562 * Attach jinode to inode for jbd2 if we do any zeroing of
3563 * partial block
3564 */
3565 ret = ext4_inode_attach_jinode(inode);
3566 if (ret < 0)
3567 goto out_mutex;
3568
3569 }
3570
3571 first_block_offset = round_up(offset, sb->s_blocksize);
3572 last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
3573
3574 /* Now release the pages and zero block aligned part of pages*/
3575 if (last_block_offset > first_block_offset)
3576 truncate_pagecache_range(inode, first_block_offset,
3577 last_block_offset);
3578
3579 /* Wait all existing dio workers, newcomers will block on i_mutex */
3580 ext4_inode_block_unlocked_dio(inode);
3581 inode_dio_wait(inode);
3582
3583 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3584 credits = ext4_writepage_trans_blocks(inode);
3585 else
3586 credits = ext4_blocks_for_truncate(inode);
3587 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
3588 if (IS_ERR(handle)) {
3589 ret = PTR_ERR(handle);
3590 ext4_std_error(sb, ret);
3591 goto out_dio;
3592 }
3593
3594 ret = ext4_zero_partial_blocks(handle, inode, offset,
3595 length);
3596 if (ret)
3597 goto out_stop;
3598
3599 first_block = (offset + sb->s_blocksize - 1) >>
3600 EXT4_BLOCK_SIZE_BITS(sb);
3601 stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
3602
3603 /* If there are no blocks to remove, return now */
3604 if (first_block >= stop_block)
3605 goto out_stop;
3606
3607 down_write(&EXT4_I(inode)->i_data_sem);
3608 ext4_discard_preallocations(inode);
3609
3610 ret = ext4_es_remove_extent(inode, first_block,
3611 stop_block - first_block);
3612 if (ret) {
3613 up_write(&EXT4_I(inode)->i_data_sem);
3614 goto out_stop;
3615 }
3616
3617 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3618 ret = ext4_ext_remove_space(inode, first_block,
3619 stop_block - 1);
3620 else
3621 ret = ext4_free_hole_blocks(handle, inode, first_block,
3622 stop_block);
3623
3624 up_write(&EXT4_I(inode)->i_data_sem);
3625 if (IS_SYNC(inode))
3626 ext4_handle_sync(handle);
3627
3628 /* Now release the pages again to reduce race window */
3629 if (last_block_offset > first_block_offset)
3630 truncate_pagecache_range(inode, first_block_offset,
3631 last_block_offset);
3632
3633 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3634 ext4_mark_inode_dirty(handle, inode);
3635out_stop:
3636 ext4_journal_stop(handle);
3637out_dio:
3638 ext4_inode_resume_unlocked_dio(inode);
3639out_mutex:
3640 mutex_unlock(&inode->i_mutex);
3641 return ret;
3642}
3643
3644int ext4_inode_attach_jinode(struct inode *inode)
3645{
3646 struct ext4_inode_info *ei = EXT4_I(inode);
3647 struct jbd2_inode *jinode;
3648
3649 if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
3650 return 0;
3651
3652 jinode = jbd2_alloc_inode(GFP_KERNEL);
3653 spin_lock(&inode->i_lock);
3654 if (!ei->jinode) {
3655 if (!jinode) {
3656 spin_unlock(&inode->i_lock);
3657 return -ENOMEM;
3658 }
3659 ei->jinode = jinode;
3660 jbd2_journal_init_jbd_inode(ei->jinode, inode);
3661 jinode = NULL;
3662 }
3663 spin_unlock(&inode->i_lock);
3664 if (unlikely(jinode != NULL))
3665 jbd2_free_inode(jinode);
3666 return 0;
3667}
3668
3669/*
3670 * ext4_truncate()
3671 *
3672 * We block out ext4_get_block() block instantiations across the entire
3673 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3674 * simultaneously on behalf of the same inode.
3675 *
3676 * As we work through the truncate and commit bits of it to the journal there
3677 * is one core, guiding principle: the file's tree must always be consistent on
3678 * disk. We must be able to restart the truncate after a crash.
3679 *
3680 * The file's tree may be transiently inconsistent in memory (although it
3681 * probably isn't), but whenever we close off and commit a journal transaction,
3682 * the contents of (the filesystem + the journal) must be consistent and
3683 * restartable. It's pretty simple, really: bottom up, right to left (although
3684 * left-to-right works OK too).
3685 *
3686 * Note that at recovery time, journal replay occurs *before* the restart of
3687 * truncate against the orphan inode list.
3688 *
3689 * The committed inode has the new, desired i_size (which is the same as
3690 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
3691 * that this inode's truncate did not complete and it will again call
3692 * ext4_truncate() to have another go. So there will be instantiated blocks
3693 * to the right of the truncation point in a crashed ext4 filesystem. But
3694 * that's fine - as long as they are linked from the inode, the post-crash
3695 * ext4_truncate() run will find them and release them.
3696 */
3697void ext4_truncate(struct inode *inode)
3698{
3699 struct ext4_inode_info *ei = EXT4_I(inode);
3700 unsigned int credits;
3701 handle_t *handle;
3702 struct address_space *mapping = inode->i_mapping;
3703
3704 /*
3705 * There is a possibility that we're either freeing the inode
3706 * or it's a completely new inode. In those cases we might not
3707 * have i_mutex locked because it's not necessary.
3708 */
3709 if (!(inode->i_state & (I_NEW|I_FREEING)))
3710 WARN_ON(!mutex_is_locked(&inode->i_mutex));
3711 trace_ext4_truncate_enter(inode);
3712
3713 if (!ext4_can_truncate(inode))
3714 return;
3715
3716 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3717
3718 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
3719 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
3720
3721 if (ext4_has_inline_data(inode)) {
3722 int has_inline = 1;
3723
3724 ext4_inline_data_truncate(inode, &has_inline);
3725 if (has_inline)
3726 return;
3727 }
3728
3729 /* If we zero-out tail of the page, we have to create jinode for jbd2 */
3730 if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
3731 if (ext4_inode_attach_jinode(inode) < 0)
3732 return;
3733 }
3734
3735 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3736 credits = ext4_writepage_trans_blocks(inode);
3737 else
3738 credits = ext4_blocks_for_truncate(inode);
3739
3740 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
3741 if (IS_ERR(handle)) {
3742 ext4_std_error(inode->i_sb, PTR_ERR(handle));
3743 return;
3744 }
3745
3746 if (inode->i_size & (inode->i_sb->s_blocksize - 1))
3747 ext4_block_truncate_page(handle, mapping, inode->i_size);
3748
3749 /*
3750 * We add the inode to the orphan list, so that if this
3751 * truncate spans multiple transactions, and we crash, we will
3752 * resume the truncate when the filesystem recovers. It also
3753 * marks the inode dirty, to catch the new size.
3754 *
3755 * Implication: the file must always be in a sane, consistent
3756 * truncatable state while each transaction commits.
3757 */
3758 if (ext4_orphan_add(handle, inode))
3759 goto out_stop;
3760
3761 down_write(&EXT4_I(inode)->i_data_sem);
3762
3763 ext4_discard_preallocations(inode);
3764
3765 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3766 ext4_ext_truncate(handle, inode);
3767 else
3768 ext4_ind_truncate(handle, inode);
3769
3770 up_write(&ei->i_data_sem);
3771
3772 if (IS_SYNC(inode))
3773 ext4_handle_sync(handle);
3774
3775out_stop:
3776 /*
3777 * If this was a simple ftruncate() and the file will remain alive,
3778 * then we need to clear up the orphan record which we created above.
3779 * However, if this was a real unlink then we were called by
3780 * ext4_delete_inode(), and we allow that function to clean up the
3781 * orphan info for us.
3782 */
3783 if (inode->i_nlink)
3784 ext4_orphan_del(handle, inode);
3785
3786 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3787 ext4_mark_inode_dirty(handle, inode);
3788 ext4_journal_stop(handle);
3789
3790 trace_ext4_truncate_exit(inode);
3791}
3792
3793/*
3794 * ext4_get_inode_loc returns with an extra refcount against the inode's
3795 * underlying buffer_head on success. If 'in_mem' is true, we have all
3796 * data in memory that is needed to recreate the on-disk version of this
3797 * inode.
3798 */
3799static int __ext4_get_inode_loc(struct inode *inode,
3800 struct ext4_iloc *iloc, int in_mem)
3801{
3802 struct ext4_group_desc *gdp;
3803 struct buffer_head *bh;
3804 struct super_block *sb = inode->i_sb;
3805 ext4_fsblk_t block;
3806 int inodes_per_block, inode_offset;
3807
3808 iloc->bh = NULL;
3809 if (!ext4_valid_inum(sb, inode->i_ino))
3810 return -EIO;
3811
3812 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
3813 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
3814 if (!gdp)
3815 return -EIO;
3816
3817 /*
3818 * Figure out the offset within the block group inode table
3819 */
3820 inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
3821 inode_offset = ((inode->i_ino - 1) %
3822 EXT4_INODES_PER_GROUP(sb));
3823 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
3824 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
3825
3826 bh = sb_getblk(sb, block);
3827 if (unlikely(!bh))
3828 return -ENOMEM;
3829 if (!buffer_uptodate(bh)) {
3830 lock_buffer(bh);
3831
3832 /*
3833 * If the buffer has the write error flag, we have failed
3834 * to write out another inode in the same block. In this
3835 * case, we don't have to read the block because we may
3836 * read the old inode data successfully.
3837 */
3838 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
3839 set_buffer_uptodate(bh);
3840
3841 if (buffer_uptodate(bh)) {
3842 /* someone brought it uptodate while we waited */
3843 unlock_buffer(bh);
3844 goto has_buffer;
3845 }
3846
3847 /*
3848 * If we have all information of the inode in memory and this
3849 * is the only valid inode in the block, we need not read the
3850 * block.
3851 */
3852 if (in_mem) {
3853 struct buffer_head *bitmap_bh;
3854 int i, start;
3855
3856 start = inode_offset & ~(inodes_per_block - 1);
3857
3858 /* Is the inode bitmap in cache? */
3859 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
3860 if (unlikely(!bitmap_bh))
3861 goto make_io;
3862
3863 /*
3864 * If the inode bitmap isn't in cache then the
3865 * optimisation may end up performing two reads instead
3866 * of one, so skip it.
3867 */
3868 if (!buffer_uptodate(bitmap_bh)) {
3869 brelse(bitmap_bh);
3870 goto make_io;
3871 }
3872 for (i = start; i < start + inodes_per_block; i++) {
3873 if (i == inode_offset)
3874 continue;
3875 if (ext4_test_bit(i, bitmap_bh->b_data))
3876 break;
3877 }
3878 brelse(bitmap_bh);
3879 if (i == start + inodes_per_block) {
3880 /* all other inodes are free, so skip I/O */
3881 memset(bh->b_data, 0, bh->b_size);
3882 set_buffer_uptodate(bh);
3883 unlock_buffer(bh);
3884 goto has_buffer;
3885 }
3886 }
3887
3888make_io:
3889 /*
3890 * If we need to do any I/O, try to pre-readahead extra
3891 * blocks from the inode table.
3892 */
3893 if (EXT4_SB(sb)->s_inode_readahead_blks) {
3894 ext4_fsblk_t b, end, table;
3895 unsigned num;
3896 __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
3897
3898 table = ext4_inode_table(sb, gdp);
3899 /* s_inode_readahead_blks is always a power of 2 */
3900 b = block & ~((ext4_fsblk_t) ra_blks - 1);
3901 if (table > b)
3902 b = table;
3903 end = b + ra_blks;
3904 num = EXT4_INODES_PER_GROUP(sb);
3905 if (ext4_has_group_desc_csum(sb))
3906 num -= ext4_itable_unused_count(sb, gdp);
3907 table += num / inodes_per_block;
3908 if (end > table)
3909 end = table;
3910 while (b <= end)
3911 sb_breadahead(sb, b++);
3912 }
3913
3914 /*
3915 * There are other valid inodes in the buffer, this inode
3916 * has in-inode xattrs, or we don't have this inode in memory.
3917 * Read the block from disk.
3918 */
3919 trace_ext4_load_inode(inode);
3920 get_bh(bh);
3921 bh->b_end_io = end_buffer_read_sync;
3922 submit_bh(READ | REQ_META | REQ_PRIO, bh);
3923 wait_on_buffer(bh);
3924 if (!buffer_uptodate(bh)) {
3925 EXT4_ERROR_INODE_BLOCK(inode, block,
3926 "unable to read itable block");
3927 brelse(bh);
3928 return -EIO;
3929 }
3930 }
3931has_buffer:
3932 iloc->bh = bh;
3933 return 0;
3934}
3935
3936int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
3937{
3938 /* We have all inode data except xattrs in memory here. */
3939 return __ext4_get_inode_loc(inode, iloc,
3940 !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
3941}
3942
3943void ext4_set_inode_flags(struct inode *inode)
3944{
3945 unsigned int flags = EXT4_I(inode)->i_flags;
3946 unsigned int new_fl = 0;
3947
3948 if (flags & EXT4_SYNC_FL)
3949 new_fl |= S_SYNC;
3950 if (flags & EXT4_APPEND_FL)
3951 new_fl |= S_APPEND;
3952 if (flags & EXT4_IMMUTABLE_FL)
3953 new_fl |= S_IMMUTABLE;
3954 if (flags & EXT4_NOATIME_FL)
3955 new_fl |= S_NOATIME;
3956 if (flags & EXT4_DIRSYNC_FL)
3957 new_fl |= S_DIRSYNC;
3958 inode_set_flags(inode, new_fl,
3959 S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
3960}
3961
3962/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
3963void ext4_get_inode_flags(struct ext4_inode_info *ei)
3964{
3965 unsigned int vfs_fl;
3966 unsigned long old_fl, new_fl;
3967
3968 do {
3969 vfs_fl = ei->vfs_inode.i_flags;
3970 old_fl = ei->i_flags;
3971 new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
3972 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
3973 EXT4_DIRSYNC_FL);
3974 if (vfs_fl & S_SYNC)
3975 new_fl |= EXT4_SYNC_FL;
3976 if (vfs_fl & S_APPEND)
3977 new_fl |= EXT4_APPEND_FL;
3978 if (vfs_fl & S_IMMUTABLE)
3979 new_fl |= EXT4_IMMUTABLE_FL;
3980 if (vfs_fl & S_NOATIME)
3981 new_fl |= EXT4_NOATIME_FL;
3982 if (vfs_fl & S_DIRSYNC)
3983 new_fl |= EXT4_DIRSYNC_FL;
3984 } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
3985}
3986
3987static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
3988 struct ext4_inode_info *ei)
3989{
3990 blkcnt_t i_blocks ;
3991 struct inode *inode = &(ei->vfs_inode);
3992 struct super_block *sb = inode->i_sb;
3993
3994 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3995 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
3996 /* we are using combined 48 bit field */
3997 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
3998 le32_to_cpu(raw_inode->i_blocks_lo);
3999 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4000 /* i_blocks represent file system block size */
4001 return i_blocks << (inode->i_blkbits - 9);
4002 } else {
4003 return i_blocks;
4004 }
4005 } else {
4006 return le32_to_cpu(raw_inode->i_blocks_lo);
4007 }
4008}
4009
4010static inline void ext4_iget_extra_inode(struct inode *inode,
4011 struct ext4_inode *raw_inode,
4012 struct ext4_inode_info *ei)
4013{
4014 __le32 *magic = (void *)raw_inode +
4015 EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4016 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4017 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4018 ext4_find_inline_data_nolock(inode);
4019 } else
4020 EXT4_I(inode)->i_inline_off = 0;
4021}
4022
4023struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4024{
4025 struct ext4_iloc iloc;
4026 struct ext4_inode *raw_inode;
4027 struct ext4_inode_info *ei;
4028 struct inode *inode;
4029 journal_t *journal = EXT4_SB(sb)->s_journal;
4030 long ret;
4031 int block;
4032 uid_t i_uid;
4033 gid_t i_gid;
4034
4035 inode = iget_locked(sb, ino);
4036 if (!inode)
4037 return ERR_PTR(-ENOMEM);
4038 if (!(inode->i_state & I_NEW))
4039 return inode;
4040
4041 ei = EXT4_I(inode);
4042 iloc.bh = NULL;
4043
4044 ret = __ext4_get_inode_loc(inode, &iloc, 0);
4045 if (ret < 0)
4046 goto bad_inode;
4047 raw_inode = ext4_raw_inode(&iloc);
4048
4049 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4050 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4051 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4052 EXT4_INODE_SIZE(inode->i_sb)) {
4053 EXT4_ERROR_INODE(inode, "bad extra_isize (%u != %u)",
4054 EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize,
4055 EXT4_INODE_SIZE(inode->i_sb));
4056 ret = -EIO;
4057 goto bad_inode;
4058 }
4059 } else
4060 ei->i_extra_isize = 0;
4061
4062 /* Precompute checksum seed for inode metadata */
4063 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4064 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
4065 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4066 __u32 csum;
4067 __le32 inum = cpu_to_le32(inode->i_ino);
4068 __le32 gen = raw_inode->i_generation;
4069 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4070 sizeof(inum));
4071 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4072 sizeof(gen));
4073 }
4074
4075 if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
4076 EXT4_ERROR_INODE(inode, "checksum invalid");
4077 ret = -EIO;
4078 goto bad_inode;
4079 }
4080
4081 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4082 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4083 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4084 if (!(test_opt(inode->i_sb, NO_UID32))) {
4085 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4086 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4087 }
4088 i_uid_write(inode, i_uid);
4089 i_gid_write(inode, i_gid);
4090 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4091
4092 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
4093 ei->i_inline_off = 0;
4094 ei->i_dir_start_lookup = 0;
4095 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4096 /* We now have enough fields to check if the inode was active or not.
4097 * This is needed because nfsd might try to access dead inodes
4098 * the test is that same one that e2fsck uses
4099 * NeilBrown 1999oct15
4100 */
4101 if (inode->i_nlink == 0) {
4102 if ((inode->i_mode == 0 ||
4103 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4104 ino != EXT4_BOOT_LOADER_INO) {
4105 /* this inode is deleted */
4106 ret = -ESTALE;
4107 goto bad_inode;
4108 }
4109 /* The only unlinked inodes we let through here have
4110 * valid i_mode and are being read by the orphan
4111 * recovery code: that's fine, we're about to complete
4112 * the process of deleting those.
4113 * OR it is the EXT4_BOOT_LOADER_INO which is
4114 * not initialized on a new filesystem. */
4115 }
4116 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4117 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4118 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4119 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
4120 ei->i_file_acl |=
4121 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4122 inode->i_size = ext4_isize(raw_inode);
4123 ei->i_disksize = inode->i_size;
4124#ifdef CONFIG_QUOTA
4125 ei->i_reserved_quota = 0;
4126#endif
4127 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4128 ei->i_block_group = iloc.block_group;
4129 ei->i_last_alloc_group = ~0;
4130 /*
4131 * NOTE! The in-memory inode i_data array is in little-endian order
4132 * even on big-endian machines: we do NOT byteswap the block numbers!
4133 */
4134 for (block = 0; block < EXT4_N_BLOCKS; block++)
4135 ei->i_data[block] = raw_inode->i_block[block];
4136 INIT_LIST_HEAD(&ei->i_orphan);
4137
4138 /*
4139 * Set transaction id's of transactions that have to be committed
4140 * to finish f[data]sync. We set them to currently running transaction
4141 * as we cannot be sure that the inode or some of its metadata isn't
4142 * part of the transaction - the inode could have been reclaimed and
4143 * now it is reread from disk.
4144 */
4145 if (journal) {
4146 transaction_t *transaction;
4147 tid_t tid;
4148
4149 read_lock(&journal->j_state_lock);
4150 if (journal->j_running_transaction)
4151 transaction = journal->j_running_transaction;
4152 else
4153 transaction = journal->j_committing_transaction;
4154 if (transaction)
4155 tid = transaction->t_tid;
4156 else
4157 tid = journal->j_commit_sequence;
4158 read_unlock(&journal->j_state_lock);
4159 ei->i_sync_tid = tid;
4160 ei->i_datasync_tid = tid;
4161 }
4162
4163 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4164 if (ei->i_extra_isize == 0) {
4165 /* The extra space is currently unused. Use it. */
4166 ei->i_extra_isize = sizeof(struct ext4_inode) -
4167 EXT4_GOOD_OLD_INODE_SIZE;
4168 } else {
4169 ext4_iget_extra_inode(inode, raw_inode, ei);
4170 }
4171 }
4172
4173 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4174 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4175 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4176 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4177
4178 if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4179 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4180 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4181 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4182 inode->i_version |=
4183 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4184 }
4185 }
4186
4187 ret = 0;
4188 if (ei->i_file_acl &&
4189 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
4190 EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
4191 ei->i_file_acl);
4192 ret = -EIO;
4193 goto bad_inode;
4194 } else if (!ext4_has_inline_data(inode)) {
4195 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
4196 if ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4197 (S_ISLNK(inode->i_mode) &&
4198 !ext4_inode_is_fast_symlink(inode))))
4199 /* Validate extent which is part of inode */
4200 ret = ext4_ext_check_inode(inode);
4201 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4202 (S_ISLNK(inode->i_mode) &&
4203 !ext4_inode_is_fast_symlink(inode))) {
4204 /* Validate block references which are part of inode */
4205 ret = ext4_ind_check_inode(inode);
4206 }
4207 }
4208 if (ret)
4209 goto bad_inode;
4210
4211 if (S_ISREG(inode->i_mode)) {
4212 inode->i_op = &ext4_file_inode_operations;
4213 inode->i_fop = &ext4_file_operations;
4214 ext4_set_aops(inode);
4215 } else if (S_ISDIR(inode->i_mode)) {
4216 inode->i_op = &ext4_dir_inode_operations;
4217 inode->i_fop = &ext4_dir_operations;
4218 } else if (S_ISLNK(inode->i_mode)) {
4219 if (ext4_inode_is_fast_symlink(inode)) {
4220 inode->i_op = &ext4_fast_symlink_inode_operations;
4221 nd_terminate_link(ei->i_data, inode->i_size,
4222 sizeof(ei->i_data) - 1);
4223 } else {
4224 inode->i_op = &ext4_symlink_inode_operations;
4225 ext4_set_aops(inode);
4226 }
4227 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4228 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4229 inode->i_op = &ext4_special_inode_operations;
4230 if (raw_inode->i_block[0])
4231 init_special_inode(inode, inode->i_mode,
4232 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4233 else
4234 init_special_inode(inode, inode->i_mode,
4235 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4236 } else if (ino == EXT4_BOOT_LOADER_INO) {
4237 make_bad_inode(inode);
4238 } else {
4239 ret = -EIO;
4240 EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
4241 goto bad_inode;
4242 }
4243 brelse(iloc.bh);
4244 ext4_set_inode_flags(inode);
4245 unlock_new_inode(inode);
4246 return inode;
4247
4248bad_inode:
4249 brelse(iloc.bh);
4250 iget_failed(inode);
4251 return ERR_PTR(ret);
4252}
4253
4254static int ext4_inode_blocks_set(handle_t *handle,
4255 struct ext4_inode *raw_inode,
4256 struct ext4_inode_info *ei)
4257{
4258 struct inode *inode = &(ei->vfs_inode);
4259 u64 i_blocks = inode->i_blocks;
4260 struct super_block *sb = inode->i_sb;
4261
4262 if (i_blocks <= ~0U) {
4263 /*
4264 * i_blocks can be represented in a 32 bit variable
4265 * as multiple of 512 bytes
4266 */
4267 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4268 raw_inode->i_blocks_high = 0;
4269 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4270 return 0;
4271 }
4272 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
4273 return -EFBIG;
4274
4275 if (i_blocks <= 0xffffffffffffULL) {
4276 /*
4277 * i_blocks can be represented in a 48 bit variable
4278 * as multiple of 512 bytes
4279 */
4280 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4281 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4282 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4283 } else {
4284 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4285 /* i_block is stored in file system block size */
4286 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4287 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4288 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4289 }
4290 return 0;
4291}
4292
4293/*
4294 * Post the struct inode info into an on-disk inode location in the
4295 * buffer-cache. This gobbles the caller's reference to the
4296 * buffer_head in the inode location struct.
4297 *
4298 * The caller must have write access to iloc->bh.
4299 */
4300static int ext4_do_update_inode(handle_t *handle,
4301 struct inode *inode,
4302 struct ext4_iloc *iloc)
4303{
4304 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4305 struct ext4_inode_info *ei = EXT4_I(inode);
4306 struct buffer_head *bh = iloc->bh;
4307 int err = 0, rc, block;
4308 int need_datasync = 0;
4309 uid_t i_uid;
4310 gid_t i_gid;
4311
4312 /* For fields not not tracking in the in-memory inode,
4313 * initialise them to zero for new inodes. */
4314 if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
4315 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4316
4317 ext4_get_inode_flags(ei);
4318 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4319 i_uid = i_uid_read(inode);
4320 i_gid = i_gid_read(inode);
4321 if (!(test_opt(inode->i_sb, NO_UID32))) {
4322 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4323 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4324/*
4325 * Fix up interoperability with old kernels. Otherwise, old inodes get
4326 * re-used with the upper 16 bits of the uid/gid intact
4327 */
4328 if (!ei->i_dtime) {
4329 raw_inode->i_uid_high =
4330 cpu_to_le16(high_16_bits(i_uid));
4331 raw_inode->i_gid_high =
4332 cpu_to_le16(high_16_bits(i_gid));
4333 } else {
4334 raw_inode->i_uid_high = 0;
4335 raw_inode->i_gid_high = 0;
4336 }
4337 } else {
4338 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4339 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4340 raw_inode->i_uid_high = 0;
4341 raw_inode->i_gid_high = 0;
4342 }
4343 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4344
4345 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4346 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4347 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4348 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4349
4350 if (ext4_inode_blocks_set(handle, raw_inode, ei))
4351 goto out_brelse;
4352 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4353 raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4354 if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4355 raw_inode->i_file_acl_high =
4356 cpu_to_le16(ei->i_file_acl >> 32);
4357 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4358 if (ei->i_disksize != ext4_isize(raw_inode)) {
4359 ext4_isize_set(raw_inode, ei->i_disksize);
4360 need_datasync = 1;
4361 }
4362 if (ei->i_disksize > 0x7fffffffULL) {
4363 struct super_block *sb = inode->i_sb;
4364 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
4365 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
4366 EXT4_SB(sb)->s_es->s_rev_level ==
4367 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
4368 /* If this is the first large file
4369 * created, add a flag to the superblock.
4370 */
4371 err = ext4_journal_get_write_access(handle,
4372 EXT4_SB(sb)->s_sbh);
4373 if (err)
4374 goto out_brelse;
4375 ext4_update_dynamic_rev(sb);
4376 EXT4_SET_RO_COMPAT_FEATURE(sb,
4377 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4378 ext4_handle_sync(handle);
4379 err = ext4_handle_dirty_super(handle, sb);
4380 }
4381 }
4382 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4383 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4384 if (old_valid_dev(inode->i_rdev)) {
4385 raw_inode->i_block[0] =
4386 cpu_to_le32(old_encode_dev(inode->i_rdev));
4387 raw_inode->i_block[1] = 0;
4388 } else {
4389 raw_inode->i_block[0] = 0;
4390 raw_inode->i_block[1] =
4391 cpu_to_le32(new_encode_dev(inode->i_rdev));
4392 raw_inode->i_block[2] = 0;
4393 }
4394 } else if (!ext4_has_inline_data(inode)) {
4395 for (block = 0; block < EXT4_N_BLOCKS; block++)
4396 raw_inode->i_block[block] = ei->i_data[block];
4397 }
4398
4399 if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4400 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4401 if (ei->i_extra_isize) {
4402 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4403 raw_inode->i_version_hi =
4404 cpu_to_le32(inode->i_version >> 32);
4405 raw_inode->i_extra_isize =
4406 cpu_to_le16(ei->i_extra_isize);
4407 }
4408 }
4409
4410 ext4_inode_csum_set(inode, raw_inode, ei);
4411
4412 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4413 rc = ext4_handle_dirty_metadata(handle, NULL, bh);
4414 if (!err)
4415 err = rc;
4416 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
4417
4418 ext4_update_inode_fsync_trans(handle, inode, need_datasync);
4419out_brelse:
4420 brelse(bh);
4421 ext4_std_error(inode->i_sb, err);
4422 return err;
4423}
4424
4425/*
4426 * ext4_write_inode()
4427 *
4428 * We are called from a few places:
4429 *
4430 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
4431 * Here, there will be no transaction running. We wait for any running
4432 * transaction to commit.
4433 *
4434 * - Within flush work (sys_sync(), kupdate and such).
4435 * We wait on commit, if told to.
4436 *
4437 * - Within iput_final() -> write_inode_now()
4438 * We wait on commit, if told to.
4439 *
4440 * In all cases it is actually safe for us to return without doing anything,
4441 * because the inode has been copied into a raw inode buffer in
4442 * ext4_mark_inode_dirty(). This is a correctness thing for WB_SYNC_ALL
4443 * writeback.
4444 *
4445 * Note that we are absolutely dependent upon all inode dirtiers doing the
4446 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4447 * which we are interested.
4448 *
4449 * It would be a bug for them to not do this. The code:
4450 *
4451 * mark_inode_dirty(inode)
4452 * stuff();
4453 * inode->i_size = expr;
4454 *
4455 * is in error because write_inode() could occur while `stuff()' is running,
4456 * and the new i_size will be lost. Plus the inode will no longer be on the
4457 * superblock's dirty inode list.
4458 */
4459int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
4460{
4461 int err;
4462
4463 if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
4464 return 0;
4465
4466 if (EXT4_SB(inode->i_sb)->s_journal) {
4467 if (ext4_journal_current_handle()) {
4468 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4469 dump_stack();
4470 return -EIO;
4471 }
4472
4473 /*
4474 * No need to force transaction in WB_SYNC_NONE mode. Also
4475 * ext4_sync_fs() will force the commit after everything is
4476 * written.
4477 */
4478 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
4479 return 0;
4480
4481 err = ext4_force_commit(inode->i_sb);
4482 } else {
4483 struct ext4_iloc iloc;
4484
4485 err = __ext4_get_inode_loc(inode, &iloc, 0);
4486 if (err)
4487 return err;
4488 /*
4489 * sync(2) will flush the whole buffer cache. No need to do
4490 * it here separately for each inode.
4491 */
4492 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
4493 sync_dirty_buffer(iloc.bh);
4494 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
4495 EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
4496 "IO error syncing inode");
4497 err = -EIO;
4498 }
4499 brelse(iloc.bh);
4500 }
4501 return err;
4502}
4503
4504/*
4505 * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
4506 * buffers that are attached to a page stradding i_size and are undergoing
4507 * commit. In that case we have to wait for commit to finish and try again.
4508 */
4509static void ext4_wait_for_tail_page_commit(struct inode *inode)
4510{
4511 struct page *page;
4512 unsigned offset;
4513 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
4514 tid_t commit_tid = 0;
4515 int ret;
4516
4517 offset = inode->i_size & (PAGE_CACHE_SIZE - 1);
4518 /*
4519 * All buffers in the last page remain valid? Then there's nothing to
4520 * do. We do the check mainly to optimize the common PAGE_CACHE_SIZE ==
4521 * blocksize case
4522 */
4523 if (offset > PAGE_CACHE_SIZE - (1 << inode->i_blkbits))
4524 return;
4525 while (1) {
4526 page = find_lock_page(inode->i_mapping,
4527 inode->i_size >> PAGE_CACHE_SHIFT);
4528 if (!page)
4529 return;
4530 ret = __ext4_journalled_invalidatepage(page, offset,
4531 PAGE_CACHE_SIZE - offset);
4532 unlock_page(page);
4533 page_cache_release(page);
4534 if (ret != -EBUSY)
4535 return;
4536 commit_tid = 0;
4537 read_lock(&journal->j_state_lock);
4538 if (journal->j_committing_transaction)
4539 commit_tid = journal->j_committing_transaction->t_tid;
4540 read_unlock(&journal->j_state_lock);
4541 if (commit_tid)
4542 jbd2_log_wait_commit(journal, commit_tid);
4543 }
4544}
4545
4546/*
4547 * ext4_setattr()
4548 *
4549 * Called from notify_change.
4550 *
4551 * We want to trap VFS attempts to truncate the file as soon as
4552 * possible. In particular, we want to make sure that when the VFS
4553 * shrinks i_size, we put the inode on the orphan list and modify
4554 * i_disksize immediately, so that during the subsequent flushing of
4555 * dirty pages and freeing of disk blocks, we can guarantee that any
4556 * commit will leave the blocks being flushed in an unused state on
4557 * disk. (On recovery, the inode will get truncated and the blocks will
4558 * be freed, so we have a strong guarantee that no future commit will
4559 * leave these blocks visible to the user.)
4560 *
4561 * Another thing we have to assure is that if we are in ordered mode
4562 * and inode is still attached to the committing transaction, we must
4563 * we start writeout of all the dirty pages which are being truncated.
4564 * This way we are sure that all the data written in the previous
4565 * transaction are already on disk (truncate waits for pages under
4566 * writeback).
4567 *
4568 * Called with inode->i_mutex down.
4569 */
4570int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4571{
4572 struct inode *inode = dentry->d_inode;
4573 int error, rc = 0;
4574 int orphan = 0;
4575 const unsigned int ia_valid = attr->ia_valid;
4576
4577 error = inode_change_ok(inode, attr);
4578 if (error)
4579 return error;
4580
4581 if (is_quota_modification(inode, attr))
4582 dquot_initialize(inode);
4583 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
4584 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
4585 handle_t *handle;
4586
4587 /* (user+group)*(old+new) structure, inode write (sb,
4588 * inode block, ? - but truncate inode update has it) */
4589 handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
4590 (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
4591 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
4592 if (IS_ERR(handle)) {
4593 error = PTR_ERR(handle);
4594 goto err_out;
4595 }
4596 error = dquot_transfer(inode, attr);
4597 if (error) {
4598 ext4_journal_stop(handle);
4599 return error;
4600 }
4601 /* Update corresponding info in inode so that everything is in
4602 * one transaction */
4603 if (attr->ia_valid & ATTR_UID)
4604 inode->i_uid = attr->ia_uid;
4605 if (attr->ia_valid & ATTR_GID)
4606 inode->i_gid = attr->ia_gid;
4607 error = ext4_mark_inode_dirty(handle, inode);
4608 ext4_journal_stop(handle);
4609 }
4610
4611 if (attr->ia_valid & ATTR_SIZE && attr->ia_size != inode->i_size) {
4612 handle_t *handle;
4613
4614 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4615 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4616
4617 if (attr->ia_size > sbi->s_bitmap_maxbytes)
4618 return -EFBIG;
4619 }
4620
4621 if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
4622 inode_inc_iversion(inode);
4623
4624 if (S_ISREG(inode->i_mode) &&
4625 (attr->ia_size < inode->i_size)) {
4626 if (ext4_should_order_data(inode)) {
4627 error = ext4_begin_ordered_truncate(inode,
4628 attr->ia_size);
4629 if (error)
4630 goto err_out;
4631 }
4632 handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
4633 if (IS_ERR(handle)) {
4634 error = PTR_ERR(handle);
4635 goto err_out;
4636 }
4637 if (ext4_handle_valid(handle)) {
4638 error = ext4_orphan_add(handle, inode);
4639 orphan = 1;
4640 }
4641 down_write(&EXT4_I(inode)->i_data_sem);
4642 EXT4_I(inode)->i_disksize = attr->ia_size;
4643 rc = ext4_mark_inode_dirty(handle, inode);
4644 if (!error)
4645 error = rc;
4646 /*
4647 * We have to update i_size under i_data_sem together
4648 * with i_disksize to avoid races with writeback code
4649 * running ext4_wb_update_i_disksize().
4650 */
4651 if (!error)
4652 i_size_write(inode, attr->ia_size);
4653 up_write(&EXT4_I(inode)->i_data_sem);
4654 ext4_journal_stop(handle);
4655 if (error) {
4656 ext4_orphan_del(NULL, inode);
4657 goto err_out;
4658 }
4659 } else
4660 i_size_write(inode, attr->ia_size);
4661
4662 /*
4663 * Blocks are going to be removed from the inode. Wait
4664 * for dio in flight. Temporarily disable
4665 * dioread_nolock to prevent livelock.
4666 */
4667 if (orphan) {
4668 if (!ext4_should_journal_data(inode)) {
4669 ext4_inode_block_unlocked_dio(inode);
4670 inode_dio_wait(inode);
4671 ext4_inode_resume_unlocked_dio(inode);
4672 } else
4673 ext4_wait_for_tail_page_commit(inode);
4674 }
4675 /*
4676 * Truncate pagecache after we've waited for commit
4677 * in data=journal mode to make pages freeable.
4678 */
4679 truncate_pagecache(inode, inode->i_size);
4680 }
4681 /*
4682 * We want to call ext4_truncate() even if attr->ia_size ==
4683 * inode->i_size for cases like truncation of fallocated space
4684 */
4685 if (attr->ia_valid & ATTR_SIZE)
4686 ext4_truncate(inode);
4687
4688 if (!rc) {
4689 setattr_copy(inode, attr);
4690 mark_inode_dirty(inode);
4691 }
4692
4693 /*
4694 * If the call to ext4_truncate failed to get a transaction handle at
4695 * all, we need to clean up the in-core orphan list manually.
4696 */
4697 if (orphan && inode->i_nlink)
4698 ext4_orphan_del(NULL, inode);
4699
4700 if (!rc && (ia_valid & ATTR_MODE))
4701 rc = posix_acl_chmod(inode, inode->i_mode);
4702
4703err_out:
4704 ext4_std_error(inode->i_sb, error);
4705 if (!error)
4706 error = rc;
4707 return error;
4708}
4709
4710int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
4711 struct kstat *stat)
4712{
4713 struct inode *inode;
4714 unsigned long long delalloc_blocks;
4715
4716 inode = dentry->d_inode;
4717 generic_fillattr(inode, stat);
4718
4719 /*
4720 * If there is inline data in the inode, the inode will normally not
4721 * have data blocks allocated (it may have an external xattr block).
4722 * Report at least one sector for such files, so tools like tar, rsync,
4723 * others doen't incorrectly think the file is completely sparse.
4724 */
4725 if (unlikely(ext4_has_inline_data(inode)))
4726 stat->blocks += (stat->size + 511) >> 9;
4727
4728 /*
4729 * We can't update i_blocks if the block allocation is delayed
4730 * otherwise in the case of system crash before the real block
4731 * allocation is done, we will have i_blocks inconsistent with
4732 * on-disk file blocks.
4733 * We always keep i_blocks updated together with real
4734 * allocation. But to not confuse with user, stat
4735 * will return the blocks that include the delayed allocation
4736 * blocks for this file.
4737 */
4738 delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
4739 EXT4_I(inode)->i_reserved_data_blocks);
4740 stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
4741 return 0;
4742}
4743
4744static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
4745 int pextents)
4746{
4747 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4748 return ext4_ind_trans_blocks(inode, lblocks);
4749 return ext4_ext_index_trans_blocks(inode, pextents);
4750}
4751
4752/*
4753 * Account for index blocks, block groups bitmaps and block group
4754 * descriptor blocks if modify datablocks and index blocks
4755 * worse case, the indexs blocks spread over different block groups
4756 *
4757 * If datablocks are discontiguous, they are possible to spread over
4758 * different block groups too. If they are contiguous, with flexbg,
4759 * they could still across block group boundary.
4760 *
4761 * Also account for superblock, inode, quota and xattr blocks
4762 */
4763static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
4764 int pextents)
4765{
4766 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
4767 int gdpblocks;
4768 int idxblocks;
4769 int ret = 0;
4770
4771 /*
4772 * How many index blocks need to touch to map @lblocks logical blocks
4773 * to @pextents physical extents?
4774 */
4775 idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
4776
4777 ret = idxblocks;
4778
4779 /*
4780 * Now let's see how many group bitmaps and group descriptors need
4781 * to account
4782 */
4783 groups = idxblocks + pextents;
4784 gdpblocks = groups;
4785 if (groups > ngroups)
4786 groups = ngroups;
4787 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
4788 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
4789
4790 /* bitmaps and block group descriptor blocks */
4791 ret += groups + gdpblocks;
4792
4793 /* Blocks for super block, inode, quota and xattr blocks */
4794 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
4795
4796 return ret;
4797}
4798
4799/*
4800 * Calculate the total number of credits to reserve to fit
4801 * the modification of a single pages into a single transaction,
4802 * which may include multiple chunks of block allocations.
4803 *
4804 * This could be called via ext4_write_begin()
4805 *
4806 * We need to consider the worse case, when
4807 * one new block per extent.
4808 */
4809int ext4_writepage_trans_blocks(struct inode *inode)
4810{
4811 int bpp = ext4_journal_blocks_per_page(inode);
4812 int ret;
4813
4814 ret = ext4_meta_trans_blocks(inode, bpp, bpp);
4815
4816 /* Account for data blocks for journalled mode */
4817 if (ext4_should_journal_data(inode))
4818 ret += bpp;
4819 return ret;
4820}
4821
4822/*
4823 * Calculate the journal credits for a chunk of data modification.
4824 *
4825 * This is called from DIO, fallocate or whoever calling
4826 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
4827 *
4828 * journal buffers for data blocks are not included here, as DIO
4829 * and fallocate do no need to journal data buffers.
4830 */
4831int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
4832{
4833 return ext4_meta_trans_blocks(inode, nrblocks, 1);
4834}
4835
4836/*
4837 * The caller must have previously called ext4_reserve_inode_write().
4838 * Give this, we know that the caller already has write access to iloc->bh.
4839 */
4840int ext4_mark_iloc_dirty(handle_t *handle,
4841 struct inode *inode, struct ext4_iloc *iloc)
4842{
4843 int err = 0;
4844
4845 if (IS_I_VERSION(inode))
4846 inode_inc_iversion(inode);
4847
4848 /* the do_update_inode consumes one bh->b_count */
4849 get_bh(iloc->bh);
4850
4851 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4852 err = ext4_do_update_inode(handle, inode, iloc);
4853 put_bh(iloc->bh);
4854 return err;
4855}
4856
4857/*
4858 * On success, We end up with an outstanding reference count against
4859 * iloc->bh. This _must_ be cleaned up later.
4860 */
4861
4862int
4863ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
4864 struct ext4_iloc *iloc)
4865{
4866 int err;
4867
4868 err = ext4_get_inode_loc(inode, iloc);
4869 if (!err) {
4870 BUFFER_TRACE(iloc->bh, "get_write_access");
4871 err = ext4_journal_get_write_access(handle, iloc->bh);
4872 if (err) {
4873 brelse(iloc->bh);
4874 iloc->bh = NULL;
4875 }
4876 }
4877 ext4_std_error(inode->i_sb, err);
4878 return err;
4879}
4880
4881/*
4882 * Expand an inode by new_extra_isize bytes.
4883 * Returns 0 on success or negative error number on failure.
4884 */
4885static int ext4_expand_extra_isize(struct inode *inode,
4886 unsigned int new_extra_isize,
4887 struct ext4_iloc iloc,
4888 handle_t *handle)
4889{
4890 struct ext4_inode *raw_inode;
4891 struct ext4_xattr_ibody_header *header;
4892
4893 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
4894 return 0;
4895
4896 raw_inode = ext4_raw_inode(&iloc);
4897
4898 header = IHDR(inode, raw_inode);
4899
4900 /* No extended attributes present */
4901 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
4902 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
4903 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
4904 new_extra_isize);
4905 EXT4_I(inode)->i_extra_isize = new_extra_isize;
4906 return 0;
4907 }
4908
4909 /* try to expand with EAs present */
4910 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
4911 raw_inode, handle);
4912}
4913
4914/*
4915 * What we do here is to mark the in-core inode as clean with respect to inode
4916 * dirtiness (it may still be data-dirty).
4917 * This means that the in-core inode may be reaped by prune_icache
4918 * without having to perform any I/O. This is a very good thing,
4919 * because *any* task may call prune_icache - even ones which
4920 * have a transaction open against a different journal.
4921 *
4922 * Is this cheating? Not really. Sure, we haven't written the
4923 * inode out, but prune_icache isn't a user-visible syncing function.
4924 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
4925 * we start and wait on commits.
4926 */
4927int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4928{
4929 struct ext4_iloc iloc;
4930 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4931 static unsigned int mnt_count;
4932 int err, ret;
4933
4934 might_sleep();
4935 trace_ext4_mark_inode_dirty(inode, _RET_IP_);
4936 err = ext4_reserve_inode_write(handle, inode, &iloc);
4937 if (ext4_handle_valid(handle) &&
4938 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
4939 !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
4940 /*
4941 * We need extra buffer credits since we may write into EA block
4942 * with this same handle. If journal_extend fails, then it will
4943 * only result in a minor loss of functionality for that inode.
4944 * If this is felt to be critical, then e2fsck should be run to
4945 * force a large enough s_min_extra_isize.
4946 */
4947 if ((jbd2_journal_extend(handle,
4948 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
4949 ret = ext4_expand_extra_isize(inode,
4950 sbi->s_want_extra_isize,
4951 iloc, handle);
4952 if (ret) {
4953 ext4_set_inode_state(inode,
4954 EXT4_STATE_NO_EXPAND);
4955 if (mnt_count !=
4956 le16_to_cpu(sbi->s_es->s_mnt_count)) {
4957 ext4_warning(inode->i_sb,
4958 "Unable to expand inode %lu. Delete"
4959 " some EAs or run e2fsck.",
4960 inode->i_ino);
4961 mnt_count =
4962 le16_to_cpu(sbi->s_es->s_mnt_count);
4963 }
4964 }
4965 }
4966 }
4967 if (!err)
4968 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
4969 return err;
4970}
4971
4972/*
4973 * ext4_dirty_inode() is called from __mark_inode_dirty()
4974 *
4975 * We're really interested in the case where a file is being extended.
4976 * i_size has been changed by generic_commit_write() and we thus need
4977 * to include the updated inode in the current transaction.
4978 *
4979 * Also, dquot_alloc_block() will always dirty the inode when blocks
4980 * are allocated to the file.
4981 *
4982 * If the inode is marked synchronous, we don't honour that here - doing
4983 * so would cause a commit on atime updates, which we don't bother doing.
4984 * We handle synchronous inodes at the highest possible level.
4985 */
4986void ext4_dirty_inode(struct inode *inode, int flags)
4987{
4988 handle_t *handle;
4989
4990 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
4991 if (IS_ERR(handle))
4992 goto out;
4993
4994 ext4_mark_inode_dirty(handle, inode);
4995
4996 ext4_journal_stop(handle);
4997out:
4998 return;
4999}
5000
5001#if 0
5002/*
5003 * Bind an inode's backing buffer_head into this transaction, to prevent
5004 * it from being flushed to disk early. Unlike
5005 * ext4_reserve_inode_write, this leaves behind no bh reference and
5006 * returns no iloc structure, so the caller needs to repeat the iloc
5007 * lookup to mark the inode dirty later.
5008 */
5009static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5010{
5011 struct ext4_iloc iloc;
5012
5013 int err = 0;
5014 if (handle) {
5015 err = ext4_get_inode_loc(inode, &iloc);
5016 if (!err) {
5017 BUFFER_TRACE(iloc.bh, "get_write_access");
5018 err = jbd2_journal_get_write_access(handle, iloc.bh);
5019 if (!err)
5020 err = ext4_handle_dirty_metadata(handle,
5021 NULL,
5022 iloc.bh);
5023 brelse(iloc.bh);
5024 }
5025 }
5026 ext4_std_error(inode->i_sb, err);
5027 return err;
5028}
5029#endif
5030
5031int ext4_change_inode_journal_flag(struct inode *inode, int val)
5032{
5033 journal_t *journal;
5034 handle_t *handle;
5035 int err;
5036
5037 /*
5038 * We have to be very careful here: changing a data block's
5039 * journaling status dynamically is dangerous. If we write a
5040 * data block to the journal, change the status and then delete
5041 * that block, we risk forgetting to revoke the old log record
5042 * from the journal and so a subsequent replay can corrupt data.
5043 * So, first we make sure that the journal is empty and that
5044 * nobody is changing anything.
5045 */
5046
5047 journal = EXT4_JOURNAL(inode);
5048 if (!journal)
5049 return 0;
5050 if (is_journal_aborted(journal))
5051 return -EROFS;
5052 /* We have to allocate physical blocks for delalloc blocks
5053 * before flushing journal. otherwise delalloc blocks can not
5054 * be allocated any more. even more truncate on delalloc blocks
5055 * could trigger BUG by flushing delalloc blocks in journal.
5056 * There is no delalloc block in non-journal data mode.
5057 */
5058 if (val && test_opt(inode->i_sb, DELALLOC)) {
5059 err = ext4_alloc_da_blocks(inode);
5060 if (err < 0)
5061 return err;
5062 }
5063
5064 /* Wait for all existing dio workers */
5065 ext4_inode_block_unlocked_dio(inode);
5066 inode_dio_wait(inode);
5067
5068 jbd2_journal_lock_updates(journal);
5069
5070 /*
5071 * OK, there are no updates running now, and all cached data is
5072 * synced to disk. We are now in a completely consistent state
5073 * which doesn't have anything in the journal, and we know that
5074 * no filesystem updates are running, so it is safe to modify
5075 * the inode's in-core data-journaling state flag now.
5076 */
5077
5078 if (val)
5079 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5080 else {
5081 jbd2_journal_flush(journal);
5082 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5083 }
5084 ext4_set_aops(inode);
5085
5086 jbd2_journal_unlock_updates(journal);
5087 ext4_inode_resume_unlocked_dio(inode);
5088
5089 /* Finally we can mark the inode as dirty. */
5090
5091 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
5092 if (IS_ERR(handle))
5093 return PTR_ERR(handle);
5094
5095 err = ext4_mark_inode_dirty(handle, inode);
5096 ext4_handle_sync(handle);
5097 ext4_journal_stop(handle);
5098 ext4_std_error(inode->i_sb, err);
5099
5100 return err;
5101}
5102
5103static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5104{
5105 return !buffer_mapped(bh);
5106}
5107
5108int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5109{
5110 struct page *page = vmf->page;
5111 loff_t size;
5112 unsigned long len;
5113 int ret;
5114 struct file *file = vma->vm_file;
5115 struct inode *inode = file_inode(file);
5116 struct address_space *mapping = inode->i_mapping;
5117 handle_t *handle;
5118 get_block_t *get_block;
5119 int retries = 0;
5120
5121 sb_start_pagefault(inode->i_sb);
5122 file_update_time(vma->vm_file);
5123 /* Delalloc case is easy... */
5124 if (test_opt(inode->i_sb, DELALLOC) &&
5125 !ext4_should_journal_data(inode) &&
5126 !ext4_nonda_switch(inode->i_sb)) {
5127 do {
5128 ret = __block_page_mkwrite(vma, vmf,
5129 ext4_da_get_block_prep);
5130 } while (ret == -ENOSPC &&
5131 ext4_should_retry_alloc(inode->i_sb, &retries));
5132 goto out_ret;
5133 }
5134
5135 lock_page(page);
5136 size = i_size_read(inode);
5137 /* Page got truncated from under us? */
5138 if (page->mapping != mapping || page_offset(page) > size) {
5139 unlock_page(page);
5140 ret = VM_FAULT_NOPAGE;
5141 goto out;
5142 }
5143
5144 if (page->index == size >> PAGE_CACHE_SHIFT)
5145 len = size & ~PAGE_CACHE_MASK;
5146 else
5147 len = PAGE_CACHE_SIZE;
5148 /*
5149 * Return if we have all the buffers mapped. This avoids the need to do
5150 * journal_start/journal_stop which can block and take a long time
5151 */
5152 if (page_has_buffers(page)) {
5153 if (!ext4_walk_page_buffers(NULL, page_buffers(page),
5154 0, len, NULL,
5155 ext4_bh_unmapped)) {
5156 /* Wait so that we don't change page under IO */
5157 wait_for_stable_page(page);
5158 ret = VM_FAULT_LOCKED;
5159 goto out;
5160 }
5161 }
5162 unlock_page(page);
5163 /* OK, we need to fill the hole... */
5164 if (ext4_should_dioread_nolock(inode))
5165 get_block = ext4_get_block_write;
5166 else
5167 get_block = ext4_get_block;
5168retry_alloc:
5169 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
5170 ext4_writepage_trans_blocks(inode));
5171 if (IS_ERR(handle)) {
5172 ret = VM_FAULT_SIGBUS;
5173 goto out;
5174 }
5175 ret = __block_page_mkwrite(vma, vmf, get_block);
5176 if (!ret && ext4_should_journal_data(inode)) {
5177 if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
5178 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access)) {
5179 unlock_page(page);
5180 ret = VM_FAULT_SIGBUS;
5181 ext4_journal_stop(handle);
5182 goto out;
5183 }
5184 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
5185 }
5186 ext4_journal_stop(handle);
5187 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
5188 goto retry_alloc;
5189out_ret:
5190 ret = block_page_mkwrite_return(ret);
5191out:
5192 sb_end_pagefault(inode->i_sb);
5193 return ret;
5194}