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/highuid.h>
24 #include <linux/pagemap.h>
25 #include <linux/dax.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/bitops.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
50 static __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 = le16_to_cpu(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 = le16_to_cpu(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 = cpu_to_le16(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 = cpu_to_le16(csum_hi);
73
74 return csum;
75 }
76
77 static 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_metadata_csum(inode->i_sb))
85 return 1;
86
87 provided = le16_to_cpu(raw->i_checksum_lo);
88 calculated = ext4_inode_csum(inode, raw, ei);
89 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
90 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
91 provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
92 else
93 calculated &= 0xFFFF;
94
95 return provided == calculated;
96 }
97
98 static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
99 struct ext4_inode_info *ei)
100 {
101 __u32 csum;
102
103 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
104 cpu_to_le32(EXT4_OS_LINUX) ||
105 !ext4_has_metadata_csum(inode->i_sb))
106 return;
107
108 csum = ext4_inode_csum(inode, raw, ei);
109 raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
110 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
111 EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
112 raw->i_checksum_hi = cpu_to_le16(csum >> 16);
113 }
114
115 static inline int ext4_begin_ordered_truncate(struct inode *inode,
116 loff_t new_size)
117 {
118 trace_ext4_begin_ordered_truncate(inode, new_size);
119 /*
120 * If jinode is zero, then we never opened the file for
121 * writing, so there's no need to call
122 * jbd2_journal_begin_ordered_truncate() since there's no
123 * outstanding writes we need to flush.
124 */
125 if (!EXT4_I(inode)->jinode)
126 return 0;
127 return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
128 EXT4_I(inode)->jinode,
129 new_size);
130 }
131
132 static void ext4_invalidatepage(struct page *page, unsigned int offset,
133 unsigned int length);
134 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
135 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
136 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
137 int pextents);
138
139 /*
140 * Test whether an inode is a fast symlink.
141 */
142 int ext4_inode_is_fast_symlink(struct inode *inode)
143 {
144 int ea_blocks = EXT4_I(inode)->i_file_acl ?
145 EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
146
147 if (ext4_has_inline_data(inode))
148 return 0;
149
150 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
151 }
152
153 /*
154 * Restart the transaction associated with *handle. This does a commit,
155 * so before we call here everything must be consistently dirtied against
156 * this transaction.
157 */
158 int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
159 int nblocks)
160 {
161 int ret;
162
163 /*
164 * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
165 * moment, get_block can be called only for blocks inside i_size since
166 * page cache has been already dropped and writes are blocked by
167 * i_mutex. So we can safely drop the i_data_sem here.
168 */
169 BUG_ON(EXT4_JOURNAL(inode) == NULL);
170 jbd_debug(2, "restarting handle %p\n", handle);
171 up_write(&EXT4_I(inode)->i_data_sem);
172 ret = ext4_journal_restart(handle, nblocks);
173 down_write(&EXT4_I(inode)->i_data_sem);
174 ext4_discard_preallocations(inode);
175
176 return ret;
177 }
178
179 /*
180 * Called at the last iput() if i_nlink is zero.
181 */
182 void ext4_evict_inode(struct inode *inode)
183 {
184 handle_t *handle;
185 int err;
186
187 trace_ext4_evict_inode(inode);
188
189 if (inode->i_nlink) {
190 /*
191 * When journalling data dirty buffers are tracked only in the
192 * journal. So although mm thinks everything is clean and
193 * ready for reaping the inode might still have some pages to
194 * write in the running transaction or waiting to be
195 * checkpointed. Thus calling jbd2_journal_invalidatepage()
196 * (via truncate_inode_pages()) to discard these buffers can
197 * cause data loss. Also even if we did not discard these
198 * buffers, we would have no way to find them after the inode
199 * is reaped and thus user could see stale data if he tries to
200 * read them before the transaction is checkpointed. So be
201 * careful and force everything to disk here... We use
202 * ei->i_datasync_tid to store the newest transaction
203 * containing inode's data.
204 *
205 * Note that directories do not have this problem because they
206 * don't use page cache.
207 */
208 if (inode->i_ino != EXT4_JOURNAL_INO &&
209 ext4_should_journal_data(inode) &&
210 (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
211 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
212 tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
213
214 jbd2_complete_transaction(journal, commit_tid);
215 filemap_write_and_wait(&inode->i_data);
216 }
217 truncate_inode_pages_final(&inode->i_data);
218
219 goto no_delete;
220 }
221
222 if (is_bad_inode(inode))
223 goto no_delete;
224 dquot_initialize(inode);
225
226 if (ext4_should_order_data(inode))
227 ext4_begin_ordered_truncate(inode, 0);
228 truncate_inode_pages_final(&inode->i_data);
229
230 /*
231 * Protect us against freezing - iput() caller didn't have to have any
232 * protection against it
233 */
234 sb_start_intwrite(inode->i_sb);
235 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
236 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 sb_end_intwrite(inode->i_sb);
246 goto no_delete;
247 }
248
249 if (IS_SYNC(inode))
250 ext4_handle_sync(handle);
251 inode->i_size = 0;
252 err = ext4_mark_inode_dirty(handle, inode);
253 if (err) {
254 ext4_warning(inode->i_sb,
255 "couldn't mark inode dirty (err %d)", err);
256 goto stop_handle;
257 }
258 if (inode->i_blocks)
259 ext4_truncate(inode);
260
261 /*
262 * ext4_ext_truncate() doesn't reserve any slop when it
263 * restarts journal transactions; therefore there may not be
264 * enough credits left in the handle to remove the inode from
265 * the orphan list and set the dtime field.
266 */
267 if (!ext4_handle_has_enough_credits(handle, 3)) {
268 err = ext4_journal_extend(handle, 3);
269 if (err > 0)
270 err = ext4_journal_restart(handle, 3);
271 if (err != 0) {
272 ext4_warning(inode->i_sb,
273 "couldn't extend journal (err %d)", err);
274 stop_handle:
275 ext4_journal_stop(handle);
276 ext4_orphan_del(NULL, inode);
277 sb_end_intwrite(inode->i_sb);
278 goto no_delete;
279 }
280 }
281
282 /*
283 * Kill off the orphan record which ext4_truncate created.
284 * AKPM: I think this can be inside the above `if'.
285 * Note that ext4_orphan_del() has to be able to cope with the
286 * deletion of a non-existent orphan - this is because we don't
287 * know if ext4_truncate() actually created an orphan record.
288 * (Well, we could do this if we need to, but heck - it works)
289 */
290 ext4_orphan_del(handle, inode);
291 EXT4_I(inode)->i_dtime = get_seconds();
292
293 /*
294 * One subtle ordering requirement: if anything has gone wrong
295 * (transaction abort, IO errors, whatever), then we can still
296 * do these next steps (the fs will already have been marked as
297 * having errors), but we can't free the inode if the mark_dirty
298 * fails.
299 */
300 if (ext4_mark_inode_dirty(handle, inode))
301 /* If that failed, just do the required in-core inode clear. */
302 ext4_clear_inode(inode);
303 else
304 ext4_free_inode(handle, inode);
305 ext4_journal_stop(handle);
306 sb_end_intwrite(inode->i_sb);
307 return;
308 no_delete:
309 ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
310 }
311
312 #ifdef CONFIG_QUOTA
313 qsize_t *ext4_get_reserved_space(struct inode *inode)
314 {
315 return &EXT4_I(inode)->i_reserved_quota;
316 }
317 #endif
318
319 /*
320 * Called with i_data_sem down, which is important since we can call
321 * ext4_discard_preallocations() from here.
322 */
323 void ext4_da_update_reserve_space(struct inode *inode,
324 int used, int quota_claim)
325 {
326 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
327 struct ext4_inode_info *ei = EXT4_I(inode);
328
329 spin_lock(&ei->i_block_reservation_lock);
330 trace_ext4_da_update_reserve_space(inode, used, quota_claim);
331 if (unlikely(used > ei->i_reserved_data_blocks)) {
332 ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
333 "with only %d reserved data blocks",
334 __func__, inode->i_ino, used,
335 ei->i_reserved_data_blocks);
336 WARN_ON(1);
337 used = ei->i_reserved_data_blocks;
338 }
339
340 /* Update per-inode reservations */
341 ei->i_reserved_data_blocks -= used;
342 percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
343
344 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
345
346 /* Update quota subsystem for data blocks */
347 if (quota_claim)
348 dquot_claim_block(inode, EXT4_C2B(sbi, used));
349 else {
350 /*
351 * We did fallocate with an offset that is already delayed
352 * allocated. So on delayed allocated writeback we should
353 * not re-claim the quota for fallocated blocks.
354 */
355 dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
356 }
357
358 /*
359 * If we have done all the pending block allocations and if
360 * there aren't any writers on the inode, we can discard the
361 * inode's preallocations.
362 */
363 if ((ei->i_reserved_data_blocks == 0) &&
364 (atomic_read(&inode->i_writecount) == 0))
365 ext4_discard_preallocations(inode);
366 }
367
368 static int __check_block_validity(struct inode *inode, const char *func,
369 unsigned int line,
370 struct ext4_map_blocks *map)
371 {
372 if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
373 map->m_len)) {
374 ext4_error_inode(inode, func, line, map->m_pblk,
375 "lblock %lu mapped to illegal pblock "
376 "(length %d)", (unsigned long) map->m_lblk,
377 map->m_len);
378 return -EFSCORRUPTED;
379 }
380 return 0;
381 }
382
383 int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
384 ext4_lblk_t len)
385 {
386 int ret;
387
388 if (ext4_encrypted_inode(inode))
389 return ext4_encrypted_zeroout(inode, lblk, pblk, len);
390
391 ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
392 if (ret > 0)
393 ret = 0;
394
395 return ret;
396 }
397
398 #define check_block_validity(inode, map) \
399 __check_block_validity((inode), __func__, __LINE__, (map))
400
401 #ifdef ES_AGGRESSIVE_TEST
402 static void ext4_map_blocks_es_recheck(handle_t *handle,
403 struct inode *inode,
404 struct ext4_map_blocks *es_map,
405 struct ext4_map_blocks *map,
406 int flags)
407 {
408 int retval;
409
410 map->m_flags = 0;
411 /*
412 * There is a race window that the result is not the same.
413 * e.g. xfstests #223 when dioread_nolock enables. The reason
414 * is that we lookup a block mapping in extent status tree with
415 * out taking i_data_sem. So at the time the unwritten extent
416 * could be converted.
417 */
418 down_read(&EXT4_I(inode)->i_data_sem);
419 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
420 retval = ext4_ext_map_blocks(handle, inode, map, flags &
421 EXT4_GET_BLOCKS_KEEP_SIZE);
422 } else {
423 retval = ext4_ind_map_blocks(handle, inode, map, flags &
424 EXT4_GET_BLOCKS_KEEP_SIZE);
425 }
426 up_read((&EXT4_I(inode)->i_data_sem));
427
428 /*
429 * We don't check m_len because extent will be collpased in status
430 * tree. So the m_len might not equal.
431 */
432 if (es_map->m_lblk != map->m_lblk ||
433 es_map->m_flags != map->m_flags ||
434 es_map->m_pblk != map->m_pblk) {
435 printk("ES cache assertion failed for inode: %lu "
436 "es_cached ex [%d/%d/%llu/%x] != "
437 "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
438 inode->i_ino, es_map->m_lblk, es_map->m_len,
439 es_map->m_pblk, es_map->m_flags, map->m_lblk,
440 map->m_len, map->m_pblk, map->m_flags,
441 retval, flags);
442 }
443 }
444 #endif /* ES_AGGRESSIVE_TEST */
445
446 /*
447 * The ext4_map_blocks() function tries to look up the requested blocks,
448 * and returns if the blocks are already mapped.
449 *
450 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
451 * and store the allocated blocks in the result buffer head and mark it
452 * mapped.
453 *
454 * If file type is extents based, it will call ext4_ext_map_blocks(),
455 * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
456 * based files
457 *
458 * On success, it returns the number of blocks being mapped or allocated. if
459 * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
460 * is marked as unwritten. If the create == 1, it will mark @map as mapped.
461 *
462 * It returns 0 if plain look up failed (blocks have not been allocated), in
463 * that case, @map is returned as unmapped but we still do fill map->m_len to
464 * indicate the length of a hole starting at map->m_lblk.
465 *
466 * It returns the error in case of allocation failure.
467 */
468 int ext4_map_blocks(handle_t *handle, struct inode *inode,
469 struct ext4_map_blocks *map, int flags)
470 {
471 struct extent_status es;
472 int retval;
473 int ret = 0;
474 #ifdef ES_AGGRESSIVE_TEST
475 struct ext4_map_blocks orig_map;
476
477 memcpy(&orig_map, map, sizeof(*map));
478 #endif
479
480 map->m_flags = 0;
481 ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
482 "logical block %lu\n", inode->i_ino, flags, map->m_len,
483 (unsigned long) map->m_lblk);
484
485 /*
486 * ext4_map_blocks returns an int, and m_len is an unsigned int
487 */
488 if (unlikely(map->m_len > INT_MAX))
489 map->m_len = INT_MAX;
490
491 /* We can handle the block number less than EXT_MAX_BLOCKS */
492 if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
493 return -EFSCORRUPTED;
494
495 /* Lookup extent status tree firstly */
496 if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
497 if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
498 map->m_pblk = ext4_es_pblock(&es) +
499 map->m_lblk - es.es_lblk;
500 map->m_flags |= ext4_es_is_written(&es) ?
501 EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
502 retval = es.es_len - (map->m_lblk - es.es_lblk);
503 if (retval > map->m_len)
504 retval = map->m_len;
505 map->m_len = retval;
506 } else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
507 map->m_pblk = 0;
508 retval = es.es_len - (map->m_lblk - es.es_lblk);
509 if (retval > map->m_len)
510 retval = map->m_len;
511 map->m_len = retval;
512 retval = 0;
513 } else {
514 BUG_ON(1);
515 }
516 #ifdef ES_AGGRESSIVE_TEST
517 ext4_map_blocks_es_recheck(handle, inode, map,
518 &orig_map, flags);
519 #endif
520 goto found;
521 }
522
523 /*
524 * Try to see if we can get the block without requesting a new
525 * file system block.
526 */
527 down_read(&EXT4_I(inode)->i_data_sem);
528 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
529 retval = ext4_ext_map_blocks(handle, inode, map, flags &
530 EXT4_GET_BLOCKS_KEEP_SIZE);
531 } else {
532 retval = ext4_ind_map_blocks(handle, inode, map, flags &
533 EXT4_GET_BLOCKS_KEEP_SIZE);
534 }
535 if (retval > 0) {
536 unsigned int status;
537
538 if (unlikely(retval != map->m_len)) {
539 ext4_warning(inode->i_sb,
540 "ES len assertion failed for inode "
541 "%lu: retval %d != map->m_len %d",
542 inode->i_ino, retval, map->m_len);
543 WARN_ON(1);
544 }
545
546 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
547 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
548 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
549 !(status & EXTENT_STATUS_WRITTEN) &&
550 ext4_find_delalloc_range(inode, map->m_lblk,
551 map->m_lblk + map->m_len - 1))
552 status |= EXTENT_STATUS_DELAYED;
553 ret = ext4_es_insert_extent(inode, map->m_lblk,
554 map->m_len, map->m_pblk, status);
555 if (ret < 0)
556 retval = ret;
557 }
558 up_read((&EXT4_I(inode)->i_data_sem));
559
560 found:
561 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
562 ret = check_block_validity(inode, map);
563 if (ret != 0)
564 return ret;
565 }
566
567 /* If it is only a block(s) look up */
568 if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
569 return retval;
570
571 /*
572 * Returns if the blocks have already allocated
573 *
574 * Note that if blocks have been preallocated
575 * ext4_ext_get_block() returns the create = 0
576 * with buffer head unmapped.
577 */
578 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
579 /*
580 * If we need to convert extent to unwritten
581 * we continue and do the actual work in
582 * ext4_ext_map_blocks()
583 */
584 if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
585 return retval;
586
587 /*
588 * Here we clear m_flags because after allocating an new extent,
589 * it will be set again.
590 */
591 map->m_flags &= ~EXT4_MAP_FLAGS;
592
593 /*
594 * New blocks allocate and/or writing to unwritten extent
595 * will possibly result in updating i_data, so we take
596 * the write lock of i_data_sem, and call get_block()
597 * with create == 1 flag.
598 */
599 down_write(&EXT4_I(inode)->i_data_sem);
600
601 /*
602 * We need to check for EXT4 here because migrate
603 * could have changed the inode type in between
604 */
605 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
606 retval = ext4_ext_map_blocks(handle, inode, map, flags);
607 } else {
608 retval = ext4_ind_map_blocks(handle, inode, map, flags);
609
610 if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
611 /*
612 * We allocated new blocks which will result in
613 * i_data's format changing. Force the migrate
614 * to fail by clearing migrate flags
615 */
616 ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
617 }
618
619 /*
620 * Update reserved blocks/metadata blocks after successful
621 * block allocation which had been deferred till now. We don't
622 * support fallocate for non extent files. So we can update
623 * reserve space here.
624 */
625 if ((retval > 0) &&
626 (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
627 ext4_da_update_reserve_space(inode, retval, 1);
628 }
629
630 if (retval > 0) {
631 unsigned int status;
632
633 if (unlikely(retval != map->m_len)) {
634 ext4_warning(inode->i_sb,
635 "ES len assertion failed for inode "
636 "%lu: retval %d != map->m_len %d",
637 inode->i_ino, retval, map->m_len);
638 WARN_ON(1);
639 }
640
641 /*
642 * We have to zeroout blocks before inserting them into extent
643 * status tree. Otherwise someone could look them up there and
644 * use them before they are really zeroed.
645 */
646 if (flags & EXT4_GET_BLOCKS_ZERO &&
647 map->m_flags & EXT4_MAP_MAPPED &&
648 map->m_flags & EXT4_MAP_NEW) {
649 ret = ext4_issue_zeroout(inode, map->m_lblk,
650 map->m_pblk, map->m_len);
651 if (ret) {
652 retval = ret;
653 goto out_sem;
654 }
655 }
656
657 /*
658 * If the extent has been zeroed out, we don't need to update
659 * extent status tree.
660 */
661 if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
662 ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
663 if (ext4_es_is_written(&es))
664 goto out_sem;
665 }
666 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
667 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
668 if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
669 !(status & EXTENT_STATUS_WRITTEN) &&
670 ext4_find_delalloc_range(inode, map->m_lblk,
671 map->m_lblk + map->m_len - 1))
672 status |= EXTENT_STATUS_DELAYED;
673 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
674 map->m_pblk, status);
675 if (ret < 0) {
676 retval = ret;
677 goto out_sem;
678 }
679 }
680
681 out_sem:
682 up_write((&EXT4_I(inode)->i_data_sem));
683 if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
684 ret = check_block_validity(inode, map);
685 if (ret != 0)
686 return ret;
687
688 /*
689 * Inodes with freshly allocated blocks where contents will be
690 * visible after transaction commit must be on transaction's
691 * ordered data list.
692 */
693 if (map->m_flags & EXT4_MAP_NEW &&
694 !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
695 !(flags & EXT4_GET_BLOCKS_ZERO) &&
696 !IS_NOQUOTA(inode) &&
697 ext4_should_order_data(inode)) {
698 ret = ext4_jbd2_file_inode(handle, inode);
699 if (ret)
700 return ret;
701 }
702 }
703 return retval;
704 }
705
706 /*
707 * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
708 * we have to be careful as someone else may be manipulating b_state as well.
709 */
710 static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
711 {
712 unsigned long old_state;
713 unsigned long new_state;
714
715 flags &= EXT4_MAP_FLAGS;
716
717 /* Dummy buffer_head? Set non-atomically. */
718 if (!bh->b_page) {
719 bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
720 return;
721 }
722 /*
723 * Someone else may be modifying b_state. Be careful! This is ugly but
724 * once we get rid of using bh as a container for mapping information
725 * to pass to / from get_block functions, this can go away.
726 */
727 do {
728 old_state = READ_ONCE(bh->b_state);
729 new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
730 } while (unlikely(
731 cmpxchg(&bh->b_state, old_state, new_state) != old_state));
732 }
733
734 static int _ext4_get_block(struct inode *inode, sector_t iblock,
735 struct buffer_head *bh, int flags)
736 {
737 struct ext4_map_blocks map;
738 int ret = 0;
739
740 if (ext4_has_inline_data(inode))
741 return -ERANGE;
742
743 map.m_lblk = iblock;
744 map.m_len = bh->b_size >> inode->i_blkbits;
745
746 ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
747 flags);
748 if (ret > 0) {
749 map_bh(bh, inode->i_sb, map.m_pblk);
750 ext4_update_bh_state(bh, map.m_flags);
751 bh->b_size = inode->i_sb->s_blocksize * map.m_len;
752 ret = 0;
753 }
754 return ret;
755 }
756
757 int ext4_get_block(struct inode *inode, sector_t iblock,
758 struct buffer_head *bh, int create)
759 {
760 return _ext4_get_block(inode, iblock, bh,
761 create ? EXT4_GET_BLOCKS_CREATE : 0);
762 }
763
764 /*
765 * Get block function used when preparing for buffered write if we require
766 * creating an unwritten extent if blocks haven't been allocated. The extent
767 * will be converted to written after the IO is complete.
768 */
769 int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
770 struct buffer_head *bh_result, int create)
771 {
772 ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
773 inode->i_ino, create);
774 return _ext4_get_block(inode, iblock, bh_result,
775 EXT4_GET_BLOCKS_IO_CREATE_EXT);
776 }
777
778 /* Maximum number of blocks we map for direct IO at once. */
779 #define DIO_MAX_BLOCKS 4096
780
781 /*
782 * Get blocks function for the cases that need to start a transaction -
783 * generally difference cases of direct IO and DAX IO. It also handles retries
784 * in case of ENOSPC.
785 */
786 static int ext4_get_block_trans(struct inode *inode, sector_t iblock,
787 struct buffer_head *bh_result, int flags)
788 {
789 int dio_credits;
790 handle_t *handle;
791 int retries = 0;
792 int ret;
793
794 /* Trim mapping request to maximum we can map at once for DIO */
795 if (bh_result->b_size >> inode->i_blkbits > DIO_MAX_BLOCKS)
796 bh_result->b_size = DIO_MAX_BLOCKS << inode->i_blkbits;
797 dio_credits = ext4_chunk_trans_blocks(inode,
798 bh_result->b_size >> inode->i_blkbits);
799 retry:
800 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
801 if (IS_ERR(handle))
802 return PTR_ERR(handle);
803
804 ret = _ext4_get_block(inode, iblock, bh_result, flags);
805 ext4_journal_stop(handle);
806
807 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
808 goto retry;
809 return ret;
810 }
811
812 /* Get block function for DIO reads and writes to inodes without extents */
813 int ext4_dio_get_block(struct inode *inode, sector_t iblock,
814 struct buffer_head *bh, int create)
815 {
816 /* We don't expect handle for direct IO */
817 WARN_ON_ONCE(ext4_journal_current_handle());
818
819 if (!create)
820 return _ext4_get_block(inode, iblock, bh, 0);
821 return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE);
822 }
823
824 /*
825 * Get block function for AIO DIO writes when we create unwritten extent if
826 * blocks are not allocated yet. The extent will be converted to written
827 * after IO is complete.
828 */
829 static int ext4_dio_get_block_unwritten_async(struct inode *inode,
830 sector_t iblock, struct buffer_head *bh_result, int create)
831 {
832 int ret;
833
834 /* We don't expect handle for direct IO */
835 WARN_ON_ONCE(ext4_journal_current_handle());
836
837 ret = ext4_get_block_trans(inode, iblock, bh_result,
838 EXT4_GET_BLOCKS_IO_CREATE_EXT);
839
840 /*
841 * When doing DIO using unwritten extents, we need io_end to convert
842 * unwritten extents to written on IO completion. We allocate io_end
843 * once we spot unwritten extent and store it in b_private. Generic
844 * DIO code keeps b_private set and furthermore passes the value to
845 * our completion callback in 'private' argument.
846 */
847 if (!ret && buffer_unwritten(bh_result)) {
848 if (!bh_result->b_private) {
849 ext4_io_end_t *io_end;
850
851 io_end = ext4_init_io_end(inode, GFP_KERNEL);
852 if (!io_end)
853 return -ENOMEM;
854 bh_result->b_private = io_end;
855 ext4_set_io_unwritten_flag(inode, io_end);
856 }
857 set_buffer_defer_completion(bh_result);
858 }
859
860 return ret;
861 }
862
863 /*
864 * Get block function for non-AIO DIO writes when we create unwritten extent if
865 * blocks are not allocated yet. The extent will be converted to written
866 * after IO is complete from ext4_ext_direct_IO() function.
867 */
868 static int ext4_dio_get_block_unwritten_sync(struct inode *inode,
869 sector_t iblock, struct buffer_head *bh_result, int create)
870 {
871 int ret;
872
873 /* We don't expect handle for direct IO */
874 WARN_ON_ONCE(ext4_journal_current_handle());
875
876 ret = ext4_get_block_trans(inode, iblock, bh_result,
877 EXT4_GET_BLOCKS_IO_CREATE_EXT);
878
879 /*
880 * Mark inode as having pending DIO writes to unwritten extents.
881 * ext4_ext_direct_IO() checks this flag and converts extents to
882 * written.
883 */
884 if (!ret && buffer_unwritten(bh_result))
885 ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
886
887 return ret;
888 }
889
890 static int ext4_dio_get_block_overwrite(struct inode *inode, sector_t iblock,
891 struct buffer_head *bh_result, int create)
892 {
893 int ret;
894
895 ext4_debug("ext4_dio_get_block_overwrite: inode %lu, create flag %d\n",
896 inode->i_ino, create);
897 /* We don't expect handle for direct IO */
898 WARN_ON_ONCE(ext4_journal_current_handle());
899
900 ret = _ext4_get_block(inode, iblock, bh_result, 0);
901 /*
902 * Blocks should have been preallocated! ext4_file_write_iter() checks
903 * that.
904 */
905 WARN_ON_ONCE(!buffer_mapped(bh_result) || buffer_unwritten(bh_result));
906
907 return ret;
908 }
909
910
911 /*
912 * `handle' can be NULL if create is zero
913 */
914 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
915 ext4_lblk_t block, int map_flags)
916 {
917 struct ext4_map_blocks map;
918 struct buffer_head *bh;
919 int create = map_flags & EXT4_GET_BLOCKS_CREATE;
920 int err;
921
922 J_ASSERT(handle != NULL || create == 0);
923
924 map.m_lblk = block;
925 map.m_len = 1;
926 err = ext4_map_blocks(handle, inode, &map, map_flags);
927
928 if (err == 0)
929 return create ? ERR_PTR(-ENOSPC) : NULL;
930 if (err < 0)
931 return ERR_PTR(err);
932
933 bh = sb_getblk(inode->i_sb, map.m_pblk);
934 if (unlikely(!bh))
935 return ERR_PTR(-ENOMEM);
936 if (map.m_flags & EXT4_MAP_NEW) {
937 J_ASSERT(create != 0);
938 J_ASSERT(handle != NULL);
939
940 /*
941 * Now that we do not always journal data, we should
942 * keep in mind whether this should always journal the
943 * new buffer as metadata. For now, regular file
944 * writes use ext4_get_block instead, so it's not a
945 * problem.
946 */
947 lock_buffer(bh);
948 BUFFER_TRACE(bh, "call get_create_access");
949 err = ext4_journal_get_create_access(handle, bh);
950 if (unlikely(err)) {
951 unlock_buffer(bh);
952 goto errout;
953 }
954 if (!buffer_uptodate(bh)) {
955 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
956 set_buffer_uptodate(bh);
957 }
958 unlock_buffer(bh);
959 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
960 err = ext4_handle_dirty_metadata(handle, inode, bh);
961 if (unlikely(err))
962 goto errout;
963 } else
964 BUFFER_TRACE(bh, "not a new buffer");
965 return bh;
966 errout:
967 brelse(bh);
968 return ERR_PTR(err);
969 }
970
971 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
972 ext4_lblk_t block, int map_flags)
973 {
974 struct buffer_head *bh;
975
976 bh = ext4_getblk(handle, inode, block, map_flags);
977 if (IS_ERR(bh))
978 return bh;
979 if (!bh || buffer_uptodate(bh))
980 return bh;
981 ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
982 wait_on_buffer(bh);
983 if (buffer_uptodate(bh))
984 return bh;
985 put_bh(bh);
986 return ERR_PTR(-EIO);
987 }
988
989 int ext4_walk_page_buffers(handle_t *handle,
990 struct buffer_head *head,
991 unsigned from,
992 unsigned to,
993 int *partial,
994 int (*fn)(handle_t *handle,
995 struct buffer_head *bh))
996 {
997 struct buffer_head *bh;
998 unsigned block_start, block_end;
999 unsigned blocksize = head->b_size;
1000 int err, ret = 0;
1001 struct buffer_head *next;
1002
1003 for (bh = head, block_start = 0;
1004 ret == 0 && (bh != head || !block_start);
1005 block_start = block_end, bh = next) {
1006 next = bh->b_this_page;
1007 block_end = block_start + blocksize;
1008 if (block_end <= from || block_start >= to) {
1009 if (partial && !buffer_uptodate(bh))
1010 *partial = 1;
1011 continue;
1012 }
1013 err = (*fn)(handle, bh);
1014 if (!ret)
1015 ret = err;
1016 }
1017 return ret;
1018 }
1019
1020 /*
1021 * To preserve ordering, it is essential that the hole instantiation and
1022 * the data write be encapsulated in a single transaction. We cannot
1023 * close off a transaction and start a new one between the ext4_get_block()
1024 * and the commit_write(). So doing the jbd2_journal_start at the start of
1025 * prepare_write() is the right place.
1026 *
1027 * Also, this function can nest inside ext4_writepage(). In that case, we
1028 * *know* that ext4_writepage() has generated enough buffer credits to do the
1029 * whole page. So we won't block on the journal in that case, which is good,
1030 * because the caller may be PF_MEMALLOC.
1031 *
1032 * By accident, ext4 can be reentered when a transaction is open via
1033 * quota file writes. If we were to commit the transaction while thus
1034 * reentered, there can be a deadlock - we would be holding a quota
1035 * lock, and the commit would never complete if another thread had a
1036 * transaction open and was blocking on the quota lock - a ranking
1037 * violation.
1038 *
1039 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1040 * will _not_ run commit under these circumstances because handle->h_ref
1041 * is elevated. We'll still have enough credits for the tiny quotafile
1042 * write.
1043 */
1044 int do_journal_get_write_access(handle_t *handle,
1045 struct buffer_head *bh)
1046 {
1047 int dirty = buffer_dirty(bh);
1048 int ret;
1049
1050 if (!buffer_mapped(bh) || buffer_freed(bh))
1051 return 0;
1052 /*
1053 * __block_write_begin() could have dirtied some buffers. Clean
1054 * the dirty bit as jbd2_journal_get_write_access() could complain
1055 * otherwise about fs integrity issues. Setting of the dirty bit
1056 * by __block_write_begin() isn't a real problem here as we clear
1057 * the bit before releasing a page lock and thus writeback cannot
1058 * ever write the buffer.
1059 */
1060 if (dirty)
1061 clear_buffer_dirty(bh);
1062 BUFFER_TRACE(bh, "get write access");
1063 ret = ext4_journal_get_write_access(handle, bh);
1064 if (!ret && dirty)
1065 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1066 return ret;
1067 }
1068
1069 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1070 static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1071 get_block_t *get_block)
1072 {
1073 unsigned from = pos & (PAGE_SIZE - 1);
1074 unsigned to = from + len;
1075 struct inode *inode = page->mapping->host;
1076 unsigned block_start, block_end;
1077 sector_t block;
1078 int err = 0;
1079 unsigned blocksize = inode->i_sb->s_blocksize;
1080 unsigned bbits;
1081 struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
1082 bool decrypt = false;
1083
1084 BUG_ON(!PageLocked(page));
1085 BUG_ON(from > PAGE_SIZE);
1086 BUG_ON(to > PAGE_SIZE);
1087 BUG_ON(from > to);
1088
1089 if (!page_has_buffers(page))
1090 create_empty_buffers(page, blocksize, 0);
1091 head = page_buffers(page);
1092 bbits = ilog2(blocksize);
1093 block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1094
1095 for (bh = head, block_start = 0; bh != head || !block_start;
1096 block++, block_start = block_end, bh = bh->b_this_page) {
1097 block_end = block_start + blocksize;
1098 if (block_end <= from || block_start >= to) {
1099 if (PageUptodate(page)) {
1100 if (!buffer_uptodate(bh))
1101 set_buffer_uptodate(bh);
1102 }
1103 continue;
1104 }
1105 if (buffer_new(bh))
1106 clear_buffer_new(bh);
1107 if (!buffer_mapped(bh)) {
1108 WARN_ON(bh->b_size != blocksize);
1109 err = get_block(inode, block, bh, 1);
1110 if (err)
1111 break;
1112 if (buffer_new(bh)) {
1113 unmap_underlying_metadata(bh->b_bdev,
1114 bh->b_blocknr);
1115 if (PageUptodate(page)) {
1116 clear_buffer_new(bh);
1117 set_buffer_uptodate(bh);
1118 mark_buffer_dirty(bh);
1119 continue;
1120 }
1121 if (block_end > to || block_start < from)
1122 zero_user_segments(page, to, block_end,
1123 block_start, from);
1124 continue;
1125 }
1126 }
1127 if (PageUptodate(page)) {
1128 if (!buffer_uptodate(bh))
1129 set_buffer_uptodate(bh);
1130 continue;
1131 }
1132 if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1133 !buffer_unwritten(bh) &&
1134 (block_start < from || block_end > to)) {
1135 ll_rw_block(READ, 1, &bh);
1136 *wait_bh++ = bh;
1137 decrypt = ext4_encrypted_inode(inode) &&
1138 S_ISREG(inode->i_mode);
1139 }
1140 }
1141 /*
1142 * If we issued read requests, let them complete.
1143 */
1144 while (wait_bh > wait) {
1145 wait_on_buffer(*--wait_bh);
1146 if (!buffer_uptodate(*wait_bh))
1147 err = -EIO;
1148 }
1149 if (unlikely(err))
1150 page_zero_new_buffers(page, from, to);
1151 else if (decrypt)
1152 err = ext4_decrypt(page);
1153 return err;
1154 }
1155 #endif
1156
1157 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1158 loff_t pos, unsigned len, unsigned flags,
1159 struct page **pagep, void **fsdata)
1160 {
1161 struct inode *inode = mapping->host;
1162 int ret, needed_blocks;
1163 handle_t *handle;
1164 int retries = 0;
1165 struct page *page;
1166 pgoff_t index;
1167 unsigned from, to;
1168
1169 trace_ext4_write_begin(inode, pos, len, flags);
1170 /*
1171 * Reserve one block more for addition to orphan list in case
1172 * we allocate blocks but write fails for some reason
1173 */
1174 needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1175 index = pos >> PAGE_SHIFT;
1176 from = pos & (PAGE_SIZE - 1);
1177 to = from + len;
1178
1179 if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1180 ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1181 flags, pagep);
1182 if (ret < 0)
1183 return ret;
1184 if (ret == 1)
1185 return 0;
1186 }
1187
1188 /*
1189 * grab_cache_page_write_begin() can take a long time if the
1190 * system is thrashing due to memory pressure, or if the page
1191 * is being written back. So grab it first before we start
1192 * the transaction handle. This also allows us to allocate
1193 * the page (if needed) without using GFP_NOFS.
1194 */
1195 retry_grab:
1196 page = grab_cache_page_write_begin(mapping, index, flags);
1197 if (!page)
1198 return -ENOMEM;
1199 unlock_page(page);
1200
1201 retry_journal:
1202 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1203 if (IS_ERR(handle)) {
1204 put_page(page);
1205 return PTR_ERR(handle);
1206 }
1207
1208 lock_page(page);
1209 if (page->mapping != mapping) {
1210 /* The page got truncated from under us */
1211 unlock_page(page);
1212 put_page(page);
1213 ext4_journal_stop(handle);
1214 goto retry_grab;
1215 }
1216 /* In case writeback began while the page was unlocked */
1217 wait_for_stable_page(page);
1218
1219 #ifdef CONFIG_EXT4_FS_ENCRYPTION
1220 if (ext4_should_dioread_nolock(inode))
1221 ret = ext4_block_write_begin(page, pos, len,
1222 ext4_get_block_unwritten);
1223 else
1224 ret = ext4_block_write_begin(page, pos, len,
1225 ext4_get_block);
1226 #else
1227 if (ext4_should_dioread_nolock(inode))
1228 ret = __block_write_begin(page, pos, len,
1229 ext4_get_block_unwritten);
1230 else
1231 ret = __block_write_begin(page, pos, len, ext4_get_block);
1232 #endif
1233 if (!ret && ext4_should_journal_data(inode)) {
1234 ret = ext4_walk_page_buffers(handle, page_buffers(page),
1235 from, to, NULL,
1236 do_journal_get_write_access);
1237 }
1238
1239 if (ret) {
1240 unlock_page(page);
1241 /*
1242 * __block_write_begin may have instantiated a few blocks
1243 * outside i_size. Trim these off again. Don't need
1244 * i_size_read because we hold i_mutex.
1245 *
1246 * Add inode to orphan list in case we crash before
1247 * truncate finishes
1248 */
1249 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1250 ext4_orphan_add(handle, inode);
1251
1252 ext4_journal_stop(handle);
1253 if (pos + len > inode->i_size) {
1254 ext4_truncate_failed_write(inode);
1255 /*
1256 * If truncate failed early the inode might
1257 * still be on the orphan list; we need to
1258 * make sure the inode is removed from the
1259 * orphan list in that case.
1260 */
1261 if (inode->i_nlink)
1262 ext4_orphan_del(NULL, inode);
1263 }
1264
1265 if (ret == -ENOSPC &&
1266 ext4_should_retry_alloc(inode->i_sb, &retries))
1267 goto retry_journal;
1268 put_page(page);
1269 return ret;
1270 }
1271 *pagep = page;
1272 return ret;
1273 }
1274
1275 /* For write_end() in data=journal mode */
1276 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1277 {
1278 int ret;
1279 if (!buffer_mapped(bh) || buffer_freed(bh))
1280 return 0;
1281 set_buffer_uptodate(bh);
1282 ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1283 clear_buffer_meta(bh);
1284 clear_buffer_prio(bh);
1285 return ret;
1286 }
1287
1288 /*
1289 * We need to pick up the new inode size which generic_commit_write gave us
1290 * `file' can be NULL - eg, when called from page_symlink().
1291 *
1292 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1293 * buffers are managed internally.
1294 */
1295 static int ext4_write_end(struct file *file,
1296 struct address_space *mapping,
1297 loff_t pos, unsigned len, unsigned copied,
1298 struct page *page, void *fsdata)
1299 {
1300 handle_t *handle = ext4_journal_current_handle();
1301 struct inode *inode = mapping->host;
1302 loff_t old_size = inode->i_size;
1303 int ret = 0, ret2;
1304 int i_size_changed = 0;
1305
1306 trace_ext4_write_end(inode, pos, len, copied);
1307 if (ext4_has_inline_data(inode)) {
1308 ret = ext4_write_inline_data_end(inode, pos, len,
1309 copied, page);
1310 if (ret < 0)
1311 goto errout;
1312 copied = ret;
1313 } else
1314 copied = block_write_end(file, mapping, pos,
1315 len, copied, page, fsdata);
1316 /*
1317 * it's important to update i_size while still holding page lock:
1318 * page writeout could otherwise come in and zero beyond i_size.
1319 */
1320 i_size_changed = ext4_update_inode_size(inode, pos + copied);
1321 unlock_page(page);
1322 put_page(page);
1323
1324 if (old_size < pos)
1325 pagecache_isize_extended(inode, old_size, pos);
1326 /*
1327 * Don't mark the inode dirty under page lock. First, it unnecessarily
1328 * makes the holding time of page lock longer. Second, it forces lock
1329 * ordering of page lock and transaction start for journaling
1330 * filesystems.
1331 */
1332 if (i_size_changed)
1333 ext4_mark_inode_dirty(handle, inode);
1334
1335 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1336 /* if we have allocated more blocks and copied
1337 * less. We will have blocks allocated outside
1338 * inode->i_size. So truncate them
1339 */
1340 ext4_orphan_add(handle, inode);
1341 errout:
1342 ret2 = ext4_journal_stop(handle);
1343 if (!ret)
1344 ret = ret2;
1345
1346 if (pos + len > inode->i_size) {
1347 ext4_truncate_failed_write(inode);
1348 /*
1349 * If truncate failed early the inode might still be
1350 * on the orphan list; we need to make sure the inode
1351 * is removed from the orphan list in that case.
1352 */
1353 if (inode->i_nlink)
1354 ext4_orphan_del(NULL, inode);
1355 }
1356
1357 return ret ? ret : copied;
1358 }
1359
1360 /*
1361 * This is a private version of page_zero_new_buffers() which doesn't
1362 * set the buffer to be dirty, since in data=journalled mode we need
1363 * to call ext4_handle_dirty_metadata() instead.
1364 */
1365 static void zero_new_buffers(struct page *page, unsigned from, unsigned to)
1366 {
1367 unsigned int block_start = 0, block_end;
1368 struct buffer_head *head, *bh;
1369
1370 bh = head = page_buffers(page);
1371 do {
1372 block_end = block_start + bh->b_size;
1373 if (buffer_new(bh)) {
1374 if (block_end > from && block_start < to) {
1375 if (!PageUptodate(page)) {
1376 unsigned start, size;
1377
1378 start = max(from, block_start);
1379 size = min(to, block_end) - start;
1380
1381 zero_user(page, start, size);
1382 set_buffer_uptodate(bh);
1383 }
1384 clear_buffer_new(bh);
1385 }
1386 }
1387 block_start = block_end;
1388 bh = bh->b_this_page;
1389 } while (bh != head);
1390 }
1391
1392 static int ext4_journalled_write_end(struct file *file,
1393 struct address_space *mapping,
1394 loff_t pos, unsigned len, unsigned copied,
1395 struct page *page, void *fsdata)
1396 {
1397 handle_t *handle = ext4_journal_current_handle();
1398 struct inode *inode = mapping->host;
1399 loff_t old_size = inode->i_size;
1400 int ret = 0, ret2;
1401 int partial = 0;
1402 unsigned from, to;
1403 int size_changed = 0;
1404
1405 trace_ext4_journalled_write_end(inode, pos, len, copied);
1406 from = pos & (PAGE_SIZE - 1);
1407 to = from + len;
1408
1409 BUG_ON(!ext4_handle_valid(handle));
1410
1411 if (ext4_has_inline_data(inode))
1412 copied = ext4_write_inline_data_end(inode, pos, len,
1413 copied, page);
1414 else {
1415 if (copied < len) {
1416 if (!PageUptodate(page))
1417 copied = 0;
1418 zero_new_buffers(page, from+copied, to);
1419 }
1420
1421 ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
1422 to, &partial, write_end_fn);
1423 if (!partial)
1424 SetPageUptodate(page);
1425 }
1426 size_changed = ext4_update_inode_size(inode, pos + copied);
1427 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1428 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1429 unlock_page(page);
1430 put_page(page);
1431
1432 if (old_size < pos)
1433 pagecache_isize_extended(inode, old_size, pos);
1434
1435 if (size_changed) {
1436 ret2 = ext4_mark_inode_dirty(handle, inode);
1437 if (!ret)
1438 ret = ret2;
1439 }
1440
1441 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1442 /* if we have allocated more blocks and copied
1443 * less. We will have blocks allocated outside
1444 * inode->i_size. So truncate them
1445 */
1446 ext4_orphan_add(handle, inode);
1447
1448 ret2 = ext4_journal_stop(handle);
1449 if (!ret)
1450 ret = ret2;
1451 if (pos + len > inode->i_size) {
1452 ext4_truncate_failed_write(inode);
1453 /*
1454 * If truncate failed early the inode might still be
1455 * on the orphan list; we need to make sure the inode
1456 * is removed from the orphan list in that case.
1457 */
1458 if (inode->i_nlink)
1459 ext4_orphan_del(NULL, inode);
1460 }
1461
1462 return ret ? ret : copied;
1463 }
1464
1465 /*
1466 * Reserve space for a single cluster
1467 */
1468 static int ext4_da_reserve_space(struct inode *inode)
1469 {
1470 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1471 struct ext4_inode_info *ei = EXT4_I(inode);
1472 int ret;
1473
1474 /*
1475 * We will charge metadata quota at writeout time; this saves
1476 * us from metadata over-estimation, though we may go over by
1477 * a small amount in the end. Here we just reserve for data.
1478 */
1479 ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1480 if (ret)
1481 return ret;
1482
1483 spin_lock(&ei->i_block_reservation_lock);
1484 if (ext4_claim_free_clusters(sbi, 1, 0)) {
1485 spin_unlock(&ei->i_block_reservation_lock);
1486 dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1487 return -ENOSPC;
1488 }
1489 ei->i_reserved_data_blocks++;
1490 trace_ext4_da_reserve_space(inode);
1491 spin_unlock(&ei->i_block_reservation_lock);
1492
1493 return 0; /* success */
1494 }
1495
1496 static void ext4_da_release_space(struct inode *inode, int to_free)
1497 {
1498 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1499 struct ext4_inode_info *ei = EXT4_I(inode);
1500
1501 if (!to_free)
1502 return; /* Nothing to release, exit */
1503
1504 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1505
1506 trace_ext4_da_release_space(inode, to_free);
1507 if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1508 /*
1509 * if there aren't enough reserved blocks, then the
1510 * counter is messed up somewhere. Since this
1511 * function is called from invalidate page, it's
1512 * harmless to return without any action.
1513 */
1514 ext4_warning(inode->i_sb, "ext4_da_release_space: "
1515 "ino %lu, to_free %d with only %d reserved "
1516 "data blocks", inode->i_ino, to_free,
1517 ei->i_reserved_data_blocks);
1518 WARN_ON(1);
1519 to_free = ei->i_reserved_data_blocks;
1520 }
1521 ei->i_reserved_data_blocks -= to_free;
1522
1523 /* update fs dirty data blocks counter */
1524 percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1525
1526 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1527
1528 dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1529 }
1530
1531 static void ext4_da_page_release_reservation(struct page *page,
1532 unsigned int offset,
1533 unsigned int length)
1534 {
1535 int to_release = 0, contiguous_blks = 0;
1536 struct buffer_head *head, *bh;
1537 unsigned int curr_off = 0;
1538 struct inode *inode = page->mapping->host;
1539 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1540 unsigned int stop = offset + length;
1541 int num_clusters;
1542 ext4_fsblk_t lblk;
1543
1544 BUG_ON(stop > PAGE_SIZE || stop < length);
1545
1546 head = page_buffers(page);
1547 bh = head;
1548 do {
1549 unsigned int next_off = curr_off + bh->b_size;
1550
1551 if (next_off > stop)
1552 break;
1553
1554 if ((offset <= curr_off) && (buffer_delay(bh))) {
1555 to_release++;
1556 contiguous_blks++;
1557 clear_buffer_delay(bh);
1558 } else if (contiguous_blks) {
1559 lblk = page->index <<
1560 (PAGE_SHIFT - inode->i_blkbits);
1561 lblk += (curr_off >> inode->i_blkbits) -
1562 contiguous_blks;
1563 ext4_es_remove_extent(inode, lblk, contiguous_blks);
1564 contiguous_blks = 0;
1565 }
1566 curr_off = next_off;
1567 } while ((bh = bh->b_this_page) != head);
1568
1569 if (contiguous_blks) {
1570 lblk = page->index << (PAGE_SHIFT - inode->i_blkbits);
1571 lblk += (curr_off >> inode->i_blkbits) - contiguous_blks;
1572 ext4_es_remove_extent(inode, lblk, contiguous_blks);
1573 }
1574
1575 /* If we have released all the blocks belonging to a cluster, then we
1576 * need to release the reserved space for that cluster. */
1577 num_clusters = EXT4_NUM_B2C(sbi, to_release);
1578 while (num_clusters > 0) {
1579 lblk = (page->index << (PAGE_SHIFT - inode->i_blkbits)) +
1580 ((num_clusters - 1) << sbi->s_cluster_bits);
1581 if (sbi->s_cluster_ratio == 1 ||
1582 !ext4_find_delalloc_cluster(inode, lblk))
1583 ext4_da_release_space(inode, 1);
1584
1585 num_clusters--;
1586 }
1587 }
1588
1589 /*
1590 * Delayed allocation stuff
1591 */
1592
1593 struct mpage_da_data {
1594 struct inode *inode;
1595 struct writeback_control *wbc;
1596
1597 pgoff_t first_page; /* The first page to write */
1598 pgoff_t next_page; /* Current page to examine */
1599 pgoff_t last_page; /* Last page to examine */
1600 /*
1601 * Extent to map - this can be after first_page because that can be
1602 * fully mapped. We somewhat abuse m_flags to store whether the extent
1603 * is delalloc or unwritten.
1604 */
1605 struct ext4_map_blocks map;
1606 struct ext4_io_submit io_submit; /* IO submission data */
1607 };
1608
1609 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1610 bool invalidate)
1611 {
1612 int nr_pages, i;
1613 pgoff_t index, end;
1614 struct pagevec pvec;
1615 struct inode *inode = mpd->inode;
1616 struct address_space *mapping = inode->i_mapping;
1617
1618 /* This is necessary when next_page == 0. */
1619 if (mpd->first_page >= mpd->next_page)
1620 return;
1621
1622 index = mpd->first_page;
1623 end = mpd->next_page - 1;
1624 if (invalidate) {
1625 ext4_lblk_t start, last;
1626 start = index << (PAGE_SHIFT - inode->i_blkbits);
1627 last = end << (PAGE_SHIFT - inode->i_blkbits);
1628 ext4_es_remove_extent(inode, start, last - start + 1);
1629 }
1630
1631 pagevec_init(&pvec, 0);
1632 while (index <= end) {
1633 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1634 if (nr_pages == 0)
1635 break;
1636 for (i = 0; i < nr_pages; i++) {
1637 struct page *page = pvec.pages[i];
1638 if (page->index > end)
1639 break;
1640 BUG_ON(!PageLocked(page));
1641 BUG_ON(PageWriteback(page));
1642 if (invalidate) {
1643 block_invalidatepage(page, 0, PAGE_SIZE);
1644 ClearPageUptodate(page);
1645 }
1646 unlock_page(page);
1647 }
1648 index = pvec.pages[nr_pages - 1]->index + 1;
1649 pagevec_release(&pvec);
1650 }
1651 }
1652
1653 static void ext4_print_free_blocks(struct inode *inode)
1654 {
1655 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1656 struct super_block *sb = inode->i_sb;
1657 struct ext4_inode_info *ei = EXT4_I(inode);
1658
1659 ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1660 EXT4_C2B(EXT4_SB(inode->i_sb),
1661 ext4_count_free_clusters(sb)));
1662 ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1663 ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1664 (long long) EXT4_C2B(EXT4_SB(sb),
1665 percpu_counter_sum(&sbi->s_freeclusters_counter)));
1666 ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1667 (long long) EXT4_C2B(EXT4_SB(sb),
1668 percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1669 ext4_msg(sb, KERN_CRIT, "Block reservation details");
1670 ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1671 ei->i_reserved_data_blocks);
1672 return;
1673 }
1674
1675 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
1676 {
1677 return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1678 }
1679
1680 /*
1681 * This function is grabs code from the very beginning of
1682 * ext4_map_blocks, but assumes that the caller is from delayed write
1683 * time. This function looks up the requested blocks and sets the
1684 * buffer delay bit under the protection of i_data_sem.
1685 */
1686 static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1687 struct ext4_map_blocks *map,
1688 struct buffer_head *bh)
1689 {
1690 struct extent_status es;
1691 int retval;
1692 sector_t invalid_block = ~((sector_t) 0xffff);
1693 #ifdef ES_AGGRESSIVE_TEST
1694 struct ext4_map_blocks orig_map;
1695
1696 memcpy(&orig_map, map, sizeof(*map));
1697 #endif
1698
1699 if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1700 invalid_block = ~0;
1701
1702 map->m_flags = 0;
1703 ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u,"
1704 "logical block %lu\n", inode->i_ino, map->m_len,
1705 (unsigned long) map->m_lblk);
1706
1707 /* Lookup extent status tree firstly */
1708 if (ext4_es_lookup_extent(inode, iblock, &es)) {
1709 if (ext4_es_is_hole(&es)) {
1710 retval = 0;
1711 down_read(&EXT4_I(inode)->i_data_sem);
1712 goto add_delayed;
1713 }
1714
1715 /*
1716 * Delayed extent could be allocated by fallocate.
1717 * So we need to check it.
1718 */
1719 if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1720 map_bh(bh, inode->i_sb, invalid_block);
1721 set_buffer_new(bh);
1722 set_buffer_delay(bh);
1723 return 0;
1724 }
1725
1726 map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1727 retval = es.es_len - (iblock - es.es_lblk);
1728 if (retval > map->m_len)
1729 retval = map->m_len;
1730 map->m_len = retval;
1731 if (ext4_es_is_written(&es))
1732 map->m_flags |= EXT4_MAP_MAPPED;
1733 else if (ext4_es_is_unwritten(&es))
1734 map->m_flags |= EXT4_MAP_UNWRITTEN;
1735 else
1736 BUG_ON(1);
1737
1738 #ifdef ES_AGGRESSIVE_TEST
1739 ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1740 #endif
1741 return retval;
1742 }
1743
1744 /*
1745 * Try to see if we can get the block without requesting a new
1746 * file system block.
1747 */
1748 down_read(&EXT4_I(inode)->i_data_sem);
1749 if (ext4_has_inline_data(inode))
1750 retval = 0;
1751 else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1752 retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1753 else
1754 retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1755
1756 add_delayed:
1757 if (retval == 0) {
1758 int ret;
1759 /*
1760 * XXX: __block_prepare_write() unmaps passed block,
1761 * is it OK?
1762 */
1763 /*
1764 * If the block was allocated from previously allocated cluster,
1765 * then we don't need to reserve it again. However we still need
1766 * to reserve metadata for every block we're going to write.
1767 */
1768 if (EXT4_SB(inode->i_sb)->s_cluster_ratio == 1 ||
1769 !ext4_find_delalloc_cluster(inode, map->m_lblk)) {
1770 ret = ext4_da_reserve_space(inode);
1771 if (ret) {
1772 /* not enough space to reserve */
1773 retval = ret;
1774 goto out_unlock;
1775 }
1776 }
1777
1778 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1779 ~0, EXTENT_STATUS_DELAYED);
1780 if (ret) {
1781 retval = ret;
1782 goto out_unlock;
1783 }
1784
1785 map_bh(bh, inode->i_sb, invalid_block);
1786 set_buffer_new(bh);
1787 set_buffer_delay(bh);
1788 } else if (retval > 0) {
1789 int ret;
1790 unsigned int status;
1791
1792 if (unlikely(retval != map->m_len)) {
1793 ext4_warning(inode->i_sb,
1794 "ES len assertion failed for inode "
1795 "%lu: retval %d != map->m_len %d",
1796 inode->i_ino, retval, map->m_len);
1797 WARN_ON(1);
1798 }
1799
1800 status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1801 EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1802 ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1803 map->m_pblk, status);
1804 if (ret != 0)
1805 retval = ret;
1806 }
1807
1808 out_unlock:
1809 up_read((&EXT4_I(inode)->i_data_sem));
1810
1811 return retval;
1812 }
1813
1814 /*
1815 * This is a special get_block_t callback which is used by
1816 * ext4_da_write_begin(). It will either return mapped block or
1817 * reserve space for a single block.
1818 *
1819 * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1820 * We also have b_blocknr = -1 and b_bdev initialized properly
1821 *
1822 * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1823 * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1824 * initialized properly.
1825 */
1826 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1827 struct buffer_head *bh, int create)
1828 {
1829 struct ext4_map_blocks map;
1830 int ret = 0;
1831
1832 BUG_ON(create == 0);
1833 BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1834
1835 map.m_lblk = iblock;
1836 map.m_len = 1;
1837
1838 /*
1839 * first, we need to know whether the block is allocated already
1840 * preallocated blocks are unmapped but should treated
1841 * the same as allocated blocks.
1842 */
1843 ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1844 if (ret <= 0)
1845 return ret;
1846
1847 map_bh(bh, inode->i_sb, map.m_pblk);
1848 ext4_update_bh_state(bh, map.m_flags);
1849
1850 if (buffer_unwritten(bh)) {
1851 /* A delayed write to unwritten bh should be marked
1852 * new and mapped. Mapped ensures that we don't do
1853 * get_block multiple times when we write to the same
1854 * offset and new ensures that we do proper zero out
1855 * for partial write.
1856 */
1857 set_buffer_new(bh);
1858 set_buffer_mapped(bh);
1859 }
1860 return 0;
1861 }
1862
1863 static int bget_one(handle_t *handle, struct buffer_head *bh)
1864 {
1865 get_bh(bh);
1866 return 0;
1867 }
1868
1869 static int bput_one(handle_t *handle, struct buffer_head *bh)
1870 {
1871 put_bh(bh);
1872 return 0;
1873 }
1874
1875 static int __ext4_journalled_writepage(struct page *page,
1876 unsigned int len)
1877 {
1878 struct address_space *mapping = page->mapping;
1879 struct inode *inode = mapping->host;
1880 struct buffer_head *page_bufs = NULL;
1881 handle_t *handle = NULL;
1882 int ret = 0, err = 0;
1883 int inline_data = ext4_has_inline_data(inode);
1884 struct buffer_head *inode_bh = NULL;
1885
1886 ClearPageChecked(page);
1887
1888 if (inline_data) {
1889 BUG_ON(page->index != 0);
1890 BUG_ON(len > ext4_get_max_inline_size(inode));
1891 inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1892 if (inode_bh == NULL)
1893 goto out;
1894 } else {
1895 page_bufs = page_buffers(page);
1896 if (!page_bufs) {
1897 BUG();
1898 goto out;
1899 }
1900 ext4_walk_page_buffers(handle, page_bufs, 0, len,
1901 NULL, bget_one);
1902 }
1903 /*
1904 * We need to release the page lock before we start the
1905 * journal, so grab a reference so the page won't disappear
1906 * out from under us.
1907 */
1908 get_page(page);
1909 unlock_page(page);
1910
1911 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1912 ext4_writepage_trans_blocks(inode));
1913 if (IS_ERR(handle)) {
1914 ret = PTR_ERR(handle);
1915 put_page(page);
1916 goto out_no_pagelock;
1917 }
1918 BUG_ON(!ext4_handle_valid(handle));
1919
1920 lock_page(page);
1921 put_page(page);
1922 if (page->mapping != mapping) {
1923 /* The page got truncated from under us */
1924 ext4_journal_stop(handle);
1925 ret = 0;
1926 goto out;
1927 }
1928
1929 if (inline_data) {
1930 BUFFER_TRACE(inode_bh, "get write access");
1931 ret = ext4_journal_get_write_access(handle, inode_bh);
1932
1933 err = ext4_handle_dirty_metadata(handle, inode, inode_bh);
1934
1935 } else {
1936 ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1937 do_journal_get_write_access);
1938
1939 err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL,
1940 write_end_fn);
1941 }
1942 if (ret == 0)
1943 ret = err;
1944 EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1945 err = ext4_journal_stop(handle);
1946 if (!ret)
1947 ret = err;
1948
1949 if (!ext4_has_inline_data(inode))
1950 ext4_walk_page_buffers(NULL, page_bufs, 0, len,
1951 NULL, bput_one);
1952 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1953 out:
1954 unlock_page(page);
1955 out_no_pagelock:
1956 brelse(inode_bh);
1957 return ret;
1958 }
1959
1960 /*
1961 * Note that we don't need to start a transaction unless we're journaling data
1962 * because we should have holes filled from ext4_page_mkwrite(). We even don't
1963 * need to file the inode to the transaction's list in ordered mode because if
1964 * we are writing back data added by write(), the inode is already there and if
1965 * we are writing back data modified via mmap(), no one guarantees in which
1966 * transaction the data will hit the disk. In case we are journaling data, we
1967 * cannot start transaction directly because transaction start ranks above page
1968 * lock so we have to do some magic.
1969 *
1970 * This function can get called via...
1971 * - ext4_writepages after taking page lock (have journal handle)
1972 * - journal_submit_inode_data_buffers (no journal handle)
1973 * - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1974 * - grab_page_cache when doing write_begin (have journal handle)
1975 *
1976 * We don't do any block allocation in this function. If we have page with
1977 * multiple blocks we need to write those buffer_heads that are mapped. This
1978 * is important for mmaped based write. So if we do with blocksize 1K
1979 * truncate(f, 1024);
1980 * a = mmap(f, 0, 4096);
1981 * a[0] = 'a';
1982 * truncate(f, 4096);
1983 * we have in the page first buffer_head mapped via page_mkwrite call back
1984 * but other buffer_heads would be unmapped but dirty (dirty done via the
1985 * do_wp_page). So writepage should write the first block. If we modify
1986 * the mmap area beyond 1024 we will again get a page_fault and the
1987 * page_mkwrite callback will do the block allocation and mark the
1988 * buffer_heads mapped.
1989 *
1990 * We redirty the page if we have any buffer_heads that is either delay or
1991 * unwritten in the page.
1992 *
1993 * We can get recursively called as show below.
1994 *
1995 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1996 * ext4_writepage()
1997 *
1998 * But since we don't do any block allocation we should not deadlock.
1999 * Page also have the dirty flag cleared so we don't get recurive page_lock.
2000 */
2001 static int ext4_writepage(struct page *page,
2002 struct writeback_control *wbc)
2003 {
2004 int ret = 0;
2005 loff_t size;
2006 unsigned int len;
2007 struct buffer_head *page_bufs = NULL;
2008 struct inode *inode = page->mapping->host;
2009 struct ext4_io_submit io_submit;
2010 bool keep_towrite = false;
2011
2012 trace_ext4_writepage(page);
2013 size = i_size_read(inode);
2014 if (page->index == size >> PAGE_SHIFT)
2015 len = size & ~PAGE_MASK;
2016 else
2017 len = PAGE_SIZE;
2018
2019 page_bufs = page_buffers(page);
2020 /*
2021 * We cannot do block allocation or other extent handling in this
2022 * function. If there are buffers needing that, we have to redirty
2023 * the page. But we may reach here when we do a journal commit via
2024 * journal_submit_inode_data_buffers() and in that case we must write
2025 * allocated buffers to achieve data=ordered mode guarantees.
2026 *
2027 * Also, if there is only one buffer per page (the fs block
2028 * size == the page size), if one buffer needs block
2029 * allocation or needs to modify the extent tree to clear the
2030 * unwritten flag, we know that the page can't be written at
2031 * all, so we might as well refuse the write immediately.
2032 * Unfortunately if the block size != page size, we can't as
2033 * easily detect this case using ext4_walk_page_buffers(), but
2034 * for the extremely common case, this is an optimization that
2035 * skips a useless round trip through ext4_bio_write_page().
2036 */
2037 if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2038 ext4_bh_delay_or_unwritten)) {
2039 redirty_page_for_writepage(wbc, page);
2040 if ((current->flags & PF_MEMALLOC) ||
2041 (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2042 /*
2043 * For memory cleaning there's no point in writing only
2044 * some buffers. So just bail out. Warn if we came here
2045 * from direct reclaim.
2046 */
2047 WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2048 == PF_MEMALLOC);
2049 unlock_page(page);
2050 return 0;
2051 }
2052 keep_towrite = true;
2053 }
2054
2055 if (PageChecked(page) && ext4_should_journal_data(inode))
2056 /*
2057 * It's mmapped pagecache. Add buffers and journal it. There
2058 * doesn't seem much point in redirtying the page here.
2059 */
2060 return __ext4_journalled_writepage(page, len);
2061
2062 ext4_io_submit_init(&io_submit, wbc);
2063 io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2064 if (!io_submit.io_end) {
2065 redirty_page_for_writepage(wbc, page);
2066 unlock_page(page);
2067 return -ENOMEM;
2068 }
2069 ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite);
2070 ext4_io_submit(&io_submit);
2071 /* Drop io_end reference we got from init */
2072 ext4_put_io_end_defer(io_submit.io_end);
2073 return ret;
2074 }
2075
2076 static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2077 {
2078 int len;
2079 loff_t size = i_size_read(mpd->inode);
2080 int err;
2081
2082 BUG_ON(page->index != mpd->first_page);
2083 if (page->index == size >> PAGE_SHIFT)
2084 len = size & ~PAGE_MASK;
2085 else
2086 len = PAGE_SIZE;
2087 clear_page_dirty_for_io(page);
2088 err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false);
2089 if (!err)
2090 mpd->wbc->nr_to_write--;
2091 mpd->first_page++;
2092
2093 return err;
2094 }
2095
2096 #define BH_FLAGS ((1 << BH_Unwritten) | (1 << BH_Delay))
2097
2098 /*
2099 * mballoc gives us at most this number of blocks...
2100 * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2101 * The rest of mballoc seems to handle chunks up to full group size.
2102 */
2103 #define MAX_WRITEPAGES_EXTENT_LEN 2048
2104
2105 /*
2106 * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2107 *
2108 * @mpd - extent of blocks
2109 * @lblk - logical number of the block in the file
2110 * @bh - buffer head we want to add to the extent
2111 *
2112 * The function is used to collect contig. blocks in the same state. If the
2113 * buffer doesn't require mapping for writeback and we haven't started the
2114 * extent of buffers to map yet, the function returns 'true' immediately - the
2115 * caller can write the buffer right away. Otherwise the function returns true
2116 * if the block has been added to the extent, false if the block couldn't be
2117 * added.
2118 */
2119 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2120 struct buffer_head *bh)
2121 {
2122 struct ext4_map_blocks *map = &mpd->map;
2123
2124 /* Buffer that doesn't need mapping for writeback? */
2125 if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2126 (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2127 /* So far no extent to map => we write the buffer right away */
2128 if (map->m_len == 0)
2129 return true;
2130 return false;
2131 }
2132
2133 /* First block in the extent? */
2134 if (map->m_len == 0) {
2135 map->m_lblk = lblk;
2136 map->m_len = 1;
2137 map->m_flags = bh->b_state & BH_FLAGS;
2138 return true;
2139 }
2140
2141 /* Don't go larger than mballoc is willing to allocate */
2142 if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2143 return false;
2144
2145 /* Can we merge the block to our big extent? */
2146 if (lblk == map->m_lblk + map->m_len &&
2147 (bh->b_state & BH_FLAGS) == map->m_flags) {
2148 map->m_len++;
2149 return true;
2150 }
2151 return false;
2152 }
2153
2154 /*
2155 * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2156 *
2157 * @mpd - extent of blocks for mapping
2158 * @head - the first buffer in the page
2159 * @bh - buffer we should start processing from
2160 * @lblk - logical number of the block in the file corresponding to @bh
2161 *
2162 * Walk through page buffers from @bh upto @head (exclusive) and either submit
2163 * the page for IO if all buffers in this page were mapped and there's no
2164 * accumulated extent of buffers to map or add buffers in the page to the
2165 * extent of buffers to map. The function returns 1 if the caller can continue
2166 * by processing the next page, 0 if it should stop adding buffers to the
2167 * extent to map because we cannot extend it anymore. It can also return value
2168 * < 0 in case of error during IO submission.
2169 */
2170 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2171 struct buffer_head *head,
2172 struct buffer_head *bh,
2173 ext4_lblk_t lblk)
2174 {
2175 struct inode *inode = mpd->inode;
2176 int err;
2177 ext4_lblk_t blocks = (i_size_read(inode) + (1 << inode->i_blkbits) - 1)
2178 >> inode->i_blkbits;
2179
2180 do {
2181 BUG_ON(buffer_locked(bh));
2182
2183 if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2184 /* Found extent to map? */
2185 if (mpd->map.m_len)
2186 return 0;
2187 /* Everything mapped so far and we hit EOF */
2188 break;
2189 }
2190 } while (lblk++, (bh = bh->b_this_page) != head);
2191 /* So far everything mapped? Submit the page for IO. */
2192 if (mpd->map.m_len == 0) {
2193 err = mpage_submit_page(mpd, head->b_page);
2194 if (err < 0)
2195 return err;
2196 }
2197 return lblk < blocks;
2198 }
2199
2200 /*
2201 * mpage_map_buffers - update buffers corresponding to changed extent and
2202 * submit fully mapped pages for IO
2203 *
2204 * @mpd - description of extent to map, on return next extent to map
2205 *
2206 * Scan buffers corresponding to changed extent (we expect corresponding pages
2207 * to be already locked) and update buffer state according to new extent state.
2208 * We map delalloc buffers to their physical location, clear unwritten bits,
2209 * and mark buffers as uninit when we perform writes to unwritten extents
2210 * and do extent conversion after IO is finished. If the last page is not fully
2211 * mapped, we update @map to the next extent in the last page that needs
2212 * mapping. Otherwise we submit the page for IO.
2213 */
2214 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2215 {
2216 struct pagevec pvec;
2217 int nr_pages, i;
2218 struct inode *inode = mpd->inode;
2219 struct buffer_head *head, *bh;
2220 int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2221 pgoff_t start, end;
2222 ext4_lblk_t lblk;
2223 sector_t pblock;
2224 int err;
2225
2226 start = mpd->map.m_lblk >> bpp_bits;
2227 end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2228 lblk = start << bpp_bits;
2229 pblock = mpd->map.m_pblk;
2230
2231 pagevec_init(&pvec, 0);
2232 while (start <= end) {
2233 nr_pages = pagevec_lookup(&pvec, inode->i_mapping, start,
2234 PAGEVEC_SIZE);
2235 if (nr_pages == 0)
2236 break;
2237 for (i = 0; i < nr_pages; i++) {
2238 struct page *page = pvec.pages[i];
2239
2240 if (page->index > end)
2241 break;
2242 /* Up to 'end' pages must be contiguous */
2243 BUG_ON(page->index != start);
2244 bh = head = page_buffers(page);
2245 do {
2246 if (lblk < mpd->map.m_lblk)
2247 continue;
2248 if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2249 /*
2250 * Buffer after end of mapped extent.
2251 * Find next buffer in the page to map.
2252 */
2253 mpd->map.m_len = 0;
2254 mpd->map.m_flags = 0;
2255 /*
2256 * FIXME: If dioread_nolock supports
2257 * blocksize < pagesize, we need to make
2258 * sure we add size mapped so far to
2259 * io_end->size as the following call
2260 * can submit the page for IO.
2261 */
2262 err = mpage_process_page_bufs(mpd, head,
2263 bh, lblk);
2264 pagevec_release(&pvec);
2265 if (err > 0)
2266 err = 0;
2267 return err;
2268 }
2269 if (buffer_delay(bh)) {
2270 clear_buffer_delay(bh);
2271 bh->b_blocknr = pblock++;
2272 }
2273 clear_buffer_unwritten(bh);
2274 } while (lblk++, (bh = bh->b_this_page) != head);
2275
2276 /*
2277 * FIXME: This is going to break if dioread_nolock
2278 * supports blocksize < pagesize as we will try to
2279 * convert potentially unmapped parts of inode.
2280 */
2281 mpd->io_submit.io_end->size += PAGE_SIZE;
2282 /* Page fully mapped - let IO run! */
2283 err = mpage_submit_page(mpd, page);
2284 if (err < 0) {
2285 pagevec_release(&pvec);
2286 return err;
2287 }
2288 start++;
2289 }
2290 pagevec_release(&pvec);
2291 }
2292 /* Extent fully mapped and matches with page boundary. We are done. */
2293 mpd->map.m_len = 0;
2294 mpd->map.m_flags = 0;
2295 return 0;
2296 }
2297
2298 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2299 {
2300 struct inode *inode = mpd->inode;
2301 struct ext4_map_blocks *map = &mpd->map;
2302 int get_blocks_flags;
2303 int err, dioread_nolock;
2304
2305 trace_ext4_da_write_pages_extent(inode, map);
2306 /*
2307 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2308 * to convert an unwritten extent to be initialized (in the case
2309 * where we have written into one or more preallocated blocks). It is
2310 * possible that we're going to need more metadata blocks than
2311 * previously reserved. However we must not fail because we're in
2312 * writeback and there is nothing we can do about it so it might result
2313 * in data loss. So use reserved blocks to allocate metadata if
2314 * possible.
2315 *
2316 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2317 * the blocks in question are delalloc blocks. This indicates
2318 * that the blocks and quotas has already been checked when
2319 * the data was copied into the page cache.
2320 */
2321 get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2322 EXT4_GET_BLOCKS_METADATA_NOFAIL;
2323 dioread_nolock = ext4_should_dioread_nolock(inode);
2324 if (dioread_nolock)
2325 get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2326 if (map->m_flags & (1 << BH_Delay))
2327 get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2328
2329 err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2330 if (err < 0)
2331 return err;
2332 if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2333 if (!mpd->io_submit.io_end->handle &&
2334 ext4_handle_valid(handle)) {
2335 mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2336 handle->h_rsv_handle = NULL;
2337 }
2338 ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2339 }
2340
2341 BUG_ON(map->m_len == 0);
2342 if (map->m_flags & EXT4_MAP_NEW) {
2343 struct block_device *bdev = inode->i_sb->s_bdev;
2344 int i;
2345
2346 for (i = 0; i < map->m_len; i++)
2347 unmap_underlying_metadata(bdev, map->m_pblk + i);
2348 }
2349 return 0;
2350 }
2351
2352 /*
2353 * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2354 * mpd->len and submit pages underlying it for IO
2355 *
2356 * @handle - handle for journal operations
2357 * @mpd - extent to map
2358 * @give_up_on_write - we set this to true iff there is a fatal error and there
2359 * is no hope of writing the data. The caller should discard
2360 * dirty pages to avoid infinite loops.
2361 *
2362 * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2363 * delayed, blocks are allocated, if it is unwritten, we may need to convert
2364 * them to initialized or split the described range from larger unwritten
2365 * extent. Note that we need not map all the described range since allocation
2366 * can return less blocks or the range is covered by more unwritten extents. We
2367 * cannot map more because we are limited by reserved transaction credits. On
2368 * the other hand we always make sure that the last touched page is fully
2369 * mapped so that it can be written out (and thus forward progress is
2370 * guaranteed). After mapping we submit all mapped pages for IO.
2371 */
2372 static int mpage_map_and_submit_extent(handle_t *handle,
2373 struct mpage_da_data *mpd,
2374 bool *give_up_on_write)
2375 {
2376 struct inode *inode = mpd->inode;
2377 struct ext4_map_blocks *map = &mpd->map;
2378 int err;
2379 loff_t disksize;
2380 int progress = 0;
2381
2382 mpd->io_submit.io_end->offset =
2383 ((loff_t)map->m_lblk) << inode->i_blkbits;
2384 do {
2385 err = mpage_map_one_extent(handle, mpd);
2386 if (err < 0) {
2387 struct super_block *sb = inode->i_sb;
2388
2389 if (EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)
2390 goto invalidate_dirty_pages;
2391 /*
2392 * Let the uper layers retry transient errors.
2393 * In the case of ENOSPC, if ext4_count_free_blocks()
2394 * is non-zero, a commit should free up blocks.
2395 */
2396 if ((err == -ENOMEM) ||
2397 (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2398 if (progress)
2399 goto update_disksize;
2400 return err;
2401 }
2402 ext4_msg(sb, KERN_CRIT,
2403 "Delayed block allocation failed for "
2404 "inode %lu at logical offset %llu with"
2405 " max blocks %u with error %d",
2406 inode->i_ino,
2407 (unsigned long long)map->m_lblk,
2408 (unsigned)map->m_len, -err);
2409 ext4_msg(sb, KERN_CRIT,
2410 "This should not happen!! Data will "
2411 "be lost\n");
2412 if (err == -ENOSPC)
2413 ext4_print_free_blocks(inode);
2414 invalidate_dirty_pages:
2415 *give_up_on_write = true;
2416 return err;
2417 }
2418 progress = 1;
2419 /*
2420 * Update buffer state, submit mapped pages, and get us new
2421 * extent to map
2422 */
2423 err = mpage_map_and_submit_buffers(mpd);
2424 if (err < 0)
2425 goto update_disksize;
2426 } while (map->m_len);
2427
2428 update_disksize:
2429 /*
2430 * Update on-disk size after IO is submitted. Races with
2431 * truncate are avoided by checking i_size under i_data_sem.
2432 */
2433 disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2434 if (disksize > EXT4_I(inode)->i_disksize) {
2435 int err2;
2436 loff_t i_size;
2437
2438 down_write(&EXT4_I(inode)->i_data_sem);
2439 i_size = i_size_read(inode);
2440 if (disksize > i_size)
2441 disksize = i_size;
2442 if (disksize > EXT4_I(inode)->i_disksize)
2443 EXT4_I(inode)->i_disksize = disksize;
2444 err2 = ext4_mark_inode_dirty(handle, inode);
2445 up_write(&EXT4_I(inode)->i_data_sem);
2446 if (err2)
2447 ext4_error(inode->i_sb,
2448 "Failed to mark inode %lu dirty",
2449 inode->i_ino);
2450 if (!err)
2451 err = err2;
2452 }
2453 return err;
2454 }
2455
2456 /*
2457 * Calculate the total number of credits to reserve for one writepages
2458 * iteration. This is called from ext4_writepages(). We map an extent of
2459 * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2460 * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2461 * bpp - 1 blocks in bpp different extents.
2462 */
2463 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2464 {
2465 int bpp = ext4_journal_blocks_per_page(inode);
2466
2467 return ext4_meta_trans_blocks(inode,
2468 MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2469 }
2470
2471 /*
2472 * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2473 * and underlying extent to map
2474 *
2475 * @mpd - where to look for pages
2476 *
2477 * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2478 * IO immediately. When we find a page which isn't mapped we start accumulating
2479 * extent of buffers underlying these pages that needs mapping (formed by
2480 * either delayed or unwritten buffers). We also lock the pages containing
2481 * these buffers. The extent found is returned in @mpd structure (starting at
2482 * mpd->lblk with length mpd->len blocks).
2483 *
2484 * Note that this function can attach bios to one io_end structure which are
2485 * neither logically nor physically contiguous. Although it may seem as an
2486 * unnecessary complication, it is actually inevitable in blocksize < pagesize
2487 * case as we need to track IO to all buffers underlying a page in one io_end.
2488 */
2489 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2490 {
2491 struct address_space *mapping = mpd->inode->i_mapping;
2492 struct pagevec pvec;
2493 unsigned int nr_pages;
2494 long left = mpd->wbc->nr_to_write;
2495 pgoff_t index = mpd->first_page;
2496 pgoff_t end = mpd->last_page;
2497 int tag;
2498 int i, err = 0;
2499 int blkbits = mpd->inode->i_blkbits;
2500 ext4_lblk_t lblk;
2501 struct buffer_head *head;
2502
2503 if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2504 tag = PAGECACHE_TAG_TOWRITE;
2505 else
2506 tag = PAGECACHE_TAG_DIRTY;
2507
2508 pagevec_init(&pvec, 0);
2509 mpd->map.m_len = 0;
2510 mpd->next_page = index;
2511 while (index <= end) {
2512 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
2513 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
2514 if (nr_pages == 0)
2515 goto out;
2516
2517 for (i = 0; i < nr_pages; i++) {
2518 struct page *page = pvec.pages[i];
2519
2520 /*
2521 * At this point, the page may be truncated or
2522 * invalidated (changing page->mapping to NULL), or
2523 * even swizzled back from swapper_space to tmpfs file
2524 * mapping. However, page->index will not change
2525 * because we have a reference on the page.
2526 */
2527 if (page->index > end)
2528 goto out;
2529
2530 /*
2531 * Accumulated enough dirty pages? This doesn't apply
2532 * to WB_SYNC_ALL mode. For integrity sync we have to
2533 * keep going because someone may be concurrently
2534 * dirtying pages, and we might have synced a lot of
2535 * newly appeared dirty pages, but have not synced all
2536 * of the old dirty pages.
2537 */
2538 if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2539 goto out;
2540
2541 /* If we can't merge this page, we are done. */
2542 if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2543 goto out;
2544
2545 lock_page(page);
2546 /*
2547 * If the page is no longer dirty, or its mapping no
2548 * longer corresponds to inode we are writing (which
2549 * means it has been truncated or invalidated), or the
2550 * page is already under writeback and we are not doing
2551 * a data integrity writeback, skip the page
2552 */
2553 if (!PageDirty(page) ||
2554 (PageWriteback(page) &&
2555 (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2556 unlikely(page->mapping != mapping)) {
2557 unlock_page(page);
2558 continue;
2559 }
2560
2561 wait_on_page_writeback(page);
2562 BUG_ON(PageWriteback(page));
2563
2564 if (mpd->map.m_len == 0)
2565 mpd->first_page = page->index;
2566 mpd->next_page = page->index + 1;
2567 /* Add all dirty buffers to mpd */
2568 lblk = ((ext4_lblk_t)page->index) <<
2569 (PAGE_SHIFT - blkbits);
2570 head = page_buffers(page);
2571 err = mpage_process_page_bufs(mpd, head, head, lblk);
2572 if (err <= 0)
2573 goto out;
2574 err = 0;
2575 left--;
2576 }
2577 pagevec_release(&pvec);
2578 cond_resched();
2579 }
2580 return 0;
2581 out:
2582 pagevec_release(&pvec);
2583 return err;
2584 }
2585
2586 static int __writepage(struct page *page, struct writeback_control *wbc,
2587 void *data)
2588 {
2589 struct address_space *mapping = data;
2590 int ret = ext4_writepage(page, wbc);
2591 mapping_set_error(mapping, ret);
2592 return ret;
2593 }
2594
2595 static int ext4_writepages(struct address_space *mapping,
2596 struct writeback_control *wbc)
2597 {
2598 pgoff_t writeback_index = 0;
2599 long nr_to_write = wbc->nr_to_write;
2600 int range_whole = 0;
2601 int cycled = 1;
2602 handle_t *handle = NULL;
2603 struct mpage_da_data mpd;
2604 struct inode *inode = mapping->host;
2605 int needed_blocks, rsv_blocks = 0, ret = 0;
2606 struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2607 bool done;
2608 struct blk_plug plug;
2609 bool give_up_on_write = false;
2610
2611 trace_ext4_writepages(inode, wbc);
2612
2613 if (dax_mapping(mapping))
2614 return dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev,
2615 wbc);
2616
2617 /*
2618 * No pages to write? This is mainly a kludge to avoid starting
2619 * a transaction for special inodes like journal inode on last iput()
2620 * because that could violate lock ordering on umount
2621 */
2622 if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2623 goto out_writepages;
2624
2625 if (ext4_should_journal_data(inode)) {
2626 struct blk_plug plug;
2627
2628 blk_start_plug(&plug);
2629 ret = write_cache_pages(mapping, wbc, __writepage, mapping);
2630 blk_finish_plug(&plug);
2631 goto out_writepages;
2632 }
2633
2634 /*
2635 * If the filesystem has aborted, it is read-only, so return
2636 * right away instead of dumping stack traces later on that
2637 * will obscure the real source of the problem. We test
2638 * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2639 * the latter could be true if the filesystem is mounted
2640 * read-only, and in that case, ext4_writepages should
2641 * *never* be called, so if that ever happens, we would want
2642 * the stack trace.
2643 */
2644 if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
2645 ret = -EROFS;
2646 goto out_writepages;
2647 }
2648
2649 if (ext4_should_dioread_nolock(inode)) {
2650 /*
2651 * We may need to convert up to one extent per block in
2652 * the page and we may dirty the inode.
2653 */
2654 rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
2655 }
2656
2657 /*
2658 * If we have inline data and arrive here, it means that
2659 * we will soon create the block for the 1st page, so
2660 * we'd better clear the inline data here.
2661 */
2662 if (ext4_has_inline_data(inode)) {
2663 /* Just inode will be modified... */
2664 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2665 if (IS_ERR(handle)) {
2666 ret = PTR_ERR(handle);
2667 goto out_writepages;
2668 }
2669 BUG_ON(ext4_test_inode_state(inode,
2670 EXT4_STATE_MAY_INLINE_DATA));
2671 ext4_destroy_inline_data(handle, inode);
2672 ext4_journal_stop(handle);
2673 }
2674
2675 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2676 range_whole = 1;
2677
2678 if (wbc->range_cyclic) {
2679 writeback_index = mapping->writeback_index;
2680 if (writeback_index)
2681 cycled = 0;
2682 mpd.first_page = writeback_index;
2683 mpd.last_page = -1;
2684 } else {
2685 mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2686 mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2687 }
2688
2689 mpd.inode = inode;
2690 mpd.wbc = wbc;
2691 ext4_io_submit_init(&mpd.io_submit, wbc);
2692 retry:
2693 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2694 tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2695 done = false;
2696 blk_start_plug(&plug);
2697 while (!done && mpd.first_page <= mpd.last_page) {
2698 /* For each extent of pages we use new io_end */
2699 mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2700 if (!mpd.io_submit.io_end) {
2701 ret = -ENOMEM;
2702 break;
2703 }
2704
2705 /*
2706 * We have two constraints: We find one extent to map and we
2707 * must always write out whole page (makes a difference when
2708 * blocksize < pagesize) so that we don't block on IO when we
2709 * try to write out the rest of the page. Journalled mode is
2710 * not supported by delalloc.
2711 */
2712 BUG_ON(ext4_should_journal_data(inode));
2713 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2714
2715 /* start a new transaction */
2716 handle = ext4_journal_start_with_reserve(inode,
2717 EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2718 if (IS_ERR(handle)) {
2719 ret = PTR_ERR(handle);
2720 ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2721 "%ld pages, ino %lu; err %d", __func__,
2722 wbc->nr_to_write, inode->i_ino, ret);
2723 /* Release allocated io_end */
2724 ext4_put_io_end(mpd.io_submit.io_end);
2725 break;
2726 }
2727
2728 trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2729 ret = mpage_prepare_extent_to_map(&mpd);
2730 if (!ret) {
2731 if (mpd.map.m_len)
2732 ret = mpage_map_and_submit_extent(handle, &mpd,
2733 &give_up_on_write);
2734 else {
2735 /*
2736 * We scanned the whole range (or exhausted
2737 * nr_to_write), submitted what was mapped and
2738 * didn't find anything needing mapping. We are
2739 * done.
2740 */
2741 done = true;
2742 }
2743 }
2744 /*
2745 * Caution: If the handle is synchronous,
2746 * ext4_journal_stop() can wait for transaction commit
2747 * to finish which may depend on writeback of pages to
2748 * complete or on page lock to be released. In that
2749 * case, we have to wait until after after we have
2750 * submitted all the IO, released page locks we hold,
2751 * and dropped io_end reference (for extent conversion
2752 * to be able to complete) before stopping the handle.
2753 */
2754 if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2755 ext4_journal_stop(handle);
2756 handle = NULL;
2757 }
2758 /* Submit prepared bio */
2759 ext4_io_submit(&mpd.io_submit);
2760 /* Unlock pages we didn't use */
2761 mpage_release_unused_pages(&mpd, give_up_on_write);
2762 /*
2763 * Drop our io_end reference we got from init. We have
2764 * to be careful and use deferred io_end finishing if
2765 * we are still holding the transaction as we can
2766 * release the last reference to io_end which may end
2767 * up doing unwritten extent conversion.
2768 */
2769 if (handle) {
2770 ext4_put_io_end_defer(mpd.io_submit.io_end);
2771 ext4_journal_stop(handle);
2772 } else
2773 ext4_put_io_end(mpd.io_submit.io_end);
2774
2775 if (ret == -ENOSPC && sbi->s_journal) {
2776 /*
2777 * Commit the transaction which would
2778 * free blocks released in the transaction
2779 * and try again
2780 */
2781 jbd2_journal_force_commit_nested(sbi->s_journal);
2782 ret = 0;
2783 continue;
2784 }
2785 /* Fatal error - ENOMEM, EIO... */
2786 if (ret)
2787 break;
2788 }
2789 blk_finish_plug(&plug);
2790 if (!ret && !cycled && wbc->nr_to_write > 0) {
2791 cycled = 1;
2792 mpd.last_page = writeback_index - 1;
2793 mpd.first_page = 0;
2794 goto retry;
2795 }
2796
2797 /* Update index */
2798 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2799 /*
2800 * Set the writeback_index so that range_cyclic
2801 * mode will write it back later
2802 */
2803 mapping->writeback_index = mpd.first_page;
2804
2805 out_writepages:
2806 trace_ext4_writepages_result(inode, wbc, ret,
2807 nr_to_write - wbc->nr_to_write);
2808 return ret;
2809 }
2810
2811 static int ext4_nonda_switch(struct super_block *sb)
2812 {
2813 s64 free_clusters, dirty_clusters;
2814 struct ext4_sb_info *sbi = EXT4_SB(sb);
2815
2816 /*
2817 * switch to non delalloc mode if we are running low
2818 * on free block. The free block accounting via percpu
2819 * counters can get slightly wrong with percpu_counter_batch getting
2820 * accumulated on each CPU without updating global counters
2821 * Delalloc need an accurate free block accounting. So switch
2822 * to non delalloc when we are near to error range.
2823 */
2824 free_clusters =
2825 percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2826 dirty_clusters =
2827 percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2828 /*
2829 * Start pushing delalloc when 1/2 of free blocks are dirty.
2830 */
2831 if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2832 try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2833
2834 if (2 * free_clusters < 3 * dirty_clusters ||
2835 free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2836 /*
2837 * free block count is less than 150% of dirty blocks
2838 * or free blocks is less than watermark
2839 */
2840 return 1;
2841 }
2842 return 0;
2843 }
2844
2845 /* We always reserve for an inode update; the superblock could be there too */
2846 static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len)
2847 {
2848 if (likely(ext4_has_feature_large_file(inode->i_sb)))
2849 return 1;
2850
2851 if (pos + len <= 0x7fffffffULL)
2852 return 1;
2853
2854 /* We might need to update the superblock to set LARGE_FILE */
2855 return 2;
2856 }
2857
2858 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2859 loff_t pos, unsigned len, unsigned flags,
2860 struct page **pagep, void **fsdata)
2861 {
2862 int ret, retries = 0;
2863 struct page *page;
2864 pgoff_t index;
2865 struct inode *inode = mapping->host;
2866 handle_t *handle;
2867
2868 index = pos >> PAGE_SHIFT;
2869
2870 if (ext4_nonda_switch(inode->i_sb)) {
2871 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2872 return ext4_write_begin(file, mapping, pos,
2873 len, flags, pagep, fsdata);
2874 }
2875 *fsdata = (void *)0;
2876 trace_ext4_da_write_begin(inode, pos, len, flags);
2877
2878 if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2879 ret = ext4_da_write_inline_data_begin(mapping, inode,
2880 pos, len, flags,
2881 pagep, fsdata);
2882 if (ret < 0)
2883 return ret;
2884 if (ret == 1)
2885 return 0;
2886 }
2887
2888 /*
2889 * grab_cache_page_write_begin() can take a long time if the
2890 * system is thrashing due to memory pressure, or if the page
2891 * is being written back. So grab it first before we start
2892 * the transaction handle. This also allows us to allocate
2893 * the page (if needed) without using GFP_NOFS.
2894 */
2895 retry_grab:
2896 page = grab_cache_page_write_begin(mapping, index, flags);
2897 if (!page)
2898 return -ENOMEM;
2899 unlock_page(page);
2900
2901 /*
2902 * With delayed allocation, we don't log the i_disksize update
2903 * if there is delayed block allocation. But we still need
2904 * to journalling the i_disksize update if writes to the end
2905 * of file which has an already mapped buffer.
2906 */
2907 retry_journal:
2908 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
2909 ext4_da_write_credits(inode, pos, len));
2910 if (IS_ERR(handle)) {
2911 put_page(page);
2912 return PTR_ERR(handle);
2913 }
2914
2915 lock_page(page);
2916 if (page->mapping != mapping) {
2917 /* The page got truncated from under us */
2918 unlock_page(page);
2919 put_page(page);
2920 ext4_journal_stop(handle);
2921 goto retry_grab;
2922 }
2923 /* In case writeback began while the page was unlocked */
2924 wait_for_stable_page(page);
2925
2926 #ifdef CONFIG_EXT4_FS_ENCRYPTION
2927 ret = ext4_block_write_begin(page, pos, len,
2928 ext4_da_get_block_prep);
2929 #else
2930 ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
2931 #endif
2932 if (ret < 0) {
2933 unlock_page(page);
2934 ext4_journal_stop(handle);
2935 /*
2936 * block_write_begin may have instantiated a few blocks
2937 * outside i_size. Trim these off again. Don't need
2938 * i_size_read because we hold i_mutex.
2939 */
2940 if (pos + len > inode->i_size)
2941 ext4_truncate_failed_write(inode);
2942
2943 if (ret == -ENOSPC &&
2944 ext4_should_retry_alloc(inode->i_sb, &retries))
2945 goto retry_journal;
2946
2947 put_page(page);
2948 return ret;
2949 }
2950
2951 *pagep = page;
2952 return ret;
2953 }
2954
2955 /*
2956 * Check if we should update i_disksize
2957 * when write to the end of file but not require block allocation
2958 */
2959 static int ext4_da_should_update_i_disksize(struct page *page,
2960 unsigned long offset)
2961 {
2962 struct buffer_head *bh;
2963 struct inode *inode = page->mapping->host;
2964 unsigned int idx;
2965 int i;
2966
2967 bh = page_buffers(page);
2968 idx = offset >> inode->i_blkbits;
2969
2970 for (i = 0; i < idx; i++)
2971 bh = bh->b_this_page;
2972
2973 if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2974 return 0;
2975 return 1;
2976 }
2977
2978 static int ext4_da_write_end(struct file *file,
2979 struct address_space *mapping,
2980 loff_t pos, unsigned len, unsigned copied,
2981 struct page *page, void *fsdata)
2982 {
2983 struct inode *inode = mapping->host;
2984 int ret = 0, ret2;
2985 handle_t *handle = ext4_journal_current_handle();
2986 loff_t new_i_size;
2987 unsigned long start, end;
2988 int write_mode = (int)(unsigned long)fsdata;
2989
2990 if (write_mode == FALL_BACK_TO_NONDELALLOC)
2991 return ext4_write_end(file, mapping, pos,
2992 len, copied, page, fsdata);
2993
2994 trace_ext4_da_write_end(inode, pos, len, copied);
2995 start = pos & (PAGE_SIZE - 1);
2996 end = start + copied - 1;
2997
2998 /*
2999 * generic_write_end() will run mark_inode_dirty() if i_size
3000 * changes. So let's piggyback the i_disksize mark_inode_dirty
3001 * into that.
3002 */
3003 new_i_size = pos + copied;
3004 if (copied && new_i_size > EXT4_I(inode)->i_disksize) {
3005 if (ext4_has_inline_data(inode) ||
3006 ext4_da_should_update_i_disksize(page, end)) {
3007 ext4_update_i_disksize(inode, new_i_size);
3008 /* We need to mark inode dirty even if
3009 * new_i_size is less that inode->i_size
3010 * bu greater than i_disksize.(hint delalloc)
3011 */
3012 ext4_mark_inode_dirty(handle, inode);
3013 }
3014 }
3015
3016 if (write_mode != CONVERT_INLINE_DATA &&
3017 ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3018 ext4_has_inline_data(inode))
3019 ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied,
3020 page);
3021 else
3022 ret2 = generic_write_end(file, mapping, pos, len, copied,
3023 page, fsdata);
3024
3025 copied = ret2;
3026 if (ret2 < 0)
3027 ret = ret2;
3028 ret2 = ext4_journal_stop(handle);
3029 if (!ret)
3030 ret = ret2;
3031
3032 return ret ? ret : copied;
3033 }
3034
3035 static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
3036 unsigned int length)
3037 {
3038 /*
3039 * Drop reserved blocks
3040 */
3041 BUG_ON(!PageLocked(page));
3042 if (!page_has_buffers(page))
3043 goto out;
3044
3045 ext4_da_page_release_reservation(page, offset, length);
3046
3047 out:
3048 ext4_invalidatepage(page, offset, length);
3049
3050 return;
3051 }
3052
3053 /*
3054 * Force all delayed allocation blocks to be allocated for a given inode.
3055 */
3056 int ext4_alloc_da_blocks(struct inode *inode)
3057 {
3058 trace_ext4_alloc_da_blocks(inode);
3059
3060 if (!EXT4_I(inode)->i_reserved_data_blocks)
3061 return 0;
3062
3063 /*
3064 * We do something simple for now. The filemap_flush() will
3065 * also start triggering a write of the data blocks, which is
3066 * not strictly speaking necessary (and for users of
3067 * laptop_mode, not even desirable). However, to do otherwise
3068 * would require replicating code paths in:
3069 *
3070 * ext4_writepages() ->
3071 * write_cache_pages() ---> (via passed in callback function)
3072 * __mpage_da_writepage() -->
3073 * mpage_add_bh_to_extent()
3074 * mpage_da_map_blocks()
3075 *
3076 * The problem is that write_cache_pages(), located in
3077 * mm/page-writeback.c, marks pages clean in preparation for
3078 * doing I/O, which is not desirable if we're not planning on
3079 * doing I/O at all.
3080 *
3081 * We could call write_cache_pages(), and then redirty all of
3082 * the pages by calling redirty_page_for_writepage() but that
3083 * would be ugly in the extreme. So instead we would need to
3084 * replicate parts of the code in the above functions,
3085 * simplifying them because we wouldn't actually intend to
3086 * write out the pages, but rather only collect contiguous
3087 * logical block extents, call the multi-block allocator, and
3088 * then update the buffer heads with the block allocations.
3089 *
3090 * For now, though, we'll cheat by calling filemap_flush(),
3091 * which will map the blocks, and start the I/O, but not
3092 * actually wait for the I/O to complete.
3093 */
3094 return filemap_flush(inode->i_mapping);
3095 }
3096
3097 /*
3098 * bmap() is special. It gets used by applications such as lilo and by
3099 * the swapper to find the on-disk block of a specific piece of data.
3100 *
3101 * Naturally, this is dangerous if the block concerned is still in the
3102 * journal. If somebody makes a swapfile on an ext4 data-journaling
3103 * filesystem and enables swap, then they may get a nasty shock when the
3104 * data getting swapped to that swapfile suddenly gets overwritten by
3105 * the original zero's written out previously to the journal and
3106 * awaiting writeback in the kernel's buffer cache.
3107 *
3108 * So, if we see any bmap calls here on a modified, data-journaled file,
3109 * take extra steps to flush any blocks which might be in the cache.
3110 */
3111 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3112 {
3113 struct inode *inode = mapping->host;
3114 journal_t *journal;
3115 int err;
3116
3117 /*
3118 * We can get here for an inline file via the FIBMAP ioctl
3119 */
3120 if (ext4_has_inline_data(inode))
3121 return 0;
3122
3123 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3124 test_opt(inode->i_sb, DELALLOC)) {
3125 /*
3126 * With delalloc we want to sync the file
3127 * so that we can make sure we allocate
3128 * blocks for file
3129 */
3130 filemap_write_and_wait(mapping);
3131 }
3132
3133 if (EXT4_JOURNAL(inode) &&
3134 ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3135 /*
3136 * This is a REALLY heavyweight approach, but the use of
3137 * bmap on dirty files is expected to be extremely rare:
3138 * only if we run lilo or swapon on a freshly made file
3139 * do we expect this to happen.
3140 *
3141 * (bmap requires CAP_SYS_RAWIO so this does not
3142 * represent an unprivileged user DOS attack --- we'd be
3143 * in trouble if mortal users could trigger this path at
3144 * will.)
3145 *
3146 * NB. EXT4_STATE_JDATA is not set on files other than
3147 * regular files. If somebody wants to bmap a directory
3148 * or symlink and gets confused because the buffer
3149 * hasn't yet been flushed to disk, they deserve
3150 * everything they get.
3151 */
3152
3153 ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3154 journal = EXT4_JOURNAL(inode);
3155 jbd2_journal_lock_updates(journal);
3156 err = jbd2_journal_flush(journal);
3157 jbd2_journal_unlock_updates(journal);
3158
3159 if (err)
3160 return 0;
3161 }
3162
3163 return generic_block_bmap(mapping, block, ext4_get_block);
3164 }
3165
3166 static int ext4_readpage(struct file *file, struct page *page)
3167 {
3168 int ret = -EAGAIN;
3169 struct inode *inode = page->mapping->host;
3170
3171 trace_ext4_readpage(page);
3172
3173 if (ext4_has_inline_data(inode))
3174 ret = ext4_readpage_inline(inode, page);
3175
3176 if (ret == -EAGAIN)
3177 return ext4_mpage_readpages(page->mapping, NULL, page, 1);
3178
3179 return ret;
3180 }
3181
3182 static int
3183 ext4_readpages(struct file *file, struct address_space *mapping,
3184 struct list_head *pages, unsigned nr_pages)
3185 {
3186 struct inode *inode = mapping->host;
3187
3188 /* If the file has inline data, no need to do readpages. */
3189 if (ext4_has_inline_data(inode))
3190 return 0;
3191
3192 return ext4_mpage_readpages(mapping, pages, NULL, nr_pages);
3193 }
3194
3195 static void ext4_invalidatepage(struct page *page, unsigned int offset,
3196 unsigned int length)
3197 {
3198 trace_ext4_invalidatepage(page, offset, length);
3199
3200 /* No journalling happens on data buffers when this function is used */
3201 WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
3202
3203 block_invalidatepage(page, offset, length);
3204 }
3205
3206 static int __ext4_journalled_invalidatepage(struct page *page,
3207 unsigned int offset,
3208 unsigned int length)
3209 {
3210 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3211
3212 trace_ext4_journalled_invalidatepage(page, offset, length);
3213
3214 /*
3215 * If it's a full truncate we just forget about the pending dirtying
3216 */
3217 if (offset == 0 && length == PAGE_SIZE)
3218 ClearPageChecked(page);
3219
3220 return jbd2_journal_invalidatepage(journal, page, offset, length);
3221 }
3222
3223 /* Wrapper for aops... */
3224 static void ext4_journalled_invalidatepage(struct page *page,
3225 unsigned int offset,
3226 unsigned int length)
3227 {
3228 WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
3229 }
3230
3231 static int ext4_releasepage(struct page *page, gfp_t wait)
3232 {
3233 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3234
3235 trace_ext4_releasepage(page);
3236
3237 /* Page has dirty journalled data -> cannot release */
3238 if (PageChecked(page))
3239 return 0;
3240 if (journal)
3241 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3242 else
3243 return try_to_free_buffers(page);
3244 }
3245
3246 #ifdef CONFIG_FS_DAX
3247 int ext4_dax_mmap_get_block(struct inode *inode, sector_t iblock,
3248 struct buffer_head *bh_result, int create)
3249 {
3250 int ret, err;
3251 int credits;
3252 struct ext4_map_blocks map;
3253 handle_t *handle = NULL;
3254 int flags = 0;
3255
3256 ext4_debug("ext4_dax_mmap_get_block: inode %lu, create flag %d\n",
3257 inode->i_ino, create);
3258 map.m_lblk = iblock;
3259 map.m_len = bh_result->b_size >> inode->i_blkbits;
3260 credits = ext4_chunk_trans_blocks(inode, map.m_len);
3261 if (create) {
3262 flags |= EXT4_GET_BLOCKS_PRE_IO | EXT4_GET_BLOCKS_CREATE_ZERO;
3263 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);
3264 if (IS_ERR(handle)) {
3265 ret = PTR_ERR(handle);
3266 return ret;
3267 }
3268 }
3269
3270 ret = ext4_map_blocks(handle, inode, &map, flags);
3271 if (create) {
3272 err = ext4_journal_stop(handle);
3273 if (ret >= 0 && err < 0)
3274 ret = err;
3275 }
3276 if (ret <= 0)
3277 goto out;
3278 if (map.m_flags & EXT4_MAP_UNWRITTEN) {
3279 int err2;
3280
3281 /*
3282 * We are protected by i_mmap_sem so we know block cannot go
3283 * away from under us even though we dropped i_data_sem.
3284 * Convert extent to written and write zeros there.
3285 *
3286 * Note: We may get here even when create == 0.
3287 */
3288 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);
3289 if (IS_ERR(handle)) {
3290 ret = PTR_ERR(handle);
3291 goto out;
3292 }
3293
3294 err = ext4_map_blocks(handle, inode, &map,
3295 EXT4_GET_BLOCKS_CONVERT | EXT4_GET_BLOCKS_CREATE_ZERO);
3296 if (err < 0)
3297 ret = err;
3298 err2 = ext4_journal_stop(handle);
3299 if (err2 < 0 && ret > 0)
3300 ret = err2;
3301 }
3302 out:
3303 WARN_ON_ONCE(ret == 0 && create);
3304 if (ret > 0) {
3305 map_bh(bh_result, inode->i_sb, map.m_pblk);
3306 /*
3307 * At least for now we have to clear BH_New so that DAX code
3308 * doesn't attempt to zero blocks again in a racy way.
3309 */
3310 map.m_flags &= ~EXT4_MAP_NEW;
3311 ext4_update_bh_state(bh_result, map.m_flags);
3312 bh_result->b_size = map.m_len << inode->i_blkbits;
3313 ret = 0;
3314 }
3315 return ret;
3316 }
3317 #endif
3318
3319 static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3320 ssize_t size, void *private)
3321 {
3322 ext4_io_end_t *io_end = private;
3323
3324 /* if not async direct IO just return */
3325 if (!io_end)
3326 return 0;
3327
3328 ext_debug("ext4_end_io_dio(): io_end 0x%p "
3329 "for inode %lu, iocb 0x%p, offset %llu, size %zd\n",
3330 io_end, io_end->inode->i_ino, iocb, offset, size);
3331
3332 /*
3333 * Error during AIO DIO. We cannot convert unwritten extents as the
3334 * data was not written. Just clear the unwritten flag and drop io_end.
3335 */
3336 if (size <= 0) {
3337 ext4_clear_io_unwritten_flag(io_end);
3338 size = 0;
3339 }
3340 io_end->offset = offset;
3341 io_end->size = size;
3342 ext4_put_io_end(io_end);
3343
3344 return 0;
3345 }
3346
3347 /*
3348 * For ext4 extent files, ext4 will do direct-io write to holes,
3349 * preallocated extents, and those write extend the file, no need to
3350 * fall back to buffered IO.
3351 *
3352 * For holes, we fallocate those blocks, mark them as unwritten
3353 * If those blocks were preallocated, we mark sure they are split, but
3354 * still keep the range to write as unwritten.
3355 *
3356 * The unwritten extents will be converted to written when DIO is completed.
3357 * For async direct IO, since the IO may still pending when return, we
3358 * set up an end_io call back function, which will do the conversion
3359 * when async direct IO completed.
3360 *
3361 * If the O_DIRECT write will extend the file then add this inode to the
3362 * orphan list. So recovery will truncate it back to the original size
3363 * if the machine crashes during the write.
3364 *
3365 */
3366 static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
3367 loff_t offset)
3368 {
3369 struct file *file = iocb->ki_filp;
3370 struct inode *inode = file->f_mapping->host;
3371 ssize_t ret;
3372 size_t count = iov_iter_count(iter);
3373 int overwrite = 0;
3374 get_block_t *get_block_func = NULL;
3375 int dio_flags = 0;
3376 loff_t final_size = offset + count;
3377
3378 /* Use the old path for reads and writes beyond i_size. */
3379 if (iov_iter_rw(iter) != WRITE || final_size > inode->i_size)
3380 return ext4_ind_direct_IO(iocb, iter, offset);
3381
3382 BUG_ON(iocb->private == NULL);
3383
3384 /*
3385 * Make all waiters for direct IO properly wait also for extent
3386 * conversion. This also disallows race between truncate() and
3387 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
3388 */
3389 if (iov_iter_rw(iter) == WRITE)
3390 inode_dio_begin(inode);
3391
3392 /* If we do a overwrite dio, i_mutex locking can be released */
3393 overwrite = *((int *)iocb->private);
3394
3395 if (overwrite)
3396 inode_unlock(inode);
3397
3398 /*
3399 * We could direct write to holes and fallocate.
3400 *
3401 * Allocated blocks to fill the hole are marked as unwritten to prevent
3402 * parallel buffered read to expose the stale data before DIO complete
3403 * the data IO.
3404 *
3405 * As to previously fallocated extents, ext4 get_block will just simply
3406 * mark the buffer mapped but still keep the extents unwritten.
3407 *
3408 * For non AIO case, we will convert those unwritten extents to written
3409 * after return back from blockdev_direct_IO. That way we save us from
3410 * allocating io_end structure and also the overhead of offloading
3411 * the extent convertion to a workqueue.
3412 *
3413 * For async DIO, the conversion needs to be deferred when the
3414 * IO is completed. The ext4 end_io callback function will be
3415 * called to take care of the conversion work. Here for async
3416 * case, we allocate an io_end structure to hook to the iocb.
3417 */
3418 iocb->private = NULL;
3419 if (overwrite)
3420 get_block_func = ext4_dio_get_block_overwrite;
3421 else if (is_sync_kiocb(iocb)) {
3422 get_block_func = ext4_dio_get_block_unwritten_sync;
3423 dio_flags = DIO_LOCKING;
3424 } else {
3425 get_block_func = ext4_dio_get_block_unwritten_async;
3426 dio_flags = DIO_LOCKING;
3427 }
3428 #ifdef CONFIG_EXT4_FS_ENCRYPTION
3429 BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
3430 #endif
3431 if (IS_DAX(inode))
3432 ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
3433 ext4_end_io_dio, dio_flags);
3434 else
3435 ret = __blockdev_direct_IO(iocb, inode,
3436 inode->i_sb->s_bdev, iter, offset,
3437 get_block_func,
3438 ext4_end_io_dio, NULL, dio_flags);
3439
3440 if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
3441 EXT4_STATE_DIO_UNWRITTEN)) {
3442 int err;
3443 /*
3444 * for non AIO case, since the IO is already
3445 * completed, we could do the conversion right here
3446 */
3447 err = ext4_convert_unwritten_extents(NULL, inode,
3448 offset, ret);
3449 if (err < 0)
3450 ret = err;
3451 ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3452 }
3453
3454 if (iov_iter_rw(iter) == WRITE)
3455 inode_dio_end(inode);
3456 /* take i_mutex locking again if we do a ovewrite dio */
3457 if (overwrite)
3458 inode_lock(inode);
3459
3460 return ret;
3461 }
3462
3463 static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
3464 loff_t offset)
3465 {
3466 struct file *file = iocb->ki_filp;
3467 struct inode *inode = file->f_mapping->host;
3468 size_t count = iov_iter_count(iter);
3469 ssize_t ret;
3470
3471 #ifdef CONFIG_EXT4_FS_ENCRYPTION
3472 if (ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode))
3473 return 0;
3474 #endif
3475
3476 /*
3477 * If we are doing data journalling we don't support O_DIRECT
3478 */
3479 if (ext4_should_journal_data(inode))
3480 return 0;
3481
3482 /* Let buffer I/O handle the inline data case. */
3483 if (ext4_has_inline_data(inode))
3484 return 0;
3485
3486 trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
3487 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3488 ret = ext4_ext_direct_IO(iocb, iter, offset);
3489 else
3490 ret = ext4_ind_direct_IO(iocb, iter, offset);
3491 trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
3492 return ret;
3493 }
3494
3495 /*
3496 * Pages can be marked dirty completely asynchronously from ext4's journalling
3497 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
3498 * much here because ->set_page_dirty is called under VFS locks. The page is
3499 * not necessarily locked.
3500 *
3501 * We cannot just dirty the page and leave attached buffers clean, because the
3502 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
3503 * or jbddirty because all the journalling code will explode.
3504 *
3505 * So what we do is to mark the page "pending dirty" and next time writepage
3506 * is called, propagate that into the buffers appropriately.
3507 */
3508 static int ext4_journalled_set_page_dirty(struct page *page)
3509 {
3510 SetPageChecked(page);
3511 return __set_page_dirty_nobuffers(page);
3512 }
3513
3514 static const struct address_space_operations ext4_aops = {
3515 .readpage = ext4_readpage,
3516 .readpages = ext4_readpages,
3517 .writepage = ext4_writepage,
3518 .writepages = ext4_writepages,
3519 .write_begin = ext4_write_begin,
3520 .write_end = ext4_write_end,
3521 .bmap = ext4_bmap,
3522 .invalidatepage = ext4_invalidatepage,
3523 .releasepage = ext4_releasepage,
3524 .direct_IO = ext4_direct_IO,
3525 .migratepage = buffer_migrate_page,
3526 .is_partially_uptodate = block_is_partially_uptodate,
3527 .error_remove_page = generic_error_remove_page,
3528 };
3529
3530 static const struct address_space_operations ext4_journalled_aops = {
3531 .readpage = ext4_readpage,
3532 .readpages = ext4_readpages,
3533 .writepage = ext4_writepage,
3534 .writepages = ext4_writepages,
3535 .write_begin = ext4_write_begin,
3536 .write_end = ext4_journalled_write_end,
3537 .set_page_dirty = ext4_journalled_set_page_dirty,
3538 .bmap = ext4_bmap,
3539 .invalidatepage = ext4_journalled_invalidatepage,
3540 .releasepage = ext4_releasepage,
3541 .direct_IO = ext4_direct_IO,
3542 .is_partially_uptodate = block_is_partially_uptodate,
3543 .error_remove_page = generic_error_remove_page,
3544 };
3545
3546 static const struct address_space_operations ext4_da_aops = {
3547 .readpage = ext4_readpage,
3548 .readpages = ext4_readpages,
3549 .writepage = ext4_writepage,
3550 .writepages = ext4_writepages,
3551 .write_begin = ext4_da_write_begin,
3552 .write_end = ext4_da_write_end,
3553 .bmap = ext4_bmap,
3554 .invalidatepage = ext4_da_invalidatepage,
3555 .releasepage = ext4_releasepage,
3556 .direct_IO = ext4_direct_IO,
3557 .migratepage = buffer_migrate_page,
3558 .is_partially_uptodate = block_is_partially_uptodate,
3559 .error_remove_page = generic_error_remove_page,
3560 };
3561
3562 void ext4_set_aops(struct inode *inode)
3563 {
3564 switch (ext4_inode_journal_mode(inode)) {
3565 case EXT4_INODE_ORDERED_DATA_MODE:
3566 ext4_set_inode_state(inode, EXT4_STATE_ORDERED_MODE);
3567 break;
3568 case EXT4_INODE_WRITEBACK_DATA_MODE:
3569 ext4_clear_inode_state(inode, EXT4_STATE_ORDERED_MODE);
3570 break;
3571 case EXT4_INODE_JOURNAL_DATA_MODE:
3572 inode->i_mapping->a_ops = &ext4_journalled_aops;
3573 return;
3574 default:
3575 BUG();
3576 }
3577 if (test_opt(inode->i_sb, DELALLOC))
3578 inode->i_mapping->a_ops = &ext4_da_aops;
3579 else
3580 inode->i_mapping->a_ops = &ext4_aops;
3581 }
3582
3583 static int __ext4_block_zero_page_range(handle_t *handle,
3584 struct address_space *mapping, loff_t from, loff_t length)
3585 {
3586 ext4_fsblk_t index = from >> PAGE_SHIFT;
3587 unsigned offset = from & (PAGE_SIZE-1);
3588 unsigned blocksize, pos;
3589 ext4_lblk_t iblock;
3590 struct inode *inode = mapping->host;
3591 struct buffer_head *bh;
3592 struct page *page;
3593 int err = 0;
3594
3595 page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3596 mapping_gfp_constraint(mapping, ~__GFP_FS));
3597 if (!page)
3598 return -ENOMEM;
3599
3600 blocksize = inode->i_sb->s_blocksize;
3601
3602 iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3603
3604 if (!page_has_buffers(page))
3605 create_empty_buffers(page, blocksize, 0);
3606
3607 /* Find the buffer that contains "offset" */
3608 bh = page_buffers(page);
3609 pos = blocksize;
3610 while (offset >= pos) {
3611 bh = bh->b_this_page;
3612 iblock++;
3613 pos += blocksize;
3614 }
3615 if (buffer_freed(bh)) {
3616 BUFFER_TRACE(bh, "freed: skip");
3617 goto unlock;
3618 }
3619 if (!buffer_mapped(bh)) {
3620 BUFFER_TRACE(bh, "unmapped");
3621 ext4_get_block(inode, iblock, bh, 0);
3622 /* unmapped? It's a hole - nothing to do */
3623 if (!buffer_mapped(bh)) {
3624 BUFFER_TRACE(bh, "still unmapped");
3625 goto unlock;
3626 }
3627 }
3628
3629 /* Ok, it's mapped. Make sure it's up-to-date */
3630 if (PageUptodate(page))
3631 set_buffer_uptodate(bh);
3632
3633 if (!buffer_uptodate(bh)) {
3634 err = -EIO;
3635 ll_rw_block(READ, 1, &bh);
3636 wait_on_buffer(bh);
3637 /* Uhhuh. Read error. Complain and punt. */
3638 if (!buffer_uptodate(bh))
3639 goto unlock;
3640 if (S_ISREG(inode->i_mode) &&
3641 ext4_encrypted_inode(inode)) {
3642 /* We expect the key to be set. */
3643 BUG_ON(!ext4_has_encryption_key(inode));
3644 BUG_ON(blocksize != PAGE_SIZE);
3645 WARN_ON_ONCE(ext4_decrypt(page));
3646 }
3647 }
3648 if (ext4_should_journal_data(inode)) {
3649 BUFFER_TRACE(bh, "get write access");
3650 err = ext4_journal_get_write_access(handle, bh);
3651 if (err)
3652 goto unlock;
3653 }
3654 zero_user(page, offset, length);
3655 BUFFER_TRACE(bh, "zeroed end of block");
3656
3657 if (ext4_should_journal_data(inode)) {
3658 err = ext4_handle_dirty_metadata(handle, inode, bh);
3659 } else {
3660 err = 0;
3661 mark_buffer_dirty(bh);
3662 if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE))
3663 err = ext4_jbd2_file_inode(handle, inode);
3664 }
3665
3666 unlock:
3667 unlock_page(page);
3668 put_page(page);
3669 return err;
3670 }
3671
3672 /*
3673 * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3674 * starting from file offset 'from'. The range to be zero'd must
3675 * be contained with in one block. If the specified range exceeds
3676 * the end of the block it will be shortened to end of the block
3677 * that cooresponds to 'from'
3678 */
3679 static int ext4_block_zero_page_range(handle_t *handle,
3680 struct address_space *mapping, loff_t from, loff_t length)
3681 {
3682 struct inode *inode = mapping->host;
3683 unsigned offset = from & (PAGE_SIZE-1);
3684 unsigned blocksize = inode->i_sb->s_blocksize;
3685 unsigned max = blocksize - (offset & (blocksize - 1));
3686
3687 /*
3688 * correct length if it does not fall between
3689 * 'from' and the end of the block
3690 */
3691 if (length > max || length < 0)
3692 length = max;
3693
3694 if (IS_DAX(inode))
3695 return dax_zero_page_range(inode, from, length, ext4_get_block);
3696 return __ext4_block_zero_page_range(handle, mapping, from, length);
3697 }
3698
3699 /*
3700 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3701 * up to the end of the block which corresponds to `from'.
3702 * This required during truncate. We need to physically zero the tail end
3703 * of that block so it doesn't yield old data if the file is later grown.
3704 */
3705 static int ext4_block_truncate_page(handle_t *handle,
3706 struct address_space *mapping, loff_t from)
3707 {
3708 unsigned offset = from & (PAGE_SIZE-1);
3709 unsigned length;
3710 unsigned blocksize;
3711 struct inode *inode = mapping->host;
3712
3713 blocksize = inode->i_sb->s_blocksize;
3714 length = blocksize - (offset & (blocksize - 1));
3715
3716 return ext4_block_zero_page_range(handle, mapping, from, length);
3717 }
3718
3719 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3720 loff_t lstart, loff_t length)
3721 {
3722 struct super_block *sb = inode->i_sb;
3723 struct address_space *mapping = inode->i_mapping;
3724 unsigned partial_start, partial_end;
3725 ext4_fsblk_t start, end;
3726 loff_t byte_end = (lstart + length - 1);
3727 int err = 0;
3728
3729 partial_start = lstart & (sb->s_blocksize - 1);
3730 partial_end = byte_end & (sb->s_blocksize - 1);
3731
3732 start = lstart >> sb->s_blocksize_bits;
3733 end = byte_end >> sb->s_blocksize_bits;
3734
3735 /* Handle partial zero within the single block */
3736 if (start == end &&
3737 (partial_start || (partial_end != sb->s_blocksize - 1))) {
3738 err = ext4_block_zero_page_range(handle, mapping,
3739 lstart, length);
3740 return err;
3741 }
3742 /* Handle partial zero out on the start of the range */
3743 if (partial_start) {
3744 err = ext4_block_zero_page_range(handle, mapping,
3745 lstart, sb->s_blocksize);
3746 if (err)
3747 return err;
3748 }
3749 /* Handle partial zero out on the end of the range */
3750 if (partial_end != sb->s_blocksize - 1)
3751 err = ext4_block_zero_page_range(handle, mapping,
3752 byte_end - partial_end,
3753 partial_end + 1);
3754 return err;
3755 }
3756
3757 int ext4_can_truncate(struct inode *inode)
3758 {
3759 if (S_ISREG(inode->i_mode))
3760 return 1;
3761 if (S_ISDIR(inode->i_mode))
3762 return 1;
3763 if (S_ISLNK(inode->i_mode))
3764 return !ext4_inode_is_fast_symlink(inode);
3765 return 0;
3766 }
3767
3768 /*
3769 * We have to make sure i_disksize gets properly updated before we truncate
3770 * page cache due to hole punching or zero range. Otherwise i_disksize update
3771 * can get lost as it may have been postponed to submission of writeback but
3772 * that will never happen after we truncate page cache.
3773 */
3774 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3775 loff_t len)
3776 {
3777 handle_t *handle;
3778 loff_t size = i_size_read(inode);
3779
3780 WARN_ON(!inode_is_locked(inode));
3781 if (offset > size || offset + len < size)
3782 return 0;
3783
3784 if (EXT4_I(inode)->i_disksize >= size)
3785 return 0;
3786
3787 handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3788 if (IS_ERR(handle))
3789 return PTR_ERR(handle);
3790 ext4_update_i_disksize(inode, size);
3791 ext4_mark_inode_dirty(handle, inode);
3792 ext4_journal_stop(handle);
3793
3794 return 0;
3795 }
3796
3797 /*
3798 * ext4_punch_hole: punches a hole in a file by releaseing the blocks
3799 * associated with the given offset and length
3800 *
3801 * @inode: File inode
3802 * @offset: The offset where the hole will begin
3803 * @len: The length of the hole
3804 *
3805 * Returns: 0 on success or negative on failure
3806 */
3807
3808 int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
3809 {
3810 struct super_block *sb = inode->i_sb;
3811 ext4_lblk_t first_block, stop_block;
3812 struct address_space *mapping = inode->i_mapping;
3813 loff_t first_block_offset, last_block_offset;
3814 handle_t *handle;
3815 unsigned int credits;
3816 int ret = 0;
3817
3818 if (!S_ISREG(inode->i_mode))
3819 return -EOPNOTSUPP;
3820
3821 trace_ext4_punch_hole(inode, offset, length, 0);
3822
3823 /*
3824 * Write out all dirty pages to avoid race conditions
3825 * Then release them.
3826 */
3827 if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3828 ret = filemap_write_and_wait_range(mapping, offset,
3829 offset + length - 1);
3830 if (ret)
3831 return ret;
3832 }
3833
3834 inode_lock(inode);
3835
3836 /* No need to punch hole beyond i_size */
3837 if (offset >= inode->i_size)
3838 goto out_mutex;
3839
3840 /*
3841 * If the hole extends beyond i_size, set the hole
3842 * to end after the page that contains i_size
3843 */
3844 if (offset + length > inode->i_size) {
3845 length = inode->i_size +
3846 PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
3847 offset;
3848 }
3849
3850 if (offset & (sb->s_blocksize - 1) ||
3851 (offset + length) & (sb->s_blocksize - 1)) {
3852 /*
3853 * Attach jinode to inode for jbd2 if we do any zeroing of
3854 * partial block
3855 */
3856 ret = ext4_inode_attach_jinode(inode);
3857 if (ret < 0)
3858 goto out_mutex;
3859
3860 }
3861
3862 /* Wait all existing dio workers, newcomers will block on i_mutex */
3863 ext4_inode_block_unlocked_dio(inode);
3864 inode_dio_wait(inode);
3865
3866 /*
3867 * Prevent page faults from reinstantiating pages we have released from
3868 * page cache.
3869 */
3870 down_write(&EXT4_I(inode)->i_mmap_sem);
3871 first_block_offset = round_up(offset, sb->s_blocksize);
3872 last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
3873
3874 /* Now release the pages and zero block aligned part of pages*/
3875 if (last_block_offset > first_block_offset) {
3876 ret = ext4_update_disksize_before_punch(inode, offset, length);
3877 if (ret)
3878 goto out_dio;
3879 truncate_pagecache_range(inode, first_block_offset,
3880 last_block_offset);
3881 }
3882
3883 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3884 credits = ext4_writepage_trans_blocks(inode);
3885 else
3886 credits = ext4_blocks_for_truncate(inode);
3887 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
3888 if (IS_ERR(handle)) {
3889 ret = PTR_ERR(handle);
3890 ext4_std_error(sb, ret);
3891 goto out_dio;
3892 }
3893
3894 ret = ext4_zero_partial_blocks(handle, inode, offset,
3895 length);
3896 if (ret)
3897 goto out_stop;
3898
3899 first_block = (offset + sb->s_blocksize - 1) >>
3900 EXT4_BLOCK_SIZE_BITS(sb);
3901 stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
3902
3903 /* If there are no blocks to remove, return now */
3904 if (first_block >= stop_block)
3905 goto out_stop;
3906
3907 down_write(&EXT4_I(inode)->i_data_sem);
3908 ext4_discard_preallocations(inode);
3909
3910 ret = ext4_es_remove_extent(inode, first_block,
3911 stop_block - first_block);
3912 if (ret) {
3913 up_write(&EXT4_I(inode)->i_data_sem);
3914 goto out_stop;
3915 }
3916
3917 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3918 ret = ext4_ext_remove_space(inode, first_block,
3919 stop_block - 1);
3920 else
3921 ret = ext4_ind_remove_space(handle, inode, first_block,
3922 stop_block);
3923
3924 up_write(&EXT4_I(inode)->i_data_sem);
3925 if (IS_SYNC(inode))
3926 ext4_handle_sync(handle);
3927
3928 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3929 ext4_mark_inode_dirty(handle, inode);
3930 out_stop:
3931 ext4_journal_stop(handle);
3932 out_dio:
3933 up_write(&EXT4_I(inode)->i_mmap_sem);
3934 ext4_inode_resume_unlocked_dio(inode);
3935 out_mutex:
3936 inode_unlock(inode);
3937 return ret;
3938 }
3939
3940 int ext4_inode_attach_jinode(struct inode *inode)
3941 {
3942 struct ext4_inode_info *ei = EXT4_I(inode);
3943 struct jbd2_inode *jinode;
3944
3945 if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
3946 return 0;
3947
3948 jinode = jbd2_alloc_inode(GFP_KERNEL);
3949 spin_lock(&inode->i_lock);
3950 if (!ei->jinode) {
3951 if (!jinode) {
3952 spin_unlock(&inode->i_lock);
3953 return -ENOMEM;
3954 }
3955 ei->jinode = jinode;
3956 jbd2_journal_init_jbd_inode(ei->jinode, inode);
3957 jinode = NULL;
3958 }
3959 spin_unlock(&inode->i_lock);
3960 if (unlikely(jinode != NULL))
3961 jbd2_free_inode(jinode);
3962 return 0;
3963 }
3964
3965 /*
3966 * ext4_truncate()
3967 *
3968 * We block out ext4_get_block() block instantiations across the entire
3969 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3970 * simultaneously on behalf of the same inode.
3971 *
3972 * As we work through the truncate and commit bits of it to the journal there
3973 * is one core, guiding principle: the file's tree must always be consistent on
3974 * disk. We must be able to restart the truncate after a crash.
3975 *
3976 * The file's tree may be transiently inconsistent in memory (although it
3977 * probably isn't), but whenever we close off and commit a journal transaction,
3978 * the contents of (the filesystem + the journal) must be consistent and
3979 * restartable. It's pretty simple, really: bottom up, right to left (although
3980 * left-to-right works OK too).
3981 *
3982 * Note that at recovery time, journal replay occurs *before* the restart of
3983 * truncate against the orphan inode list.
3984 *
3985 * The committed inode has the new, desired i_size (which is the same as
3986 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
3987 * that this inode's truncate did not complete and it will again call
3988 * ext4_truncate() to have another go. So there will be instantiated blocks
3989 * to the right of the truncation point in a crashed ext4 filesystem. But
3990 * that's fine - as long as they are linked from the inode, the post-crash
3991 * ext4_truncate() run will find them and release them.
3992 */
3993 void ext4_truncate(struct inode *inode)
3994 {
3995 struct ext4_inode_info *ei = EXT4_I(inode);
3996 unsigned int credits;
3997 handle_t *handle;
3998 struct address_space *mapping = inode->i_mapping;
3999
4000 /*
4001 * There is a possibility that we're either freeing the inode
4002 * or it's a completely new inode. In those cases we might not
4003 * have i_mutex locked because it's not necessary.
4004 */
4005 if (!(inode->i_state & (I_NEW|I_FREEING)))
4006 WARN_ON(!inode_is_locked(inode));
4007 trace_ext4_truncate_enter(inode);
4008
4009 if (!ext4_can_truncate(inode))
4010 return;
4011
4012 ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4013
4014 if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4015 ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4016
4017 if (ext4_has_inline_data(inode)) {
4018 int has_inline = 1;
4019
4020 ext4_inline_data_truncate(inode, &has_inline);
4021 if (has_inline)
4022 return;
4023 }
4024
4025 /* If we zero-out tail of the page, we have to create jinode for jbd2 */
4026 if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4027 if (ext4_inode_attach_jinode(inode) < 0)
4028 return;
4029 }
4030
4031 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4032 credits = ext4_writepage_trans_blocks(inode);
4033 else
4034 credits = ext4_blocks_for_truncate(inode);
4035
4036 handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4037 if (IS_ERR(handle)) {
4038 ext4_std_error(inode->i_sb, PTR_ERR(handle));
4039 return;
4040 }
4041
4042 if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4043 ext4_block_truncate_page(handle, mapping, inode->i_size);
4044
4045 /*
4046 * We add the inode to the orphan list, so that if this
4047 * truncate spans multiple transactions, and we crash, we will
4048 * resume the truncate when the filesystem recovers. It also
4049 * marks the inode dirty, to catch the new size.
4050 *
4051 * Implication: the file must always be in a sane, consistent
4052 * truncatable state while each transaction commits.
4053 */
4054 if (ext4_orphan_add(handle, inode))
4055 goto out_stop;
4056
4057 down_write(&EXT4_I(inode)->i_data_sem);
4058
4059 ext4_discard_preallocations(inode);
4060
4061 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4062 ext4_ext_truncate(handle, inode);
4063 else
4064 ext4_ind_truncate(handle, inode);
4065
4066 up_write(&ei->i_data_sem);
4067
4068 if (IS_SYNC(inode))
4069 ext4_handle_sync(handle);
4070
4071 out_stop:
4072 /*
4073 * If this was a simple ftruncate() and the file will remain alive,
4074 * then we need to clear up the orphan record which we created above.
4075 * However, if this was a real unlink then we were called by
4076 * ext4_evict_inode(), and we allow that function to clean up the
4077 * orphan info for us.
4078 */
4079 if (inode->i_nlink)
4080 ext4_orphan_del(handle, inode);
4081
4082 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4083 ext4_mark_inode_dirty(handle, inode);
4084 ext4_journal_stop(handle);
4085
4086 trace_ext4_truncate_exit(inode);
4087 }
4088
4089 /*
4090 * ext4_get_inode_loc returns with an extra refcount against the inode's
4091 * underlying buffer_head on success. If 'in_mem' is true, we have all
4092 * data in memory that is needed to recreate the on-disk version of this
4093 * inode.
4094 */
4095 static int __ext4_get_inode_loc(struct inode *inode,
4096 struct ext4_iloc *iloc, int in_mem)
4097 {
4098 struct ext4_group_desc *gdp;
4099 struct buffer_head *bh;
4100 struct super_block *sb = inode->i_sb;
4101 ext4_fsblk_t block;
4102 int inodes_per_block, inode_offset;
4103
4104 iloc->bh = NULL;
4105 if (!ext4_valid_inum(sb, inode->i_ino))
4106 return -EFSCORRUPTED;
4107
4108 iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4109 gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4110 if (!gdp)
4111 return -EIO;
4112
4113 /*
4114 * Figure out the offset within the block group inode table
4115 */
4116 inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4117 inode_offset = ((inode->i_ino - 1) %
4118 EXT4_INODES_PER_GROUP(sb));
4119 block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4120 iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4121
4122 bh = sb_getblk(sb, block);
4123 if (unlikely(!bh))
4124 return -ENOMEM;
4125 if (!buffer_uptodate(bh)) {
4126 lock_buffer(bh);
4127
4128 /*
4129 * If the buffer has the write error flag, we have failed
4130 * to write out another inode in the same block. In this
4131 * case, we don't have to read the block because we may
4132 * read the old inode data successfully.
4133 */
4134 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4135 set_buffer_uptodate(bh);
4136
4137 if (buffer_uptodate(bh)) {
4138 /* someone brought it uptodate while we waited */
4139 unlock_buffer(bh);
4140 goto has_buffer;
4141 }
4142
4143 /*
4144 * If we have all information of the inode in memory and this
4145 * is the only valid inode in the block, we need not read the
4146 * block.
4147 */
4148 if (in_mem) {
4149 struct buffer_head *bitmap_bh;
4150 int i, start;
4151
4152 start = inode_offset & ~(inodes_per_block - 1);
4153
4154 /* Is the inode bitmap in cache? */
4155 bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4156 if (unlikely(!bitmap_bh))
4157 goto make_io;
4158
4159 /*
4160 * If the inode bitmap isn't in cache then the
4161 * optimisation may end up performing two reads instead
4162 * of one, so skip it.
4163 */
4164 if (!buffer_uptodate(bitmap_bh)) {
4165 brelse(bitmap_bh);
4166 goto make_io;
4167 }
4168 for (i = start; i < start + inodes_per_block; i++) {
4169 if (i == inode_offset)
4170 continue;
4171 if (ext4_test_bit(i, bitmap_bh->b_data))
4172 break;
4173 }
4174 brelse(bitmap_bh);
4175 if (i == start + inodes_per_block) {
4176 /* all other inodes are free, so skip I/O */
4177 memset(bh->b_data, 0, bh->b_size);
4178 set_buffer_uptodate(bh);
4179 unlock_buffer(bh);
4180 goto has_buffer;
4181 }
4182 }
4183
4184 make_io:
4185 /*
4186 * If we need to do any I/O, try to pre-readahead extra
4187 * blocks from the inode table.
4188 */
4189 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4190 ext4_fsblk_t b, end, table;
4191 unsigned num;
4192 __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4193
4194 table = ext4_inode_table(sb, gdp);
4195 /* s_inode_readahead_blks is always a power of 2 */
4196 b = block & ~((ext4_fsblk_t) ra_blks - 1);
4197 if (table > b)
4198 b = table;
4199 end = b + ra_blks;
4200 num = EXT4_INODES_PER_GROUP(sb);
4201 if (ext4_has_group_desc_csum(sb))
4202 num -= ext4_itable_unused_count(sb, gdp);
4203 table += num / inodes_per_block;
4204 if (end > table)
4205 end = table;
4206 while (b <= end)
4207 sb_breadahead(sb, b++);
4208 }
4209
4210 /*
4211 * There are other valid inodes in the buffer, this inode
4212 * has in-inode xattrs, or we don't have this inode in memory.
4213 * Read the block from disk.
4214 */
4215 trace_ext4_load_inode(inode);
4216 get_bh(bh);
4217 bh->b_end_io = end_buffer_read_sync;
4218 submit_bh(READ | REQ_META | REQ_PRIO, bh);
4219 wait_on_buffer(bh);
4220 if (!buffer_uptodate(bh)) {
4221 EXT4_ERROR_INODE_BLOCK(inode, block,
4222 "unable to read itable block");
4223 brelse(bh);
4224 return -EIO;
4225 }
4226 }
4227 has_buffer:
4228 iloc->bh = bh;
4229 return 0;
4230 }
4231
4232 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4233 {
4234 /* We have all inode data except xattrs in memory here. */
4235 return __ext4_get_inode_loc(inode, iloc,
4236 !ext4_test_inode_state(inode, EXT4_STATE_XATTR));
4237 }
4238
4239 void ext4_set_inode_flags(struct inode *inode)
4240 {
4241 unsigned int flags = EXT4_I(inode)->i_flags;
4242 unsigned int new_fl = 0;
4243
4244 if (flags & EXT4_SYNC_FL)
4245 new_fl |= S_SYNC;
4246 if (flags & EXT4_APPEND_FL)
4247 new_fl |= S_APPEND;
4248 if (flags & EXT4_IMMUTABLE_FL)
4249 new_fl |= S_IMMUTABLE;
4250 if (flags & EXT4_NOATIME_FL)
4251 new_fl |= S_NOATIME;
4252 if (flags & EXT4_DIRSYNC_FL)
4253 new_fl |= S_DIRSYNC;
4254 if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
4255 new_fl |= S_DAX;
4256 inode_set_flags(inode, new_fl,
4257 S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX);
4258 }
4259
4260 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4261 void ext4_get_inode_flags(struct ext4_inode_info *ei)
4262 {
4263 unsigned int vfs_fl;
4264 unsigned long old_fl, new_fl;
4265
4266 do {
4267 vfs_fl = ei->vfs_inode.i_flags;
4268 old_fl = ei->i_flags;
4269 new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4270 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|
4271 EXT4_DIRSYNC_FL);
4272 if (vfs_fl & S_SYNC)
4273 new_fl |= EXT4_SYNC_FL;
4274 if (vfs_fl & S_APPEND)
4275 new_fl |= EXT4_APPEND_FL;
4276 if (vfs_fl & S_IMMUTABLE)
4277 new_fl |= EXT4_IMMUTABLE_FL;
4278 if (vfs_fl & S_NOATIME)
4279 new_fl |= EXT4_NOATIME_FL;
4280 if (vfs_fl & S_DIRSYNC)
4281 new_fl |= EXT4_DIRSYNC_FL;
4282 } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl);
4283 }
4284
4285 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4286 struct ext4_inode_info *ei)
4287 {
4288 blkcnt_t i_blocks ;
4289 struct inode *inode = &(ei->vfs_inode);
4290 struct super_block *sb = inode->i_sb;
4291
4292 if (ext4_has_feature_huge_file(sb)) {
4293 /* we are using combined 48 bit field */
4294 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4295 le32_to_cpu(raw_inode->i_blocks_lo);
4296 if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4297 /* i_blocks represent file system block size */
4298 return i_blocks << (inode->i_blkbits - 9);
4299 } else {
4300 return i_blocks;
4301 }
4302 } else {
4303 return le32_to_cpu(raw_inode->i_blocks_lo);
4304 }
4305 }
4306
4307 static inline void ext4_iget_extra_inode(struct inode *inode,
4308 struct ext4_inode *raw_inode,
4309 struct ext4_inode_info *ei)
4310 {
4311 __le32 *magic = (void *)raw_inode +
4312 EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4313 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4314 ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4315 ext4_find_inline_data_nolock(inode);
4316 } else
4317 EXT4_I(inode)->i_inline_off = 0;
4318 }
4319
4320 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4321 {
4322 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, EXT4_FEATURE_RO_COMPAT_PROJECT))
4323 return -EOPNOTSUPP;
4324 *projid = EXT4_I(inode)->i_projid;
4325 return 0;
4326 }
4327
4328 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4329 {
4330 struct ext4_iloc iloc;
4331 struct ext4_inode *raw_inode;
4332 struct ext4_inode_info *ei;
4333 struct inode *inode;
4334 journal_t *journal = EXT4_SB(sb)->s_journal;
4335 long ret;
4336 int block;
4337 uid_t i_uid;
4338 gid_t i_gid;
4339 projid_t i_projid;
4340
4341 inode = iget_locked(sb, ino);
4342 if (!inode)
4343 return ERR_PTR(-ENOMEM);
4344 if (!(inode->i_state & I_NEW))
4345 return inode;
4346
4347 ei = EXT4_I(inode);
4348 iloc.bh = NULL;
4349
4350 ret = __ext4_get_inode_loc(inode, &iloc, 0);
4351 if (ret < 0)
4352 goto bad_inode;
4353 raw_inode = ext4_raw_inode(&iloc);
4354
4355 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4356 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4357 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4358 EXT4_INODE_SIZE(inode->i_sb)) {
4359 EXT4_ERROR_INODE(inode, "bad extra_isize (%u != %u)",
4360 EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize,
4361 EXT4_INODE_SIZE(inode->i_sb));
4362 ret = -EFSCORRUPTED;
4363 goto bad_inode;
4364 }
4365 } else
4366 ei->i_extra_isize = 0;
4367
4368 /* Precompute checksum seed for inode metadata */
4369 if (ext4_has_metadata_csum(sb)) {
4370 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4371 __u32 csum;
4372 __le32 inum = cpu_to_le32(inode->i_ino);
4373 __le32 gen = raw_inode->i_generation;
4374 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4375 sizeof(inum));
4376 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4377 sizeof(gen));
4378 }
4379
4380 if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
4381 EXT4_ERROR_INODE(inode, "checksum invalid");
4382 ret = -EFSBADCRC;
4383 goto bad_inode;
4384 }
4385
4386 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4387 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4388 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4389 if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_PROJECT) &&
4390 EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4391 EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4392 i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4393 else
4394 i_projid = EXT4_DEF_PROJID;
4395
4396 if (!(test_opt(inode->i_sb, NO_UID32))) {
4397 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4398 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4399 }
4400 i_uid_write(inode, i_uid);
4401 i_gid_write(inode, i_gid);
4402 ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4403 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4404
4405 ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
4406 ei->i_inline_off = 0;
4407 ei->i_dir_start_lookup = 0;
4408 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4409 /* We now have enough fields to check if the inode was active or not.
4410 * This is needed because nfsd might try to access dead inodes
4411 * the test is that same one that e2fsck uses
4412 * NeilBrown 1999oct15
4413 */
4414 if (inode->i_nlink == 0) {
4415 if ((inode->i_mode == 0 ||
4416 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4417 ino != EXT4_BOOT_LOADER_INO) {
4418 /* this inode is deleted */
4419 ret = -ESTALE;
4420 goto bad_inode;
4421 }
4422 /* The only unlinked inodes we let through here have
4423 * valid i_mode and are being read by the orphan
4424 * recovery code: that's fine, we're about to complete
4425 * the process of deleting those.
4426 * OR it is the EXT4_BOOT_LOADER_INO which is
4427 * not initialized on a new filesystem. */
4428 }
4429 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4430 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4431 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4432 if (ext4_has_feature_64bit(sb))
4433 ei->i_file_acl |=
4434 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4435 inode->i_size = ext4_isize(raw_inode);
4436 ei->i_disksize = inode->i_size;
4437 #ifdef CONFIG_QUOTA
4438 ei->i_reserved_quota = 0;
4439 #endif
4440 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4441 ei->i_block_group = iloc.block_group;
4442 ei->i_last_alloc_group = ~0;
4443 /*
4444 * NOTE! The in-memory inode i_data array is in little-endian order
4445 * even on big-endian machines: we do NOT byteswap the block numbers!
4446 */
4447 for (block = 0; block < EXT4_N_BLOCKS; block++)
4448 ei->i_data[block] = raw_inode->i_block[block];
4449 INIT_LIST_HEAD(&ei->i_orphan);
4450
4451 /*
4452 * Set transaction id's of transactions that have to be committed
4453 * to finish f[data]sync. We set them to currently running transaction
4454 * as we cannot be sure that the inode or some of its metadata isn't
4455 * part of the transaction - the inode could have been reclaimed and
4456 * now it is reread from disk.
4457 */
4458 if (journal) {
4459 transaction_t *transaction;
4460 tid_t tid;
4461
4462 read_lock(&journal->j_state_lock);
4463 if (journal->j_running_transaction)
4464 transaction = journal->j_running_transaction;
4465 else
4466 transaction = journal->j_committing_transaction;
4467 if (transaction)
4468 tid = transaction->t_tid;
4469 else
4470 tid = journal->j_commit_sequence;
4471 read_unlock(&journal->j_state_lock);
4472 ei->i_sync_tid = tid;
4473 ei->i_datasync_tid = tid;
4474 }
4475
4476 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4477 if (ei->i_extra_isize == 0) {
4478 /* The extra space is currently unused. Use it. */
4479 ei->i_extra_isize = sizeof(struct ext4_inode) -
4480 EXT4_GOOD_OLD_INODE_SIZE;
4481 } else {
4482 ext4_iget_extra_inode(inode, raw_inode, ei);
4483 }
4484 }
4485
4486 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4487 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4488 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4489 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4490
4491 if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4492 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4493 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4494 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4495 inode->i_version |=
4496 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4497 }
4498 }
4499
4500 ret = 0;
4501 if (ei->i_file_acl &&
4502 !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
4503 EXT4_ERROR_INODE(inode, "bad extended attribute block %llu",
4504 ei->i_file_acl);
4505 ret = -EFSCORRUPTED;
4506 goto bad_inode;
4507 } else if (!ext4_has_inline_data(inode)) {
4508 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
4509 if ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4510 (S_ISLNK(inode->i_mode) &&
4511 !ext4_inode_is_fast_symlink(inode))))
4512 /* Validate extent which is part of inode */
4513 ret = ext4_ext_check_inode(inode);
4514 } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4515 (S_ISLNK(inode->i_mode) &&
4516 !ext4_inode_is_fast_symlink(inode))) {
4517 /* Validate block references which are part of inode */
4518 ret = ext4_ind_check_inode(inode);
4519 }
4520 }
4521 if (ret)
4522 goto bad_inode;
4523
4524 if (S_ISREG(inode->i_mode)) {
4525 inode->i_op = &ext4_file_inode_operations;
4526 inode->i_fop = &ext4_file_operations;
4527 ext4_set_aops(inode);
4528 } else if (S_ISDIR(inode->i_mode)) {
4529 inode->i_op = &ext4_dir_inode_operations;
4530 inode->i_fop = &ext4_dir_operations;
4531 } else if (S_ISLNK(inode->i_mode)) {
4532 if (ext4_encrypted_inode(inode)) {
4533 inode->i_op = &ext4_encrypted_symlink_inode_operations;
4534 ext4_set_aops(inode);
4535 } else if (ext4_inode_is_fast_symlink(inode)) {
4536 inode->i_link = (char *)ei->i_data;
4537 inode->i_op = &ext4_fast_symlink_inode_operations;
4538 nd_terminate_link(ei->i_data, inode->i_size,
4539 sizeof(ei->i_data) - 1);
4540 } else {
4541 inode->i_op = &ext4_symlink_inode_operations;
4542 ext4_set_aops(inode);
4543 }
4544 inode_nohighmem(inode);
4545 } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4546 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4547 inode->i_op = &ext4_special_inode_operations;
4548 if (raw_inode->i_block[0])
4549 init_special_inode(inode, inode->i_mode,
4550 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4551 else
4552 init_special_inode(inode, inode->i_mode,
4553 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4554 } else if (ino == EXT4_BOOT_LOADER_INO) {
4555 make_bad_inode(inode);
4556 } else {
4557 ret = -EFSCORRUPTED;
4558 EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode);
4559 goto bad_inode;
4560 }
4561 brelse(iloc.bh);
4562 ext4_set_inode_flags(inode);
4563 unlock_new_inode(inode);
4564 return inode;
4565
4566 bad_inode:
4567 brelse(iloc.bh);
4568 iget_failed(inode);
4569 return ERR_PTR(ret);
4570 }
4571
4572 struct inode *ext4_iget_normal(struct super_block *sb, unsigned long ino)
4573 {
4574 if (ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO)
4575 return ERR_PTR(-EFSCORRUPTED);
4576 return ext4_iget(sb, ino);
4577 }
4578
4579 static int ext4_inode_blocks_set(handle_t *handle,
4580 struct ext4_inode *raw_inode,
4581 struct ext4_inode_info *ei)
4582 {
4583 struct inode *inode = &(ei->vfs_inode);
4584 u64 i_blocks = inode->i_blocks;
4585 struct super_block *sb = inode->i_sb;
4586
4587 if (i_blocks <= ~0U) {
4588 /*
4589 * i_blocks can be represented in a 32 bit variable
4590 * as multiple of 512 bytes
4591 */
4592 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4593 raw_inode->i_blocks_high = 0;
4594 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4595 return 0;
4596 }
4597 if (!ext4_has_feature_huge_file(sb))
4598 return -EFBIG;
4599
4600 if (i_blocks <= 0xffffffffffffULL) {
4601 /*
4602 * i_blocks can be represented in a 48 bit variable
4603 * as multiple of 512 bytes
4604 */
4605 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4606 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4607 ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4608 } else {
4609 ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4610 /* i_block is stored in file system block size */
4611 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4612 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4613 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4614 }
4615 return 0;
4616 }
4617
4618 struct other_inode {
4619 unsigned long orig_ino;
4620 struct ext4_inode *raw_inode;
4621 };
4622
4623 static int other_inode_match(struct inode * inode, unsigned long ino,
4624 void *data)
4625 {
4626 struct other_inode *oi = (struct other_inode *) data;
4627
4628 if ((inode->i_ino != ino) ||
4629 (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4630 I_DIRTY_SYNC | I_DIRTY_DATASYNC)) ||
4631 ((inode->i_state & I_DIRTY_TIME) == 0))
4632 return 0;
4633 spin_lock(&inode->i_lock);
4634 if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
4635 I_DIRTY_SYNC | I_DIRTY_DATASYNC)) == 0) &&
4636 (inode->i_state & I_DIRTY_TIME)) {
4637 struct ext4_inode_info *ei = EXT4_I(inode);
4638
4639 inode->i_state &= ~(I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED);
4640 spin_unlock(&inode->i_lock);
4641
4642 spin_lock(&ei->i_raw_lock);
4643 EXT4_INODE_SET_XTIME(i_ctime, inode, oi->raw_inode);
4644 EXT4_INODE_SET_XTIME(i_mtime, inode, oi->raw_inode);
4645 EXT4_INODE_SET_XTIME(i_atime, inode, oi->raw_inode);
4646 ext4_inode_csum_set(inode, oi->raw_inode, ei);
4647 spin_unlock(&ei->i_raw_lock);
4648 trace_ext4_other_inode_update_time(inode, oi->orig_ino);
4649 return -1;
4650 }
4651 spin_unlock(&inode->i_lock);
4652 return -1;
4653 }
4654
4655 /*
4656 * Opportunistically update the other time fields for other inodes in
4657 * the same inode table block.
4658 */
4659 static void ext4_update_other_inodes_time(struct super_block *sb,
4660 unsigned long orig_ino, char *buf)
4661 {
4662 struct other_inode oi;
4663 unsigned long ino;
4664 int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4665 int inode_size = EXT4_INODE_SIZE(sb);
4666
4667 oi.orig_ino = orig_ino;
4668 /*
4669 * Calculate the first inode in the inode table block. Inode
4670 * numbers are one-based. That is, the first inode in a block
4671 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
4672 */
4673 ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
4674 for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
4675 if (ino == orig_ino)
4676 continue;
4677 oi.raw_inode = (struct ext4_inode *) buf;
4678 (void) find_inode_nowait(sb, ino, other_inode_match, &oi);
4679 }
4680 }
4681
4682 /*
4683 * Post the struct inode info into an on-disk inode location in the
4684 * buffer-cache. This gobbles the caller's reference to the
4685 * buffer_head in the inode location struct.
4686 *
4687 * The caller must have write access to iloc->bh.
4688 */
4689 static int ext4_do_update_inode(handle_t *handle,
4690 struct inode *inode,
4691 struct ext4_iloc *iloc)
4692 {
4693 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4694 struct ext4_inode_info *ei = EXT4_I(inode);
4695 struct buffer_head *bh = iloc->bh;
4696 struct super_block *sb = inode->i_sb;
4697 int err = 0, rc, block;
4698 int need_datasync = 0, set_large_file = 0;
4699 uid_t i_uid;
4700 gid_t i_gid;
4701 projid_t i_projid;
4702
4703 spin_lock(&ei->i_raw_lock);
4704
4705 /* For fields not tracked in the in-memory inode,
4706 * initialise them to zero for new inodes. */
4707 if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
4708 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4709
4710 ext4_get_inode_flags(ei);
4711 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4712 i_uid = i_uid_read(inode);
4713 i_gid = i_gid_read(inode);
4714 i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4715 if (!(test_opt(inode->i_sb, NO_UID32))) {
4716 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4717 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4718 /*
4719 * Fix up interoperability with old kernels. Otherwise, old inodes get
4720 * re-used with the upper 16 bits of the uid/gid intact
4721 */
4722 if (!ei->i_dtime) {
4723 raw_inode->i_uid_high =
4724 cpu_to_le16(high_16_bits(i_uid));
4725 raw_inode->i_gid_high =
4726 cpu_to_le16(high_16_bits(i_gid));
4727 } else {
4728 raw_inode->i_uid_high = 0;
4729 raw_inode->i_gid_high = 0;
4730 }
4731 } else {
4732 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4733 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4734 raw_inode->i_uid_high = 0;
4735 raw_inode->i_gid_high = 0;
4736 }
4737 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4738
4739 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4740 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4741 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4742 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4743
4744 err = ext4_inode_blocks_set(handle, raw_inode, ei);
4745 if (err) {
4746 spin_unlock(&ei->i_raw_lock);
4747 goto out_brelse;
4748 }
4749 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4750 raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4751 if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4752 raw_inode->i_file_acl_high =
4753 cpu_to_le16(ei->i_file_acl >> 32);
4754 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4755 if (ei->i_disksize != ext4_isize(raw_inode)) {
4756 ext4_isize_set(raw_inode, ei->i_disksize);
4757 need_datasync = 1;
4758 }
4759 if (ei->i_disksize > 0x7fffffffULL) {
4760 if (!ext4_has_feature_large_file(sb) ||
4761 EXT4_SB(sb)->s_es->s_rev_level ==
4762 cpu_to_le32(EXT4_GOOD_OLD_REV))
4763 set_large_file = 1;
4764 }
4765 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4766 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4767 if (old_valid_dev(inode->i_rdev)) {
4768 raw_inode->i_block[0] =
4769 cpu_to_le32(old_encode_dev(inode->i_rdev));
4770 raw_inode->i_block[1] = 0;
4771 } else {
4772 raw_inode->i_block[0] = 0;
4773 raw_inode->i_block[1] =
4774 cpu_to_le32(new_encode_dev(inode->i_rdev));
4775 raw_inode->i_block[2] = 0;
4776 }
4777 } else if (!ext4_has_inline_data(inode)) {
4778 for (block = 0; block < EXT4_N_BLOCKS; block++)
4779 raw_inode->i_block[block] = ei->i_data[block];
4780 }
4781
4782 if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4783 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4784 if (ei->i_extra_isize) {
4785 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4786 raw_inode->i_version_hi =
4787 cpu_to_le32(inode->i_version >> 32);
4788 raw_inode->i_extra_isize =
4789 cpu_to_le16(ei->i_extra_isize);
4790 }
4791 }
4792
4793 BUG_ON(!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
4794 EXT4_FEATURE_RO_COMPAT_PROJECT) &&
4795 i_projid != EXT4_DEF_PROJID);
4796
4797 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4798 EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4799 raw_inode->i_projid = cpu_to_le32(i_projid);
4800
4801 ext4_inode_csum_set(inode, raw_inode, ei);
4802 spin_unlock(&ei->i_raw_lock);
4803 if (inode->i_sb->s_flags & MS_LAZYTIME)
4804 ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
4805 bh->b_data);
4806
4807 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4808 rc = ext4_handle_dirty_metadata(handle, NULL, bh);
4809 if (!err)
4810 err = rc;
4811 ext4_clear_inode_state(inode, EXT4_STATE_NEW);
4812 if (set_large_file) {
4813 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
4814 err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
4815 if (err)
4816 goto out_brelse;
4817 ext4_update_dynamic_rev(sb);
4818 ext4_set_feature_large_file(sb);
4819 ext4_handle_sync(handle);
4820 err = ext4_handle_dirty_super(handle, sb);
4821 }
4822 ext4_update_inode_fsync_trans(handle, inode, need_datasync);
4823 out_brelse:
4824 brelse(bh);
4825 ext4_std_error(inode->i_sb, err);
4826 return err;
4827 }
4828
4829 /*
4830 * ext4_write_inode()
4831 *
4832 * We are called from a few places:
4833 *
4834 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
4835 * Here, there will be no transaction running. We wait for any running
4836 * transaction to commit.
4837 *
4838 * - Within flush work (sys_sync(), kupdate and such).
4839 * We wait on commit, if told to.
4840 *
4841 * - Within iput_final() -> write_inode_now()
4842 * We wait on commit, if told to.
4843 *
4844 * In all cases it is actually safe for us to return without doing anything,
4845 * because the inode has been copied into a raw inode buffer in
4846 * ext4_mark_inode_dirty(). This is a correctness thing for WB_SYNC_ALL
4847 * writeback.
4848 *
4849 * Note that we are absolutely dependent upon all inode dirtiers doing the
4850 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4851 * which we are interested.
4852 *
4853 * It would be a bug for them to not do this. The code:
4854 *
4855 * mark_inode_dirty(inode)
4856 * stuff();
4857 * inode->i_size = expr;
4858 *
4859 * is in error because write_inode() could occur while `stuff()' is running,
4860 * and the new i_size will be lost. Plus the inode will no longer be on the
4861 * superblock's dirty inode list.
4862 */
4863 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
4864 {
4865 int err;
4866
4867 if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
4868 return 0;
4869
4870 if (EXT4_SB(inode->i_sb)->s_journal) {
4871 if (ext4_journal_current_handle()) {
4872 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4873 dump_stack();
4874 return -EIO;
4875 }
4876
4877 /*
4878 * No need to force transaction in WB_SYNC_NONE mode. Also
4879 * ext4_sync_fs() will force the commit after everything is
4880 * written.
4881 */
4882 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
4883 return 0;
4884
4885 err = ext4_force_commit(inode->i_sb);
4886 } else {
4887 struct ext4_iloc iloc;
4888
4889 err = __ext4_get_inode_loc(inode, &iloc, 0);
4890 if (err)
4891 return err;
4892 /*
4893 * sync(2) will flush the whole buffer cache. No need to do
4894 * it here separately for each inode.
4895 */
4896 if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
4897 sync_dirty_buffer(iloc.bh);
4898 if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
4899 EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr,
4900 "IO error syncing inode");
4901 err = -EIO;
4902 }
4903 brelse(iloc.bh);
4904 }
4905 return err;
4906 }
4907
4908 /*
4909 * In data=journal mode ext4_journalled_invalidatepage() may fail to invalidate
4910 * buffers that are attached to a page stradding i_size and are undergoing
4911 * commit. In that case we have to wait for commit to finish and try again.
4912 */
4913 static void ext4_wait_for_tail_page_commit(struct inode *inode)
4914 {
4915 struct page *page;
4916 unsigned offset;
4917 journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
4918 tid_t commit_tid = 0;
4919 int ret;
4920
4921 offset = inode->i_size & (PAGE_SIZE - 1);
4922 /*
4923 * All buffers in the last page remain valid? Then there's nothing to
4924 * do. We do the check mainly to optimize the common PAGE_SIZE ==
4925 * blocksize case
4926 */
4927 if (offset > PAGE_SIZE - (1 << inode->i_blkbits))
4928 return;
4929 while (1) {
4930 page = find_lock_page(inode->i_mapping,
4931 inode->i_size >> PAGE_SHIFT);
4932 if (!page)
4933 return;
4934 ret = __ext4_journalled_invalidatepage(page, offset,
4935 PAGE_SIZE - offset);
4936 unlock_page(page);
4937 put_page(page);
4938 if (ret != -EBUSY)
4939 return;
4940 commit_tid = 0;
4941 read_lock(&journal->j_state_lock);
4942 if (journal->j_committing_transaction)
4943 commit_tid = journal->j_committing_transaction->t_tid;
4944 read_unlock(&journal->j_state_lock);
4945 if (commit_tid)
4946 jbd2_log_wait_commit(journal, commit_tid);
4947 }
4948 }
4949
4950 /*
4951 * ext4_setattr()
4952 *
4953 * Called from notify_change.
4954 *
4955 * We want to trap VFS attempts to truncate the file as soon as
4956 * possible. In particular, we want to make sure that when the VFS
4957 * shrinks i_size, we put the inode on the orphan list and modify
4958 * i_disksize immediately, so that during the subsequent flushing of
4959 * dirty pages and freeing of disk blocks, we can guarantee that any
4960 * commit will leave the blocks being flushed in an unused state on
4961 * disk. (On recovery, the inode will get truncated and the blocks will
4962 * be freed, so we have a strong guarantee that no future commit will
4963 * leave these blocks visible to the user.)
4964 *
4965 * Another thing we have to assure is that if we are in ordered mode
4966 * and inode is still attached to the committing transaction, we must
4967 * we start writeout of all the dirty pages which are being truncated.
4968 * This way we are sure that all the data written in the previous
4969 * transaction are already on disk (truncate waits for pages under
4970 * writeback).
4971 *
4972 * Called with inode->i_mutex down.
4973 */
4974 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4975 {
4976 struct inode *inode = d_inode(dentry);
4977 int error, rc = 0;
4978 int orphan = 0;
4979 const unsigned int ia_valid = attr->ia_valid;
4980
4981 error = inode_change_ok(inode, attr);
4982 if (error)
4983 return error;
4984
4985 if (is_quota_modification(inode, attr)) {
4986 error = dquot_initialize(inode);
4987 if (error)
4988 return error;
4989 }
4990 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
4991 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
4992 handle_t *handle;
4993
4994 /* (user+group)*(old+new) structure, inode write (sb,
4995 * inode block, ? - but truncate inode update has it) */
4996 handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
4997 (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
4998 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
4999 if (IS_ERR(handle)) {
5000 error = PTR_ERR(handle);
5001 goto err_out;
5002 }
5003 error = dquot_transfer(inode, attr);
5004 if (error) {
5005 ext4_journal_stop(handle);
5006 return error;
5007 }
5008 /* Update corresponding info in inode so that everything is in
5009 * one transaction */
5010 if (attr->ia_valid & ATTR_UID)
5011 inode->i_uid = attr->ia_uid;
5012 if (attr->ia_valid & ATTR_GID)
5013 inode->i_gid = attr->ia_gid;
5014 error = ext4_mark_inode_dirty(handle, inode);
5015 ext4_journal_stop(handle);
5016 }
5017
5018 if (attr->ia_valid & ATTR_SIZE) {
5019 handle_t *handle;
5020 loff_t oldsize = inode->i_size;
5021 int shrink = (attr->ia_size <= inode->i_size);
5022
5023 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5024 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5025
5026 if (attr->ia_size > sbi->s_bitmap_maxbytes)
5027 return -EFBIG;
5028 }
5029 if (!S_ISREG(inode->i_mode))
5030 return -EINVAL;
5031
5032 if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5033 inode_inc_iversion(inode);
5034
5035 if (ext4_should_order_data(inode) &&
5036 (attr->ia_size < inode->i_size)) {
5037 error = ext4_begin_ordered_truncate(inode,
5038 attr->ia_size);
5039 if (error)
5040 goto err_out;
5041 }
5042 if (attr->ia_size != inode->i_size) {
5043 handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5044 if (IS_ERR(handle)) {
5045 error = PTR_ERR(handle);
5046 goto err_out;
5047 }
5048 if (ext4_handle_valid(handle) && shrink) {
5049 error = ext4_orphan_add(handle, inode);
5050 orphan = 1;
5051 }
5052 /*
5053 * Update c/mtime on truncate up, ext4_truncate() will
5054 * update c/mtime in shrink case below
5055 */
5056 if (!shrink) {
5057 inode->i_mtime = ext4_current_time(inode);
5058 inode->i_ctime = inode->i_mtime;
5059 }
5060 down_write(&EXT4_I(inode)->i_data_sem);
5061 EXT4_I(inode)->i_disksize = attr->ia_size;
5062 rc = ext4_mark_inode_dirty(handle, inode);
5063 if (!error)
5064 error = rc;
5065 /*
5066 * We have to update i_size under i_data_sem together
5067 * with i_disksize to avoid races with writeback code
5068 * running ext4_wb_update_i_disksize().
5069 */
5070 if (!error)
5071 i_size_write(inode, attr->ia_size);
5072 up_write(&EXT4_I(inode)->i_data_sem);
5073 ext4_journal_stop(handle);
5074 if (error) {
5075 if (orphan)
5076 ext4_orphan_del(NULL, inode);
5077 goto err_out;
5078 }
5079 }
5080 if (!shrink)
5081 pagecache_isize_extended(inode, oldsize, inode->i_size);
5082
5083 /*
5084 * Blocks are going to be removed from the inode. Wait
5085 * for dio in flight. Temporarily disable
5086 * dioread_nolock to prevent livelock.
5087 */
5088 if (orphan) {
5089 if (!ext4_should_journal_data(inode)) {
5090 ext4_inode_block_unlocked_dio(inode);
5091 inode_dio_wait(inode);
5092 ext4_inode_resume_unlocked_dio(inode);
5093 } else
5094 ext4_wait_for_tail_page_commit(inode);
5095 }
5096 down_write(&EXT4_I(inode)->i_mmap_sem);
5097 /*
5098 * Truncate pagecache after we've waited for commit
5099 * in data=journal mode to make pages freeable.
5100 */
5101 truncate_pagecache(inode, inode->i_size);
5102 if (shrink)
5103 ext4_truncate(inode);
5104 up_write(&EXT4_I(inode)->i_mmap_sem);
5105 }
5106
5107 if (!rc) {
5108 setattr_copy(inode, attr);
5109 mark_inode_dirty(inode);
5110 }
5111
5112 /*
5113 * If the call to ext4_truncate failed to get a transaction handle at
5114 * all, we need to clean up the in-core orphan list manually.
5115 */
5116 if (orphan && inode->i_nlink)
5117 ext4_orphan_del(NULL, inode);
5118
5119 if (!rc && (ia_valid & ATTR_MODE))
5120 rc = posix_acl_chmod(inode, inode->i_mode);
5121
5122 err_out:
5123 ext4_std_error(inode->i_sb, error);
5124 if (!error)
5125 error = rc;
5126 return error;
5127 }
5128
5129 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
5130 struct kstat *stat)
5131 {
5132 struct inode *inode;
5133 unsigned long long delalloc_blocks;
5134
5135 inode = d_inode(dentry);
5136 generic_fillattr(inode, stat);
5137
5138 /*
5139 * If there is inline data in the inode, the inode will normally not
5140 * have data blocks allocated (it may have an external xattr block).
5141 * Report at least one sector for such files, so tools like tar, rsync,
5142 * others doen't incorrectly think the file is completely sparse.
5143 */
5144 if (unlikely(ext4_has_inline_data(inode)))
5145 stat->blocks += (stat->size + 511) >> 9;
5146
5147 /*
5148 * We can't update i_blocks if the block allocation is delayed
5149 * otherwise in the case of system crash before the real block
5150 * allocation is done, we will have i_blocks inconsistent with
5151 * on-disk file blocks.
5152 * We always keep i_blocks updated together with real
5153 * allocation. But to not confuse with user, stat
5154 * will return the blocks that include the delayed allocation
5155 * blocks for this file.
5156 */
5157 delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5158 EXT4_I(inode)->i_reserved_data_blocks);
5159 stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5160 return 0;
5161 }
5162
5163 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5164 int pextents)
5165 {
5166 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5167 return ext4_ind_trans_blocks(inode, lblocks);
5168 return ext4_ext_index_trans_blocks(inode, pextents);
5169 }
5170
5171 /*
5172 * Account for index blocks, block groups bitmaps and block group
5173 * descriptor blocks if modify datablocks and index blocks
5174 * worse case, the indexs blocks spread over different block groups
5175 *
5176 * If datablocks are discontiguous, they are possible to spread over
5177 * different block groups too. If they are contiguous, with flexbg,
5178 * they could still across block group boundary.
5179 *
5180 * Also account for superblock, inode, quota and xattr blocks
5181 */
5182 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5183 int pextents)
5184 {
5185 ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5186 int gdpblocks;
5187 int idxblocks;
5188 int ret = 0;
5189
5190 /*
5191 * How many index blocks need to touch to map @lblocks logical blocks
5192 * to @pextents physical extents?
5193 */
5194 idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5195
5196 ret = idxblocks;
5197
5198 /*
5199 * Now let's see how many group bitmaps and group descriptors need
5200 * to account
5201 */
5202 groups = idxblocks + pextents;
5203 gdpblocks = groups;
5204 if (groups > ngroups)
5205 groups = ngroups;
5206 if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5207 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5208
5209 /* bitmaps and block group descriptor blocks */
5210 ret += groups + gdpblocks;
5211
5212 /* Blocks for super block, inode, quota and xattr blocks */
5213 ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5214
5215 return ret;
5216 }
5217
5218 /*
5219 * Calculate the total number of credits to reserve to fit
5220 * the modification of a single pages into a single transaction,
5221 * which may include multiple chunks of block allocations.
5222 *
5223 * This could be called via ext4_write_begin()
5224 *
5225 * We need to consider the worse case, when
5226 * one new block per extent.
5227 */
5228 int ext4_writepage_trans_blocks(struct inode *inode)
5229 {
5230 int bpp = ext4_journal_blocks_per_page(inode);
5231 int ret;
5232
5233 ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5234
5235 /* Account for data blocks for journalled mode */
5236 if (ext4_should_journal_data(inode))
5237 ret += bpp;
5238 return ret;
5239 }
5240
5241 /*
5242 * Calculate the journal credits for a chunk of data modification.
5243 *
5244 * This is called from DIO, fallocate or whoever calling
5245 * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5246 *
5247 * journal buffers for data blocks are not included here, as DIO
5248 * and fallocate do no need to journal data buffers.
5249 */
5250 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5251 {
5252 return ext4_meta_trans_blocks(inode, nrblocks, 1);
5253 }
5254
5255 /*
5256 * The caller must have previously called ext4_reserve_inode_write().
5257 * Give this, we know that the caller already has write access to iloc->bh.
5258 */
5259 int ext4_mark_iloc_dirty(handle_t *handle,
5260 struct inode *inode, struct ext4_iloc *iloc)
5261 {
5262 int err = 0;
5263
5264 if (IS_I_VERSION(inode))
5265 inode_inc_iversion(inode);
5266
5267 /* the do_update_inode consumes one bh->b_count */
5268 get_bh(iloc->bh);
5269
5270 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5271 err = ext4_do_update_inode(handle, inode, iloc);
5272 put_bh(iloc->bh);
5273 return err;
5274 }
5275
5276 /*
5277 * On success, We end up with an outstanding reference count against
5278 * iloc->bh. This _must_ be cleaned up later.
5279 */
5280
5281 int
5282 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5283 struct ext4_iloc *iloc)
5284 {
5285 int err;
5286
5287 err = ext4_get_inode_loc(inode, iloc);
5288 if (!err) {
5289 BUFFER_TRACE(iloc->bh, "get_write_access");
5290 err = ext4_journal_get_write_access(handle, iloc->bh);
5291 if (err) {
5292 brelse(iloc->bh);
5293 iloc->bh = NULL;
5294 }
5295 }
5296 ext4_std_error(inode->i_sb, err);
5297 return err;
5298 }
5299
5300 /*
5301 * Expand an inode by new_extra_isize bytes.
5302 * Returns 0 on success or negative error number on failure.
5303 */
5304 static int ext4_expand_extra_isize(struct inode *inode,
5305 unsigned int new_extra_isize,
5306 struct ext4_iloc iloc,
5307 handle_t *handle)
5308 {
5309 struct ext4_inode *raw_inode;
5310 struct ext4_xattr_ibody_header *header;
5311
5312 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5313 return 0;
5314
5315 raw_inode = ext4_raw_inode(&iloc);
5316
5317 header = IHDR(inode, raw_inode);
5318
5319 /* No extended attributes present */
5320 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5321 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5322 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5323 new_extra_isize);
5324 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5325 return 0;
5326 }
5327
5328 /* try to expand with EAs present */
5329 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5330 raw_inode, handle);
5331 }
5332
5333 /*
5334 * What we do here is to mark the in-core inode as clean with respect to inode
5335 * dirtiness (it may still be data-dirty).
5336 * This means that the in-core inode may be reaped by prune_icache
5337 * without having to perform any I/O. This is a very good thing,
5338 * because *any* task may call prune_icache - even ones which
5339 * have a transaction open against a different journal.
5340 *
5341 * Is this cheating? Not really. Sure, we haven't written the
5342 * inode out, but prune_icache isn't a user-visible syncing function.
5343 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5344 * we start and wait on commits.
5345 */
5346 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5347 {
5348 struct ext4_iloc iloc;
5349 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5350 static unsigned int mnt_count;
5351 int err, ret;
5352
5353 might_sleep();
5354 trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5355 err = ext4_reserve_inode_write(handle, inode, &iloc);
5356 if (err)
5357 return err;
5358 if (ext4_handle_valid(handle) &&
5359 EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5360 !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5361 /*
5362 * We need extra buffer credits since we may write into EA block
5363 * with this same handle. If journal_extend fails, then it will
5364 * only result in a minor loss of functionality for that inode.
5365 * If this is felt to be critical, then e2fsck should be run to
5366 * force a large enough s_min_extra_isize.
5367 */
5368 if ((jbd2_journal_extend(handle,
5369 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5370 ret = ext4_expand_extra_isize(inode,
5371 sbi->s_want_extra_isize,
5372 iloc, handle);
5373 if (ret) {
5374 ext4_set_inode_state(inode,
5375 EXT4_STATE_NO_EXPAND);
5376 if (mnt_count !=
5377 le16_to_cpu(sbi->s_es->s_mnt_count)) {
5378 ext4_warning(inode->i_sb,
5379 "Unable to expand inode %lu. Delete"
5380 " some EAs or run e2fsck.",
5381 inode->i_ino);
5382 mnt_count =
5383 le16_to_cpu(sbi->s_es->s_mnt_count);
5384 }
5385 }
5386 }
5387 }
5388 return ext4_mark_iloc_dirty(handle, inode, &iloc);
5389 }
5390
5391 /*
5392 * ext4_dirty_inode() is called from __mark_inode_dirty()
5393 *
5394 * We're really interested in the case where a file is being extended.
5395 * i_size has been changed by generic_commit_write() and we thus need
5396 * to include the updated inode in the current transaction.
5397 *
5398 * Also, dquot_alloc_block() will always dirty the inode when blocks
5399 * are allocated to the file.
5400 *
5401 * If the inode is marked synchronous, we don't honour that here - doing
5402 * so would cause a commit on atime updates, which we don't bother doing.
5403 * We handle synchronous inodes at the highest possible level.
5404 *
5405 * If only the I_DIRTY_TIME flag is set, we can skip everything. If
5406 * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
5407 * to copy into the on-disk inode structure are the timestamp files.
5408 */
5409 void ext4_dirty_inode(struct inode *inode, int flags)
5410 {
5411 handle_t *handle;
5412
5413 if (flags == I_DIRTY_TIME)
5414 return;
5415 handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5416 if (IS_ERR(handle))
5417 goto out;
5418
5419 ext4_mark_inode_dirty(handle, inode);
5420
5421 ext4_journal_stop(handle);
5422 out:
5423 return;
5424 }
5425
5426 #if 0
5427 /*
5428 * Bind an inode's backing buffer_head into this transaction, to prevent
5429 * it from being flushed to disk early. Unlike
5430 * ext4_reserve_inode_write, this leaves behind no bh reference and
5431 * returns no iloc structure, so the caller needs to repeat the iloc
5432 * lookup to mark the inode dirty later.
5433 */
5434 static int ext4_pin_inode(handle_t *handle, struct inode *inode)
5435 {
5436 struct ext4_iloc iloc;
5437
5438 int err = 0;
5439 if (handle) {
5440 err = ext4_get_inode_loc(inode, &iloc);
5441 if (!err) {
5442 BUFFER_TRACE(iloc.bh, "get_write_access");
5443 err = jbd2_journal_get_write_access(handle, iloc.bh);
5444 if (!err)
5445 err = ext4_handle_dirty_metadata(handle,
5446 NULL,
5447 iloc.bh);
5448 brelse(iloc.bh);
5449 }
5450 }
5451 ext4_std_error(inode->i_sb, err);
5452 return err;
5453 }
5454 #endif
5455
5456 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5457 {
5458 journal_t *journal;
5459 handle_t *handle;
5460 int err;
5461
5462 /*
5463 * We have to be very careful here: changing a data block's
5464 * journaling status dynamically is dangerous. If we write a
5465 * data block to the journal, change the status and then delete
5466 * that block, we risk forgetting to revoke the old log record
5467 * from the journal and so a subsequent replay can corrupt data.
5468 * So, first we make sure that the journal is empty and that
5469 * nobody is changing anything.
5470 */
5471
5472 journal = EXT4_JOURNAL(inode);
5473 if (!journal)
5474 return 0;
5475 if (is_journal_aborted(journal))
5476 return -EROFS;
5477 /* We have to allocate physical blocks for delalloc blocks
5478 * before flushing journal. otherwise delalloc blocks can not
5479 * be allocated any more. even more truncate on delalloc blocks
5480 * could trigger BUG by flushing delalloc blocks in journal.
5481 * There is no delalloc block in non-journal data mode.
5482 */
5483 if (val && test_opt(inode->i_sb, DELALLOC)) {
5484 err = ext4_alloc_da_blocks(inode);
5485 if (err < 0)
5486 return err;
5487 }
5488
5489 /* Wait for all existing dio workers */
5490 ext4_inode_block_unlocked_dio(inode);
5491 inode_dio_wait(inode);
5492
5493 jbd2_journal_lock_updates(journal);
5494
5495 /*
5496 * OK, there are no updates running now, and all cached data is
5497 * synced to disk. We are now in a completely consistent state
5498 * which doesn't have anything in the journal, and we know that
5499 * no filesystem updates are running, so it is safe to modify
5500 * the inode's in-core data-journaling state flag now.
5501 */
5502
5503 if (val)
5504 ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5505 else {
5506 err = jbd2_journal_flush(journal);
5507 if (err < 0) {
5508 jbd2_journal_unlock_updates(journal);
5509 ext4_inode_resume_unlocked_dio(inode);
5510 return err;
5511 }
5512 ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
5513 }
5514 ext4_set_aops(inode);
5515
5516 jbd2_journal_unlock_updates(journal);
5517 ext4_inode_resume_unlocked_dio(inode);
5518
5519 /* Finally we can mark the inode as dirty. */
5520
5521 handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
5522 if (IS_ERR(handle))
5523 return PTR_ERR(handle);
5524
5525 err = ext4_mark_inode_dirty(handle, inode);
5526 ext4_handle_sync(handle);
5527 ext4_journal_stop(handle);
5528 ext4_std_error(inode->i_sb, err);
5529
5530 return err;
5531 }
5532
5533 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
5534 {
5535 return !buffer_mapped(bh);
5536 }
5537
5538 int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
5539 {
5540 struct page *page = vmf->page;
5541 loff_t size;
5542 unsigned long len;
5543 int ret;
5544 struct file *file = vma->vm_file;
5545 struct inode *inode = file_inode(file);
5546 struct address_space *mapping = inode->i_mapping;
5547 handle_t *handle;
5548 get_block_t *get_block;
5549 int retries = 0;
5550
5551 sb_start_pagefault(inode->i_sb);
5552 file_update_time(vma->vm_file);
5553
5554 down_read(&EXT4_I(inode)->i_mmap_sem);
5555 /* Delalloc case is easy... */
5556 if (test_opt(inode->i_sb, DELALLOC) &&
5557 !ext4_should_journal_data(inode) &&
5558 !ext4_nonda_switch(inode->i_sb)) {
5559 do {
5560 ret = block_page_mkwrite(vma, vmf,
5561 ext4_da_get_block_prep);
5562 } while (ret == -ENOSPC &&
5563 ext4_should_retry_alloc(inode->i_sb, &retries));
5564 goto out_ret;
5565 }
5566
5567 lock_page(page);
5568 size = i_size_read(inode);
5569 /* Page got truncated from under us? */
5570 if (page->mapping != mapping || page_offset(page) > size) {
5571 unlock_page(page);
5572 ret = VM_FAULT_NOPAGE;
5573 goto out;
5574 }
5575
5576 if (page->index == size >> PAGE_SHIFT)
5577 len = size & ~PAGE_MASK;
5578 else
5579 len = PAGE_SIZE;
5580 /*
5581 * Return if we have all the buffers mapped. This avoids the need to do
5582 * journal_start/journal_stop which can block and take a long time
5583 */
5584 if (page_has_buffers(page)) {
5585 if (!ext4_walk_page_buffers(NULL, page_buffers(page),
5586 0, len, NULL,
5587 ext4_bh_unmapped)) {
5588 /* Wait so that we don't change page under IO */
5589 wait_for_stable_page(page);
5590 ret = VM_FAULT_LOCKED;
5591 goto out;
5592 }
5593 }
5594 unlock_page(page);
5595 /* OK, we need to fill the hole... */
5596 if (ext4_should_dioread_nolock(inode))
5597 get_block = ext4_get_block_unwritten;
5598 else
5599 get_block = ext4_get_block;
5600 retry_alloc:
5601 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
5602 ext4_writepage_trans_blocks(inode));
5603 if (IS_ERR(handle)) {
5604 ret = VM_FAULT_SIGBUS;
5605 goto out;
5606 }
5607 ret = block_page_mkwrite(vma, vmf, get_block);
5608 if (!ret && ext4_should_journal_data(inode)) {
5609 if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
5610 PAGE_SIZE, NULL, do_journal_get_write_access)) {
5611 unlock_page(page);
5612 ret = VM_FAULT_SIGBUS;
5613 ext4_journal_stop(handle);
5614 goto out;
5615 }
5616 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
5617 }
5618 ext4_journal_stop(handle);
5619 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
5620 goto retry_alloc;
5621 out_ret:
5622 ret = block_page_mkwrite_return(ret);
5623 out:
5624 up_read(&EXT4_I(inode)->i_mmap_sem);
5625 sb_end_pagefault(inode->i_sb);
5626 return ret;
5627 }
5628
5629 int ext4_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
5630 {
5631 struct inode *inode = file_inode(vma->vm_file);
5632 int err;
5633
5634 down_read(&EXT4_I(inode)->i_mmap_sem);
5635 err = filemap_fault(vma, vmf);
5636 up_read(&EXT4_I(inode)->i_mmap_sem);
5637
5638 return err;
5639 }
5640
5641 /*
5642 * Find the first extent at or after @lblk in an inode that is not a hole.
5643 * Search for @map_len blocks at most. The extent is returned in @result.
5644 *
5645 * The function returns 1 if we found an extent. The function returns 0 in
5646 * case there is no extent at or after @lblk and in that case also sets
5647 * @result->es_len to 0. In case of error, the error code is returned.
5648 */
5649 int ext4_get_next_extent(struct inode *inode, ext4_lblk_t lblk,
5650 unsigned int map_len, struct extent_status *result)
5651 {
5652 struct ext4_map_blocks map;
5653 struct extent_status es = {};
5654 int ret;
5655
5656 map.m_lblk = lblk;
5657 map.m_len = map_len;
5658
5659 /*
5660 * For non-extent based files this loop may iterate several times since
5661 * we do not determine full hole size.
5662 */
5663 while (map.m_len > 0) {
5664 ret = ext4_map_blocks(NULL, inode, &map, 0);
5665 if (ret < 0)
5666 return ret;
5667 /* There's extent covering m_lblk? Just return it. */
5668 if (ret > 0) {
5669 int status;
5670
5671 ext4_es_store_pblock(result, map.m_pblk);
5672 result->es_lblk = map.m_lblk;
5673 result->es_len = map.m_len;
5674 if (map.m_flags & EXT4_MAP_UNWRITTEN)
5675 status = EXTENT_STATUS_UNWRITTEN;
5676 else
5677 status = EXTENT_STATUS_WRITTEN;
5678 ext4_es_store_status(result, status);
5679 return 1;
5680 }
5681 ext4_es_find_delayed_extent_range(inode, map.m_lblk,
5682 map.m_lblk + map.m_len - 1,
5683 &es);
5684 /* Is delalloc data before next block in extent tree? */
5685 if (es.es_len && es.es_lblk < map.m_lblk + map.m_len) {
5686 ext4_lblk_t offset = 0;
5687
5688 if (es.es_lblk < lblk)
5689 offset = lblk - es.es_lblk;
5690 result->es_lblk = es.es_lblk + offset;
5691 ext4_es_store_pblock(result,
5692 ext4_es_pblock(&es) + offset);
5693 result->es_len = es.es_len - offset;
5694 ext4_es_store_status(result, ext4_es_status(&es));
5695
5696 return 1;
5697 }
5698 /* There's a hole at m_lblk, advance us after it */
5699 map.m_lblk += map.m_len;
5700 map_len -= map.m_len;
5701 map.m_len = map_len;
5702 cond_resched();
5703 }
5704 result->es_len = 0;
5705 return 0;
5706 }
5707
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