inode.c source code [Linux/fs/ext4/inode.c]

1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* linux/fs/ext4/inode.c
4	*
5	* Copyright (C) 1992, 1993, 1994, 1995
6	* Remy Card (card@masi.ibp.fr)
7	* Laboratoire MASI - Institut Blaise Pascal
8	* Universite Pierre et Marie Curie (Paris VI)
9	*
10	* from
11	*
12	* linux/fs/minix/inode.c
13	*
14	* Copyright (C) 1991, 1992 Linus Torvalds
15	*
16	* 64-bit file support on 64-bit platforms by Jakub Jelinek
17	* (jj@sunsite.ms.mff.cuni.cz)
18	*
19	* Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
20	*/
21
22	#include <linux/fs.h>
23	#include <linux/mount.h>
24	#include <linux/time.h>
25	#include <linux/highuid.h>
26	#include <linux/pagemap.h>
27	#include <linux/dax.h>
28	#include <linux/quotaops.h>
29	#include <linux/string.h>
30	#include <linux/buffer_head.h>
31	#include <linux/writeback.h>
32	#include <linux/pagevec.h>
33	#include <linux/mpage.h>
34	#include <linux/rmap.h>
35	#include <linux/namei.h>
36	#include <linux/uio.h>
37	#include <linux/bio.h>
38	#include <linux/workqueue.h>
39	#include <linux/kernel.h>
40	#include <linux/printk.h>
41	#include <linux/slab.h>
42	#include <linux/bitops.h>
43	#include <linux/iomap.h>
44	#include <linux/iversion.h>
45
46	#include "ext4_jbd2.h"
47	#include "xattr.h"
48	#include "acl.h"
49	#include "truncate.h"
50
51	#include <trace/events/ext4.h>
52
53	static void ext4_journalled_zero_new_buffers(handle_t *handle,
54	struct inode *inode,
55	struct folio *folio,
56	unsigned from, unsigned to);
57
58	static __u32 ext4_inode_csum(struct inode inode, struct* ext4_inode *raw,
59	struct ext4_inode_info *ei)
60	{
61	__u32 csum;
62	__u16 dummy_csum = `0`;
63	int offset = offsetof(struct ext4_inode, i_checksum_lo);
64	unsigned int csum_size = sizeof(dummy_csum);
65
66	csum = ext4_chksum(crc: ei->i_csum_seed, address: (__u8 *)raw, length: offset);
67	csum = ext4_chksum(crc: csum, address: (__u8 *)&dummy_csum, length: csum_size);
68	offset += csum_size;
69	csum = ext4_chksum(crc: csum, address: (__u8 *)raw + offset,
70	EXT4_GOOD_OLD_INODE_SIZE - offset);
71
72	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
73	offset = offsetof(struct ext4_inode, i_checksum_hi);
74	csum = ext4_chksum(crc: csum, address: (__u8 *)raw + EXT4_GOOD_OLD_INODE_SIZE,
75	length: offset - EXT4_GOOD_OLD_INODE_SIZE);
76	if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
77	csum = ext4_chksum(crc: csum, address: (__u8 *)&dummy_csum,
78	length: csum_size);
79	offset += csum_size;
80	}
81	csum = ext4_chksum(crc: csum, address: (__u8 *)raw + offset,
82	EXT4_INODE_SIZE(inode->i_sb) - offset);
83	}
84
85	return csum;
86	}
87
88	static int ext4_inode_csum_verify(struct inode inode, struct* ext4_inode *raw,
89	struct ext4_inode_info *ei)
90	{
91	__u32 provided, calculated;
92
93	if (EXT4_SB(sb: inode->i_sb)->s_es->s_creator_os !=
94	cpu_to_le32(EXT4_OS_LINUX) \|\|
95	!ext4_has_feature_metadata_csum(sb: inode->i_sb))
96	return `1`;
97
98	provided = le16_to_cpu(raw->i_checksum_lo);
99	calculated = ext4_inode_csum(inode, raw, ei);
100	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
101	EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
102	provided \|= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << `16`;
103	else
104	calculated &= `0xFFFF`;
105
106	return provided == calculated;
107	}
108
109	void ext4_inode_csum_set(struct inode inode, struct* ext4_inode *raw,
110	struct ext4_inode_info *ei)
111	{
112	__u32 csum;
113
114	if (EXT4_SB(sb: inode->i_sb)->s_es->s_creator_os !=
115	cpu_to_le32(EXT4_OS_LINUX) \|\|
116	!ext4_has_feature_metadata_csum(sb: inode->i_sb))
117	return;
118
119	csum = ext4_inode_csum(inode, raw, ei);
120	raw->i_checksum_lo = cpu_to_le16(csum & `0xFFFF`);
121	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
122	EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
123	raw->i_checksum_hi = cpu_to_le16(csum >> `16`);
124	}
125
126	static inline int ext4_begin_ordered_truncate(struct inode *inode,
127	loff_t new_size)
128	{
129	trace_ext4_begin_ordered_truncate(inode, new_size);
130	/*
131	* If jinode is zero, then we never opened the file for
132	* writing, so there's no need to call
133	* jbd2_journal_begin_ordered_truncate() since there's no
134	* outstanding writes we need to flush.
135	*/
136	if (!EXT4_I(inode)->jinode)
137	return `0`;
138	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
139	EXT4_I(inode)->jinode,
140	new_size);
141	}
142
143	/*
144	* Test whether an inode is a fast symlink.
145	* A fast symlink has its symlink data stored in ext4_inode_info->i_data.
146	*/
147	int ext4_inode_is_fast_symlink(struct inode *inode)
148	{
149	if (!ext4_has_feature_ea_inode(sb: inode->i_sb)) {
150	int ea_blocks = EXT4_I(inode)->i_file_acl ?
151	EXT4_CLUSTER_SIZE(inode->i_sb) >> `9` : `0`;
152
153	if (ext4_has_inline_data(inode))
154	return `0`;
155
156	return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == `0`);
157	}
158	return S_ISLNK(inode->i_mode) && inode->i_size &&
159	(inode->i_size < EXT4_N_BLOCKS * `4`);
160	}
161
162	/*
163	* Called at the last iput() if i_nlink is zero.
164	*/
165	void ext4_evict_inode(struct inode *inode)
166	{
167	handle_t *handle;
168	int err;
169	/*
170	* Credits for final inode cleanup and freeing:
171	* sb + inode (ext4_orphan_del()), block bitmap, group descriptor
172	* (xattr block freeing), bitmap, group descriptor (inode freeing)
173	*/
174	int extra_credits = `6`;
175	struct ext4_xattr_inode_array *ea_inode_array = NULL;
176	bool freeze_protected = false;
177
178	trace_ext4_evict_inode(inode);
179
180	dax_break_layout_final(inode);
181
182	if (EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)
183	ext4_evict_ea_inode(inode);
184	if (inode->i_nlink) {
185	truncate_inode_pages_final(&inode->i_data);
186
187	goto no_delete;
188	}
189
190	if (is_bad_inode(inode))
191	goto no_delete;
192	dquot_initialize(inode);
193
194	if (ext4_should_order_data(inode))
195	ext4_begin_ordered_truncate(inode, new_size: `0`);
196	truncate_inode_pages_final(&inode->i_data);
197
198	/*
199	* For inodes with journalled data, transaction commit could have
200	* dirtied the inode. And for inodes with dioread_nolock, unwritten
201	* extents converting worker could merge extents and also have dirtied
202	* the inode. Flush worker is ignoring it because of I_FREEING flag but
203	* we still need to remove the inode from the writeback lists.
204	*/
205	if (!list_empty_careful(head: &inode->i_io_list))
206	inode_io_list_del(inode);
207
208	/*
209	* Protect us against freezing - iput() caller didn't have to have any
210	* protection against it. When we are in a running transaction though,
211	* we are already protected against freezing and we cannot grab further
212	* protection due to lock ordering constraints.
213	*/
214	if (!ext4_journal_current_handle()) {
215	sb_start_intwrite(sb: inode->i_sb);
216	freeze_protected = true;
217	}
218
219	if (!IS_NOQUOTA(inode))
220	extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
221
222	/*
223	* Block bitmap, group descriptor, and inode are accounted in both
224	* ext4_blocks_for_truncate() and extra_credits. So subtract 3.
225	*/
226	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
227	ext4_blocks_for_truncate(inode) + extra_credits - `3`);
228	if (IS_ERR(ptr: handle)) {
229	ext4_std_error(inode->i_sb, PTR_ERR(handle));
230	/*
231	* If we're going to skip the normal cleanup, we still need to
232	* make sure that the in-core orphan linked list is properly
233	* cleaned up.
234	*/
235	ext4_orphan_del(NULL, inode);
236	if (freeze_protected)
237	sb_end_intwrite(sb: inode->i_sb);
238	goto no_delete;
239	}
240
241	if (IS_SYNC(inode))
242	ext4_handle_sync(handle);
243
244	/*
245	* Set inode->i_size to 0 before calling ext4_truncate(). We need
246	* special handling of symlinks here because i_size is used to
247	* determine whether ext4_inode_info->i_data contains symlink data or
248	* block mappings. Setting i_size to 0 will remove its fast symlink
249	* status. Erase i_data so that it becomes a valid empty block map.
250	*/
251	if (ext4_inode_is_fast_symlink(inode))
252	memset(EXT4_I(inode)->i_data, c: `0`, n: sizeof(EXT4_I(inode)->i_data));
253	inode->i_size = `0`;
254	err = ext4_mark_inode_dirty(handle, inode);
255	if (err) {
256	ext4_warning(inode->i_sb,
257	"couldn't mark inode dirty (err %d)", err);
258	goto stop_handle;
259	}
260	if (inode->i_blocks) {
261	err = ext4_truncate(inode);
262	if (err) {
263	ext4_error_err(inode->i_sb, -err,
264	"couldn't truncate inode %lu (err %d)",
265	inode->i_ino, err);
266	goto stop_handle;
267	}
268	}
269
270	/ Remove xattr references. /
271	err = ext4_xattr_delete_inode(handle, inode, array: &ea_inode_array,
272	extra_credits);
273	if (err) {
274	ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
275	stop_handle:
276	ext4_journal_stop(handle);
277	ext4_orphan_del(NULL, inode);
278	if (freeze_protected)
279	sb_end_intwrite(sb: inode->i_sb);
280	ext4_xattr_inode_array_free(array: ea_inode_array);
281	goto no_delete;
282	}
283
284	/*
285	* Kill off the orphan record which ext4_truncate created.
286	* AKPM: I think this can be inside the above `if'.
287	* Note that ext4_orphan_del() has to be able to cope with the
288	* deletion of a non-existent orphan - this is because we don't
289	* know if ext4_truncate() actually created an orphan record.
290	* (Well, we could do this if we need to, but heck - it works)
291	*/
292	ext4_orphan_del(handle, inode);
293	EXT4_I(inode)->i_dtime = (__u32)ktime_get_real_seconds();
294
295	/*
296	* One subtle ordering requirement: if anything has gone wrong
297	* (transaction abort, IO errors, whatever), then we can still
298	* do these next steps (the fs will already have been marked as
299	* having errors), but we can't free the inode if the mark_dirty
300	* fails.
301	*/
302	if (ext4_mark_inode_dirty(handle, inode))
303	/ If that failed, just do the required in-core inode clear. /
304	ext4_clear_inode(inode);
305	else
306	ext4_free_inode(handle, inode);
307	ext4_journal_stop(handle);
308	if (freeze_protected)
309	sb_end_intwrite(sb: inode->i_sb);
310	ext4_xattr_inode_array_free(array: ea_inode_array);
311	return;
312	no_delete:
313	/*
314	* Check out some where else accidentally dirty the evicting inode,
315	* which may probably cause inode use-after-free issues later.
316	*/
317	WARN_ON_ONCE(!list_empty_careful(&inode->i_io_list));
318
319	if (!list_empty(head: &EXT4_I(inode)->i_fc_list))
320	ext4_fc_mark_ineligible(sb: inode->i_sb, reason: EXT4_FC_REASON_NOMEM, NULL);
321	ext4_clear_inode(inode); / We must guarantee clearing of inode... /
322	}
323
324	#ifdef CONFIG_QUOTA
325	qsize_t ext4_get_reserved_space(struct* inode *inode)
326	{
327	return &EXT4_I(inode)->i_reserved_quota;
328	}
329	#endif
330
331	/*
332	* Called with i_data_sem down, which is important since we can call
333	* ext4_discard_preallocations() from here.
334	*/
335	void ext4_da_update_reserve_space(struct inode *inode,
336	int used, int quota_claim)
337	{
338	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
339	struct ext4_inode_info *ei = EXT4_I(inode);
340
341	spin_lock(lock: &ei->i_block_reservation_lock);
342	trace_ext4_da_update_reserve_space(inode, used_blocks: used, quota_claim);
343	if (unlikely(used > ei->i_reserved_data_blocks)) {
344	ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
345	"with only %d reserved data blocks",
346	__func__, inode->i_ino, used,
347	ei->i_reserved_data_blocks);
348	WARN_ON(`1`);
349	used = ei->i_reserved_data_blocks;
350	}
351
352	/ Update per-inode reservations /
353	ei->i_reserved_data_blocks -= used;
354	percpu_counter_sub(fbc: &sbi->s_dirtyclusters_counter, amount: used);
355
356	spin_unlock(lock: &ei->i_block_reservation_lock);
357
358	/ Update quota subsystem for data blocks /
359	if (quota_claim)
360	dquot_claim_block(inode, EXT4_C2B(sbi, used));
361	else {
362	/*
363	* We did fallocate with an offset that is already delayed
364	* allocated. So on delayed allocated writeback we should
365	* not re-claim the quota for fallocated blocks.
366	*/
367	dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
368	}
369
370	/*
371	* If we have done all the pending block allocations and if
372	* there aren't any writers on the inode, we can discard the
373	* inode's preallocations.
374	*/
375	if ((ei->i_reserved_data_blocks == `0`) &&
376	!inode_is_open_for_write(inode))
377	ext4_discard_preallocations(inode);
378	}
379
380	static int __check_block_validity(struct inode inode, const* char *func,
381	unsigned int line,
382	struct ext4_map_blocks *map)
383	{
384	journal_t *journal = EXT4_SB(sb: inode->i_sb)->s_journal;
385
386	if (journal && inode == journal->j_inode)
387	return `0`;
388
389	if (!ext4_inode_block_valid(inode, start_blk: map->m_pblk, count: map->m_len)) {
390	ext4_error_inode(inode, func, line, map->m_pblk,
391	"lblock %lu mapped to illegal pblock %llu "
392	"(length %d)", (unsigned long) map->m_lblk,
393	map->m_pblk, map->m_len);
394	return -EFSCORRUPTED;
395	}
396	return `0`;
397	}
398
399	int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
400	ext4_lblk_t len)
401	{
402	int ret;
403
404	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
405	return fscrypt_zeroout_range(inode, lblk, pblk, len);
406
407	ret = sb_issue_zeroout(sb: inode->i_sb, block: pblk, nr_blocks: len, GFP_NOFS);
408	if (ret > `0`)
409	ret = `0`;
410
411	return ret;
412	}
413
414	/*
415	* For generic regular files, when updating the extent tree, Ext4 should
416	* hold the i_rwsem and invalidate_lock exclusively. This ensures
417	* exclusion against concurrent page faults, as well as reads and writes.
418	*/
419	#ifdef CONFIG_EXT4_DEBUG
420	void ext4_check_map_extents_env(struct inode *inode)
421	{
422	if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
423	return;
424
425	if (!S_ISREG(inode->i_mode) \|\|
426	IS_NOQUOTA(inode) \|\| IS_VERITY(inode) \|\|
427	is_special_ino(inode->i_sb, inode->i_ino) \|\|
428	(inode->i_state & (I_FREEING \| I_WILL_FREE \| I_NEW)) \|\|
429	ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE) \|\|
430	ext4_verity_in_progress(inode))
431	return;
432
433	WARN_ON_ONCE(!inode_is_locked(inode) &&
434	!rwsem_is_locked(&inode->i_mapping->invalidate_lock));
435	}
436	#else
437	void ext4_check_map_extents_env(struct inode *inode) {}
438	#endif
439
440	#define check_block_validity(inode, map) \
441	__check_block_validity((inode), __func__, __LINE__, (map))
442
443	#ifdef ES_AGGRESSIVE_TEST
444	static void ext4_map_blocks_es_recheck(handle_t *handle,
445	struct inode *inode,
446	struct ext4_map_blocks *es_map,
447	struct ext4_map_blocks *map,
448	int flags)
449	{
450	int retval;
451
452	map->m_flags = `0`;
453	/*
454	* There is a race window that the result is not the same.
455	* e.g. xfstests #223 when dioread_nolock enables. The reason
456	* is that we lookup a block mapping in extent status tree with
457	* out taking i_data_sem. So at the time the unwritten extent
458	* could be converted.
459	*/
460	down_read(&EXT4_I(inode)->i_data_sem);
461	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
462	retval = ext4_ext_map_blocks(handle, inode, map, `0`);
463	} else {
464	retval = ext4_ind_map_blocks(handle, inode, map, `0`);
465	}
466	up_read((&EXT4_I(inode)->i_data_sem));
467
468	/*
469	* We don't check m_len because extent will be collpased in status
470	* tree. So the m_len might not equal.
471	*/
472	if (es_map->m_lblk != map->m_lblk \|\|
473	es_map->m_flags != map->m_flags \|\|
474	es_map->m_pblk != map->m_pblk) {
475	printk("ES cache assertion failed for inode: %lu "
476	"es_cached ex [%d/%d/%llu/%x] != "
477	"found ex [%d/%d/%llu/%x] retval %d flags %x\n",
478	inode->i_ino, es_map->m_lblk, es_map->m_len,
479	es_map->m_pblk, es_map->m_flags, map->m_lblk,
480	map->m_len, map->m_pblk, map->m_flags,
481	retval, flags);
482	}
483	}
484	#endif /* ES_AGGRESSIVE_TEST */
485
486	static int ext4_map_query_blocks_next_in_leaf(handle_t *handle,
487	struct inode inode, struct* ext4_map_blocks *map,
488	unsigned int orig_mlen)
489	{
490	struct ext4_map_blocks map2;
491	unsigned int status, status2;
492	int retval;
493
494	status = map->m_flags & EXT4_MAP_UNWRITTEN ?
495	EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
496
497	WARN_ON_ONCE(!(map->m_flags & EXT4_MAP_QUERY_LAST_IN_LEAF));
498	WARN_ON_ONCE(orig_mlen <= map->m_len);
499
500	/ Prepare map2 for lookup in next leaf block /
501	map2.m_lblk = map->m_lblk + map->m_len;
502	map2.m_len = orig_mlen - map->m_len;
503	map2.m_flags = `0`;
504	retval = ext4_ext_map_blocks(handle, inode, map: &map2, flags: `0`);
505
506	if (retval <= `0`) {
507	ext4_es_insert_extent(inode, lblk: map->m_lblk, len: map->m_len,
508	pblk: map->m_pblk, status, delalloc_reserve_used: false);
509	return map->m_len;
510	}
511
512	if (unlikely(retval != map2.m_len)) {
513	ext4_warning(inode->i_sb,
514	"ES len assertion failed for inode "
515	"%lu: retval %d != map->m_len %d",
516	inode->i_ino, retval, map2.m_len);
517	WARN_ON(`1`);
518	}
519
520	status2 = map2.m_flags & EXT4_MAP_UNWRITTEN ?
521	EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
522
523	/*
524	* If map2 is contiguous with map, then let's insert it as a single
525	* extent in es cache and return the combined length of both the maps.
526	*/
527	if (map->m_pblk + map->m_len == map2.m_pblk &&
528	status == status2) {
529	ext4_es_insert_extent(inode, lblk: map->m_lblk,
530	len: map->m_len + map2.m_len, pblk: map->m_pblk,
531	status, delalloc_reserve_used: false);
532	map->m_len += map2.m_len;
533	} else {
534	ext4_es_insert_extent(inode, lblk: map->m_lblk, len: map->m_len,
535	pblk: map->m_pblk, status, delalloc_reserve_used: false);
536	}
537
538	return map->m_len;
539	}
540
541	static int ext4_map_query_blocks(handle_t handle, struct* inode *inode,
542	struct ext4_map_blocks map, int* flags)
543	{
544	unsigned int status;
545	int retval;
546	unsigned int orig_mlen = map->m_len;
547
548	flags &= EXT4_EX_QUERY_FILTER;
549	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
550	retval = ext4_ext_map_blocks(handle, inode, map, flags);
551	else
552	retval = ext4_ind_map_blocks(handle, inode, map, flags);
553
554	if (retval <= `0`)
555	return retval;
556
557	if (unlikely(retval != map->m_len)) {
558	ext4_warning(inode->i_sb,
559	"ES len assertion failed for inode "
560	"%lu: retval %d != map->m_len %d",
561	inode->i_ino, retval, map->m_len);
562	WARN_ON(`1`);
563	}
564
565	/*
566	* No need to query next in leaf:
567	* - if returned extent is not last in leaf or
568	* - if the last in leaf is the full requested range
569	*/
570	if (!(map->m_flags & EXT4_MAP_QUERY_LAST_IN_LEAF) \|\|
571	map->m_len == orig_mlen) {
572	status = map->m_flags & EXT4_MAP_UNWRITTEN ?
573	EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
574	ext4_es_insert_extent(inode, lblk: map->m_lblk, len: map->m_len,
575	pblk: map->m_pblk, status, delalloc_reserve_used: false);
576	return retval;
577	}
578
579	return ext4_map_query_blocks_next_in_leaf(handle, inode, map,
580	orig_mlen);
581	}
582
583	static int ext4_map_create_blocks(handle_t handle, struct* inode *inode,
584	struct ext4_map_blocks map, int* flags)
585	{
586	struct extent_status es;
587	unsigned int status;
588	int err, retval = `0`;
589
590	/*
591	* We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE
592	* indicates that the blocks and quotas has already been
593	* checked when the data was copied into the page cache.
594	*/
595	if (map->m_flags & EXT4_MAP_DELAYED)
596	flags \|= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
597
598	/*
599	* Here we clear m_flags because after allocating an new extent,
600	* it will be set again.
601	*/
602	map->m_flags &= ~EXT4_MAP_FLAGS;
603
604	/*
605	* We need to check for EXT4 here because migrate could have
606	* changed the inode type in between.
607	*/
608	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS)) {
609	retval = ext4_ext_map_blocks(handle, inode, map, flags);
610	} else {
611	retval = ext4_ind_map_blocks(handle, inode, map, flags);
612
613	/*
614	* We allocated new blocks which will result in i_data's
615	* format changing. Force the migrate to fail by clearing
616	* migrate flags.
617	*/
618	if (retval > `0` && map->m_flags & EXT4_MAP_NEW)
619	ext4_clear_inode_state(inode, bit: EXT4_STATE_EXT_MIGRATE);
620	}
621	if (retval <= `0`)
622	return retval;
623
624	if (unlikely(retval != map->m_len)) {
625	ext4_warning(inode->i_sb,
626	"ES len assertion failed for inode %lu: "
627	"retval %d != map->m_len %d",
628	inode->i_ino, retval, map->m_len);
629	WARN_ON(`1`);
630	}
631
632	/*
633	* We have to zeroout blocks before inserting them into extent
634	* status tree. Otherwise someone could look them up there and
635	* use them before they are really zeroed. We also have to
636	* unmap metadata before zeroing as otherwise writeback can
637	* overwrite zeros with stale data from block device.
638	*/
639	if (flags & EXT4_GET_BLOCKS_ZERO &&
640	map->m_flags & EXT4_MAP_MAPPED && map->m_flags & EXT4_MAP_NEW) {
641	err = ext4_issue_zeroout(inode, lblk: map->m_lblk, pblk: map->m_pblk,
642	len: map->m_len);
643	if (err)
644	return err;
645	}
646
647	/*
648	* If the extent has been zeroed out, we don't need to update
649	* extent status tree.
650	*/
651	if (flags & EXT4_GET_BLOCKS_PRE_IO &&
652	ext4_es_lookup_extent(inode, lblk: map->m_lblk, NULL, es: &es)) {
653	if (ext4_es_is_written(es: &es))
654	return retval;
655	}
656
657	status = map->m_flags & EXT4_MAP_UNWRITTEN ?
658	EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
659	ext4_es_insert_extent(inode, lblk: map->m_lblk, len: map->m_len, pblk: map->m_pblk,
660	status, delalloc_reserve_used: flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE);
661
662	return retval;
663	}
664
665	/*
666	* The ext4_map_blocks() function tries to look up the requested blocks,
667	* and returns if the blocks are already mapped.
668	*
669	* Otherwise it takes the write lock of the i_data_sem and allocate blocks
670	* and store the allocated blocks in the result buffer head and mark it
671	* mapped.
672	*
673	* If file type is extents based, it will call ext4_ext_map_blocks(),
674	* Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
675	* based files
676	*
677	* On success, it returns the number of blocks being mapped or allocated.
678	* If flags doesn't contain EXT4_GET_BLOCKS_CREATE the blocks are
679	* pre-allocated and unwritten, the resulting @map is marked as unwritten.
680	* If the flags contain EXT4_GET_BLOCKS_CREATE, it will mark @map as mapped.
681	*
682	* It returns 0 if plain look up failed (blocks have not been allocated), in
683	* that case, @map is returned as unmapped but we still do fill map->m_len to
684	* indicate the length of a hole starting at map->m_lblk.
685	*
686	* It returns the error in case of allocation failure.
687	*/
688	int ext4_map_blocks(handle_t handle, struct* inode *inode,
689	struct ext4_map_blocks map, int* flags)
690	{
691	struct extent_status es;
692	int retval;
693	int ret = `0`;
694	unsigned int orig_mlen = map->m_len;
695	#ifdef ES_AGGRESSIVE_TEST
696	struct ext4_map_blocks orig_map;
697
698	memcpy(&orig_map, map, sizeof(*map));
699	#endif
700
701	map->m_flags = `0`;
702	ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
703	flags, map->m_len, (unsigned long) map->m_lblk);
704
705	/*
706	* ext4_map_blocks returns an int, and m_len is an unsigned int
707	*/
708	if (unlikely(map->m_len > INT_MAX))
709	map->m_len = INT_MAX;
710
711	/ We can handle the block number less than EXT_MAX_BLOCKS /
712	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
713	return -EFSCORRUPTED;
714
715	/*
716	* Callers from the context of data submission are the only exceptions
717	* for regular files that do not hold the i_rwsem or invalidate_lock.
718	* However, caching unrelated ranges is not permitted.
719	*/
720	if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
721	WARN_ON_ONCE(!(flags & EXT4_EX_NOCACHE));
722	else
723	ext4_check_map_extents_env(inode);
724
725	/ Lookup extent status tree firstly /
726	if (ext4_es_lookup_extent(inode, lblk: map->m_lblk, NULL, es: &es)) {
727	if (ext4_es_is_written(es: &es) \|\| ext4_es_is_unwritten(es: &es)) {
728	map->m_pblk = ext4_es_pblock(es: &es) +
729	map->m_lblk - es.es_lblk;
730	map->m_flags \|= ext4_es_is_written(es: &es) ?
731	EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
732	retval = es.es_len - (map->m_lblk - es.es_lblk);
733	if (retval > map->m_len)
734	retval = map->m_len;
735	map->m_len = retval;
736	} else if (ext4_es_is_delayed(es: &es) \|\| ext4_es_is_hole(es: &es)) {
737	map->m_pblk = `0`;
738	map->m_flags \|= ext4_es_is_delayed(es: &es) ?
739	EXT4_MAP_DELAYED : `0`;
740	retval = es.es_len - (map->m_lblk - es.es_lblk);
741	if (retval > map->m_len)
742	retval = map->m_len;
743	map->m_len = retval;
744	retval = `0`;
745	} else {
746	BUG();
747	}
748
749	if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
750	return retval;
751	#ifdef ES_AGGRESSIVE_TEST
752	ext4_map_blocks_es_recheck(handle, inode, map,
753	&orig_map, flags);
754	#endif
755	if (!(flags & EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF) \|\|
756	orig_mlen == map->m_len)
757	goto found;
758
759	map->m_len = orig_mlen;
760	}
761	/*
762	* In the query cache no-wait mode, nothing we can do more if we
763	* cannot find extent in the cache.
764	*/
765	if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
766	return `0`;
767
768	/*
769	* Try to see if we can get the block without requesting a new
770	* file system block.
771	*/
772	down_read(sem: &EXT4_I(inode)->i_data_sem);
773	retval = ext4_map_query_blocks(handle, inode, map, flags);
774	up_read(sem: (&EXT4_I(inode)->i_data_sem));
775
776	found:
777	if (retval > `0` && map->m_flags & EXT4_MAP_MAPPED) {
778	ret = check_block_validity(inode, map);
779	if (ret != `0`)
780	return ret;
781	}
782
783	/ If it is only a block(s) look up /
784	if ((flags & EXT4_GET_BLOCKS_CREATE) == `0`)
785	return retval;
786
787	/*
788	* Returns if the blocks have already allocated
789	*
790	* Note that if blocks have been preallocated
791	* ext4_ext_map_blocks() returns with buffer head unmapped
792	*/
793	if (retval > `0` && map->m_flags & EXT4_MAP_MAPPED)
794	/*
795	* If we need to convert extent to unwritten
796	* we continue and do the actual work in
797	* ext4_ext_map_blocks()
798	*/
799	if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
800	return retval;
801
802
803	ext4_fc_track_inode(handle, inode);
804	/*
805	* New blocks allocate and/or writing to unwritten extent
806	* will possibly result in updating i_data, so we take
807	* the write lock of i_data_sem, and call get_block()
808	* with create == 1 flag.
809	*/
810	down_write(sem: &EXT4_I(inode)->i_data_sem);
811	retval = ext4_map_create_blocks(handle, inode, map, flags);
812	up_write(sem: (&EXT4_I(inode)->i_data_sem));
813	if (retval > `0` && map->m_flags & EXT4_MAP_MAPPED) {
814	ret = check_block_validity(inode, map);
815	if (ret != `0`)
816	return ret;
817
818	/*
819	* Inodes with freshly allocated blocks where contents will be
820	* visible after transaction commit must be on transaction's
821	* ordered data list.
822	*/
823	if (map->m_flags & EXT4_MAP_NEW &&
824	!(map->m_flags & EXT4_MAP_UNWRITTEN) &&
825	!(flags & EXT4_GET_BLOCKS_ZERO) &&
826	!ext4_is_quota_file(inode) &&
827	ext4_should_order_data(inode)) {
828	loff_t start_byte =
829	(loff_t)map->m_lblk << inode->i_blkbits;
830	loff_t length = (loff_t)map->m_len << inode->i_blkbits;
831
832	if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
833	ret = ext4_jbd2_inode_add_wait(handle, inode,
834	start_byte, length);
835	else
836	ret = ext4_jbd2_inode_add_write(handle, inode,
837	start_byte, length);
838	if (ret)
839	return ret;
840	}
841	}
842	if (retval > `0` && (map->m_flags & EXT4_MAP_UNWRITTEN \|\|
843	map->m_flags & EXT4_MAP_MAPPED))
844	ext4_fc_track_range(handle, inode, start: map->m_lblk,
845	end: map->m_lblk + map->m_len - `1`);
846	if (retval < `0`)
847	ext_debug(inode, "failed with err %d\n", retval);
848	return retval;
849	}
850
851	/*
852	* Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
853	* we have to be careful as someone else may be manipulating b_state as well.
854	*/
855	static void ext4_update_bh_state(struct buffer_head bh, unsigned* long flags)
856	{
857	unsigned long old_state;
858	unsigned long new_state;
859
860	flags &= EXT4_MAP_FLAGS;
861
862	/ Dummy buffer_head? Set non-atomically. /
863	if (!bh->b_folio) {
864	bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) \| flags;
865	return;
866	}
867	/*
868	* Someone else may be modifying b_state. Be careful! This is ugly but
869	* once we get rid of using bh as a container for mapping information
870	* to pass to / from get_block functions, this can go away.
871	*/
872	old_state = READ_ONCE(bh->b_state);
873	do {
874	new_state = (old_state & ~EXT4_MAP_FLAGS) \| flags;
875	} while (unlikely(!try_cmpxchg(&bh->b_state, &old_state, new_state)));
876	}
877
878	/*
879	* Make sure that the current journal transaction has enough credits to map
880	* one extent. Return -EAGAIN if it cannot extend the current running
881	* transaction.
882	*/
883	static inline int ext4_journal_ensure_extent_credits(handle_t *handle,
884	struct inode *inode)
885	{
886	int credits;
887	int ret;
888
889	/ Called from ext4_da_write_begin() which has no handle started? /
890	if (!handle)
891	return `0`;
892
893	credits = ext4_chunk_trans_blocks(inode, nrblocks: `1`);
894	ret = __ext4_journal_ensure_credits(handle, check_cred: credits, extend_cred: credits, revoke_cred: `0`);
895	return ret <= `0` ? ret : -EAGAIN;
896	}
897
898	static int _ext4_get_block(struct inode *inode, sector_t iblock,
899	struct buffer_head bh, int* flags)
900	{
901	struct ext4_map_blocks map;
902	int ret = `0`;
903
904	if (ext4_has_inline_data(inode))
905	return -ERANGE;
906
907	map.m_lblk = iblock;
908	map.m_len = bh->b_size >> inode->i_blkbits;
909
910	ret = ext4_map_blocks(handle: ext4_journal_current_handle(), inode, map: &map,
911	flags);
912	if (ret > `0`) {
913	map_bh(bh, sb: inode->i_sb, block: map.m_pblk);
914	ext4_update_bh_state(bh, flags: map.m_flags);
915	bh->b_size = inode->i_sb->s_blocksize * map.m_len;
916	ret = `0`;
917	} else if (ret == `0`) {
918	/ hole case, need to fill in bh->b_size /
919	bh->b_size = inode->i_sb->s_blocksize * map.m_len;
920	}
921	return ret;
922	}
923
924	int ext4_get_block(struct inode *inode, sector_t iblock,
925	struct buffer_head bh, int* create)
926	{
927	return _ext4_get_block(inode, iblock, bh,
928	flags: create ? EXT4_GET_BLOCKS_CREATE : `0`);
929	}
930
931	/*
932	* Get block function used when preparing for buffered write if we require
933	* creating an unwritten extent if blocks haven't been allocated. The extent
934	* will be converted to written after the IO is complete.
935	*/
936	int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
937	struct buffer_head bh_result, int* create)
938	{
939	int ret = `0`;
940
941	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
942	inode->i_ino, create);
943	ret = _ext4_get_block(inode, iblock, bh: bh_result,
944	EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
945
946	/*
947	* If the buffer is marked unwritten, mark it as new to make sure it is
948	* zeroed out correctly in case of partial writes. Otherwise, there is
949	* a chance of stale data getting exposed.
950	*/
951	if (ret == `0` && buffer_unwritten(bh: bh_result))
952	set_buffer_new(bh_result);
953
954	return ret;
955	}
956
957	/ Maximum number of blocks we map for direct IO at once. /
958	#define DIO_MAX_BLOCKS 4096
959
960	/*
961	* `handle' can be NULL if create is zero
962	*/
963	struct buffer_head ext4_getblk(handle_t handle, struct inode *inode,
964	ext4_lblk_t block, int map_flags)
965	{
966	struct ext4_map_blocks map;
967	struct buffer_head *bh;
968	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
969	bool nowait = map_flags & EXT4_GET_BLOCKS_CACHED_NOWAIT;
970	int err;
971
972	ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
973	\|\| handle != NULL \|\| create == `0`);
974	ASSERT(create == `0` \|\| !nowait);
975
976	map.m_lblk = block;
977	map.m_len = `1`;
978	err = ext4_map_blocks(handle, inode, map: &map, flags: map_flags);
979
980	if (err == `0`)
981	return create ? ERR_PTR(error: -ENOSPC) : NULL;
982	if (err < `0`)
983	return ERR_PTR(error: err);
984
985	if (nowait)
986	return sb_find_get_block(sb: inode->i_sb, block: map.m_pblk);
987
988	/*
989	* Since bh could introduce extra ref count such as referred by
990	* journal_head etc. Try to avoid using __GFP_MOVABLE here
991	* as it may fail the migration when journal_head remains.
992	*/
993	bh = getblk_unmovable(bdev: inode->i_sb->s_bdev, block: map.m_pblk,
994	size: inode->i_sb->s_blocksize);
995
996	if (unlikely(!bh))
997	return ERR_PTR(error: -ENOMEM);
998	if (map.m_flags & EXT4_MAP_NEW) {
999	ASSERT(create != `0`);
1000	ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
1001	\|\| (handle != NULL));
1002
1003	/*
1004	* Now that we do not always journal data, we should
1005	* keep in mind whether this should always journal the
1006	* new buffer as metadata. For now, regular file
1007	* writes use ext4_get_block instead, so it's not a
1008	* problem.
1009	*/
1010	lock_buffer(bh);
1011	BUFFER_TRACE(bh, "call get_create_access");
1012	err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
1013	EXT4_JTR_NONE);
1014	if (unlikely(err)) {
1015	unlock_buffer(bh);
1016	goto errout;
1017	}
1018	if (!buffer_uptodate(bh)) {
1019	memset(s: bh->b_data, c: `0`, n: inode->i_sb->s_blocksize);
1020	set_buffer_uptodate(bh);
1021	}
1022	unlock_buffer(bh);
1023	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1024	err = ext4_handle_dirty_metadata(handle, inode, bh);
1025	if (unlikely(err))
1026	goto errout;
1027	} else
1028	BUFFER_TRACE(bh, "not a new buffer");
1029	return bh;
1030	errout:
1031	brelse(bh);
1032	return ERR_PTR(error: err);
1033	}
1034
1035	struct buffer_head ext4_bread(handle_t handle, struct inode *inode,
1036	ext4_lblk_t block, int map_flags)
1037	{
1038	struct buffer_head *bh;
1039	int ret;
1040
1041	bh = ext4_getblk(handle, inode, block, map_flags);
1042	if (IS_ERR(ptr: bh))
1043	return bh;
1044	if (!bh \|\| ext4_buffer_uptodate(bh))
1045	return bh;
1046
1047	ret = ext4_read_bh_lock(bh, REQ_META \| REQ_PRIO, wait: true);
1048	if (ret) {
1049	put_bh(bh);
1050	return ERR_PTR(error: ret);
1051	}
1052	return bh;
1053	}
1054
1055	/ Read a contiguous batch of blocks. /
1056	int ext4_bread_batch(struct inode inode, ext4_lblk_t block, int* bh_count,
1057	bool wait, struct buffer_head **bhs)
1058	{
1059	int i, err;
1060
1061	for (i = `0`; i < bh_count; i++) {
1062	bhs[i] = ext4_getblk(NULL, inode, block: block + i, map_flags: `0` / map_flags /);
1063	if (IS_ERR(ptr: bhs[i])) {
1064	err = PTR_ERR(ptr: bhs[i]);
1065	bh_count = i;
1066	goto out_brelse;
1067	}
1068	}
1069
1070	for (i = `0`; i < bh_count; i++)
1071	/ Note that NULL bhs[i] is valid because of holes. /
1072	if (bhs[i] && !ext4_buffer_uptodate(bh: bhs[i]))
1073	ext4_read_bh_lock(bh: bhs[i], REQ_META \| REQ_PRIO, wait: false);
1074
1075	if (!wait)
1076	return `0`;
1077
1078	for (i = `0`; i < bh_count; i++)
1079	if (bhs[i])
1080	wait_on_buffer(bh: bhs[i]);
1081
1082	for (i = `0`; i < bh_count; i++) {
1083	if (bhs[i] && !buffer_uptodate(bh: bhs[i])) {
1084	err = -EIO;
1085	goto out_brelse;
1086	}
1087	}
1088	return `0`;
1089
1090	out_brelse:
1091	for (i = `0`; i < bh_count; i++) {
1092	brelse(bh: bhs[i]);
1093	bhs[i] = NULL;
1094	}
1095	return err;
1096	}
1097
1098	int ext4_walk_page_buffers(handle_t handle, struct* inode *inode,
1099	struct buffer_head *head,
1100	unsigned from,
1101	unsigned to,
1102	int *partial,
1103	int (fn)(handle_t handle, struct inode *inode,
1104	struct buffer_head *bh))
1105	{
1106	struct buffer_head *bh;
1107	unsigned block_start, block_end;
1108	unsigned blocksize = head->b_size;
1109	int err, ret = `0`;
1110	struct buffer_head *next;
1111
1112	for (bh = head, block_start = `0`;
1113	ret == `0` && (bh != head \|\| !block_start);
1114	block_start = block_end, bh = next) {
1115	next = bh->b_this_page;
1116	block_end = block_start + blocksize;
1117	if (block_end <= from \|\| block_start >= to) {
1118	if (partial && !buffer_uptodate(bh))
1119	*partial = `1`;
1120	continue;
1121	}
1122	err = (*fn)(handle, inode, bh);
1123	if (!ret)
1124	ret = err;
1125	}
1126	return ret;
1127	}
1128
1129	/*
1130	* Helper for handling dirtying of journalled data. We also mark the folio as
1131	* dirty so that writeback code knows about this page (and inode) contains
1132	* dirty data. ext4_writepages() then commits appropriate transaction to
1133	* make data stable.
1134	*/
1135	static int ext4_dirty_journalled_data(handle_t handle, struct* buffer_head *bh)
1136	{
1137	struct folio *folio = bh->b_folio;
1138	struct inode *inode = folio->mapping->host;
1139
1140	/ only regular files have a_ops /
1141	if (S_ISREG(inode->i_mode))
1142	folio_mark_dirty(folio);
1143	return ext4_handle_dirty_metadata(handle, NULL, bh);
1144	}
1145
1146	int do_journal_get_write_access(handle_t handle, struct* inode *inode,
1147	struct buffer_head *bh)
1148	{
1149	if (!buffer_mapped(bh) \|\| buffer_freed(bh))
1150	return `0`;
1151	BUFFER_TRACE(bh, "get write access");
1152	return ext4_journal_get_write_access(handle, inode->i_sb, bh,
1153	EXT4_JTR_NONE);
1154	}
1155
1156	int ext4_block_write_begin(handle_t handle, struct* folio *folio,
1157	loff_t pos, unsigned len,
1158	get_block_t *get_block)
1159	{
1160	unsigned int from = offset_in_folio(folio, pos);
1161	unsigned to = from + len;
1162	struct inode *inode = folio->mapping->host;
1163	unsigned block_start, block_end;
1164	sector_t block;
1165	int err = `0`;
1166	unsigned blocksize = inode->i_sb->s_blocksize;
1167	unsigned bbits;
1168	struct buffer_head bh, head, *wait[`2`];
1169	int nr_wait = `0`;
1170	int i;
1171	bool should_journal_data = ext4_should_journal_data(inode);
1172
1173	BUG_ON(!folio_test_locked(folio));
1174	BUG_ON(to > folio_size(folio));
1175	BUG_ON(from > to);
1176
1177	head = folio_buffers(folio);
1178	if (!head)
1179	head = create_empty_buffers(folio, blocksize, b_state: `0`);
1180	bbits = ilog2(blocksize);
1181	block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
1182
1183	for (bh = head, block_start = `0`; bh != head \|\| !block_start;
1184	block++, block_start = block_end, bh = bh->b_this_page) {
1185	block_end = block_start + blocksize;
1186	if (block_end <= from \|\| block_start >= to) {
1187	if (folio_test_uptodate(folio)) {
1188	set_buffer_uptodate(bh);
1189	}
1190	continue;
1191	}
1192	if (WARN_ON_ONCE(buffer_new(bh)))
1193	clear_buffer_new(bh);
1194	if (!buffer_mapped(bh)) {
1195	WARN_ON(bh->b_size != blocksize);
1196	err = ext4_journal_ensure_extent_credits(handle, inode);
1197	if (!err)
1198	err = get_block(inode, block, bh, `1`);
1199	if (err)
1200	break;
1201	if (buffer_new(bh)) {
1202	/*
1203	* We may be zeroing partial buffers or all new
1204	* buffers in case of failure. Prepare JBD2 for
1205	* that.
1206	*/
1207	if (should_journal_data)
1208	do_journal_get_write_access(handle,
1209	inode, bh);
1210	if (folio_test_uptodate(folio)) {
1211	/*
1212	* Unlike __block_write_begin() we leave
1213	* dirtying of new uptodate buffers to
1214	* ->write_end() time or
1215	* folio_zero_new_buffers().
1216	*/
1217	set_buffer_uptodate(bh);
1218	continue;
1219	}
1220	if (block_end > to \|\| block_start < from)
1221	folio_zero_segments(folio, start1: to,
1222	xend1: block_end,
1223	start2: block_start, xend2: from);
1224	continue;
1225	}
1226	}
1227	if (folio_test_uptodate(folio)) {
1228	set_buffer_uptodate(bh);
1229	continue;
1230	}
1231	if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1232	!buffer_unwritten(bh) &&
1233	(block_start < from \|\| block_end > to)) {
1234	ext4_read_bh_lock(bh, op_flags: `0`, wait: false);
1235	wait[nr_wait++] = bh;
1236	}
1237	}
1238	/*
1239	* If we issued read requests, let them complete.
1240	*/
1241	for (i = `0`; i < nr_wait; i++) {
1242	wait_on_buffer(bh: wait[i]);
1243	if (!buffer_uptodate(bh: wait[i]))
1244	err = -EIO;
1245	}
1246	if (unlikely(err)) {
1247	if (should_journal_data)
1248	ext4_journalled_zero_new_buffers(handle, inode, folio,
1249	from, to);
1250	else
1251	folio_zero_new_buffers(folio, from, to);
1252	} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1253	for (i = `0`; i < nr_wait; i++) {
1254	int err2;
1255
1256	err2 = fscrypt_decrypt_pagecache_blocks(folio,
1257	len: blocksize, offs: bh_offset(bh: wait[i]));
1258	if (err2) {
1259	clear_buffer_uptodate(bh: wait[i]);
1260	err = err2;
1261	}
1262	}
1263	}
1264
1265	return err;
1266	}
1267
1268	/*
1269	* To preserve ordering, it is essential that the hole instantiation and
1270	* the data write be encapsulated in a single transaction. We cannot
1271	* close off a transaction and start a new one between the ext4_get_block()
1272	* and the ext4_write_end(). So doing the jbd2_journal_start at the start of
1273	* ext4_write_begin() is the right place.
1274	*/
1275	static int ext4_write_begin(const struct kiocb *iocb,
1276	struct address_space *mapping,
1277	loff_t pos, unsigned len,
1278	struct folio *foliop, void* **fsdata)
1279	{
1280	struct inode *inode = mapping->host;
1281	int ret, needed_blocks;
1282	handle_t *handle;
1283	int retries = `0`;
1284	struct folio *folio;
1285	pgoff_t index;
1286	unsigned from, to;
1287
1288	ret = ext4_emergency_state(sb: inode->i_sb);
1289	if (unlikely(ret))
1290	return ret;
1291
1292	trace_ext4_write_begin(inode, pos, len);
1293	/*
1294	* Reserve one block more for addition to orphan list in case
1295	* we allocate blocks but write fails for some reason
1296	*/
1297	needed_blocks = ext4_chunk_trans_extent(inode,
1298	nrblocks: ext4_journal_blocks_per_folio(inode)) + `1`;
1299	index = pos >> PAGE_SHIFT;
1300
1301	if (ext4_test_inode_state(inode, bit: EXT4_STATE_MAY_INLINE_DATA)) {
1302	ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1303	foliop);
1304	if (ret < `0`)
1305	return ret;
1306	if (ret == `1`)
1307	return `0`;
1308	}
1309
1310	/*
1311	* write_begin_get_folio() can take a long time if the
1312	* system is thrashing due to memory pressure, or if the folio
1313	* is being written back. So grab it first before we start
1314	* the transaction handle. This also allows us to allocate
1315	* the folio (if needed) without using GFP_NOFS.
1316	*/
1317	retry_grab:
1318	folio = write_begin_get_folio(iocb, mapping, index, len);
1319	if (IS_ERR(ptr: folio))
1320	return PTR_ERR(ptr: folio);
1321
1322	if (pos + len > folio_pos(folio) + folio_size(folio))
1323	len = folio_pos(folio) + folio_size(folio) - pos;
1324
1325	from = offset_in_folio(folio, pos);
1326	to = from + len;
1327
1328	/*
1329	* The same as page allocation, we prealloc buffer heads before
1330	* starting the handle.
1331	*/
1332	if (!folio_buffers(folio))
1333	create_empty_buffers(folio, blocksize: inode->i_sb->s_blocksize, b_state: `0`);
1334
1335	folio_unlock(folio);
1336
1337	retry_journal:
1338	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1339	if (IS_ERR(ptr: handle)) {
1340	folio_put(folio);
1341	return PTR_ERR(ptr: handle);
1342	}
1343
1344	folio_lock(folio);
1345	if (folio->mapping != mapping) {
1346	/ The folio got truncated from under us /
1347	folio_unlock(folio);
1348	folio_put(folio);
1349	ext4_journal_stop(handle);
1350	goto retry_grab;
1351	}
1352	/ In case writeback began while the folio was unlocked /
1353	folio_wait_stable(folio);
1354
1355	if (ext4_should_dioread_nolock(inode))
1356	ret = ext4_block_write_begin(handle, folio, pos, len,
1357	get_block: ext4_get_block_unwritten);
1358	else
1359	ret = ext4_block_write_begin(handle, folio, pos, len,
1360	get_block: ext4_get_block);
1361	if (!ret && ext4_should_journal_data(inode)) {
1362	ret = ext4_walk_page_buffers(handle, inode,
1363	folio_buffers(folio), from, to,
1364	NULL, fn: do_journal_get_write_access);
1365	}
1366
1367	if (ret) {
1368	bool extended = (pos + len > inode->i_size) &&
1369	!ext4_verity_in_progress(inode);
1370
1371	folio_unlock(folio);
1372	/*
1373	* ext4_block_write_begin may have instantiated a few blocks
1374	* outside i_size. Trim these off again. Don't need
1375	* i_size_read because we hold i_rwsem.
1376	*
1377	* Add inode to orphan list in case we crash before
1378	* truncate finishes
1379	*/
1380	if (extended && ext4_can_truncate(inode))
1381	ext4_orphan_add(handle, inode);
1382
1383	ext4_journal_stop(handle);
1384	if (extended) {
1385	ext4_truncate_failed_write(inode);
1386	/*
1387	* If truncate failed early the inode might
1388	* still be on the orphan list; we need to
1389	* make sure the inode is removed from the
1390	* orphan list in that case.
1391	*/
1392	if (inode->i_nlink)
1393	ext4_orphan_del(NULL, inode);
1394	}
1395
1396	if (ret == -EAGAIN \|\|
1397	(ret == -ENOSPC &&
1398	ext4_should_retry_alloc(sb: inode->i_sb, retries: &retries)))
1399	goto retry_journal;
1400	folio_put(folio);
1401	return ret;
1402	}
1403	*foliop = folio;
1404	return ret;
1405	}
1406
1407	/ For write_end() in data=journal mode /
1408	static int write_end_fn(handle_t handle, struct* inode *inode,
1409	struct buffer_head *bh)
1410	{
1411	int ret;
1412	if (!buffer_mapped(bh) \|\| buffer_freed(bh))
1413	return `0`;
1414	set_buffer_uptodate(bh);
1415	ret = ext4_dirty_journalled_data(handle, bh);
1416	clear_buffer_meta(bh);
1417	clear_buffer_prio(bh);
1418	clear_buffer_new(bh);
1419	return ret;
1420	}
1421
1422	/*
1423	* We need to pick up the new inode size which generic_commit_write gave us
1424	* `iocb` can be NULL - eg, when called from page_symlink().
1425	*
1426	* ext4 never places buffers on inode->i_mapping->i_private_list. metadata
1427	* buffers are managed internally.
1428	*/
1429	static int ext4_write_end(const struct kiocb *iocb,
1430	struct address_space *mapping,
1431	loff_t pos, unsigned len, unsigned copied,
1432	struct folio folio, void* *fsdata)
1433	{
1434	handle_t *handle = ext4_journal_current_handle();
1435	struct inode *inode = mapping->host;
1436	loff_t old_size = inode->i_size;
1437	int ret = `0`, ret2;
1438	int i_size_changed = `0`;
1439	bool verity = ext4_verity_in_progress(inode);
1440
1441	trace_ext4_write_end(inode, pos, len, copied);
1442
1443	if (ext4_has_inline_data(inode) &&
1444	ext4_test_inode_state(inode, bit: EXT4_STATE_MAY_INLINE_DATA))
1445	return ext4_write_inline_data_end(inode, pos, len, copied,
1446	folio);
1447
1448	copied = block_write_end(pos, len, copied, folio);
1449	/*
1450	* it's important to update i_size while still holding folio lock:
1451	* page writeout could otherwise come in and zero beyond i_size.
1452	*
1453	* If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1454	* blocks are being written past EOF, so skip the i_size update.
1455	*/
1456	if (!verity)
1457	i_size_changed = ext4_update_inode_size(inode, newsize: pos + copied);
1458	folio_unlock(folio);
1459	folio_put(folio);
1460
1461	if (old_size < pos && !verity) {
1462	pagecache_isize_extended(inode, from: old_size, to: pos);
1463	ext4_zero_partial_blocks(handle, inode, lstart: old_size, lend: pos - old_size);
1464	}
1465	/*
1466	* Don't mark the inode dirty under folio lock. First, it unnecessarily
1467	* makes the holding time of folio lock longer. Second, it forces lock
1468	* ordering of folio lock and transaction start for journaling
1469	* filesystems.
1470	*/
1471	if (i_size_changed)
1472	ret = ext4_mark_inode_dirty(handle, inode);
1473
1474	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1475	/ if we have allocated more blocks and copied*
1476	* less. We will have blocks allocated outside
1477	* inode->i_size. So truncate them
1478	*/
1479	ext4_orphan_add(handle, inode);
1480
1481	ret2 = ext4_journal_stop(handle);
1482	if (!ret)
1483	ret = ret2;
1484
1485	if (pos + len > inode->i_size && !verity) {
1486	ext4_truncate_failed_write(inode);
1487	/*
1488	* If truncate failed early the inode might still be
1489	* on the orphan list; we need to make sure the inode
1490	* is removed from the orphan list in that case.
1491	*/
1492	if (inode->i_nlink)
1493	ext4_orphan_del(NULL, inode);
1494	}
1495
1496	return ret ? ret : copied;
1497	}
1498
1499	/*
1500	* This is a private version of folio_zero_new_buffers() which doesn't
1501	* set the buffer to be dirty, since in data=journalled mode we need
1502	* to call ext4_dirty_journalled_data() instead.
1503	*/
1504	static void ext4_journalled_zero_new_buffers(handle_t *handle,
1505	struct inode *inode,
1506	struct folio *folio,
1507	unsigned from, unsigned to)
1508	{
1509	unsigned int block_start = `0`, block_end;
1510	struct buffer_head head, bh;
1511
1512	bh = head = folio_buffers(folio);
1513	do {
1514	block_end = block_start + bh->b_size;
1515	if (buffer_new(bh)) {
1516	if (block_end > from && block_start < to) {
1517	if (!folio_test_uptodate(folio)) {
1518	unsigned start, size;
1519
1520	start = max(from, block_start);
1521	size = min(to, block_end) - start;
1522
1523	folio_zero_range(folio, start, length: size);
1524	}
1525	clear_buffer_new(bh);
1526	write_end_fn(handle, inode, bh);
1527	}
1528	}
1529	block_start = block_end;
1530	bh = bh->b_this_page;
1531	} while (bh != head);
1532	}
1533
1534	static int ext4_journalled_write_end(const struct kiocb *iocb,
1535	struct address_space *mapping,
1536	loff_t pos, unsigned len, unsigned copied,
1537	struct folio folio, void* *fsdata)
1538	{
1539	handle_t *handle = ext4_journal_current_handle();
1540	struct inode *inode = mapping->host;
1541	loff_t old_size = inode->i_size;
1542	int ret = `0`, ret2;
1543	int partial = `0`;
1544	unsigned from, to;
1545	int size_changed = `0`;
1546	bool verity = ext4_verity_in_progress(inode);
1547
1548	trace_ext4_journalled_write_end(inode, pos, len, copied);
1549	from = pos & (PAGE_SIZE - `1`);
1550	to = from + len;
1551
1552	BUG_ON(!ext4_handle_valid(handle));
1553
1554	if (ext4_has_inline_data(inode))
1555	return ext4_write_inline_data_end(inode, pos, len, copied,
1556	folio);
1557
1558	if (unlikely(copied < len) && !folio_test_uptodate(folio)) {
1559	copied = `0`;
1560	ext4_journalled_zero_new_buffers(handle, inode, folio,
1561	from, to);
1562	} else {
1563	if (unlikely(copied < len))
1564	ext4_journalled_zero_new_buffers(handle, inode, folio,
1565	from: from + copied, to);
1566	ret = ext4_walk_page_buffers(handle, inode,
1567	folio_buffers(folio),
1568	from, to: from + copied, partial: &partial,
1569	fn: write_end_fn);
1570	if (!partial)
1571	folio_mark_uptodate(folio);
1572	}
1573	if (!verity)
1574	size_changed = ext4_update_inode_size(inode, newsize: pos + copied);
1575	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1576	folio_unlock(folio);
1577	folio_put(folio);
1578
1579	if (old_size < pos && !verity) {
1580	pagecache_isize_extended(inode, from: old_size, to: pos);
1581	ext4_zero_partial_blocks(handle, inode, lstart: old_size, lend: pos - old_size);
1582	}
1583
1584	if (size_changed) {
1585	ret2 = ext4_mark_inode_dirty(handle, inode);
1586	if (!ret)
1587	ret = ret2;
1588	}
1589
1590	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1591	/ if we have allocated more blocks and copied*
1592	* less. We will have blocks allocated outside
1593	* inode->i_size. So truncate them
1594	*/
1595	ext4_orphan_add(handle, inode);
1596
1597	ret2 = ext4_journal_stop(handle);
1598	if (!ret)
1599	ret = ret2;
1600	if (pos + len > inode->i_size && !verity) {
1601	ext4_truncate_failed_write(inode);
1602	/*
1603	* If truncate failed early the inode might still be
1604	* on the orphan list; we need to make sure the inode
1605	* is removed from the orphan list in that case.
1606	*/
1607	if (inode->i_nlink)
1608	ext4_orphan_del(NULL, inode);
1609	}
1610
1611	return ret ? ret : copied;
1612	}
1613
1614	/*
1615	* Reserve space for 'nr_resv' clusters
1616	*/
1617	static int ext4_da_reserve_space(struct inode inode, int* nr_resv)
1618	{
1619	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1620	struct ext4_inode_info *ei = EXT4_I(inode);
1621	int ret;
1622
1623	/*
1624	* We will charge metadata quota at writeout time; this saves
1625	* us from metadata over-estimation, though we may go over by
1626	* a small amount in the end. Here we just reserve for data.
1627	*/
1628	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, nr_resv));
1629	if (ret)
1630	return ret;
1631
1632	spin_lock(lock: &ei->i_block_reservation_lock);
1633	if (ext4_claim_free_clusters(sbi, nclusters: nr_resv, flags: `0`)) {
1634	spin_unlock(lock: &ei->i_block_reservation_lock);
1635	dquot_release_reservation_block(inode, EXT4_C2B(sbi, nr_resv));
1636	return -ENOSPC;
1637	}
1638	ei->i_reserved_data_blocks += nr_resv;
1639	trace_ext4_da_reserve_space(inode, nr_resv);
1640	spin_unlock(lock: &ei->i_block_reservation_lock);
1641
1642	return `0`; / success /
1643	}
1644
1645	void ext4_da_release_space(struct inode inode, int* to_free)
1646	{
1647	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1648	struct ext4_inode_info *ei = EXT4_I(inode);
1649
1650	if (!to_free)
1651	return; / Nothing to release, exit /
1652
1653	spin_lock(lock: &EXT4_I(inode)->i_block_reservation_lock);
1654
1655	trace_ext4_da_release_space(inode, freed_blocks: to_free);
1656	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1657	/*
1658	* if there aren't enough reserved blocks, then the
1659	* counter is messed up somewhere. Since this
1660	* function is called from invalidate page, it's
1661	* harmless to return without any action.
1662	*/
1663	ext4_warning(inode->i_sb, "ext4_da_release_space: "
1664	"ino %lu, to_free %d with only %d reserved "
1665	"data blocks", inode->i_ino, to_free,
1666	ei->i_reserved_data_blocks);
1667	WARN_ON(`1`);
1668	to_free = ei->i_reserved_data_blocks;
1669	}
1670	ei->i_reserved_data_blocks -= to_free;
1671
1672	/ update fs dirty data blocks counter /
1673	percpu_counter_sub(fbc: &sbi->s_dirtyclusters_counter, amount: to_free);
1674
1675	spin_unlock(lock: &EXT4_I(inode)->i_block_reservation_lock);
1676
1677	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1678	}
1679
1680	/*
1681	* Delayed allocation stuff
1682	*/
1683
1684	struct mpage_da_data {
1685	/ These are input fields for ext4_do_writepages() /
1686	struct inode *inode;
1687	struct writeback_control *wbc;
1688	unsigned int can_map:`1`; / Can writepages call map blocks? /
1689
1690	/ These are internal state of ext4_do_writepages() /
1691	loff_t start_pos; / The start pos to write /
1692	loff_t next_pos; / Current pos to examine /
1693	loff_t end_pos; / Last pos to examine /
1694
1695	/*
1696	* Extent to map - this can be after start_pos because that can be
1697	* fully mapped. We somewhat abuse m_flags to store whether the extent
1698	* is delalloc or unwritten.
1699	*/
1700	struct ext4_map_blocks map;
1701	struct ext4_io_submit io_submit; / IO submission data /
1702	unsigned int do_map:`1`;
1703	unsigned int scanned_until_end:`1`;
1704	unsigned int journalled_more_data:`1`;
1705	};
1706
1707	static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1708	bool invalidate)
1709	{
1710	unsigned nr, i;
1711	pgoff_t index, end;
1712	struct folio_batch fbatch;
1713	struct inode *inode = mpd->inode;
1714	struct address_space *mapping = inode->i_mapping;
1715
1716	/ This is necessary when next_pos == 0. /
1717	if (mpd->start_pos >= mpd->next_pos)
1718	return;
1719
1720	mpd->scanned_until_end = `0`;
1721	if (invalidate) {
1722	ext4_lblk_t start, last;
1723	start = EXT4_B_TO_LBLK(inode, mpd->start_pos);
1724	last = mpd->next_pos >> inode->i_blkbits;
1725
1726	/*
1727	* avoid racing with extent status tree scans made by
1728	* ext4_insert_delayed_block()
1729	*/
1730	down_write(sem: &EXT4_I(inode)->i_data_sem);
1731	ext4_es_remove_extent(inode, lblk: start, len: last - start);
1732	up_write(sem: &EXT4_I(inode)->i_data_sem);
1733	}
1734
1735	folio_batch_init(fbatch: &fbatch);
1736	index = mpd->start_pos >> PAGE_SHIFT;
1737	end = mpd->next_pos >> PAGE_SHIFT;
1738	while (index < end) {
1739	nr = filemap_get_folios(mapping, start: &index, end: end - `1`, fbatch: &fbatch);
1740	if (nr == `0`)
1741	break;
1742	for (i = `0`; i < nr; i++) {
1743	struct folio *folio = fbatch.folios[i];
1744
1745	if (folio_pos(folio) < mpd->start_pos)
1746	continue;
1747	if (folio_next_index(folio) > end)
1748	continue;
1749	BUG_ON(!folio_test_locked(folio));
1750	BUG_ON(folio_test_writeback(folio));
1751	if (invalidate) {
1752	if (folio_mapped(folio))
1753	folio_clear_dirty_for_io(folio);
1754	block_invalidate_folio(folio, offset: `0`,
1755	length: folio_size(folio));
1756	folio_clear_uptodate(folio);
1757	}
1758	folio_unlock(folio);
1759	}
1760	folio_batch_release(fbatch: &fbatch);
1761	}
1762	}
1763
1764	static void ext4_print_free_blocks(struct inode *inode)
1765	{
1766	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1767	struct super_block *sb = inode->i_sb;
1768	struct ext4_inode_info *ei = EXT4_I(inode);
1769
1770	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1771	EXT4_C2B(EXT4_SB(inode->i_sb),
1772	ext4_count_free_clusters(sb)));
1773	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1774	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1775	(long long) EXT4_C2B(EXT4_SB(sb),
1776	percpu_counter_sum(&sbi->s_freeclusters_counter)));
1777	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1778	(long long) EXT4_C2B(EXT4_SB(sb),
1779	percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1780	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1781	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1782	ei->i_reserved_data_blocks);
1783	return;
1784	}
1785
1786	/*
1787	* Check whether the cluster containing lblk has been allocated or has
1788	* delalloc reservation.
1789	*
1790	* Returns 0 if the cluster doesn't have either, 1 if it has delalloc
1791	* reservation, 2 if it's already been allocated, negative error code on
1792	* failure.
1793	*/
1794	static int ext4_clu_alloc_state(struct inode *inode, ext4_lblk_t lblk)
1795	{
1796	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1797	int ret;
1798
1799	/ Has delalloc reservation? /
1800	if (ext4_es_scan_clu(inode, matching_fn: &ext4_es_is_delayed, lblk))
1801	return `1`;
1802
1803	/ Already been allocated? /
1804	if (ext4_es_scan_clu(inode, matching_fn: &ext4_es_is_mapped, lblk))
1805	return `2`;
1806	ret = ext4_clu_mapped(inode, EXT4_B2C(sbi, lblk));
1807	if (ret < `0`)
1808	return ret;
1809	if (ret > `0`)
1810	return `2`;
1811
1812	return `0`;
1813	}
1814
1815	/*
1816	* ext4_insert_delayed_blocks - adds a multiple delayed blocks to the extents
1817	* status tree, incrementing the reserved
1818	* cluster/block count or making pending
1819	* reservations where needed
1820	*
1821	* @inode - file containing the newly added block
1822	* @lblk - start logical block to be added
1823	* @len - length of blocks to be added
1824	*
1825	* Returns 0 on success, negative error code on failure.
1826	*/
1827	static int ext4_insert_delayed_blocks(struct inode *inode, ext4_lblk_t lblk,
1828	ext4_lblk_t len)
1829	{
1830	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1831	int ret;
1832	bool lclu_allocated = false;
1833	bool end_allocated = false;
1834	ext4_lblk_t resv_clu;
1835	ext4_lblk_t end = lblk + len - `1`;
1836
1837	/*
1838	* If the cluster containing lblk or end is shared with a delayed,
1839	* written, or unwritten extent in a bigalloc file system, it's
1840	* already been accounted for and does not need to be reserved.
1841	* A pending reservation must be made for the cluster if it's
1842	* shared with a written or unwritten extent and doesn't already
1843	* have one. Written and unwritten extents can be purged from the
1844	* extents status tree if the system is under memory pressure, so
1845	* it's necessary to examine the extent tree if a search of the
1846	* extents status tree doesn't get a match.
1847	*/
1848	if (sbi->s_cluster_ratio == `1`) {
1849	ret = ext4_da_reserve_space(inode, nr_resv: len);
1850	if (ret != `0`) / ENOSPC /
1851	return ret;
1852	} else { / bigalloc /
1853	resv_clu = EXT4_B2C(sbi, end) - EXT4_B2C(sbi, lblk) + `1`;
1854
1855	ret = ext4_clu_alloc_state(inode, lblk);
1856	if (ret < `0`)
1857	return ret;
1858	if (ret > `0`) {
1859	resv_clu--;
1860	lclu_allocated = (ret == `2`);
1861	}
1862
1863	if (EXT4_B2C(sbi, lblk) != EXT4_B2C(sbi, end)) {
1864	ret = ext4_clu_alloc_state(inode, lblk: end);
1865	if (ret < `0`)
1866	return ret;
1867	if (ret > `0`) {
1868	resv_clu--;
1869	end_allocated = (ret == `2`);
1870	}
1871	}
1872
1873	if (resv_clu) {
1874	ret = ext4_da_reserve_space(inode, nr_resv: resv_clu);
1875	if (ret != `0`) / ENOSPC /
1876	return ret;
1877	}
1878	}
1879
1880	ext4_es_insert_delayed_extent(inode, lblk, len, lclu_allocated,
1881	end_allocated);
1882	return `0`;
1883	}
1884
1885	/*
1886	* Looks up the requested blocks and sets the delalloc extent map.
1887	* First try to look up for the extent entry that contains the requested
1888	* blocks in the extent status tree without i_data_sem, then try to look
1889	* up for the ondisk extent mapping with i_data_sem in read mode,
1890	* finally hold i_data_sem in write mode, looks up again and add a
1891	* delalloc extent entry if it still couldn't find any extent. Pass out
1892	* the mapped extent through @map and return 0 on success.
1893	*/
1894	static int ext4_da_map_blocks(struct inode inode, struct* ext4_map_blocks *map)
1895	{
1896	struct extent_status es;
1897	int retval;
1898	#ifdef ES_AGGRESSIVE_TEST
1899	struct ext4_map_blocks orig_map;
1900
1901	memcpy(&orig_map, map, sizeof(*map));
1902	#endif
1903
1904	map->m_flags = `0`;
1905	ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1906	(unsigned long) map->m_lblk);
1907
1908	ext4_check_map_extents_env(inode);
1909
1910	/ Lookup extent status tree firstly /
1911	if (ext4_es_lookup_extent(inode, lblk: map->m_lblk, NULL, es: &es)) {
1912	map->m_len = min_t(unsigned int, map->m_len,
1913	es.es_len - (map->m_lblk - es.es_lblk));
1914
1915	if (ext4_es_is_hole(es: &es))
1916	goto add_delayed;
1917
1918	found:
1919	/*
1920	* Delayed extent could be allocated by fallocate.
1921	* So we need to check it.
1922	*/
1923	if (ext4_es_is_delayed(es: &es)) {
1924	map->m_flags \|= EXT4_MAP_DELAYED;
1925	return `0`;
1926	}
1927
1928	map->m_pblk = ext4_es_pblock(es: &es) + map->m_lblk - es.es_lblk;
1929	if (ext4_es_is_written(es: &es))
1930	map->m_flags \|= EXT4_MAP_MAPPED;
1931	else if (ext4_es_is_unwritten(es: &es))
1932	map->m_flags \|= EXT4_MAP_UNWRITTEN;
1933	else
1934	BUG();
1935
1936	#ifdef ES_AGGRESSIVE_TEST
1937	ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, `0`);
1938	#endif
1939	return `0`;
1940	}
1941
1942	/*
1943	* Try to see if we can get the block without requesting a new
1944	* file system block.
1945	*/
1946	down_read(sem: &EXT4_I(inode)->i_data_sem);
1947	if (ext4_has_inline_data(inode))
1948	retval = `0`;
1949	else
1950	retval = ext4_map_query_blocks(NULL, inode, map, flags: `0`);
1951	up_read(sem: &EXT4_I(inode)->i_data_sem);
1952	if (retval)
1953	return retval < `0` ? retval : `0`;
1954
1955	add_delayed:
1956	down_write(sem: &EXT4_I(inode)->i_data_sem);
1957	/*
1958	* Page fault path (ext4_page_mkwrite does not take i_rwsem)
1959	* and fallocate path (no folio lock) can race. Make sure we
1960	* lookup the extent status tree here again while i_data_sem
1961	* is held in write mode, before inserting a new da entry in
1962	* the extent status tree.
1963	*/
1964	if (ext4_es_lookup_extent(inode, lblk: map->m_lblk, NULL, es: &es)) {
1965	map->m_len = min_t(unsigned int, map->m_len,
1966	es.es_len - (map->m_lblk - es.es_lblk));
1967
1968	if (!ext4_es_is_hole(es: &es)) {
1969	up_write(sem: &EXT4_I(inode)->i_data_sem);
1970	goto found;
1971	}
1972	} else if (!ext4_has_inline_data(inode)) {
1973	retval = ext4_map_query_blocks(NULL, inode, map, flags: `0`);
1974	if (retval) {
1975	up_write(sem: &EXT4_I(inode)->i_data_sem);
1976	return retval < `0` ? retval : `0`;
1977	}
1978	}
1979
1980	map->m_flags \|= EXT4_MAP_DELAYED;
1981	retval = ext4_insert_delayed_blocks(inode, lblk: map->m_lblk, len: map->m_len);
1982	up_write(sem: &EXT4_I(inode)->i_data_sem);
1983
1984	return retval;
1985	}
1986
1987	/*
1988	* This is a special get_block_t callback which is used by
1989	* ext4_da_write_begin(). It will either return mapped block or
1990	* reserve space for a single block.
1991	*
1992	* For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1993	* We also have b_blocknr = -1 and b_bdev initialized properly
1994	*
1995	* For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1996	* We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1997	* initialized properly.
1998	*/
1999	int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
2000	struct buffer_head bh, int* create)
2001	{
2002	struct ext4_map_blocks map;
2003	sector_t invalid_block = ~((sector_t) `0xffff`);
2004	int ret = `0`;
2005
2006	BUG_ON(create == `0`);
2007	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
2008
2009	if (invalid_block < ext4_blocks_count(es: EXT4_SB(sb: inode->i_sb)->s_es))
2010	invalid_block = ~`0`;
2011
2012	map.m_lblk = iblock;
2013	map.m_len = `1`;
2014
2015	/*
2016	* first, we need to know whether the block is allocated already
2017	* preallocated blocks are unmapped but should treated
2018	* the same as allocated blocks.
2019	*/
2020	ret = ext4_da_map_blocks(inode, map: &map);
2021	if (ret < `0`)
2022	return ret;
2023
2024	if (map.m_flags & EXT4_MAP_DELAYED) {
2025	map_bh(bh, sb: inode->i_sb, block: invalid_block);
2026	set_buffer_new(bh);
2027	set_buffer_delay(bh);
2028	return `0`;
2029	}
2030
2031	map_bh(bh, sb: inode->i_sb, block: map.m_pblk);
2032	ext4_update_bh_state(bh, flags: map.m_flags);
2033
2034	if (buffer_unwritten(bh)) {
2035	/ A delayed write to unwritten bh should be marked*
2036	* new and mapped. Mapped ensures that we don't do
2037	* get_block multiple times when we write to the same
2038	* offset and new ensures that we do proper zero out
2039	* for partial write.
2040	*/
2041	set_buffer_new(bh);
2042	set_buffer_mapped(bh);
2043	}
2044	return `0`;
2045	}
2046
2047	static void mpage_folio_done(struct mpage_da_data mpd, struct* folio *folio)
2048	{
2049	mpd->start_pos += folio_size(folio);
2050	mpd->wbc->nr_to_write -= folio_nr_pages(folio);
2051	folio_unlock(folio);
2052	}
2053
2054	static int mpage_submit_folio(struct mpage_da_data mpd, struct* folio *folio)
2055	{
2056	size_t len;
2057	loff_t size;
2058	int err;
2059
2060	WARN_ON_ONCE(folio_pos(folio) != mpd->start_pos);
2061	folio_clear_dirty_for_io(folio);
2062	/*
2063	* We have to be very careful here! Nothing protects writeback path
2064	* against i_size changes and the page can be writeably mapped into
2065	* page tables. So an application can be growing i_size and writing
2066	* data through mmap while writeback runs. folio_clear_dirty_for_io()
2067	* write-protects our page in page tables and the page cannot get
2068	* written to again until we release folio lock. So only after
2069	* folio_clear_dirty_for_io() we are safe to sample i_size for
2070	* ext4_bio_write_folio() to zero-out tail of the written page. We rely
2071	* on the barrier provided by folio_test_clear_dirty() in
2072	* folio_clear_dirty_for_io() to make sure i_size is really sampled only
2073	* after page tables are updated.
2074	*/
2075	size = i_size_read(inode: mpd->inode);
2076	len = folio_size(folio);
2077	if (folio_pos(folio) + len > size &&
2078	!ext4_verity_in_progress(inode: mpd->inode))
2079	len = size & (len - `1`);
2080	err = ext4_bio_write_folio(io: &mpd->io_submit, page: folio, len);
2081
2082	return err;
2083	}
2084
2085	#define BH_FLAGS (BIT(BH_Unwritten) \| BIT(BH_Delay))
2086
2087	/*
2088	* mballoc gives us at most this number of blocks...
2089	* XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2090	* The rest of mballoc seems to handle chunks up to full group size.
2091	*/
2092	#define MAX_WRITEPAGES_EXTENT_LEN 2048
2093
2094	/*
2095	* mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2096	*
2097	* @mpd - extent of blocks
2098	* @lblk - logical number of the block in the file
2099	* @bh - buffer head we want to add to the extent
2100	*
2101	* The function is used to collect contig. blocks in the same state. If the
2102	* buffer doesn't require mapping for writeback and we haven't started the
2103	* extent of buffers to map yet, the function returns 'true' immediately - the
2104	* caller can write the buffer right away. Otherwise the function returns true
2105	* if the block has been added to the extent, false if the block couldn't be
2106	* added.
2107	*/
2108	static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2109	struct buffer_head *bh)
2110	{
2111	struct ext4_map_blocks *map = &mpd->map;
2112
2113	/ Buffer that doesn't need mapping for writeback? /
2114	if (!buffer_dirty(bh) \|\| !buffer_mapped(bh) \|\|
2115	(!buffer_delay(bh) && !buffer_unwritten(bh))) {
2116	/ So far no extent to map => we write the buffer right away /
2117	if (map->m_len == `0`)
2118	return true;
2119	return false;
2120	}
2121
2122	/ First block in the extent? /
2123	if (map->m_len == `0`) {
2124	/ We cannot map unless handle is started... /
2125	if (!mpd->do_map)
2126	return false;
2127	map->m_lblk = lblk;
2128	map->m_len = `1`;
2129	map->m_flags = bh->b_state & BH_FLAGS;
2130	return true;
2131	}
2132
2133	/ Don't go larger than mballoc is willing to allocate /
2134	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2135	return false;
2136
2137	/ Can we merge the block to our big extent? /
2138	if (lblk == map->m_lblk + map->m_len &&
2139	(bh->b_state & BH_FLAGS) == map->m_flags) {
2140	map->m_len++;
2141	return true;
2142	}
2143	return false;
2144	}
2145
2146	/*
2147	* mpage_process_page_bufs - submit page buffers for IO or add them to extent
2148	*
2149	* @mpd - extent of blocks for mapping
2150	* @head - the first buffer in the page
2151	* @bh - buffer we should start processing from
2152	* @lblk - logical number of the block in the file corresponding to @bh
2153	*
2154	* Walk through page buffers from @bh upto @head (exclusive) and either submit
2155	* the page for IO if all buffers in this page were mapped and there's no
2156	* accumulated extent of buffers to map or add buffers in the page to the
2157	* extent of buffers to map. The function returns 1 if the caller can continue
2158	* by processing the next page, 0 if it should stop adding buffers to the
2159	* extent to map because we cannot extend it anymore. It can also return value
2160	* < 0 in case of error during IO submission.
2161	*/
2162	static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2163	struct buffer_head *head,
2164	struct buffer_head *bh,
2165	ext4_lblk_t lblk)
2166	{
2167	struct inode *inode = mpd->inode;
2168	int err;
2169	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(node: inode) - `1`)
2170	>> inode->i_blkbits;
2171
2172	if (ext4_verity_in_progress(inode))
2173	blocks = EXT_MAX_BLOCKS;
2174
2175	do {
2176	BUG_ON(buffer_locked(bh));
2177
2178	if (lblk >= blocks \|\| !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2179	/ Found extent to map? /
2180	if (mpd->map.m_len)
2181	return `0`;
2182	/ Buffer needs mapping and handle is not started? /
2183	if (!mpd->do_map)
2184	return `0`;
2185	/ Everything mapped so far and we hit EOF /
2186	break;
2187	}
2188	} while (lblk++, (bh = bh->b_this_page) != head);
2189	/ So far everything mapped? Submit the page for IO. /
2190	if (mpd->map.m_len == `0`) {
2191	err = mpage_submit_folio(mpd, folio: head->b_folio);
2192	if (err < `0`)
2193	return err;
2194	mpage_folio_done(mpd, folio: head->b_folio);
2195	}
2196	if (lblk >= blocks) {
2197	mpd->scanned_until_end = `1`;
2198	return `0`;
2199	}
2200	return `1`;
2201	}
2202
2203	/*
2204	* mpage_process_folio - update folio buffers corresponding to changed extent
2205	* and may submit fully mapped page for IO
2206	* @mpd: description of extent to map, on return next extent to map
2207	* @folio: Contains these buffers.
2208	* @m_lblk: logical block mapping.
2209	* @m_pblk: corresponding physical mapping.
2210	* @map_bh: determines on return whether this page requires any further
2211	* mapping or not.
2212	*
2213	* Scan given folio buffers corresponding to changed extent and update buffer
2214	* state according to new extent state.
2215	* We map delalloc buffers to their physical location, clear unwritten bits.
2216	* If the given folio is not fully mapped, we update @mpd to the next extent in
2217	* the given folio that needs mapping & return @map_bh as true.
2218	*/
2219	static int mpage_process_folio(struct mpage_da_data mpd, struct* folio *folio,
2220	ext4_lblk_t m_lblk, ext4_fsblk_t m_pblk,
2221	bool *map_bh)
2222	{
2223	struct buffer_head head, bh;
2224	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2225	ext4_lblk_t lblk = *m_lblk;
2226	ext4_fsblk_t pblock = *m_pblk;
2227	int err = `0`;
2228	int blkbits = mpd->inode->i_blkbits;
2229	ssize_t io_end_size = `0`;
2230	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2231
2232	bh = head = folio_buffers(folio);
2233	do {
2234	if (lblk < mpd->map.m_lblk)
2235	continue;
2236	if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2237	/*
2238	* Buffer after end of mapped extent.
2239	* Find next buffer in the folio to map.
2240	*/
2241	mpd->map.m_len = `0`;
2242	mpd->map.m_flags = `0`;
2243	io_end_vec->size += io_end_size;
2244
2245	err = mpage_process_page_bufs(mpd, head, bh, lblk);
2246	if (err > `0`)
2247	err = `0`;
2248	if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2249	io_end_vec = ext4_alloc_io_end_vec(io_end);
2250	if (IS_ERR(ptr: io_end_vec)) {
2251	err = PTR_ERR(ptr: io_end_vec);
2252	goto out;
2253	}
2254	io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2255	}
2256	*map_bh = true;
2257	goto out;
2258	}
2259	if (buffer_delay(bh)) {
2260	clear_buffer_delay(bh);
2261	bh->b_blocknr = pblock++;
2262	}
2263	clear_buffer_unwritten(bh);
2264	io_end_size += (`1` << blkbits);
2265	} while (lblk++, (bh = bh->b_this_page) != head);
2266
2267	io_end_vec->size += io_end_size;
2268	*map_bh = false;
2269	out:
2270	*m_lblk = lblk;
2271	*m_pblk = pblock;
2272	return err;
2273	}
2274
2275	/*
2276	* mpage_map_buffers - update buffers corresponding to changed extent and
2277	* submit fully mapped pages for IO
2278	*
2279	* @mpd - description of extent to map, on return next extent to map
2280	*
2281	* Scan buffers corresponding to changed extent (we expect corresponding pages
2282	* to be already locked) and update buffer state according to new extent state.
2283	* We map delalloc buffers to their physical location, clear unwritten bits,
2284	* and mark buffers as uninit when we perform writes to unwritten extents
2285	* and do extent conversion after IO is finished. If the last page is not fully
2286	* mapped, we update @map to the next extent in the last page that needs
2287	* mapping. Otherwise we submit the page for IO.
2288	*/
2289	static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2290	{
2291	struct folio_batch fbatch;
2292	unsigned nr, i;
2293	struct inode *inode = mpd->inode;
2294	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2295	pgoff_t start, end;
2296	ext4_lblk_t lblk;
2297	ext4_fsblk_t pblock;
2298	int err;
2299	bool map_bh = false;
2300
2301	start = mpd->map.m_lblk >> bpp_bits;
2302	end = (mpd->map.m_lblk + mpd->map.m_len - `1`) >> bpp_bits;
2303	pblock = mpd->map.m_pblk;
2304
2305	folio_batch_init(fbatch: &fbatch);
2306	while (start <= end) {
2307	nr = filemap_get_folios(mapping: inode->i_mapping, start: &start, end, fbatch: &fbatch);
2308	if (nr == `0`)
2309	break;
2310	for (i = `0`; i < nr; i++) {
2311	struct folio *folio = fbatch.folios[i];
2312
2313	lblk = folio->index << bpp_bits;
2314	err = mpage_process_folio(mpd, folio, m_lblk: &lblk, m_pblk: &pblock,
2315	map_bh: &map_bh);
2316	/*
2317	* If map_bh is true, means page may require further bh
2318	* mapping, or maybe the page was submitted for IO.
2319	* So we return to call further extent mapping.
2320	*/
2321	if (err < `0` \|\| map_bh)
2322	goto out;
2323	/ Page fully mapped - let IO run! /
2324	err = mpage_submit_folio(mpd, folio);
2325	if (err < `0`)
2326	goto out;
2327	mpage_folio_done(mpd, folio);
2328	}
2329	folio_batch_release(fbatch: &fbatch);
2330	}
2331	/ Extent fully mapped and matches with page boundary. We are done. /
2332	mpd->map.m_len = `0`;
2333	mpd->map.m_flags = `0`;
2334	return `0`;
2335	out:
2336	folio_batch_release(fbatch: &fbatch);
2337	return err;
2338	}
2339
2340	static int mpage_map_one_extent(handle_t handle, struct* mpage_da_data *mpd)
2341	{
2342	struct inode *inode = mpd->inode;
2343	struct ext4_map_blocks *map = &mpd->map;
2344	int get_blocks_flags;
2345	int err, dioread_nolock;
2346
2347	/ Make sure transaction has enough credits for this extent /
2348	err = ext4_journal_ensure_extent_credits(handle, inode);
2349	if (err < `0`)
2350	return err;
2351
2352	trace_ext4_da_write_pages_extent(inode, map);
2353	/*
2354	* Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2355	* to convert an unwritten extent to be initialized (in the case
2356	* where we have written into one or more preallocated blocks). It is
2357	* possible that we're going to need more metadata blocks than
2358	* previously reserved. However we must not fail because we're in
2359	* writeback and there is nothing we can do about it so it might result
2360	* in data loss. So use reserved blocks to allocate metadata if
2361	* possible. In addition, do not cache any unrelated extents, as it
2362	* only holds the folio lock but does not hold the i_rwsem or
2363	* invalidate_lock, which could corrupt the extent status tree.
2364	*/
2365	get_blocks_flags = EXT4_GET_BLOCKS_CREATE \|
2366	EXT4_GET_BLOCKS_METADATA_NOFAIL \|
2367	EXT4_GET_BLOCKS_IO_SUBMIT \|
2368	EXT4_EX_NOCACHE;
2369
2370	dioread_nolock = ext4_should_dioread_nolock(inode);
2371	if (dioread_nolock)
2372	get_blocks_flags \|= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2373
2374	err = ext4_map_blocks(handle, inode, map, flags: get_blocks_flags);
2375	if (err < `0`)
2376	return err;
2377	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2378	if (!mpd->io_submit.io_end->handle &&
2379	ext4_handle_valid(handle)) {
2380	mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2381	handle->h_rsv_handle = NULL;
2382	}
2383	ext4_set_io_unwritten_flag(io_end: mpd->io_submit.io_end);
2384	}
2385
2386	BUG_ON(map->m_len == `0`);
2387	return `0`;
2388	}
2389
2390	/*
2391	* This is used to submit mapped buffers in a single folio that is not fully
2392	* mapped for various reasons, such as insufficient space or journal credits.
2393	*/
2394	static int mpage_submit_partial_folio(struct mpage_da_data *mpd)
2395	{
2396	struct inode *inode = mpd->inode;
2397	struct folio *folio;
2398	loff_t pos;
2399	int ret;
2400
2401	folio = filemap_get_folio(mapping: inode->i_mapping,
2402	index: mpd->start_pos >> PAGE_SHIFT);
2403	if (IS_ERR(ptr: folio))
2404	return PTR_ERR(ptr: folio);
2405	/*
2406	* The mapped position should be within the current processing folio
2407	* but must not be the folio start position.
2408	*/
2409	pos = ((loff_t)mpd->map.m_lblk) << inode->i_blkbits;
2410	if (WARN_ON_ONCE((folio_pos(folio) == pos) \|\|
2411	!folio_contains(folio, pos >> PAGE_SHIFT)))
2412	return -EINVAL;
2413
2414	ret = mpage_submit_folio(mpd, folio);
2415	if (ret)
2416	goto out;
2417	/*
2418	* Update start_pos to prevent this folio from being released in
2419	* mpage_release_unused_pages(), it will be reset to the aligned folio
2420	* pos when this folio is written again in the next round. Additionally,
2421	* do not update wbc->nr_to_write here, as it will be updated once the
2422	* entire folio has finished processing.
2423	*/
2424	mpd->start_pos = pos;
2425	out:
2426	folio_unlock(folio);
2427	folio_put(folio);
2428	return ret;
2429	}
2430
2431	/*
2432	* mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2433	* mpd->len and submit pages underlying it for IO
2434	*
2435	* @handle - handle for journal operations
2436	* @mpd - extent to map
2437	* @give_up_on_write - we set this to true iff there is a fatal error and there
2438	* is no hope of writing the data. The caller should discard
2439	* dirty pages to avoid infinite loops.
2440	*
2441	* The function maps extent starting at mpd->lblk of length mpd->len. If it is
2442	* delayed, blocks are allocated, if it is unwritten, we may need to convert
2443	* them to initialized or split the described range from larger unwritten
2444	* extent. Note that we need not map all the described range since allocation
2445	* can return less blocks or the range is covered by more unwritten extents. We
2446	* cannot map more because we are limited by reserved transaction credits. On
2447	* the other hand we always make sure that the last touched page is fully
2448	* mapped so that it can be written out (and thus forward progress is
2449	* guaranteed). After mapping we submit all mapped pages for IO.
2450	*/
2451	static int mpage_map_and_submit_extent(handle_t *handle,
2452	struct mpage_da_data *mpd,
2453	bool *give_up_on_write)
2454	{
2455	struct inode *inode = mpd->inode;
2456	struct ext4_map_blocks *map = &mpd->map;
2457	int err;
2458	loff_t disksize;
2459	int progress = `0`;
2460	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2461	struct ext4_io_end_vec *io_end_vec;
2462
2463	io_end_vec = ext4_alloc_io_end_vec(io_end);
2464	if (IS_ERR(ptr: io_end_vec))
2465	return PTR_ERR(ptr: io_end_vec);
2466	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2467	do {
2468	err = mpage_map_one_extent(handle, mpd);
2469	if (err < `0`) {
2470	struct super_block *sb = inode->i_sb;
2471
2472	if (ext4_emergency_state(sb))
2473	goto invalidate_dirty_pages;
2474	/*
2475	* Let the uper layers retry transient errors.
2476	* In the case of ENOSPC, if ext4_count_free_blocks()
2477	* is non-zero, a commit should free up blocks.
2478	*/
2479	if ((err == -ENOMEM) \|\| (err == -EAGAIN) \|\|
2480	(err == -ENOSPC && ext4_count_free_clusters(sb))) {
2481	/*
2482	* We may have already allocated extents for
2483	* some bhs inside the folio, issue the
2484	* corresponding data to prevent stale data.
2485	*/
2486	if (progress) {
2487	if (mpage_submit_partial_folio(mpd))
2488	goto invalidate_dirty_pages;
2489	goto update_disksize;
2490	}
2491	return err;
2492	}
2493	ext4_msg(sb, KERN_CRIT,
2494	"Delayed block allocation failed for "
2495	"inode %lu at logical offset %llu with"
2496	" max blocks %u with error %d",
2497	inode->i_ino,
2498	(unsigned long long)map->m_lblk,
2499	(unsigned)map->m_len, -err);
2500	ext4_msg(sb, KERN_CRIT,
2501	"This should not happen!! Data will "
2502	"be lost\n");
2503	if (err == -ENOSPC)
2504	ext4_print_free_blocks(inode);
2505	invalidate_dirty_pages:
2506	*give_up_on_write = true;
2507	return err;
2508	}
2509	progress = `1`;
2510	/*
2511	* Update buffer state, submit mapped pages, and get us new
2512	* extent to map
2513	*/
2514	err = mpage_map_and_submit_buffers(mpd);
2515	if (err < `0`)
2516	goto update_disksize;
2517	} while (map->m_len);
2518
2519	update_disksize:
2520	/*
2521	* Update on-disk size after IO is submitted. Races with
2522	* truncate are avoided by checking i_size under i_data_sem.
2523	*/
2524	disksize = mpd->start_pos;
2525	if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2526	int err2;
2527	loff_t i_size;
2528
2529	down_write(sem: &EXT4_I(inode)->i_data_sem);
2530	i_size = i_size_read(inode);
2531	if (disksize > i_size)
2532	disksize = i_size;
2533	if (disksize > EXT4_I(inode)->i_disksize)
2534	EXT4_I(inode)->i_disksize = disksize;
2535	up_write(sem: &EXT4_I(inode)->i_data_sem);
2536	err2 = ext4_mark_inode_dirty(handle, inode);
2537	if (err2) {
2538	ext4_error_err(inode->i_sb, -err2,
2539	"Failed to mark inode %lu dirty",
2540	inode->i_ino);
2541	}
2542	if (!err)
2543	err = err2;
2544	}
2545	return err;
2546	}
2547
2548	static int ext4_journal_folio_buffers(handle_t handle, struct* folio *folio,
2549	size_t len)
2550	{
2551	struct buffer_head *page_bufs = folio_buffers(folio);
2552	struct inode *inode = folio->mapping->host;
2553	int ret, err;
2554
2555	ret = ext4_walk_page_buffers(handle, inode, head: page_bufs, from: `0`, to: len,
2556	NULL, fn: do_journal_get_write_access);
2557	err = ext4_walk_page_buffers(handle, inode, head: page_bufs, from: `0`, to: len,
2558	NULL, fn: write_end_fn);
2559	if (ret == `0`)
2560	ret = err;
2561	err = ext4_jbd2_inode_add_write(handle, inode, start_byte: folio_pos(folio), length: len);
2562	if (ret == `0`)
2563	ret = err;
2564	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
2565
2566	return ret;
2567	}
2568
2569	static int mpage_journal_page_buffers(handle_t *handle,
2570	struct mpage_da_data *mpd,
2571	struct folio *folio)
2572	{
2573	struct inode *inode = mpd->inode;
2574	loff_t size = i_size_read(inode);
2575	size_t len = folio_size(folio);
2576
2577	folio_clear_checked(folio);
2578	mpd->wbc->nr_to_write -= folio_nr_pages(folio);
2579
2580	if (folio_pos(folio) + len > size &&
2581	!ext4_verity_in_progress(inode))
2582	len = size & (len - `1`);
2583
2584	return ext4_journal_folio_buffers(handle, folio, len);
2585	}
2586
2587	/*
2588	* mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2589	* needing mapping, submit mapped pages
2590	*
2591	* @mpd - where to look for pages
2592	*
2593	* Walk dirty pages in the mapping. If they are fully mapped, submit them for
2594	* IO immediately. If we cannot map blocks, we submit just already mapped
2595	* buffers in the page for IO and keep page dirty. When we can map blocks and
2596	* we find a page which isn't mapped we start accumulating extent of buffers
2597	* underlying these pages that needs mapping (formed by either delayed or
2598	* unwritten buffers). We also lock the pages containing these buffers. The
2599	* extent found is returned in @mpd structure (starting at mpd->lblk with
2600	* length mpd->len blocks).
2601	*
2602	* Note that this function can attach bios to one io_end structure which are
2603	* neither logically nor physically contiguous. Although it may seem as an
2604	* unnecessary complication, it is actually inevitable in blocksize < pagesize
2605	* case as we need to track IO to all buffers underlying a page in one io_end.
2606	*/
2607	static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2608	{
2609	struct address_space *mapping = mpd->inode->i_mapping;
2610	struct folio_batch fbatch;
2611	unsigned int nr_folios;
2612	pgoff_t index = mpd->start_pos >> PAGE_SHIFT;
2613	pgoff_t end = mpd->end_pos >> PAGE_SHIFT;
2614	xa_mark_t tag;
2615	int i, err = `0`;
2616	int blkbits = mpd->inode->i_blkbits;
2617	ext4_lblk_t lblk;
2618	struct buffer_head *head;
2619	handle_t *handle = NULL;
2620	int bpp = ext4_journal_blocks_per_folio(inode: mpd->inode);
2621
2622	if (mpd->wbc->sync_mode == WB_SYNC_ALL \|\| mpd->wbc->tagged_writepages)
2623	tag = PAGECACHE_TAG_TOWRITE;
2624	else
2625	tag = PAGECACHE_TAG_DIRTY;
2626
2627	mpd->map.m_len = `0`;
2628	mpd->next_pos = mpd->start_pos;
2629	if (ext4_should_journal_data(inode: mpd->inode)) {
2630	handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,
2631	bpp);
2632	if (IS_ERR(ptr: handle))
2633	return PTR_ERR(ptr: handle);
2634	}
2635	folio_batch_init(fbatch: &fbatch);
2636	while (index <= end) {
2637	nr_folios = filemap_get_folios_tag(mapping, start: &index, end,
2638	tag, fbatch: &fbatch);
2639	if (nr_folios == `0`)
2640	break;
2641
2642	for (i = `0`; i < nr_folios; i++) {
2643	struct folio *folio = fbatch.folios[i];
2644
2645	/*
2646	* Accumulated enough dirty pages? This doesn't apply
2647	* to WB_SYNC_ALL mode. For integrity sync we have to
2648	* keep going because someone may be concurrently
2649	* dirtying pages, and we might have synced a lot of
2650	* newly appeared dirty pages, but have not synced all
2651	* of the old dirty pages.
2652	*/
2653	if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
2654	mpd->wbc->nr_to_write <=
2655	mpd->map.m_len >> (PAGE_SHIFT - blkbits))
2656	goto out;
2657
2658	/ If we can't merge this page, we are done. /
2659	if (mpd->map.m_len > `0` &&
2660	mpd->next_pos != folio_pos(folio))
2661	goto out;
2662
2663	if (handle) {
2664	err = ext4_journal_ensure_credits(handle, credits: bpp,
2665	revoke_creds: `0`);
2666	if (err < `0`)
2667	goto out;
2668	}
2669
2670	folio_lock(folio);
2671	/*
2672	* If the page is no longer dirty, or its mapping no
2673	* longer corresponds to inode we are writing (which
2674	* means it has been truncated or invalidated), or the
2675	* page is already under writeback and we are not doing
2676	* a data integrity writeback, skip the page
2677	*/
2678	if (!folio_test_dirty(folio) \|\|
2679	(folio_test_writeback(folio) &&
2680	(mpd->wbc->sync_mode == WB_SYNC_NONE)) \|\|
2681	unlikely(folio->mapping != mapping)) {
2682	folio_unlock(folio);
2683	continue;
2684	}
2685
2686	folio_wait_writeback(folio);
2687	BUG_ON(folio_test_writeback(folio));
2688
2689	/*
2690	* Should never happen but for buggy code in
2691	* other subsystems that call
2692	* set_page_dirty() without properly warning
2693	* the file system first. See [1] for more
2694	* information.
2695	*
2696	* [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
2697	*/
2698	if (!folio_buffers(folio)) {
2699	ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", folio->index);
2700	folio_clear_dirty(folio);
2701	folio_unlock(folio);
2702	continue;
2703	}
2704
2705	if (mpd->map.m_len == `0`)
2706	mpd->start_pos = folio_pos(folio);
2707	mpd->next_pos = folio_pos(folio) + folio_size(folio);
2708	/*
2709	* Writeout when we cannot modify metadata is simple.
2710	* Just submit the page. For data=journal mode we
2711	* first handle writeout of the page for checkpoint and
2712	* only after that handle delayed page dirtying. This
2713	* makes sure current data is checkpointed to the final
2714	* location before possibly journalling it again which
2715	* is desirable when the page is frequently dirtied
2716	* through a pin.
2717	*/
2718	if (!mpd->can_map) {
2719	err = mpage_submit_folio(mpd, folio);
2720	if (err < `0`)
2721	goto out;
2722	/ Pending dirtying of journalled data? /
2723	if (folio_test_checked(folio)) {
2724	err = mpage_journal_page_buffers(handle,
2725	mpd, folio);
2726	if (err < `0`)
2727	goto out;
2728	mpd->journalled_more_data = `1`;
2729	}
2730	mpage_folio_done(mpd, folio);
2731	} else {
2732	/ Add all dirty buffers to mpd /
2733	lblk = ((ext4_lblk_t)folio->index) <<
2734	(PAGE_SHIFT - blkbits);
2735	head = folio_buffers(folio);
2736	err = mpage_process_page_bufs(mpd, head, bh: head,
2737	lblk);
2738	if (err <= `0`)
2739	goto out;
2740	err = `0`;
2741	}
2742	}
2743	folio_batch_release(fbatch: &fbatch);
2744	cond_resched();
2745	}
2746	mpd->scanned_until_end = `1`;
2747	if (handle)
2748	ext4_journal_stop(handle);
2749	return `0`;
2750	out:
2751	folio_batch_release(fbatch: &fbatch);
2752	if (handle)
2753	ext4_journal_stop(handle);
2754	return err;
2755	}
2756
2757	static int ext4_do_writepages(struct mpage_da_data *mpd)
2758	{
2759	struct writeback_control *wbc = mpd->wbc;
2760	pgoff_t writeback_index = `0`;
2761	long nr_to_write = wbc->nr_to_write;
2762	int range_whole = `0`;
2763	int cycled = `1`;
2764	handle_t *handle = NULL;
2765	struct inode *inode = mpd->inode;
2766	struct address_space *mapping = inode->i_mapping;
2767	int needed_blocks, rsv_blocks = `0`, ret = `0`;
2768	struct ext4_sb_info *sbi = EXT4_SB(sb: mapping->host->i_sb);
2769	struct blk_plug plug;
2770	bool give_up_on_write = false;
2771
2772	trace_ext4_writepages(inode, wbc);
2773
2774	/*
2775	* No pages to write? This is mainly a kludge to avoid starting
2776	* a transaction for special inodes like journal inode on last iput()
2777	* because that could violate lock ordering on umount
2778	*/
2779	if (!mapping->nrpages \|\| !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2780	goto out_writepages;
2781
2782	/*
2783	* If the filesystem has aborted, it is read-only, so return
2784	* right away instead of dumping stack traces later on that
2785	* will obscure the real source of the problem. We test
2786	* fs shutdown state instead of sb->s_flag's SB_RDONLY because
2787	* the latter could be true if the filesystem is mounted
2788	* read-only, and in that case, ext4_writepages should
2789	* never be called, so if that ever happens, we would want
2790	* the stack trace.
2791	*/
2792	ret = ext4_emergency_state(sb: mapping->host->i_sb);
2793	if (unlikely(ret))
2794	goto out_writepages;
2795
2796	/*
2797	* If we have inline data and arrive here, it means that
2798	* we will soon create the block for the 1st page, so
2799	* we'd better clear the inline data here.
2800	*/
2801	if (ext4_has_inline_data(inode)) {
2802	/ Just inode will be modified... /
2803	handle = ext4_journal_start(inode, EXT4_HT_INODE, `1`);
2804	if (IS_ERR(ptr: handle)) {
2805	ret = PTR_ERR(ptr: handle);
2806	goto out_writepages;
2807	}
2808	BUG_ON(ext4_test_inode_state(inode,
2809	EXT4_STATE_MAY_INLINE_DATA));
2810	ext4_destroy_inline_data(handle, inode);
2811	ext4_journal_stop(handle);
2812	}
2813
2814	/*
2815	* data=journal mode does not do delalloc so we just need to writeout /
2816	* journal already mapped buffers. On the other hand we need to commit
2817	* transaction to make data stable. We expect all the data to be
2818	* already in the journal (the only exception are DMA pinned pages
2819	* dirtied behind our back) so we commit transaction here and run the
2820	* writeback loop to checkpoint them. The checkpointing is not actually
2821	* necessary to make data persistent but quite a few places (extent
2822	* shifting operations, fsverity, ...) depend on being able to drop
2823	* pagecache pages after calling filemap_write_and_wait() and for that
2824	* checkpointing needs to happen.
2825	*/
2826	if (ext4_should_journal_data(inode)) {
2827	mpd->can_map = `0`;
2828	if (wbc->sync_mode == WB_SYNC_ALL)
2829	ext4_fc_commit(journal: sbi->s_journal,
2830	EXT4_I(inode)->i_datasync_tid);
2831	}
2832	mpd->journalled_more_data = `0`;
2833
2834	if (ext4_should_dioread_nolock(inode)) {
2835	int bpf = ext4_journal_blocks_per_folio(inode);
2836	/*
2837	* We may need to convert up to one extent per block in
2838	* the folio and we may dirty the inode.
2839	*/
2840	rsv_blocks = `1` + ext4_ext_index_trans_blocks(inode, extents: bpf);
2841	}
2842
2843	if (wbc->range_start == `0` && wbc->range_end == LLONG_MAX)
2844	range_whole = `1`;
2845
2846	if (wbc->range_cyclic) {
2847	writeback_index = mapping->writeback_index;
2848	if (writeback_index)
2849	cycled = `0`;
2850	mpd->start_pos = writeback_index << PAGE_SHIFT;
2851	mpd->end_pos = LLONG_MAX;
2852	} else {
2853	mpd->start_pos = wbc->range_start;
2854	mpd->end_pos = wbc->range_end;
2855	}
2856
2857	ext4_io_submit_init(io: &mpd->io_submit, wbc);
2858	retry:
2859	if (wbc->sync_mode == WB_SYNC_ALL \|\| wbc->tagged_writepages)
2860	tag_pages_for_writeback(mapping, start: mpd->start_pos >> PAGE_SHIFT,
2861	end: mpd->end_pos >> PAGE_SHIFT);
2862	blk_start_plug(&plug);
2863
2864	/*
2865	* First writeback pages that don't need mapping - we can avoid
2866	* starting a transaction unnecessarily and also avoid being blocked
2867	* in the block layer on device congestion while having transaction
2868	* started.
2869	*/
2870	mpd->do_map = `0`;
2871	mpd->scanned_until_end = `0`;
2872	mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2873	if (!mpd->io_submit.io_end) {
2874	ret = -ENOMEM;
2875	goto unplug;
2876	}
2877	ret = mpage_prepare_extent_to_map(mpd);
2878	/ Unlock pages we didn't use /
2879	mpage_release_unused_pages(mpd, invalidate: false);
2880	/ Submit prepared bio /
2881	ext4_io_submit(io: &mpd->io_submit);
2882	ext4_put_io_end_defer(io_end: mpd->io_submit.io_end);
2883	mpd->io_submit.io_end = NULL;
2884	if (ret < `0`)
2885	goto unplug;
2886
2887	while (!mpd->scanned_until_end && wbc->nr_to_write > `0`) {
2888	/ For each extent of pages we use new io_end /
2889	mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2890	if (!mpd->io_submit.io_end) {
2891	ret = -ENOMEM;
2892	break;
2893	}
2894
2895	WARN_ON_ONCE(!mpd->can_map);
2896	/*
2897	* We have two constraints: We find one extent to map and we
2898	* must always write out whole page (makes a difference when
2899	* blocksize < pagesize) so that we don't block on IO when we
2900	* try to write out the rest of the page. Journalled mode is
2901	* not supported by delalloc.
2902	*/
2903	BUG_ON(ext4_should_journal_data(inode));
2904	/*
2905	* Calculate the number of credits needed to reserve for one
2906	* extent of up to MAX_WRITEPAGES_EXTENT_LEN blocks. It will
2907	* attempt to extend the transaction or start a new iteration
2908	* if the reserved credits are insufficient.
2909	*/
2910	needed_blocks = ext4_chunk_trans_blocks(inode,
2911	MAX_WRITEPAGES_EXTENT_LEN);
2912	/ start a new transaction /
2913	handle = ext4_journal_start_with_reserve(inode,
2914	EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2915	if (IS_ERR(ptr: handle)) {
2916	ret = PTR_ERR(ptr: handle);
2917	ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2918	"%ld pages, ino %lu; err %d", __func__,
2919	wbc->nr_to_write, inode->i_ino, ret);
2920	/ Release allocated io_end /
2921	ext4_put_io_end(io_end: mpd->io_submit.io_end);
2922	mpd->io_submit.io_end = NULL;
2923	break;
2924	}
2925	mpd->do_map = `1`;
2926
2927	trace_ext4_da_write_folios_start(inode, start_pos: mpd->start_pos,
2928	next_pos: mpd->next_pos, wbc);
2929	ret = mpage_prepare_extent_to_map(mpd);
2930	if (!ret && mpd->map.m_len)
2931	ret = mpage_map_and_submit_extent(handle, mpd,
2932	give_up_on_write: &give_up_on_write);
2933	/*
2934	* Caution: If the handle is synchronous,
2935	* ext4_journal_stop() can wait for transaction commit
2936	* to finish which may depend on writeback of pages to
2937	* complete or on page lock to be released. In that
2938	* case, we have to wait until after we have
2939	* submitted all the IO, released page locks we hold,
2940	* and dropped io_end reference (for extent conversion
2941	* to be able to complete) before stopping the handle.
2942	*/
2943	if (!ext4_handle_valid(handle) \|\| handle->h_sync == `0`) {
2944	ext4_journal_stop(handle);
2945	handle = NULL;
2946	mpd->do_map = `0`;
2947	}
2948	/ Unlock pages we didn't use /
2949	mpage_release_unused_pages(mpd, invalidate: give_up_on_write);
2950	/ Submit prepared bio /
2951	ext4_io_submit(io: &mpd->io_submit);
2952
2953	/*
2954	* Drop our io_end reference we got from init. We have
2955	* to be careful and use deferred io_end finishing if
2956	* we are still holding the transaction as we can
2957	* release the last reference to io_end which may end
2958	* up doing unwritten extent conversion.
2959	*/
2960	if (handle) {
2961	ext4_put_io_end_defer(io_end: mpd->io_submit.io_end);
2962	ext4_journal_stop(handle);
2963	} else
2964	ext4_put_io_end(io_end: mpd->io_submit.io_end);
2965	mpd->io_submit.io_end = NULL;
2966	trace_ext4_da_write_folios_end(inode, start_pos: mpd->start_pos,
2967	next_pos: mpd->next_pos, wbc, ret);
2968
2969	if (ret == -ENOSPC && sbi->s_journal) {
2970	/*
2971	* Commit the transaction which would
2972	* free blocks released in the transaction
2973	* and try again
2974	*/
2975	jbd2_journal_force_commit_nested(sbi->s_journal);
2976	ret = `0`;
2977	continue;
2978	}
2979	if (ret == -EAGAIN)
2980	ret = `0`;
2981	/ Fatal error - ENOMEM, EIO... /
2982	if (ret)
2983	break;
2984	}
2985	unplug:
2986	blk_finish_plug(&plug);
2987	if (!ret && !cycled && wbc->nr_to_write > `0`) {
2988	cycled = `1`;
2989	mpd->end_pos = (writeback_index << PAGE_SHIFT) - `1`;
2990	mpd->start_pos = `0`;
2991	goto retry;
2992	}
2993
2994	/ Update index /
2995	if (wbc->range_cyclic \|\| (range_whole && wbc->nr_to_write > `0`))
2996	/*
2997	* Set the writeback_index so that range_cyclic
2998	* mode will write it back later
2999	*/
3000	mapping->writeback_index = mpd->start_pos >> PAGE_SHIFT;
3001
3002	out_writepages:
3003	trace_ext4_writepages_result(inode, wbc, ret,
3004	pages_written: nr_to_write - wbc->nr_to_write);
3005	return ret;
3006	}
3007
3008	static int ext4_writepages(struct address_space *mapping,
3009	struct writeback_control *wbc)
3010	{
3011	struct super_block *sb = mapping->host->i_sb;
3012	struct mpage_da_data mpd = {
3013	.inode = mapping->host,
3014	.wbc = wbc,
3015	.can_map = `1`,
3016	};
3017	int ret;
3018	int alloc_ctx;
3019
3020	ret = ext4_emergency_state(sb);
3021	if (unlikely(ret))
3022	return ret;
3023
3024	alloc_ctx = ext4_writepages_down_read(sb);
3025	ret = ext4_do_writepages(mpd: &mpd);
3026	/*
3027	* For data=journal writeback we could have come across pages marked
3028	* for delayed dirtying (PageChecked) which were just added to the
3029	* running transaction. Try once more to get them to stable storage.
3030	*/
3031	if (!ret && mpd.journalled_more_data)
3032	ret = ext4_do_writepages(mpd: &mpd);
3033	ext4_writepages_up_read(sb, ctx: alloc_ctx);
3034
3035	return ret;
3036	}
3037
3038	int ext4_normal_submit_inode_data_buffers(struct jbd2_inode *jinode)
3039	{
3040	struct writeback_control wbc = {
3041	.sync_mode = WB_SYNC_ALL,
3042	.nr_to_write = LONG_MAX,
3043	.range_start = jinode->i_dirty_start,
3044	.range_end = jinode->i_dirty_end,
3045	};
3046	struct mpage_da_data mpd = {
3047	.inode = jinode->i_vfs_inode,
3048	.wbc = &wbc,
3049	.can_map = `0`,
3050	};
3051	return ext4_do_writepages(mpd: &mpd);
3052	}
3053
3054	static int ext4_dax_writepages(struct address_space *mapping,
3055	struct writeback_control *wbc)
3056	{
3057	int ret;
3058	long nr_to_write = wbc->nr_to_write;
3059	struct inode *inode = mapping->host;
3060	int alloc_ctx;
3061
3062	ret = ext4_emergency_state(sb: inode->i_sb);
3063	if (unlikely(ret))
3064	return ret;
3065
3066	alloc_ctx = ext4_writepages_down_read(sb: inode->i_sb);
3067	trace_ext4_writepages(inode, wbc);
3068
3069	ret = dax_writeback_mapping_range(mapping,
3070	dax_dev: EXT4_SB(sb: inode->i_sb)->s_daxdev, wbc);
3071	trace_ext4_writepages_result(inode, wbc, ret,
3072	pages_written: nr_to_write - wbc->nr_to_write);
3073	ext4_writepages_up_read(sb: inode->i_sb, ctx: alloc_ctx);
3074	return ret;
3075	}
3076
3077	static int ext4_nonda_switch(struct super_block *sb)
3078	{
3079	s64 free_clusters, dirty_clusters;
3080	struct ext4_sb_info *sbi = EXT4_SB(sb);
3081
3082	/*
3083	* switch to non delalloc mode if we are running low
3084	* on free block. The free block accounting via percpu
3085	* counters can get slightly wrong with percpu_counter_batch getting
3086	* accumulated on each CPU without updating global counters
3087	* Delalloc need an accurate free block accounting. So switch
3088	* to non delalloc when we are near to error range.
3089	*/
3090	free_clusters =
3091	percpu_counter_read_positive(fbc: &sbi->s_freeclusters_counter);
3092	dirty_clusters =
3093	percpu_counter_read_positive(fbc: &sbi->s_dirtyclusters_counter);
3094	/*
3095	* Start pushing delalloc when 1/2 of free blocks are dirty.
3096	*/
3097	if (dirty_clusters && (free_clusters < `2` * dirty_clusters))
3098	try_to_writeback_inodes_sb(sb, reason: WB_REASON_FS_FREE_SPACE);
3099
3100	if (`2` * free_clusters < `3` * dirty_clusters \|\|
3101	free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
3102	/*
3103	* free block count is less than 150% of dirty blocks
3104	* or free blocks is less than watermark
3105	*/
3106	return `1`;
3107	}
3108	return `0`;
3109	}
3110
3111	static int ext4_da_write_begin(const struct kiocb *iocb,
3112	struct address_space *mapping,
3113	loff_t pos, unsigned len,
3114	struct folio *foliop, void* **fsdata)
3115	{
3116	int ret, retries = `0`;
3117	struct folio *folio;
3118	pgoff_t index;
3119	struct inode *inode = mapping->host;
3120
3121	ret = ext4_emergency_state(sb: inode->i_sb);
3122	if (unlikely(ret))
3123	return ret;
3124
3125	index = pos >> PAGE_SHIFT;
3126
3127	if (ext4_nonda_switch(sb: inode->i_sb) \|\| ext4_verity_in_progress(inode)) {
3128	fsdata = (void* *)FALL_BACK_TO_NONDELALLOC;
3129	return ext4_write_begin(iocb, mapping, pos,
3130	len, foliop, fsdata);
3131	}
3132	fsdata = (void* *)`0`;
3133	trace_ext4_da_write_begin(inode, pos, len);
3134
3135	if (ext4_test_inode_state(inode, bit: EXT4_STATE_MAY_INLINE_DATA)) {
3136	ret = ext4_generic_write_inline_data(mapping, inode, pos, len,
3137	foliop, fsdata, da: true);
3138	if (ret < `0`)
3139	return ret;
3140	if (ret == `1`)
3141	return `0`;
3142	}
3143
3144	retry:
3145	folio = write_begin_get_folio(iocb, mapping, index, len);
3146	if (IS_ERR(ptr: folio))
3147	return PTR_ERR(ptr: folio);
3148
3149	if (pos + len > folio_pos(folio) + folio_size(folio))
3150	len = folio_pos(folio) + folio_size(folio) - pos;
3151
3152	ret = ext4_block_write_begin(NULL, folio, pos, len,
3153	get_block: ext4_da_get_block_prep);
3154	if (ret < `0`) {
3155	folio_unlock(folio);
3156	folio_put(folio);
3157	/*
3158	* ext4_block_write_begin may have instantiated a few blocks
3159	* outside i_size. Trim these off again. Don't need
3160	* i_size_read because we hold inode lock.
3161	*/
3162	if (pos + len > inode->i_size)
3163	ext4_truncate_failed_write(inode);
3164
3165	if (ret == -ENOSPC &&
3166	ext4_should_retry_alloc(sb: inode->i_sb, retries: &retries))
3167	goto retry;
3168	return ret;
3169	}
3170
3171	*foliop = folio;
3172	return ret;
3173	}
3174
3175	/*
3176	* Check if we should update i_disksize
3177	* when write to the end of file but not require block allocation
3178	*/
3179	static int ext4_da_should_update_i_disksize(struct folio *folio,
3180	unsigned long offset)
3181	{
3182	struct buffer_head *bh;
3183	struct inode *inode = folio->mapping->host;
3184	unsigned int idx;
3185	int i;
3186
3187	bh = folio_buffers(folio);
3188	idx = offset >> inode->i_blkbits;
3189
3190	for (i = `0`; i < idx; i++)
3191	bh = bh->b_this_page;
3192
3193	if (!buffer_mapped(bh) \|\| (buffer_delay(bh)) \|\| buffer_unwritten(bh))
3194	return `0`;
3195	return `1`;
3196	}
3197
3198	static int ext4_da_do_write_end(struct address_space *mapping,
3199	loff_t pos, unsigned len, unsigned copied,
3200	struct folio *folio)
3201	{
3202	struct inode *inode = mapping->host;
3203	loff_t old_size = inode->i_size;
3204	bool disksize_changed = false;
3205	loff_t new_i_size, zero_len = `0`;
3206	handle_t *handle;
3207
3208	if (unlikely(!folio_buffers(folio))) {
3209	folio_unlock(folio);
3210	folio_put(folio);
3211	return -EIO;
3212	}
3213	/*
3214	* block_write_end() will mark the inode as dirty with I_DIRTY_PAGES
3215	* flag, which all that's needed to trigger page writeback.
3216	*/
3217	copied = block_write_end(pos, len, copied, folio);
3218	new_i_size = pos + copied;
3219
3220	/*
3221	* It's important to update i_size while still holding folio lock,
3222	* because folio writeout could otherwise come in and zero beyond
3223	* i_size.
3224	*
3225	* Since we are holding inode lock, we are sure i_disksize <=
3226	* i_size. We also know that if i_disksize < i_size, there are
3227	* delalloc writes pending in the range up to i_size. If the end of
3228	* the current write is <= i_size, there's no need to touch
3229	* i_disksize since writeback will push i_disksize up to i_size
3230	* eventually. If the end of the current write is > i_size and
3231	* inside an allocated block which ext4_da_should_update_i_disksize()
3232	* checked, we need to update i_disksize here as certain
3233	* ext4_writepages() paths not allocating blocks and update i_disksize.
3234	*/
3235	if (new_i_size > inode->i_size) {
3236	unsigned long end;
3237
3238	i_size_write(inode, i_size: new_i_size);
3239	end = offset_in_folio(folio, new_i_size - `1`);
3240	if (copied && ext4_da_should_update_i_disksize(folio, offset: end)) {
3241	ext4_update_i_disksize(inode, newsize: new_i_size);
3242	disksize_changed = true;
3243	}
3244	}
3245
3246	folio_unlock(folio);
3247	folio_put(folio);
3248
3249	if (pos > old_size) {
3250	pagecache_isize_extended(inode, from: old_size, to: pos);
3251	zero_len = pos - old_size;
3252	}
3253
3254	if (!disksize_changed && !zero_len)
3255	return copied;
3256
3257	handle = ext4_journal_start(inode, EXT4_HT_INODE, `2`);
3258	if (IS_ERR(ptr: handle))
3259	return PTR_ERR(ptr: handle);
3260	if (zero_len)
3261	ext4_zero_partial_blocks(handle, inode, lstart: old_size, lend: zero_len);
3262	ext4_mark_inode_dirty(handle, inode);
3263	ext4_journal_stop(handle);
3264
3265	return copied;
3266	}
3267
3268	static int ext4_da_write_end(const struct kiocb *iocb,
3269	struct address_space *mapping,
3270	loff_t pos, unsigned len, unsigned copied,
3271	struct folio folio, void* *fsdata)
3272	{
3273	struct inode *inode = mapping->host;
3274	int write_mode = (int)(unsigned long)fsdata;
3275
3276	if (write_mode == FALL_BACK_TO_NONDELALLOC)
3277	return ext4_write_end(iocb, mapping, pos,
3278	len, copied, folio, fsdata);
3279
3280	trace_ext4_da_write_end(inode, pos, len, copied);
3281
3282	if (write_mode != CONVERT_INLINE_DATA &&
3283	ext4_test_inode_state(inode, bit: EXT4_STATE_MAY_INLINE_DATA) &&
3284	ext4_has_inline_data(inode))
3285	return ext4_write_inline_data_end(inode, pos, len, copied,
3286	folio);
3287
3288	if (unlikely(copied < len) && !folio_test_uptodate(folio))
3289	copied = `0`;
3290
3291	return ext4_da_do_write_end(mapping, pos, len, copied, folio);
3292	}
3293
3294	/*
3295	* Force all delayed allocation blocks to be allocated for a given inode.
3296	*/
3297	int ext4_alloc_da_blocks(struct inode *inode)
3298	{
3299	trace_ext4_alloc_da_blocks(inode);
3300
3301	if (!EXT4_I(inode)->i_reserved_data_blocks)
3302	return `0`;
3303
3304	/*
3305	* We do something simple for now. The filemap_flush() will
3306	* also start triggering a write of the data blocks, which is
3307	* not strictly speaking necessary (and for users of
3308	* laptop_mode, not even desirable). However, to do otherwise
3309	* would require replicating code paths in:
3310	*
3311	* ext4_writepages() ->
3312	* write_cache_pages() ---> (via passed in callback function)
3313	* __mpage_da_writepage() -->
3314	* mpage_add_bh_to_extent()
3315	* mpage_da_map_blocks()
3316	*
3317	* The problem is that write_cache_pages(), located in
3318	* mm/page-writeback.c, marks pages clean in preparation for
3319	* doing I/O, which is not desirable if we're not planning on
3320	* doing I/O at all.
3321	*
3322	* We could call write_cache_pages(), and then redirty all of
3323	* the pages by calling redirty_page_for_writepage() but that
3324	* would be ugly in the extreme. So instead we would need to
3325	* replicate parts of the code in the above functions,
3326	* simplifying them because we wouldn't actually intend to
3327	* write out the pages, but rather only collect contiguous
3328	* logical block extents, call the multi-block allocator, and
3329	* then update the buffer heads with the block allocations.
3330	*
3331	* For now, though, we'll cheat by calling filemap_flush(),
3332	* which will map the blocks, and start the I/O, but not
3333	* actually wait for the I/O to complete.
3334	*/
3335	return filemap_flush(inode->i_mapping);
3336	}
3337
3338	/*
3339	* bmap() is special. It gets used by applications such as lilo and by
3340	* the swapper to find the on-disk block of a specific piece of data.
3341	*
3342	* Naturally, this is dangerous if the block concerned is still in the
3343	* journal. If somebody makes a swapfile on an ext4 data-journaling
3344	* filesystem and enables swap, then they may get a nasty shock when the
3345	* data getting swapped to that swapfile suddenly gets overwritten by
3346	* the original zero's written out previously to the journal and
3347	* awaiting writeback in the kernel's buffer cache.
3348	*
3349	* So, if we see any bmap calls here on a modified, data-journaled file,
3350	* take extra steps to flush any blocks which might be in the cache.
3351	*/
3352	static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3353	{
3354	struct inode *inode = mapping->host;
3355	sector_t ret = `0`;
3356
3357	inode_lock_shared(inode);
3358	/*
3359	* We can get here for an inline file via the FIBMAP ioctl
3360	*/
3361	if (ext4_has_inline_data(inode))
3362	goto out;
3363
3364	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3365	(test_opt(inode->i_sb, DELALLOC) \|\|
3366	ext4_should_journal_data(inode))) {
3367	/*
3368	* With delalloc or journalled data we want to sync the file so
3369	* that we can make sure we allocate blocks for file and data
3370	* is in place for the user to see it
3371	*/
3372	filemap_write_and_wait(mapping);
3373	}
3374
3375	ret = iomap_bmap(mapping, bno: block, ops: &ext4_iomap_ops);
3376
3377	out:
3378	inode_unlock_shared(inode);
3379	return ret;
3380	}
3381
3382	static int ext4_read_folio(struct file file, struct* folio *folio)
3383	{
3384	int ret = -EAGAIN;
3385	struct inode *inode = folio->mapping->host;
3386
3387	trace_ext4_read_folio(inode, folio);
3388
3389	if (ext4_has_inline_data(inode))
3390	ret = ext4_readpage_inline(inode, folio);
3391
3392	if (ret == -EAGAIN)
3393	return ext4_mpage_readpages(inode, NULL, folio);
3394
3395	return ret;
3396	}
3397
3398	static void ext4_readahead(struct readahead_control *rac)
3399	{
3400	struct inode *inode = rac->mapping->host;
3401
3402	/ If the file has inline data, no need to do readahead. /
3403	if (ext4_has_inline_data(inode))
3404	return;
3405
3406	ext4_mpage_readpages(inode, rac, NULL);
3407	}
3408
3409	static void ext4_invalidate_folio(struct folio *folio, size_t offset,
3410	size_t length)
3411	{
3412	trace_ext4_invalidate_folio(folio, offset, length);
3413
3414	/ No journalling happens on data buffers when this function is used /
3415	WARN_ON(folio_buffers(folio) && buffer_jbd(folio_buffers(folio)));
3416
3417	block_invalidate_folio(folio, offset, length);
3418	}
3419
3420	static int __ext4_journalled_invalidate_folio(struct folio *folio,
3421	size_t offset, size_t length)
3422	{
3423	journal_t *journal = EXT4_JOURNAL(folio->mapping->host);
3424
3425	trace_ext4_journalled_invalidate_folio(folio, offset, length);
3426
3427	/*
3428	* If it's a full truncate we just forget about the pending dirtying
3429	*/
3430	if (offset == `0` && length == folio_size(folio))
3431	folio_clear_checked(folio);
3432
3433	return jbd2_journal_invalidate_folio(journal, folio, offset, length);
3434	}
3435
3436	/ Wrapper for aops... /
3437	static void ext4_journalled_invalidate_folio(struct folio *folio,
3438	size_t offset,
3439	size_t length)
3440	{
3441	WARN_ON(__ext4_journalled_invalidate_folio(folio, offset, length) < `0`);
3442	}
3443
3444	static bool ext4_release_folio(struct folio *folio, gfp_t wait)
3445	{
3446	struct inode *inode = folio->mapping->host;
3447	journal_t *journal = EXT4_JOURNAL(inode);
3448
3449	trace_ext4_release_folio(inode, folio);
3450
3451	/ Page has dirty journalled data -> cannot release /
3452	if (folio_test_checked(folio))
3453	return false;
3454	if (journal)
3455	return jbd2_journal_try_to_free_buffers(journal, folio);
3456	else
3457	return try_to_free_buffers(folio);
3458	}
3459
3460	static bool ext4_inode_datasync_dirty(struct inode *inode)
3461	{
3462	journal_t *journal = EXT4_SB(sb: inode->i_sb)->s_journal;
3463
3464	if (journal) {
3465	if (jbd2_transaction_committed(journal,
3466	EXT4_I(inode)->i_datasync_tid))
3467	return false;
3468	if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3469	return !list_empty(head: &EXT4_I(inode)->i_fc_list);
3470	return true;
3471	}
3472
3473	/ Any metadata buffers to write? /
3474	if (!list_empty(head: &inode->i_mapping->i_private_list))
3475	return true;
3476	return inode->i_state & I_DIRTY_DATASYNC;
3477	}
3478
3479	static void ext4_set_iomap(struct inode inode, struct* iomap *iomap,
3480	struct ext4_map_blocks *map, loff_t offset,
3481	loff_t length, unsigned int flags)
3482	{
3483	u8 blkbits = inode->i_blkbits;
3484
3485	/*
3486	* Writes that span EOF might trigger an I/O size update on completion,
3487	* so consider them to be dirty for the purpose of O_DSYNC, even if
3488	* there is no other metadata changes being made or are pending.
3489	*/
3490	iomap->flags = `0`;
3491	if (ext4_inode_datasync_dirty(inode) \|\|
3492	offset + length > i_size_read(inode))
3493	iomap->flags \|= IOMAP_F_DIRTY;
3494
3495	if (map->m_flags & EXT4_MAP_NEW)
3496	iomap->flags \|= IOMAP_F_NEW;
3497
3498	/ HW-offload atomics are always used /
3499	if (flags & IOMAP_ATOMIC)
3500	iomap->flags \|= IOMAP_F_ATOMIC_BIO;
3501
3502	if (flags & IOMAP_DAX)
3503	iomap->dax_dev = EXT4_SB(sb: inode->i_sb)->s_daxdev;
3504	else
3505	iomap->bdev = inode->i_sb->s_bdev;
3506	iomap->offset = (u64) map->m_lblk << blkbits;
3507	iomap->length = (u64) map->m_len << blkbits;
3508
3509	if ((map->m_flags & EXT4_MAP_MAPPED) &&
3510	!ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
3511	iomap->flags \|= IOMAP_F_MERGED;
3512
3513	/*
3514	* Flags passed to ext4_map_blocks() for direct I/O writes can result
3515	* in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3516	* set. In order for any allocated unwritten extents to be converted
3517	* into written extents correctly within the ->end_io() handler, we
3518	* need to ensure that the iomap->type is set appropriately. Hence, the
3519	* reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3520	* been set first.
3521	*/
3522	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3523	iomap->type = IOMAP_UNWRITTEN;
3524	iomap->addr = (u64) map->m_pblk << blkbits;
3525	if (flags & IOMAP_DAX)
3526	iomap->addr += EXT4_SB(sb: inode->i_sb)->s_dax_part_off;
3527	} else if (map->m_flags & EXT4_MAP_MAPPED) {
3528	iomap->type = IOMAP_MAPPED;
3529	iomap->addr = (u64) map->m_pblk << blkbits;
3530	if (flags & IOMAP_DAX)
3531	iomap->addr += EXT4_SB(sb: inode->i_sb)->s_dax_part_off;
3532	} else if (map->m_flags & EXT4_MAP_DELAYED) {
3533	iomap->type = IOMAP_DELALLOC;
3534	iomap->addr = IOMAP_NULL_ADDR;
3535	} else {
3536	iomap->type = IOMAP_HOLE;
3537	iomap->addr = IOMAP_NULL_ADDR;
3538	}
3539	}
3540
3541	static int ext4_map_blocks_atomic_write_slow(handle_t *handle,
3542	struct inode inode, struct* ext4_map_blocks *map)
3543	{
3544	ext4_lblk_t m_lblk = map->m_lblk;
3545	unsigned int m_len = map->m_len;
3546	unsigned int mapped_len = `0`, m_flags = `0`;
3547	ext4_fsblk_t next_pblk;
3548	bool check_next_pblk = false;
3549	int ret = `0`;
3550
3551	WARN_ON_ONCE(!ext4_has_feature_bigalloc(inode->i_sb));
3552
3553	/*
3554	* This is a slow path in case of mixed mapping. We use
3555	* EXT4_GET_BLOCKS_CREATE_ZERO flag here to make sure we get a single
3556	* contiguous mapped mapping. This will ensure any unwritten or hole
3557	* regions within the requested range is zeroed out and we return
3558	* a single contiguous mapped extent.
3559	*/
3560	m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3561
3562	do {
3563	ret = ext4_map_blocks(handle, inode, map, flags: m_flags);
3564	if (ret < `0` && ret != -ENOSPC)
3565	goto out_err;
3566	/*
3567	* This should never happen, but let's return an error code to
3568	* avoid an infinite loop in here.
3569	*/
3570	if (ret == `0`) {
3571	ret = -EFSCORRUPTED;
3572	ext4_warning_inode(inode,
3573	"ext4_map_blocks() couldn't allocate blocks m_flags: 0x%x, ret:%d",
3574	m_flags, ret);
3575	goto out_err;
3576	}
3577	/*
3578	* With bigalloc we should never get ENOSPC nor discontiguous
3579	* physical extents.
3580	*/
3581	if ((check_next_pblk && next_pblk != map->m_pblk) \|\|
3582	ret == -ENOSPC) {
3583	ext4_warning_inode(inode,
3584	"Non-contiguous allocation detected: expected %llu, got %llu, "
3585	"or ext4_map_blocks() returned out of space ret: %d",
3586	next_pblk, map->m_pblk, ret);
3587	ret = -EFSCORRUPTED;
3588	goto out_err;
3589	}
3590	next_pblk = map->m_pblk + map->m_len;
3591	check_next_pblk = true;
3592
3593	mapped_len += map->m_len;
3594	map->m_lblk += map->m_len;
3595	map->m_len = m_len - mapped_len;
3596	} while (mapped_len < m_len);
3597
3598	/*
3599	* We might have done some work in above loop, so we need to query the
3600	* start of the physical extent, based on the origin m_lblk and m_len.
3601	* Let's also ensure we were able to allocate the required range for
3602	* mixed mapping case.
3603	*/
3604	map->m_lblk = m_lblk;
3605	map->m_len = m_len;
3606	map->m_flags = `0`;
3607
3608	ret = ext4_map_blocks(handle, inode, map,
3609	EXT4_GET_BLOCKS_QUERY_LAST_IN_LEAF);
3610	if (ret != m_len) {
3611	ext4_warning_inode(inode,
3612	"allocation failed for atomic write request m_lblk:%u, m_len:%u, ret:%d\n",
3613	m_lblk, m_len, ret);
3614	ret = -EINVAL;
3615	}
3616	return ret;
3617
3618	out_err:
3619	/ reset map before returning an error /
3620	map->m_lblk = m_lblk;
3621	map->m_len = m_len;
3622	map->m_flags = `0`;
3623	return ret;
3624	}
3625
3626	/*
3627	* ext4_map_blocks_atomic: Helper routine to ensure the entire requested
3628	* range in @map [lblk, lblk + len) is one single contiguous extent with no
3629	* mixed mappings.
3630	*
3631	* We first use m_flags passed to us by our caller (ext4_iomap_alloc()).
3632	* We only call EXT4_GET_BLOCKS_ZERO in the slow path, when the underlying
3633	* physical extent for the requested range does not have a single contiguous
3634	* mapping type i.e. (Hole, Mapped, or Unwritten) throughout.
3635	* In that case we will loop over the requested range to allocate and zero out
3636	* the unwritten / holes in between, to get a single mapped extent from
3637	* [m_lblk, m_lblk + m_len). Note that this is only possible because we know
3638	* this can be called only with bigalloc enabled filesystem where the underlying
3639	* cluster is already allocated. This avoids allocating discontiguous extents
3640	* in the slow path due to multiple calls to ext4_map_blocks().
3641	* The slow path is mostly non-performance critical path, so it should be ok to
3642	* loop using ext4_map_blocks() with appropriate flags to allocate & zero the
3643	* underlying short holes/unwritten extents within the requested range.
3644	*/
3645	static int ext4_map_blocks_atomic_write(handle_t handle, struct* inode *inode,
3646	struct ext4_map_blocks map, int* m_flags,
3647	bool *force_commit)
3648	{
3649	ext4_lblk_t m_lblk = map->m_lblk;
3650	unsigned int m_len = map->m_len;
3651	int ret = `0`;
3652
3653	WARN_ON_ONCE(m_len > `1` && !ext4_has_feature_bigalloc(inode->i_sb));
3654
3655	ret = ext4_map_blocks(handle, inode, map, flags: m_flags);
3656	if (ret < `0` \|\| ret == m_len)
3657	goto out;
3658	/*
3659	* This is a mixed mapping case where we were not able to allocate
3660	* a single contiguous extent. In that case let's reset requested
3661	* mapping and call the slow path.
3662	*/
3663	map->m_lblk = m_lblk;
3664	map->m_len = m_len;
3665	map->m_flags = `0`;
3666
3667	/*
3668	* slow path means we have mixed mapping, that means we will need
3669	* to force txn commit.
3670	*/
3671	*force_commit = true;
3672	return ext4_map_blocks_atomic_write_slow(handle, inode, map);
3673	out:
3674	return ret;
3675	}
3676
3677	static int ext4_iomap_alloc(struct inode inode, struct* ext4_map_blocks *map,
3678	unsigned int flags)
3679	{
3680	handle_t *handle;
3681	u8 blkbits = inode->i_blkbits;
3682	int ret, dio_credits, m_flags = `0`, retries = `0`;
3683	bool force_commit = false;
3684
3685	/*
3686	* Trim the mapping request to the maximum value that we can map at
3687	* once for direct I/O.
3688	*/
3689	if (map->m_len > DIO_MAX_BLOCKS)
3690	map->m_len = DIO_MAX_BLOCKS;
3691
3692	/*
3693	* journal credits estimation for atomic writes. We call
3694	* ext4_map_blocks(), to find if there could be a mixed mapping. If yes,
3695	* then let's assume the no. of pextents required can be m_len i.e.
3696	* every alternate block can be unwritten and hole.
3697	*/
3698	if (flags & IOMAP_ATOMIC) {
3699	unsigned int orig_mlen = map->m_len;
3700
3701	ret = ext4_map_blocks(NULL, inode, map, flags: `0`);
3702	if (ret < `0`)
3703	return ret;
3704	if (map->m_len < orig_mlen) {
3705	map->m_len = orig_mlen;
3706	dio_credits = ext4_meta_trans_blocks(inode, lblocks: orig_mlen,
3707	pextents: map->m_len);
3708	} else {
3709	dio_credits = ext4_chunk_trans_blocks(inode,
3710	nrblocks: map->m_len);
3711	}
3712	} else {
3713	dio_credits = ext4_chunk_trans_blocks(inode, nrblocks: map->m_len);
3714	}
3715
3716	retry:
3717	/*
3718	* Either we allocate blocks and then don't get an unwritten extent, so
3719	* in that case we have reserved enough credits. Or, the blocks are
3720	* already allocated and unwritten. In that case, the extent conversion
3721	* fits into the credits as well.
3722	*/
3723	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3724	if (IS_ERR(ptr: handle))
3725	return PTR_ERR(ptr: handle);
3726
3727	/*
3728	* DAX and direct I/O are the only two operations that are currently
3729	* supported with IOMAP_WRITE.
3730	*/
3731	WARN_ON(!(flags & (IOMAP_DAX \| IOMAP_DIRECT)));
3732	if (flags & IOMAP_DAX)
3733	m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3734	/*
3735	* We use i_size instead of i_disksize here because delalloc writeback
3736	* can complete at any point during the I/O and subsequently push the
3737	* i_disksize out to i_size. This could be beyond where direct I/O is
3738	* happening and thus expose allocated blocks to direct I/O reads.
3739	*/
3740	else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
3741	m_flags = EXT4_GET_BLOCKS_CREATE;
3742	else if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
3743	m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3744
3745	if (flags & IOMAP_ATOMIC)
3746	ret = ext4_map_blocks_atomic_write(handle, inode, map, m_flags,
3747	force_commit: &force_commit);
3748	else
3749	ret = ext4_map_blocks(handle, inode, map, flags: m_flags);
3750
3751	/*
3752	* We cannot fill holes in indirect tree based inodes as that could
3753	* expose stale data in the case of a crash. Use the magic error code
3754	* to fallback to buffered I/O.
3755	*/
3756	if (!m_flags && !ret)
3757	ret = -ENOTBLK;
3758
3759	ext4_journal_stop(handle);
3760	if (ret == -ENOSPC && ext4_should_retry_alloc(sb: inode->i_sb, retries: &retries))
3761	goto retry;
3762
3763	/*
3764	* Force commit the current transaction if the allocation spans a mixed
3765	* mapping range. This ensures any pending metadata updates (like
3766	* unwritten to written extents conversion) in this range are in
3767	* consistent state with the file data blocks, before performing the
3768	* actual write I/O. If the commit fails, the whole I/O must be aborted
3769	* to prevent any possible torn writes.
3770	*/
3771	if (ret > `0` && force_commit) {
3772	int ret2;
3773
3774	ret2 = ext4_force_commit(sb: inode->i_sb);
3775	if (ret2)
3776	return ret2;
3777	}
3778
3779	return ret;
3780	}
3781
3782
3783	static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3784	unsigned flags, struct iomap iomap, struct* iomap *srcmap)
3785	{
3786	int ret;
3787	struct ext4_map_blocks map;
3788	u8 blkbits = inode->i_blkbits;
3789	unsigned int orig_mlen;
3790
3791	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3792	return -EINVAL;
3793
3794	if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3795	return -ERANGE;
3796
3797	/*
3798	* Calculate the first and last logical blocks respectively.
3799	*/
3800	map.m_lblk = offset >> blkbits;
3801	map.m_len = min_t(loff_t, (offset + length - `1`) >> blkbits,
3802	EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + `1`;
3803	orig_mlen = map.m_len;
3804
3805	if (flags & IOMAP_WRITE) {
3806	/*
3807	* We check here if the blocks are already allocated, then we
3808	* don't need to start a journal txn and we can directly return
3809	* the mapping information. This could boost performance
3810	* especially in multi-threaded overwrite requests.
3811	*/
3812	if (offset + length <= i_size_read(inode)) {
3813	ret = ext4_map_blocks(NULL, inode, map: &map, flags: `0`);
3814	/*
3815	* For atomic writes the entire requested length should
3816	* be mapped.
3817	*/
3818	if (map.m_flags & EXT4_MAP_MAPPED) {
3819	if ((!(flags & IOMAP_ATOMIC) && ret > `0`) \|\|
3820	(flags & IOMAP_ATOMIC && ret >= orig_mlen))
3821	goto out;
3822	}
3823	map.m_len = orig_mlen;
3824	}
3825	ret = ext4_iomap_alloc(inode, map: &map, flags);
3826	} else {
3827	/*
3828	* This can be called for overwrites path from
3829	* ext4_iomap_overwrite_begin().
3830	*/
3831	ret = ext4_map_blocks(NULL, inode, map: &map, flags: `0`);
3832	}
3833
3834	if (ret < `0`)
3835	return ret;
3836	out:
3837	/*
3838	* When inline encryption is enabled, sometimes I/O to an encrypted file
3839	* has to be broken up to guarantee DUN contiguity. Handle this by
3840	* limiting the length of the mapping returned.
3841	*/
3842	map.m_len = fscrypt_limit_io_blocks(inode, lblk: map.m_lblk, nr_blocks: map.m_len);
3843
3844	/*
3845	* Before returning to iomap, let's ensure the allocated mapping
3846	* covers the entire requested length for atomic writes.
3847	*/
3848	if (flags & IOMAP_ATOMIC) {
3849	if (map.m_len < (length >> blkbits)) {
3850	WARN_ON_ONCE(`1`);
3851	return -EINVAL;
3852	}
3853	}
3854	ext4_set_iomap(inode, iomap, map: &map, offset, length, flags);
3855
3856	return `0`;
3857	}
3858
3859	static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3860	loff_t length, unsigned flags, struct iomap *iomap,
3861	struct iomap *srcmap)
3862	{
3863	int ret;
3864
3865	/*
3866	* Even for writes we don't need to allocate blocks, so just pretend
3867	* we are reading to save overhead of starting a transaction.
3868	*/
3869	flags &= ~IOMAP_WRITE;
3870	ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3871	WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED);
3872	return ret;
3873	}
3874
3875	const struct iomap_ops ext4_iomap_ops = {
3876	.iomap_begin = ext4_iomap_begin,
3877	};
3878
3879	const struct iomap_ops ext4_iomap_overwrite_ops = {
3880	.iomap_begin = ext4_iomap_overwrite_begin,
3881	};
3882
3883	static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3884	loff_t length, unsigned int flags,
3885	struct iomap iomap, struct* iomap *srcmap)
3886	{
3887	int ret;
3888	struct ext4_map_blocks map;
3889	u8 blkbits = inode->i_blkbits;
3890
3891	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3892	return -EINVAL;
3893
3894	if (ext4_has_inline_data(inode)) {
3895	ret = ext4_inline_data_iomap(inode, iomap);
3896	if (ret != -EAGAIN) {
3897	if (ret == `0` && offset >= iomap->length)
3898	ret = -ENOENT;
3899	return ret;
3900	}
3901	}
3902
3903	/*
3904	* Calculate the first and last logical block respectively.
3905	*/
3906	map.m_lblk = offset >> blkbits;
3907	map.m_len = min_t(loff_t, (offset + length - `1`) >> blkbits,
3908	EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + `1`;
3909
3910	/*
3911	* Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3912	* So handle it here itself instead of querying ext4_map_blocks().
3913	* Since ext4_map_blocks() will warn about it and will return
3914	* -EIO error.
3915	*/
3916	if (!(ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))) {
3917	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
3918
3919	if (offset >= sbi->s_bitmap_maxbytes) {
3920	map.m_flags = `0`;
3921	goto set_iomap;
3922	}
3923	}
3924
3925	ret = ext4_map_blocks(NULL, inode, map: &map, flags: `0`);
3926	if (ret < `0`)
3927	return ret;
3928	set_iomap:
3929	ext4_set_iomap(inode, iomap, map: &map, offset, length, flags);
3930
3931	return `0`;
3932	}
3933
3934	const struct iomap_ops ext4_iomap_report_ops = {
3935	.iomap_begin = ext4_iomap_begin_report,
3936	};
3937
3938	/*
3939	* For data=journal mode, folio should be marked dirty only when it was
3940	* writeably mapped. When that happens, it was already attached to the
3941	* transaction and marked as jbddirty (we take care of this in
3942	* ext4_page_mkwrite()). On transaction commit, we writeprotect page mappings
3943	* so we should have nothing to do here, except for the case when someone
3944	* had the page pinned and dirtied the page through this pin (e.g. by doing
3945	* direct IO to it). In that case we'd need to attach buffers here to the
3946	* transaction but we cannot due to lock ordering. We cannot just dirty the
3947	* folio and leave attached buffers clean, because the buffers' dirty state is
3948	* "definitive". We cannot just set the buffers dirty or jbddirty because all
3949	* the journalling code will explode. So what we do is to mark the folio
3950	* "pending dirty" and next time ext4_writepages() is called, attach buffers
3951	* to the transaction appropriately.
3952	*/
3953	static bool ext4_journalled_dirty_folio(struct address_space *mapping,
3954	struct folio *folio)
3955	{
3956	WARN_ON_ONCE(!folio_buffers(folio));
3957	if (folio_maybe_dma_pinned(folio))
3958	folio_set_checked(folio);
3959	return filemap_dirty_folio(mapping, folio);
3960	}
3961
3962	static bool ext4_dirty_folio(struct address_space mapping, struct* folio *folio)
3963	{
3964	WARN_ON_ONCE(!folio_test_locked(folio) && !folio_test_dirty(folio));
3965	WARN_ON_ONCE(!folio_buffers(folio));
3966	return block_dirty_folio(mapping, folio);
3967	}
3968
3969	static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3970	struct file file, sector_t span)
3971	{
3972	return iomap_swapfile_activate(sis, swap_file: file, pagespan: span,
3973	ops: &ext4_iomap_report_ops);
3974	}
3975
3976	static const struct address_space_operations ext4_aops = {
3977	.read_folio = ext4_read_folio,
3978	.readahead = ext4_readahead,
3979	.writepages = ext4_writepages,
3980	.write_begin = ext4_write_begin,
3981	.write_end = ext4_write_end,
3982	.dirty_folio = ext4_dirty_folio,
3983	.bmap = ext4_bmap,
3984	.invalidate_folio = ext4_invalidate_folio,
3985	.release_folio = ext4_release_folio,
3986	.migrate_folio = buffer_migrate_folio,
3987	.is_partially_uptodate = block_is_partially_uptodate,
3988	.error_remove_folio = generic_error_remove_folio,
3989	.swap_activate = ext4_iomap_swap_activate,
3990	};
3991
3992	static const struct address_space_operations ext4_journalled_aops = {
3993	.read_folio = ext4_read_folio,
3994	.readahead = ext4_readahead,
3995	.writepages = ext4_writepages,
3996	.write_begin = ext4_write_begin,
3997	.write_end = ext4_journalled_write_end,
3998	.dirty_folio = ext4_journalled_dirty_folio,
3999	.bmap = ext4_bmap,
4000	.invalidate_folio = ext4_journalled_invalidate_folio,
4001	.release_folio = ext4_release_folio,
4002	.migrate_folio = buffer_migrate_folio_norefs,
4003	.is_partially_uptodate = block_is_partially_uptodate,
4004	.error_remove_folio = generic_error_remove_folio,
4005	.swap_activate = ext4_iomap_swap_activate,
4006	};
4007
4008	static const struct address_space_operations ext4_da_aops = {
4009	.read_folio = ext4_read_folio,
4010	.readahead = ext4_readahead,
4011	.writepages = ext4_writepages,
4012	.write_begin = ext4_da_write_begin,
4013	.write_end = ext4_da_write_end,
4014	.dirty_folio = ext4_dirty_folio,
4015	.bmap = ext4_bmap,
4016	.invalidate_folio = ext4_invalidate_folio,
4017	.release_folio = ext4_release_folio,
4018	.migrate_folio = buffer_migrate_folio,
4019	.is_partially_uptodate = block_is_partially_uptodate,
4020	.error_remove_folio = generic_error_remove_folio,
4021	.swap_activate = ext4_iomap_swap_activate,
4022	};
4023
4024	static const struct address_space_operations ext4_dax_aops = {
4025	.writepages = ext4_dax_writepages,
4026	.dirty_folio = noop_dirty_folio,
4027	.bmap = ext4_bmap,
4028	.swap_activate = ext4_iomap_swap_activate,
4029	};
4030
4031	void ext4_set_aops(struct inode *inode)
4032	{
4033	switch (ext4_inode_journal_mode(inode)) {
4034	case EXT4_INODE_ORDERED_DATA_MODE:
4035	case EXT4_INODE_WRITEBACK_DATA_MODE:
4036	break;
4037	case EXT4_INODE_JOURNAL_DATA_MODE:
4038	inode->i_mapping->a_ops = &ext4_journalled_aops;
4039	return;
4040	default:
4041	BUG();
4042	}
4043	if (IS_DAX(inode))
4044	inode->i_mapping->a_ops = &ext4_dax_aops;
4045	else if (test_opt(inode->i_sb, DELALLOC))
4046	inode->i_mapping->a_ops = &ext4_da_aops;
4047	else
4048	inode->i_mapping->a_ops = &ext4_aops;
4049	}
4050
4051	/*
4052	* Here we can't skip an unwritten buffer even though it usually reads zero
4053	* because it might have data in pagecache (eg, if called from ext4_zero_range,
4054	* ext4_punch_hole, etc) which needs to be properly zeroed out. Otherwise a
4055	* racing writeback can come later and flush the stale pagecache to disk.
4056	*/
4057	static int __ext4_block_zero_page_range(handle_t *handle,
4058	struct address_space *mapping, loff_t from, loff_t length)
4059	{
4060	unsigned int offset, blocksize, pos;
4061	ext4_lblk_t iblock;
4062	struct inode *inode = mapping->host;
4063	struct buffer_head *bh;
4064	struct folio *folio;
4065	int err = `0`;
4066
4067	folio = __filemap_get_folio(mapping, index: from >> PAGE_SHIFT,
4068	FGP_LOCK \| FGP_ACCESSED \| FGP_CREAT,
4069	gfp: mapping_gfp_constraint(mapping, gfp_mask: ~__GFP_FS));
4070	if (IS_ERR(ptr: folio))
4071	return PTR_ERR(ptr: folio);
4072
4073	blocksize = inode->i_sb->s_blocksize;
4074
4075	iblock = folio->index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
4076
4077	bh = folio_buffers(folio);
4078	if (!bh)
4079	bh = create_empty_buffers(folio, blocksize, b_state: `0`);
4080
4081	/ Find the buffer that contains "offset" /
4082	offset = offset_in_folio(folio, from);
4083	pos = blocksize;
4084	while (offset >= pos) {
4085	bh = bh->b_this_page;
4086	iblock++;
4087	pos += blocksize;
4088	}
4089	if (buffer_freed(bh)) {
4090	BUFFER_TRACE(bh, "freed: skip");
4091	goto unlock;
4092	}
4093	if (!buffer_mapped(bh)) {
4094	BUFFER_TRACE(bh, "unmapped");
4095	ext4_get_block(inode, iblock, bh, create: `0`);
4096	/ unmapped? It's a hole - nothing to do /
4097	if (!buffer_mapped(bh)) {
4098	BUFFER_TRACE(bh, "still unmapped");
4099	goto unlock;
4100	}
4101	}
4102
4103	/ Ok, it's mapped. Make sure it's up-to-date /
4104	if (folio_test_uptodate(folio))
4105	set_buffer_uptodate(bh);
4106
4107	if (!buffer_uptodate(bh)) {
4108	err = ext4_read_bh_lock(bh, op_flags: `0`, wait: true);
4109	if (err)
4110	goto unlock;
4111	if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
4112	/ We expect the key to be set. /
4113	BUG_ON(!fscrypt_has_encryption_key(inode));
4114	err = fscrypt_decrypt_pagecache_blocks(folio,
4115	len: blocksize,
4116	offs: bh_offset(bh));
4117	if (err) {
4118	clear_buffer_uptodate(bh);
4119	goto unlock;
4120	}
4121	}
4122	}
4123	if (ext4_should_journal_data(inode)) {
4124	BUFFER_TRACE(bh, "get write access");
4125	err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
4126	EXT4_JTR_NONE);
4127	if (err)
4128	goto unlock;
4129	}
4130	folio_zero_range(folio, start: offset, length);
4131	BUFFER_TRACE(bh, "zeroed end of block");
4132
4133	if (ext4_should_journal_data(inode)) {
4134	err = ext4_dirty_journalled_data(handle, bh);
4135	} else {
4136	err = `0`;
4137	mark_buffer_dirty(bh);
4138	if (ext4_should_order_data(inode))
4139	err = ext4_jbd2_inode_add_write(handle, inode, start_byte: from,
4140	length);
4141	}
4142
4143	unlock:
4144	folio_unlock(folio);
4145	folio_put(folio);
4146	return err;
4147	}
4148
4149	/*
4150	* ext4_block_zero_page_range() zeros out a mapping of length 'length'
4151	* starting from file offset 'from'. The range to be zero'd must
4152	* be contained with in one block. If the specified range exceeds
4153	* the end of the block it will be shortened to end of the block
4154	* that corresponds to 'from'
4155	*/
4156	static int ext4_block_zero_page_range(handle_t *handle,
4157	struct address_space *mapping, loff_t from, loff_t length)
4158	{
4159	struct inode *inode = mapping->host;
4160	unsigned offset = from & (PAGE_SIZE-`1`);
4161	unsigned blocksize = inode->i_sb->s_blocksize;
4162	unsigned max = blocksize - (offset & (blocksize - `1`));
4163
4164	/*
4165	* correct length if it does not fall between
4166	* 'from' and the end of the block
4167	*/
4168	if (length > max \|\| length < `0`)
4169	length = max;
4170
4171	if (IS_DAX(inode)) {
4172	return dax_zero_range(inode, pos: from, len: length, NULL,
4173	ops: &ext4_iomap_ops);
4174	}
4175	return __ext4_block_zero_page_range(handle, mapping, from, length);
4176	}
4177
4178	/*
4179	* ext4_block_truncate_page() zeroes out a mapping from file offset `from'
4180	* up to the end of the block which corresponds to `from'.
4181	* This required during truncate. We need to physically zero the tail end
4182	* of that block so it doesn't yield old data if the file is later grown.
4183	*/
4184	static int ext4_block_truncate_page(handle_t *handle,
4185	struct address_space *mapping, loff_t from)
4186	{
4187	unsigned offset = from & (PAGE_SIZE-`1`);
4188	unsigned length;
4189	unsigned blocksize;
4190	struct inode *inode = mapping->host;
4191
4192	/ If we are processing an encrypted inode during orphan list handling /
4193	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
4194	return `0`;
4195
4196	blocksize = inode->i_sb->s_blocksize;
4197	length = blocksize - (offset & (blocksize - `1`));
4198
4199	return ext4_block_zero_page_range(handle, mapping, from, length);
4200	}
4201
4202	int ext4_zero_partial_blocks(handle_t handle, struct* inode *inode,
4203	loff_t lstart, loff_t length)
4204	{
4205	struct super_block *sb = inode->i_sb;
4206	struct address_space *mapping = inode->i_mapping;
4207	unsigned partial_start, partial_end;
4208	ext4_fsblk_t start, end;
4209	loff_t byte_end = (lstart + length - `1`);
4210	int err = `0`;
4211
4212	partial_start = lstart & (sb->s_blocksize - `1`);
4213	partial_end = byte_end & (sb->s_blocksize - `1`);
4214
4215	start = lstart >> sb->s_blocksize_bits;
4216	end = byte_end >> sb->s_blocksize_bits;
4217
4218	/ Handle partial zero within the single block /
4219	if (start == end &&
4220	(partial_start \|\| (partial_end != sb->s_blocksize - `1`))) {
4221	err = ext4_block_zero_page_range(handle, mapping,
4222	from: lstart, length);
4223	return err;
4224	}
4225	/ Handle partial zero out on the start of the range /
4226	if (partial_start) {
4227	err = ext4_block_zero_page_range(handle, mapping,
4228	from: lstart, length: sb->s_blocksize);
4229	if (err)
4230	return err;
4231	}
4232	/ Handle partial zero out on the end of the range /
4233	if (partial_end != sb->s_blocksize - `1`)
4234	err = ext4_block_zero_page_range(handle, mapping,
4235	from: byte_end - partial_end,
4236	length: partial_end + `1`);
4237	return err;
4238	}
4239
4240	int ext4_can_truncate(struct inode *inode)
4241	{
4242	if (S_ISREG(inode->i_mode))
4243	return `1`;
4244	if (S_ISDIR(inode->i_mode))
4245	return `1`;
4246	if (S_ISLNK(inode->i_mode))
4247	return !ext4_inode_is_fast_symlink(inode);
4248	return `0`;
4249	}
4250
4251	/*
4252	* We have to make sure i_disksize gets properly updated before we truncate
4253	* page cache due to hole punching or zero range. Otherwise i_disksize update
4254	* can get lost as it may have been postponed to submission of writeback but
4255	* that will never happen if we remove the folio containing i_size from the
4256	* page cache. Also if we punch hole within i_size but above i_disksize,
4257	* following ext4_page_mkwrite() may mistakenly allocate written blocks over
4258	* the hole and thus introduce allocated blocks beyond i_disksize which is
4259	* not allowed (e2fsck would complain in case of crash).
4260	*/
4261	int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
4262	loff_t len)
4263	{
4264	handle_t *handle;
4265	int ret;
4266
4267	loff_t size = i_size_read(inode);
4268
4269	WARN_ON(!inode_is_locked(inode));
4270	if (offset > size)
4271	return `0`;
4272
4273	if (offset + len < size)
4274	size = offset + len;
4275	if (EXT4_I(inode)->i_disksize >= size)
4276	return `0`;
4277
4278	handle = ext4_journal_start(inode, EXT4_HT_MISC, `1`);
4279	if (IS_ERR(ptr: handle))
4280	return PTR_ERR(ptr: handle);
4281	ext4_update_i_disksize(inode, newsize: size);
4282	ret = ext4_mark_inode_dirty(handle, inode);
4283	ext4_journal_stop(handle);
4284
4285	return ret;
4286	}
4287
4288	static inline void ext4_truncate_folio(struct inode *inode,
4289	loff_t start, loff_t end)
4290	{
4291	unsigned long blocksize = i_blocksize(node: inode);
4292	struct folio *folio;
4293
4294	/ Nothing to be done if no complete block needs to be truncated. /
4295	if (round_up(start, blocksize) >= round_down(end, blocksize))
4296	return;
4297
4298	folio = filemap_lock_folio(mapping: inode->i_mapping, index: start >> PAGE_SHIFT);
4299	if (IS_ERR(ptr: folio))
4300	return;
4301
4302	if (folio_mkclean(folio))
4303	folio_mark_dirty(folio);
4304	folio_unlock(folio);
4305	folio_put(folio);
4306	}
4307
4308	int ext4_truncate_page_cache_block_range(struct inode *inode,
4309	loff_t start, loff_t end)
4310	{
4311	unsigned long blocksize = i_blocksize(node: inode);
4312	int ret;
4313
4314	/*
4315	* For journalled data we need to write (and checkpoint) pages
4316	* before discarding page cache to avoid inconsitent data on disk
4317	* in case of crash before freeing or unwritten converting trans
4318	* is committed.
4319	*/
4320	if (ext4_should_journal_data(inode)) {
4321	ret = filemap_write_and_wait_range(mapping: inode->i_mapping, lstart: start,
4322	lend: end - `1`);
4323	if (ret)
4324	return ret;
4325	goto truncate_pagecache;
4326	}
4327
4328	/*
4329	* If the block size is less than the page size, the file's mapped
4330	* blocks within one page could be freed or converted to unwritten.
4331	* So it's necessary to remove writable userspace mappings, and then
4332	* ext4_page_mkwrite() can be called during subsequent write access
4333	* to these partial folios.
4334	*/
4335	if (!IS_ALIGNED(start \| end, PAGE_SIZE) &&
4336	blocksize < PAGE_SIZE && start < inode->i_size) {
4337	loff_t page_boundary = round_up(start, PAGE_SIZE);
4338
4339	ext4_truncate_folio(inode, start, min(page_boundary, end));
4340	if (end > page_boundary)
4341	ext4_truncate_folio(inode,
4342	round_down(end, PAGE_SIZE), end);
4343	}
4344
4345	truncate_pagecache:
4346	truncate_pagecache_range(inode, offset: start, end: end - `1`);
4347	return `0`;
4348	}
4349
4350	static void ext4_wait_dax_page(struct inode *inode)
4351	{
4352	filemap_invalidate_unlock(mapping: inode->i_mapping);
4353	schedule();
4354	filemap_invalidate_lock(mapping: inode->i_mapping);
4355	}
4356
4357	int ext4_break_layouts(struct inode *inode)
4358	{
4359	if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock)))
4360	return -EINVAL;
4361
4362	return dax_break_layout_inode(inode, cb: ext4_wait_dax_page);
4363	}
4364
4365	/*
4366	* ext4_punch_hole: punches a hole in a file by releasing the blocks
4367	* associated with the given offset and length
4368	*
4369	* @inode: File inode
4370	* @offset: The offset where the hole will begin
4371	* @len: The length of the hole
4372	*
4373	* Returns: 0 on success or negative on failure
4374	*/
4375
4376	int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
4377	{
4378	struct inode *inode = file_inode(f: file);
4379	struct super_block *sb = inode->i_sb;
4380	ext4_lblk_t start_lblk, end_lblk;
4381	loff_t max_end = sb->s_maxbytes;
4382	loff_t end = offset + length;
4383	handle_t *handle;
4384	unsigned int credits;
4385	int ret;
4386
4387	trace_ext4_punch_hole(inode, offset, len: length, mode: `0`);
4388	WARN_ON_ONCE(!inode_is_locked(inode));
4389
4390	/*
4391	* For indirect-block based inodes, make sure that the hole within
4392	* one block before last range.
4393	*/
4394	if (!ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
4395	max_end = EXT4_SB(sb)->s_bitmap_maxbytes - sb->s_blocksize;
4396
4397	/ No need to punch hole beyond i_size /
4398	if (offset >= inode->i_size \|\| offset >= max_end)
4399	return `0`;
4400
4401	/*
4402	* If the hole extends beyond i_size, set the hole to end after
4403	* the page that contains i_size.
4404	*/
4405	if (end > inode->i_size)
4406	end = round_up(inode->i_size, PAGE_SIZE);
4407	if (end > max_end)
4408	end = max_end;
4409	length = end - offset;
4410
4411	/*
4412	* Attach jinode to inode for jbd2 if we do any zeroing of partial
4413	* block.
4414	*/
4415	if (!IS_ALIGNED(offset \| end, sb->s_blocksize)) {
4416	ret = ext4_inode_attach_jinode(inode);
4417	if (ret < `0`)
4418	return ret;
4419	}
4420
4421
4422	ret = ext4_update_disksize_before_punch(inode, offset, len: length);
4423	if (ret)
4424	return ret;
4425
4426	/ Now release the pages and zero block aligned part of pages/
4427	ret = ext4_truncate_page_cache_block_range(inode, start: offset, end);
4428	if (ret)
4429	return ret;
4430
4431	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
4432	credits = ext4_chunk_trans_extent(inode, nrblocks: `2`);
4433	else
4434	credits = ext4_blocks_for_truncate(inode);
4435	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4436	if (IS_ERR(ptr: handle)) {
4437	ret = PTR_ERR(ptr: handle);
4438	ext4_std_error(sb, ret);
4439	return ret;
4440	}
4441
4442	ret = ext4_zero_partial_blocks(handle, inode, lstart: offset, length);
4443	if (ret)
4444	goto out_handle;
4445
4446	/ If there are blocks to remove, do it /
4447	start_lblk = EXT4_B_TO_LBLK(inode, offset);
4448	end_lblk = end >> inode->i_blkbits;
4449
4450	if (end_lblk > start_lblk) {
4451	ext4_lblk_t hole_len = end_lblk - start_lblk;
4452
4453	ext4_fc_track_inode(handle, inode);
4454	ext4_check_map_extents_env(inode);
4455	down_write(sem: &EXT4_I(inode)->i_data_sem);
4456	ext4_discard_preallocations(inode);
4457
4458	ext4_es_remove_extent(inode, lblk: start_lblk, len: hole_len);
4459
4460	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
4461	ret = ext4_ext_remove_space(inode, start: start_lblk,
4462	end: end_lblk - `1`);
4463	else
4464	ret = ext4_ind_remove_space(handle, inode, start: start_lblk,
4465	end: end_lblk);
4466	if (ret) {
4467	up_write(sem: &EXT4_I(inode)->i_data_sem);
4468	goto out_handle;
4469	}
4470
4471	ext4_es_insert_extent(inode, lblk: start_lblk, len: hole_len, pblk: ~`0`,
4472	EXTENT_STATUS_HOLE, delalloc_reserve_used: `0`);
4473	up_write(sem: &EXT4_I(inode)->i_data_sem);
4474	}
4475	ext4_fc_track_range(handle, inode, start: start_lblk, end: end_lblk);
4476
4477	ret = ext4_mark_inode_dirty(handle, inode);
4478	if (unlikely(ret))
4479	goto out_handle;
4480
4481	ext4_update_inode_fsync_trans(handle, inode, datasync: `1`);
4482	if (IS_SYNC(inode))
4483	ext4_handle_sync(handle);
4484	out_handle:
4485	ext4_journal_stop(handle);
4486	return ret;
4487	}
4488
4489	int ext4_inode_attach_jinode(struct inode *inode)
4490	{
4491	struct ext4_inode_info *ei = EXT4_I(inode);
4492	struct jbd2_inode *jinode;
4493
4494	if (ei->jinode \|\| !EXT4_SB(sb: inode->i_sb)->s_journal)
4495	return `0`;
4496
4497	jinode = jbd2_alloc_inode(GFP_KERNEL);
4498	spin_lock(lock: &inode->i_lock);
4499	if (!ei->jinode) {
4500	if (!jinode) {
4501	spin_unlock(lock: &inode->i_lock);
4502	return -ENOMEM;
4503	}
4504	ei->jinode = jinode;
4505	jbd2_journal_init_jbd_inode(jinode: ei->jinode, inode);
4506	jinode = NULL;
4507	}
4508	spin_unlock(lock: &inode->i_lock);
4509	if (unlikely(jinode != NULL))
4510	jbd2_free_inode(jinode);
4511	return `0`;
4512	}
4513
4514	/*
4515	* ext4_truncate()
4516	*
4517	* We block out ext4_get_block() block instantiations across the entire
4518	* transaction, and VFS/VM ensures that ext4_truncate() cannot run
4519	* simultaneously on behalf of the same inode.
4520	*
4521	* As we work through the truncate and commit bits of it to the journal there
4522	* is one core, guiding principle: the file's tree must always be consistent on
4523	* disk. We must be able to restart the truncate after a crash.
4524	*
4525	* The file's tree may be transiently inconsistent in memory (although it
4526	* probably isn't), but whenever we close off and commit a journal transaction,
4527	* the contents of (the filesystem + the journal) must be consistent and
4528	* restartable. It's pretty simple, really: bottom up, right to left (although
4529	* left-to-right works OK too).
4530	*
4531	* Note that at recovery time, journal replay occurs before the restart of
4532	* truncate against the orphan inode list.
4533	*
4534	* The committed inode has the new, desired i_size (which is the same as
4535	* i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
4536	* that this inode's truncate did not complete and it will again call
4537	* ext4_truncate() to have another go. So there will be instantiated blocks
4538	* to the right of the truncation point in a crashed ext4 filesystem. But
4539	* that's fine - as long as they are linked from the inode, the post-crash
4540	* ext4_truncate() run will find them and release them.
4541	*/
4542	int ext4_truncate(struct inode *inode)
4543	{
4544	struct ext4_inode_info *ei = EXT4_I(inode);
4545	unsigned int credits;
4546	int err = `0`, err2;
4547	handle_t *handle;
4548	struct address_space *mapping = inode->i_mapping;
4549
4550	/*
4551	* There is a possibility that we're either freeing the inode
4552	* or it's a completely new inode. In those cases we might not
4553	* have i_rwsem locked because it's not necessary.
4554	*/
4555	if (!(inode->i_state & (I_NEW\|I_FREEING)))
4556	WARN_ON(!inode_is_locked(inode));
4557	trace_ext4_truncate_enter(inode);
4558
4559	if (!ext4_can_truncate(inode))
4560	goto out_trace;
4561
4562	if (inode->i_size == `0` && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4563	ext4_set_inode_state(inode, bit: EXT4_STATE_DA_ALLOC_CLOSE);
4564
4565	if (ext4_has_inline_data(inode)) {
4566	int has_inline = `1`;
4567
4568	err = ext4_inline_data_truncate(inode, has_inline: &has_inline);
4569	if (err \|\| has_inline)
4570	goto out_trace;
4571	}
4572
4573	/ If we zero-out tail of the page, we have to create jinode for jbd2 /
4574	if (inode->i_size & (inode->i_sb->s_blocksize - `1`)) {
4575	err = ext4_inode_attach_jinode(inode);
4576	if (err)
4577	goto out_trace;
4578	}
4579
4580	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
4581	credits = ext4_chunk_trans_extent(inode, nrblocks: `1`);
4582	else
4583	credits = ext4_blocks_for_truncate(inode);
4584
4585	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4586	if (IS_ERR(ptr: handle)) {
4587	err = PTR_ERR(ptr: handle);
4588	goto out_trace;
4589	}
4590
4591	if (inode->i_size & (inode->i_sb->s_blocksize - `1`))
4592	ext4_block_truncate_page(handle, mapping, from: inode->i_size);
4593
4594	/*
4595	* We add the inode to the orphan list, so that if this
4596	* truncate spans multiple transactions, and we crash, we will
4597	* resume the truncate when the filesystem recovers. It also
4598	* marks the inode dirty, to catch the new size.
4599	*
4600	* Implication: the file must always be in a sane, consistent
4601	* truncatable state while each transaction commits.
4602	*/
4603	err = ext4_orphan_add(handle, inode);
4604	if (err)
4605	goto out_stop;
4606
4607	ext4_fc_track_inode(handle, inode);
4608	ext4_check_map_extents_env(inode);
4609
4610	down_write(sem: &EXT4_I(inode)->i_data_sem);
4611	ext4_discard_preallocations(inode);
4612
4613	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
4614	err = ext4_ext_truncate(handle, inode);
4615	else
4616	ext4_ind_truncate(handle, inode);
4617
4618	up_write(sem: &ei->i_data_sem);
4619	if (err)
4620	goto out_stop;
4621
4622	if (IS_SYNC(inode))
4623	ext4_handle_sync(handle);
4624
4625	out_stop:
4626	/*
4627	* If this was a simple ftruncate() and the file will remain alive,
4628	* then we need to clear up the orphan record which we created above.
4629	* However, if this was a real unlink then we were called by
4630	* ext4_evict_inode(), and we allow that function to clean up the
4631	* orphan info for us.
4632	*/
4633	if (inode->i_nlink)
4634	ext4_orphan_del(handle, inode);
4635
4636	inode_set_mtime_to_ts(inode, ts: inode_set_ctime_current(inode));
4637	err2 = ext4_mark_inode_dirty(handle, inode);
4638	if (unlikely(err2 && !err))
4639	err = err2;
4640	ext4_journal_stop(handle);
4641
4642	out_trace:
4643	trace_ext4_truncate_exit(inode);
4644	return err;
4645	}
4646
4647	static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4648	{
4649	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4650	return inode_peek_iversion_raw(inode);
4651	else
4652	return inode_peek_iversion(inode);
4653	}
4654
4655	static int ext4_inode_blocks_set(struct ext4_inode *raw_inode,
4656	struct ext4_inode_info *ei)
4657	{
4658	struct inode *inode = &(ei->vfs_inode);
4659	u64 i_blocks = READ_ONCE(inode->i_blocks);
4660	struct super_block *sb = inode->i_sb;
4661
4662	if (i_blocks <= ~`0U`) {
4663	/*
4664	* i_blocks can be represented in a 32 bit variable
4665	* as multiple of 512 bytes
4666	*/
4667	raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4668	raw_inode->i_blocks_high = `0`;
4669	ext4_clear_inode_flag(inode, bit: EXT4_INODE_HUGE_FILE);
4670	return `0`;
4671	}
4672
4673	/*
4674	* This should never happen since sb->s_maxbytes should not have
4675	* allowed this, sb->s_maxbytes was set according to the huge_file
4676	* feature in ext4_fill_super().
4677	*/
4678	if (!ext4_has_feature_huge_file(sb))
4679	return -EFSCORRUPTED;
4680
4681	if (i_blocks <= `0xffffffffffffULL`) {
4682	/*
4683	* i_blocks can be represented in a 48 bit variable
4684	* as multiple of 512 bytes
4685	*/
4686	raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4687	raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> `32`);
4688	ext4_clear_inode_flag(inode, bit: EXT4_INODE_HUGE_FILE);
4689	} else {
4690	ext4_set_inode_flag(inode, bit: EXT4_INODE_HUGE_FILE);
4691	/ i_block is stored in file system block size /
4692	i_blocks = i_blocks >> (inode->i_blkbits - `9`);
4693	raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
4694	raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> `32`);
4695	}
4696	return `0`;
4697	}
4698
4699	static int ext4_fill_raw_inode(struct inode inode, struct* ext4_inode *raw_inode)
4700	{
4701	struct ext4_inode_info *ei = EXT4_I(inode);
4702	uid_t i_uid;
4703	gid_t i_gid;
4704	projid_t i_projid;
4705	int block;
4706	int err;
4707
4708	err = ext4_inode_blocks_set(raw_inode, ei);
4709
4710	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4711	i_uid = i_uid_read(inode);
4712	i_gid = i_gid_read(inode);
4713	i_projid = from_kprojid(to: &init_user_ns, kprojid: ei->i_projid);
4714	if (!(test_opt(inode->i_sb, NO_UID32))) {
4715	raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4716	raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4717	/*
4718	* Fix up interoperability with old kernels. Otherwise,
4719	* old inodes get re-used with the upper 16 bits of the
4720	* uid/gid intact.
4721	*/
4722	if (ei->i_dtime && !ext4_inode_orphan_tracked(inode)) {
4723	raw_inode->i_uid_high = `0`;
4724	raw_inode->i_gid_high = `0`;
4725	} else {
4726	raw_inode->i_uid_high =
4727	cpu_to_le16(high_16_bits(i_uid));
4728	raw_inode->i_gid_high =
4729	cpu_to_le16(high_16_bits(i_gid));
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_CTIME(inode, raw_inode);
4740	EXT4_INODE_SET_MTIME(inode, raw_inode);
4741	EXT4_INODE_SET_ATIME(inode, raw_inode);
4742	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4743
4744	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4745	raw_inode->i_flags = cpu_to_le32(ei->i_flags & `0xFFFFFFFF`);
4746	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4747	raw_inode->i_file_acl_high =
4748	cpu_to_le16(ei->i_file_acl >> `32`);
4749	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4750	ext4_isize_set(raw_inode, i_size: ei->i_disksize);
4751
4752	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4753	if (S_ISCHR(inode->i_mode) \|\| S_ISBLK(inode->i_mode)) {
4754	if (old_valid_dev(dev: inode->i_rdev)) {
4755	raw_inode->i_block[`0`] =
4756	cpu_to_le32(old_encode_dev(inode->i_rdev));
4757	raw_inode->i_block[`1`] = `0`;
4758	} else {
4759	raw_inode->i_block[`0`] = `0`;
4760	raw_inode->i_block[`1`] =
4761	cpu_to_le32(new_encode_dev(inode->i_rdev));
4762	raw_inode->i_block[`2`] = `0`;
4763	}
4764	} else if (!ext4_has_inline_data(inode)) {
4765	for (block = `0`; block < EXT4_N_BLOCKS; block++)
4766	raw_inode->i_block[block] = ei->i_data[block];
4767	}
4768
4769	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4770	u64 ivers = ext4_inode_peek_iversion(inode);
4771
4772	raw_inode->i_disk_version = cpu_to_le32(ivers);
4773	if (ei->i_extra_isize) {
4774	if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4775	raw_inode->i_version_hi =
4776	cpu_to_le32(ivers >> `32`);
4777	raw_inode->i_extra_isize =
4778	cpu_to_le16(ei->i_extra_isize);
4779	}
4780	}
4781
4782	if (i_projid != EXT4_DEF_PROJID &&
4783	!ext4_has_feature_project(sb: inode->i_sb))
4784	err = err ?: -EFSCORRUPTED;
4785
4786	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4787	EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4788	raw_inode->i_projid = cpu_to_le32(i_projid);
4789
4790	ext4_inode_csum_set(inode, raw: raw_inode, ei);
4791	return err;
4792	}
4793
4794	/*
4795	* ext4_get_inode_loc returns with an extra refcount against the inode's
4796	* underlying buffer_head on success. If we pass 'inode' and it does not
4797	* have in-inode xattr, we have all inode data in memory that is needed
4798	* to recreate the on-disk version of this inode.
4799	*/
4800	static int __ext4_get_inode_loc(struct super_block sb, unsigned* long ino,
4801	struct inode inode, struct* ext4_iloc *iloc,
4802	ext4_fsblk_t *ret_block)
4803	{
4804	struct ext4_group_desc *gdp;
4805	struct buffer_head *bh;
4806	ext4_fsblk_t block;
4807	struct blk_plug plug;
4808	int inodes_per_block, inode_offset;
4809
4810	iloc->bh = NULL;
4811	if (ino < EXT4_ROOT_INO \|\|
4812	ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4813	return -EFSCORRUPTED;
4814
4815	iloc->block_group = (ino - `1`) / EXT4_INODES_PER_GROUP(sb);
4816	gdp = ext4_get_group_desc(sb, block_group: iloc->block_group, NULL);
4817	if (!gdp)
4818	return -EIO;
4819
4820	/*
4821	* Figure out the offset within the block group inode table
4822	*/
4823	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4824	inode_offset = ((ino - `1`) %
4825	EXT4_INODES_PER_GROUP(sb));
4826	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4827
4828	block = ext4_inode_table(sb, bg: gdp);
4829	if ((block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) \|\|
4830	(block >= ext4_blocks_count(es: EXT4_SB(sb)->s_es))) {
4831	ext4_error(sb, "Invalid inode table block %llu in "
4832	"block_group %u", block, iloc->block_group);
4833	return -EFSCORRUPTED;
4834	}
4835	block += (inode_offset / inodes_per_block);
4836
4837	bh = sb_getblk(sb, block);
4838	if (unlikely(!bh))
4839	return -ENOMEM;
4840	if (ext4_buffer_uptodate(bh))
4841	goto has_buffer;
4842
4843	lock_buffer(bh);
4844	if (ext4_buffer_uptodate(bh)) {
4845	/ Someone brought it uptodate while we waited /
4846	unlock_buffer(bh);
4847	goto has_buffer;
4848	}
4849
4850	/*
4851	* If we have all information of the inode in memory and this
4852	* is the only valid inode in the block, we need not read the
4853	* block.
4854	*/
4855	if (inode && !ext4_test_inode_state(inode, bit: EXT4_STATE_XATTR)) {
4856	struct buffer_head *bitmap_bh;
4857	int i, start;
4858
4859	start = inode_offset & ~(inodes_per_block - `1`);
4860
4861	/ Is the inode bitmap in cache? /
4862	bitmap_bh = sb_getblk(sb, block: ext4_inode_bitmap(sb, bg: gdp));
4863	if (unlikely(!bitmap_bh))
4864	goto make_io;
4865
4866	/*
4867	* If the inode bitmap isn't in cache then the
4868	* optimisation may end up performing two reads instead
4869	* of one, so skip it.
4870	*/
4871	if (!buffer_uptodate(bh: bitmap_bh)) {
4872	brelse(bh: bitmap_bh);
4873	goto make_io;
4874	}
4875	for (i = start; i < start + inodes_per_block; i++) {
4876	if (i == inode_offset)
4877	continue;
4878	if (ext4_test_bit(nr: i, addr: bitmap_bh->b_data))
4879	break;
4880	}
4881	brelse(bh: bitmap_bh);
4882	if (i == start + inodes_per_block) {
4883	struct ext4_inode *raw_inode =
4884	(struct ext4_inode *) (bh->b_data + iloc->offset);
4885
4886	/ all other inodes are free, so skip I/O /
4887	memset(s: bh->b_data, c: `0`, n: bh->b_size);
4888	if (!ext4_test_inode_state(inode, bit: EXT4_STATE_NEW))
4889	ext4_fill_raw_inode(inode, raw_inode);
4890	set_buffer_uptodate(bh);
4891	unlock_buffer(bh);
4892	goto has_buffer;
4893	}
4894	}
4895
4896	make_io:
4897	/*
4898	* If we need to do any I/O, try to pre-readahead extra
4899	* blocks from the inode table.
4900	*/
4901	blk_start_plug(&plug);
4902	if (EXT4_SB(sb)->s_inode_readahead_blks) {
4903	ext4_fsblk_t b, end, table;
4904	unsigned num;
4905	__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4906
4907	table = ext4_inode_table(sb, bg: gdp);
4908	/ s_inode_readahead_blks is always a power of 2 /
4909	b = block & ~((ext4_fsblk_t) ra_blks - `1`);
4910	if (table > b)
4911	b = table;
4912	end = b + ra_blks;
4913	num = EXT4_INODES_PER_GROUP(sb);
4914	if (ext4_has_group_desc_csum(sb))
4915	num -= ext4_itable_unused_count(sb, bg: gdp);
4916	table += num / inodes_per_block;
4917	if (end > table)
4918	end = table;
4919	while (b <= end)
4920	ext4_sb_breadahead_unmovable(sb, block: b++);
4921	}
4922
4923	/*
4924	* There are other valid inodes in the buffer, this inode
4925	* has in-inode xattrs, or we don't have this inode in memory.
4926	* Read the block from disk.
4927	*/
4928	trace_ext4_load_inode(sb, ino);
4929	ext4_read_bh_nowait(bh, REQ_META \| REQ_PRIO, NULL,
4930	simu_fail: ext4_simulate_fail(sb, EXT4_SIM_INODE_EIO));
4931	blk_finish_plug(&plug);
4932	wait_on_buffer(bh);
4933	if (!buffer_uptodate(bh)) {
4934	if (ret_block)
4935	*ret_block = block;
4936	brelse(bh);
4937	return -EIO;
4938	}
4939	has_buffer:
4940	iloc->bh = bh;
4941	return `0`;
4942	}
4943
4944	static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4945	struct ext4_iloc *iloc)
4946	{
4947	ext4_fsblk_t err_blk = `0`;
4948	int ret;
4949
4950	ret = __ext4_get_inode_loc(sb: inode->i_sb, ino: inode->i_ino, NULL, iloc,
4951	ret_block: &err_blk);
4952
4953	if (ret == -EIO)
4954	ext4_error_inode_block(inode, err_blk, EIO,
4955	"unable to read itable block");
4956
4957	return ret;
4958	}
4959
4960	int ext4_get_inode_loc(struct inode inode, struct* ext4_iloc *iloc)
4961	{
4962	ext4_fsblk_t err_blk = `0`;
4963	int ret;
4964
4965	ret = __ext4_get_inode_loc(sb: inode->i_sb, ino: inode->i_ino, inode, iloc,
4966	ret_block: &err_blk);
4967
4968	if (ret == -EIO)
4969	ext4_error_inode_block(inode, err_blk, EIO,
4970	"unable to read itable block");
4971
4972	return ret;
4973	}
4974
4975
4976	int ext4_get_fc_inode_loc(struct super_block sb, unsigned* long ino,
4977	struct ext4_iloc *iloc)
4978	{
4979	return __ext4_get_inode_loc(sb, ino, NULL, iloc, NULL);
4980	}
4981
4982	static bool ext4_should_enable_dax(struct inode *inode)
4983	{
4984	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
4985
4986	if (test_opt2(inode->i_sb, DAX_NEVER))
4987	return false;
4988	if (!S_ISREG(inode->i_mode))
4989	return false;
4990	if (ext4_should_journal_data(inode))
4991	return false;
4992	if (ext4_has_inline_data(inode))
4993	return false;
4994	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_ENCRYPT))
4995	return false;
4996	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_VERITY))
4997	return false;
4998	if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4999	return false;
5000	if (test_opt(inode->i_sb, DAX_ALWAYS))
5001	return true;
5002
5003	return ext4_test_inode_flag(inode, bit: EXT4_INODE_DAX);
5004	}
5005
5006	void ext4_set_inode_flags(struct inode *inode, bool init)
5007	{
5008	unsigned int flags = EXT4_I(inode)->i_flags;
5009	unsigned int new_fl = `0`;
5010
5011	WARN_ON_ONCE(IS_DAX(inode) && init);
5012
5013	if (flags & EXT4_SYNC_FL)
5014	new_fl \|= S_SYNC;
5015	if (flags & EXT4_APPEND_FL)
5016	new_fl \|= S_APPEND;
5017	if (flags & EXT4_IMMUTABLE_FL)
5018	new_fl \|= S_IMMUTABLE;
5019	if (flags & EXT4_NOATIME_FL)
5020	new_fl \|= S_NOATIME;
5021	if (flags & EXT4_DIRSYNC_FL)
5022	new_fl \|= S_DIRSYNC;
5023
5024	/ Because of the way inode_set_flags() works we must preserve S_DAX*
5025	* here if already set. */
5026	new_fl \|= (inode->i_flags & S_DAX);
5027	if (init && ext4_should_enable_dax(inode))
5028	new_fl \|= S_DAX;
5029
5030	if (flags & EXT4_ENCRYPT_FL)
5031	new_fl \|= S_ENCRYPTED;
5032	if (flags & EXT4_CASEFOLD_FL)
5033	new_fl \|= S_CASEFOLD;
5034	if (flags & EXT4_VERITY_FL)
5035	new_fl \|= S_VERITY;
5036	inode_set_flags(inode, flags: new_fl,
5037	S_SYNC\|S_APPEND\|S_IMMUTABLE\|S_NOATIME\|S_DIRSYNC\|S_DAX\|
5038	S_ENCRYPTED\|S_CASEFOLD\|S_VERITY);
5039	}
5040
5041	static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
5042	struct ext4_inode_info *ei)
5043	{
5044	blkcnt_t i_blocks ;
5045	struct inode *inode = &(ei->vfs_inode);
5046	struct super_block *sb = inode->i_sb;
5047
5048	if (ext4_has_feature_huge_file(sb)) {
5049	/ we are using combined 48 bit field /
5050	i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << `32` \|
5051	le32_to_cpu(raw_inode->i_blocks_lo);
5052	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_HUGE_FILE)) {
5053	/ i_blocks represent file system block size /
5054	return i_blocks << (inode->i_blkbits - `9`);
5055	} else {
5056	return i_blocks;
5057	}
5058	} else {
5059	return le32_to_cpu(raw_inode->i_blocks_lo);
5060	}
5061	}
5062
5063	static inline int ext4_iget_extra_inode(struct inode *inode,
5064	struct ext4_inode *raw_inode,
5065	struct ext4_inode_info *ei)
5066	{
5067	__le32 magic = (void* *)raw_inode +
5068	EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
5069
5070	if (EXT4_INODE_HAS_XATTR_SPACE(inode) &&
5071	*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
5072	int err;
5073
5074	err = xattr_check_inode(inode, IHDR(inode, raw_inode),
5075	ITAIL(inode, raw_inode));
5076	if (err)
5077	return err;
5078
5079	ext4_set_inode_state(inode, bit: EXT4_STATE_XATTR);
5080	err = ext4_find_inline_data_nolock(inode);
5081	if (!err && ext4_has_inline_data(inode))
5082	ext4_set_inode_state(inode, bit: EXT4_STATE_MAY_INLINE_DATA);
5083	return err;
5084	} else
5085	EXT4_I(inode)->i_inline_off = `0`;
5086	return `0`;
5087	}
5088
5089	int ext4_get_projid(struct inode inode, kprojid_t projid)
5090	{
5091	if (!ext4_has_feature_project(sb: inode->i_sb))
5092	return -EOPNOTSUPP;
5093	*projid = EXT4_I(inode)->i_projid;
5094	return `0`;
5095	}
5096
5097	/*
5098	* ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
5099	* refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
5100	* set.
5101	*/
5102	static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
5103	{
5104	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
5105	inode_set_iversion_raw(inode, val);
5106	else
5107	inode_set_iversion_queried(inode, val);
5108	}
5109
5110	static int check_igot_inode(struct inode *inode, ext4_iget_flags flags,
5111	const char function, unsigned* int line)
5112	{
5113	const char *err_str;
5114
5115	if (flags & EXT4_IGET_EA_INODE) {
5116	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
5117	err_str = "missing EA_INODE flag";
5118	goto error;
5119	}
5120	if (ext4_test_inode_state(inode, bit: EXT4_STATE_XATTR) \|\|
5121	EXT4_I(inode)->i_file_acl) {
5122	err_str = "ea_inode with extended attributes";
5123	goto error;
5124	}
5125	} else {
5126	if ((EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
5127	/*
5128	* open_by_handle_at() could provide an old inode number
5129	* that has since been reused for an ea_inode; this does
5130	* not indicate filesystem corruption
5131	*/
5132	if (flags & EXT4_IGET_HANDLE)
5133	return -ESTALE;
5134	err_str = "unexpected EA_INODE flag";
5135	goto error;
5136	}
5137	}
5138	if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD)) {
5139	err_str = "unexpected bad inode w/o EXT4_IGET_BAD";
5140	goto error;
5141	}
5142	return `0`;
5143
5144	error:
5145	ext4_error_inode(inode, function, line, `0`, "%s", err_str);
5146	return -EFSCORRUPTED;
5147	}
5148
5149	static bool ext4_should_enable_large_folio(struct inode *inode)
5150	{
5151	struct super_block *sb = inode->i_sb;
5152
5153	if (!S_ISREG(inode->i_mode))
5154	return false;
5155	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA \|\|
5156	ext4_test_inode_flag(inode, bit: EXT4_INODE_JOURNAL_DATA))
5157	return false;
5158	if (ext4_has_feature_verity(sb))
5159	return false;
5160	if (ext4_has_feature_encrypt(sb))
5161	return false;
5162
5163	return true;
5164	}
5165
5166	/*
5167	* Limit the maximum folio order to 2048 blocks to prevent overestimation
5168	* of reserve handle credits during the folio writeback in environments
5169	* where the PAGE_SIZE exceeds 4KB.
5170	*/
5171	#define EXT4_MAX_PAGECACHE_ORDER(i) \
5172	umin(MAX_PAGECACHE_ORDER, (11 + (i)->i_blkbits - PAGE_SHIFT))
5173	void ext4_set_inode_mapping_order(struct inode *inode)
5174	{
5175	if (!ext4_should_enable_large_folio(inode))
5176	return;
5177
5178	mapping_set_folio_order_range(mapping: inode->i_mapping, min: `0`,
5179	EXT4_MAX_PAGECACHE_ORDER(inode));
5180	}
5181
5182	struct inode __ext4_iget(struct* super_block sb, unsigned* long ino,
5183	ext4_iget_flags flags, const char *function,
5184	unsigned int line)
5185	{
5186	struct ext4_iloc iloc;
5187	struct ext4_inode *raw_inode;
5188	struct ext4_inode_info *ei;
5189	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
5190	struct inode *inode;
5191	journal_t *journal = EXT4_SB(sb)->s_journal;
5192	long ret;
5193	loff_t size;
5194	int block;
5195	uid_t i_uid;
5196	gid_t i_gid;
5197	projid_t i_projid;
5198
5199	if ((!(flags & EXT4_IGET_SPECIAL) && is_special_ino(sb, ino)) \|\|
5200	(ino < EXT4_ROOT_INO) \|\|
5201	(ino > le32_to_cpu(es->s_inodes_count))) {
5202	if (flags & EXT4_IGET_HANDLE)
5203	return ERR_PTR(error: -ESTALE);
5204	__ext4_error(sb, function, line, false, EFSCORRUPTED, `0`,
5205	"inode #%lu: comm %s: iget: illegal inode #",
5206	ino, current->comm);
5207	return ERR_PTR(error: -EFSCORRUPTED);
5208	}
5209
5210	inode = iget_locked(sb, ino);
5211	if (!inode)
5212	return ERR_PTR(error: -ENOMEM);
5213	if (!(inode->i_state & I_NEW)) {
5214	ret = check_igot_inode(inode, flags, function, line);
5215	if (ret) {
5216	iput(inode);
5217	return ERR_PTR(error: ret);
5218	}
5219	return inode;
5220	}
5221
5222	ei = EXT4_I(inode);
5223	iloc.bh = NULL;
5224
5225	ret = __ext4_get_inode_loc_noinmem(inode, iloc: &iloc);
5226	if (ret < `0`)
5227	goto bad_inode;
5228	raw_inode = ext4_raw_inode(iloc: &iloc);
5229
5230	if ((flags & EXT4_IGET_HANDLE) &&
5231	(raw_inode->i_links_count == `0`) && (raw_inode->i_mode == `0`)) {
5232	ret = -ESTALE;
5233	goto bad_inode;
5234	}
5235
5236	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
5237	ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
5238	if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
5239	EXT4_INODE_SIZE(inode->i_sb) \|\|
5240	(ei->i_extra_isize & `3`)) {
5241	ext4_error_inode(inode, function, line, `0`,
5242	"iget: bad extra_isize %u "
5243	"(inode size %u)",
5244	ei->i_extra_isize,
5245	EXT4_INODE_SIZE(inode->i_sb));
5246	ret = -EFSCORRUPTED;
5247	goto bad_inode;
5248	}
5249	} else
5250	ei->i_extra_isize = `0`;
5251
5252	/ Precompute checksum seed for inode metadata /
5253	if (ext4_has_feature_metadata_csum(sb)) {
5254	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
5255	__u32 csum;
5256	__le32 inum = cpu_to_le32(inode->i_ino);
5257	__le32 gen = raw_inode->i_generation;
5258	csum = ext4_chksum(crc: sbi->s_csum_seed, address: (__u8 *)&inum,
5259	length: sizeof(inum));
5260	ei->i_csum_seed = ext4_chksum(crc: csum, address: (__u8 )&gen, length: sizeof*(gen));
5261	}
5262
5263	if ((!ext4_inode_csum_verify(inode, raw: raw_inode, ei) \|\|
5264	ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
5265	(!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
5266	ext4_error_inode_err(inode, function, line, `0`,
5267	EFSBADCRC, "iget: checksum invalid");
5268	ret = -EFSBADCRC;
5269	goto bad_inode;
5270	}
5271
5272	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
5273	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
5274	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
5275	if (ext4_has_feature_project(sb) &&
5276	EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
5277	EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
5278	i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
5279	else
5280	i_projid = EXT4_DEF_PROJID;
5281
5282	if (!(test_opt(inode->i_sb, NO_UID32))) {
5283	i_uid \|= le16_to_cpu(raw_inode->i_uid_high) << `16`;
5284	i_gid \|= le16_to_cpu(raw_inode->i_gid_high) << `16`;
5285	}
5286	i_uid_write(inode, uid: i_uid);
5287	i_gid_write(inode, gid: i_gid);
5288	ei->i_projid = make_kprojid(from: &init_user_ns, projid: i_projid);
5289	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
5290
5291	ext4_clear_state_flags(ei); / Only relevant on 32-bit archs /
5292	ei->i_inline_off = `0`;
5293	ei->i_dir_start_lookup = `0`;
5294	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
5295	/ We now have enough fields to check if the inode was active or not.*
5296	* This is needed because nfsd might try to access dead inodes
5297	* the test is that same one that e2fsck uses
5298	* NeilBrown 1999oct15
5299	*/
5300	if (inode->i_nlink == `0`) {
5301	if ((inode->i_mode == `0` \|\| flags & EXT4_IGET_SPECIAL \|\|
5302	!(EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
5303	ino != EXT4_BOOT_LOADER_INO) {
5304	/ this inode is deleted or unallocated /
5305	if (flags & EXT4_IGET_SPECIAL) {
5306	ext4_error_inode(inode, function, line, `0`,
5307	"iget: special inode unallocated");
5308	ret = -EFSCORRUPTED;
5309	} else
5310	ret = -ESTALE;
5311	goto bad_inode;
5312	}
5313	/ The only unlinked inodes we let through here have*
5314	* valid i_mode and are being read by the orphan
5315	* recovery code: that's fine, we're about to complete
5316	* the process of deleting those.
5317	* OR it is the EXT4_BOOT_LOADER_INO which is
5318	* not initialized on a new filesystem. */
5319	}
5320	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
5321	ext4_set_inode_flags(inode, init: true);
5322	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
5323	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
5324	if (ext4_has_feature_64bit(sb))
5325	ei->i_file_acl \|=
5326	((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << `32`;
5327	inode->i_size = ext4_isize(sb, raw_inode);
5328	size = i_size_read(inode);
5329	if (size < `0` \|\| size > ext4_get_maxbytes(inode)) {
5330	ext4_error_inode(inode, function, line, `0`,
5331	"iget: bad i_size value: %lld", size);
5332	ret = -EFSCORRUPTED;
5333	goto bad_inode;
5334	}
5335	/*
5336	* If dir_index is not enabled but there's dir with INDEX flag set,
5337	* we'd normally treat htree data as empty space. But with metadata
5338	* checksumming that corrupts checksums so forbid that.
5339	*/
5340	if (!ext4_has_feature_dir_index(sb) &&
5341	ext4_has_feature_metadata_csum(sb) &&
5342	ext4_test_inode_flag(inode, bit: EXT4_INODE_INDEX)) {
5343	ext4_error_inode(inode, function, line, `0`,
5344	"iget: Dir with htree data on filesystem without dir_index feature.");
5345	ret = -EFSCORRUPTED;
5346	goto bad_inode;
5347	}
5348	ei->i_disksize = inode->i_size;
5349	#ifdef CONFIG_QUOTA
5350	ei->i_reserved_quota = `0`;
5351	#endif
5352	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
5353	ei->i_block_group = iloc.block_group;
5354	ei->i_last_alloc_group = ~`0`;
5355	/*
5356	* NOTE! The in-memory inode i_data array is in little-endian order
5357	* even on big-endian machines: we do NOT byteswap the block numbers!
5358	*/
5359	for (block = `0`; block < EXT4_N_BLOCKS; block++)
5360	ei->i_data[block] = raw_inode->i_block[block];
5361	INIT_LIST_HEAD(list: &ei->i_orphan);
5362	ext4_fc_init_inode(inode: &ei->vfs_inode);
5363
5364	/*
5365	* Set transaction id's of transactions that have to be committed
5366	* to finish f[data]sync. We set them to currently running transaction
5367	* as we cannot be sure that the inode or some of its metadata isn't
5368	* part of the transaction - the inode could have been reclaimed and
5369	* now it is reread from disk.
5370	*/
5371	if (journal) {
5372	transaction_t *transaction;
5373	tid_t tid;
5374
5375	read_lock(&journal->j_state_lock);
5376	if (journal->j_running_transaction)
5377	transaction = journal->j_running_transaction;
5378	else
5379	transaction = journal->j_committing_transaction;
5380	if (transaction)
5381	tid = transaction->t_tid;
5382	else
5383	tid = journal->j_commit_sequence;
5384	read_unlock(&journal->j_state_lock);
5385	ei->i_sync_tid = tid;
5386	ei->i_datasync_tid = tid;
5387	}
5388
5389	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
5390	if (ei->i_extra_isize == `0`) {
5391	/ The extra space is currently unused. Use it. /
5392	BUILD_BUG_ON(sizeof(struct ext4_inode) & `3`);
5393	ei->i_extra_isize = sizeof(struct ext4_inode) -
5394	EXT4_GOOD_OLD_INODE_SIZE;
5395	} else {
5396	ret = ext4_iget_extra_inode(inode, raw_inode, ei);
5397	if (ret)
5398	goto bad_inode;
5399	}
5400	}
5401
5402	EXT4_INODE_GET_CTIME(inode, raw_inode);
5403	EXT4_INODE_GET_ATIME(inode, raw_inode);
5404	EXT4_INODE_GET_MTIME(inode, raw_inode);
5405	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
5406
5407	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
5408	u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
5409
5410	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
5411	if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5412	ivers \|=
5413	(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << `32`;
5414	}
5415	ext4_inode_set_iversion_queried(inode, val: ivers);
5416	}
5417
5418	ret = `0`;
5419	if (ei->i_file_acl &&
5420	!ext4_inode_block_valid(inode, start_blk: ei->i_file_acl, count: `1`)) {
5421	ext4_error_inode(inode, function, line, `0`,
5422	"iget: bad extended attribute block %llu",
5423	ei->i_file_acl);
5424	ret = -EFSCORRUPTED;
5425	goto bad_inode;
5426	} else if (!ext4_has_inline_data(inode)) {
5427	/ validate the block references in the inode /
5428	if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
5429	(S_ISREG(inode->i_mode) \|\| S_ISDIR(inode->i_mode) \|\|
5430	(S_ISLNK(inode->i_mode) &&
5431	!ext4_inode_is_fast_symlink(inode)))) {
5432	if (ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))
5433	ret = ext4_ext_check_inode(inode);
5434	else
5435	ret = ext4_ind_check_inode(inode);
5436	}
5437	}
5438	if (ret)
5439	goto bad_inode;
5440
5441	if (S_ISREG(inode->i_mode)) {
5442	inode->i_op = &ext4_file_inode_operations;
5443	inode->i_fop = &ext4_file_operations;
5444	ext4_set_aops(inode);
5445	} else if (S_ISDIR(inode->i_mode)) {
5446	inode->i_op = &ext4_dir_inode_operations;
5447	inode->i_fop = &ext4_dir_operations;
5448	} else if (S_ISLNK(inode->i_mode)) {
5449	/ VFS does not allow setting these so must be corruption /
5450	if (IS_APPEND(inode) \|\| IS_IMMUTABLE(inode)) {
5451	ext4_error_inode(inode, function, line, `0`,
5452	"iget: immutable or append flags "
5453	"not allowed on symlinks");
5454	ret = -EFSCORRUPTED;
5455	goto bad_inode;
5456	}
5457	if (IS_ENCRYPTED(inode)) {
5458	inode->i_op = &ext4_encrypted_symlink_inode_operations;
5459	} else if (ext4_inode_is_fast_symlink(inode)) {
5460	inode->i_op = &ext4_fast_symlink_inode_operations;
5461	if (inode->i_size == `0` \|\|
5462	inode->i_size >= sizeof(ei->i_data) \|\|
5463	strnlen((char *)ei->i_data, inode->i_size + `1`) !=
5464	inode->i_size) {
5465	ext4_error_inode(inode, function, line, `0`,
5466	"invalid fast symlink length %llu",
5467	(unsigned long long)inode->i_size);
5468	ret = -EFSCORRUPTED;
5469	goto bad_inode;
5470	}
5471	inode_set_cached_link(inode, link: (char *)ei->i_data,
5472	linklen: inode->i_size);
5473	} else {
5474	inode->i_op = &ext4_symlink_inode_operations;
5475	}
5476	} else if (S_ISCHR(inode->i_mode) \|\| S_ISBLK(inode->i_mode) \|\|
5477	S_ISFIFO(inode->i_mode) \|\| S_ISSOCK(inode->i_mode)) {
5478	inode->i_op = &ext4_special_inode_operations;
5479	if (raw_inode->i_block[`0`])
5480	init_special_inode(inode, inode->i_mode,
5481	old_decode_dev(le32_to_cpu(raw_inode->i_block[`0`])));
5482	else
5483	init_special_inode(inode, inode->i_mode,
5484	new_decode_dev(le32_to_cpu(raw_inode->i_block[`1`])));
5485	} else if (ino == EXT4_BOOT_LOADER_INO) {
5486	make_bad_inode(inode);
5487	} else {
5488	ret = -EFSCORRUPTED;
5489	ext4_error_inode(inode, function, line, `0`,
5490	"iget: bogus i_mode (%o)", inode->i_mode);
5491	goto bad_inode;
5492	}
5493	if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(sb: inode->i_sb)) {
5494	ext4_error_inode(inode, function, line, `0`,
5495	"casefold flag without casefold feature");
5496	ret = -EFSCORRUPTED;
5497	goto bad_inode;
5498	}
5499
5500	ext4_set_inode_mapping_order(inode);
5501
5502	ret = check_igot_inode(inode, flags, function, line);
5503	/*
5504	* -ESTALE here means there is nothing inherently wrong with the inode,
5505	* it's just not an inode we can return for an fhandle lookup.
5506	*/
5507	if (ret == -ESTALE) {
5508	brelse(bh: iloc.bh);
5509	unlock_new_inode(inode);
5510	iput(inode);
5511	return ERR_PTR(error: -ESTALE);
5512	}
5513	if (ret)
5514	goto bad_inode;
5515	brelse(bh: iloc.bh);
5516
5517	unlock_new_inode(inode);
5518	return inode;
5519
5520	bad_inode:
5521	brelse(bh: iloc.bh);
5522	iget_failed(inode);
5523	return ERR_PTR(error: ret);
5524	}
5525
5526	static void __ext4_update_other_inode_time(struct super_block *sb,
5527	unsigned long orig_ino,
5528	unsigned long ino,
5529	struct ext4_inode *raw_inode)
5530	{
5531	struct inode *inode;
5532
5533	inode = find_inode_by_ino_rcu(sb, ino);
5534	if (!inode)
5535	return;
5536
5537	if (!inode_is_dirtytime_only(inode))
5538	return;
5539
5540	spin_lock(lock: &inode->i_lock);
5541	if (inode_is_dirtytime_only(inode)) {
5542	struct ext4_inode_info *ei = EXT4_I(inode);
5543
5544	inode->i_state &= ~I_DIRTY_TIME;
5545	spin_unlock(lock: &inode->i_lock);
5546
5547	spin_lock(lock: &ei->i_raw_lock);
5548	EXT4_INODE_SET_CTIME(inode, raw_inode);
5549	EXT4_INODE_SET_MTIME(inode, raw_inode);
5550	EXT4_INODE_SET_ATIME(inode, raw_inode);
5551	ext4_inode_csum_set(inode, raw: raw_inode, ei);
5552	spin_unlock(lock: &ei->i_raw_lock);
5553	trace_ext4_other_inode_update_time(inode, orig_ino);
5554	return;
5555	}
5556	spin_unlock(lock: &inode->i_lock);
5557	}
5558
5559	/*
5560	* Opportunistically update the other time fields for other inodes in
5561	* the same inode table block.
5562	*/
5563	static void ext4_update_other_inodes_time(struct super_block *sb,
5564	unsigned long orig_ino, char *buf)
5565	{
5566	unsigned long ino;
5567	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
5568	int inode_size = EXT4_INODE_SIZE(sb);
5569
5570	/*
5571	* Calculate the first inode in the inode table block. Inode
5572	* numbers are one-based. That is, the first inode in a block
5573	* (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
5574	*/
5575	ino = ((orig_ino - `1`) & ~(inodes_per_block - `1`)) + `1`;
5576	rcu_read_lock();
5577	for (i = `0`; i < inodes_per_block; i++, ino++, buf += inode_size) {
5578	if (ino == orig_ino)
5579	continue;
5580	__ext4_update_other_inode_time(sb, orig_ino, ino,
5581	raw_inode: (struct ext4_inode *)buf);
5582	}
5583	rcu_read_unlock();
5584	}
5585
5586	/*
5587	* Post the struct inode info into an on-disk inode location in the
5588	* buffer-cache. This gobbles the caller's reference to the
5589	* buffer_head in the inode location struct.
5590	*
5591	* The caller must have write access to iloc->bh.
5592	*/
5593	static int ext4_do_update_inode(handle_t *handle,
5594	struct inode *inode,
5595	struct ext4_iloc *iloc)
5596	{
5597	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5598	struct ext4_inode_info *ei = EXT4_I(inode);
5599	struct buffer_head *bh = iloc->bh;
5600	struct super_block *sb = inode->i_sb;
5601	int err;
5602	int need_datasync = `0`, set_large_file = `0`;
5603
5604	spin_lock(lock: &ei->i_raw_lock);
5605
5606	/*
5607	* For fields not tracked in the in-memory inode, initialise them
5608	* to zero for new inodes.
5609	*/
5610	if (ext4_test_inode_state(inode, bit: EXT4_STATE_NEW))
5611	memset(s: raw_inode, c: `0`, n: EXT4_SB(sb: inode->i_sb)->s_inode_size);
5612
5613	if (READ_ONCE(ei->i_disksize) != ext4_isize(sb: inode->i_sb, raw_inode))
5614	need_datasync = `1`;
5615	if (ei->i_disksize > `0x7fffffffULL`) {
5616	if (!ext4_has_feature_large_file(sb) \|\|
5617	EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV))
5618	set_large_file = `1`;
5619	}
5620
5621	err = ext4_fill_raw_inode(inode, raw_inode);
5622	spin_unlock(lock: &ei->i_raw_lock);
5623	if (err) {
5624	EXT4_ERROR_INODE(inode, "corrupted inode contents");
5625	goto out_brelse;
5626	}
5627
5628	if (inode->i_sb->s_flags & SB_LAZYTIME)
5629	ext4_update_other_inodes_time(sb: inode->i_sb, orig_ino: inode->i_ino,
5630	buf: bh->b_data);
5631
5632	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5633	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5634	if (err)
5635	goto out_error;
5636	ext4_clear_inode_state(inode, bit: EXT4_STATE_NEW);
5637	if (set_large_file) {
5638	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5639	err = ext4_journal_get_write_access(handle, sb,
5640	EXT4_SB(sb)->s_sbh,
5641	EXT4_JTR_NONE);
5642	if (err)
5643	goto out_error;
5644	lock_buffer(bh: EXT4_SB(sb)->s_sbh);
5645	ext4_set_feature_large_file(sb);
5646	ext4_superblock_csum_set(sb);
5647	unlock_buffer(bh: EXT4_SB(sb)->s_sbh);
5648	ext4_handle_sync(handle);
5649	err = ext4_handle_dirty_metadata(handle, NULL,
5650	EXT4_SB(sb)->s_sbh);
5651	}
5652	ext4_update_inode_fsync_trans(handle, inode, datasync: need_datasync);
5653	out_error:
5654	ext4_std_error(inode->i_sb, err);
5655	out_brelse:
5656	brelse(bh);
5657	return err;
5658	}
5659
5660	/*
5661	* ext4_write_inode()
5662	*
5663	* We are called from a few places:
5664	*
5665	* - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5666	* Here, there will be no transaction running. We wait for any running
5667	* transaction to commit.
5668	*
5669	* - Within flush work (sys_sync(), kupdate and such).
5670	* We wait on commit, if told to.
5671	*
5672	* - Within iput_final() -> write_inode_now()
5673	* We wait on commit, if told to.
5674	*
5675	* In all cases it is actually safe for us to return without doing anything,
5676	* because the inode has been copied into a raw inode buffer in
5677	* ext4_mark_inode_dirty(). This is a correctness thing for WB_SYNC_ALL
5678	* writeback.
5679	*
5680	* Note that we are absolutely dependent upon all inode dirtiers doing the
5681	* right thing: they must call mark_inode_dirty() after dirtying info in
5682	* which we are interested.
5683	*
5684	* It would be a bug for them to not do this. The code:
5685	*
5686	* mark_inode_dirty(inode)
5687	* stuff();
5688	* inode->i_size = expr;
5689	*
5690	* is in error because write_inode() could occur while `stuff()' is running,
5691	* and the new i_size will be lost. Plus the inode will no longer be on the
5692	* superblock's dirty inode list.
5693	*/
5694	int ext4_write_inode(struct inode inode, struct* writeback_control *wbc)
5695	{
5696	int err;
5697
5698	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
5699	return `0`;
5700
5701	err = ext4_emergency_state(sb: inode->i_sb);
5702	if (unlikely(err))
5703	return err;
5704
5705	if (EXT4_SB(sb: inode->i_sb)->s_journal) {
5706	if (ext4_journal_current_handle()) {
5707	ext4_debug("called recursively, non-PF_MEMALLOC!\n");
5708	dump_stack();
5709	return -EIO;
5710	}
5711
5712	/*
5713	* No need to force transaction in WB_SYNC_NONE mode. Also
5714	* ext4_sync_fs() will force the commit after everything is
5715	* written.
5716	*/
5717	if (wbc->sync_mode != WB_SYNC_ALL \|\| wbc->for_sync)
5718	return `0`;
5719
5720	err = ext4_fc_commit(journal: EXT4_SB(sb: inode->i_sb)->s_journal,
5721	EXT4_I(inode)->i_sync_tid);
5722	} else {
5723	struct ext4_iloc iloc;
5724
5725	err = __ext4_get_inode_loc_noinmem(inode, iloc: &iloc);
5726	if (err)
5727	return err;
5728	/*
5729	* sync(2) will flush the whole buffer cache. No need to do
5730	* it here separately for each inode.
5731	*/
5732	if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5733	sync_dirty_buffer(bh: iloc.bh);
5734	if (buffer_req(bh: iloc.bh) && !buffer_uptodate(bh: iloc.bh)) {
5735	ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5736	"IO error syncing inode");
5737	err = -EIO;
5738	}
5739	brelse(bh: iloc.bh);
5740	}
5741	return err;
5742	}
5743
5744	/*
5745	* In data=journal mode ext4_journalled_invalidate_folio() may fail to invalidate
5746	* buffers that are attached to a folio straddling i_size and are undergoing
5747	* commit. In that case we have to wait for commit to finish and try again.
5748	*/
5749	static void ext4_wait_for_tail_page_commit(struct inode *inode)
5750	{
5751	unsigned offset;
5752	journal_t *journal = EXT4_SB(sb: inode->i_sb)->s_journal;
5753	tid_t commit_tid;
5754	int ret;
5755	bool has_transaction;
5756
5757	offset = inode->i_size & (PAGE_SIZE - `1`);
5758	/*
5759	* If the folio is fully truncated, we don't need to wait for any commit
5760	* (and we even should not as __ext4_journalled_invalidate_folio() may
5761	* strip all buffers from the folio but keep the folio dirty which can then
5762	* confuse e.g. concurrent ext4_writepages() seeing dirty folio without
5763	* buffers). Also we don't need to wait for any commit if all buffers in
5764	* the folio remain valid. This is most beneficial for the common case of
5765	* blocksize == PAGESIZE.
5766	*/
5767	if (!offset \|\| offset > (PAGE_SIZE - i_blocksize(node: inode)))
5768	return;
5769	while (`1`) {
5770	struct folio *folio = filemap_lock_folio(mapping: inode->i_mapping,
5771	index: inode->i_size >> PAGE_SHIFT);
5772	if (IS_ERR(ptr: folio))
5773	return;
5774	ret = __ext4_journalled_invalidate_folio(folio, offset,
5775	length: folio_size(folio) - offset);
5776	folio_unlock(folio);
5777	folio_put(folio);
5778	if (ret != -EBUSY)
5779	return;
5780	has_transaction = false;
5781	read_lock(&journal->j_state_lock);
5782	if (journal->j_committing_transaction) {
5783	commit_tid = journal->j_committing_transaction->t_tid;
5784	has_transaction = true;
5785	}
5786	read_unlock(&journal->j_state_lock);
5787	if (has_transaction)
5788	jbd2_log_wait_commit(journal, tid: commit_tid);
5789	}
5790	}
5791
5792	/*
5793	* ext4_setattr()
5794	*
5795	* Called from notify_change.
5796	*
5797	* We want to trap VFS attempts to truncate the file as soon as
5798	* possible. In particular, we want to make sure that when the VFS
5799	* shrinks i_size, we put the inode on the orphan list and modify
5800	* i_disksize immediately, so that during the subsequent flushing of
5801	* dirty pages and freeing of disk blocks, we can guarantee that any
5802	* commit will leave the blocks being flushed in an unused state on
5803	* disk. (On recovery, the inode will get truncated and the blocks will
5804	* be freed, so we have a strong guarantee that no future commit will
5805	* leave these blocks visible to the user.)
5806	*
5807	* Another thing we have to assure is that if we are in ordered mode
5808	* and inode is still attached to the committing transaction, we must
5809	* we start writeout of all the dirty pages which are being truncated.
5810	* This way we are sure that all the data written in the previous
5811	* transaction are already on disk (truncate waits for pages under
5812	* writeback).
5813	*
5814	* Called with inode->i_rwsem down.
5815	*/
5816	int ext4_setattr(struct mnt_idmap idmap, struct* dentry *dentry,
5817	struct iattr *attr)
5818	{
5819	struct inode *inode = d_inode(dentry);
5820	int error, rc = `0`;
5821	int orphan = `0`;
5822	const unsigned int ia_valid = attr->ia_valid;
5823	bool inc_ivers = true;
5824
5825	error = ext4_emergency_state(sb: inode->i_sb);
5826	if (unlikely(error))
5827	return error;
5828
5829	if (unlikely(IS_IMMUTABLE(inode)))
5830	return -EPERM;
5831
5832	if (unlikely(IS_APPEND(inode) &&
5833	(ia_valid & (ATTR_MODE \| ATTR_UID \|
5834	ATTR_GID \| ATTR_TIMES_SET))))
5835	return -EPERM;
5836
5837	error = setattr_prepare(idmap, dentry, attr);
5838	if (error)
5839	return error;
5840
5841	error = fscrypt_prepare_setattr(dentry, attr);
5842	if (error)
5843	return error;
5844
5845	error = fsverity_prepare_setattr(dentry, attr);
5846	if (error)
5847	return error;
5848
5849	if (is_quota_modification(idmap, inode, ia: attr)) {
5850	error = dquot_initialize(inode);
5851	if (error)
5852	return error;
5853	}
5854
5855	if (i_uid_needs_update(idmap, attr, inode) \|\|
5856	i_gid_needs_update(idmap, attr, inode)) {
5857	handle_t *handle;
5858
5859	/ (user+group)(old+new) structure, inode write (sb,
5860	* inode block, ? - but truncate inode update has it) */
5861	handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5862	(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5863	EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + `3`);
5864	if (IS_ERR(ptr: handle)) {
5865	error = PTR_ERR(ptr: handle);
5866	goto err_out;
5867	}
5868
5869	/ dquot_transfer() calls back ext4_get_inode_usage() which*
5870	* counts xattr inode references.
5871	*/
5872	down_read(sem: &EXT4_I(inode)->xattr_sem);
5873	error = dquot_transfer(idmap, inode, iattr: attr);
5874	up_read(sem: &EXT4_I(inode)->xattr_sem);
5875
5876	if (error) {
5877	ext4_journal_stop(handle);
5878	return error;
5879	}
5880	/ Update corresponding info in inode so that everything is in*
5881	* one transaction */
5882	i_uid_update(idmap, attr, inode);
5883	i_gid_update(idmap, attr, inode);
5884	error = ext4_mark_inode_dirty(handle, inode);
5885	ext4_journal_stop(handle);
5886	if (unlikely(error)) {
5887	return error;
5888	}
5889	}
5890
5891	if (attr->ia_valid & ATTR_SIZE) {
5892	handle_t *handle;
5893	loff_t oldsize = inode->i_size;
5894	loff_t old_disksize;
5895	int shrink = (attr->ia_size < inode->i_size);
5896
5897	if (!(ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS))) {
5898	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
5899
5900	if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5901	return -EFBIG;
5902	}
5903	}
5904	if (!S_ISREG(inode->i_mode)) {
5905	return -EINVAL;
5906	}
5907
5908	if (attr->ia_size == inode->i_size)
5909	inc_ivers = false;
5910
5911	if (shrink) {
5912	if (ext4_should_order_data(inode)) {
5913	error = ext4_begin_ordered_truncate(inode,
5914	new_size: attr->ia_size);
5915	if (error)
5916	goto err_out;
5917	}
5918	/*
5919	* Blocks are going to be removed from the inode. Wait
5920	* for dio in flight.
5921	*/
5922	inode_dio_wait(inode);
5923	}
5924
5925	filemap_invalidate_lock(mapping: inode->i_mapping);
5926
5927	rc = ext4_break_layouts(inode);
5928	if (rc) {
5929	filemap_invalidate_unlock(mapping: inode->i_mapping);
5930	goto err_out;
5931	}
5932
5933	if (attr->ia_size != inode->i_size) {
5934	/ attach jbd2 jinode for EOF folio tail zeroing /
5935	if (attr->ia_size & (inode->i_sb->s_blocksize - `1`) \|\|
5936	oldsize & (inode->i_sb->s_blocksize - `1`)) {
5937	error = ext4_inode_attach_jinode(inode);
5938	if (error)
5939	goto out_mmap_sem;
5940	}
5941
5942	handle = ext4_journal_start(inode, EXT4_HT_INODE, `3`);
5943	if (IS_ERR(ptr: handle)) {
5944	error = PTR_ERR(ptr: handle);
5945	goto out_mmap_sem;
5946	}
5947	if (ext4_handle_valid(handle) && shrink) {
5948	error = ext4_orphan_add(handle, inode);
5949	orphan = `1`;
5950	}
5951	/*
5952	* Update c/mtime and tail zero the EOF folio on
5953	* truncate up. ext4_truncate() handles the shrink case
5954	* below.
5955	*/
5956	if (!shrink) {
5957	inode_set_mtime_to_ts(inode,
5958	ts: inode_set_ctime_current(inode));
5959	if (oldsize & (inode->i_sb->s_blocksize - `1`))
5960	ext4_block_truncate_page(handle,
5961	mapping: inode->i_mapping, from: oldsize);
5962	}
5963
5964	if (shrink)
5965	ext4_fc_track_range(handle, inode,
5966	start: (attr->ia_size > `0` ? attr->ia_size - `1` : `0`) >>
5967	inode->i_sb->s_blocksize_bits,
5968	EXT_MAX_BLOCKS - `1`);
5969	else
5970	ext4_fc_track_range(
5971	handle, inode,
5972	start: (oldsize > `0` ? oldsize - `1` : oldsize) >>
5973	inode->i_sb->s_blocksize_bits,
5974	end: (attr->ia_size > `0` ? attr->ia_size - `1` : `0`) >>
5975	inode->i_sb->s_blocksize_bits);
5976
5977	down_write(sem: &EXT4_I(inode)->i_data_sem);
5978	old_disksize = EXT4_I(inode)->i_disksize;
5979	EXT4_I(inode)->i_disksize = attr->ia_size;
5980
5981	/*
5982	* We have to update i_size under i_data_sem together
5983	* with i_disksize to avoid races with writeback code
5984	* running ext4_wb_update_i_disksize().
5985	*/
5986	if (!error)
5987	i_size_write(inode, i_size: attr->ia_size);
5988	else
5989	EXT4_I(inode)->i_disksize = old_disksize;
5990	up_write(sem: &EXT4_I(inode)->i_data_sem);
5991	rc = ext4_mark_inode_dirty(handle, inode);
5992	if (!error)
5993	error = rc;
5994	ext4_journal_stop(handle);
5995	if (error)
5996	goto out_mmap_sem;
5997	if (!shrink) {
5998	pagecache_isize_extended(inode, from: oldsize,
5999	to: inode->i_size);
6000	} else if (ext4_should_journal_data(inode)) {
6001	ext4_wait_for_tail_page_commit(inode);
6002	}
6003	}
6004
6005	/*
6006	* Truncate pagecache after we've waited for commit
6007	* in data=journal mode to make pages freeable.
6008	*/
6009	truncate_pagecache(inode, new: inode->i_size);
6010	/*
6011	* Call ext4_truncate() even if i_size didn't change to
6012	* truncate possible preallocated blocks.
6013	*/
6014	if (attr->ia_size <= oldsize) {
6015	rc = ext4_truncate(inode);
6016	if (rc)
6017	error = rc;
6018	}
6019	out_mmap_sem:
6020	filemap_invalidate_unlock(mapping: inode->i_mapping);
6021	}
6022
6023	if (!error) {
6024	if (inc_ivers)
6025	inode_inc_iversion(inode);
6026	setattr_copy(idmap, inode, attr);
6027	mark_inode_dirty(inode);
6028	}
6029
6030	/*
6031	* If the call to ext4_truncate failed to get a transaction handle at
6032	* all, we need to clean up the in-core orphan list manually.
6033	*/
6034	if (orphan && inode->i_nlink)
6035	ext4_orphan_del(NULL, inode);
6036
6037	if (!error && (ia_valid & ATTR_MODE))
6038	rc = posix_acl_chmod(idmap, dentry, inode->i_mode);
6039
6040	err_out:
6041	if (error)
6042	ext4_std_error(inode->i_sb, error);
6043	if (!error)
6044	error = rc;
6045	return error;
6046	}
6047
6048	u32 ext4_dio_alignment(struct inode *inode)
6049	{
6050	if (fsverity_active(inode))
6051	return `0`;
6052	if (ext4_should_journal_data(inode))
6053	return `0`;
6054	if (ext4_has_inline_data(inode))
6055	return `0`;
6056	if (IS_ENCRYPTED(inode)) {
6057	if (!fscrypt_dio_supported(inode))
6058	return `0`;
6059	return i_blocksize(node: inode);
6060	}
6061	return `1`; / use the iomap defaults /
6062	}
6063
6064	int ext4_getattr(struct mnt_idmap idmap, const* struct path *path,
6065	struct kstat stat, u32 request_mask, unsigned* int query_flags)
6066	{
6067	struct inode *inode = d_inode(dentry: path->dentry);
6068	struct ext4_inode *raw_inode;
6069	struct ext4_inode_info *ei = EXT4_I(inode);
6070	unsigned int flags;
6071
6072	if ((request_mask & STATX_BTIME) &&
6073	EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
6074	stat->result_mask \|= STATX_BTIME;
6075	stat->btime.tv_sec = ei->i_crtime.tv_sec;
6076	stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
6077	}
6078
6079	/*
6080	* Return the DIO alignment restrictions if requested. We only return
6081	* this information when requested, since on encrypted files it might
6082	* take a fair bit of work to get if the file wasn't opened recently.
6083	*/
6084	if ((request_mask & STATX_DIOALIGN) && S_ISREG(inode->i_mode)) {
6085	u32 dio_align = ext4_dio_alignment(inode);
6086
6087	stat->result_mask \|= STATX_DIOALIGN;
6088	if (dio_align == `1`) {
6089	struct block_device *bdev = inode->i_sb->s_bdev;
6090
6091	/ iomap defaults /
6092	stat->dio_mem_align = bdev_dma_alignment(bdev) + `1`;
6093	stat->dio_offset_align = bdev_logical_block_size(bdev);
6094	} else {
6095	stat->dio_mem_align = dio_align;
6096	stat->dio_offset_align = dio_align;
6097	}
6098	}
6099
6100	if ((request_mask & STATX_WRITE_ATOMIC) && S_ISREG(inode->i_mode)) {
6101	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
6102	unsigned int awu_min = `0`, awu_max = `0`;
6103
6104	if (ext4_inode_can_atomic_write(inode)) {
6105	awu_min = sbi->s_awu_min;
6106	awu_max = sbi->s_awu_max;
6107	}
6108
6109	generic_fill_statx_atomic_writes(stat, unit_min: awu_min, unit_max: awu_max, unit_max_opt: `0`);
6110	}
6111
6112	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
6113	if (flags & EXT4_APPEND_FL)
6114	stat->attributes \|= STATX_ATTR_APPEND;
6115	if (flags & EXT4_COMPR_FL)
6116	stat->attributes \|= STATX_ATTR_COMPRESSED;
6117	if (flags & EXT4_ENCRYPT_FL)
6118	stat->attributes \|= STATX_ATTR_ENCRYPTED;
6119	if (flags & EXT4_IMMUTABLE_FL)
6120	stat->attributes \|= STATX_ATTR_IMMUTABLE;
6121	if (flags & EXT4_NODUMP_FL)
6122	stat->attributes \|= STATX_ATTR_NODUMP;
6123	if (flags & EXT4_VERITY_FL)
6124	stat->attributes \|= STATX_ATTR_VERITY;
6125
6126	stat->attributes_mask \|= (STATX_ATTR_APPEND \|
6127	STATX_ATTR_COMPRESSED \|
6128	STATX_ATTR_ENCRYPTED \|
6129	STATX_ATTR_IMMUTABLE \|
6130	STATX_ATTR_NODUMP \|
6131	STATX_ATTR_VERITY);
6132
6133	generic_fillattr(idmap, request_mask, inode, stat);
6134	return `0`;
6135	}
6136
6137	int ext4_file_getattr(struct mnt_idmap *idmap,
6138	const struct path path, struct* kstat *stat,
6139	u32 request_mask, unsigned int query_flags)
6140	{
6141	struct inode *inode = d_inode(dentry: path->dentry);
6142	u64 delalloc_blocks;
6143
6144	ext4_getattr(idmap, path, stat, request_mask, query_flags);
6145
6146	/*
6147	* If there is inline data in the inode, the inode will normally not
6148	* have data blocks allocated (it may have an external xattr block).
6149	* Report at least one sector for such files, so tools like tar, rsync,
6150	* others don't incorrectly think the file is completely sparse.
6151	*/
6152	if (unlikely(ext4_has_inline_data(inode)))
6153	stat->blocks += (stat->size + `511`) >> `9`;
6154
6155	/*
6156	* We can't update i_blocks if the block allocation is delayed
6157	* otherwise in the case of system crash before the real block
6158	* allocation is done, we will have i_blocks inconsistent with
6159	* on-disk file blocks.
6160	* We always keep i_blocks updated together with real
6161	* allocation. But to not confuse with user, stat
6162	* will return the blocks that include the delayed allocation
6163	* blocks for this file.
6164	*/
6165	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
6166	EXT4_I(inode)->i_reserved_data_blocks);
6167	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - `9`);
6168	return `0`;
6169	}
6170
6171	static int ext4_index_trans_blocks(struct inode inode, int* lblocks,
6172	int pextents)
6173	{
6174	if (!(ext4_test_inode_flag(inode, bit: EXT4_INODE_EXTENTS)))
6175	return ext4_ind_trans_blocks(inode, nrblocks: lblocks);
6176	return ext4_ext_index_trans_blocks(inode, extents: pextents);
6177	}
6178
6179	/*
6180	* Account for index blocks, block groups bitmaps and block group
6181	* descriptor blocks if modify datablocks and index blocks
6182	* worse case, the indexs blocks spread over different block groups
6183	*
6184	* If datablocks are discontiguous, they are possible to spread over
6185	* different block groups too. If they are contiguous, with flexbg,
6186	* they could still across block group boundary.
6187	*
6188	* Also account for superblock, inode, quota and xattr blocks
6189	*/
6190	int ext4_meta_trans_blocks(struct inode inode, int* lblocks, int pextents)
6191	{
6192	ext4_group_t groups, ngroups = ext4_get_groups_count(sb: inode->i_sb);
6193	int gdpblocks;
6194	int idxblocks;
6195	int ret;
6196
6197	/*
6198	* How many index and leaf blocks need to touch to map @lblocks
6199	* logical blocks to @pextents physical extents?
6200	*/
6201	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
6202
6203	/*
6204	* Now let's see how many group bitmaps and group descriptors need
6205	* to account
6206	*/
6207	groups = idxblocks + pextents;
6208	gdpblocks = groups;
6209	if (groups > ngroups)
6210	groups = ngroups;
6211	if (groups > EXT4_SB(sb: inode->i_sb)->s_gdb_count)
6212	gdpblocks = EXT4_SB(sb: inode->i_sb)->s_gdb_count;
6213
6214	/ bitmaps and block group descriptor blocks /
6215	ret = idxblocks + groups + gdpblocks;
6216
6217	/ Blocks for super block, inode, quota and xattr blocks /
6218	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
6219
6220	return ret;
6221	}
6222
6223	/*
6224	* Calculate the journal credits for modifying the number of blocks
6225	* in a single extent within one transaction. 'nrblocks' is used only
6226	* for non-extent inodes. For extent type inodes, 'nrblocks' can be
6227	* zero if the exact number of blocks is unknown.
6228	*/
6229	int ext4_chunk_trans_extent(struct inode inode, int* nrblocks)
6230	{
6231	int ret;
6232
6233	ret = ext4_meta_trans_blocks(inode, lblocks: nrblocks, pextents: `1`);
6234	/ Account for data blocks for journalled mode /
6235	if (ext4_should_journal_data(inode))
6236	ret += nrblocks;
6237	return ret;
6238	}
6239
6240	/*
6241	* Calculate the journal credits for a chunk of data modification.
6242	*
6243	* This is called from DIO, fallocate or whoever calling
6244	* ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
6245	*
6246	* journal buffers for data blocks are not included here, as DIO
6247	* and fallocate do no need to journal data buffers.
6248	*/
6249	int ext4_chunk_trans_blocks(struct inode inode, int* nrblocks)
6250	{
6251	return ext4_meta_trans_blocks(inode, lblocks: nrblocks, pextents: `1`);
6252	}
6253
6254	/*
6255	* The caller must have previously called ext4_reserve_inode_write().
6256	* Give this, we know that the caller already has write access to iloc->bh.
6257	*/
6258	int ext4_mark_iloc_dirty(handle_t *handle,
6259	struct inode inode, struct* ext4_iloc *iloc)
6260	{
6261	int err = `0`;
6262
6263	err = ext4_emergency_state(sb: inode->i_sb);
6264	if (unlikely(err)) {
6265	put_bh(bh: iloc->bh);
6266	return err;
6267	}
6268	ext4_fc_track_inode(handle, inode);
6269
6270	/ the do_update_inode consumes one bh->b_count /
6271	get_bh(bh: iloc->bh);
6272
6273	/ ext4_do_update_inode() does jbd2_journal_dirty_metadata /
6274	err = ext4_do_update_inode(handle, inode, iloc);
6275	put_bh(bh: iloc->bh);
6276	return err;
6277	}
6278
6279	/*
6280	* On success, We end up with an outstanding reference count against
6281	* iloc->bh. This _must_ be cleaned up later.
6282	*/
6283
6284	int
6285	ext4_reserve_inode_write(handle_t handle, struct* inode *inode,
6286	struct ext4_iloc *iloc)
6287	{
6288	int err;
6289
6290	err = ext4_emergency_state(sb: inode->i_sb);
6291	if (unlikely(err))
6292	return err;
6293
6294	err = ext4_get_inode_loc(inode, iloc);
6295	if (!err) {
6296	BUFFER_TRACE(iloc->bh, "get_write_access");
6297	err = ext4_journal_get_write_access(handle, inode->i_sb,
6298	iloc->bh, EXT4_JTR_NONE);
6299	if (err) {
6300	brelse(bh: iloc->bh);
6301	iloc->bh = NULL;
6302	}
6303	ext4_fc_track_inode(handle, inode);
6304	}
6305	ext4_std_error(inode->i_sb, err);
6306	return err;
6307	}
6308
6309	static int __ext4_expand_extra_isize(struct inode *inode,
6310	unsigned int new_extra_isize,
6311	struct ext4_iloc *iloc,
6312	handle_t handle, int* *no_expand)
6313	{
6314	struct ext4_inode *raw_inode;
6315	struct ext4_xattr_ibody_header *header;
6316	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
6317	struct ext4_inode_info *ei = EXT4_I(inode);
6318	int error;
6319
6320	/ this was checked at iget time, but double check for good measure /
6321	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) \|\|
6322	(ei->i_extra_isize & `3`)) {
6323	EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
6324	ei->i_extra_isize,
6325	EXT4_INODE_SIZE(inode->i_sb));
6326	return -EFSCORRUPTED;
6327	}
6328	if ((new_extra_isize < ei->i_extra_isize) \|\|
6329	(new_extra_isize < `4`) \|\|
6330	(new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
6331	return -EINVAL; / Should never happen /
6332
6333	raw_inode = ext4_raw_inode(iloc);
6334
6335	header = IHDR(inode, raw_inode);
6336
6337	/ No extended attributes present /
6338	if (!ext4_test_inode_state(inode, bit: EXT4_STATE_XATTR) \|\|
6339	header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
6340	memset(s: (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
6341	EXT4_I(inode)->i_extra_isize, c: `0`,
6342	n: new_extra_isize - EXT4_I(inode)->i_extra_isize);
6343	EXT4_I(inode)->i_extra_isize = new_extra_isize;
6344	return `0`;
6345	}
6346
6347	/*
6348	* We may need to allocate external xattr block so we need quotas
6349	* initialized. Here we can be called with various locks held so we
6350	* cannot affort to initialize quotas ourselves. So just bail.
6351	*/
6352	if (dquot_initialize_needed(inode))
6353	return -EAGAIN;
6354
6355	/ try to expand with EAs present /
6356	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
6357	raw_inode, handle);
6358	if (error) {
6359	/*
6360	* Inode size expansion failed; don't try again
6361	*/
6362	*no_expand = `1`;
6363	}
6364
6365	return error;
6366	}
6367
6368	/*
6369	* Expand an inode by new_extra_isize bytes.
6370	* Returns 0 on success or negative error number on failure.
6371	*/
6372	static int ext4_try_to_expand_extra_isize(struct inode *inode,
6373	unsigned int new_extra_isize,
6374	struct ext4_iloc iloc,
6375	handle_t *handle)
6376	{
6377	int no_expand;
6378	int error;
6379
6380	if (ext4_test_inode_state(inode, bit: EXT4_STATE_NO_EXPAND))
6381	return -EOVERFLOW;
6382
6383	/*
6384	* In nojournal mode, we can immediately attempt to expand
6385	* the inode. When journaled, we first need to obtain extra
6386	* buffer credits since we may write into the EA block
6387	* with this same handle. If journal_extend fails, then it will
6388	* only result in a minor loss of functionality for that inode.
6389	* If this is felt to be critical, then e2fsck should be run to
6390	* force a large enough s_min_extra_isize.
6391	*/
6392	if (ext4_journal_extend(handle,
6393	EXT4_DATA_TRANS_BLOCKS(inode->i_sb), revoke: `0`) != `0`)
6394	return -ENOSPC;
6395
6396	if (ext4_write_trylock_xattr(inode, save: &no_expand) == `0`)
6397	return -EBUSY;
6398
6399	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc: &iloc,
6400	handle, no_expand: &no_expand);
6401	ext4_write_unlock_xattr(inode, save: &no_expand);
6402
6403	return error;
6404	}
6405
6406	int ext4_expand_extra_isize(struct inode *inode,
6407	unsigned int new_extra_isize,
6408	struct ext4_iloc *iloc)
6409	{
6410	handle_t *handle;
6411	int no_expand;
6412	int error, rc;
6413
6414	if (ext4_test_inode_state(inode, bit: EXT4_STATE_NO_EXPAND)) {
6415	brelse(bh: iloc->bh);
6416	return -EOVERFLOW;
6417	}
6418
6419	handle = ext4_journal_start(inode, EXT4_HT_INODE,
6420	EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
6421	if (IS_ERR(ptr: handle)) {
6422	error = PTR_ERR(ptr: handle);
6423	brelse(bh: iloc->bh);
6424	return error;
6425	}
6426
6427	ext4_write_lock_xattr(inode, save: &no_expand);
6428
6429	BUFFER_TRACE(iloc->bh, "get_write_access");
6430	error = ext4_journal_get_write_access(handle, inode->i_sb, iloc->bh,
6431	EXT4_JTR_NONE);
6432	if (error) {
6433	brelse(bh: iloc->bh);
6434	goto out_unlock;
6435	}
6436
6437	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
6438	handle, no_expand: &no_expand);
6439
6440	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
6441	if (!error)
6442	error = rc;
6443
6444	out_unlock:
6445	ext4_write_unlock_xattr(inode, save: &no_expand);
6446	ext4_journal_stop(handle);
6447	return error;
6448	}
6449
6450	/*
6451	* What we do here is to mark the in-core inode as clean with respect to inode
6452	* dirtiness (it may still be data-dirty).
6453	* This means that the in-core inode may be reaped by prune_icache
6454	* without having to perform any I/O. This is a very good thing,
6455	* because any task may call prune_icache - even ones which
6456	* have a transaction open against a different journal.
6457	*
6458	* Is this cheating? Not really. Sure, we haven't written the
6459	* inode out, but prune_icache isn't a user-visible syncing function.
6460	* Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
6461	* we start and wait on commits.
6462	*/
6463	int __ext4_mark_inode_dirty(handle_t handle, struct* inode *inode,
6464	const char func, unsigned* int line)
6465	{
6466	struct ext4_iloc iloc;
6467	struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
6468	int err;
6469
6470	might_sleep();
6471	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
6472	err = ext4_reserve_inode_write(handle, inode, iloc: &iloc);
6473	if (err)
6474	goto out;
6475
6476	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
6477	ext4_try_to_expand_extra_isize(inode, new_extra_isize: sbi->s_want_extra_isize,
6478	iloc, handle);
6479
6480	err = ext4_mark_iloc_dirty(handle, inode, iloc: &iloc);
6481	out:
6482	if (unlikely(err))
6483	ext4_error_inode_err(inode, func, line, `0`, err,
6484	"mark_inode_dirty error");
6485	return err;
6486	}
6487
6488	/*
6489	* ext4_dirty_inode() is called from __mark_inode_dirty()
6490	*
6491	* We're really interested in the case where a file is being extended.
6492	* i_size has been changed by generic_commit_write() and we thus need
6493	* to include the updated inode in the current transaction.
6494	*
6495	* Also, dquot_alloc_block() will always dirty the inode when blocks
6496	* are allocated to the file.
6497	*
6498	* If the inode is marked synchronous, we don't honour that here - doing
6499	* so would cause a commit on atime updates, which we don't bother doing.
6500	* We handle synchronous inodes at the highest possible level.
6501	*/
6502	void ext4_dirty_inode(struct inode inode, int* flags)
6503	{
6504	handle_t *handle;
6505
6506	handle = ext4_journal_start(inode, EXT4_HT_INODE, `2`);
6507	if (IS_ERR(ptr: handle))
6508	return;
6509	ext4_mark_inode_dirty(handle, inode);
6510	ext4_journal_stop(handle);
6511	}
6512
6513	int ext4_change_inode_journal_flag(struct inode inode, int* val)
6514	{
6515	journal_t *journal;
6516	handle_t *handle;
6517	int err;
6518	int alloc_ctx;
6519
6520	/*
6521	* We have to be very careful here: changing a data block's
6522	* journaling status dynamically is dangerous. If we write a
6523	* data block to the journal, change the status and then delete
6524	* that block, we risk forgetting to revoke the old log record
6525	* from the journal and so a subsequent replay can corrupt data.
6526	* So, first we make sure that the journal is empty and that
6527	* nobody is changing anything.
6528	*/
6529
6530	journal = EXT4_JOURNAL(inode);
6531	if (!journal)
6532	return `0`;
6533	if (is_journal_aborted(journal))
6534	return -EROFS;
6535
6536	/ Wait for all existing dio workers /
6537	inode_dio_wait(inode);
6538
6539	/*
6540	* Before flushing the journal and switching inode's aops, we have
6541	* to flush all dirty data the inode has. There can be outstanding
6542	* delayed allocations, there can be unwritten extents created by
6543	* fallocate or buffered writes in dioread_nolock mode covered by
6544	* dirty data which can be converted only after flushing the dirty
6545	* data (and journalled aops don't know how to handle these cases).
6546	*/
6547	if (val) {
6548	filemap_invalidate_lock(mapping: inode->i_mapping);
6549	err = filemap_write_and_wait(mapping: inode->i_mapping);
6550	if (err < `0`) {
6551	filemap_invalidate_unlock(mapping: inode->i_mapping);
6552	return err;
6553	}
6554	}
6555
6556	alloc_ctx = ext4_writepages_down_write(sb: inode->i_sb);
6557	jbd2_journal_lock_updates(journal);
6558
6559	/*
6560	* OK, there are no updates running now, and all cached data is
6561	* synced to disk. We are now in a completely consistent state
6562	* which doesn't have anything in the journal, and we know that
6563	* no filesystem updates are running, so it is safe to modify
6564	* the inode's in-core data-journaling state flag now.
6565	*/
6566
6567	if (val)
6568	ext4_set_inode_flag(inode, bit: EXT4_INODE_JOURNAL_DATA);
6569	else {
6570	err = jbd2_journal_flush(journal, flags: `0`);
6571	if (err < `0`) {
6572	jbd2_journal_unlock_updates(journal);
6573	ext4_writepages_up_write(sb: inode->i_sb, ctx: alloc_ctx);
6574	return err;
6575	}
6576	ext4_clear_inode_flag(inode, bit: EXT4_INODE_JOURNAL_DATA);
6577	}
6578	ext4_set_aops(inode);
6579
6580	jbd2_journal_unlock_updates(journal);
6581	ext4_writepages_up_write(sb: inode->i_sb, ctx: alloc_ctx);
6582
6583	if (val)
6584	filemap_invalidate_unlock(mapping: inode->i_mapping);
6585
6586	/ Finally we can mark the inode as dirty. /
6587
6588	handle = ext4_journal_start(inode, EXT4_HT_INODE, `1`);
6589	if (IS_ERR(ptr: handle))
6590	return PTR_ERR(ptr: handle);
6591
6592	ext4_fc_mark_ineligible(sb: inode->i_sb,
6593	reason: EXT4_FC_REASON_JOURNAL_FLAG_CHANGE, handle);
6594	err = ext4_mark_inode_dirty(handle, inode);
6595	ext4_handle_sync(handle);
6596	ext4_journal_stop(handle);
6597	ext4_std_error(inode->i_sb, err);
6598
6599	return err;
6600	}
6601
6602	static int ext4_bh_unmapped(handle_t handle, struct* inode *inode,
6603	struct buffer_head *bh)
6604	{
6605	return !buffer_mapped(bh);
6606	}
6607
6608	static int ext4_block_page_mkwrite(struct inode inode, struct* folio *folio,
6609	get_block_t get_block)
6610	{
6611	handle_t *handle;
6612	loff_t size;
6613	unsigned long len;
6614	int credits;
6615	int ret;
6616
6617	credits = ext4_chunk_trans_extent(inode,
6618	nrblocks: ext4_journal_blocks_per_folio(inode));
6619	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, credits);
6620	if (IS_ERR(ptr: handle))
6621	return PTR_ERR(ptr: handle);
6622
6623	folio_lock(folio);
6624	size = i_size_read(inode);
6625	/ Page got truncated from under us? /
6626	if (folio->mapping != inode->i_mapping \|\| folio_pos(folio) > size) {
6627	ret = -EFAULT;
6628	goto out_error;
6629	}
6630
6631	len = folio_size(folio);
6632	if (folio_pos(folio) + len > size)
6633	len = size - folio_pos(folio);
6634
6635	ret = ext4_block_write_begin(handle, folio, pos: `0`, len, get_block);
6636	if (ret)
6637	goto out_error;
6638
6639	if (!ext4_should_journal_data(inode)) {
6640	block_commit_write(folio, from: `0`, to: len);
6641	folio_mark_dirty(folio);
6642	} else {
6643	ret = ext4_journal_folio_buffers(handle, folio, len);
6644	if (ret)
6645	goto out_error;
6646	}
6647	ext4_journal_stop(handle);
6648	folio_wait_stable(folio);
6649	return ret;
6650
6651	out_error:
6652	folio_unlock(folio);
6653	ext4_journal_stop(handle);
6654	return ret;
6655	}
6656
6657	vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6658	{
6659	struct vm_area_struct *vma = vmf->vma;
6660	struct folio *folio = page_folio(vmf->page);
6661	loff_t size;
6662	unsigned long len;
6663	int err;
6664	vm_fault_t ret;
6665	struct file *file = vma->vm_file;
6666	struct inode *inode = file_inode(f: file);
6667	struct address_space *mapping = inode->i_mapping;
6668	get_block_t *get_block = ext4_get_block;
6669	int retries = `0`;
6670
6671	if (unlikely(IS_IMMUTABLE(inode)))
6672	return VM_FAULT_SIGBUS;
6673
6674	sb_start_pagefault(sb: inode->i_sb);
6675	file_update_time(file: vma->vm_file);
6676
6677	filemap_invalidate_lock_shared(mapping);
6678
6679	err = ext4_convert_inline_data(inode);
6680	if (err)
6681	goto out_ret;
6682
6683	/*
6684	* On data journalling we skip straight to the transaction handle:
6685	* there's no delalloc; page truncated will be checked later; the
6686	* early return w/ all buffers mapped (calculates size/len) can't
6687	* be used; and there's no dioread_nolock, so only ext4_get_block.
6688	*/
6689	if (ext4_should_journal_data(inode))
6690	goto retry_alloc;
6691
6692	/ Delalloc case is easy... /
6693	if (test_opt(inode->i_sb, DELALLOC) &&
6694	!ext4_nonda_switch(sb: inode->i_sb)) {
6695	do {
6696	err = block_page_mkwrite(vma, vmf,
6697	get_block: ext4_da_get_block_prep);
6698	} while (err == -ENOSPC &&
6699	ext4_should_retry_alloc(sb: inode->i_sb, retries: &retries));
6700	goto out_ret;
6701	}
6702
6703	folio_lock(folio);
6704	size = i_size_read(inode);
6705	/ Page got truncated from under us? /
6706	if (folio->mapping != mapping \|\| folio_pos(folio) > size) {
6707	folio_unlock(folio);
6708	ret = VM_FAULT_NOPAGE;
6709	goto out;
6710	}
6711
6712	len = folio_size(folio);
6713	if (folio_pos(folio) + len > size)
6714	len = size - folio_pos(folio);
6715	/*
6716	* Return if we have all the buffers mapped. This avoids the need to do
6717	* journal_start/journal_stop which can block and take a long time
6718	*
6719	* This cannot be done for data journalling, as we have to add the
6720	* inode to the transaction's list to writeprotect pages on commit.
6721	*/
6722	if (folio_buffers(folio)) {
6723	if (!ext4_walk_page_buffers(NULL, inode, folio_buffers(folio),
6724	from: `0`, to: len, NULL,
6725	fn: ext4_bh_unmapped)) {
6726	/ Wait so that we don't change page under IO /
6727	folio_wait_stable(folio);
6728	ret = VM_FAULT_LOCKED;
6729	goto out;
6730	}
6731	}
6732	folio_unlock(folio);
6733	/ OK, we need to fill the hole... /
6734	if (ext4_should_dioread_nolock(inode))
6735	get_block = ext4_get_block_unwritten;
6736	retry_alloc:
6737	/ Start journal and allocate blocks /
6738	err = ext4_block_page_mkwrite(inode, folio, get_block);
6739	if (err == -EAGAIN \|\|
6740	(err == -ENOSPC && ext4_should_retry_alloc(sb: inode->i_sb, retries: &retries)))
6741	goto retry_alloc;
6742	out_ret:
6743	ret = vmf_fs_error(err);
6744	out:
6745	filemap_invalidate_unlock_shared(mapping);
6746	sb_end_pagefault(sb: inode->i_sb);
6747	return ret;
6748	}
6749

Browse the source code of Linux/fs/ext4/inode.c