xref: /openbmc/linux/fs/ext4/inode.c (revision 2f190ac2)
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/namei.h>
35 #include <linux/uio.h>
36 #include <linux/bio.h>
37 #include <linux/workqueue.h>
38 #include <linux/kernel.h>
39 #include <linux/printk.h>
40 #include <linux/slab.h>
41 #include <linux/bitops.h>
42 #include <linux/iomap.h>
43 #include <linux/iversion.h>
44 
45 #include "ext4_jbd2.h"
46 #include "xattr.h"
47 #include "acl.h"
48 #include "truncate.h"
49 
50 #include <trace/events/ext4.h>
51 
52 static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
53 			      struct ext4_inode_info *ei)
54 {
55 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
56 	__u32 csum;
57 	__u16 dummy_csum = 0;
58 	int offset = offsetof(struct ext4_inode, i_checksum_lo);
59 	unsigned int csum_size = sizeof(dummy_csum);
60 
61 	csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
62 	csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
63 	offset += csum_size;
64 	csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
65 			   EXT4_GOOD_OLD_INODE_SIZE - offset);
66 
67 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
68 		offset = offsetof(struct ext4_inode, i_checksum_hi);
69 		csum = ext4_chksum(sbi, csum, (__u8 *)raw +
70 				   EXT4_GOOD_OLD_INODE_SIZE,
71 				   offset - EXT4_GOOD_OLD_INODE_SIZE);
72 		if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
73 			csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
74 					   csum_size);
75 			offset += csum_size;
76 		}
77 		csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
78 				   EXT4_INODE_SIZE(inode->i_sb) - offset);
79 	}
80 
81 	return csum;
82 }
83 
84 static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
85 				  struct ext4_inode_info *ei)
86 {
87 	__u32 provided, calculated;
88 
89 	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
90 	    cpu_to_le32(EXT4_OS_LINUX) ||
91 	    !ext4_has_metadata_csum(inode->i_sb))
92 		return 1;
93 
94 	provided = le16_to_cpu(raw->i_checksum_lo);
95 	calculated = ext4_inode_csum(inode, raw, ei);
96 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
97 	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
98 		provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
99 	else
100 		calculated &= 0xFFFF;
101 
102 	return provided == calculated;
103 }
104 
105 void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
106 			 struct ext4_inode_info *ei)
107 {
108 	__u32 csum;
109 
110 	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
111 	    cpu_to_le32(EXT4_OS_LINUX) ||
112 	    !ext4_has_metadata_csum(inode->i_sb))
113 		return;
114 
115 	csum = ext4_inode_csum(inode, raw, ei);
116 	raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
117 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
118 	    EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
119 		raw->i_checksum_hi = cpu_to_le16(csum >> 16);
120 }
121 
122 static inline int ext4_begin_ordered_truncate(struct inode *inode,
123 					      loff_t new_size)
124 {
125 	trace_ext4_begin_ordered_truncate(inode, new_size);
126 	/*
127 	 * If jinode is zero, then we never opened the file for
128 	 * writing, so there's no need to call
129 	 * jbd2_journal_begin_ordered_truncate() since there's no
130 	 * outstanding writes we need to flush.
131 	 */
132 	if (!EXT4_I(inode)->jinode)
133 		return 0;
134 	return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
135 						   EXT4_I(inode)->jinode,
136 						   new_size);
137 }
138 
139 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
140 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
141 				  int pextents);
142 
143 /*
144  * Test whether an inode is a fast symlink.
145  * 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_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
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 	if (EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)
181 		ext4_evict_ea_inode(inode);
182 	if (inode->i_nlink) {
183 		/*
184 		 * When journalling data dirty buffers are tracked only in the
185 		 * journal. So although mm thinks everything is clean and
186 		 * ready for reaping the inode might still have some pages to
187 		 * write in the running transaction or waiting to be
188 		 * checkpointed. Thus calling jbd2_journal_invalidate_folio()
189 		 * (via truncate_inode_pages()) to discard these buffers can
190 		 * cause data loss. Also even if we did not discard these
191 		 * buffers, we would have no way to find them after the inode
192 		 * is reaped and thus user could see stale data if he tries to
193 		 * read them before the transaction is checkpointed. So be
194 		 * careful and force everything to disk here... We use
195 		 * ei->i_datasync_tid to store the newest transaction
196 		 * containing inode's data.
197 		 *
198 		 * Note that directories do not have this problem because they
199 		 * don't use page cache.
200 		 */
201 		if (inode->i_ino != EXT4_JOURNAL_INO &&
202 		    ext4_should_journal_data(inode) &&
203 		    S_ISREG(inode->i_mode) && inode->i_data.nrpages) {
204 			journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
205 			tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
206 
207 			jbd2_complete_transaction(journal, commit_tid);
208 			filemap_write_and_wait(&inode->i_data);
209 		}
210 		truncate_inode_pages_final(&inode->i_data);
211 
212 		goto no_delete;
213 	}
214 
215 	if (is_bad_inode(inode))
216 		goto no_delete;
217 	dquot_initialize(inode);
218 
219 	if (ext4_should_order_data(inode))
220 		ext4_begin_ordered_truncate(inode, 0);
221 	truncate_inode_pages_final(&inode->i_data);
222 
223 	/*
224 	 * For inodes with journalled data, transaction commit could have
225 	 * dirtied the inode. Flush worker is ignoring it because of I_FREEING
226 	 * flag but we still need to remove the inode from the writeback lists.
227 	 */
228 	if (!list_empty_careful(&inode->i_io_list)) {
229 		WARN_ON_ONCE(!ext4_should_journal_data(inode));
230 		inode_io_list_del(inode);
231 	}
232 
233 	/*
234 	 * Protect us against freezing - iput() caller didn't have to have any
235 	 * protection against it. When we are in a running transaction though,
236 	 * we are already protected against freezing and we cannot grab further
237 	 * protection due to lock ordering constraints.
238 	 */
239 	if (!ext4_journal_current_handle()) {
240 		sb_start_intwrite(inode->i_sb);
241 		freeze_protected = true;
242 	}
243 
244 	if (!IS_NOQUOTA(inode))
245 		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
246 
247 	/*
248 	 * Block bitmap, group descriptor, and inode are accounted in both
249 	 * ext4_blocks_for_truncate() and extra_credits. So subtract 3.
250 	 */
251 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
252 			 ext4_blocks_for_truncate(inode) + extra_credits - 3);
253 	if (IS_ERR(handle)) {
254 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
255 		/*
256 		 * If we're going to skip the normal cleanup, we still need to
257 		 * make sure that the in-core orphan linked list is properly
258 		 * cleaned up.
259 		 */
260 		ext4_orphan_del(NULL, inode);
261 		if (freeze_protected)
262 			sb_end_intwrite(inode->i_sb);
263 		goto no_delete;
264 	}
265 
266 	if (IS_SYNC(inode))
267 		ext4_handle_sync(handle);
268 
269 	/*
270 	 * Set inode->i_size to 0 before calling ext4_truncate(). We need
271 	 * special handling of symlinks here because i_size is used to
272 	 * determine whether ext4_inode_info->i_data contains symlink data or
273 	 * block mappings. Setting i_size to 0 will remove its fast symlink
274 	 * status. Erase i_data so that it becomes a valid empty block map.
275 	 */
276 	if (ext4_inode_is_fast_symlink(inode))
277 		memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
278 	inode->i_size = 0;
279 	err = ext4_mark_inode_dirty(handle, inode);
280 	if (err) {
281 		ext4_warning(inode->i_sb,
282 			     "couldn't mark inode dirty (err %d)", err);
283 		goto stop_handle;
284 	}
285 	if (inode->i_blocks) {
286 		err = ext4_truncate(inode);
287 		if (err) {
288 			ext4_error_err(inode->i_sb, -err,
289 				       "couldn't truncate inode %lu (err %d)",
290 				       inode->i_ino, err);
291 			goto stop_handle;
292 		}
293 	}
294 
295 	/* Remove xattr references. */
296 	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
297 				      extra_credits);
298 	if (err) {
299 		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
300 stop_handle:
301 		ext4_journal_stop(handle);
302 		ext4_orphan_del(NULL, inode);
303 		if (freeze_protected)
304 			sb_end_intwrite(inode->i_sb);
305 		ext4_xattr_inode_array_free(ea_inode_array);
306 		goto no_delete;
307 	}
308 
309 	/*
310 	 * Kill off the orphan record which ext4_truncate created.
311 	 * AKPM: I think this can be inside the above `if'.
312 	 * Note that ext4_orphan_del() has to be able to cope with the
313 	 * deletion of a non-existent orphan - this is because we don't
314 	 * know if ext4_truncate() actually created an orphan record.
315 	 * (Well, we could do this if we need to, but heck - it works)
316 	 */
317 	ext4_orphan_del(handle, inode);
318 	EXT4_I(inode)->i_dtime	= (__u32)ktime_get_real_seconds();
319 
320 	/*
321 	 * One subtle ordering requirement: if anything has gone wrong
322 	 * (transaction abort, IO errors, whatever), then we can still
323 	 * do these next steps (the fs will already have been marked as
324 	 * having errors), but we can't free the inode if the mark_dirty
325 	 * fails.
326 	 */
327 	if (ext4_mark_inode_dirty(handle, inode))
328 		/* If that failed, just do the required in-core inode clear. */
329 		ext4_clear_inode(inode);
330 	else
331 		ext4_free_inode(handle, inode);
332 	ext4_journal_stop(handle);
333 	if (freeze_protected)
334 		sb_end_intwrite(inode->i_sb);
335 	ext4_xattr_inode_array_free(ea_inode_array);
336 	return;
337 no_delete:
338 	if (!list_empty(&EXT4_I(inode)->i_fc_list))
339 		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL);
340 	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
341 }
342 
343 #ifdef CONFIG_QUOTA
344 qsize_t *ext4_get_reserved_space(struct inode *inode)
345 {
346 	return &EXT4_I(inode)->i_reserved_quota;
347 }
348 #endif
349 
350 /*
351  * Called with i_data_sem down, which is important since we can call
352  * ext4_discard_preallocations() from here.
353  */
354 void ext4_da_update_reserve_space(struct inode *inode,
355 					int used, int quota_claim)
356 {
357 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
358 	struct ext4_inode_info *ei = EXT4_I(inode);
359 
360 	spin_lock(&ei->i_block_reservation_lock);
361 	trace_ext4_da_update_reserve_space(inode, used, quota_claim);
362 	if (unlikely(used > ei->i_reserved_data_blocks)) {
363 		ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
364 			 "with only %d reserved data blocks",
365 			 __func__, inode->i_ino, used,
366 			 ei->i_reserved_data_blocks);
367 		WARN_ON(1);
368 		used = ei->i_reserved_data_blocks;
369 	}
370 
371 	/* Update per-inode reservations */
372 	ei->i_reserved_data_blocks -= used;
373 	percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
374 
375 	spin_unlock(&ei->i_block_reservation_lock);
376 
377 	/* Update quota subsystem for data blocks */
378 	if (quota_claim)
379 		dquot_claim_block(inode, EXT4_C2B(sbi, used));
380 	else {
381 		/*
382 		 * We did fallocate with an offset that is already delayed
383 		 * allocated. So on delayed allocated writeback we should
384 		 * not re-claim the quota for fallocated blocks.
385 		 */
386 		dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
387 	}
388 
389 	/*
390 	 * If we have done all the pending block allocations and if
391 	 * there aren't any writers on the inode, we can discard the
392 	 * inode's preallocations.
393 	 */
394 	if ((ei->i_reserved_data_blocks == 0) &&
395 	    !inode_is_open_for_write(inode))
396 		ext4_discard_preallocations(inode, 0);
397 }
398 
399 static int __check_block_validity(struct inode *inode, const char *func,
400 				unsigned int line,
401 				struct ext4_map_blocks *map)
402 {
403 	if (ext4_has_feature_journal(inode->i_sb) &&
404 	    (inode->i_ino ==
405 	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
406 		return 0;
407 	if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
408 		ext4_error_inode(inode, func, line, map->m_pblk,
409 				 "lblock %lu mapped to illegal pblock %llu "
410 				 "(length %d)", (unsigned long) map->m_lblk,
411 				 map->m_pblk, map->m_len);
412 		return -EFSCORRUPTED;
413 	}
414 	return 0;
415 }
416 
417 int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
418 		       ext4_lblk_t len)
419 {
420 	int ret;
421 
422 	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
423 		return fscrypt_zeroout_range(inode, lblk, pblk, len);
424 
425 	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
426 	if (ret > 0)
427 		ret = 0;
428 
429 	return ret;
430 }
431 
432 #define check_block_validity(inode, map)	\
433 	__check_block_validity((inode), __func__, __LINE__, (map))
434 
435 #ifdef ES_AGGRESSIVE_TEST
436 static void ext4_map_blocks_es_recheck(handle_t *handle,
437 				       struct inode *inode,
438 				       struct ext4_map_blocks *es_map,
439 				       struct ext4_map_blocks *map,
440 				       int flags)
441 {
442 	int retval;
443 
444 	map->m_flags = 0;
445 	/*
446 	 * There is a race window that the result is not the same.
447 	 * e.g. xfstests #223 when dioread_nolock enables.  The reason
448 	 * is that we lookup a block mapping in extent status tree with
449 	 * out taking i_data_sem.  So at the time the unwritten extent
450 	 * could be converted.
451 	 */
452 	down_read(&EXT4_I(inode)->i_data_sem);
453 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
454 		retval = ext4_ext_map_blocks(handle, inode, map, 0);
455 	} else {
456 		retval = ext4_ind_map_blocks(handle, inode, map, 0);
457 	}
458 	up_read((&EXT4_I(inode)->i_data_sem));
459 
460 	/*
461 	 * We don't check m_len because extent will be collpased in status
462 	 * tree.  So the m_len might not equal.
463 	 */
464 	if (es_map->m_lblk != map->m_lblk ||
465 	    es_map->m_flags != map->m_flags ||
466 	    es_map->m_pblk != map->m_pblk) {
467 		printk("ES cache assertion failed for inode: %lu "
468 		       "es_cached ex [%d/%d/%llu/%x] != "
469 		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
470 		       inode->i_ino, es_map->m_lblk, es_map->m_len,
471 		       es_map->m_pblk, es_map->m_flags, map->m_lblk,
472 		       map->m_len, map->m_pblk, map->m_flags,
473 		       retval, flags);
474 	}
475 }
476 #endif /* ES_AGGRESSIVE_TEST */
477 
478 /*
479  * The ext4_map_blocks() function tries to look up the requested blocks,
480  * and returns if the blocks are already mapped.
481  *
482  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
483  * and store the allocated blocks in the result buffer head and mark it
484  * mapped.
485  *
486  * If file type is extents based, it will call ext4_ext_map_blocks(),
487  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
488  * based files
489  *
490  * On success, it returns the number of blocks being mapped or allocated.  if
491  * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
492  * is marked as unwritten. If the create == 1, it will mark @map as mapped.
493  *
494  * It returns 0 if plain look up failed (blocks have not been allocated), in
495  * that case, @map is returned as unmapped but we still do fill map->m_len to
496  * indicate the length of a hole starting at map->m_lblk.
497  *
498  * It returns the error in case of allocation failure.
499  */
500 int ext4_map_blocks(handle_t *handle, struct inode *inode,
501 		    struct ext4_map_blocks *map, int flags)
502 {
503 	struct extent_status es;
504 	int retval;
505 	int ret = 0;
506 #ifdef ES_AGGRESSIVE_TEST
507 	struct ext4_map_blocks orig_map;
508 
509 	memcpy(&orig_map, map, sizeof(*map));
510 #endif
511 
512 	map->m_flags = 0;
513 	ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
514 		  flags, map->m_len, (unsigned long) map->m_lblk);
515 
516 	/*
517 	 * ext4_map_blocks returns an int, and m_len is an unsigned int
518 	 */
519 	if (unlikely(map->m_len > INT_MAX))
520 		map->m_len = INT_MAX;
521 
522 	/* We can handle the block number less than EXT_MAX_BLOCKS */
523 	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
524 		return -EFSCORRUPTED;
525 
526 	/* Lookup extent status tree firstly */
527 	if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
528 	    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
529 		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
530 			map->m_pblk = ext4_es_pblock(&es) +
531 					map->m_lblk - es.es_lblk;
532 			map->m_flags |= ext4_es_is_written(&es) ?
533 					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
534 			retval = es.es_len - (map->m_lblk - es.es_lblk);
535 			if (retval > map->m_len)
536 				retval = map->m_len;
537 			map->m_len = retval;
538 		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
539 			map->m_pblk = 0;
540 			retval = es.es_len - (map->m_lblk - es.es_lblk);
541 			if (retval > map->m_len)
542 				retval = map->m_len;
543 			map->m_len = retval;
544 			retval = 0;
545 		} else {
546 			BUG();
547 		}
548 
549 		if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
550 			return retval;
551 #ifdef ES_AGGRESSIVE_TEST
552 		ext4_map_blocks_es_recheck(handle, inode, map,
553 					   &orig_map, flags);
554 #endif
555 		goto found;
556 	}
557 	/*
558 	 * In the query cache no-wait mode, nothing we can do more if we
559 	 * cannot find extent in the cache.
560 	 */
561 	if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
562 		return 0;
563 
564 	/*
565 	 * Try to see if we can get the block without requesting a new
566 	 * file system block.
567 	 */
568 	down_read(&EXT4_I(inode)->i_data_sem);
569 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
570 		retval = ext4_ext_map_blocks(handle, inode, map, 0);
571 	} else {
572 		retval = ext4_ind_map_blocks(handle, inode, map, 0);
573 	}
574 	if (retval > 0) {
575 		unsigned int status;
576 
577 		if (unlikely(retval != map->m_len)) {
578 			ext4_warning(inode->i_sb,
579 				     "ES len assertion failed for inode "
580 				     "%lu: retval %d != map->m_len %d",
581 				     inode->i_ino, retval, map->m_len);
582 			WARN_ON(1);
583 		}
584 
585 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
586 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
587 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
588 		    !(status & EXTENT_STATUS_WRITTEN) &&
589 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
590 				       map->m_lblk + map->m_len - 1))
591 			status |= EXTENT_STATUS_DELAYED;
592 		ret = ext4_es_insert_extent(inode, map->m_lblk,
593 					    map->m_len, map->m_pblk, status);
594 		if (ret < 0)
595 			retval = ret;
596 	}
597 	up_read((&EXT4_I(inode)->i_data_sem));
598 
599 found:
600 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
601 		ret = check_block_validity(inode, map);
602 		if (ret != 0)
603 			return ret;
604 	}
605 
606 	/* If it is only a block(s) look up */
607 	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
608 		return retval;
609 
610 	/*
611 	 * Returns if the blocks have already allocated
612 	 *
613 	 * Note that if blocks have been preallocated
614 	 * ext4_ext_get_block() returns the create = 0
615 	 * with buffer head unmapped.
616 	 */
617 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
618 		/*
619 		 * If we need to convert extent to unwritten
620 		 * we continue and do the actual work in
621 		 * ext4_ext_map_blocks()
622 		 */
623 		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
624 			return retval;
625 
626 	/*
627 	 * Here we clear m_flags because after allocating an new extent,
628 	 * it will be set again.
629 	 */
630 	map->m_flags &= ~EXT4_MAP_FLAGS;
631 
632 	/*
633 	 * New blocks allocate and/or writing to unwritten extent
634 	 * will possibly result in updating i_data, so we take
635 	 * the write lock of i_data_sem, and call get_block()
636 	 * with create == 1 flag.
637 	 */
638 	down_write(&EXT4_I(inode)->i_data_sem);
639 
640 	/*
641 	 * We need to check for EXT4 here because migrate
642 	 * could have changed the inode type in between
643 	 */
644 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
645 		retval = ext4_ext_map_blocks(handle, inode, map, flags);
646 	} else {
647 		retval = ext4_ind_map_blocks(handle, inode, map, flags);
648 
649 		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
650 			/*
651 			 * We allocated new blocks which will result in
652 			 * i_data's format changing.  Force the migrate
653 			 * to fail by clearing migrate flags
654 			 */
655 			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
656 		}
657 
658 		/*
659 		 * Update reserved blocks/metadata blocks after successful
660 		 * block allocation which had been deferred till now. We don't
661 		 * support fallocate for non extent files. So we can update
662 		 * reserve space here.
663 		 */
664 		if ((retval > 0) &&
665 			(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
666 			ext4_da_update_reserve_space(inode, retval, 1);
667 	}
668 
669 	if (retval > 0) {
670 		unsigned int status;
671 
672 		if (unlikely(retval != map->m_len)) {
673 			ext4_warning(inode->i_sb,
674 				     "ES len assertion failed for inode "
675 				     "%lu: retval %d != map->m_len %d",
676 				     inode->i_ino, retval, map->m_len);
677 			WARN_ON(1);
678 		}
679 
680 		/*
681 		 * We have to zeroout blocks before inserting them into extent
682 		 * status tree. Otherwise someone could look them up there and
683 		 * use them before they are really zeroed. We also have to
684 		 * unmap metadata before zeroing as otherwise writeback can
685 		 * overwrite zeros with stale data from block device.
686 		 */
687 		if (flags & EXT4_GET_BLOCKS_ZERO &&
688 		    map->m_flags & EXT4_MAP_MAPPED &&
689 		    map->m_flags & EXT4_MAP_NEW) {
690 			ret = ext4_issue_zeroout(inode, map->m_lblk,
691 						 map->m_pblk, map->m_len);
692 			if (ret) {
693 				retval = ret;
694 				goto out_sem;
695 			}
696 		}
697 
698 		/*
699 		 * If the extent has been zeroed out, we don't need to update
700 		 * extent status tree.
701 		 */
702 		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
703 		    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
704 			if (ext4_es_is_written(&es))
705 				goto out_sem;
706 		}
707 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
708 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
709 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
710 		    !(status & EXTENT_STATUS_WRITTEN) &&
711 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
712 				       map->m_lblk + map->m_len - 1))
713 			status |= EXTENT_STATUS_DELAYED;
714 		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
715 					    map->m_pblk, status);
716 		if (ret < 0) {
717 			retval = ret;
718 			goto out_sem;
719 		}
720 	}
721 
722 out_sem:
723 	up_write((&EXT4_I(inode)->i_data_sem));
724 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
725 		ret = check_block_validity(inode, map);
726 		if (ret != 0)
727 			return ret;
728 
729 		/*
730 		 * Inodes with freshly allocated blocks where contents will be
731 		 * visible after transaction commit must be on transaction's
732 		 * ordered data list.
733 		 */
734 		if (map->m_flags & EXT4_MAP_NEW &&
735 		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
736 		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
737 		    !ext4_is_quota_file(inode) &&
738 		    ext4_should_order_data(inode)) {
739 			loff_t start_byte =
740 				(loff_t)map->m_lblk << inode->i_blkbits;
741 			loff_t length = (loff_t)map->m_len << inode->i_blkbits;
742 
743 			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
744 				ret = ext4_jbd2_inode_add_wait(handle, inode,
745 						start_byte, length);
746 			else
747 				ret = ext4_jbd2_inode_add_write(handle, inode,
748 						start_byte, length);
749 			if (ret)
750 				return ret;
751 		}
752 	}
753 	if (retval > 0 && (map->m_flags & EXT4_MAP_UNWRITTEN ||
754 				map->m_flags & EXT4_MAP_MAPPED))
755 		ext4_fc_track_range(handle, inode, map->m_lblk,
756 					map->m_lblk + map->m_len - 1);
757 	if (retval < 0)
758 		ext_debug(inode, "failed with err %d\n", retval);
759 	return retval;
760 }
761 
762 /*
763  * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
764  * we have to be careful as someone else may be manipulating b_state as well.
765  */
766 static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
767 {
768 	unsigned long old_state;
769 	unsigned long new_state;
770 
771 	flags &= EXT4_MAP_FLAGS;
772 
773 	/* Dummy buffer_head? Set non-atomically. */
774 	if (!bh->b_page) {
775 		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
776 		return;
777 	}
778 	/*
779 	 * Someone else may be modifying b_state. Be careful! This is ugly but
780 	 * once we get rid of using bh as a container for mapping information
781 	 * to pass to / from get_block functions, this can go away.
782 	 */
783 	do {
784 		old_state = READ_ONCE(bh->b_state);
785 		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
786 	} while (unlikely(
787 		 cmpxchg(&bh->b_state, old_state, new_state) != old_state));
788 }
789 
790 static int _ext4_get_block(struct inode *inode, sector_t iblock,
791 			   struct buffer_head *bh, int flags)
792 {
793 	struct ext4_map_blocks map;
794 	int ret = 0;
795 
796 	if (ext4_has_inline_data(inode))
797 		return -ERANGE;
798 
799 	map.m_lblk = iblock;
800 	map.m_len = bh->b_size >> inode->i_blkbits;
801 
802 	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
803 			      flags);
804 	if (ret > 0) {
805 		map_bh(bh, inode->i_sb, map.m_pblk);
806 		ext4_update_bh_state(bh, map.m_flags);
807 		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
808 		ret = 0;
809 	} else if (ret == 0) {
810 		/* hole case, need to fill in bh->b_size */
811 		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
812 	}
813 	return ret;
814 }
815 
816 int ext4_get_block(struct inode *inode, sector_t iblock,
817 		   struct buffer_head *bh, int create)
818 {
819 	return _ext4_get_block(inode, iblock, bh,
820 			       create ? EXT4_GET_BLOCKS_CREATE : 0);
821 }
822 
823 /*
824  * Get block function used when preparing for buffered write if we require
825  * creating an unwritten extent if blocks haven't been allocated.  The extent
826  * will be converted to written after the IO is complete.
827  */
828 int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
829 			     struct buffer_head *bh_result, int create)
830 {
831 	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
832 		   inode->i_ino, create);
833 	return _ext4_get_block(inode, iblock, bh_result,
834 			       EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
835 }
836 
837 /* Maximum number of blocks we map for direct IO at once. */
838 #define DIO_MAX_BLOCKS 4096
839 
840 /*
841  * `handle' can be NULL if create is zero
842  */
843 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
844 				ext4_lblk_t block, int map_flags)
845 {
846 	struct ext4_map_blocks map;
847 	struct buffer_head *bh;
848 	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
849 	bool nowait = map_flags & EXT4_GET_BLOCKS_CACHED_NOWAIT;
850 	int err;
851 
852 	ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
853 		    || handle != NULL || create == 0);
854 	ASSERT(create == 0 || !nowait);
855 
856 	map.m_lblk = block;
857 	map.m_len = 1;
858 	err = ext4_map_blocks(handle, inode, &map, map_flags);
859 
860 	if (err == 0)
861 		return create ? ERR_PTR(-ENOSPC) : NULL;
862 	if (err < 0)
863 		return ERR_PTR(err);
864 
865 	if (nowait)
866 		return sb_find_get_block(inode->i_sb, map.m_pblk);
867 
868 	bh = sb_getblk(inode->i_sb, map.m_pblk);
869 	if (unlikely(!bh))
870 		return ERR_PTR(-ENOMEM);
871 	if (map.m_flags & EXT4_MAP_NEW) {
872 		ASSERT(create != 0);
873 		ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
874 			    || (handle != NULL));
875 
876 		/*
877 		 * Now that we do not always journal data, we should
878 		 * keep in mind whether this should always journal the
879 		 * new buffer as metadata.  For now, regular file
880 		 * writes use ext4_get_block instead, so it's not a
881 		 * problem.
882 		 */
883 		lock_buffer(bh);
884 		BUFFER_TRACE(bh, "call get_create_access");
885 		err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
886 						     EXT4_JTR_NONE);
887 		if (unlikely(err)) {
888 			unlock_buffer(bh);
889 			goto errout;
890 		}
891 		if (!buffer_uptodate(bh)) {
892 			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
893 			set_buffer_uptodate(bh);
894 		}
895 		unlock_buffer(bh);
896 		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
897 		err = ext4_handle_dirty_metadata(handle, inode, bh);
898 		if (unlikely(err))
899 			goto errout;
900 	} else
901 		BUFFER_TRACE(bh, "not a new buffer");
902 	return bh;
903 errout:
904 	brelse(bh);
905 	return ERR_PTR(err);
906 }
907 
908 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
909 			       ext4_lblk_t block, int map_flags)
910 {
911 	struct buffer_head *bh;
912 	int ret;
913 
914 	bh = ext4_getblk(handle, inode, block, map_flags);
915 	if (IS_ERR(bh))
916 		return bh;
917 	if (!bh || ext4_buffer_uptodate(bh))
918 		return bh;
919 
920 	ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
921 	if (ret) {
922 		put_bh(bh);
923 		return ERR_PTR(ret);
924 	}
925 	return bh;
926 }
927 
928 /* Read a contiguous batch of blocks. */
929 int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
930 		     bool wait, struct buffer_head **bhs)
931 {
932 	int i, err;
933 
934 	for (i = 0; i < bh_count; i++) {
935 		bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
936 		if (IS_ERR(bhs[i])) {
937 			err = PTR_ERR(bhs[i]);
938 			bh_count = i;
939 			goto out_brelse;
940 		}
941 	}
942 
943 	for (i = 0; i < bh_count; i++)
944 		/* Note that NULL bhs[i] is valid because of holes. */
945 		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
946 			ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
947 
948 	if (!wait)
949 		return 0;
950 
951 	for (i = 0; i < bh_count; i++)
952 		if (bhs[i])
953 			wait_on_buffer(bhs[i]);
954 
955 	for (i = 0; i < bh_count; i++) {
956 		if (bhs[i] && !buffer_uptodate(bhs[i])) {
957 			err = -EIO;
958 			goto out_brelse;
959 		}
960 	}
961 	return 0;
962 
963 out_brelse:
964 	for (i = 0; i < bh_count; i++) {
965 		brelse(bhs[i]);
966 		bhs[i] = NULL;
967 	}
968 	return err;
969 }
970 
971 int ext4_walk_page_buffers(handle_t *handle, struct inode *inode,
972 			   struct buffer_head *head,
973 			   unsigned from,
974 			   unsigned to,
975 			   int *partial,
976 			   int (*fn)(handle_t *handle, struct inode *inode,
977 				     struct buffer_head *bh))
978 {
979 	struct buffer_head *bh;
980 	unsigned block_start, block_end;
981 	unsigned blocksize = head->b_size;
982 	int err, ret = 0;
983 	struct buffer_head *next;
984 
985 	for (bh = head, block_start = 0;
986 	     ret == 0 && (bh != head || !block_start);
987 	     block_start = block_end, bh = next) {
988 		next = bh->b_this_page;
989 		block_end = block_start + blocksize;
990 		if (block_end <= from || block_start >= to) {
991 			if (partial && !buffer_uptodate(bh))
992 				*partial = 1;
993 			continue;
994 		}
995 		err = (*fn)(handle, inode, bh);
996 		if (!ret)
997 			ret = err;
998 	}
999 	return ret;
1000 }
1001 
1002 /*
1003  * To preserve ordering, it is essential that the hole instantiation and
1004  * the data write be encapsulated in a single transaction.  We cannot
1005  * close off a transaction and start a new one between the ext4_get_block()
1006  * and the commit_write().  So doing the jbd2_journal_start at the start of
1007  * prepare_write() is the right place.
1008  *
1009  * Also, this function can nest inside ext4_writepage().  In that case, we
1010  * *know* that ext4_writepage() has generated enough buffer credits to do the
1011  * whole page.  So we won't block on the journal in that case, which is good,
1012  * because the caller may be PF_MEMALLOC.
1013  *
1014  * By accident, ext4 can be reentered when a transaction is open via
1015  * quota file writes.  If we were to commit the transaction while thus
1016  * reentered, there can be a deadlock - we would be holding a quota
1017  * lock, and the commit would never complete if another thread had a
1018  * transaction open and was blocking on the quota lock - a ranking
1019  * violation.
1020  *
1021  * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1022  * will _not_ run commit under these circumstances because handle->h_ref
1023  * is elevated.  We'll still have enough credits for the tiny quotafile
1024  * write.
1025  */
1026 int do_journal_get_write_access(handle_t *handle, struct inode *inode,
1027 				struct buffer_head *bh)
1028 {
1029 	int dirty = buffer_dirty(bh);
1030 	int ret;
1031 
1032 	if (!buffer_mapped(bh) || buffer_freed(bh))
1033 		return 0;
1034 	/*
1035 	 * __block_write_begin() could have dirtied some buffers. Clean
1036 	 * the dirty bit as jbd2_journal_get_write_access() could complain
1037 	 * otherwise about fs integrity issues. Setting of the dirty bit
1038 	 * by __block_write_begin() isn't a real problem here as we clear
1039 	 * the bit before releasing a page lock and thus writeback cannot
1040 	 * ever write the buffer.
1041 	 */
1042 	if (dirty)
1043 		clear_buffer_dirty(bh);
1044 	BUFFER_TRACE(bh, "get write access");
1045 	ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1046 					    EXT4_JTR_NONE);
1047 	if (!ret && dirty)
1048 		ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1049 	return ret;
1050 }
1051 
1052 #ifdef CONFIG_FS_ENCRYPTION
1053 static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
1054 				  get_block_t *get_block)
1055 {
1056 	unsigned from = pos & (PAGE_SIZE - 1);
1057 	unsigned to = from + len;
1058 	struct inode *inode = page->mapping->host;
1059 	unsigned block_start, block_end;
1060 	sector_t block;
1061 	int err = 0;
1062 	unsigned blocksize = inode->i_sb->s_blocksize;
1063 	unsigned bbits;
1064 	struct buffer_head *bh, *head, *wait[2];
1065 	int nr_wait = 0;
1066 	int i;
1067 
1068 	BUG_ON(!PageLocked(page));
1069 	BUG_ON(from > PAGE_SIZE);
1070 	BUG_ON(to > PAGE_SIZE);
1071 	BUG_ON(from > to);
1072 
1073 	if (!page_has_buffers(page))
1074 		create_empty_buffers(page, blocksize, 0);
1075 	head = page_buffers(page);
1076 	bbits = ilog2(blocksize);
1077 	block = (sector_t)page->index << (PAGE_SHIFT - bbits);
1078 
1079 	for (bh = head, block_start = 0; bh != head || !block_start;
1080 	    block++, block_start = block_end, bh = bh->b_this_page) {
1081 		block_end = block_start + blocksize;
1082 		if (block_end <= from || block_start >= to) {
1083 			if (PageUptodate(page)) {
1084 				set_buffer_uptodate(bh);
1085 			}
1086 			continue;
1087 		}
1088 		if (buffer_new(bh))
1089 			clear_buffer_new(bh);
1090 		if (!buffer_mapped(bh)) {
1091 			WARN_ON(bh->b_size != blocksize);
1092 			err = get_block(inode, block, bh, 1);
1093 			if (err)
1094 				break;
1095 			if (buffer_new(bh)) {
1096 				if (PageUptodate(page)) {
1097 					clear_buffer_new(bh);
1098 					set_buffer_uptodate(bh);
1099 					mark_buffer_dirty(bh);
1100 					continue;
1101 				}
1102 				if (block_end > to || block_start < from)
1103 					zero_user_segments(page, to, block_end,
1104 							   block_start, from);
1105 				continue;
1106 			}
1107 		}
1108 		if (PageUptodate(page)) {
1109 			set_buffer_uptodate(bh);
1110 			continue;
1111 		}
1112 		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1113 		    !buffer_unwritten(bh) &&
1114 		    (block_start < from || block_end > to)) {
1115 			ext4_read_bh_lock(bh, 0, false);
1116 			wait[nr_wait++] = bh;
1117 		}
1118 	}
1119 	/*
1120 	 * If we issued read requests, let them complete.
1121 	 */
1122 	for (i = 0; i < nr_wait; i++) {
1123 		wait_on_buffer(wait[i]);
1124 		if (!buffer_uptodate(wait[i]))
1125 			err = -EIO;
1126 	}
1127 	if (unlikely(err)) {
1128 		page_zero_new_buffers(page, from, to);
1129 	} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1130 		for (i = 0; i < nr_wait; i++) {
1131 			int err2;
1132 
1133 			err2 = fscrypt_decrypt_pagecache_blocks(page, blocksize,
1134 								bh_offset(wait[i]));
1135 			if (err2) {
1136 				clear_buffer_uptodate(wait[i]);
1137 				err = err2;
1138 			}
1139 		}
1140 	}
1141 
1142 	return err;
1143 }
1144 #endif
1145 
1146 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1147 			    loff_t pos, unsigned len,
1148 			    struct page **pagep, void **fsdata)
1149 {
1150 	struct inode *inode = mapping->host;
1151 	int ret, needed_blocks;
1152 	handle_t *handle;
1153 	int retries = 0;
1154 	struct page *page;
1155 	pgoff_t index;
1156 	unsigned from, to;
1157 
1158 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
1159 		return -EIO;
1160 
1161 	trace_ext4_write_begin(inode, pos, len);
1162 	/*
1163 	 * Reserve one block more for addition to orphan list in case
1164 	 * we allocate blocks but write fails for some reason
1165 	 */
1166 	needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1167 	index = pos >> PAGE_SHIFT;
1168 	from = pos & (PAGE_SIZE - 1);
1169 	to = from + len;
1170 
1171 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1172 		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1173 						    pagep);
1174 		if (ret < 0)
1175 			return ret;
1176 		if (ret == 1)
1177 			return 0;
1178 	}
1179 
1180 	/*
1181 	 * grab_cache_page_write_begin() can take a long time if the
1182 	 * system is thrashing due to memory pressure, or if the page
1183 	 * is being written back.  So grab it first before we start
1184 	 * the transaction handle.  This also allows us to allocate
1185 	 * the page (if needed) without using GFP_NOFS.
1186 	 */
1187 retry_grab:
1188 	page = grab_cache_page_write_begin(mapping, index);
1189 	if (!page)
1190 		return -ENOMEM;
1191 	unlock_page(page);
1192 
1193 retry_journal:
1194 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1195 	if (IS_ERR(handle)) {
1196 		put_page(page);
1197 		return PTR_ERR(handle);
1198 	}
1199 
1200 	lock_page(page);
1201 	if (page->mapping != mapping) {
1202 		/* The page got truncated from under us */
1203 		unlock_page(page);
1204 		put_page(page);
1205 		ext4_journal_stop(handle);
1206 		goto retry_grab;
1207 	}
1208 	/* In case writeback began while the page was unlocked */
1209 	wait_for_stable_page(page);
1210 
1211 #ifdef CONFIG_FS_ENCRYPTION
1212 	if (ext4_should_dioread_nolock(inode))
1213 		ret = ext4_block_write_begin(page, pos, len,
1214 					     ext4_get_block_unwritten);
1215 	else
1216 		ret = ext4_block_write_begin(page, pos, len,
1217 					     ext4_get_block);
1218 #else
1219 	if (ext4_should_dioread_nolock(inode))
1220 		ret = __block_write_begin(page, pos, len,
1221 					  ext4_get_block_unwritten);
1222 	else
1223 		ret = __block_write_begin(page, pos, len, ext4_get_block);
1224 #endif
1225 	if (!ret && ext4_should_journal_data(inode)) {
1226 		ret = ext4_walk_page_buffers(handle, inode,
1227 					     page_buffers(page), from, to, NULL,
1228 					     do_journal_get_write_access);
1229 	}
1230 
1231 	if (ret) {
1232 		bool extended = (pos + len > inode->i_size) &&
1233 				!ext4_verity_in_progress(inode);
1234 
1235 		unlock_page(page);
1236 		/*
1237 		 * __block_write_begin may have instantiated a few blocks
1238 		 * outside i_size.  Trim these off again. Don't need
1239 		 * i_size_read because we hold i_rwsem.
1240 		 *
1241 		 * Add inode to orphan list in case we crash before
1242 		 * truncate finishes
1243 		 */
1244 		if (extended && ext4_can_truncate(inode))
1245 			ext4_orphan_add(handle, inode);
1246 
1247 		ext4_journal_stop(handle);
1248 		if (extended) {
1249 			ext4_truncate_failed_write(inode);
1250 			/*
1251 			 * If truncate failed early the inode might
1252 			 * still be on the orphan list; we need to
1253 			 * make sure the inode is removed from the
1254 			 * orphan list in that case.
1255 			 */
1256 			if (inode->i_nlink)
1257 				ext4_orphan_del(NULL, inode);
1258 		}
1259 
1260 		if (ret == -ENOSPC &&
1261 		    ext4_should_retry_alloc(inode->i_sb, &retries))
1262 			goto retry_journal;
1263 		put_page(page);
1264 		return ret;
1265 	}
1266 	*pagep = page;
1267 	return ret;
1268 }
1269 
1270 /* For write_end() in data=journal mode */
1271 static int write_end_fn(handle_t *handle, struct inode *inode,
1272 			struct buffer_head *bh)
1273 {
1274 	int ret;
1275 	if (!buffer_mapped(bh) || buffer_freed(bh))
1276 		return 0;
1277 	set_buffer_uptodate(bh);
1278 	ret = ext4_handle_dirty_metadata(handle, NULL, bh);
1279 	clear_buffer_meta(bh);
1280 	clear_buffer_prio(bh);
1281 	return ret;
1282 }
1283 
1284 /*
1285  * We need to pick up the new inode size which generic_commit_write gave us
1286  * `file' can be NULL - eg, when called from page_symlink().
1287  *
1288  * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1289  * buffers are managed internally.
1290  */
1291 static int ext4_write_end(struct file *file,
1292 			  struct address_space *mapping,
1293 			  loff_t pos, unsigned len, unsigned copied,
1294 			  struct page *page, void *fsdata)
1295 {
1296 	handle_t *handle = ext4_journal_current_handle();
1297 	struct inode *inode = mapping->host;
1298 	loff_t old_size = inode->i_size;
1299 	int ret = 0, ret2;
1300 	int i_size_changed = 0;
1301 	bool verity = ext4_verity_in_progress(inode);
1302 
1303 	trace_ext4_write_end(inode, pos, len, copied);
1304 
1305 	if (ext4_has_inline_data(inode))
1306 		return ext4_write_inline_data_end(inode, pos, len, copied, page);
1307 
1308 	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1309 	/*
1310 	 * it's important to update i_size while still holding page lock:
1311 	 * page writeout could otherwise come in and zero beyond i_size.
1312 	 *
1313 	 * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1314 	 * blocks are being written past EOF, so skip the i_size update.
1315 	 */
1316 	if (!verity)
1317 		i_size_changed = ext4_update_inode_size(inode, pos + copied);
1318 	unlock_page(page);
1319 	put_page(page);
1320 
1321 	if (old_size < pos && !verity)
1322 		pagecache_isize_extended(inode, old_size, pos);
1323 	/*
1324 	 * Don't mark the inode dirty under page lock. First, it unnecessarily
1325 	 * makes the holding time of page lock longer. Second, it forces lock
1326 	 * ordering of page lock and transaction start for journaling
1327 	 * filesystems.
1328 	 */
1329 	if (i_size_changed)
1330 		ret = ext4_mark_inode_dirty(handle, inode);
1331 
1332 	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1333 		/* if we have allocated more blocks and copied
1334 		 * less. We will have blocks allocated outside
1335 		 * inode->i_size. So truncate them
1336 		 */
1337 		ext4_orphan_add(handle, inode);
1338 
1339 	ret2 = ext4_journal_stop(handle);
1340 	if (!ret)
1341 		ret = ret2;
1342 
1343 	if (pos + len > inode->i_size && !verity) {
1344 		ext4_truncate_failed_write(inode);
1345 		/*
1346 		 * If truncate failed early the inode might still be
1347 		 * on the orphan list; we need to make sure the inode
1348 		 * is removed from the orphan list in that case.
1349 		 */
1350 		if (inode->i_nlink)
1351 			ext4_orphan_del(NULL, inode);
1352 	}
1353 
1354 	return ret ? ret : copied;
1355 }
1356 
1357 /*
1358  * This is a private version of page_zero_new_buffers() which doesn't
1359  * set the buffer to be dirty, since in data=journalled mode we need
1360  * to call ext4_handle_dirty_metadata() instead.
1361  */
1362 static void ext4_journalled_zero_new_buffers(handle_t *handle,
1363 					    struct inode *inode,
1364 					    struct page *page,
1365 					    unsigned from, unsigned to)
1366 {
1367 	unsigned int block_start = 0, block_end;
1368 	struct buffer_head *head, *bh;
1369 
1370 	bh = head = page_buffers(page);
1371 	do {
1372 		block_end = block_start + bh->b_size;
1373 		if (buffer_new(bh)) {
1374 			if (block_end > from && block_start < to) {
1375 				if (!PageUptodate(page)) {
1376 					unsigned start, size;
1377 
1378 					start = max(from, block_start);
1379 					size = min(to, block_end) - start;
1380 
1381 					zero_user(page, start, size);
1382 					write_end_fn(handle, inode, bh);
1383 				}
1384 				clear_buffer_new(bh);
1385 			}
1386 		}
1387 		block_start = block_end;
1388 		bh = bh->b_this_page;
1389 	} while (bh != head);
1390 }
1391 
1392 static int ext4_journalled_write_end(struct file *file,
1393 				     struct address_space *mapping,
1394 				     loff_t pos, unsigned len, unsigned copied,
1395 				     struct page *page, void *fsdata)
1396 {
1397 	handle_t *handle = ext4_journal_current_handle();
1398 	struct inode *inode = mapping->host;
1399 	loff_t old_size = inode->i_size;
1400 	int ret = 0, ret2;
1401 	int partial = 0;
1402 	unsigned from, to;
1403 	int size_changed = 0;
1404 	bool verity = ext4_verity_in_progress(inode);
1405 
1406 	trace_ext4_journalled_write_end(inode, pos, len, copied);
1407 	from = pos & (PAGE_SIZE - 1);
1408 	to = from + len;
1409 
1410 	BUG_ON(!ext4_handle_valid(handle));
1411 
1412 	if (ext4_has_inline_data(inode))
1413 		return ext4_write_inline_data_end(inode, pos, len, copied, page);
1414 
1415 	if (unlikely(copied < len) && !PageUptodate(page)) {
1416 		copied = 0;
1417 		ext4_journalled_zero_new_buffers(handle, inode, page, from, to);
1418 	} else {
1419 		if (unlikely(copied < len))
1420 			ext4_journalled_zero_new_buffers(handle, inode, page,
1421 							 from + copied, to);
1422 		ret = ext4_walk_page_buffers(handle, inode, page_buffers(page),
1423 					     from, from + copied, &partial,
1424 					     write_end_fn);
1425 		if (!partial)
1426 			SetPageUptodate(page);
1427 	}
1428 	if (!verity)
1429 		size_changed = ext4_update_inode_size(inode, pos + copied);
1430 	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1431 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1432 	unlock_page(page);
1433 	put_page(page);
1434 
1435 	if (old_size < pos && !verity)
1436 		pagecache_isize_extended(inode, old_size, pos);
1437 
1438 	if (size_changed) {
1439 		ret2 = ext4_mark_inode_dirty(handle, inode);
1440 		if (!ret)
1441 			ret = ret2;
1442 	}
1443 
1444 	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1445 		/* if we have allocated more blocks and copied
1446 		 * less. We will have blocks allocated outside
1447 		 * inode->i_size. So truncate them
1448 		 */
1449 		ext4_orphan_add(handle, inode);
1450 
1451 	ret2 = ext4_journal_stop(handle);
1452 	if (!ret)
1453 		ret = ret2;
1454 	if (pos + len > inode->i_size && !verity) {
1455 		ext4_truncate_failed_write(inode);
1456 		/*
1457 		 * If truncate failed early the inode might still be
1458 		 * on the orphan list; we need to make sure the inode
1459 		 * is removed from the orphan list in that case.
1460 		 */
1461 		if (inode->i_nlink)
1462 			ext4_orphan_del(NULL, inode);
1463 	}
1464 
1465 	return ret ? ret : copied;
1466 }
1467 
1468 /*
1469  * Reserve space for a single cluster
1470  */
1471 static int ext4_da_reserve_space(struct inode *inode)
1472 {
1473 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1474 	struct ext4_inode_info *ei = EXT4_I(inode);
1475 	int ret;
1476 
1477 	/*
1478 	 * We will charge metadata quota at writeout time; this saves
1479 	 * us from metadata over-estimation, though we may go over by
1480 	 * a small amount in the end.  Here we just reserve for data.
1481 	 */
1482 	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1483 	if (ret)
1484 		return ret;
1485 
1486 	spin_lock(&ei->i_block_reservation_lock);
1487 	if (ext4_claim_free_clusters(sbi, 1, 0)) {
1488 		spin_unlock(&ei->i_block_reservation_lock);
1489 		dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1490 		return -ENOSPC;
1491 	}
1492 	ei->i_reserved_data_blocks++;
1493 	trace_ext4_da_reserve_space(inode);
1494 	spin_unlock(&ei->i_block_reservation_lock);
1495 
1496 	return 0;       /* success */
1497 }
1498 
1499 void ext4_da_release_space(struct inode *inode, int to_free)
1500 {
1501 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1502 	struct ext4_inode_info *ei = EXT4_I(inode);
1503 
1504 	if (!to_free)
1505 		return;		/* Nothing to release, exit */
1506 
1507 	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1508 
1509 	trace_ext4_da_release_space(inode, to_free);
1510 	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1511 		/*
1512 		 * if there aren't enough reserved blocks, then the
1513 		 * counter is messed up somewhere.  Since this
1514 		 * function is called from invalidate page, it's
1515 		 * harmless to return without any action.
1516 		 */
1517 		ext4_warning(inode->i_sb, "ext4_da_release_space: "
1518 			 "ino %lu, to_free %d with only %d reserved "
1519 			 "data blocks", inode->i_ino, to_free,
1520 			 ei->i_reserved_data_blocks);
1521 		WARN_ON(1);
1522 		to_free = ei->i_reserved_data_blocks;
1523 	}
1524 	ei->i_reserved_data_blocks -= to_free;
1525 
1526 	/* update fs dirty data blocks counter */
1527 	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1528 
1529 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1530 
1531 	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1532 }
1533 
1534 /*
1535  * Delayed allocation stuff
1536  */
1537 
1538 struct mpage_da_data {
1539 	struct inode *inode;
1540 	struct writeback_control *wbc;
1541 
1542 	pgoff_t first_page;	/* The first page to write */
1543 	pgoff_t next_page;	/* Current page to examine */
1544 	pgoff_t last_page;	/* Last page to examine */
1545 	/*
1546 	 * Extent to map - this can be after first_page because that can be
1547 	 * fully mapped. We somewhat abuse m_flags to store whether the extent
1548 	 * is delalloc or unwritten.
1549 	 */
1550 	struct ext4_map_blocks map;
1551 	struct ext4_io_submit io_submit;	/* IO submission data */
1552 	unsigned int do_map:1;
1553 	unsigned int scanned_until_end:1;
1554 };
1555 
1556 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1557 				       bool invalidate)
1558 {
1559 	unsigned nr, i;
1560 	pgoff_t index, end;
1561 	struct folio_batch fbatch;
1562 	struct inode *inode = mpd->inode;
1563 	struct address_space *mapping = inode->i_mapping;
1564 
1565 	/* This is necessary when next_page == 0. */
1566 	if (mpd->first_page >= mpd->next_page)
1567 		return;
1568 
1569 	mpd->scanned_until_end = 0;
1570 	index = mpd->first_page;
1571 	end   = mpd->next_page - 1;
1572 	if (invalidate) {
1573 		ext4_lblk_t start, last;
1574 		start = index << (PAGE_SHIFT - inode->i_blkbits);
1575 		last = end << (PAGE_SHIFT - inode->i_blkbits);
1576 
1577 		/*
1578 		 * avoid racing with extent status tree scans made by
1579 		 * ext4_insert_delayed_block()
1580 		 */
1581 		down_write(&EXT4_I(inode)->i_data_sem);
1582 		ext4_es_remove_extent(inode, start, last - start + 1);
1583 		up_write(&EXT4_I(inode)->i_data_sem);
1584 	}
1585 
1586 	folio_batch_init(&fbatch);
1587 	while (index <= end) {
1588 		nr = filemap_get_folios(mapping, &index, end, &fbatch);
1589 		if (nr == 0)
1590 			break;
1591 		for (i = 0; i < nr; i++) {
1592 			struct folio *folio = fbatch.folios[i];
1593 
1594 			if (folio->index < mpd->first_page)
1595 				continue;
1596 			if (folio->index + folio_nr_pages(folio) - 1 > end)
1597 				continue;
1598 			BUG_ON(!folio_test_locked(folio));
1599 			BUG_ON(folio_test_writeback(folio));
1600 			if (invalidate) {
1601 				if (folio_mapped(folio))
1602 					folio_clear_dirty_for_io(folio);
1603 				block_invalidate_folio(folio, 0,
1604 						folio_size(folio));
1605 				folio_clear_uptodate(folio);
1606 			}
1607 			folio_unlock(folio);
1608 		}
1609 		folio_batch_release(&fbatch);
1610 	}
1611 }
1612 
1613 static void ext4_print_free_blocks(struct inode *inode)
1614 {
1615 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1616 	struct super_block *sb = inode->i_sb;
1617 	struct ext4_inode_info *ei = EXT4_I(inode);
1618 
1619 	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1620 	       EXT4_C2B(EXT4_SB(inode->i_sb),
1621 			ext4_count_free_clusters(sb)));
1622 	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1623 	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1624 	       (long long) EXT4_C2B(EXT4_SB(sb),
1625 		percpu_counter_sum(&sbi->s_freeclusters_counter)));
1626 	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1627 	       (long long) EXT4_C2B(EXT4_SB(sb),
1628 		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1629 	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1630 	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1631 		 ei->i_reserved_data_blocks);
1632 	return;
1633 }
1634 
1635 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct inode *inode,
1636 				      struct buffer_head *bh)
1637 {
1638 	return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
1639 }
1640 
1641 /*
1642  * ext4_insert_delayed_block - adds a delayed block to the extents status
1643  *                             tree, incrementing the reserved cluster/block
1644  *                             count or making a pending reservation
1645  *                             where needed
1646  *
1647  * @inode - file containing the newly added block
1648  * @lblk - logical block to be added
1649  *
1650  * Returns 0 on success, negative error code on failure.
1651  */
1652 static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
1653 {
1654 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1655 	int ret;
1656 	bool allocated = false;
1657 	bool reserved = false;
1658 
1659 	/*
1660 	 * If the cluster containing lblk is shared with a delayed,
1661 	 * written, or unwritten extent in a bigalloc file system, it's
1662 	 * already been accounted for and does not need to be reserved.
1663 	 * A pending reservation must be made for the cluster if it's
1664 	 * shared with a written or unwritten extent and doesn't already
1665 	 * have one.  Written and unwritten extents can be purged from the
1666 	 * extents status tree if the system is under memory pressure, so
1667 	 * it's necessary to examine the extent tree if a search of the
1668 	 * extents status tree doesn't get a match.
1669 	 */
1670 	if (sbi->s_cluster_ratio == 1) {
1671 		ret = ext4_da_reserve_space(inode);
1672 		if (ret != 0)   /* ENOSPC */
1673 			goto errout;
1674 		reserved = true;
1675 	} else {   /* bigalloc */
1676 		if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
1677 			if (!ext4_es_scan_clu(inode,
1678 					      &ext4_es_is_mapped, lblk)) {
1679 				ret = ext4_clu_mapped(inode,
1680 						      EXT4_B2C(sbi, lblk));
1681 				if (ret < 0)
1682 					goto errout;
1683 				if (ret == 0) {
1684 					ret = ext4_da_reserve_space(inode);
1685 					if (ret != 0)   /* ENOSPC */
1686 						goto errout;
1687 					reserved = true;
1688 				} else {
1689 					allocated = true;
1690 				}
1691 			} else {
1692 				allocated = true;
1693 			}
1694 		}
1695 	}
1696 
1697 	ret = ext4_es_insert_delayed_block(inode, lblk, allocated);
1698 	if (ret && reserved)
1699 		ext4_da_release_space(inode, 1);
1700 
1701 errout:
1702 	return ret;
1703 }
1704 
1705 /*
1706  * This function is grabs code from the very beginning of
1707  * ext4_map_blocks, but assumes that the caller is from delayed write
1708  * time. This function looks up the requested blocks and sets the
1709  * buffer delay bit under the protection of i_data_sem.
1710  */
1711 static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1712 			      struct ext4_map_blocks *map,
1713 			      struct buffer_head *bh)
1714 {
1715 	struct extent_status es;
1716 	int retval;
1717 	sector_t invalid_block = ~((sector_t) 0xffff);
1718 #ifdef ES_AGGRESSIVE_TEST
1719 	struct ext4_map_blocks orig_map;
1720 
1721 	memcpy(&orig_map, map, sizeof(*map));
1722 #endif
1723 
1724 	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1725 		invalid_block = ~0;
1726 
1727 	map->m_flags = 0;
1728 	ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1729 		  (unsigned long) map->m_lblk);
1730 
1731 	/* Lookup extent status tree firstly */
1732 	if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
1733 		if (ext4_es_is_hole(&es)) {
1734 			retval = 0;
1735 			down_read(&EXT4_I(inode)->i_data_sem);
1736 			goto add_delayed;
1737 		}
1738 
1739 		/*
1740 		 * Delayed extent could be allocated by fallocate.
1741 		 * So we need to check it.
1742 		 */
1743 		if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1744 			map_bh(bh, inode->i_sb, invalid_block);
1745 			set_buffer_new(bh);
1746 			set_buffer_delay(bh);
1747 			return 0;
1748 		}
1749 
1750 		map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1751 		retval = es.es_len - (iblock - es.es_lblk);
1752 		if (retval > map->m_len)
1753 			retval = map->m_len;
1754 		map->m_len = retval;
1755 		if (ext4_es_is_written(&es))
1756 			map->m_flags |= EXT4_MAP_MAPPED;
1757 		else if (ext4_es_is_unwritten(&es))
1758 			map->m_flags |= EXT4_MAP_UNWRITTEN;
1759 		else
1760 			BUG();
1761 
1762 #ifdef ES_AGGRESSIVE_TEST
1763 		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1764 #endif
1765 		return retval;
1766 	}
1767 
1768 	/*
1769 	 * Try to see if we can get the block without requesting a new
1770 	 * file system block.
1771 	 */
1772 	down_read(&EXT4_I(inode)->i_data_sem);
1773 	if (ext4_has_inline_data(inode))
1774 		retval = 0;
1775 	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1776 		retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1777 	else
1778 		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1779 
1780 add_delayed:
1781 	if (retval == 0) {
1782 		int ret;
1783 
1784 		/*
1785 		 * XXX: __block_prepare_write() unmaps passed block,
1786 		 * is it OK?
1787 		 */
1788 
1789 		ret = ext4_insert_delayed_block(inode, map->m_lblk);
1790 		if (ret != 0) {
1791 			retval = ret;
1792 			goto out_unlock;
1793 		}
1794 
1795 		map_bh(bh, inode->i_sb, invalid_block);
1796 		set_buffer_new(bh);
1797 		set_buffer_delay(bh);
1798 	} else if (retval > 0) {
1799 		int ret;
1800 		unsigned int status;
1801 
1802 		if (unlikely(retval != map->m_len)) {
1803 			ext4_warning(inode->i_sb,
1804 				     "ES len assertion failed for inode "
1805 				     "%lu: retval %d != map->m_len %d",
1806 				     inode->i_ino, retval, map->m_len);
1807 			WARN_ON(1);
1808 		}
1809 
1810 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1811 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1812 		ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1813 					    map->m_pblk, status);
1814 		if (ret != 0)
1815 			retval = ret;
1816 	}
1817 
1818 out_unlock:
1819 	up_read((&EXT4_I(inode)->i_data_sem));
1820 
1821 	return retval;
1822 }
1823 
1824 /*
1825  * This is a special get_block_t callback which is used by
1826  * ext4_da_write_begin().  It will either return mapped block or
1827  * reserve space for a single block.
1828  *
1829  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1830  * We also have b_blocknr = -1 and b_bdev initialized properly
1831  *
1832  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1833  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1834  * initialized properly.
1835  */
1836 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1837 			   struct buffer_head *bh, int create)
1838 {
1839 	struct ext4_map_blocks map;
1840 	int ret = 0;
1841 
1842 	BUG_ON(create == 0);
1843 	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1844 
1845 	map.m_lblk = iblock;
1846 	map.m_len = 1;
1847 
1848 	/*
1849 	 * first, we need to know whether the block is allocated already
1850 	 * preallocated blocks are unmapped but should treated
1851 	 * the same as allocated blocks.
1852 	 */
1853 	ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1854 	if (ret <= 0)
1855 		return ret;
1856 
1857 	map_bh(bh, inode->i_sb, map.m_pblk);
1858 	ext4_update_bh_state(bh, map.m_flags);
1859 
1860 	if (buffer_unwritten(bh)) {
1861 		/* A delayed write to unwritten bh should be marked
1862 		 * new and mapped.  Mapped ensures that we don't do
1863 		 * get_block multiple times when we write to the same
1864 		 * offset and new ensures that we do proper zero out
1865 		 * for partial write.
1866 		 */
1867 		set_buffer_new(bh);
1868 		set_buffer_mapped(bh);
1869 	}
1870 	return 0;
1871 }
1872 
1873 static int __ext4_journalled_writepage(struct page *page,
1874 				       unsigned int len)
1875 {
1876 	struct address_space *mapping = page->mapping;
1877 	struct inode *inode = mapping->host;
1878 	handle_t *handle = NULL;
1879 	int ret = 0, err = 0;
1880 	int inline_data = ext4_has_inline_data(inode);
1881 	struct buffer_head *inode_bh = NULL;
1882 	loff_t size;
1883 
1884 	ClearPageChecked(page);
1885 
1886 	if (inline_data) {
1887 		BUG_ON(page->index != 0);
1888 		BUG_ON(len > ext4_get_max_inline_size(inode));
1889 		inode_bh = ext4_journalled_write_inline_data(inode, len, page);
1890 		if (inode_bh == NULL)
1891 			goto out;
1892 	}
1893 	/*
1894 	 * We need to release the page lock before we start the
1895 	 * journal, so grab a reference so the page won't disappear
1896 	 * out from under us.
1897 	 */
1898 	get_page(page);
1899 	unlock_page(page);
1900 
1901 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
1902 				    ext4_writepage_trans_blocks(inode));
1903 	if (IS_ERR(handle)) {
1904 		ret = PTR_ERR(handle);
1905 		put_page(page);
1906 		goto out_no_pagelock;
1907 	}
1908 	BUG_ON(!ext4_handle_valid(handle));
1909 
1910 	lock_page(page);
1911 	put_page(page);
1912 	size = i_size_read(inode);
1913 	if (page->mapping != mapping || page_offset(page) > size) {
1914 		/* The page got truncated from under us */
1915 		ext4_journal_stop(handle);
1916 		ret = 0;
1917 		goto out;
1918 	}
1919 
1920 	if (inline_data) {
1921 		ret = ext4_mark_inode_dirty(handle, inode);
1922 	} else {
1923 		struct buffer_head *page_bufs = page_buffers(page);
1924 
1925 		if (page->index == size >> PAGE_SHIFT)
1926 			len = size & ~PAGE_MASK;
1927 		else
1928 			len = PAGE_SIZE;
1929 
1930 		ret = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1931 					     NULL, do_journal_get_write_access);
1932 
1933 		err = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
1934 					     NULL, write_end_fn);
1935 	}
1936 	if (ret == 0)
1937 		ret = err;
1938 	err = ext4_jbd2_inode_add_write(handle, inode, page_offset(page), len);
1939 	if (ret == 0)
1940 		ret = err;
1941 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1942 	err = ext4_journal_stop(handle);
1943 	if (!ret)
1944 		ret = err;
1945 
1946 	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
1947 out:
1948 	unlock_page(page);
1949 out_no_pagelock:
1950 	brelse(inode_bh);
1951 	return ret;
1952 }
1953 
1954 /*
1955  * Note that we don't need to start a transaction unless we're journaling data
1956  * because we should have holes filled from ext4_page_mkwrite(). We even don't
1957  * need to file the inode to the transaction's list in ordered mode because if
1958  * we are writing back data added by write(), the inode is already there and if
1959  * we are writing back data modified via mmap(), no one guarantees in which
1960  * transaction the data will hit the disk. In case we are journaling data, we
1961  * cannot start transaction directly because transaction start ranks above page
1962  * lock so we have to do some magic.
1963  *
1964  * This function can get called via...
1965  *   - ext4_writepages after taking page lock (have journal handle)
1966  *   - journal_submit_inode_data_buffers (no journal handle)
1967  *   - shrink_page_list via the kswapd/direct reclaim (no journal handle)
1968  *   - grab_page_cache when doing write_begin (have journal handle)
1969  *
1970  * We don't do any block allocation in this function. If we have page with
1971  * multiple blocks we need to write those buffer_heads that are mapped. This
1972  * is important for mmaped based write. So if we do with blocksize 1K
1973  * truncate(f, 1024);
1974  * a = mmap(f, 0, 4096);
1975  * a[0] = 'a';
1976  * truncate(f, 4096);
1977  * we have in the page first buffer_head mapped via page_mkwrite call back
1978  * but other buffer_heads would be unmapped but dirty (dirty done via the
1979  * do_wp_page). So writepage should write the first block. If we modify
1980  * the mmap area beyond 1024 we will again get a page_fault and the
1981  * page_mkwrite callback will do the block allocation and mark the
1982  * buffer_heads mapped.
1983  *
1984  * We redirty the page if we have any buffer_heads that is either delay or
1985  * unwritten in the page.
1986  *
1987  * We can get recursively called as show below.
1988  *
1989  *	ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1990  *		ext4_writepage()
1991  *
1992  * But since we don't do any block allocation we should not deadlock.
1993  * Page also have the dirty flag cleared so we don't get recurive page_lock.
1994  */
1995 static int ext4_writepage(struct page *page,
1996 			  struct writeback_control *wbc)
1997 {
1998 	struct folio *folio = page_folio(page);
1999 	int ret = 0;
2000 	loff_t size;
2001 	unsigned int len;
2002 	struct buffer_head *page_bufs = NULL;
2003 	struct inode *inode = page->mapping->host;
2004 	struct ext4_io_submit io_submit;
2005 	bool keep_towrite = false;
2006 
2007 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
2008 		folio_invalidate(folio, 0, folio_size(folio));
2009 		folio_unlock(folio);
2010 		return -EIO;
2011 	}
2012 
2013 	trace_ext4_writepage(page);
2014 	size = i_size_read(inode);
2015 	if (page->index == size >> PAGE_SHIFT &&
2016 	    !ext4_verity_in_progress(inode))
2017 		len = size & ~PAGE_MASK;
2018 	else
2019 		len = PAGE_SIZE;
2020 
2021 	/* Should never happen but for bugs in other kernel subsystems */
2022 	if (!page_has_buffers(page)) {
2023 		ext4_warning_inode(inode,
2024 		   "page %lu does not have buffers attached", page->index);
2025 		ClearPageDirty(page);
2026 		unlock_page(page);
2027 		return 0;
2028 	}
2029 
2030 	page_bufs = page_buffers(page);
2031 	/*
2032 	 * We cannot do block allocation or other extent handling in this
2033 	 * function. If there are buffers needing that, we have to redirty
2034 	 * the page. But we may reach here when we do a journal commit via
2035 	 * journal_submit_inode_data_buffers() and in that case we must write
2036 	 * allocated buffers to achieve data=ordered mode guarantees.
2037 	 *
2038 	 * Also, if there is only one buffer per page (the fs block
2039 	 * size == the page size), if one buffer needs block
2040 	 * allocation or needs to modify the extent tree to clear the
2041 	 * unwritten flag, we know that the page can't be written at
2042 	 * all, so we might as well refuse the write immediately.
2043 	 * Unfortunately if the block size != page size, we can't as
2044 	 * easily detect this case using ext4_walk_page_buffers(), but
2045 	 * for the extremely common case, this is an optimization that
2046 	 * skips a useless round trip through ext4_bio_write_page().
2047 	 */
2048 	if (ext4_walk_page_buffers(NULL, inode, page_bufs, 0, len, NULL,
2049 				   ext4_bh_delay_or_unwritten)) {
2050 		redirty_page_for_writepage(wbc, page);
2051 		if ((current->flags & PF_MEMALLOC) ||
2052 		    (inode->i_sb->s_blocksize == PAGE_SIZE)) {
2053 			/*
2054 			 * For memory cleaning there's no point in writing only
2055 			 * some buffers. So just bail out. Warn if we came here
2056 			 * from direct reclaim.
2057 			 */
2058 			WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD))
2059 							== PF_MEMALLOC);
2060 			unlock_page(page);
2061 			return 0;
2062 		}
2063 		keep_towrite = true;
2064 	}
2065 
2066 	if (PageChecked(page) && ext4_should_journal_data(inode))
2067 		/*
2068 		 * It's mmapped pagecache.  Add buffers and journal it.  There
2069 		 * doesn't seem much point in redirtying the page here.
2070 		 */
2071 		return __ext4_journalled_writepage(page, len);
2072 
2073 	ext4_io_submit_init(&io_submit, wbc);
2074 	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
2075 	if (!io_submit.io_end) {
2076 		redirty_page_for_writepage(wbc, page);
2077 		unlock_page(page);
2078 		return -ENOMEM;
2079 	}
2080 	ret = ext4_bio_write_page(&io_submit, page, len, keep_towrite);
2081 	ext4_io_submit(&io_submit);
2082 	/* Drop io_end reference we got from init */
2083 	ext4_put_io_end_defer(io_submit.io_end);
2084 	return ret;
2085 }
2086 
2087 static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page)
2088 {
2089 	int len;
2090 	loff_t size;
2091 	int err;
2092 
2093 	BUG_ON(page->index != mpd->first_page);
2094 	clear_page_dirty_for_io(page);
2095 	/*
2096 	 * We have to be very careful here!  Nothing protects writeback path
2097 	 * against i_size changes and the page can be writeably mapped into
2098 	 * page tables. So an application can be growing i_size and writing
2099 	 * data through mmap while writeback runs. clear_page_dirty_for_io()
2100 	 * write-protects our page in page tables and the page cannot get
2101 	 * written to again until we release page lock. So only after
2102 	 * clear_page_dirty_for_io() we are safe to sample i_size for
2103 	 * ext4_bio_write_page() to zero-out tail of the written page. We rely
2104 	 * on the barrier provided by TestClearPageDirty in
2105 	 * clear_page_dirty_for_io() to make sure i_size is really sampled only
2106 	 * after page tables are updated.
2107 	 */
2108 	size = i_size_read(mpd->inode);
2109 	if (page->index == size >> PAGE_SHIFT &&
2110 	    !ext4_verity_in_progress(mpd->inode))
2111 		len = size & ~PAGE_MASK;
2112 	else
2113 		len = PAGE_SIZE;
2114 	err = ext4_bio_write_page(&mpd->io_submit, page, len, false);
2115 	if (!err)
2116 		mpd->wbc->nr_to_write--;
2117 	mpd->first_page++;
2118 
2119 	return err;
2120 }
2121 
2122 #define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
2123 
2124 /*
2125  * mballoc gives us at most this number of blocks...
2126  * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
2127  * The rest of mballoc seems to handle chunks up to full group size.
2128  */
2129 #define MAX_WRITEPAGES_EXTENT_LEN 2048
2130 
2131 /*
2132  * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
2133  *
2134  * @mpd - extent of blocks
2135  * @lblk - logical number of the block in the file
2136  * @bh - buffer head we want to add to the extent
2137  *
2138  * The function is used to collect contig. blocks in the same state. If the
2139  * buffer doesn't require mapping for writeback and we haven't started the
2140  * extent of buffers to map yet, the function returns 'true' immediately - the
2141  * caller can write the buffer right away. Otherwise the function returns true
2142  * if the block has been added to the extent, false if the block couldn't be
2143  * added.
2144  */
2145 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
2146 				   struct buffer_head *bh)
2147 {
2148 	struct ext4_map_blocks *map = &mpd->map;
2149 
2150 	/* Buffer that doesn't need mapping for writeback? */
2151 	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
2152 	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
2153 		/* So far no extent to map => we write the buffer right away */
2154 		if (map->m_len == 0)
2155 			return true;
2156 		return false;
2157 	}
2158 
2159 	/* First block in the extent? */
2160 	if (map->m_len == 0) {
2161 		/* We cannot map unless handle is started... */
2162 		if (!mpd->do_map)
2163 			return false;
2164 		map->m_lblk = lblk;
2165 		map->m_len = 1;
2166 		map->m_flags = bh->b_state & BH_FLAGS;
2167 		return true;
2168 	}
2169 
2170 	/* Don't go larger than mballoc is willing to allocate */
2171 	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
2172 		return false;
2173 
2174 	/* Can we merge the block to our big extent? */
2175 	if (lblk == map->m_lblk + map->m_len &&
2176 	    (bh->b_state & BH_FLAGS) == map->m_flags) {
2177 		map->m_len++;
2178 		return true;
2179 	}
2180 	return false;
2181 }
2182 
2183 /*
2184  * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2185  *
2186  * @mpd - extent of blocks for mapping
2187  * @head - the first buffer in the page
2188  * @bh - buffer we should start processing from
2189  * @lblk - logical number of the block in the file corresponding to @bh
2190  *
2191  * Walk through page buffers from @bh upto @head (exclusive) and either submit
2192  * the page for IO if all buffers in this page were mapped and there's no
2193  * accumulated extent of buffers to map or add buffers in the page to the
2194  * extent of buffers to map. The function returns 1 if the caller can continue
2195  * by processing the next page, 0 if it should stop adding buffers to the
2196  * extent to map because we cannot extend it anymore. It can also return value
2197  * < 0 in case of error during IO submission.
2198  */
2199 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2200 				   struct buffer_head *head,
2201 				   struct buffer_head *bh,
2202 				   ext4_lblk_t lblk)
2203 {
2204 	struct inode *inode = mpd->inode;
2205 	int err;
2206 	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2207 							>> inode->i_blkbits;
2208 
2209 	if (ext4_verity_in_progress(inode))
2210 		blocks = EXT_MAX_BLOCKS;
2211 
2212 	do {
2213 		BUG_ON(buffer_locked(bh));
2214 
2215 		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2216 			/* Found extent to map? */
2217 			if (mpd->map.m_len)
2218 				return 0;
2219 			/* Buffer needs mapping and handle is not started? */
2220 			if (!mpd->do_map)
2221 				return 0;
2222 			/* Everything mapped so far and we hit EOF */
2223 			break;
2224 		}
2225 	} while (lblk++, (bh = bh->b_this_page) != head);
2226 	/* So far everything mapped? Submit the page for IO. */
2227 	if (mpd->map.m_len == 0) {
2228 		err = mpage_submit_page(mpd, head->b_page);
2229 		if (err < 0)
2230 			return err;
2231 	}
2232 	if (lblk >= blocks) {
2233 		mpd->scanned_until_end = 1;
2234 		return 0;
2235 	}
2236 	return 1;
2237 }
2238 
2239 /*
2240  * mpage_process_page - update page buffers corresponding to changed extent and
2241  *		       may submit fully mapped page for IO
2242  *
2243  * @mpd		- description of extent to map, on return next extent to map
2244  * @m_lblk	- logical block mapping.
2245  * @m_pblk	- corresponding physical mapping.
2246  * @map_bh	- determines on return whether this page requires any further
2247  *		  mapping or not.
2248  * Scan given page buffers corresponding to changed extent and update buffer
2249  * state according to new extent state.
2250  * We map delalloc buffers to their physical location, clear unwritten bits.
2251  * If the given page is not fully mapped, we update @map to the next extent in
2252  * the given page that needs mapping & return @map_bh as true.
2253  */
2254 static int mpage_process_page(struct mpage_da_data *mpd, struct page *page,
2255 			      ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2256 			      bool *map_bh)
2257 {
2258 	struct buffer_head *head, *bh;
2259 	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2260 	ext4_lblk_t lblk = *m_lblk;
2261 	ext4_fsblk_t pblock = *m_pblk;
2262 	int err = 0;
2263 	int blkbits = mpd->inode->i_blkbits;
2264 	ssize_t io_end_size = 0;
2265 	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2266 
2267 	bh = head = page_buffers(page);
2268 	do {
2269 		if (lblk < mpd->map.m_lblk)
2270 			continue;
2271 		if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2272 			/*
2273 			 * Buffer after end of mapped extent.
2274 			 * Find next buffer in the page to map.
2275 			 */
2276 			mpd->map.m_len = 0;
2277 			mpd->map.m_flags = 0;
2278 			io_end_vec->size += io_end_size;
2279 
2280 			err = mpage_process_page_bufs(mpd, head, bh, lblk);
2281 			if (err > 0)
2282 				err = 0;
2283 			if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2284 				io_end_vec = ext4_alloc_io_end_vec(io_end);
2285 				if (IS_ERR(io_end_vec)) {
2286 					err = PTR_ERR(io_end_vec);
2287 					goto out;
2288 				}
2289 				io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2290 			}
2291 			*map_bh = true;
2292 			goto out;
2293 		}
2294 		if (buffer_delay(bh)) {
2295 			clear_buffer_delay(bh);
2296 			bh->b_blocknr = pblock++;
2297 		}
2298 		clear_buffer_unwritten(bh);
2299 		io_end_size += (1 << blkbits);
2300 	} while (lblk++, (bh = bh->b_this_page) != head);
2301 
2302 	io_end_vec->size += io_end_size;
2303 	*map_bh = false;
2304 out:
2305 	*m_lblk = lblk;
2306 	*m_pblk = pblock;
2307 	return err;
2308 }
2309 
2310 /*
2311  * mpage_map_buffers - update buffers corresponding to changed extent and
2312  *		       submit fully mapped pages for IO
2313  *
2314  * @mpd - description of extent to map, on return next extent to map
2315  *
2316  * Scan buffers corresponding to changed extent (we expect corresponding pages
2317  * to be already locked) and update buffer state according to new extent state.
2318  * We map delalloc buffers to their physical location, clear unwritten bits,
2319  * and mark buffers as uninit when we perform writes to unwritten extents
2320  * and do extent conversion after IO is finished. If the last page is not fully
2321  * mapped, we update @map to the next extent in the last page that needs
2322  * mapping. Otherwise we submit the page for IO.
2323  */
2324 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2325 {
2326 	struct folio_batch fbatch;
2327 	unsigned nr, i;
2328 	struct inode *inode = mpd->inode;
2329 	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2330 	pgoff_t start, end;
2331 	ext4_lblk_t lblk;
2332 	ext4_fsblk_t pblock;
2333 	int err;
2334 	bool map_bh = false;
2335 
2336 	start = mpd->map.m_lblk >> bpp_bits;
2337 	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2338 	lblk = start << bpp_bits;
2339 	pblock = mpd->map.m_pblk;
2340 
2341 	folio_batch_init(&fbatch);
2342 	while (start <= end) {
2343 		nr = filemap_get_folios(inode->i_mapping, &start, end, &fbatch);
2344 		if (nr == 0)
2345 			break;
2346 		for (i = 0; i < nr; i++) {
2347 			struct page *page = &fbatch.folios[i]->page;
2348 
2349 			err = mpage_process_page(mpd, page, &lblk, &pblock,
2350 						 &map_bh);
2351 			/*
2352 			 * If map_bh is true, means page may require further bh
2353 			 * mapping, or maybe the page was submitted for IO.
2354 			 * So we return to call further extent mapping.
2355 			 */
2356 			if (err < 0 || map_bh)
2357 				goto out;
2358 			/* Page fully mapped - let IO run! */
2359 			err = mpage_submit_page(mpd, page);
2360 			if (err < 0)
2361 				goto out;
2362 		}
2363 		folio_batch_release(&fbatch);
2364 	}
2365 	/* Extent fully mapped and matches with page boundary. We are done. */
2366 	mpd->map.m_len = 0;
2367 	mpd->map.m_flags = 0;
2368 	return 0;
2369 out:
2370 	folio_batch_release(&fbatch);
2371 	return err;
2372 }
2373 
2374 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2375 {
2376 	struct inode *inode = mpd->inode;
2377 	struct ext4_map_blocks *map = &mpd->map;
2378 	int get_blocks_flags;
2379 	int err, dioread_nolock;
2380 
2381 	trace_ext4_da_write_pages_extent(inode, map);
2382 	/*
2383 	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2384 	 * to convert an unwritten extent to be initialized (in the case
2385 	 * where we have written into one or more preallocated blocks).  It is
2386 	 * possible that we're going to need more metadata blocks than
2387 	 * previously reserved. However we must not fail because we're in
2388 	 * writeback and there is nothing we can do about it so it might result
2389 	 * in data loss.  So use reserved blocks to allocate metadata if
2390 	 * possible.
2391 	 *
2392 	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2393 	 * the blocks in question are delalloc blocks.  This indicates
2394 	 * that the blocks and quotas has already been checked when
2395 	 * the data was copied into the page cache.
2396 	 */
2397 	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2398 			   EXT4_GET_BLOCKS_METADATA_NOFAIL |
2399 			   EXT4_GET_BLOCKS_IO_SUBMIT;
2400 	dioread_nolock = ext4_should_dioread_nolock(inode);
2401 	if (dioread_nolock)
2402 		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2403 	if (map->m_flags & BIT(BH_Delay))
2404 		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2405 
2406 	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2407 	if (err < 0)
2408 		return err;
2409 	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2410 		if (!mpd->io_submit.io_end->handle &&
2411 		    ext4_handle_valid(handle)) {
2412 			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2413 			handle->h_rsv_handle = NULL;
2414 		}
2415 		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2416 	}
2417 
2418 	BUG_ON(map->m_len == 0);
2419 	return 0;
2420 }
2421 
2422 /*
2423  * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2424  *				 mpd->len and submit pages underlying it for IO
2425  *
2426  * @handle - handle for journal operations
2427  * @mpd - extent to map
2428  * @give_up_on_write - we set this to true iff there is a fatal error and there
2429  *                     is no hope of writing the data. The caller should discard
2430  *                     dirty pages to avoid infinite loops.
2431  *
2432  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2433  * delayed, blocks are allocated, if it is unwritten, we may need to convert
2434  * them to initialized or split the described range from larger unwritten
2435  * extent. Note that we need not map all the described range since allocation
2436  * can return less blocks or the range is covered by more unwritten extents. We
2437  * cannot map more because we are limited by reserved transaction credits. On
2438  * the other hand we always make sure that the last touched page is fully
2439  * mapped so that it can be written out (and thus forward progress is
2440  * guaranteed). After mapping we submit all mapped pages for IO.
2441  */
2442 static int mpage_map_and_submit_extent(handle_t *handle,
2443 				       struct mpage_da_data *mpd,
2444 				       bool *give_up_on_write)
2445 {
2446 	struct inode *inode = mpd->inode;
2447 	struct ext4_map_blocks *map = &mpd->map;
2448 	int err;
2449 	loff_t disksize;
2450 	int progress = 0;
2451 	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2452 	struct ext4_io_end_vec *io_end_vec;
2453 
2454 	io_end_vec = ext4_alloc_io_end_vec(io_end);
2455 	if (IS_ERR(io_end_vec))
2456 		return PTR_ERR(io_end_vec);
2457 	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2458 	do {
2459 		err = mpage_map_one_extent(handle, mpd);
2460 		if (err < 0) {
2461 			struct super_block *sb = inode->i_sb;
2462 
2463 			if (ext4_forced_shutdown(EXT4_SB(sb)) ||
2464 			    ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
2465 				goto invalidate_dirty_pages;
2466 			/*
2467 			 * Let the uper layers retry transient errors.
2468 			 * In the case of ENOSPC, if ext4_count_free_blocks()
2469 			 * is non-zero, a commit should free up blocks.
2470 			 */
2471 			if ((err == -ENOMEM) ||
2472 			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2473 				if (progress)
2474 					goto update_disksize;
2475 				return err;
2476 			}
2477 			ext4_msg(sb, KERN_CRIT,
2478 				 "Delayed block allocation failed for "
2479 				 "inode %lu at logical offset %llu with"
2480 				 " max blocks %u with error %d",
2481 				 inode->i_ino,
2482 				 (unsigned long long)map->m_lblk,
2483 				 (unsigned)map->m_len, -err);
2484 			ext4_msg(sb, KERN_CRIT,
2485 				 "This should not happen!! Data will "
2486 				 "be lost\n");
2487 			if (err == -ENOSPC)
2488 				ext4_print_free_blocks(inode);
2489 		invalidate_dirty_pages:
2490 			*give_up_on_write = true;
2491 			return err;
2492 		}
2493 		progress = 1;
2494 		/*
2495 		 * Update buffer state, submit mapped pages, and get us new
2496 		 * extent to map
2497 		 */
2498 		err = mpage_map_and_submit_buffers(mpd);
2499 		if (err < 0)
2500 			goto update_disksize;
2501 	} while (map->m_len);
2502 
2503 update_disksize:
2504 	/*
2505 	 * Update on-disk size after IO is submitted.  Races with
2506 	 * truncate are avoided by checking i_size under i_data_sem.
2507 	 */
2508 	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2509 	if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2510 		int err2;
2511 		loff_t i_size;
2512 
2513 		down_write(&EXT4_I(inode)->i_data_sem);
2514 		i_size = i_size_read(inode);
2515 		if (disksize > i_size)
2516 			disksize = i_size;
2517 		if (disksize > EXT4_I(inode)->i_disksize)
2518 			EXT4_I(inode)->i_disksize = disksize;
2519 		up_write(&EXT4_I(inode)->i_data_sem);
2520 		err2 = ext4_mark_inode_dirty(handle, inode);
2521 		if (err2) {
2522 			ext4_error_err(inode->i_sb, -err2,
2523 				       "Failed to mark inode %lu dirty",
2524 				       inode->i_ino);
2525 		}
2526 		if (!err)
2527 			err = err2;
2528 	}
2529 	return err;
2530 }
2531 
2532 /*
2533  * Calculate the total number of credits to reserve for one writepages
2534  * iteration. This is called from ext4_writepages(). We map an extent of
2535  * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2536  * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2537  * bpp - 1 blocks in bpp different extents.
2538  */
2539 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2540 {
2541 	int bpp = ext4_journal_blocks_per_page(inode);
2542 
2543 	return ext4_meta_trans_blocks(inode,
2544 				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2545 }
2546 
2547 /*
2548  * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2549  * 				 and underlying extent to map
2550  *
2551  * @mpd - where to look for pages
2552  *
2553  * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2554  * IO immediately. When we find a page which isn't mapped we start accumulating
2555  * extent of buffers underlying these pages that needs mapping (formed by
2556  * either delayed or unwritten buffers). We also lock the pages containing
2557  * these buffers. The extent found is returned in @mpd structure (starting at
2558  * mpd->lblk with length mpd->len blocks).
2559  *
2560  * Note that this function can attach bios to one io_end structure which are
2561  * neither logically nor physically contiguous. Although it may seem as an
2562  * unnecessary complication, it is actually inevitable in blocksize < pagesize
2563  * case as we need to track IO to all buffers underlying a page in one io_end.
2564  */
2565 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2566 {
2567 	struct address_space *mapping = mpd->inode->i_mapping;
2568 	struct pagevec pvec;
2569 	unsigned int nr_pages;
2570 	long left = mpd->wbc->nr_to_write;
2571 	pgoff_t index = mpd->first_page;
2572 	pgoff_t end = mpd->last_page;
2573 	xa_mark_t tag;
2574 	int i, err = 0;
2575 	int blkbits = mpd->inode->i_blkbits;
2576 	ext4_lblk_t lblk;
2577 	struct buffer_head *head;
2578 
2579 	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2580 		tag = PAGECACHE_TAG_TOWRITE;
2581 	else
2582 		tag = PAGECACHE_TAG_DIRTY;
2583 
2584 	pagevec_init(&pvec);
2585 	mpd->map.m_len = 0;
2586 	mpd->next_page = index;
2587 	while (index <= end) {
2588 		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
2589 				tag);
2590 		if (nr_pages == 0)
2591 			break;
2592 
2593 		for (i = 0; i < nr_pages; i++) {
2594 			struct page *page = pvec.pages[i];
2595 
2596 			/*
2597 			 * Accumulated enough dirty pages? This doesn't apply
2598 			 * to WB_SYNC_ALL mode. For integrity sync we have to
2599 			 * keep going because someone may be concurrently
2600 			 * dirtying pages, and we might have synced a lot of
2601 			 * newly appeared dirty pages, but have not synced all
2602 			 * of the old dirty pages.
2603 			 */
2604 			if (mpd->wbc->sync_mode == WB_SYNC_NONE && left <= 0)
2605 				goto out;
2606 
2607 			/* If we can't merge this page, we are done. */
2608 			if (mpd->map.m_len > 0 && mpd->next_page != page->index)
2609 				goto out;
2610 
2611 			lock_page(page);
2612 			/*
2613 			 * If the page is no longer dirty, or its mapping no
2614 			 * longer corresponds to inode we are writing (which
2615 			 * means it has been truncated or invalidated), or the
2616 			 * page is already under writeback and we are not doing
2617 			 * a data integrity writeback, skip the page
2618 			 */
2619 			if (!PageDirty(page) ||
2620 			    (PageWriteback(page) &&
2621 			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2622 			    unlikely(page->mapping != mapping)) {
2623 				unlock_page(page);
2624 				continue;
2625 			}
2626 
2627 			wait_on_page_writeback(page);
2628 			BUG_ON(PageWriteback(page));
2629 
2630 			/*
2631 			 * Should never happen but for buggy code in
2632 			 * other subsystems that call
2633 			 * set_page_dirty() without properly warning
2634 			 * the file system first.  See [1] for more
2635 			 * information.
2636 			 *
2637 			 * [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
2638 			 */
2639 			if (!page_has_buffers(page)) {
2640 				ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", page->index);
2641 				ClearPageDirty(page);
2642 				unlock_page(page);
2643 				continue;
2644 			}
2645 
2646 			if (mpd->map.m_len == 0)
2647 				mpd->first_page = page->index;
2648 			mpd->next_page = page->index + 1;
2649 			/* Add all dirty buffers to mpd */
2650 			lblk = ((ext4_lblk_t)page->index) <<
2651 				(PAGE_SHIFT - blkbits);
2652 			head = page_buffers(page);
2653 			err = mpage_process_page_bufs(mpd, head, head, lblk);
2654 			if (err <= 0)
2655 				goto out;
2656 			err = 0;
2657 			left--;
2658 		}
2659 		pagevec_release(&pvec);
2660 		cond_resched();
2661 	}
2662 	mpd->scanned_until_end = 1;
2663 	return 0;
2664 out:
2665 	pagevec_release(&pvec);
2666 	return err;
2667 }
2668 
2669 static int ext4_writepages(struct address_space *mapping,
2670 			   struct writeback_control *wbc)
2671 {
2672 	pgoff_t	writeback_index = 0;
2673 	long nr_to_write = wbc->nr_to_write;
2674 	int range_whole = 0;
2675 	int cycled = 1;
2676 	handle_t *handle = NULL;
2677 	struct mpage_da_data mpd;
2678 	struct inode *inode = mapping->host;
2679 	int needed_blocks, rsv_blocks = 0, ret = 0;
2680 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2681 	struct blk_plug plug;
2682 	bool give_up_on_write = false;
2683 
2684 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2685 		return -EIO;
2686 
2687 	percpu_down_read(&sbi->s_writepages_rwsem);
2688 	trace_ext4_writepages(inode, wbc);
2689 
2690 	/*
2691 	 * No pages to write? This is mainly a kludge to avoid starting
2692 	 * a transaction for special inodes like journal inode on last iput()
2693 	 * because that could violate lock ordering on umount
2694 	 */
2695 	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2696 		goto out_writepages;
2697 
2698 	if (ext4_should_journal_data(inode)) {
2699 		ret = generic_writepages(mapping, wbc);
2700 		goto out_writepages;
2701 	}
2702 
2703 	/*
2704 	 * If the filesystem has aborted, it is read-only, so return
2705 	 * right away instead of dumping stack traces later on that
2706 	 * will obscure the real source of the problem.  We test
2707 	 * EXT4_MF_FS_ABORTED instead of sb->s_flag's SB_RDONLY because
2708 	 * the latter could be true if the filesystem is mounted
2709 	 * read-only, and in that case, ext4_writepages should
2710 	 * *never* be called, so if that ever happens, we would want
2711 	 * the stack trace.
2712 	 */
2713 	if (unlikely(ext4_forced_shutdown(EXT4_SB(mapping->host->i_sb)) ||
2714 		     ext4_test_mount_flag(inode->i_sb, EXT4_MF_FS_ABORTED))) {
2715 		ret = -EROFS;
2716 		goto out_writepages;
2717 	}
2718 
2719 	/*
2720 	 * If we have inline data and arrive here, it means that
2721 	 * we will soon create the block for the 1st page, so
2722 	 * we'd better clear the inline data here.
2723 	 */
2724 	if (ext4_has_inline_data(inode)) {
2725 		/* Just inode will be modified... */
2726 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2727 		if (IS_ERR(handle)) {
2728 			ret = PTR_ERR(handle);
2729 			goto out_writepages;
2730 		}
2731 		BUG_ON(ext4_test_inode_state(inode,
2732 				EXT4_STATE_MAY_INLINE_DATA));
2733 		ext4_destroy_inline_data(handle, inode);
2734 		ext4_journal_stop(handle);
2735 	}
2736 
2737 	if (ext4_should_dioread_nolock(inode)) {
2738 		/*
2739 		 * We may need to convert up to one extent per block in
2740 		 * the page and we may dirty the inode.
2741 		 */
2742 		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2743 						PAGE_SIZE >> inode->i_blkbits);
2744 	}
2745 
2746 	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2747 		range_whole = 1;
2748 
2749 	if (wbc->range_cyclic) {
2750 		writeback_index = mapping->writeback_index;
2751 		if (writeback_index)
2752 			cycled = 0;
2753 		mpd.first_page = writeback_index;
2754 		mpd.last_page = -1;
2755 	} else {
2756 		mpd.first_page = wbc->range_start >> PAGE_SHIFT;
2757 		mpd.last_page = wbc->range_end >> PAGE_SHIFT;
2758 	}
2759 
2760 	mpd.inode = inode;
2761 	mpd.wbc = wbc;
2762 	ext4_io_submit_init(&mpd.io_submit, wbc);
2763 retry:
2764 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2765 		tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
2766 	blk_start_plug(&plug);
2767 
2768 	/*
2769 	 * First writeback pages that don't need mapping - we can avoid
2770 	 * starting a transaction unnecessarily and also avoid being blocked
2771 	 * in the block layer on device congestion while having transaction
2772 	 * started.
2773 	 */
2774 	mpd.do_map = 0;
2775 	mpd.scanned_until_end = 0;
2776 	mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2777 	if (!mpd.io_submit.io_end) {
2778 		ret = -ENOMEM;
2779 		goto unplug;
2780 	}
2781 	ret = mpage_prepare_extent_to_map(&mpd);
2782 	/* Unlock pages we didn't use */
2783 	mpage_release_unused_pages(&mpd, false);
2784 	/* Submit prepared bio */
2785 	ext4_io_submit(&mpd.io_submit);
2786 	ext4_put_io_end_defer(mpd.io_submit.io_end);
2787 	mpd.io_submit.io_end = NULL;
2788 	if (ret < 0)
2789 		goto unplug;
2790 
2791 	while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
2792 		/* For each extent of pages we use new io_end */
2793 		mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2794 		if (!mpd.io_submit.io_end) {
2795 			ret = -ENOMEM;
2796 			break;
2797 		}
2798 
2799 		/*
2800 		 * We have two constraints: We find one extent to map and we
2801 		 * must always write out whole page (makes a difference when
2802 		 * blocksize < pagesize) so that we don't block on IO when we
2803 		 * try to write out the rest of the page. Journalled mode is
2804 		 * not supported by delalloc.
2805 		 */
2806 		BUG_ON(ext4_should_journal_data(inode));
2807 		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2808 
2809 		/* start a new transaction */
2810 		handle = ext4_journal_start_with_reserve(inode,
2811 				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2812 		if (IS_ERR(handle)) {
2813 			ret = PTR_ERR(handle);
2814 			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2815 			       "%ld pages, ino %lu; err %d", __func__,
2816 				wbc->nr_to_write, inode->i_ino, ret);
2817 			/* Release allocated io_end */
2818 			ext4_put_io_end(mpd.io_submit.io_end);
2819 			mpd.io_submit.io_end = NULL;
2820 			break;
2821 		}
2822 		mpd.do_map = 1;
2823 
2824 		trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
2825 		ret = mpage_prepare_extent_to_map(&mpd);
2826 		if (!ret && mpd.map.m_len)
2827 			ret = mpage_map_and_submit_extent(handle, &mpd,
2828 					&give_up_on_write);
2829 		/*
2830 		 * Caution: If the handle is synchronous,
2831 		 * ext4_journal_stop() can wait for transaction commit
2832 		 * to finish which may depend on writeback of pages to
2833 		 * complete or on page lock to be released.  In that
2834 		 * case, we have to wait until after we have
2835 		 * submitted all the IO, released page locks we hold,
2836 		 * and dropped io_end reference (for extent conversion
2837 		 * to be able to complete) before stopping the handle.
2838 		 */
2839 		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2840 			ext4_journal_stop(handle);
2841 			handle = NULL;
2842 			mpd.do_map = 0;
2843 		}
2844 		/* Unlock pages we didn't use */
2845 		mpage_release_unused_pages(&mpd, give_up_on_write);
2846 		/* Submit prepared bio */
2847 		ext4_io_submit(&mpd.io_submit);
2848 
2849 		/*
2850 		 * Drop our io_end reference we got from init. We have
2851 		 * to be careful and use deferred io_end finishing if
2852 		 * we are still holding the transaction as we can
2853 		 * release the last reference to io_end which may end
2854 		 * up doing unwritten extent conversion.
2855 		 */
2856 		if (handle) {
2857 			ext4_put_io_end_defer(mpd.io_submit.io_end);
2858 			ext4_journal_stop(handle);
2859 		} else
2860 			ext4_put_io_end(mpd.io_submit.io_end);
2861 		mpd.io_submit.io_end = NULL;
2862 
2863 		if (ret == -ENOSPC && sbi->s_journal) {
2864 			/*
2865 			 * Commit the transaction which would
2866 			 * free blocks released in the transaction
2867 			 * and try again
2868 			 */
2869 			jbd2_journal_force_commit_nested(sbi->s_journal);
2870 			ret = 0;
2871 			continue;
2872 		}
2873 		/* Fatal error - ENOMEM, EIO... */
2874 		if (ret)
2875 			break;
2876 	}
2877 unplug:
2878 	blk_finish_plug(&plug);
2879 	if (!ret && !cycled && wbc->nr_to_write > 0) {
2880 		cycled = 1;
2881 		mpd.last_page = writeback_index - 1;
2882 		mpd.first_page = 0;
2883 		goto retry;
2884 	}
2885 
2886 	/* Update index */
2887 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2888 		/*
2889 		 * Set the writeback_index so that range_cyclic
2890 		 * mode will write it back later
2891 		 */
2892 		mapping->writeback_index = mpd.first_page;
2893 
2894 out_writepages:
2895 	trace_ext4_writepages_result(inode, wbc, ret,
2896 				     nr_to_write - wbc->nr_to_write);
2897 	percpu_up_read(&sbi->s_writepages_rwsem);
2898 	return ret;
2899 }
2900 
2901 static int ext4_dax_writepages(struct address_space *mapping,
2902 			       struct writeback_control *wbc)
2903 {
2904 	int ret;
2905 	long nr_to_write = wbc->nr_to_write;
2906 	struct inode *inode = mapping->host;
2907 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2908 
2909 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2910 		return -EIO;
2911 
2912 	percpu_down_read(&sbi->s_writepages_rwsem);
2913 	trace_ext4_writepages(inode, wbc);
2914 
2915 	ret = dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
2916 	trace_ext4_writepages_result(inode, wbc, ret,
2917 				     nr_to_write - wbc->nr_to_write);
2918 	percpu_up_read(&sbi->s_writepages_rwsem);
2919 	return ret;
2920 }
2921 
2922 static int ext4_nonda_switch(struct super_block *sb)
2923 {
2924 	s64 free_clusters, dirty_clusters;
2925 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2926 
2927 	/*
2928 	 * switch to non delalloc mode if we are running low
2929 	 * on free block. The free block accounting via percpu
2930 	 * counters can get slightly wrong with percpu_counter_batch getting
2931 	 * accumulated on each CPU without updating global counters
2932 	 * Delalloc need an accurate free block accounting. So switch
2933 	 * to non delalloc when we are near to error range.
2934 	 */
2935 	free_clusters =
2936 		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2937 	dirty_clusters =
2938 		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2939 	/*
2940 	 * Start pushing delalloc when 1/2 of free blocks are dirty.
2941 	 */
2942 	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2943 		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2944 
2945 	if (2 * free_clusters < 3 * dirty_clusters ||
2946 	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2947 		/*
2948 		 * free block count is less than 150% of dirty blocks
2949 		 * or free blocks is less than watermark
2950 		 */
2951 		return 1;
2952 	}
2953 	return 0;
2954 }
2955 
2956 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2957 			       loff_t pos, unsigned len,
2958 			       struct page **pagep, void **fsdata)
2959 {
2960 	int ret, retries = 0;
2961 	struct page *page;
2962 	pgoff_t index;
2963 	struct inode *inode = mapping->host;
2964 
2965 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
2966 		return -EIO;
2967 
2968 	index = pos >> PAGE_SHIFT;
2969 
2970 	if (ext4_nonda_switch(inode->i_sb) || ext4_verity_in_progress(inode)) {
2971 		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2972 		return ext4_write_begin(file, mapping, pos,
2973 					len, pagep, fsdata);
2974 	}
2975 	*fsdata = (void *)0;
2976 	trace_ext4_da_write_begin(inode, pos, len);
2977 
2978 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2979 		ret = ext4_da_write_inline_data_begin(mapping, inode, pos, len,
2980 						      pagep, fsdata);
2981 		if (ret < 0)
2982 			return ret;
2983 		if (ret == 1)
2984 			return 0;
2985 	}
2986 
2987 retry:
2988 	page = grab_cache_page_write_begin(mapping, index);
2989 	if (!page)
2990 		return -ENOMEM;
2991 
2992 	/* In case writeback began while the page was unlocked */
2993 	wait_for_stable_page(page);
2994 
2995 #ifdef CONFIG_FS_ENCRYPTION
2996 	ret = ext4_block_write_begin(page, pos, len,
2997 				     ext4_da_get_block_prep);
2998 #else
2999 	ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep);
3000 #endif
3001 	if (ret < 0) {
3002 		unlock_page(page);
3003 		put_page(page);
3004 		/*
3005 		 * block_write_begin may have instantiated a few blocks
3006 		 * outside i_size.  Trim these off again. Don't need
3007 		 * i_size_read because we hold inode lock.
3008 		 */
3009 		if (pos + len > inode->i_size)
3010 			ext4_truncate_failed_write(inode);
3011 
3012 		if (ret == -ENOSPC &&
3013 		    ext4_should_retry_alloc(inode->i_sb, &retries))
3014 			goto retry;
3015 		return ret;
3016 	}
3017 
3018 	*pagep = page;
3019 	return ret;
3020 }
3021 
3022 /*
3023  * Check if we should update i_disksize
3024  * when write to the end of file but not require block allocation
3025  */
3026 static int ext4_da_should_update_i_disksize(struct page *page,
3027 					    unsigned long offset)
3028 {
3029 	struct buffer_head *bh;
3030 	struct inode *inode = page->mapping->host;
3031 	unsigned int idx;
3032 	int i;
3033 
3034 	bh = page_buffers(page);
3035 	idx = offset >> inode->i_blkbits;
3036 
3037 	for (i = 0; i < idx; i++)
3038 		bh = bh->b_this_page;
3039 
3040 	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3041 		return 0;
3042 	return 1;
3043 }
3044 
3045 static int ext4_da_write_end(struct file *file,
3046 			     struct address_space *mapping,
3047 			     loff_t pos, unsigned len, unsigned copied,
3048 			     struct page *page, void *fsdata)
3049 {
3050 	struct inode *inode = mapping->host;
3051 	loff_t new_i_size;
3052 	unsigned long start, end;
3053 	int write_mode = (int)(unsigned long)fsdata;
3054 
3055 	if (write_mode == FALL_BACK_TO_NONDELALLOC)
3056 		return ext4_write_end(file, mapping, pos,
3057 				      len, copied, page, fsdata);
3058 
3059 	trace_ext4_da_write_end(inode, pos, len, copied);
3060 
3061 	if (write_mode != CONVERT_INLINE_DATA &&
3062 	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3063 	    ext4_has_inline_data(inode))
3064 		return ext4_write_inline_data_end(inode, pos, len, copied, page);
3065 
3066 	start = pos & (PAGE_SIZE - 1);
3067 	end = start + copied - 1;
3068 
3069 	/*
3070 	 * Since we are holding inode lock, we are sure i_disksize <=
3071 	 * i_size. We also know that if i_disksize < i_size, there are
3072 	 * delalloc writes pending in the range upto i_size. If the end of
3073 	 * the current write is <= i_size, there's no need to touch
3074 	 * i_disksize since writeback will push i_disksize upto i_size
3075 	 * eventually. If the end of the current write is > i_size and
3076 	 * inside an allocated block (ext4_da_should_update_i_disksize()
3077 	 * check), we need to update i_disksize here as neither
3078 	 * ext4_writepage() nor certain ext4_writepages() paths not
3079 	 * allocating blocks update i_disksize.
3080 	 *
3081 	 * Note that we defer inode dirtying to generic_write_end() /
3082 	 * ext4_da_write_inline_data_end().
3083 	 */
3084 	new_i_size = pos + copied;
3085 	if (copied && new_i_size > inode->i_size &&
3086 	    ext4_da_should_update_i_disksize(page, end))
3087 		ext4_update_i_disksize(inode, new_i_size);
3088 
3089 	return generic_write_end(file, mapping, pos, len, copied, page, fsdata);
3090 }
3091 
3092 /*
3093  * Force all delayed allocation blocks to be allocated for a given inode.
3094  */
3095 int ext4_alloc_da_blocks(struct inode *inode)
3096 {
3097 	trace_ext4_alloc_da_blocks(inode);
3098 
3099 	if (!EXT4_I(inode)->i_reserved_data_blocks)
3100 		return 0;
3101 
3102 	/*
3103 	 * We do something simple for now.  The filemap_flush() will
3104 	 * also start triggering a write of the data blocks, which is
3105 	 * not strictly speaking necessary (and for users of
3106 	 * laptop_mode, not even desirable).  However, to do otherwise
3107 	 * would require replicating code paths in:
3108 	 *
3109 	 * ext4_writepages() ->
3110 	 *    write_cache_pages() ---> (via passed in callback function)
3111 	 *        __mpage_da_writepage() -->
3112 	 *           mpage_add_bh_to_extent()
3113 	 *           mpage_da_map_blocks()
3114 	 *
3115 	 * The problem is that write_cache_pages(), located in
3116 	 * mm/page-writeback.c, marks pages clean in preparation for
3117 	 * doing I/O, which is not desirable if we're not planning on
3118 	 * doing I/O at all.
3119 	 *
3120 	 * We could call write_cache_pages(), and then redirty all of
3121 	 * the pages by calling redirty_page_for_writepage() but that
3122 	 * would be ugly in the extreme.  So instead we would need to
3123 	 * replicate parts of the code in the above functions,
3124 	 * simplifying them because we wouldn't actually intend to
3125 	 * write out the pages, but rather only collect contiguous
3126 	 * logical block extents, call the multi-block allocator, and
3127 	 * then update the buffer heads with the block allocations.
3128 	 *
3129 	 * For now, though, we'll cheat by calling filemap_flush(),
3130 	 * which will map the blocks, and start the I/O, but not
3131 	 * actually wait for the I/O to complete.
3132 	 */
3133 	return filemap_flush(inode->i_mapping);
3134 }
3135 
3136 /*
3137  * bmap() is special.  It gets used by applications such as lilo and by
3138  * the swapper to find the on-disk block of a specific piece of data.
3139  *
3140  * Naturally, this is dangerous if the block concerned is still in the
3141  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3142  * filesystem and enables swap, then they may get a nasty shock when the
3143  * data getting swapped to that swapfile suddenly gets overwritten by
3144  * the original zero's written out previously to the journal and
3145  * awaiting writeback in the kernel's buffer cache.
3146  *
3147  * So, if we see any bmap calls here on a modified, data-journaled file,
3148  * take extra steps to flush any blocks which might be in the cache.
3149  */
3150 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3151 {
3152 	struct inode *inode = mapping->host;
3153 	journal_t *journal;
3154 	sector_t ret = 0;
3155 	int err;
3156 
3157 	inode_lock_shared(inode);
3158 	/*
3159 	 * We can get here for an inline file via the FIBMAP ioctl
3160 	 */
3161 	if (ext4_has_inline_data(inode))
3162 		goto out;
3163 
3164 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3165 			test_opt(inode->i_sb, DELALLOC)) {
3166 		/*
3167 		 * With delalloc we want to sync the file
3168 		 * so that we can make sure we allocate
3169 		 * blocks for file
3170 		 */
3171 		filemap_write_and_wait(mapping);
3172 	}
3173 
3174 	if (EXT4_JOURNAL(inode) &&
3175 	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
3176 		/*
3177 		 * This is a REALLY heavyweight approach, but the use of
3178 		 * bmap on dirty files is expected to be extremely rare:
3179 		 * only if we run lilo or swapon on a freshly made file
3180 		 * do we expect this to happen.
3181 		 *
3182 		 * (bmap requires CAP_SYS_RAWIO so this does not
3183 		 * represent an unprivileged user DOS attack --- we'd be
3184 		 * in trouble if mortal users could trigger this path at
3185 		 * will.)
3186 		 *
3187 		 * NB. EXT4_STATE_JDATA is not set on files other than
3188 		 * regular files.  If somebody wants to bmap a directory
3189 		 * or symlink and gets confused because the buffer
3190 		 * hasn't yet been flushed to disk, they deserve
3191 		 * everything they get.
3192 		 */
3193 
3194 		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
3195 		journal = EXT4_JOURNAL(inode);
3196 		jbd2_journal_lock_updates(journal);
3197 		err = jbd2_journal_flush(journal, 0);
3198 		jbd2_journal_unlock_updates(journal);
3199 
3200 		if (err)
3201 			goto out;
3202 	}
3203 
3204 	ret = iomap_bmap(mapping, block, &ext4_iomap_ops);
3205 
3206 out:
3207 	inode_unlock_shared(inode);
3208 	return ret;
3209 }
3210 
3211 static int ext4_read_folio(struct file *file, struct folio *folio)
3212 {
3213 	struct page *page = &folio->page;
3214 	int ret = -EAGAIN;
3215 	struct inode *inode = page->mapping->host;
3216 
3217 	trace_ext4_readpage(page);
3218 
3219 	if (ext4_has_inline_data(inode))
3220 		ret = ext4_readpage_inline(inode, page);
3221 
3222 	if (ret == -EAGAIN)
3223 		return ext4_mpage_readpages(inode, NULL, page);
3224 
3225 	return ret;
3226 }
3227 
3228 static void ext4_readahead(struct readahead_control *rac)
3229 {
3230 	struct inode *inode = rac->mapping->host;
3231 
3232 	/* If the file has inline data, no need to do readahead. */
3233 	if (ext4_has_inline_data(inode))
3234 		return;
3235 
3236 	ext4_mpage_readpages(inode, rac, NULL);
3237 }
3238 
3239 static void ext4_invalidate_folio(struct folio *folio, size_t offset,
3240 				size_t length)
3241 {
3242 	trace_ext4_invalidate_folio(folio, offset, length);
3243 
3244 	/* No journalling happens on data buffers when this function is used */
3245 	WARN_ON(folio_buffers(folio) && buffer_jbd(folio_buffers(folio)));
3246 
3247 	block_invalidate_folio(folio, offset, length);
3248 }
3249 
3250 static int __ext4_journalled_invalidate_folio(struct folio *folio,
3251 					    size_t offset, size_t length)
3252 {
3253 	journal_t *journal = EXT4_JOURNAL(folio->mapping->host);
3254 
3255 	trace_ext4_journalled_invalidate_folio(folio, offset, length);
3256 
3257 	/*
3258 	 * If it's a full truncate we just forget about the pending dirtying
3259 	 */
3260 	if (offset == 0 && length == folio_size(folio))
3261 		folio_clear_checked(folio);
3262 
3263 	return jbd2_journal_invalidate_folio(journal, folio, offset, length);
3264 }
3265 
3266 /* Wrapper for aops... */
3267 static void ext4_journalled_invalidate_folio(struct folio *folio,
3268 					   size_t offset,
3269 					   size_t length)
3270 {
3271 	WARN_ON(__ext4_journalled_invalidate_folio(folio, offset, length) < 0);
3272 }
3273 
3274 static bool ext4_release_folio(struct folio *folio, gfp_t wait)
3275 {
3276 	journal_t *journal = EXT4_JOURNAL(folio->mapping->host);
3277 
3278 	trace_ext4_releasepage(&folio->page);
3279 
3280 	/* Page has dirty journalled data -> cannot release */
3281 	if (folio_test_checked(folio))
3282 		return false;
3283 	if (journal)
3284 		return jbd2_journal_try_to_free_buffers(journal, folio);
3285 	else
3286 		return try_to_free_buffers(folio);
3287 }
3288 
3289 static bool ext4_inode_datasync_dirty(struct inode *inode)
3290 {
3291 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3292 
3293 	if (journal) {
3294 		if (jbd2_transaction_committed(journal,
3295 			EXT4_I(inode)->i_datasync_tid))
3296 			return false;
3297 		if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3298 			return !list_empty(&EXT4_I(inode)->i_fc_list);
3299 		return true;
3300 	}
3301 
3302 	/* Any metadata buffers to write? */
3303 	if (!list_empty(&inode->i_mapping->private_list))
3304 		return true;
3305 	return inode->i_state & I_DIRTY_DATASYNC;
3306 }
3307 
3308 static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3309 			   struct ext4_map_blocks *map, loff_t offset,
3310 			   loff_t length, unsigned int flags)
3311 {
3312 	u8 blkbits = inode->i_blkbits;
3313 
3314 	/*
3315 	 * Writes that span EOF might trigger an I/O size update on completion,
3316 	 * so consider them to be dirty for the purpose of O_DSYNC, even if
3317 	 * there is no other metadata changes being made or are pending.
3318 	 */
3319 	iomap->flags = 0;
3320 	if (ext4_inode_datasync_dirty(inode) ||
3321 	    offset + length > i_size_read(inode))
3322 		iomap->flags |= IOMAP_F_DIRTY;
3323 
3324 	if (map->m_flags & EXT4_MAP_NEW)
3325 		iomap->flags |= IOMAP_F_NEW;
3326 
3327 	if (flags & IOMAP_DAX)
3328 		iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
3329 	else
3330 		iomap->bdev = inode->i_sb->s_bdev;
3331 	iomap->offset = (u64) map->m_lblk << blkbits;
3332 	iomap->length = (u64) map->m_len << blkbits;
3333 
3334 	if ((map->m_flags & EXT4_MAP_MAPPED) &&
3335 	    !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3336 		iomap->flags |= IOMAP_F_MERGED;
3337 
3338 	/*
3339 	 * Flags passed to ext4_map_blocks() for direct I/O writes can result
3340 	 * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3341 	 * set. In order for any allocated unwritten extents to be converted
3342 	 * into written extents correctly within the ->end_io() handler, we
3343 	 * need to ensure that the iomap->type is set appropriately. Hence, the
3344 	 * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3345 	 * been set first.
3346 	 */
3347 	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3348 		iomap->type = IOMAP_UNWRITTEN;
3349 		iomap->addr = (u64) map->m_pblk << blkbits;
3350 		if (flags & IOMAP_DAX)
3351 			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
3352 	} else if (map->m_flags & EXT4_MAP_MAPPED) {
3353 		iomap->type = IOMAP_MAPPED;
3354 		iomap->addr = (u64) map->m_pblk << blkbits;
3355 		if (flags & IOMAP_DAX)
3356 			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
3357 	} else {
3358 		iomap->type = IOMAP_HOLE;
3359 		iomap->addr = IOMAP_NULL_ADDR;
3360 	}
3361 }
3362 
3363 static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3364 			    unsigned int flags)
3365 {
3366 	handle_t *handle;
3367 	u8 blkbits = inode->i_blkbits;
3368 	int ret, dio_credits, m_flags = 0, retries = 0;
3369 
3370 	/*
3371 	 * Trim the mapping request to the maximum value that we can map at
3372 	 * once for direct I/O.
3373 	 */
3374 	if (map->m_len > DIO_MAX_BLOCKS)
3375 		map->m_len = DIO_MAX_BLOCKS;
3376 	dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3377 
3378 retry:
3379 	/*
3380 	 * Either we allocate blocks and then don't get an unwritten extent, so
3381 	 * in that case we have reserved enough credits. Or, the blocks are
3382 	 * already allocated and unwritten. In that case, the extent conversion
3383 	 * fits into the credits as well.
3384 	 */
3385 	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3386 	if (IS_ERR(handle))
3387 		return PTR_ERR(handle);
3388 
3389 	/*
3390 	 * DAX and direct I/O are the only two operations that are currently
3391 	 * supported with IOMAP_WRITE.
3392 	 */
3393 	WARN_ON(!(flags & (IOMAP_DAX | IOMAP_DIRECT)));
3394 	if (flags & IOMAP_DAX)
3395 		m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3396 	/*
3397 	 * We use i_size instead of i_disksize here because delalloc writeback
3398 	 * can complete at any point during the I/O and subsequently push the
3399 	 * i_disksize out to i_size. This could be beyond where direct I/O is
3400 	 * happening and thus expose allocated blocks to direct I/O reads.
3401 	 */
3402 	else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
3403 		m_flags = EXT4_GET_BLOCKS_CREATE;
3404 	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3405 		m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3406 
3407 	ret = ext4_map_blocks(handle, inode, map, m_flags);
3408 
3409 	/*
3410 	 * We cannot fill holes in indirect tree based inodes as that could
3411 	 * expose stale data in the case of a crash. Use the magic error code
3412 	 * to fallback to buffered I/O.
3413 	 */
3414 	if (!m_flags && !ret)
3415 		ret = -ENOTBLK;
3416 
3417 	ext4_journal_stop(handle);
3418 	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3419 		goto retry;
3420 
3421 	return ret;
3422 }
3423 
3424 
3425 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3426 		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3427 {
3428 	int ret;
3429 	struct ext4_map_blocks map;
3430 	u8 blkbits = inode->i_blkbits;
3431 
3432 	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3433 		return -EINVAL;
3434 
3435 	if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3436 		return -ERANGE;
3437 
3438 	/*
3439 	 * Calculate the first and last logical blocks respectively.
3440 	 */
3441 	map.m_lblk = offset >> blkbits;
3442 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3443 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3444 
3445 	if (flags & IOMAP_WRITE) {
3446 		/*
3447 		 * We check here if the blocks are already allocated, then we
3448 		 * don't need to start a journal txn and we can directly return
3449 		 * the mapping information. This could boost performance
3450 		 * especially in multi-threaded overwrite requests.
3451 		 */
3452 		if (offset + length <= i_size_read(inode)) {
3453 			ret = ext4_map_blocks(NULL, inode, &map, 0);
3454 			if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
3455 				goto out;
3456 		}
3457 		ret = ext4_iomap_alloc(inode, &map, flags);
3458 	} else {
3459 		ret = ext4_map_blocks(NULL, inode, &map, 0);
3460 	}
3461 
3462 	if (ret < 0)
3463 		return ret;
3464 out:
3465 	/*
3466 	 * When inline encryption is enabled, sometimes I/O to an encrypted file
3467 	 * has to be broken up to guarantee DUN contiguity.  Handle this by
3468 	 * limiting the length of the mapping returned.
3469 	 */
3470 	map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, map.m_len);
3471 
3472 	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
3473 
3474 	return 0;
3475 }
3476 
3477 static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3478 		loff_t length, unsigned flags, struct iomap *iomap,
3479 		struct iomap *srcmap)
3480 {
3481 	int ret;
3482 
3483 	/*
3484 	 * Even for writes we don't need to allocate blocks, so just pretend
3485 	 * we are reading to save overhead of starting a transaction.
3486 	 */
3487 	flags &= ~IOMAP_WRITE;
3488 	ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3489 	WARN_ON_ONCE(iomap->type != IOMAP_MAPPED);
3490 	return ret;
3491 }
3492 
3493 static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3494 			  ssize_t written, unsigned flags, struct iomap *iomap)
3495 {
3496 	/*
3497 	 * Check to see whether an error occurred while writing out the data to
3498 	 * the allocated blocks. If so, return the magic error code so that we
3499 	 * fallback to buffered I/O and attempt to complete the remainder of
3500 	 * the I/O. Any blocks that may have been allocated in preparation for
3501 	 * the direct I/O will be reused during buffered I/O.
3502 	 */
3503 	if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3504 		return -ENOTBLK;
3505 
3506 	return 0;
3507 }
3508 
3509 const struct iomap_ops ext4_iomap_ops = {
3510 	.iomap_begin		= ext4_iomap_begin,
3511 	.iomap_end		= ext4_iomap_end,
3512 };
3513 
3514 const struct iomap_ops ext4_iomap_overwrite_ops = {
3515 	.iomap_begin		= ext4_iomap_overwrite_begin,
3516 	.iomap_end		= ext4_iomap_end,
3517 };
3518 
3519 static bool ext4_iomap_is_delalloc(struct inode *inode,
3520 				   struct ext4_map_blocks *map)
3521 {
3522 	struct extent_status es;
3523 	ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
3524 
3525 	ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
3526 				  map->m_lblk, end, &es);
3527 
3528 	if (!es.es_len || es.es_lblk > end)
3529 		return false;
3530 
3531 	if (es.es_lblk > map->m_lblk) {
3532 		map->m_len = es.es_lblk - map->m_lblk;
3533 		return false;
3534 	}
3535 
3536 	offset = map->m_lblk - es.es_lblk;
3537 	map->m_len = es.es_len - offset;
3538 
3539 	return true;
3540 }
3541 
3542 static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3543 				   loff_t length, unsigned int flags,
3544 				   struct iomap *iomap, struct iomap *srcmap)
3545 {
3546 	int ret;
3547 	bool delalloc = false;
3548 	struct ext4_map_blocks map;
3549 	u8 blkbits = inode->i_blkbits;
3550 
3551 	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3552 		return -EINVAL;
3553 
3554 	if (ext4_has_inline_data(inode)) {
3555 		ret = ext4_inline_data_iomap(inode, iomap);
3556 		if (ret != -EAGAIN) {
3557 			if (ret == 0 && offset >= iomap->length)
3558 				ret = -ENOENT;
3559 			return ret;
3560 		}
3561 	}
3562 
3563 	/*
3564 	 * Calculate the first and last logical block respectively.
3565 	 */
3566 	map.m_lblk = offset >> blkbits;
3567 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3568 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3569 
3570 	/*
3571 	 * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3572 	 * So handle it here itself instead of querying ext4_map_blocks().
3573 	 * Since ext4_map_blocks() will warn about it and will return
3574 	 * -EIO error.
3575 	 */
3576 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3577 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3578 
3579 		if (offset >= sbi->s_bitmap_maxbytes) {
3580 			map.m_flags = 0;
3581 			goto set_iomap;
3582 		}
3583 	}
3584 
3585 	ret = ext4_map_blocks(NULL, inode, &map, 0);
3586 	if (ret < 0)
3587 		return ret;
3588 	if (ret == 0)
3589 		delalloc = ext4_iomap_is_delalloc(inode, &map);
3590 
3591 set_iomap:
3592 	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
3593 	if (delalloc && iomap->type == IOMAP_HOLE)
3594 		iomap->type = IOMAP_DELALLOC;
3595 
3596 	return 0;
3597 }
3598 
3599 const struct iomap_ops ext4_iomap_report_ops = {
3600 	.iomap_begin = ext4_iomap_begin_report,
3601 };
3602 
3603 /*
3604  * Whenever the folio is being dirtied, corresponding buffers should already
3605  * be attached to the transaction (we take care of this in ext4_page_mkwrite()
3606  * and ext4_write_begin()). However we cannot move buffers to dirty transaction
3607  * lists here because ->dirty_folio is called under VFS locks and the folio
3608  * is not necessarily locked.
3609  *
3610  * We cannot just dirty the folio and leave attached buffers clean, because the
3611  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3612  * or jbddirty because all the journalling code will explode.
3613  *
3614  * So what we do is to mark the folio "pending dirty" and next time writepage
3615  * is called, propagate that into the buffers appropriately.
3616  */
3617 static bool ext4_journalled_dirty_folio(struct address_space *mapping,
3618 		struct folio *folio)
3619 {
3620 	WARN_ON_ONCE(!folio_buffers(folio));
3621 	folio_set_checked(folio);
3622 	return filemap_dirty_folio(mapping, folio);
3623 }
3624 
3625 static bool ext4_dirty_folio(struct address_space *mapping, struct folio *folio)
3626 {
3627 	WARN_ON_ONCE(!folio_test_locked(folio) && !folio_test_dirty(folio));
3628 	WARN_ON_ONCE(!folio_buffers(folio));
3629 	return block_dirty_folio(mapping, folio);
3630 }
3631 
3632 static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3633 				    struct file *file, sector_t *span)
3634 {
3635 	return iomap_swapfile_activate(sis, file, span,
3636 				       &ext4_iomap_report_ops);
3637 }
3638 
3639 static const struct address_space_operations ext4_aops = {
3640 	.read_folio		= ext4_read_folio,
3641 	.readahead		= ext4_readahead,
3642 	.writepage		= ext4_writepage,
3643 	.writepages		= ext4_writepages,
3644 	.write_begin		= ext4_write_begin,
3645 	.write_end		= ext4_write_end,
3646 	.dirty_folio		= ext4_dirty_folio,
3647 	.bmap			= ext4_bmap,
3648 	.invalidate_folio	= ext4_invalidate_folio,
3649 	.release_folio		= ext4_release_folio,
3650 	.direct_IO		= noop_direct_IO,
3651 	.migrate_folio		= buffer_migrate_folio,
3652 	.is_partially_uptodate  = block_is_partially_uptodate,
3653 	.error_remove_page	= generic_error_remove_page,
3654 	.swap_activate		= ext4_iomap_swap_activate,
3655 };
3656 
3657 static const struct address_space_operations ext4_journalled_aops = {
3658 	.read_folio		= ext4_read_folio,
3659 	.readahead		= ext4_readahead,
3660 	.writepage		= ext4_writepage,
3661 	.writepages		= ext4_writepages,
3662 	.write_begin		= ext4_write_begin,
3663 	.write_end		= ext4_journalled_write_end,
3664 	.dirty_folio		= ext4_journalled_dirty_folio,
3665 	.bmap			= ext4_bmap,
3666 	.invalidate_folio	= ext4_journalled_invalidate_folio,
3667 	.release_folio		= ext4_release_folio,
3668 	.direct_IO		= noop_direct_IO,
3669 	.is_partially_uptodate  = block_is_partially_uptodate,
3670 	.error_remove_page	= generic_error_remove_page,
3671 	.swap_activate		= ext4_iomap_swap_activate,
3672 };
3673 
3674 static const struct address_space_operations ext4_da_aops = {
3675 	.read_folio		= ext4_read_folio,
3676 	.readahead		= ext4_readahead,
3677 	.writepage		= ext4_writepage,
3678 	.writepages		= ext4_writepages,
3679 	.write_begin		= ext4_da_write_begin,
3680 	.write_end		= ext4_da_write_end,
3681 	.dirty_folio		= ext4_dirty_folio,
3682 	.bmap			= ext4_bmap,
3683 	.invalidate_folio	= ext4_invalidate_folio,
3684 	.release_folio		= ext4_release_folio,
3685 	.direct_IO		= noop_direct_IO,
3686 	.migrate_folio		= buffer_migrate_folio,
3687 	.is_partially_uptodate  = block_is_partially_uptodate,
3688 	.error_remove_page	= generic_error_remove_page,
3689 	.swap_activate		= ext4_iomap_swap_activate,
3690 };
3691 
3692 static const struct address_space_operations ext4_dax_aops = {
3693 	.writepages		= ext4_dax_writepages,
3694 	.direct_IO		= noop_direct_IO,
3695 	.dirty_folio		= noop_dirty_folio,
3696 	.bmap			= ext4_bmap,
3697 	.swap_activate		= ext4_iomap_swap_activate,
3698 };
3699 
3700 void ext4_set_aops(struct inode *inode)
3701 {
3702 	switch (ext4_inode_journal_mode(inode)) {
3703 	case EXT4_INODE_ORDERED_DATA_MODE:
3704 	case EXT4_INODE_WRITEBACK_DATA_MODE:
3705 		break;
3706 	case EXT4_INODE_JOURNAL_DATA_MODE:
3707 		inode->i_mapping->a_ops = &ext4_journalled_aops;
3708 		return;
3709 	default:
3710 		BUG();
3711 	}
3712 	if (IS_DAX(inode))
3713 		inode->i_mapping->a_ops = &ext4_dax_aops;
3714 	else if (test_opt(inode->i_sb, DELALLOC))
3715 		inode->i_mapping->a_ops = &ext4_da_aops;
3716 	else
3717 		inode->i_mapping->a_ops = &ext4_aops;
3718 }
3719 
3720 static int __ext4_block_zero_page_range(handle_t *handle,
3721 		struct address_space *mapping, loff_t from, loff_t length)
3722 {
3723 	ext4_fsblk_t index = from >> PAGE_SHIFT;
3724 	unsigned offset = from & (PAGE_SIZE-1);
3725 	unsigned blocksize, pos;
3726 	ext4_lblk_t iblock;
3727 	struct inode *inode = mapping->host;
3728 	struct buffer_head *bh;
3729 	struct page *page;
3730 	int err = 0;
3731 
3732 	page = find_or_create_page(mapping, from >> PAGE_SHIFT,
3733 				   mapping_gfp_constraint(mapping, ~__GFP_FS));
3734 	if (!page)
3735 		return -ENOMEM;
3736 
3737 	blocksize = inode->i_sb->s_blocksize;
3738 
3739 	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3740 
3741 	if (!page_has_buffers(page))
3742 		create_empty_buffers(page, blocksize, 0);
3743 
3744 	/* Find the buffer that contains "offset" */
3745 	bh = page_buffers(page);
3746 	pos = blocksize;
3747 	while (offset >= pos) {
3748 		bh = bh->b_this_page;
3749 		iblock++;
3750 		pos += blocksize;
3751 	}
3752 	if (buffer_freed(bh)) {
3753 		BUFFER_TRACE(bh, "freed: skip");
3754 		goto unlock;
3755 	}
3756 	if (!buffer_mapped(bh)) {
3757 		BUFFER_TRACE(bh, "unmapped");
3758 		ext4_get_block(inode, iblock, bh, 0);
3759 		/* unmapped? It's a hole - nothing to do */
3760 		if (!buffer_mapped(bh)) {
3761 			BUFFER_TRACE(bh, "still unmapped");
3762 			goto unlock;
3763 		}
3764 	}
3765 
3766 	/* Ok, it's mapped. Make sure it's up-to-date */
3767 	if (PageUptodate(page))
3768 		set_buffer_uptodate(bh);
3769 
3770 	if (!buffer_uptodate(bh)) {
3771 		err = ext4_read_bh_lock(bh, 0, true);
3772 		if (err)
3773 			goto unlock;
3774 		if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3775 			/* We expect the key to be set. */
3776 			BUG_ON(!fscrypt_has_encryption_key(inode));
3777 			err = fscrypt_decrypt_pagecache_blocks(page, blocksize,
3778 							       bh_offset(bh));
3779 			if (err) {
3780 				clear_buffer_uptodate(bh);
3781 				goto unlock;
3782 			}
3783 		}
3784 	}
3785 	if (ext4_should_journal_data(inode)) {
3786 		BUFFER_TRACE(bh, "get write access");
3787 		err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
3788 						    EXT4_JTR_NONE);
3789 		if (err)
3790 			goto unlock;
3791 	}
3792 	zero_user(page, offset, length);
3793 	BUFFER_TRACE(bh, "zeroed end of block");
3794 
3795 	if (ext4_should_journal_data(inode)) {
3796 		err = ext4_handle_dirty_metadata(handle, inode, bh);
3797 	} else {
3798 		err = 0;
3799 		mark_buffer_dirty(bh);
3800 		if (ext4_should_order_data(inode))
3801 			err = ext4_jbd2_inode_add_write(handle, inode, from,
3802 					length);
3803 	}
3804 
3805 unlock:
3806 	unlock_page(page);
3807 	put_page(page);
3808 	return err;
3809 }
3810 
3811 /*
3812  * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3813  * starting from file offset 'from'.  The range to be zero'd must
3814  * be contained with in one block.  If the specified range exceeds
3815  * the end of the block it will be shortened to end of the block
3816  * that corresponds to 'from'
3817  */
3818 static int ext4_block_zero_page_range(handle_t *handle,
3819 		struct address_space *mapping, loff_t from, loff_t length)
3820 {
3821 	struct inode *inode = mapping->host;
3822 	unsigned offset = from & (PAGE_SIZE-1);
3823 	unsigned blocksize = inode->i_sb->s_blocksize;
3824 	unsigned max = blocksize - (offset & (blocksize - 1));
3825 
3826 	/*
3827 	 * correct length if it does not fall between
3828 	 * 'from' and the end of the block
3829 	 */
3830 	if (length > max || length < 0)
3831 		length = max;
3832 
3833 	if (IS_DAX(inode)) {
3834 		return dax_zero_range(inode, from, length, NULL,
3835 				      &ext4_iomap_ops);
3836 	}
3837 	return __ext4_block_zero_page_range(handle, mapping, from, length);
3838 }
3839 
3840 /*
3841  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3842  * up to the end of the block which corresponds to `from'.
3843  * This required during truncate. We need to physically zero the tail end
3844  * of that block so it doesn't yield old data if the file is later grown.
3845  */
3846 static int ext4_block_truncate_page(handle_t *handle,
3847 		struct address_space *mapping, loff_t from)
3848 {
3849 	unsigned offset = from & (PAGE_SIZE-1);
3850 	unsigned length;
3851 	unsigned blocksize;
3852 	struct inode *inode = mapping->host;
3853 
3854 	/* If we are processing an encrypted inode during orphan list handling */
3855 	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3856 		return 0;
3857 
3858 	blocksize = inode->i_sb->s_blocksize;
3859 	length = blocksize - (offset & (blocksize - 1));
3860 
3861 	return ext4_block_zero_page_range(handle, mapping, from, length);
3862 }
3863 
3864 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3865 			     loff_t lstart, loff_t length)
3866 {
3867 	struct super_block *sb = inode->i_sb;
3868 	struct address_space *mapping = inode->i_mapping;
3869 	unsigned partial_start, partial_end;
3870 	ext4_fsblk_t start, end;
3871 	loff_t byte_end = (lstart + length - 1);
3872 	int err = 0;
3873 
3874 	partial_start = lstart & (sb->s_blocksize - 1);
3875 	partial_end = byte_end & (sb->s_blocksize - 1);
3876 
3877 	start = lstart >> sb->s_blocksize_bits;
3878 	end = byte_end >> sb->s_blocksize_bits;
3879 
3880 	/* Handle partial zero within the single block */
3881 	if (start == end &&
3882 	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
3883 		err = ext4_block_zero_page_range(handle, mapping,
3884 						 lstart, length);
3885 		return err;
3886 	}
3887 	/* Handle partial zero out on the start of the range */
3888 	if (partial_start) {
3889 		err = ext4_block_zero_page_range(handle, mapping,
3890 						 lstart, sb->s_blocksize);
3891 		if (err)
3892 			return err;
3893 	}
3894 	/* Handle partial zero out on the end of the range */
3895 	if (partial_end != sb->s_blocksize - 1)
3896 		err = ext4_block_zero_page_range(handle, mapping,
3897 						 byte_end - partial_end,
3898 						 partial_end + 1);
3899 	return err;
3900 }
3901 
3902 int ext4_can_truncate(struct inode *inode)
3903 {
3904 	if (S_ISREG(inode->i_mode))
3905 		return 1;
3906 	if (S_ISDIR(inode->i_mode))
3907 		return 1;
3908 	if (S_ISLNK(inode->i_mode))
3909 		return !ext4_inode_is_fast_symlink(inode);
3910 	return 0;
3911 }
3912 
3913 /*
3914  * We have to make sure i_disksize gets properly updated before we truncate
3915  * page cache due to hole punching or zero range. Otherwise i_disksize update
3916  * can get lost as it may have been postponed to submission of writeback but
3917  * that will never happen after we truncate page cache.
3918  */
3919 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3920 				      loff_t len)
3921 {
3922 	handle_t *handle;
3923 	int ret;
3924 
3925 	loff_t size = i_size_read(inode);
3926 
3927 	WARN_ON(!inode_is_locked(inode));
3928 	if (offset > size || offset + len < size)
3929 		return 0;
3930 
3931 	if (EXT4_I(inode)->i_disksize >= size)
3932 		return 0;
3933 
3934 	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3935 	if (IS_ERR(handle))
3936 		return PTR_ERR(handle);
3937 	ext4_update_i_disksize(inode, size);
3938 	ret = ext4_mark_inode_dirty(handle, inode);
3939 	ext4_journal_stop(handle);
3940 
3941 	return ret;
3942 }
3943 
3944 static void ext4_wait_dax_page(struct inode *inode)
3945 {
3946 	filemap_invalidate_unlock(inode->i_mapping);
3947 	schedule();
3948 	filemap_invalidate_lock(inode->i_mapping);
3949 }
3950 
3951 int ext4_break_layouts(struct inode *inode)
3952 {
3953 	struct page *page;
3954 	int error;
3955 
3956 	if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock)))
3957 		return -EINVAL;
3958 
3959 	do {
3960 		page = dax_layout_busy_page(inode->i_mapping);
3961 		if (!page)
3962 			return 0;
3963 
3964 		error = ___wait_var_event(&page->_refcount,
3965 				atomic_read(&page->_refcount) == 1,
3966 				TASK_INTERRUPTIBLE, 0, 0,
3967 				ext4_wait_dax_page(inode));
3968 	} while (error == 0);
3969 
3970 	return error;
3971 }
3972 
3973 /*
3974  * ext4_punch_hole: punches a hole in a file by releasing the blocks
3975  * associated with the given offset and length
3976  *
3977  * @inode:  File inode
3978  * @offset: The offset where the hole will begin
3979  * @len:    The length of the hole
3980  *
3981  * Returns: 0 on success or negative on failure
3982  */
3983 
3984 int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
3985 {
3986 	struct inode *inode = file_inode(file);
3987 	struct super_block *sb = inode->i_sb;
3988 	ext4_lblk_t first_block, stop_block;
3989 	struct address_space *mapping = inode->i_mapping;
3990 	loff_t first_block_offset, last_block_offset, max_length;
3991 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3992 	handle_t *handle;
3993 	unsigned int credits;
3994 	int ret = 0, ret2 = 0;
3995 
3996 	trace_ext4_punch_hole(inode, offset, length, 0);
3997 
3998 	/*
3999 	 * Write out all dirty pages to avoid race conditions
4000 	 * Then release them.
4001 	 */
4002 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
4003 		ret = filemap_write_and_wait_range(mapping, offset,
4004 						   offset + length - 1);
4005 		if (ret)
4006 			return ret;
4007 	}
4008 
4009 	inode_lock(inode);
4010 
4011 	/* No need to punch hole beyond i_size */
4012 	if (offset >= inode->i_size)
4013 		goto out_mutex;
4014 
4015 	/*
4016 	 * If the hole extends beyond i_size, set the hole
4017 	 * to end after the page that contains i_size
4018 	 */
4019 	if (offset + length > inode->i_size) {
4020 		length = inode->i_size +
4021 		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
4022 		   offset;
4023 	}
4024 
4025 	/*
4026 	 * For punch hole the length + offset needs to be within one block
4027 	 * before last range. Adjust the length if it goes beyond that limit.
4028 	 */
4029 	max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize;
4030 	if (offset + length > max_length)
4031 		length = max_length - offset;
4032 
4033 	if (offset & (sb->s_blocksize - 1) ||
4034 	    (offset + length) & (sb->s_blocksize - 1)) {
4035 		/*
4036 		 * Attach jinode to inode for jbd2 if we do any zeroing of
4037 		 * partial block
4038 		 */
4039 		ret = ext4_inode_attach_jinode(inode);
4040 		if (ret < 0)
4041 			goto out_mutex;
4042 
4043 	}
4044 
4045 	/* Wait all existing dio workers, newcomers will block on i_rwsem */
4046 	inode_dio_wait(inode);
4047 
4048 	ret = file_modified(file);
4049 	if (ret)
4050 		goto out_mutex;
4051 
4052 	/*
4053 	 * Prevent page faults from reinstantiating pages we have released from
4054 	 * page cache.
4055 	 */
4056 	filemap_invalidate_lock(mapping);
4057 
4058 	ret = ext4_break_layouts(inode);
4059 	if (ret)
4060 		goto out_dio;
4061 
4062 	first_block_offset = round_up(offset, sb->s_blocksize);
4063 	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4064 
4065 	/* Now release the pages and zero block aligned part of pages*/
4066 	if (last_block_offset > first_block_offset) {
4067 		ret = ext4_update_disksize_before_punch(inode, offset, length);
4068 		if (ret)
4069 			goto out_dio;
4070 		truncate_pagecache_range(inode, first_block_offset,
4071 					 last_block_offset);
4072 	}
4073 
4074 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4075 		credits = ext4_writepage_trans_blocks(inode);
4076 	else
4077 		credits = ext4_blocks_for_truncate(inode);
4078 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4079 	if (IS_ERR(handle)) {
4080 		ret = PTR_ERR(handle);
4081 		ext4_std_error(sb, ret);
4082 		goto out_dio;
4083 	}
4084 
4085 	ret = ext4_zero_partial_blocks(handle, inode, offset,
4086 				       length);
4087 	if (ret)
4088 		goto out_stop;
4089 
4090 	first_block = (offset + sb->s_blocksize - 1) >>
4091 		EXT4_BLOCK_SIZE_BITS(sb);
4092 	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4093 
4094 	/* If there are blocks to remove, do it */
4095 	if (stop_block > first_block) {
4096 
4097 		down_write(&EXT4_I(inode)->i_data_sem);
4098 		ext4_discard_preallocations(inode, 0);
4099 
4100 		ret = ext4_es_remove_extent(inode, first_block,
4101 					    stop_block - first_block);
4102 		if (ret) {
4103 			up_write(&EXT4_I(inode)->i_data_sem);
4104 			goto out_stop;
4105 		}
4106 
4107 		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4108 			ret = ext4_ext_remove_space(inode, first_block,
4109 						    stop_block - 1);
4110 		else
4111 			ret = ext4_ind_remove_space(handle, inode, first_block,
4112 						    stop_block);
4113 
4114 		up_write(&EXT4_I(inode)->i_data_sem);
4115 	}
4116 	ext4_fc_track_range(handle, inode, first_block, stop_block);
4117 	if (IS_SYNC(inode))
4118 		ext4_handle_sync(handle);
4119 
4120 	inode->i_mtime = inode->i_ctime = current_time(inode);
4121 	ret2 = ext4_mark_inode_dirty(handle, inode);
4122 	if (unlikely(ret2))
4123 		ret = ret2;
4124 	if (ret >= 0)
4125 		ext4_update_inode_fsync_trans(handle, inode, 1);
4126 out_stop:
4127 	ext4_journal_stop(handle);
4128 out_dio:
4129 	filemap_invalidate_unlock(mapping);
4130 out_mutex:
4131 	inode_unlock(inode);
4132 	return ret;
4133 }
4134 
4135 int ext4_inode_attach_jinode(struct inode *inode)
4136 {
4137 	struct ext4_inode_info *ei = EXT4_I(inode);
4138 	struct jbd2_inode *jinode;
4139 
4140 	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4141 		return 0;
4142 
4143 	jinode = jbd2_alloc_inode(GFP_KERNEL);
4144 	spin_lock(&inode->i_lock);
4145 	if (!ei->jinode) {
4146 		if (!jinode) {
4147 			spin_unlock(&inode->i_lock);
4148 			return -ENOMEM;
4149 		}
4150 		ei->jinode = jinode;
4151 		jbd2_journal_init_jbd_inode(ei->jinode, inode);
4152 		jinode = NULL;
4153 	}
4154 	spin_unlock(&inode->i_lock);
4155 	if (unlikely(jinode != NULL))
4156 		jbd2_free_inode(jinode);
4157 	return 0;
4158 }
4159 
4160 /*
4161  * ext4_truncate()
4162  *
4163  * We block out ext4_get_block() block instantiations across the entire
4164  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4165  * simultaneously on behalf of the same inode.
4166  *
4167  * As we work through the truncate and commit bits of it to the journal there
4168  * is one core, guiding principle: the file's tree must always be consistent on
4169  * disk.  We must be able to restart the truncate after a crash.
4170  *
4171  * The file's tree may be transiently inconsistent in memory (although it
4172  * probably isn't), but whenever we close off and commit a journal transaction,
4173  * the contents of (the filesystem + the journal) must be consistent and
4174  * restartable.  It's pretty simple, really: bottom up, right to left (although
4175  * left-to-right works OK too).
4176  *
4177  * Note that at recovery time, journal replay occurs *before* the restart of
4178  * truncate against the orphan inode list.
4179  *
4180  * The committed inode has the new, desired i_size (which is the same as
4181  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4182  * that this inode's truncate did not complete and it will again call
4183  * ext4_truncate() to have another go.  So there will be instantiated blocks
4184  * to the right of the truncation point in a crashed ext4 filesystem.  But
4185  * that's fine - as long as they are linked from the inode, the post-crash
4186  * ext4_truncate() run will find them and release them.
4187  */
4188 int ext4_truncate(struct inode *inode)
4189 {
4190 	struct ext4_inode_info *ei = EXT4_I(inode);
4191 	unsigned int credits;
4192 	int err = 0, err2;
4193 	handle_t *handle;
4194 	struct address_space *mapping = inode->i_mapping;
4195 
4196 	/*
4197 	 * There is a possibility that we're either freeing the inode
4198 	 * or it's a completely new inode. In those cases we might not
4199 	 * have i_rwsem locked because it's not necessary.
4200 	 */
4201 	if (!(inode->i_state & (I_NEW|I_FREEING)))
4202 		WARN_ON(!inode_is_locked(inode));
4203 	trace_ext4_truncate_enter(inode);
4204 
4205 	if (!ext4_can_truncate(inode))
4206 		goto out_trace;
4207 
4208 	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4209 		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4210 
4211 	if (ext4_has_inline_data(inode)) {
4212 		int has_inline = 1;
4213 
4214 		err = ext4_inline_data_truncate(inode, &has_inline);
4215 		if (err || has_inline)
4216 			goto out_trace;
4217 	}
4218 
4219 	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
4220 	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4221 		if (ext4_inode_attach_jinode(inode) < 0)
4222 			goto out_trace;
4223 	}
4224 
4225 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4226 		credits = ext4_writepage_trans_blocks(inode);
4227 	else
4228 		credits = ext4_blocks_for_truncate(inode);
4229 
4230 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4231 	if (IS_ERR(handle)) {
4232 		err = PTR_ERR(handle);
4233 		goto out_trace;
4234 	}
4235 
4236 	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4237 		ext4_block_truncate_page(handle, mapping, inode->i_size);
4238 
4239 	/*
4240 	 * We add the inode to the orphan list, so that if this
4241 	 * truncate spans multiple transactions, and we crash, we will
4242 	 * resume the truncate when the filesystem recovers.  It also
4243 	 * marks the inode dirty, to catch the new size.
4244 	 *
4245 	 * Implication: the file must always be in a sane, consistent
4246 	 * truncatable state while each transaction commits.
4247 	 */
4248 	err = ext4_orphan_add(handle, inode);
4249 	if (err)
4250 		goto out_stop;
4251 
4252 	down_write(&EXT4_I(inode)->i_data_sem);
4253 
4254 	ext4_discard_preallocations(inode, 0);
4255 
4256 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4257 		err = ext4_ext_truncate(handle, inode);
4258 	else
4259 		ext4_ind_truncate(handle, inode);
4260 
4261 	up_write(&ei->i_data_sem);
4262 	if (err)
4263 		goto out_stop;
4264 
4265 	if (IS_SYNC(inode))
4266 		ext4_handle_sync(handle);
4267 
4268 out_stop:
4269 	/*
4270 	 * If this was a simple ftruncate() and the file will remain alive,
4271 	 * then we need to clear up the orphan record which we created above.
4272 	 * However, if this was a real unlink then we were called by
4273 	 * ext4_evict_inode(), and we allow that function to clean up the
4274 	 * orphan info for us.
4275 	 */
4276 	if (inode->i_nlink)
4277 		ext4_orphan_del(handle, inode);
4278 
4279 	inode->i_mtime = inode->i_ctime = current_time(inode);
4280 	err2 = ext4_mark_inode_dirty(handle, inode);
4281 	if (unlikely(err2 && !err))
4282 		err = err2;
4283 	ext4_journal_stop(handle);
4284 
4285 out_trace:
4286 	trace_ext4_truncate_exit(inode);
4287 	return err;
4288 }
4289 
4290 static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4291 {
4292 	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4293 		return inode_peek_iversion_raw(inode);
4294 	else
4295 		return inode_peek_iversion(inode);
4296 }
4297 
4298 static int ext4_inode_blocks_set(struct ext4_inode *raw_inode,
4299 				 struct ext4_inode_info *ei)
4300 {
4301 	struct inode *inode = &(ei->vfs_inode);
4302 	u64 i_blocks = READ_ONCE(inode->i_blocks);
4303 	struct super_block *sb = inode->i_sb;
4304 
4305 	if (i_blocks <= ~0U) {
4306 		/*
4307 		 * i_blocks can be represented in a 32 bit variable
4308 		 * as multiple of 512 bytes
4309 		 */
4310 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4311 		raw_inode->i_blocks_high = 0;
4312 		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4313 		return 0;
4314 	}
4315 
4316 	/*
4317 	 * This should never happen since sb->s_maxbytes should not have
4318 	 * allowed this, sb->s_maxbytes was set according to the huge_file
4319 	 * feature in ext4_fill_super().
4320 	 */
4321 	if (!ext4_has_feature_huge_file(sb))
4322 		return -EFSCORRUPTED;
4323 
4324 	if (i_blocks <= 0xffffffffffffULL) {
4325 		/*
4326 		 * i_blocks can be represented in a 48 bit variable
4327 		 * as multiple of 512 bytes
4328 		 */
4329 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4330 		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4331 		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4332 	} else {
4333 		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4334 		/* i_block is stored in file system block size */
4335 		i_blocks = i_blocks >> (inode->i_blkbits - 9);
4336 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4337 		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4338 	}
4339 	return 0;
4340 }
4341 
4342 static int ext4_fill_raw_inode(struct inode *inode, struct ext4_inode *raw_inode)
4343 {
4344 	struct ext4_inode_info *ei = EXT4_I(inode);
4345 	uid_t i_uid;
4346 	gid_t i_gid;
4347 	projid_t i_projid;
4348 	int block;
4349 	int err;
4350 
4351 	err = ext4_inode_blocks_set(raw_inode, ei);
4352 
4353 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4354 	i_uid = i_uid_read(inode);
4355 	i_gid = i_gid_read(inode);
4356 	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4357 	if (!(test_opt(inode->i_sb, NO_UID32))) {
4358 		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4359 		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4360 		/*
4361 		 * Fix up interoperability with old kernels. Otherwise,
4362 		 * old inodes get re-used with the upper 16 bits of the
4363 		 * uid/gid intact.
4364 		 */
4365 		if (ei->i_dtime && list_empty(&ei->i_orphan)) {
4366 			raw_inode->i_uid_high = 0;
4367 			raw_inode->i_gid_high = 0;
4368 		} else {
4369 			raw_inode->i_uid_high =
4370 				cpu_to_le16(high_16_bits(i_uid));
4371 			raw_inode->i_gid_high =
4372 				cpu_to_le16(high_16_bits(i_gid));
4373 		}
4374 	} else {
4375 		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4376 		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4377 		raw_inode->i_uid_high = 0;
4378 		raw_inode->i_gid_high = 0;
4379 	}
4380 	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4381 
4382 	EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4383 	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4384 	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4385 	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4386 
4387 	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4388 	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4389 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4390 		raw_inode->i_file_acl_high =
4391 			cpu_to_le16(ei->i_file_acl >> 32);
4392 	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4393 	ext4_isize_set(raw_inode, ei->i_disksize);
4394 
4395 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4396 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4397 		if (old_valid_dev(inode->i_rdev)) {
4398 			raw_inode->i_block[0] =
4399 				cpu_to_le32(old_encode_dev(inode->i_rdev));
4400 			raw_inode->i_block[1] = 0;
4401 		} else {
4402 			raw_inode->i_block[0] = 0;
4403 			raw_inode->i_block[1] =
4404 				cpu_to_le32(new_encode_dev(inode->i_rdev));
4405 			raw_inode->i_block[2] = 0;
4406 		}
4407 	} else if (!ext4_has_inline_data(inode)) {
4408 		for (block = 0; block < EXT4_N_BLOCKS; block++)
4409 			raw_inode->i_block[block] = ei->i_data[block];
4410 	}
4411 
4412 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4413 		u64 ivers = ext4_inode_peek_iversion(inode);
4414 
4415 		raw_inode->i_disk_version = cpu_to_le32(ivers);
4416 		if (ei->i_extra_isize) {
4417 			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4418 				raw_inode->i_version_hi =
4419 					cpu_to_le32(ivers >> 32);
4420 			raw_inode->i_extra_isize =
4421 				cpu_to_le16(ei->i_extra_isize);
4422 		}
4423 	}
4424 
4425 	if (i_projid != EXT4_DEF_PROJID &&
4426 	    !ext4_has_feature_project(inode->i_sb))
4427 		err = err ?: -EFSCORRUPTED;
4428 
4429 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4430 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4431 		raw_inode->i_projid = cpu_to_le32(i_projid);
4432 
4433 	ext4_inode_csum_set(inode, raw_inode, ei);
4434 	return err;
4435 }
4436 
4437 /*
4438  * ext4_get_inode_loc returns with an extra refcount against the inode's
4439  * underlying buffer_head on success. If we pass 'inode' and it does not
4440  * have in-inode xattr, we have all inode data in memory that is needed
4441  * to recreate the on-disk version of this inode.
4442  */
4443 static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
4444 				struct inode *inode, struct ext4_iloc *iloc,
4445 				ext4_fsblk_t *ret_block)
4446 {
4447 	struct ext4_group_desc	*gdp;
4448 	struct buffer_head	*bh;
4449 	ext4_fsblk_t		block;
4450 	struct blk_plug		plug;
4451 	int			inodes_per_block, inode_offset;
4452 
4453 	iloc->bh = NULL;
4454 	if (ino < EXT4_ROOT_INO ||
4455 	    ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4456 		return -EFSCORRUPTED;
4457 
4458 	iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
4459 	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4460 	if (!gdp)
4461 		return -EIO;
4462 
4463 	/*
4464 	 * Figure out the offset within the block group inode table
4465 	 */
4466 	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4467 	inode_offset = ((ino - 1) %
4468 			EXT4_INODES_PER_GROUP(sb));
4469 	block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4470 	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4471 
4472 	bh = sb_getblk(sb, block);
4473 	if (unlikely(!bh))
4474 		return -ENOMEM;
4475 	if (ext4_buffer_uptodate(bh))
4476 		goto has_buffer;
4477 
4478 	lock_buffer(bh);
4479 	if (ext4_buffer_uptodate(bh)) {
4480 		/* Someone brought it uptodate while we waited */
4481 		unlock_buffer(bh);
4482 		goto has_buffer;
4483 	}
4484 
4485 	/*
4486 	 * If we have all information of the inode in memory and this
4487 	 * is the only valid inode in the block, we need not read the
4488 	 * block.
4489 	 */
4490 	if (inode && !ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4491 		struct buffer_head *bitmap_bh;
4492 		int i, start;
4493 
4494 		start = inode_offset & ~(inodes_per_block - 1);
4495 
4496 		/* Is the inode bitmap in cache? */
4497 		bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4498 		if (unlikely(!bitmap_bh))
4499 			goto make_io;
4500 
4501 		/*
4502 		 * If the inode bitmap isn't in cache then the
4503 		 * optimisation may end up performing two reads instead
4504 		 * of one, so skip it.
4505 		 */
4506 		if (!buffer_uptodate(bitmap_bh)) {
4507 			brelse(bitmap_bh);
4508 			goto make_io;
4509 		}
4510 		for (i = start; i < start + inodes_per_block; i++) {
4511 			if (i == inode_offset)
4512 				continue;
4513 			if (ext4_test_bit(i, bitmap_bh->b_data))
4514 				break;
4515 		}
4516 		brelse(bitmap_bh);
4517 		if (i == start + inodes_per_block) {
4518 			struct ext4_inode *raw_inode =
4519 				(struct ext4_inode *) (bh->b_data + iloc->offset);
4520 
4521 			/* all other inodes are free, so skip I/O */
4522 			memset(bh->b_data, 0, bh->b_size);
4523 			if (!ext4_test_inode_state(inode, EXT4_STATE_NEW))
4524 				ext4_fill_raw_inode(inode, raw_inode);
4525 			set_buffer_uptodate(bh);
4526 			unlock_buffer(bh);
4527 			goto has_buffer;
4528 		}
4529 	}
4530 
4531 make_io:
4532 	/*
4533 	 * If we need to do any I/O, try to pre-readahead extra
4534 	 * blocks from the inode table.
4535 	 */
4536 	blk_start_plug(&plug);
4537 	if (EXT4_SB(sb)->s_inode_readahead_blks) {
4538 		ext4_fsblk_t b, end, table;
4539 		unsigned num;
4540 		__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4541 
4542 		table = ext4_inode_table(sb, gdp);
4543 		/* s_inode_readahead_blks is always a power of 2 */
4544 		b = block & ~((ext4_fsblk_t) ra_blks - 1);
4545 		if (table > b)
4546 			b = table;
4547 		end = b + ra_blks;
4548 		num = EXT4_INODES_PER_GROUP(sb);
4549 		if (ext4_has_group_desc_csum(sb))
4550 			num -= ext4_itable_unused_count(sb, gdp);
4551 		table += num / inodes_per_block;
4552 		if (end > table)
4553 			end = table;
4554 		while (b <= end)
4555 			ext4_sb_breadahead_unmovable(sb, b++);
4556 	}
4557 
4558 	/*
4559 	 * There are other valid inodes in the buffer, this inode
4560 	 * has in-inode xattrs, or we don't have this inode in memory.
4561 	 * Read the block from disk.
4562 	 */
4563 	trace_ext4_load_inode(sb, ino);
4564 	ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
4565 	blk_finish_plug(&plug);
4566 	wait_on_buffer(bh);
4567 	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
4568 	if (!buffer_uptodate(bh)) {
4569 		if (ret_block)
4570 			*ret_block = block;
4571 		brelse(bh);
4572 		return -EIO;
4573 	}
4574 has_buffer:
4575 	iloc->bh = bh;
4576 	return 0;
4577 }
4578 
4579 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4580 					struct ext4_iloc *iloc)
4581 {
4582 	ext4_fsblk_t err_blk = 0;
4583 	int ret;
4584 
4585 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, NULL, iloc,
4586 					&err_blk);
4587 
4588 	if (ret == -EIO)
4589 		ext4_error_inode_block(inode, err_blk, EIO,
4590 					"unable to read itable block");
4591 
4592 	return ret;
4593 }
4594 
4595 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4596 {
4597 	ext4_fsblk_t err_blk = 0;
4598 	int ret;
4599 
4600 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, inode, iloc,
4601 					&err_blk);
4602 
4603 	if (ret == -EIO)
4604 		ext4_error_inode_block(inode, err_blk, EIO,
4605 					"unable to read itable block");
4606 
4607 	return ret;
4608 }
4609 
4610 
4611 int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
4612 			  struct ext4_iloc *iloc)
4613 {
4614 	return __ext4_get_inode_loc(sb, ino, NULL, iloc, NULL);
4615 }
4616 
4617 static bool ext4_should_enable_dax(struct inode *inode)
4618 {
4619 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4620 
4621 	if (test_opt2(inode->i_sb, DAX_NEVER))
4622 		return false;
4623 	if (!S_ISREG(inode->i_mode))
4624 		return false;
4625 	if (ext4_should_journal_data(inode))
4626 		return false;
4627 	if (ext4_has_inline_data(inode))
4628 		return false;
4629 	if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4630 		return false;
4631 	if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4632 		return false;
4633 	if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4634 		return false;
4635 	if (test_opt(inode->i_sb, DAX_ALWAYS))
4636 		return true;
4637 
4638 	return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4639 }
4640 
4641 void ext4_set_inode_flags(struct inode *inode, bool init)
4642 {
4643 	unsigned int flags = EXT4_I(inode)->i_flags;
4644 	unsigned int new_fl = 0;
4645 
4646 	WARN_ON_ONCE(IS_DAX(inode) && init);
4647 
4648 	if (flags & EXT4_SYNC_FL)
4649 		new_fl |= S_SYNC;
4650 	if (flags & EXT4_APPEND_FL)
4651 		new_fl |= S_APPEND;
4652 	if (flags & EXT4_IMMUTABLE_FL)
4653 		new_fl |= S_IMMUTABLE;
4654 	if (flags & EXT4_NOATIME_FL)
4655 		new_fl |= S_NOATIME;
4656 	if (flags & EXT4_DIRSYNC_FL)
4657 		new_fl |= S_DIRSYNC;
4658 
4659 	/* Because of the way inode_set_flags() works we must preserve S_DAX
4660 	 * here if already set. */
4661 	new_fl |= (inode->i_flags & S_DAX);
4662 	if (init && ext4_should_enable_dax(inode))
4663 		new_fl |= S_DAX;
4664 
4665 	if (flags & EXT4_ENCRYPT_FL)
4666 		new_fl |= S_ENCRYPTED;
4667 	if (flags & EXT4_CASEFOLD_FL)
4668 		new_fl |= S_CASEFOLD;
4669 	if (flags & EXT4_VERITY_FL)
4670 		new_fl |= S_VERITY;
4671 	inode_set_flags(inode, new_fl,
4672 			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4673 			S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4674 }
4675 
4676 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4677 				  struct ext4_inode_info *ei)
4678 {
4679 	blkcnt_t i_blocks ;
4680 	struct inode *inode = &(ei->vfs_inode);
4681 	struct super_block *sb = inode->i_sb;
4682 
4683 	if (ext4_has_feature_huge_file(sb)) {
4684 		/* we are using combined 48 bit field */
4685 		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4686 					le32_to_cpu(raw_inode->i_blocks_lo);
4687 		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4688 			/* i_blocks represent file system block size */
4689 			return i_blocks  << (inode->i_blkbits - 9);
4690 		} else {
4691 			return i_blocks;
4692 		}
4693 	} else {
4694 		return le32_to_cpu(raw_inode->i_blocks_lo);
4695 	}
4696 }
4697 
4698 static inline int ext4_iget_extra_inode(struct inode *inode,
4699 					 struct ext4_inode *raw_inode,
4700 					 struct ext4_inode_info *ei)
4701 {
4702 	__le32 *magic = (void *)raw_inode +
4703 			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4704 
4705 	if (EXT4_INODE_HAS_XATTR_SPACE(inode)  &&
4706 	    *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4707 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4708 		return ext4_find_inline_data_nolock(inode);
4709 	} else
4710 		EXT4_I(inode)->i_inline_off = 0;
4711 	return 0;
4712 }
4713 
4714 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4715 {
4716 	if (!ext4_has_feature_project(inode->i_sb))
4717 		return -EOPNOTSUPP;
4718 	*projid = EXT4_I(inode)->i_projid;
4719 	return 0;
4720 }
4721 
4722 /*
4723  * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4724  * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4725  * set.
4726  */
4727 static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4728 {
4729 	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4730 		inode_set_iversion_raw(inode, val);
4731 	else
4732 		inode_set_iversion_queried(inode, val);
4733 }
4734 
4735 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4736 			  ext4_iget_flags flags, const char *function,
4737 			  unsigned int line)
4738 {
4739 	struct ext4_iloc iloc;
4740 	struct ext4_inode *raw_inode;
4741 	struct ext4_inode_info *ei;
4742 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4743 	struct inode *inode;
4744 	journal_t *journal = EXT4_SB(sb)->s_journal;
4745 	long ret;
4746 	loff_t size;
4747 	int block;
4748 	uid_t i_uid;
4749 	gid_t i_gid;
4750 	projid_t i_projid;
4751 
4752 	if ((!(flags & EXT4_IGET_SPECIAL) &&
4753 	     ((ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) ||
4754 	      ino == le32_to_cpu(es->s_usr_quota_inum) ||
4755 	      ino == le32_to_cpu(es->s_grp_quota_inum) ||
4756 	      ino == le32_to_cpu(es->s_prj_quota_inum) ||
4757 	      ino == le32_to_cpu(es->s_orphan_file_inum))) ||
4758 	    (ino < EXT4_ROOT_INO) ||
4759 	    (ino > le32_to_cpu(es->s_inodes_count))) {
4760 		if (flags & EXT4_IGET_HANDLE)
4761 			return ERR_PTR(-ESTALE);
4762 		__ext4_error(sb, function, line, false, EFSCORRUPTED, 0,
4763 			     "inode #%lu: comm %s: iget: illegal inode #",
4764 			     ino, current->comm);
4765 		return ERR_PTR(-EFSCORRUPTED);
4766 	}
4767 
4768 	inode = iget_locked(sb, ino);
4769 	if (!inode)
4770 		return ERR_PTR(-ENOMEM);
4771 	if (!(inode->i_state & I_NEW))
4772 		return inode;
4773 
4774 	ei = EXT4_I(inode);
4775 	iloc.bh = NULL;
4776 
4777 	ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
4778 	if (ret < 0)
4779 		goto bad_inode;
4780 	raw_inode = ext4_raw_inode(&iloc);
4781 
4782 	if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) {
4783 		ext4_error_inode(inode, function, line, 0,
4784 				 "iget: root inode unallocated");
4785 		ret = -EFSCORRUPTED;
4786 		goto bad_inode;
4787 	}
4788 
4789 	if ((flags & EXT4_IGET_HANDLE) &&
4790 	    (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4791 		ret = -ESTALE;
4792 		goto bad_inode;
4793 	}
4794 
4795 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4796 		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4797 		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4798 			EXT4_INODE_SIZE(inode->i_sb) ||
4799 		    (ei->i_extra_isize & 3)) {
4800 			ext4_error_inode(inode, function, line, 0,
4801 					 "iget: bad extra_isize %u "
4802 					 "(inode size %u)",
4803 					 ei->i_extra_isize,
4804 					 EXT4_INODE_SIZE(inode->i_sb));
4805 			ret = -EFSCORRUPTED;
4806 			goto bad_inode;
4807 		}
4808 	} else
4809 		ei->i_extra_isize = 0;
4810 
4811 	/* Precompute checksum seed for inode metadata */
4812 	if (ext4_has_metadata_csum(sb)) {
4813 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4814 		__u32 csum;
4815 		__le32 inum = cpu_to_le32(inode->i_ino);
4816 		__le32 gen = raw_inode->i_generation;
4817 		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4818 				   sizeof(inum));
4819 		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4820 					      sizeof(gen));
4821 	}
4822 
4823 	if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4824 	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
4825 	     (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
4826 		ext4_error_inode_err(inode, function, line, 0,
4827 				EFSBADCRC, "iget: checksum invalid");
4828 		ret = -EFSBADCRC;
4829 		goto bad_inode;
4830 	}
4831 
4832 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4833 	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4834 	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4835 	if (ext4_has_feature_project(sb) &&
4836 	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4837 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4838 		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4839 	else
4840 		i_projid = EXT4_DEF_PROJID;
4841 
4842 	if (!(test_opt(inode->i_sb, NO_UID32))) {
4843 		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4844 		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4845 	}
4846 	i_uid_write(inode, i_uid);
4847 	i_gid_write(inode, i_gid);
4848 	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4849 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4850 
4851 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
4852 	ei->i_inline_off = 0;
4853 	ei->i_dir_start_lookup = 0;
4854 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4855 	/* We now have enough fields to check if the inode was active or not.
4856 	 * This is needed because nfsd might try to access dead inodes
4857 	 * the test is that same one that e2fsck uses
4858 	 * NeilBrown 1999oct15
4859 	 */
4860 	if (inode->i_nlink == 0) {
4861 		if ((inode->i_mode == 0 ||
4862 		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4863 		    ino != EXT4_BOOT_LOADER_INO) {
4864 			/* this inode is deleted */
4865 			ret = -ESTALE;
4866 			goto bad_inode;
4867 		}
4868 		/* The only unlinked inodes we let through here have
4869 		 * valid i_mode and are being read by the orphan
4870 		 * recovery code: that's fine, we're about to complete
4871 		 * the process of deleting those.
4872 		 * OR it is the EXT4_BOOT_LOADER_INO which is
4873 		 * not initialized on a new filesystem. */
4874 	}
4875 	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4876 	ext4_set_inode_flags(inode, true);
4877 	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4878 	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4879 	if (ext4_has_feature_64bit(sb))
4880 		ei->i_file_acl |=
4881 			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4882 	inode->i_size = ext4_isize(sb, raw_inode);
4883 	if ((size = i_size_read(inode)) < 0) {
4884 		ext4_error_inode(inode, function, line, 0,
4885 				 "iget: bad i_size value: %lld", size);
4886 		ret = -EFSCORRUPTED;
4887 		goto bad_inode;
4888 	}
4889 	/*
4890 	 * If dir_index is not enabled but there's dir with INDEX flag set,
4891 	 * we'd normally treat htree data as empty space. But with metadata
4892 	 * checksumming that corrupts checksums so forbid that.
4893 	 */
4894 	if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4895 	    ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4896 		ext4_error_inode(inode, function, line, 0,
4897 			 "iget: Dir with htree data on filesystem without dir_index feature.");
4898 		ret = -EFSCORRUPTED;
4899 		goto bad_inode;
4900 	}
4901 	ei->i_disksize = inode->i_size;
4902 #ifdef CONFIG_QUOTA
4903 	ei->i_reserved_quota = 0;
4904 #endif
4905 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4906 	ei->i_block_group = iloc.block_group;
4907 	ei->i_last_alloc_group = ~0;
4908 	/*
4909 	 * NOTE! The in-memory inode i_data array is in little-endian order
4910 	 * even on big-endian machines: we do NOT byteswap the block numbers!
4911 	 */
4912 	for (block = 0; block < EXT4_N_BLOCKS; block++)
4913 		ei->i_data[block] = raw_inode->i_block[block];
4914 	INIT_LIST_HEAD(&ei->i_orphan);
4915 	ext4_fc_init_inode(&ei->vfs_inode);
4916 
4917 	/*
4918 	 * Set transaction id's of transactions that have to be committed
4919 	 * to finish f[data]sync. We set them to currently running transaction
4920 	 * as we cannot be sure that the inode or some of its metadata isn't
4921 	 * part of the transaction - the inode could have been reclaimed and
4922 	 * now it is reread from disk.
4923 	 */
4924 	if (journal) {
4925 		transaction_t *transaction;
4926 		tid_t tid;
4927 
4928 		read_lock(&journal->j_state_lock);
4929 		if (journal->j_running_transaction)
4930 			transaction = journal->j_running_transaction;
4931 		else
4932 			transaction = journal->j_committing_transaction;
4933 		if (transaction)
4934 			tid = transaction->t_tid;
4935 		else
4936 			tid = journal->j_commit_sequence;
4937 		read_unlock(&journal->j_state_lock);
4938 		ei->i_sync_tid = tid;
4939 		ei->i_datasync_tid = tid;
4940 	}
4941 
4942 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4943 		if (ei->i_extra_isize == 0) {
4944 			/* The extra space is currently unused. Use it. */
4945 			BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4946 			ei->i_extra_isize = sizeof(struct ext4_inode) -
4947 					    EXT4_GOOD_OLD_INODE_SIZE;
4948 		} else {
4949 			ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4950 			if (ret)
4951 				goto bad_inode;
4952 		}
4953 	}
4954 
4955 	EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4956 	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4957 	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4958 	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4959 
4960 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4961 		u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4962 
4963 		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4964 			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4965 				ivers |=
4966 		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4967 		}
4968 		ext4_inode_set_iversion_queried(inode, ivers);
4969 	}
4970 
4971 	ret = 0;
4972 	if (ei->i_file_acl &&
4973 	    !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4974 		ext4_error_inode(inode, function, line, 0,
4975 				 "iget: bad extended attribute block %llu",
4976 				 ei->i_file_acl);
4977 		ret = -EFSCORRUPTED;
4978 		goto bad_inode;
4979 	} else if (!ext4_has_inline_data(inode)) {
4980 		/* validate the block references in the inode */
4981 		if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4982 			(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4983 			(S_ISLNK(inode->i_mode) &&
4984 			!ext4_inode_is_fast_symlink(inode)))) {
4985 			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4986 				ret = ext4_ext_check_inode(inode);
4987 			else
4988 				ret = ext4_ind_check_inode(inode);
4989 		}
4990 	}
4991 	if (ret)
4992 		goto bad_inode;
4993 
4994 	if (S_ISREG(inode->i_mode)) {
4995 		inode->i_op = &ext4_file_inode_operations;
4996 		inode->i_fop = &ext4_file_operations;
4997 		ext4_set_aops(inode);
4998 	} else if (S_ISDIR(inode->i_mode)) {
4999 		inode->i_op = &ext4_dir_inode_operations;
5000 		inode->i_fop = &ext4_dir_operations;
5001 	} else if (S_ISLNK(inode->i_mode)) {
5002 		/* VFS does not allow setting these so must be corruption */
5003 		if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
5004 			ext4_error_inode(inode, function, line, 0,
5005 					 "iget: immutable or append flags "
5006 					 "not allowed on symlinks");
5007 			ret = -EFSCORRUPTED;
5008 			goto bad_inode;
5009 		}
5010 		if (IS_ENCRYPTED(inode)) {
5011 			inode->i_op = &ext4_encrypted_symlink_inode_operations;
5012 		} else if (ext4_inode_is_fast_symlink(inode)) {
5013 			inode->i_link = (char *)ei->i_data;
5014 			inode->i_op = &ext4_fast_symlink_inode_operations;
5015 			nd_terminate_link(ei->i_data, inode->i_size,
5016 				sizeof(ei->i_data) - 1);
5017 		} else {
5018 			inode->i_op = &ext4_symlink_inode_operations;
5019 		}
5020 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
5021 	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
5022 		inode->i_op = &ext4_special_inode_operations;
5023 		if (raw_inode->i_block[0])
5024 			init_special_inode(inode, inode->i_mode,
5025 			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
5026 		else
5027 			init_special_inode(inode, inode->i_mode,
5028 			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
5029 	} else if (ino == EXT4_BOOT_LOADER_INO) {
5030 		make_bad_inode(inode);
5031 	} else {
5032 		ret = -EFSCORRUPTED;
5033 		ext4_error_inode(inode, function, line, 0,
5034 				 "iget: bogus i_mode (%o)", inode->i_mode);
5035 		goto bad_inode;
5036 	}
5037 	if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb))
5038 		ext4_error_inode(inode, function, line, 0,
5039 				 "casefold flag without casefold feature");
5040 	brelse(iloc.bh);
5041 
5042 	unlock_new_inode(inode);
5043 	return inode;
5044 
5045 bad_inode:
5046 	brelse(iloc.bh);
5047 	iget_failed(inode);
5048 	return ERR_PTR(ret);
5049 }
5050 
5051 static void __ext4_update_other_inode_time(struct super_block *sb,
5052 					   unsigned long orig_ino,
5053 					   unsigned long ino,
5054 					   struct ext4_inode *raw_inode)
5055 {
5056 	struct inode *inode;
5057 
5058 	inode = find_inode_by_ino_rcu(sb, ino);
5059 	if (!inode)
5060 		return;
5061 
5062 	if (!inode_is_dirtytime_only(inode))
5063 		return;
5064 
5065 	spin_lock(&inode->i_lock);
5066 	if (inode_is_dirtytime_only(inode)) {
5067 		struct ext4_inode_info	*ei = EXT4_I(inode);
5068 
5069 		inode->i_state &= ~I_DIRTY_TIME;
5070 		spin_unlock(&inode->i_lock);
5071 
5072 		spin_lock(&ei->i_raw_lock);
5073 		EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5074 		EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5075 		EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5076 		ext4_inode_csum_set(inode, raw_inode, ei);
5077 		spin_unlock(&ei->i_raw_lock);
5078 		trace_ext4_other_inode_update_time(inode, orig_ino);
5079 		return;
5080 	}
5081 	spin_unlock(&inode->i_lock);
5082 }
5083 
5084 /*
5085  * Opportunistically update the other time fields for other inodes in
5086  * the same inode table block.
5087  */
5088 static void ext4_update_other_inodes_time(struct super_block *sb,
5089 					  unsigned long orig_ino, char *buf)
5090 {
5091 	unsigned long ino;
5092 	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
5093 	int inode_size = EXT4_INODE_SIZE(sb);
5094 
5095 	/*
5096 	 * Calculate the first inode in the inode table block.  Inode
5097 	 * numbers are one-based.  That is, the first inode in a block
5098 	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
5099 	 */
5100 	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
5101 	rcu_read_lock();
5102 	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
5103 		if (ino == orig_ino)
5104 			continue;
5105 		__ext4_update_other_inode_time(sb, orig_ino, ino,
5106 					       (struct ext4_inode *)buf);
5107 	}
5108 	rcu_read_unlock();
5109 }
5110 
5111 /*
5112  * Post the struct inode info into an on-disk inode location in the
5113  * buffer-cache.  This gobbles the caller's reference to the
5114  * buffer_head in the inode location struct.
5115  *
5116  * The caller must have write access to iloc->bh.
5117  */
5118 static int ext4_do_update_inode(handle_t *handle,
5119 				struct inode *inode,
5120 				struct ext4_iloc *iloc)
5121 {
5122 	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5123 	struct ext4_inode_info *ei = EXT4_I(inode);
5124 	struct buffer_head *bh = iloc->bh;
5125 	struct super_block *sb = inode->i_sb;
5126 	int err;
5127 	int need_datasync = 0, set_large_file = 0;
5128 
5129 	spin_lock(&ei->i_raw_lock);
5130 
5131 	/*
5132 	 * For fields not tracked in the in-memory inode, initialise them
5133 	 * to zero for new inodes.
5134 	 */
5135 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5136 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5137 
5138 	if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode))
5139 		need_datasync = 1;
5140 	if (ei->i_disksize > 0x7fffffffULL) {
5141 		if (!ext4_has_feature_large_file(sb) ||
5142 		    EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV))
5143 			set_large_file = 1;
5144 	}
5145 
5146 	err = ext4_fill_raw_inode(inode, raw_inode);
5147 	spin_unlock(&ei->i_raw_lock);
5148 	if (err) {
5149 		EXT4_ERROR_INODE(inode, "corrupted inode contents");
5150 		goto out_brelse;
5151 	}
5152 
5153 	if (inode->i_sb->s_flags & SB_LAZYTIME)
5154 		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5155 					      bh->b_data);
5156 
5157 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5158 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5159 	if (err)
5160 		goto out_error;
5161 	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5162 	if (set_large_file) {
5163 		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5164 		err = ext4_journal_get_write_access(handle, sb,
5165 						    EXT4_SB(sb)->s_sbh,
5166 						    EXT4_JTR_NONE);
5167 		if (err)
5168 			goto out_error;
5169 		lock_buffer(EXT4_SB(sb)->s_sbh);
5170 		ext4_set_feature_large_file(sb);
5171 		ext4_superblock_csum_set(sb);
5172 		unlock_buffer(EXT4_SB(sb)->s_sbh);
5173 		ext4_handle_sync(handle);
5174 		err = ext4_handle_dirty_metadata(handle, NULL,
5175 						 EXT4_SB(sb)->s_sbh);
5176 	}
5177 	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5178 out_error:
5179 	ext4_std_error(inode->i_sb, err);
5180 out_brelse:
5181 	brelse(bh);
5182 	return err;
5183 }
5184 
5185 /*
5186  * ext4_write_inode()
5187  *
5188  * We are called from a few places:
5189  *
5190  * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5191  *   Here, there will be no transaction running. We wait for any running
5192  *   transaction to commit.
5193  *
5194  * - Within flush work (sys_sync(), kupdate and such).
5195  *   We wait on commit, if told to.
5196  *
5197  * - Within iput_final() -> write_inode_now()
5198  *   We wait on commit, if told to.
5199  *
5200  * In all cases it is actually safe for us to return without doing anything,
5201  * because the inode has been copied into a raw inode buffer in
5202  * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5203  * writeback.
5204  *
5205  * Note that we are absolutely dependent upon all inode dirtiers doing the
5206  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5207  * which we are interested.
5208  *
5209  * It would be a bug for them to not do this.  The code:
5210  *
5211  *	mark_inode_dirty(inode)
5212  *	stuff();
5213  *	inode->i_size = expr;
5214  *
5215  * is in error because write_inode() could occur while `stuff()' is running,
5216  * and the new i_size will be lost.  Plus the inode will no longer be on the
5217  * superblock's dirty inode list.
5218  */
5219 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5220 {
5221 	int err;
5222 
5223 	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC) ||
5224 	    sb_rdonly(inode->i_sb))
5225 		return 0;
5226 
5227 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5228 		return -EIO;
5229 
5230 	if (EXT4_SB(inode->i_sb)->s_journal) {
5231 		if (ext4_journal_current_handle()) {
5232 			ext4_debug("called recursively, non-PF_MEMALLOC!\n");
5233 			dump_stack();
5234 			return -EIO;
5235 		}
5236 
5237 		/*
5238 		 * No need to force transaction in WB_SYNC_NONE mode. Also
5239 		 * ext4_sync_fs() will force the commit after everything is
5240 		 * written.
5241 		 */
5242 		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5243 			return 0;
5244 
5245 		err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
5246 						EXT4_I(inode)->i_sync_tid);
5247 	} else {
5248 		struct ext4_iloc iloc;
5249 
5250 		err = __ext4_get_inode_loc_noinmem(inode, &iloc);
5251 		if (err)
5252 			return err;
5253 		/*
5254 		 * sync(2) will flush the whole buffer cache. No need to do
5255 		 * it here separately for each inode.
5256 		 */
5257 		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5258 			sync_dirty_buffer(iloc.bh);
5259 		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5260 			ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5261 					       "IO error syncing inode");
5262 			err = -EIO;
5263 		}
5264 		brelse(iloc.bh);
5265 	}
5266 	return err;
5267 }
5268 
5269 /*
5270  * In data=journal mode ext4_journalled_invalidate_folio() may fail to invalidate
5271  * buffers that are attached to a folio straddling i_size and are undergoing
5272  * commit. In that case we have to wait for commit to finish and try again.
5273  */
5274 static void ext4_wait_for_tail_page_commit(struct inode *inode)
5275 {
5276 	unsigned offset;
5277 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5278 	tid_t commit_tid = 0;
5279 	int ret;
5280 
5281 	offset = inode->i_size & (PAGE_SIZE - 1);
5282 	/*
5283 	 * If the folio is fully truncated, we don't need to wait for any commit
5284 	 * (and we even should not as __ext4_journalled_invalidate_folio() may
5285 	 * strip all buffers from the folio but keep the folio dirty which can then
5286 	 * confuse e.g. concurrent ext4_writepage() seeing dirty folio without
5287 	 * buffers). Also we don't need to wait for any commit if all buffers in
5288 	 * the folio remain valid. This is most beneficial for the common case of
5289 	 * blocksize == PAGESIZE.
5290 	 */
5291 	if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5292 		return;
5293 	while (1) {
5294 		struct folio *folio = filemap_lock_folio(inode->i_mapping,
5295 				      inode->i_size >> PAGE_SHIFT);
5296 		if (!folio)
5297 			return;
5298 		ret = __ext4_journalled_invalidate_folio(folio, offset,
5299 						folio_size(folio) - offset);
5300 		folio_unlock(folio);
5301 		folio_put(folio);
5302 		if (ret != -EBUSY)
5303 			return;
5304 		commit_tid = 0;
5305 		read_lock(&journal->j_state_lock);
5306 		if (journal->j_committing_transaction)
5307 			commit_tid = journal->j_committing_transaction->t_tid;
5308 		read_unlock(&journal->j_state_lock);
5309 		if (commit_tid)
5310 			jbd2_log_wait_commit(journal, commit_tid);
5311 	}
5312 }
5313 
5314 /*
5315  * ext4_setattr()
5316  *
5317  * Called from notify_change.
5318  *
5319  * We want to trap VFS attempts to truncate the file as soon as
5320  * possible.  In particular, we want to make sure that when the VFS
5321  * shrinks i_size, we put the inode on the orphan list and modify
5322  * i_disksize immediately, so that during the subsequent flushing of
5323  * dirty pages and freeing of disk blocks, we can guarantee that any
5324  * commit will leave the blocks being flushed in an unused state on
5325  * disk.  (On recovery, the inode will get truncated and the blocks will
5326  * be freed, so we have a strong guarantee that no future commit will
5327  * leave these blocks visible to the user.)
5328  *
5329  * Another thing we have to assure is that if we are in ordered mode
5330  * and inode is still attached to the committing transaction, we must
5331  * we start writeout of all the dirty pages which are being truncated.
5332  * This way we are sure that all the data written in the previous
5333  * transaction are already on disk (truncate waits for pages under
5334  * writeback).
5335  *
5336  * Called with inode->i_rwsem down.
5337  */
5338 int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
5339 		 struct iattr *attr)
5340 {
5341 	struct inode *inode = d_inode(dentry);
5342 	int error, rc = 0;
5343 	int orphan = 0;
5344 	const unsigned int ia_valid = attr->ia_valid;
5345 
5346 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5347 		return -EIO;
5348 
5349 	if (unlikely(IS_IMMUTABLE(inode)))
5350 		return -EPERM;
5351 
5352 	if (unlikely(IS_APPEND(inode) &&
5353 		     (ia_valid & (ATTR_MODE | ATTR_UID |
5354 				  ATTR_GID | ATTR_TIMES_SET))))
5355 		return -EPERM;
5356 
5357 	error = setattr_prepare(mnt_userns, dentry, attr);
5358 	if (error)
5359 		return error;
5360 
5361 	error = fscrypt_prepare_setattr(dentry, attr);
5362 	if (error)
5363 		return error;
5364 
5365 	error = fsverity_prepare_setattr(dentry, attr);
5366 	if (error)
5367 		return error;
5368 
5369 	if (is_quota_modification(mnt_userns, inode, attr)) {
5370 		error = dquot_initialize(inode);
5371 		if (error)
5372 			return error;
5373 	}
5374 
5375 	if (i_uid_needs_update(mnt_userns, attr, inode) ||
5376 	    i_gid_needs_update(mnt_userns, attr, inode)) {
5377 		handle_t *handle;
5378 
5379 		/* (user+group)*(old+new) structure, inode write (sb,
5380 		 * inode block, ? - but truncate inode update has it) */
5381 		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5382 			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5383 			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5384 		if (IS_ERR(handle)) {
5385 			error = PTR_ERR(handle);
5386 			goto err_out;
5387 		}
5388 
5389 		/* dquot_transfer() calls back ext4_get_inode_usage() which
5390 		 * counts xattr inode references.
5391 		 */
5392 		down_read(&EXT4_I(inode)->xattr_sem);
5393 		error = dquot_transfer(mnt_userns, inode, attr);
5394 		up_read(&EXT4_I(inode)->xattr_sem);
5395 
5396 		if (error) {
5397 			ext4_journal_stop(handle);
5398 			return error;
5399 		}
5400 		/* Update corresponding info in inode so that everything is in
5401 		 * one transaction */
5402 		i_uid_update(mnt_userns, attr, inode);
5403 		i_gid_update(mnt_userns, attr, inode);
5404 		error = ext4_mark_inode_dirty(handle, inode);
5405 		ext4_journal_stop(handle);
5406 		if (unlikely(error)) {
5407 			return error;
5408 		}
5409 	}
5410 
5411 	if (attr->ia_valid & ATTR_SIZE) {
5412 		handle_t *handle;
5413 		loff_t oldsize = inode->i_size;
5414 		loff_t old_disksize;
5415 		int shrink = (attr->ia_size < inode->i_size);
5416 
5417 		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5418 			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5419 
5420 			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5421 				return -EFBIG;
5422 			}
5423 		}
5424 		if (!S_ISREG(inode->i_mode)) {
5425 			return -EINVAL;
5426 		}
5427 
5428 		if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
5429 			inode_inc_iversion(inode);
5430 
5431 		if (shrink) {
5432 			if (ext4_should_order_data(inode)) {
5433 				error = ext4_begin_ordered_truncate(inode,
5434 							    attr->ia_size);
5435 				if (error)
5436 					goto err_out;
5437 			}
5438 			/*
5439 			 * Blocks are going to be removed from the inode. Wait
5440 			 * for dio in flight.
5441 			 */
5442 			inode_dio_wait(inode);
5443 		}
5444 
5445 		filemap_invalidate_lock(inode->i_mapping);
5446 
5447 		rc = ext4_break_layouts(inode);
5448 		if (rc) {
5449 			filemap_invalidate_unlock(inode->i_mapping);
5450 			goto err_out;
5451 		}
5452 
5453 		if (attr->ia_size != inode->i_size) {
5454 			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5455 			if (IS_ERR(handle)) {
5456 				error = PTR_ERR(handle);
5457 				goto out_mmap_sem;
5458 			}
5459 			if (ext4_handle_valid(handle) && shrink) {
5460 				error = ext4_orphan_add(handle, inode);
5461 				orphan = 1;
5462 			}
5463 			/*
5464 			 * Update c/mtime on truncate up, ext4_truncate() will
5465 			 * update c/mtime in shrink case below
5466 			 */
5467 			if (!shrink) {
5468 				inode->i_mtime = current_time(inode);
5469 				inode->i_ctime = inode->i_mtime;
5470 			}
5471 
5472 			if (shrink)
5473 				ext4_fc_track_range(handle, inode,
5474 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5475 					inode->i_sb->s_blocksize_bits,
5476 					EXT_MAX_BLOCKS - 1);
5477 			else
5478 				ext4_fc_track_range(
5479 					handle, inode,
5480 					(oldsize > 0 ? oldsize - 1 : oldsize) >>
5481 					inode->i_sb->s_blocksize_bits,
5482 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5483 					inode->i_sb->s_blocksize_bits);
5484 
5485 			down_write(&EXT4_I(inode)->i_data_sem);
5486 			old_disksize = EXT4_I(inode)->i_disksize;
5487 			EXT4_I(inode)->i_disksize = attr->ia_size;
5488 			rc = ext4_mark_inode_dirty(handle, inode);
5489 			if (!error)
5490 				error = rc;
5491 			/*
5492 			 * We have to update i_size under i_data_sem together
5493 			 * with i_disksize to avoid races with writeback code
5494 			 * running ext4_wb_update_i_disksize().
5495 			 */
5496 			if (!error)
5497 				i_size_write(inode, attr->ia_size);
5498 			else
5499 				EXT4_I(inode)->i_disksize = old_disksize;
5500 			up_write(&EXT4_I(inode)->i_data_sem);
5501 			ext4_journal_stop(handle);
5502 			if (error)
5503 				goto out_mmap_sem;
5504 			if (!shrink) {
5505 				pagecache_isize_extended(inode, oldsize,
5506 							 inode->i_size);
5507 			} else if (ext4_should_journal_data(inode)) {
5508 				ext4_wait_for_tail_page_commit(inode);
5509 			}
5510 		}
5511 
5512 		/*
5513 		 * Truncate pagecache after we've waited for commit
5514 		 * in data=journal mode to make pages freeable.
5515 		 */
5516 		truncate_pagecache(inode, inode->i_size);
5517 		/*
5518 		 * Call ext4_truncate() even if i_size didn't change to
5519 		 * truncate possible preallocated blocks.
5520 		 */
5521 		if (attr->ia_size <= oldsize) {
5522 			rc = ext4_truncate(inode);
5523 			if (rc)
5524 				error = rc;
5525 		}
5526 out_mmap_sem:
5527 		filemap_invalidate_unlock(inode->i_mapping);
5528 	}
5529 
5530 	if (!error) {
5531 		setattr_copy(mnt_userns, inode, attr);
5532 		mark_inode_dirty(inode);
5533 	}
5534 
5535 	/*
5536 	 * If the call to ext4_truncate failed to get a transaction handle at
5537 	 * all, we need to clean up the in-core orphan list manually.
5538 	 */
5539 	if (orphan && inode->i_nlink)
5540 		ext4_orphan_del(NULL, inode);
5541 
5542 	if (!error && (ia_valid & ATTR_MODE))
5543 		rc = posix_acl_chmod(mnt_userns, inode, inode->i_mode);
5544 
5545 err_out:
5546 	if  (error)
5547 		ext4_std_error(inode->i_sb, error);
5548 	if (!error)
5549 		error = rc;
5550 	return error;
5551 }
5552 
5553 int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
5554 		 struct kstat *stat, u32 request_mask, unsigned int query_flags)
5555 {
5556 	struct inode *inode = d_inode(path->dentry);
5557 	struct ext4_inode *raw_inode;
5558 	struct ext4_inode_info *ei = EXT4_I(inode);
5559 	unsigned int flags;
5560 
5561 	if ((request_mask & STATX_BTIME) &&
5562 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5563 		stat->result_mask |= STATX_BTIME;
5564 		stat->btime.tv_sec = ei->i_crtime.tv_sec;
5565 		stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5566 	}
5567 
5568 	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5569 	if (flags & EXT4_APPEND_FL)
5570 		stat->attributes |= STATX_ATTR_APPEND;
5571 	if (flags & EXT4_COMPR_FL)
5572 		stat->attributes |= STATX_ATTR_COMPRESSED;
5573 	if (flags & EXT4_ENCRYPT_FL)
5574 		stat->attributes |= STATX_ATTR_ENCRYPTED;
5575 	if (flags & EXT4_IMMUTABLE_FL)
5576 		stat->attributes |= STATX_ATTR_IMMUTABLE;
5577 	if (flags & EXT4_NODUMP_FL)
5578 		stat->attributes |= STATX_ATTR_NODUMP;
5579 	if (flags & EXT4_VERITY_FL)
5580 		stat->attributes |= STATX_ATTR_VERITY;
5581 
5582 	stat->attributes_mask |= (STATX_ATTR_APPEND |
5583 				  STATX_ATTR_COMPRESSED |
5584 				  STATX_ATTR_ENCRYPTED |
5585 				  STATX_ATTR_IMMUTABLE |
5586 				  STATX_ATTR_NODUMP |
5587 				  STATX_ATTR_VERITY);
5588 
5589 	generic_fillattr(mnt_userns, inode, stat);
5590 	return 0;
5591 }
5592 
5593 int ext4_file_getattr(struct user_namespace *mnt_userns,
5594 		      const struct path *path, struct kstat *stat,
5595 		      u32 request_mask, unsigned int query_flags)
5596 {
5597 	struct inode *inode = d_inode(path->dentry);
5598 	u64 delalloc_blocks;
5599 
5600 	ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
5601 
5602 	/*
5603 	 * If there is inline data in the inode, the inode will normally not
5604 	 * have data blocks allocated (it may have an external xattr block).
5605 	 * Report at least one sector for such files, so tools like tar, rsync,
5606 	 * others don't incorrectly think the file is completely sparse.
5607 	 */
5608 	if (unlikely(ext4_has_inline_data(inode)))
5609 		stat->blocks += (stat->size + 511) >> 9;
5610 
5611 	/*
5612 	 * We can't update i_blocks if the block allocation is delayed
5613 	 * otherwise in the case of system crash before the real block
5614 	 * allocation is done, we will have i_blocks inconsistent with
5615 	 * on-disk file blocks.
5616 	 * We always keep i_blocks updated together with real
5617 	 * allocation. But to not confuse with user, stat
5618 	 * will return the blocks that include the delayed allocation
5619 	 * blocks for this file.
5620 	 */
5621 	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5622 				   EXT4_I(inode)->i_reserved_data_blocks);
5623 	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5624 	return 0;
5625 }
5626 
5627 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5628 				   int pextents)
5629 {
5630 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5631 		return ext4_ind_trans_blocks(inode, lblocks);
5632 	return ext4_ext_index_trans_blocks(inode, pextents);
5633 }
5634 
5635 /*
5636  * Account for index blocks, block groups bitmaps and block group
5637  * descriptor blocks if modify datablocks and index blocks
5638  * worse case, the indexs blocks spread over different block groups
5639  *
5640  * If datablocks are discontiguous, they are possible to spread over
5641  * different block groups too. If they are contiguous, with flexbg,
5642  * they could still across block group boundary.
5643  *
5644  * Also account for superblock, inode, quota and xattr blocks
5645  */
5646 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5647 				  int pextents)
5648 {
5649 	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5650 	int gdpblocks;
5651 	int idxblocks;
5652 	int ret = 0;
5653 
5654 	/*
5655 	 * How many index blocks need to touch to map @lblocks logical blocks
5656 	 * to @pextents physical extents?
5657 	 */
5658 	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5659 
5660 	ret = idxblocks;
5661 
5662 	/*
5663 	 * Now let's see how many group bitmaps and group descriptors need
5664 	 * to account
5665 	 */
5666 	groups = idxblocks + pextents;
5667 	gdpblocks = groups;
5668 	if (groups > ngroups)
5669 		groups = ngroups;
5670 	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5671 		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5672 
5673 	/* bitmaps and block group descriptor blocks */
5674 	ret += groups + gdpblocks;
5675 
5676 	/* Blocks for super block, inode, quota and xattr blocks */
5677 	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5678 
5679 	return ret;
5680 }
5681 
5682 /*
5683  * Calculate the total number of credits to reserve to fit
5684  * the modification of a single pages into a single transaction,
5685  * which may include multiple chunks of block allocations.
5686  *
5687  * This could be called via ext4_write_begin()
5688  *
5689  * We need to consider the worse case, when
5690  * one new block per extent.
5691  */
5692 int ext4_writepage_trans_blocks(struct inode *inode)
5693 {
5694 	int bpp = ext4_journal_blocks_per_page(inode);
5695 	int ret;
5696 
5697 	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5698 
5699 	/* Account for data blocks for journalled mode */
5700 	if (ext4_should_journal_data(inode))
5701 		ret += bpp;
5702 	return ret;
5703 }
5704 
5705 /*
5706  * Calculate the journal credits for a chunk of data modification.
5707  *
5708  * This is called from DIO, fallocate or whoever calling
5709  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5710  *
5711  * journal buffers for data blocks are not included here, as DIO
5712  * and fallocate do no need to journal data buffers.
5713  */
5714 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5715 {
5716 	return ext4_meta_trans_blocks(inode, nrblocks, 1);
5717 }
5718 
5719 /*
5720  * The caller must have previously called ext4_reserve_inode_write().
5721  * Give this, we know that the caller already has write access to iloc->bh.
5722  */
5723 int ext4_mark_iloc_dirty(handle_t *handle,
5724 			 struct inode *inode, struct ext4_iloc *iloc)
5725 {
5726 	int err = 0;
5727 
5728 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
5729 		put_bh(iloc->bh);
5730 		return -EIO;
5731 	}
5732 	ext4_fc_track_inode(handle, inode);
5733 
5734 	if (IS_I_VERSION(inode))
5735 		inode_inc_iversion(inode);
5736 
5737 	/* the do_update_inode consumes one bh->b_count */
5738 	get_bh(iloc->bh);
5739 
5740 	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5741 	err = ext4_do_update_inode(handle, inode, iloc);
5742 	put_bh(iloc->bh);
5743 	return err;
5744 }
5745 
5746 /*
5747  * On success, We end up with an outstanding reference count against
5748  * iloc->bh.  This _must_ be cleaned up later.
5749  */
5750 
5751 int
5752 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5753 			 struct ext4_iloc *iloc)
5754 {
5755 	int err;
5756 
5757 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
5758 		return -EIO;
5759 
5760 	err = ext4_get_inode_loc(inode, iloc);
5761 	if (!err) {
5762 		BUFFER_TRACE(iloc->bh, "get_write_access");
5763 		err = ext4_journal_get_write_access(handle, inode->i_sb,
5764 						    iloc->bh, EXT4_JTR_NONE);
5765 		if (err) {
5766 			brelse(iloc->bh);
5767 			iloc->bh = NULL;
5768 		}
5769 	}
5770 	ext4_std_error(inode->i_sb, err);
5771 	return err;
5772 }
5773 
5774 static int __ext4_expand_extra_isize(struct inode *inode,
5775 				     unsigned int new_extra_isize,
5776 				     struct ext4_iloc *iloc,
5777 				     handle_t *handle, int *no_expand)
5778 {
5779 	struct ext4_inode *raw_inode;
5780 	struct ext4_xattr_ibody_header *header;
5781 	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5782 	struct ext4_inode_info *ei = EXT4_I(inode);
5783 	int error;
5784 
5785 	/* this was checked at iget time, but double check for good measure */
5786 	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5787 	    (ei->i_extra_isize & 3)) {
5788 		EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5789 				 ei->i_extra_isize,
5790 				 EXT4_INODE_SIZE(inode->i_sb));
5791 		return -EFSCORRUPTED;
5792 	}
5793 	if ((new_extra_isize < ei->i_extra_isize) ||
5794 	    (new_extra_isize < 4) ||
5795 	    (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5796 		return -EINVAL;	/* Should never happen */
5797 
5798 	raw_inode = ext4_raw_inode(iloc);
5799 
5800 	header = IHDR(inode, raw_inode);
5801 
5802 	/* No extended attributes present */
5803 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5804 	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5805 		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5806 		       EXT4_I(inode)->i_extra_isize, 0,
5807 		       new_extra_isize - EXT4_I(inode)->i_extra_isize);
5808 		EXT4_I(inode)->i_extra_isize = new_extra_isize;
5809 		return 0;
5810 	}
5811 
5812 	/* try to expand with EAs present */
5813 	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5814 					   raw_inode, handle);
5815 	if (error) {
5816 		/*
5817 		 * Inode size expansion failed; don't try again
5818 		 */
5819 		*no_expand = 1;
5820 	}
5821 
5822 	return error;
5823 }
5824 
5825 /*
5826  * Expand an inode by new_extra_isize bytes.
5827  * Returns 0 on success or negative error number on failure.
5828  */
5829 static int ext4_try_to_expand_extra_isize(struct inode *inode,
5830 					  unsigned int new_extra_isize,
5831 					  struct ext4_iloc iloc,
5832 					  handle_t *handle)
5833 {
5834 	int no_expand;
5835 	int error;
5836 
5837 	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5838 		return -EOVERFLOW;
5839 
5840 	/*
5841 	 * In nojournal mode, we can immediately attempt to expand
5842 	 * the inode.  When journaled, we first need to obtain extra
5843 	 * buffer credits since we may write into the EA block
5844 	 * with this same handle. If journal_extend fails, then it will
5845 	 * only result in a minor loss of functionality for that inode.
5846 	 * If this is felt to be critical, then e2fsck should be run to
5847 	 * force a large enough s_min_extra_isize.
5848 	 */
5849 	if (ext4_journal_extend(handle,
5850 				EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5851 		return -ENOSPC;
5852 
5853 	if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5854 		return -EBUSY;
5855 
5856 	error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5857 					  handle, &no_expand);
5858 	ext4_write_unlock_xattr(inode, &no_expand);
5859 
5860 	return error;
5861 }
5862 
5863 int ext4_expand_extra_isize(struct inode *inode,
5864 			    unsigned int new_extra_isize,
5865 			    struct ext4_iloc *iloc)
5866 {
5867 	handle_t *handle;
5868 	int no_expand;
5869 	int error, rc;
5870 
5871 	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5872 		brelse(iloc->bh);
5873 		return -EOVERFLOW;
5874 	}
5875 
5876 	handle = ext4_journal_start(inode, EXT4_HT_INODE,
5877 				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5878 	if (IS_ERR(handle)) {
5879 		error = PTR_ERR(handle);
5880 		brelse(iloc->bh);
5881 		return error;
5882 	}
5883 
5884 	ext4_write_lock_xattr(inode, &no_expand);
5885 
5886 	BUFFER_TRACE(iloc->bh, "get_write_access");
5887 	error = ext4_journal_get_write_access(handle, inode->i_sb, iloc->bh,
5888 					      EXT4_JTR_NONE);
5889 	if (error) {
5890 		brelse(iloc->bh);
5891 		goto out_unlock;
5892 	}
5893 
5894 	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5895 					  handle, &no_expand);
5896 
5897 	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5898 	if (!error)
5899 		error = rc;
5900 
5901 out_unlock:
5902 	ext4_write_unlock_xattr(inode, &no_expand);
5903 	ext4_journal_stop(handle);
5904 	return error;
5905 }
5906 
5907 /*
5908  * What we do here is to mark the in-core inode as clean with respect to inode
5909  * dirtiness (it may still be data-dirty).
5910  * This means that the in-core inode may be reaped by prune_icache
5911  * without having to perform any I/O.  This is a very good thing,
5912  * because *any* task may call prune_icache - even ones which
5913  * have a transaction open against a different journal.
5914  *
5915  * Is this cheating?  Not really.  Sure, we haven't written the
5916  * inode out, but prune_icache isn't a user-visible syncing function.
5917  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5918  * we start and wait on commits.
5919  */
5920 int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5921 				const char *func, unsigned int line)
5922 {
5923 	struct ext4_iloc iloc;
5924 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5925 	int err;
5926 
5927 	might_sleep();
5928 	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5929 	err = ext4_reserve_inode_write(handle, inode, &iloc);
5930 	if (err)
5931 		goto out;
5932 
5933 	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5934 		ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5935 					       iloc, handle);
5936 
5937 	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5938 out:
5939 	if (unlikely(err))
5940 		ext4_error_inode_err(inode, func, line, 0, err,
5941 					"mark_inode_dirty error");
5942 	return err;
5943 }
5944 
5945 /*
5946  * ext4_dirty_inode() is called from __mark_inode_dirty()
5947  *
5948  * We're really interested in the case where a file is being extended.
5949  * i_size has been changed by generic_commit_write() and we thus need
5950  * to include the updated inode in the current transaction.
5951  *
5952  * Also, dquot_alloc_block() will always dirty the inode when blocks
5953  * are allocated to the file.
5954  *
5955  * If the inode is marked synchronous, we don't honour that here - doing
5956  * so would cause a commit on atime updates, which we don't bother doing.
5957  * We handle synchronous inodes at the highest possible level.
5958  */
5959 void ext4_dirty_inode(struct inode *inode, int flags)
5960 {
5961 	handle_t *handle;
5962 
5963 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5964 	if (IS_ERR(handle))
5965 		return;
5966 	ext4_mark_inode_dirty(handle, inode);
5967 	ext4_journal_stop(handle);
5968 }
5969 
5970 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5971 {
5972 	journal_t *journal;
5973 	handle_t *handle;
5974 	int err;
5975 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5976 
5977 	/*
5978 	 * We have to be very careful here: changing a data block's
5979 	 * journaling status dynamically is dangerous.  If we write a
5980 	 * data block to the journal, change the status and then delete
5981 	 * that block, we risk forgetting to revoke the old log record
5982 	 * from the journal and so a subsequent replay can corrupt data.
5983 	 * So, first we make sure that the journal is empty and that
5984 	 * nobody is changing anything.
5985 	 */
5986 
5987 	journal = EXT4_JOURNAL(inode);
5988 	if (!journal)
5989 		return 0;
5990 	if (is_journal_aborted(journal))
5991 		return -EROFS;
5992 
5993 	/* Wait for all existing dio workers */
5994 	inode_dio_wait(inode);
5995 
5996 	/*
5997 	 * Before flushing the journal and switching inode's aops, we have
5998 	 * to flush all dirty data the inode has. There can be outstanding
5999 	 * delayed allocations, there can be unwritten extents created by
6000 	 * fallocate or buffered writes in dioread_nolock mode covered by
6001 	 * dirty data which can be converted only after flushing the dirty
6002 	 * data (and journalled aops don't know how to handle these cases).
6003 	 */
6004 	if (val) {
6005 		filemap_invalidate_lock(inode->i_mapping);
6006 		err = filemap_write_and_wait(inode->i_mapping);
6007 		if (err < 0) {
6008 			filemap_invalidate_unlock(inode->i_mapping);
6009 			return err;
6010 		}
6011 	}
6012 
6013 	percpu_down_write(&sbi->s_writepages_rwsem);
6014 	jbd2_journal_lock_updates(journal);
6015 
6016 	/*
6017 	 * OK, there are no updates running now, and all cached data is
6018 	 * synced to disk.  We are now in a completely consistent state
6019 	 * which doesn't have anything in the journal, and we know that
6020 	 * no filesystem updates are running, so it is safe to modify
6021 	 * the inode's in-core data-journaling state flag now.
6022 	 */
6023 
6024 	if (val)
6025 		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6026 	else {
6027 		err = jbd2_journal_flush(journal, 0);
6028 		if (err < 0) {
6029 			jbd2_journal_unlock_updates(journal);
6030 			percpu_up_write(&sbi->s_writepages_rwsem);
6031 			return err;
6032 		}
6033 		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6034 	}
6035 	ext4_set_aops(inode);
6036 
6037 	jbd2_journal_unlock_updates(journal);
6038 	percpu_up_write(&sbi->s_writepages_rwsem);
6039 
6040 	if (val)
6041 		filemap_invalidate_unlock(inode->i_mapping);
6042 
6043 	/* Finally we can mark the inode as dirty. */
6044 
6045 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
6046 	if (IS_ERR(handle))
6047 		return PTR_ERR(handle);
6048 
6049 	ext4_fc_mark_ineligible(inode->i_sb,
6050 		EXT4_FC_REASON_JOURNAL_FLAG_CHANGE, handle);
6051 	err = ext4_mark_inode_dirty(handle, inode);
6052 	ext4_handle_sync(handle);
6053 	ext4_journal_stop(handle);
6054 	ext4_std_error(inode->i_sb, err);
6055 
6056 	return err;
6057 }
6058 
6059 static int ext4_bh_unmapped(handle_t *handle, struct inode *inode,
6060 			    struct buffer_head *bh)
6061 {
6062 	return !buffer_mapped(bh);
6063 }
6064 
6065 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6066 {
6067 	struct vm_area_struct *vma = vmf->vma;
6068 	struct page *page = vmf->page;
6069 	loff_t size;
6070 	unsigned long len;
6071 	int err;
6072 	vm_fault_t ret;
6073 	struct file *file = vma->vm_file;
6074 	struct inode *inode = file_inode(file);
6075 	struct address_space *mapping = inode->i_mapping;
6076 	handle_t *handle;
6077 	get_block_t *get_block;
6078 	int retries = 0;
6079 
6080 	if (unlikely(IS_IMMUTABLE(inode)))
6081 		return VM_FAULT_SIGBUS;
6082 
6083 	sb_start_pagefault(inode->i_sb);
6084 	file_update_time(vma->vm_file);
6085 
6086 	filemap_invalidate_lock_shared(mapping);
6087 
6088 	err = ext4_convert_inline_data(inode);
6089 	if (err)
6090 		goto out_ret;
6091 
6092 	/*
6093 	 * On data journalling we skip straight to the transaction handle:
6094 	 * there's no delalloc; page truncated will be checked later; the
6095 	 * early return w/ all buffers mapped (calculates size/len) can't
6096 	 * be used; and there's no dioread_nolock, so only ext4_get_block.
6097 	 */
6098 	if (ext4_should_journal_data(inode))
6099 		goto retry_alloc;
6100 
6101 	/* Delalloc case is easy... */
6102 	if (test_opt(inode->i_sb, DELALLOC) &&
6103 	    !ext4_nonda_switch(inode->i_sb)) {
6104 		do {
6105 			err = block_page_mkwrite(vma, vmf,
6106 						   ext4_da_get_block_prep);
6107 		} while (err == -ENOSPC &&
6108 		       ext4_should_retry_alloc(inode->i_sb, &retries));
6109 		goto out_ret;
6110 	}
6111 
6112 	lock_page(page);
6113 	size = i_size_read(inode);
6114 	/* Page got truncated from under us? */
6115 	if (page->mapping != mapping || page_offset(page) > size) {
6116 		unlock_page(page);
6117 		ret = VM_FAULT_NOPAGE;
6118 		goto out;
6119 	}
6120 
6121 	if (page->index == size >> PAGE_SHIFT)
6122 		len = size & ~PAGE_MASK;
6123 	else
6124 		len = PAGE_SIZE;
6125 	/*
6126 	 * Return if we have all the buffers mapped. This avoids the need to do
6127 	 * journal_start/journal_stop which can block and take a long time
6128 	 *
6129 	 * This cannot be done for data journalling, as we have to add the
6130 	 * inode to the transaction's list to writeprotect pages on commit.
6131 	 */
6132 	if (page_has_buffers(page)) {
6133 		if (!ext4_walk_page_buffers(NULL, inode, page_buffers(page),
6134 					    0, len, NULL,
6135 					    ext4_bh_unmapped)) {
6136 			/* Wait so that we don't change page under IO */
6137 			wait_for_stable_page(page);
6138 			ret = VM_FAULT_LOCKED;
6139 			goto out;
6140 		}
6141 	}
6142 	unlock_page(page);
6143 	/* OK, we need to fill the hole... */
6144 	if (ext4_should_dioread_nolock(inode))
6145 		get_block = ext4_get_block_unwritten;
6146 	else
6147 		get_block = ext4_get_block;
6148 retry_alloc:
6149 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6150 				    ext4_writepage_trans_blocks(inode));
6151 	if (IS_ERR(handle)) {
6152 		ret = VM_FAULT_SIGBUS;
6153 		goto out;
6154 	}
6155 	/*
6156 	 * Data journalling can't use block_page_mkwrite() because it
6157 	 * will set_buffer_dirty() before do_journal_get_write_access()
6158 	 * thus might hit warning messages for dirty metadata buffers.
6159 	 */
6160 	if (!ext4_should_journal_data(inode)) {
6161 		err = block_page_mkwrite(vma, vmf, get_block);
6162 	} else {
6163 		lock_page(page);
6164 		size = i_size_read(inode);
6165 		/* Page got truncated from under us? */
6166 		if (page->mapping != mapping || page_offset(page) > size) {
6167 			ret = VM_FAULT_NOPAGE;
6168 			goto out_error;
6169 		}
6170 
6171 		if (page->index == size >> PAGE_SHIFT)
6172 			len = size & ~PAGE_MASK;
6173 		else
6174 			len = PAGE_SIZE;
6175 
6176 		err = __block_write_begin(page, 0, len, ext4_get_block);
6177 		if (!err) {
6178 			ret = VM_FAULT_SIGBUS;
6179 			if (ext4_walk_page_buffers(handle, inode,
6180 					page_buffers(page), 0, len, NULL,
6181 					do_journal_get_write_access))
6182 				goto out_error;
6183 			if (ext4_walk_page_buffers(handle, inode,
6184 					page_buffers(page), 0, len, NULL,
6185 					write_end_fn))
6186 				goto out_error;
6187 			if (ext4_jbd2_inode_add_write(handle, inode,
6188 						      page_offset(page), len))
6189 				goto out_error;
6190 			ext4_set_inode_state(inode, EXT4_STATE_JDATA);
6191 		} else {
6192 			unlock_page(page);
6193 		}
6194 	}
6195 	ext4_journal_stop(handle);
6196 	if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6197 		goto retry_alloc;
6198 out_ret:
6199 	ret = block_page_mkwrite_return(err);
6200 out:
6201 	filemap_invalidate_unlock_shared(mapping);
6202 	sb_end_pagefault(inode->i_sb);
6203 	return ret;
6204 out_error:
6205 	unlock_page(page);
6206 	ext4_journal_stop(handle);
6207 	goto out;
6208 }
6209