xref: /linux/fs/ext4/inode.c (revision 2775df6e5e324be9dc375f7db2c8d3042df72bbf)
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 
ext4_inode_csum(struct inode * inode,struct ext4_inode * raw,struct ext4_inode_info * ei)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 
ext4_inode_csum_verify(struct inode * inode,struct ext4_inode * raw,struct ext4_inode_info * ei)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 
ext4_inode_csum_set(struct inode * inode,struct ext4_inode * raw,struct ext4_inode_info * ei)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 
ext4_begin_ordered_truncate(struct inode * inode,loff_t new_size)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_meta_trans_blocks(struct inode *inode, int lblocks,
140 				  int pextents);
141 
142 /*
143  * Test whether an inode is a fast symlink.
144  * A fast symlink has its symlink data stored in ext4_inode_info->i_data.
145  */
ext4_inode_is_fast_symlink(struct inode * inode)146 int ext4_inode_is_fast_symlink(struct inode *inode)
147 {
148 	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
149 		int ea_blocks = EXT4_I(inode)->i_file_acl ?
150 				EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
151 
152 		if (ext4_has_inline_data(inode))
153 			return 0;
154 
155 		return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
156 	}
157 	return S_ISLNK(inode->i_mode) && inode->i_size &&
158 	       (inode->i_size < EXT4_N_BLOCKS * 4);
159 }
160 
161 /*
162  * Called at the last iput() if i_nlink is zero.
163  */
ext4_evict_inode(struct inode * inode)164 void ext4_evict_inode(struct inode *inode)
165 {
166 	handle_t *handle;
167 	int err;
168 	/*
169 	 * Credits for final inode cleanup and freeing:
170 	 * sb + inode (ext4_orphan_del()), block bitmap, group descriptor
171 	 * (xattr block freeing), bitmap, group descriptor (inode freeing)
172 	 */
173 	int extra_credits = 6;
174 	struct ext4_xattr_inode_array *ea_inode_array = NULL;
175 	bool freeze_protected = false;
176 
177 	trace_ext4_evict_inode(inode);
178 
179 	if (EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)
180 		ext4_evict_ea_inode(inode);
181 	if (inode->i_nlink) {
182 		truncate_inode_pages_final(&inode->i_data);
183 
184 		goto no_delete;
185 	}
186 
187 	if (is_bad_inode(inode))
188 		goto no_delete;
189 	dquot_initialize(inode);
190 
191 	if (ext4_should_order_data(inode))
192 		ext4_begin_ordered_truncate(inode, 0);
193 	truncate_inode_pages_final(&inode->i_data);
194 
195 	/*
196 	 * For inodes with journalled data, transaction commit could have
197 	 * dirtied the inode. And for inodes with dioread_nolock, unwritten
198 	 * extents converting worker could merge extents and also have dirtied
199 	 * the inode. Flush worker is ignoring it because of I_FREEING flag but
200 	 * we still need to remove the inode from the writeback lists.
201 	 */
202 	if (!list_empty_careful(&inode->i_io_list))
203 		inode_io_list_del(inode);
204 
205 	/*
206 	 * Protect us against freezing - iput() caller didn't have to have any
207 	 * protection against it. When we are in a running transaction though,
208 	 * we are already protected against freezing and we cannot grab further
209 	 * protection due to lock ordering constraints.
210 	 */
211 	if (!ext4_journal_current_handle()) {
212 		sb_start_intwrite(inode->i_sb);
213 		freeze_protected = true;
214 	}
215 
216 	if (!IS_NOQUOTA(inode))
217 		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
218 
219 	/*
220 	 * Block bitmap, group descriptor, and inode are accounted in both
221 	 * ext4_blocks_for_truncate() and extra_credits. So subtract 3.
222 	 */
223 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
224 			 ext4_blocks_for_truncate(inode) + extra_credits - 3);
225 	if (IS_ERR(handle)) {
226 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
227 		/*
228 		 * If we're going to skip the normal cleanup, we still need to
229 		 * make sure that the in-core orphan linked list is properly
230 		 * cleaned up.
231 		 */
232 		ext4_orphan_del(NULL, inode);
233 		if (freeze_protected)
234 			sb_end_intwrite(inode->i_sb);
235 		goto no_delete;
236 	}
237 
238 	if (IS_SYNC(inode))
239 		ext4_handle_sync(handle);
240 
241 	/*
242 	 * Set inode->i_size to 0 before calling ext4_truncate(). We need
243 	 * special handling of symlinks here because i_size is used to
244 	 * determine whether ext4_inode_info->i_data contains symlink data or
245 	 * block mappings. Setting i_size to 0 will remove its fast symlink
246 	 * status. Erase i_data so that it becomes a valid empty block map.
247 	 */
248 	if (ext4_inode_is_fast_symlink(inode))
249 		memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
250 	inode->i_size = 0;
251 	err = ext4_mark_inode_dirty(handle, inode);
252 	if (err) {
253 		ext4_warning(inode->i_sb,
254 			     "couldn't mark inode dirty (err %d)", err);
255 		goto stop_handle;
256 	}
257 	if (inode->i_blocks) {
258 		err = ext4_truncate(inode);
259 		if (err) {
260 			ext4_error_err(inode->i_sb, -err,
261 				       "couldn't truncate inode %lu (err %d)",
262 				       inode->i_ino, err);
263 			goto stop_handle;
264 		}
265 	}
266 
267 	/* Remove xattr references. */
268 	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
269 				      extra_credits);
270 	if (err) {
271 		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
272 stop_handle:
273 		ext4_journal_stop(handle);
274 		ext4_orphan_del(NULL, inode);
275 		if (freeze_protected)
276 			sb_end_intwrite(inode->i_sb);
277 		ext4_xattr_inode_array_free(ea_inode_array);
278 		goto no_delete;
279 	}
280 
281 	/*
282 	 * Kill off the orphan record which ext4_truncate created.
283 	 * AKPM: I think this can be inside the above `if'.
284 	 * Note that ext4_orphan_del() has to be able to cope with the
285 	 * deletion of a non-existent orphan - this is because we don't
286 	 * know if ext4_truncate() actually created an orphan record.
287 	 * (Well, we could do this if we need to, but heck - it works)
288 	 */
289 	ext4_orphan_del(handle, inode);
290 	EXT4_I(inode)->i_dtime	= (__u32)ktime_get_real_seconds();
291 
292 	/*
293 	 * One subtle ordering requirement: if anything has gone wrong
294 	 * (transaction abort, IO errors, whatever), then we can still
295 	 * do these next steps (the fs will already have been marked as
296 	 * having errors), but we can't free the inode if the mark_dirty
297 	 * fails.
298 	 */
299 	if (ext4_mark_inode_dirty(handle, inode))
300 		/* If that failed, just do the required in-core inode clear. */
301 		ext4_clear_inode(inode);
302 	else
303 		ext4_free_inode(handle, inode);
304 	ext4_journal_stop(handle);
305 	if (freeze_protected)
306 		sb_end_intwrite(inode->i_sb);
307 	ext4_xattr_inode_array_free(ea_inode_array);
308 	return;
309 no_delete:
310 	/*
311 	 * Check out some where else accidentally dirty the evicting inode,
312 	 * which may probably cause inode use-after-free issues later.
313 	 */
314 	WARN_ON_ONCE(!list_empty_careful(&inode->i_io_list));
315 
316 	if (!list_empty(&EXT4_I(inode)->i_fc_list))
317 		ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL);
318 	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
319 }
320 
321 #ifdef CONFIG_QUOTA
ext4_get_reserved_space(struct inode * inode)322 qsize_t *ext4_get_reserved_space(struct inode *inode)
323 {
324 	return &EXT4_I(inode)->i_reserved_quota;
325 }
326 #endif
327 
328 /*
329  * Called with i_data_sem down, which is important since we can call
330  * ext4_discard_preallocations() from here.
331  */
ext4_da_update_reserve_space(struct inode * inode,int used,int quota_claim)332 void ext4_da_update_reserve_space(struct inode *inode,
333 					int used, int quota_claim)
334 {
335 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
336 	struct ext4_inode_info *ei = EXT4_I(inode);
337 
338 	spin_lock(&ei->i_block_reservation_lock);
339 	trace_ext4_da_update_reserve_space(inode, used, quota_claim);
340 	if (unlikely(used > ei->i_reserved_data_blocks)) {
341 		ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
342 			 "with only %d reserved data blocks",
343 			 __func__, inode->i_ino, used,
344 			 ei->i_reserved_data_blocks);
345 		WARN_ON(1);
346 		used = ei->i_reserved_data_blocks;
347 	}
348 
349 	/* Update per-inode reservations */
350 	ei->i_reserved_data_blocks -= used;
351 	percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
352 
353 	spin_unlock(&ei->i_block_reservation_lock);
354 
355 	/* Update quota subsystem for data blocks */
356 	if (quota_claim)
357 		dquot_claim_block(inode, EXT4_C2B(sbi, used));
358 	else {
359 		/*
360 		 * We did fallocate with an offset that is already delayed
361 		 * allocated. So on delayed allocated writeback we should
362 		 * not re-claim the quota for fallocated blocks.
363 		 */
364 		dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
365 	}
366 
367 	/*
368 	 * If we have done all the pending block allocations and if
369 	 * there aren't any writers on the inode, we can discard the
370 	 * inode's preallocations.
371 	 */
372 	if ((ei->i_reserved_data_blocks == 0) &&
373 	    !inode_is_open_for_write(inode))
374 		ext4_discard_preallocations(inode);
375 }
376 
__check_block_validity(struct inode * inode,const char * func,unsigned int line,struct ext4_map_blocks * map)377 static int __check_block_validity(struct inode *inode, const char *func,
378 				unsigned int line,
379 				struct ext4_map_blocks *map)
380 {
381 	if (ext4_has_feature_journal(inode->i_sb) &&
382 	    (inode->i_ino ==
383 	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
384 		return 0;
385 	if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
386 		ext4_error_inode(inode, func, line, map->m_pblk,
387 				 "lblock %lu mapped to illegal pblock %llu "
388 				 "(length %d)", (unsigned long) map->m_lblk,
389 				 map->m_pblk, map->m_len);
390 		return -EFSCORRUPTED;
391 	}
392 	return 0;
393 }
394 
ext4_issue_zeroout(struct inode * inode,ext4_lblk_t lblk,ext4_fsblk_t pblk,ext4_lblk_t len)395 int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
396 		       ext4_lblk_t len)
397 {
398 	int ret;
399 
400 	if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
401 		return fscrypt_zeroout_range(inode, lblk, pblk, len);
402 
403 	ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
404 	if (ret > 0)
405 		ret = 0;
406 
407 	return ret;
408 }
409 
410 #define check_block_validity(inode, map)	\
411 	__check_block_validity((inode), __func__, __LINE__, (map))
412 
413 #ifdef ES_AGGRESSIVE_TEST
ext4_map_blocks_es_recheck(handle_t * handle,struct inode * inode,struct ext4_map_blocks * es_map,struct ext4_map_blocks * map,int flags)414 static void ext4_map_blocks_es_recheck(handle_t *handle,
415 				       struct inode *inode,
416 				       struct ext4_map_blocks *es_map,
417 				       struct ext4_map_blocks *map,
418 				       int flags)
419 {
420 	int retval;
421 
422 	map->m_flags = 0;
423 	/*
424 	 * There is a race window that the result is not the same.
425 	 * e.g. xfstests #223 when dioread_nolock enables.  The reason
426 	 * is that we lookup a block mapping in extent status tree with
427 	 * out taking i_data_sem.  So at the time the unwritten extent
428 	 * could be converted.
429 	 */
430 	down_read(&EXT4_I(inode)->i_data_sem);
431 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
432 		retval = ext4_ext_map_blocks(handle, inode, map, 0);
433 	} else {
434 		retval = ext4_ind_map_blocks(handle, inode, map, 0);
435 	}
436 	up_read((&EXT4_I(inode)->i_data_sem));
437 
438 	/*
439 	 * We don't check m_len because extent will be collpased in status
440 	 * tree.  So the m_len might not equal.
441 	 */
442 	if (es_map->m_lblk != map->m_lblk ||
443 	    es_map->m_flags != map->m_flags ||
444 	    es_map->m_pblk != map->m_pblk) {
445 		printk("ES cache assertion failed for inode: %lu "
446 		       "es_cached ex [%d/%d/%llu/%x] != "
447 		       "found ex [%d/%d/%llu/%x] retval %d flags %x\n",
448 		       inode->i_ino, es_map->m_lblk, es_map->m_len,
449 		       es_map->m_pblk, es_map->m_flags, map->m_lblk,
450 		       map->m_len, map->m_pblk, map->m_flags,
451 		       retval, flags);
452 	}
453 }
454 #endif /* ES_AGGRESSIVE_TEST */
455 
ext4_map_query_blocks(handle_t * handle,struct inode * inode,struct ext4_map_blocks * map)456 static int ext4_map_query_blocks(handle_t *handle, struct inode *inode,
457 				 struct ext4_map_blocks *map)
458 {
459 	unsigned int status;
460 	int retval;
461 
462 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
463 		retval = ext4_ext_map_blocks(handle, inode, map, 0);
464 	else
465 		retval = ext4_ind_map_blocks(handle, inode, map, 0);
466 
467 	if (retval <= 0)
468 		return retval;
469 
470 	if (unlikely(retval != map->m_len)) {
471 		ext4_warning(inode->i_sb,
472 			     "ES len assertion failed for inode "
473 			     "%lu: retval %d != map->m_len %d",
474 			     inode->i_ino, retval, map->m_len);
475 		WARN_ON(1);
476 	}
477 
478 	status = map->m_flags & EXT4_MAP_UNWRITTEN ?
479 			EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
480 	ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
481 			      map->m_pblk, status);
482 	return retval;
483 }
484 
485 /*
486  * The ext4_map_blocks() function tries to look up the requested blocks,
487  * and returns if the blocks are already mapped.
488  *
489  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
490  * and store the allocated blocks in the result buffer head and mark it
491  * mapped.
492  *
493  * If file type is extents based, it will call ext4_ext_map_blocks(),
494  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
495  * based files
496  *
497  * On success, it returns the number of blocks being mapped or allocated.
498  * If flags doesn't contain EXT4_GET_BLOCKS_CREATE the blocks are
499  * pre-allocated and unwritten, the resulting @map is marked as unwritten.
500  * If the flags contain EXT4_GET_BLOCKS_CREATE, it will mark @map as mapped.
501  *
502  * It returns 0 if plain look up failed (blocks have not been allocated), in
503  * that case, @map is returned as unmapped but we still do fill map->m_len to
504  * indicate the length of a hole starting at map->m_lblk.
505  *
506  * It returns the error in case of allocation failure.
507  */
ext4_map_blocks(handle_t * handle,struct inode * inode,struct ext4_map_blocks * map,int flags)508 int ext4_map_blocks(handle_t *handle, struct inode *inode,
509 		    struct ext4_map_blocks *map, int flags)
510 {
511 	struct extent_status es;
512 	int retval;
513 	int ret = 0;
514 #ifdef ES_AGGRESSIVE_TEST
515 	struct ext4_map_blocks orig_map;
516 
517 	memcpy(&orig_map, map, sizeof(*map));
518 #endif
519 
520 	map->m_flags = 0;
521 	ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
522 		  flags, map->m_len, (unsigned long) map->m_lblk);
523 
524 	/*
525 	 * ext4_map_blocks returns an int, and m_len is an unsigned int
526 	 */
527 	if (unlikely(map->m_len > INT_MAX))
528 		map->m_len = INT_MAX;
529 
530 	/* We can handle the block number less than EXT_MAX_BLOCKS */
531 	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
532 		return -EFSCORRUPTED;
533 
534 	/* Lookup extent status tree firstly */
535 	if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
536 	    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
537 		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
538 			map->m_pblk = ext4_es_pblock(&es) +
539 					map->m_lblk - es.es_lblk;
540 			map->m_flags |= ext4_es_is_written(&es) ?
541 					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
542 			retval = es.es_len - (map->m_lblk - es.es_lblk);
543 			if (retval > map->m_len)
544 				retval = map->m_len;
545 			map->m_len = retval;
546 		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
547 			map->m_pblk = 0;
548 			map->m_flags |= ext4_es_is_delayed(&es) ?
549 					EXT4_MAP_DELAYED : 0;
550 			retval = es.es_len - (map->m_lblk - es.es_lblk);
551 			if (retval > map->m_len)
552 				retval = map->m_len;
553 			map->m_len = retval;
554 			retval = 0;
555 		} else {
556 			BUG();
557 		}
558 
559 		if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
560 			return retval;
561 #ifdef ES_AGGRESSIVE_TEST
562 		ext4_map_blocks_es_recheck(handle, inode, map,
563 					   &orig_map, flags);
564 #endif
565 		goto found;
566 	}
567 	/*
568 	 * In the query cache no-wait mode, nothing we can do more if we
569 	 * cannot find extent in the cache.
570 	 */
571 	if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
572 		return 0;
573 
574 	/*
575 	 * Try to see if we can get the block without requesting a new
576 	 * file system block.
577 	 */
578 	down_read(&EXT4_I(inode)->i_data_sem);
579 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
580 		retval = ext4_ext_map_blocks(handle, inode, map, 0);
581 	} else {
582 		retval = ext4_ind_map_blocks(handle, inode, map, 0);
583 	}
584 	if (retval > 0) {
585 		unsigned int status;
586 
587 		if (unlikely(retval != map->m_len)) {
588 			ext4_warning(inode->i_sb,
589 				     "ES len assertion failed for inode "
590 				     "%lu: retval %d != map->m_len %d",
591 				     inode->i_ino, retval, map->m_len);
592 			WARN_ON(1);
593 		}
594 
595 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
596 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
597 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
598 		    !(status & EXTENT_STATUS_WRITTEN) &&
599 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
600 				       map->m_lblk + map->m_len - 1))
601 			status |= EXTENT_STATUS_DELAYED;
602 		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
603 				      map->m_pblk, status);
604 	}
605 	up_read((&EXT4_I(inode)->i_data_sem));
606 
607 found:
608 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
609 		ret = check_block_validity(inode, map);
610 		if (ret != 0)
611 			return ret;
612 	}
613 
614 	/* If it is only a block(s) look up */
615 	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
616 		return retval;
617 
618 	/*
619 	 * Returns if the blocks have already allocated
620 	 *
621 	 * Note that if blocks have been preallocated
622 	 * ext4_ext_map_blocks() returns with buffer head unmapped
623 	 */
624 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
625 		/*
626 		 * If we need to convert extent to unwritten
627 		 * we continue and do the actual work in
628 		 * ext4_ext_map_blocks()
629 		 */
630 		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
631 			return retval;
632 
633 	/*
634 	 * Here we clear m_flags because after allocating an new extent,
635 	 * it will be set again.
636 	 */
637 	map->m_flags &= ~EXT4_MAP_FLAGS;
638 
639 	/*
640 	 * New blocks allocate and/or writing to unwritten extent
641 	 * will possibly result in updating i_data, so we take
642 	 * the write lock of i_data_sem, and call get_block()
643 	 * with create == 1 flag.
644 	 */
645 	down_write(&EXT4_I(inode)->i_data_sem);
646 
647 	/*
648 	 * We need to check for EXT4 here because migrate
649 	 * could have changed the inode type in between
650 	 */
651 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
652 		retval = ext4_ext_map_blocks(handle, inode, map, flags);
653 	} else {
654 		retval = ext4_ind_map_blocks(handle, inode, map, flags);
655 
656 		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
657 			/*
658 			 * We allocated new blocks which will result in
659 			 * i_data's format changing.  Force the migrate
660 			 * to fail by clearing migrate flags
661 			 */
662 			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
663 		}
664 	}
665 
666 	if (retval > 0) {
667 		unsigned int status;
668 
669 		if (unlikely(retval != map->m_len)) {
670 			ext4_warning(inode->i_sb,
671 				     "ES len assertion failed for inode "
672 				     "%lu: retval %d != map->m_len %d",
673 				     inode->i_ino, retval, map->m_len);
674 			WARN_ON(1);
675 		}
676 
677 		/*
678 		 * We have to zeroout blocks before inserting them into extent
679 		 * status tree. Otherwise someone could look them up there and
680 		 * use them before they are really zeroed. We also have to
681 		 * unmap metadata before zeroing as otherwise writeback can
682 		 * overwrite zeros with stale data from block device.
683 		 */
684 		if (flags & EXT4_GET_BLOCKS_ZERO &&
685 		    map->m_flags & EXT4_MAP_MAPPED &&
686 		    map->m_flags & EXT4_MAP_NEW) {
687 			ret = ext4_issue_zeroout(inode, map->m_lblk,
688 						 map->m_pblk, map->m_len);
689 			if (ret) {
690 				retval = ret;
691 				goto out_sem;
692 			}
693 		}
694 
695 		/*
696 		 * If the extent has been zeroed out, we don't need to update
697 		 * extent status tree.
698 		 */
699 		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
700 		    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
701 			if (ext4_es_is_written(&es))
702 				goto out_sem;
703 		}
704 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
705 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
706 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
707 		    !(status & EXTENT_STATUS_WRITTEN) &&
708 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
709 				       map->m_lblk + map->m_len - 1))
710 			status |= EXTENT_STATUS_DELAYED;
711 		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
712 				      map->m_pblk, status);
713 	}
714 
715 out_sem:
716 	up_write((&EXT4_I(inode)->i_data_sem));
717 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
718 		ret = check_block_validity(inode, map);
719 		if (ret != 0)
720 			return ret;
721 
722 		/*
723 		 * Inodes with freshly allocated blocks where contents will be
724 		 * visible after transaction commit must be on transaction's
725 		 * ordered data list.
726 		 */
727 		if (map->m_flags & EXT4_MAP_NEW &&
728 		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
729 		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
730 		    !ext4_is_quota_file(inode) &&
731 		    ext4_should_order_data(inode)) {
732 			loff_t start_byte =
733 				(loff_t)map->m_lblk << inode->i_blkbits;
734 			loff_t length = (loff_t)map->m_len << inode->i_blkbits;
735 
736 			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
737 				ret = ext4_jbd2_inode_add_wait(handle, inode,
738 						start_byte, length);
739 			else
740 				ret = ext4_jbd2_inode_add_write(handle, inode,
741 						start_byte, length);
742 			if (ret)
743 				return ret;
744 		}
745 	}
746 	if (retval > 0 && (map->m_flags & EXT4_MAP_UNWRITTEN ||
747 				map->m_flags & EXT4_MAP_MAPPED))
748 		ext4_fc_track_range(handle, inode, map->m_lblk,
749 					map->m_lblk + map->m_len - 1);
750 	if (retval < 0)
751 		ext_debug(inode, "failed with err %d\n", retval);
752 	return retval;
753 }
754 
755 /*
756  * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
757  * we have to be careful as someone else may be manipulating b_state as well.
758  */
ext4_update_bh_state(struct buffer_head * bh,unsigned long flags)759 static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
760 {
761 	unsigned long old_state;
762 	unsigned long new_state;
763 
764 	flags &= EXT4_MAP_FLAGS;
765 
766 	/* Dummy buffer_head? Set non-atomically. */
767 	if (!bh->b_page) {
768 		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
769 		return;
770 	}
771 	/*
772 	 * Someone else may be modifying b_state. Be careful! This is ugly but
773 	 * once we get rid of using bh as a container for mapping information
774 	 * to pass to / from get_block functions, this can go away.
775 	 */
776 	old_state = READ_ONCE(bh->b_state);
777 	do {
778 		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
779 	} while (unlikely(!try_cmpxchg(&bh->b_state, &old_state, new_state)));
780 }
781 
_ext4_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int flags)782 static int _ext4_get_block(struct inode *inode, sector_t iblock,
783 			   struct buffer_head *bh, int flags)
784 {
785 	struct ext4_map_blocks map;
786 	int ret = 0;
787 
788 	if (ext4_has_inline_data(inode))
789 		return -ERANGE;
790 
791 	map.m_lblk = iblock;
792 	map.m_len = bh->b_size >> inode->i_blkbits;
793 
794 	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
795 			      flags);
796 	if (ret > 0) {
797 		map_bh(bh, inode->i_sb, map.m_pblk);
798 		ext4_update_bh_state(bh, map.m_flags);
799 		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
800 		ret = 0;
801 	} else if (ret == 0) {
802 		/* hole case, need to fill in bh->b_size */
803 		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
804 	}
805 	return ret;
806 }
807 
ext4_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)808 int ext4_get_block(struct inode *inode, sector_t iblock,
809 		   struct buffer_head *bh, int create)
810 {
811 	return _ext4_get_block(inode, iblock, bh,
812 			       create ? EXT4_GET_BLOCKS_CREATE : 0);
813 }
814 
815 /*
816  * Get block function used when preparing for buffered write if we require
817  * creating an unwritten extent if blocks haven't been allocated.  The extent
818  * will be converted to written after the IO is complete.
819  */
ext4_get_block_unwritten(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)820 int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
821 			     struct buffer_head *bh_result, int create)
822 {
823 	int ret = 0;
824 
825 	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
826 		   inode->i_ino, create);
827 	ret = _ext4_get_block(inode, iblock, bh_result,
828 			       EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
829 
830 	/*
831 	 * If the buffer is marked unwritten, mark it as new to make sure it is
832 	 * zeroed out correctly in case of partial writes. Otherwise, there is
833 	 * a chance of stale data getting exposed.
834 	 */
835 	if (ret == 0 && buffer_unwritten(bh_result))
836 		set_buffer_new(bh_result);
837 
838 	return ret;
839 }
840 
841 /* Maximum number of blocks we map for direct IO at once. */
842 #define DIO_MAX_BLOCKS 4096
843 
844 /*
845  * `handle' can be NULL if create is zero
846  */
ext4_getblk(handle_t * handle,struct inode * inode,ext4_lblk_t block,int map_flags)847 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
848 				ext4_lblk_t block, int map_flags)
849 {
850 	struct ext4_map_blocks map;
851 	struct buffer_head *bh;
852 	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
853 	bool nowait = map_flags & EXT4_GET_BLOCKS_CACHED_NOWAIT;
854 	int err;
855 
856 	ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
857 		    || handle != NULL || create == 0);
858 	ASSERT(create == 0 || !nowait);
859 
860 	map.m_lblk = block;
861 	map.m_len = 1;
862 	err = ext4_map_blocks(handle, inode, &map, map_flags);
863 
864 	if (err == 0)
865 		return create ? ERR_PTR(-ENOSPC) : NULL;
866 	if (err < 0)
867 		return ERR_PTR(err);
868 
869 	if (nowait)
870 		return sb_find_get_block(inode->i_sb, map.m_pblk);
871 
872 	bh = sb_getblk(inode->i_sb, map.m_pblk);
873 	if (unlikely(!bh))
874 		return ERR_PTR(-ENOMEM);
875 	if (map.m_flags & EXT4_MAP_NEW) {
876 		ASSERT(create != 0);
877 		ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
878 			    || (handle != NULL));
879 
880 		/*
881 		 * Now that we do not always journal data, we should
882 		 * keep in mind whether this should always journal the
883 		 * new buffer as metadata.  For now, regular file
884 		 * writes use ext4_get_block instead, so it's not a
885 		 * problem.
886 		 */
887 		lock_buffer(bh);
888 		BUFFER_TRACE(bh, "call get_create_access");
889 		err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
890 						     EXT4_JTR_NONE);
891 		if (unlikely(err)) {
892 			unlock_buffer(bh);
893 			goto errout;
894 		}
895 		if (!buffer_uptodate(bh)) {
896 			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
897 			set_buffer_uptodate(bh);
898 		}
899 		unlock_buffer(bh);
900 		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
901 		err = ext4_handle_dirty_metadata(handle, inode, bh);
902 		if (unlikely(err))
903 			goto errout;
904 	} else
905 		BUFFER_TRACE(bh, "not a new buffer");
906 	return bh;
907 errout:
908 	brelse(bh);
909 	return ERR_PTR(err);
910 }
911 
ext4_bread(handle_t * handle,struct inode * inode,ext4_lblk_t block,int map_flags)912 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
913 			       ext4_lblk_t block, int map_flags)
914 {
915 	struct buffer_head *bh;
916 	int ret;
917 
918 	bh = ext4_getblk(handle, inode, block, map_flags);
919 	if (IS_ERR(bh))
920 		return bh;
921 	if (!bh || ext4_buffer_uptodate(bh))
922 		return bh;
923 
924 	ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
925 	if (ret) {
926 		put_bh(bh);
927 		return ERR_PTR(ret);
928 	}
929 	return bh;
930 }
931 
932 /* Read a contiguous batch of blocks. */
ext4_bread_batch(struct inode * inode,ext4_lblk_t block,int bh_count,bool wait,struct buffer_head ** bhs)933 int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
934 		     bool wait, struct buffer_head **bhs)
935 {
936 	int i, err;
937 
938 	for (i = 0; i < bh_count; i++) {
939 		bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
940 		if (IS_ERR(bhs[i])) {
941 			err = PTR_ERR(bhs[i]);
942 			bh_count = i;
943 			goto out_brelse;
944 		}
945 	}
946 
947 	for (i = 0; i < bh_count; i++)
948 		/* Note that NULL bhs[i] is valid because of holes. */
949 		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
950 			ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
951 
952 	if (!wait)
953 		return 0;
954 
955 	for (i = 0; i < bh_count; i++)
956 		if (bhs[i])
957 			wait_on_buffer(bhs[i]);
958 
959 	for (i = 0; i < bh_count; i++) {
960 		if (bhs[i] && !buffer_uptodate(bhs[i])) {
961 			err = -EIO;
962 			goto out_brelse;
963 		}
964 	}
965 	return 0;
966 
967 out_brelse:
968 	for (i = 0; i < bh_count; i++) {
969 		brelse(bhs[i]);
970 		bhs[i] = NULL;
971 	}
972 	return err;
973 }
974 
ext4_walk_page_buffers(handle_t * handle,struct inode * inode,struct buffer_head * head,unsigned from,unsigned to,int * partial,int (* fn)(handle_t * handle,struct inode * inode,struct buffer_head * bh))975 int ext4_walk_page_buffers(handle_t *handle, struct inode *inode,
976 			   struct buffer_head *head,
977 			   unsigned from,
978 			   unsigned to,
979 			   int *partial,
980 			   int (*fn)(handle_t *handle, struct inode *inode,
981 				     struct buffer_head *bh))
982 {
983 	struct buffer_head *bh;
984 	unsigned block_start, block_end;
985 	unsigned blocksize = head->b_size;
986 	int err, ret = 0;
987 	struct buffer_head *next;
988 
989 	for (bh = head, block_start = 0;
990 	     ret == 0 && (bh != head || !block_start);
991 	     block_start = block_end, bh = next) {
992 		next = bh->b_this_page;
993 		block_end = block_start + blocksize;
994 		if (block_end <= from || block_start >= to) {
995 			if (partial && !buffer_uptodate(bh))
996 				*partial = 1;
997 			continue;
998 		}
999 		err = (*fn)(handle, inode, bh);
1000 		if (!ret)
1001 			ret = err;
1002 	}
1003 	return ret;
1004 }
1005 
1006 /*
1007  * Helper for handling dirtying of journalled data. We also mark the folio as
1008  * dirty so that writeback code knows about this page (and inode) contains
1009  * dirty data. ext4_writepages() then commits appropriate transaction to
1010  * make data stable.
1011  */
ext4_dirty_journalled_data(handle_t * handle,struct buffer_head * bh)1012 static int ext4_dirty_journalled_data(handle_t *handle, struct buffer_head *bh)
1013 {
1014 	folio_mark_dirty(bh->b_folio);
1015 	return ext4_handle_dirty_metadata(handle, NULL, bh);
1016 }
1017 
do_journal_get_write_access(handle_t * handle,struct inode * inode,struct buffer_head * bh)1018 int do_journal_get_write_access(handle_t *handle, struct inode *inode,
1019 				struct buffer_head *bh)
1020 {
1021 	int dirty = buffer_dirty(bh);
1022 	int ret;
1023 
1024 	if (!buffer_mapped(bh) || buffer_freed(bh))
1025 		return 0;
1026 	/*
1027 	 * __block_write_begin() could have dirtied some buffers. Clean
1028 	 * the dirty bit as jbd2_journal_get_write_access() could complain
1029 	 * otherwise about fs integrity issues. Setting of the dirty bit
1030 	 * by __block_write_begin() isn't a real problem here as we clear
1031 	 * the bit before releasing a page lock and thus writeback cannot
1032 	 * ever write the buffer.
1033 	 */
1034 	if (dirty)
1035 		clear_buffer_dirty(bh);
1036 	BUFFER_TRACE(bh, "get write access");
1037 	ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1038 					    EXT4_JTR_NONE);
1039 	if (!ret && dirty)
1040 		ret = ext4_dirty_journalled_data(handle, bh);
1041 	return ret;
1042 }
1043 
1044 #ifdef CONFIG_FS_ENCRYPTION
ext4_block_write_begin(struct folio * folio,loff_t pos,unsigned len,get_block_t * get_block)1045 static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
1046 				  get_block_t *get_block)
1047 {
1048 	unsigned from = pos & (PAGE_SIZE - 1);
1049 	unsigned to = from + len;
1050 	struct inode *inode = folio->mapping->host;
1051 	unsigned block_start, block_end;
1052 	sector_t block;
1053 	int err = 0;
1054 	unsigned blocksize = inode->i_sb->s_blocksize;
1055 	unsigned bbits;
1056 	struct buffer_head *bh, *head, *wait[2];
1057 	int nr_wait = 0;
1058 	int i;
1059 
1060 	BUG_ON(!folio_test_locked(folio));
1061 	BUG_ON(from > PAGE_SIZE);
1062 	BUG_ON(to > PAGE_SIZE);
1063 	BUG_ON(from > to);
1064 
1065 	head = folio_buffers(folio);
1066 	if (!head)
1067 		head = create_empty_buffers(folio, blocksize, 0);
1068 	bbits = ilog2(blocksize);
1069 	block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
1070 
1071 	for (bh = head, block_start = 0; bh != head || !block_start;
1072 	    block++, block_start = block_end, bh = bh->b_this_page) {
1073 		block_end = block_start + blocksize;
1074 		if (block_end <= from || block_start >= to) {
1075 			if (folio_test_uptodate(folio)) {
1076 				set_buffer_uptodate(bh);
1077 			}
1078 			continue;
1079 		}
1080 		if (buffer_new(bh))
1081 			clear_buffer_new(bh);
1082 		if (!buffer_mapped(bh)) {
1083 			WARN_ON(bh->b_size != blocksize);
1084 			err = get_block(inode, block, bh, 1);
1085 			if (err)
1086 				break;
1087 			if (buffer_new(bh)) {
1088 				if (folio_test_uptodate(folio)) {
1089 					clear_buffer_new(bh);
1090 					set_buffer_uptodate(bh);
1091 					mark_buffer_dirty(bh);
1092 					continue;
1093 				}
1094 				if (block_end > to || block_start < from)
1095 					folio_zero_segments(folio, to,
1096 							    block_end,
1097 							    block_start, from);
1098 				continue;
1099 			}
1100 		}
1101 		if (folio_test_uptodate(folio)) {
1102 			set_buffer_uptodate(bh);
1103 			continue;
1104 		}
1105 		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1106 		    !buffer_unwritten(bh) &&
1107 		    (block_start < from || block_end > to)) {
1108 			ext4_read_bh_lock(bh, 0, false);
1109 			wait[nr_wait++] = bh;
1110 		}
1111 	}
1112 	/*
1113 	 * If we issued read requests, let them complete.
1114 	 */
1115 	for (i = 0; i < nr_wait; i++) {
1116 		wait_on_buffer(wait[i]);
1117 		if (!buffer_uptodate(wait[i]))
1118 			err = -EIO;
1119 	}
1120 	if (unlikely(err)) {
1121 		folio_zero_new_buffers(folio, from, to);
1122 	} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1123 		for (i = 0; i < nr_wait; i++) {
1124 			int err2;
1125 
1126 			err2 = fscrypt_decrypt_pagecache_blocks(folio,
1127 						blocksize, bh_offset(wait[i]));
1128 			if (err2) {
1129 				clear_buffer_uptodate(wait[i]);
1130 				err = err2;
1131 			}
1132 		}
1133 	}
1134 
1135 	return err;
1136 }
1137 #endif
1138 
1139 /*
1140  * To preserve ordering, it is essential that the hole instantiation and
1141  * the data write be encapsulated in a single transaction.  We cannot
1142  * close off a transaction and start a new one between the ext4_get_block()
1143  * and the ext4_write_end().  So doing the jbd2_journal_start at the start of
1144  * ext4_write_begin() is the right place.
1145  */
ext4_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)1146 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1147 			    loff_t pos, unsigned len,
1148 			    struct folio **foliop, void **fsdata)
1149 {
1150 	struct inode *inode = mapping->host;
1151 	int ret, needed_blocks;
1152 	handle_t *handle;
1153 	int retries = 0;
1154 	struct folio *folio;
1155 	pgoff_t index;
1156 	unsigned from, to;
1157 
1158 	if (unlikely(ext4_forced_shutdown(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 						    foliop);
1174 		if (ret < 0)
1175 			return ret;
1176 		if (ret == 1)
1177 			return 0;
1178 	}
1179 
1180 	/*
1181 	 * __filemap_get_folio() can take a long time if the
1182 	 * system is thrashing due to memory pressure, or if the folio
1183 	 * is being written back.  So grab it first before we start
1184 	 * the transaction handle.  This also allows us to allocate
1185 	 * the folio (if needed) without using GFP_NOFS.
1186 	 */
1187 retry_grab:
1188 	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
1189 					mapping_gfp_mask(mapping));
1190 	if (IS_ERR(folio))
1191 		return PTR_ERR(folio);
1192 	/*
1193 	 * The same as page allocation, we prealloc buffer heads before
1194 	 * starting the handle.
1195 	 */
1196 	if (!folio_buffers(folio))
1197 		create_empty_buffers(folio, inode->i_sb->s_blocksize, 0);
1198 
1199 	folio_unlock(folio);
1200 
1201 retry_journal:
1202 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1203 	if (IS_ERR(handle)) {
1204 		folio_put(folio);
1205 		return PTR_ERR(handle);
1206 	}
1207 
1208 	folio_lock(folio);
1209 	if (folio->mapping != mapping) {
1210 		/* The folio got truncated from under us */
1211 		folio_unlock(folio);
1212 		folio_put(folio);
1213 		ext4_journal_stop(handle);
1214 		goto retry_grab;
1215 	}
1216 	/* In case writeback began while the folio was unlocked */
1217 	folio_wait_stable(folio);
1218 
1219 #ifdef CONFIG_FS_ENCRYPTION
1220 	if (ext4_should_dioread_nolock(inode))
1221 		ret = ext4_block_write_begin(folio, pos, len,
1222 					     ext4_get_block_unwritten);
1223 	else
1224 		ret = ext4_block_write_begin(folio, pos, len, ext4_get_block);
1225 #else
1226 	if (ext4_should_dioread_nolock(inode))
1227 		ret = __block_write_begin(folio, pos, len,
1228 					  ext4_get_block_unwritten);
1229 	else
1230 		ret = __block_write_begin(folio, pos, len, ext4_get_block);
1231 #endif
1232 	if (!ret && ext4_should_journal_data(inode)) {
1233 		ret = ext4_walk_page_buffers(handle, inode,
1234 					     folio_buffers(folio), from, to,
1235 					     NULL, do_journal_get_write_access);
1236 	}
1237 
1238 	if (ret) {
1239 		bool extended = (pos + len > inode->i_size) &&
1240 				!ext4_verity_in_progress(inode);
1241 
1242 		folio_unlock(folio);
1243 		/*
1244 		 * __block_write_begin may have instantiated a few blocks
1245 		 * outside i_size.  Trim these off again. Don't need
1246 		 * i_size_read because we hold i_rwsem.
1247 		 *
1248 		 * Add inode to orphan list in case we crash before
1249 		 * truncate finishes
1250 		 */
1251 		if (extended && ext4_can_truncate(inode))
1252 			ext4_orphan_add(handle, inode);
1253 
1254 		ext4_journal_stop(handle);
1255 		if (extended) {
1256 			ext4_truncate_failed_write(inode);
1257 			/*
1258 			 * If truncate failed early the inode might
1259 			 * still be on the orphan list; we need to
1260 			 * make sure the inode is removed from the
1261 			 * orphan list in that case.
1262 			 */
1263 			if (inode->i_nlink)
1264 				ext4_orphan_del(NULL, inode);
1265 		}
1266 
1267 		if (ret == -ENOSPC &&
1268 		    ext4_should_retry_alloc(inode->i_sb, &retries))
1269 			goto retry_journal;
1270 		folio_put(folio);
1271 		return ret;
1272 	}
1273 	*foliop = folio;
1274 	return ret;
1275 }
1276 
1277 /* For write_end() in data=journal mode */
write_end_fn(handle_t * handle,struct inode * inode,struct buffer_head * bh)1278 static int write_end_fn(handle_t *handle, struct inode *inode,
1279 			struct buffer_head *bh)
1280 {
1281 	int ret;
1282 	if (!buffer_mapped(bh) || buffer_freed(bh))
1283 		return 0;
1284 	set_buffer_uptodate(bh);
1285 	ret = ext4_dirty_journalled_data(handle, bh);
1286 	clear_buffer_meta(bh);
1287 	clear_buffer_prio(bh);
1288 	return ret;
1289 }
1290 
1291 /*
1292  * We need to pick up the new inode size which generic_commit_write gave us
1293  * `file' can be NULL - eg, when called from page_symlink().
1294  *
1295  * ext4 never places buffers on inode->i_mapping->i_private_list.  metadata
1296  * buffers are managed internally.
1297  */
ext4_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)1298 static int ext4_write_end(struct file *file,
1299 			  struct address_space *mapping,
1300 			  loff_t pos, unsigned len, unsigned copied,
1301 			  struct folio *folio, void *fsdata)
1302 {
1303 	handle_t *handle = ext4_journal_current_handle();
1304 	struct inode *inode = mapping->host;
1305 	loff_t old_size = inode->i_size;
1306 	int ret = 0, ret2;
1307 	int i_size_changed = 0;
1308 	bool verity = ext4_verity_in_progress(inode);
1309 
1310 	trace_ext4_write_end(inode, pos, len, copied);
1311 
1312 	if (ext4_has_inline_data(inode) &&
1313 	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
1314 		return ext4_write_inline_data_end(inode, pos, len, copied,
1315 						  folio);
1316 
1317 	copied = block_write_end(file, mapping, pos, len, copied, folio, fsdata);
1318 	/*
1319 	 * it's important to update i_size while still holding folio lock:
1320 	 * page writeout could otherwise come in and zero beyond i_size.
1321 	 *
1322 	 * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1323 	 * blocks are being written past EOF, so skip the i_size update.
1324 	 */
1325 	if (!verity)
1326 		i_size_changed = ext4_update_inode_size(inode, pos + copied);
1327 	folio_unlock(folio);
1328 	folio_put(folio);
1329 
1330 	if (old_size < pos && !verity)
1331 		pagecache_isize_extended(inode, old_size, pos);
1332 	/*
1333 	 * Don't mark the inode dirty under folio lock. First, it unnecessarily
1334 	 * makes the holding time of folio lock longer. Second, it forces lock
1335 	 * ordering of folio lock and transaction start for journaling
1336 	 * filesystems.
1337 	 */
1338 	if (i_size_changed)
1339 		ret = ext4_mark_inode_dirty(handle, inode);
1340 
1341 	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1342 		/* if we have allocated more blocks and copied
1343 		 * less. We will have blocks allocated outside
1344 		 * inode->i_size. So truncate them
1345 		 */
1346 		ext4_orphan_add(handle, inode);
1347 
1348 	ret2 = ext4_journal_stop(handle);
1349 	if (!ret)
1350 		ret = ret2;
1351 
1352 	if (pos + len > inode->i_size && !verity) {
1353 		ext4_truncate_failed_write(inode);
1354 		/*
1355 		 * If truncate failed early the inode might still be
1356 		 * on the orphan list; we need to make sure the inode
1357 		 * is removed from the orphan list in that case.
1358 		 */
1359 		if (inode->i_nlink)
1360 			ext4_orphan_del(NULL, inode);
1361 	}
1362 
1363 	return ret ? ret : copied;
1364 }
1365 
1366 /*
1367  * This is a private version of folio_zero_new_buffers() which doesn't
1368  * set the buffer to be dirty, since in data=journalled mode we need
1369  * to call ext4_dirty_journalled_data() instead.
1370  */
ext4_journalled_zero_new_buffers(handle_t * handle,struct inode * inode,struct folio * folio,unsigned from,unsigned to)1371 static void ext4_journalled_zero_new_buffers(handle_t *handle,
1372 					    struct inode *inode,
1373 					    struct folio *folio,
1374 					    unsigned from, unsigned to)
1375 {
1376 	unsigned int block_start = 0, block_end;
1377 	struct buffer_head *head, *bh;
1378 
1379 	bh = head = folio_buffers(folio);
1380 	do {
1381 		block_end = block_start + bh->b_size;
1382 		if (buffer_new(bh)) {
1383 			if (block_end > from && block_start < to) {
1384 				if (!folio_test_uptodate(folio)) {
1385 					unsigned start, size;
1386 
1387 					start = max(from, block_start);
1388 					size = min(to, block_end) - start;
1389 
1390 					folio_zero_range(folio, start, size);
1391 					write_end_fn(handle, inode, bh);
1392 				}
1393 				clear_buffer_new(bh);
1394 			}
1395 		}
1396 		block_start = block_end;
1397 		bh = bh->b_this_page;
1398 	} while (bh != head);
1399 }
1400 
ext4_journalled_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)1401 static int ext4_journalled_write_end(struct file *file,
1402 				     struct address_space *mapping,
1403 				     loff_t pos, unsigned len, unsigned copied,
1404 				     struct folio *folio, void *fsdata)
1405 {
1406 	handle_t *handle = ext4_journal_current_handle();
1407 	struct inode *inode = mapping->host;
1408 	loff_t old_size = inode->i_size;
1409 	int ret = 0, ret2;
1410 	int partial = 0;
1411 	unsigned from, to;
1412 	int size_changed = 0;
1413 	bool verity = ext4_verity_in_progress(inode);
1414 
1415 	trace_ext4_journalled_write_end(inode, pos, len, copied);
1416 	from = pos & (PAGE_SIZE - 1);
1417 	to = from + len;
1418 
1419 	BUG_ON(!ext4_handle_valid(handle));
1420 
1421 	if (ext4_has_inline_data(inode))
1422 		return ext4_write_inline_data_end(inode, pos, len, copied,
1423 						  folio);
1424 
1425 	if (unlikely(copied < len) && !folio_test_uptodate(folio)) {
1426 		copied = 0;
1427 		ext4_journalled_zero_new_buffers(handle, inode, folio,
1428 						 from, to);
1429 	} else {
1430 		if (unlikely(copied < len))
1431 			ext4_journalled_zero_new_buffers(handle, inode, folio,
1432 							 from + copied, to);
1433 		ret = ext4_walk_page_buffers(handle, inode,
1434 					     folio_buffers(folio),
1435 					     from, from + copied, &partial,
1436 					     write_end_fn);
1437 		if (!partial)
1438 			folio_mark_uptodate(folio);
1439 	}
1440 	if (!verity)
1441 		size_changed = ext4_update_inode_size(inode, pos + copied);
1442 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1443 	folio_unlock(folio);
1444 	folio_put(folio);
1445 
1446 	if (old_size < pos && !verity)
1447 		pagecache_isize_extended(inode, old_size, pos);
1448 
1449 	if (size_changed) {
1450 		ret2 = ext4_mark_inode_dirty(handle, inode);
1451 		if (!ret)
1452 			ret = ret2;
1453 	}
1454 
1455 	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1456 		/* if we have allocated more blocks and copied
1457 		 * less. We will have blocks allocated outside
1458 		 * inode->i_size. So truncate them
1459 		 */
1460 		ext4_orphan_add(handle, inode);
1461 
1462 	ret2 = ext4_journal_stop(handle);
1463 	if (!ret)
1464 		ret = ret2;
1465 	if (pos + len > inode->i_size && !verity) {
1466 		ext4_truncate_failed_write(inode);
1467 		/*
1468 		 * If truncate failed early the inode might still be
1469 		 * on the orphan list; we need to make sure the inode
1470 		 * is removed from the orphan list in that case.
1471 		 */
1472 		if (inode->i_nlink)
1473 			ext4_orphan_del(NULL, inode);
1474 	}
1475 
1476 	return ret ? ret : copied;
1477 }
1478 
1479 /*
1480  * Reserve space for 'nr_resv' clusters
1481  */
ext4_da_reserve_space(struct inode * inode,int nr_resv)1482 static int ext4_da_reserve_space(struct inode *inode, int nr_resv)
1483 {
1484 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1485 	struct ext4_inode_info *ei = EXT4_I(inode);
1486 	int ret;
1487 
1488 	/*
1489 	 * We will charge metadata quota at writeout time; this saves
1490 	 * us from metadata over-estimation, though we may go over by
1491 	 * a small amount in the end.  Here we just reserve for data.
1492 	 */
1493 	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, nr_resv));
1494 	if (ret)
1495 		return ret;
1496 
1497 	spin_lock(&ei->i_block_reservation_lock);
1498 	if (ext4_claim_free_clusters(sbi, nr_resv, 0)) {
1499 		spin_unlock(&ei->i_block_reservation_lock);
1500 		dquot_release_reservation_block(inode, EXT4_C2B(sbi, nr_resv));
1501 		return -ENOSPC;
1502 	}
1503 	ei->i_reserved_data_blocks += nr_resv;
1504 	trace_ext4_da_reserve_space(inode, nr_resv);
1505 	spin_unlock(&ei->i_block_reservation_lock);
1506 
1507 	return 0;       /* success */
1508 }
1509 
ext4_da_release_space(struct inode * inode,int to_free)1510 void ext4_da_release_space(struct inode *inode, int to_free)
1511 {
1512 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1513 	struct ext4_inode_info *ei = EXT4_I(inode);
1514 
1515 	if (!to_free)
1516 		return;		/* Nothing to release, exit */
1517 
1518 	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1519 
1520 	trace_ext4_da_release_space(inode, to_free);
1521 	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1522 		/*
1523 		 * if there aren't enough reserved blocks, then the
1524 		 * counter is messed up somewhere.  Since this
1525 		 * function is called from invalidate page, it's
1526 		 * harmless to return without any action.
1527 		 */
1528 		ext4_warning(inode->i_sb, "ext4_da_release_space: "
1529 			 "ino %lu, to_free %d with only %d reserved "
1530 			 "data blocks", inode->i_ino, to_free,
1531 			 ei->i_reserved_data_blocks);
1532 		WARN_ON(1);
1533 		to_free = ei->i_reserved_data_blocks;
1534 	}
1535 	ei->i_reserved_data_blocks -= to_free;
1536 
1537 	/* update fs dirty data blocks counter */
1538 	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1539 
1540 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1541 
1542 	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1543 }
1544 
1545 /*
1546  * Delayed allocation stuff
1547  */
1548 
1549 struct mpage_da_data {
1550 	/* These are input fields for ext4_do_writepages() */
1551 	struct inode *inode;
1552 	struct writeback_control *wbc;
1553 	unsigned int can_map:1;	/* Can writepages call map blocks? */
1554 
1555 	/* These are internal state of ext4_do_writepages() */
1556 	pgoff_t first_page;	/* The first page to write */
1557 	pgoff_t next_page;	/* Current page to examine */
1558 	pgoff_t last_page;	/* Last page to examine */
1559 	/*
1560 	 * Extent to map - this can be after first_page because that can be
1561 	 * fully mapped. We somewhat abuse m_flags to store whether the extent
1562 	 * is delalloc or unwritten.
1563 	 */
1564 	struct ext4_map_blocks map;
1565 	struct ext4_io_submit io_submit;	/* IO submission data */
1566 	unsigned int do_map:1;
1567 	unsigned int scanned_until_end:1;
1568 	unsigned int journalled_more_data:1;
1569 };
1570 
mpage_release_unused_pages(struct mpage_da_data * mpd,bool invalidate)1571 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1572 				       bool invalidate)
1573 {
1574 	unsigned nr, i;
1575 	pgoff_t index, end;
1576 	struct folio_batch fbatch;
1577 	struct inode *inode = mpd->inode;
1578 	struct address_space *mapping = inode->i_mapping;
1579 
1580 	/* This is necessary when next_page == 0. */
1581 	if (mpd->first_page >= mpd->next_page)
1582 		return;
1583 
1584 	mpd->scanned_until_end = 0;
1585 	index = mpd->first_page;
1586 	end   = mpd->next_page - 1;
1587 	if (invalidate) {
1588 		ext4_lblk_t start, last;
1589 		start = index << (PAGE_SHIFT - inode->i_blkbits);
1590 		last = end << (PAGE_SHIFT - inode->i_blkbits);
1591 
1592 		/*
1593 		 * avoid racing with extent status tree scans made by
1594 		 * ext4_insert_delayed_block()
1595 		 */
1596 		down_write(&EXT4_I(inode)->i_data_sem);
1597 		ext4_es_remove_extent(inode, start, last - start + 1);
1598 		up_write(&EXT4_I(inode)->i_data_sem);
1599 	}
1600 
1601 	folio_batch_init(&fbatch);
1602 	while (index <= end) {
1603 		nr = filemap_get_folios(mapping, &index, end, &fbatch);
1604 		if (nr == 0)
1605 			break;
1606 		for (i = 0; i < nr; i++) {
1607 			struct folio *folio = fbatch.folios[i];
1608 
1609 			if (folio->index < mpd->first_page)
1610 				continue;
1611 			if (folio_next_index(folio) - 1 > end)
1612 				continue;
1613 			BUG_ON(!folio_test_locked(folio));
1614 			BUG_ON(folio_test_writeback(folio));
1615 			if (invalidate) {
1616 				if (folio_mapped(folio))
1617 					folio_clear_dirty_for_io(folio);
1618 				block_invalidate_folio(folio, 0,
1619 						folio_size(folio));
1620 				folio_clear_uptodate(folio);
1621 			}
1622 			folio_unlock(folio);
1623 		}
1624 		folio_batch_release(&fbatch);
1625 	}
1626 }
1627 
ext4_print_free_blocks(struct inode * inode)1628 static void ext4_print_free_blocks(struct inode *inode)
1629 {
1630 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1631 	struct super_block *sb = inode->i_sb;
1632 	struct ext4_inode_info *ei = EXT4_I(inode);
1633 
1634 	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1635 	       EXT4_C2B(EXT4_SB(inode->i_sb),
1636 			ext4_count_free_clusters(sb)));
1637 	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1638 	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1639 	       (long long) EXT4_C2B(EXT4_SB(sb),
1640 		percpu_counter_sum(&sbi->s_freeclusters_counter)));
1641 	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1642 	       (long long) EXT4_C2B(EXT4_SB(sb),
1643 		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1644 	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1645 	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1646 		 ei->i_reserved_data_blocks);
1647 	return;
1648 }
1649 
1650 /*
1651  * Check whether the cluster containing lblk has been allocated or has
1652  * delalloc reservation.
1653  *
1654  * Returns 0 if the cluster doesn't have either, 1 if it has delalloc
1655  * reservation, 2 if it's already been allocated, negative error code on
1656  * failure.
1657  */
ext4_clu_alloc_state(struct inode * inode,ext4_lblk_t lblk)1658 static int ext4_clu_alloc_state(struct inode *inode, ext4_lblk_t lblk)
1659 {
1660 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1661 	int ret;
1662 
1663 	/* Has delalloc reservation? */
1664 	if (ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk))
1665 		return 1;
1666 
1667 	/* Already been allocated? */
1668 	if (ext4_es_scan_clu(inode, &ext4_es_is_mapped, lblk))
1669 		return 2;
1670 	ret = ext4_clu_mapped(inode, EXT4_B2C(sbi, lblk));
1671 	if (ret < 0)
1672 		return ret;
1673 	if (ret > 0)
1674 		return 2;
1675 
1676 	return 0;
1677 }
1678 
1679 /*
1680  * ext4_insert_delayed_blocks - adds a multiple delayed blocks to the extents
1681  *                              status tree, incrementing the reserved
1682  *                              cluster/block count or making pending
1683  *                              reservations where needed
1684  *
1685  * @inode - file containing the newly added block
1686  * @lblk - start logical block to be added
1687  * @len - length of blocks to be added
1688  *
1689  * Returns 0 on success, negative error code on failure.
1690  */
ext4_insert_delayed_blocks(struct inode * inode,ext4_lblk_t lblk,ext4_lblk_t len)1691 static int ext4_insert_delayed_blocks(struct inode *inode, ext4_lblk_t lblk,
1692 				      ext4_lblk_t len)
1693 {
1694 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1695 	int ret;
1696 	bool lclu_allocated = false;
1697 	bool end_allocated = false;
1698 	ext4_lblk_t resv_clu;
1699 	ext4_lblk_t end = lblk + len - 1;
1700 
1701 	/*
1702 	 * If the cluster containing lblk or end is shared with a delayed,
1703 	 * written, or unwritten extent in a bigalloc file system, it's
1704 	 * already been accounted for and does not need to be reserved.
1705 	 * A pending reservation must be made for the cluster if it's
1706 	 * shared with a written or unwritten extent and doesn't already
1707 	 * have one.  Written and unwritten extents can be purged from the
1708 	 * extents status tree if the system is under memory pressure, so
1709 	 * it's necessary to examine the extent tree if a search of the
1710 	 * extents status tree doesn't get a match.
1711 	 */
1712 	if (sbi->s_cluster_ratio == 1) {
1713 		ret = ext4_da_reserve_space(inode, len);
1714 		if (ret != 0)   /* ENOSPC */
1715 			return ret;
1716 	} else {   /* bigalloc */
1717 		resv_clu = EXT4_B2C(sbi, end) - EXT4_B2C(sbi, lblk) + 1;
1718 
1719 		ret = ext4_clu_alloc_state(inode, lblk);
1720 		if (ret < 0)
1721 			return ret;
1722 		if (ret > 0) {
1723 			resv_clu--;
1724 			lclu_allocated = (ret == 2);
1725 		}
1726 
1727 		if (EXT4_B2C(sbi, lblk) != EXT4_B2C(sbi, end)) {
1728 			ret = ext4_clu_alloc_state(inode, end);
1729 			if (ret < 0)
1730 				return ret;
1731 			if (ret > 0) {
1732 				resv_clu--;
1733 				end_allocated = (ret == 2);
1734 			}
1735 		}
1736 
1737 		if (resv_clu) {
1738 			ret = ext4_da_reserve_space(inode, resv_clu);
1739 			if (ret != 0)   /* ENOSPC */
1740 				return ret;
1741 		}
1742 	}
1743 
1744 	ext4_es_insert_delayed_extent(inode, lblk, len, lclu_allocated,
1745 				      end_allocated);
1746 	return 0;
1747 }
1748 
1749 /*
1750  * Looks up the requested blocks and sets the delalloc extent map.
1751  * First try to look up for the extent entry that contains the requested
1752  * blocks in the extent status tree without i_data_sem, then try to look
1753  * up for the ondisk extent mapping with i_data_sem in read mode,
1754  * finally hold i_data_sem in write mode, looks up again and add a
1755  * delalloc extent entry if it still couldn't find any extent. Pass out
1756  * the mapped extent through @map and return 0 on success.
1757  */
ext4_da_map_blocks(struct inode * inode,struct ext4_map_blocks * map)1758 static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map)
1759 {
1760 	struct extent_status es;
1761 	int retval;
1762 #ifdef ES_AGGRESSIVE_TEST
1763 	struct ext4_map_blocks orig_map;
1764 
1765 	memcpy(&orig_map, map, sizeof(*map));
1766 #endif
1767 
1768 	map->m_flags = 0;
1769 	ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1770 		  (unsigned long) map->m_lblk);
1771 
1772 	/* Lookup extent status tree firstly */
1773 	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
1774 		map->m_len = min_t(unsigned int, map->m_len,
1775 				   es.es_len - (map->m_lblk - es.es_lblk));
1776 
1777 		if (ext4_es_is_hole(&es))
1778 			goto add_delayed;
1779 
1780 found:
1781 		/*
1782 		 * Delayed extent could be allocated by fallocate.
1783 		 * So we need to check it.
1784 		 */
1785 		if (ext4_es_is_delonly(&es)) {
1786 			map->m_flags |= EXT4_MAP_DELAYED;
1787 			return 0;
1788 		}
1789 
1790 		map->m_pblk = ext4_es_pblock(&es) + map->m_lblk - es.es_lblk;
1791 		if (ext4_es_is_written(&es))
1792 			map->m_flags |= EXT4_MAP_MAPPED;
1793 		else if (ext4_es_is_unwritten(&es))
1794 			map->m_flags |= EXT4_MAP_UNWRITTEN;
1795 		else
1796 			BUG();
1797 
1798 #ifdef ES_AGGRESSIVE_TEST
1799 		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1800 #endif
1801 		return 0;
1802 	}
1803 
1804 	/*
1805 	 * Try to see if we can get the block without requesting a new
1806 	 * file system block.
1807 	 */
1808 	down_read(&EXT4_I(inode)->i_data_sem);
1809 	if (ext4_has_inline_data(inode))
1810 		retval = 0;
1811 	else
1812 		retval = ext4_map_query_blocks(NULL, inode, map);
1813 	up_read(&EXT4_I(inode)->i_data_sem);
1814 	if (retval)
1815 		return retval < 0 ? retval : 0;
1816 
1817 add_delayed:
1818 	down_write(&EXT4_I(inode)->i_data_sem);
1819 	/*
1820 	 * Page fault path (ext4_page_mkwrite does not take i_rwsem)
1821 	 * and fallocate path (no folio lock) can race. Make sure we
1822 	 * lookup the extent status tree here again while i_data_sem
1823 	 * is held in write mode, before inserting a new da entry in
1824 	 * the extent status tree.
1825 	 */
1826 	if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
1827 		map->m_len = min_t(unsigned int, map->m_len,
1828 				   es.es_len - (map->m_lblk - es.es_lblk));
1829 
1830 		if (!ext4_es_is_hole(&es)) {
1831 			up_write(&EXT4_I(inode)->i_data_sem);
1832 			goto found;
1833 		}
1834 	} else if (!ext4_has_inline_data(inode)) {
1835 		retval = ext4_map_query_blocks(NULL, inode, map);
1836 		if (retval) {
1837 			up_write(&EXT4_I(inode)->i_data_sem);
1838 			return retval < 0 ? retval : 0;
1839 		}
1840 	}
1841 
1842 	map->m_flags |= EXT4_MAP_DELAYED;
1843 	retval = ext4_insert_delayed_blocks(inode, map->m_lblk, map->m_len);
1844 	up_write(&EXT4_I(inode)->i_data_sem);
1845 
1846 	return retval;
1847 }
1848 
1849 /*
1850  * This is a special get_block_t callback which is used by
1851  * ext4_da_write_begin().  It will either return mapped block or
1852  * reserve space for a single block.
1853  *
1854  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1855  * We also have b_blocknr = -1 and b_bdev initialized properly
1856  *
1857  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1858  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1859  * initialized properly.
1860  */
ext4_da_get_block_prep(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)1861 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1862 			   struct buffer_head *bh, int create)
1863 {
1864 	struct ext4_map_blocks map;
1865 	sector_t invalid_block = ~((sector_t) 0xffff);
1866 	int ret = 0;
1867 
1868 	BUG_ON(create == 0);
1869 	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1870 
1871 	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1872 		invalid_block = ~0;
1873 
1874 	map.m_lblk = iblock;
1875 	map.m_len = 1;
1876 
1877 	/*
1878 	 * first, we need to know whether the block is allocated already
1879 	 * preallocated blocks are unmapped but should treated
1880 	 * the same as allocated blocks.
1881 	 */
1882 	ret = ext4_da_map_blocks(inode, &map);
1883 	if (ret < 0)
1884 		return ret;
1885 
1886 	if (map.m_flags & EXT4_MAP_DELAYED) {
1887 		map_bh(bh, inode->i_sb, invalid_block);
1888 		set_buffer_new(bh);
1889 		set_buffer_delay(bh);
1890 		return 0;
1891 	}
1892 
1893 	map_bh(bh, inode->i_sb, map.m_pblk);
1894 	ext4_update_bh_state(bh, map.m_flags);
1895 
1896 	if (buffer_unwritten(bh)) {
1897 		/* A delayed write to unwritten bh should be marked
1898 		 * new and mapped.  Mapped ensures that we don't do
1899 		 * get_block multiple times when we write to the same
1900 		 * offset and new ensures that we do proper zero out
1901 		 * for partial write.
1902 		 */
1903 		set_buffer_new(bh);
1904 		set_buffer_mapped(bh);
1905 	}
1906 	return 0;
1907 }
1908 
mpage_folio_done(struct mpage_da_data * mpd,struct folio * folio)1909 static void mpage_folio_done(struct mpage_da_data *mpd, struct folio *folio)
1910 {
1911 	mpd->first_page += folio_nr_pages(folio);
1912 	folio_unlock(folio);
1913 }
1914 
mpage_submit_folio(struct mpage_da_data * mpd,struct folio * folio)1915 static int mpage_submit_folio(struct mpage_da_data *mpd, struct folio *folio)
1916 {
1917 	size_t len;
1918 	loff_t size;
1919 	int err;
1920 
1921 	BUG_ON(folio->index != mpd->first_page);
1922 	folio_clear_dirty_for_io(folio);
1923 	/*
1924 	 * We have to be very careful here!  Nothing protects writeback path
1925 	 * against i_size changes and the page can be writeably mapped into
1926 	 * page tables. So an application can be growing i_size and writing
1927 	 * data through mmap while writeback runs. folio_clear_dirty_for_io()
1928 	 * write-protects our page in page tables and the page cannot get
1929 	 * written to again until we release folio lock. So only after
1930 	 * folio_clear_dirty_for_io() we are safe to sample i_size for
1931 	 * ext4_bio_write_folio() to zero-out tail of the written page. We rely
1932 	 * on the barrier provided by folio_test_clear_dirty() in
1933 	 * folio_clear_dirty_for_io() to make sure i_size is really sampled only
1934 	 * after page tables are updated.
1935 	 */
1936 	size = i_size_read(mpd->inode);
1937 	len = folio_size(folio);
1938 	if (folio_pos(folio) + len > size &&
1939 	    !ext4_verity_in_progress(mpd->inode))
1940 		len = size & (len - 1);
1941 	err = ext4_bio_write_folio(&mpd->io_submit, folio, len);
1942 	if (!err)
1943 		mpd->wbc->nr_to_write--;
1944 
1945 	return err;
1946 }
1947 
1948 #define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
1949 
1950 /*
1951  * mballoc gives us at most this number of blocks...
1952  * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
1953  * The rest of mballoc seems to handle chunks up to full group size.
1954  */
1955 #define MAX_WRITEPAGES_EXTENT_LEN 2048
1956 
1957 /*
1958  * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
1959  *
1960  * @mpd - extent of blocks
1961  * @lblk - logical number of the block in the file
1962  * @bh - buffer head we want to add to the extent
1963  *
1964  * The function is used to collect contig. blocks in the same state. If the
1965  * buffer doesn't require mapping for writeback and we haven't started the
1966  * extent of buffers to map yet, the function returns 'true' immediately - the
1967  * caller can write the buffer right away. Otherwise the function returns true
1968  * if the block has been added to the extent, false if the block couldn't be
1969  * added.
1970  */
mpage_add_bh_to_extent(struct mpage_da_data * mpd,ext4_lblk_t lblk,struct buffer_head * bh)1971 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
1972 				   struct buffer_head *bh)
1973 {
1974 	struct ext4_map_blocks *map = &mpd->map;
1975 
1976 	/* Buffer that doesn't need mapping for writeback? */
1977 	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
1978 	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
1979 		/* So far no extent to map => we write the buffer right away */
1980 		if (map->m_len == 0)
1981 			return true;
1982 		return false;
1983 	}
1984 
1985 	/* First block in the extent? */
1986 	if (map->m_len == 0) {
1987 		/* We cannot map unless handle is started... */
1988 		if (!mpd->do_map)
1989 			return false;
1990 		map->m_lblk = lblk;
1991 		map->m_len = 1;
1992 		map->m_flags = bh->b_state & BH_FLAGS;
1993 		return true;
1994 	}
1995 
1996 	/* Don't go larger than mballoc is willing to allocate */
1997 	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
1998 		return false;
1999 
2000 	/* Can we merge the block to our big extent? */
2001 	if (lblk == map->m_lblk + map->m_len &&
2002 	    (bh->b_state & BH_FLAGS) == map->m_flags) {
2003 		map->m_len++;
2004 		return true;
2005 	}
2006 	return false;
2007 }
2008 
2009 /*
2010  * mpage_process_page_bufs - submit page buffers for IO or add them to extent
2011  *
2012  * @mpd - extent of blocks for mapping
2013  * @head - the first buffer in the page
2014  * @bh - buffer we should start processing from
2015  * @lblk - logical number of the block in the file corresponding to @bh
2016  *
2017  * Walk through page buffers from @bh upto @head (exclusive) and either submit
2018  * the page for IO if all buffers in this page were mapped and there's no
2019  * accumulated extent of buffers to map or add buffers in the page to the
2020  * extent of buffers to map. The function returns 1 if the caller can continue
2021  * by processing the next page, 0 if it should stop adding buffers to the
2022  * extent to map because we cannot extend it anymore. It can also return value
2023  * < 0 in case of error during IO submission.
2024  */
mpage_process_page_bufs(struct mpage_da_data * mpd,struct buffer_head * head,struct buffer_head * bh,ext4_lblk_t lblk)2025 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
2026 				   struct buffer_head *head,
2027 				   struct buffer_head *bh,
2028 				   ext4_lblk_t lblk)
2029 {
2030 	struct inode *inode = mpd->inode;
2031 	int err;
2032 	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
2033 							>> inode->i_blkbits;
2034 
2035 	if (ext4_verity_in_progress(inode))
2036 		blocks = EXT_MAX_BLOCKS;
2037 
2038 	do {
2039 		BUG_ON(buffer_locked(bh));
2040 
2041 		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
2042 			/* Found extent to map? */
2043 			if (mpd->map.m_len)
2044 				return 0;
2045 			/* Buffer needs mapping and handle is not started? */
2046 			if (!mpd->do_map)
2047 				return 0;
2048 			/* Everything mapped so far and we hit EOF */
2049 			break;
2050 		}
2051 	} while (lblk++, (bh = bh->b_this_page) != head);
2052 	/* So far everything mapped? Submit the page for IO. */
2053 	if (mpd->map.m_len == 0) {
2054 		err = mpage_submit_folio(mpd, head->b_folio);
2055 		if (err < 0)
2056 			return err;
2057 		mpage_folio_done(mpd, head->b_folio);
2058 	}
2059 	if (lblk >= blocks) {
2060 		mpd->scanned_until_end = 1;
2061 		return 0;
2062 	}
2063 	return 1;
2064 }
2065 
2066 /*
2067  * mpage_process_folio - update folio buffers corresponding to changed extent
2068  *			 and may submit fully mapped page for IO
2069  * @mpd: description of extent to map, on return next extent to map
2070  * @folio: Contains these buffers.
2071  * @m_lblk: logical block mapping.
2072  * @m_pblk: corresponding physical mapping.
2073  * @map_bh: determines on return whether this page requires any further
2074  *		  mapping or not.
2075  *
2076  * Scan given folio buffers corresponding to changed extent and update buffer
2077  * state according to new extent state.
2078  * We map delalloc buffers to their physical location, clear unwritten bits.
2079  * If the given folio is not fully mapped, we update @mpd to the next extent in
2080  * the given folio that needs mapping & return @map_bh as true.
2081  */
mpage_process_folio(struct mpage_da_data * mpd,struct folio * folio,ext4_lblk_t * m_lblk,ext4_fsblk_t * m_pblk,bool * map_bh)2082 static int mpage_process_folio(struct mpage_da_data *mpd, struct folio *folio,
2083 			      ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2084 			      bool *map_bh)
2085 {
2086 	struct buffer_head *head, *bh;
2087 	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2088 	ext4_lblk_t lblk = *m_lblk;
2089 	ext4_fsblk_t pblock = *m_pblk;
2090 	int err = 0;
2091 	int blkbits = mpd->inode->i_blkbits;
2092 	ssize_t io_end_size = 0;
2093 	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2094 
2095 	bh = head = folio_buffers(folio);
2096 	do {
2097 		if (lblk < mpd->map.m_lblk)
2098 			continue;
2099 		if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2100 			/*
2101 			 * Buffer after end of mapped extent.
2102 			 * Find next buffer in the folio to map.
2103 			 */
2104 			mpd->map.m_len = 0;
2105 			mpd->map.m_flags = 0;
2106 			io_end_vec->size += io_end_size;
2107 
2108 			err = mpage_process_page_bufs(mpd, head, bh, lblk);
2109 			if (err > 0)
2110 				err = 0;
2111 			if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2112 				io_end_vec = ext4_alloc_io_end_vec(io_end);
2113 				if (IS_ERR(io_end_vec)) {
2114 					err = PTR_ERR(io_end_vec);
2115 					goto out;
2116 				}
2117 				io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2118 			}
2119 			*map_bh = true;
2120 			goto out;
2121 		}
2122 		if (buffer_delay(bh)) {
2123 			clear_buffer_delay(bh);
2124 			bh->b_blocknr = pblock++;
2125 		}
2126 		clear_buffer_unwritten(bh);
2127 		io_end_size += (1 << blkbits);
2128 	} while (lblk++, (bh = bh->b_this_page) != head);
2129 
2130 	io_end_vec->size += io_end_size;
2131 	*map_bh = false;
2132 out:
2133 	*m_lblk = lblk;
2134 	*m_pblk = pblock;
2135 	return err;
2136 }
2137 
2138 /*
2139  * mpage_map_buffers - update buffers corresponding to changed extent and
2140  *		       submit fully mapped pages for IO
2141  *
2142  * @mpd - description of extent to map, on return next extent to map
2143  *
2144  * Scan buffers corresponding to changed extent (we expect corresponding pages
2145  * to be already locked) and update buffer state according to new extent state.
2146  * We map delalloc buffers to their physical location, clear unwritten bits,
2147  * and mark buffers as uninit when we perform writes to unwritten extents
2148  * and do extent conversion after IO is finished. If the last page is not fully
2149  * mapped, we update @map to the next extent in the last page that needs
2150  * mapping. Otherwise we submit the page for IO.
2151  */
mpage_map_and_submit_buffers(struct mpage_da_data * mpd)2152 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2153 {
2154 	struct folio_batch fbatch;
2155 	unsigned nr, i;
2156 	struct inode *inode = mpd->inode;
2157 	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2158 	pgoff_t start, end;
2159 	ext4_lblk_t lblk;
2160 	ext4_fsblk_t pblock;
2161 	int err;
2162 	bool map_bh = false;
2163 
2164 	start = mpd->map.m_lblk >> bpp_bits;
2165 	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2166 	lblk = start << bpp_bits;
2167 	pblock = mpd->map.m_pblk;
2168 
2169 	folio_batch_init(&fbatch);
2170 	while (start <= end) {
2171 		nr = filemap_get_folios(inode->i_mapping, &start, end, &fbatch);
2172 		if (nr == 0)
2173 			break;
2174 		for (i = 0; i < nr; i++) {
2175 			struct folio *folio = fbatch.folios[i];
2176 
2177 			err = mpage_process_folio(mpd, folio, &lblk, &pblock,
2178 						 &map_bh);
2179 			/*
2180 			 * If map_bh is true, means page may require further bh
2181 			 * mapping, or maybe the page was submitted for IO.
2182 			 * So we return to call further extent mapping.
2183 			 */
2184 			if (err < 0 || map_bh)
2185 				goto out;
2186 			/* Page fully mapped - let IO run! */
2187 			err = mpage_submit_folio(mpd, folio);
2188 			if (err < 0)
2189 				goto out;
2190 			mpage_folio_done(mpd, folio);
2191 		}
2192 		folio_batch_release(&fbatch);
2193 	}
2194 	/* Extent fully mapped and matches with page boundary. We are done. */
2195 	mpd->map.m_len = 0;
2196 	mpd->map.m_flags = 0;
2197 	return 0;
2198 out:
2199 	folio_batch_release(&fbatch);
2200 	return err;
2201 }
2202 
mpage_map_one_extent(handle_t * handle,struct mpage_da_data * mpd)2203 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2204 {
2205 	struct inode *inode = mpd->inode;
2206 	struct ext4_map_blocks *map = &mpd->map;
2207 	int get_blocks_flags;
2208 	int err, dioread_nolock;
2209 
2210 	trace_ext4_da_write_pages_extent(inode, map);
2211 	/*
2212 	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2213 	 * to convert an unwritten extent to be initialized (in the case
2214 	 * where we have written into one or more preallocated blocks).  It is
2215 	 * possible that we're going to need more metadata blocks than
2216 	 * previously reserved. However we must not fail because we're in
2217 	 * writeback and there is nothing we can do about it so it might result
2218 	 * in data loss.  So use reserved blocks to allocate metadata if
2219 	 * possible.
2220 	 *
2221 	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2222 	 * the blocks in question are delalloc blocks.  This indicates
2223 	 * that the blocks and quotas has already been checked when
2224 	 * the data was copied into the page cache.
2225 	 */
2226 	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2227 			   EXT4_GET_BLOCKS_METADATA_NOFAIL |
2228 			   EXT4_GET_BLOCKS_IO_SUBMIT;
2229 	dioread_nolock = ext4_should_dioread_nolock(inode);
2230 	if (dioread_nolock)
2231 		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2232 	if (map->m_flags & BIT(BH_Delay))
2233 		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2234 
2235 	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2236 	if (err < 0)
2237 		return err;
2238 	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2239 		if (!mpd->io_submit.io_end->handle &&
2240 		    ext4_handle_valid(handle)) {
2241 			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2242 			handle->h_rsv_handle = NULL;
2243 		}
2244 		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2245 	}
2246 
2247 	BUG_ON(map->m_len == 0);
2248 	return 0;
2249 }
2250 
2251 /*
2252  * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2253  *				 mpd->len and submit pages underlying it for IO
2254  *
2255  * @handle - handle for journal operations
2256  * @mpd - extent to map
2257  * @give_up_on_write - we set this to true iff there is a fatal error and there
2258  *                     is no hope of writing the data. The caller should discard
2259  *                     dirty pages to avoid infinite loops.
2260  *
2261  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2262  * delayed, blocks are allocated, if it is unwritten, we may need to convert
2263  * them to initialized or split the described range from larger unwritten
2264  * extent. Note that we need not map all the described range since allocation
2265  * can return less blocks or the range is covered by more unwritten extents. We
2266  * cannot map more because we are limited by reserved transaction credits. On
2267  * the other hand we always make sure that the last touched page is fully
2268  * mapped so that it can be written out (and thus forward progress is
2269  * guaranteed). After mapping we submit all mapped pages for IO.
2270  */
mpage_map_and_submit_extent(handle_t * handle,struct mpage_da_data * mpd,bool * give_up_on_write)2271 static int mpage_map_and_submit_extent(handle_t *handle,
2272 				       struct mpage_da_data *mpd,
2273 				       bool *give_up_on_write)
2274 {
2275 	struct inode *inode = mpd->inode;
2276 	struct ext4_map_blocks *map = &mpd->map;
2277 	int err;
2278 	loff_t disksize;
2279 	int progress = 0;
2280 	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2281 	struct ext4_io_end_vec *io_end_vec;
2282 
2283 	io_end_vec = ext4_alloc_io_end_vec(io_end);
2284 	if (IS_ERR(io_end_vec))
2285 		return PTR_ERR(io_end_vec);
2286 	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2287 	do {
2288 		err = mpage_map_one_extent(handle, mpd);
2289 		if (err < 0) {
2290 			struct super_block *sb = inode->i_sb;
2291 
2292 			if (ext4_forced_shutdown(sb))
2293 				goto invalidate_dirty_pages;
2294 			/*
2295 			 * Let the uper layers retry transient errors.
2296 			 * In the case of ENOSPC, if ext4_count_free_blocks()
2297 			 * is non-zero, a commit should free up blocks.
2298 			 */
2299 			if ((err == -ENOMEM) ||
2300 			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2301 				if (progress)
2302 					goto update_disksize;
2303 				return err;
2304 			}
2305 			ext4_msg(sb, KERN_CRIT,
2306 				 "Delayed block allocation failed for "
2307 				 "inode %lu at logical offset %llu with"
2308 				 " max blocks %u with error %d",
2309 				 inode->i_ino,
2310 				 (unsigned long long)map->m_lblk,
2311 				 (unsigned)map->m_len, -err);
2312 			ext4_msg(sb, KERN_CRIT,
2313 				 "This should not happen!! Data will "
2314 				 "be lost\n");
2315 			if (err == -ENOSPC)
2316 				ext4_print_free_blocks(inode);
2317 		invalidate_dirty_pages:
2318 			*give_up_on_write = true;
2319 			return err;
2320 		}
2321 		progress = 1;
2322 		/*
2323 		 * Update buffer state, submit mapped pages, and get us new
2324 		 * extent to map
2325 		 */
2326 		err = mpage_map_and_submit_buffers(mpd);
2327 		if (err < 0)
2328 			goto update_disksize;
2329 	} while (map->m_len);
2330 
2331 update_disksize:
2332 	/*
2333 	 * Update on-disk size after IO is submitted.  Races with
2334 	 * truncate are avoided by checking i_size under i_data_sem.
2335 	 */
2336 	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2337 	if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2338 		int err2;
2339 		loff_t i_size;
2340 
2341 		down_write(&EXT4_I(inode)->i_data_sem);
2342 		i_size = i_size_read(inode);
2343 		if (disksize > i_size)
2344 			disksize = i_size;
2345 		if (disksize > EXT4_I(inode)->i_disksize)
2346 			EXT4_I(inode)->i_disksize = disksize;
2347 		up_write(&EXT4_I(inode)->i_data_sem);
2348 		err2 = ext4_mark_inode_dirty(handle, inode);
2349 		if (err2) {
2350 			ext4_error_err(inode->i_sb, -err2,
2351 				       "Failed to mark inode %lu dirty",
2352 				       inode->i_ino);
2353 		}
2354 		if (!err)
2355 			err = err2;
2356 	}
2357 	return err;
2358 }
2359 
2360 /*
2361  * Calculate the total number of credits to reserve for one writepages
2362  * iteration. This is called from ext4_writepages(). We map an extent of
2363  * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2364  * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2365  * bpp - 1 blocks in bpp different extents.
2366  */
ext4_da_writepages_trans_blocks(struct inode * inode)2367 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2368 {
2369 	int bpp = ext4_journal_blocks_per_page(inode);
2370 
2371 	return ext4_meta_trans_blocks(inode,
2372 				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2373 }
2374 
ext4_journal_folio_buffers(handle_t * handle,struct folio * folio,size_t len)2375 static int ext4_journal_folio_buffers(handle_t *handle, struct folio *folio,
2376 				     size_t len)
2377 {
2378 	struct buffer_head *page_bufs = folio_buffers(folio);
2379 	struct inode *inode = folio->mapping->host;
2380 	int ret, err;
2381 
2382 	ret = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
2383 				     NULL, do_journal_get_write_access);
2384 	err = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
2385 				     NULL, write_end_fn);
2386 	if (ret == 0)
2387 		ret = err;
2388 	err = ext4_jbd2_inode_add_write(handle, inode, folio_pos(folio), len);
2389 	if (ret == 0)
2390 		ret = err;
2391 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
2392 
2393 	return ret;
2394 }
2395 
mpage_journal_page_buffers(handle_t * handle,struct mpage_da_data * mpd,struct folio * folio)2396 static int mpage_journal_page_buffers(handle_t *handle,
2397 				      struct mpage_da_data *mpd,
2398 				      struct folio *folio)
2399 {
2400 	struct inode *inode = mpd->inode;
2401 	loff_t size = i_size_read(inode);
2402 	size_t len = folio_size(folio);
2403 
2404 	folio_clear_checked(folio);
2405 	mpd->wbc->nr_to_write--;
2406 
2407 	if (folio_pos(folio) + len > size &&
2408 	    !ext4_verity_in_progress(inode))
2409 		len = size & (len - 1);
2410 
2411 	return ext4_journal_folio_buffers(handle, folio, len);
2412 }
2413 
2414 /*
2415  * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2416  * 				 needing mapping, submit mapped pages
2417  *
2418  * @mpd - where to look for pages
2419  *
2420  * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2421  * IO immediately. If we cannot map blocks, we submit just already mapped
2422  * buffers in the page for IO and keep page dirty. When we can map blocks and
2423  * we find a page which isn't mapped we start accumulating extent of buffers
2424  * underlying these pages that needs mapping (formed by either delayed or
2425  * unwritten buffers). We also lock the pages containing these buffers. The
2426  * extent found is returned in @mpd structure (starting at mpd->lblk with
2427  * length mpd->len blocks).
2428  *
2429  * Note that this function can attach bios to one io_end structure which are
2430  * neither logically nor physically contiguous. Although it may seem as an
2431  * unnecessary complication, it is actually inevitable in blocksize < pagesize
2432  * case as we need to track IO to all buffers underlying a page in one io_end.
2433  */
mpage_prepare_extent_to_map(struct mpage_da_data * mpd)2434 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2435 {
2436 	struct address_space *mapping = mpd->inode->i_mapping;
2437 	struct folio_batch fbatch;
2438 	unsigned int nr_folios;
2439 	pgoff_t index = mpd->first_page;
2440 	pgoff_t end = mpd->last_page;
2441 	xa_mark_t tag;
2442 	int i, err = 0;
2443 	int blkbits = mpd->inode->i_blkbits;
2444 	ext4_lblk_t lblk;
2445 	struct buffer_head *head;
2446 	handle_t *handle = NULL;
2447 	int bpp = ext4_journal_blocks_per_page(mpd->inode);
2448 
2449 	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2450 		tag = PAGECACHE_TAG_TOWRITE;
2451 	else
2452 		tag = PAGECACHE_TAG_DIRTY;
2453 
2454 	mpd->map.m_len = 0;
2455 	mpd->next_page = index;
2456 	if (ext4_should_journal_data(mpd->inode)) {
2457 		handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,
2458 					    bpp);
2459 		if (IS_ERR(handle))
2460 			return PTR_ERR(handle);
2461 	}
2462 	folio_batch_init(&fbatch);
2463 	while (index <= end) {
2464 		nr_folios = filemap_get_folios_tag(mapping, &index, end,
2465 				tag, &fbatch);
2466 		if (nr_folios == 0)
2467 			break;
2468 
2469 		for (i = 0; i < nr_folios; i++) {
2470 			struct folio *folio = fbatch.folios[i];
2471 
2472 			/*
2473 			 * Accumulated enough dirty pages? This doesn't apply
2474 			 * to WB_SYNC_ALL mode. For integrity sync we have to
2475 			 * keep going because someone may be concurrently
2476 			 * dirtying pages, and we might have synced a lot of
2477 			 * newly appeared dirty pages, but have not synced all
2478 			 * of the old dirty pages.
2479 			 */
2480 			if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
2481 			    mpd->wbc->nr_to_write <=
2482 			    mpd->map.m_len >> (PAGE_SHIFT - blkbits))
2483 				goto out;
2484 
2485 			/* If we can't merge this page, we are done. */
2486 			if (mpd->map.m_len > 0 && mpd->next_page != folio->index)
2487 				goto out;
2488 
2489 			if (handle) {
2490 				err = ext4_journal_ensure_credits(handle, bpp,
2491 								  0);
2492 				if (err < 0)
2493 					goto out;
2494 			}
2495 
2496 			folio_lock(folio);
2497 			/*
2498 			 * If the page is no longer dirty, or its mapping no
2499 			 * longer corresponds to inode we are writing (which
2500 			 * means it has been truncated or invalidated), or the
2501 			 * page is already under writeback and we are not doing
2502 			 * a data integrity writeback, skip the page
2503 			 */
2504 			if (!folio_test_dirty(folio) ||
2505 			    (folio_test_writeback(folio) &&
2506 			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2507 			    unlikely(folio->mapping != mapping)) {
2508 				folio_unlock(folio);
2509 				continue;
2510 			}
2511 
2512 			folio_wait_writeback(folio);
2513 			BUG_ON(folio_test_writeback(folio));
2514 
2515 			/*
2516 			 * Should never happen but for buggy code in
2517 			 * other subsystems that call
2518 			 * set_page_dirty() without properly warning
2519 			 * the file system first.  See [1] for more
2520 			 * information.
2521 			 *
2522 			 * [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
2523 			 */
2524 			if (!folio_buffers(folio)) {
2525 				ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", folio->index);
2526 				folio_clear_dirty(folio);
2527 				folio_unlock(folio);
2528 				continue;
2529 			}
2530 
2531 			if (mpd->map.m_len == 0)
2532 				mpd->first_page = folio->index;
2533 			mpd->next_page = folio_next_index(folio);
2534 			/*
2535 			 * Writeout when we cannot modify metadata is simple.
2536 			 * Just submit the page. For data=journal mode we
2537 			 * first handle writeout of the page for checkpoint and
2538 			 * only after that handle delayed page dirtying. This
2539 			 * makes sure current data is checkpointed to the final
2540 			 * location before possibly journalling it again which
2541 			 * is desirable when the page is frequently dirtied
2542 			 * through a pin.
2543 			 */
2544 			if (!mpd->can_map) {
2545 				err = mpage_submit_folio(mpd, folio);
2546 				if (err < 0)
2547 					goto out;
2548 				/* Pending dirtying of journalled data? */
2549 				if (folio_test_checked(folio)) {
2550 					err = mpage_journal_page_buffers(handle,
2551 						mpd, folio);
2552 					if (err < 0)
2553 						goto out;
2554 					mpd->journalled_more_data = 1;
2555 				}
2556 				mpage_folio_done(mpd, folio);
2557 			} else {
2558 				/* Add all dirty buffers to mpd */
2559 				lblk = ((ext4_lblk_t)folio->index) <<
2560 					(PAGE_SHIFT - blkbits);
2561 				head = folio_buffers(folio);
2562 				err = mpage_process_page_bufs(mpd, head, head,
2563 						lblk);
2564 				if (err <= 0)
2565 					goto out;
2566 				err = 0;
2567 			}
2568 		}
2569 		folio_batch_release(&fbatch);
2570 		cond_resched();
2571 	}
2572 	mpd->scanned_until_end = 1;
2573 	if (handle)
2574 		ext4_journal_stop(handle);
2575 	return 0;
2576 out:
2577 	folio_batch_release(&fbatch);
2578 	if (handle)
2579 		ext4_journal_stop(handle);
2580 	return err;
2581 }
2582 
ext4_do_writepages(struct mpage_da_data * mpd)2583 static int ext4_do_writepages(struct mpage_da_data *mpd)
2584 {
2585 	struct writeback_control *wbc = mpd->wbc;
2586 	pgoff_t	writeback_index = 0;
2587 	long nr_to_write = wbc->nr_to_write;
2588 	int range_whole = 0;
2589 	int cycled = 1;
2590 	handle_t *handle = NULL;
2591 	struct inode *inode = mpd->inode;
2592 	struct address_space *mapping = inode->i_mapping;
2593 	int needed_blocks, rsv_blocks = 0, ret = 0;
2594 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2595 	struct blk_plug plug;
2596 	bool give_up_on_write = false;
2597 
2598 	trace_ext4_writepages(inode, wbc);
2599 
2600 	/*
2601 	 * No pages to write? This is mainly a kludge to avoid starting
2602 	 * a transaction for special inodes like journal inode on last iput()
2603 	 * because that could violate lock ordering on umount
2604 	 */
2605 	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2606 		goto out_writepages;
2607 
2608 	/*
2609 	 * If the filesystem has aborted, it is read-only, so return
2610 	 * right away instead of dumping stack traces later on that
2611 	 * will obscure the real source of the problem.  We test
2612 	 * fs shutdown state instead of sb->s_flag's SB_RDONLY because
2613 	 * the latter could be true if the filesystem is mounted
2614 	 * read-only, and in that case, ext4_writepages should
2615 	 * *never* be called, so if that ever happens, we would want
2616 	 * the stack trace.
2617 	 */
2618 	if (unlikely(ext4_forced_shutdown(mapping->host->i_sb))) {
2619 		ret = -EROFS;
2620 		goto out_writepages;
2621 	}
2622 
2623 	/*
2624 	 * If we have inline data and arrive here, it means that
2625 	 * we will soon create the block for the 1st page, so
2626 	 * we'd better clear the inline data here.
2627 	 */
2628 	if (ext4_has_inline_data(inode)) {
2629 		/* Just inode will be modified... */
2630 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2631 		if (IS_ERR(handle)) {
2632 			ret = PTR_ERR(handle);
2633 			goto out_writepages;
2634 		}
2635 		BUG_ON(ext4_test_inode_state(inode,
2636 				EXT4_STATE_MAY_INLINE_DATA));
2637 		ext4_destroy_inline_data(handle, inode);
2638 		ext4_journal_stop(handle);
2639 	}
2640 
2641 	/*
2642 	 * data=journal mode does not do delalloc so we just need to writeout /
2643 	 * journal already mapped buffers. On the other hand we need to commit
2644 	 * transaction to make data stable. We expect all the data to be
2645 	 * already in the journal (the only exception are DMA pinned pages
2646 	 * dirtied behind our back) so we commit transaction here and run the
2647 	 * writeback loop to checkpoint them. The checkpointing is not actually
2648 	 * necessary to make data persistent *but* quite a few places (extent
2649 	 * shifting operations, fsverity, ...) depend on being able to drop
2650 	 * pagecache pages after calling filemap_write_and_wait() and for that
2651 	 * checkpointing needs to happen.
2652 	 */
2653 	if (ext4_should_journal_data(inode)) {
2654 		mpd->can_map = 0;
2655 		if (wbc->sync_mode == WB_SYNC_ALL)
2656 			ext4_fc_commit(sbi->s_journal,
2657 				       EXT4_I(inode)->i_datasync_tid);
2658 	}
2659 	mpd->journalled_more_data = 0;
2660 
2661 	if (ext4_should_dioread_nolock(inode)) {
2662 		/*
2663 		 * We may need to convert up to one extent per block in
2664 		 * the page and we may dirty the inode.
2665 		 */
2666 		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2667 						PAGE_SIZE >> inode->i_blkbits);
2668 	}
2669 
2670 	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2671 		range_whole = 1;
2672 
2673 	if (wbc->range_cyclic) {
2674 		writeback_index = mapping->writeback_index;
2675 		if (writeback_index)
2676 			cycled = 0;
2677 		mpd->first_page = writeback_index;
2678 		mpd->last_page = -1;
2679 	} else {
2680 		mpd->first_page = wbc->range_start >> PAGE_SHIFT;
2681 		mpd->last_page = wbc->range_end >> PAGE_SHIFT;
2682 	}
2683 
2684 	ext4_io_submit_init(&mpd->io_submit, wbc);
2685 retry:
2686 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2687 		tag_pages_for_writeback(mapping, mpd->first_page,
2688 					mpd->last_page);
2689 	blk_start_plug(&plug);
2690 
2691 	/*
2692 	 * First writeback pages that don't need mapping - we can avoid
2693 	 * starting a transaction unnecessarily and also avoid being blocked
2694 	 * in the block layer on device congestion while having transaction
2695 	 * started.
2696 	 */
2697 	mpd->do_map = 0;
2698 	mpd->scanned_until_end = 0;
2699 	mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2700 	if (!mpd->io_submit.io_end) {
2701 		ret = -ENOMEM;
2702 		goto unplug;
2703 	}
2704 	ret = mpage_prepare_extent_to_map(mpd);
2705 	/* Unlock pages we didn't use */
2706 	mpage_release_unused_pages(mpd, false);
2707 	/* Submit prepared bio */
2708 	ext4_io_submit(&mpd->io_submit);
2709 	ext4_put_io_end_defer(mpd->io_submit.io_end);
2710 	mpd->io_submit.io_end = NULL;
2711 	if (ret < 0)
2712 		goto unplug;
2713 
2714 	while (!mpd->scanned_until_end && wbc->nr_to_write > 0) {
2715 		/* For each extent of pages we use new io_end */
2716 		mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2717 		if (!mpd->io_submit.io_end) {
2718 			ret = -ENOMEM;
2719 			break;
2720 		}
2721 
2722 		WARN_ON_ONCE(!mpd->can_map);
2723 		/*
2724 		 * We have two constraints: We find one extent to map and we
2725 		 * must always write out whole page (makes a difference when
2726 		 * blocksize < pagesize) so that we don't block on IO when we
2727 		 * try to write out the rest of the page. Journalled mode is
2728 		 * not supported by delalloc.
2729 		 */
2730 		BUG_ON(ext4_should_journal_data(inode));
2731 		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2732 
2733 		/* start a new transaction */
2734 		handle = ext4_journal_start_with_reserve(inode,
2735 				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2736 		if (IS_ERR(handle)) {
2737 			ret = PTR_ERR(handle);
2738 			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2739 			       "%ld pages, ino %lu; err %d", __func__,
2740 				wbc->nr_to_write, inode->i_ino, ret);
2741 			/* Release allocated io_end */
2742 			ext4_put_io_end(mpd->io_submit.io_end);
2743 			mpd->io_submit.io_end = NULL;
2744 			break;
2745 		}
2746 		mpd->do_map = 1;
2747 
2748 		trace_ext4_da_write_pages(inode, mpd->first_page, wbc);
2749 		ret = mpage_prepare_extent_to_map(mpd);
2750 		if (!ret && mpd->map.m_len)
2751 			ret = mpage_map_and_submit_extent(handle, mpd,
2752 					&give_up_on_write);
2753 		/*
2754 		 * Caution: If the handle is synchronous,
2755 		 * ext4_journal_stop() can wait for transaction commit
2756 		 * to finish which may depend on writeback of pages to
2757 		 * complete or on page lock to be released.  In that
2758 		 * case, we have to wait until after we have
2759 		 * submitted all the IO, released page locks we hold,
2760 		 * and dropped io_end reference (for extent conversion
2761 		 * to be able to complete) before stopping the handle.
2762 		 */
2763 		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2764 			ext4_journal_stop(handle);
2765 			handle = NULL;
2766 			mpd->do_map = 0;
2767 		}
2768 		/* Unlock pages we didn't use */
2769 		mpage_release_unused_pages(mpd, give_up_on_write);
2770 		/* Submit prepared bio */
2771 		ext4_io_submit(&mpd->io_submit);
2772 
2773 		/*
2774 		 * Drop our io_end reference we got from init. We have
2775 		 * to be careful and use deferred io_end finishing if
2776 		 * we are still holding the transaction as we can
2777 		 * release the last reference to io_end which may end
2778 		 * up doing unwritten extent conversion.
2779 		 */
2780 		if (handle) {
2781 			ext4_put_io_end_defer(mpd->io_submit.io_end);
2782 			ext4_journal_stop(handle);
2783 		} else
2784 			ext4_put_io_end(mpd->io_submit.io_end);
2785 		mpd->io_submit.io_end = NULL;
2786 
2787 		if (ret == -ENOSPC && sbi->s_journal) {
2788 			/*
2789 			 * Commit the transaction which would
2790 			 * free blocks released in the transaction
2791 			 * and try again
2792 			 */
2793 			jbd2_journal_force_commit_nested(sbi->s_journal);
2794 			ret = 0;
2795 			continue;
2796 		}
2797 		/* Fatal error - ENOMEM, EIO... */
2798 		if (ret)
2799 			break;
2800 	}
2801 unplug:
2802 	blk_finish_plug(&plug);
2803 	if (!ret && !cycled && wbc->nr_to_write > 0) {
2804 		cycled = 1;
2805 		mpd->last_page = writeback_index - 1;
2806 		mpd->first_page = 0;
2807 		goto retry;
2808 	}
2809 
2810 	/* Update index */
2811 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2812 		/*
2813 		 * Set the writeback_index so that range_cyclic
2814 		 * mode will write it back later
2815 		 */
2816 		mapping->writeback_index = mpd->first_page;
2817 
2818 out_writepages:
2819 	trace_ext4_writepages_result(inode, wbc, ret,
2820 				     nr_to_write - wbc->nr_to_write);
2821 	return ret;
2822 }
2823 
ext4_writepages(struct address_space * mapping,struct writeback_control * wbc)2824 static int ext4_writepages(struct address_space *mapping,
2825 			   struct writeback_control *wbc)
2826 {
2827 	struct super_block *sb = mapping->host->i_sb;
2828 	struct mpage_da_data mpd = {
2829 		.inode = mapping->host,
2830 		.wbc = wbc,
2831 		.can_map = 1,
2832 	};
2833 	int ret;
2834 	int alloc_ctx;
2835 
2836 	if (unlikely(ext4_forced_shutdown(sb)))
2837 		return -EIO;
2838 
2839 	alloc_ctx = ext4_writepages_down_read(sb);
2840 	ret = ext4_do_writepages(&mpd);
2841 	/*
2842 	 * For data=journal writeback we could have come across pages marked
2843 	 * for delayed dirtying (PageChecked) which were just added to the
2844 	 * running transaction. Try once more to get them to stable storage.
2845 	 */
2846 	if (!ret && mpd.journalled_more_data)
2847 		ret = ext4_do_writepages(&mpd);
2848 	ext4_writepages_up_read(sb, alloc_ctx);
2849 
2850 	return ret;
2851 }
2852 
ext4_normal_submit_inode_data_buffers(struct jbd2_inode * jinode)2853 int ext4_normal_submit_inode_data_buffers(struct jbd2_inode *jinode)
2854 {
2855 	struct writeback_control wbc = {
2856 		.sync_mode = WB_SYNC_ALL,
2857 		.nr_to_write = LONG_MAX,
2858 		.range_start = jinode->i_dirty_start,
2859 		.range_end = jinode->i_dirty_end,
2860 	};
2861 	struct mpage_da_data mpd = {
2862 		.inode = jinode->i_vfs_inode,
2863 		.wbc = &wbc,
2864 		.can_map = 0,
2865 	};
2866 	return ext4_do_writepages(&mpd);
2867 }
2868 
ext4_dax_writepages(struct address_space * mapping,struct writeback_control * wbc)2869 static int ext4_dax_writepages(struct address_space *mapping,
2870 			       struct writeback_control *wbc)
2871 {
2872 	int ret;
2873 	long nr_to_write = wbc->nr_to_write;
2874 	struct inode *inode = mapping->host;
2875 	int alloc_ctx;
2876 
2877 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
2878 		return -EIO;
2879 
2880 	alloc_ctx = ext4_writepages_down_read(inode->i_sb);
2881 	trace_ext4_writepages(inode, wbc);
2882 
2883 	ret = dax_writeback_mapping_range(mapping,
2884 					  EXT4_SB(inode->i_sb)->s_daxdev, wbc);
2885 	trace_ext4_writepages_result(inode, wbc, ret,
2886 				     nr_to_write - wbc->nr_to_write);
2887 	ext4_writepages_up_read(inode->i_sb, alloc_ctx);
2888 	return ret;
2889 }
2890 
ext4_nonda_switch(struct super_block * sb)2891 static int ext4_nonda_switch(struct super_block *sb)
2892 {
2893 	s64 free_clusters, dirty_clusters;
2894 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2895 
2896 	/*
2897 	 * switch to non delalloc mode if we are running low
2898 	 * on free block. The free block accounting via percpu
2899 	 * counters can get slightly wrong with percpu_counter_batch getting
2900 	 * accumulated on each CPU without updating global counters
2901 	 * Delalloc need an accurate free block accounting. So switch
2902 	 * to non delalloc when we are near to error range.
2903 	 */
2904 	free_clusters =
2905 		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2906 	dirty_clusters =
2907 		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2908 	/*
2909 	 * Start pushing delalloc when 1/2 of free blocks are dirty.
2910 	 */
2911 	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2912 		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2913 
2914 	if (2 * free_clusters < 3 * dirty_clusters ||
2915 	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2916 		/*
2917 		 * free block count is less than 150% of dirty blocks
2918 		 * or free blocks is less than watermark
2919 		 */
2920 		return 1;
2921 	}
2922 	return 0;
2923 }
2924 
ext4_da_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)2925 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2926 			       loff_t pos, unsigned len,
2927 			       struct folio **foliop, void **fsdata)
2928 {
2929 	int ret, retries = 0;
2930 	struct folio *folio;
2931 	pgoff_t index;
2932 	struct inode *inode = mapping->host;
2933 
2934 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
2935 		return -EIO;
2936 
2937 	index = pos >> PAGE_SHIFT;
2938 
2939 	if (ext4_nonda_switch(inode->i_sb) || ext4_verity_in_progress(inode)) {
2940 		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2941 		return ext4_write_begin(file, mapping, pos,
2942 					len, foliop, fsdata);
2943 	}
2944 	*fsdata = (void *)0;
2945 	trace_ext4_da_write_begin(inode, pos, len);
2946 
2947 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2948 		ret = ext4_da_write_inline_data_begin(mapping, inode, pos, len,
2949 						      foliop, fsdata);
2950 		if (ret < 0)
2951 			return ret;
2952 		if (ret == 1)
2953 			return 0;
2954 	}
2955 
2956 retry:
2957 	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
2958 			mapping_gfp_mask(mapping));
2959 	if (IS_ERR(folio))
2960 		return PTR_ERR(folio);
2961 
2962 #ifdef CONFIG_FS_ENCRYPTION
2963 	ret = ext4_block_write_begin(folio, pos, len, ext4_da_get_block_prep);
2964 #else
2965 	ret = __block_write_begin(folio, pos, len, ext4_da_get_block_prep);
2966 #endif
2967 	if (ret < 0) {
2968 		folio_unlock(folio);
2969 		folio_put(folio);
2970 		/*
2971 		 * block_write_begin may have instantiated a few blocks
2972 		 * outside i_size.  Trim these off again. Don't need
2973 		 * i_size_read because we hold inode lock.
2974 		 */
2975 		if (pos + len > inode->i_size)
2976 			ext4_truncate_failed_write(inode);
2977 
2978 		if (ret == -ENOSPC &&
2979 		    ext4_should_retry_alloc(inode->i_sb, &retries))
2980 			goto retry;
2981 		return ret;
2982 	}
2983 
2984 	*foliop = folio;
2985 	return ret;
2986 }
2987 
2988 /*
2989  * Check if we should update i_disksize
2990  * when write to the end of file but not require block allocation
2991  */
ext4_da_should_update_i_disksize(struct folio * folio,unsigned long offset)2992 static int ext4_da_should_update_i_disksize(struct folio *folio,
2993 					    unsigned long offset)
2994 {
2995 	struct buffer_head *bh;
2996 	struct inode *inode = folio->mapping->host;
2997 	unsigned int idx;
2998 	int i;
2999 
3000 	bh = folio_buffers(folio);
3001 	idx = offset >> inode->i_blkbits;
3002 
3003 	for (i = 0; i < idx; i++)
3004 		bh = bh->b_this_page;
3005 
3006 	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3007 		return 0;
3008 	return 1;
3009 }
3010 
ext4_da_do_write_end(struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio)3011 static int ext4_da_do_write_end(struct address_space *mapping,
3012 			loff_t pos, unsigned len, unsigned copied,
3013 			struct folio *folio)
3014 {
3015 	struct inode *inode = mapping->host;
3016 	loff_t old_size = inode->i_size;
3017 	bool disksize_changed = false;
3018 	loff_t new_i_size;
3019 
3020 	if (unlikely(!folio_buffers(folio))) {
3021 		folio_unlock(folio);
3022 		folio_put(folio);
3023 		return -EIO;
3024 	}
3025 	/*
3026 	 * block_write_end() will mark the inode as dirty with I_DIRTY_PAGES
3027 	 * flag, which all that's needed to trigger page writeback.
3028 	 */
3029 	copied = block_write_end(NULL, mapping, pos, len, copied,
3030 			folio, NULL);
3031 	new_i_size = pos + copied;
3032 
3033 	/*
3034 	 * It's important to update i_size while still holding folio lock,
3035 	 * because folio writeout could otherwise come in and zero beyond
3036 	 * i_size.
3037 	 *
3038 	 * Since we are holding inode lock, we are sure i_disksize <=
3039 	 * i_size. We also know that if i_disksize < i_size, there are
3040 	 * delalloc writes pending in the range up to i_size. If the end of
3041 	 * the current write is <= i_size, there's no need to touch
3042 	 * i_disksize since writeback will push i_disksize up to i_size
3043 	 * eventually. If the end of the current write is > i_size and
3044 	 * inside an allocated block which ext4_da_should_update_i_disksize()
3045 	 * checked, we need to update i_disksize here as certain
3046 	 * ext4_writepages() paths not allocating blocks and update i_disksize.
3047 	 */
3048 	if (new_i_size > inode->i_size) {
3049 		unsigned long end;
3050 
3051 		i_size_write(inode, new_i_size);
3052 		end = (new_i_size - 1) & (PAGE_SIZE - 1);
3053 		if (copied && ext4_da_should_update_i_disksize(folio, end)) {
3054 			ext4_update_i_disksize(inode, new_i_size);
3055 			disksize_changed = true;
3056 		}
3057 	}
3058 
3059 	folio_unlock(folio);
3060 	folio_put(folio);
3061 
3062 	if (old_size < pos)
3063 		pagecache_isize_extended(inode, old_size, pos);
3064 
3065 	if (disksize_changed) {
3066 		handle_t *handle;
3067 
3068 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
3069 		if (IS_ERR(handle))
3070 			return PTR_ERR(handle);
3071 		ext4_mark_inode_dirty(handle, inode);
3072 		ext4_journal_stop(handle);
3073 	}
3074 
3075 	return copied;
3076 }
3077 
ext4_da_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)3078 static int ext4_da_write_end(struct file *file,
3079 			     struct address_space *mapping,
3080 			     loff_t pos, unsigned len, unsigned copied,
3081 			     struct folio *folio, void *fsdata)
3082 {
3083 	struct inode *inode = mapping->host;
3084 	int write_mode = (int)(unsigned long)fsdata;
3085 
3086 	if (write_mode == FALL_BACK_TO_NONDELALLOC)
3087 		return ext4_write_end(file, mapping, pos,
3088 				      len, copied, folio, fsdata);
3089 
3090 	trace_ext4_da_write_end(inode, pos, len, copied);
3091 
3092 	if (write_mode != CONVERT_INLINE_DATA &&
3093 	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3094 	    ext4_has_inline_data(inode))
3095 		return ext4_write_inline_data_end(inode, pos, len, copied,
3096 						  folio);
3097 
3098 	if (unlikely(copied < len) && !folio_test_uptodate(folio))
3099 		copied = 0;
3100 
3101 	return ext4_da_do_write_end(mapping, pos, len, copied, folio);
3102 }
3103 
3104 /*
3105  * Force all delayed allocation blocks to be allocated for a given inode.
3106  */
ext4_alloc_da_blocks(struct inode * inode)3107 int ext4_alloc_da_blocks(struct inode *inode)
3108 {
3109 	trace_ext4_alloc_da_blocks(inode);
3110 
3111 	if (!EXT4_I(inode)->i_reserved_data_blocks)
3112 		return 0;
3113 
3114 	/*
3115 	 * We do something simple for now.  The filemap_flush() will
3116 	 * also start triggering a write of the data blocks, which is
3117 	 * not strictly speaking necessary (and for users of
3118 	 * laptop_mode, not even desirable).  However, to do otherwise
3119 	 * would require replicating code paths in:
3120 	 *
3121 	 * ext4_writepages() ->
3122 	 *    write_cache_pages() ---> (via passed in callback function)
3123 	 *        __mpage_da_writepage() -->
3124 	 *           mpage_add_bh_to_extent()
3125 	 *           mpage_da_map_blocks()
3126 	 *
3127 	 * The problem is that write_cache_pages(), located in
3128 	 * mm/page-writeback.c, marks pages clean in preparation for
3129 	 * doing I/O, which is not desirable if we're not planning on
3130 	 * doing I/O at all.
3131 	 *
3132 	 * We could call write_cache_pages(), and then redirty all of
3133 	 * the pages by calling redirty_page_for_writepage() but that
3134 	 * would be ugly in the extreme.  So instead we would need to
3135 	 * replicate parts of the code in the above functions,
3136 	 * simplifying them because we wouldn't actually intend to
3137 	 * write out the pages, but rather only collect contiguous
3138 	 * logical block extents, call the multi-block allocator, and
3139 	 * then update the buffer heads with the block allocations.
3140 	 *
3141 	 * For now, though, we'll cheat by calling filemap_flush(),
3142 	 * which will map the blocks, and start the I/O, but not
3143 	 * actually wait for the I/O to complete.
3144 	 */
3145 	return filemap_flush(inode->i_mapping);
3146 }
3147 
3148 /*
3149  * bmap() is special.  It gets used by applications such as lilo and by
3150  * the swapper to find the on-disk block of a specific piece of data.
3151  *
3152  * Naturally, this is dangerous if the block concerned is still in the
3153  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3154  * filesystem and enables swap, then they may get a nasty shock when the
3155  * data getting swapped to that swapfile suddenly gets overwritten by
3156  * the original zero's written out previously to the journal and
3157  * awaiting writeback in the kernel's buffer cache.
3158  *
3159  * So, if we see any bmap calls here on a modified, data-journaled file,
3160  * take extra steps to flush any blocks which might be in the cache.
3161  */
ext4_bmap(struct address_space * mapping,sector_t block)3162 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3163 {
3164 	struct inode *inode = mapping->host;
3165 	sector_t ret = 0;
3166 
3167 	inode_lock_shared(inode);
3168 	/*
3169 	 * We can get here for an inline file via the FIBMAP ioctl
3170 	 */
3171 	if (ext4_has_inline_data(inode))
3172 		goto out;
3173 
3174 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3175 	    (test_opt(inode->i_sb, DELALLOC) ||
3176 	     ext4_should_journal_data(inode))) {
3177 		/*
3178 		 * With delalloc or journalled data we want to sync the file so
3179 		 * that we can make sure we allocate blocks for file and data
3180 		 * is in place for the user to see it
3181 		 */
3182 		filemap_write_and_wait(mapping);
3183 	}
3184 
3185 	ret = iomap_bmap(mapping, block, &ext4_iomap_ops);
3186 
3187 out:
3188 	inode_unlock_shared(inode);
3189 	return ret;
3190 }
3191 
ext4_read_folio(struct file * file,struct folio * folio)3192 static int ext4_read_folio(struct file *file, struct folio *folio)
3193 {
3194 	int ret = -EAGAIN;
3195 	struct inode *inode = folio->mapping->host;
3196 
3197 	trace_ext4_read_folio(inode, folio);
3198 
3199 	if (ext4_has_inline_data(inode))
3200 		ret = ext4_readpage_inline(inode, folio);
3201 
3202 	if (ret == -EAGAIN)
3203 		return ext4_mpage_readpages(inode, NULL, folio);
3204 
3205 	return ret;
3206 }
3207 
ext4_readahead(struct readahead_control * rac)3208 static void ext4_readahead(struct readahead_control *rac)
3209 {
3210 	struct inode *inode = rac->mapping->host;
3211 
3212 	/* If the file has inline data, no need to do readahead. */
3213 	if (ext4_has_inline_data(inode))
3214 		return;
3215 
3216 	ext4_mpage_readpages(inode, rac, NULL);
3217 }
3218 
ext4_invalidate_folio(struct folio * folio,size_t offset,size_t length)3219 static void ext4_invalidate_folio(struct folio *folio, size_t offset,
3220 				size_t length)
3221 {
3222 	trace_ext4_invalidate_folio(folio, offset, length);
3223 
3224 	/* No journalling happens on data buffers when this function is used */
3225 	WARN_ON(folio_buffers(folio) && buffer_jbd(folio_buffers(folio)));
3226 
3227 	block_invalidate_folio(folio, offset, length);
3228 }
3229 
__ext4_journalled_invalidate_folio(struct folio * folio,size_t offset,size_t length)3230 static int __ext4_journalled_invalidate_folio(struct folio *folio,
3231 					    size_t offset, size_t length)
3232 {
3233 	journal_t *journal = EXT4_JOURNAL(folio->mapping->host);
3234 
3235 	trace_ext4_journalled_invalidate_folio(folio, offset, length);
3236 
3237 	/*
3238 	 * If it's a full truncate we just forget about the pending dirtying
3239 	 */
3240 	if (offset == 0 && length == folio_size(folio))
3241 		folio_clear_checked(folio);
3242 
3243 	return jbd2_journal_invalidate_folio(journal, folio, offset, length);
3244 }
3245 
3246 /* Wrapper for aops... */
ext4_journalled_invalidate_folio(struct folio * folio,size_t offset,size_t length)3247 static void ext4_journalled_invalidate_folio(struct folio *folio,
3248 					   size_t offset,
3249 					   size_t length)
3250 {
3251 	WARN_ON(__ext4_journalled_invalidate_folio(folio, offset, length) < 0);
3252 }
3253 
ext4_release_folio(struct folio * folio,gfp_t wait)3254 static bool ext4_release_folio(struct folio *folio, gfp_t wait)
3255 {
3256 	struct inode *inode = folio->mapping->host;
3257 	journal_t *journal = EXT4_JOURNAL(inode);
3258 
3259 	trace_ext4_release_folio(inode, folio);
3260 
3261 	/* Page has dirty journalled data -> cannot release */
3262 	if (folio_test_checked(folio))
3263 		return false;
3264 	if (journal)
3265 		return jbd2_journal_try_to_free_buffers(journal, folio);
3266 	else
3267 		return try_to_free_buffers(folio);
3268 }
3269 
ext4_inode_datasync_dirty(struct inode * inode)3270 static bool ext4_inode_datasync_dirty(struct inode *inode)
3271 {
3272 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3273 
3274 	if (journal) {
3275 		if (jbd2_transaction_committed(journal,
3276 			EXT4_I(inode)->i_datasync_tid))
3277 			return false;
3278 		if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3279 			return !list_empty(&EXT4_I(inode)->i_fc_list);
3280 		return true;
3281 	}
3282 
3283 	/* Any metadata buffers to write? */
3284 	if (!list_empty(&inode->i_mapping->i_private_list))
3285 		return true;
3286 	return inode->i_state & I_DIRTY_DATASYNC;
3287 }
3288 
ext4_set_iomap(struct inode * inode,struct iomap * iomap,struct ext4_map_blocks * map,loff_t offset,loff_t length,unsigned int flags)3289 static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3290 			   struct ext4_map_blocks *map, loff_t offset,
3291 			   loff_t length, unsigned int flags)
3292 {
3293 	u8 blkbits = inode->i_blkbits;
3294 
3295 	/*
3296 	 * Writes that span EOF might trigger an I/O size update on completion,
3297 	 * so consider them to be dirty for the purpose of O_DSYNC, even if
3298 	 * there is no other metadata changes being made or are pending.
3299 	 */
3300 	iomap->flags = 0;
3301 	if (ext4_inode_datasync_dirty(inode) ||
3302 	    offset + length > i_size_read(inode))
3303 		iomap->flags |= IOMAP_F_DIRTY;
3304 
3305 	if (map->m_flags & EXT4_MAP_NEW)
3306 		iomap->flags |= IOMAP_F_NEW;
3307 
3308 	if (flags & IOMAP_DAX)
3309 		iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
3310 	else
3311 		iomap->bdev = inode->i_sb->s_bdev;
3312 	iomap->offset = (u64) map->m_lblk << blkbits;
3313 	iomap->length = (u64) map->m_len << blkbits;
3314 
3315 	if ((map->m_flags & EXT4_MAP_MAPPED) &&
3316 	    !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3317 		iomap->flags |= IOMAP_F_MERGED;
3318 
3319 	/*
3320 	 * Flags passed to ext4_map_blocks() for direct I/O writes can result
3321 	 * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3322 	 * set. In order for any allocated unwritten extents to be converted
3323 	 * into written extents correctly within the ->end_io() handler, we
3324 	 * need to ensure that the iomap->type is set appropriately. Hence, the
3325 	 * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3326 	 * been set first.
3327 	 */
3328 	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3329 		iomap->type = IOMAP_UNWRITTEN;
3330 		iomap->addr = (u64) map->m_pblk << blkbits;
3331 		if (flags & IOMAP_DAX)
3332 			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
3333 	} else if (map->m_flags & EXT4_MAP_MAPPED) {
3334 		iomap->type = IOMAP_MAPPED;
3335 		iomap->addr = (u64) map->m_pblk << blkbits;
3336 		if (flags & IOMAP_DAX)
3337 			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
3338 	} else if (map->m_flags & EXT4_MAP_DELAYED) {
3339 		iomap->type = IOMAP_DELALLOC;
3340 		iomap->addr = IOMAP_NULL_ADDR;
3341 	} else {
3342 		iomap->type = IOMAP_HOLE;
3343 		iomap->addr = IOMAP_NULL_ADDR;
3344 	}
3345 }
3346 
ext4_iomap_alloc(struct inode * inode,struct ext4_map_blocks * map,unsigned int flags)3347 static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3348 			    unsigned int flags)
3349 {
3350 	handle_t *handle;
3351 	u8 blkbits = inode->i_blkbits;
3352 	int ret, dio_credits, m_flags = 0, retries = 0;
3353 
3354 	/*
3355 	 * Trim the mapping request to the maximum value that we can map at
3356 	 * once for direct I/O.
3357 	 */
3358 	if (map->m_len > DIO_MAX_BLOCKS)
3359 		map->m_len = DIO_MAX_BLOCKS;
3360 	dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3361 
3362 retry:
3363 	/*
3364 	 * Either we allocate blocks and then don't get an unwritten extent, so
3365 	 * in that case we have reserved enough credits. Or, the blocks are
3366 	 * already allocated and unwritten. In that case, the extent conversion
3367 	 * fits into the credits as well.
3368 	 */
3369 	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3370 	if (IS_ERR(handle))
3371 		return PTR_ERR(handle);
3372 
3373 	/*
3374 	 * DAX and direct I/O are the only two operations that are currently
3375 	 * supported with IOMAP_WRITE.
3376 	 */
3377 	WARN_ON(!(flags & (IOMAP_DAX | IOMAP_DIRECT)));
3378 	if (flags & IOMAP_DAX)
3379 		m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3380 	/*
3381 	 * We use i_size instead of i_disksize here because delalloc writeback
3382 	 * can complete at any point during the I/O and subsequently push the
3383 	 * i_disksize out to i_size. This could be beyond where direct I/O is
3384 	 * happening and thus expose allocated blocks to direct I/O reads.
3385 	 */
3386 	else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
3387 		m_flags = EXT4_GET_BLOCKS_CREATE;
3388 	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3389 		m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3390 
3391 	ret = ext4_map_blocks(handle, inode, map, m_flags);
3392 
3393 	/*
3394 	 * We cannot fill holes in indirect tree based inodes as that could
3395 	 * expose stale data in the case of a crash. Use the magic error code
3396 	 * to fallback to buffered I/O.
3397 	 */
3398 	if (!m_flags && !ret)
3399 		ret = -ENOTBLK;
3400 
3401 	ext4_journal_stop(handle);
3402 	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3403 		goto retry;
3404 
3405 	return ret;
3406 }
3407 
3408 
ext4_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)3409 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3410 		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3411 {
3412 	int ret;
3413 	struct ext4_map_blocks map;
3414 	u8 blkbits = inode->i_blkbits;
3415 
3416 	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3417 		return -EINVAL;
3418 
3419 	if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3420 		return -ERANGE;
3421 
3422 	/*
3423 	 * Calculate the first and last logical blocks respectively.
3424 	 */
3425 	map.m_lblk = offset >> blkbits;
3426 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3427 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3428 
3429 	if (flags & IOMAP_WRITE) {
3430 		/*
3431 		 * We check here if the blocks are already allocated, then we
3432 		 * don't need to start a journal txn and we can directly return
3433 		 * the mapping information. This could boost performance
3434 		 * especially in multi-threaded overwrite requests.
3435 		 */
3436 		if (offset + length <= i_size_read(inode)) {
3437 			ret = ext4_map_blocks(NULL, inode, &map, 0);
3438 			if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
3439 				goto out;
3440 		}
3441 		ret = ext4_iomap_alloc(inode, &map, flags);
3442 	} else {
3443 		ret = ext4_map_blocks(NULL, inode, &map, 0);
3444 	}
3445 
3446 	if (ret < 0)
3447 		return ret;
3448 out:
3449 	/*
3450 	 * When inline encryption is enabled, sometimes I/O to an encrypted file
3451 	 * has to be broken up to guarantee DUN contiguity.  Handle this by
3452 	 * limiting the length of the mapping returned.
3453 	 */
3454 	map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, map.m_len);
3455 
3456 	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
3457 
3458 	return 0;
3459 }
3460 
ext4_iomap_overwrite_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)3461 static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3462 		loff_t length, unsigned flags, struct iomap *iomap,
3463 		struct iomap *srcmap)
3464 {
3465 	int ret;
3466 
3467 	/*
3468 	 * Even for writes we don't need to allocate blocks, so just pretend
3469 	 * we are reading to save overhead of starting a transaction.
3470 	 */
3471 	flags &= ~IOMAP_WRITE;
3472 	ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3473 	WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED);
3474 	return ret;
3475 }
3476 
ext4_iomap_end(struct inode * inode,loff_t offset,loff_t length,ssize_t written,unsigned flags,struct iomap * iomap)3477 static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3478 			  ssize_t written, unsigned flags, struct iomap *iomap)
3479 {
3480 	/*
3481 	 * Check to see whether an error occurred while writing out the data to
3482 	 * the allocated blocks. If so, return the magic error code so that we
3483 	 * fallback to buffered I/O and attempt to complete the remainder of
3484 	 * the I/O. Any blocks that may have been allocated in preparation for
3485 	 * the direct I/O will be reused during buffered I/O.
3486 	 */
3487 	if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3488 		return -ENOTBLK;
3489 
3490 	return 0;
3491 }
3492 
3493 const struct iomap_ops ext4_iomap_ops = {
3494 	.iomap_begin		= ext4_iomap_begin,
3495 	.iomap_end		= ext4_iomap_end,
3496 };
3497 
3498 const struct iomap_ops ext4_iomap_overwrite_ops = {
3499 	.iomap_begin		= ext4_iomap_overwrite_begin,
3500 	.iomap_end		= ext4_iomap_end,
3501 };
3502 
ext4_iomap_begin_report(struct inode * inode,loff_t offset,loff_t length,unsigned int flags,struct iomap * iomap,struct iomap * srcmap)3503 static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3504 				   loff_t length, unsigned int flags,
3505 				   struct iomap *iomap, struct iomap *srcmap)
3506 {
3507 	int ret;
3508 	struct ext4_map_blocks map;
3509 	u8 blkbits = inode->i_blkbits;
3510 
3511 	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3512 		return -EINVAL;
3513 
3514 	if (ext4_has_inline_data(inode)) {
3515 		ret = ext4_inline_data_iomap(inode, iomap);
3516 		if (ret != -EAGAIN) {
3517 			if (ret == 0 && offset >= iomap->length)
3518 				ret = -ENOENT;
3519 			return ret;
3520 		}
3521 	}
3522 
3523 	/*
3524 	 * Calculate the first and last logical block respectively.
3525 	 */
3526 	map.m_lblk = offset >> blkbits;
3527 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3528 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3529 
3530 	/*
3531 	 * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3532 	 * So handle it here itself instead of querying ext4_map_blocks().
3533 	 * Since ext4_map_blocks() will warn about it and will return
3534 	 * -EIO error.
3535 	 */
3536 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3537 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3538 
3539 		if (offset >= sbi->s_bitmap_maxbytes) {
3540 			map.m_flags = 0;
3541 			goto set_iomap;
3542 		}
3543 	}
3544 
3545 	ret = ext4_map_blocks(NULL, inode, &map, 0);
3546 	if (ret < 0)
3547 		return ret;
3548 set_iomap:
3549 	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
3550 
3551 	return 0;
3552 }
3553 
3554 const struct iomap_ops ext4_iomap_report_ops = {
3555 	.iomap_begin = ext4_iomap_begin_report,
3556 };
3557 
3558 /*
3559  * For data=journal mode, folio should be marked dirty only when it was
3560  * writeably mapped. When that happens, it was already attached to the
3561  * transaction and marked as jbddirty (we take care of this in
3562  * ext4_page_mkwrite()). On transaction commit, we writeprotect page mappings
3563  * so we should have nothing to do here, except for the case when someone
3564  * had the page pinned and dirtied the page through this pin (e.g. by doing
3565  * direct IO to it). In that case we'd need to attach buffers here to the
3566  * transaction but we cannot due to lock ordering.  We cannot just dirty the
3567  * folio and leave attached buffers clean, because the buffers' dirty state is
3568  * "definitive".  We cannot just set the buffers dirty or jbddirty because all
3569  * the journalling code will explode.  So what we do is to mark the folio
3570  * "pending dirty" and next time ext4_writepages() is called, attach buffers
3571  * to the transaction appropriately.
3572  */
ext4_journalled_dirty_folio(struct address_space * mapping,struct folio * folio)3573 static bool ext4_journalled_dirty_folio(struct address_space *mapping,
3574 		struct folio *folio)
3575 {
3576 	WARN_ON_ONCE(!folio_buffers(folio));
3577 	if (folio_maybe_dma_pinned(folio))
3578 		folio_set_checked(folio);
3579 	return filemap_dirty_folio(mapping, folio);
3580 }
3581 
ext4_dirty_folio(struct address_space * mapping,struct folio * folio)3582 static bool ext4_dirty_folio(struct address_space *mapping, struct folio *folio)
3583 {
3584 	WARN_ON_ONCE(!folio_test_locked(folio) && !folio_test_dirty(folio));
3585 	WARN_ON_ONCE(!folio_buffers(folio));
3586 	return block_dirty_folio(mapping, folio);
3587 }
3588 
ext4_iomap_swap_activate(struct swap_info_struct * sis,struct file * file,sector_t * span)3589 static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3590 				    struct file *file, sector_t *span)
3591 {
3592 	return iomap_swapfile_activate(sis, file, span,
3593 				       &ext4_iomap_report_ops);
3594 }
3595 
3596 static const struct address_space_operations ext4_aops = {
3597 	.read_folio		= ext4_read_folio,
3598 	.readahead		= ext4_readahead,
3599 	.writepages		= ext4_writepages,
3600 	.write_begin		= ext4_write_begin,
3601 	.write_end		= ext4_write_end,
3602 	.dirty_folio		= ext4_dirty_folio,
3603 	.bmap			= ext4_bmap,
3604 	.invalidate_folio	= ext4_invalidate_folio,
3605 	.release_folio		= ext4_release_folio,
3606 	.migrate_folio		= buffer_migrate_folio,
3607 	.is_partially_uptodate  = block_is_partially_uptodate,
3608 	.error_remove_folio	= generic_error_remove_folio,
3609 	.swap_activate		= ext4_iomap_swap_activate,
3610 };
3611 
3612 static const struct address_space_operations ext4_journalled_aops = {
3613 	.read_folio		= ext4_read_folio,
3614 	.readahead		= ext4_readahead,
3615 	.writepages		= ext4_writepages,
3616 	.write_begin		= ext4_write_begin,
3617 	.write_end		= ext4_journalled_write_end,
3618 	.dirty_folio		= ext4_journalled_dirty_folio,
3619 	.bmap			= ext4_bmap,
3620 	.invalidate_folio	= ext4_journalled_invalidate_folio,
3621 	.release_folio		= ext4_release_folio,
3622 	.migrate_folio		= buffer_migrate_folio_norefs,
3623 	.is_partially_uptodate  = block_is_partially_uptodate,
3624 	.error_remove_folio	= generic_error_remove_folio,
3625 	.swap_activate		= ext4_iomap_swap_activate,
3626 };
3627 
3628 static const struct address_space_operations ext4_da_aops = {
3629 	.read_folio		= ext4_read_folio,
3630 	.readahead		= ext4_readahead,
3631 	.writepages		= ext4_writepages,
3632 	.write_begin		= ext4_da_write_begin,
3633 	.write_end		= ext4_da_write_end,
3634 	.dirty_folio		= ext4_dirty_folio,
3635 	.bmap			= ext4_bmap,
3636 	.invalidate_folio	= ext4_invalidate_folio,
3637 	.release_folio		= ext4_release_folio,
3638 	.migrate_folio		= buffer_migrate_folio,
3639 	.is_partially_uptodate  = block_is_partially_uptodate,
3640 	.error_remove_folio	= generic_error_remove_folio,
3641 	.swap_activate		= ext4_iomap_swap_activate,
3642 };
3643 
3644 static const struct address_space_operations ext4_dax_aops = {
3645 	.writepages		= ext4_dax_writepages,
3646 	.dirty_folio		= noop_dirty_folio,
3647 	.bmap			= ext4_bmap,
3648 	.swap_activate		= ext4_iomap_swap_activate,
3649 };
3650 
ext4_set_aops(struct inode * inode)3651 void ext4_set_aops(struct inode *inode)
3652 {
3653 	switch (ext4_inode_journal_mode(inode)) {
3654 	case EXT4_INODE_ORDERED_DATA_MODE:
3655 	case EXT4_INODE_WRITEBACK_DATA_MODE:
3656 		break;
3657 	case EXT4_INODE_JOURNAL_DATA_MODE:
3658 		inode->i_mapping->a_ops = &ext4_journalled_aops;
3659 		return;
3660 	default:
3661 		BUG();
3662 	}
3663 	if (IS_DAX(inode))
3664 		inode->i_mapping->a_ops = &ext4_dax_aops;
3665 	else if (test_opt(inode->i_sb, DELALLOC))
3666 		inode->i_mapping->a_ops = &ext4_da_aops;
3667 	else
3668 		inode->i_mapping->a_ops = &ext4_aops;
3669 }
3670 
3671 /*
3672  * Here we can't skip an unwritten buffer even though it usually reads zero
3673  * because it might have data in pagecache (eg, if called from ext4_zero_range,
3674  * ext4_punch_hole, etc) which needs to be properly zeroed out. Otherwise a
3675  * racing writeback can come later and flush the stale pagecache to disk.
3676  */
__ext4_block_zero_page_range(handle_t * handle,struct address_space * mapping,loff_t from,loff_t length)3677 static int __ext4_block_zero_page_range(handle_t *handle,
3678 		struct address_space *mapping, loff_t from, loff_t length)
3679 {
3680 	ext4_fsblk_t index = from >> PAGE_SHIFT;
3681 	unsigned offset = from & (PAGE_SIZE-1);
3682 	unsigned blocksize, pos;
3683 	ext4_lblk_t iblock;
3684 	struct inode *inode = mapping->host;
3685 	struct buffer_head *bh;
3686 	struct folio *folio;
3687 	int err = 0;
3688 
3689 	folio = __filemap_get_folio(mapping, from >> PAGE_SHIFT,
3690 				    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
3691 				    mapping_gfp_constraint(mapping, ~__GFP_FS));
3692 	if (IS_ERR(folio))
3693 		return PTR_ERR(folio);
3694 
3695 	blocksize = inode->i_sb->s_blocksize;
3696 
3697 	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3698 
3699 	bh = folio_buffers(folio);
3700 	if (!bh)
3701 		bh = create_empty_buffers(folio, blocksize, 0);
3702 
3703 	/* Find the buffer that contains "offset" */
3704 	pos = blocksize;
3705 	while (offset >= pos) {
3706 		bh = bh->b_this_page;
3707 		iblock++;
3708 		pos += blocksize;
3709 	}
3710 	if (buffer_freed(bh)) {
3711 		BUFFER_TRACE(bh, "freed: skip");
3712 		goto unlock;
3713 	}
3714 	if (!buffer_mapped(bh)) {
3715 		BUFFER_TRACE(bh, "unmapped");
3716 		ext4_get_block(inode, iblock, bh, 0);
3717 		/* unmapped? It's a hole - nothing to do */
3718 		if (!buffer_mapped(bh)) {
3719 			BUFFER_TRACE(bh, "still unmapped");
3720 			goto unlock;
3721 		}
3722 	}
3723 
3724 	/* Ok, it's mapped. Make sure it's up-to-date */
3725 	if (folio_test_uptodate(folio))
3726 		set_buffer_uptodate(bh);
3727 
3728 	if (!buffer_uptodate(bh)) {
3729 		err = ext4_read_bh_lock(bh, 0, true);
3730 		if (err)
3731 			goto unlock;
3732 		if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3733 			/* We expect the key to be set. */
3734 			BUG_ON(!fscrypt_has_encryption_key(inode));
3735 			err = fscrypt_decrypt_pagecache_blocks(folio,
3736 							       blocksize,
3737 							       bh_offset(bh));
3738 			if (err) {
3739 				clear_buffer_uptodate(bh);
3740 				goto unlock;
3741 			}
3742 		}
3743 	}
3744 	if (ext4_should_journal_data(inode)) {
3745 		BUFFER_TRACE(bh, "get write access");
3746 		err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
3747 						    EXT4_JTR_NONE);
3748 		if (err)
3749 			goto unlock;
3750 	}
3751 	folio_zero_range(folio, offset, length);
3752 	BUFFER_TRACE(bh, "zeroed end of block");
3753 
3754 	if (ext4_should_journal_data(inode)) {
3755 		err = ext4_dirty_journalled_data(handle, bh);
3756 	} else {
3757 		err = 0;
3758 		mark_buffer_dirty(bh);
3759 		if (ext4_should_order_data(inode))
3760 			err = ext4_jbd2_inode_add_write(handle, inode, from,
3761 					length);
3762 	}
3763 
3764 unlock:
3765 	folio_unlock(folio);
3766 	folio_put(folio);
3767 	return err;
3768 }
3769 
3770 /*
3771  * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3772  * starting from file offset 'from'.  The range to be zero'd must
3773  * be contained with in one block.  If the specified range exceeds
3774  * the end of the block it will be shortened to end of the block
3775  * that corresponds to 'from'
3776  */
ext4_block_zero_page_range(handle_t * handle,struct address_space * mapping,loff_t from,loff_t length)3777 static int ext4_block_zero_page_range(handle_t *handle,
3778 		struct address_space *mapping, loff_t from, loff_t length)
3779 {
3780 	struct inode *inode = mapping->host;
3781 	unsigned offset = from & (PAGE_SIZE-1);
3782 	unsigned blocksize = inode->i_sb->s_blocksize;
3783 	unsigned max = blocksize - (offset & (blocksize - 1));
3784 
3785 	/*
3786 	 * correct length if it does not fall between
3787 	 * 'from' and the end of the block
3788 	 */
3789 	if (length > max || length < 0)
3790 		length = max;
3791 
3792 	if (IS_DAX(inode)) {
3793 		return dax_zero_range(inode, from, length, NULL,
3794 				      &ext4_iomap_ops);
3795 	}
3796 	return __ext4_block_zero_page_range(handle, mapping, from, length);
3797 }
3798 
3799 /*
3800  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3801  * up to the end of the block which corresponds to `from'.
3802  * This required during truncate. We need to physically zero the tail end
3803  * of that block so it doesn't yield old data if the file is later grown.
3804  */
ext4_block_truncate_page(handle_t * handle,struct address_space * mapping,loff_t from)3805 static int ext4_block_truncate_page(handle_t *handle,
3806 		struct address_space *mapping, loff_t from)
3807 {
3808 	unsigned offset = from & (PAGE_SIZE-1);
3809 	unsigned length;
3810 	unsigned blocksize;
3811 	struct inode *inode = mapping->host;
3812 
3813 	/* If we are processing an encrypted inode during orphan list handling */
3814 	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3815 		return 0;
3816 
3817 	blocksize = inode->i_sb->s_blocksize;
3818 	length = blocksize - (offset & (blocksize - 1));
3819 
3820 	return ext4_block_zero_page_range(handle, mapping, from, length);
3821 }
3822 
ext4_zero_partial_blocks(handle_t * handle,struct inode * inode,loff_t lstart,loff_t length)3823 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3824 			     loff_t lstart, loff_t length)
3825 {
3826 	struct super_block *sb = inode->i_sb;
3827 	struct address_space *mapping = inode->i_mapping;
3828 	unsigned partial_start, partial_end;
3829 	ext4_fsblk_t start, end;
3830 	loff_t byte_end = (lstart + length - 1);
3831 	int err = 0;
3832 
3833 	partial_start = lstart & (sb->s_blocksize - 1);
3834 	partial_end = byte_end & (sb->s_blocksize - 1);
3835 
3836 	start = lstart >> sb->s_blocksize_bits;
3837 	end = byte_end >> sb->s_blocksize_bits;
3838 
3839 	/* Handle partial zero within the single block */
3840 	if (start == end &&
3841 	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
3842 		err = ext4_block_zero_page_range(handle, mapping,
3843 						 lstart, length);
3844 		return err;
3845 	}
3846 	/* Handle partial zero out on the start of the range */
3847 	if (partial_start) {
3848 		err = ext4_block_zero_page_range(handle, mapping,
3849 						 lstart, sb->s_blocksize);
3850 		if (err)
3851 			return err;
3852 	}
3853 	/* Handle partial zero out on the end of the range */
3854 	if (partial_end != sb->s_blocksize - 1)
3855 		err = ext4_block_zero_page_range(handle, mapping,
3856 						 byte_end - partial_end,
3857 						 partial_end + 1);
3858 	return err;
3859 }
3860 
ext4_can_truncate(struct inode * inode)3861 int ext4_can_truncate(struct inode *inode)
3862 {
3863 	if (S_ISREG(inode->i_mode))
3864 		return 1;
3865 	if (S_ISDIR(inode->i_mode))
3866 		return 1;
3867 	if (S_ISLNK(inode->i_mode))
3868 		return !ext4_inode_is_fast_symlink(inode);
3869 	return 0;
3870 }
3871 
3872 /*
3873  * We have to make sure i_disksize gets properly updated before we truncate
3874  * page cache due to hole punching or zero range. Otherwise i_disksize update
3875  * can get lost as it may have been postponed to submission of writeback but
3876  * that will never happen after we truncate page cache.
3877  */
ext4_update_disksize_before_punch(struct inode * inode,loff_t offset,loff_t len)3878 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3879 				      loff_t len)
3880 {
3881 	handle_t *handle;
3882 	int ret;
3883 
3884 	loff_t size = i_size_read(inode);
3885 
3886 	WARN_ON(!inode_is_locked(inode));
3887 	if (offset > size || offset + len < size)
3888 		return 0;
3889 
3890 	if (EXT4_I(inode)->i_disksize >= size)
3891 		return 0;
3892 
3893 	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3894 	if (IS_ERR(handle))
3895 		return PTR_ERR(handle);
3896 	ext4_update_i_disksize(inode, size);
3897 	ret = ext4_mark_inode_dirty(handle, inode);
3898 	ext4_journal_stop(handle);
3899 
3900 	return ret;
3901 }
3902 
ext4_wait_dax_page(struct inode * inode)3903 static void ext4_wait_dax_page(struct inode *inode)
3904 {
3905 	filemap_invalidate_unlock(inode->i_mapping);
3906 	schedule();
3907 	filemap_invalidate_lock(inode->i_mapping);
3908 }
3909 
ext4_break_layouts(struct inode * inode)3910 int ext4_break_layouts(struct inode *inode)
3911 {
3912 	struct page *page;
3913 	int error;
3914 
3915 	if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock)))
3916 		return -EINVAL;
3917 
3918 	do {
3919 		page = dax_layout_busy_page(inode->i_mapping);
3920 		if (!page)
3921 			return 0;
3922 
3923 		error = ___wait_var_event(&page->_refcount,
3924 				atomic_read(&page->_refcount) == 1,
3925 				TASK_INTERRUPTIBLE, 0, 0,
3926 				ext4_wait_dax_page(inode));
3927 	} while (error == 0);
3928 
3929 	return error;
3930 }
3931 
3932 /*
3933  * ext4_punch_hole: punches a hole in a file by releasing the blocks
3934  * associated with the given offset and length
3935  *
3936  * @inode:  File inode
3937  * @offset: The offset where the hole will begin
3938  * @len:    The length of the hole
3939  *
3940  * Returns: 0 on success or negative on failure
3941  */
3942 
ext4_punch_hole(struct file * file,loff_t offset,loff_t length)3943 int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
3944 {
3945 	struct inode *inode = file_inode(file);
3946 	struct super_block *sb = inode->i_sb;
3947 	ext4_lblk_t first_block, stop_block;
3948 	struct address_space *mapping = inode->i_mapping;
3949 	loff_t first_block_offset, last_block_offset, max_length;
3950 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3951 	handle_t *handle;
3952 	unsigned int credits;
3953 	int ret = 0, ret2 = 0;
3954 
3955 	trace_ext4_punch_hole(inode, offset, length, 0);
3956 
3957 	/*
3958 	 * Write out all dirty pages to avoid race conditions
3959 	 * Then release them.
3960 	 */
3961 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3962 		ret = filemap_write_and_wait_range(mapping, offset,
3963 						   offset + length - 1);
3964 		if (ret)
3965 			return ret;
3966 	}
3967 
3968 	inode_lock(inode);
3969 
3970 	/* No need to punch hole beyond i_size */
3971 	if (offset >= inode->i_size)
3972 		goto out_mutex;
3973 
3974 	/*
3975 	 * If the hole extends beyond i_size, set the hole
3976 	 * to end after the page that contains i_size
3977 	 */
3978 	if (offset + length > inode->i_size) {
3979 		length = inode->i_size +
3980 		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
3981 		   offset;
3982 	}
3983 
3984 	/*
3985 	 * For punch hole the length + offset needs to be within one block
3986 	 * before last range. Adjust the length if it goes beyond that limit.
3987 	 */
3988 	max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize;
3989 	if (offset + length > max_length)
3990 		length = max_length - offset;
3991 
3992 	if (offset & (sb->s_blocksize - 1) ||
3993 	    (offset + length) & (sb->s_blocksize - 1)) {
3994 		/*
3995 		 * Attach jinode to inode for jbd2 if we do any zeroing of
3996 		 * partial block
3997 		 */
3998 		ret = ext4_inode_attach_jinode(inode);
3999 		if (ret < 0)
4000 			goto out_mutex;
4001 
4002 	}
4003 
4004 	/* Wait all existing dio workers, newcomers will block on i_rwsem */
4005 	inode_dio_wait(inode);
4006 
4007 	ret = file_modified(file);
4008 	if (ret)
4009 		goto out_mutex;
4010 
4011 	/*
4012 	 * Prevent page faults from reinstantiating pages we have released from
4013 	 * page cache.
4014 	 */
4015 	filemap_invalidate_lock(mapping);
4016 
4017 	ret = ext4_break_layouts(inode);
4018 	if (ret)
4019 		goto out_dio;
4020 
4021 	first_block_offset = round_up(offset, sb->s_blocksize);
4022 	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
4023 
4024 	/* Now release the pages and zero block aligned part of pages*/
4025 	if (last_block_offset > first_block_offset) {
4026 		ret = ext4_update_disksize_before_punch(inode, offset, length);
4027 		if (ret)
4028 			goto out_dio;
4029 		truncate_pagecache_range(inode, first_block_offset,
4030 					 last_block_offset);
4031 	}
4032 
4033 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4034 		credits = ext4_writepage_trans_blocks(inode);
4035 	else
4036 		credits = ext4_blocks_for_truncate(inode);
4037 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4038 	if (IS_ERR(handle)) {
4039 		ret = PTR_ERR(handle);
4040 		ext4_std_error(sb, ret);
4041 		goto out_dio;
4042 	}
4043 
4044 	ret = ext4_zero_partial_blocks(handle, inode, offset,
4045 				       length);
4046 	if (ret)
4047 		goto out_stop;
4048 
4049 	first_block = (offset + sb->s_blocksize - 1) >>
4050 		EXT4_BLOCK_SIZE_BITS(sb);
4051 	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4052 
4053 	/* If there are blocks to remove, do it */
4054 	if (stop_block > first_block) {
4055 		ext4_lblk_t hole_len = stop_block - first_block;
4056 
4057 		down_write(&EXT4_I(inode)->i_data_sem);
4058 		ext4_discard_preallocations(inode);
4059 
4060 		ext4_es_remove_extent(inode, first_block, hole_len);
4061 
4062 		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4063 			ret = ext4_ext_remove_space(inode, first_block,
4064 						    stop_block - 1);
4065 		else
4066 			ret = ext4_ind_remove_space(handle, inode, first_block,
4067 						    stop_block);
4068 
4069 		ext4_es_insert_extent(inode, first_block, hole_len, ~0,
4070 				      EXTENT_STATUS_HOLE);
4071 		up_write(&EXT4_I(inode)->i_data_sem);
4072 	}
4073 	ext4_fc_track_range(handle, inode, first_block, stop_block);
4074 	if (IS_SYNC(inode))
4075 		ext4_handle_sync(handle);
4076 
4077 	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
4078 	ret2 = ext4_mark_inode_dirty(handle, inode);
4079 	if (unlikely(ret2))
4080 		ret = ret2;
4081 	if (ret >= 0)
4082 		ext4_update_inode_fsync_trans(handle, inode, 1);
4083 out_stop:
4084 	ext4_journal_stop(handle);
4085 out_dio:
4086 	filemap_invalidate_unlock(mapping);
4087 out_mutex:
4088 	inode_unlock(inode);
4089 	return ret;
4090 }
4091 
ext4_inode_attach_jinode(struct inode * inode)4092 int ext4_inode_attach_jinode(struct inode *inode)
4093 {
4094 	struct ext4_inode_info *ei = EXT4_I(inode);
4095 	struct jbd2_inode *jinode;
4096 
4097 	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4098 		return 0;
4099 
4100 	jinode = jbd2_alloc_inode(GFP_KERNEL);
4101 	spin_lock(&inode->i_lock);
4102 	if (!ei->jinode) {
4103 		if (!jinode) {
4104 			spin_unlock(&inode->i_lock);
4105 			return -ENOMEM;
4106 		}
4107 		ei->jinode = jinode;
4108 		jbd2_journal_init_jbd_inode(ei->jinode, inode);
4109 		jinode = NULL;
4110 	}
4111 	spin_unlock(&inode->i_lock);
4112 	if (unlikely(jinode != NULL))
4113 		jbd2_free_inode(jinode);
4114 	return 0;
4115 }
4116 
4117 /*
4118  * ext4_truncate()
4119  *
4120  * We block out ext4_get_block() block instantiations across the entire
4121  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4122  * simultaneously on behalf of the same inode.
4123  *
4124  * As we work through the truncate and commit bits of it to the journal there
4125  * is one core, guiding principle: the file's tree must always be consistent on
4126  * disk.  We must be able to restart the truncate after a crash.
4127  *
4128  * The file's tree may be transiently inconsistent in memory (although it
4129  * probably isn't), but whenever we close off and commit a journal transaction,
4130  * the contents of (the filesystem + the journal) must be consistent and
4131  * restartable.  It's pretty simple, really: bottom up, right to left (although
4132  * left-to-right works OK too).
4133  *
4134  * Note that at recovery time, journal replay occurs *before* the restart of
4135  * truncate against the orphan inode list.
4136  *
4137  * The committed inode has the new, desired i_size (which is the same as
4138  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4139  * that this inode's truncate did not complete and it will again call
4140  * ext4_truncate() to have another go.  So there will be instantiated blocks
4141  * to the right of the truncation point in a crashed ext4 filesystem.  But
4142  * that's fine - as long as they are linked from the inode, the post-crash
4143  * ext4_truncate() run will find them and release them.
4144  */
ext4_truncate(struct inode * inode)4145 int ext4_truncate(struct inode *inode)
4146 {
4147 	struct ext4_inode_info *ei = EXT4_I(inode);
4148 	unsigned int credits;
4149 	int err = 0, err2;
4150 	handle_t *handle;
4151 	struct address_space *mapping = inode->i_mapping;
4152 
4153 	/*
4154 	 * There is a possibility that we're either freeing the inode
4155 	 * or it's a completely new inode. In those cases we might not
4156 	 * have i_rwsem locked because it's not necessary.
4157 	 */
4158 	if (!(inode->i_state & (I_NEW|I_FREEING)))
4159 		WARN_ON(!inode_is_locked(inode));
4160 	trace_ext4_truncate_enter(inode);
4161 
4162 	if (!ext4_can_truncate(inode))
4163 		goto out_trace;
4164 
4165 	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4166 		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4167 
4168 	if (ext4_has_inline_data(inode)) {
4169 		int has_inline = 1;
4170 
4171 		err = ext4_inline_data_truncate(inode, &has_inline);
4172 		if (err || has_inline)
4173 			goto out_trace;
4174 	}
4175 
4176 	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
4177 	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4178 		err = ext4_inode_attach_jinode(inode);
4179 		if (err)
4180 			goto out_trace;
4181 	}
4182 
4183 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4184 		credits = ext4_writepage_trans_blocks(inode);
4185 	else
4186 		credits = ext4_blocks_for_truncate(inode);
4187 
4188 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4189 	if (IS_ERR(handle)) {
4190 		err = PTR_ERR(handle);
4191 		goto out_trace;
4192 	}
4193 
4194 	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4195 		ext4_block_truncate_page(handle, mapping, inode->i_size);
4196 
4197 	/*
4198 	 * We add the inode to the orphan list, so that if this
4199 	 * truncate spans multiple transactions, and we crash, we will
4200 	 * resume the truncate when the filesystem recovers.  It also
4201 	 * marks the inode dirty, to catch the new size.
4202 	 *
4203 	 * Implication: the file must always be in a sane, consistent
4204 	 * truncatable state while each transaction commits.
4205 	 */
4206 	err = ext4_orphan_add(handle, inode);
4207 	if (err)
4208 		goto out_stop;
4209 
4210 	down_write(&EXT4_I(inode)->i_data_sem);
4211 
4212 	ext4_discard_preallocations(inode);
4213 
4214 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4215 		err = ext4_ext_truncate(handle, inode);
4216 	else
4217 		ext4_ind_truncate(handle, inode);
4218 
4219 	up_write(&ei->i_data_sem);
4220 	if (err)
4221 		goto out_stop;
4222 
4223 	if (IS_SYNC(inode))
4224 		ext4_handle_sync(handle);
4225 
4226 out_stop:
4227 	/*
4228 	 * If this was a simple ftruncate() and the file will remain alive,
4229 	 * then we need to clear up the orphan record which we created above.
4230 	 * However, if this was a real unlink then we were called by
4231 	 * ext4_evict_inode(), and we allow that function to clean up the
4232 	 * orphan info for us.
4233 	 */
4234 	if (inode->i_nlink)
4235 		ext4_orphan_del(handle, inode);
4236 
4237 	inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
4238 	err2 = ext4_mark_inode_dirty(handle, inode);
4239 	if (unlikely(err2 && !err))
4240 		err = err2;
4241 	ext4_journal_stop(handle);
4242 
4243 out_trace:
4244 	trace_ext4_truncate_exit(inode);
4245 	return err;
4246 }
4247 
ext4_inode_peek_iversion(const struct inode * inode)4248 static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4249 {
4250 	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4251 		return inode_peek_iversion_raw(inode);
4252 	else
4253 		return inode_peek_iversion(inode);
4254 }
4255 
ext4_inode_blocks_set(struct ext4_inode * raw_inode,struct ext4_inode_info * ei)4256 static int ext4_inode_blocks_set(struct ext4_inode *raw_inode,
4257 				 struct ext4_inode_info *ei)
4258 {
4259 	struct inode *inode = &(ei->vfs_inode);
4260 	u64 i_blocks = READ_ONCE(inode->i_blocks);
4261 	struct super_block *sb = inode->i_sb;
4262 
4263 	if (i_blocks <= ~0U) {
4264 		/*
4265 		 * i_blocks can be represented in a 32 bit variable
4266 		 * as multiple of 512 bytes
4267 		 */
4268 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4269 		raw_inode->i_blocks_high = 0;
4270 		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4271 		return 0;
4272 	}
4273 
4274 	/*
4275 	 * This should never happen since sb->s_maxbytes should not have
4276 	 * allowed this, sb->s_maxbytes was set according to the huge_file
4277 	 * feature in ext4_fill_super().
4278 	 */
4279 	if (!ext4_has_feature_huge_file(sb))
4280 		return -EFSCORRUPTED;
4281 
4282 	if (i_blocks <= 0xffffffffffffULL) {
4283 		/*
4284 		 * i_blocks can be represented in a 48 bit variable
4285 		 * as multiple of 512 bytes
4286 		 */
4287 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4288 		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4289 		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4290 	} else {
4291 		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4292 		/* i_block is stored in file system block size */
4293 		i_blocks = i_blocks >> (inode->i_blkbits - 9);
4294 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4295 		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4296 	}
4297 	return 0;
4298 }
4299 
ext4_fill_raw_inode(struct inode * inode,struct ext4_inode * raw_inode)4300 static int ext4_fill_raw_inode(struct inode *inode, struct ext4_inode *raw_inode)
4301 {
4302 	struct ext4_inode_info *ei = EXT4_I(inode);
4303 	uid_t i_uid;
4304 	gid_t i_gid;
4305 	projid_t i_projid;
4306 	int block;
4307 	int err;
4308 
4309 	err = ext4_inode_blocks_set(raw_inode, ei);
4310 
4311 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4312 	i_uid = i_uid_read(inode);
4313 	i_gid = i_gid_read(inode);
4314 	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4315 	if (!(test_opt(inode->i_sb, NO_UID32))) {
4316 		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4317 		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4318 		/*
4319 		 * Fix up interoperability with old kernels. Otherwise,
4320 		 * old inodes get re-used with the upper 16 bits of the
4321 		 * uid/gid intact.
4322 		 */
4323 		if (ei->i_dtime && list_empty(&ei->i_orphan)) {
4324 			raw_inode->i_uid_high = 0;
4325 			raw_inode->i_gid_high = 0;
4326 		} else {
4327 			raw_inode->i_uid_high =
4328 				cpu_to_le16(high_16_bits(i_uid));
4329 			raw_inode->i_gid_high =
4330 				cpu_to_le16(high_16_bits(i_gid));
4331 		}
4332 	} else {
4333 		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4334 		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4335 		raw_inode->i_uid_high = 0;
4336 		raw_inode->i_gid_high = 0;
4337 	}
4338 	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4339 
4340 	EXT4_INODE_SET_CTIME(inode, raw_inode);
4341 	EXT4_INODE_SET_MTIME(inode, raw_inode);
4342 	EXT4_INODE_SET_ATIME(inode, raw_inode);
4343 	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4344 
4345 	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4346 	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4347 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4348 		raw_inode->i_file_acl_high =
4349 			cpu_to_le16(ei->i_file_acl >> 32);
4350 	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4351 	ext4_isize_set(raw_inode, ei->i_disksize);
4352 
4353 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4354 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4355 		if (old_valid_dev(inode->i_rdev)) {
4356 			raw_inode->i_block[0] =
4357 				cpu_to_le32(old_encode_dev(inode->i_rdev));
4358 			raw_inode->i_block[1] = 0;
4359 		} else {
4360 			raw_inode->i_block[0] = 0;
4361 			raw_inode->i_block[1] =
4362 				cpu_to_le32(new_encode_dev(inode->i_rdev));
4363 			raw_inode->i_block[2] = 0;
4364 		}
4365 	} else if (!ext4_has_inline_data(inode)) {
4366 		for (block = 0; block < EXT4_N_BLOCKS; block++)
4367 			raw_inode->i_block[block] = ei->i_data[block];
4368 	}
4369 
4370 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4371 		u64 ivers = ext4_inode_peek_iversion(inode);
4372 
4373 		raw_inode->i_disk_version = cpu_to_le32(ivers);
4374 		if (ei->i_extra_isize) {
4375 			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4376 				raw_inode->i_version_hi =
4377 					cpu_to_le32(ivers >> 32);
4378 			raw_inode->i_extra_isize =
4379 				cpu_to_le16(ei->i_extra_isize);
4380 		}
4381 	}
4382 
4383 	if (i_projid != EXT4_DEF_PROJID &&
4384 	    !ext4_has_feature_project(inode->i_sb))
4385 		err = err ?: -EFSCORRUPTED;
4386 
4387 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4388 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4389 		raw_inode->i_projid = cpu_to_le32(i_projid);
4390 
4391 	ext4_inode_csum_set(inode, raw_inode, ei);
4392 	return err;
4393 }
4394 
4395 /*
4396  * ext4_get_inode_loc returns with an extra refcount against the inode's
4397  * underlying buffer_head on success. If we pass 'inode' and it does not
4398  * have in-inode xattr, we have all inode data in memory that is needed
4399  * to recreate the on-disk version of this inode.
4400  */
__ext4_get_inode_loc(struct super_block * sb,unsigned long ino,struct inode * inode,struct ext4_iloc * iloc,ext4_fsblk_t * ret_block)4401 static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
4402 				struct inode *inode, struct ext4_iloc *iloc,
4403 				ext4_fsblk_t *ret_block)
4404 {
4405 	struct ext4_group_desc	*gdp;
4406 	struct buffer_head	*bh;
4407 	ext4_fsblk_t		block;
4408 	struct blk_plug		plug;
4409 	int			inodes_per_block, inode_offset;
4410 
4411 	iloc->bh = NULL;
4412 	if (ino < EXT4_ROOT_INO ||
4413 	    ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4414 		return -EFSCORRUPTED;
4415 
4416 	iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
4417 	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4418 	if (!gdp)
4419 		return -EIO;
4420 
4421 	/*
4422 	 * Figure out the offset within the block group inode table
4423 	 */
4424 	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4425 	inode_offset = ((ino - 1) %
4426 			EXT4_INODES_PER_GROUP(sb));
4427 	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4428 
4429 	block = ext4_inode_table(sb, gdp);
4430 	if ((block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) ||
4431 	    (block >= ext4_blocks_count(EXT4_SB(sb)->s_es))) {
4432 		ext4_error(sb, "Invalid inode table block %llu in "
4433 			   "block_group %u", block, iloc->block_group);
4434 		return -EFSCORRUPTED;
4435 	}
4436 	block += (inode_offset / inodes_per_block);
4437 
4438 	bh = sb_getblk(sb, block);
4439 	if (unlikely(!bh))
4440 		return -ENOMEM;
4441 	if (ext4_buffer_uptodate(bh))
4442 		goto has_buffer;
4443 
4444 	lock_buffer(bh);
4445 	if (ext4_buffer_uptodate(bh)) {
4446 		/* Someone brought it uptodate while we waited */
4447 		unlock_buffer(bh);
4448 		goto has_buffer;
4449 	}
4450 
4451 	/*
4452 	 * If we have all information of the inode in memory and this
4453 	 * is the only valid inode in the block, we need not read the
4454 	 * block.
4455 	 */
4456 	if (inode && !ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4457 		struct buffer_head *bitmap_bh;
4458 		int i, start;
4459 
4460 		start = inode_offset & ~(inodes_per_block - 1);
4461 
4462 		/* Is the inode bitmap in cache? */
4463 		bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4464 		if (unlikely(!bitmap_bh))
4465 			goto make_io;
4466 
4467 		/*
4468 		 * If the inode bitmap isn't in cache then the
4469 		 * optimisation may end up performing two reads instead
4470 		 * of one, so skip it.
4471 		 */
4472 		if (!buffer_uptodate(bitmap_bh)) {
4473 			brelse(bitmap_bh);
4474 			goto make_io;
4475 		}
4476 		for (i = start; i < start + inodes_per_block; i++) {
4477 			if (i == inode_offset)
4478 				continue;
4479 			if (ext4_test_bit(i, bitmap_bh->b_data))
4480 				break;
4481 		}
4482 		brelse(bitmap_bh);
4483 		if (i == start + inodes_per_block) {
4484 			struct ext4_inode *raw_inode =
4485 				(struct ext4_inode *) (bh->b_data + iloc->offset);
4486 
4487 			/* all other inodes are free, so skip I/O */
4488 			memset(bh->b_data, 0, bh->b_size);
4489 			if (!ext4_test_inode_state(inode, EXT4_STATE_NEW))
4490 				ext4_fill_raw_inode(inode, raw_inode);
4491 			set_buffer_uptodate(bh);
4492 			unlock_buffer(bh);
4493 			goto has_buffer;
4494 		}
4495 	}
4496 
4497 make_io:
4498 	/*
4499 	 * If we need to do any I/O, try to pre-readahead extra
4500 	 * blocks from the inode table.
4501 	 */
4502 	blk_start_plug(&plug);
4503 	if (EXT4_SB(sb)->s_inode_readahead_blks) {
4504 		ext4_fsblk_t b, end, table;
4505 		unsigned num;
4506 		__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4507 
4508 		table = ext4_inode_table(sb, gdp);
4509 		/* s_inode_readahead_blks is always a power of 2 */
4510 		b = block & ~((ext4_fsblk_t) ra_blks - 1);
4511 		if (table > b)
4512 			b = table;
4513 		end = b + ra_blks;
4514 		num = EXT4_INODES_PER_GROUP(sb);
4515 		if (ext4_has_group_desc_csum(sb))
4516 			num -= ext4_itable_unused_count(sb, gdp);
4517 		table += num / inodes_per_block;
4518 		if (end > table)
4519 			end = table;
4520 		while (b <= end)
4521 			ext4_sb_breadahead_unmovable(sb, b++);
4522 	}
4523 
4524 	/*
4525 	 * There are other valid inodes in the buffer, this inode
4526 	 * has in-inode xattrs, or we don't have this inode in memory.
4527 	 * Read the block from disk.
4528 	 */
4529 	trace_ext4_load_inode(sb, ino);
4530 	ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
4531 	blk_finish_plug(&plug);
4532 	wait_on_buffer(bh);
4533 	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
4534 	if (!buffer_uptodate(bh)) {
4535 		if (ret_block)
4536 			*ret_block = block;
4537 		brelse(bh);
4538 		return -EIO;
4539 	}
4540 has_buffer:
4541 	iloc->bh = bh;
4542 	return 0;
4543 }
4544 
__ext4_get_inode_loc_noinmem(struct inode * inode,struct ext4_iloc * iloc)4545 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4546 					struct ext4_iloc *iloc)
4547 {
4548 	ext4_fsblk_t err_blk = 0;
4549 	int ret;
4550 
4551 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, NULL, iloc,
4552 					&err_blk);
4553 
4554 	if (ret == -EIO)
4555 		ext4_error_inode_block(inode, err_blk, EIO,
4556 					"unable to read itable block");
4557 
4558 	return ret;
4559 }
4560 
ext4_get_inode_loc(struct inode * inode,struct ext4_iloc * iloc)4561 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4562 {
4563 	ext4_fsblk_t err_blk = 0;
4564 	int ret;
4565 
4566 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, inode, iloc,
4567 					&err_blk);
4568 
4569 	if (ret == -EIO)
4570 		ext4_error_inode_block(inode, err_blk, EIO,
4571 					"unable to read itable block");
4572 
4573 	return ret;
4574 }
4575 
4576 
ext4_get_fc_inode_loc(struct super_block * sb,unsigned long ino,struct ext4_iloc * iloc)4577 int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
4578 			  struct ext4_iloc *iloc)
4579 {
4580 	return __ext4_get_inode_loc(sb, ino, NULL, iloc, NULL);
4581 }
4582 
ext4_should_enable_dax(struct inode * inode)4583 static bool ext4_should_enable_dax(struct inode *inode)
4584 {
4585 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4586 
4587 	if (test_opt2(inode->i_sb, DAX_NEVER))
4588 		return false;
4589 	if (!S_ISREG(inode->i_mode))
4590 		return false;
4591 	if (ext4_should_journal_data(inode))
4592 		return false;
4593 	if (ext4_has_inline_data(inode))
4594 		return false;
4595 	if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4596 		return false;
4597 	if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4598 		return false;
4599 	if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4600 		return false;
4601 	if (test_opt(inode->i_sb, DAX_ALWAYS))
4602 		return true;
4603 
4604 	return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4605 }
4606 
ext4_set_inode_flags(struct inode * inode,bool init)4607 void ext4_set_inode_flags(struct inode *inode, bool init)
4608 {
4609 	unsigned int flags = EXT4_I(inode)->i_flags;
4610 	unsigned int new_fl = 0;
4611 
4612 	WARN_ON_ONCE(IS_DAX(inode) && init);
4613 
4614 	if (flags & EXT4_SYNC_FL)
4615 		new_fl |= S_SYNC;
4616 	if (flags & EXT4_APPEND_FL)
4617 		new_fl |= S_APPEND;
4618 	if (flags & EXT4_IMMUTABLE_FL)
4619 		new_fl |= S_IMMUTABLE;
4620 	if (flags & EXT4_NOATIME_FL)
4621 		new_fl |= S_NOATIME;
4622 	if (flags & EXT4_DIRSYNC_FL)
4623 		new_fl |= S_DIRSYNC;
4624 
4625 	/* Because of the way inode_set_flags() works we must preserve S_DAX
4626 	 * here if already set. */
4627 	new_fl |= (inode->i_flags & S_DAX);
4628 	if (init && ext4_should_enable_dax(inode))
4629 		new_fl |= S_DAX;
4630 
4631 	if (flags & EXT4_ENCRYPT_FL)
4632 		new_fl |= S_ENCRYPTED;
4633 	if (flags & EXT4_CASEFOLD_FL)
4634 		new_fl |= S_CASEFOLD;
4635 	if (flags & EXT4_VERITY_FL)
4636 		new_fl |= S_VERITY;
4637 	inode_set_flags(inode, new_fl,
4638 			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4639 			S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4640 }
4641 
ext4_inode_blocks(struct ext4_inode * raw_inode,struct ext4_inode_info * ei)4642 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4643 				  struct ext4_inode_info *ei)
4644 {
4645 	blkcnt_t i_blocks ;
4646 	struct inode *inode = &(ei->vfs_inode);
4647 	struct super_block *sb = inode->i_sb;
4648 
4649 	if (ext4_has_feature_huge_file(sb)) {
4650 		/* we are using combined 48 bit field */
4651 		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4652 					le32_to_cpu(raw_inode->i_blocks_lo);
4653 		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4654 			/* i_blocks represent file system block size */
4655 			return i_blocks  << (inode->i_blkbits - 9);
4656 		} else {
4657 			return i_blocks;
4658 		}
4659 	} else {
4660 		return le32_to_cpu(raw_inode->i_blocks_lo);
4661 	}
4662 }
4663 
ext4_iget_extra_inode(struct inode * inode,struct ext4_inode * raw_inode,struct ext4_inode_info * ei)4664 static inline int ext4_iget_extra_inode(struct inode *inode,
4665 					 struct ext4_inode *raw_inode,
4666 					 struct ext4_inode_info *ei)
4667 {
4668 	__le32 *magic = (void *)raw_inode +
4669 			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4670 
4671 	if (EXT4_INODE_HAS_XATTR_SPACE(inode)  &&
4672 	    *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4673 		int err;
4674 
4675 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4676 		err = ext4_find_inline_data_nolock(inode);
4677 		if (!err && ext4_has_inline_data(inode))
4678 			ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
4679 		return err;
4680 	} else
4681 		EXT4_I(inode)->i_inline_off = 0;
4682 	return 0;
4683 }
4684 
ext4_get_projid(struct inode * inode,kprojid_t * projid)4685 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4686 {
4687 	if (!ext4_has_feature_project(inode->i_sb))
4688 		return -EOPNOTSUPP;
4689 	*projid = EXT4_I(inode)->i_projid;
4690 	return 0;
4691 }
4692 
4693 /*
4694  * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4695  * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4696  * set.
4697  */
ext4_inode_set_iversion_queried(struct inode * inode,u64 val)4698 static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4699 {
4700 	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4701 		inode_set_iversion_raw(inode, val);
4702 	else
4703 		inode_set_iversion_queried(inode, val);
4704 }
4705 
check_igot_inode(struct inode * inode,ext4_iget_flags flags)4706 static const char *check_igot_inode(struct inode *inode, ext4_iget_flags flags)
4707 
4708 {
4709 	if (flags & EXT4_IGET_EA_INODE) {
4710 		if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4711 			return "missing EA_INODE flag";
4712 		if (ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
4713 		    EXT4_I(inode)->i_file_acl)
4714 			return "ea_inode with extended attributes";
4715 	} else {
4716 		if ((EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4717 			return "unexpected EA_INODE flag";
4718 	}
4719 	if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD))
4720 		return "unexpected bad inode w/o EXT4_IGET_BAD";
4721 	return NULL;
4722 }
4723 
__ext4_iget(struct super_block * sb,unsigned long ino,ext4_iget_flags flags,const char * function,unsigned int line)4724 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4725 			  ext4_iget_flags flags, const char *function,
4726 			  unsigned int line)
4727 {
4728 	struct ext4_iloc iloc;
4729 	struct ext4_inode *raw_inode;
4730 	struct ext4_inode_info *ei;
4731 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4732 	struct inode *inode;
4733 	const char *err_str;
4734 	journal_t *journal = EXT4_SB(sb)->s_journal;
4735 	long ret;
4736 	loff_t size;
4737 	int block;
4738 	uid_t i_uid;
4739 	gid_t i_gid;
4740 	projid_t i_projid;
4741 
4742 	if ((!(flags & EXT4_IGET_SPECIAL) &&
4743 	     ((ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) ||
4744 	      ino == le32_to_cpu(es->s_usr_quota_inum) ||
4745 	      ino == le32_to_cpu(es->s_grp_quota_inum) ||
4746 	      ino == le32_to_cpu(es->s_prj_quota_inum) ||
4747 	      ino == le32_to_cpu(es->s_orphan_file_inum))) ||
4748 	    (ino < EXT4_ROOT_INO) ||
4749 	    (ino > le32_to_cpu(es->s_inodes_count))) {
4750 		if (flags & EXT4_IGET_HANDLE)
4751 			return ERR_PTR(-ESTALE);
4752 		__ext4_error(sb, function, line, false, EFSCORRUPTED, 0,
4753 			     "inode #%lu: comm %s: iget: illegal inode #",
4754 			     ino, current->comm);
4755 		return ERR_PTR(-EFSCORRUPTED);
4756 	}
4757 
4758 	inode = iget_locked(sb, ino);
4759 	if (!inode)
4760 		return ERR_PTR(-ENOMEM);
4761 	if (!(inode->i_state & I_NEW)) {
4762 		if ((err_str = check_igot_inode(inode, flags)) != NULL) {
4763 			ext4_error_inode(inode, function, line, 0, err_str);
4764 			iput(inode);
4765 			return ERR_PTR(-EFSCORRUPTED);
4766 		}
4767 		return inode;
4768 	}
4769 
4770 	ei = EXT4_I(inode);
4771 	iloc.bh = NULL;
4772 
4773 	ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
4774 	if (ret < 0)
4775 		goto bad_inode;
4776 	raw_inode = ext4_raw_inode(&iloc);
4777 
4778 	if ((flags & EXT4_IGET_HANDLE) &&
4779 	    (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4780 		ret = -ESTALE;
4781 		goto bad_inode;
4782 	}
4783 
4784 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4785 		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4786 		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4787 			EXT4_INODE_SIZE(inode->i_sb) ||
4788 		    (ei->i_extra_isize & 3)) {
4789 			ext4_error_inode(inode, function, line, 0,
4790 					 "iget: bad extra_isize %u "
4791 					 "(inode size %u)",
4792 					 ei->i_extra_isize,
4793 					 EXT4_INODE_SIZE(inode->i_sb));
4794 			ret = -EFSCORRUPTED;
4795 			goto bad_inode;
4796 		}
4797 	} else
4798 		ei->i_extra_isize = 0;
4799 
4800 	/* Precompute checksum seed for inode metadata */
4801 	if (ext4_has_metadata_csum(sb)) {
4802 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4803 		__u32 csum;
4804 		__le32 inum = cpu_to_le32(inode->i_ino);
4805 		__le32 gen = raw_inode->i_generation;
4806 		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4807 				   sizeof(inum));
4808 		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4809 					      sizeof(gen));
4810 	}
4811 
4812 	if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4813 	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
4814 	     (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
4815 		ext4_error_inode_err(inode, function, line, 0,
4816 				EFSBADCRC, "iget: checksum invalid");
4817 		ret = -EFSBADCRC;
4818 		goto bad_inode;
4819 	}
4820 
4821 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4822 	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4823 	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4824 	if (ext4_has_feature_project(sb) &&
4825 	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4826 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4827 		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4828 	else
4829 		i_projid = EXT4_DEF_PROJID;
4830 
4831 	if (!(test_opt(inode->i_sb, NO_UID32))) {
4832 		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4833 		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4834 	}
4835 	i_uid_write(inode, i_uid);
4836 	i_gid_write(inode, i_gid);
4837 	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4838 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4839 
4840 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
4841 	ei->i_inline_off = 0;
4842 	ei->i_dir_start_lookup = 0;
4843 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4844 	/* We now have enough fields to check if the inode was active or not.
4845 	 * This is needed because nfsd might try to access dead inodes
4846 	 * the test is that same one that e2fsck uses
4847 	 * NeilBrown 1999oct15
4848 	 */
4849 	if (inode->i_nlink == 0) {
4850 		if ((inode->i_mode == 0 || flags & EXT4_IGET_SPECIAL ||
4851 		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4852 		    ino != EXT4_BOOT_LOADER_INO) {
4853 			/* this inode is deleted or unallocated */
4854 			if (flags & EXT4_IGET_SPECIAL) {
4855 				ext4_error_inode(inode, function, line, 0,
4856 						 "iget: special inode unallocated");
4857 				ret = -EFSCORRUPTED;
4858 			} else
4859 				ret = -ESTALE;
4860 			goto bad_inode;
4861 		}
4862 		/* The only unlinked inodes we let through here have
4863 		 * valid i_mode and are being read by the orphan
4864 		 * recovery code: that's fine, we're about to complete
4865 		 * the process of deleting those.
4866 		 * OR it is the EXT4_BOOT_LOADER_INO which is
4867 		 * not initialized on a new filesystem. */
4868 	}
4869 	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4870 	ext4_set_inode_flags(inode, true);
4871 	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4872 	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4873 	if (ext4_has_feature_64bit(sb))
4874 		ei->i_file_acl |=
4875 			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4876 	inode->i_size = ext4_isize(sb, raw_inode);
4877 	if ((size = i_size_read(inode)) < 0) {
4878 		ext4_error_inode(inode, function, line, 0,
4879 				 "iget: bad i_size value: %lld", size);
4880 		ret = -EFSCORRUPTED;
4881 		goto bad_inode;
4882 	}
4883 	/*
4884 	 * If dir_index is not enabled but there's dir with INDEX flag set,
4885 	 * we'd normally treat htree data as empty space. But with metadata
4886 	 * checksumming that corrupts checksums so forbid that.
4887 	 */
4888 	if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4889 	    ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4890 		ext4_error_inode(inode, function, line, 0,
4891 			 "iget: Dir with htree data on filesystem without dir_index feature.");
4892 		ret = -EFSCORRUPTED;
4893 		goto bad_inode;
4894 	}
4895 	ei->i_disksize = inode->i_size;
4896 #ifdef CONFIG_QUOTA
4897 	ei->i_reserved_quota = 0;
4898 #endif
4899 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4900 	ei->i_block_group = iloc.block_group;
4901 	ei->i_last_alloc_group = ~0;
4902 	/*
4903 	 * NOTE! The in-memory inode i_data array is in little-endian order
4904 	 * even on big-endian machines: we do NOT byteswap the block numbers!
4905 	 */
4906 	for (block = 0; block < EXT4_N_BLOCKS; block++)
4907 		ei->i_data[block] = raw_inode->i_block[block];
4908 	INIT_LIST_HEAD(&ei->i_orphan);
4909 	ext4_fc_init_inode(&ei->vfs_inode);
4910 
4911 	/*
4912 	 * Set transaction id's of transactions that have to be committed
4913 	 * to finish f[data]sync. We set them to currently running transaction
4914 	 * as we cannot be sure that the inode or some of its metadata isn't
4915 	 * part of the transaction - the inode could have been reclaimed and
4916 	 * now it is reread from disk.
4917 	 */
4918 	if (journal) {
4919 		transaction_t *transaction;
4920 		tid_t tid;
4921 
4922 		read_lock(&journal->j_state_lock);
4923 		if (journal->j_running_transaction)
4924 			transaction = journal->j_running_transaction;
4925 		else
4926 			transaction = journal->j_committing_transaction;
4927 		if (transaction)
4928 			tid = transaction->t_tid;
4929 		else
4930 			tid = journal->j_commit_sequence;
4931 		read_unlock(&journal->j_state_lock);
4932 		ei->i_sync_tid = tid;
4933 		ei->i_datasync_tid = tid;
4934 	}
4935 
4936 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4937 		if (ei->i_extra_isize == 0) {
4938 			/* The extra space is currently unused. Use it. */
4939 			BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4940 			ei->i_extra_isize = sizeof(struct ext4_inode) -
4941 					    EXT4_GOOD_OLD_INODE_SIZE;
4942 		} else {
4943 			ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4944 			if (ret)
4945 				goto bad_inode;
4946 		}
4947 	}
4948 
4949 	EXT4_INODE_GET_CTIME(inode, raw_inode);
4950 	EXT4_INODE_GET_ATIME(inode, raw_inode);
4951 	EXT4_INODE_GET_MTIME(inode, raw_inode);
4952 	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4953 
4954 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4955 		u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4956 
4957 		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4958 			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4959 				ivers |=
4960 		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4961 		}
4962 		ext4_inode_set_iversion_queried(inode, ivers);
4963 	}
4964 
4965 	ret = 0;
4966 	if (ei->i_file_acl &&
4967 	    !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4968 		ext4_error_inode(inode, function, line, 0,
4969 				 "iget: bad extended attribute block %llu",
4970 				 ei->i_file_acl);
4971 		ret = -EFSCORRUPTED;
4972 		goto bad_inode;
4973 	} else if (!ext4_has_inline_data(inode)) {
4974 		/* validate the block references in the inode */
4975 		if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4976 			(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4977 			(S_ISLNK(inode->i_mode) &&
4978 			!ext4_inode_is_fast_symlink(inode)))) {
4979 			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4980 				ret = ext4_ext_check_inode(inode);
4981 			else
4982 				ret = ext4_ind_check_inode(inode);
4983 		}
4984 	}
4985 	if (ret)
4986 		goto bad_inode;
4987 
4988 	if (S_ISREG(inode->i_mode)) {
4989 		inode->i_op = &ext4_file_inode_operations;
4990 		inode->i_fop = &ext4_file_operations;
4991 		ext4_set_aops(inode);
4992 	} else if (S_ISDIR(inode->i_mode)) {
4993 		inode->i_op = &ext4_dir_inode_operations;
4994 		inode->i_fop = &ext4_dir_operations;
4995 	} else if (S_ISLNK(inode->i_mode)) {
4996 		/* VFS does not allow setting these so must be corruption */
4997 		if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4998 			ext4_error_inode(inode, function, line, 0,
4999 					 "iget: immutable or append flags "
5000 					 "not allowed on symlinks");
5001 			ret = -EFSCORRUPTED;
5002 			goto bad_inode;
5003 		}
5004 		if (IS_ENCRYPTED(inode)) {
5005 			inode->i_op = &ext4_encrypted_symlink_inode_operations;
5006 		} else if (ext4_inode_is_fast_symlink(inode)) {
5007 			inode->i_link = (char *)ei->i_data;
5008 			inode->i_op = &ext4_fast_symlink_inode_operations;
5009 			nd_terminate_link(ei->i_data, inode->i_size,
5010 				sizeof(ei->i_data) - 1);
5011 		} else {
5012 			inode->i_op = &ext4_symlink_inode_operations;
5013 		}
5014 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
5015 	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
5016 		inode->i_op = &ext4_special_inode_operations;
5017 		if (raw_inode->i_block[0])
5018 			init_special_inode(inode, inode->i_mode,
5019 			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
5020 		else
5021 			init_special_inode(inode, inode->i_mode,
5022 			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
5023 	} else if (ino == EXT4_BOOT_LOADER_INO) {
5024 		make_bad_inode(inode);
5025 	} else {
5026 		ret = -EFSCORRUPTED;
5027 		ext4_error_inode(inode, function, line, 0,
5028 				 "iget: bogus i_mode (%o)", inode->i_mode);
5029 		goto bad_inode;
5030 	}
5031 	if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) {
5032 		ext4_error_inode(inode, function, line, 0,
5033 				 "casefold flag without casefold feature");
5034 		ret = -EFSCORRUPTED;
5035 		goto bad_inode;
5036 	}
5037 	if ((err_str = check_igot_inode(inode, flags)) != NULL) {
5038 		ext4_error_inode(inode, function, line, 0, err_str);
5039 		ret = -EFSCORRUPTED;
5040 		goto bad_inode;
5041 	}
5042 
5043 	brelse(iloc.bh);
5044 	unlock_new_inode(inode);
5045 	return inode;
5046 
5047 bad_inode:
5048 	brelse(iloc.bh);
5049 	iget_failed(inode);
5050 	return ERR_PTR(ret);
5051 }
5052 
__ext4_update_other_inode_time(struct super_block * sb,unsigned long orig_ino,unsigned long ino,struct ext4_inode * raw_inode)5053 static void __ext4_update_other_inode_time(struct super_block *sb,
5054 					   unsigned long orig_ino,
5055 					   unsigned long ino,
5056 					   struct ext4_inode *raw_inode)
5057 {
5058 	struct inode *inode;
5059 
5060 	inode = find_inode_by_ino_rcu(sb, ino);
5061 	if (!inode)
5062 		return;
5063 
5064 	if (!inode_is_dirtytime_only(inode))
5065 		return;
5066 
5067 	spin_lock(&inode->i_lock);
5068 	if (inode_is_dirtytime_only(inode)) {
5069 		struct ext4_inode_info	*ei = EXT4_I(inode);
5070 
5071 		inode->i_state &= ~I_DIRTY_TIME;
5072 		spin_unlock(&inode->i_lock);
5073 
5074 		spin_lock(&ei->i_raw_lock);
5075 		EXT4_INODE_SET_CTIME(inode, raw_inode);
5076 		EXT4_INODE_SET_MTIME(inode, raw_inode);
5077 		EXT4_INODE_SET_ATIME(inode, raw_inode);
5078 		ext4_inode_csum_set(inode, raw_inode, ei);
5079 		spin_unlock(&ei->i_raw_lock);
5080 		trace_ext4_other_inode_update_time(inode, orig_ino);
5081 		return;
5082 	}
5083 	spin_unlock(&inode->i_lock);
5084 }
5085 
5086 /*
5087  * Opportunistically update the other time fields for other inodes in
5088  * the same inode table block.
5089  */
ext4_update_other_inodes_time(struct super_block * sb,unsigned long orig_ino,char * buf)5090 static void ext4_update_other_inodes_time(struct super_block *sb,
5091 					  unsigned long orig_ino, char *buf)
5092 {
5093 	unsigned long ino;
5094 	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
5095 	int inode_size = EXT4_INODE_SIZE(sb);
5096 
5097 	/*
5098 	 * Calculate the first inode in the inode table block.  Inode
5099 	 * numbers are one-based.  That is, the first inode in a block
5100 	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
5101 	 */
5102 	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
5103 	rcu_read_lock();
5104 	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
5105 		if (ino == orig_ino)
5106 			continue;
5107 		__ext4_update_other_inode_time(sb, orig_ino, ino,
5108 					       (struct ext4_inode *)buf);
5109 	}
5110 	rcu_read_unlock();
5111 }
5112 
5113 /*
5114  * Post the struct inode info into an on-disk inode location in the
5115  * buffer-cache.  This gobbles the caller's reference to the
5116  * buffer_head in the inode location struct.
5117  *
5118  * The caller must have write access to iloc->bh.
5119  */
ext4_do_update_inode(handle_t * handle,struct inode * inode,struct ext4_iloc * iloc)5120 static int ext4_do_update_inode(handle_t *handle,
5121 				struct inode *inode,
5122 				struct ext4_iloc *iloc)
5123 {
5124 	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5125 	struct ext4_inode_info *ei = EXT4_I(inode);
5126 	struct buffer_head *bh = iloc->bh;
5127 	struct super_block *sb = inode->i_sb;
5128 	int err;
5129 	int need_datasync = 0, set_large_file = 0;
5130 
5131 	spin_lock(&ei->i_raw_lock);
5132 
5133 	/*
5134 	 * For fields not tracked in the in-memory inode, initialise them
5135 	 * to zero for new inodes.
5136 	 */
5137 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5138 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5139 
5140 	if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode))
5141 		need_datasync = 1;
5142 	if (ei->i_disksize > 0x7fffffffULL) {
5143 		if (!ext4_has_feature_large_file(sb) ||
5144 		    EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV))
5145 			set_large_file = 1;
5146 	}
5147 
5148 	err = ext4_fill_raw_inode(inode, raw_inode);
5149 	spin_unlock(&ei->i_raw_lock);
5150 	if (err) {
5151 		EXT4_ERROR_INODE(inode, "corrupted inode contents");
5152 		goto out_brelse;
5153 	}
5154 
5155 	if (inode->i_sb->s_flags & SB_LAZYTIME)
5156 		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5157 					      bh->b_data);
5158 
5159 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5160 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5161 	if (err)
5162 		goto out_error;
5163 	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5164 	if (set_large_file) {
5165 		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5166 		err = ext4_journal_get_write_access(handle, sb,
5167 						    EXT4_SB(sb)->s_sbh,
5168 						    EXT4_JTR_NONE);
5169 		if (err)
5170 			goto out_error;
5171 		lock_buffer(EXT4_SB(sb)->s_sbh);
5172 		ext4_set_feature_large_file(sb);
5173 		ext4_superblock_csum_set(sb);
5174 		unlock_buffer(EXT4_SB(sb)->s_sbh);
5175 		ext4_handle_sync(handle);
5176 		err = ext4_handle_dirty_metadata(handle, NULL,
5177 						 EXT4_SB(sb)->s_sbh);
5178 	}
5179 	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5180 out_error:
5181 	ext4_std_error(inode->i_sb, err);
5182 out_brelse:
5183 	brelse(bh);
5184 	return err;
5185 }
5186 
5187 /*
5188  * ext4_write_inode()
5189  *
5190  * We are called from a few places:
5191  *
5192  * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5193  *   Here, there will be no transaction running. We wait for any running
5194  *   transaction to commit.
5195  *
5196  * - Within flush work (sys_sync(), kupdate and such).
5197  *   We wait on commit, if told to.
5198  *
5199  * - Within iput_final() -> write_inode_now()
5200  *   We wait on commit, if told to.
5201  *
5202  * In all cases it is actually safe for us to return without doing anything,
5203  * because the inode has been copied into a raw inode buffer in
5204  * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5205  * writeback.
5206  *
5207  * Note that we are absolutely dependent upon all inode dirtiers doing the
5208  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5209  * which we are interested.
5210  *
5211  * It would be a bug for them to not do this.  The code:
5212  *
5213  *	mark_inode_dirty(inode)
5214  *	stuff();
5215  *	inode->i_size = expr;
5216  *
5217  * is in error because write_inode() could occur while `stuff()' is running,
5218  * and the new i_size will be lost.  Plus the inode will no longer be on the
5219  * superblock's dirty inode list.
5220  */
ext4_write_inode(struct inode * inode,struct writeback_control * wbc)5221 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5222 {
5223 	int err;
5224 
5225 	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
5226 		return 0;
5227 
5228 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
5229 		return -EIO;
5230 
5231 	if (EXT4_SB(inode->i_sb)->s_journal) {
5232 		if (ext4_journal_current_handle()) {
5233 			ext4_debug("called recursively, non-PF_MEMALLOC!\n");
5234 			dump_stack();
5235 			return -EIO;
5236 		}
5237 
5238 		/*
5239 		 * No need to force transaction in WB_SYNC_NONE mode. Also
5240 		 * ext4_sync_fs() will force the commit after everything is
5241 		 * written.
5242 		 */
5243 		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5244 			return 0;
5245 
5246 		err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
5247 						EXT4_I(inode)->i_sync_tid);
5248 	} else {
5249 		struct ext4_iloc iloc;
5250 
5251 		err = __ext4_get_inode_loc_noinmem(inode, &iloc);
5252 		if (err)
5253 			return err;
5254 		/*
5255 		 * sync(2) will flush the whole buffer cache. No need to do
5256 		 * it here separately for each inode.
5257 		 */
5258 		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5259 			sync_dirty_buffer(iloc.bh);
5260 		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5261 			ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5262 					       "IO error syncing inode");
5263 			err = -EIO;
5264 		}
5265 		brelse(iloc.bh);
5266 	}
5267 	return err;
5268 }
5269 
5270 /*
5271  * In data=journal mode ext4_journalled_invalidate_folio() may fail to invalidate
5272  * buffers that are attached to a folio straddling i_size and are undergoing
5273  * commit. In that case we have to wait for commit to finish and try again.
5274  */
ext4_wait_for_tail_page_commit(struct inode * inode)5275 static void ext4_wait_for_tail_page_commit(struct inode *inode)
5276 {
5277 	unsigned offset;
5278 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5279 	tid_t commit_tid = 0;
5280 	int ret;
5281 
5282 	offset = inode->i_size & (PAGE_SIZE - 1);
5283 	/*
5284 	 * If the folio is fully truncated, we don't need to wait for any commit
5285 	 * (and we even should not as __ext4_journalled_invalidate_folio() may
5286 	 * strip all buffers from the folio but keep the folio dirty which can then
5287 	 * confuse e.g. concurrent ext4_writepages() seeing dirty folio without
5288 	 * buffers). Also we don't need to wait for any commit if all buffers in
5289 	 * the folio remain valid. This is most beneficial for the common case of
5290 	 * blocksize == PAGESIZE.
5291 	 */
5292 	if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5293 		return;
5294 	while (1) {
5295 		struct folio *folio = filemap_lock_folio(inode->i_mapping,
5296 				      inode->i_size >> PAGE_SHIFT);
5297 		if (IS_ERR(folio))
5298 			return;
5299 		ret = __ext4_journalled_invalidate_folio(folio, offset,
5300 						folio_size(folio) - offset);
5301 		folio_unlock(folio);
5302 		folio_put(folio);
5303 		if (ret != -EBUSY)
5304 			return;
5305 		commit_tid = 0;
5306 		read_lock(&journal->j_state_lock);
5307 		if (journal->j_committing_transaction)
5308 			commit_tid = journal->j_committing_transaction->t_tid;
5309 		read_unlock(&journal->j_state_lock);
5310 		if (commit_tid)
5311 			jbd2_log_wait_commit(journal, commit_tid);
5312 	}
5313 }
5314 
5315 /*
5316  * ext4_setattr()
5317  *
5318  * Called from notify_change.
5319  *
5320  * We want to trap VFS attempts to truncate the file as soon as
5321  * possible.  In particular, we want to make sure that when the VFS
5322  * shrinks i_size, we put the inode on the orphan list and modify
5323  * i_disksize immediately, so that during the subsequent flushing of
5324  * dirty pages and freeing of disk blocks, we can guarantee that any
5325  * commit will leave the blocks being flushed in an unused state on
5326  * disk.  (On recovery, the inode will get truncated and the blocks will
5327  * be freed, so we have a strong guarantee that no future commit will
5328  * leave these blocks visible to the user.)
5329  *
5330  * Another thing we have to assure is that if we are in ordered mode
5331  * and inode is still attached to the committing transaction, we must
5332  * we start writeout of all the dirty pages which are being truncated.
5333  * This way we are sure that all the data written in the previous
5334  * transaction are already on disk (truncate waits for pages under
5335  * writeback).
5336  *
5337  * Called with inode->i_rwsem down.
5338  */
ext4_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)5339 int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
5340 		 struct iattr *attr)
5341 {
5342 	struct inode *inode = d_inode(dentry);
5343 	int error, rc = 0;
5344 	int orphan = 0;
5345 	const unsigned int ia_valid = attr->ia_valid;
5346 	bool inc_ivers = true;
5347 
5348 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
5349 		return -EIO;
5350 
5351 	if (unlikely(IS_IMMUTABLE(inode)))
5352 		return -EPERM;
5353 
5354 	if (unlikely(IS_APPEND(inode) &&
5355 		     (ia_valid & (ATTR_MODE | ATTR_UID |
5356 				  ATTR_GID | ATTR_TIMES_SET))))
5357 		return -EPERM;
5358 
5359 	error = setattr_prepare(idmap, dentry, attr);
5360 	if (error)
5361 		return error;
5362 
5363 	error = fscrypt_prepare_setattr(dentry, attr);
5364 	if (error)
5365 		return error;
5366 
5367 	error = fsverity_prepare_setattr(dentry, attr);
5368 	if (error)
5369 		return error;
5370 
5371 	if (is_quota_modification(idmap, inode, attr)) {
5372 		error = dquot_initialize(inode);
5373 		if (error)
5374 			return error;
5375 	}
5376 
5377 	if (i_uid_needs_update(idmap, attr, inode) ||
5378 	    i_gid_needs_update(idmap, attr, inode)) {
5379 		handle_t *handle;
5380 
5381 		/* (user+group)*(old+new) structure, inode write (sb,
5382 		 * inode block, ? - but truncate inode update has it) */
5383 		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5384 			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5385 			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5386 		if (IS_ERR(handle)) {
5387 			error = PTR_ERR(handle);
5388 			goto err_out;
5389 		}
5390 
5391 		/* dquot_transfer() calls back ext4_get_inode_usage() which
5392 		 * counts xattr inode references.
5393 		 */
5394 		down_read(&EXT4_I(inode)->xattr_sem);
5395 		error = dquot_transfer(idmap, inode, attr);
5396 		up_read(&EXT4_I(inode)->xattr_sem);
5397 
5398 		if (error) {
5399 			ext4_journal_stop(handle);
5400 			return error;
5401 		}
5402 		/* Update corresponding info in inode so that everything is in
5403 		 * one transaction */
5404 		i_uid_update(idmap, attr, inode);
5405 		i_gid_update(idmap, attr, inode);
5406 		error = ext4_mark_inode_dirty(handle, inode);
5407 		ext4_journal_stop(handle);
5408 		if (unlikely(error)) {
5409 			return error;
5410 		}
5411 	}
5412 
5413 	if (attr->ia_valid & ATTR_SIZE) {
5414 		handle_t *handle;
5415 		loff_t oldsize = inode->i_size;
5416 		loff_t old_disksize;
5417 		int shrink = (attr->ia_size < inode->i_size);
5418 
5419 		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5420 			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5421 
5422 			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5423 				return -EFBIG;
5424 			}
5425 		}
5426 		if (!S_ISREG(inode->i_mode)) {
5427 			return -EINVAL;
5428 		}
5429 
5430 		if (attr->ia_size == inode->i_size)
5431 			inc_ivers = false;
5432 
5433 		if (shrink) {
5434 			if (ext4_should_order_data(inode)) {
5435 				error = ext4_begin_ordered_truncate(inode,
5436 							    attr->ia_size);
5437 				if (error)
5438 					goto err_out;
5439 			}
5440 			/*
5441 			 * Blocks are going to be removed from the inode. Wait
5442 			 * for dio in flight.
5443 			 */
5444 			inode_dio_wait(inode);
5445 		}
5446 
5447 		filemap_invalidate_lock(inode->i_mapping);
5448 
5449 		rc = ext4_break_layouts(inode);
5450 		if (rc) {
5451 			filemap_invalidate_unlock(inode->i_mapping);
5452 			goto err_out;
5453 		}
5454 
5455 		if (attr->ia_size != inode->i_size) {
5456 			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5457 			if (IS_ERR(handle)) {
5458 				error = PTR_ERR(handle);
5459 				goto out_mmap_sem;
5460 			}
5461 			if (ext4_handle_valid(handle) && shrink) {
5462 				error = ext4_orphan_add(handle, inode);
5463 				orphan = 1;
5464 			}
5465 			/*
5466 			 * Update c/mtime on truncate up, ext4_truncate() will
5467 			 * update c/mtime in shrink case below
5468 			 */
5469 			if (!shrink)
5470 				inode_set_mtime_to_ts(inode,
5471 						      inode_set_ctime_current(inode));
5472 
5473 			if (shrink)
5474 				ext4_fc_track_range(handle, inode,
5475 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5476 					inode->i_sb->s_blocksize_bits,
5477 					EXT_MAX_BLOCKS - 1);
5478 			else
5479 				ext4_fc_track_range(
5480 					handle, inode,
5481 					(oldsize > 0 ? oldsize - 1 : oldsize) >>
5482 					inode->i_sb->s_blocksize_bits,
5483 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5484 					inode->i_sb->s_blocksize_bits);
5485 
5486 			down_write(&EXT4_I(inode)->i_data_sem);
5487 			old_disksize = EXT4_I(inode)->i_disksize;
5488 			EXT4_I(inode)->i_disksize = attr->ia_size;
5489 			rc = ext4_mark_inode_dirty(handle, inode);
5490 			if (!error)
5491 				error = rc;
5492 			/*
5493 			 * We have to update i_size under i_data_sem together
5494 			 * with i_disksize to avoid races with writeback code
5495 			 * running ext4_wb_update_i_disksize().
5496 			 */
5497 			if (!error)
5498 				i_size_write(inode, attr->ia_size);
5499 			else
5500 				EXT4_I(inode)->i_disksize = old_disksize;
5501 			up_write(&EXT4_I(inode)->i_data_sem);
5502 			ext4_journal_stop(handle);
5503 			if (error)
5504 				goto out_mmap_sem;
5505 			if (!shrink) {
5506 				pagecache_isize_extended(inode, oldsize,
5507 							 inode->i_size);
5508 			} else if (ext4_should_journal_data(inode)) {
5509 				ext4_wait_for_tail_page_commit(inode);
5510 			}
5511 		}
5512 
5513 		/*
5514 		 * Truncate pagecache after we've waited for commit
5515 		 * in data=journal mode to make pages freeable.
5516 		 */
5517 		truncate_pagecache(inode, inode->i_size);
5518 		/*
5519 		 * Call ext4_truncate() even if i_size didn't change to
5520 		 * truncate possible preallocated blocks.
5521 		 */
5522 		if (attr->ia_size <= oldsize) {
5523 			rc = ext4_truncate(inode);
5524 			if (rc)
5525 				error = rc;
5526 		}
5527 out_mmap_sem:
5528 		filemap_invalidate_unlock(inode->i_mapping);
5529 	}
5530 
5531 	if (!error) {
5532 		if (inc_ivers)
5533 			inode_inc_iversion(inode);
5534 		setattr_copy(idmap, inode, attr);
5535 		mark_inode_dirty(inode);
5536 	}
5537 
5538 	/*
5539 	 * If the call to ext4_truncate failed to get a transaction handle at
5540 	 * all, we need to clean up the in-core orphan list manually.
5541 	 */
5542 	if (orphan && inode->i_nlink)
5543 		ext4_orphan_del(NULL, inode);
5544 
5545 	if (!error && (ia_valid & ATTR_MODE))
5546 		rc = posix_acl_chmod(idmap, dentry, inode->i_mode);
5547 
5548 err_out:
5549 	if  (error)
5550 		ext4_std_error(inode->i_sb, error);
5551 	if (!error)
5552 		error = rc;
5553 	return error;
5554 }
5555 
ext4_dio_alignment(struct inode * inode)5556 u32 ext4_dio_alignment(struct inode *inode)
5557 {
5558 	if (fsverity_active(inode))
5559 		return 0;
5560 	if (ext4_should_journal_data(inode))
5561 		return 0;
5562 	if (ext4_has_inline_data(inode))
5563 		return 0;
5564 	if (IS_ENCRYPTED(inode)) {
5565 		if (!fscrypt_dio_supported(inode))
5566 			return 0;
5567 		return i_blocksize(inode);
5568 	}
5569 	return 1; /* use the iomap defaults */
5570 }
5571 
ext4_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)5572 int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
5573 		 struct kstat *stat, u32 request_mask, unsigned int query_flags)
5574 {
5575 	struct inode *inode = d_inode(path->dentry);
5576 	struct ext4_inode *raw_inode;
5577 	struct ext4_inode_info *ei = EXT4_I(inode);
5578 	unsigned int flags;
5579 
5580 	if ((request_mask & STATX_BTIME) &&
5581 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5582 		stat->result_mask |= STATX_BTIME;
5583 		stat->btime.tv_sec = ei->i_crtime.tv_sec;
5584 		stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5585 	}
5586 
5587 	/*
5588 	 * Return the DIO alignment restrictions if requested.  We only return
5589 	 * this information when requested, since on encrypted files it might
5590 	 * take a fair bit of work to get if the file wasn't opened recently.
5591 	 */
5592 	if ((request_mask & STATX_DIOALIGN) && S_ISREG(inode->i_mode)) {
5593 		u32 dio_align = ext4_dio_alignment(inode);
5594 
5595 		stat->result_mask |= STATX_DIOALIGN;
5596 		if (dio_align == 1) {
5597 			struct block_device *bdev = inode->i_sb->s_bdev;
5598 
5599 			/* iomap defaults */
5600 			stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
5601 			stat->dio_offset_align = bdev_logical_block_size(bdev);
5602 		} else {
5603 			stat->dio_mem_align = dio_align;
5604 			stat->dio_offset_align = dio_align;
5605 		}
5606 	}
5607 
5608 	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5609 	if (flags & EXT4_APPEND_FL)
5610 		stat->attributes |= STATX_ATTR_APPEND;
5611 	if (flags & EXT4_COMPR_FL)
5612 		stat->attributes |= STATX_ATTR_COMPRESSED;
5613 	if (flags & EXT4_ENCRYPT_FL)
5614 		stat->attributes |= STATX_ATTR_ENCRYPTED;
5615 	if (flags & EXT4_IMMUTABLE_FL)
5616 		stat->attributes |= STATX_ATTR_IMMUTABLE;
5617 	if (flags & EXT4_NODUMP_FL)
5618 		stat->attributes |= STATX_ATTR_NODUMP;
5619 	if (flags & EXT4_VERITY_FL)
5620 		stat->attributes |= STATX_ATTR_VERITY;
5621 
5622 	stat->attributes_mask |= (STATX_ATTR_APPEND |
5623 				  STATX_ATTR_COMPRESSED |
5624 				  STATX_ATTR_ENCRYPTED |
5625 				  STATX_ATTR_IMMUTABLE |
5626 				  STATX_ATTR_NODUMP |
5627 				  STATX_ATTR_VERITY);
5628 
5629 	generic_fillattr(idmap, request_mask, inode, stat);
5630 	return 0;
5631 }
5632 
ext4_file_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)5633 int ext4_file_getattr(struct mnt_idmap *idmap,
5634 		      const struct path *path, struct kstat *stat,
5635 		      u32 request_mask, unsigned int query_flags)
5636 {
5637 	struct inode *inode = d_inode(path->dentry);
5638 	u64 delalloc_blocks;
5639 
5640 	ext4_getattr(idmap, path, stat, request_mask, query_flags);
5641 
5642 	/*
5643 	 * If there is inline data in the inode, the inode will normally not
5644 	 * have data blocks allocated (it may have an external xattr block).
5645 	 * Report at least one sector for such files, so tools like tar, rsync,
5646 	 * others don't incorrectly think the file is completely sparse.
5647 	 */
5648 	if (unlikely(ext4_has_inline_data(inode)))
5649 		stat->blocks += (stat->size + 511) >> 9;
5650 
5651 	/*
5652 	 * We can't update i_blocks if the block allocation is delayed
5653 	 * otherwise in the case of system crash before the real block
5654 	 * allocation is done, we will have i_blocks inconsistent with
5655 	 * on-disk file blocks.
5656 	 * We always keep i_blocks updated together with real
5657 	 * allocation. But to not confuse with user, stat
5658 	 * will return the blocks that include the delayed allocation
5659 	 * blocks for this file.
5660 	 */
5661 	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5662 				   EXT4_I(inode)->i_reserved_data_blocks);
5663 	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5664 	return 0;
5665 }
5666 
ext4_index_trans_blocks(struct inode * inode,int lblocks,int pextents)5667 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5668 				   int pextents)
5669 {
5670 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5671 		return ext4_ind_trans_blocks(inode, lblocks);
5672 	return ext4_ext_index_trans_blocks(inode, pextents);
5673 }
5674 
5675 /*
5676  * Account for index blocks, block groups bitmaps and block group
5677  * descriptor blocks if modify datablocks and index blocks
5678  * worse case, the indexs blocks spread over different block groups
5679  *
5680  * If datablocks are discontiguous, they are possible to spread over
5681  * different block groups too. If they are contiguous, with flexbg,
5682  * they could still across block group boundary.
5683  *
5684  * Also account for superblock, inode, quota and xattr blocks
5685  */
ext4_meta_trans_blocks(struct inode * inode,int lblocks,int pextents)5686 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5687 				  int pextents)
5688 {
5689 	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5690 	int gdpblocks;
5691 	int idxblocks;
5692 	int ret;
5693 
5694 	/*
5695 	 * How many index blocks need to touch to map @lblocks logical blocks
5696 	 * to @pextents physical extents?
5697 	 */
5698 	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5699 
5700 	ret = idxblocks;
5701 
5702 	/*
5703 	 * Now let's see how many group bitmaps and group descriptors need
5704 	 * to account
5705 	 */
5706 	groups = idxblocks + pextents;
5707 	gdpblocks = groups;
5708 	if (groups > ngroups)
5709 		groups = ngroups;
5710 	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5711 		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5712 
5713 	/* bitmaps and block group descriptor blocks */
5714 	ret += groups + gdpblocks;
5715 
5716 	/* Blocks for super block, inode, quota and xattr blocks */
5717 	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5718 
5719 	return ret;
5720 }
5721 
5722 /*
5723  * Calculate the total number of credits to reserve to fit
5724  * the modification of a single pages into a single transaction,
5725  * which may include multiple chunks of block allocations.
5726  *
5727  * This could be called via ext4_write_begin()
5728  *
5729  * We need to consider the worse case, when
5730  * one new block per extent.
5731  */
ext4_writepage_trans_blocks(struct inode * inode)5732 int ext4_writepage_trans_blocks(struct inode *inode)
5733 {
5734 	int bpp = ext4_journal_blocks_per_page(inode);
5735 	int ret;
5736 
5737 	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5738 
5739 	/* Account for data blocks for journalled mode */
5740 	if (ext4_should_journal_data(inode))
5741 		ret += bpp;
5742 	return ret;
5743 }
5744 
5745 /*
5746  * Calculate the journal credits for a chunk of data modification.
5747  *
5748  * This is called from DIO, fallocate or whoever calling
5749  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5750  *
5751  * journal buffers for data blocks are not included here, as DIO
5752  * and fallocate do no need to journal data buffers.
5753  */
ext4_chunk_trans_blocks(struct inode * inode,int nrblocks)5754 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5755 {
5756 	return ext4_meta_trans_blocks(inode, nrblocks, 1);
5757 }
5758 
5759 /*
5760  * The caller must have previously called ext4_reserve_inode_write().
5761  * Give this, we know that the caller already has write access to iloc->bh.
5762  */
ext4_mark_iloc_dirty(handle_t * handle,struct inode * inode,struct ext4_iloc * iloc)5763 int ext4_mark_iloc_dirty(handle_t *handle,
5764 			 struct inode *inode, struct ext4_iloc *iloc)
5765 {
5766 	int err = 0;
5767 
5768 	if (unlikely(ext4_forced_shutdown(inode->i_sb))) {
5769 		put_bh(iloc->bh);
5770 		return -EIO;
5771 	}
5772 	ext4_fc_track_inode(handle, inode);
5773 
5774 	/* the do_update_inode consumes one bh->b_count */
5775 	get_bh(iloc->bh);
5776 
5777 	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5778 	err = ext4_do_update_inode(handle, inode, iloc);
5779 	put_bh(iloc->bh);
5780 	return err;
5781 }
5782 
5783 /*
5784  * On success, We end up with an outstanding reference count against
5785  * iloc->bh.  This _must_ be cleaned up later.
5786  */
5787 
5788 int
ext4_reserve_inode_write(handle_t * handle,struct inode * inode,struct ext4_iloc * iloc)5789 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5790 			 struct ext4_iloc *iloc)
5791 {
5792 	int err;
5793 
5794 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
5795 		return -EIO;
5796 
5797 	err = ext4_get_inode_loc(inode, iloc);
5798 	if (!err) {
5799 		BUFFER_TRACE(iloc->bh, "get_write_access");
5800 		err = ext4_journal_get_write_access(handle, inode->i_sb,
5801 						    iloc->bh, EXT4_JTR_NONE);
5802 		if (err) {
5803 			brelse(iloc->bh);
5804 			iloc->bh = NULL;
5805 		}
5806 	}
5807 	ext4_std_error(inode->i_sb, err);
5808 	return err;
5809 }
5810 
__ext4_expand_extra_isize(struct inode * inode,unsigned int new_extra_isize,struct ext4_iloc * iloc,handle_t * handle,int * no_expand)5811 static int __ext4_expand_extra_isize(struct inode *inode,
5812 				     unsigned int new_extra_isize,
5813 				     struct ext4_iloc *iloc,
5814 				     handle_t *handle, int *no_expand)
5815 {
5816 	struct ext4_inode *raw_inode;
5817 	struct ext4_xattr_ibody_header *header;
5818 	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5819 	struct ext4_inode_info *ei = EXT4_I(inode);
5820 	int error;
5821 
5822 	/* this was checked at iget time, but double check for good measure */
5823 	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5824 	    (ei->i_extra_isize & 3)) {
5825 		EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5826 				 ei->i_extra_isize,
5827 				 EXT4_INODE_SIZE(inode->i_sb));
5828 		return -EFSCORRUPTED;
5829 	}
5830 	if ((new_extra_isize < ei->i_extra_isize) ||
5831 	    (new_extra_isize < 4) ||
5832 	    (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5833 		return -EINVAL;	/* Should never happen */
5834 
5835 	raw_inode = ext4_raw_inode(iloc);
5836 
5837 	header = IHDR(inode, raw_inode);
5838 
5839 	/* No extended attributes present */
5840 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5841 	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5842 		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5843 		       EXT4_I(inode)->i_extra_isize, 0,
5844 		       new_extra_isize - EXT4_I(inode)->i_extra_isize);
5845 		EXT4_I(inode)->i_extra_isize = new_extra_isize;
5846 		return 0;
5847 	}
5848 
5849 	/*
5850 	 * We may need to allocate external xattr block so we need quotas
5851 	 * initialized. Here we can be called with various locks held so we
5852 	 * cannot affort to initialize quotas ourselves. So just bail.
5853 	 */
5854 	if (dquot_initialize_needed(inode))
5855 		return -EAGAIN;
5856 
5857 	/* try to expand with EAs present */
5858 	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5859 					   raw_inode, handle);
5860 	if (error) {
5861 		/*
5862 		 * Inode size expansion failed; don't try again
5863 		 */
5864 		*no_expand = 1;
5865 	}
5866 
5867 	return error;
5868 }
5869 
5870 /*
5871  * Expand an inode by new_extra_isize bytes.
5872  * Returns 0 on success or negative error number on failure.
5873  */
ext4_try_to_expand_extra_isize(struct inode * inode,unsigned int new_extra_isize,struct ext4_iloc iloc,handle_t * handle)5874 static int ext4_try_to_expand_extra_isize(struct inode *inode,
5875 					  unsigned int new_extra_isize,
5876 					  struct ext4_iloc iloc,
5877 					  handle_t *handle)
5878 {
5879 	int no_expand;
5880 	int error;
5881 
5882 	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5883 		return -EOVERFLOW;
5884 
5885 	/*
5886 	 * In nojournal mode, we can immediately attempt to expand
5887 	 * the inode.  When journaled, we first need to obtain extra
5888 	 * buffer credits since we may write into the EA block
5889 	 * with this same handle. If journal_extend fails, then it will
5890 	 * only result in a minor loss of functionality for that inode.
5891 	 * If this is felt to be critical, then e2fsck should be run to
5892 	 * force a large enough s_min_extra_isize.
5893 	 */
5894 	if (ext4_journal_extend(handle,
5895 				EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5896 		return -ENOSPC;
5897 
5898 	if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5899 		return -EBUSY;
5900 
5901 	error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5902 					  handle, &no_expand);
5903 	ext4_write_unlock_xattr(inode, &no_expand);
5904 
5905 	return error;
5906 }
5907 
ext4_expand_extra_isize(struct inode * inode,unsigned int new_extra_isize,struct ext4_iloc * iloc)5908 int ext4_expand_extra_isize(struct inode *inode,
5909 			    unsigned int new_extra_isize,
5910 			    struct ext4_iloc *iloc)
5911 {
5912 	handle_t *handle;
5913 	int no_expand;
5914 	int error, rc;
5915 
5916 	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5917 		brelse(iloc->bh);
5918 		return -EOVERFLOW;
5919 	}
5920 
5921 	handle = ext4_journal_start(inode, EXT4_HT_INODE,
5922 				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5923 	if (IS_ERR(handle)) {
5924 		error = PTR_ERR(handle);
5925 		brelse(iloc->bh);
5926 		return error;
5927 	}
5928 
5929 	ext4_write_lock_xattr(inode, &no_expand);
5930 
5931 	BUFFER_TRACE(iloc->bh, "get_write_access");
5932 	error = ext4_journal_get_write_access(handle, inode->i_sb, iloc->bh,
5933 					      EXT4_JTR_NONE);
5934 	if (error) {
5935 		brelse(iloc->bh);
5936 		goto out_unlock;
5937 	}
5938 
5939 	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5940 					  handle, &no_expand);
5941 
5942 	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5943 	if (!error)
5944 		error = rc;
5945 
5946 out_unlock:
5947 	ext4_write_unlock_xattr(inode, &no_expand);
5948 	ext4_journal_stop(handle);
5949 	return error;
5950 }
5951 
5952 /*
5953  * What we do here is to mark the in-core inode as clean with respect to inode
5954  * dirtiness (it may still be data-dirty).
5955  * This means that the in-core inode may be reaped by prune_icache
5956  * without having to perform any I/O.  This is a very good thing,
5957  * because *any* task may call prune_icache - even ones which
5958  * have a transaction open against a different journal.
5959  *
5960  * Is this cheating?  Not really.  Sure, we haven't written the
5961  * inode out, but prune_icache isn't a user-visible syncing function.
5962  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5963  * we start and wait on commits.
5964  */
__ext4_mark_inode_dirty(handle_t * handle,struct inode * inode,const char * func,unsigned int line)5965 int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5966 				const char *func, unsigned int line)
5967 {
5968 	struct ext4_iloc iloc;
5969 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5970 	int err;
5971 
5972 	might_sleep();
5973 	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5974 	err = ext4_reserve_inode_write(handle, inode, &iloc);
5975 	if (err)
5976 		goto out;
5977 
5978 	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5979 		ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5980 					       iloc, handle);
5981 
5982 	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5983 out:
5984 	if (unlikely(err))
5985 		ext4_error_inode_err(inode, func, line, 0, err,
5986 					"mark_inode_dirty error");
5987 	return err;
5988 }
5989 
5990 /*
5991  * ext4_dirty_inode() is called from __mark_inode_dirty()
5992  *
5993  * We're really interested in the case where a file is being extended.
5994  * i_size has been changed by generic_commit_write() and we thus need
5995  * to include the updated inode in the current transaction.
5996  *
5997  * Also, dquot_alloc_block() will always dirty the inode when blocks
5998  * are allocated to the file.
5999  *
6000  * If the inode is marked synchronous, we don't honour that here - doing
6001  * so would cause a commit on atime updates, which we don't bother doing.
6002  * We handle synchronous inodes at the highest possible level.
6003  */
ext4_dirty_inode(struct inode * inode,int flags)6004 void ext4_dirty_inode(struct inode *inode, int flags)
6005 {
6006 	handle_t *handle;
6007 
6008 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
6009 	if (IS_ERR(handle))
6010 		return;
6011 	ext4_mark_inode_dirty(handle, inode);
6012 	ext4_journal_stop(handle);
6013 }
6014 
ext4_change_inode_journal_flag(struct inode * inode,int val)6015 int ext4_change_inode_journal_flag(struct inode *inode, int val)
6016 {
6017 	journal_t *journal;
6018 	handle_t *handle;
6019 	int err;
6020 	int alloc_ctx;
6021 
6022 	/*
6023 	 * We have to be very careful here: changing a data block's
6024 	 * journaling status dynamically is dangerous.  If we write a
6025 	 * data block to the journal, change the status and then delete
6026 	 * that block, we risk forgetting to revoke the old log record
6027 	 * from the journal and so a subsequent replay can corrupt data.
6028 	 * So, first we make sure that the journal is empty and that
6029 	 * nobody is changing anything.
6030 	 */
6031 
6032 	journal = EXT4_JOURNAL(inode);
6033 	if (!journal)
6034 		return 0;
6035 	if (is_journal_aborted(journal))
6036 		return -EROFS;
6037 
6038 	/* Wait for all existing dio workers */
6039 	inode_dio_wait(inode);
6040 
6041 	/*
6042 	 * Before flushing the journal and switching inode's aops, we have
6043 	 * to flush all dirty data the inode has. There can be outstanding
6044 	 * delayed allocations, there can be unwritten extents created by
6045 	 * fallocate or buffered writes in dioread_nolock mode covered by
6046 	 * dirty data which can be converted only after flushing the dirty
6047 	 * data (and journalled aops don't know how to handle these cases).
6048 	 */
6049 	if (val) {
6050 		filemap_invalidate_lock(inode->i_mapping);
6051 		err = filemap_write_and_wait(inode->i_mapping);
6052 		if (err < 0) {
6053 			filemap_invalidate_unlock(inode->i_mapping);
6054 			return err;
6055 		}
6056 	}
6057 
6058 	alloc_ctx = ext4_writepages_down_write(inode->i_sb);
6059 	jbd2_journal_lock_updates(journal);
6060 
6061 	/*
6062 	 * OK, there are no updates running now, and all cached data is
6063 	 * synced to disk.  We are now in a completely consistent state
6064 	 * which doesn't have anything in the journal, and we know that
6065 	 * no filesystem updates are running, so it is safe to modify
6066 	 * the inode's in-core data-journaling state flag now.
6067 	 */
6068 
6069 	if (val)
6070 		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6071 	else {
6072 		err = jbd2_journal_flush(journal, 0);
6073 		if (err < 0) {
6074 			jbd2_journal_unlock_updates(journal);
6075 			ext4_writepages_up_write(inode->i_sb, alloc_ctx);
6076 			return err;
6077 		}
6078 		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6079 	}
6080 	ext4_set_aops(inode);
6081 
6082 	jbd2_journal_unlock_updates(journal);
6083 	ext4_writepages_up_write(inode->i_sb, alloc_ctx);
6084 
6085 	if (val)
6086 		filemap_invalidate_unlock(inode->i_mapping);
6087 
6088 	/* Finally we can mark the inode as dirty. */
6089 
6090 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
6091 	if (IS_ERR(handle))
6092 		return PTR_ERR(handle);
6093 
6094 	ext4_fc_mark_ineligible(inode->i_sb,
6095 		EXT4_FC_REASON_JOURNAL_FLAG_CHANGE, handle);
6096 	err = ext4_mark_inode_dirty(handle, inode);
6097 	ext4_handle_sync(handle);
6098 	ext4_journal_stop(handle);
6099 	ext4_std_error(inode->i_sb, err);
6100 
6101 	return err;
6102 }
6103 
ext4_bh_unmapped(handle_t * handle,struct inode * inode,struct buffer_head * bh)6104 static int ext4_bh_unmapped(handle_t *handle, struct inode *inode,
6105 			    struct buffer_head *bh)
6106 {
6107 	return !buffer_mapped(bh);
6108 }
6109 
ext4_page_mkwrite(struct vm_fault * vmf)6110 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6111 {
6112 	struct vm_area_struct *vma = vmf->vma;
6113 	struct folio *folio = page_folio(vmf->page);
6114 	loff_t size;
6115 	unsigned long len;
6116 	int err;
6117 	vm_fault_t ret;
6118 	struct file *file = vma->vm_file;
6119 	struct inode *inode = file_inode(file);
6120 	struct address_space *mapping = inode->i_mapping;
6121 	handle_t *handle;
6122 	get_block_t *get_block;
6123 	int retries = 0;
6124 
6125 	if (unlikely(IS_IMMUTABLE(inode)))
6126 		return VM_FAULT_SIGBUS;
6127 
6128 	sb_start_pagefault(inode->i_sb);
6129 	file_update_time(vma->vm_file);
6130 
6131 	filemap_invalidate_lock_shared(mapping);
6132 
6133 	err = ext4_convert_inline_data(inode);
6134 	if (err)
6135 		goto out_ret;
6136 
6137 	/*
6138 	 * On data journalling we skip straight to the transaction handle:
6139 	 * there's no delalloc; page truncated will be checked later; the
6140 	 * early return w/ all buffers mapped (calculates size/len) can't
6141 	 * be used; and there's no dioread_nolock, so only ext4_get_block.
6142 	 */
6143 	if (ext4_should_journal_data(inode))
6144 		goto retry_alloc;
6145 
6146 	/* Delalloc case is easy... */
6147 	if (test_opt(inode->i_sb, DELALLOC) &&
6148 	    !ext4_nonda_switch(inode->i_sb)) {
6149 		do {
6150 			err = block_page_mkwrite(vma, vmf,
6151 						   ext4_da_get_block_prep);
6152 		} while (err == -ENOSPC &&
6153 		       ext4_should_retry_alloc(inode->i_sb, &retries));
6154 		goto out_ret;
6155 	}
6156 
6157 	folio_lock(folio);
6158 	size = i_size_read(inode);
6159 	/* Page got truncated from under us? */
6160 	if (folio->mapping != mapping || folio_pos(folio) > size) {
6161 		folio_unlock(folio);
6162 		ret = VM_FAULT_NOPAGE;
6163 		goto out;
6164 	}
6165 
6166 	len = folio_size(folio);
6167 	if (folio_pos(folio) + len > size)
6168 		len = size - folio_pos(folio);
6169 	/*
6170 	 * Return if we have all the buffers mapped. This avoids the need to do
6171 	 * journal_start/journal_stop which can block and take a long time
6172 	 *
6173 	 * This cannot be done for data journalling, as we have to add the
6174 	 * inode to the transaction's list to writeprotect pages on commit.
6175 	 */
6176 	if (folio_buffers(folio)) {
6177 		if (!ext4_walk_page_buffers(NULL, inode, folio_buffers(folio),
6178 					    0, len, NULL,
6179 					    ext4_bh_unmapped)) {
6180 			/* Wait so that we don't change page under IO */
6181 			folio_wait_stable(folio);
6182 			ret = VM_FAULT_LOCKED;
6183 			goto out;
6184 		}
6185 	}
6186 	folio_unlock(folio);
6187 	/* OK, we need to fill the hole... */
6188 	if (ext4_should_dioread_nolock(inode))
6189 		get_block = ext4_get_block_unwritten;
6190 	else
6191 		get_block = ext4_get_block;
6192 retry_alloc:
6193 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6194 				    ext4_writepage_trans_blocks(inode));
6195 	if (IS_ERR(handle)) {
6196 		ret = VM_FAULT_SIGBUS;
6197 		goto out;
6198 	}
6199 	/*
6200 	 * Data journalling can't use block_page_mkwrite() because it
6201 	 * will set_buffer_dirty() before do_journal_get_write_access()
6202 	 * thus might hit warning messages for dirty metadata buffers.
6203 	 */
6204 	if (!ext4_should_journal_data(inode)) {
6205 		err = block_page_mkwrite(vma, vmf, get_block);
6206 	} else {
6207 		folio_lock(folio);
6208 		size = i_size_read(inode);
6209 		/* Page got truncated from under us? */
6210 		if (folio->mapping != mapping || folio_pos(folio) > size) {
6211 			ret = VM_FAULT_NOPAGE;
6212 			goto out_error;
6213 		}
6214 
6215 		len = folio_size(folio);
6216 		if (folio_pos(folio) + len > size)
6217 			len = size - folio_pos(folio);
6218 
6219 		err = __block_write_begin(folio, 0, len, ext4_get_block);
6220 		if (!err) {
6221 			ret = VM_FAULT_SIGBUS;
6222 			if (ext4_journal_folio_buffers(handle, folio, len))
6223 				goto out_error;
6224 		} else {
6225 			folio_unlock(folio);
6226 		}
6227 	}
6228 	ext4_journal_stop(handle);
6229 	if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6230 		goto retry_alloc;
6231 out_ret:
6232 	ret = vmf_fs_error(err);
6233 out:
6234 	filemap_invalidate_unlock_shared(mapping);
6235 	sb_end_pagefault(inode->i_sb);
6236 	return ret;
6237 out_error:
6238 	folio_unlock(folio);
6239 	ext4_journal_stop(handle);
6240 	goto out;
6241 }
6242