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, 0);
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 
456 /*
457  * The ext4_map_blocks() function tries to look up the requested blocks,
458  * and returns if the blocks are already mapped.
459  *
460  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
461  * and store the allocated blocks in the result buffer head and mark it
462  * mapped.
463  *
464  * If file type is extents based, it will call ext4_ext_map_blocks(),
465  * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
466  * based files
467  *
468  * On success, it returns the number of blocks being mapped or allocated.  if
469  * create==0 and the blocks are pre-allocated and unwritten, the resulting @map
470  * is marked as unwritten. If the create == 1, it will mark @map as mapped.
471  *
472  * It returns 0 if plain look up failed (blocks have not been allocated), in
473  * that case, @map is returned as unmapped but we still do fill map->m_len to
474  * indicate the length of a hole starting at map->m_lblk.
475  *
476  * It returns the error in case of allocation failure.
477  */
ext4_map_blocks(handle_t * handle,struct inode * inode,struct ext4_map_blocks * map,int flags)478 int ext4_map_blocks(handle_t *handle, struct inode *inode,
479 		    struct ext4_map_blocks *map, int flags)
480 {
481 	struct extent_status es;
482 	int retval;
483 	int ret = 0;
484 #ifdef ES_AGGRESSIVE_TEST
485 	struct ext4_map_blocks orig_map;
486 
487 	memcpy(&orig_map, map, sizeof(*map));
488 #endif
489 
490 	map->m_flags = 0;
491 	ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
492 		  flags, map->m_len, (unsigned long) map->m_lblk);
493 
494 	/*
495 	 * ext4_map_blocks returns an int, and m_len is an unsigned int
496 	 */
497 	if (unlikely(map->m_len > INT_MAX))
498 		map->m_len = INT_MAX;
499 
500 	/* We can handle the block number less than EXT_MAX_BLOCKS */
501 	if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
502 		return -EFSCORRUPTED;
503 
504 	/* Lookup extent status tree firstly */
505 	if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
506 	    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
507 		if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
508 			map->m_pblk = ext4_es_pblock(&es) +
509 					map->m_lblk - es.es_lblk;
510 			map->m_flags |= ext4_es_is_written(&es) ?
511 					EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
512 			retval = es.es_len - (map->m_lblk - es.es_lblk);
513 			if (retval > map->m_len)
514 				retval = map->m_len;
515 			map->m_len = retval;
516 		} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
517 			map->m_pblk = 0;
518 			retval = es.es_len - (map->m_lblk - es.es_lblk);
519 			if (retval > map->m_len)
520 				retval = map->m_len;
521 			map->m_len = retval;
522 			retval = 0;
523 		} else {
524 			BUG();
525 		}
526 
527 		if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
528 			return retval;
529 #ifdef ES_AGGRESSIVE_TEST
530 		ext4_map_blocks_es_recheck(handle, inode, map,
531 					   &orig_map, flags);
532 #endif
533 		goto found;
534 	}
535 	/*
536 	 * In the query cache no-wait mode, nothing we can do more if we
537 	 * cannot find extent in the cache.
538 	 */
539 	if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
540 		return 0;
541 
542 	/*
543 	 * Try to see if we can get the block without requesting a new
544 	 * file system block.
545 	 */
546 	down_read(&EXT4_I(inode)->i_data_sem);
547 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
548 		retval = ext4_ext_map_blocks(handle, inode, map, 0);
549 	} else {
550 		retval = ext4_ind_map_blocks(handle, inode, map, 0);
551 	}
552 	if (retval > 0) {
553 		unsigned int status;
554 
555 		if (unlikely(retval != map->m_len)) {
556 			ext4_warning(inode->i_sb,
557 				     "ES len assertion failed for inode "
558 				     "%lu: retval %d != map->m_len %d",
559 				     inode->i_ino, retval, map->m_len);
560 			WARN_ON(1);
561 		}
562 
563 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
564 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
565 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
566 		    !(status & EXTENT_STATUS_WRITTEN) &&
567 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
568 				       map->m_lblk + map->m_len - 1))
569 			status |= EXTENT_STATUS_DELAYED;
570 		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
571 				      map->m_pblk, status);
572 	}
573 	up_read((&EXT4_I(inode)->i_data_sem));
574 
575 found:
576 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
577 		ret = check_block_validity(inode, map);
578 		if (ret != 0)
579 			return ret;
580 	}
581 
582 	/* If it is only a block(s) look up */
583 	if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
584 		return retval;
585 
586 	/*
587 	 * Returns if the blocks have already allocated
588 	 *
589 	 * Note that if blocks have been preallocated
590 	 * ext4_ext_get_block() returns the create = 0
591 	 * with buffer head unmapped.
592 	 */
593 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
594 		/*
595 		 * If we need to convert extent to unwritten
596 		 * we continue and do the actual work in
597 		 * ext4_ext_map_blocks()
598 		 */
599 		if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
600 			return retval;
601 
602 	/*
603 	 * Here we clear m_flags because after allocating an new extent,
604 	 * it will be set again.
605 	 */
606 	map->m_flags &= ~EXT4_MAP_FLAGS;
607 
608 	/*
609 	 * New blocks allocate and/or writing to unwritten extent
610 	 * will possibly result in updating i_data, so we take
611 	 * the write lock of i_data_sem, and call get_block()
612 	 * with create == 1 flag.
613 	 */
614 	down_write(&EXT4_I(inode)->i_data_sem);
615 
616 	/*
617 	 * We need to check for EXT4 here because migrate
618 	 * could have changed the inode type in between
619 	 */
620 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
621 		retval = ext4_ext_map_blocks(handle, inode, map, flags);
622 	} else {
623 		retval = ext4_ind_map_blocks(handle, inode, map, flags);
624 
625 		if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
626 			/*
627 			 * We allocated new blocks which will result in
628 			 * i_data's format changing.  Force the migrate
629 			 * to fail by clearing migrate flags
630 			 */
631 			ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
632 		}
633 	}
634 
635 	if (retval > 0) {
636 		unsigned int status;
637 
638 		if (unlikely(retval != map->m_len)) {
639 			ext4_warning(inode->i_sb,
640 				     "ES len assertion failed for inode "
641 				     "%lu: retval %d != map->m_len %d",
642 				     inode->i_ino, retval, map->m_len);
643 			WARN_ON(1);
644 		}
645 
646 		/*
647 		 * We have to zeroout blocks before inserting them into extent
648 		 * status tree. Otherwise someone could look them up there and
649 		 * use them before they are really zeroed. We also have to
650 		 * unmap metadata before zeroing as otherwise writeback can
651 		 * overwrite zeros with stale data from block device.
652 		 */
653 		if (flags & EXT4_GET_BLOCKS_ZERO &&
654 		    map->m_flags & EXT4_MAP_MAPPED &&
655 		    map->m_flags & EXT4_MAP_NEW) {
656 			ret = ext4_issue_zeroout(inode, map->m_lblk,
657 						 map->m_pblk, map->m_len);
658 			if (ret) {
659 				retval = ret;
660 				goto out_sem;
661 			}
662 		}
663 
664 		/*
665 		 * If the extent has been zeroed out, we don't need to update
666 		 * extent status tree.
667 		 */
668 		if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
669 		    ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
670 			if (ext4_es_is_written(&es))
671 				goto out_sem;
672 		}
673 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
674 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
675 		if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
676 		    !(status & EXTENT_STATUS_WRITTEN) &&
677 		    ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
678 				       map->m_lblk + map->m_len - 1))
679 			status |= EXTENT_STATUS_DELAYED;
680 		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
681 				      map->m_pblk, status);
682 	}
683 
684 out_sem:
685 	up_write((&EXT4_I(inode)->i_data_sem));
686 	if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
687 		ret = check_block_validity(inode, map);
688 		if (ret != 0)
689 			return ret;
690 
691 		/*
692 		 * Inodes with freshly allocated blocks where contents will be
693 		 * visible after transaction commit must be on transaction's
694 		 * ordered data list.
695 		 */
696 		if (map->m_flags & EXT4_MAP_NEW &&
697 		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
698 		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
699 		    !ext4_is_quota_file(inode) &&
700 		    ext4_should_order_data(inode)) {
701 			loff_t start_byte =
702 				(loff_t)map->m_lblk << inode->i_blkbits;
703 			loff_t length = (loff_t)map->m_len << inode->i_blkbits;
704 
705 			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
706 				ret = ext4_jbd2_inode_add_wait(handle, inode,
707 						start_byte, length);
708 			else
709 				ret = ext4_jbd2_inode_add_write(handle, inode,
710 						start_byte, length);
711 			if (ret)
712 				return ret;
713 		}
714 	}
715 	if (retval > 0 && (map->m_flags & EXT4_MAP_UNWRITTEN ||
716 				map->m_flags & EXT4_MAP_MAPPED))
717 		ext4_fc_track_range(handle, inode, map->m_lblk,
718 					map->m_lblk + map->m_len - 1);
719 	if (retval < 0)
720 		ext_debug(inode, "failed with err %d\n", retval);
721 	return retval;
722 }
723 
724 /*
725  * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
726  * we have to be careful as someone else may be manipulating b_state as well.
727  */
ext4_update_bh_state(struct buffer_head * bh,unsigned long flags)728 static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
729 {
730 	unsigned long old_state;
731 	unsigned long new_state;
732 
733 	flags &= EXT4_MAP_FLAGS;
734 
735 	/* Dummy buffer_head? Set non-atomically. */
736 	if (!bh->b_page) {
737 		bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
738 		return;
739 	}
740 	/*
741 	 * Someone else may be modifying b_state. Be careful! This is ugly but
742 	 * once we get rid of using bh as a container for mapping information
743 	 * to pass to / from get_block functions, this can go away.
744 	 */
745 	old_state = READ_ONCE(bh->b_state);
746 	do {
747 		new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
748 	} while (unlikely(!try_cmpxchg(&bh->b_state, &old_state, new_state)));
749 }
750 
_ext4_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int flags)751 static int _ext4_get_block(struct inode *inode, sector_t iblock,
752 			   struct buffer_head *bh, int flags)
753 {
754 	struct ext4_map_blocks map;
755 	int ret = 0;
756 
757 	if (ext4_has_inline_data(inode))
758 		return -ERANGE;
759 
760 	map.m_lblk = iblock;
761 	map.m_len = bh->b_size >> inode->i_blkbits;
762 
763 	ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
764 			      flags);
765 	if (ret > 0) {
766 		map_bh(bh, inode->i_sb, map.m_pblk);
767 		ext4_update_bh_state(bh, map.m_flags);
768 		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
769 		ret = 0;
770 	} else if (ret == 0) {
771 		/* hole case, need to fill in bh->b_size */
772 		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
773 	}
774 	return ret;
775 }
776 
ext4_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)777 int ext4_get_block(struct inode *inode, sector_t iblock,
778 		   struct buffer_head *bh, int create)
779 {
780 	return _ext4_get_block(inode, iblock, bh,
781 			       create ? EXT4_GET_BLOCKS_CREATE : 0);
782 }
783 
784 /*
785  * Get block function used when preparing for buffered write if we require
786  * creating an unwritten extent if blocks haven't been allocated.  The extent
787  * will be converted to written after the IO is complete.
788  */
ext4_get_block_unwritten(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)789 int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
790 			     struct buffer_head *bh_result, int create)
791 {
792 	int ret = 0;
793 
794 	ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
795 		   inode->i_ino, create);
796 	ret = _ext4_get_block(inode, iblock, bh_result,
797 			       EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
798 
799 	/*
800 	 * If the buffer is marked unwritten, mark it as new to make sure it is
801 	 * zeroed out correctly in case of partial writes. Otherwise, there is
802 	 * a chance of stale data getting exposed.
803 	 */
804 	if (ret == 0 && buffer_unwritten(bh_result))
805 		set_buffer_new(bh_result);
806 
807 	return ret;
808 }
809 
810 /* Maximum number of blocks we map for direct IO at once. */
811 #define DIO_MAX_BLOCKS 4096
812 
813 /*
814  * `handle' can be NULL if create is zero
815  */
ext4_getblk(handle_t * handle,struct inode * inode,ext4_lblk_t block,int map_flags)816 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
817 				ext4_lblk_t block, int map_flags)
818 {
819 	struct ext4_map_blocks map;
820 	struct buffer_head *bh;
821 	int create = map_flags & EXT4_GET_BLOCKS_CREATE;
822 	bool nowait = map_flags & EXT4_GET_BLOCKS_CACHED_NOWAIT;
823 	int err;
824 
825 	ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
826 		    || handle != NULL || create == 0);
827 	ASSERT(create == 0 || !nowait);
828 
829 	map.m_lblk = block;
830 	map.m_len = 1;
831 	err = ext4_map_blocks(handle, inode, &map, map_flags);
832 
833 	if (err == 0)
834 		return create ? ERR_PTR(-ENOSPC) : NULL;
835 	if (err < 0)
836 		return ERR_PTR(err);
837 
838 	if (nowait)
839 		return sb_find_get_block(inode->i_sb, map.m_pblk);
840 
841 	bh = sb_getblk(inode->i_sb, map.m_pblk);
842 	if (unlikely(!bh))
843 		return ERR_PTR(-ENOMEM);
844 	if (map.m_flags & EXT4_MAP_NEW) {
845 		ASSERT(create != 0);
846 		ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
847 			    || (handle != NULL));
848 
849 		/*
850 		 * Now that we do not always journal data, we should
851 		 * keep in mind whether this should always journal the
852 		 * new buffer as metadata.  For now, regular file
853 		 * writes use ext4_get_block instead, so it's not a
854 		 * problem.
855 		 */
856 		lock_buffer(bh);
857 		BUFFER_TRACE(bh, "call get_create_access");
858 		err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
859 						     EXT4_JTR_NONE);
860 		if (unlikely(err)) {
861 			unlock_buffer(bh);
862 			goto errout;
863 		}
864 		if (!buffer_uptodate(bh)) {
865 			memset(bh->b_data, 0, inode->i_sb->s_blocksize);
866 			set_buffer_uptodate(bh);
867 		}
868 		unlock_buffer(bh);
869 		BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
870 		err = ext4_handle_dirty_metadata(handle, inode, bh);
871 		if (unlikely(err))
872 			goto errout;
873 	} else
874 		BUFFER_TRACE(bh, "not a new buffer");
875 	return bh;
876 errout:
877 	brelse(bh);
878 	return ERR_PTR(err);
879 }
880 
ext4_bread(handle_t * handle,struct inode * inode,ext4_lblk_t block,int map_flags)881 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
882 			       ext4_lblk_t block, int map_flags)
883 {
884 	struct buffer_head *bh;
885 	int ret;
886 
887 	bh = ext4_getblk(handle, inode, block, map_flags);
888 	if (IS_ERR(bh))
889 		return bh;
890 	if (!bh || ext4_buffer_uptodate(bh))
891 		return bh;
892 
893 	ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
894 	if (ret) {
895 		put_bh(bh);
896 		return ERR_PTR(ret);
897 	}
898 	return bh;
899 }
900 
901 /* 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)902 int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
903 		     bool wait, struct buffer_head **bhs)
904 {
905 	int i, err;
906 
907 	for (i = 0; i < bh_count; i++) {
908 		bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
909 		if (IS_ERR(bhs[i])) {
910 			err = PTR_ERR(bhs[i]);
911 			bh_count = i;
912 			goto out_brelse;
913 		}
914 	}
915 
916 	for (i = 0; i < bh_count; i++)
917 		/* Note that NULL bhs[i] is valid because of holes. */
918 		if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
919 			ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
920 
921 	if (!wait)
922 		return 0;
923 
924 	for (i = 0; i < bh_count; i++)
925 		if (bhs[i])
926 			wait_on_buffer(bhs[i]);
927 
928 	for (i = 0; i < bh_count; i++) {
929 		if (bhs[i] && !buffer_uptodate(bhs[i])) {
930 			err = -EIO;
931 			goto out_brelse;
932 		}
933 	}
934 	return 0;
935 
936 out_brelse:
937 	for (i = 0; i < bh_count; i++) {
938 		brelse(bhs[i]);
939 		bhs[i] = NULL;
940 	}
941 	return err;
942 }
943 
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))944 int ext4_walk_page_buffers(handle_t *handle, struct inode *inode,
945 			   struct buffer_head *head,
946 			   unsigned from,
947 			   unsigned to,
948 			   int *partial,
949 			   int (*fn)(handle_t *handle, struct inode *inode,
950 				     struct buffer_head *bh))
951 {
952 	struct buffer_head *bh;
953 	unsigned block_start, block_end;
954 	unsigned blocksize = head->b_size;
955 	int err, ret = 0;
956 	struct buffer_head *next;
957 
958 	for (bh = head, block_start = 0;
959 	     ret == 0 && (bh != head || !block_start);
960 	     block_start = block_end, bh = next) {
961 		next = bh->b_this_page;
962 		block_end = block_start + blocksize;
963 		if (block_end <= from || block_start >= to) {
964 			if (partial && !buffer_uptodate(bh))
965 				*partial = 1;
966 			continue;
967 		}
968 		err = (*fn)(handle, inode, bh);
969 		if (!ret)
970 			ret = err;
971 	}
972 	return ret;
973 }
974 
975 /*
976  * Helper for handling dirtying of journalled data. We also mark the folio as
977  * dirty so that writeback code knows about this page (and inode) contains
978  * dirty data. ext4_writepages() then commits appropriate transaction to
979  * make data stable.
980  */
ext4_dirty_journalled_data(handle_t * handle,struct buffer_head * bh)981 static int ext4_dirty_journalled_data(handle_t *handle, struct buffer_head *bh)
982 {
983 	folio_mark_dirty(bh->b_folio);
984 	return ext4_handle_dirty_metadata(handle, NULL, bh);
985 }
986 
do_journal_get_write_access(handle_t * handle,struct inode * inode,struct buffer_head * bh)987 int do_journal_get_write_access(handle_t *handle, struct inode *inode,
988 				struct buffer_head *bh)
989 {
990 	int dirty = buffer_dirty(bh);
991 	int ret;
992 
993 	if (!buffer_mapped(bh) || buffer_freed(bh))
994 		return 0;
995 	/*
996 	 * __block_write_begin() could have dirtied some buffers. Clean
997 	 * the dirty bit as jbd2_journal_get_write_access() could complain
998 	 * otherwise about fs integrity issues. Setting of the dirty bit
999 	 * by __block_write_begin() isn't a real problem here as we clear
1000 	 * the bit before releasing a page lock and thus writeback cannot
1001 	 * ever write the buffer.
1002 	 */
1003 	if (dirty)
1004 		clear_buffer_dirty(bh);
1005 	BUFFER_TRACE(bh, "get write access");
1006 	ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
1007 					    EXT4_JTR_NONE);
1008 	if (!ret && dirty)
1009 		ret = ext4_dirty_journalled_data(handle, bh);
1010 	return ret;
1011 }
1012 
1013 #ifdef CONFIG_FS_ENCRYPTION
ext4_block_write_begin(struct folio * folio,loff_t pos,unsigned len,get_block_t * get_block)1014 static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
1015 				  get_block_t *get_block)
1016 {
1017 	unsigned from = pos & (PAGE_SIZE - 1);
1018 	unsigned to = from + len;
1019 	struct inode *inode = folio->mapping->host;
1020 	unsigned block_start, block_end;
1021 	sector_t block;
1022 	int err = 0;
1023 	unsigned blocksize = inode->i_sb->s_blocksize;
1024 	unsigned bbits;
1025 	struct buffer_head *bh, *head, *wait[2];
1026 	int nr_wait = 0;
1027 	int i;
1028 
1029 	BUG_ON(!folio_test_locked(folio));
1030 	BUG_ON(from > PAGE_SIZE);
1031 	BUG_ON(to > PAGE_SIZE);
1032 	BUG_ON(from > to);
1033 
1034 	head = folio_buffers(folio);
1035 	if (!head) {
1036 		create_empty_buffers(&folio->page, blocksize, 0);
1037 		head = folio_buffers(folio);
1038 	}
1039 	bbits = ilog2(blocksize);
1040 	block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
1041 
1042 	for (bh = head, block_start = 0; bh != head || !block_start;
1043 	    block++, block_start = block_end, bh = bh->b_this_page) {
1044 		block_end = block_start + blocksize;
1045 		if (block_end <= from || block_start >= to) {
1046 			if (folio_test_uptodate(folio)) {
1047 				set_buffer_uptodate(bh);
1048 			}
1049 			continue;
1050 		}
1051 		if (buffer_new(bh))
1052 			clear_buffer_new(bh);
1053 		if (!buffer_mapped(bh)) {
1054 			WARN_ON(bh->b_size != blocksize);
1055 			err = get_block(inode, block, bh, 1);
1056 			if (err)
1057 				break;
1058 			if (buffer_new(bh)) {
1059 				if (folio_test_uptodate(folio)) {
1060 					clear_buffer_new(bh);
1061 					set_buffer_uptodate(bh);
1062 					mark_buffer_dirty(bh);
1063 					continue;
1064 				}
1065 				if (block_end > to || block_start < from)
1066 					folio_zero_segments(folio, to,
1067 							    block_end,
1068 							    block_start, from);
1069 				continue;
1070 			}
1071 		}
1072 		if (folio_test_uptodate(folio)) {
1073 			set_buffer_uptodate(bh);
1074 			continue;
1075 		}
1076 		if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
1077 		    !buffer_unwritten(bh) &&
1078 		    (block_start < from || block_end > to)) {
1079 			ext4_read_bh_lock(bh, 0, false);
1080 			wait[nr_wait++] = bh;
1081 		}
1082 	}
1083 	/*
1084 	 * If we issued read requests, let them complete.
1085 	 */
1086 	for (i = 0; i < nr_wait; i++) {
1087 		wait_on_buffer(wait[i]);
1088 		if (!buffer_uptodate(wait[i]))
1089 			err = -EIO;
1090 	}
1091 	if (unlikely(err)) {
1092 		folio_zero_new_buffers(folio, from, to);
1093 	} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
1094 		for (i = 0; i < nr_wait; i++) {
1095 			int err2;
1096 
1097 			err2 = fscrypt_decrypt_pagecache_blocks(folio,
1098 						blocksize, bh_offset(wait[i]));
1099 			if (err2) {
1100 				clear_buffer_uptodate(wait[i]);
1101 				err = err2;
1102 			}
1103 		}
1104 	}
1105 
1106 	return err;
1107 }
1108 #endif
1109 
1110 /*
1111  * To preserve ordering, it is essential that the hole instantiation and
1112  * the data write be encapsulated in a single transaction.  We cannot
1113  * close off a transaction and start a new one between the ext4_get_block()
1114  * and the ext4_write_end().  So doing the jbd2_journal_start at the start of
1115  * ext4_write_begin() is the right place.
1116  */
ext4_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)1117 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1118 			    loff_t pos, unsigned len,
1119 			    struct page **pagep, void **fsdata)
1120 {
1121 	struct inode *inode = mapping->host;
1122 	int ret, needed_blocks;
1123 	handle_t *handle;
1124 	int retries = 0;
1125 	struct folio *folio;
1126 	pgoff_t index;
1127 	unsigned from, to;
1128 
1129 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
1130 		return -EIO;
1131 
1132 	trace_ext4_write_begin(inode, pos, len);
1133 	/*
1134 	 * Reserve one block more for addition to orphan list in case
1135 	 * we allocate blocks but write fails for some reason
1136 	 */
1137 	needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1138 	index = pos >> PAGE_SHIFT;
1139 	from = pos & (PAGE_SIZE - 1);
1140 	to = from + len;
1141 
1142 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
1143 		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
1144 						    pagep);
1145 		if (ret < 0)
1146 			return ret;
1147 		if (ret == 1)
1148 			return 0;
1149 	}
1150 
1151 	/*
1152 	 * __filemap_get_folio() can take a long time if the
1153 	 * system is thrashing due to memory pressure, or if the folio
1154 	 * is being written back.  So grab it first before we start
1155 	 * the transaction handle.  This also allows us to allocate
1156 	 * the folio (if needed) without using GFP_NOFS.
1157 	 */
1158 retry_grab:
1159 	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
1160 					mapping_gfp_mask(mapping));
1161 	if (IS_ERR(folio))
1162 		return PTR_ERR(folio);
1163 	/*
1164 	 * The same as page allocation, we prealloc buffer heads before
1165 	 * starting the handle.
1166 	 */
1167 	if (!folio_buffers(folio))
1168 		create_empty_buffers(&folio->page, inode->i_sb->s_blocksize, 0);
1169 
1170 	folio_unlock(folio);
1171 
1172 retry_journal:
1173 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
1174 	if (IS_ERR(handle)) {
1175 		folio_put(folio);
1176 		return PTR_ERR(handle);
1177 	}
1178 
1179 	folio_lock(folio);
1180 	if (folio->mapping != mapping) {
1181 		/* The folio got truncated from under us */
1182 		folio_unlock(folio);
1183 		folio_put(folio);
1184 		ext4_journal_stop(handle);
1185 		goto retry_grab;
1186 	}
1187 	/* In case writeback began while the folio was unlocked */
1188 	folio_wait_stable(folio);
1189 
1190 #ifdef CONFIG_FS_ENCRYPTION
1191 	if (ext4_should_dioread_nolock(inode))
1192 		ret = ext4_block_write_begin(folio, pos, len,
1193 					     ext4_get_block_unwritten);
1194 	else
1195 		ret = ext4_block_write_begin(folio, pos, len, ext4_get_block);
1196 #else
1197 	if (ext4_should_dioread_nolock(inode))
1198 		ret = __block_write_begin(&folio->page, pos, len,
1199 					  ext4_get_block_unwritten);
1200 	else
1201 		ret = __block_write_begin(&folio->page, pos, len, ext4_get_block);
1202 #endif
1203 	if (!ret && ext4_should_journal_data(inode)) {
1204 		ret = ext4_walk_page_buffers(handle, inode,
1205 					     folio_buffers(folio), from, to,
1206 					     NULL, do_journal_get_write_access);
1207 	}
1208 
1209 	if (ret) {
1210 		bool extended = (pos + len > inode->i_size) &&
1211 				!ext4_verity_in_progress(inode);
1212 
1213 		folio_unlock(folio);
1214 		/*
1215 		 * __block_write_begin may have instantiated a few blocks
1216 		 * outside i_size.  Trim these off again. Don't need
1217 		 * i_size_read because we hold i_rwsem.
1218 		 *
1219 		 * Add inode to orphan list in case we crash before
1220 		 * truncate finishes
1221 		 */
1222 		if (extended && ext4_can_truncate(inode))
1223 			ext4_orphan_add(handle, inode);
1224 
1225 		ext4_journal_stop(handle);
1226 		if (extended) {
1227 			ext4_truncate_failed_write(inode);
1228 			/*
1229 			 * If truncate failed early the inode might
1230 			 * still be on the orphan list; we need to
1231 			 * make sure the inode is removed from the
1232 			 * orphan list in that case.
1233 			 */
1234 			if (inode->i_nlink)
1235 				ext4_orphan_del(NULL, inode);
1236 		}
1237 
1238 		if (ret == -ENOSPC &&
1239 		    ext4_should_retry_alloc(inode->i_sb, &retries))
1240 			goto retry_journal;
1241 		folio_put(folio);
1242 		return ret;
1243 	}
1244 	*pagep = &folio->page;
1245 	return ret;
1246 }
1247 
1248 /* For write_end() in data=journal mode */
write_end_fn(handle_t * handle,struct inode * inode,struct buffer_head * bh)1249 static int write_end_fn(handle_t *handle, struct inode *inode,
1250 			struct buffer_head *bh)
1251 {
1252 	int ret;
1253 	if (!buffer_mapped(bh) || buffer_freed(bh))
1254 		return 0;
1255 	set_buffer_uptodate(bh);
1256 	ret = ext4_dirty_journalled_data(handle, bh);
1257 	clear_buffer_meta(bh);
1258 	clear_buffer_prio(bh);
1259 	return ret;
1260 }
1261 
1262 /*
1263  * We need to pick up the new inode size which generic_commit_write gave us
1264  * `file' can be NULL - eg, when called from page_symlink().
1265  *
1266  * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1267  * buffers are managed internally.
1268  */
ext4_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)1269 static int ext4_write_end(struct file *file,
1270 			  struct address_space *mapping,
1271 			  loff_t pos, unsigned len, unsigned copied,
1272 			  struct page *page, void *fsdata)
1273 {
1274 	struct folio *folio = page_folio(page);
1275 	handle_t *handle = ext4_journal_current_handle();
1276 	struct inode *inode = mapping->host;
1277 	loff_t old_size = inode->i_size;
1278 	int ret = 0, ret2;
1279 	int i_size_changed = 0;
1280 	bool verity = ext4_verity_in_progress(inode);
1281 
1282 	trace_ext4_write_end(inode, pos, len, copied);
1283 
1284 	if (ext4_has_inline_data(inode) &&
1285 	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
1286 		return ext4_write_inline_data_end(inode, pos, len, copied,
1287 						  folio);
1288 
1289 	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1290 	/*
1291 	 * it's important to update i_size while still holding folio lock:
1292 	 * page writeout could otherwise come in and zero beyond i_size.
1293 	 *
1294 	 * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
1295 	 * blocks are being written past EOF, so skip the i_size update.
1296 	 */
1297 	if (!verity)
1298 		i_size_changed = ext4_update_inode_size(inode, pos + copied);
1299 	folio_unlock(folio);
1300 	folio_put(folio);
1301 
1302 	if (old_size < pos && !verity)
1303 		pagecache_isize_extended(inode, old_size, pos);
1304 	/*
1305 	 * Don't mark the inode dirty under folio lock. First, it unnecessarily
1306 	 * makes the holding time of folio lock longer. Second, it forces lock
1307 	 * ordering of folio lock and transaction start for journaling
1308 	 * filesystems.
1309 	 */
1310 	if (i_size_changed)
1311 		ret = ext4_mark_inode_dirty(handle, inode);
1312 
1313 	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1314 		/* if we have allocated more blocks and copied
1315 		 * less. We will have blocks allocated outside
1316 		 * inode->i_size. So truncate them
1317 		 */
1318 		ext4_orphan_add(handle, inode);
1319 
1320 	ret2 = ext4_journal_stop(handle);
1321 	if (!ret)
1322 		ret = ret2;
1323 
1324 	if (pos + len > inode->i_size && !verity) {
1325 		ext4_truncate_failed_write(inode);
1326 		/*
1327 		 * If truncate failed early the inode might still be
1328 		 * on the orphan list; we need to make sure the inode
1329 		 * is removed from the orphan list in that case.
1330 		 */
1331 		if (inode->i_nlink)
1332 			ext4_orphan_del(NULL, inode);
1333 	}
1334 
1335 	return ret ? ret : copied;
1336 }
1337 
1338 /*
1339  * This is a private version of folio_zero_new_buffers() which doesn't
1340  * set the buffer to be dirty, since in data=journalled mode we need
1341  * to call ext4_dirty_journalled_data() instead.
1342  */
ext4_journalled_zero_new_buffers(handle_t * handle,struct inode * inode,struct folio * folio,unsigned from,unsigned to)1343 static void ext4_journalled_zero_new_buffers(handle_t *handle,
1344 					    struct inode *inode,
1345 					    struct folio *folio,
1346 					    unsigned from, unsigned to)
1347 {
1348 	unsigned int block_start = 0, block_end;
1349 	struct buffer_head *head, *bh;
1350 
1351 	bh = head = folio_buffers(folio);
1352 	do {
1353 		block_end = block_start + bh->b_size;
1354 		if (buffer_new(bh)) {
1355 			if (block_end > from && block_start < to) {
1356 				if (!folio_test_uptodate(folio)) {
1357 					unsigned start, size;
1358 
1359 					start = max(from, block_start);
1360 					size = min(to, block_end) - start;
1361 
1362 					folio_zero_range(folio, start, size);
1363 					write_end_fn(handle, inode, bh);
1364 				}
1365 				clear_buffer_new(bh);
1366 			}
1367 		}
1368 		block_start = block_end;
1369 		bh = bh->b_this_page;
1370 	} while (bh != head);
1371 }
1372 
ext4_journalled_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)1373 static int ext4_journalled_write_end(struct file *file,
1374 				     struct address_space *mapping,
1375 				     loff_t pos, unsigned len, unsigned copied,
1376 				     struct page *page, void *fsdata)
1377 {
1378 	struct folio *folio = page_folio(page);
1379 	handle_t *handle = ext4_journal_current_handle();
1380 	struct inode *inode = mapping->host;
1381 	loff_t old_size = inode->i_size;
1382 	int ret = 0, ret2;
1383 	int partial = 0;
1384 	unsigned from, to;
1385 	int size_changed = 0;
1386 	bool verity = ext4_verity_in_progress(inode);
1387 
1388 	trace_ext4_journalled_write_end(inode, pos, len, copied);
1389 	from = pos & (PAGE_SIZE - 1);
1390 	to = from + len;
1391 
1392 	BUG_ON(!ext4_handle_valid(handle));
1393 
1394 	if (ext4_has_inline_data(inode))
1395 		return ext4_write_inline_data_end(inode, pos, len, copied,
1396 						  folio);
1397 
1398 	if (unlikely(copied < len) && !folio_test_uptodate(folio)) {
1399 		copied = 0;
1400 		ext4_journalled_zero_new_buffers(handle, inode, folio,
1401 						 from, to);
1402 	} else {
1403 		if (unlikely(copied < len))
1404 			ext4_journalled_zero_new_buffers(handle, inode, folio,
1405 							 from + copied, to);
1406 		ret = ext4_walk_page_buffers(handle, inode,
1407 					     folio_buffers(folio),
1408 					     from, from + copied, &partial,
1409 					     write_end_fn);
1410 		if (!partial)
1411 			folio_mark_uptodate(folio);
1412 	}
1413 	if (!verity)
1414 		size_changed = ext4_update_inode_size(inode, pos + copied);
1415 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
1416 	folio_unlock(folio);
1417 	folio_put(folio);
1418 
1419 	if (old_size < pos && !verity)
1420 		pagecache_isize_extended(inode, old_size, pos);
1421 
1422 	if (size_changed) {
1423 		ret2 = ext4_mark_inode_dirty(handle, inode);
1424 		if (!ret)
1425 			ret = ret2;
1426 	}
1427 
1428 	if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
1429 		/* if we have allocated more blocks and copied
1430 		 * less. We will have blocks allocated outside
1431 		 * inode->i_size. So truncate them
1432 		 */
1433 		ext4_orphan_add(handle, inode);
1434 
1435 	ret2 = ext4_journal_stop(handle);
1436 	if (!ret)
1437 		ret = ret2;
1438 	if (pos + len > inode->i_size && !verity) {
1439 		ext4_truncate_failed_write(inode);
1440 		/*
1441 		 * If truncate failed early the inode might still be
1442 		 * on the orphan list; we need to make sure the inode
1443 		 * is removed from the orphan list in that case.
1444 		 */
1445 		if (inode->i_nlink)
1446 			ext4_orphan_del(NULL, inode);
1447 	}
1448 
1449 	return ret ? ret : copied;
1450 }
1451 
1452 /*
1453  * Reserve space for a single cluster
1454  */
ext4_da_reserve_space(struct inode * inode)1455 static int ext4_da_reserve_space(struct inode *inode)
1456 {
1457 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1458 	struct ext4_inode_info *ei = EXT4_I(inode);
1459 	int ret;
1460 
1461 	/*
1462 	 * We will charge metadata quota at writeout time; this saves
1463 	 * us from metadata over-estimation, though we may go over by
1464 	 * a small amount in the end.  Here we just reserve for data.
1465 	 */
1466 	ret = dquot_reserve_block(inode, EXT4_C2B(sbi, 1));
1467 	if (ret)
1468 		return ret;
1469 
1470 	spin_lock(&ei->i_block_reservation_lock);
1471 	if (ext4_claim_free_clusters(sbi, 1, 0)) {
1472 		spin_unlock(&ei->i_block_reservation_lock);
1473 		dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1));
1474 		return -ENOSPC;
1475 	}
1476 	ei->i_reserved_data_blocks++;
1477 	trace_ext4_da_reserve_space(inode);
1478 	spin_unlock(&ei->i_block_reservation_lock);
1479 
1480 	return 0;       /* success */
1481 }
1482 
ext4_da_release_space(struct inode * inode,int to_free)1483 void ext4_da_release_space(struct inode *inode, int to_free)
1484 {
1485 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1486 	struct ext4_inode_info *ei = EXT4_I(inode);
1487 
1488 	if (!to_free)
1489 		return;		/* Nothing to release, exit */
1490 
1491 	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1492 
1493 	trace_ext4_da_release_space(inode, to_free);
1494 	if (unlikely(to_free > ei->i_reserved_data_blocks)) {
1495 		/*
1496 		 * if there aren't enough reserved blocks, then the
1497 		 * counter is messed up somewhere.  Since this
1498 		 * function is called from invalidate page, it's
1499 		 * harmless to return without any action.
1500 		 */
1501 		ext4_warning(inode->i_sb, "ext4_da_release_space: "
1502 			 "ino %lu, to_free %d with only %d reserved "
1503 			 "data blocks", inode->i_ino, to_free,
1504 			 ei->i_reserved_data_blocks);
1505 		WARN_ON(1);
1506 		to_free = ei->i_reserved_data_blocks;
1507 	}
1508 	ei->i_reserved_data_blocks -= to_free;
1509 
1510 	/* update fs dirty data blocks counter */
1511 	percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
1512 
1513 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1514 
1515 	dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
1516 }
1517 
1518 /*
1519  * Delayed allocation stuff
1520  */
1521 
1522 struct mpage_da_data {
1523 	/* These are input fields for ext4_do_writepages() */
1524 	struct inode *inode;
1525 	struct writeback_control *wbc;
1526 	unsigned int can_map:1;	/* Can writepages call map blocks? */
1527 
1528 	/* These are internal state of ext4_do_writepages() */
1529 	pgoff_t first_page;	/* The first page to write */
1530 	pgoff_t next_page;	/* Current page to examine */
1531 	pgoff_t last_page;	/* Last page to examine */
1532 	/*
1533 	 * Extent to map - this can be after first_page because that can be
1534 	 * fully mapped. We somewhat abuse m_flags to store whether the extent
1535 	 * is delalloc or unwritten.
1536 	 */
1537 	struct ext4_map_blocks map;
1538 	struct ext4_io_submit io_submit;	/* IO submission data */
1539 	unsigned int do_map:1;
1540 	unsigned int scanned_until_end:1;
1541 	unsigned int journalled_more_data:1;
1542 };
1543 
mpage_release_unused_pages(struct mpage_da_data * mpd,bool invalidate)1544 static void mpage_release_unused_pages(struct mpage_da_data *mpd,
1545 				       bool invalidate)
1546 {
1547 	unsigned nr, i;
1548 	pgoff_t index, end;
1549 	struct folio_batch fbatch;
1550 	struct inode *inode = mpd->inode;
1551 	struct address_space *mapping = inode->i_mapping;
1552 
1553 	/* This is necessary when next_page == 0. */
1554 	if (mpd->first_page >= mpd->next_page)
1555 		return;
1556 
1557 	mpd->scanned_until_end = 0;
1558 	index = mpd->first_page;
1559 	end   = mpd->next_page - 1;
1560 	if (invalidate) {
1561 		ext4_lblk_t start, last;
1562 		start = index << (PAGE_SHIFT - inode->i_blkbits);
1563 		last = end << (PAGE_SHIFT - inode->i_blkbits);
1564 
1565 		/*
1566 		 * avoid racing with extent status tree scans made by
1567 		 * ext4_insert_delayed_block()
1568 		 */
1569 		down_write(&EXT4_I(inode)->i_data_sem);
1570 		ext4_es_remove_extent(inode, start, last - start + 1);
1571 		up_write(&EXT4_I(inode)->i_data_sem);
1572 	}
1573 
1574 	folio_batch_init(&fbatch);
1575 	while (index <= end) {
1576 		nr = filemap_get_folios(mapping, &index, end, &fbatch);
1577 		if (nr == 0)
1578 			break;
1579 		for (i = 0; i < nr; i++) {
1580 			struct folio *folio = fbatch.folios[i];
1581 
1582 			if (folio->index < mpd->first_page)
1583 				continue;
1584 			if (folio_next_index(folio) - 1 > end)
1585 				continue;
1586 			BUG_ON(!folio_test_locked(folio));
1587 			BUG_ON(folio_test_writeback(folio));
1588 			if (invalidate) {
1589 				if (folio_mapped(folio))
1590 					folio_clear_dirty_for_io(folio);
1591 				block_invalidate_folio(folio, 0,
1592 						folio_size(folio));
1593 				folio_clear_uptodate(folio);
1594 			}
1595 			folio_unlock(folio);
1596 		}
1597 		folio_batch_release(&fbatch);
1598 	}
1599 }
1600 
ext4_print_free_blocks(struct inode * inode)1601 static void ext4_print_free_blocks(struct inode *inode)
1602 {
1603 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1604 	struct super_block *sb = inode->i_sb;
1605 	struct ext4_inode_info *ei = EXT4_I(inode);
1606 
1607 	ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
1608 	       EXT4_C2B(EXT4_SB(inode->i_sb),
1609 			ext4_count_free_clusters(sb)));
1610 	ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
1611 	ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
1612 	       (long long) EXT4_C2B(EXT4_SB(sb),
1613 		percpu_counter_sum(&sbi->s_freeclusters_counter)));
1614 	ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
1615 	       (long long) EXT4_C2B(EXT4_SB(sb),
1616 		percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
1617 	ext4_msg(sb, KERN_CRIT, "Block reservation details");
1618 	ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
1619 		 ei->i_reserved_data_blocks);
1620 	return;
1621 }
1622 
1623 /*
1624  * ext4_insert_delayed_block - adds a delayed block to the extents status
1625  *                             tree, incrementing the reserved cluster/block
1626  *                             count or making a pending reservation
1627  *                             where needed
1628  *
1629  * @inode - file containing the newly added block
1630  * @lblk - logical block to be added
1631  *
1632  * Returns 0 on success, negative error code on failure.
1633  */
ext4_insert_delayed_block(struct inode * inode,ext4_lblk_t lblk)1634 static int ext4_insert_delayed_block(struct inode *inode, ext4_lblk_t lblk)
1635 {
1636 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1637 	int ret;
1638 	bool allocated = false;
1639 
1640 	/*
1641 	 * If the cluster containing lblk is shared with a delayed,
1642 	 * written, or unwritten extent in a bigalloc file system, it's
1643 	 * already been accounted for and does not need to be reserved.
1644 	 * A pending reservation must be made for the cluster if it's
1645 	 * shared with a written or unwritten extent and doesn't already
1646 	 * have one.  Written and unwritten extents can be purged from the
1647 	 * extents status tree if the system is under memory pressure, so
1648 	 * it's necessary to examine the extent tree if a search of the
1649 	 * extents status tree doesn't get a match.
1650 	 */
1651 	if (sbi->s_cluster_ratio == 1) {
1652 		ret = ext4_da_reserve_space(inode);
1653 		if (ret != 0)   /* ENOSPC */
1654 			return ret;
1655 	} else {   /* bigalloc */
1656 		if (!ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk)) {
1657 			if (!ext4_es_scan_clu(inode,
1658 					      &ext4_es_is_mapped, lblk)) {
1659 				ret = ext4_clu_mapped(inode,
1660 						      EXT4_B2C(sbi, lblk));
1661 				if (ret < 0)
1662 					return ret;
1663 				if (ret == 0) {
1664 					ret = ext4_da_reserve_space(inode);
1665 					if (ret != 0)   /* ENOSPC */
1666 						return ret;
1667 				} else {
1668 					allocated = true;
1669 				}
1670 			} else {
1671 				allocated = true;
1672 			}
1673 		}
1674 	}
1675 
1676 	ext4_es_insert_delayed_block(inode, lblk, allocated);
1677 	return 0;
1678 }
1679 
1680 /*
1681  * This function is grabs code from the very beginning of
1682  * ext4_map_blocks, but assumes that the caller is from delayed write
1683  * time. This function looks up the requested blocks and sets the
1684  * buffer delay bit under the protection of i_data_sem.
1685  */
ext4_da_map_blocks(struct inode * inode,sector_t iblock,struct ext4_map_blocks * map,struct buffer_head * bh)1686 static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
1687 			      struct ext4_map_blocks *map,
1688 			      struct buffer_head *bh)
1689 {
1690 	struct extent_status es;
1691 	int retval;
1692 	sector_t invalid_block = ~((sector_t) 0xffff);
1693 #ifdef ES_AGGRESSIVE_TEST
1694 	struct ext4_map_blocks orig_map;
1695 
1696 	memcpy(&orig_map, map, sizeof(*map));
1697 #endif
1698 
1699 	if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
1700 		invalid_block = ~0;
1701 
1702 	map->m_flags = 0;
1703 	ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
1704 		  (unsigned long) map->m_lblk);
1705 
1706 	/* Lookup extent status tree firstly */
1707 	if (ext4_es_lookup_extent(inode, iblock, NULL, &es)) {
1708 		if (ext4_es_is_hole(&es)) {
1709 			retval = 0;
1710 			down_read(&EXT4_I(inode)->i_data_sem);
1711 			goto add_delayed;
1712 		}
1713 
1714 		/*
1715 		 * Delayed extent could be allocated by fallocate.
1716 		 * So we need to check it.
1717 		 */
1718 		if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) {
1719 			map_bh(bh, inode->i_sb, invalid_block);
1720 			set_buffer_new(bh);
1721 			set_buffer_delay(bh);
1722 			return 0;
1723 		}
1724 
1725 		map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk;
1726 		retval = es.es_len - (iblock - es.es_lblk);
1727 		if (retval > map->m_len)
1728 			retval = map->m_len;
1729 		map->m_len = retval;
1730 		if (ext4_es_is_written(&es))
1731 			map->m_flags |= EXT4_MAP_MAPPED;
1732 		else if (ext4_es_is_unwritten(&es))
1733 			map->m_flags |= EXT4_MAP_UNWRITTEN;
1734 		else
1735 			BUG();
1736 
1737 #ifdef ES_AGGRESSIVE_TEST
1738 		ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
1739 #endif
1740 		return retval;
1741 	}
1742 
1743 	/*
1744 	 * Try to see if we can get the block without requesting a new
1745 	 * file system block.
1746 	 */
1747 	down_read(&EXT4_I(inode)->i_data_sem);
1748 	if (ext4_has_inline_data(inode))
1749 		retval = 0;
1750 	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
1751 		retval = ext4_ext_map_blocks(NULL, inode, map, 0);
1752 	else
1753 		retval = ext4_ind_map_blocks(NULL, inode, map, 0);
1754 
1755 add_delayed:
1756 	if (retval == 0) {
1757 		int ret;
1758 
1759 		/*
1760 		 * XXX: __block_prepare_write() unmaps passed block,
1761 		 * is it OK?
1762 		 */
1763 
1764 		ret = ext4_insert_delayed_block(inode, map->m_lblk);
1765 		if (ret != 0) {
1766 			retval = ret;
1767 			goto out_unlock;
1768 		}
1769 
1770 		map_bh(bh, inode->i_sb, invalid_block);
1771 		set_buffer_new(bh);
1772 		set_buffer_delay(bh);
1773 	} else if (retval > 0) {
1774 		unsigned int status;
1775 
1776 		if (unlikely(retval != map->m_len)) {
1777 			ext4_warning(inode->i_sb,
1778 				     "ES len assertion failed for inode "
1779 				     "%lu: retval %d != map->m_len %d",
1780 				     inode->i_ino, retval, map->m_len);
1781 			WARN_ON(1);
1782 		}
1783 
1784 		status = map->m_flags & EXT4_MAP_UNWRITTEN ?
1785 				EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
1786 		ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
1787 				      map->m_pblk, status);
1788 	}
1789 
1790 out_unlock:
1791 	up_read((&EXT4_I(inode)->i_data_sem));
1792 
1793 	return retval;
1794 }
1795 
1796 /*
1797  * This is a special get_block_t callback which is used by
1798  * ext4_da_write_begin().  It will either return mapped block or
1799  * reserve space for a single block.
1800  *
1801  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
1802  * We also have b_blocknr = -1 and b_bdev initialized properly
1803  *
1804  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
1805  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
1806  * initialized properly.
1807  */
ext4_da_get_block_prep(struct inode * inode,sector_t iblock,struct buffer_head * bh,int create)1808 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1809 			   struct buffer_head *bh, int create)
1810 {
1811 	struct ext4_map_blocks map;
1812 	int ret = 0;
1813 
1814 	BUG_ON(create == 0);
1815 	BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
1816 
1817 	map.m_lblk = iblock;
1818 	map.m_len = 1;
1819 
1820 	/*
1821 	 * first, we need to know whether the block is allocated already
1822 	 * preallocated blocks are unmapped but should treated
1823 	 * the same as allocated blocks.
1824 	 */
1825 	ret = ext4_da_map_blocks(inode, iblock, &map, bh);
1826 	if (ret <= 0)
1827 		return ret;
1828 
1829 	map_bh(bh, inode->i_sb, map.m_pblk);
1830 	ext4_update_bh_state(bh, map.m_flags);
1831 
1832 	if (buffer_unwritten(bh)) {
1833 		/* A delayed write to unwritten bh should be marked
1834 		 * new and mapped.  Mapped ensures that we don't do
1835 		 * get_block multiple times when we write to the same
1836 		 * offset and new ensures that we do proper zero out
1837 		 * for partial write.
1838 		 */
1839 		set_buffer_new(bh);
1840 		set_buffer_mapped(bh);
1841 	}
1842 	return 0;
1843 }
1844 
mpage_folio_done(struct mpage_da_data * mpd,struct folio * folio)1845 static void mpage_folio_done(struct mpage_da_data *mpd, struct folio *folio)
1846 {
1847 	mpd->first_page += folio_nr_pages(folio);
1848 	folio_unlock(folio);
1849 }
1850 
mpage_submit_folio(struct mpage_da_data * mpd,struct folio * folio)1851 static int mpage_submit_folio(struct mpage_da_data *mpd, struct folio *folio)
1852 {
1853 	size_t len;
1854 	loff_t size;
1855 	int err;
1856 
1857 	BUG_ON(folio->index != mpd->first_page);
1858 	folio_clear_dirty_for_io(folio);
1859 	/*
1860 	 * We have to be very careful here!  Nothing protects writeback path
1861 	 * against i_size changes and the page can be writeably mapped into
1862 	 * page tables. So an application can be growing i_size and writing
1863 	 * data through mmap while writeback runs. folio_clear_dirty_for_io()
1864 	 * write-protects our page in page tables and the page cannot get
1865 	 * written to again until we release folio lock. So only after
1866 	 * folio_clear_dirty_for_io() we are safe to sample i_size for
1867 	 * ext4_bio_write_folio() to zero-out tail of the written page. We rely
1868 	 * on the barrier provided by folio_test_clear_dirty() in
1869 	 * folio_clear_dirty_for_io() to make sure i_size is really sampled only
1870 	 * after page tables are updated.
1871 	 */
1872 	size = i_size_read(mpd->inode);
1873 	len = folio_size(folio);
1874 	if (folio_pos(folio) + len > size &&
1875 	    !ext4_verity_in_progress(mpd->inode))
1876 		len = size & ~PAGE_MASK;
1877 	err = ext4_bio_write_folio(&mpd->io_submit, folio, len);
1878 	if (!err)
1879 		mpd->wbc->nr_to_write--;
1880 
1881 	return err;
1882 }
1883 
1884 #define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
1885 
1886 /*
1887  * mballoc gives us at most this number of blocks...
1888  * XXX: That seems to be only a limitation of ext4_mb_normalize_request().
1889  * The rest of mballoc seems to handle chunks up to full group size.
1890  */
1891 #define MAX_WRITEPAGES_EXTENT_LEN 2048
1892 
1893 /*
1894  * mpage_add_bh_to_extent - try to add bh to extent of blocks to map
1895  *
1896  * @mpd - extent of blocks
1897  * @lblk - logical number of the block in the file
1898  * @bh - buffer head we want to add to the extent
1899  *
1900  * The function is used to collect contig. blocks in the same state. If the
1901  * buffer doesn't require mapping for writeback and we haven't started the
1902  * extent of buffers to map yet, the function returns 'true' immediately - the
1903  * caller can write the buffer right away. Otherwise the function returns true
1904  * if the block has been added to the extent, false if the block couldn't be
1905  * added.
1906  */
mpage_add_bh_to_extent(struct mpage_da_data * mpd,ext4_lblk_t lblk,struct buffer_head * bh)1907 static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
1908 				   struct buffer_head *bh)
1909 {
1910 	struct ext4_map_blocks *map = &mpd->map;
1911 
1912 	/* Buffer that doesn't need mapping for writeback? */
1913 	if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
1914 	    (!buffer_delay(bh) && !buffer_unwritten(bh))) {
1915 		/* So far no extent to map => we write the buffer right away */
1916 		if (map->m_len == 0)
1917 			return true;
1918 		return false;
1919 	}
1920 
1921 	/* First block in the extent? */
1922 	if (map->m_len == 0) {
1923 		/* We cannot map unless handle is started... */
1924 		if (!mpd->do_map)
1925 			return false;
1926 		map->m_lblk = lblk;
1927 		map->m_len = 1;
1928 		map->m_flags = bh->b_state & BH_FLAGS;
1929 		return true;
1930 	}
1931 
1932 	/* Don't go larger than mballoc is willing to allocate */
1933 	if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
1934 		return false;
1935 
1936 	/* Can we merge the block to our big extent? */
1937 	if (lblk == map->m_lblk + map->m_len &&
1938 	    (bh->b_state & BH_FLAGS) == map->m_flags) {
1939 		map->m_len++;
1940 		return true;
1941 	}
1942 	return false;
1943 }
1944 
1945 /*
1946  * mpage_process_page_bufs - submit page buffers for IO or add them to extent
1947  *
1948  * @mpd - extent of blocks for mapping
1949  * @head - the first buffer in the page
1950  * @bh - buffer we should start processing from
1951  * @lblk - logical number of the block in the file corresponding to @bh
1952  *
1953  * Walk through page buffers from @bh upto @head (exclusive) and either submit
1954  * the page for IO if all buffers in this page were mapped and there's no
1955  * accumulated extent of buffers to map or add buffers in the page to the
1956  * extent of buffers to map. The function returns 1 if the caller can continue
1957  * by processing the next page, 0 if it should stop adding buffers to the
1958  * extent to map because we cannot extend it anymore. It can also return value
1959  * < 0 in case of error during IO submission.
1960  */
mpage_process_page_bufs(struct mpage_da_data * mpd,struct buffer_head * head,struct buffer_head * bh,ext4_lblk_t lblk)1961 static int mpage_process_page_bufs(struct mpage_da_data *mpd,
1962 				   struct buffer_head *head,
1963 				   struct buffer_head *bh,
1964 				   ext4_lblk_t lblk)
1965 {
1966 	struct inode *inode = mpd->inode;
1967 	int err;
1968 	ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
1969 							>> inode->i_blkbits;
1970 
1971 	if (ext4_verity_in_progress(inode))
1972 		blocks = EXT_MAX_BLOCKS;
1973 
1974 	do {
1975 		BUG_ON(buffer_locked(bh));
1976 
1977 		if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
1978 			/* Found extent to map? */
1979 			if (mpd->map.m_len)
1980 				return 0;
1981 			/* Buffer needs mapping and handle is not started? */
1982 			if (!mpd->do_map)
1983 				return 0;
1984 			/* Everything mapped so far and we hit EOF */
1985 			break;
1986 		}
1987 	} while (lblk++, (bh = bh->b_this_page) != head);
1988 	/* So far everything mapped? Submit the page for IO. */
1989 	if (mpd->map.m_len == 0) {
1990 		err = mpage_submit_folio(mpd, head->b_folio);
1991 		if (err < 0)
1992 			return err;
1993 		mpage_folio_done(mpd, head->b_folio);
1994 	}
1995 	if (lblk >= blocks) {
1996 		mpd->scanned_until_end = 1;
1997 		return 0;
1998 	}
1999 	return 1;
2000 }
2001 
2002 /*
2003  * mpage_process_folio - update folio buffers corresponding to changed extent
2004  *			 and may submit fully mapped page for IO
2005  * @mpd: description of extent to map, on return next extent to map
2006  * @folio: Contains these buffers.
2007  * @m_lblk: logical block mapping.
2008  * @m_pblk: corresponding physical mapping.
2009  * @map_bh: determines on return whether this page requires any further
2010  *		  mapping or not.
2011  *
2012  * Scan given folio buffers corresponding to changed extent and update buffer
2013  * state according to new extent state.
2014  * We map delalloc buffers to their physical location, clear unwritten bits.
2015  * If the given folio is not fully mapped, we update @mpd to the next extent in
2016  * the given folio that needs mapping & return @map_bh as true.
2017  */
mpage_process_folio(struct mpage_da_data * mpd,struct folio * folio,ext4_lblk_t * m_lblk,ext4_fsblk_t * m_pblk,bool * map_bh)2018 static int mpage_process_folio(struct mpage_da_data *mpd, struct folio *folio,
2019 			      ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
2020 			      bool *map_bh)
2021 {
2022 	struct buffer_head *head, *bh;
2023 	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2024 	ext4_lblk_t lblk = *m_lblk;
2025 	ext4_fsblk_t pblock = *m_pblk;
2026 	int err = 0;
2027 	int blkbits = mpd->inode->i_blkbits;
2028 	ssize_t io_end_size = 0;
2029 	struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
2030 
2031 	bh = head = folio_buffers(folio);
2032 	do {
2033 		if (lblk < mpd->map.m_lblk)
2034 			continue;
2035 		if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
2036 			/*
2037 			 * Buffer after end of mapped extent.
2038 			 * Find next buffer in the folio to map.
2039 			 */
2040 			mpd->map.m_len = 0;
2041 			mpd->map.m_flags = 0;
2042 			io_end_vec->size += io_end_size;
2043 
2044 			err = mpage_process_page_bufs(mpd, head, bh, lblk);
2045 			if (err > 0)
2046 				err = 0;
2047 			if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
2048 				io_end_vec = ext4_alloc_io_end_vec(io_end);
2049 				if (IS_ERR(io_end_vec)) {
2050 					err = PTR_ERR(io_end_vec);
2051 					goto out;
2052 				}
2053 				io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
2054 			}
2055 			*map_bh = true;
2056 			goto out;
2057 		}
2058 		if (buffer_delay(bh)) {
2059 			clear_buffer_delay(bh);
2060 			bh->b_blocknr = pblock++;
2061 		}
2062 		clear_buffer_unwritten(bh);
2063 		io_end_size += (1 << blkbits);
2064 	} while (lblk++, (bh = bh->b_this_page) != head);
2065 
2066 	io_end_vec->size += io_end_size;
2067 	*map_bh = false;
2068 out:
2069 	*m_lblk = lblk;
2070 	*m_pblk = pblock;
2071 	return err;
2072 }
2073 
2074 /*
2075  * mpage_map_buffers - update buffers corresponding to changed extent and
2076  *		       submit fully mapped pages for IO
2077  *
2078  * @mpd - description of extent to map, on return next extent to map
2079  *
2080  * Scan buffers corresponding to changed extent (we expect corresponding pages
2081  * to be already locked) and update buffer state according to new extent state.
2082  * We map delalloc buffers to their physical location, clear unwritten bits,
2083  * and mark buffers as uninit when we perform writes to unwritten extents
2084  * and do extent conversion after IO is finished. If the last page is not fully
2085  * mapped, we update @map to the next extent in the last page that needs
2086  * mapping. Otherwise we submit the page for IO.
2087  */
mpage_map_and_submit_buffers(struct mpage_da_data * mpd)2088 static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
2089 {
2090 	struct folio_batch fbatch;
2091 	unsigned nr, i;
2092 	struct inode *inode = mpd->inode;
2093 	int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
2094 	pgoff_t start, end;
2095 	ext4_lblk_t lblk;
2096 	ext4_fsblk_t pblock;
2097 	int err;
2098 	bool map_bh = false;
2099 
2100 	start = mpd->map.m_lblk >> bpp_bits;
2101 	end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
2102 	lblk = start << bpp_bits;
2103 	pblock = mpd->map.m_pblk;
2104 
2105 	folio_batch_init(&fbatch);
2106 	while (start <= end) {
2107 		nr = filemap_get_folios(inode->i_mapping, &start, end, &fbatch);
2108 		if (nr == 0)
2109 			break;
2110 		for (i = 0; i < nr; i++) {
2111 			struct folio *folio = fbatch.folios[i];
2112 
2113 			err = mpage_process_folio(mpd, folio, &lblk, &pblock,
2114 						 &map_bh);
2115 			/*
2116 			 * If map_bh is true, means page may require further bh
2117 			 * mapping, or maybe the page was submitted for IO.
2118 			 * So we return to call further extent mapping.
2119 			 */
2120 			if (err < 0 || map_bh)
2121 				goto out;
2122 			/* Page fully mapped - let IO run! */
2123 			err = mpage_submit_folio(mpd, folio);
2124 			if (err < 0)
2125 				goto out;
2126 			mpage_folio_done(mpd, folio);
2127 		}
2128 		folio_batch_release(&fbatch);
2129 	}
2130 	/* Extent fully mapped and matches with page boundary. We are done. */
2131 	mpd->map.m_len = 0;
2132 	mpd->map.m_flags = 0;
2133 	return 0;
2134 out:
2135 	folio_batch_release(&fbatch);
2136 	return err;
2137 }
2138 
mpage_map_one_extent(handle_t * handle,struct mpage_da_data * mpd)2139 static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
2140 {
2141 	struct inode *inode = mpd->inode;
2142 	struct ext4_map_blocks *map = &mpd->map;
2143 	int get_blocks_flags;
2144 	int err, dioread_nolock;
2145 
2146 	trace_ext4_da_write_pages_extent(inode, map);
2147 	/*
2148 	 * Call ext4_map_blocks() to allocate any delayed allocation blocks, or
2149 	 * to convert an unwritten extent to be initialized (in the case
2150 	 * where we have written into one or more preallocated blocks).  It is
2151 	 * possible that we're going to need more metadata blocks than
2152 	 * previously reserved. However we must not fail because we're in
2153 	 * writeback and there is nothing we can do about it so it might result
2154 	 * in data loss.  So use reserved blocks to allocate metadata if
2155 	 * possible.
2156 	 *
2157 	 * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
2158 	 * the blocks in question are delalloc blocks.  This indicates
2159 	 * that the blocks and quotas has already been checked when
2160 	 * the data was copied into the page cache.
2161 	 */
2162 	get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
2163 			   EXT4_GET_BLOCKS_METADATA_NOFAIL |
2164 			   EXT4_GET_BLOCKS_IO_SUBMIT;
2165 	dioread_nolock = ext4_should_dioread_nolock(inode);
2166 	if (dioread_nolock)
2167 		get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
2168 	if (map->m_flags & BIT(BH_Delay))
2169 		get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
2170 
2171 	err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
2172 	if (err < 0)
2173 		return err;
2174 	if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
2175 		if (!mpd->io_submit.io_end->handle &&
2176 		    ext4_handle_valid(handle)) {
2177 			mpd->io_submit.io_end->handle = handle->h_rsv_handle;
2178 			handle->h_rsv_handle = NULL;
2179 		}
2180 		ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
2181 	}
2182 
2183 	BUG_ON(map->m_len == 0);
2184 	return 0;
2185 }
2186 
2187 /*
2188  * mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
2189  *				 mpd->len and submit pages underlying it for IO
2190  *
2191  * @handle - handle for journal operations
2192  * @mpd - extent to map
2193  * @give_up_on_write - we set this to true iff there is a fatal error and there
2194  *                     is no hope of writing the data. The caller should discard
2195  *                     dirty pages to avoid infinite loops.
2196  *
2197  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
2198  * delayed, blocks are allocated, if it is unwritten, we may need to convert
2199  * them to initialized or split the described range from larger unwritten
2200  * extent. Note that we need not map all the described range since allocation
2201  * can return less blocks or the range is covered by more unwritten extents. We
2202  * cannot map more because we are limited by reserved transaction credits. On
2203  * the other hand we always make sure that the last touched page is fully
2204  * mapped so that it can be written out (and thus forward progress is
2205  * guaranteed). After mapping we submit all mapped pages for IO.
2206  */
mpage_map_and_submit_extent(handle_t * handle,struct mpage_da_data * mpd,bool * give_up_on_write)2207 static int mpage_map_and_submit_extent(handle_t *handle,
2208 				       struct mpage_da_data *mpd,
2209 				       bool *give_up_on_write)
2210 {
2211 	struct inode *inode = mpd->inode;
2212 	struct ext4_map_blocks *map = &mpd->map;
2213 	int err;
2214 	loff_t disksize;
2215 	int progress = 0;
2216 	ext4_io_end_t *io_end = mpd->io_submit.io_end;
2217 	struct ext4_io_end_vec *io_end_vec;
2218 
2219 	io_end_vec = ext4_alloc_io_end_vec(io_end);
2220 	if (IS_ERR(io_end_vec))
2221 		return PTR_ERR(io_end_vec);
2222 	io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
2223 	do {
2224 		err = mpage_map_one_extent(handle, mpd);
2225 		if (err < 0) {
2226 			struct super_block *sb = inode->i_sb;
2227 
2228 			if (ext4_forced_shutdown(sb))
2229 				goto invalidate_dirty_pages;
2230 			/*
2231 			 * Let the uper layers retry transient errors.
2232 			 * In the case of ENOSPC, if ext4_count_free_blocks()
2233 			 * is non-zero, a commit should free up blocks.
2234 			 */
2235 			if ((err == -ENOMEM) ||
2236 			    (err == -ENOSPC && ext4_count_free_clusters(sb))) {
2237 				if (progress)
2238 					goto update_disksize;
2239 				return err;
2240 			}
2241 			ext4_msg(sb, KERN_CRIT,
2242 				 "Delayed block allocation failed for "
2243 				 "inode %lu at logical offset %llu with"
2244 				 " max blocks %u with error %d",
2245 				 inode->i_ino,
2246 				 (unsigned long long)map->m_lblk,
2247 				 (unsigned)map->m_len, -err);
2248 			ext4_msg(sb, KERN_CRIT,
2249 				 "This should not happen!! Data will "
2250 				 "be lost\n");
2251 			if (err == -ENOSPC)
2252 				ext4_print_free_blocks(inode);
2253 		invalidate_dirty_pages:
2254 			*give_up_on_write = true;
2255 			return err;
2256 		}
2257 		progress = 1;
2258 		/*
2259 		 * Update buffer state, submit mapped pages, and get us new
2260 		 * extent to map
2261 		 */
2262 		err = mpage_map_and_submit_buffers(mpd);
2263 		if (err < 0)
2264 			goto update_disksize;
2265 	} while (map->m_len);
2266 
2267 update_disksize:
2268 	/*
2269 	 * Update on-disk size after IO is submitted.  Races with
2270 	 * truncate are avoided by checking i_size under i_data_sem.
2271 	 */
2272 	disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
2273 	if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
2274 		int err2;
2275 		loff_t i_size;
2276 
2277 		down_write(&EXT4_I(inode)->i_data_sem);
2278 		i_size = i_size_read(inode);
2279 		if (disksize > i_size)
2280 			disksize = i_size;
2281 		if (disksize > EXT4_I(inode)->i_disksize)
2282 			EXT4_I(inode)->i_disksize = disksize;
2283 		up_write(&EXT4_I(inode)->i_data_sem);
2284 		err2 = ext4_mark_inode_dirty(handle, inode);
2285 		if (err2) {
2286 			ext4_error_err(inode->i_sb, -err2,
2287 				       "Failed to mark inode %lu dirty",
2288 				       inode->i_ino);
2289 		}
2290 		if (!err)
2291 			err = err2;
2292 	}
2293 	return err;
2294 }
2295 
2296 /*
2297  * Calculate the total number of credits to reserve for one writepages
2298  * iteration. This is called from ext4_writepages(). We map an extent of
2299  * up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
2300  * the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
2301  * bpp - 1 blocks in bpp different extents.
2302  */
ext4_da_writepages_trans_blocks(struct inode * inode)2303 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2304 {
2305 	int bpp = ext4_journal_blocks_per_page(inode);
2306 
2307 	return ext4_meta_trans_blocks(inode,
2308 				MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
2309 }
2310 
ext4_journal_folio_buffers(handle_t * handle,struct folio * folio,size_t len)2311 static int ext4_journal_folio_buffers(handle_t *handle, struct folio *folio,
2312 				     size_t len)
2313 {
2314 	struct buffer_head *page_bufs = folio_buffers(folio);
2315 	struct inode *inode = folio->mapping->host;
2316 	int ret, err;
2317 
2318 	ret = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
2319 				     NULL, do_journal_get_write_access);
2320 	err = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
2321 				     NULL, write_end_fn);
2322 	if (ret == 0)
2323 		ret = err;
2324 	err = ext4_jbd2_inode_add_write(handle, inode, folio_pos(folio), len);
2325 	if (ret == 0)
2326 		ret = err;
2327 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
2328 
2329 	return ret;
2330 }
2331 
mpage_journal_page_buffers(handle_t * handle,struct mpage_da_data * mpd,struct folio * folio)2332 static int mpage_journal_page_buffers(handle_t *handle,
2333 				      struct mpage_da_data *mpd,
2334 				      struct folio *folio)
2335 {
2336 	struct inode *inode = mpd->inode;
2337 	loff_t size = i_size_read(inode);
2338 	size_t len = folio_size(folio);
2339 
2340 	folio_clear_checked(folio);
2341 	mpd->wbc->nr_to_write--;
2342 
2343 	if (folio_pos(folio) + len > size &&
2344 	    !ext4_verity_in_progress(inode))
2345 		len = size - folio_pos(folio);
2346 
2347 	return ext4_journal_folio_buffers(handle, folio, len);
2348 }
2349 
2350 /*
2351  * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
2352  * 				 needing mapping, submit mapped pages
2353  *
2354  * @mpd - where to look for pages
2355  *
2356  * Walk dirty pages in the mapping. If they are fully mapped, submit them for
2357  * IO immediately. If we cannot map blocks, we submit just already mapped
2358  * buffers in the page for IO and keep page dirty. When we can map blocks and
2359  * we find a page which isn't mapped we start accumulating extent of buffers
2360  * underlying these pages that needs mapping (formed by either delayed or
2361  * unwritten buffers). We also lock the pages containing these buffers. The
2362  * extent found is returned in @mpd structure (starting at mpd->lblk with
2363  * length mpd->len blocks).
2364  *
2365  * Note that this function can attach bios to one io_end structure which are
2366  * neither logically nor physically contiguous. Although it may seem as an
2367  * unnecessary complication, it is actually inevitable in blocksize < pagesize
2368  * case as we need to track IO to all buffers underlying a page in one io_end.
2369  */
mpage_prepare_extent_to_map(struct mpage_da_data * mpd)2370 static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
2371 {
2372 	struct address_space *mapping = mpd->inode->i_mapping;
2373 	struct folio_batch fbatch;
2374 	unsigned int nr_folios;
2375 	pgoff_t index = mpd->first_page;
2376 	pgoff_t end = mpd->last_page;
2377 	xa_mark_t tag;
2378 	int i, err = 0;
2379 	int blkbits = mpd->inode->i_blkbits;
2380 	ext4_lblk_t lblk;
2381 	struct buffer_head *head;
2382 	handle_t *handle = NULL;
2383 	int bpp = ext4_journal_blocks_per_page(mpd->inode);
2384 
2385 	if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
2386 		tag = PAGECACHE_TAG_TOWRITE;
2387 	else
2388 		tag = PAGECACHE_TAG_DIRTY;
2389 
2390 	mpd->map.m_len = 0;
2391 	mpd->next_page = index;
2392 	if (ext4_should_journal_data(mpd->inode)) {
2393 		handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,
2394 					    bpp);
2395 		if (IS_ERR(handle))
2396 			return PTR_ERR(handle);
2397 	}
2398 	folio_batch_init(&fbatch);
2399 	while (index <= end) {
2400 		nr_folios = filemap_get_folios_tag(mapping, &index, end,
2401 				tag, &fbatch);
2402 		if (nr_folios == 0)
2403 			break;
2404 
2405 		for (i = 0; i < nr_folios; i++) {
2406 			struct folio *folio = fbatch.folios[i];
2407 
2408 			/*
2409 			 * Accumulated enough dirty pages? This doesn't apply
2410 			 * to WB_SYNC_ALL mode. For integrity sync we have to
2411 			 * keep going because someone may be concurrently
2412 			 * dirtying pages, and we might have synced a lot of
2413 			 * newly appeared dirty pages, but have not synced all
2414 			 * of the old dirty pages.
2415 			 */
2416 			if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
2417 			    mpd->wbc->nr_to_write <=
2418 			    mpd->map.m_len >> (PAGE_SHIFT - blkbits))
2419 				goto out;
2420 
2421 			/* If we can't merge this page, we are done. */
2422 			if (mpd->map.m_len > 0 && mpd->next_page != folio->index)
2423 				goto out;
2424 
2425 			if (handle) {
2426 				err = ext4_journal_ensure_credits(handle, bpp,
2427 								  0);
2428 				if (err < 0)
2429 					goto out;
2430 			}
2431 
2432 			folio_lock(folio);
2433 			/*
2434 			 * If the page is no longer dirty, or its mapping no
2435 			 * longer corresponds to inode we are writing (which
2436 			 * means it has been truncated or invalidated), or the
2437 			 * page is already under writeback and we are not doing
2438 			 * a data integrity writeback, skip the page
2439 			 */
2440 			if (!folio_test_dirty(folio) ||
2441 			    (folio_test_writeback(folio) &&
2442 			     (mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
2443 			    unlikely(folio->mapping != mapping)) {
2444 				folio_unlock(folio);
2445 				continue;
2446 			}
2447 
2448 			folio_wait_writeback(folio);
2449 			BUG_ON(folio_test_writeback(folio));
2450 
2451 			/*
2452 			 * Should never happen but for buggy code in
2453 			 * other subsystems that call
2454 			 * set_page_dirty() without properly warning
2455 			 * the file system first.  See [1] for more
2456 			 * information.
2457 			 *
2458 			 * [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
2459 			 */
2460 			if (!folio_buffers(folio)) {
2461 				ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", folio->index);
2462 				folio_clear_dirty(folio);
2463 				folio_unlock(folio);
2464 				continue;
2465 			}
2466 
2467 			if (mpd->map.m_len == 0)
2468 				mpd->first_page = folio->index;
2469 			mpd->next_page = folio_next_index(folio);
2470 			/*
2471 			 * Writeout when we cannot modify metadata is simple.
2472 			 * Just submit the page. For data=journal mode we
2473 			 * first handle writeout of the page for checkpoint and
2474 			 * only after that handle delayed page dirtying. This
2475 			 * makes sure current data is checkpointed to the final
2476 			 * location before possibly journalling it again which
2477 			 * is desirable when the page is frequently dirtied
2478 			 * through a pin.
2479 			 */
2480 			if (!mpd->can_map) {
2481 				err = mpage_submit_folio(mpd, folio);
2482 				if (err < 0)
2483 					goto out;
2484 				/* Pending dirtying of journalled data? */
2485 				if (folio_test_checked(folio)) {
2486 					err = mpage_journal_page_buffers(handle,
2487 						mpd, folio);
2488 					if (err < 0)
2489 						goto out;
2490 					mpd->journalled_more_data = 1;
2491 				}
2492 				mpage_folio_done(mpd, folio);
2493 			} else {
2494 				/* Add all dirty buffers to mpd */
2495 				lblk = ((ext4_lblk_t)folio->index) <<
2496 					(PAGE_SHIFT - blkbits);
2497 				head = folio_buffers(folio);
2498 				err = mpage_process_page_bufs(mpd, head, head,
2499 						lblk);
2500 				if (err <= 0)
2501 					goto out;
2502 				err = 0;
2503 			}
2504 		}
2505 		folio_batch_release(&fbatch);
2506 		cond_resched();
2507 	}
2508 	mpd->scanned_until_end = 1;
2509 	if (handle)
2510 		ext4_journal_stop(handle);
2511 	return 0;
2512 out:
2513 	folio_batch_release(&fbatch);
2514 	if (handle)
2515 		ext4_journal_stop(handle);
2516 	return err;
2517 }
2518 
ext4_do_writepages(struct mpage_da_data * mpd)2519 static int ext4_do_writepages(struct mpage_da_data *mpd)
2520 {
2521 	struct writeback_control *wbc = mpd->wbc;
2522 	pgoff_t	writeback_index = 0;
2523 	long nr_to_write = wbc->nr_to_write;
2524 	int range_whole = 0;
2525 	int cycled = 1;
2526 	handle_t *handle = NULL;
2527 	struct inode *inode = mpd->inode;
2528 	struct address_space *mapping = inode->i_mapping;
2529 	int needed_blocks, rsv_blocks = 0, ret = 0;
2530 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2531 	struct blk_plug plug;
2532 	bool give_up_on_write = false;
2533 
2534 	trace_ext4_writepages(inode, wbc);
2535 
2536 	/*
2537 	 * No pages to write? This is mainly a kludge to avoid starting
2538 	 * a transaction for special inodes like journal inode on last iput()
2539 	 * because that could violate lock ordering on umount
2540 	 */
2541 	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2542 		goto out_writepages;
2543 
2544 	/*
2545 	 * If the filesystem has aborted, it is read-only, so return
2546 	 * right away instead of dumping stack traces later on that
2547 	 * will obscure the real source of the problem.  We test
2548 	 * fs shutdown state instead of sb->s_flag's SB_RDONLY because
2549 	 * the latter could be true if the filesystem is mounted
2550 	 * read-only, and in that case, ext4_writepages should
2551 	 * *never* be called, so if that ever happens, we would want
2552 	 * the stack trace.
2553 	 */
2554 	if (unlikely(ext4_forced_shutdown(mapping->host->i_sb))) {
2555 		ret = -EROFS;
2556 		goto out_writepages;
2557 	}
2558 
2559 	/*
2560 	 * If we have inline data and arrive here, it means that
2561 	 * we will soon create the block for the 1st page, so
2562 	 * we'd better clear the inline data here.
2563 	 */
2564 	if (ext4_has_inline_data(inode)) {
2565 		/* Just inode will be modified... */
2566 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
2567 		if (IS_ERR(handle)) {
2568 			ret = PTR_ERR(handle);
2569 			goto out_writepages;
2570 		}
2571 		BUG_ON(ext4_test_inode_state(inode,
2572 				EXT4_STATE_MAY_INLINE_DATA));
2573 		ext4_destroy_inline_data(handle, inode);
2574 		ext4_journal_stop(handle);
2575 	}
2576 
2577 	/*
2578 	 * data=journal mode does not do delalloc so we just need to writeout /
2579 	 * journal already mapped buffers. On the other hand we need to commit
2580 	 * transaction to make data stable. We expect all the data to be
2581 	 * already in the journal (the only exception are DMA pinned pages
2582 	 * dirtied behind our back) so we commit transaction here and run the
2583 	 * writeback loop to checkpoint them. The checkpointing is not actually
2584 	 * necessary to make data persistent *but* quite a few places (extent
2585 	 * shifting operations, fsverity, ...) depend on being able to drop
2586 	 * pagecache pages after calling filemap_write_and_wait() and for that
2587 	 * checkpointing needs to happen.
2588 	 */
2589 	if (ext4_should_journal_data(inode)) {
2590 		mpd->can_map = 0;
2591 		if (wbc->sync_mode == WB_SYNC_ALL)
2592 			ext4_fc_commit(sbi->s_journal,
2593 				       EXT4_I(inode)->i_datasync_tid);
2594 	}
2595 	mpd->journalled_more_data = 0;
2596 
2597 	if (ext4_should_dioread_nolock(inode)) {
2598 		/*
2599 		 * We may need to convert up to one extent per block in
2600 		 * the page and we may dirty the inode.
2601 		 */
2602 		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
2603 						PAGE_SIZE >> inode->i_blkbits);
2604 	}
2605 
2606 	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2607 		range_whole = 1;
2608 
2609 	if (wbc->range_cyclic) {
2610 		writeback_index = mapping->writeback_index;
2611 		if (writeback_index)
2612 			cycled = 0;
2613 		mpd->first_page = writeback_index;
2614 		mpd->last_page = -1;
2615 	} else {
2616 		mpd->first_page = wbc->range_start >> PAGE_SHIFT;
2617 		mpd->last_page = wbc->range_end >> PAGE_SHIFT;
2618 	}
2619 
2620 	ext4_io_submit_init(&mpd->io_submit, wbc);
2621 retry:
2622 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
2623 		tag_pages_for_writeback(mapping, mpd->first_page,
2624 					mpd->last_page);
2625 	blk_start_plug(&plug);
2626 
2627 	/*
2628 	 * First writeback pages that don't need mapping - we can avoid
2629 	 * starting a transaction unnecessarily and also avoid being blocked
2630 	 * in the block layer on device congestion while having transaction
2631 	 * started.
2632 	 */
2633 	mpd->do_map = 0;
2634 	mpd->scanned_until_end = 0;
2635 	mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2636 	if (!mpd->io_submit.io_end) {
2637 		ret = -ENOMEM;
2638 		goto unplug;
2639 	}
2640 	ret = mpage_prepare_extent_to_map(mpd);
2641 	/* Unlock pages we didn't use */
2642 	mpage_release_unused_pages(mpd, false);
2643 	/* Submit prepared bio */
2644 	ext4_io_submit(&mpd->io_submit);
2645 	ext4_put_io_end_defer(mpd->io_submit.io_end);
2646 	mpd->io_submit.io_end = NULL;
2647 	if (ret < 0)
2648 		goto unplug;
2649 
2650 	while (!mpd->scanned_until_end && wbc->nr_to_write > 0) {
2651 		/* For each extent of pages we use new io_end */
2652 		mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
2653 		if (!mpd->io_submit.io_end) {
2654 			ret = -ENOMEM;
2655 			break;
2656 		}
2657 
2658 		WARN_ON_ONCE(!mpd->can_map);
2659 		/*
2660 		 * We have two constraints: We find one extent to map and we
2661 		 * must always write out whole page (makes a difference when
2662 		 * blocksize < pagesize) so that we don't block on IO when we
2663 		 * try to write out the rest of the page. Journalled mode is
2664 		 * not supported by delalloc.
2665 		 */
2666 		BUG_ON(ext4_should_journal_data(inode));
2667 		needed_blocks = ext4_da_writepages_trans_blocks(inode);
2668 
2669 		/* start a new transaction */
2670 		handle = ext4_journal_start_with_reserve(inode,
2671 				EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
2672 		if (IS_ERR(handle)) {
2673 			ret = PTR_ERR(handle);
2674 			ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2675 			       "%ld pages, ino %lu; err %d", __func__,
2676 				wbc->nr_to_write, inode->i_ino, ret);
2677 			/* Release allocated io_end */
2678 			ext4_put_io_end(mpd->io_submit.io_end);
2679 			mpd->io_submit.io_end = NULL;
2680 			break;
2681 		}
2682 		mpd->do_map = 1;
2683 
2684 		trace_ext4_da_write_pages(inode, mpd->first_page, wbc);
2685 		ret = mpage_prepare_extent_to_map(mpd);
2686 		if (!ret && mpd->map.m_len)
2687 			ret = mpage_map_and_submit_extent(handle, mpd,
2688 					&give_up_on_write);
2689 		/*
2690 		 * Caution: If the handle is synchronous,
2691 		 * ext4_journal_stop() can wait for transaction commit
2692 		 * to finish which may depend on writeback of pages to
2693 		 * complete or on page lock to be released.  In that
2694 		 * case, we have to wait until after we have
2695 		 * submitted all the IO, released page locks we hold,
2696 		 * and dropped io_end reference (for extent conversion
2697 		 * to be able to complete) before stopping the handle.
2698 		 */
2699 		if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
2700 			ext4_journal_stop(handle);
2701 			handle = NULL;
2702 			mpd->do_map = 0;
2703 		}
2704 		/* Unlock pages we didn't use */
2705 		mpage_release_unused_pages(mpd, give_up_on_write);
2706 		/* Submit prepared bio */
2707 		ext4_io_submit(&mpd->io_submit);
2708 
2709 		/*
2710 		 * Drop our io_end reference we got from init. We have
2711 		 * to be careful and use deferred io_end finishing if
2712 		 * we are still holding the transaction as we can
2713 		 * release the last reference to io_end which may end
2714 		 * up doing unwritten extent conversion.
2715 		 */
2716 		if (handle) {
2717 			ext4_put_io_end_defer(mpd->io_submit.io_end);
2718 			ext4_journal_stop(handle);
2719 		} else
2720 			ext4_put_io_end(mpd->io_submit.io_end);
2721 		mpd->io_submit.io_end = NULL;
2722 
2723 		if (ret == -ENOSPC && sbi->s_journal) {
2724 			/*
2725 			 * Commit the transaction which would
2726 			 * free blocks released in the transaction
2727 			 * and try again
2728 			 */
2729 			jbd2_journal_force_commit_nested(sbi->s_journal);
2730 			ret = 0;
2731 			continue;
2732 		}
2733 		/* Fatal error - ENOMEM, EIO... */
2734 		if (ret)
2735 			break;
2736 	}
2737 unplug:
2738 	blk_finish_plug(&plug);
2739 	if (!ret && !cycled && wbc->nr_to_write > 0) {
2740 		cycled = 1;
2741 		mpd->last_page = writeback_index - 1;
2742 		mpd->first_page = 0;
2743 		goto retry;
2744 	}
2745 
2746 	/* Update index */
2747 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2748 		/*
2749 		 * Set the writeback_index so that range_cyclic
2750 		 * mode will write it back later
2751 		 */
2752 		mapping->writeback_index = mpd->first_page;
2753 
2754 out_writepages:
2755 	trace_ext4_writepages_result(inode, wbc, ret,
2756 				     nr_to_write - wbc->nr_to_write);
2757 	return ret;
2758 }
2759 
ext4_writepages(struct address_space * mapping,struct writeback_control * wbc)2760 static int ext4_writepages(struct address_space *mapping,
2761 			   struct writeback_control *wbc)
2762 {
2763 	struct super_block *sb = mapping->host->i_sb;
2764 	struct mpage_da_data mpd = {
2765 		.inode = mapping->host,
2766 		.wbc = wbc,
2767 		.can_map = 1,
2768 	};
2769 	int ret;
2770 	int alloc_ctx;
2771 
2772 	if (unlikely(ext4_forced_shutdown(sb)))
2773 		return -EIO;
2774 
2775 	alloc_ctx = ext4_writepages_down_read(sb);
2776 	ret = ext4_do_writepages(&mpd);
2777 	/*
2778 	 * For data=journal writeback we could have come across pages marked
2779 	 * for delayed dirtying (PageChecked) which were just added to the
2780 	 * running transaction. Try once more to get them to stable storage.
2781 	 */
2782 	if (!ret && mpd.journalled_more_data)
2783 		ret = ext4_do_writepages(&mpd);
2784 	ext4_writepages_up_read(sb, alloc_ctx);
2785 
2786 	return ret;
2787 }
2788 
ext4_normal_submit_inode_data_buffers(struct jbd2_inode * jinode)2789 int ext4_normal_submit_inode_data_buffers(struct jbd2_inode *jinode)
2790 {
2791 	struct writeback_control wbc = {
2792 		.sync_mode = WB_SYNC_ALL,
2793 		.nr_to_write = LONG_MAX,
2794 		.range_start = jinode->i_dirty_start,
2795 		.range_end = jinode->i_dirty_end,
2796 	};
2797 	struct mpage_da_data mpd = {
2798 		.inode = jinode->i_vfs_inode,
2799 		.wbc = &wbc,
2800 		.can_map = 0,
2801 	};
2802 	return ext4_do_writepages(&mpd);
2803 }
2804 
ext4_dax_writepages(struct address_space * mapping,struct writeback_control * wbc)2805 static int ext4_dax_writepages(struct address_space *mapping,
2806 			       struct writeback_control *wbc)
2807 {
2808 	int ret;
2809 	long nr_to_write = wbc->nr_to_write;
2810 	struct inode *inode = mapping->host;
2811 	int alloc_ctx;
2812 
2813 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
2814 		return -EIO;
2815 
2816 	alloc_ctx = ext4_writepages_down_read(inode->i_sb);
2817 	trace_ext4_writepages(inode, wbc);
2818 
2819 	ret = dax_writeback_mapping_range(mapping,
2820 					  EXT4_SB(inode->i_sb)->s_daxdev, wbc);
2821 	trace_ext4_writepages_result(inode, wbc, ret,
2822 				     nr_to_write - wbc->nr_to_write);
2823 	ext4_writepages_up_read(inode->i_sb, alloc_ctx);
2824 	return ret;
2825 }
2826 
ext4_nonda_switch(struct super_block * sb)2827 static int ext4_nonda_switch(struct super_block *sb)
2828 {
2829 	s64 free_clusters, dirty_clusters;
2830 	struct ext4_sb_info *sbi = EXT4_SB(sb);
2831 
2832 	/*
2833 	 * switch to non delalloc mode if we are running low
2834 	 * on free block. The free block accounting via percpu
2835 	 * counters can get slightly wrong with percpu_counter_batch getting
2836 	 * accumulated on each CPU without updating global counters
2837 	 * Delalloc need an accurate free block accounting. So switch
2838 	 * to non delalloc when we are near to error range.
2839 	 */
2840 	free_clusters =
2841 		percpu_counter_read_positive(&sbi->s_freeclusters_counter);
2842 	dirty_clusters =
2843 		percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
2844 	/*
2845 	 * Start pushing delalloc when 1/2 of free blocks are dirty.
2846 	 */
2847 	if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
2848 		try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
2849 
2850 	if (2 * free_clusters < 3 * dirty_clusters ||
2851 	    free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
2852 		/*
2853 		 * free block count is less than 150% of dirty blocks
2854 		 * or free blocks is less than watermark
2855 		 */
2856 		return 1;
2857 	}
2858 	return 0;
2859 }
2860 
ext4_da_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)2861 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2862 			       loff_t pos, unsigned len,
2863 			       struct page **pagep, void **fsdata)
2864 {
2865 	int ret, retries = 0;
2866 	struct folio *folio;
2867 	pgoff_t index;
2868 	struct inode *inode = mapping->host;
2869 
2870 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
2871 		return -EIO;
2872 
2873 	index = pos >> PAGE_SHIFT;
2874 
2875 	if (ext4_nonda_switch(inode->i_sb) || ext4_verity_in_progress(inode)) {
2876 		*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
2877 		return ext4_write_begin(file, mapping, pos,
2878 					len, pagep, fsdata);
2879 	}
2880 	*fsdata = (void *)0;
2881 	trace_ext4_da_write_begin(inode, pos, len);
2882 
2883 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
2884 		ret = ext4_da_write_inline_data_begin(mapping, inode, pos, len,
2885 						      pagep, fsdata);
2886 		if (ret < 0)
2887 			return ret;
2888 		if (ret == 1)
2889 			return 0;
2890 	}
2891 
2892 retry:
2893 	folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
2894 			mapping_gfp_mask(mapping));
2895 	if (IS_ERR(folio))
2896 		return PTR_ERR(folio);
2897 
2898 	/* In case writeback began while the folio was unlocked */
2899 	folio_wait_stable(folio);
2900 
2901 #ifdef CONFIG_FS_ENCRYPTION
2902 	ret = ext4_block_write_begin(folio, pos, len, ext4_da_get_block_prep);
2903 #else
2904 	ret = __block_write_begin(&folio->page, pos, len, ext4_da_get_block_prep);
2905 #endif
2906 	if (ret < 0) {
2907 		folio_unlock(folio);
2908 		folio_put(folio);
2909 		/*
2910 		 * block_write_begin may have instantiated a few blocks
2911 		 * outside i_size.  Trim these off again. Don't need
2912 		 * i_size_read because we hold inode lock.
2913 		 */
2914 		if (pos + len > inode->i_size)
2915 			ext4_truncate_failed_write(inode);
2916 
2917 		if (ret == -ENOSPC &&
2918 		    ext4_should_retry_alloc(inode->i_sb, &retries))
2919 			goto retry;
2920 		return ret;
2921 	}
2922 
2923 	*pagep = &folio->page;
2924 	return ret;
2925 }
2926 
2927 /*
2928  * Check if we should update i_disksize
2929  * when write to the end of file but not require block allocation
2930  */
ext4_da_should_update_i_disksize(struct folio * folio,unsigned long offset)2931 static int ext4_da_should_update_i_disksize(struct folio *folio,
2932 					    unsigned long offset)
2933 {
2934 	struct buffer_head *bh;
2935 	struct inode *inode = folio->mapping->host;
2936 	unsigned int idx;
2937 	int i;
2938 
2939 	bh = folio_buffers(folio);
2940 	idx = offset >> inode->i_blkbits;
2941 
2942 	for (i = 0; i < idx; i++)
2943 		bh = bh->b_this_page;
2944 
2945 	if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
2946 		return 0;
2947 	return 1;
2948 }
2949 
ext4_da_do_write_end(struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page)2950 static int ext4_da_do_write_end(struct address_space *mapping,
2951 			loff_t pos, unsigned len, unsigned copied,
2952 			struct page *page)
2953 {
2954 	struct inode *inode = mapping->host;
2955 	loff_t old_size = inode->i_size;
2956 	bool disksize_changed = false;
2957 	loff_t new_i_size;
2958 
2959 	/*
2960 	 * block_write_end() will mark the inode as dirty with I_DIRTY_PAGES
2961 	 * flag, which all that's needed to trigger page writeback.
2962 	 */
2963 	copied = block_write_end(NULL, mapping, pos, len, copied, page, NULL);
2964 	new_i_size = pos + copied;
2965 
2966 	/*
2967 	 * It's important to update i_size while still holding page lock,
2968 	 * because page writeout could otherwise come in and zero beyond
2969 	 * i_size.
2970 	 *
2971 	 * Since we are holding inode lock, we are sure i_disksize <=
2972 	 * i_size. We also know that if i_disksize < i_size, there are
2973 	 * delalloc writes pending in the range up to i_size. If the end of
2974 	 * the current write is <= i_size, there's no need to touch
2975 	 * i_disksize since writeback will push i_disksize up to i_size
2976 	 * eventually. If the end of the current write is > i_size and
2977 	 * inside an allocated block which ext4_da_should_update_i_disksize()
2978 	 * checked, we need to update i_disksize here as certain
2979 	 * ext4_writepages() paths not allocating blocks and update i_disksize.
2980 	 */
2981 	if (new_i_size > inode->i_size) {
2982 		unsigned long end;
2983 
2984 		i_size_write(inode, new_i_size);
2985 		end = (new_i_size - 1) & (PAGE_SIZE - 1);
2986 		if (copied && ext4_da_should_update_i_disksize(page_folio(page), end)) {
2987 			ext4_update_i_disksize(inode, new_i_size);
2988 			disksize_changed = true;
2989 		}
2990 	}
2991 
2992 	unlock_page(page);
2993 	put_page(page);
2994 
2995 	if (old_size < pos)
2996 		pagecache_isize_extended(inode, old_size, pos);
2997 
2998 	if (disksize_changed) {
2999 		handle_t *handle;
3000 
3001 		handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
3002 		if (IS_ERR(handle))
3003 			return PTR_ERR(handle);
3004 		ext4_mark_inode_dirty(handle, inode);
3005 		ext4_journal_stop(handle);
3006 	}
3007 
3008 	return copied;
3009 }
3010 
ext4_da_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)3011 static int ext4_da_write_end(struct file *file,
3012 			     struct address_space *mapping,
3013 			     loff_t pos, unsigned len, unsigned copied,
3014 			     struct page *page, void *fsdata)
3015 {
3016 	struct inode *inode = mapping->host;
3017 	int write_mode = (int)(unsigned long)fsdata;
3018 	struct folio *folio = page_folio(page);
3019 
3020 	if (write_mode == FALL_BACK_TO_NONDELALLOC)
3021 		return ext4_write_end(file, mapping, pos,
3022 				      len, copied, &folio->page, fsdata);
3023 
3024 	trace_ext4_da_write_end(inode, pos, len, copied);
3025 
3026 	if (write_mode != CONVERT_INLINE_DATA &&
3027 	    ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) &&
3028 	    ext4_has_inline_data(inode))
3029 		return ext4_write_inline_data_end(inode, pos, len, copied,
3030 						  folio);
3031 
3032 	if (unlikely(copied < len) && !PageUptodate(page))
3033 		copied = 0;
3034 
3035 	return ext4_da_do_write_end(mapping, pos, len, copied, &folio->page);
3036 }
3037 
3038 /*
3039  * Force all delayed allocation blocks to be allocated for a given inode.
3040  */
ext4_alloc_da_blocks(struct inode * inode)3041 int ext4_alloc_da_blocks(struct inode *inode)
3042 {
3043 	trace_ext4_alloc_da_blocks(inode);
3044 
3045 	if (!EXT4_I(inode)->i_reserved_data_blocks)
3046 		return 0;
3047 
3048 	/*
3049 	 * We do something simple for now.  The filemap_flush() will
3050 	 * also start triggering a write of the data blocks, which is
3051 	 * not strictly speaking necessary (and for users of
3052 	 * laptop_mode, not even desirable).  However, to do otherwise
3053 	 * would require replicating code paths in:
3054 	 *
3055 	 * ext4_writepages() ->
3056 	 *    write_cache_pages() ---> (via passed in callback function)
3057 	 *        __mpage_da_writepage() -->
3058 	 *           mpage_add_bh_to_extent()
3059 	 *           mpage_da_map_blocks()
3060 	 *
3061 	 * The problem is that write_cache_pages(), located in
3062 	 * mm/page-writeback.c, marks pages clean in preparation for
3063 	 * doing I/O, which is not desirable if we're not planning on
3064 	 * doing I/O at all.
3065 	 *
3066 	 * We could call write_cache_pages(), and then redirty all of
3067 	 * the pages by calling redirty_page_for_writepage() but that
3068 	 * would be ugly in the extreme.  So instead we would need to
3069 	 * replicate parts of the code in the above functions,
3070 	 * simplifying them because we wouldn't actually intend to
3071 	 * write out the pages, but rather only collect contiguous
3072 	 * logical block extents, call the multi-block allocator, and
3073 	 * then update the buffer heads with the block allocations.
3074 	 *
3075 	 * For now, though, we'll cheat by calling filemap_flush(),
3076 	 * which will map the blocks, and start the I/O, but not
3077 	 * actually wait for the I/O to complete.
3078 	 */
3079 	return filemap_flush(inode->i_mapping);
3080 }
3081 
3082 /*
3083  * bmap() is special.  It gets used by applications such as lilo and by
3084  * the swapper to find the on-disk block of a specific piece of data.
3085  *
3086  * Naturally, this is dangerous if the block concerned is still in the
3087  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3088  * filesystem and enables swap, then they may get a nasty shock when the
3089  * data getting swapped to that swapfile suddenly gets overwritten by
3090  * the original zero's written out previously to the journal and
3091  * awaiting writeback in the kernel's buffer cache.
3092  *
3093  * So, if we see any bmap calls here on a modified, data-journaled file,
3094  * take extra steps to flush any blocks which might be in the cache.
3095  */
ext4_bmap(struct address_space * mapping,sector_t block)3096 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3097 {
3098 	struct inode *inode = mapping->host;
3099 	sector_t ret = 0;
3100 
3101 	inode_lock_shared(inode);
3102 	/*
3103 	 * We can get here for an inline file via the FIBMAP ioctl
3104 	 */
3105 	if (ext4_has_inline_data(inode))
3106 		goto out;
3107 
3108 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3109 	    (test_opt(inode->i_sb, DELALLOC) ||
3110 	     ext4_should_journal_data(inode))) {
3111 		/*
3112 		 * With delalloc or journalled data we want to sync the file so
3113 		 * that we can make sure we allocate blocks for file and data
3114 		 * is in place for the user to see it
3115 		 */
3116 		filemap_write_and_wait(mapping);
3117 	}
3118 
3119 	ret = iomap_bmap(mapping, block, &ext4_iomap_ops);
3120 
3121 out:
3122 	inode_unlock_shared(inode);
3123 	return ret;
3124 }
3125 
ext4_read_folio(struct file * file,struct folio * folio)3126 static int ext4_read_folio(struct file *file, struct folio *folio)
3127 {
3128 	int ret = -EAGAIN;
3129 	struct inode *inode = folio->mapping->host;
3130 
3131 	trace_ext4_read_folio(inode, folio);
3132 
3133 	if (ext4_has_inline_data(inode))
3134 		ret = ext4_readpage_inline(inode, folio);
3135 
3136 	if (ret == -EAGAIN)
3137 		return ext4_mpage_readpages(inode, NULL, folio);
3138 
3139 	return ret;
3140 }
3141 
ext4_readahead(struct readahead_control * rac)3142 static void ext4_readahead(struct readahead_control *rac)
3143 {
3144 	struct inode *inode = rac->mapping->host;
3145 
3146 	/* If the file has inline data, no need to do readahead. */
3147 	if (ext4_has_inline_data(inode))
3148 		return;
3149 
3150 	ext4_mpage_readpages(inode, rac, NULL);
3151 }
3152 
ext4_invalidate_folio(struct folio * folio,size_t offset,size_t length)3153 static void ext4_invalidate_folio(struct folio *folio, size_t offset,
3154 				size_t length)
3155 {
3156 	trace_ext4_invalidate_folio(folio, offset, length);
3157 
3158 	/* No journalling happens on data buffers when this function is used */
3159 	WARN_ON(folio_buffers(folio) && buffer_jbd(folio_buffers(folio)));
3160 
3161 	block_invalidate_folio(folio, offset, length);
3162 }
3163 
__ext4_journalled_invalidate_folio(struct folio * folio,size_t offset,size_t length)3164 static int __ext4_journalled_invalidate_folio(struct folio *folio,
3165 					    size_t offset, size_t length)
3166 {
3167 	journal_t *journal = EXT4_JOURNAL(folio->mapping->host);
3168 
3169 	trace_ext4_journalled_invalidate_folio(folio, offset, length);
3170 
3171 	/*
3172 	 * If it's a full truncate we just forget about the pending dirtying
3173 	 */
3174 	if (offset == 0 && length == folio_size(folio))
3175 		folio_clear_checked(folio);
3176 
3177 	return jbd2_journal_invalidate_folio(journal, folio, offset, length);
3178 }
3179 
3180 /* Wrapper for aops... */
ext4_journalled_invalidate_folio(struct folio * folio,size_t offset,size_t length)3181 static void ext4_journalled_invalidate_folio(struct folio *folio,
3182 					   size_t offset,
3183 					   size_t length)
3184 {
3185 	WARN_ON(__ext4_journalled_invalidate_folio(folio, offset, length) < 0);
3186 }
3187 
ext4_release_folio(struct folio * folio,gfp_t wait)3188 static bool ext4_release_folio(struct folio *folio, gfp_t wait)
3189 {
3190 	struct inode *inode = folio->mapping->host;
3191 	journal_t *journal = EXT4_JOURNAL(inode);
3192 
3193 	trace_ext4_release_folio(inode, folio);
3194 
3195 	/* Page has dirty journalled data -> cannot release */
3196 	if (folio_test_checked(folio))
3197 		return false;
3198 	if (journal)
3199 		return jbd2_journal_try_to_free_buffers(journal, folio);
3200 	else
3201 		return try_to_free_buffers(folio);
3202 }
3203 
ext4_inode_datasync_dirty(struct inode * inode)3204 static bool ext4_inode_datasync_dirty(struct inode *inode)
3205 {
3206 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
3207 
3208 	if (journal) {
3209 		if (jbd2_transaction_committed(journal,
3210 			EXT4_I(inode)->i_datasync_tid))
3211 			return false;
3212 		if (test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT))
3213 			return !list_empty(&EXT4_I(inode)->i_fc_list);
3214 		return true;
3215 	}
3216 
3217 	/* Any metadata buffers to write? */
3218 	if (!list_empty(&inode->i_mapping->private_list))
3219 		return true;
3220 	return inode->i_state & I_DIRTY_DATASYNC;
3221 }
3222 
ext4_set_iomap(struct inode * inode,struct iomap * iomap,struct ext4_map_blocks * map,loff_t offset,loff_t length,unsigned int flags)3223 static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
3224 			   struct ext4_map_blocks *map, loff_t offset,
3225 			   loff_t length, unsigned int flags)
3226 {
3227 	u8 blkbits = inode->i_blkbits;
3228 
3229 	/*
3230 	 * Writes that span EOF might trigger an I/O size update on completion,
3231 	 * so consider them to be dirty for the purpose of O_DSYNC, even if
3232 	 * there is no other metadata changes being made or are pending.
3233 	 */
3234 	iomap->flags = 0;
3235 	if (ext4_inode_datasync_dirty(inode) ||
3236 	    offset + length > i_size_read(inode))
3237 		iomap->flags |= IOMAP_F_DIRTY;
3238 
3239 	if (map->m_flags & EXT4_MAP_NEW)
3240 		iomap->flags |= IOMAP_F_NEW;
3241 
3242 	if (flags & IOMAP_DAX)
3243 		iomap->dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
3244 	else
3245 		iomap->bdev = inode->i_sb->s_bdev;
3246 	iomap->offset = (u64) map->m_lblk << blkbits;
3247 	iomap->length = (u64) map->m_len << blkbits;
3248 
3249 	if ((map->m_flags & EXT4_MAP_MAPPED) &&
3250 	    !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3251 		iomap->flags |= IOMAP_F_MERGED;
3252 
3253 	/*
3254 	 * Flags passed to ext4_map_blocks() for direct I/O writes can result
3255 	 * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits
3256 	 * set. In order for any allocated unwritten extents to be converted
3257 	 * into written extents correctly within the ->end_io() handler, we
3258 	 * need to ensure that the iomap->type is set appropriately. Hence, the
3259 	 * reason why we need to check whether the EXT4_MAP_UNWRITTEN bit has
3260 	 * been set first.
3261 	 */
3262 	if (map->m_flags & EXT4_MAP_UNWRITTEN) {
3263 		iomap->type = IOMAP_UNWRITTEN;
3264 		iomap->addr = (u64) map->m_pblk << blkbits;
3265 		if (flags & IOMAP_DAX)
3266 			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
3267 	} else if (map->m_flags & EXT4_MAP_MAPPED) {
3268 		iomap->type = IOMAP_MAPPED;
3269 		iomap->addr = (u64) map->m_pblk << blkbits;
3270 		if (flags & IOMAP_DAX)
3271 			iomap->addr += EXT4_SB(inode->i_sb)->s_dax_part_off;
3272 	} else {
3273 		iomap->type = IOMAP_HOLE;
3274 		iomap->addr = IOMAP_NULL_ADDR;
3275 	}
3276 }
3277 
ext4_iomap_alloc(struct inode * inode,struct ext4_map_blocks * map,unsigned int flags)3278 static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
3279 			    unsigned int flags)
3280 {
3281 	handle_t *handle;
3282 	u8 blkbits = inode->i_blkbits;
3283 	int ret, dio_credits, m_flags = 0, retries = 0;
3284 
3285 	/*
3286 	 * Trim the mapping request to the maximum value that we can map at
3287 	 * once for direct I/O.
3288 	 */
3289 	if (map->m_len > DIO_MAX_BLOCKS)
3290 		map->m_len = DIO_MAX_BLOCKS;
3291 	dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
3292 
3293 retry:
3294 	/*
3295 	 * Either we allocate blocks and then don't get an unwritten extent, so
3296 	 * in that case we have reserved enough credits. Or, the blocks are
3297 	 * already allocated and unwritten. In that case, the extent conversion
3298 	 * fits into the credits as well.
3299 	 */
3300 	handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
3301 	if (IS_ERR(handle))
3302 		return PTR_ERR(handle);
3303 
3304 	/*
3305 	 * DAX and direct I/O are the only two operations that are currently
3306 	 * supported with IOMAP_WRITE.
3307 	 */
3308 	WARN_ON(!(flags & (IOMAP_DAX | IOMAP_DIRECT)));
3309 	if (flags & IOMAP_DAX)
3310 		m_flags = EXT4_GET_BLOCKS_CREATE_ZERO;
3311 	/*
3312 	 * We use i_size instead of i_disksize here because delalloc writeback
3313 	 * can complete at any point during the I/O and subsequently push the
3314 	 * i_disksize out to i_size. This could be beyond where direct I/O is
3315 	 * happening and thus expose allocated blocks to direct I/O reads.
3316 	 */
3317 	else if (((loff_t)map->m_lblk << blkbits) >= i_size_read(inode))
3318 		m_flags = EXT4_GET_BLOCKS_CREATE;
3319 	else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3320 		m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT;
3321 
3322 	ret = ext4_map_blocks(handle, inode, map, m_flags);
3323 
3324 	/*
3325 	 * We cannot fill holes in indirect tree based inodes as that could
3326 	 * expose stale data in the case of a crash. Use the magic error code
3327 	 * to fallback to buffered I/O.
3328 	 */
3329 	if (!m_flags && !ret)
3330 		ret = -ENOTBLK;
3331 
3332 	ext4_journal_stop(handle);
3333 	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3334 		goto retry;
3335 
3336 	return ret;
3337 }
3338 
3339 
ext4_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)3340 static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
3341 		unsigned flags, struct iomap *iomap, struct iomap *srcmap)
3342 {
3343 	int ret;
3344 	struct ext4_map_blocks map;
3345 	u8 blkbits = inode->i_blkbits;
3346 
3347 	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3348 		return -EINVAL;
3349 
3350 	if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
3351 		return -ERANGE;
3352 
3353 	/*
3354 	 * Calculate the first and last logical blocks respectively.
3355 	 */
3356 	map.m_lblk = offset >> blkbits;
3357 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3358 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3359 
3360 	if (flags & IOMAP_WRITE) {
3361 		/*
3362 		 * We check here if the blocks are already allocated, then we
3363 		 * don't need to start a journal txn and we can directly return
3364 		 * the mapping information. This could boost performance
3365 		 * especially in multi-threaded overwrite requests.
3366 		 */
3367 		if (offset + length <= i_size_read(inode)) {
3368 			ret = ext4_map_blocks(NULL, inode, &map, 0);
3369 			if (ret > 0 && (map.m_flags & EXT4_MAP_MAPPED))
3370 				goto out;
3371 		}
3372 		ret = ext4_iomap_alloc(inode, &map, flags);
3373 	} else {
3374 		ret = ext4_map_blocks(NULL, inode, &map, 0);
3375 	}
3376 
3377 	if (ret < 0)
3378 		return ret;
3379 out:
3380 	/*
3381 	 * When inline encryption is enabled, sometimes I/O to an encrypted file
3382 	 * has to be broken up to guarantee DUN contiguity.  Handle this by
3383 	 * limiting the length of the mapping returned.
3384 	 */
3385 	map.m_len = fscrypt_limit_io_blocks(inode, map.m_lblk, map.m_len);
3386 
3387 	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
3388 
3389 	return 0;
3390 }
3391 
ext4_iomap_overwrite_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)3392 static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset,
3393 		loff_t length, unsigned flags, struct iomap *iomap,
3394 		struct iomap *srcmap)
3395 {
3396 	int ret;
3397 
3398 	/*
3399 	 * Even for writes we don't need to allocate blocks, so just pretend
3400 	 * we are reading to save overhead of starting a transaction.
3401 	 */
3402 	flags &= ~IOMAP_WRITE;
3403 	ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap);
3404 	WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED);
3405 	return ret;
3406 }
3407 
ext4_iomap_end(struct inode * inode,loff_t offset,loff_t length,ssize_t written,unsigned flags,struct iomap * iomap)3408 static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
3409 			  ssize_t written, unsigned flags, struct iomap *iomap)
3410 {
3411 	/*
3412 	 * Check to see whether an error occurred while writing out the data to
3413 	 * the allocated blocks. If so, return the magic error code so that we
3414 	 * fallback to buffered I/O and attempt to complete the remainder of
3415 	 * the I/O. Any blocks that may have been allocated in preparation for
3416 	 * the direct I/O will be reused during buffered I/O.
3417 	 */
3418 	if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0)
3419 		return -ENOTBLK;
3420 
3421 	return 0;
3422 }
3423 
3424 const struct iomap_ops ext4_iomap_ops = {
3425 	.iomap_begin		= ext4_iomap_begin,
3426 	.iomap_end		= ext4_iomap_end,
3427 };
3428 
3429 const struct iomap_ops ext4_iomap_overwrite_ops = {
3430 	.iomap_begin		= ext4_iomap_overwrite_begin,
3431 	.iomap_end		= ext4_iomap_end,
3432 };
3433 
ext4_iomap_is_delalloc(struct inode * inode,struct ext4_map_blocks * map)3434 static bool ext4_iomap_is_delalloc(struct inode *inode,
3435 				   struct ext4_map_blocks *map)
3436 {
3437 	struct extent_status es;
3438 	ext4_lblk_t offset = 0, end = map->m_lblk + map->m_len - 1;
3439 
3440 	ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
3441 				  map->m_lblk, end, &es);
3442 
3443 	if (!es.es_len || es.es_lblk > end)
3444 		return false;
3445 
3446 	if (es.es_lblk > map->m_lblk) {
3447 		map->m_len = es.es_lblk - map->m_lblk;
3448 		return false;
3449 	}
3450 
3451 	offset = map->m_lblk - es.es_lblk;
3452 	map->m_len = es.es_len - offset;
3453 
3454 	return true;
3455 }
3456 
ext4_iomap_begin_report(struct inode * inode,loff_t offset,loff_t length,unsigned int flags,struct iomap * iomap,struct iomap * srcmap)3457 static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
3458 				   loff_t length, unsigned int flags,
3459 				   struct iomap *iomap, struct iomap *srcmap)
3460 {
3461 	int ret;
3462 	bool delalloc = false;
3463 	struct ext4_map_blocks map;
3464 	u8 blkbits = inode->i_blkbits;
3465 
3466 	if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
3467 		return -EINVAL;
3468 
3469 	if (ext4_has_inline_data(inode)) {
3470 		ret = ext4_inline_data_iomap(inode, iomap);
3471 		if (ret != -EAGAIN) {
3472 			if (ret == 0 && offset >= iomap->length)
3473 				ret = -ENOENT;
3474 			return ret;
3475 		}
3476 	}
3477 
3478 	/*
3479 	 * Calculate the first and last logical block respectively.
3480 	 */
3481 	map.m_lblk = offset >> blkbits;
3482 	map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits,
3483 			  EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1;
3484 
3485 	/*
3486 	 * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
3487 	 * So handle it here itself instead of querying ext4_map_blocks().
3488 	 * Since ext4_map_blocks() will warn about it and will return
3489 	 * -EIO error.
3490 	 */
3491 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
3492 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3493 
3494 		if (offset >= sbi->s_bitmap_maxbytes) {
3495 			map.m_flags = 0;
3496 			goto set_iomap;
3497 		}
3498 	}
3499 
3500 	ret = ext4_map_blocks(NULL, inode, &map, 0);
3501 	if (ret < 0)
3502 		return ret;
3503 	if (ret == 0)
3504 		delalloc = ext4_iomap_is_delalloc(inode, &map);
3505 
3506 set_iomap:
3507 	ext4_set_iomap(inode, iomap, &map, offset, length, flags);
3508 	if (delalloc && iomap->type == IOMAP_HOLE)
3509 		iomap->type = IOMAP_DELALLOC;
3510 
3511 	return 0;
3512 }
3513 
3514 const struct iomap_ops ext4_iomap_report_ops = {
3515 	.iomap_begin = ext4_iomap_begin_report,
3516 };
3517 
3518 /*
3519  * For data=journal mode, folio should be marked dirty only when it was
3520  * writeably mapped. When that happens, it was already attached to the
3521  * transaction and marked as jbddirty (we take care of this in
3522  * ext4_page_mkwrite()). On transaction commit, we writeprotect page mappings
3523  * so we should have nothing to do here, except for the case when someone
3524  * had the page pinned and dirtied the page through this pin (e.g. by doing
3525  * direct IO to it). In that case we'd need to attach buffers here to the
3526  * transaction but we cannot due to lock ordering.  We cannot just dirty the
3527  * folio and leave attached buffers clean, because the buffers' dirty state is
3528  * "definitive".  We cannot just set the buffers dirty or jbddirty because all
3529  * the journalling code will explode.  So what we do is to mark the folio
3530  * "pending dirty" and next time ext4_writepages() is called, attach buffers
3531  * to the transaction appropriately.
3532  */
ext4_journalled_dirty_folio(struct address_space * mapping,struct folio * folio)3533 static bool ext4_journalled_dirty_folio(struct address_space *mapping,
3534 		struct folio *folio)
3535 {
3536 	WARN_ON_ONCE(!folio_buffers(folio));
3537 	if (folio_maybe_dma_pinned(folio))
3538 		folio_set_checked(folio);
3539 	return filemap_dirty_folio(mapping, folio);
3540 }
3541 
ext4_dirty_folio(struct address_space * mapping,struct folio * folio)3542 static bool ext4_dirty_folio(struct address_space *mapping, struct folio *folio)
3543 {
3544 	WARN_ON_ONCE(!folio_test_locked(folio) && !folio_test_dirty(folio));
3545 	WARN_ON_ONCE(!folio_buffers(folio));
3546 	return block_dirty_folio(mapping, folio);
3547 }
3548 
ext4_iomap_swap_activate(struct swap_info_struct * sis,struct file * file,sector_t * span)3549 static int ext4_iomap_swap_activate(struct swap_info_struct *sis,
3550 				    struct file *file, sector_t *span)
3551 {
3552 	return iomap_swapfile_activate(sis, file, span,
3553 				       &ext4_iomap_report_ops);
3554 }
3555 
3556 static const struct address_space_operations ext4_aops = {
3557 	.read_folio		= ext4_read_folio,
3558 	.readahead		= ext4_readahead,
3559 	.writepages		= ext4_writepages,
3560 	.write_begin		= ext4_write_begin,
3561 	.write_end		= ext4_write_end,
3562 	.dirty_folio		= ext4_dirty_folio,
3563 	.bmap			= ext4_bmap,
3564 	.invalidate_folio	= ext4_invalidate_folio,
3565 	.release_folio		= ext4_release_folio,
3566 	.direct_IO		= noop_direct_IO,
3567 	.migrate_folio		= buffer_migrate_folio,
3568 	.is_partially_uptodate  = block_is_partially_uptodate,
3569 	.error_remove_page	= generic_error_remove_page,
3570 	.swap_activate		= ext4_iomap_swap_activate,
3571 };
3572 
3573 static const struct address_space_operations ext4_journalled_aops = {
3574 	.read_folio		= ext4_read_folio,
3575 	.readahead		= ext4_readahead,
3576 	.writepages		= ext4_writepages,
3577 	.write_begin		= ext4_write_begin,
3578 	.write_end		= ext4_journalled_write_end,
3579 	.dirty_folio		= ext4_journalled_dirty_folio,
3580 	.bmap			= ext4_bmap,
3581 	.invalidate_folio	= ext4_journalled_invalidate_folio,
3582 	.release_folio		= ext4_release_folio,
3583 	.direct_IO		= noop_direct_IO,
3584 	.migrate_folio		= buffer_migrate_folio_norefs,
3585 	.is_partially_uptodate  = block_is_partially_uptodate,
3586 	.error_remove_page	= generic_error_remove_page,
3587 	.swap_activate		= ext4_iomap_swap_activate,
3588 };
3589 
3590 static const struct address_space_operations ext4_da_aops = {
3591 	.read_folio		= ext4_read_folio,
3592 	.readahead		= ext4_readahead,
3593 	.writepages		= ext4_writepages,
3594 	.write_begin		= ext4_da_write_begin,
3595 	.write_end		= ext4_da_write_end,
3596 	.dirty_folio		= ext4_dirty_folio,
3597 	.bmap			= ext4_bmap,
3598 	.invalidate_folio	= ext4_invalidate_folio,
3599 	.release_folio		= ext4_release_folio,
3600 	.direct_IO		= noop_direct_IO,
3601 	.migrate_folio		= buffer_migrate_folio,
3602 	.is_partially_uptodate  = block_is_partially_uptodate,
3603 	.error_remove_page	= generic_error_remove_page,
3604 	.swap_activate		= ext4_iomap_swap_activate,
3605 };
3606 
3607 static const struct address_space_operations ext4_dax_aops = {
3608 	.writepages		= ext4_dax_writepages,
3609 	.direct_IO		= noop_direct_IO,
3610 	.dirty_folio		= noop_dirty_folio,
3611 	.bmap			= ext4_bmap,
3612 	.swap_activate		= ext4_iomap_swap_activate,
3613 };
3614 
ext4_set_aops(struct inode * inode)3615 void ext4_set_aops(struct inode *inode)
3616 {
3617 	switch (ext4_inode_journal_mode(inode)) {
3618 	case EXT4_INODE_ORDERED_DATA_MODE:
3619 	case EXT4_INODE_WRITEBACK_DATA_MODE:
3620 		break;
3621 	case EXT4_INODE_JOURNAL_DATA_MODE:
3622 		inode->i_mapping->a_ops = &ext4_journalled_aops;
3623 		return;
3624 	default:
3625 		BUG();
3626 	}
3627 	if (IS_DAX(inode))
3628 		inode->i_mapping->a_ops = &ext4_dax_aops;
3629 	else if (test_opt(inode->i_sb, DELALLOC))
3630 		inode->i_mapping->a_ops = &ext4_da_aops;
3631 	else
3632 		inode->i_mapping->a_ops = &ext4_aops;
3633 }
3634 
__ext4_block_zero_page_range(handle_t * handle,struct address_space * mapping,loff_t from,loff_t length)3635 static int __ext4_block_zero_page_range(handle_t *handle,
3636 		struct address_space *mapping, loff_t from, loff_t length)
3637 {
3638 	ext4_fsblk_t index = from >> PAGE_SHIFT;
3639 	unsigned offset = from & (PAGE_SIZE-1);
3640 	unsigned blocksize, pos;
3641 	ext4_lblk_t iblock;
3642 	struct inode *inode = mapping->host;
3643 	struct buffer_head *bh;
3644 	struct folio *folio;
3645 	int err = 0;
3646 
3647 	folio = __filemap_get_folio(mapping, from >> PAGE_SHIFT,
3648 				    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
3649 				    mapping_gfp_constraint(mapping, ~__GFP_FS));
3650 	if (IS_ERR(folio))
3651 		return PTR_ERR(folio);
3652 
3653 	blocksize = inode->i_sb->s_blocksize;
3654 
3655 	iblock = index << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
3656 
3657 	bh = folio_buffers(folio);
3658 	if (!bh) {
3659 		create_empty_buffers(&folio->page, blocksize, 0);
3660 		bh = folio_buffers(folio);
3661 	}
3662 
3663 	/* Find the buffer that contains "offset" */
3664 	pos = blocksize;
3665 	while (offset >= pos) {
3666 		bh = bh->b_this_page;
3667 		iblock++;
3668 		pos += blocksize;
3669 	}
3670 	if (buffer_freed(bh)) {
3671 		BUFFER_TRACE(bh, "freed: skip");
3672 		goto unlock;
3673 	}
3674 	if (!buffer_mapped(bh)) {
3675 		BUFFER_TRACE(bh, "unmapped");
3676 		ext4_get_block(inode, iblock, bh, 0);
3677 		/* unmapped? It's a hole - nothing to do */
3678 		if (!buffer_mapped(bh)) {
3679 			BUFFER_TRACE(bh, "still unmapped");
3680 			goto unlock;
3681 		}
3682 	}
3683 
3684 	/* Ok, it's mapped. Make sure it's up-to-date */
3685 	if (folio_test_uptodate(folio))
3686 		set_buffer_uptodate(bh);
3687 
3688 	if (!buffer_uptodate(bh)) {
3689 		err = ext4_read_bh_lock(bh, 0, true);
3690 		if (err)
3691 			goto unlock;
3692 		if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
3693 			/* We expect the key to be set. */
3694 			BUG_ON(!fscrypt_has_encryption_key(inode));
3695 			err = fscrypt_decrypt_pagecache_blocks(folio,
3696 							       blocksize,
3697 							       bh_offset(bh));
3698 			if (err) {
3699 				clear_buffer_uptodate(bh);
3700 				goto unlock;
3701 			}
3702 		}
3703 	}
3704 	if (ext4_should_journal_data(inode)) {
3705 		BUFFER_TRACE(bh, "get write access");
3706 		err = ext4_journal_get_write_access(handle, inode->i_sb, bh,
3707 						    EXT4_JTR_NONE);
3708 		if (err)
3709 			goto unlock;
3710 	}
3711 	folio_zero_range(folio, offset, length);
3712 	BUFFER_TRACE(bh, "zeroed end of block");
3713 
3714 	if (ext4_should_journal_data(inode)) {
3715 		err = ext4_dirty_journalled_data(handle, bh);
3716 	} else {
3717 		err = 0;
3718 		mark_buffer_dirty(bh);
3719 		if (ext4_should_order_data(inode))
3720 			err = ext4_jbd2_inode_add_write(handle, inode, from,
3721 					length);
3722 	}
3723 
3724 unlock:
3725 	folio_unlock(folio);
3726 	folio_put(folio);
3727 	return err;
3728 }
3729 
3730 /*
3731  * ext4_block_zero_page_range() zeros out a mapping of length 'length'
3732  * starting from file offset 'from'.  The range to be zero'd must
3733  * be contained with in one block.  If the specified range exceeds
3734  * the end of the block it will be shortened to end of the block
3735  * that corresponds to 'from'
3736  */
ext4_block_zero_page_range(handle_t * handle,struct address_space * mapping,loff_t from,loff_t length)3737 static int ext4_block_zero_page_range(handle_t *handle,
3738 		struct address_space *mapping, loff_t from, loff_t length)
3739 {
3740 	struct inode *inode = mapping->host;
3741 	unsigned offset = from & (PAGE_SIZE-1);
3742 	unsigned blocksize = inode->i_sb->s_blocksize;
3743 	unsigned max = blocksize - (offset & (blocksize - 1));
3744 
3745 	/*
3746 	 * correct length if it does not fall between
3747 	 * 'from' and the end of the block
3748 	 */
3749 	if (length > max || length < 0)
3750 		length = max;
3751 
3752 	if (IS_DAX(inode)) {
3753 		return dax_zero_range(inode, from, length, NULL,
3754 				      &ext4_iomap_ops);
3755 	}
3756 	return __ext4_block_zero_page_range(handle, mapping, from, length);
3757 }
3758 
3759 /*
3760  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3761  * up to the end of the block which corresponds to `from'.
3762  * This required during truncate. We need to physically zero the tail end
3763  * of that block so it doesn't yield old data if the file is later grown.
3764  */
ext4_block_truncate_page(handle_t * handle,struct address_space * mapping,loff_t from)3765 static int ext4_block_truncate_page(handle_t *handle,
3766 		struct address_space *mapping, loff_t from)
3767 {
3768 	unsigned offset = from & (PAGE_SIZE-1);
3769 	unsigned length;
3770 	unsigned blocksize;
3771 	struct inode *inode = mapping->host;
3772 
3773 	/* If we are processing an encrypted inode during orphan list handling */
3774 	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
3775 		return 0;
3776 
3777 	blocksize = inode->i_sb->s_blocksize;
3778 	length = blocksize - (offset & (blocksize - 1));
3779 
3780 	return ext4_block_zero_page_range(handle, mapping, from, length);
3781 }
3782 
ext4_zero_partial_blocks(handle_t * handle,struct inode * inode,loff_t lstart,loff_t length)3783 int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
3784 			     loff_t lstart, loff_t length)
3785 {
3786 	struct super_block *sb = inode->i_sb;
3787 	struct address_space *mapping = inode->i_mapping;
3788 	unsigned partial_start, partial_end;
3789 	ext4_fsblk_t start, end;
3790 	loff_t byte_end = (lstart + length - 1);
3791 	int err = 0;
3792 
3793 	partial_start = lstart & (sb->s_blocksize - 1);
3794 	partial_end = byte_end & (sb->s_blocksize - 1);
3795 
3796 	start = lstart >> sb->s_blocksize_bits;
3797 	end = byte_end >> sb->s_blocksize_bits;
3798 
3799 	/* Handle partial zero within the single block */
3800 	if (start == end &&
3801 	    (partial_start || (partial_end != sb->s_blocksize - 1))) {
3802 		err = ext4_block_zero_page_range(handle, mapping,
3803 						 lstart, length);
3804 		return err;
3805 	}
3806 	/* Handle partial zero out on the start of the range */
3807 	if (partial_start) {
3808 		err = ext4_block_zero_page_range(handle, mapping,
3809 						 lstart, sb->s_blocksize);
3810 		if (err)
3811 			return err;
3812 	}
3813 	/* Handle partial zero out on the end of the range */
3814 	if (partial_end != sb->s_blocksize - 1)
3815 		err = ext4_block_zero_page_range(handle, mapping,
3816 						 byte_end - partial_end,
3817 						 partial_end + 1);
3818 	return err;
3819 }
3820 
ext4_can_truncate(struct inode * inode)3821 int ext4_can_truncate(struct inode *inode)
3822 {
3823 	if (S_ISREG(inode->i_mode))
3824 		return 1;
3825 	if (S_ISDIR(inode->i_mode))
3826 		return 1;
3827 	if (S_ISLNK(inode->i_mode))
3828 		return !ext4_inode_is_fast_symlink(inode);
3829 	return 0;
3830 }
3831 
3832 /*
3833  * We have to make sure i_disksize gets properly updated before we truncate
3834  * page cache due to hole punching or zero range. Otherwise i_disksize update
3835  * can get lost as it may have been postponed to submission of writeback but
3836  * that will never happen after we truncate page cache.
3837  */
ext4_update_disksize_before_punch(struct inode * inode,loff_t offset,loff_t len)3838 int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
3839 				      loff_t len)
3840 {
3841 	handle_t *handle;
3842 	int ret;
3843 
3844 	loff_t size = i_size_read(inode);
3845 
3846 	WARN_ON(!inode_is_locked(inode));
3847 	if (offset > size || offset + len < size)
3848 		return 0;
3849 
3850 	if (EXT4_I(inode)->i_disksize >= size)
3851 		return 0;
3852 
3853 	handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
3854 	if (IS_ERR(handle))
3855 		return PTR_ERR(handle);
3856 	ext4_update_i_disksize(inode, size);
3857 	ret = ext4_mark_inode_dirty(handle, inode);
3858 	ext4_journal_stop(handle);
3859 
3860 	return ret;
3861 }
3862 
ext4_wait_dax_page(struct inode * inode)3863 static void ext4_wait_dax_page(struct inode *inode)
3864 {
3865 	filemap_invalidate_unlock(inode->i_mapping);
3866 	schedule();
3867 	filemap_invalidate_lock(inode->i_mapping);
3868 }
3869 
ext4_break_layouts(struct inode * inode)3870 int ext4_break_layouts(struct inode *inode)
3871 {
3872 	struct page *page;
3873 	int error;
3874 
3875 	if (WARN_ON_ONCE(!rwsem_is_locked(&inode->i_mapping->invalidate_lock)))
3876 		return -EINVAL;
3877 
3878 	do {
3879 		page = dax_layout_busy_page(inode->i_mapping);
3880 		if (!page)
3881 			return 0;
3882 
3883 		error = ___wait_var_event(&page->_refcount,
3884 				atomic_read(&page->_refcount) == 1,
3885 				TASK_INTERRUPTIBLE, 0, 0,
3886 				ext4_wait_dax_page(inode));
3887 	} while (error == 0);
3888 
3889 	return error;
3890 }
3891 
3892 /*
3893  * ext4_punch_hole: punches a hole in a file by releasing the blocks
3894  * associated with the given offset and length
3895  *
3896  * @inode:  File inode
3897  * @offset: The offset where the hole will begin
3898  * @len:    The length of the hole
3899  *
3900  * Returns: 0 on success or negative on failure
3901  */
3902 
ext4_punch_hole(struct file * file,loff_t offset,loff_t length)3903 int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
3904 {
3905 	struct inode *inode = file_inode(file);
3906 	struct super_block *sb = inode->i_sb;
3907 	ext4_lblk_t first_block, stop_block;
3908 	struct address_space *mapping = inode->i_mapping;
3909 	loff_t first_block_offset, last_block_offset, max_length;
3910 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3911 	handle_t *handle;
3912 	unsigned int credits;
3913 	int ret = 0, ret2 = 0;
3914 
3915 	trace_ext4_punch_hole(inode, offset, length, 0);
3916 
3917 	/*
3918 	 * Write out all dirty pages to avoid race conditions
3919 	 * Then release them.
3920 	 */
3921 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
3922 		ret = filemap_write_and_wait_range(mapping, offset,
3923 						   offset + length - 1);
3924 		if (ret)
3925 			return ret;
3926 	}
3927 
3928 	inode_lock(inode);
3929 
3930 	/* No need to punch hole beyond i_size */
3931 	if (offset >= inode->i_size)
3932 		goto out_mutex;
3933 
3934 	/*
3935 	 * If the hole extends beyond i_size, set the hole
3936 	 * to end after the page that contains i_size
3937 	 */
3938 	if (offset + length > inode->i_size) {
3939 		length = inode->i_size +
3940 		   PAGE_SIZE - (inode->i_size & (PAGE_SIZE - 1)) -
3941 		   offset;
3942 	}
3943 
3944 	/*
3945 	 * For punch hole the length + offset needs to be within one block
3946 	 * before last range. Adjust the length if it goes beyond that limit.
3947 	 */
3948 	max_length = sbi->s_bitmap_maxbytes - inode->i_sb->s_blocksize;
3949 	if (offset + length > max_length)
3950 		length = max_length - offset;
3951 
3952 	if (offset & (sb->s_blocksize - 1) ||
3953 	    (offset + length) & (sb->s_blocksize - 1)) {
3954 		/*
3955 		 * Attach jinode to inode for jbd2 if we do any zeroing of
3956 		 * partial block
3957 		 */
3958 		ret = ext4_inode_attach_jinode(inode);
3959 		if (ret < 0)
3960 			goto out_mutex;
3961 
3962 	}
3963 
3964 	/* Wait all existing dio workers, newcomers will block on i_rwsem */
3965 	inode_dio_wait(inode);
3966 
3967 	ret = file_modified(file);
3968 	if (ret)
3969 		goto out_mutex;
3970 
3971 	/*
3972 	 * Prevent page faults from reinstantiating pages we have released from
3973 	 * page cache.
3974 	 */
3975 	filemap_invalidate_lock(mapping);
3976 
3977 	ret = ext4_break_layouts(inode);
3978 	if (ret)
3979 		goto out_dio;
3980 
3981 	first_block_offset = round_up(offset, sb->s_blocksize);
3982 	last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
3983 
3984 	/* Now release the pages and zero block aligned part of pages*/
3985 	if (last_block_offset > first_block_offset) {
3986 		ret = ext4_update_disksize_before_punch(inode, offset, length);
3987 		if (ret)
3988 			goto out_dio;
3989 		truncate_pagecache_range(inode, first_block_offset,
3990 					 last_block_offset);
3991 	}
3992 
3993 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
3994 		credits = ext4_writepage_trans_blocks(inode);
3995 	else
3996 		credits = ext4_blocks_for_truncate(inode);
3997 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
3998 	if (IS_ERR(handle)) {
3999 		ret = PTR_ERR(handle);
4000 		ext4_std_error(sb, ret);
4001 		goto out_dio;
4002 	}
4003 
4004 	ret = ext4_zero_partial_blocks(handle, inode, offset,
4005 				       length);
4006 	if (ret)
4007 		goto out_stop;
4008 
4009 	first_block = (offset + sb->s_blocksize - 1) >>
4010 		EXT4_BLOCK_SIZE_BITS(sb);
4011 	stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
4012 
4013 	/* If there are blocks to remove, do it */
4014 	if (stop_block > first_block) {
4015 
4016 		down_write(&EXT4_I(inode)->i_data_sem);
4017 		ext4_discard_preallocations(inode, 0);
4018 
4019 		ext4_es_remove_extent(inode, first_block,
4020 				      stop_block - first_block);
4021 
4022 		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4023 			ret = ext4_ext_remove_space(inode, first_block,
4024 						    stop_block - 1);
4025 		else
4026 			ret = ext4_ind_remove_space(handle, inode, first_block,
4027 						    stop_block);
4028 
4029 		up_write(&EXT4_I(inode)->i_data_sem);
4030 	}
4031 	ext4_fc_track_range(handle, inode, first_block, stop_block);
4032 	if (IS_SYNC(inode))
4033 		ext4_handle_sync(handle);
4034 
4035 	inode->i_mtime = inode_set_ctime_current(inode);
4036 	ret2 = ext4_mark_inode_dirty(handle, inode);
4037 	if (unlikely(ret2))
4038 		ret = ret2;
4039 	if (ret >= 0)
4040 		ext4_update_inode_fsync_trans(handle, inode, 1);
4041 out_stop:
4042 	ext4_journal_stop(handle);
4043 out_dio:
4044 	filemap_invalidate_unlock(mapping);
4045 out_mutex:
4046 	inode_unlock(inode);
4047 	return ret;
4048 }
4049 
ext4_inode_attach_jinode(struct inode * inode)4050 int ext4_inode_attach_jinode(struct inode *inode)
4051 {
4052 	struct ext4_inode_info *ei = EXT4_I(inode);
4053 	struct jbd2_inode *jinode;
4054 
4055 	if (ei->jinode || !EXT4_SB(inode->i_sb)->s_journal)
4056 		return 0;
4057 
4058 	jinode = jbd2_alloc_inode(GFP_KERNEL);
4059 	spin_lock(&inode->i_lock);
4060 	if (!ei->jinode) {
4061 		if (!jinode) {
4062 			spin_unlock(&inode->i_lock);
4063 			return -ENOMEM;
4064 		}
4065 		ei->jinode = jinode;
4066 		jbd2_journal_init_jbd_inode(ei->jinode, inode);
4067 		jinode = NULL;
4068 	}
4069 	spin_unlock(&inode->i_lock);
4070 	if (unlikely(jinode != NULL))
4071 		jbd2_free_inode(jinode);
4072 	return 0;
4073 }
4074 
4075 /*
4076  * ext4_truncate()
4077  *
4078  * We block out ext4_get_block() block instantiations across the entire
4079  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4080  * simultaneously on behalf of the same inode.
4081  *
4082  * As we work through the truncate and commit bits of it to the journal there
4083  * is one core, guiding principle: the file's tree must always be consistent on
4084  * disk.  We must be able to restart the truncate after a crash.
4085  *
4086  * The file's tree may be transiently inconsistent in memory (although it
4087  * probably isn't), but whenever we close off and commit a journal transaction,
4088  * the contents of (the filesystem + the journal) must be consistent and
4089  * restartable.  It's pretty simple, really: bottom up, right to left (although
4090  * left-to-right works OK too).
4091  *
4092  * Note that at recovery time, journal replay occurs *before* the restart of
4093  * truncate against the orphan inode list.
4094  *
4095  * The committed inode has the new, desired i_size (which is the same as
4096  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4097  * that this inode's truncate did not complete and it will again call
4098  * ext4_truncate() to have another go.  So there will be instantiated blocks
4099  * to the right of the truncation point in a crashed ext4 filesystem.  But
4100  * that's fine - as long as they are linked from the inode, the post-crash
4101  * ext4_truncate() run will find them and release them.
4102  */
ext4_truncate(struct inode * inode)4103 int ext4_truncate(struct inode *inode)
4104 {
4105 	struct ext4_inode_info *ei = EXT4_I(inode);
4106 	unsigned int credits;
4107 	int err = 0, err2;
4108 	handle_t *handle;
4109 	struct address_space *mapping = inode->i_mapping;
4110 
4111 	/*
4112 	 * There is a possibility that we're either freeing the inode
4113 	 * or it's a completely new inode. In those cases we might not
4114 	 * have i_rwsem locked because it's not necessary.
4115 	 */
4116 	if (!(inode->i_state & (I_NEW|I_FREEING)))
4117 		WARN_ON(!inode_is_locked(inode));
4118 	trace_ext4_truncate_enter(inode);
4119 
4120 	if (!ext4_can_truncate(inode))
4121 		goto out_trace;
4122 
4123 	if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4124 		ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
4125 
4126 	if (ext4_has_inline_data(inode)) {
4127 		int has_inline = 1;
4128 
4129 		err = ext4_inline_data_truncate(inode, &has_inline);
4130 		if (err || has_inline)
4131 			goto out_trace;
4132 	}
4133 
4134 	/* If we zero-out tail of the page, we have to create jinode for jbd2 */
4135 	if (inode->i_size & (inode->i_sb->s_blocksize - 1)) {
4136 		err = ext4_inode_attach_jinode(inode);
4137 		if (err)
4138 			goto out_trace;
4139 	}
4140 
4141 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4142 		credits = ext4_writepage_trans_blocks(inode);
4143 	else
4144 		credits = ext4_blocks_for_truncate(inode);
4145 
4146 	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
4147 	if (IS_ERR(handle)) {
4148 		err = PTR_ERR(handle);
4149 		goto out_trace;
4150 	}
4151 
4152 	if (inode->i_size & (inode->i_sb->s_blocksize - 1))
4153 		ext4_block_truncate_page(handle, mapping, inode->i_size);
4154 
4155 	/*
4156 	 * We add the inode to the orphan list, so that if this
4157 	 * truncate spans multiple transactions, and we crash, we will
4158 	 * resume the truncate when the filesystem recovers.  It also
4159 	 * marks the inode dirty, to catch the new size.
4160 	 *
4161 	 * Implication: the file must always be in a sane, consistent
4162 	 * truncatable state while each transaction commits.
4163 	 */
4164 	err = ext4_orphan_add(handle, inode);
4165 	if (err)
4166 		goto out_stop;
4167 
4168 	down_write(&EXT4_I(inode)->i_data_sem);
4169 
4170 	ext4_discard_preallocations(inode, 0);
4171 
4172 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4173 		err = ext4_ext_truncate(handle, inode);
4174 	else
4175 		ext4_ind_truncate(handle, inode);
4176 
4177 	up_write(&ei->i_data_sem);
4178 	if (err)
4179 		goto out_stop;
4180 
4181 	if (IS_SYNC(inode))
4182 		ext4_handle_sync(handle);
4183 
4184 out_stop:
4185 	/*
4186 	 * If this was a simple ftruncate() and the file will remain alive,
4187 	 * then we need to clear up the orphan record which we created above.
4188 	 * However, if this was a real unlink then we were called by
4189 	 * ext4_evict_inode(), and we allow that function to clean up the
4190 	 * orphan info for us.
4191 	 */
4192 	if (inode->i_nlink)
4193 		ext4_orphan_del(handle, inode);
4194 
4195 	inode->i_mtime = inode_set_ctime_current(inode);
4196 	err2 = ext4_mark_inode_dirty(handle, inode);
4197 	if (unlikely(err2 && !err))
4198 		err = err2;
4199 	ext4_journal_stop(handle);
4200 
4201 out_trace:
4202 	trace_ext4_truncate_exit(inode);
4203 	return err;
4204 }
4205 
ext4_inode_peek_iversion(const struct inode * inode)4206 static inline u64 ext4_inode_peek_iversion(const struct inode *inode)
4207 {
4208 	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4209 		return inode_peek_iversion_raw(inode);
4210 	else
4211 		return inode_peek_iversion(inode);
4212 }
4213 
ext4_inode_blocks_set(struct ext4_inode * raw_inode,struct ext4_inode_info * ei)4214 static int ext4_inode_blocks_set(struct ext4_inode *raw_inode,
4215 				 struct ext4_inode_info *ei)
4216 {
4217 	struct inode *inode = &(ei->vfs_inode);
4218 	u64 i_blocks = READ_ONCE(inode->i_blocks);
4219 	struct super_block *sb = inode->i_sb;
4220 
4221 	if (i_blocks <= ~0U) {
4222 		/*
4223 		 * i_blocks can be represented in a 32 bit variable
4224 		 * as multiple of 512 bytes
4225 		 */
4226 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4227 		raw_inode->i_blocks_high = 0;
4228 		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4229 		return 0;
4230 	}
4231 
4232 	/*
4233 	 * This should never happen since sb->s_maxbytes should not have
4234 	 * allowed this, sb->s_maxbytes was set according to the huge_file
4235 	 * feature in ext4_fill_super().
4236 	 */
4237 	if (!ext4_has_feature_huge_file(sb))
4238 		return -EFSCORRUPTED;
4239 
4240 	if (i_blocks <= 0xffffffffffffULL) {
4241 		/*
4242 		 * i_blocks can be represented in a 48 bit variable
4243 		 * as multiple of 512 bytes
4244 		 */
4245 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4246 		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4247 		ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4248 	} else {
4249 		ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE);
4250 		/* i_block is stored in file system block size */
4251 		i_blocks = i_blocks >> (inode->i_blkbits - 9);
4252 		raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4253 		raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4254 	}
4255 	return 0;
4256 }
4257 
ext4_fill_raw_inode(struct inode * inode,struct ext4_inode * raw_inode)4258 static int ext4_fill_raw_inode(struct inode *inode, struct ext4_inode *raw_inode)
4259 {
4260 	struct ext4_inode_info *ei = EXT4_I(inode);
4261 	uid_t i_uid;
4262 	gid_t i_gid;
4263 	projid_t i_projid;
4264 	int block;
4265 	int err;
4266 
4267 	err = ext4_inode_blocks_set(raw_inode, ei);
4268 
4269 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4270 	i_uid = i_uid_read(inode);
4271 	i_gid = i_gid_read(inode);
4272 	i_projid = from_kprojid(&init_user_ns, ei->i_projid);
4273 	if (!(test_opt(inode->i_sb, NO_UID32))) {
4274 		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
4275 		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
4276 		/*
4277 		 * Fix up interoperability with old kernels. Otherwise,
4278 		 * old inodes get re-used with the upper 16 bits of the
4279 		 * uid/gid intact.
4280 		 */
4281 		if (ei->i_dtime && list_empty(&ei->i_orphan)) {
4282 			raw_inode->i_uid_high = 0;
4283 			raw_inode->i_gid_high = 0;
4284 		} else {
4285 			raw_inode->i_uid_high =
4286 				cpu_to_le16(high_16_bits(i_uid));
4287 			raw_inode->i_gid_high =
4288 				cpu_to_le16(high_16_bits(i_gid));
4289 		}
4290 	} else {
4291 		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));
4292 		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(i_gid));
4293 		raw_inode->i_uid_high = 0;
4294 		raw_inode->i_gid_high = 0;
4295 	}
4296 	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4297 
4298 	EXT4_INODE_SET_CTIME(inode, raw_inode);
4299 	EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4300 	EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4301 	EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4302 
4303 	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4304 	raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
4305 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT)))
4306 		raw_inode->i_file_acl_high =
4307 			cpu_to_le16(ei->i_file_acl >> 32);
4308 	raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4309 	ext4_isize_set(raw_inode, ei->i_disksize);
4310 
4311 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4312 	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4313 		if (old_valid_dev(inode->i_rdev)) {
4314 			raw_inode->i_block[0] =
4315 				cpu_to_le32(old_encode_dev(inode->i_rdev));
4316 			raw_inode->i_block[1] = 0;
4317 		} else {
4318 			raw_inode->i_block[0] = 0;
4319 			raw_inode->i_block[1] =
4320 				cpu_to_le32(new_encode_dev(inode->i_rdev));
4321 			raw_inode->i_block[2] = 0;
4322 		}
4323 	} else if (!ext4_has_inline_data(inode)) {
4324 		for (block = 0; block < EXT4_N_BLOCKS; block++)
4325 			raw_inode->i_block[block] = ei->i_data[block];
4326 	}
4327 
4328 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4329 		u64 ivers = ext4_inode_peek_iversion(inode);
4330 
4331 		raw_inode->i_disk_version = cpu_to_le32(ivers);
4332 		if (ei->i_extra_isize) {
4333 			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4334 				raw_inode->i_version_hi =
4335 					cpu_to_le32(ivers >> 32);
4336 			raw_inode->i_extra_isize =
4337 				cpu_to_le16(ei->i_extra_isize);
4338 		}
4339 	}
4340 
4341 	if (i_projid != EXT4_DEF_PROJID &&
4342 	    !ext4_has_feature_project(inode->i_sb))
4343 		err = err ?: -EFSCORRUPTED;
4344 
4345 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4346 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4347 		raw_inode->i_projid = cpu_to_le32(i_projid);
4348 
4349 	ext4_inode_csum_set(inode, raw_inode, ei);
4350 	return err;
4351 }
4352 
4353 /*
4354  * ext4_get_inode_loc returns with an extra refcount against the inode's
4355  * underlying buffer_head on success. If we pass 'inode' and it does not
4356  * have in-inode xattr, we have all inode data in memory that is needed
4357  * to recreate the on-disk version of this inode.
4358  */
__ext4_get_inode_loc(struct super_block * sb,unsigned long ino,struct inode * inode,struct ext4_iloc * iloc,ext4_fsblk_t * ret_block)4359 static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
4360 				struct inode *inode, struct ext4_iloc *iloc,
4361 				ext4_fsblk_t *ret_block)
4362 {
4363 	struct ext4_group_desc	*gdp;
4364 	struct buffer_head	*bh;
4365 	ext4_fsblk_t		block;
4366 	struct blk_plug		plug;
4367 	int			inodes_per_block, inode_offset;
4368 
4369 	iloc->bh = NULL;
4370 	if (ino < EXT4_ROOT_INO ||
4371 	    ino > le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))
4372 		return -EFSCORRUPTED;
4373 
4374 	iloc->block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
4375 	gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4376 	if (!gdp)
4377 		return -EIO;
4378 
4379 	/*
4380 	 * Figure out the offset within the block group inode table
4381 	 */
4382 	inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
4383 	inode_offset = ((ino - 1) %
4384 			EXT4_INODES_PER_GROUP(sb));
4385 	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4386 
4387 	block = ext4_inode_table(sb, gdp);
4388 	if ((block <= le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) ||
4389 	    (block >= ext4_blocks_count(EXT4_SB(sb)->s_es))) {
4390 		ext4_error(sb, "Invalid inode table block %llu in "
4391 			   "block_group %u", block, iloc->block_group);
4392 		return -EFSCORRUPTED;
4393 	}
4394 	block += (inode_offset / inodes_per_block);
4395 
4396 	bh = sb_getblk(sb, block);
4397 	if (unlikely(!bh))
4398 		return -ENOMEM;
4399 	if (ext4_buffer_uptodate(bh))
4400 		goto has_buffer;
4401 
4402 	lock_buffer(bh);
4403 	if (ext4_buffer_uptodate(bh)) {
4404 		/* Someone brought it uptodate while we waited */
4405 		unlock_buffer(bh);
4406 		goto has_buffer;
4407 	}
4408 
4409 	/*
4410 	 * If we have all information of the inode in memory and this
4411 	 * is the only valid inode in the block, we need not read the
4412 	 * block.
4413 	 */
4414 	if (inode && !ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4415 		struct buffer_head *bitmap_bh;
4416 		int i, start;
4417 
4418 		start = inode_offset & ~(inodes_per_block - 1);
4419 
4420 		/* Is the inode bitmap in cache? */
4421 		bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4422 		if (unlikely(!bitmap_bh))
4423 			goto make_io;
4424 
4425 		/*
4426 		 * If the inode bitmap isn't in cache then the
4427 		 * optimisation may end up performing two reads instead
4428 		 * of one, so skip it.
4429 		 */
4430 		if (!buffer_uptodate(bitmap_bh)) {
4431 			brelse(bitmap_bh);
4432 			goto make_io;
4433 		}
4434 		for (i = start; i < start + inodes_per_block; i++) {
4435 			if (i == inode_offset)
4436 				continue;
4437 			if (ext4_test_bit(i, bitmap_bh->b_data))
4438 				break;
4439 		}
4440 		brelse(bitmap_bh);
4441 		if (i == start + inodes_per_block) {
4442 			struct ext4_inode *raw_inode =
4443 				(struct ext4_inode *) (bh->b_data + iloc->offset);
4444 
4445 			/* all other inodes are free, so skip I/O */
4446 			memset(bh->b_data, 0, bh->b_size);
4447 			if (!ext4_test_inode_state(inode, EXT4_STATE_NEW))
4448 				ext4_fill_raw_inode(inode, raw_inode);
4449 			set_buffer_uptodate(bh);
4450 			unlock_buffer(bh);
4451 			goto has_buffer;
4452 		}
4453 	}
4454 
4455 make_io:
4456 	/*
4457 	 * If we need to do any I/O, try to pre-readahead extra
4458 	 * blocks from the inode table.
4459 	 */
4460 	blk_start_plug(&plug);
4461 	if (EXT4_SB(sb)->s_inode_readahead_blks) {
4462 		ext4_fsblk_t b, end, table;
4463 		unsigned num;
4464 		__u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
4465 
4466 		table = ext4_inode_table(sb, gdp);
4467 		/* s_inode_readahead_blks is always a power of 2 */
4468 		b = block & ~((ext4_fsblk_t) ra_blks - 1);
4469 		if (table > b)
4470 			b = table;
4471 		end = b + ra_blks;
4472 		num = EXT4_INODES_PER_GROUP(sb);
4473 		if (ext4_has_group_desc_csum(sb))
4474 			num -= ext4_itable_unused_count(sb, gdp);
4475 		table += num / inodes_per_block;
4476 		if (end > table)
4477 			end = table;
4478 		while (b <= end)
4479 			ext4_sb_breadahead_unmovable(sb, b++);
4480 	}
4481 
4482 	/*
4483 	 * There are other valid inodes in the buffer, this inode
4484 	 * has in-inode xattrs, or we don't have this inode in memory.
4485 	 * Read the block from disk.
4486 	 */
4487 	trace_ext4_load_inode(sb, ino);
4488 	ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
4489 	blk_finish_plug(&plug);
4490 	wait_on_buffer(bh);
4491 	ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
4492 	if (!buffer_uptodate(bh)) {
4493 		if (ret_block)
4494 			*ret_block = block;
4495 		brelse(bh);
4496 		return -EIO;
4497 	}
4498 has_buffer:
4499 	iloc->bh = bh;
4500 	return 0;
4501 }
4502 
__ext4_get_inode_loc_noinmem(struct inode * inode,struct ext4_iloc * iloc)4503 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
4504 					struct ext4_iloc *iloc)
4505 {
4506 	ext4_fsblk_t err_blk = 0;
4507 	int ret;
4508 
4509 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, NULL, iloc,
4510 					&err_blk);
4511 
4512 	if (ret == -EIO)
4513 		ext4_error_inode_block(inode, err_blk, EIO,
4514 					"unable to read itable block");
4515 
4516 	return ret;
4517 }
4518 
ext4_get_inode_loc(struct inode * inode,struct ext4_iloc * iloc)4519 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4520 {
4521 	ext4_fsblk_t err_blk = 0;
4522 	int ret;
4523 
4524 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, inode, iloc,
4525 					&err_blk);
4526 
4527 	if (ret == -EIO)
4528 		ext4_error_inode_block(inode, err_blk, EIO,
4529 					"unable to read itable block");
4530 
4531 	return ret;
4532 }
4533 
4534 
ext4_get_fc_inode_loc(struct super_block * sb,unsigned long ino,struct ext4_iloc * iloc)4535 int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino,
4536 			  struct ext4_iloc *iloc)
4537 {
4538 	return __ext4_get_inode_loc(sb, ino, NULL, iloc, NULL);
4539 }
4540 
ext4_should_enable_dax(struct inode * inode)4541 static bool ext4_should_enable_dax(struct inode *inode)
4542 {
4543 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4544 
4545 	if (test_opt2(inode->i_sb, DAX_NEVER))
4546 		return false;
4547 	if (!S_ISREG(inode->i_mode))
4548 		return false;
4549 	if (ext4_should_journal_data(inode))
4550 		return false;
4551 	if (ext4_has_inline_data(inode))
4552 		return false;
4553 	if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT))
4554 		return false;
4555 	if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY))
4556 		return false;
4557 	if (!test_bit(EXT4_FLAGS_BDEV_IS_DAX, &sbi->s_ext4_flags))
4558 		return false;
4559 	if (test_opt(inode->i_sb, DAX_ALWAYS))
4560 		return true;
4561 
4562 	return ext4_test_inode_flag(inode, EXT4_INODE_DAX);
4563 }
4564 
ext4_set_inode_flags(struct inode * inode,bool init)4565 void ext4_set_inode_flags(struct inode *inode, bool init)
4566 {
4567 	unsigned int flags = EXT4_I(inode)->i_flags;
4568 	unsigned int new_fl = 0;
4569 
4570 	WARN_ON_ONCE(IS_DAX(inode) && init);
4571 
4572 	if (flags & EXT4_SYNC_FL)
4573 		new_fl |= S_SYNC;
4574 	if (flags & EXT4_APPEND_FL)
4575 		new_fl |= S_APPEND;
4576 	if (flags & EXT4_IMMUTABLE_FL)
4577 		new_fl |= S_IMMUTABLE;
4578 	if (flags & EXT4_NOATIME_FL)
4579 		new_fl |= S_NOATIME;
4580 	if (flags & EXT4_DIRSYNC_FL)
4581 		new_fl |= S_DIRSYNC;
4582 
4583 	/* Because of the way inode_set_flags() works we must preserve S_DAX
4584 	 * here if already set. */
4585 	new_fl |= (inode->i_flags & S_DAX);
4586 	if (init && ext4_should_enable_dax(inode))
4587 		new_fl |= S_DAX;
4588 
4589 	if (flags & EXT4_ENCRYPT_FL)
4590 		new_fl |= S_ENCRYPTED;
4591 	if (flags & EXT4_CASEFOLD_FL)
4592 		new_fl |= S_CASEFOLD;
4593 	if (flags & EXT4_VERITY_FL)
4594 		new_fl |= S_VERITY;
4595 	inode_set_flags(inode, new_fl,
4596 			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
4597 			S_ENCRYPTED|S_CASEFOLD|S_VERITY);
4598 }
4599 
ext4_inode_blocks(struct ext4_inode * raw_inode,struct ext4_inode_info * ei)4600 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4601 				  struct ext4_inode_info *ei)
4602 {
4603 	blkcnt_t i_blocks ;
4604 	struct inode *inode = &(ei->vfs_inode);
4605 	struct super_block *sb = inode->i_sb;
4606 
4607 	if (ext4_has_feature_huge_file(sb)) {
4608 		/* we are using combined 48 bit field */
4609 		i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4610 					le32_to_cpu(raw_inode->i_blocks_lo);
4611 		if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) {
4612 			/* i_blocks represent file system block size */
4613 			return i_blocks  << (inode->i_blkbits - 9);
4614 		} else {
4615 			return i_blocks;
4616 		}
4617 	} else {
4618 		return le32_to_cpu(raw_inode->i_blocks_lo);
4619 	}
4620 }
4621 
ext4_iget_extra_inode(struct inode * inode,struct ext4_inode * raw_inode,struct ext4_inode_info * ei)4622 static inline int ext4_iget_extra_inode(struct inode *inode,
4623 					 struct ext4_inode *raw_inode,
4624 					 struct ext4_inode_info *ei)
4625 {
4626 	__le32 *magic = (void *)raw_inode +
4627 			EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
4628 
4629 	if (EXT4_INODE_HAS_XATTR_SPACE(inode)  &&
4630 	    *magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
4631 		int err;
4632 
4633 		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
4634 		err = ext4_find_inline_data_nolock(inode);
4635 		if (!err && ext4_has_inline_data(inode))
4636 			ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
4637 		return err;
4638 	} else
4639 		EXT4_I(inode)->i_inline_off = 0;
4640 	return 0;
4641 }
4642 
ext4_get_projid(struct inode * inode,kprojid_t * projid)4643 int ext4_get_projid(struct inode *inode, kprojid_t *projid)
4644 {
4645 	if (!ext4_has_feature_project(inode->i_sb))
4646 		return -EOPNOTSUPP;
4647 	*projid = EXT4_I(inode)->i_projid;
4648 	return 0;
4649 }
4650 
4651 /*
4652  * ext4 has self-managed i_version for ea inodes, it stores the lower 32bit of
4653  * refcount in i_version, so use raw values if inode has EXT4_EA_INODE_FL flag
4654  * set.
4655  */
ext4_inode_set_iversion_queried(struct inode * inode,u64 val)4656 static inline void ext4_inode_set_iversion_queried(struct inode *inode, u64 val)
4657 {
4658 	if (unlikely(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4659 		inode_set_iversion_raw(inode, val);
4660 	else
4661 		inode_set_iversion_queried(inode, val);
4662 }
4663 
check_igot_inode(struct inode * inode,ext4_iget_flags flags)4664 static const char *check_igot_inode(struct inode *inode, ext4_iget_flags flags)
4665 
4666 {
4667 	if (flags & EXT4_IGET_EA_INODE) {
4668 		if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4669 			return "missing EA_INODE flag";
4670 		if (ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
4671 		    EXT4_I(inode)->i_file_acl)
4672 			return "ea_inode with extended attributes";
4673 	} else {
4674 		if ((EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL))
4675 			return "unexpected EA_INODE flag";
4676 	}
4677 	if (is_bad_inode(inode) && !(flags & EXT4_IGET_BAD))
4678 		return "unexpected bad inode w/o EXT4_IGET_BAD";
4679 	return NULL;
4680 }
4681 
__ext4_iget(struct super_block * sb,unsigned long ino,ext4_iget_flags flags,const char * function,unsigned int line)4682 struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
4683 			  ext4_iget_flags flags, const char *function,
4684 			  unsigned int line)
4685 {
4686 	struct ext4_iloc iloc;
4687 	struct ext4_inode *raw_inode;
4688 	struct ext4_inode_info *ei;
4689 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
4690 	struct inode *inode;
4691 	const char *err_str;
4692 	journal_t *journal = EXT4_SB(sb)->s_journal;
4693 	long ret;
4694 	loff_t size;
4695 	int block;
4696 	uid_t i_uid;
4697 	gid_t i_gid;
4698 	projid_t i_projid;
4699 
4700 	if ((!(flags & EXT4_IGET_SPECIAL) &&
4701 	     ((ino < EXT4_FIRST_INO(sb) && ino != EXT4_ROOT_INO) ||
4702 	      ino == le32_to_cpu(es->s_usr_quota_inum) ||
4703 	      ino == le32_to_cpu(es->s_grp_quota_inum) ||
4704 	      ino == le32_to_cpu(es->s_prj_quota_inum) ||
4705 	      ino == le32_to_cpu(es->s_orphan_file_inum))) ||
4706 	    (ino < EXT4_ROOT_INO) ||
4707 	    (ino > le32_to_cpu(es->s_inodes_count))) {
4708 		if (flags & EXT4_IGET_HANDLE)
4709 			return ERR_PTR(-ESTALE);
4710 		__ext4_error(sb, function, line, false, EFSCORRUPTED, 0,
4711 			     "inode #%lu: comm %s: iget: illegal inode #",
4712 			     ino, current->comm);
4713 		return ERR_PTR(-EFSCORRUPTED);
4714 	}
4715 
4716 	inode = iget_locked(sb, ino);
4717 	if (!inode)
4718 		return ERR_PTR(-ENOMEM);
4719 	if (!(inode->i_state & I_NEW)) {
4720 		if ((err_str = check_igot_inode(inode, flags)) != NULL) {
4721 			ext4_error_inode(inode, function, line, 0, err_str);
4722 			iput(inode);
4723 			return ERR_PTR(-EFSCORRUPTED);
4724 		}
4725 		return inode;
4726 	}
4727 
4728 	ei = EXT4_I(inode);
4729 	iloc.bh = NULL;
4730 
4731 	ret = __ext4_get_inode_loc_noinmem(inode, &iloc);
4732 	if (ret < 0)
4733 		goto bad_inode;
4734 	raw_inode = ext4_raw_inode(&iloc);
4735 
4736 	if ((flags & EXT4_IGET_HANDLE) &&
4737 	    (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) {
4738 		ret = -ESTALE;
4739 		goto bad_inode;
4740 	}
4741 
4742 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4743 		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4744 		if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4745 			EXT4_INODE_SIZE(inode->i_sb) ||
4746 		    (ei->i_extra_isize & 3)) {
4747 			ext4_error_inode(inode, function, line, 0,
4748 					 "iget: bad extra_isize %u "
4749 					 "(inode size %u)",
4750 					 ei->i_extra_isize,
4751 					 EXT4_INODE_SIZE(inode->i_sb));
4752 			ret = -EFSCORRUPTED;
4753 			goto bad_inode;
4754 		}
4755 	} else
4756 		ei->i_extra_isize = 0;
4757 
4758 	/* Precompute checksum seed for inode metadata */
4759 	if (ext4_has_metadata_csum(sb)) {
4760 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4761 		__u32 csum;
4762 		__le32 inum = cpu_to_le32(inode->i_ino);
4763 		__le32 gen = raw_inode->i_generation;
4764 		csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
4765 				   sizeof(inum));
4766 		ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
4767 					      sizeof(gen));
4768 	}
4769 
4770 	if ((!ext4_inode_csum_verify(inode, raw_inode, ei) ||
4771 	    ext4_simulate_fail(sb, EXT4_SIM_INODE_CRC)) &&
4772 	     (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY))) {
4773 		ext4_error_inode_err(inode, function, line, 0,
4774 				EFSBADCRC, "iget: checksum invalid");
4775 		ret = -EFSBADCRC;
4776 		goto bad_inode;
4777 	}
4778 
4779 	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4780 	i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4781 	i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4782 	if (ext4_has_feature_project(sb) &&
4783 	    EXT4_INODE_SIZE(sb) > EXT4_GOOD_OLD_INODE_SIZE &&
4784 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_projid))
4785 		i_projid = (projid_t)le32_to_cpu(raw_inode->i_projid);
4786 	else
4787 		i_projid = EXT4_DEF_PROJID;
4788 
4789 	if (!(test_opt(inode->i_sb, NO_UID32))) {
4790 		i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4791 		i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4792 	}
4793 	i_uid_write(inode, i_uid);
4794 	i_gid_write(inode, i_gid);
4795 	ei->i_projid = make_kprojid(&init_user_ns, i_projid);
4796 	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
4797 
4798 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
4799 	ei->i_inline_off = 0;
4800 	ei->i_dir_start_lookup = 0;
4801 	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4802 	/* We now have enough fields to check if the inode was active or not.
4803 	 * This is needed because nfsd might try to access dead inodes
4804 	 * the test is that same one that e2fsck uses
4805 	 * NeilBrown 1999oct15
4806 	 */
4807 	if (inode->i_nlink == 0) {
4808 		if ((inode->i_mode == 0 || flags & EXT4_IGET_SPECIAL ||
4809 		     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) &&
4810 		    ino != EXT4_BOOT_LOADER_INO) {
4811 			/* this inode is deleted or unallocated */
4812 			if (flags & EXT4_IGET_SPECIAL) {
4813 				ext4_error_inode(inode, function, line, 0,
4814 						 "iget: special inode unallocated");
4815 				ret = -EFSCORRUPTED;
4816 			} else
4817 				ret = -ESTALE;
4818 			goto bad_inode;
4819 		}
4820 		/* The only unlinked inodes we let through here have
4821 		 * valid i_mode and are being read by the orphan
4822 		 * recovery code: that's fine, we're about to complete
4823 		 * the process of deleting those.
4824 		 * OR it is the EXT4_BOOT_LOADER_INO which is
4825 		 * not initialized on a new filesystem. */
4826 	}
4827 	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4828 	ext4_set_inode_flags(inode, true);
4829 	inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4830 	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4831 	if (ext4_has_feature_64bit(sb))
4832 		ei->i_file_acl |=
4833 			((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4834 	inode->i_size = ext4_isize(sb, raw_inode);
4835 	if ((size = i_size_read(inode)) < 0) {
4836 		ext4_error_inode(inode, function, line, 0,
4837 				 "iget: bad i_size value: %lld", size);
4838 		ret = -EFSCORRUPTED;
4839 		goto bad_inode;
4840 	}
4841 	/*
4842 	 * If dir_index is not enabled but there's dir with INDEX flag set,
4843 	 * we'd normally treat htree data as empty space. But with metadata
4844 	 * checksumming that corrupts checksums so forbid that.
4845 	 */
4846 	if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) &&
4847 	    ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) {
4848 		ext4_error_inode(inode, function, line, 0,
4849 			 "iget: Dir with htree data on filesystem without dir_index feature.");
4850 		ret = -EFSCORRUPTED;
4851 		goto bad_inode;
4852 	}
4853 	ei->i_disksize = inode->i_size;
4854 #ifdef CONFIG_QUOTA
4855 	ei->i_reserved_quota = 0;
4856 #endif
4857 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4858 	ei->i_block_group = iloc.block_group;
4859 	ei->i_last_alloc_group = ~0;
4860 	/*
4861 	 * NOTE! The in-memory inode i_data array is in little-endian order
4862 	 * even on big-endian machines: we do NOT byteswap the block numbers!
4863 	 */
4864 	for (block = 0; block < EXT4_N_BLOCKS; block++)
4865 		ei->i_data[block] = raw_inode->i_block[block];
4866 	INIT_LIST_HEAD(&ei->i_orphan);
4867 	ext4_fc_init_inode(&ei->vfs_inode);
4868 
4869 	/*
4870 	 * Set transaction id's of transactions that have to be committed
4871 	 * to finish f[data]sync. We set them to currently running transaction
4872 	 * as we cannot be sure that the inode or some of its metadata isn't
4873 	 * part of the transaction - the inode could have been reclaimed and
4874 	 * now it is reread from disk.
4875 	 */
4876 	if (journal) {
4877 		transaction_t *transaction;
4878 		tid_t tid;
4879 
4880 		read_lock(&journal->j_state_lock);
4881 		if (journal->j_running_transaction)
4882 			transaction = journal->j_running_transaction;
4883 		else
4884 			transaction = journal->j_committing_transaction;
4885 		if (transaction)
4886 			tid = transaction->t_tid;
4887 		else
4888 			tid = journal->j_commit_sequence;
4889 		read_unlock(&journal->j_state_lock);
4890 		ei->i_sync_tid = tid;
4891 		ei->i_datasync_tid = tid;
4892 	}
4893 
4894 	if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4895 		if (ei->i_extra_isize == 0) {
4896 			/* The extra space is currently unused. Use it. */
4897 			BUILD_BUG_ON(sizeof(struct ext4_inode) & 3);
4898 			ei->i_extra_isize = sizeof(struct ext4_inode) -
4899 					    EXT4_GOOD_OLD_INODE_SIZE;
4900 		} else {
4901 			ret = ext4_iget_extra_inode(inode, raw_inode, ei);
4902 			if (ret)
4903 				goto bad_inode;
4904 		}
4905 	}
4906 
4907 	EXT4_INODE_GET_CTIME(inode, raw_inode);
4908 	EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4909 	EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4910 	EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4911 
4912 	if (likely(!test_opt2(inode->i_sb, HURD_COMPAT))) {
4913 		u64 ivers = le32_to_cpu(raw_inode->i_disk_version);
4914 
4915 		if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4916 			if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4917 				ivers |=
4918 		    (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4919 		}
4920 		ext4_inode_set_iversion_queried(inode, ivers);
4921 	}
4922 
4923 	ret = 0;
4924 	if (ei->i_file_acl &&
4925 	    !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
4926 		ext4_error_inode(inode, function, line, 0,
4927 				 "iget: bad extended attribute block %llu",
4928 				 ei->i_file_acl);
4929 		ret = -EFSCORRUPTED;
4930 		goto bad_inode;
4931 	} else if (!ext4_has_inline_data(inode)) {
4932 		/* validate the block references in the inode */
4933 		if (!(EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) &&
4934 			(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4935 			(S_ISLNK(inode->i_mode) &&
4936 			!ext4_inode_is_fast_symlink(inode)))) {
4937 			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
4938 				ret = ext4_ext_check_inode(inode);
4939 			else
4940 				ret = ext4_ind_check_inode(inode);
4941 		}
4942 	}
4943 	if (ret)
4944 		goto bad_inode;
4945 
4946 	if (S_ISREG(inode->i_mode)) {
4947 		inode->i_op = &ext4_file_inode_operations;
4948 		inode->i_fop = &ext4_file_operations;
4949 		ext4_set_aops(inode);
4950 	} else if (S_ISDIR(inode->i_mode)) {
4951 		inode->i_op = &ext4_dir_inode_operations;
4952 		inode->i_fop = &ext4_dir_operations;
4953 	} else if (S_ISLNK(inode->i_mode)) {
4954 		/* VFS does not allow setting these so must be corruption */
4955 		if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) {
4956 			ext4_error_inode(inode, function, line, 0,
4957 					 "iget: immutable or append flags "
4958 					 "not allowed on symlinks");
4959 			ret = -EFSCORRUPTED;
4960 			goto bad_inode;
4961 		}
4962 		if (IS_ENCRYPTED(inode)) {
4963 			inode->i_op = &ext4_encrypted_symlink_inode_operations;
4964 		} else if (ext4_inode_is_fast_symlink(inode)) {
4965 			inode->i_link = (char *)ei->i_data;
4966 			inode->i_op = &ext4_fast_symlink_inode_operations;
4967 			nd_terminate_link(ei->i_data, inode->i_size,
4968 				sizeof(ei->i_data) - 1);
4969 		} else {
4970 			inode->i_op = &ext4_symlink_inode_operations;
4971 		}
4972 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4973 	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4974 		inode->i_op = &ext4_special_inode_operations;
4975 		if (raw_inode->i_block[0])
4976 			init_special_inode(inode, inode->i_mode,
4977 			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4978 		else
4979 			init_special_inode(inode, inode->i_mode,
4980 			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4981 	} else if (ino == EXT4_BOOT_LOADER_INO) {
4982 		make_bad_inode(inode);
4983 	} else {
4984 		ret = -EFSCORRUPTED;
4985 		ext4_error_inode(inode, function, line, 0,
4986 				 "iget: bogus i_mode (%o)", inode->i_mode);
4987 		goto bad_inode;
4988 	}
4989 	if (IS_CASEFOLDED(inode) && !ext4_has_feature_casefold(inode->i_sb)) {
4990 		ext4_error_inode(inode, function, line, 0,
4991 				 "casefold flag without casefold feature");
4992 		ret = -EFSCORRUPTED;
4993 		goto bad_inode;
4994 	}
4995 	if ((err_str = check_igot_inode(inode, flags)) != NULL) {
4996 		ext4_error_inode(inode, function, line, 0, err_str);
4997 		ret = -EFSCORRUPTED;
4998 		goto bad_inode;
4999 	}
5000 
5001 	brelse(iloc.bh);
5002 	unlock_new_inode(inode);
5003 	return inode;
5004 
5005 bad_inode:
5006 	brelse(iloc.bh);
5007 	iget_failed(inode);
5008 	return ERR_PTR(ret);
5009 }
5010 
__ext4_update_other_inode_time(struct super_block * sb,unsigned long orig_ino,unsigned long ino,struct ext4_inode * raw_inode)5011 static void __ext4_update_other_inode_time(struct super_block *sb,
5012 					   unsigned long orig_ino,
5013 					   unsigned long ino,
5014 					   struct ext4_inode *raw_inode)
5015 {
5016 	struct inode *inode;
5017 
5018 	inode = find_inode_by_ino_rcu(sb, ino);
5019 	if (!inode)
5020 		return;
5021 
5022 	if (!inode_is_dirtytime_only(inode))
5023 		return;
5024 
5025 	spin_lock(&inode->i_lock);
5026 	if (inode_is_dirtytime_only(inode)) {
5027 		struct ext4_inode_info	*ei = EXT4_I(inode);
5028 
5029 		inode->i_state &= ~I_DIRTY_TIME;
5030 		spin_unlock(&inode->i_lock);
5031 
5032 		spin_lock(&ei->i_raw_lock);
5033 		EXT4_INODE_SET_CTIME(inode, raw_inode);
5034 		EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5035 		EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5036 		ext4_inode_csum_set(inode, raw_inode, ei);
5037 		spin_unlock(&ei->i_raw_lock);
5038 		trace_ext4_other_inode_update_time(inode, orig_ino);
5039 		return;
5040 	}
5041 	spin_unlock(&inode->i_lock);
5042 }
5043 
5044 /*
5045  * Opportunistically update the other time fields for other inodes in
5046  * the same inode table block.
5047  */
ext4_update_other_inodes_time(struct super_block * sb,unsigned long orig_ino,char * buf)5048 static void ext4_update_other_inodes_time(struct super_block *sb,
5049 					  unsigned long orig_ino, char *buf)
5050 {
5051 	unsigned long ino;
5052 	int i, inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
5053 	int inode_size = EXT4_INODE_SIZE(sb);
5054 
5055 	/*
5056 	 * Calculate the first inode in the inode table block.  Inode
5057 	 * numbers are one-based.  That is, the first inode in a block
5058 	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
5059 	 */
5060 	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
5061 	rcu_read_lock();
5062 	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
5063 		if (ino == orig_ino)
5064 			continue;
5065 		__ext4_update_other_inode_time(sb, orig_ino, ino,
5066 					       (struct ext4_inode *)buf);
5067 	}
5068 	rcu_read_unlock();
5069 }
5070 
5071 /*
5072  * Post the struct inode info into an on-disk inode location in the
5073  * buffer-cache.  This gobbles the caller's reference to the
5074  * buffer_head in the inode location struct.
5075  *
5076  * The caller must have write access to iloc->bh.
5077  */
ext4_do_update_inode(handle_t * handle,struct inode * inode,struct ext4_iloc * iloc)5078 static int ext4_do_update_inode(handle_t *handle,
5079 				struct inode *inode,
5080 				struct ext4_iloc *iloc)
5081 {
5082 	struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
5083 	struct ext4_inode_info *ei = EXT4_I(inode);
5084 	struct buffer_head *bh = iloc->bh;
5085 	struct super_block *sb = inode->i_sb;
5086 	int err;
5087 	int need_datasync = 0, set_large_file = 0;
5088 
5089 	spin_lock(&ei->i_raw_lock);
5090 
5091 	/*
5092 	 * For fields not tracked in the in-memory inode, initialise them
5093 	 * to zero for new inodes.
5094 	 */
5095 	if (ext4_test_inode_state(inode, EXT4_STATE_NEW))
5096 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5097 
5098 	if (READ_ONCE(ei->i_disksize) != ext4_isize(inode->i_sb, raw_inode))
5099 		need_datasync = 1;
5100 	if (ei->i_disksize > 0x7fffffffULL) {
5101 		if (!ext4_has_feature_large_file(sb) ||
5102 		    EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV))
5103 			set_large_file = 1;
5104 	}
5105 
5106 	err = ext4_fill_raw_inode(inode, raw_inode);
5107 	spin_unlock(&ei->i_raw_lock);
5108 	if (err) {
5109 		EXT4_ERROR_INODE(inode, "corrupted inode contents");
5110 		goto out_brelse;
5111 	}
5112 
5113 	if (inode->i_sb->s_flags & SB_LAZYTIME)
5114 		ext4_update_other_inodes_time(inode->i_sb, inode->i_ino,
5115 					      bh->b_data);
5116 
5117 	BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5118 	err = ext4_handle_dirty_metadata(handle, NULL, bh);
5119 	if (err)
5120 		goto out_error;
5121 	ext4_clear_inode_state(inode, EXT4_STATE_NEW);
5122 	if (set_large_file) {
5123 		BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get write access");
5124 		err = ext4_journal_get_write_access(handle, sb,
5125 						    EXT4_SB(sb)->s_sbh,
5126 						    EXT4_JTR_NONE);
5127 		if (err)
5128 			goto out_error;
5129 		lock_buffer(EXT4_SB(sb)->s_sbh);
5130 		ext4_set_feature_large_file(sb);
5131 		ext4_superblock_csum_set(sb);
5132 		unlock_buffer(EXT4_SB(sb)->s_sbh);
5133 		ext4_handle_sync(handle);
5134 		err = ext4_handle_dirty_metadata(handle, NULL,
5135 						 EXT4_SB(sb)->s_sbh);
5136 	}
5137 	ext4_update_inode_fsync_trans(handle, inode, need_datasync);
5138 out_error:
5139 	ext4_std_error(inode->i_sb, err);
5140 out_brelse:
5141 	brelse(bh);
5142 	return err;
5143 }
5144 
5145 /*
5146  * ext4_write_inode()
5147  *
5148  * We are called from a few places:
5149  *
5150  * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
5151  *   Here, there will be no transaction running. We wait for any running
5152  *   transaction to commit.
5153  *
5154  * - Within flush work (sys_sync(), kupdate and such).
5155  *   We wait on commit, if told to.
5156  *
5157  * - Within iput_final() -> write_inode_now()
5158  *   We wait on commit, if told to.
5159  *
5160  * In all cases it is actually safe for us to return without doing anything,
5161  * because the inode has been copied into a raw inode buffer in
5162  * ext4_mark_inode_dirty().  This is a correctness thing for WB_SYNC_ALL
5163  * writeback.
5164  *
5165  * Note that we are absolutely dependent upon all inode dirtiers doing the
5166  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5167  * which we are interested.
5168  *
5169  * It would be a bug for them to not do this.  The code:
5170  *
5171  *	mark_inode_dirty(inode)
5172  *	stuff();
5173  *	inode->i_size = expr;
5174  *
5175  * is in error because write_inode() could occur while `stuff()' is running,
5176  * and the new i_size will be lost.  Plus the inode will no longer be on the
5177  * superblock's dirty inode list.
5178  */
ext4_write_inode(struct inode * inode,struct writeback_control * wbc)5179 int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
5180 {
5181 	int err;
5182 
5183 	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
5184 		return 0;
5185 
5186 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
5187 		return -EIO;
5188 
5189 	if (EXT4_SB(inode->i_sb)->s_journal) {
5190 		if (ext4_journal_current_handle()) {
5191 			ext4_debug("called recursively, non-PF_MEMALLOC!\n");
5192 			dump_stack();
5193 			return -EIO;
5194 		}
5195 
5196 		/*
5197 		 * No need to force transaction in WB_SYNC_NONE mode. Also
5198 		 * ext4_sync_fs() will force the commit after everything is
5199 		 * written.
5200 		 */
5201 		if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
5202 			return 0;
5203 
5204 		err = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
5205 						EXT4_I(inode)->i_sync_tid);
5206 	} else {
5207 		struct ext4_iloc iloc;
5208 
5209 		err = __ext4_get_inode_loc_noinmem(inode, &iloc);
5210 		if (err)
5211 			return err;
5212 		/*
5213 		 * sync(2) will flush the whole buffer cache. No need to do
5214 		 * it here separately for each inode.
5215 		 */
5216 		if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
5217 			sync_dirty_buffer(iloc.bh);
5218 		if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) {
5219 			ext4_error_inode_block(inode, iloc.bh->b_blocknr, EIO,
5220 					       "IO error syncing inode");
5221 			err = -EIO;
5222 		}
5223 		brelse(iloc.bh);
5224 	}
5225 	return err;
5226 }
5227 
5228 /*
5229  * In data=journal mode ext4_journalled_invalidate_folio() may fail to invalidate
5230  * buffers that are attached to a folio straddling i_size and are undergoing
5231  * commit. In that case we have to wait for commit to finish and try again.
5232  */
ext4_wait_for_tail_page_commit(struct inode * inode)5233 static void ext4_wait_for_tail_page_commit(struct inode *inode)
5234 {
5235 	unsigned offset;
5236 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
5237 	tid_t commit_tid = 0;
5238 	int ret;
5239 
5240 	offset = inode->i_size & (PAGE_SIZE - 1);
5241 	/*
5242 	 * If the folio is fully truncated, we don't need to wait for any commit
5243 	 * (and we even should not as __ext4_journalled_invalidate_folio() may
5244 	 * strip all buffers from the folio but keep the folio dirty which can then
5245 	 * confuse e.g. concurrent ext4_writepages() seeing dirty folio without
5246 	 * buffers). Also we don't need to wait for any commit if all buffers in
5247 	 * the folio remain valid. This is most beneficial for the common case of
5248 	 * blocksize == PAGESIZE.
5249 	 */
5250 	if (!offset || offset > (PAGE_SIZE - i_blocksize(inode)))
5251 		return;
5252 	while (1) {
5253 		struct folio *folio = filemap_lock_folio(inode->i_mapping,
5254 				      inode->i_size >> PAGE_SHIFT);
5255 		if (IS_ERR(folio))
5256 			return;
5257 		ret = __ext4_journalled_invalidate_folio(folio, offset,
5258 						folio_size(folio) - offset);
5259 		folio_unlock(folio);
5260 		folio_put(folio);
5261 		if (ret != -EBUSY)
5262 			return;
5263 		commit_tid = 0;
5264 		read_lock(&journal->j_state_lock);
5265 		if (journal->j_committing_transaction)
5266 			commit_tid = journal->j_committing_transaction->t_tid;
5267 		read_unlock(&journal->j_state_lock);
5268 		if (commit_tid)
5269 			jbd2_log_wait_commit(journal, commit_tid);
5270 	}
5271 }
5272 
5273 /*
5274  * ext4_setattr()
5275  *
5276  * Called from notify_change.
5277  *
5278  * We want to trap VFS attempts to truncate the file as soon as
5279  * possible.  In particular, we want to make sure that when the VFS
5280  * shrinks i_size, we put the inode on the orphan list and modify
5281  * i_disksize immediately, so that during the subsequent flushing of
5282  * dirty pages and freeing of disk blocks, we can guarantee that any
5283  * commit will leave the blocks being flushed in an unused state on
5284  * disk.  (On recovery, the inode will get truncated and the blocks will
5285  * be freed, so we have a strong guarantee that no future commit will
5286  * leave these blocks visible to the user.)
5287  *
5288  * Another thing we have to assure is that if we are in ordered mode
5289  * and inode is still attached to the committing transaction, we must
5290  * we start writeout of all the dirty pages which are being truncated.
5291  * This way we are sure that all the data written in the previous
5292  * transaction are already on disk (truncate waits for pages under
5293  * writeback).
5294  *
5295  * Called with inode->i_rwsem down.
5296  */
ext4_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)5297 int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
5298 		 struct iattr *attr)
5299 {
5300 	struct inode *inode = d_inode(dentry);
5301 	int error, rc = 0;
5302 	int orphan = 0;
5303 	const unsigned int ia_valid = attr->ia_valid;
5304 	bool inc_ivers = true;
5305 
5306 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
5307 		return -EIO;
5308 
5309 	if (unlikely(IS_IMMUTABLE(inode)))
5310 		return -EPERM;
5311 
5312 	if (unlikely(IS_APPEND(inode) &&
5313 		     (ia_valid & (ATTR_MODE | ATTR_UID |
5314 				  ATTR_GID | ATTR_TIMES_SET))))
5315 		return -EPERM;
5316 
5317 	error = setattr_prepare(idmap, dentry, attr);
5318 	if (error)
5319 		return error;
5320 
5321 	error = fscrypt_prepare_setattr(dentry, attr);
5322 	if (error)
5323 		return error;
5324 
5325 	error = fsverity_prepare_setattr(dentry, attr);
5326 	if (error)
5327 		return error;
5328 
5329 	if (is_quota_modification(idmap, inode, attr)) {
5330 		error = dquot_initialize(inode);
5331 		if (error)
5332 			return error;
5333 	}
5334 
5335 	if (i_uid_needs_update(idmap, attr, inode) ||
5336 	    i_gid_needs_update(idmap, attr, inode)) {
5337 		handle_t *handle;
5338 
5339 		/* (user+group)*(old+new) structure, inode write (sb,
5340 		 * inode block, ? - but truncate inode update has it) */
5341 		handle = ext4_journal_start(inode, EXT4_HT_QUOTA,
5342 			(EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb) +
5343 			 EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)) + 3);
5344 		if (IS_ERR(handle)) {
5345 			error = PTR_ERR(handle);
5346 			goto err_out;
5347 		}
5348 
5349 		/* dquot_transfer() calls back ext4_get_inode_usage() which
5350 		 * counts xattr inode references.
5351 		 */
5352 		down_read(&EXT4_I(inode)->xattr_sem);
5353 		error = dquot_transfer(idmap, inode, attr);
5354 		up_read(&EXT4_I(inode)->xattr_sem);
5355 
5356 		if (error) {
5357 			ext4_journal_stop(handle);
5358 			return error;
5359 		}
5360 		/* Update corresponding info in inode so that everything is in
5361 		 * one transaction */
5362 		i_uid_update(idmap, attr, inode);
5363 		i_gid_update(idmap, attr, inode);
5364 		error = ext4_mark_inode_dirty(handle, inode);
5365 		ext4_journal_stop(handle);
5366 		if (unlikely(error)) {
5367 			return error;
5368 		}
5369 	}
5370 
5371 	if (attr->ia_valid & ATTR_SIZE) {
5372 		handle_t *handle;
5373 		loff_t oldsize = inode->i_size;
5374 		loff_t old_disksize;
5375 		int shrink = (attr->ia_size < inode->i_size);
5376 
5377 		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
5378 			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5379 
5380 			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5381 				return -EFBIG;
5382 			}
5383 		}
5384 		if (!S_ISREG(inode->i_mode)) {
5385 			return -EINVAL;
5386 		}
5387 
5388 		if (attr->ia_size == inode->i_size)
5389 			inc_ivers = false;
5390 
5391 		if (shrink) {
5392 			if (ext4_should_order_data(inode)) {
5393 				error = ext4_begin_ordered_truncate(inode,
5394 							    attr->ia_size);
5395 				if (error)
5396 					goto err_out;
5397 			}
5398 			/*
5399 			 * Blocks are going to be removed from the inode. Wait
5400 			 * for dio in flight.
5401 			 */
5402 			inode_dio_wait(inode);
5403 		}
5404 
5405 		filemap_invalidate_lock(inode->i_mapping);
5406 
5407 		rc = ext4_break_layouts(inode);
5408 		if (rc) {
5409 			filemap_invalidate_unlock(inode->i_mapping);
5410 			goto err_out;
5411 		}
5412 
5413 		if (attr->ia_size != inode->i_size) {
5414 			handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
5415 			if (IS_ERR(handle)) {
5416 				error = PTR_ERR(handle);
5417 				goto out_mmap_sem;
5418 			}
5419 			if (ext4_handle_valid(handle) && shrink) {
5420 				error = ext4_orphan_add(handle, inode);
5421 				orphan = 1;
5422 			}
5423 			/*
5424 			 * Update c/mtime on truncate up, ext4_truncate() will
5425 			 * update c/mtime in shrink case below
5426 			 */
5427 			if (!shrink)
5428 				inode->i_mtime = inode_set_ctime_current(inode);
5429 
5430 			if (shrink)
5431 				ext4_fc_track_range(handle, inode,
5432 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5433 					inode->i_sb->s_blocksize_bits,
5434 					EXT_MAX_BLOCKS - 1);
5435 			else
5436 				ext4_fc_track_range(
5437 					handle, inode,
5438 					(oldsize > 0 ? oldsize - 1 : oldsize) >>
5439 					inode->i_sb->s_blocksize_bits,
5440 					(attr->ia_size > 0 ? attr->ia_size - 1 : 0) >>
5441 					inode->i_sb->s_blocksize_bits);
5442 
5443 			down_write(&EXT4_I(inode)->i_data_sem);
5444 			old_disksize = EXT4_I(inode)->i_disksize;
5445 			EXT4_I(inode)->i_disksize = attr->ia_size;
5446 			rc = ext4_mark_inode_dirty(handle, inode);
5447 			if (!error)
5448 				error = rc;
5449 			/*
5450 			 * We have to update i_size under i_data_sem together
5451 			 * with i_disksize to avoid races with writeback code
5452 			 * running ext4_wb_update_i_disksize().
5453 			 */
5454 			if (!error)
5455 				i_size_write(inode, attr->ia_size);
5456 			else
5457 				EXT4_I(inode)->i_disksize = old_disksize;
5458 			up_write(&EXT4_I(inode)->i_data_sem);
5459 			ext4_journal_stop(handle);
5460 			if (error)
5461 				goto out_mmap_sem;
5462 			if (!shrink) {
5463 				pagecache_isize_extended(inode, oldsize,
5464 							 inode->i_size);
5465 			} else if (ext4_should_journal_data(inode)) {
5466 				ext4_wait_for_tail_page_commit(inode);
5467 			}
5468 		}
5469 
5470 		/*
5471 		 * Truncate pagecache after we've waited for commit
5472 		 * in data=journal mode to make pages freeable.
5473 		 */
5474 		truncate_pagecache(inode, inode->i_size);
5475 		/*
5476 		 * Call ext4_truncate() even if i_size didn't change to
5477 		 * truncate possible preallocated blocks.
5478 		 */
5479 		if (attr->ia_size <= oldsize) {
5480 			rc = ext4_truncate(inode);
5481 			if (rc)
5482 				error = rc;
5483 		}
5484 out_mmap_sem:
5485 		filemap_invalidate_unlock(inode->i_mapping);
5486 	}
5487 
5488 	if (!error) {
5489 		if (inc_ivers)
5490 			inode_inc_iversion(inode);
5491 		setattr_copy(idmap, inode, attr);
5492 		mark_inode_dirty(inode);
5493 	}
5494 
5495 	/*
5496 	 * If the call to ext4_truncate failed to get a transaction handle at
5497 	 * all, we need to clean up the in-core orphan list manually.
5498 	 */
5499 	if (orphan && inode->i_nlink)
5500 		ext4_orphan_del(NULL, inode);
5501 
5502 	if (!error && (ia_valid & ATTR_MODE))
5503 		rc = posix_acl_chmod(idmap, dentry, inode->i_mode);
5504 
5505 err_out:
5506 	if  (error)
5507 		ext4_std_error(inode->i_sb, error);
5508 	if (!error)
5509 		error = rc;
5510 	return error;
5511 }
5512 
ext4_dio_alignment(struct inode * inode)5513 u32 ext4_dio_alignment(struct inode *inode)
5514 {
5515 	if (fsverity_active(inode))
5516 		return 0;
5517 	if (ext4_should_journal_data(inode))
5518 		return 0;
5519 	if (ext4_has_inline_data(inode))
5520 		return 0;
5521 	if (IS_ENCRYPTED(inode)) {
5522 		if (!fscrypt_dio_supported(inode))
5523 			return 0;
5524 		return i_blocksize(inode);
5525 	}
5526 	return 1; /* use the iomap defaults */
5527 }
5528 
ext4_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)5529 int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
5530 		 struct kstat *stat, u32 request_mask, unsigned int query_flags)
5531 {
5532 	struct inode *inode = d_inode(path->dentry);
5533 	struct ext4_inode *raw_inode;
5534 	struct ext4_inode_info *ei = EXT4_I(inode);
5535 	unsigned int flags;
5536 
5537 	if ((request_mask & STATX_BTIME) &&
5538 	    EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
5539 		stat->result_mask |= STATX_BTIME;
5540 		stat->btime.tv_sec = ei->i_crtime.tv_sec;
5541 		stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
5542 	}
5543 
5544 	/*
5545 	 * Return the DIO alignment restrictions if requested.  We only return
5546 	 * this information when requested, since on encrypted files it might
5547 	 * take a fair bit of work to get if the file wasn't opened recently.
5548 	 */
5549 	if ((request_mask & STATX_DIOALIGN) && S_ISREG(inode->i_mode)) {
5550 		u32 dio_align = ext4_dio_alignment(inode);
5551 
5552 		stat->result_mask |= STATX_DIOALIGN;
5553 		if (dio_align == 1) {
5554 			struct block_device *bdev = inode->i_sb->s_bdev;
5555 
5556 			/* iomap defaults */
5557 			stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
5558 			stat->dio_offset_align = bdev_logical_block_size(bdev);
5559 		} else {
5560 			stat->dio_mem_align = dio_align;
5561 			stat->dio_offset_align = dio_align;
5562 		}
5563 	}
5564 
5565 	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
5566 	if (flags & EXT4_APPEND_FL)
5567 		stat->attributes |= STATX_ATTR_APPEND;
5568 	if (flags & EXT4_COMPR_FL)
5569 		stat->attributes |= STATX_ATTR_COMPRESSED;
5570 	if (flags & EXT4_ENCRYPT_FL)
5571 		stat->attributes |= STATX_ATTR_ENCRYPTED;
5572 	if (flags & EXT4_IMMUTABLE_FL)
5573 		stat->attributes |= STATX_ATTR_IMMUTABLE;
5574 	if (flags & EXT4_NODUMP_FL)
5575 		stat->attributes |= STATX_ATTR_NODUMP;
5576 	if (flags & EXT4_VERITY_FL)
5577 		stat->attributes |= STATX_ATTR_VERITY;
5578 
5579 	stat->attributes_mask |= (STATX_ATTR_APPEND |
5580 				  STATX_ATTR_COMPRESSED |
5581 				  STATX_ATTR_ENCRYPTED |
5582 				  STATX_ATTR_IMMUTABLE |
5583 				  STATX_ATTR_NODUMP |
5584 				  STATX_ATTR_VERITY);
5585 
5586 	generic_fillattr(idmap, request_mask, inode, stat);
5587 	return 0;
5588 }
5589 
ext4_file_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)5590 int ext4_file_getattr(struct mnt_idmap *idmap,
5591 		      const struct path *path, struct kstat *stat,
5592 		      u32 request_mask, unsigned int query_flags)
5593 {
5594 	struct inode *inode = d_inode(path->dentry);
5595 	u64 delalloc_blocks;
5596 
5597 	ext4_getattr(idmap, path, stat, request_mask, query_flags);
5598 
5599 	/*
5600 	 * If there is inline data in the inode, the inode will normally not
5601 	 * have data blocks allocated (it may have an external xattr block).
5602 	 * Report at least one sector for such files, so tools like tar, rsync,
5603 	 * others don't incorrectly think the file is completely sparse.
5604 	 */
5605 	if (unlikely(ext4_has_inline_data(inode)))
5606 		stat->blocks += (stat->size + 511) >> 9;
5607 
5608 	/*
5609 	 * We can't update i_blocks if the block allocation is delayed
5610 	 * otherwise in the case of system crash before the real block
5611 	 * allocation is done, we will have i_blocks inconsistent with
5612 	 * on-disk file blocks.
5613 	 * We always keep i_blocks updated together with real
5614 	 * allocation. But to not confuse with user, stat
5615 	 * will return the blocks that include the delayed allocation
5616 	 * blocks for this file.
5617 	 */
5618 	delalloc_blocks = EXT4_C2B(EXT4_SB(inode->i_sb),
5619 				   EXT4_I(inode)->i_reserved_data_blocks);
5620 	stat->blocks += delalloc_blocks << (inode->i_sb->s_blocksize_bits - 9);
5621 	return 0;
5622 }
5623 
ext4_index_trans_blocks(struct inode * inode,int lblocks,int pextents)5624 static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
5625 				   int pextents)
5626 {
5627 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
5628 		return ext4_ind_trans_blocks(inode, lblocks);
5629 	return ext4_ext_index_trans_blocks(inode, pextents);
5630 }
5631 
5632 /*
5633  * Account for index blocks, block groups bitmaps and block group
5634  * descriptor blocks if modify datablocks and index blocks
5635  * worse case, the indexs blocks spread over different block groups
5636  *
5637  * If datablocks are discontiguous, they are possible to spread over
5638  * different block groups too. If they are contiguous, with flexbg,
5639  * they could still across block group boundary.
5640  *
5641  * Also account for superblock, inode, quota and xattr blocks
5642  */
ext4_meta_trans_blocks(struct inode * inode,int lblocks,int pextents)5643 static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
5644 				  int pextents)
5645 {
5646 	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5647 	int gdpblocks;
5648 	int idxblocks;
5649 	int ret;
5650 
5651 	/*
5652 	 * How many index blocks need to touch to map @lblocks logical blocks
5653 	 * to @pextents physical extents?
5654 	 */
5655 	idxblocks = ext4_index_trans_blocks(inode, lblocks, pextents);
5656 
5657 	ret = idxblocks;
5658 
5659 	/*
5660 	 * Now let's see how many group bitmaps and group descriptors need
5661 	 * to account
5662 	 */
5663 	groups = idxblocks + pextents;
5664 	gdpblocks = groups;
5665 	if (groups > ngroups)
5666 		groups = ngroups;
5667 	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5668 		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5669 
5670 	/* bitmaps and block group descriptor blocks */
5671 	ret += groups + gdpblocks;
5672 
5673 	/* Blocks for super block, inode, quota and xattr blocks */
5674 	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5675 
5676 	return ret;
5677 }
5678 
5679 /*
5680  * Calculate the total number of credits to reserve to fit
5681  * the modification of a single pages into a single transaction,
5682  * which may include multiple chunks of block allocations.
5683  *
5684  * This could be called via ext4_write_begin()
5685  *
5686  * We need to consider the worse case, when
5687  * one new block per extent.
5688  */
ext4_writepage_trans_blocks(struct inode * inode)5689 int ext4_writepage_trans_blocks(struct inode *inode)
5690 {
5691 	int bpp = ext4_journal_blocks_per_page(inode);
5692 	int ret;
5693 
5694 	ret = ext4_meta_trans_blocks(inode, bpp, bpp);
5695 
5696 	/* Account for data blocks for journalled mode */
5697 	if (ext4_should_journal_data(inode))
5698 		ret += bpp;
5699 	return ret;
5700 }
5701 
5702 /*
5703  * Calculate the journal credits for a chunk of data modification.
5704  *
5705  * This is called from DIO, fallocate or whoever calling
5706  * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks.
5707  *
5708  * journal buffers for data blocks are not included here, as DIO
5709  * and fallocate do no need to journal data buffers.
5710  */
ext4_chunk_trans_blocks(struct inode * inode,int nrblocks)5711 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5712 {
5713 	return ext4_meta_trans_blocks(inode, nrblocks, 1);
5714 }
5715 
5716 /*
5717  * The caller must have previously called ext4_reserve_inode_write().
5718  * Give this, we know that the caller already has write access to iloc->bh.
5719  */
ext4_mark_iloc_dirty(handle_t * handle,struct inode * inode,struct ext4_iloc * iloc)5720 int ext4_mark_iloc_dirty(handle_t *handle,
5721 			 struct inode *inode, struct ext4_iloc *iloc)
5722 {
5723 	int err = 0;
5724 
5725 	if (unlikely(ext4_forced_shutdown(inode->i_sb))) {
5726 		put_bh(iloc->bh);
5727 		return -EIO;
5728 	}
5729 	ext4_fc_track_inode(handle, inode);
5730 
5731 	/* the do_update_inode consumes one bh->b_count */
5732 	get_bh(iloc->bh);
5733 
5734 	/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5735 	err = ext4_do_update_inode(handle, inode, iloc);
5736 	put_bh(iloc->bh);
5737 	return err;
5738 }
5739 
5740 /*
5741  * On success, We end up with an outstanding reference count against
5742  * iloc->bh.  This _must_ be cleaned up later.
5743  */
5744 
5745 int
ext4_reserve_inode_write(handle_t * handle,struct inode * inode,struct ext4_iloc * iloc)5746 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5747 			 struct ext4_iloc *iloc)
5748 {
5749 	int err;
5750 
5751 	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
5752 		return -EIO;
5753 
5754 	err = ext4_get_inode_loc(inode, iloc);
5755 	if (!err) {
5756 		BUFFER_TRACE(iloc->bh, "get_write_access");
5757 		err = ext4_journal_get_write_access(handle, inode->i_sb,
5758 						    iloc->bh, EXT4_JTR_NONE);
5759 		if (err) {
5760 			brelse(iloc->bh);
5761 			iloc->bh = NULL;
5762 		}
5763 	}
5764 	ext4_std_error(inode->i_sb, err);
5765 	return err;
5766 }
5767 
__ext4_expand_extra_isize(struct inode * inode,unsigned int new_extra_isize,struct ext4_iloc * iloc,handle_t * handle,int * no_expand)5768 static int __ext4_expand_extra_isize(struct inode *inode,
5769 				     unsigned int new_extra_isize,
5770 				     struct ext4_iloc *iloc,
5771 				     handle_t *handle, int *no_expand)
5772 {
5773 	struct ext4_inode *raw_inode;
5774 	struct ext4_xattr_ibody_header *header;
5775 	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
5776 	struct ext4_inode_info *ei = EXT4_I(inode);
5777 	int error;
5778 
5779 	/* this was checked at iget time, but double check for good measure */
5780 	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
5781 	    (ei->i_extra_isize & 3)) {
5782 		EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)",
5783 				 ei->i_extra_isize,
5784 				 EXT4_INODE_SIZE(inode->i_sb));
5785 		return -EFSCORRUPTED;
5786 	}
5787 	if ((new_extra_isize < ei->i_extra_isize) ||
5788 	    (new_extra_isize < 4) ||
5789 	    (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE))
5790 		return -EINVAL;	/* Should never happen */
5791 
5792 	raw_inode = ext4_raw_inode(iloc);
5793 
5794 	header = IHDR(inode, raw_inode);
5795 
5796 	/* No extended attributes present */
5797 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) ||
5798 	    header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5799 		memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
5800 		       EXT4_I(inode)->i_extra_isize, 0,
5801 		       new_extra_isize - EXT4_I(inode)->i_extra_isize);
5802 		EXT4_I(inode)->i_extra_isize = new_extra_isize;
5803 		return 0;
5804 	}
5805 
5806 	/*
5807 	 * We may need to allocate external xattr block so we need quotas
5808 	 * initialized. Here we can be called with various locks held so we
5809 	 * cannot affort to initialize quotas ourselves. So just bail.
5810 	 */
5811 	if (dquot_initialize_needed(inode))
5812 		return -EAGAIN;
5813 
5814 	/* try to expand with EAs present */
5815 	error = ext4_expand_extra_isize_ea(inode, new_extra_isize,
5816 					   raw_inode, handle);
5817 	if (error) {
5818 		/*
5819 		 * Inode size expansion failed; don't try again
5820 		 */
5821 		*no_expand = 1;
5822 	}
5823 
5824 	return error;
5825 }
5826 
5827 /*
5828  * Expand an inode by new_extra_isize bytes.
5829  * Returns 0 on success or negative error number on failure.
5830  */
ext4_try_to_expand_extra_isize(struct inode * inode,unsigned int new_extra_isize,struct ext4_iloc iloc,handle_t * handle)5831 static int ext4_try_to_expand_extra_isize(struct inode *inode,
5832 					  unsigned int new_extra_isize,
5833 					  struct ext4_iloc iloc,
5834 					  handle_t *handle)
5835 {
5836 	int no_expand;
5837 	int error;
5838 
5839 	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND))
5840 		return -EOVERFLOW;
5841 
5842 	/*
5843 	 * In nojournal mode, we can immediately attempt to expand
5844 	 * the inode.  When journaled, we first need to obtain extra
5845 	 * buffer credits since we may write into the EA block
5846 	 * with this same handle. If journal_extend fails, then it will
5847 	 * only result in a minor loss of functionality for that inode.
5848 	 * If this is felt to be critical, then e2fsck should be run to
5849 	 * force a large enough s_min_extra_isize.
5850 	 */
5851 	if (ext4_journal_extend(handle,
5852 				EXT4_DATA_TRANS_BLOCKS(inode->i_sb), 0) != 0)
5853 		return -ENOSPC;
5854 
5855 	if (ext4_write_trylock_xattr(inode, &no_expand) == 0)
5856 		return -EBUSY;
5857 
5858 	error = __ext4_expand_extra_isize(inode, new_extra_isize, &iloc,
5859 					  handle, &no_expand);
5860 	ext4_write_unlock_xattr(inode, &no_expand);
5861 
5862 	return error;
5863 }
5864 
ext4_expand_extra_isize(struct inode * inode,unsigned int new_extra_isize,struct ext4_iloc * iloc)5865 int ext4_expand_extra_isize(struct inode *inode,
5866 			    unsigned int new_extra_isize,
5867 			    struct ext4_iloc *iloc)
5868 {
5869 	handle_t *handle;
5870 	int no_expand;
5871 	int error, rc;
5872 
5873 	if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
5874 		brelse(iloc->bh);
5875 		return -EOVERFLOW;
5876 	}
5877 
5878 	handle = ext4_journal_start(inode, EXT4_HT_INODE,
5879 				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
5880 	if (IS_ERR(handle)) {
5881 		error = PTR_ERR(handle);
5882 		brelse(iloc->bh);
5883 		return error;
5884 	}
5885 
5886 	ext4_write_lock_xattr(inode, &no_expand);
5887 
5888 	BUFFER_TRACE(iloc->bh, "get_write_access");
5889 	error = ext4_journal_get_write_access(handle, inode->i_sb, iloc->bh,
5890 					      EXT4_JTR_NONE);
5891 	if (error) {
5892 		brelse(iloc->bh);
5893 		goto out_unlock;
5894 	}
5895 
5896 	error = __ext4_expand_extra_isize(inode, new_extra_isize, iloc,
5897 					  handle, &no_expand);
5898 
5899 	rc = ext4_mark_iloc_dirty(handle, inode, iloc);
5900 	if (!error)
5901 		error = rc;
5902 
5903 out_unlock:
5904 	ext4_write_unlock_xattr(inode, &no_expand);
5905 	ext4_journal_stop(handle);
5906 	return error;
5907 }
5908 
5909 /*
5910  * What we do here is to mark the in-core inode as clean with respect to inode
5911  * dirtiness (it may still be data-dirty).
5912  * This means that the in-core inode may be reaped by prune_icache
5913  * without having to perform any I/O.  This is a very good thing,
5914  * because *any* task may call prune_icache - even ones which
5915  * have a transaction open against a different journal.
5916  *
5917  * Is this cheating?  Not really.  Sure, we haven't written the
5918  * inode out, but prune_icache isn't a user-visible syncing function.
5919  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5920  * we start and wait on commits.
5921  */
__ext4_mark_inode_dirty(handle_t * handle,struct inode * inode,const char * func,unsigned int line)5922 int __ext4_mark_inode_dirty(handle_t *handle, struct inode *inode,
5923 				const char *func, unsigned int line)
5924 {
5925 	struct ext4_iloc iloc;
5926 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5927 	int err;
5928 
5929 	might_sleep();
5930 	trace_ext4_mark_inode_dirty(inode, _RET_IP_);
5931 	err = ext4_reserve_inode_write(handle, inode, &iloc);
5932 	if (err)
5933 		goto out;
5934 
5935 	if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize)
5936 		ext4_try_to_expand_extra_isize(inode, sbi->s_want_extra_isize,
5937 					       iloc, handle);
5938 
5939 	err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5940 out:
5941 	if (unlikely(err))
5942 		ext4_error_inode_err(inode, func, line, 0, err,
5943 					"mark_inode_dirty error");
5944 	return err;
5945 }
5946 
5947 /*
5948  * ext4_dirty_inode() is called from __mark_inode_dirty()
5949  *
5950  * We're really interested in the case where a file is being extended.
5951  * i_size has been changed by generic_commit_write() and we thus need
5952  * to include the updated inode in the current transaction.
5953  *
5954  * Also, dquot_alloc_block() will always dirty the inode when blocks
5955  * are allocated to the file.
5956  *
5957  * If the inode is marked synchronous, we don't honour that here - doing
5958  * so would cause a commit on atime updates, which we don't bother doing.
5959  * We handle synchronous inodes at the highest possible level.
5960  */
ext4_dirty_inode(struct inode * inode,int flags)5961 void ext4_dirty_inode(struct inode *inode, int flags)
5962 {
5963 	handle_t *handle;
5964 
5965 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
5966 	if (IS_ERR(handle))
5967 		return;
5968 	ext4_mark_inode_dirty(handle, inode);
5969 	ext4_journal_stop(handle);
5970 }
5971 
ext4_change_inode_journal_flag(struct inode * inode,int val)5972 int ext4_change_inode_journal_flag(struct inode *inode, int val)
5973 {
5974 	journal_t *journal;
5975 	handle_t *handle;
5976 	int err;
5977 	int alloc_ctx;
5978 
5979 	/*
5980 	 * We have to be very careful here: changing a data block's
5981 	 * journaling status dynamically is dangerous.  If we write a
5982 	 * data block to the journal, change the status and then delete
5983 	 * that block, we risk forgetting to revoke the old log record
5984 	 * from the journal and so a subsequent replay can corrupt data.
5985 	 * So, first we make sure that the journal is empty and that
5986 	 * nobody is changing anything.
5987 	 */
5988 
5989 	journal = EXT4_JOURNAL(inode);
5990 	if (!journal)
5991 		return 0;
5992 	if (is_journal_aborted(journal))
5993 		return -EROFS;
5994 
5995 	/* Wait for all existing dio workers */
5996 	inode_dio_wait(inode);
5997 
5998 	/*
5999 	 * Before flushing the journal and switching inode's aops, we have
6000 	 * to flush all dirty data the inode has. There can be outstanding
6001 	 * delayed allocations, there can be unwritten extents created by
6002 	 * fallocate or buffered writes in dioread_nolock mode covered by
6003 	 * dirty data which can be converted only after flushing the dirty
6004 	 * data (and journalled aops don't know how to handle these cases).
6005 	 */
6006 	if (val) {
6007 		filemap_invalidate_lock(inode->i_mapping);
6008 		err = filemap_write_and_wait(inode->i_mapping);
6009 		if (err < 0) {
6010 			filemap_invalidate_unlock(inode->i_mapping);
6011 			return err;
6012 		}
6013 	}
6014 
6015 	alloc_ctx = ext4_writepages_down_write(inode->i_sb);
6016 	jbd2_journal_lock_updates(journal);
6017 
6018 	/*
6019 	 * OK, there are no updates running now, and all cached data is
6020 	 * synced to disk.  We are now in a completely consistent state
6021 	 * which doesn't have anything in the journal, and we know that
6022 	 * no filesystem updates are running, so it is safe to modify
6023 	 * the inode's in-core data-journaling state flag now.
6024 	 */
6025 
6026 	if (val)
6027 		ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6028 	else {
6029 		err = jbd2_journal_flush(journal, 0);
6030 		if (err < 0) {
6031 			jbd2_journal_unlock_updates(journal);
6032 			ext4_writepages_up_write(inode->i_sb, alloc_ctx);
6033 			return err;
6034 		}
6035 		ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA);
6036 	}
6037 	ext4_set_aops(inode);
6038 
6039 	jbd2_journal_unlock_updates(journal);
6040 	ext4_writepages_up_write(inode->i_sb, alloc_ctx);
6041 
6042 	if (val)
6043 		filemap_invalidate_unlock(inode->i_mapping);
6044 
6045 	/* Finally we can mark the inode as dirty. */
6046 
6047 	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
6048 	if (IS_ERR(handle))
6049 		return PTR_ERR(handle);
6050 
6051 	ext4_fc_mark_ineligible(inode->i_sb,
6052 		EXT4_FC_REASON_JOURNAL_FLAG_CHANGE, handle);
6053 	err = ext4_mark_inode_dirty(handle, inode);
6054 	ext4_handle_sync(handle);
6055 	ext4_journal_stop(handle);
6056 	ext4_std_error(inode->i_sb, err);
6057 
6058 	return err;
6059 }
6060 
ext4_bh_unmapped(handle_t * handle,struct inode * inode,struct buffer_head * bh)6061 static int ext4_bh_unmapped(handle_t *handle, struct inode *inode,
6062 			    struct buffer_head *bh)
6063 {
6064 	return !buffer_mapped(bh);
6065 }
6066 
ext4_page_mkwrite(struct vm_fault * vmf)6067 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
6068 {
6069 	struct vm_area_struct *vma = vmf->vma;
6070 	struct folio *folio = page_folio(vmf->page);
6071 	loff_t size;
6072 	unsigned long len;
6073 	int err;
6074 	vm_fault_t ret;
6075 	struct file *file = vma->vm_file;
6076 	struct inode *inode = file_inode(file);
6077 	struct address_space *mapping = inode->i_mapping;
6078 	handle_t *handle;
6079 	get_block_t *get_block;
6080 	int retries = 0;
6081 
6082 	if (unlikely(IS_IMMUTABLE(inode)))
6083 		return VM_FAULT_SIGBUS;
6084 
6085 	sb_start_pagefault(inode->i_sb);
6086 	file_update_time(vma->vm_file);
6087 
6088 	filemap_invalidate_lock_shared(mapping);
6089 
6090 	err = ext4_convert_inline_data(inode);
6091 	if (err)
6092 		goto out_ret;
6093 
6094 	/*
6095 	 * On data journalling we skip straight to the transaction handle:
6096 	 * there's no delalloc; page truncated will be checked later; the
6097 	 * early return w/ all buffers mapped (calculates size/len) can't
6098 	 * be used; and there's no dioread_nolock, so only ext4_get_block.
6099 	 */
6100 	if (ext4_should_journal_data(inode))
6101 		goto retry_alloc;
6102 
6103 	/* Delalloc case is easy... */
6104 	if (test_opt(inode->i_sb, DELALLOC) &&
6105 	    !ext4_nonda_switch(inode->i_sb)) {
6106 		do {
6107 			err = block_page_mkwrite(vma, vmf,
6108 						   ext4_da_get_block_prep);
6109 		} while (err == -ENOSPC &&
6110 		       ext4_should_retry_alloc(inode->i_sb, &retries));
6111 		goto out_ret;
6112 	}
6113 
6114 	folio_lock(folio);
6115 	size = i_size_read(inode);
6116 	/* Page got truncated from under us? */
6117 	if (folio->mapping != mapping || folio_pos(folio) > size) {
6118 		folio_unlock(folio);
6119 		ret = VM_FAULT_NOPAGE;
6120 		goto out;
6121 	}
6122 
6123 	len = folio_size(folio);
6124 	if (folio_pos(folio) + len > size)
6125 		len = size - folio_pos(folio);
6126 	/*
6127 	 * Return if we have all the buffers mapped. This avoids the need to do
6128 	 * journal_start/journal_stop which can block and take a long time
6129 	 *
6130 	 * This cannot be done for data journalling, as we have to add the
6131 	 * inode to the transaction's list to writeprotect pages on commit.
6132 	 */
6133 	if (folio_buffers(folio)) {
6134 		if (!ext4_walk_page_buffers(NULL, inode, folio_buffers(folio),
6135 					    0, len, NULL,
6136 					    ext4_bh_unmapped)) {
6137 			/* Wait so that we don't change page under IO */
6138 			folio_wait_stable(folio);
6139 			ret = VM_FAULT_LOCKED;
6140 			goto out;
6141 		}
6142 	}
6143 	folio_unlock(folio);
6144 	/* OK, we need to fill the hole... */
6145 	if (ext4_should_dioread_nolock(inode))
6146 		get_block = ext4_get_block_unwritten;
6147 	else
6148 		get_block = ext4_get_block;
6149 retry_alloc:
6150 	handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
6151 				    ext4_writepage_trans_blocks(inode));
6152 	if (IS_ERR(handle)) {
6153 		ret = VM_FAULT_SIGBUS;
6154 		goto out;
6155 	}
6156 	/*
6157 	 * Data journalling can't use block_page_mkwrite() because it
6158 	 * will set_buffer_dirty() before do_journal_get_write_access()
6159 	 * thus might hit warning messages for dirty metadata buffers.
6160 	 */
6161 	if (!ext4_should_journal_data(inode)) {
6162 		err = block_page_mkwrite(vma, vmf, get_block);
6163 	} else {
6164 		folio_lock(folio);
6165 		size = i_size_read(inode);
6166 		/* Page got truncated from under us? */
6167 		if (folio->mapping != mapping || folio_pos(folio) > size) {
6168 			ret = VM_FAULT_NOPAGE;
6169 			goto out_error;
6170 		}
6171 
6172 		len = folio_size(folio);
6173 		if (folio_pos(folio) + len > size)
6174 			len = size - folio_pos(folio);
6175 
6176 		err = __block_write_begin(&folio->page, 0, len, ext4_get_block);
6177 		if (!err) {
6178 			ret = VM_FAULT_SIGBUS;
6179 			if (ext4_journal_folio_buffers(handle, folio, len))
6180 				goto out_error;
6181 		} else {
6182 			folio_unlock(folio);
6183 		}
6184 	}
6185 	ext4_journal_stop(handle);
6186 	if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
6187 		goto retry_alloc;
6188 out_ret:
6189 	ret = vmf_fs_error(err);
6190 out:
6191 	filemap_invalidate_unlock_shared(mapping);
6192 	sb_end_pagefault(inode->i_sb);
6193 	return ret;
6194 out_error:
6195 	folio_unlock(folio);
6196 	ext4_journal_stop(handle);
6197 	goto out;
6198 }
6199