1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3  * Copyright IBM Corporation, 2007
4  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
5  *
6  */
7 
8 #include <linux/slab.h>
9 #include "ext4_jbd2.h"
10 #include "ext4_extents.h"
11 
12 /*
13  * The contiguous blocks details which can be
14  * represented by a single extent
15  */
16 struct migrate_struct {
17 	ext4_lblk_t first_block, last_block, curr_block;
18 	ext4_fsblk_t first_pblock, last_pblock;
19 };
20 
finish_range(handle_t * handle,struct inode * inode,struct migrate_struct * lb)21 static int finish_range(handle_t *handle, struct inode *inode,
22 				struct migrate_struct *lb)
23 
24 {
25 	int retval = 0, needed;
26 	struct ext4_extent newext;
27 	struct ext4_ext_path *path;
28 	if (lb->first_pblock == 0)
29 		return 0;
30 
31 	/* Add the extent to temp inode*/
32 	newext.ee_block = cpu_to_le32(lb->first_block);
33 	newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
34 	ext4_ext_store_pblock(&newext, lb->first_pblock);
35 	/* Locking only for convenience since we are operating on temp inode */
36 	down_write(&EXT4_I(inode)->i_data_sem);
37 	path = ext4_find_extent(inode, lb->first_block, NULL, 0);
38 	if (IS_ERR(path)) {
39 		retval = PTR_ERR(path);
40 		path = NULL;
41 		goto err_out;
42 	}
43 
44 	/*
45 	 * Calculate the credit needed to inserting this extent
46 	 * Since we are doing this in loop we may accumulate extra
47 	 * credit. But below we try to not accumulate too much
48 	 * of them by restarting the journal.
49 	 */
50 	needed = ext4_ext_calc_credits_for_single_extent(inode,
51 		    lb->last_block - lb->first_block + 1, path);
52 
53 	retval = ext4_datasem_ensure_credits(handle, inode, needed, needed, 0);
54 	if (retval < 0)
55 		goto err_out;
56 	retval = ext4_ext_insert_extent(handle, inode, &path, &newext, 0);
57 err_out:
58 	up_write((&EXT4_I(inode)->i_data_sem));
59 	ext4_ext_drop_refs(path);
60 	kfree(path);
61 	lb->first_pblock = 0;
62 	return retval;
63 }
64 
update_extent_range(handle_t * handle,struct inode * inode,ext4_fsblk_t pblock,struct migrate_struct * lb)65 static int update_extent_range(handle_t *handle, struct inode *inode,
66 			       ext4_fsblk_t pblock, struct migrate_struct *lb)
67 {
68 	int retval;
69 	/*
70 	 * See if we can add on to the existing range (if it exists)
71 	 */
72 	if (lb->first_pblock &&
73 		(lb->last_pblock+1 == pblock) &&
74 		(lb->last_block+1 == lb->curr_block)) {
75 		lb->last_pblock = pblock;
76 		lb->last_block = lb->curr_block;
77 		lb->curr_block++;
78 		return 0;
79 	}
80 	/*
81 	 * Start a new range.
82 	 */
83 	retval = finish_range(handle, inode, lb);
84 	lb->first_pblock = lb->last_pblock = pblock;
85 	lb->first_block = lb->last_block = lb->curr_block;
86 	lb->curr_block++;
87 	return retval;
88 }
89 
update_ind_extent_range(handle_t * handle,struct inode * inode,ext4_fsblk_t pblock,struct migrate_struct * lb)90 static int update_ind_extent_range(handle_t *handle, struct inode *inode,
91 				   ext4_fsblk_t pblock,
92 				   struct migrate_struct *lb)
93 {
94 	struct buffer_head *bh;
95 	__le32 *i_data;
96 	int i, retval = 0;
97 	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
98 
99 	bh = ext4_sb_bread(inode->i_sb, pblock, 0);
100 	if (IS_ERR(bh))
101 		return PTR_ERR(bh);
102 
103 	i_data = (__le32 *)bh->b_data;
104 	for (i = 0; i < max_entries; i++) {
105 		if (i_data[i]) {
106 			retval = update_extent_range(handle, inode,
107 						le32_to_cpu(i_data[i]), lb);
108 			if (retval)
109 				break;
110 		} else {
111 			lb->curr_block++;
112 		}
113 	}
114 	put_bh(bh);
115 	return retval;
116 
117 }
118 
update_dind_extent_range(handle_t * handle,struct inode * inode,ext4_fsblk_t pblock,struct migrate_struct * lb)119 static int update_dind_extent_range(handle_t *handle, struct inode *inode,
120 				    ext4_fsblk_t pblock,
121 				    struct migrate_struct *lb)
122 {
123 	struct buffer_head *bh;
124 	__le32 *i_data;
125 	int i, retval = 0;
126 	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
127 
128 	bh = ext4_sb_bread(inode->i_sb, pblock, 0);
129 	if (IS_ERR(bh))
130 		return PTR_ERR(bh);
131 
132 	i_data = (__le32 *)bh->b_data;
133 	for (i = 0; i < max_entries; i++) {
134 		if (i_data[i]) {
135 			retval = update_ind_extent_range(handle, inode,
136 						le32_to_cpu(i_data[i]), lb);
137 			if (retval)
138 				break;
139 		} else {
140 			/* Only update the file block number */
141 			lb->curr_block += max_entries;
142 		}
143 	}
144 	put_bh(bh);
145 	return retval;
146 
147 }
148 
update_tind_extent_range(handle_t * handle,struct inode * inode,ext4_fsblk_t pblock,struct migrate_struct * lb)149 static int update_tind_extent_range(handle_t *handle, struct inode *inode,
150 				    ext4_fsblk_t pblock,
151 				    struct migrate_struct *lb)
152 {
153 	struct buffer_head *bh;
154 	__le32 *i_data;
155 	int i, retval = 0;
156 	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
157 
158 	bh = ext4_sb_bread(inode->i_sb, pblock, 0);
159 	if (IS_ERR(bh))
160 		return PTR_ERR(bh);
161 
162 	i_data = (__le32 *)bh->b_data;
163 	for (i = 0; i < max_entries; i++) {
164 		if (i_data[i]) {
165 			retval = update_dind_extent_range(handle, inode,
166 						le32_to_cpu(i_data[i]), lb);
167 			if (retval)
168 				break;
169 		} else {
170 			/* Only update the file block number */
171 			lb->curr_block += max_entries * max_entries;
172 		}
173 	}
174 	put_bh(bh);
175 	return retval;
176 
177 }
178 
free_dind_blocks(handle_t * handle,struct inode * inode,__le32 i_data)179 static int free_dind_blocks(handle_t *handle,
180 				struct inode *inode, __le32 i_data)
181 {
182 	int i;
183 	__le32 *tmp_idata;
184 	struct buffer_head *bh;
185 	struct super_block *sb = inode->i_sb;
186 	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
187 	int err;
188 
189 	bh = ext4_sb_bread(sb, le32_to_cpu(i_data), 0);
190 	if (IS_ERR(bh))
191 		return PTR_ERR(bh);
192 
193 	tmp_idata = (__le32 *)bh->b_data;
194 	for (i = 0; i < max_entries; i++) {
195 		if (tmp_idata[i]) {
196 			err = ext4_journal_ensure_credits(handle,
197 				EXT4_RESERVE_TRANS_BLOCKS,
198 				ext4_free_metadata_revoke_credits(sb, 1));
199 			if (err < 0) {
200 				put_bh(bh);
201 				return err;
202 			}
203 			ext4_free_blocks(handle, inode, NULL,
204 					 le32_to_cpu(tmp_idata[i]), 1,
205 					 EXT4_FREE_BLOCKS_METADATA |
206 					 EXT4_FREE_BLOCKS_FORGET);
207 		}
208 	}
209 	put_bh(bh);
210 	err = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
211 				ext4_free_metadata_revoke_credits(sb, 1));
212 	if (err < 0)
213 		return err;
214 	ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
215 			 EXT4_FREE_BLOCKS_METADATA |
216 			 EXT4_FREE_BLOCKS_FORGET);
217 	return 0;
218 }
219 
free_tind_blocks(handle_t * handle,struct inode * inode,__le32 i_data)220 static int free_tind_blocks(handle_t *handle,
221 				struct inode *inode, __le32 i_data)
222 {
223 	int i, retval = 0;
224 	__le32 *tmp_idata;
225 	struct buffer_head *bh;
226 	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
227 
228 	bh = ext4_sb_bread(inode->i_sb, le32_to_cpu(i_data), 0);
229 	if (IS_ERR(bh))
230 		return PTR_ERR(bh);
231 
232 	tmp_idata = (__le32 *)bh->b_data;
233 	for (i = 0; i < max_entries; i++) {
234 		if (tmp_idata[i]) {
235 			retval = free_dind_blocks(handle,
236 					inode, tmp_idata[i]);
237 			if (retval) {
238 				put_bh(bh);
239 				return retval;
240 			}
241 		}
242 	}
243 	put_bh(bh);
244 	retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
245 			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
246 	if (retval < 0)
247 		return retval;
248 	ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
249 			 EXT4_FREE_BLOCKS_METADATA |
250 			 EXT4_FREE_BLOCKS_FORGET);
251 	return 0;
252 }
253 
free_ind_block(handle_t * handle,struct inode * inode,__le32 * i_data)254 static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
255 {
256 	int retval;
257 
258 	/* ei->i_data[EXT4_IND_BLOCK] */
259 	if (i_data[0]) {
260 		retval = ext4_journal_ensure_credits(handle,
261 			EXT4_RESERVE_TRANS_BLOCKS,
262 			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
263 		if (retval < 0)
264 			return retval;
265 		ext4_free_blocks(handle, inode, NULL,
266 				le32_to_cpu(i_data[0]), 1,
267 				 EXT4_FREE_BLOCKS_METADATA |
268 				 EXT4_FREE_BLOCKS_FORGET);
269 	}
270 
271 	/* ei->i_data[EXT4_DIND_BLOCK] */
272 	if (i_data[1]) {
273 		retval = free_dind_blocks(handle, inode, i_data[1]);
274 		if (retval)
275 			return retval;
276 	}
277 
278 	/* ei->i_data[EXT4_TIND_BLOCK] */
279 	if (i_data[2]) {
280 		retval = free_tind_blocks(handle, inode, i_data[2]);
281 		if (retval)
282 			return retval;
283 	}
284 	return 0;
285 }
286 
ext4_ext_swap_inode_data(handle_t * handle,struct inode * inode,struct inode * tmp_inode)287 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
288 						struct inode *tmp_inode)
289 {
290 	int retval, retval2 = 0;
291 	__le32	i_data[3];
292 	struct ext4_inode_info *ei = EXT4_I(inode);
293 	struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
294 
295 	/*
296 	 * One credit accounted for writing the
297 	 * i_data field of the original inode
298 	 */
299 	retval = ext4_journal_ensure_credits(handle, 1, 0);
300 	if (retval < 0)
301 		goto err_out;
302 
303 	i_data[0] = ei->i_data[EXT4_IND_BLOCK];
304 	i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
305 	i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
306 
307 	down_write(&EXT4_I(inode)->i_data_sem);
308 	/*
309 	 * if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
310 	 * happened after we started the migrate. We need to
311 	 * fail the migrate
312 	 */
313 	if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
314 		retval = -EAGAIN;
315 		up_write(&EXT4_I(inode)->i_data_sem);
316 		goto err_out;
317 	} else
318 		ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
319 	/*
320 	 * We have the extent map build with the tmp inode.
321 	 * Now copy the i_data across
322 	 */
323 	ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
324 	memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
325 
326 	/*
327 	 * Update i_blocks with the new blocks that got
328 	 * allocated while adding extents for extent index
329 	 * blocks.
330 	 *
331 	 * While converting to extents we need not
332 	 * update the original inode i_blocks for extent blocks
333 	 * via quota APIs. The quota update happened via tmp_inode already.
334 	 */
335 	spin_lock(&inode->i_lock);
336 	inode->i_blocks += tmp_inode->i_blocks;
337 	spin_unlock(&inode->i_lock);
338 	up_write(&EXT4_I(inode)->i_data_sem);
339 
340 	/*
341 	 * We mark the inode dirty after, because we decrement the
342 	 * i_blocks when freeing the indirect meta-data blocks
343 	 */
344 	retval = free_ind_block(handle, inode, i_data);
345 	retval2 = ext4_mark_inode_dirty(handle, inode);
346 	if (unlikely(retval2 && !retval))
347 		retval = retval2;
348 
349 err_out:
350 	return retval;
351 }
352 
free_ext_idx(handle_t * handle,struct inode * inode,struct ext4_extent_idx * ix)353 static int free_ext_idx(handle_t *handle, struct inode *inode,
354 					struct ext4_extent_idx *ix)
355 {
356 	int i, retval = 0;
357 	ext4_fsblk_t block;
358 	struct buffer_head *bh;
359 	struct ext4_extent_header *eh;
360 
361 	block = ext4_idx_pblock(ix);
362 	bh = ext4_sb_bread(inode->i_sb, block, 0);
363 	if (IS_ERR(bh))
364 		return PTR_ERR(bh);
365 
366 	eh = (struct ext4_extent_header *)bh->b_data;
367 	if (eh->eh_depth != 0) {
368 		ix = EXT_FIRST_INDEX(eh);
369 		for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
370 			retval = free_ext_idx(handle, inode, ix);
371 			if (retval) {
372 				put_bh(bh);
373 				return retval;
374 			}
375 		}
376 	}
377 	put_bh(bh);
378 	retval = ext4_journal_ensure_credits(handle, EXT4_RESERVE_TRANS_BLOCKS,
379 			ext4_free_metadata_revoke_credits(inode->i_sb, 1));
380 	if (retval < 0)
381 		return retval;
382 	ext4_free_blocks(handle, inode, NULL, block, 1,
383 			 EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
384 	return 0;
385 }
386 
387 /*
388  * Free the extent meta data blocks only
389  */
free_ext_block(handle_t * handle,struct inode * inode)390 static int free_ext_block(handle_t *handle, struct inode *inode)
391 {
392 	int i, retval = 0;
393 	struct ext4_inode_info *ei = EXT4_I(inode);
394 	struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
395 	struct ext4_extent_idx *ix;
396 	if (eh->eh_depth == 0)
397 		/*
398 		 * No extra blocks allocated for extent meta data
399 		 */
400 		return 0;
401 	ix = EXT_FIRST_INDEX(eh);
402 	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
403 		retval = free_ext_idx(handle, inode, ix);
404 		if (retval)
405 			return retval;
406 	}
407 	return retval;
408 }
409 
ext4_ext_migrate(struct inode * inode)410 int ext4_ext_migrate(struct inode *inode)
411 {
412 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
413 	handle_t *handle;
414 	int retval = 0, i;
415 	__le32 *i_data;
416 	struct ext4_inode_info *ei;
417 	struct inode *tmp_inode = NULL;
418 	struct migrate_struct lb;
419 	unsigned long max_entries;
420 	__u32 goal, tmp_csum_seed;
421 	uid_t owner[2];
422 
423 	/*
424 	 * If the filesystem does not support extents, or the inode
425 	 * already is extent-based, error out.
426 	 */
427 	if (!ext4_has_feature_extents(inode->i_sb) ||
428 	    (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
429 		return -EINVAL;
430 
431 	if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
432 		/*
433 		 * don't migrate fast symlink
434 		 */
435 		return retval;
436 
437 	percpu_down_write(&sbi->s_writepages_rwsem);
438 
439 	/*
440 	 * Worst case we can touch the allocation bitmaps and a block
441 	 * group descriptor block.  We do need to worry about
442 	 * credits for modifying the quota inode.
443 	 */
444 	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE,
445 		3 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
446 
447 	if (IS_ERR(handle)) {
448 		retval = PTR_ERR(handle);
449 		goto out_unlock;
450 	}
451 	goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
452 		EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
453 	owner[0] = i_uid_read(inode);
454 	owner[1] = i_gid_read(inode);
455 	tmp_inode = ext4_new_inode(handle, d_inode(inode->i_sb->s_root),
456 				   S_IFREG, NULL, goal, owner, 0);
457 	if (IS_ERR(tmp_inode)) {
458 		retval = PTR_ERR(tmp_inode);
459 		ext4_journal_stop(handle);
460 		goto out_unlock;
461 	}
462 	/*
463 	 * Use the correct seed for checksum (i.e. the seed from 'inode').  This
464 	 * is so that the metadata blocks will have the correct checksum after
465 	 * the migration.
466 	 */
467 	ei = EXT4_I(inode);
468 	tmp_csum_seed = EXT4_I(tmp_inode)->i_csum_seed;
469 	EXT4_I(tmp_inode)->i_csum_seed = ei->i_csum_seed;
470 	i_size_write(tmp_inode, i_size_read(inode));
471 	/*
472 	 * Set the i_nlink to zero so it will be deleted later
473 	 * when we drop inode reference.
474 	 */
475 	clear_nlink(tmp_inode);
476 
477 	ext4_ext_tree_init(handle, tmp_inode);
478 	ext4_journal_stop(handle);
479 
480 	/*
481 	 * start with one credit accounted for
482 	 * superblock modification.
483 	 *
484 	 * For the tmp_inode we already have committed the
485 	 * transaction that created the inode. Later as and
486 	 * when we add extents we extent the journal
487 	 */
488 	/*
489 	 * Even though we take i_rwsem we can still cause block
490 	 * allocation via mmap write to holes. If we have allocated
491 	 * new blocks we fail migrate.  New block allocation will
492 	 * clear EXT4_STATE_EXT_MIGRATE flag.  The flag is updated
493 	 * with i_data_sem held to prevent racing with block
494 	 * allocation.
495 	 */
496 	down_read(&EXT4_I(inode)->i_data_sem);
497 	ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
498 	up_read((&EXT4_I(inode)->i_data_sem));
499 
500 	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
501 	if (IS_ERR(handle)) {
502 		retval = PTR_ERR(handle);
503 		goto out_tmp_inode;
504 	}
505 
506 	i_data = ei->i_data;
507 	memset(&lb, 0, sizeof(lb));
508 
509 	/* 32 bit block address 4 bytes */
510 	max_entries = inode->i_sb->s_blocksize >> 2;
511 	for (i = 0; i < EXT4_NDIR_BLOCKS; i++) {
512 		if (i_data[i]) {
513 			retval = update_extent_range(handle, tmp_inode,
514 						le32_to_cpu(i_data[i]), &lb);
515 			if (retval)
516 				goto err_out;
517 		} else
518 			lb.curr_block++;
519 	}
520 	if (i_data[EXT4_IND_BLOCK]) {
521 		retval = update_ind_extent_range(handle, tmp_inode,
522 				le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
523 		if (retval)
524 			goto err_out;
525 	} else
526 		lb.curr_block += max_entries;
527 	if (i_data[EXT4_DIND_BLOCK]) {
528 		retval = update_dind_extent_range(handle, tmp_inode,
529 				le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
530 		if (retval)
531 			goto err_out;
532 	} else
533 		lb.curr_block += max_entries * max_entries;
534 	if (i_data[EXT4_TIND_BLOCK]) {
535 		retval = update_tind_extent_range(handle, tmp_inode,
536 				le32_to_cpu(i_data[EXT4_TIND_BLOCK]), &lb);
537 		if (retval)
538 			goto err_out;
539 	}
540 	/*
541 	 * Build the last extent
542 	 */
543 	retval = finish_range(handle, tmp_inode, &lb);
544 err_out:
545 	if (retval)
546 		/*
547 		 * Failure case delete the extent information with the
548 		 * tmp_inode
549 		 */
550 		free_ext_block(handle, tmp_inode);
551 	else {
552 		retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
553 		if (retval)
554 			/*
555 			 * if we fail to swap inode data free the extent
556 			 * details of the tmp inode
557 			 */
558 			free_ext_block(handle, tmp_inode);
559 	}
560 
561 	/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
562 	retval = ext4_journal_ensure_credits(handle, 1, 0);
563 	if (retval < 0)
564 		goto out_stop;
565 	/*
566 	 * Mark the tmp_inode as of size zero
567 	 */
568 	i_size_write(tmp_inode, 0);
569 
570 	/*
571 	 * set the  i_blocks count to zero
572 	 * so that the ext4_evict_inode() does the
573 	 * right job
574 	 *
575 	 * We don't need to take the i_lock because
576 	 * the inode is not visible to user space.
577 	 */
578 	tmp_inode->i_blocks = 0;
579 	EXT4_I(tmp_inode)->i_csum_seed = tmp_csum_seed;
580 
581 	/* Reset the extent details */
582 	ext4_ext_tree_init(handle, tmp_inode);
583 out_stop:
584 	ext4_journal_stop(handle);
585 out_tmp_inode:
586 	unlock_new_inode(tmp_inode);
587 	iput(tmp_inode);
588 out_unlock:
589 	percpu_up_write(&sbi->s_writepages_rwsem);
590 	return retval;
591 }
592 
593 /*
594  * Migrate a simple extent-based inode to use the i_blocks[] array
595  */
ext4_ind_migrate(struct inode * inode)596 int ext4_ind_migrate(struct inode *inode)
597 {
598 	struct ext4_extent_header	*eh;
599 	struct ext4_sb_info		*sbi = EXT4_SB(inode->i_sb);
600 	struct ext4_super_block		*es = sbi->s_es;
601 	struct ext4_inode_info		*ei = EXT4_I(inode);
602 	struct ext4_extent		*ex;
603 	unsigned int			i, len;
604 	ext4_lblk_t			start, end;
605 	ext4_fsblk_t			blk;
606 	handle_t			*handle;
607 	int				ret, ret2 = 0;
608 
609 	if (!ext4_has_feature_extents(inode->i_sb) ||
610 	    (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
611 		return -EINVAL;
612 
613 	if (ext4_has_feature_bigalloc(inode->i_sb))
614 		return -EOPNOTSUPP;
615 
616 	/*
617 	 * In order to get correct extent info, force all delayed allocation
618 	 * blocks to be allocated, otherwise delayed allocation blocks may not
619 	 * be reflected and bypass the checks on extent header.
620 	 */
621 	if (test_opt(inode->i_sb, DELALLOC))
622 		ext4_alloc_da_blocks(inode);
623 
624 	percpu_down_write(&sbi->s_writepages_rwsem);
625 
626 	handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
627 	if (IS_ERR(handle)) {
628 		ret = PTR_ERR(handle);
629 		goto out_unlock;
630 	}
631 
632 	down_write(&EXT4_I(inode)->i_data_sem);
633 	ret = ext4_ext_check_inode(inode);
634 	if (ret)
635 		goto errout;
636 
637 	eh = ext_inode_hdr(inode);
638 	ex  = EXT_FIRST_EXTENT(eh);
639 	if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||
640 	    eh->eh_depth != 0 || le16_to_cpu(eh->eh_entries) > 1) {
641 		ret = -EOPNOTSUPP;
642 		goto errout;
643 	}
644 	if (eh->eh_entries == 0)
645 		blk = len = start = end = 0;
646 	else {
647 		len = le16_to_cpu(ex->ee_len);
648 		blk = ext4_ext_pblock(ex);
649 		start = le32_to_cpu(ex->ee_block);
650 		end = start + len - 1;
651 		if (end >= EXT4_NDIR_BLOCKS) {
652 			ret = -EOPNOTSUPP;
653 			goto errout;
654 		}
655 	}
656 
657 	ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
658 	memset(ei->i_data, 0, sizeof(ei->i_data));
659 	for (i = start; i <= end; i++)
660 		ei->i_data[i] = cpu_to_le32(blk++);
661 	ret2 = ext4_mark_inode_dirty(handle, inode);
662 	if (unlikely(ret2 && !ret))
663 		ret = ret2;
664 errout:
665 	ext4_journal_stop(handle);
666 	up_write(&EXT4_I(inode)->i_data_sem);
667 out_unlock:
668 	percpu_up_write(&sbi->s_writepages_rwsem);
669 	return ret;
670 }
671