Merge tag 'pm-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
[linux-block.git] / fs / ext4 / move_extent.c
... / ...
CommitLineData
1// SPDX-License-Identifier: LGPL-2.1
2/*
3 * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
4 * Written by Takashi Sato <t-sato@yk.jp.nec.com>
5 * Akira Fujita <a-fujita@rs.jp.nec.com>
6 */
7
8#include <linux/fs.h>
9#include <linux/quotaops.h>
10#include <linux/slab.h>
11#include <linux/sched/mm.h>
12#include "ext4_jbd2.h"
13#include "ext4.h"
14#include "ext4_extents.h"
15
16/**
17 * get_ext_path() - Find an extent path for designated logical block number.
18 * @inode: inode to be searched
19 * @lblock: logical block number to find an extent path
20 * @path: pointer to an extent path
21 *
22 * ext4_find_extent wrapper. Return an extent path pointer on success,
23 * or an error pointer on failure.
24 */
25static inline struct ext4_ext_path *
26get_ext_path(struct inode *inode, ext4_lblk_t lblock,
27 struct ext4_ext_path *path)
28{
29 path = ext4_find_extent(inode, lblock, path, EXT4_EX_NOCACHE);
30 if (IS_ERR(path))
31 return path;
32 if (path[ext_depth(inode)].p_ext == NULL) {
33 ext4_free_ext_path(path);
34 return ERR_PTR(-ENODATA);
35 }
36 return path;
37}
38
39/**
40 * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem
41 * @first: inode to be locked
42 * @second: inode to be locked
43 *
44 * Acquire write lock of i_data_sem of the two inodes
45 */
46void
47ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
48{
49 if (first < second) {
50 down_write(&EXT4_I(first)->i_data_sem);
51 down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER);
52 } else {
53 down_write(&EXT4_I(second)->i_data_sem);
54 down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER);
55
56 }
57}
58
59/**
60 * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
61 *
62 * @orig_inode: original inode structure to be released its lock first
63 * @donor_inode: donor inode structure to be released its lock second
64 * Release write lock of i_data_sem of two inodes (orig and donor).
65 */
66void
67ext4_double_up_write_data_sem(struct inode *orig_inode,
68 struct inode *donor_inode)
69{
70 up_write(&EXT4_I(orig_inode)->i_data_sem);
71 up_write(&EXT4_I(donor_inode)->i_data_sem);
72}
73
74/**
75 * mext_check_coverage - Check that all extents in range has the same type
76 *
77 * @inode: inode in question
78 * @from: block offset of inode
79 * @count: block count to be checked
80 * @unwritten: extents expected to be unwritten
81 * @err: pointer to save error value
82 *
83 * Return 1 if all extents in range has expected type, and zero otherwise.
84 */
85static int
86mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
87 int unwritten, int *err)
88{
89 struct ext4_ext_path *path = NULL;
90 struct ext4_extent *ext;
91 int ret = 0;
92 ext4_lblk_t last = from + count;
93 while (from < last) {
94 path = get_ext_path(inode, from, path);
95 if (IS_ERR(path)) {
96 *err = PTR_ERR(path);
97 return ret;
98 }
99 ext = path[ext_depth(inode)].p_ext;
100 if (unwritten != ext4_ext_is_unwritten(ext))
101 goto out;
102 from += ext4_ext_get_actual_len(ext);
103 }
104 ret = 1;
105out:
106 ext4_free_ext_path(path);
107 return ret;
108}
109
110/**
111 * mext_folio_double_lock - Grab and lock folio on both @inode1 and @inode2
112 *
113 * @inode1: the inode structure
114 * @inode2: the inode structure
115 * @index1: folio index
116 * @index2: folio index
117 * @folio: result folio vector
118 *
119 * Grab two locked folio for inode's by inode order
120 */
121static int
122mext_folio_double_lock(struct inode *inode1, struct inode *inode2,
123 pgoff_t index1, pgoff_t index2, struct folio *folio[2])
124{
125 struct address_space *mapping[2];
126 unsigned int flags;
127
128 BUG_ON(!inode1 || !inode2);
129 if (inode1 < inode2) {
130 mapping[0] = inode1->i_mapping;
131 mapping[1] = inode2->i_mapping;
132 } else {
133 swap(index1, index2);
134 mapping[0] = inode2->i_mapping;
135 mapping[1] = inode1->i_mapping;
136 }
137
138 flags = memalloc_nofs_save();
139 folio[0] = __filemap_get_folio(mapping[0], index1, FGP_WRITEBEGIN,
140 mapping_gfp_mask(mapping[0]));
141 if (IS_ERR(folio[0])) {
142 memalloc_nofs_restore(flags);
143 return PTR_ERR(folio[0]);
144 }
145
146 folio[1] = __filemap_get_folio(mapping[1], index2, FGP_WRITEBEGIN,
147 mapping_gfp_mask(mapping[1]));
148 memalloc_nofs_restore(flags);
149 if (IS_ERR(folio[1])) {
150 folio_unlock(folio[0]);
151 folio_put(folio[0]);
152 return PTR_ERR(folio[1]);
153 }
154 /*
155 * __filemap_get_folio() may not wait on folio's writeback if
156 * BDI not demand that. But it is reasonable to be very conservative
157 * here and explicitly wait on folio's writeback
158 */
159 folio_wait_writeback(folio[0]);
160 folio_wait_writeback(folio[1]);
161 if (inode1 > inode2)
162 swap(folio[0], folio[1]);
163
164 return 0;
165}
166
167/* Force folio buffers uptodate w/o dropping folio's lock */
168static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to)
169{
170 struct inode *inode = folio->mapping->host;
171 sector_t block;
172 struct buffer_head *bh, *head;
173 unsigned int blocksize, block_start, block_end;
174 int nr = 0;
175 bool partial = false;
176
177 BUG_ON(!folio_test_locked(folio));
178 BUG_ON(folio_test_writeback(folio));
179
180 if (folio_test_uptodate(folio))
181 return 0;
182
183 blocksize = i_blocksize(inode);
184 head = folio_buffers(folio);
185 if (!head)
186 head = create_empty_buffers(folio, blocksize, 0);
187
188 block = folio_pos(folio) >> inode->i_blkbits;
189 block_end = 0;
190 bh = head;
191 do {
192 block_start = block_end;
193 block_end = block_start + blocksize;
194 if (block_end <= from || block_start >= to) {
195 if (!buffer_uptodate(bh))
196 partial = true;
197 continue;
198 }
199 if (buffer_uptodate(bh))
200 continue;
201 if (!buffer_mapped(bh)) {
202 int err = ext4_get_block(inode, block, bh, 0);
203 if (err)
204 return err;
205 if (!buffer_mapped(bh)) {
206 folio_zero_range(folio, block_start, blocksize);
207 set_buffer_uptodate(bh);
208 continue;
209 }
210 }
211 lock_buffer(bh);
212 if (buffer_uptodate(bh)) {
213 unlock_buffer(bh);
214 continue;
215 }
216 ext4_read_bh_nowait(bh, 0, NULL, false);
217 nr++;
218 } while (block++, (bh = bh->b_this_page) != head);
219
220 /* No io required */
221 if (!nr)
222 goto out;
223
224 bh = head;
225 do {
226 if (bh_offset(bh) + blocksize <= from)
227 continue;
228 if (bh_offset(bh) > to)
229 break;
230 wait_on_buffer(bh);
231 if (buffer_uptodate(bh))
232 continue;
233 return -EIO;
234 } while ((bh = bh->b_this_page) != head);
235out:
236 if (!partial)
237 folio_mark_uptodate(folio);
238 return 0;
239}
240
241/**
242 * move_extent_per_page - Move extent data per page
243 *
244 * @o_filp: file structure of original file
245 * @donor_inode: donor inode
246 * @orig_page_offset: page index on original file
247 * @donor_page_offset: page index on donor file
248 * @data_offset_in_page: block index where data swapping starts
249 * @block_len_in_page: the number of blocks to be swapped
250 * @unwritten: orig extent is unwritten or not
251 * @err: pointer to save return value
252 *
253 * Save the data in original inode blocks and replace original inode extents
254 * with donor inode extents by calling ext4_swap_extents().
255 * Finally, write out the saved data in new original inode blocks. Return
256 * replaced block count.
257 */
258static int
259move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
260 pgoff_t orig_page_offset, pgoff_t donor_page_offset,
261 int data_offset_in_page,
262 int block_len_in_page, int unwritten, int *err)
263{
264 struct inode *orig_inode = file_inode(o_filp);
265 struct folio *folio[2] = {NULL, NULL};
266 handle_t *handle;
267 ext4_lblk_t orig_blk_offset, donor_blk_offset;
268 unsigned long blocksize = orig_inode->i_sb->s_blocksize;
269 unsigned int tmp_data_size, data_size, replaced_size;
270 int i, err2, jblocks, retries = 0;
271 int replaced_count = 0;
272 int from;
273 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
274 struct super_block *sb = orig_inode->i_sb;
275 struct buffer_head *bh = NULL;
276
277 /*
278 * It needs twice the amount of ordinary journal buffers because
279 * inode and donor_inode may change each different metadata blocks.
280 */
281again:
282 *err = 0;
283 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
284 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks);
285 if (IS_ERR(handle)) {
286 *err = PTR_ERR(handle);
287 return 0;
288 }
289
290 orig_blk_offset = orig_page_offset * blocks_per_page +
291 data_offset_in_page;
292
293 donor_blk_offset = donor_page_offset * blocks_per_page +
294 data_offset_in_page;
295
296 /* Calculate data_size */
297 if ((orig_blk_offset + block_len_in_page - 1) ==
298 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
299 /* Replace the last block */
300 tmp_data_size = orig_inode->i_size & (blocksize - 1);
301 /*
302 * If data_size equal zero, it shows data_size is multiples of
303 * blocksize. So we set appropriate value.
304 */
305 if (tmp_data_size == 0)
306 tmp_data_size = blocksize;
307
308 data_size = tmp_data_size +
309 ((block_len_in_page - 1) << orig_inode->i_blkbits);
310 } else
311 data_size = block_len_in_page << orig_inode->i_blkbits;
312
313 replaced_size = data_size;
314
315 *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset,
316 donor_page_offset, folio);
317 if (unlikely(*err < 0))
318 goto stop_journal;
319 /*
320 * If orig extent was unwritten it can become initialized
321 * at any time after i_data_sem was dropped, in order to
322 * serialize with delalloc we have recheck extent while we
323 * hold page's lock, if it is still the case data copy is not
324 * necessary, just swap data blocks between orig and donor.
325 */
326 if (unwritten) {
327 ext4_double_down_write_data_sem(orig_inode, donor_inode);
328 /* If any of extents in range became initialized we have to
329 * fallback to data copying */
330 unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
331 block_len_in_page, 1, err);
332 if (*err)
333 goto drop_data_sem;
334
335 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset,
336 block_len_in_page, 1, err);
337 if (*err)
338 goto drop_data_sem;
339
340 if (!unwritten) {
341 ext4_double_up_write_data_sem(orig_inode, donor_inode);
342 goto data_copy;
343 }
344 if (!filemap_release_folio(folio[0], 0) ||
345 !filemap_release_folio(folio[1], 0)) {
346 *err = -EBUSY;
347 goto drop_data_sem;
348 }
349 replaced_count = ext4_swap_extents(handle, orig_inode,
350 donor_inode, orig_blk_offset,
351 donor_blk_offset,
352 block_len_in_page, 1, err);
353 drop_data_sem:
354 ext4_double_up_write_data_sem(orig_inode, donor_inode);
355 goto unlock_folios;
356 }
357data_copy:
358 from = offset_in_folio(folio[0],
359 orig_blk_offset << orig_inode->i_blkbits);
360 *err = mext_page_mkuptodate(folio[0], from, from + replaced_size);
361 if (*err)
362 goto unlock_folios;
363
364 /* At this point all buffers in range are uptodate, old mapping layout
365 * is no longer required, try to drop it now. */
366 if (!filemap_release_folio(folio[0], 0) ||
367 !filemap_release_folio(folio[1], 0)) {
368 *err = -EBUSY;
369 goto unlock_folios;
370 }
371 ext4_double_down_write_data_sem(orig_inode, donor_inode);
372 replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode,
373 orig_blk_offset, donor_blk_offset,
374 block_len_in_page, 1, err);
375 ext4_double_up_write_data_sem(orig_inode, donor_inode);
376 if (*err) {
377 if (replaced_count) {
378 block_len_in_page = replaced_count;
379 replaced_size =
380 block_len_in_page << orig_inode->i_blkbits;
381 } else
382 goto unlock_folios;
383 }
384 /* Perform all necessary steps similar write_begin()/write_end()
385 * but keeping in mind that i_size will not change */
386 bh = folio_buffers(folio[0]);
387 if (!bh)
388 bh = create_empty_buffers(folio[0],
389 1 << orig_inode->i_blkbits, 0);
390 for (i = 0; i < from >> orig_inode->i_blkbits; i++)
391 bh = bh->b_this_page;
392 for (i = 0; i < block_len_in_page; i++) {
393 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0);
394 if (*err < 0)
395 goto repair_branches;
396 bh = bh->b_this_page;
397 }
398
399 block_commit_write(folio[0], from, from + replaced_size);
400
401 /* Even in case of data=writeback it is reasonable to pin
402 * inode to transaction, to prevent unexpected data loss */
403 *err = ext4_jbd2_inode_add_write(handle, orig_inode,
404 (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size);
405
406unlock_folios:
407 folio_unlock(folio[0]);
408 folio_put(folio[0]);
409 folio_unlock(folio[1]);
410 folio_put(folio[1]);
411stop_journal:
412 ext4_journal_stop(handle);
413 if (*err == -ENOSPC &&
414 ext4_should_retry_alloc(sb, &retries))
415 goto again;
416 /* Buffer was busy because probably is pinned to journal transaction,
417 * force transaction commit may help to free it. */
418 if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal &&
419 jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal))
420 goto again;
421 return replaced_count;
422
423repair_branches:
424 /*
425 * This should never ever happen!
426 * Extents are swapped already, but we are not able to copy data.
427 * Try to swap extents to it's original places
428 */
429 ext4_double_down_write_data_sem(orig_inode, donor_inode);
430 replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode,
431 orig_blk_offset, donor_blk_offset,
432 block_len_in_page, 0, &err2);
433 ext4_double_up_write_data_sem(orig_inode, donor_inode);
434 if (replaced_count != block_len_in_page) {
435 ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset),
436 EIO, "Unable to copy data block,"
437 " data will be lost.");
438 *err = -EIO;
439 }
440 replaced_count = 0;
441 goto unlock_folios;
442}
443
444/**
445 * mext_check_arguments - Check whether move extent can be done
446 *
447 * @orig_inode: original inode
448 * @donor_inode: donor inode
449 * @orig_start: logical start offset in block for orig
450 * @donor_start: logical start offset in block for donor
451 * @len: the number of blocks to be moved
452 *
453 * Check the arguments of ext4_move_extents() whether the files can be
454 * exchanged with each other.
455 * Return 0 on success, or a negative error value on failure.
456 */
457static int
458mext_check_arguments(struct inode *orig_inode,
459 struct inode *donor_inode, __u64 orig_start,
460 __u64 donor_start, __u64 *len)
461{
462 __u64 orig_eof, donor_eof;
463 unsigned int blkbits = orig_inode->i_blkbits;
464 unsigned int blocksize = 1 << blkbits;
465
466 orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits;
467 donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits;
468
469
470 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
471 ext4_debug("ext4 move extent: suid or sgid is set"
472 " to donor file [ino:orig %lu, donor %lu]\n",
473 orig_inode->i_ino, donor_inode->i_ino);
474 return -EINVAL;
475 }
476
477 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
478 return -EPERM;
479
480 /* Ext4 move extent does not support swap files */
481 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
482 ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n",
483 orig_inode->i_ino, donor_inode->i_ino);
484 return -ETXTBSY;
485 }
486
487 if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) {
488 ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n",
489 orig_inode->i_ino, donor_inode->i_ino);
490 return -EOPNOTSUPP;
491 }
492
493 /* Ext4 move extent supports only extent based file */
494 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
495 ext4_debug("ext4 move extent: orig file is not extents "
496 "based file [ino:orig %lu]\n", orig_inode->i_ino);
497 return -EOPNOTSUPP;
498 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
499 ext4_debug("ext4 move extent: donor file is not extents "
500 "based file [ino:donor %lu]\n", donor_inode->i_ino);
501 return -EOPNOTSUPP;
502 }
503
504 if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
505 ext4_debug("ext4 move extent: File size is 0 byte\n");
506 return -EINVAL;
507 }
508
509 /* Start offset should be same */
510 if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) !=
511 (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) {
512 ext4_debug("ext4 move extent: orig and donor's start "
513 "offsets are not aligned [ino:orig %lu, donor %lu]\n",
514 orig_inode->i_ino, donor_inode->i_ino);
515 return -EINVAL;
516 }
517
518 if ((orig_start >= EXT_MAX_BLOCKS) ||
519 (donor_start >= EXT_MAX_BLOCKS) ||
520 (*len > EXT_MAX_BLOCKS) ||
521 (donor_start + *len >= EXT_MAX_BLOCKS) ||
522 (orig_start + *len >= EXT_MAX_BLOCKS)) {
523 ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
524 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
525 orig_inode->i_ino, donor_inode->i_ino);
526 return -EINVAL;
527 }
528 if (orig_eof <= orig_start)
529 *len = 0;
530 else if (orig_eof < orig_start + *len - 1)
531 *len = orig_eof - orig_start;
532 if (donor_eof <= donor_start)
533 *len = 0;
534 else if (donor_eof < donor_start + *len - 1)
535 *len = donor_eof - donor_start;
536 if (!*len) {
537 ext4_debug("ext4 move extent: len should not be 0 "
538 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
539 donor_inode->i_ino);
540 return -EINVAL;
541 }
542
543 return 0;
544}
545
546/**
547 * ext4_move_extents - Exchange the specified range of a file
548 *
549 * @o_filp: file structure of the original file
550 * @d_filp: file structure of the donor file
551 * @orig_blk: start offset in block for orig
552 * @donor_blk: start offset in block for donor
553 * @len: the number of blocks to be moved
554 * @moved_len: moved block length
555 *
556 * This function returns 0 and moved block length is set in moved_len
557 * if succeed, otherwise returns error value.
558 *
559 */
560int
561ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
562 __u64 donor_blk, __u64 len, __u64 *moved_len)
563{
564 struct inode *orig_inode = file_inode(o_filp);
565 struct inode *donor_inode = file_inode(d_filp);
566 struct ext4_ext_path *path = NULL;
567 int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
568 ext4_lblk_t o_end, o_start = orig_blk;
569 ext4_lblk_t d_start = donor_blk;
570 int ret;
571
572 if (orig_inode->i_sb != donor_inode->i_sb) {
573 ext4_debug("ext4 move extent: The argument files "
574 "should be in same FS [ino:orig %lu, donor %lu]\n",
575 orig_inode->i_ino, donor_inode->i_ino);
576 return -EINVAL;
577 }
578
579 /* orig and donor should be different inodes */
580 if (orig_inode == donor_inode) {
581 ext4_debug("ext4 move extent: The argument files should not "
582 "be same inode [ino:orig %lu, donor %lu]\n",
583 orig_inode->i_ino, donor_inode->i_ino);
584 return -EINVAL;
585 }
586
587 /* Regular file check */
588 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
589 ext4_debug("ext4 move extent: The argument files should be "
590 "regular file [ino:orig %lu, donor %lu]\n",
591 orig_inode->i_ino, donor_inode->i_ino);
592 return -EINVAL;
593 }
594
595 /* TODO: it's not obvious how to swap blocks for inodes with full
596 journaling enabled */
597 if (ext4_should_journal_data(orig_inode) ||
598 ext4_should_journal_data(donor_inode)) {
599 ext4_msg(orig_inode->i_sb, KERN_ERR,
600 "Online defrag not supported with data journaling");
601 return -EOPNOTSUPP;
602 }
603
604 if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) {
605 ext4_msg(orig_inode->i_sb, KERN_ERR,
606 "Online defrag not supported for encrypted files");
607 return -EOPNOTSUPP;
608 }
609
610 /* Protect orig and donor inodes against a truncate */
611 lock_two_nondirectories(orig_inode, donor_inode);
612
613 /* Wait for all existing dio workers */
614 inode_dio_wait(orig_inode);
615 inode_dio_wait(donor_inode);
616
617 /* Protect extent tree against block allocations via delalloc */
618 ext4_double_down_write_data_sem(orig_inode, donor_inode);
619 /* Check the filesystem environment whether move_extent can be done */
620 ret = mext_check_arguments(orig_inode, donor_inode, orig_blk,
621 donor_blk, &len);
622 if (ret)
623 goto out;
624 o_end = o_start + len;
625
626 *moved_len = 0;
627 while (o_start < o_end) {
628 struct ext4_extent *ex;
629 ext4_lblk_t cur_blk, next_blk;
630 pgoff_t orig_page_index, donor_page_index;
631 int offset_in_page;
632 int unwritten, cur_len;
633
634 path = get_ext_path(orig_inode, o_start, path);
635 if (IS_ERR(path)) {
636 ret = PTR_ERR(path);
637 goto out;
638 }
639 ex = path[path->p_depth].p_ext;
640 cur_blk = le32_to_cpu(ex->ee_block);
641 cur_len = ext4_ext_get_actual_len(ex);
642 /* Check hole before the start pos */
643 if (cur_blk + cur_len - 1 < o_start) {
644 next_blk = ext4_ext_next_allocated_block(path);
645 if (next_blk == EXT_MAX_BLOCKS) {
646 ret = -ENODATA;
647 goto out;
648 }
649 d_start += next_blk - o_start;
650 o_start = next_blk;
651 continue;
652 /* Check hole after the start pos */
653 } else if (cur_blk > o_start) {
654 /* Skip hole */
655 d_start += cur_blk - o_start;
656 o_start = cur_blk;
657 /* Extent inside requested range ?*/
658 if (cur_blk >= o_end)
659 goto out;
660 } else { /* in_range(o_start, o_blk, o_len) */
661 cur_len += cur_blk - o_start;
662 }
663 unwritten = ext4_ext_is_unwritten(ex);
664 if (o_end - o_start < cur_len)
665 cur_len = o_end - o_start;
666
667 orig_page_index = o_start >> (PAGE_SHIFT -
668 orig_inode->i_blkbits);
669 donor_page_index = d_start >> (PAGE_SHIFT -
670 donor_inode->i_blkbits);
671 offset_in_page = o_start % blocks_per_page;
672 if (cur_len > blocks_per_page - offset_in_page)
673 cur_len = blocks_per_page - offset_in_page;
674 /*
675 * Up semaphore to avoid following problems:
676 * a. transaction deadlock among ext4_journal_start,
677 * ->write_begin via pagefault, and jbd2_journal_commit
678 * b. racing with ->read_folio, ->write_begin, and
679 * ext4_get_block in move_extent_per_page
680 */
681 ext4_double_up_write_data_sem(orig_inode, donor_inode);
682 /* Swap original branches with new branches */
683 *moved_len += move_extent_per_page(o_filp, donor_inode,
684 orig_page_index, donor_page_index,
685 offset_in_page, cur_len,
686 unwritten, &ret);
687 ext4_double_down_write_data_sem(orig_inode, donor_inode);
688 if (ret < 0)
689 break;
690 o_start += cur_len;
691 d_start += cur_len;
692 }
693
694out:
695 if (*moved_len) {
696 ext4_discard_preallocations(orig_inode);
697 ext4_discard_preallocations(donor_inode);
698 }
699
700 ext4_free_ext_path(path);
701 ext4_double_up_write_data_sem(orig_inode, donor_inode);
702 unlock_two_nondirectories(orig_inode, donor_inode);
703
704 return ret;
705}