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Merge branch 'parisc-3.16-5' of git://git.kernel.org/pub/scm/linux/kernel/git/deller...
[deliverable/linux.git] / fs / ext4 / move_extent.c
1 /*
2 * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
3 * Written by Takashi Sato <t-sato@yk.jp.nec.com>
4 * Akira Fujita <a-fujita@rs.jp.nec.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of version 2.1 of the GNU Lesser General Public License
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16 #include <linux/fs.h>
17 #include <linux/quotaops.h>
18 #include <linux/slab.h>
19 #include "ext4_jbd2.h"
20 #include "ext4.h"
21 #include "ext4_extents.h"
22
23 /**
24 * get_ext_path - Find an extent path for designated logical block number.
25 *
26 * @inode: an inode which is searched
27 * @lblock: logical block number to find an extent path
28 * @path: pointer to an extent path pointer (for output)
29 *
30 * ext4_ext_find_extent wrapper. Return 0 on success, or a negative error value
31 * on failure.
32 */
33 static inline int
34 get_ext_path(struct inode *inode, ext4_lblk_t lblock,
35 struct ext4_ext_path **orig_path)
36 {
37 int ret = 0;
38 struct ext4_ext_path *path;
39
40 path = ext4_ext_find_extent(inode, lblock, *orig_path, EXT4_EX_NOCACHE);
41 if (IS_ERR(path))
42 ret = PTR_ERR(path);
43 else if (path[ext_depth(inode)].p_ext == NULL)
44 ret = -ENODATA;
45 else
46 *orig_path = path;
47
48 return ret;
49 }
50
51 /**
52 * copy_extent_status - Copy the extent's initialization status
53 *
54 * @src: an extent for getting initialize status
55 * @dest: an extent to be set the status
56 */
57 static void
58 copy_extent_status(struct ext4_extent *src, struct ext4_extent *dest)
59 {
60 if (ext4_ext_is_unwritten(src))
61 ext4_ext_mark_unwritten(dest);
62 else
63 dest->ee_len = cpu_to_le16(ext4_ext_get_actual_len(dest));
64 }
65
66 /**
67 * mext_next_extent - Search for the next extent and set it to "extent"
68 *
69 * @inode: inode which is searched
70 * @path: this will obtain data for the next extent
71 * @extent: pointer to the next extent we have just gotten
72 *
73 * Search the next extent in the array of ext4_ext_path structure (@path)
74 * and set it to ext4_extent structure (@extent). In addition, the member of
75 * @path (->p_ext) also points the next extent. Return 0 on success, 1 if
76 * ext4_ext_path structure refers to the last extent, or a negative error
77 * value on failure.
78 */
79 int
80 mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
81 struct ext4_extent **extent)
82 {
83 struct ext4_extent_header *eh;
84 int ppos, leaf_ppos = path->p_depth;
85
86 ppos = leaf_ppos;
87 if (EXT_LAST_EXTENT(path[ppos].p_hdr) > path[ppos].p_ext) {
88 /* leaf block */
89 *extent = ++path[ppos].p_ext;
90 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
91 return 0;
92 }
93
94 while (--ppos >= 0) {
95 if (EXT_LAST_INDEX(path[ppos].p_hdr) >
96 path[ppos].p_idx) {
97 int cur_ppos = ppos;
98
99 /* index block */
100 path[ppos].p_idx++;
101 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
102 if (path[ppos+1].p_bh)
103 brelse(path[ppos+1].p_bh);
104 path[ppos+1].p_bh =
105 sb_bread(inode->i_sb, path[ppos].p_block);
106 if (!path[ppos+1].p_bh)
107 return -EIO;
108 path[ppos+1].p_hdr =
109 ext_block_hdr(path[ppos+1].p_bh);
110
111 /* Halfway index block */
112 while (++cur_ppos < leaf_ppos) {
113 path[cur_ppos].p_idx =
114 EXT_FIRST_INDEX(path[cur_ppos].p_hdr);
115 path[cur_ppos].p_block =
116 ext4_idx_pblock(path[cur_ppos].p_idx);
117 if (path[cur_ppos+1].p_bh)
118 brelse(path[cur_ppos+1].p_bh);
119 path[cur_ppos+1].p_bh = sb_bread(inode->i_sb,
120 path[cur_ppos].p_block);
121 if (!path[cur_ppos+1].p_bh)
122 return -EIO;
123 path[cur_ppos+1].p_hdr =
124 ext_block_hdr(path[cur_ppos+1].p_bh);
125 }
126
127 path[leaf_ppos].p_ext = *extent = NULL;
128
129 eh = path[leaf_ppos].p_hdr;
130 if (le16_to_cpu(eh->eh_entries) == 0)
131 /* empty leaf is found */
132 return -ENODATA;
133
134 /* leaf block */
135 path[leaf_ppos].p_ext = *extent =
136 EXT_FIRST_EXTENT(path[leaf_ppos].p_hdr);
137 path[leaf_ppos].p_block =
138 ext4_ext_pblock(path[leaf_ppos].p_ext);
139 return 0;
140 }
141 }
142 /* We found the last extent */
143 return 1;
144 }
145
146 /**
147 * ext4_double_down_write_data_sem - Acquire two inodes' write lock
148 * of i_data_sem
149 *
150 * Acquire write lock of i_data_sem of the two inodes
151 */
152 void
153 ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
154 {
155 if (first < second) {
156 down_write(&EXT4_I(first)->i_data_sem);
157 down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING);
158 } else {
159 down_write(&EXT4_I(second)->i_data_sem);
160 down_write_nested(&EXT4_I(first)->i_data_sem, SINGLE_DEPTH_NESTING);
161
162 }
163 }
164
165 /**
166 * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
167 *
168 * @orig_inode: original inode structure to be released its lock first
169 * @donor_inode: donor inode structure to be released its lock second
170 * Release write lock of i_data_sem of two inodes (orig and donor).
171 */
172 void
173 ext4_double_up_write_data_sem(struct inode *orig_inode,
174 struct inode *donor_inode)
175 {
176 up_write(&EXT4_I(orig_inode)->i_data_sem);
177 up_write(&EXT4_I(donor_inode)->i_data_sem);
178 }
179
180 /**
181 * mext_insert_across_blocks - Insert extents across leaf block
182 *
183 * @handle: journal handle
184 * @orig_inode: original inode
185 * @o_start: first original extent to be changed
186 * @o_end: last original extent to be changed
187 * @start_ext: first new extent to be inserted
188 * @new_ext: middle of new extent to be inserted
189 * @end_ext: last new extent to be inserted
190 *
191 * Allocate a new leaf block and insert extents into it. Return 0 on success,
192 * or a negative error value on failure.
193 */
194 static int
195 mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
196 struct ext4_extent *o_start, struct ext4_extent *o_end,
197 struct ext4_extent *start_ext, struct ext4_extent *new_ext,
198 struct ext4_extent *end_ext)
199 {
200 struct ext4_ext_path *orig_path = NULL;
201 ext4_lblk_t eblock = 0;
202 int new_flag = 0;
203 int end_flag = 0;
204 int err = 0;
205
206 if (start_ext->ee_len && new_ext->ee_len && end_ext->ee_len) {
207 if (o_start == o_end) {
208
209 /* start_ext new_ext end_ext
210 * donor |---------|-----------|--------|
211 * orig |------------------------------|
212 */
213 end_flag = 1;
214 } else {
215
216 /* start_ext new_ext end_ext
217 * donor |---------|----------|---------|
218 * orig |---------------|--------------|
219 */
220 o_end->ee_block = end_ext->ee_block;
221 o_end->ee_len = end_ext->ee_len;
222 ext4_ext_store_pblock(o_end, ext4_ext_pblock(end_ext));
223 }
224
225 o_start->ee_len = start_ext->ee_len;
226 eblock = le32_to_cpu(start_ext->ee_block);
227 new_flag = 1;
228
229 } else if (start_ext->ee_len && new_ext->ee_len &&
230 !end_ext->ee_len && o_start == o_end) {
231
232 /* start_ext new_ext
233 * donor |--------------|---------------|
234 * orig |------------------------------|
235 */
236 o_start->ee_len = start_ext->ee_len;
237 eblock = le32_to_cpu(start_ext->ee_block);
238 new_flag = 1;
239
240 } else if (!start_ext->ee_len && new_ext->ee_len &&
241 end_ext->ee_len && o_start == o_end) {
242
243 /* new_ext end_ext
244 * donor |--------------|---------------|
245 * orig |------------------------------|
246 */
247 o_end->ee_block = end_ext->ee_block;
248 o_end->ee_len = end_ext->ee_len;
249 ext4_ext_store_pblock(o_end, ext4_ext_pblock(end_ext));
250
251 /*
252 * Set 0 to the extent block if new_ext was
253 * the first block.
254 */
255 if (new_ext->ee_block)
256 eblock = le32_to_cpu(new_ext->ee_block);
257
258 new_flag = 1;
259 } else {
260 ext4_debug("ext4 move extent: Unexpected insert case\n");
261 return -EIO;
262 }
263
264 if (new_flag) {
265 err = get_ext_path(orig_inode, eblock, &orig_path);
266 if (err)
267 goto out;
268
269 if (ext4_ext_insert_extent(handle, orig_inode,
270 orig_path, new_ext, 0))
271 goto out;
272 }
273
274 if (end_flag) {
275 err = get_ext_path(orig_inode,
276 le32_to_cpu(end_ext->ee_block) - 1, &orig_path);
277 if (err)
278 goto out;
279
280 if (ext4_ext_insert_extent(handle, orig_inode,
281 orig_path, end_ext, 0))
282 goto out;
283 }
284 out:
285 if (orig_path) {
286 ext4_ext_drop_refs(orig_path);
287 kfree(orig_path);
288 }
289
290 return err;
291
292 }
293
294 /**
295 * mext_insert_inside_block - Insert new extent to the extent block
296 *
297 * @o_start: first original extent to be moved
298 * @o_end: last original extent to be moved
299 * @start_ext: first new extent to be inserted
300 * @new_ext: middle of new extent to be inserted
301 * @end_ext: last new extent to be inserted
302 * @eh: extent header of target leaf block
303 * @range_to_move: used to decide how to insert extent
304 *
305 * Insert extents into the leaf block. The extent (@o_start) is overwritten
306 * by inserted extents.
307 */
308 static void
309 mext_insert_inside_block(struct ext4_extent *o_start,
310 struct ext4_extent *o_end,
311 struct ext4_extent *start_ext,
312 struct ext4_extent *new_ext,
313 struct ext4_extent *end_ext,
314 struct ext4_extent_header *eh,
315 int range_to_move)
316 {
317 int i = 0;
318 unsigned long len;
319
320 /* Move the existing extents */
321 if (range_to_move && o_end < EXT_LAST_EXTENT(eh)) {
322 len = (unsigned long)(EXT_LAST_EXTENT(eh) + 1) -
323 (unsigned long)(o_end + 1);
324 memmove(o_end + 1 + range_to_move, o_end + 1, len);
325 }
326
327 /* Insert start entry */
328 if (start_ext->ee_len)
329 o_start[i++].ee_len = start_ext->ee_len;
330
331 /* Insert new entry */
332 if (new_ext->ee_len) {
333 o_start[i] = *new_ext;
334 ext4_ext_store_pblock(&o_start[i++], ext4_ext_pblock(new_ext));
335 }
336
337 /* Insert end entry */
338 if (end_ext->ee_len)
339 o_start[i] = *end_ext;
340
341 /* Increment the total entries counter on the extent block */
342 le16_add_cpu(&eh->eh_entries, range_to_move);
343 }
344
345 /**
346 * mext_insert_extents - Insert new extent
347 *
348 * @handle: journal handle
349 * @orig_inode: original inode
350 * @orig_path: path indicates first extent to be changed
351 * @o_start: first original extent to be changed
352 * @o_end: last original extent to be changed
353 * @start_ext: first new extent to be inserted
354 * @new_ext: middle of new extent to be inserted
355 * @end_ext: last new extent to be inserted
356 *
357 * Call the function to insert extents. If we cannot add more extents into
358 * the leaf block, we call mext_insert_across_blocks() to create a
359 * new leaf block. Otherwise call mext_insert_inside_block(). Return 0
360 * on success, or a negative error value on failure.
361 */
362 static int
363 mext_insert_extents(handle_t *handle, struct inode *orig_inode,
364 struct ext4_ext_path *orig_path,
365 struct ext4_extent *o_start,
366 struct ext4_extent *o_end,
367 struct ext4_extent *start_ext,
368 struct ext4_extent *new_ext,
369 struct ext4_extent *end_ext)
370 {
371 struct ext4_extent_header *eh;
372 unsigned long need_slots, slots_range;
373 int range_to_move, depth, ret;
374
375 /*
376 * The extents need to be inserted
377 * start_extent + new_extent + end_extent.
378 */
379 need_slots = (start_ext->ee_len ? 1 : 0) + (end_ext->ee_len ? 1 : 0) +
380 (new_ext->ee_len ? 1 : 0);
381
382 /* The number of slots between start and end */
383 slots_range = ((unsigned long)(o_end + 1) - (unsigned long)o_start + 1)
384 / sizeof(struct ext4_extent);
385
386 /* Range to move the end of extent */
387 range_to_move = need_slots - slots_range;
388 depth = orig_path->p_depth;
389 orig_path += depth;
390 eh = orig_path->p_hdr;
391
392 if (depth) {
393 /* Register to journal */
394 BUFFER_TRACE(orig_path->p_bh, "get_write_access");
395 ret = ext4_journal_get_write_access(handle, orig_path->p_bh);
396 if (ret)
397 return ret;
398 }
399
400 /* Expansion */
401 if (range_to_move > 0 &&
402 (range_to_move > le16_to_cpu(eh->eh_max)
403 - le16_to_cpu(eh->eh_entries))) {
404
405 ret = mext_insert_across_blocks(handle, orig_inode, o_start,
406 o_end, start_ext, new_ext, end_ext);
407 if (ret < 0)
408 return ret;
409 } else
410 mext_insert_inside_block(o_start, o_end, start_ext, new_ext,
411 end_ext, eh, range_to_move);
412
413 return ext4_ext_dirty(handle, orig_inode, orig_path);
414 }
415
416 /**
417 * mext_leaf_block - Move one leaf extent block into the inode.
418 *
419 * @handle: journal handle
420 * @orig_inode: original inode
421 * @orig_path: path indicates first extent to be changed
422 * @dext: donor extent
423 * @from: start offset on the target file
424 *
425 * In order to insert extents into the leaf block, we must divide the extent
426 * in the leaf block into three extents. The one is located to be inserted
427 * extents, and the others are located around it.
428 *
429 * Therefore, this function creates structures to save extents of the leaf
430 * block, and inserts extents by calling mext_insert_extents() with
431 * created extents. Return 0 on success, or a negative error value on failure.
432 */
433 static int
434 mext_leaf_block(handle_t *handle, struct inode *orig_inode,
435 struct ext4_ext_path *orig_path, struct ext4_extent *dext,
436 ext4_lblk_t *from)
437 {
438 struct ext4_extent *oext, *o_start, *o_end, *prev_ext;
439 struct ext4_extent new_ext, start_ext, end_ext;
440 ext4_lblk_t new_ext_end;
441 int oext_alen, new_ext_alen, end_ext_alen;
442 int depth = ext_depth(orig_inode);
443 int ret;
444
445 start_ext.ee_block = end_ext.ee_block = 0;
446 o_start = o_end = oext = orig_path[depth].p_ext;
447 oext_alen = ext4_ext_get_actual_len(oext);
448 start_ext.ee_len = end_ext.ee_len = 0;
449
450 new_ext.ee_block = cpu_to_le32(*from);
451 ext4_ext_store_pblock(&new_ext, ext4_ext_pblock(dext));
452 new_ext.ee_len = dext->ee_len;
453 new_ext_alen = ext4_ext_get_actual_len(&new_ext);
454 new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1;
455
456 /*
457 * Case: original extent is first
458 * oext |--------|
459 * new_ext |--|
460 * start_ext |--|
461 */
462 if (le32_to_cpu(oext->ee_block) < le32_to_cpu(new_ext.ee_block) &&
463 le32_to_cpu(new_ext.ee_block) <
464 le32_to_cpu(oext->ee_block) + oext_alen) {
465 start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
466 le32_to_cpu(oext->ee_block));
467 start_ext.ee_block = oext->ee_block;
468 copy_extent_status(oext, &start_ext);
469 } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
470 prev_ext = oext - 1;
471 /*
472 * We can merge new_ext into previous extent,
473 * if these are contiguous and same extent type.
474 */
475 if (ext4_can_extents_be_merged(orig_inode, prev_ext,
476 &new_ext)) {
477 o_start = prev_ext;
478 start_ext.ee_len = cpu_to_le16(
479 ext4_ext_get_actual_len(prev_ext) +
480 new_ext_alen);
481 start_ext.ee_block = oext->ee_block;
482 copy_extent_status(prev_ext, &start_ext);
483 new_ext.ee_len = 0;
484 }
485 }
486
487 /*
488 * Case: new_ext_end must be less than oext
489 * oext |-----------|
490 * new_ext |-------|
491 */
492 if (le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end) {
493 EXT4_ERROR_INODE(orig_inode,
494 "new_ext_end(%u) should be less than or equal to "
495 "oext->ee_block(%u) + oext_alen(%d) - 1",
496 new_ext_end, le32_to_cpu(oext->ee_block),
497 oext_alen);
498 ret = -EIO;
499 goto out;
500 }
501
502 /*
503 * Case: new_ext is smaller than original extent
504 * oext |---------------|
505 * new_ext |-----------|
506 * end_ext |---|
507 */
508 if (le32_to_cpu(oext->ee_block) <= new_ext_end &&
509 new_ext_end < le32_to_cpu(oext->ee_block) + oext_alen - 1) {
510 end_ext.ee_len =
511 cpu_to_le16(le32_to_cpu(oext->ee_block) +
512 oext_alen - 1 - new_ext_end);
513 copy_extent_status(oext, &end_ext);
514 end_ext_alen = ext4_ext_get_actual_len(&end_ext);
515 ext4_ext_store_pblock(&end_ext,
516 (ext4_ext_pblock(o_end) + oext_alen - end_ext_alen));
517 end_ext.ee_block =
518 cpu_to_le32(le32_to_cpu(o_end->ee_block) +
519 oext_alen - end_ext_alen);
520 }
521
522 ret = mext_insert_extents(handle, orig_inode, orig_path, o_start,
523 o_end, &start_ext, &new_ext, &end_ext);
524 out:
525 return ret;
526 }
527
528 /**
529 * mext_calc_swap_extents - Calculate extents for extent swapping.
530 *
531 * @tmp_dext: the extent that will belong to the original inode
532 * @tmp_oext: the extent that will belong to the donor inode
533 * @orig_off: block offset of original inode
534 * @donor_off: block offset of donor inode
535 * @max_count: the maximum length of extents
536 *
537 * Return 0 on success, or a negative error value on failure.
538 */
539 static int
540 mext_calc_swap_extents(struct ext4_extent *tmp_dext,
541 struct ext4_extent *tmp_oext,
542 ext4_lblk_t orig_off, ext4_lblk_t donor_off,
543 ext4_lblk_t max_count)
544 {
545 ext4_lblk_t diff, orig_diff;
546 struct ext4_extent dext_old, oext_old;
547
548 BUG_ON(orig_off != donor_off);
549
550 /* original and donor extents have to cover the same block offset */
551 if (orig_off < le32_to_cpu(tmp_oext->ee_block) ||
552 le32_to_cpu(tmp_oext->ee_block) +
553 ext4_ext_get_actual_len(tmp_oext) - 1 < orig_off)
554 return -ENODATA;
555
556 if (orig_off < le32_to_cpu(tmp_dext->ee_block) ||
557 le32_to_cpu(tmp_dext->ee_block) +
558 ext4_ext_get_actual_len(tmp_dext) - 1 < orig_off)
559 return -ENODATA;
560
561 dext_old = *tmp_dext;
562 oext_old = *tmp_oext;
563
564 /* When tmp_dext is too large, pick up the target range. */
565 diff = donor_off - le32_to_cpu(tmp_dext->ee_block);
566
567 ext4_ext_store_pblock(tmp_dext, ext4_ext_pblock(tmp_dext) + diff);
568 le32_add_cpu(&tmp_dext->ee_block, diff);
569 le16_add_cpu(&tmp_dext->ee_len, -diff);
570
571 if (max_count < ext4_ext_get_actual_len(tmp_dext))
572 tmp_dext->ee_len = cpu_to_le16(max_count);
573
574 orig_diff = orig_off - le32_to_cpu(tmp_oext->ee_block);
575 ext4_ext_store_pblock(tmp_oext, ext4_ext_pblock(tmp_oext) + orig_diff);
576
577 /* Adjust extent length if donor extent is larger than orig */
578 if (ext4_ext_get_actual_len(tmp_dext) >
579 ext4_ext_get_actual_len(tmp_oext) - orig_diff)
580 tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_oext->ee_len) -
581 orig_diff);
582
583 tmp_oext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(tmp_dext));
584
585 copy_extent_status(&oext_old, tmp_dext);
586 copy_extent_status(&dext_old, tmp_oext);
587
588 return 0;
589 }
590
591 /**
592 * mext_check_coverage - Check that all extents in range has the same type
593 *
594 * @inode: inode in question
595 * @from: block offset of inode
596 * @count: block count to be checked
597 * @unwritten: extents expected to be unwritten
598 * @err: pointer to save error value
599 *
600 * Return 1 if all extents in range has expected type, and zero otherwise.
601 */
602 static int
603 mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
604 int unwritten, int *err)
605 {
606 struct ext4_ext_path *path = NULL;
607 struct ext4_extent *ext;
608 int ret = 0;
609 ext4_lblk_t last = from + count;
610 while (from < last) {
611 *err = get_ext_path(inode, from, &path);
612 if (*err)
613 goto out;
614 ext = path[ext_depth(inode)].p_ext;
615 if (unwritten != ext4_ext_is_unwritten(ext))
616 goto out;
617 from += ext4_ext_get_actual_len(ext);
618 ext4_ext_drop_refs(path);
619 }
620 ret = 1;
621 out:
622 if (path) {
623 ext4_ext_drop_refs(path);
624 kfree(path);
625 }
626 return ret;
627 }
628
629 /**
630 * mext_replace_branches - Replace original extents with new extents
631 *
632 * @handle: journal handle
633 * @orig_inode: original inode
634 * @donor_inode: donor inode
635 * @from: block offset of orig_inode
636 * @count: block count to be replaced
637 * @err: pointer to save return value
638 *
639 * Replace original inode extents and donor inode extents page by page.
640 * We implement this replacement in the following three steps:
641 * 1. Save the block information of original and donor inodes into
642 * dummy extents.
643 * 2. Change the block information of original inode to point at the
644 * donor inode blocks.
645 * 3. Change the block information of donor inode to point at the saved
646 * original inode blocks in the dummy extents.
647 *
648 * Return replaced block count.
649 */
650 static int
651 mext_replace_branches(handle_t *handle, struct inode *orig_inode,
652 struct inode *donor_inode, ext4_lblk_t from,
653 ext4_lblk_t count, int *err)
654 {
655 struct ext4_ext_path *orig_path = NULL;
656 struct ext4_ext_path *donor_path = NULL;
657 struct ext4_extent *oext, *dext;
658 struct ext4_extent tmp_dext, tmp_oext;
659 ext4_lblk_t orig_off = from, donor_off = from;
660 int depth;
661 int replaced_count = 0;
662 int dext_alen;
663
664 *err = ext4_es_remove_extent(orig_inode, from, count);
665 if (*err)
666 goto out;
667
668 *err = ext4_es_remove_extent(donor_inode, from, count);
669 if (*err)
670 goto out;
671
672 /* Get the original extent for the block "orig_off" */
673 *err = get_ext_path(orig_inode, orig_off, &orig_path);
674 if (*err)
675 goto out;
676
677 /* Get the donor extent for the head */
678 *err = get_ext_path(donor_inode, donor_off, &donor_path);
679 if (*err)
680 goto out;
681 depth = ext_depth(orig_inode);
682 oext = orig_path[depth].p_ext;
683 tmp_oext = *oext;
684
685 depth = ext_depth(donor_inode);
686 dext = donor_path[depth].p_ext;
687 if (unlikely(!dext))
688 goto missing_donor_extent;
689 tmp_dext = *dext;
690
691 *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
692 donor_off, count);
693 if (*err)
694 goto out;
695
696 /* Loop for the donor extents */
697 while (1) {
698 /* The extent for donor must be found. */
699 if (unlikely(!dext)) {
700 missing_donor_extent:
701 EXT4_ERROR_INODE(donor_inode,
702 "The extent for donor must be found");
703 *err = -EIO;
704 goto out;
705 } else if (donor_off != le32_to_cpu(tmp_dext.ee_block)) {
706 EXT4_ERROR_INODE(donor_inode,
707 "Donor offset(%u) and the first block of donor "
708 "extent(%u) should be equal",
709 donor_off,
710 le32_to_cpu(tmp_dext.ee_block));
711 *err = -EIO;
712 goto out;
713 }
714
715 /* Set donor extent to orig extent */
716 *err = mext_leaf_block(handle, orig_inode,
717 orig_path, &tmp_dext, &orig_off);
718 if (*err)
719 goto out;
720
721 /* Set orig extent to donor extent */
722 *err = mext_leaf_block(handle, donor_inode,
723 donor_path, &tmp_oext, &donor_off);
724 if (*err)
725 goto out;
726
727 dext_alen = ext4_ext_get_actual_len(&tmp_dext);
728 replaced_count += dext_alen;
729 donor_off += dext_alen;
730 orig_off += dext_alen;
731
732 BUG_ON(replaced_count > count);
733 /* Already moved the expected blocks */
734 if (replaced_count >= count)
735 break;
736
737 if (orig_path)
738 ext4_ext_drop_refs(orig_path);
739 *err = get_ext_path(orig_inode, orig_off, &orig_path);
740 if (*err)
741 goto out;
742 depth = ext_depth(orig_inode);
743 oext = orig_path[depth].p_ext;
744 tmp_oext = *oext;
745
746 if (donor_path)
747 ext4_ext_drop_refs(donor_path);
748 *err = get_ext_path(donor_inode, donor_off, &donor_path);
749 if (*err)
750 goto out;
751 depth = ext_depth(donor_inode);
752 dext = donor_path[depth].p_ext;
753 tmp_dext = *dext;
754
755 *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
756 donor_off, count - replaced_count);
757 if (*err)
758 goto out;
759 }
760
761 out:
762 if (orig_path) {
763 ext4_ext_drop_refs(orig_path);
764 kfree(orig_path);
765 }
766 if (donor_path) {
767 ext4_ext_drop_refs(donor_path);
768 kfree(donor_path);
769 }
770
771 return replaced_count;
772 }
773
774 /**
775 * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
776 *
777 * @inode1: the inode structure
778 * @inode2: the inode structure
779 * @index: page index
780 * @page: result page vector
781 *
782 * Grab two locked pages for inode's by inode order
783 */
784 static int
785 mext_page_double_lock(struct inode *inode1, struct inode *inode2,
786 pgoff_t index, struct page *page[2])
787 {
788 struct address_space *mapping[2];
789 unsigned fl = AOP_FLAG_NOFS;
790
791 BUG_ON(!inode1 || !inode2);
792 if (inode1 < inode2) {
793 mapping[0] = inode1->i_mapping;
794 mapping[1] = inode2->i_mapping;
795 } else {
796 mapping[0] = inode2->i_mapping;
797 mapping[1] = inode1->i_mapping;
798 }
799
800 page[0] = grab_cache_page_write_begin(mapping[0], index, fl);
801 if (!page[0])
802 return -ENOMEM;
803
804 page[1] = grab_cache_page_write_begin(mapping[1], index, fl);
805 if (!page[1]) {
806 unlock_page(page[0]);
807 page_cache_release(page[0]);
808 return -ENOMEM;
809 }
810 /*
811 * grab_cache_page_write_begin() may not wait on page's writeback if
812 * BDI not demand that. But it is reasonable to be very conservative
813 * here and explicitly wait on page's writeback
814 */
815 wait_on_page_writeback(page[0]);
816 wait_on_page_writeback(page[1]);
817 if (inode1 > inode2) {
818 struct page *tmp;
819 tmp = page[0];
820 page[0] = page[1];
821 page[1] = tmp;
822 }
823 return 0;
824 }
825
826 /* Force page buffers uptodate w/o dropping page's lock */
827 static int
828 mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
829 {
830 struct inode *inode = page->mapping->host;
831 sector_t block;
832 struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
833 unsigned int blocksize, block_start, block_end;
834 int i, err, nr = 0, partial = 0;
835 BUG_ON(!PageLocked(page));
836 BUG_ON(PageWriteback(page));
837
838 if (PageUptodate(page))
839 return 0;
840
841 blocksize = 1 << inode->i_blkbits;
842 if (!page_has_buffers(page))
843 create_empty_buffers(page, blocksize, 0);
844
845 head = page_buffers(page);
846 block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
847 for (bh = head, block_start = 0; bh != head || !block_start;
848 block++, block_start = block_end, bh = bh->b_this_page) {
849 block_end = block_start + blocksize;
850 if (block_end <= from || block_start >= to) {
851 if (!buffer_uptodate(bh))
852 partial = 1;
853 continue;
854 }
855 if (buffer_uptodate(bh))
856 continue;
857 if (!buffer_mapped(bh)) {
858 err = ext4_get_block(inode, block, bh, 0);
859 if (err) {
860 SetPageError(page);
861 return err;
862 }
863 if (!buffer_mapped(bh)) {
864 zero_user(page, block_start, blocksize);
865 set_buffer_uptodate(bh);
866 continue;
867 }
868 }
869 BUG_ON(nr >= MAX_BUF_PER_PAGE);
870 arr[nr++] = bh;
871 }
872 /* No io required */
873 if (!nr)
874 goto out;
875
876 for (i = 0; i < nr; i++) {
877 bh = arr[i];
878 if (!bh_uptodate_or_lock(bh)) {
879 err = bh_submit_read(bh);
880 if (err)
881 return err;
882 }
883 }
884 out:
885 if (!partial)
886 SetPageUptodate(page);
887 return 0;
888 }
889
890 /**
891 * move_extent_per_page - Move extent data per page
892 *
893 * @o_filp: file structure of original file
894 * @donor_inode: donor inode
895 * @orig_page_offset: page index on original file
896 * @data_offset_in_page: block index where data swapping starts
897 * @block_len_in_page: the number of blocks to be swapped
898 * @unwritten: orig extent is unwritten or not
899 * @err: pointer to save return value
900 *
901 * Save the data in original inode blocks and replace original inode extents
902 * with donor inode extents by calling mext_replace_branches().
903 * Finally, write out the saved data in new original inode blocks. Return
904 * replaced block count.
905 */
906 static int
907 move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
908 pgoff_t orig_page_offset, int data_offset_in_page,
909 int block_len_in_page, int unwritten, int *err)
910 {
911 struct inode *orig_inode = file_inode(o_filp);
912 struct page *pagep[2] = {NULL, NULL};
913 handle_t *handle;
914 ext4_lblk_t orig_blk_offset;
915 unsigned long blocksize = orig_inode->i_sb->s_blocksize;
916 unsigned int w_flags = 0;
917 unsigned int tmp_data_size, data_size, replaced_size;
918 int err2, jblocks, retries = 0;
919 int replaced_count = 0;
920 int from = data_offset_in_page << orig_inode->i_blkbits;
921 int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
922
923 /*
924 * It needs twice the amount of ordinary journal buffers because
925 * inode and donor_inode may change each different metadata blocks.
926 */
927 again:
928 *err = 0;
929 jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
930 handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks);
931 if (IS_ERR(handle)) {
932 *err = PTR_ERR(handle);
933 return 0;
934 }
935
936 if (segment_eq(get_fs(), KERNEL_DS))
937 w_flags |= AOP_FLAG_UNINTERRUPTIBLE;
938
939 orig_blk_offset = orig_page_offset * blocks_per_page +
940 data_offset_in_page;
941
942 /* Calculate data_size */
943 if ((orig_blk_offset + block_len_in_page - 1) ==
944 ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
945 /* Replace the last block */
946 tmp_data_size = orig_inode->i_size & (blocksize - 1);
947 /*
948 * If data_size equal zero, it shows data_size is multiples of
949 * blocksize. So we set appropriate value.
950 */
951 if (tmp_data_size == 0)
952 tmp_data_size = blocksize;
953
954 data_size = tmp_data_size +
955 ((block_len_in_page - 1) << orig_inode->i_blkbits);
956 } else
957 data_size = block_len_in_page << orig_inode->i_blkbits;
958
959 replaced_size = data_size;
960
961 *err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset,
962 pagep);
963 if (unlikely(*err < 0))
964 goto stop_journal;
965 /*
966 * If orig extent was unwritten it can become initialized
967 * at any time after i_data_sem was dropped, in order to
968 * serialize with delalloc we have recheck extent while we
969 * hold page's lock, if it is still the case data copy is not
970 * necessary, just swap data blocks between orig and donor.
971 */
972 if (unwritten) {
973 ext4_double_down_write_data_sem(orig_inode, donor_inode);
974 /* If any of extents in range became initialized we have to
975 * fallback to data copying */
976 unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
977 block_len_in_page, 1, err);
978 if (*err)
979 goto drop_data_sem;
980
981 unwritten &= mext_check_coverage(donor_inode, orig_blk_offset,
982 block_len_in_page, 1, err);
983 if (*err)
984 goto drop_data_sem;
985
986 if (!unwritten) {
987 ext4_double_up_write_data_sem(orig_inode, donor_inode);
988 goto data_copy;
989 }
990 if ((page_has_private(pagep[0]) &&
991 !try_to_release_page(pagep[0], 0)) ||
992 (page_has_private(pagep[1]) &&
993 !try_to_release_page(pagep[1], 0))) {
994 *err = -EBUSY;
995 goto drop_data_sem;
996 }
997 replaced_count = mext_replace_branches(handle, orig_inode,
998 donor_inode, orig_blk_offset,
999 block_len_in_page, err);
1000 drop_data_sem:
1001 ext4_double_up_write_data_sem(orig_inode, donor_inode);
1002 goto unlock_pages;
1003 }
1004 data_copy:
1005 *err = mext_page_mkuptodate(pagep[0], from, from + replaced_size);
1006 if (*err)
1007 goto unlock_pages;
1008
1009 /* At this point all buffers in range are uptodate, old mapping layout
1010 * is no longer required, try to drop it now. */
1011 if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) ||
1012 (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) {
1013 *err = -EBUSY;
1014 goto unlock_pages;
1015 }
1016
1017 replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
1018 orig_blk_offset,
1019 block_len_in_page, err);
1020 if (*err) {
1021 if (replaced_count) {
1022 block_len_in_page = replaced_count;
1023 replaced_size =
1024 block_len_in_page << orig_inode->i_blkbits;
1025 } else
1026 goto unlock_pages;
1027 }
1028 /* Perform all necessary steps similar write_begin()/write_end()
1029 * but keeping in mind that i_size will not change */
1030 *err = __block_write_begin(pagep[0], from, replaced_size,
1031 ext4_get_block);
1032 if (!*err)
1033 *err = block_commit_write(pagep[0], from, from + replaced_size);
1034
1035 if (unlikely(*err < 0))
1036 goto repair_branches;
1037
1038 /* Even in case of data=writeback it is reasonable to pin
1039 * inode to transaction, to prevent unexpected data loss */
1040 *err = ext4_jbd2_file_inode(handle, orig_inode);
1041
1042 unlock_pages:
1043 unlock_page(pagep[0]);
1044 page_cache_release(pagep[0]);
1045 unlock_page(pagep[1]);
1046 page_cache_release(pagep[1]);
1047 stop_journal:
1048 ext4_journal_stop(handle);
1049 /* Buffer was busy because probably is pinned to journal transaction,
1050 * force transaction commit may help to free it. */
1051 if (*err == -EBUSY && ext4_should_retry_alloc(orig_inode->i_sb,
1052 &retries))
1053 goto again;
1054 return replaced_count;
1055
1056 repair_branches:
1057 /*
1058 * This should never ever happen!
1059 * Extents are swapped already, but we are not able to copy data.
1060 * Try to swap extents to it's original places
1061 */
1062 ext4_double_down_write_data_sem(orig_inode, donor_inode);
1063 replaced_count = mext_replace_branches(handle, donor_inode, orig_inode,
1064 orig_blk_offset,
1065 block_len_in_page, &err2);
1066 ext4_double_up_write_data_sem(orig_inode, donor_inode);
1067 if (replaced_count != block_len_in_page) {
1068 EXT4_ERROR_INODE_BLOCK(orig_inode, (sector_t)(orig_blk_offset),
1069 "Unable to copy data block,"
1070 " data will be lost.");
1071 *err = -EIO;
1072 }
1073 replaced_count = 0;
1074 goto unlock_pages;
1075 }
1076
1077 /**
1078 * mext_check_arguments - Check whether move extent can be done
1079 *
1080 * @orig_inode: original inode
1081 * @donor_inode: donor inode
1082 * @orig_start: logical start offset in block for orig
1083 * @donor_start: logical start offset in block for donor
1084 * @len: the number of blocks to be moved
1085 *
1086 * Check the arguments of ext4_move_extents() whether the files can be
1087 * exchanged with each other.
1088 * Return 0 on success, or a negative error value on failure.
1089 */
1090 static int
1091 mext_check_arguments(struct inode *orig_inode,
1092 struct inode *donor_inode, __u64 orig_start,
1093 __u64 donor_start, __u64 *len)
1094 {
1095 ext4_lblk_t orig_blocks, donor_blocks;
1096 unsigned int blkbits = orig_inode->i_blkbits;
1097 unsigned int blocksize = 1 << blkbits;
1098
1099 if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
1100 ext4_debug("ext4 move extent: suid or sgid is set"
1101 " to donor file [ino:orig %lu, donor %lu]\n",
1102 orig_inode->i_ino, donor_inode->i_ino);
1103 return -EINVAL;
1104 }
1105
1106 if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
1107 return -EPERM;
1108
1109 /* Ext4 move extent does not support swapfile */
1110 if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
1111 ext4_debug("ext4 move extent: The argument files should "
1112 "not be swapfile [ino:orig %lu, donor %lu]\n",
1113 orig_inode->i_ino, donor_inode->i_ino);
1114 return -EINVAL;
1115 }
1116
1117 /* Ext4 move extent supports only extent based file */
1118 if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
1119 ext4_debug("ext4 move extent: orig file is not extents "
1120 "based file [ino:orig %lu]\n", orig_inode->i_ino);
1121 return -EOPNOTSUPP;
1122 } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
1123 ext4_debug("ext4 move extent: donor file is not extents "
1124 "based file [ino:donor %lu]\n", donor_inode->i_ino);
1125 return -EOPNOTSUPP;
1126 }
1127
1128 if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
1129 ext4_debug("ext4 move extent: File size is 0 byte\n");
1130 return -EINVAL;
1131 }
1132
1133 /* Start offset should be same */
1134 if (orig_start != donor_start) {
1135 ext4_debug("ext4 move extent: orig and donor's start "
1136 "offset are not same [ino:orig %lu, donor %lu]\n",
1137 orig_inode->i_ino, donor_inode->i_ino);
1138 return -EINVAL;
1139 }
1140
1141 if ((orig_start >= EXT_MAX_BLOCKS) ||
1142 (*len > EXT_MAX_BLOCKS) ||
1143 (orig_start + *len >= EXT_MAX_BLOCKS)) {
1144 ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
1145 "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
1146 orig_inode->i_ino, donor_inode->i_ino);
1147 return -EINVAL;
1148 }
1149
1150 if (orig_inode->i_size > donor_inode->i_size) {
1151 donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits;
1152 /* TODO: eliminate this artificial restriction */
1153 if (orig_start >= donor_blocks) {
1154 ext4_debug("ext4 move extent: orig start offset "
1155 "[%llu] should be less than donor file blocks "
1156 "[%u] [ino:orig %lu, donor %lu]\n",
1157 orig_start, donor_blocks,
1158 orig_inode->i_ino, donor_inode->i_ino);
1159 return -EINVAL;
1160 }
1161
1162 /* TODO: eliminate this artificial restriction */
1163 if (orig_start + *len > donor_blocks) {
1164 ext4_debug("ext4 move extent: End offset [%llu] should "
1165 "be less than donor file blocks [%u]."
1166 "So adjust length from %llu to %llu "
1167 "[ino:orig %lu, donor %lu]\n",
1168 orig_start + *len, donor_blocks,
1169 *len, donor_blocks - orig_start,
1170 orig_inode->i_ino, donor_inode->i_ino);
1171 *len = donor_blocks - orig_start;
1172 }
1173 } else {
1174 orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits;
1175 if (orig_start >= orig_blocks) {
1176 ext4_debug("ext4 move extent: start offset [%llu] "
1177 "should be less than original file blocks "
1178 "[%u] [ino:orig %lu, donor %lu]\n",
1179 orig_start, orig_blocks,
1180 orig_inode->i_ino, donor_inode->i_ino);
1181 return -EINVAL;
1182 }
1183
1184 if (orig_start + *len > orig_blocks) {
1185 ext4_debug("ext4 move extent: Adjust length "
1186 "from %llu to %llu. Because it should be "
1187 "less than original file blocks "
1188 "[ino:orig %lu, donor %lu]\n",
1189 *len, orig_blocks - orig_start,
1190 orig_inode->i_ino, donor_inode->i_ino);
1191 *len = orig_blocks - orig_start;
1192 }
1193 }
1194
1195 if (!*len) {
1196 ext4_debug("ext4 move extent: len should not be 0 "
1197 "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
1198 donor_inode->i_ino);
1199 return -EINVAL;
1200 }
1201
1202 return 0;
1203 }
1204
1205 /**
1206 * ext4_move_extents - Exchange the specified range of a file
1207 *
1208 * @o_filp: file structure of the original file
1209 * @d_filp: file structure of the donor file
1210 * @orig_start: start offset in block for orig
1211 * @donor_start: start offset in block for donor
1212 * @len: the number of blocks to be moved
1213 * @moved_len: moved block length
1214 *
1215 * This function returns 0 and moved block length is set in moved_len
1216 * if succeed, otherwise returns error value.
1217 *
1218 * Note: ext4_move_extents() proceeds the following order.
1219 * 1:ext4_move_extents() calculates the last block number of moving extent
1220 * function by the start block number (orig_start) and the number of blocks
1221 * to be moved (len) specified as arguments.
1222 * If the {orig, donor}_start points a hole, the extent's start offset
1223 * pointed by ext_cur (current extent), holecheck_path, orig_path are set
1224 * after hole behind.
1225 * 2:Continue step 3 to step 5, until the holecheck_path points to last_extent
1226 * or the ext_cur exceeds the block_end which is last logical block number.
1227 * 3:To get the length of continues area, call mext_next_extent()
1228 * specified with the ext_cur (initial value is holecheck_path) re-cursive,
1229 * until find un-continuous extent, the start logical block number exceeds
1230 * the block_end or the extent points to the last extent.
1231 * 4:Exchange the original inode data with donor inode data
1232 * from orig_page_offset to seq_end_page.
1233 * The start indexes of data are specified as arguments.
1234 * That of the original inode is orig_page_offset,
1235 * and the donor inode is also orig_page_offset
1236 * (To easily handle blocksize != pagesize case, the offset for the
1237 * donor inode is block unit).
1238 * 5:Update holecheck_path and orig_path to points a next proceeding extent,
1239 * then returns to step 2.
1240 * 6:Release holecheck_path, orig_path and set the len to moved_len
1241 * which shows the number of moved blocks.
1242 * The moved_len is useful for the command to calculate the file offset
1243 * for starting next move extent ioctl.
1244 * 7:Return 0 on success, or a negative error value on failure.
1245 */
1246 int
1247 ext4_move_extents(struct file *o_filp, struct file *d_filp,
1248 __u64 orig_start, __u64 donor_start, __u64 len,
1249 __u64 *moved_len)
1250 {
1251 struct inode *orig_inode = file_inode(o_filp);
1252 struct inode *donor_inode = file_inode(d_filp);
1253 struct ext4_ext_path *orig_path = NULL, *holecheck_path = NULL;
1254 struct ext4_extent *ext_prev, *ext_cur, *ext_dummy;
1255 ext4_lblk_t block_start = orig_start;
1256 ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0;
1257 ext4_lblk_t rest_blocks;
1258 pgoff_t orig_page_offset = 0, seq_end_page;
1259 int ret, depth, last_extent = 0;
1260 int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
1261 int data_offset_in_page;
1262 int block_len_in_page;
1263 int unwritten;
1264
1265 if (orig_inode->i_sb != donor_inode->i_sb) {
1266 ext4_debug("ext4 move extent: The argument files "
1267 "should be in same FS [ino:orig %lu, donor %lu]\n",
1268 orig_inode->i_ino, donor_inode->i_ino);
1269 return -EINVAL;
1270 }
1271
1272 /* orig and donor should be different inodes */
1273 if (orig_inode == donor_inode) {
1274 ext4_debug("ext4 move extent: The argument files should not "
1275 "be same inode [ino:orig %lu, donor %lu]\n",
1276 orig_inode->i_ino, donor_inode->i_ino);
1277 return -EINVAL;
1278 }
1279
1280 /* Regular file check */
1281 if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
1282 ext4_debug("ext4 move extent: The argument files should be "
1283 "regular file [ino:orig %lu, donor %lu]\n",
1284 orig_inode->i_ino, donor_inode->i_ino);
1285 return -EINVAL;
1286 }
1287 /* TODO: This is non obvious task to swap blocks for inodes with full
1288 jornaling enabled */
1289 if (ext4_should_journal_data(orig_inode) ||
1290 ext4_should_journal_data(donor_inode)) {
1291 return -EINVAL;
1292 }
1293 /* Protect orig and donor inodes against a truncate */
1294 lock_two_nondirectories(orig_inode, donor_inode);
1295
1296 /* Wait for all existing dio workers */
1297 ext4_inode_block_unlocked_dio(orig_inode);
1298 ext4_inode_block_unlocked_dio(donor_inode);
1299 inode_dio_wait(orig_inode);
1300 inode_dio_wait(donor_inode);
1301
1302 /* Protect extent tree against block allocations via delalloc */
1303 ext4_double_down_write_data_sem(orig_inode, donor_inode);
1304 /* Check the filesystem environment whether move_extent can be done */
1305 ret = mext_check_arguments(orig_inode, donor_inode, orig_start,
1306 donor_start, &len);
1307 if (ret)
1308 goto out;
1309
1310 file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;
1311 block_end = block_start + len - 1;
1312 if (file_end < block_end)
1313 len -= block_end - file_end;
1314
1315 ret = get_ext_path(orig_inode, block_start, &orig_path);
1316 if (ret)
1317 goto out;
1318
1319 /* Get path structure to check the hole */
1320 ret = get_ext_path(orig_inode, block_start, &holecheck_path);
1321 if (ret)
1322 goto out;
1323
1324 depth = ext_depth(orig_inode);
1325 ext_cur = holecheck_path[depth].p_ext;
1326
1327 /*
1328 * Get proper starting location of block replacement if block_start was
1329 * within the hole.
1330 */
1331 if (le32_to_cpu(ext_cur->ee_block) +
1332 ext4_ext_get_actual_len(ext_cur) - 1 < block_start) {
1333 /*
1334 * The hole exists between extents or the tail of
1335 * original file.
1336 */
1337 last_extent = mext_next_extent(orig_inode,
1338 holecheck_path, &ext_cur);
1339 if (last_extent < 0) {
1340 ret = last_extent;
1341 goto out;
1342 }
1343 last_extent = mext_next_extent(orig_inode, orig_path,
1344 &ext_dummy);
1345 if (last_extent < 0) {
1346 ret = last_extent;
1347 goto out;
1348 }
1349 seq_start = le32_to_cpu(ext_cur->ee_block);
1350 } else if (le32_to_cpu(ext_cur->ee_block) > block_start)
1351 /* The hole exists at the beginning of original file. */
1352 seq_start = le32_to_cpu(ext_cur->ee_block);
1353 else
1354 seq_start = block_start;
1355
1356 /* No blocks within the specified range. */
1357 if (le32_to_cpu(ext_cur->ee_block) > block_end) {
1358 ext4_debug("ext4 move extent: The specified range of file "
1359 "may be the hole\n");
1360 ret = -EINVAL;
1361 goto out;
1362 }
1363
1364 /* Adjust start blocks */
1365 add_blocks = min(le32_to_cpu(ext_cur->ee_block) +
1366 ext4_ext_get_actual_len(ext_cur), block_end + 1) -
1367 max(le32_to_cpu(ext_cur->ee_block), block_start);
1368
1369 while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) {
1370 seq_blocks += add_blocks;
1371
1372 /* Adjust tail blocks */
1373 if (seq_start + seq_blocks - 1 > block_end)
1374 seq_blocks = block_end - seq_start + 1;
1375
1376 ext_prev = ext_cur;
1377 last_extent = mext_next_extent(orig_inode, holecheck_path,
1378 &ext_cur);
1379 if (last_extent < 0) {
1380 ret = last_extent;
1381 break;
1382 }
1383 add_blocks = ext4_ext_get_actual_len(ext_cur);
1384
1385 /*
1386 * Extend the length of contiguous block (seq_blocks)
1387 * if extents are contiguous.
1388 */
1389 if (ext4_can_extents_be_merged(orig_inode,
1390 ext_prev, ext_cur) &&
1391 block_end >= le32_to_cpu(ext_cur->ee_block) &&
1392 !last_extent)
1393 continue;
1394
1395 /* Is original extent is unwritten */
1396 unwritten = ext4_ext_is_unwritten(ext_prev);
1397
1398 data_offset_in_page = seq_start % blocks_per_page;
1399
1400 /*
1401 * Calculate data blocks count that should be swapped
1402 * at the first page.
1403 */
1404 if (data_offset_in_page + seq_blocks > blocks_per_page) {
1405 /* Swapped blocks are across pages */
1406 block_len_in_page =
1407 blocks_per_page - data_offset_in_page;
1408 } else {
1409 /* Swapped blocks are in a page */
1410 block_len_in_page = seq_blocks;
1411 }
1412
1413 orig_page_offset = seq_start >>
1414 (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
1415 seq_end_page = (seq_start + seq_blocks - 1) >>
1416 (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
1417 seq_start = le32_to_cpu(ext_cur->ee_block);
1418 rest_blocks = seq_blocks;
1419
1420 /*
1421 * Up semaphore to avoid following problems:
1422 * a. transaction deadlock among ext4_journal_start,
1423 * ->write_begin via pagefault, and jbd2_journal_commit
1424 * b. racing with ->readpage, ->write_begin, and ext4_get_block
1425 * in move_extent_per_page
1426 */
1427 ext4_double_up_write_data_sem(orig_inode, donor_inode);
1428
1429 while (orig_page_offset <= seq_end_page) {
1430
1431 /* Swap original branches with new branches */
1432 block_len_in_page = move_extent_per_page(
1433 o_filp, donor_inode,
1434 orig_page_offset,
1435 data_offset_in_page,
1436 block_len_in_page,
1437 unwritten, &ret);
1438
1439 /* Count how many blocks we have exchanged */
1440 *moved_len += block_len_in_page;
1441 if (ret < 0)
1442 break;
1443 if (*moved_len > len) {
1444 EXT4_ERROR_INODE(orig_inode,
1445 "We replaced blocks too much! "
1446 "sum of replaced: %llu requested: %llu",
1447 *moved_len, len);
1448 ret = -EIO;
1449 break;
1450 }
1451
1452 orig_page_offset++;
1453 data_offset_in_page = 0;
1454 rest_blocks -= block_len_in_page;
1455 if (rest_blocks > blocks_per_page)
1456 block_len_in_page = blocks_per_page;
1457 else
1458 block_len_in_page = rest_blocks;
1459 }
1460
1461 ext4_double_down_write_data_sem(orig_inode, donor_inode);
1462 if (ret < 0)
1463 break;
1464
1465 /* Decrease buffer counter */
1466 if (holecheck_path)
1467 ext4_ext_drop_refs(holecheck_path);
1468 ret = get_ext_path(orig_inode, seq_start, &holecheck_path);
1469 if (ret)
1470 break;
1471 depth = holecheck_path->p_depth;
1472
1473 /* Decrease buffer counter */
1474 if (orig_path)
1475 ext4_ext_drop_refs(orig_path);
1476 ret = get_ext_path(orig_inode, seq_start, &orig_path);
1477 if (ret)
1478 break;
1479
1480 ext_cur = holecheck_path[depth].p_ext;
1481 add_blocks = ext4_ext_get_actual_len(ext_cur);
1482 seq_blocks = 0;
1483
1484 }
1485 out:
1486 if (*moved_len) {
1487 ext4_discard_preallocations(orig_inode);
1488 ext4_discard_preallocations(donor_inode);
1489 }
1490
1491 if (orig_path) {
1492 ext4_ext_drop_refs(orig_path);
1493 kfree(orig_path);
1494 }
1495 if (holecheck_path) {
1496 ext4_ext_drop_refs(holecheck_path);
1497 kfree(holecheck_path);
1498 }
1499 ext4_double_up_write_data_sem(orig_inode, donor_inode);
1500 ext4_inode_resume_unlocked_dio(orig_inode);
1501 ext4_inode_resume_unlocked_dio(donor_inode);
1502 unlock_two_nondirectories(orig_inode, donor_inode);
1503
1504 return ret;
1505 }
Linux kernel - Deliverables
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