aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ext4/migrate.c
blob: b9e077ba07e94b0c979ebea4530e1fc9471e6eee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
/*
 * Copyright IBM Corporation, 2007
 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 */

#include <linux/module.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"

/*
 * The contiguous blocks details which can be
 * represented by a single extent
 */
struct list_blocks_struct {
	ext4_lblk_t first_block, last_block;
	ext4_fsblk_t first_pblock, last_pblock;
};

static int finish_range(handle_t *handle, struct inode *inode,
				struct list_blocks_struct *lb)

{
	int retval = 0, needed;
	struct ext4_extent newext;
	struct ext4_ext_path *path;
	if (lb->first_pblock == 0)
		return 0;

	/* Add the extent to temp inode*/
	newext.ee_block = cpu_to_le32(lb->first_block);
	newext.ee_len   = cpu_to_le16(lb->last_block - lb->first_block + 1);
	ext4_ext_store_pblock(&newext, lb->first_pblock);
	path = ext4_ext_find_extent(inode, lb->first_block, NULL);

	if (IS_ERR(path)) {
		retval = PTR_ERR(path);
		path = NULL;
		goto err_out;
	}

	/*
	 * Calculate the credit needed to inserting this extent
	 * Since we are doing this in loop we may accumalate extra
	 * credit. But below we try to not accumalate too much
	 * of them by restarting the journal.
	 */
	needed = ext4_ext_calc_credits_for_insert(inode, path);

	/*
	 * Make sure the credit we accumalated is not really high
	 */
	if (needed && handle->h_buffer_credits >= EXT4_RESERVE_TRANS_BLOCKS) {
		retval = ext4_journal_restart(handle, needed);
		if (retval)
			goto err_out;
	} else if (needed) {
		retval = ext4_journal_extend(handle, needed);
		if (retval) {
			/*
			 * IF not able to extend the journal restart the journal
			 */
			retval = ext4_journal_restart(handle, needed);
			if (retval)
				goto err_out;
		}
	}
	retval = ext4_ext_insert_extent(handle, inode, path, &newext);
err_out:
	if (path) {
		ext4_ext_drop_refs(path);
		kfree(path);
	}
	lb->first_pblock = 0;
	return retval;
}

static int update_extent_range(handle_t *handle, struct inode *inode,
				ext4_fsblk_t pblock, ext4_lblk_t blk_num,
				struct list_blocks_struct *lb)
{
	int retval;
	/*
	 * See if we can add on to the existing range (if it exists)
	 */
	if (lb->first_pblock &&
		(lb->last_pblock+1 == pblock) &&
		(lb->last_block+1 == blk_num)) {
		lb->last_pblock = pblock;
		lb->last_block = blk_num;
		return 0;
	}
	/*
	 * Start a new range.
	 */
	retval = finish_range(handle, inode, lb);
	lb->first_pblock = lb->last_pblock = pblock;
	lb->first_block = lb->last_block = blk_num;

	return retval;
}

static int update_ind_extent_range(handle_t *handle, struct inode *inode,
				   ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
				   struct list_blocks_struct *lb)
{
	struct buffer_head *bh;
	__le32 *i_data;
	int i, retval = 0;
	ext4_lblk_t blk_count = *blk_nump;
	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;

	if (!pblock) {
		/* Only update the file block number */
		*blk_nump += max_entries;
		return 0;
	}

	bh = sb_bread(inode->i_sb, pblock);
	if (!bh)
		return -EIO;

	i_data = (__le32 *)bh->b_data;
	for (i = 0; i < max_entries; i++, blk_count++) {
		if (i_data[i]) {
			retval = update_extent_range(handle, inode,
						le32_to_cpu(i_data[i]),
						blk_count, lb);
			if (retval)
				break;
		}
	}

	/* Update the file block number */
	*blk_nump = blk_count;
	put_bh(bh);
	return retval;

}

static int update_dind_extent_range(handle_t *handle, struct inode *inode,
				    ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
				    struct list_blocks_struct *lb)
{
	struct buffer_head *bh;
	__le32 *i_data;
	int i, retval = 0;
	ext4_lblk_t blk_count = *blk_nump;
	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;

	if (!pblock) {
		/* Only update the file block number */
		*blk_nump += max_entries * max_entries;
		return 0;
	}
	bh = sb_bread(inode->i_sb, pblock);
	if (!bh)
		return -EIO;

	i_data = (__le32 *)bh->b_data;
	for (i = 0; i < max_entries; i++) {
		if (i_data[i]) {
			retval = update_ind_extent_range(handle, inode,
						le32_to_cpu(i_data[i]),
						&blk_count, lb);
			if (retval)
				break;
		} else {
			/* Only update the file block number */
			blk_count += max_entries;
		}
	}

	/* Update the file block number */
	*blk_nump = blk_count;
	put_bh(bh);
	return retval;

}

static int update_tind_extent_range(handle_t *handle, struct inode *inode,
				     ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
				     struct list_blocks_struct *lb)
{
	struct buffer_head *bh;
	__le32 *i_data;
	int i, retval = 0;
	ext4_lblk_t blk_count = *blk_nump;
	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;

	if (!pblock) {
		/* Only update the file block number */
		*blk_nump += max_entries * max_entries * max_entries;
		return 0;
	}
	bh = sb_bread(inode->i_sb, pblock);
	if (!bh)
		return -EIO;

	i_data = (__le32 *)bh->b_data;
	for (i = 0; i < max_entries; i++) {
		if (i_data[i]) {
			retval = update_dind_extent_range(handle, inode,
						le32_to_cpu(i_data[i]),
						&blk_count, lb);
			if (retval)
				break;
		} else
			/* Only update the file block number */
			blk_count += max_entries * max_entries;
	}
	/* Update the file block number */
	*blk_nump = blk_count;
	put_bh(bh);
	return retval;

}

static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode)
{
	int retval = 0, needed;

	if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
		return 0;
	/*
	 * We are freeing a blocks. During this we touch
	 * superblock, group descriptor and block bitmap.
	 * So allocate a credit of 3. We may update
	 * quota (user and group).
	 */
	needed = 3 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);

	if (ext4_journal_extend(handle, needed) != 0)
		retval = ext4_journal_restart(handle, needed);

	return retval;
}

static int free_dind_blocks(handle_t *handle,
				struct inode *inode, __le32 i_data)
{
	int i;
	__le32 *tmp_idata;
	struct buffer_head *bh;
	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;

	bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
	if (!bh)
		return -EIO;

	tmp_idata = (__le32 *)bh->b_data;
	for (i = 0; i < max_entries; i++) {
		if (tmp_idata[i]) {
			extend_credit_for_blkdel(handle, inode);
			ext4_free_blocks(handle, inode,
					le32_to_cpu(tmp_idata[i]), 1, 1);
		}
	}
	put_bh(bh);
	extend_credit_for_blkdel(handle, inode);
	ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
	return 0;
}

static int free_tind_blocks(handle_t *handle,
				struct inode *inode, __le32 i_data)
{
	int i, retval = 0;
	__le32 *tmp_idata;
	struct buffer_head *bh;
	unsigned long max_entries = inode->i_sb->s_blocksize >> 2;

	bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
	if (!bh)
		return -EIO;

	tmp_idata = (__le32 *)bh->b_data;
	for (i = 0; i < max_entries; i++) {
		if (tmp_idata[i]) {
			retval = free_dind_blocks(handle,
					inode, tmp_idata[i]);
			if (retval) {
				put_bh(bh);
				return retval;
			}
		}
	}
	put_bh(bh);
	extend_credit_for_blkdel(handle, inode);
	ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
	return 0;
}

static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
{
	int retval;

	/* ei->i_data[EXT4_IND_BLOCK] */
	if (i_data[0]) {
		extend_credit_for_blkdel(handle, inode);
		ext4_free_blocks(handle, inode,
				le32_to_cpu(i_data[0]), 1, 1);
	}

	/* ei->i_data[EXT4_DIND_BLOCK] */
	if (i_data[1]) {
		retval = free_dind_blocks(handle, inode, i_data[1]);
		if (retval)
			return retval;
	}

	/* ei->i_data[EXT4_TIND_BLOCK] */
	if (i_data[2]) {
		retval = free_tind_blocks(handle, inode, i_data[2]);
		if (retval)
			return retval;
	}
	return 0;
}

static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
						struct inode *tmp_inode)
{
	int retval;
	__le32	i_data[3];
	struct ext4_inode_info *ei = EXT4_I(inode);
	struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);

	/*
	 * One credit accounted for writing the
	 * i_data field of the original inode
	 */
	retval = ext4_journal_extend(handle, 1);
	if (retval) {
		retval = ext4_journal_restart(handle, 1);
		if (retval)
			goto err_out;
	}

	i_data[0] = ei->i_data[EXT4_IND_BLOCK];
	i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
	i_data[2] = ei->i_data[EXT4_TIND_BLOCK];

	down_write(&EXT4_I(inode)->i_data_sem);
	/*
	 * if EXT4_EXT_MIGRATE is cleared a block allocation
	 * happened after we started the migrate. We need to
	 * fail the migrate
	 */
	if (!(EXT4_I(inode)->i_flags & EXT4_EXT_MIGRATE)) {
		retval = -EAGAIN;
		up_write(&EXT4_I(inode)->i_data_sem);
		goto err_out;
	} else
		EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
							~EXT4_EXT_MIGRATE;
	/*
	 * We have the extent map build with the tmp inode.
	 * Now copy the i_data across
	 */
	ei->i_flags |= EXT4_EXTENTS_FL;
	memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));

	/*
	 * Update i_blocks with the new blocks that got
	 * allocated while adding extents for extent index
	 * blocks.
	 *
	 * While converting to extents we need not
	 * update the orignal inode i_blocks for extent blocks
	 * via quota APIs. The quota update happened via tmp_inode already.
	 */
	spin_lock(&inode->i_lock);
	inode->i_blocks += tmp_inode->i_blocks;
	spin_unlock(&inode->i_lock);
	up_write(&EXT4_I(inode)->i_data_sem);

	/*
	 * We mark the inode dirty after, because we decrement the
	 * i_blocks when freeing the indirect meta-data blocks
	 */
	retval = free_ind_block(handle, inode, i_data);
	ext4_mark_inode_dirty(handle, inode);

err_out:
	return retval;
}

static int free_ext_idx(handle_t *handle, struct inode *inode,
					struct ext4_extent_idx *ix)
{
	int i, retval = 0;
	ext4_fsblk_t block;
	struct buffer_head *bh;
	struct ext4_extent_header *eh;

	block = idx_pblock(ix);
	bh = sb_bread(inode->i_sb, block);
	if (!bh)
		return -EIO;

	eh = (struct ext4_extent_header *)bh->b_data;
	if (eh->eh_depth != 0) {
		ix = EXT_FIRST_INDEX(eh);
		for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
			retval = free_ext_idx(handle, inode, ix);
			if (retval)
				break;
		}
	}
	put_bh(bh);
	extend_credit_for_blkdel(handle, inode);
	ext4_free_blocks(handle, inode, block, 1, 1);
	return retval;
}

/*
 * Free the extent meta data blocks only
 */
static int free_ext_block(handle_t *handle, struct inode *inode)
{
	int i, retval = 0;
	struct ext4_inode_info *ei = EXT4_I(inode);
	struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
	struct ext4_extent_idx *ix;
	if (eh->eh_depth == 0)
		/*
		 * No extra blocks allocated for extent meta data
		 */
		return 0;
	ix = EXT_FIRST_INDEX(eh);
	for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
		retval = free_ext_idx(handle, inode, ix);
		if (retval)
			return retval;
	}
	return retval;

}

int ext4_ext_migrate(struct inode *inode, struct file *filp,
				unsigned int cmd, unsigned long arg)
{
	handle_t *handle;
	int retval = 0, i;
	__le32 *i_data;
	ext4_lblk_t blk_count = 0;
	struct ext4_inode_info *ei;
	struct inode *tmp_inode = NULL;
	struct list_blocks_struct lb;
	unsigned long max_entries;

	if (!test_opt(inode->i_sb, EXTENTS))
		/*
		 * if mounted with noextents we don't allow the migrate
		 */
		return -EINVAL;

	if ((EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
		return -EINVAL;

	if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
		/*
		 * don't migrate fast symlink
		 */
		return retval;

	handle = ext4_journal_start(inode,
					EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
					EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
					2 * EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)
					+ 1);
	if (IS_ERR(handle)) {
		retval = PTR_ERR(handle);
		goto err_out;
	}
	tmp_inode = ext4_new_inode(handle,
				inode->i_sb->s_root->d_inode,
				S_IFREG);
	if (IS_ERR(tmp_inode)) {
		retval = -ENOMEM;
		ext4_journal_stop(handle);
		tmp_inode = NULL;
		goto err_out;
	}
	i_size_write(tmp_inode, i_size_read(inode));
	/*
	 * We don't want the inode to be reclaimed
	 * if we got interrupted in between. We have
	 * this tmp inode carrying reference to the
	 * data blocks of the original file. We set
	 * the i_nlink to zero at the last stage after
	 * switching the original file to extent format
	 */
	tmp_inode->i_nlink = 1;

	ext4_ext_tree_init(handle, tmp_inode);
	ext4_orphan_add(handle, tmp_inode);
	ext4_journal_stop(handle);

	/*
	 * start with one credit accounted for
	 * superblock modification.
	 *
	 * For the tmp_inode we already have commited the
	 * trascation that created the inode. Later as and
	 * when we add extents we extent the journal
	 */
	/*
	 * inode_mutex prevent write and truncate on the file. Read still goes
	 * through. We take i_data_sem in ext4_ext_swap_inode_data before we
	 * switch the inode format to prevent read.
	 */
	mutex_lock(&(inode->i_mutex));
	/*
	 * Even though we take i_mutex we can still cause block allocation
	 * via mmap write to holes. If we have allocated new blocks we fail
	 * migrate.  New block allocation will clear EXT4_EXT_MIGRATE flag.
	 * The flag is updated with i_data_sem held to prevent racing with
	 * block allocation.
	 */
	down_read((&EXT4_I(inode)->i_data_sem));
	EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags | EXT4_EXT_MIGRATE;
	up_read((&EXT4_I(inode)->i_data_sem));

	handle = ext4_journal_start(inode, 1);

	ei = EXT4_I(inode);
	i_data = ei->i_data;
	memset(&lb, 0, sizeof(lb));

	/* 32 bit block address 4 bytes */
	max_entries = inode->i_sb->s_blocksize >> 2;
	for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) {
		if (i_data[i]) {
			retval = update_extent_range(handle, tmp_inode,
						le32_to_cpu(i_data[i]),
						blk_count, &lb);
			if (retval)
				goto err_out;
		}
	}
	if (i_data[EXT4_IND_BLOCK]) {
		retval = update_ind_extent_range(handle, tmp_inode,
					le32_to_cpu(i_data[EXT4_IND_BLOCK]),
					&blk_count, &lb);
			if (retval)
				goto err_out;
	} else
		blk_count +=  max_entries;
	if (i_data[EXT4_DIND_BLOCK]) {
		retval = update_dind_extent_range(handle, tmp_inode,
					le32_to_cpu(i_data[EXT4_DIND_BLOCK]),
					&blk_count, &lb);
			if (retval)
				goto err_out;
	} else
		blk_count += max_entries * max_entries;
	if (i_data[EXT4_TIND_BLOCK]) {
		retval = update_tind_extent_range(handle, tmp_inode,
					le32_to_cpu(i_data[EXT4_TIND_BLOCK]),
					&blk_count, &lb);
			if (retval)
				goto err_out;
	}
	/*
	 * Build the last extent
	 */
	retval = finish_range(handle, tmp_inode, &lb);
err_out:
	if (retval)
		/*
		 * Failure case delete the extent information with the
		 * tmp_inode
		 */
		free_ext_block(handle, tmp_inode);
	else {
		retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
		if (retval)
			/*
			 * if we fail to swap inode data free the extent
			 * details of the tmp inode
			 */
			free_ext_block(handle, tmp_inode);
	}

	/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
	if (ext4_journal_extend(handle, 1) != 0)
		ext4_journal_restart(handle, 1);

	/*
	 * Mark the tmp_inode as of size zero
	 */
	i_size_write(tmp_inode, 0);

	/*
	 * set the  i_blocks count to zero
	 * so that the ext4_delete_inode does the
	 * right job
	 *
	 * We don't need to take the i_lock because
	 * the inode is not visible to user space.
	 */
	tmp_inode->i_blocks = 0;

	/* Reset the extent details */
	ext4_ext_tree_init(handle, tmp_inode);

	/*
	 * Set the i_nlink to zero so that
	 * generic_drop_inode really deletes the
	 * inode
	 */
	tmp_inode->i_nlink = 0;

	ext4_journal_stop(handle);
	mutex_unlock(&(inode->i_mutex));

	if (tmp_inode)
		iput(tmp_inode);

	return retval;
}