Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ext4 / migrate.c
blob46fc0b5b12bab540cf00bb1ffb7fcec1b51854fa
1 /*
2 * Copyright IBM Corporation, 2007
3 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of version 2.1 of the GNU Lesser General Public License
7 * as published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
15 #include <linux/module.h>
16 #include "ext4_jbd2.h"
17 #include "ext4_extents.h"
20 * The contiguous blocks details which can be
21 * represented by a single extent
23 struct list_blocks_struct {
24 ext4_lblk_t first_block, last_block;
25 ext4_fsblk_t first_pblock, last_pblock;
28 static int finish_range(handle_t *handle, struct inode *inode,
29 struct list_blocks_struct *lb)
32 int retval = 0, needed;
33 struct ext4_extent newext;
34 struct ext4_ext_path *path;
35 if (lb->first_pblock == 0)
36 return 0;
38 /* Add the extent to temp inode*/
39 newext.ee_block = cpu_to_le32(lb->first_block);
40 newext.ee_len = cpu_to_le16(lb->last_block - lb->first_block + 1);
41 ext4_ext_store_pblock(&newext, lb->first_pblock);
42 path = ext4_ext_find_extent(inode, lb->first_block, NULL);
44 if (IS_ERR(path)) {
45 retval = PTR_ERR(path);
46 path = NULL;
47 goto err_out;
51 * Calculate the credit needed to inserting this extent
52 * Since we are doing this in loop we may accumalate extra
53 * credit. But below we try to not accumalate too much
54 * of them by restarting the journal.
56 needed = ext4_ext_calc_credits_for_single_extent(inode,
57 lb->last_block - lb->first_block + 1, path);
60 * Make sure the credit we accumalated is not really high
62 if (needed && handle->h_buffer_credits >= EXT4_RESERVE_TRANS_BLOCKS) {
63 retval = ext4_journal_restart(handle, needed);
64 if (retval)
65 goto err_out;
66 } else if (needed) {
67 retval = ext4_journal_extend(handle, needed);
68 if (retval) {
70 * IF not able to extend the journal restart the journal
72 retval = ext4_journal_restart(handle, needed);
73 if (retval)
74 goto err_out;
77 retval = ext4_ext_insert_extent(handle, inode, path, &newext);
78 err_out:
79 if (path) {
80 ext4_ext_drop_refs(path);
81 kfree(path);
83 lb->first_pblock = 0;
84 return retval;
87 static int update_extent_range(handle_t *handle, struct inode *inode,
88 ext4_fsblk_t pblock, ext4_lblk_t blk_num,
89 struct list_blocks_struct *lb)
91 int retval;
93 * See if we can add on to the existing range (if it exists)
95 if (lb->first_pblock &&
96 (lb->last_pblock+1 == pblock) &&
97 (lb->last_block+1 == blk_num)) {
98 lb->last_pblock = pblock;
99 lb->last_block = blk_num;
100 return 0;
103 * Start a new range.
105 retval = finish_range(handle, inode, lb);
106 lb->first_pblock = lb->last_pblock = pblock;
107 lb->first_block = lb->last_block = blk_num;
109 return retval;
112 static int update_ind_extent_range(handle_t *handle, struct inode *inode,
113 ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
114 struct list_blocks_struct *lb)
116 struct buffer_head *bh;
117 __le32 *i_data;
118 int i, retval = 0;
119 ext4_lblk_t blk_count = *blk_nump;
120 unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
122 if (!pblock) {
123 /* Only update the file block number */
124 *blk_nump += max_entries;
125 return 0;
128 bh = sb_bread(inode->i_sb, pblock);
129 if (!bh)
130 return -EIO;
132 i_data = (__le32 *)bh->b_data;
133 for (i = 0; i < max_entries; i++, blk_count++) {
134 if (i_data[i]) {
135 retval = update_extent_range(handle, inode,
136 le32_to_cpu(i_data[i]),
137 blk_count, lb);
138 if (retval)
139 break;
143 /* Update the file block number */
144 *blk_nump = blk_count;
145 put_bh(bh);
146 return retval;
150 static int update_dind_extent_range(handle_t *handle, struct inode *inode,
151 ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
152 struct list_blocks_struct *lb)
154 struct buffer_head *bh;
155 __le32 *i_data;
156 int i, retval = 0;
157 ext4_lblk_t blk_count = *blk_nump;
158 unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
160 if (!pblock) {
161 /* Only update the file block number */
162 *blk_nump += max_entries * max_entries;
163 return 0;
165 bh = sb_bread(inode->i_sb, pblock);
166 if (!bh)
167 return -EIO;
169 i_data = (__le32 *)bh->b_data;
170 for (i = 0; i < max_entries; i++) {
171 if (i_data[i]) {
172 retval = update_ind_extent_range(handle, inode,
173 le32_to_cpu(i_data[i]),
174 &blk_count, lb);
175 if (retval)
176 break;
177 } else {
178 /* Only update the file block number */
179 blk_count += max_entries;
183 /* Update the file block number */
184 *blk_nump = blk_count;
185 put_bh(bh);
186 return retval;
190 static int update_tind_extent_range(handle_t *handle, struct inode *inode,
191 ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
192 struct list_blocks_struct *lb)
194 struct buffer_head *bh;
195 __le32 *i_data;
196 int i, retval = 0;
197 ext4_lblk_t blk_count = *blk_nump;
198 unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
200 if (!pblock) {
201 /* Only update the file block number */
202 *blk_nump += max_entries * max_entries * max_entries;
203 return 0;
205 bh = sb_bread(inode->i_sb, pblock);
206 if (!bh)
207 return -EIO;
209 i_data = (__le32 *)bh->b_data;
210 for (i = 0; i < max_entries; i++) {
211 if (i_data[i]) {
212 retval = update_dind_extent_range(handle, inode,
213 le32_to_cpu(i_data[i]),
214 &blk_count, lb);
215 if (retval)
216 break;
217 } else
218 /* Only update the file block number */
219 blk_count += max_entries * max_entries;
221 /* Update the file block number */
222 *blk_nump = blk_count;
223 put_bh(bh);
224 return retval;
228 static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode)
230 int retval = 0, needed;
232 if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
233 return 0;
235 * We are freeing a blocks. During this we touch
236 * superblock, group descriptor and block bitmap.
237 * So allocate a credit of 3. We may update
238 * quota (user and group).
240 needed = 3 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
242 if (ext4_journal_extend(handle, needed) != 0)
243 retval = ext4_journal_restart(handle, needed);
245 return retval;
248 static int free_dind_blocks(handle_t *handle,
249 struct inode *inode, __le32 i_data)
251 int i;
252 __le32 *tmp_idata;
253 struct buffer_head *bh;
254 unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
256 bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
257 if (!bh)
258 return -EIO;
260 tmp_idata = (__le32 *)bh->b_data;
261 for (i = 0; i < max_entries; i++) {
262 if (tmp_idata[i]) {
263 extend_credit_for_blkdel(handle, inode);
264 ext4_free_blocks(handle, inode,
265 le32_to_cpu(tmp_idata[i]), 1, 1);
268 put_bh(bh);
269 extend_credit_for_blkdel(handle, inode);
270 ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
271 return 0;
274 static int free_tind_blocks(handle_t *handle,
275 struct inode *inode, __le32 i_data)
277 int i, retval = 0;
278 __le32 *tmp_idata;
279 struct buffer_head *bh;
280 unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
282 bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
283 if (!bh)
284 return -EIO;
286 tmp_idata = (__le32 *)bh->b_data;
287 for (i = 0; i < max_entries; i++) {
288 if (tmp_idata[i]) {
289 retval = free_dind_blocks(handle,
290 inode, tmp_idata[i]);
291 if (retval) {
292 put_bh(bh);
293 return retval;
297 put_bh(bh);
298 extend_credit_for_blkdel(handle, inode);
299 ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
300 return 0;
303 static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
305 int retval;
307 /* ei->i_data[EXT4_IND_BLOCK] */
308 if (i_data[0]) {
309 extend_credit_for_blkdel(handle, inode);
310 ext4_free_blocks(handle, inode,
311 le32_to_cpu(i_data[0]), 1, 1);
314 /* ei->i_data[EXT4_DIND_BLOCK] */
315 if (i_data[1]) {
316 retval = free_dind_blocks(handle, inode, i_data[1]);
317 if (retval)
318 return retval;
321 /* ei->i_data[EXT4_TIND_BLOCK] */
322 if (i_data[2]) {
323 retval = free_tind_blocks(handle, inode, i_data[2]);
324 if (retval)
325 return retval;
327 return 0;
330 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
331 struct inode *tmp_inode)
333 int retval;
334 __le32 i_data[3];
335 struct ext4_inode_info *ei = EXT4_I(inode);
336 struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
339 * One credit accounted for writing the
340 * i_data field of the original inode
342 retval = ext4_journal_extend(handle, 1);
343 if (retval) {
344 retval = ext4_journal_restart(handle, 1);
345 if (retval)
346 goto err_out;
349 i_data[0] = ei->i_data[EXT4_IND_BLOCK];
350 i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
351 i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
353 down_write(&EXT4_I(inode)->i_data_sem);
355 * if EXT4_EXT_MIGRATE is cleared a block allocation
356 * happened after we started the migrate. We need to
357 * fail the migrate
359 if (!(EXT4_I(inode)->i_flags & EXT4_EXT_MIGRATE)) {
360 retval = -EAGAIN;
361 up_write(&EXT4_I(inode)->i_data_sem);
362 goto err_out;
363 } else
364 EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
365 ~EXT4_EXT_MIGRATE;
367 * We have the extent map build with the tmp inode.
368 * Now copy the i_data across
370 ei->i_flags |= EXT4_EXTENTS_FL;
371 memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
374 * Update i_blocks with the new blocks that got
375 * allocated while adding extents for extent index
376 * blocks.
378 * While converting to extents we need not
379 * update the orignal inode i_blocks for extent blocks
380 * via quota APIs. The quota update happened via tmp_inode already.
382 spin_lock(&inode->i_lock);
383 inode->i_blocks += tmp_inode->i_blocks;
384 spin_unlock(&inode->i_lock);
385 up_write(&EXT4_I(inode)->i_data_sem);
388 * We mark the inode dirty after, because we decrement the
389 * i_blocks when freeing the indirect meta-data blocks
391 retval = free_ind_block(handle, inode, i_data);
392 ext4_mark_inode_dirty(handle, inode);
394 err_out:
395 return retval;
398 static int free_ext_idx(handle_t *handle, struct inode *inode,
399 struct ext4_extent_idx *ix)
401 int i, retval = 0;
402 ext4_fsblk_t block;
403 struct buffer_head *bh;
404 struct ext4_extent_header *eh;
406 block = idx_pblock(ix);
407 bh = sb_bread(inode->i_sb, block);
408 if (!bh)
409 return -EIO;
411 eh = (struct ext4_extent_header *)bh->b_data;
412 if (eh->eh_depth != 0) {
413 ix = EXT_FIRST_INDEX(eh);
414 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
415 retval = free_ext_idx(handle, inode, ix);
416 if (retval)
417 break;
420 put_bh(bh);
421 extend_credit_for_blkdel(handle, inode);
422 ext4_free_blocks(handle, inode, block, 1, 1);
423 return retval;
427 * Free the extent meta data blocks only
429 static int free_ext_block(handle_t *handle, struct inode *inode)
431 int i, retval = 0;
432 struct ext4_inode_info *ei = EXT4_I(inode);
433 struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
434 struct ext4_extent_idx *ix;
435 if (eh->eh_depth == 0)
437 * No extra blocks allocated for extent meta data
439 return 0;
440 ix = EXT_FIRST_INDEX(eh);
441 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
442 retval = free_ext_idx(handle, inode, ix);
443 if (retval)
444 return retval;
446 return retval;
450 int ext4_ext_migrate(struct inode *inode, struct file *filp,
451 unsigned int cmd, unsigned long arg)
453 handle_t *handle;
454 int retval = 0, i;
455 __le32 *i_data;
456 ext4_lblk_t blk_count = 0;
457 struct ext4_inode_info *ei;
458 struct inode *tmp_inode = NULL;
459 struct list_blocks_struct lb;
460 unsigned long max_entries;
462 if (!test_opt(inode->i_sb, EXTENTS))
464 * if mounted with noextents we don't allow the migrate
466 return -EINVAL;
468 if ((EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
469 return -EINVAL;
471 if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
473 * don't migrate fast symlink
475 return retval;
477 handle = ext4_journal_start(inode,
478 EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
479 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
480 2 * EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)
481 + 1);
482 if (IS_ERR(handle)) {
483 retval = PTR_ERR(handle);
484 goto err_out;
486 tmp_inode = ext4_new_inode(handle,
487 inode->i_sb->s_root->d_inode,
488 S_IFREG);
489 if (IS_ERR(tmp_inode)) {
490 retval = -ENOMEM;
491 ext4_journal_stop(handle);
492 tmp_inode = NULL;
493 goto err_out;
495 i_size_write(tmp_inode, i_size_read(inode));
497 * We don't want the inode to be reclaimed
498 * if we got interrupted in between. We have
499 * this tmp inode carrying reference to the
500 * data blocks of the original file. We set
501 * the i_nlink to zero at the last stage after
502 * switching the original file to extent format
504 tmp_inode->i_nlink = 1;
506 ext4_ext_tree_init(handle, tmp_inode);
507 ext4_orphan_add(handle, tmp_inode);
508 ext4_journal_stop(handle);
511 * start with one credit accounted for
512 * superblock modification.
514 * For the tmp_inode we already have commited the
515 * trascation that created the inode. Later as and
516 * when we add extents we extent the journal
519 * inode_mutex prevent write and truncate on the file. Read still goes
520 * through. We take i_data_sem in ext4_ext_swap_inode_data before we
521 * switch the inode format to prevent read.
523 mutex_lock(&(inode->i_mutex));
525 * Even though we take i_mutex we can still cause block allocation
526 * via mmap write to holes. If we have allocated new blocks we fail
527 * migrate. New block allocation will clear EXT4_EXT_MIGRATE flag.
528 * The flag is updated with i_data_sem held to prevent racing with
529 * block allocation.
531 down_read((&EXT4_I(inode)->i_data_sem));
532 EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags | EXT4_EXT_MIGRATE;
533 up_read((&EXT4_I(inode)->i_data_sem));
535 handle = ext4_journal_start(inode, 1);
537 ei = EXT4_I(inode);
538 i_data = ei->i_data;
539 memset(&lb, 0, sizeof(lb));
541 /* 32 bit block address 4 bytes */
542 max_entries = inode->i_sb->s_blocksize >> 2;
543 for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) {
544 if (i_data[i]) {
545 retval = update_extent_range(handle, tmp_inode,
546 le32_to_cpu(i_data[i]),
547 blk_count, &lb);
548 if (retval)
549 goto err_out;
552 if (i_data[EXT4_IND_BLOCK]) {
553 retval = update_ind_extent_range(handle, tmp_inode,
554 le32_to_cpu(i_data[EXT4_IND_BLOCK]),
555 &blk_count, &lb);
556 if (retval)
557 goto err_out;
558 } else
559 blk_count += max_entries;
560 if (i_data[EXT4_DIND_BLOCK]) {
561 retval = update_dind_extent_range(handle, tmp_inode,
562 le32_to_cpu(i_data[EXT4_DIND_BLOCK]),
563 &blk_count, &lb);
564 if (retval)
565 goto err_out;
566 } else
567 blk_count += max_entries * max_entries;
568 if (i_data[EXT4_TIND_BLOCK]) {
569 retval = update_tind_extent_range(handle, tmp_inode,
570 le32_to_cpu(i_data[EXT4_TIND_BLOCK]),
571 &blk_count, &lb);
572 if (retval)
573 goto err_out;
576 * Build the last extent
578 retval = finish_range(handle, tmp_inode, &lb);
579 err_out:
580 if (retval)
582 * Failure case delete the extent information with the
583 * tmp_inode
585 free_ext_block(handle, tmp_inode);
586 else {
587 retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
588 if (retval)
590 * if we fail to swap inode data free the extent
591 * details of the tmp inode
593 free_ext_block(handle, tmp_inode);
596 /* We mark the tmp_inode dirty via ext4_ext_tree_init. */
597 if (ext4_journal_extend(handle, 1) != 0)
598 ext4_journal_restart(handle, 1);
601 * Mark the tmp_inode as of size zero
603 i_size_write(tmp_inode, 0);
606 * set the i_blocks count to zero
607 * so that the ext4_delete_inode does the
608 * right job
610 * We don't need to take the i_lock because
611 * the inode is not visible to user space.
613 tmp_inode->i_blocks = 0;
615 /* Reset the extent details */
616 ext4_ext_tree_init(handle, tmp_inode);
619 * Set the i_nlink to zero so that
620 * generic_drop_inode really deletes the
621 * inode
623 tmp_inode->i_nlink = 0;
625 ext4_journal_stop(handle);
626 mutex_unlock(&(inode->i_mutex));
628 if (tmp_inode)
629 iput(tmp_inode);
631 return retval;