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[/] [test_project/] [trunk/] [linux_sd_driver/] [fs/] [ext4/] [resize.c] - Blame information for rev 62

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Line No. Rev Author Line
1 62 marcus.erl
/*
2
 *  linux/fs/ext4/resize.c
3
 *
4
 * Support for resizing an ext4 filesystem while it is mounted.
5
 *
6
 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
7
 *
8
 * This could probably be made into a module, because it is not often in use.
9
 */
10
 
11
 
12
#define EXT4FS_DEBUG
13
 
14
#include <linux/ext4_jbd2.h>
15
 
16
#include <linux/errno.h>
17
#include <linux/slab.h>
18
 
19
#include "group.h"
20
 
21
#define outside(b, first, last) ((b) < (first) || (b) >= (last))
22
#define inside(b, first, last)  ((b) >= (first) && (b) < (last))
23
 
24
static int verify_group_input(struct super_block *sb,
25
                              struct ext4_new_group_data *input)
26
{
27
        struct ext4_sb_info *sbi = EXT4_SB(sb);
28
        struct ext4_super_block *es = sbi->s_es;
29
        ext4_fsblk_t start = ext4_blocks_count(es);
30
        ext4_fsblk_t end = start + input->blocks_count;
31
        unsigned group = input->group;
32
        ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
33
        unsigned overhead = ext4_bg_has_super(sb, group) ?
34
                (1 + ext4_bg_num_gdb(sb, group) +
35
                 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
36
        ext4_fsblk_t metaend = start + overhead;
37
        struct buffer_head *bh = NULL;
38
        ext4_grpblk_t free_blocks_count, offset;
39
        int err = -EINVAL;
40
 
41
        input->free_blocks_count = free_blocks_count =
42
                input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
43
 
44
        if (test_opt(sb, DEBUG))
45
                printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
46
                       "(%d free, %u reserved)\n",
47
                       ext4_bg_has_super(sb, input->group) ? "normal" :
48
                       "no-super", input->group, input->blocks_count,
49
                       free_blocks_count, input->reserved_blocks);
50
 
51
        ext4_get_group_no_and_offset(sb, start, NULL, &offset);
52
        if (group != sbi->s_groups_count)
53
                ext4_warning(sb, __FUNCTION__,
54
                             "Cannot add at group %u (only %lu groups)",
55
                             input->group, sbi->s_groups_count);
56
        else if (offset != 0)
57
                        ext4_warning(sb, __FUNCTION__, "Last group not full");
58
        else if (input->reserved_blocks > input->blocks_count / 5)
59
                ext4_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
60
                             input->reserved_blocks);
61
        else if (free_blocks_count < 0)
62
                ext4_warning(sb, __FUNCTION__, "Bad blocks count %u",
63
                             input->blocks_count);
64
        else if (!(bh = sb_bread(sb, end - 1)))
65
                ext4_warning(sb, __FUNCTION__,
66
                             "Cannot read last block (%llu)",
67
                             end - 1);
68
        else if (outside(input->block_bitmap, start, end))
69
                ext4_warning(sb, __FUNCTION__,
70
                             "Block bitmap not in group (block %llu)",
71
                             (unsigned long long)input->block_bitmap);
72
        else if (outside(input->inode_bitmap, start, end))
73
                ext4_warning(sb, __FUNCTION__,
74
                             "Inode bitmap not in group (block %llu)",
75
                             (unsigned long long)input->inode_bitmap);
76
        else if (outside(input->inode_table, start, end) ||
77
                 outside(itend - 1, start, end))
78
                ext4_warning(sb, __FUNCTION__,
79
                             "Inode table not in group (blocks %llu-%llu)",
80
                             (unsigned long long)input->inode_table, itend - 1);
81
        else if (input->inode_bitmap == input->block_bitmap)
82
                ext4_warning(sb, __FUNCTION__,
83
                             "Block bitmap same as inode bitmap (%llu)",
84
                             (unsigned long long)input->block_bitmap);
85
        else if (inside(input->block_bitmap, input->inode_table, itend))
86
                ext4_warning(sb, __FUNCTION__,
87
                             "Block bitmap (%llu) in inode table (%llu-%llu)",
88
                             (unsigned long long)input->block_bitmap,
89
                             (unsigned long long)input->inode_table, itend - 1);
90
        else if (inside(input->inode_bitmap, input->inode_table, itend))
91
                ext4_warning(sb, __FUNCTION__,
92
                             "Inode bitmap (%llu) in inode table (%llu-%llu)",
93
                             (unsigned long long)input->inode_bitmap,
94
                             (unsigned long long)input->inode_table, itend - 1);
95
        else if (inside(input->block_bitmap, start, metaend))
96
                ext4_warning(sb, __FUNCTION__,
97
                             "Block bitmap (%llu) in GDT table"
98
                             " (%llu-%llu)",
99
                             (unsigned long long)input->block_bitmap,
100
                             start, metaend - 1);
101
        else if (inside(input->inode_bitmap, start, metaend))
102
                ext4_warning(sb, __FUNCTION__,
103
                             "Inode bitmap (%llu) in GDT table"
104
                             " (%llu-%llu)",
105
                             (unsigned long long)input->inode_bitmap,
106
                             start, metaend - 1);
107
        else if (inside(input->inode_table, start, metaend) ||
108
                 inside(itend - 1, start, metaend))
109
                ext4_warning(sb, __FUNCTION__,
110
                             "Inode table (%llu-%llu) overlaps"
111
                             "GDT table (%llu-%llu)",
112
                             (unsigned long long)input->inode_table,
113
                             itend - 1, start, metaend - 1);
114
        else
115
                err = 0;
116
        brelse(bh);
117
 
118
        return err;
119
}
120
 
121
static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
122
                                  ext4_fsblk_t blk)
123
{
124
        struct buffer_head *bh;
125
        int err;
126
 
127
        bh = sb_getblk(sb, blk);
128
        if (!bh)
129
                return ERR_PTR(-EIO);
130
        if ((err = ext4_journal_get_write_access(handle, bh))) {
131
                brelse(bh);
132
                bh = ERR_PTR(err);
133
        } else {
134
                lock_buffer(bh);
135
                memset(bh->b_data, 0, sb->s_blocksize);
136
                set_buffer_uptodate(bh);
137
                unlock_buffer(bh);
138
        }
139
 
140
        return bh;
141
}
142
 
143
/*
144
 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
145
 * If that fails, restart the transaction & regain write access for the
146
 * buffer head which is used for block_bitmap modifications.
147
 */
148
static int extend_or_restart_transaction(handle_t *handle, int thresh,
149
                                         struct buffer_head *bh)
150
{
151
        int err;
152
 
153
        if (handle->h_buffer_credits >= thresh)
154
                return 0;
155
 
156
        err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
157
        if (err < 0)
158
                return err;
159
        if (err) {
160
                if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
161
                        return err;
162
                if ((err = ext4_journal_get_write_access(handle, bh)))
163
                        return err;
164
        }
165
 
166
        return 0;
167
}
168
 
169
/*
170
 * Set up the block and inode bitmaps, and the inode table for the new group.
171
 * This doesn't need to be part of the main transaction, since we are only
172
 * changing blocks outside the actual filesystem.  We still do journaling to
173
 * ensure the recovery is correct in case of a failure just after resize.
174
 * If any part of this fails, we simply abort the resize.
175
 */
176
static int setup_new_group_blocks(struct super_block *sb,
177
                                  struct ext4_new_group_data *input)
178
{
179
        struct ext4_sb_info *sbi = EXT4_SB(sb);
180
        ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group);
181
        int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
182
                le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
183
        unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group);
184
        struct buffer_head *bh;
185
        handle_t *handle;
186
        ext4_fsblk_t block;
187
        ext4_grpblk_t bit;
188
        int i;
189
        int err = 0, err2;
190
 
191
        /* This transaction may be extended/restarted along the way */
192
        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
193
 
194
        if (IS_ERR(handle))
195
                return PTR_ERR(handle);
196
 
197
        lock_super(sb);
198
        if (input->group != sbi->s_groups_count) {
199
                err = -EBUSY;
200
                goto exit_journal;
201
        }
202
 
203
        if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
204
                err = PTR_ERR(bh);
205
                goto exit_journal;
206
        }
207
 
208
        if (ext4_bg_has_super(sb, input->group)) {
209
                ext4_debug("mark backup superblock %#04lx (+0)\n", start);
210
                ext4_set_bit(0, bh->b_data);
211
        }
212
 
213
        /* Copy all of the GDT blocks into the backup in this group */
214
        for (i = 0, bit = 1, block = start + 1;
215
             i < gdblocks; i++, block++, bit++) {
216
                struct buffer_head *gdb;
217
 
218
                ext4_debug("update backup group %#04lx (+%d)\n", block, bit);
219
 
220
                if ((err = extend_or_restart_transaction(handle, 1, bh)))
221
                        goto exit_bh;
222
 
223
                gdb = sb_getblk(sb, block);
224
                if (!gdb) {
225
                        err = -EIO;
226
                        goto exit_bh;
227
                }
228
                if ((err = ext4_journal_get_write_access(handle, gdb))) {
229
                        brelse(gdb);
230
                        goto exit_bh;
231
                }
232
                lock_buffer(gdb);
233
                memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
234
                set_buffer_uptodate(gdb);
235
                unlock_buffer(gdb);
236
                ext4_journal_dirty_metadata(handle, gdb);
237
                ext4_set_bit(bit, bh->b_data);
238
                brelse(gdb);
239
        }
240
 
241
        /* Zero out all of the reserved backup group descriptor table blocks */
242
        for (i = 0, bit = gdblocks + 1, block = start + bit;
243
             i < reserved_gdb; i++, block++, bit++) {
244
                struct buffer_head *gdb;
245
 
246
                ext4_debug("clear reserved block %#04lx (+%d)\n", block, bit);
247
 
248
                if ((err = extend_or_restart_transaction(handle, 1, bh)))
249
                        goto exit_bh;
250
 
251
                if (IS_ERR(gdb = bclean(handle, sb, block))) {
252
                        err = PTR_ERR(bh);
253
                        goto exit_bh;
254
                }
255
                ext4_journal_dirty_metadata(handle, gdb);
256
                ext4_set_bit(bit, bh->b_data);
257
                brelse(gdb);
258
        }
259
        ext4_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
260
                   input->block_bitmap - start);
261
        ext4_set_bit(input->block_bitmap - start, bh->b_data);
262
        ext4_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
263
                   input->inode_bitmap - start);
264
        ext4_set_bit(input->inode_bitmap - start, bh->b_data);
265
 
266
        /* Zero out all of the inode table blocks */
267
        for (i = 0, block = input->inode_table, bit = block - start;
268
             i < sbi->s_itb_per_group; i++, bit++, block++) {
269
                struct buffer_head *it;
270
 
271
                ext4_debug("clear inode block %#04lx (+%d)\n", block, bit);
272
 
273
                if ((err = extend_or_restart_transaction(handle, 1, bh)))
274
                        goto exit_bh;
275
 
276
                if (IS_ERR(it = bclean(handle, sb, block))) {
277
                        err = PTR_ERR(it);
278
                        goto exit_bh;
279
                }
280
                ext4_journal_dirty_metadata(handle, it);
281
                brelse(it);
282
                ext4_set_bit(bit, bh->b_data);
283
        }
284
 
285
        if ((err = extend_or_restart_transaction(handle, 2, bh)))
286
                goto exit_bh;
287
 
288
        mark_bitmap_end(input->blocks_count, EXT4_BLOCKS_PER_GROUP(sb),
289
                        bh->b_data);
290
        ext4_journal_dirty_metadata(handle, bh);
291
        brelse(bh);
292
 
293
        /* Mark unused entries in inode bitmap used */
294
        ext4_debug("clear inode bitmap %#04x (+%ld)\n",
295
                   input->inode_bitmap, input->inode_bitmap - start);
296
        if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
297
                err = PTR_ERR(bh);
298
                goto exit_journal;
299
        }
300
 
301
        mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb),
302
                        bh->b_data);
303
        ext4_journal_dirty_metadata(handle, bh);
304
exit_bh:
305
        brelse(bh);
306
 
307
exit_journal:
308
        unlock_super(sb);
309
        if ((err2 = ext4_journal_stop(handle)) && !err)
310
                err = err2;
311
 
312
        return err;
313
}
314
 
315
/*
316
 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
317
 * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
318
 * calling this for the first time.  In a sparse filesystem it will be the
319
 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
320
 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
321
 */
322
static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
323
                                  unsigned *five, unsigned *seven)
324
{
325
        unsigned *min = three;
326
        int mult = 3;
327
        unsigned ret;
328
 
329
        if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
330
                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
331
                ret = *min;
332
                *min += 1;
333
                return ret;
334
        }
335
 
336
        if (*five < *min) {
337
                min = five;
338
                mult = 5;
339
        }
340
        if (*seven < *min) {
341
                min = seven;
342
                mult = 7;
343
        }
344
 
345
        ret = *min;
346
        *min *= mult;
347
 
348
        return ret;
349
}
350
 
351
/*
352
 * Check that all of the backup GDT blocks are held in the primary GDT block.
353
 * It is assumed that they are stored in group order.  Returns the number of
354
 * groups in current filesystem that have BACKUPS, or -ve error code.
355
 */
356
static int verify_reserved_gdb(struct super_block *sb,
357
                               struct buffer_head *primary)
358
{
359
        const ext4_fsblk_t blk = primary->b_blocknr;
360
        const unsigned long end = EXT4_SB(sb)->s_groups_count;
361
        unsigned three = 1;
362
        unsigned five = 5;
363
        unsigned seven = 7;
364
        unsigned grp;
365
        __le32 *p = (__le32 *)primary->b_data;
366
        int gdbackups = 0;
367
 
368
        while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
369
                if (le32_to_cpu(*p++) !=
370
                    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
371
                        ext4_warning(sb, __FUNCTION__,
372
                                     "reserved GDT %llu"
373
                                     " missing grp %d (%llu)",
374
                                     blk, grp,
375
                                     grp *
376
                                     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
377
                                     blk);
378
                        return -EINVAL;
379
                }
380
                if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
381
                        return -EFBIG;
382
        }
383
 
384
        return gdbackups;
385
}
386
 
387
/*
388
 * Called when we need to bring a reserved group descriptor table block into
389
 * use from the resize inode.  The primary copy of the new GDT block currently
390
 * is an indirect block (under the double indirect block in the resize inode).
391
 * The new backup GDT blocks will be stored as leaf blocks in this indirect
392
 * block, in group order.  Even though we know all the block numbers we need,
393
 * we check to ensure that the resize inode has actually reserved these blocks.
394
 *
395
 * Don't need to update the block bitmaps because the blocks are still in use.
396
 *
397
 * We get all of the error cases out of the way, so that we are sure to not
398
 * fail once we start modifying the data on disk, because JBD has no rollback.
399
 */
400
static int add_new_gdb(handle_t *handle, struct inode *inode,
401
                       struct ext4_new_group_data *input,
402
                       struct buffer_head **primary)
403
{
404
        struct super_block *sb = inode->i_sb;
405
        struct ext4_super_block *es = EXT4_SB(sb)->s_es;
406
        unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
407
        ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
408
        struct buffer_head **o_group_desc, **n_group_desc;
409
        struct buffer_head *dind;
410
        int gdbackups;
411
        struct ext4_iloc iloc;
412
        __le32 *data;
413
        int err;
414
 
415
        if (test_opt(sb, DEBUG))
416
                printk(KERN_DEBUG
417
                       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
418
                       gdb_num);
419
 
420
        /*
421
         * If we are not using the primary superblock/GDT copy don't resize,
422
         * because the user tools have no way of handling this.  Probably a
423
         * bad time to do it anyways.
424
         */
425
        if (EXT4_SB(sb)->s_sbh->b_blocknr !=
426
            le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
427
                ext4_warning(sb, __FUNCTION__,
428
                        "won't resize using backup superblock at %llu",
429
                        (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
430
                return -EPERM;
431
        }
432
 
433
        *primary = sb_bread(sb, gdblock);
434
        if (!*primary)
435
                return -EIO;
436
 
437
        if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
438
                err = gdbackups;
439
                goto exit_bh;
440
        }
441
 
442
        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
443
        dind = sb_bread(sb, le32_to_cpu(*data));
444
        if (!dind) {
445
                err = -EIO;
446
                goto exit_bh;
447
        }
448
 
449
        data = (__le32 *)dind->b_data;
450
        if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
451
                ext4_warning(sb, __FUNCTION__,
452
                             "new group %u GDT block %llu not reserved",
453
                             input->group, gdblock);
454
                err = -EINVAL;
455
                goto exit_dind;
456
        }
457
 
458
        if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh)))
459
                goto exit_dind;
460
 
461
        if ((err = ext4_journal_get_write_access(handle, *primary)))
462
                goto exit_sbh;
463
 
464
        if ((err = ext4_journal_get_write_access(handle, dind)))
465
                goto exit_primary;
466
 
467
        /* ext4_reserve_inode_write() gets a reference on the iloc */
468
        if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
469
                goto exit_dindj;
470
 
471
        n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
472
                        GFP_KERNEL);
473
        if (!n_group_desc) {
474
                err = -ENOMEM;
475
                ext4_warning (sb, __FUNCTION__,
476
                              "not enough memory for %lu groups", gdb_num + 1);
477
                goto exit_inode;
478
        }
479
 
480
        /*
481
         * Finally, we have all of the possible failures behind us...
482
         *
483
         * Remove new GDT block from inode double-indirect block and clear out
484
         * the new GDT block for use (which also "frees" the backup GDT blocks
485
         * from the reserved inode).  We don't need to change the bitmaps for
486
         * these blocks, because they are marked as in-use from being in the
487
         * reserved inode, and will become GDT blocks (primary and backup).
488
         */
489
        data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
490
        ext4_journal_dirty_metadata(handle, dind);
491
        brelse(dind);
492
        inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
493
        ext4_mark_iloc_dirty(handle, inode, &iloc);
494
        memset((*primary)->b_data, 0, sb->s_blocksize);
495
        ext4_journal_dirty_metadata(handle, *primary);
496
 
497
        o_group_desc = EXT4_SB(sb)->s_group_desc;
498
        memcpy(n_group_desc, o_group_desc,
499
               EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
500
        n_group_desc[gdb_num] = *primary;
501
        EXT4_SB(sb)->s_group_desc = n_group_desc;
502
        EXT4_SB(sb)->s_gdb_count++;
503
        kfree(o_group_desc);
504
 
505
        es->s_reserved_gdt_blocks =
506
                cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
507
        ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
508
 
509
        return 0;
510
 
511
exit_inode:
512
        //ext4_journal_release_buffer(handle, iloc.bh);
513
        brelse(iloc.bh);
514
exit_dindj:
515
        //ext4_journal_release_buffer(handle, dind);
516
exit_primary:
517
        //ext4_journal_release_buffer(handle, *primary);
518
exit_sbh:
519
        //ext4_journal_release_buffer(handle, *primary);
520
exit_dind:
521
        brelse(dind);
522
exit_bh:
523
        brelse(*primary);
524
 
525
        ext4_debug("leaving with error %d\n", err);
526
        return err;
527
}
528
 
529
/*
530
 * Called when we are adding a new group which has a backup copy of each of
531
 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
532
 * We need to add these reserved backup GDT blocks to the resize inode, so
533
 * that they are kept for future resizing and not allocated to files.
534
 *
535
 * Each reserved backup GDT block will go into a different indirect block.
536
 * The indirect blocks are actually the primary reserved GDT blocks,
537
 * so we know in advance what their block numbers are.  We only get the
538
 * double-indirect block to verify it is pointing to the primary reserved
539
 * GDT blocks so we don't overwrite a data block by accident.  The reserved
540
 * backup GDT blocks are stored in their reserved primary GDT block.
541
 */
542
static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
543
                              struct ext4_new_group_data *input)
544
{
545
        struct super_block *sb = inode->i_sb;
546
        int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
547
        struct buffer_head **primary;
548
        struct buffer_head *dind;
549
        struct ext4_iloc iloc;
550
        ext4_fsblk_t blk;
551
        __le32 *data, *end;
552
        int gdbackups = 0;
553
        int res, i;
554
        int err;
555
 
556
        primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
557
        if (!primary)
558
                return -ENOMEM;
559
 
560
        data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
561
        dind = sb_bread(sb, le32_to_cpu(*data));
562
        if (!dind) {
563
                err = -EIO;
564
                goto exit_free;
565
        }
566
 
567
        blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
568
        data = (__le32 *)dind->b_data + EXT4_SB(sb)->s_gdb_count;
569
        end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
570
 
571
        /* Get each reserved primary GDT block and verify it holds backups */
572
        for (res = 0; res < reserved_gdb; res++, blk++) {
573
                if (le32_to_cpu(*data) != blk) {
574
                        ext4_warning(sb, __FUNCTION__,
575
                                     "reserved block %llu"
576
                                     " not at offset %ld",
577
                                     blk,
578
                                     (long)(data - (__le32 *)dind->b_data));
579
                        err = -EINVAL;
580
                        goto exit_bh;
581
                }
582
                primary[res] = sb_bread(sb, blk);
583
                if (!primary[res]) {
584
                        err = -EIO;
585
                        goto exit_bh;
586
                }
587
                if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
588
                        brelse(primary[res]);
589
                        err = gdbackups;
590
                        goto exit_bh;
591
                }
592
                if (++data >= end)
593
                        data = (__le32 *)dind->b_data;
594
        }
595
 
596
        for (i = 0; i < reserved_gdb; i++) {
597
                if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
598
                        /*
599
                        int j;
600
                        for (j = 0; j < i; j++)
601
                                ext4_journal_release_buffer(handle, primary[j]);
602
                         */
603
                        goto exit_bh;
604
                }
605
        }
606
 
607
        if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
608
                goto exit_bh;
609
 
610
        /*
611
         * Finally we can add each of the reserved backup GDT blocks from
612
         * the new group to its reserved primary GDT block.
613
         */
614
        blk = input->group * EXT4_BLOCKS_PER_GROUP(sb);
615
        for (i = 0; i < reserved_gdb; i++) {
616
                int err2;
617
                data = (__le32 *)primary[i]->b_data;
618
                /* printk("reserving backup %lu[%u] = %lu\n",
619
                       primary[i]->b_blocknr, gdbackups,
620
                       blk + primary[i]->b_blocknr); */
621
                data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
622
                err2 = ext4_journal_dirty_metadata(handle, primary[i]);
623
                if (!err)
624
                        err = err2;
625
        }
626
        inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
627
        ext4_mark_iloc_dirty(handle, inode, &iloc);
628
 
629
exit_bh:
630
        while (--res >= 0)
631
                brelse(primary[res]);
632
        brelse(dind);
633
 
634
exit_free:
635
        kfree(primary);
636
 
637
        return err;
638
}
639
 
640
/*
641
 * Update the backup copies of the ext4 metadata.  These don't need to be part
642
 * of the main resize transaction, because e2fsck will re-write them if there
643
 * is a problem (basically only OOM will cause a problem).  However, we
644
 * _should_ update the backups if possible, in case the primary gets trashed
645
 * for some reason and we need to run e2fsck from a backup superblock.  The
646
 * important part is that the new block and inode counts are in the backup
647
 * superblocks, and the location of the new group metadata in the GDT backups.
648
 *
649
 * We do not need lock_super() for this, because these blocks are not
650
 * otherwise touched by the filesystem code when it is mounted.  We don't
651
 * need to worry about last changing from sbi->s_groups_count, because the
652
 * worst that can happen is that we do not copy the full number of backups
653
 * at this time.  The resize which changed s_groups_count will backup again.
654
 */
655
static void update_backups(struct super_block *sb,
656
                           int blk_off, char *data, int size)
657
{
658
        struct ext4_sb_info *sbi = EXT4_SB(sb);
659
        const unsigned long last = sbi->s_groups_count;
660
        const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
661
        unsigned three = 1;
662
        unsigned five = 5;
663
        unsigned seven = 7;
664
        unsigned group;
665
        int rest = sb->s_blocksize - size;
666
        handle_t *handle;
667
        int err = 0, err2;
668
 
669
        handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
670
        if (IS_ERR(handle)) {
671
                group = 1;
672
                err = PTR_ERR(handle);
673
                goto exit_err;
674
        }
675
 
676
        while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
677
                struct buffer_head *bh;
678
 
679
                /* Out of journal space, and can't get more - abort - so sad */
680
                if (handle->h_buffer_credits == 0 &&
681
                    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
682
                    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
683
                        break;
684
 
685
                bh = sb_getblk(sb, group * bpg + blk_off);
686
                if (!bh) {
687
                        err = -EIO;
688
                        break;
689
                }
690
                ext4_debug("update metadata backup %#04lx\n",
691
                          (unsigned long)bh->b_blocknr);
692
                if ((err = ext4_journal_get_write_access(handle, bh)))
693
                        break;
694
                lock_buffer(bh);
695
                memcpy(bh->b_data, data, size);
696
                if (rest)
697
                        memset(bh->b_data + size, 0, rest);
698
                set_buffer_uptodate(bh);
699
                unlock_buffer(bh);
700
                ext4_journal_dirty_metadata(handle, bh);
701
                brelse(bh);
702
        }
703
        if ((err2 = ext4_journal_stop(handle)) && !err)
704
                err = err2;
705
 
706
        /*
707
         * Ugh! Need to have e2fsck write the backup copies.  It is too
708
         * late to revert the resize, we shouldn't fail just because of
709
         * the backup copies (they are only needed in case of corruption).
710
         *
711
         * However, if we got here we have a journal problem too, so we
712
         * can't really start a transaction to mark the superblock.
713
         * Chicken out and just set the flag on the hope it will be written
714
         * to disk, and if not - we will simply wait until next fsck.
715
         */
716
exit_err:
717
        if (err) {
718
                ext4_warning(sb, __FUNCTION__,
719
                             "can't update backup for group %d (err %d), "
720
                             "forcing fsck on next reboot", group, err);
721
                sbi->s_mount_state &= ~EXT4_VALID_FS;
722
                sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
723
                mark_buffer_dirty(sbi->s_sbh);
724
        }
725
}
726
 
727
/* Add group descriptor data to an existing or new group descriptor block.
728
 * Ensure we handle all possible error conditions _before_ we start modifying
729
 * the filesystem, because we cannot abort the transaction and not have it
730
 * write the data to disk.
731
 *
732
 * If we are on a GDT block boundary, we need to get the reserved GDT block.
733
 * Otherwise, we may need to add backup GDT blocks for a sparse group.
734
 *
735
 * We only need to hold the superblock lock while we are actually adding
736
 * in the new group's counts to the superblock.  Prior to that we have
737
 * not really "added" the group at all.  We re-check that we are still
738
 * adding in the last group in case things have changed since verifying.
739
 */
740
int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
741
{
742
        struct ext4_sb_info *sbi = EXT4_SB(sb);
743
        struct ext4_super_block *es = sbi->s_es;
744
        int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
745
                le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
746
        struct buffer_head *primary = NULL;
747
        struct ext4_group_desc *gdp;
748
        struct inode *inode = NULL;
749
        handle_t *handle;
750
        int gdb_off, gdb_num;
751
        int err, err2;
752
 
753
        gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
754
        gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
755
 
756
        if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
757
                                        EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
758
                ext4_warning(sb, __FUNCTION__,
759
                             "Can't resize non-sparse filesystem further");
760
                return -EPERM;
761
        }
762
 
763
        if (ext4_blocks_count(es) + input->blocks_count <
764
            ext4_blocks_count(es)) {
765
                ext4_warning(sb, __FUNCTION__, "blocks_count overflow\n");
766
                return -EINVAL;
767
        }
768
 
769
        if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
770
            le32_to_cpu(es->s_inodes_count)) {
771
                ext4_warning(sb, __FUNCTION__, "inodes_count overflow\n");
772
                return -EINVAL;
773
        }
774
 
775
        if (reserved_gdb || gdb_off == 0) {
776
                if (!EXT4_HAS_COMPAT_FEATURE(sb,
777
                                             EXT4_FEATURE_COMPAT_RESIZE_INODE)){
778
                        ext4_warning(sb, __FUNCTION__,
779
                                     "No reserved GDT blocks, can't resize");
780
                        return -EPERM;
781
                }
782
                inode = iget(sb, EXT4_RESIZE_INO);
783
                if (!inode || is_bad_inode(inode)) {
784
                        ext4_warning(sb, __FUNCTION__,
785
                                     "Error opening resize inode");
786
                        iput(inode);
787
                        return -ENOENT;
788
                }
789
        }
790
 
791
        if ((err = verify_group_input(sb, input)))
792
                goto exit_put;
793
 
794
        if ((err = setup_new_group_blocks(sb, input)))
795
                goto exit_put;
796
 
797
        /*
798
         * We will always be modifying at least the superblock and a GDT
799
         * block.  If we are adding a group past the last current GDT block,
800
         * we will also modify the inode and the dindirect block.  If we
801
         * are adding a group with superblock/GDT backups  we will also
802
         * modify each of the reserved GDT dindirect blocks.
803
         */
804
        handle = ext4_journal_start_sb(sb,
805
                                       ext4_bg_has_super(sb, input->group) ?
806
                                       3 + reserved_gdb : 4);
807
        if (IS_ERR(handle)) {
808
                err = PTR_ERR(handle);
809
                goto exit_put;
810
        }
811
 
812
        lock_super(sb);
813
        if (input->group != sbi->s_groups_count) {
814
                ext4_warning(sb, __FUNCTION__,
815
                             "multiple resizers run on filesystem!");
816
                err = -EBUSY;
817
                goto exit_journal;
818
        }
819
 
820
        if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh)))
821
                goto exit_journal;
822
 
823
        /*
824
         * We will only either add reserved group blocks to a backup group
825
         * or remove reserved blocks for the first group in a new group block.
826
         * Doing both would be mean more complex code, and sane people don't
827
         * use non-sparse filesystems anymore.  This is already checked above.
828
         */
829
        if (gdb_off) {
830
                primary = sbi->s_group_desc[gdb_num];
831
                if ((err = ext4_journal_get_write_access(handle, primary)))
832
                        goto exit_journal;
833
 
834
                if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) &&
835
                    (err = reserve_backup_gdb(handle, inode, input)))
836
                        goto exit_journal;
837
        } else if ((err = add_new_gdb(handle, inode, input, &primary)))
838
                goto exit_journal;
839
 
840
        /*
841
         * OK, now we've set up the new group.  Time to make it active.
842
         *
843
         * Current kernels don't lock all allocations via lock_super(),
844
         * so we have to be safe wrt. concurrent accesses the group
845
         * data.  So we need to be careful to set all of the relevant
846
         * group descriptor data etc. *before* we enable the group.
847
         *
848
         * The key field here is sbi->s_groups_count: as long as
849
         * that retains its old value, nobody is going to access the new
850
         * group.
851
         *
852
         * So first we update all the descriptor metadata for the new
853
         * group; then we update the total disk blocks count; then we
854
         * update the groups count to enable the group; then finally we
855
         * update the free space counts so that the system can start
856
         * using the new disk blocks.
857
         */
858
 
859
        /* Update group descriptor block for new group */
860
        gdp = (struct ext4_group_desc *)primary->b_data + gdb_off;
861
 
862
        ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */
863
        ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */
864
        ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
865
        gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
866
        gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb));
867
        gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
868
 
869
        /*
870
         * Make the new blocks and inodes valid next.  We do this before
871
         * increasing the group count so that once the group is enabled,
872
         * all of its blocks and inodes are already valid.
873
         *
874
         * We always allocate group-by-group, then block-by-block or
875
         * inode-by-inode within a group, so enabling these
876
         * blocks/inodes before the group is live won't actually let us
877
         * allocate the new space yet.
878
         */
879
        ext4_blocks_count_set(es, ext4_blocks_count(es) +
880
                input->blocks_count);
881
        es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
882
                EXT4_INODES_PER_GROUP(sb));
883
 
884
        /*
885
         * We need to protect s_groups_count against other CPUs seeing
886
         * inconsistent state in the superblock.
887
         *
888
         * The precise rules we use are:
889
         *
890
         * * Writers of s_groups_count *must* hold lock_super
891
         * AND
892
         * * Writers must perform a smp_wmb() after updating all dependent
893
         *   data and before modifying the groups count
894
         *
895
         * * Readers must hold lock_super() over the access
896
         * OR
897
         * * Readers must perform an smp_rmb() after reading the groups count
898
         *   and before reading any dependent data.
899
         *
900
         * NB. These rules can be relaxed when checking the group count
901
         * while freeing data, as we can only allocate from a block
902
         * group after serialising against the group count, and we can
903
         * only then free after serialising in turn against that
904
         * allocation.
905
         */
906
        smp_wmb();
907
 
908
        /* Update the global fs size fields */
909
        sbi->s_groups_count++;
910
 
911
        ext4_journal_dirty_metadata(handle, primary);
912
 
913
        /* Update the reserved block counts only once the new group is
914
         * active. */
915
        ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
916
                input->reserved_blocks);
917
 
918
        /* Update the free space counts */
919
        percpu_counter_add(&sbi->s_freeblocks_counter,
920
                           input->free_blocks_count);
921
        percpu_counter_add(&sbi->s_freeinodes_counter,
922
                           EXT4_INODES_PER_GROUP(sb));
923
 
924
        ext4_journal_dirty_metadata(handle, sbi->s_sbh);
925
        sb->s_dirt = 1;
926
 
927
exit_journal:
928
        unlock_super(sb);
929
        if ((err2 = ext4_journal_stop(handle)) && !err)
930
                err = err2;
931
        if (!err) {
932
                update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
933
                               sizeof(struct ext4_super_block));
934
                update_backups(sb, primary->b_blocknr, primary->b_data,
935
                               primary->b_size);
936
        }
937
exit_put:
938
        iput(inode);
939
        return err;
940
} /* ext4_group_add */
941
 
942
/* Extend the filesystem to the new number of blocks specified.  This entry
943
 * point is only used to extend the current filesystem to the end of the last
944
 * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
945
 * for emergencies (because it has no dependencies on reserved blocks).
946
 *
947
 * If we _really_ wanted, we could use default values to call ext4_group_add()
948
 * allow the "remount" trick to work for arbitrary resizing, assuming enough
949
 * GDT blocks are reserved to grow to the desired size.
950
 */
951
int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
952
                      ext4_fsblk_t n_blocks_count)
953
{
954
        ext4_fsblk_t o_blocks_count;
955
        unsigned long o_groups_count;
956
        ext4_grpblk_t last;
957
        ext4_grpblk_t add;
958
        struct buffer_head * bh;
959
        handle_t *handle;
960
        int err;
961
        unsigned long freed_blocks;
962
 
963
        /* We don't need to worry about locking wrt other resizers just
964
         * yet: we're going to revalidate es->s_blocks_count after
965
         * taking lock_super() below. */
966
        o_blocks_count = ext4_blocks_count(es);
967
        o_groups_count = EXT4_SB(sb)->s_groups_count;
968
 
969
        if (test_opt(sb, DEBUG))
970
                printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n",
971
                       o_blocks_count, n_blocks_count);
972
 
973
        if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
974
                return 0;
975
 
976
        if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
977
                printk(KERN_ERR "EXT4-fs: filesystem on %s:"
978
                        " too large to resize to %llu blocks safely\n",
979
                        sb->s_id, n_blocks_count);
980
                if (sizeof(sector_t) < 8)
981
                        ext4_warning(sb, __FUNCTION__,
982
                        "CONFIG_LBD not enabled\n");
983
                return -EINVAL;
984
        }
985
 
986
        if (n_blocks_count < o_blocks_count) {
987
                ext4_warning(sb, __FUNCTION__,
988
                             "can't shrink FS - resize aborted");
989
                return -EBUSY;
990
        }
991
 
992
        /* Handle the remaining blocks in the last group only. */
993
        ext4_get_group_no_and_offset(sb, o_blocks_count, NULL, &last);
994
 
995
        if (last == 0) {
996
                ext4_warning(sb, __FUNCTION__,
997
                             "need to use ext2online to resize further");
998
                return -EPERM;
999
        }
1000
 
1001
        add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1002
 
1003
        if (o_blocks_count + add < o_blocks_count) {
1004
                ext4_warning(sb, __FUNCTION__, "blocks_count overflow");
1005
                return -EINVAL;
1006
        }
1007
 
1008
        if (o_blocks_count + add > n_blocks_count)
1009
                add = n_blocks_count - o_blocks_count;
1010
 
1011
        if (o_blocks_count + add < n_blocks_count)
1012
                ext4_warning(sb, __FUNCTION__,
1013
                             "will only finish group (%llu"
1014
                             " blocks, %u new)",
1015
                             o_blocks_count + add, add);
1016
 
1017
        /* See if the device is actually as big as what was requested */
1018
        bh = sb_bread(sb, o_blocks_count + add -1);
1019
        if (!bh) {
1020
                ext4_warning(sb, __FUNCTION__,
1021
                             "can't read last block, resize aborted");
1022
                return -ENOSPC;
1023
        }
1024
        brelse(bh);
1025
 
1026
        /* We will update the superblock, one block bitmap, and
1027
         * one group descriptor via ext4_free_blocks().
1028
         */
1029
        handle = ext4_journal_start_sb(sb, 3);
1030
        if (IS_ERR(handle)) {
1031
                err = PTR_ERR(handle);
1032
                ext4_warning(sb, __FUNCTION__, "error %d on journal start",err);
1033
                goto exit_put;
1034
        }
1035
 
1036
        lock_super(sb);
1037
        if (o_blocks_count != ext4_blocks_count(es)) {
1038
                ext4_warning(sb, __FUNCTION__,
1039
                             "multiple resizers run on filesystem!");
1040
                unlock_super(sb);
1041
                err = -EBUSY;
1042
                goto exit_put;
1043
        }
1044
 
1045
        if ((err = ext4_journal_get_write_access(handle,
1046
                                                 EXT4_SB(sb)->s_sbh))) {
1047
                ext4_warning(sb, __FUNCTION__,
1048
                             "error %d on journal write access", err);
1049
                unlock_super(sb);
1050
                ext4_journal_stop(handle);
1051
                goto exit_put;
1052
        }
1053
        ext4_blocks_count_set(es, o_blocks_count + add);
1054
        ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
1055
        sb->s_dirt = 1;
1056
        unlock_super(sb);
1057
        ext4_debug("freeing blocks %lu through %llu\n", o_blocks_count,
1058
                   o_blocks_count + add);
1059
        ext4_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1060
        ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1061
                   o_blocks_count + add);
1062
        if ((err = ext4_journal_stop(handle)))
1063
                goto exit_put;
1064
        if (test_opt(sb, DEBUG))
1065
                printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
1066
                       ext4_blocks_count(es));
1067
        update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1068
                       sizeof(struct ext4_super_block));
1069
exit_put:
1070
        return err;
1071
} /* ext4_group_extend */

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