ext4: convert number of blocks to clusters properly
[linux-2.6.git] / fs / ext4 / resize.c
1 /*
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/errno.h>
15 #include <linux/slab.h>
16
17 #include "ext4_jbd2.h"
18
19 int ext4_resize_begin(struct super_block *sb)
20 {
21         int ret = 0;
22
23         if (!capable(CAP_SYS_RESOURCE))
24                 return -EPERM;
25
26         /*
27          * We are not allowed to do online-resizing on a filesystem mounted
28          * with error, because it can destroy the filesystem easily.
29          */
30         if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
31                 ext4_warning(sb, "There are errors in the filesystem, "
32                              "so online resizing is not allowed\n");
33                 return -EPERM;
34         }
35
36         if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
37                 ret = -EBUSY;
38
39         return ret;
40 }
41
42 void ext4_resize_end(struct super_block *sb)
43 {
44         clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
45         smp_mb__after_clear_bit();
46 }
47
48 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
49 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
50
51 static int verify_group_input(struct super_block *sb,
52                               struct ext4_new_group_data *input)
53 {
54         struct ext4_sb_info *sbi = EXT4_SB(sb);
55         struct ext4_super_block *es = sbi->s_es;
56         ext4_fsblk_t start = ext4_blocks_count(es);
57         ext4_fsblk_t end = start + input->blocks_count;
58         ext4_group_t group = input->group;
59         ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
60         unsigned overhead = ext4_bg_has_super(sb, group) ?
61                 (1 + ext4_bg_num_gdb(sb, group) +
62                  le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
63         ext4_fsblk_t metaend = start + overhead;
64         struct buffer_head *bh = NULL;
65         ext4_grpblk_t free_blocks_count, offset;
66         int err = -EINVAL;
67
68         input->free_blocks_count = free_blocks_count =
69                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
70
71         if (test_opt(sb, DEBUG))
72                 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
73                        "(%d free, %u reserved)\n",
74                        ext4_bg_has_super(sb, input->group) ? "normal" :
75                        "no-super", input->group, input->blocks_count,
76                        free_blocks_count, input->reserved_blocks);
77
78         ext4_get_group_no_and_offset(sb, start, NULL, &offset);
79         if (group != sbi->s_groups_count)
80                 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
81                              input->group, sbi->s_groups_count);
82         else if (offset != 0)
83                         ext4_warning(sb, "Last group not full");
84         else if (input->reserved_blocks > input->blocks_count / 5)
85                 ext4_warning(sb, "Reserved blocks too high (%u)",
86                              input->reserved_blocks);
87         else if (free_blocks_count < 0)
88                 ext4_warning(sb, "Bad blocks count %u",
89                              input->blocks_count);
90         else if (!(bh = sb_bread(sb, end - 1)))
91                 ext4_warning(sb, "Cannot read last block (%llu)",
92                              end - 1);
93         else if (outside(input->block_bitmap, start, end))
94                 ext4_warning(sb, "Block bitmap not in group (block %llu)",
95                              (unsigned long long)input->block_bitmap);
96         else if (outside(input->inode_bitmap, start, end))
97                 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
98                              (unsigned long long)input->inode_bitmap);
99         else if (outside(input->inode_table, start, end) ||
100                  outside(itend - 1, start, end))
101                 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
102                              (unsigned long long)input->inode_table, itend - 1);
103         else if (input->inode_bitmap == input->block_bitmap)
104                 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
105                              (unsigned long long)input->block_bitmap);
106         else if (inside(input->block_bitmap, input->inode_table, itend))
107                 ext4_warning(sb, "Block bitmap (%llu) in inode table "
108                              "(%llu-%llu)",
109                              (unsigned long long)input->block_bitmap,
110                              (unsigned long long)input->inode_table, itend - 1);
111         else if (inside(input->inode_bitmap, input->inode_table, itend))
112                 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
113                              "(%llu-%llu)",
114                              (unsigned long long)input->inode_bitmap,
115                              (unsigned long long)input->inode_table, itend - 1);
116         else if (inside(input->block_bitmap, start, metaend))
117                 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
118                              (unsigned long long)input->block_bitmap,
119                              start, metaend - 1);
120         else if (inside(input->inode_bitmap, start, metaend))
121                 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
122                              (unsigned long long)input->inode_bitmap,
123                              start, metaend - 1);
124         else if (inside(input->inode_table, start, metaend) ||
125                  inside(itend - 1, start, metaend))
126                 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
127                              "(%llu-%llu)",
128                              (unsigned long long)input->inode_table,
129                              itend - 1, start, metaend - 1);
130         else
131                 err = 0;
132         brelse(bh);
133
134         return err;
135 }
136
137 /*
138  * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
139  * group each time.
140  */
141 struct ext4_new_flex_group_data {
142         struct ext4_new_group_data *groups;     /* new_group_data for groups
143                                                    in the flex group */
144         __u16 *bg_flags;                        /* block group flags of groups
145                                                    in @groups */
146         ext4_group_t count;                     /* number of groups in @groups
147                                                  */
148 };
149
150 /*
151  * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
152  * @flexbg_size.
153  *
154  * Returns NULL on failure otherwise address of the allocated structure.
155  */
156 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
157 {
158         struct ext4_new_flex_group_data *flex_gd;
159
160         flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
161         if (flex_gd == NULL)
162                 goto out3;
163
164         if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
165                 goto out2;
166         flex_gd->count = flexbg_size;
167
168         flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *
169                                   flexbg_size, GFP_NOFS);
170         if (flex_gd->groups == NULL)
171                 goto out2;
172
173         flex_gd->bg_flags = kmalloc(flexbg_size * sizeof(__u16), GFP_NOFS);
174         if (flex_gd->bg_flags == NULL)
175                 goto out1;
176
177         return flex_gd;
178
179 out1:
180         kfree(flex_gd->groups);
181 out2:
182         kfree(flex_gd);
183 out3:
184         return NULL;
185 }
186
187 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
188 {
189         kfree(flex_gd->bg_flags);
190         kfree(flex_gd->groups);
191         kfree(flex_gd);
192 }
193
194 /*
195  * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
196  * and inode tables for a flex group.
197  *
198  * This function is used by 64bit-resize.  Note that this function allocates
199  * group tables from the 1st group of groups contained by @flexgd, which may
200  * be a partial of a flex group.
201  *
202  * @sb: super block of fs to which the groups belongs
203  *
204  * Returns 0 on a successful allocation of the metadata blocks in the
205  * block group.
206  */
207 static int ext4_alloc_group_tables(struct super_block *sb,
208                                 struct ext4_new_flex_group_data *flex_gd,
209                                 int flexbg_size)
210 {
211         struct ext4_new_group_data *group_data = flex_gd->groups;
212         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
213         ext4_fsblk_t start_blk;
214         ext4_fsblk_t last_blk;
215         ext4_group_t src_group;
216         ext4_group_t bb_index = 0;
217         ext4_group_t ib_index = 0;
218         ext4_group_t it_index = 0;
219         ext4_group_t group;
220         ext4_group_t last_group;
221         unsigned overhead;
222
223         BUG_ON(flex_gd->count == 0 || group_data == NULL);
224
225         src_group = group_data[0].group;
226         last_group  = src_group + flex_gd->count - 1;
227
228         BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
229                (last_group & ~(flexbg_size - 1))));
230 next_group:
231         group = group_data[0].group;
232         if (src_group >= group_data[0].group + flex_gd->count)
233                 return -ENOSPC;
234         start_blk = ext4_group_first_block_no(sb, src_group);
235         last_blk = start_blk + group_data[src_group - group].blocks_count;
236
237         overhead = ext4_bg_has_super(sb, src_group) ?
238                    (1 + ext4_bg_num_gdb(sb, src_group) +
239                     le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
240
241         start_blk += overhead;
242
243         /* We collect contiguous blocks as much as possible. */
244         src_group++;
245         for (; src_group <= last_group; src_group++)
246                 if (!ext4_bg_has_super(sb, src_group))
247                         last_blk += group_data[src_group - group].blocks_count;
248                 else
249                         break;
250
251         /* Allocate block bitmaps */
252         for (; bb_index < flex_gd->count; bb_index++) {
253                 if (start_blk >= last_blk)
254                         goto next_group;
255                 group_data[bb_index].block_bitmap = start_blk++;
256                 ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
257                 group -= group_data[0].group;
258                 group_data[group].free_blocks_count--;
259                 if (flexbg_size > 1)
260                         flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
261         }
262
263         /* Allocate inode bitmaps */
264         for (; ib_index < flex_gd->count; ib_index++) {
265                 if (start_blk >= last_blk)
266                         goto next_group;
267                 group_data[ib_index].inode_bitmap = start_blk++;
268                 ext4_get_group_no_and_offset(sb, start_blk - 1, &group, NULL);
269                 group -= group_data[0].group;
270                 group_data[group].free_blocks_count--;
271                 if (flexbg_size > 1)
272                         flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
273         }
274
275         /* Allocate inode tables */
276         for (; it_index < flex_gd->count; it_index++) {
277                 if (start_blk + EXT4_SB(sb)->s_itb_per_group > last_blk)
278                         goto next_group;
279                 group_data[it_index].inode_table = start_blk;
280                 ext4_get_group_no_and_offset(sb, start_blk, &group, NULL);
281                 group -= group_data[0].group;
282                 group_data[group].free_blocks_count -=
283                                         EXT4_SB(sb)->s_itb_per_group;
284                 if (flexbg_size > 1)
285                         flex_gd->bg_flags[group] &= ~EXT4_BG_BLOCK_UNINIT;
286
287                 start_blk += EXT4_SB(sb)->s_itb_per_group;
288         }
289
290         if (test_opt(sb, DEBUG)) {
291                 int i;
292                 group = group_data[0].group;
293
294                 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
295                        "%d groups, flexbg size is %d:\n", flex_gd->count,
296                        flexbg_size);
297
298                 for (i = 0; i < flex_gd->count; i++) {
299                         printk(KERN_DEBUG "adding %s group %u: %u "
300                                "blocks (%d free)\n",
301                                ext4_bg_has_super(sb, group + i) ? "normal" :
302                                "no-super", group + i,
303                                group_data[i].blocks_count,
304                                group_data[i].free_blocks_count);
305                 }
306         }
307         return 0;
308 }
309
310 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
311                                   ext4_fsblk_t blk)
312 {
313         struct buffer_head *bh;
314         int err;
315
316         bh = sb_getblk(sb, blk);
317         if (!bh)
318                 return ERR_PTR(-EIO);
319         if ((err = ext4_journal_get_write_access(handle, bh))) {
320                 brelse(bh);
321                 bh = ERR_PTR(err);
322         } else {
323                 memset(bh->b_data, 0, sb->s_blocksize);
324                 set_buffer_uptodate(bh);
325         }
326
327         return bh;
328 }
329
330 /*
331  * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
332  * If that fails, restart the transaction & regain write access for the
333  * buffer head which is used for block_bitmap modifications.
334  */
335 static int extend_or_restart_transaction(handle_t *handle, int thresh)
336 {
337         int err;
338
339         if (ext4_handle_has_enough_credits(handle, thresh))
340                 return 0;
341
342         err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
343         if (err < 0)
344                 return err;
345         if (err) {
346                 err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
347                 if (err)
348                         return err;
349         }
350
351         return 0;
352 }
353
354 /*
355  * set_flexbg_block_bitmap() mark @count blocks starting from @block used.
356  *
357  * Helper function for ext4_setup_new_group_blocks() which set .
358  *
359  * @sb: super block
360  * @handle: journal handle
361  * @flex_gd: flex group data
362  */
363 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
364                         struct ext4_new_flex_group_data *flex_gd,
365                         ext4_fsblk_t block, ext4_group_t count)
366 {
367         ext4_group_t count2;
368
369         ext4_debug("mark blocks [%llu/%u] used\n", block, count);
370         for (count2 = count; count > 0; count -= count2, block += count2) {
371                 ext4_fsblk_t start;
372                 struct buffer_head *bh;
373                 ext4_group_t group;
374                 int err;
375
376                 ext4_get_group_no_and_offset(sb, block, &group, NULL);
377                 start = ext4_group_first_block_no(sb, group);
378                 group -= flex_gd->groups[0].group;
379
380                 count2 = sb->s_blocksize * 8 - (block - start);
381                 if (count2 > count)
382                         count2 = count;
383
384                 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
385                         BUG_ON(flex_gd->count > 1);
386                         continue;
387                 }
388
389                 err = extend_or_restart_transaction(handle, 1);
390                 if (err)
391                         return err;
392
393                 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
394                 if (!bh)
395                         return -EIO;
396
397                 err = ext4_journal_get_write_access(handle, bh);
398                 if (err)
399                         return err;
400                 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", block,
401                            block - start, count2);
402                 ext4_set_bits(bh->b_data, block - start, count2);
403
404                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
405                 if (unlikely(err))
406                         return err;
407                 brelse(bh);
408         }
409
410         return 0;
411 }
412
413 /*
414  * Set up the block and inode bitmaps, and the inode table for the new groups.
415  * This doesn't need to be part of the main transaction, since we are only
416  * changing blocks outside the actual filesystem.  We still do journaling to
417  * ensure the recovery is correct in case of a failure just after resize.
418  * If any part of this fails, we simply abort the resize.
419  *
420  * setup_new_flex_group_blocks handles a flex group as follow:
421  *  1. copy super block and GDT, and initialize group tables if necessary.
422  *     In this step, we only set bits in blocks bitmaps for blocks taken by
423  *     super block and GDT.
424  *  2. allocate group tables in block bitmaps, that is, set bits in block
425  *     bitmap for blocks taken by group tables.
426  */
427 static int setup_new_flex_group_blocks(struct super_block *sb,
428                                 struct ext4_new_flex_group_data *flex_gd)
429 {
430         int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
431         ext4_fsblk_t start;
432         ext4_fsblk_t block;
433         struct ext4_sb_info *sbi = EXT4_SB(sb);
434         struct ext4_super_block *es = sbi->s_es;
435         struct ext4_new_group_data *group_data = flex_gd->groups;
436         __u16 *bg_flags = flex_gd->bg_flags;
437         handle_t *handle;
438         ext4_group_t group, count;
439         struct buffer_head *bh = NULL;
440         int reserved_gdb, i, j, err = 0, err2;
441
442         BUG_ON(!flex_gd->count || !group_data ||
443                group_data[0].group != sbi->s_groups_count);
444
445         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
446
447         /* This transaction may be extended/restarted along the way */
448         handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
449         if (IS_ERR(handle))
450                 return PTR_ERR(handle);
451
452         group = group_data[0].group;
453         for (i = 0; i < flex_gd->count; i++, group++) {
454                 unsigned long gdblocks;
455
456                 gdblocks = ext4_bg_num_gdb(sb, group);
457                 start = ext4_group_first_block_no(sb, group);
458
459                 if (!ext4_bg_has_super(sb, group))
460                         goto handle_itb;
461
462                 /* Copy all of the GDT blocks into the backup in this group */
463                 for (j = 0, block = start + 1; j < gdblocks; j++, block++) {
464                         struct buffer_head *gdb;
465
466                         ext4_debug("update backup group %#04llx\n", block);
467                         err = extend_or_restart_transaction(handle, 1);
468                         if (err)
469                                 goto out;
470
471                         gdb = sb_getblk(sb, block);
472                         if (!gdb) {
473                                 err = -EIO;
474                                 goto out;
475                         }
476
477                         err = ext4_journal_get_write_access(handle, gdb);
478                         if (err) {
479                                 brelse(gdb);
480                                 goto out;
481                         }
482                         memcpy(gdb->b_data, sbi->s_group_desc[j]->b_data,
483                                gdb->b_size);
484                         set_buffer_uptodate(gdb);
485
486                         err = ext4_handle_dirty_metadata(handle, NULL, gdb);
487                         if (unlikely(err)) {
488                                 brelse(gdb);
489                                 goto out;
490                         }
491                         brelse(gdb);
492                 }
493
494                 /* Zero out all of the reserved backup group descriptor
495                  * table blocks
496                  */
497                 if (ext4_bg_has_super(sb, group)) {
498                         err = sb_issue_zeroout(sb, gdblocks + start + 1,
499                                         reserved_gdb, GFP_NOFS);
500                         if (err)
501                                 goto out;
502                 }
503
504 handle_itb:
505                 /* Initialize group tables of the grop @group */
506                 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
507                         goto handle_bb;
508
509                 /* Zero out all of the inode table blocks */
510                 block = group_data[i].inode_table;
511                 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
512                            block, sbi->s_itb_per_group);
513                 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
514                                        GFP_NOFS);
515                 if (err)
516                         goto out;
517
518 handle_bb:
519                 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
520                         goto handle_ib;
521
522                 /* Initialize block bitmap of the @group */
523                 block = group_data[i].block_bitmap;
524                 err = extend_or_restart_transaction(handle, 1);
525                 if (err)
526                         goto out;
527
528                 bh = bclean(handle, sb, block);
529                 if (IS_ERR(bh)) {
530                         err = PTR_ERR(bh);
531                         goto out;
532                 }
533                 if (ext4_bg_has_super(sb, group)) {
534                         ext4_debug("mark backup superblock %#04llx (+0)\n",
535                                    start);
536                         ext4_set_bits(bh->b_data, 0, gdblocks + reserved_gdb +
537                                                      1);
538                 }
539                 ext4_mark_bitmap_end(group_data[i].blocks_count,
540                                      sb->s_blocksize * 8, bh->b_data);
541                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
542                 if (err)
543                         goto out;
544                 brelse(bh);
545
546 handle_ib:
547                 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
548                         continue;
549
550                 /* Initialize inode bitmap of the @group */
551                 block = group_data[i].inode_bitmap;
552                 err = extend_or_restart_transaction(handle, 1);
553                 if (err)
554                         goto out;
555                 /* Mark unused entries in inode bitmap used */
556                 bh = bclean(handle, sb, block);
557                 if (IS_ERR(bh)) {
558                         err = PTR_ERR(bh);
559                         goto out;
560                 }
561
562                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
563                                      sb->s_blocksize * 8, bh->b_data);
564                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
565                 if (err)
566                         goto out;
567                 brelse(bh);
568         }
569         bh = NULL;
570
571         /* Mark group tables in block bitmap */
572         for (j = 0; j < GROUP_TABLE_COUNT; j++) {
573                 count = group_table_count[j];
574                 start = (&group_data[0].block_bitmap)[j];
575                 block = start;
576                 for (i = 1; i < flex_gd->count; i++) {
577                         block += group_table_count[j];
578                         if (block == (&group_data[i].block_bitmap)[j]) {
579                                 count += group_table_count[j];
580                                 continue;
581                         }
582                         err = set_flexbg_block_bitmap(sb, handle,
583                                                 flex_gd, start, count);
584                         if (err)
585                                 goto out;
586                         count = group_table_count[j];
587                         start = group_data[i].block_bitmap;
588                         block = start;
589                 }
590
591                 if (count) {
592                         err = set_flexbg_block_bitmap(sb, handle,
593                                                 flex_gd, start, count);
594                         if (err)
595                                 goto out;
596                 }
597         }
598
599 out:
600         brelse(bh);
601         err2 = ext4_journal_stop(handle);
602         if (err2 && !err)
603                 err = err2;
604
605         return err;
606 }
607
608 /*
609  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
610  * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
611  * calling this for the first time.  In a sparse filesystem it will be the
612  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
613  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
614  */
615 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
616                                   unsigned *five, unsigned *seven)
617 {
618         unsigned *min = three;
619         int mult = 3;
620         unsigned ret;
621
622         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
623                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
624                 ret = *min;
625                 *min += 1;
626                 return ret;
627         }
628
629         if (*five < *min) {
630                 min = five;
631                 mult = 5;
632         }
633         if (*seven < *min) {
634                 min = seven;
635                 mult = 7;
636         }
637
638         ret = *min;
639         *min *= mult;
640
641         return ret;
642 }
643
644 /*
645  * Check that all of the backup GDT blocks are held in the primary GDT block.
646  * It is assumed that they are stored in group order.  Returns the number of
647  * groups in current filesystem that have BACKUPS, or -ve error code.
648  */
649 static int verify_reserved_gdb(struct super_block *sb,
650                                ext4_group_t end,
651                                struct buffer_head *primary)
652 {
653         const ext4_fsblk_t blk = primary->b_blocknr;
654         unsigned three = 1;
655         unsigned five = 5;
656         unsigned seven = 7;
657         unsigned grp;
658         __le32 *p = (__le32 *)primary->b_data;
659         int gdbackups = 0;
660
661         while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
662                 if (le32_to_cpu(*p++) !=
663                     grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
664                         ext4_warning(sb, "reserved GDT %llu"
665                                      " missing grp %d (%llu)",
666                                      blk, grp,
667                                      grp *
668                                      (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
669                                      blk);
670                         return -EINVAL;
671                 }
672                 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
673                         return -EFBIG;
674         }
675
676         return gdbackups;
677 }
678
679 /*
680  * Called when we need to bring a reserved group descriptor table block into
681  * use from the resize inode.  The primary copy of the new GDT block currently
682  * is an indirect block (under the double indirect block in the resize inode).
683  * The new backup GDT blocks will be stored as leaf blocks in this indirect
684  * block, in group order.  Even though we know all the block numbers we need,
685  * we check to ensure that the resize inode has actually reserved these blocks.
686  *
687  * Don't need to update the block bitmaps because the blocks are still in use.
688  *
689  * We get all of the error cases out of the way, so that we are sure to not
690  * fail once we start modifying the data on disk, because JBD has no rollback.
691  */
692 static int add_new_gdb(handle_t *handle, struct inode *inode,
693                        ext4_group_t group)
694 {
695         struct super_block *sb = inode->i_sb;
696         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
697         unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
698         ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
699         struct buffer_head **o_group_desc, **n_group_desc;
700         struct buffer_head *dind;
701         struct buffer_head *gdb_bh;
702         int gdbackups;
703         struct ext4_iloc iloc;
704         __le32 *data;
705         int err;
706
707         if (test_opt(sb, DEBUG))
708                 printk(KERN_DEBUG
709                        "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
710                        gdb_num);
711
712         /*
713          * If we are not using the primary superblock/GDT copy don't resize,
714          * because the user tools have no way of handling this.  Probably a
715          * bad time to do it anyways.
716          */
717         if (EXT4_SB(sb)->s_sbh->b_blocknr !=
718             le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
719                 ext4_warning(sb, "won't resize using backup superblock at %llu",
720                         (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
721                 return -EPERM;
722         }
723
724         gdb_bh = sb_bread(sb, gdblock);
725         if (!gdb_bh)
726                 return -EIO;
727
728         gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
729         if (gdbackups < 0) {
730                 err = gdbackups;
731                 goto exit_bh;
732         }
733
734         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
735         dind = sb_bread(sb, le32_to_cpu(*data));
736         if (!dind) {
737                 err = -EIO;
738                 goto exit_bh;
739         }
740
741         data = (__le32 *)dind->b_data;
742         if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
743                 ext4_warning(sb, "new group %u GDT block %llu not reserved",
744                              group, gdblock);
745                 err = -EINVAL;
746                 goto exit_dind;
747         }
748
749         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
750         if (unlikely(err))
751                 goto exit_dind;
752
753         err = ext4_journal_get_write_access(handle, gdb_bh);
754         if (unlikely(err))
755                 goto exit_sbh;
756
757         err = ext4_journal_get_write_access(handle, dind);
758         if (unlikely(err))
759                 ext4_std_error(sb, err);
760
761         /* ext4_reserve_inode_write() gets a reference on the iloc */
762         err = ext4_reserve_inode_write(handle, inode, &iloc);
763         if (unlikely(err))
764                 goto exit_dindj;
765
766         n_group_desc = ext4_kvmalloc((gdb_num + 1) *
767                                      sizeof(struct buffer_head *),
768                                      GFP_NOFS);
769         if (!n_group_desc) {
770                 err = -ENOMEM;
771                 ext4_warning(sb, "not enough memory for %lu groups",
772                              gdb_num + 1);
773                 goto exit_inode;
774         }
775
776         /*
777          * Finally, we have all of the possible failures behind us...
778          *
779          * Remove new GDT block from inode double-indirect block and clear out
780          * the new GDT block for use (which also "frees" the backup GDT blocks
781          * from the reserved inode).  We don't need to change the bitmaps for
782          * these blocks, because they are marked as in-use from being in the
783          * reserved inode, and will become GDT blocks (primary and backup).
784          */
785         data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
786         err = ext4_handle_dirty_metadata(handle, NULL, dind);
787         if (unlikely(err)) {
788                 ext4_std_error(sb, err);
789                 goto exit_inode;
790         }
791         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
792         ext4_mark_iloc_dirty(handle, inode, &iloc);
793         memset(gdb_bh->b_data, 0, sb->s_blocksize);
794         err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
795         if (unlikely(err)) {
796                 ext4_std_error(sb, err);
797                 goto exit_inode;
798         }
799         brelse(dind);
800
801         o_group_desc = EXT4_SB(sb)->s_group_desc;
802         memcpy(n_group_desc, o_group_desc,
803                EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
804         n_group_desc[gdb_num] = gdb_bh;
805         EXT4_SB(sb)->s_group_desc = n_group_desc;
806         EXT4_SB(sb)->s_gdb_count++;
807         ext4_kvfree(o_group_desc);
808
809         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
810         err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
811         if (err)
812                 ext4_std_error(sb, err);
813
814         return err;
815
816 exit_inode:
817         ext4_kvfree(n_group_desc);
818         /* ext4_handle_release_buffer(handle, iloc.bh); */
819         brelse(iloc.bh);
820 exit_dindj:
821         /* ext4_handle_release_buffer(handle, dind); */
822 exit_sbh:
823         /* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
824 exit_dind:
825         brelse(dind);
826 exit_bh:
827         brelse(gdb_bh);
828
829         ext4_debug("leaving with error %d\n", err);
830         return err;
831 }
832
833 /*
834  * Called when we are adding a new group which has a backup copy of each of
835  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
836  * We need to add these reserved backup GDT blocks to the resize inode, so
837  * that they are kept for future resizing and not allocated to files.
838  *
839  * Each reserved backup GDT block will go into a different indirect block.
840  * The indirect blocks are actually the primary reserved GDT blocks,
841  * so we know in advance what their block numbers are.  We only get the
842  * double-indirect block to verify it is pointing to the primary reserved
843  * GDT blocks so we don't overwrite a data block by accident.  The reserved
844  * backup GDT blocks are stored in their reserved primary GDT block.
845  */
846 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
847                               ext4_group_t group)
848 {
849         struct super_block *sb = inode->i_sb;
850         int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
851         struct buffer_head **primary;
852         struct buffer_head *dind;
853         struct ext4_iloc iloc;
854         ext4_fsblk_t blk;
855         __le32 *data, *end;
856         int gdbackups = 0;
857         int res, i;
858         int err;
859
860         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
861         if (!primary)
862                 return -ENOMEM;
863
864         data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
865         dind = sb_bread(sb, le32_to_cpu(*data));
866         if (!dind) {
867                 err = -EIO;
868                 goto exit_free;
869         }
870
871         blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
872         data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
873                                          EXT4_ADDR_PER_BLOCK(sb));
874         end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
875
876         /* Get each reserved primary GDT block and verify it holds backups */
877         for (res = 0; res < reserved_gdb; res++, blk++) {
878                 if (le32_to_cpu(*data) != blk) {
879                         ext4_warning(sb, "reserved block %llu"
880                                      " not at offset %ld",
881                                      blk,
882                                      (long)(data - (__le32 *)dind->b_data));
883                         err = -EINVAL;
884                         goto exit_bh;
885                 }
886                 primary[res] = sb_bread(sb, blk);
887                 if (!primary[res]) {
888                         err = -EIO;
889                         goto exit_bh;
890                 }
891                 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
892                 if (gdbackups < 0) {
893                         brelse(primary[res]);
894                         err = gdbackups;
895                         goto exit_bh;
896                 }
897                 if (++data >= end)
898                         data = (__le32 *)dind->b_data;
899         }
900
901         for (i = 0; i < reserved_gdb; i++) {
902                 if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
903                         /*
904                         int j;
905                         for (j = 0; j < i; j++)
906                                 ext4_handle_release_buffer(handle, primary[j]);
907                          */
908                         goto exit_bh;
909                 }
910         }
911
912         if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
913                 goto exit_bh;
914
915         /*
916          * Finally we can add each of the reserved backup GDT blocks from
917          * the new group to its reserved primary GDT block.
918          */
919         blk = group * EXT4_BLOCKS_PER_GROUP(sb);
920         for (i = 0; i < reserved_gdb; i++) {
921                 int err2;
922                 data = (__le32 *)primary[i]->b_data;
923                 /* printk("reserving backup %lu[%u] = %lu\n",
924                        primary[i]->b_blocknr, gdbackups,
925                        blk + primary[i]->b_blocknr); */
926                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
927                 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
928                 if (!err)
929                         err = err2;
930         }
931         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
932         ext4_mark_iloc_dirty(handle, inode, &iloc);
933
934 exit_bh:
935         while (--res >= 0)
936                 brelse(primary[res]);
937         brelse(dind);
938
939 exit_free:
940         kfree(primary);
941
942         return err;
943 }
944
945 /*
946  * Update the backup copies of the ext4 metadata.  These don't need to be part
947  * of the main resize transaction, because e2fsck will re-write them if there
948  * is a problem (basically only OOM will cause a problem).  However, we
949  * _should_ update the backups if possible, in case the primary gets trashed
950  * for some reason and we need to run e2fsck from a backup superblock.  The
951  * important part is that the new block and inode counts are in the backup
952  * superblocks, and the location of the new group metadata in the GDT backups.
953  *
954  * We do not need take the s_resize_lock for this, because these
955  * blocks are not otherwise touched by the filesystem code when it is
956  * mounted.  We don't need to worry about last changing from
957  * sbi->s_groups_count, because the worst that can happen is that we
958  * do not copy the full number of backups at this time.  The resize
959  * which changed s_groups_count will backup again.
960  */
961 static void update_backups(struct super_block *sb,
962                            int blk_off, char *data, int size)
963 {
964         struct ext4_sb_info *sbi = EXT4_SB(sb);
965         const ext4_group_t last = sbi->s_groups_count;
966         const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
967         unsigned three = 1;
968         unsigned five = 5;
969         unsigned seven = 7;
970         ext4_group_t group;
971         int rest = sb->s_blocksize - size;
972         handle_t *handle;
973         int err = 0, err2;
974
975         handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
976         if (IS_ERR(handle)) {
977                 group = 1;
978                 err = PTR_ERR(handle);
979                 goto exit_err;
980         }
981
982         while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
983                 struct buffer_head *bh;
984
985                 /* Out of journal space, and can't get more - abort - so sad */
986                 if (ext4_handle_valid(handle) &&
987                     handle->h_buffer_credits == 0 &&
988                     ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
989                     (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
990                         break;
991
992                 bh = sb_getblk(sb, group * bpg + blk_off);
993                 if (!bh) {
994                         err = -EIO;
995                         break;
996                 }
997                 ext4_debug("update metadata backup %#04lx\n",
998                           (unsigned long)bh->b_blocknr);
999                 if ((err = ext4_journal_get_write_access(handle, bh)))
1000                         break;
1001                 lock_buffer(bh);
1002                 memcpy(bh->b_data, data, size);
1003                 if (rest)
1004                         memset(bh->b_data + size, 0, rest);
1005                 set_buffer_uptodate(bh);
1006                 unlock_buffer(bh);
1007                 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1008                 if (unlikely(err))
1009                         ext4_std_error(sb, err);
1010                 brelse(bh);
1011         }
1012         if ((err2 = ext4_journal_stop(handle)) && !err)
1013                 err = err2;
1014
1015         /*
1016          * Ugh! Need to have e2fsck write the backup copies.  It is too
1017          * late to revert the resize, we shouldn't fail just because of
1018          * the backup copies (they are only needed in case of corruption).
1019          *
1020          * However, if we got here we have a journal problem too, so we
1021          * can't really start a transaction to mark the superblock.
1022          * Chicken out and just set the flag on the hope it will be written
1023          * to disk, and if not - we will simply wait until next fsck.
1024          */
1025 exit_err:
1026         if (err) {
1027                 ext4_warning(sb, "can't update backup for group %u (err %d), "
1028                              "forcing fsck on next reboot", group, err);
1029                 sbi->s_mount_state &= ~EXT4_VALID_FS;
1030                 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1031                 mark_buffer_dirty(sbi->s_sbh);
1032         }
1033 }
1034
1035 /*
1036  * ext4_add_new_descs() adds @count group descriptor of groups
1037  * starting at @group
1038  *
1039  * @handle: journal handle
1040  * @sb: super block
1041  * @group: the group no. of the first group desc to be added
1042  * @resize_inode: the resize inode
1043  * @count: number of group descriptors to be added
1044  */
1045 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1046                               ext4_group_t group, struct inode *resize_inode,
1047                               ext4_group_t count)
1048 {
1049         struct ext4_sb_info *sbi = EXT4_SB(sb);
1050         struct ext4_super_block *es = sbi->s_es;
1051         struct buffer_head *gdb_bh;
1052         int i, gdb_off, gdb_num, err = 0;
1053
1054         for (i = 0; i < count; i++, group++) {
1055                 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1056                         le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1057
1058                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1059                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1060
1061                 /*
1062                  * We will only either add reserved group blocks to a backup group
1063                  * or remove reserved blocks for the first group in a new group block.
1064                  * Doing both would be mean more complex code, and sane people don't
1065                  * use non-sparse filesystems anymore.  This is already checked above.
1066                  */
1067                 if (gdb_off) {
1068                         gdb_bh = sbi->s_group_desc[gdb_num];
1069                         err = ext4_journal_get_write_access(handle, gdb_bh);
1070
1071                         if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1072                                 err = reserve_backup_gdb(handle, resize_inode, group);
1073                 } else
1074                         err = add_new_gdb(handle, resize_inode, group);
1075                 if (err)
1076                         break;
1077         }
1078         return err;
1079 }
1080
1081 /*
1082  * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1083  */
1084 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1085                                 struct ext4_new_flex_group_data *flex_gd)
1086 {
1087         struct ext4_new_group_data      *group_data = flex_gd->groups;
1088         struct ext4_group_desc          *gdp;
1089         struct ext4_sb_info             *sbi = EXT4_SB(sb);
1090         struct buffer_head              *gdb_bh;
1091         ext4_group_t                    group;
1092         __u16                           *bg_flags = flex_gd->bg_flags;
1093         int                             i, gdb_off, gdb_num, err = 0;
1094         
1095
1096         for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1097                 group = group_data->group;
1098
1099                 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1100                 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1101
1102                 /*
1103                  * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1104                  */
1105                 gdb_bh = sbi->s_group_desc[gdb_num];
1106                 /* Update group descriptor block for new group */
1107                 gdp = (struct ext4_group_desc *)((char *)gdb_bh->b_data +
1108                                                  gdb_off * EXT4_DESC_SIZE(sb));
1109
1110                 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1111                 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1112                 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1113                 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1114                 ext4_free_group_clusters_set(sb, gdp,
1115                         EXT4_NUM_B2C(sbi, group_data->free_blocks_count));
1116                 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1117                 gdp->bg_flags = cpu_to_le16(*bg_flags);
1118                 gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
1119
1120                 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1121                 if (unlikely(err)) {
1122                         ext4_std_error(sb, err);
1123                         break;
1124                 }
1125
1126                 /*
1127                  * We can allocate memory for mb_alloc based on the new group
1128                  * descriptor
1129                  */
1130                 err = ext4_mb_add_groupinfo(sb, group, gdp);
1131                 if (err)
1132                         break;
1133         }
1134         return err;
1135 }
1136
1137 /*
1138  * ext4_update_super() updates the super block so that the newly added
1139  * groups can be seen by the filesystem.
1140  *
1141  * @sb: super block
1142  * @flex_gd: new added groups
1143  */
1144 static void ext4_update_super(struct super_block *sb,
1145                              struct ext4_new_flex_group_data *flex_gd)
1146 {
1147         ext4_fsblk_t blocks_count = 0;
1148         ext4_fsblk_t free_blocks = 0;
1149         ext4_fsblk_t reserved_blocks = 0;
1150         struct ext4_new_group_data *group_data = flex_gd->groups;
1151         struct ext4_sb_info *sbi = EXT4_SB(sb);
1152         struct ext4_super_block *es = sbi->s_es;
1153         int i, ret;
1154
1155         BUG_ON(flex_gd->count == 0 || group_data == NULL);
1156         /*
1157          * Make the new blocks and inodes valid next.  We do this before
1158          * increasing the group count so that once the group is enabled,
1159          * all of its blocks and inodes are already valid.
1160          *
1161          * We always allocate group-by-group, then block-by-block or
1162          * inode-by-inode within a group, so enabling these
1163          * blocks/inodes before the group is live won't actually let us
1164          * allocate the new space yet.
1165          */
1166         for (i = 0; i < flex_gd->count; i++) {
1167                 blocks_count += group_data[i].blocks_count;
1168                 free_blocks += group_data[i].free_blocks_count;
1169         }
1170
1171         reserved_blocks = ext4_r_blocks_count(es) * 100;
1172         do_div(reserved_blocks, ext4_blocks_count(es));
1173         reserved_blocks *= blocks_count;
1174         do_div(reserved_blocks, 100);
1175
1176         ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1177         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1178         le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1179                      flex_gd->count);
1180         le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1181                      flex_gd->count);
1182
1183         /*
1184          * We need to protect s_groups_count against other CPUs seeing
1185          * inconsistent state in the superblock.
1186          *
1187          * The precise rules we use are:
1188          *
1189          * * Writers must perform a smp_wmb() after updating all
1190          *   dependent data and before modifying the groups count
1191          *
1192          * * Readers must perform an smp_rmb() after reading the groups
1193          *   count and before reading any dependent data.
1194          *
1195          * NB. These rules can be relaxed when checking the group count
1196          * while freeing data, as we can only allocate from a block
1197          * group after serialising against the group count, and we can
1198          * only then free after serialising in turn against that
1199          * allocation.
1200          */
1201         smp_wmb();
1202
1203         /* Update the global fs size fields */
1204         sbi->s_groups_count += flex_gd->count;
1205
1206         /* Update the reserved block counts only once the new group is
1207          * active. */
1208         ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1209                                 reserved_blocks);
1210
1211         /* Update the free space counts */
1212         percpu_counter_add(&sbi->s_freeclusters_counter,
1213                            EXT4_NUM_B2C(sbi, free_blocks));
1214         percpu_counter_add(&sbi->s_freeinodes_counter,
1215                            EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1216
1217         if (EXT4_HAS_INCOMPAT_FEATURE(sb,
1218                                       EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1219             sbi->s_log_groups_per_flex) {
1220                 ext4_group_t flex_group;
1221                 flex_group = ext4_flex_group(sbi, group_data[0].group);
1222                 atomic_add(EXT4_NUM_B2C(sbi, free_blocks),
1223                            &sbi->s_flex_groups[flex_group].free_clusters);
1224                 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1225                            &sbi->s_flex_groups[flex_group].free_inodes);
1226         }
1227
1228         /*
1229          * Update the fs overhead information
1230          */
1231         ext4_calculate_overhead(sb);
1232
1233         if (test_opt(sb, DEBUG))
1234                 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1235                        "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1236                        blocks_count, free_blocks, reserved_blocks);
1237 }
1238
1239 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1240  * _before_ we start modifying the filesystem, because we cannot abort the
1241  * transaction and not have it write the data to disk.
1242  */
1243 static int ext4_flex_group_add(struct super_block *sb,
1244                                struct inode *resize_inode,
1245                                struct ext4_new_flex_group_data *flex_gd)
1246 {
1247         struct ext4_sb_info *sbi = EXT4_SB(sb);
1248         struct ext4_super_block *es = sbi->s_es;
1249         ext4_fsblk_t o_blocks_count;
1250         ext4_grpblk_t last;
1251         ext4_group_t group;
1252         handle_t *handle;
1253         unsigned reserved_gdb;
1254         int err = 0, err2 = 0, credit;
1255
1256         BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1257
1258         reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1259         o_blocks_count = ext4_blocks_count(es);
1260         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1261         BUG_ON(last);
1262
1263         err = setup_new_flex_group_blocks(sb, flex_gd);
1264         if (err)
1265                 goto exit;
1266         /*
1267          * We will always be modifying at least the superblock and  GDT
1268          * block.  If we are adding a group past the last current GDT block,
1269          * we will also modify the inode and the dindirect block.  If we
1270          * are adding a group with superblock/GDT backups  we will also
1271          * modify each of the reserved GDT dindirect blocks.
1272          */
1273         credit = flex_gd->count * 4 + reserved_gdb;
1274         handle = ext4_journal_start_sb(sb, credit);
1275         if (IS_ERR(handle)) {
1276                 err = PTR_ERR(handle);
1277                 goto exit;
1278         }
1279
1280         err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1281         if (err)
1282                 goto exit_journal;
1283
1284         group = flex_gd->groups[0].group;
1285         BUG_ON(group != EXT4_SB(sb)->s_groups_count);
1286         err = ext4_add_new_descs(handle, sb, group,
1287                                 resize_inode, flex_gd->count);
1288         if (err)
1289                 goto exit_journal;
1290
1291         err = ext4_setup_new_descs(handle, sb, flex_gd);
1292         if (err)
1293                 goto exit_journal;
1294
1295         ext4_update_super(sb, flex_gd);
1296
1297         err = ext4_handle_dirty_super(handle, sb);
1298
1299 exit_journal:
1300         err2 = ext4_journal_stop(handle);
1301         if (!err)
1302                 err = err2;
1303
1304         if (!err) {
1305                 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1306                 int gdb_num_end = ((group + flex_gd->count - 1) /
1307                                    EXT4_DESC_PER_BLOCK(sb));
1308
1309                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
1310                                sizeof(struct ext4_super_block));
1311                 for (; gdb_num <= gdb_num_end; gdb_num++) {
1312                         struct buffer_head *gdb_bh;
1313
1314                         gdb_bh = sbi->s_group_desc[gdb_num];
1315                         update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1316                                        gdb_bh->b_size);
1317                 }
1318         }
1319 exit:
1320         return err;
1321 }
1322
1323 static int ext4_setup_next_flex_gd(struct super_block *sb,
1324                                     struct ext4_new_flex_group_data *flex_gd,
1325                                     ext4_fsblk_t n_blocks_count,
1326                                     unsigned long flexbg_size)
1327 {
1328         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1329         struct ext4_new_group_data *group_data = flex_gd->groups;
1330         ext4_fsblk_t o_blocks_count;
1331         ext4_group_t n_group;
1332         ext4_group_t group;
1333         ext4_group_t last_group;
1334         ext4_grpblk_t last;
1335         ext4_grpblk_t blocks_per_group;
1336         unsigned long i;
1337
1338         blocks_per_group = EXT4_BLOCKS_PER_GROUP(sb);
1339
1340         o_blocks_count = ext4_blocks_count(es);
1341
1342         if (o_blocks_count == n_blocks_count)
1343                 return 0;
1344
1345         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1346         BUG_ON(last);
1347         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1348
1349         last_group = group | (flexbg_size - 1);
1350         if (last_group > n_group)
1351                 last_group = n_group;
1352
1353         flex_gd->count = last_group - group + 1;
1354
1355         for (i = 0; i < flex_gd->count; i++) {
1356                 int overhead;
1357
1358                 group_data[i].group = group + i;
1359                 group_data[i].blocks_count = blocks_per_group;
1360                 overhead = ext4_bg_has_super(sb, group + i) ?
1361                            (1 + ext4_bg_num_gdb(sb, group + i) +
1362                             le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
1363                 group_data[i].free_blocks_count = blocks_per_group - overhead;
1364                 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
1365                                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
1366                         flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1367                                                EXT4_BG_INODE_UNINIT;
1368                 else
1369                         flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1370         }
1371
1372         if (last_group == n_group &&
1373             EXT4_HAS_RO_COMPAT_FEATURE(sb,
1374                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
1375                 /* We need to initialize block bitmap of last group. */
1376                 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1377
1378         if ((last_group == n_group) && (last != blocks_per_group - 1)) {
1379                 group_data[i - 1].blocks_count = last + 1;
1380                 group_data[i - 1].free_blocks_count -= blocks_per_group-
1381                                         last - 1;
1382         }
1383
1384         return 1;
1385 }
1386
1387 /* Add group descriptor data to an existing or new group descriptor block.
1388  * Ensure we handle all possible error conditions _before_ we start modifying
1389  * the filesystem, because we cannot abort the transaction and not have it
1390  * write the data to disk.
1391  *
1392  * If we are on a GDT block boundary, we need to get the reserved GDT block.
1393  * Otherwise, we may need to add backup GDT blocks for a sparse group.
1394  *
1395  * We only need to hold the superblock lock while we are actually adding
1396  * in the new group's counts to the superblock.  Prior to that we have
1397  * not really "added" the group at all.  We re-check that we are still
1398  * adding in the last group in case things have changed since verifying.
1399  */
1400 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1401 {
1402         struct ext4_new_flex_group_data flex_gd;
1403         struct ext4_sb_info *sbi = EXT4_SB(sb);
1404         struct ext4_super_block *es = sbi->s_es;
1405         int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1406                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1407         struct inode *inode = NULL;
1408         int gdb_off, gdb_num;
1409         int err;
1410         __u16 bg_flags = 0;
1411
1412         gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
1413         gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1414
1415         if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
1416                                         EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
1417                 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1418                 return -EPERM;
1419         }
1420
1421         if (ext4_blocks_count(es) + input->blocks_count <
1422             ext4_blocks_count(es)) {
1423                 ext4_warning(sb, "blocks_count overflow");
1424                 return -EINVAL;
1425         }
1426
1427         if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1428             le32_to_cpu(es->s_inodes_count)) {
1429                 ext4_warning(sb, "inodes_count overflow");
1430                 return -EINVAL;
1431         }
1432
1433         if (reserved_gdb || gdb_off == 0) {
1434                 if (!EXT4_HAS_COMPAT_FEATURE(sb,
1435                                              EXT4_FEATURE_COMPAT_RESIZE_INODE)
1436                     || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1437                         ext4_warning(sb,
1438                                      "No reserved GDT blocks, can't resize");
1439                         return -EPERM;
1440                 }
1441                 inode = ext4_iget(sb, EXT4_RESIZE_INO);
1442                 if (IS_ERR(inode)) {
1443                         ext4_warning(sb, "Error opening resize inode");
1444                         return PTR_ERR(inode);
1445                 }
1446         }
1447
1448
1449         err = verify_group_input(sb, input);
1450         if (err)
1451                 goto out;
1452
1453         flex_gd.count = 1;
1454         flex_gd.groups = input;
1455         flex_gd.bg_flags = &bg_flags;
1456         err = ext4_flex_group_add(sb, inode, &flex_gd);
1457 out:
1458         iput(inode);
1459         return err;
1460 } /* ext4_group_add */
1461
1462 /*
1463  * extend a group without checking assuming that checking has been done.
1464  */
1465 static int ext4_group_extend_no_check(struct super_block *sb,
1466                                       ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1467 {
1468         struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1469         handle_t *handle;
1470         int err = 0, err2;
1471
1472         /* We will update the superblock, one block bitmap, and
1473          * one group descriptor via ext4_group_add_blocks().
1474          */
1475         handle = ext4_journal_start_sb(sb, 3);
1476         if (IS_ERR(handle)) {
1477                 err = PTR_ERR(handle);
1478                 ext4_warning(sb, "error %d on journal start", err);
1479                 return err;
1480         }
1481
1482         err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1483         if (err) {
1484                 ext4_warning(sb, "error %d on journal write access", err);
1485                 goto errout;
1486         }
1487
1488         ext4_blocks_count_set(es, o_blocks_count + add);
1489         ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1490         ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1491                    o_blocks_count + add);
1492         /* We add the blocks to the bitmap and set the group need init bit */
1493         err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1494         if (err)
1495                 goto errout;
1496         ext4_handle_dirty_super(handle, sb);
1497         ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1498                    o_blocks_count + add);
1499 errout:
1500         err2 = ext4_journal_stop(handle);
1501         if (err2 && !err)
1502                 err = err2;
1503
1504         if (!err) {
1505                 if (test_opt(sb, DEBUG))
1506                         printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1507                                "blocks\n", ext4_blocks_count(es));
1508                 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1509                                sizeof(struct ext4_super_block));
1510         }
1511         return err;
1512 }
1513
1514 /*
1515  * Extend the filesystem to the new number of blocks specified.  This entry
1516  * point is only used to extend the current filesystem to the end of the last
1517  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1518  * for emergencies (because it has no dependencies on reserved blocks).
1519  *
1520  * If we _really_ wanted, we could use default values to call ext4_group_add()
1521  * allow the "remount" trick to work for arbitrary resizing, assuming enough
1522  * GDT blocks are reserved to grow to the desired size.
1523  */
1524 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1525                       ext4_fsblk_t n_blocks_count)
1526 {
1527         ext4_fsblk_t o_blocks_count;
1528         ext4_grpblk_t last;
1529         ext4_grpblk_t add;
1530         struct buffer_head *bh;
1531         int err;
1532         ext4_group_t group;
1533
1534         o_blocks_count = ext4_blocks_count(es);
1535
1536         if (test_opt(sb, DEBUG))
1537                 ext4_msg(sb, KERN_DEBUG,
1538                          "extending last group from %llu to %llu blocks",
1539                          o_blocks_count, n_blocks_count);
1540
1541         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1542                 return 0;
1543
1544         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1545                 ext4_msg(sb, KERN_ERR,
1546                          "filesystem too large to resize to %llu blocks safely",
1547                          n_blocks_count);
1548                 if (sizeof(sector_t) < 8)
1549                         ext4_warning(sb, "CONFIG_LBDAF not enabled");
1550                 return -EINVAL;
1551         }
1552
1553         if (n_blocks_count < o_blocks_count) {
1554                 ext4_warning(sb, "can't shrink FS - resize aborted");
1555                 return -EINVAL;
1556         }
1557
1558         /* Handle the remaining blocks in the last group only. */
1559         ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1560
1561         if (last == 0) {
1562                 ext4_warning(sb, "need to use ext2online to resize further");
1563                 return -EPERM;
1564         }
1565
1566         add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1567
1568         if (o_blocks_count + add < o_blocks_count) {
1569                 ext4_warning(sb, "blocks_count overflow");
1570                 return -EINVAL;
1571         }
1572
1573         if (o_blocks_count + add > n_blocks_count)
1574                 add = n_blocks_count - o_blocks_count;
1575
1576         if (o_blocks_count + add < n_blocks_count)
1577                 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1578                              o_blocks_count + add, add);
1579
1580         /* See if the device is actually as big as what was requested */
1581         bh = sb_bread(sb, o_blocks_count + add - 1);
1582         if (!bh) {
1583                 ext4_warning(sb, "can't read last block, resize aborted");
1584                 return -ENOSPC;
1585         }
1586         brelse(bh);
1587
1588         err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1589         return err;
1590 } /* ext4_group_extend */
1591
1592 /*
1593  * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1594  *
1595  * @sb: super block of the fs to be resized
1596  * @n_blocks_count: the number of blocks resides in the resized fs
1597  */
1598 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1599 {
1600         struct ext4_new_flex_group_data *flex_gd = NULL;
1601         struct ext4_sb_info *sbi = EXT4_SB(sb);
1602         struct ext4_super_block *es = sbi->s_es;
1603         struct buffer_head *bh;
1604         struct inode *resize_inode;
1605         ext4_fsblk_t o_blocks_count;
1606         ext4_group_t o_group;
1607         ext4_group_t n_group;
1608         ext4_grpblk_t offset, add;
1609         unsigned long n_desc_blocks;
1610         unsigned long o_desc_blocks;
1611         unsigned long desc_blocks;
1612         int err = 0, flexbg_size = 1;
1613
1614         o_blocks_count = ext4_blocks_count(es);
1615
1616         if (test_opt(sb, DEBUG))
1617                 ext4_msg(sb, KERN_DEBUG, "resizing filesystem from %llu "
1618                        "to %llu blocks", o_blocks_count, n_blocks_count);
1619
1620         if (n_blocks_count < o_blocks_count) {
1621                 /* On-line shrinking not supported */
1622                 ext4_warning(sb, "can't shrink FS - resize aborted");
1623                 return -EINVAL;
1624         }
1625
1626         if (n_blocks_count == o_blocks_count)
1627                 /* Nothing need to do */
1628                 return 0;
1629
1630         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
1631         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
1632
1633         n_desc_blocks = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
1634                         EXT4_DESC_PER_BLOCK(sb);
1635         o_desc_blocks = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
1636                         EXT4_DESC_PER_BLOCK(sb);
1637         desc_blocks = n_desc_blocks - o_desc_blocks;
1638
1639         if (desc_blocks &&
1640             (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) ||
1641              le16_to_cpu(es->s_reserved_gdt_blocks) < desc_blocks)) {
1642                 ext4_warning(sb, "No reserved GDT blocks, can't resize");
1643                 return -EPERM;
1644         }
1645
1646         resize_inode = ext4_iget(sb, EXT4_RESIZE_INO);
1647         if (IS_ERR(resize_inode)) {
1648                 ext4_warning(sb, "Error opening resize inode");
1649                 return PTR_ERR(resize_inode);
1650         }
1651
1652         /* See if the device is actually as big as what was requested */
1653         bh = sb_bread(sb, n_blocks_count - 1);
1654         if (!bh) {
1655                 ext4_warning(sb, "can't read last block, resize aborted");
1656                 return -ENOSPC;
1657         }
1658         brelse(bh);
1659
1660         /* extend the last group */
1661         if (n_group == o_group)
1662                 add = n_blocks_count - o_blocks_count;
1663         else
1664                 add = EXT4_BLOCKS_PER_GROUP(sb) - (offset + 1);
1665         if (add > 0) {
1666                 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1667                 if (err)
1668                         goto out;
1669         }
1670
1671         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
1672             es->s_log_groups_per_flex)
1673                 flexbg_size = 1 << es->s_log_groups_per_flex;
1674
1675         o_blocks_count = ext4_blocks_count(es);
1676         if (o_blocks_count == n_blocks_count)
1677                 goto out;
1678
1679         flex_gd = alloc_flex_gd(flexbg_size);
1680         if (flex_gd == NULL) {
1681                 err = -ENOMEM;
1682                 goto out;
1683         }
1684
1685         /* Add flex groups. Note that a regular group is a
1686          * flex group with 1 group.
1687          */
1688         while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
1689                                               flexbg_size)) {
1690                 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
1691                         break;
1692                 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
1693                 if (unlikely(err))
1694                         break;
1695         }
1696
1697 out:
1698         if (flex_gd)
1699                 free_flex_gd(flex_gd);
1700
1701         iput(resize_inode);
1702         if (test_opt(sb, DEBUG))
1703                 ext4_msg(sb, KERN_DEBUG, "resized filesystem from %llu "
1704                        "upto %llu blocks", o_blocks_count, n_blocks_count);
1705         return err;
1706 }