xfs: validate acl count
[linux-2.6.git] / fs / ext3 / resize.c
1 /*
2  *  linux/fs/ext3/resize.c
3  *
4  * Support for resizing an ext3 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 EXT3FS_DEBUG
13
14 #include <linux/ext3_jbd.h>
15
16 #include <linux/errno.h>
17 #include <linux/slab.h>
18
19
20 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
21 #define inside(b, first, last)  ((b) >= (first) && (b) < (last))
22
23 static int verify_group_input(struct super_block *sb,
24                               struct ext3_new_group_data *input)
25 {
26         struct ext3_sb_info *sbi = EXT3_SB(sb);
27         struct ext3_super_block *es = sbi->s_es;
28         ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
29         ext3_fsblk_t end = start + input->blocks_count;
30         unsigned group = input->group;
31         ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
32         unsigned overhead = ext3_bg_has_super(sb, group) ?
33                 (1 + ext3_bg_num_gdb(sb, group) +
34                  le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
35         ext3_fsblk_t metaend = start + overhead;
36         struct buffer_head *bh = NULL;
37         ext3_grpblk_t free_blocks_count;
38         int err = -EINVAL;
39
40         input->free_blocks_count = free_blocks_count =
41                 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
42
43         if (test_opt(sb, DEBUG))
44                 printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
45                        "(%d free, %u reserved)\n",
46                        ext3_bg_has_super(sb, input->group) ? "normal" :
47                        "no-super", input->group, input->blocks_count,
48                        free_blocks_count, input->reserved_blocks);
49
50         if (group != sbi->s_groups_count)
51                 ext3_warning(sb, __func__,
52                              "Cannot add at group %u (only %lu groups)",
53                              input->group, sbi->s_groups_count);
54         else if ((start - le32_to_cpu(es->s_first_data_block)) %
55                  EXT3_BLOCKS_PER_GROUP(sb))
56                 ext3_warning(sb, __func__, "Last group not full");
57         else if (input->reserved_blocks > input->blocks_count / 5)
58                 ext3_warning(sb, __func__, "Reserved blocks too high (%u)",
59                              input->reserved_blocks);
60         else if (free_blocks_count < 0)
61                 ext3_warning(sb, __func__, "Bad blocks count %u",
62                              input->blocks_count);
63         else if (!(bh = sb_bread(sb, end - 1)))
64                 ext3_warning(sb, __func__,
65                              "Cannot read last block ("E3FSBLK")",
66                              end - 1);
67         else if (outside(input->block_bitmap, start, end))
68                 ext3_warning(sb, __func__,
69                              "Block bitmap not in group (block %u)",
70                              input->block_bitmap);
71         else if (outside(input->inode_bitmap, start, end))
72                 ext3_warning(sb, __func__,
73                              "Inode bitmap not in group (block %u)",
74                              input->inode_bitmap);
75         else if (outside(input->inode_table, start, end) ||
76                  outside(itend - 1, start, end))
77                 ext3_warning(sb, __func__,
78                              "Inode table not in group (blocks %u-"E3FSBLK")",
79                              input->inode_table, itend - 1);
80         else if (input->inode_bitmap == input->block_bitmap)
81                 ext3_warning(sb, __func__,
82                              "Block bitmap same as inode bitmap (%u)",
83                              input->block_bitmap);
84         else if (inside(input->block_bitmap, input->inode_table, itend))
85                 ext3_warning(sb, __func__,
86                              "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
87                              input->block_bitmap, input->inode_table, itend-1);
88         else if (inside(input->inode_bitmap, input->inode_table, itend))
89                 ext3_warning(sb, __func__,
90                              "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
91                              input->inode_bitmap, input->inode_table, itend-1);
92         else if (inside(input->block_bitmap, start, metaend))
93                 ext3_warning(sb, __func__,
94                              "Block bitmap (%u) in GDT table"
95                              " ("E3FSBLK"-"E3FSBLK")",
96                              input->block_bitmap, start, metaend - 1);
97         else if (inside(input->inode_bitmap, start, metaend))
98                 ext3_warning(sb, __func__,
99                              "Inode bitmap (%u) in GDT table"
100                              " ("E3FSBLK"-"E3FSBLK")",
101                              input->inode_bitmap, start, metaend - 1);
102         else if (inside(input->inode_table, start, metaend) ||
103                  inside(itend - 1, start, metaend))
104                 ext3_warning(sb, __func__,
105                              "Inode table (%u-"E3FSBLK") overlaps"
106                              "GDT table ("E3FSBLK"-"E3FSBLK")",
107                              input->inode_table, itend - 1, start, metaend - 1);
108         else
109                 err = 0;
110         brelse(bh);
111
112         return err;
113 }
114
115 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
116                                   ext3_fsblk_t blk)
117 {
118         struct buffer_head *bh;
119         int err;
120
121         bh = sb_getblk(sb, blk);
122         if (!bh)
123                 return ERR_PTR(-EIO);
124         if ((err = ext3_journal_get_write_access(handle, bh))) {
125                 brelse(bh);
126                 bh = ERR_PTR(err);
127         } else {
128                 lock_buffer(bh);
129                 memset(bh->b_data, 0, sb->s_blocksize);
130                 set_buffer_uptodate(bh);
131                 unlock_buffer(bh);
132         }
133
134         return bh;
135 }
136
137 /*
138  * To avoid calling the atomic setbit hundreds or thousands of times, we only
139  * need to use it within a single byte (to ensure we get endianness right).
140  * We can use memset for the rest of the bitmap as there are no other users.
141  */
142 static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
143 {
144         int i;
145
146         if (start_bit >= end_bit)
147                 return;
148
149         ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
150         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
151                 ext3_set_bit(i, bitmap);
152         if (i < end_bit)
153                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
154 }
155
156 /*
157  * If we have fewer than thresh credits, extend by EXT3_MAX_TRANS_DATA.
158  * If that fails, restart the transaction & regain write access for the
159  * buffer head which is used for block_bitmap modifications.
160  */
161 static int extend_or_restart_transaction(handle_t *handle, int thresh,
162                                          struct buffer_head *bh)
163 {
164         int err;
165
166         if (handle->h_buffer_credits >= thresh)
167                 return 0;
168
169         err = ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA);
170         if (err < 0)
171                 return err;
172         if (err) {
173                 err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA);
174                 if (err)
175                         return err;
176                 err = ext3_journal_get_write_access(handle, bh);
177                 if (err)
178                         return err;
179         }
180
181         return 0;
182 }
183
184 /*
185  * Set up the block and inode bitmaps, and the inode table for the new group.
186  * This doesn't need to be part of the main transaction, since we are only
187  * changing blocks outside the actual filesystem.  We still do journaling to
188  * ensure the recovery is correct in case of a failure just after resize.
189  * If any part of this fails, we simply abort the resize.
190  */
191 static int setup_new_group_blocks(struct super_block *sb,
192                                   struct ext3_new_group_data *input)
193 {
194         struct ext3_sb_info *sbi = EXT3_SB(sb);
195         ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
196         int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
197                 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
198         unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
199         struct buffer_head *bh;
200         handle_t *handle;
201         ext3_fsblk_t block;
202         ext3_grpblk_t bit;
203         int i;
204         int err = 0, err2;
205
206         /* This transaction may be extended/restarted along the way */
207         handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
208
209         if (IS_ERR(handle))
210                 return PTR_ERR(handle);
211
212         mutex_lock(&sbi->s_resize_lock);
213         if (input->group != sbi->s_groups_count) {
214                 err = -EBUSY;
215                 goto exit_journal;
216         }
217
218         if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
219                 err = PTR_ERR(bh);
220                 goto exit_journal;
221         }
222
223         if (ext3_bg_has_super(sb, input->group)) {
224                 ext3_debug("mark backup superblock %#04lx (+0)\n", start);
225                 ext3_set_bit(0, bh->b_data);
226         }
227
228         /* Copy all of the GDT blocks into the backup in this group */
229         for (i = 0, bit = 1, block = start + 1;
230              i < gdblocks; i++, block++, bit++) {
231                 struct buffer_head *gdb;
232
233                 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
234
235                 err = extend_or_restart_transaction(handle, 1, bh);
236                 if (err)
237                         goto exit_bh;
238
239                 gdb = sb_getblk(sb, block);
240                 if (!gdb) {
241                         err = -EIO;
242                         goto exit_bh;
243                 }
244                 if ((err = ext3_journal_get_write_access(handle, gdb))) {
245                         brelse(gdb);
246                         goto exit_bh;
247                 }
248                 lock_buffer(gdb);
249                 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
250                 set_buffer_uptodate(gdb);
251                 unlock_buffer(gdb);
252                 err = ext3_journal_dirty_metadata(handle, gdb);
253                 if (err) {
254                         brelse(gdb);
255                         goto exit_bh;
256                 }
257                 ext3_set_bit(bit, bh->b_data);
258                 brelse(gdb);
259         }
260
261         /* Zero out all of the reserved backup group descriptor table blocks */
262         for (i = 0, bit = gdblocks + 1, block = start + bit;
263              i < reserved_gdb; i++, block++, bit++) {
264                 struct buffer_head *gdb;
265
266                 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
267
268                 err = extend_or_restart_transaction(handle, 1, bh);
269                 if (err)
270                         goto exit_bh;
271
272                 if (IS_ERR(gdb = bclean(handle, sb, block))) {
273                         err = PTR_ERR(gdb);
274                         goto exit_bh;
275                 }
276                 err = ext3_journal_dirty_metadata(handle, gdb);
277                 if (err) {
278                         brelse(gdb);
279                         goto exit_bh;
280                 }
281                 ext3_set_bit(bit, bh->b_data);
282                 brelse(gdb);
283         }
284         ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
285                    input->block_bitmap - start);
286         ext3_set_bit(input->block_bitmap - start, bh->b_data);
287         ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
288                    input->inode_bitmap - start);
289         ext3_set_bit(input->inode_bitmap - start, bh->b_data);
290
291         /* Zero out all of the inode table blocks */
292         for (i = 0, block = input->inode_table, bit = block - start;
293              i < sbi->s_itb_per_group; i++, bit++, block++) {
294                 struct buffer_head *it;
295
296                 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
297
298                 err = extend_or_restart_transaction(handle, 1, bh);
299                 if (err)
300                         goto exit_bh;
301
302                 if (IS_ERR(it = bclean(handle, sb, block))) {
303                         err = PTR_ERR(it);
304                         goto exit_bh;
305                 }
306                 err = ext3_journal_dirty_metadata(handle, it);
307                 if (err) {
308                         brelse(it);
309                         goto exit_bh;
310                 }
311                 brelse(it);
312                 ext3_set_bit(bit, bh->b_data);
313         }
314
315         err = extend_or_restart_transaction(handle, 2, bh);
316         if (err)
317                 goto exit_bh;
318
319         mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
320                         bh->b_data);
321         err = ext3_journal_dirty_metadata(handle, bh);
322         if (err)
323                 goto exit_bh;
324         brelse(bh);
325
326         /* Mark unused entries in inode bitmap used */
327         ext3_debug("clear inode bitmap %#04x (+%ld)\n",
328                    input->inode_bitmap, input->inode_bitmap - start);
329         if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
330                 err = PTR_ERR(bh);
331                 goto exit_journal;
332         }
333
334         mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
335                         bh->b_data);
336         err = ext3_journal_dirty_metadata(handle, bh);
337 exit_bh:
338         brelse(bh);
339
340 exit_journal:
341         mutex_unlock(&sbi->s_resize_lock);
342         if ((err2 = ext3_journal_stop(handle)) && !err)
343                 err = err2;
344
345         return err;
346 }
347
348 /*
349  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
350  * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
351  * calling this for the first time.  In a sparse filesystem it will be the
352  * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
353  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
354  */
355 static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
356                                   unsigned *five, unsigned *seven)
357 {
358         unsigned *min = three;
359         int mult = 3;
360         unsigned ret;
361
362         if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
363                                         EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
364                 ret = *min;
365                 *min += 1;
366                 return ret;
367         }
368
369         if (*five < *min) {
370                 min = five;
371                 mult = 5;
372         }
373         if (*seven < *min) {
374                 min = seven;
375                 mult = 7;
376         }
377
378         ret = *min;
379         *min *= mult;
380
381         return ret;
382 }
383
384 /*
385  * Check that all of the backup GDT blocks are held in the primary GDT block.
386  * It is assumed that they are stored in group order.  Returns the number of
387  * groups in current filesystem that have BACKUPS, or -ve error code.
388  */
389 static int verify_reserved_gdb(struct super_block *sb,
390                                struct buffer_head *primary)
391 {
392         const ext3_fsblk_t blk = primary->b_blocknr;
393         const unsigned long end = EXT3_SB(sb)->s_groups_count;
394         unsigned three = 1;
395         unsigned five = 5;
396         unsigned seven = 7;
397         unsigned grp;
398         __le32 *p = (__le32 *)primary->b_data;
399         int gdbackups = 0;
400
401         while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
402                 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
403                         ext3_warning(sb, __func__,
404                                      "reserved GDT "E3FSBLK
405                                      " missing grp %d ("E3FSBLK")",
406                                      blk, grp,
407                                      grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
408                         return -EINVAL;
409                 }
410                 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
411                         return -EFBIG;
412         }
413
414         return gdbackups;
415 }
416
417 /*
418  * Called when we need to bring a reserved group descriptor table block into
419  * use from the resize inode.  The primary copy of the new GDT block currently
420  * is an indirect block (under the double indirect block in the resize inode).
421  * The new backup GDT blocks will be stored as leaf blocks in this indirect
422  * block, in group order.  Even though we know all the block numbers we need,
423  * we check to ensure that the resize inode has actually reserved these blocks.
424  *
425  * Don't need to update the block bitmaps because the blocks are still in use.
426  *
427  * We get all of the error cases out of the way, so that we are sure to not
428  * fail once we start modifying the data on disk, because JBD has no rollback.
429  */
430 static int add_new_gdb(handle_t *handle, struct inode *inode,
431                        struct ext3_new_group_data *input,
432                        struct buffer_head **primary)
433 {
434         struct super_block *sb = inode->i_sb;
435         struct ext3_super_block *es = EXT3_SB(sb)->s_es;
436         unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
437         ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
438         struct buffer_head **o_group_desc, **n_group_desc;
439         struct buffer_head *dind;
440         int gdbackups;
441         struct ext3_iloc iloc;
442         __le32 *data;
443         int err;
444
445         if (test_opt(sb, DEBUG))
446                 printk(KERN_DEBUG
447                        "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
448                        gdb_num);
449
450         /*
451          * If we are not using the primary superblock/GDT copy don't resize,
452          * because the user tools have no way of handling this.  Probably a
453          * bad time to do it anyways.
454          */
455         if (EXT3_SB(sb)->s_sbh->b_blocknr !=
456             le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
457                 ext3_warning(sb, __func__,
458                         "won't resize using backup superblock at %llu",
459                         (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
460                 return -EPERM;
461         }
462
463         *primary = sb_bread(sb, gdblock);
464         if (!*primary)
465                 return -EIO;
466
467         if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
468                 err = gdbackups;
469                 goto exit_bh;
470         }
471
472         data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
473         dind = sb_bread(sb, le32_to_cpu(*data));
474         if (!dind) {
475                 err = -EIO;
476                 goto exit_bh;
477         }
478
479         data = (__le32 *)dind->b_data;
480         if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
481                 ext3_warning(sb, __func__,
482                              "new group %u GDT block "E3FSBLK" not reserved",
483                              input->group, gdblock);
484                 err = -EINVAL;
485                 goto exit_dind;
486         }
487
488         if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
489                 goto exit_dind;
490
491         if ((err = ext3_journal_get_write_access(handle, *primary)))
492                 goto exit_sbh;
493
494         if ((err = ext3_journal_get_write_access(handle, dind)))
495                 goto exit_primary;
496
497         /* ext3_reserve_inode_write() gets a reference on the iloc */
498         if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
499                 goto exit_dindj;
500
501         n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
502                         GFP_NOFS);
503         if (!n_group_desc) {
504                 err = -ENOMEM;
505                 ext3_warning (sb, __func__,
506                               "not enough memory for %lu groups", gdb_num + 1);
507                 goto exit_inode;
508         }
509
510         /*
511          * Finally, we have all of the possible failures behind us...
512          *
513          * Remove new GDT block from inode double-indirect block and clear out
514          * the new GDT block for use (which also "frees" the backup GDT blocks
515          * from the reserved inode).  We don't need to change the bitmaps for
516          * these blocks, because they are marked as in-use from being in the
517          * reserved inode, and will become GDT blocks (primary and backup).
518          */
519         data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
520         err = ext3_journal_dirty_metadata(handle, dind);
521         if (err)
522                 goto exit_group_desc;
523         brelse(dind);
524         dind = NULL;
525         inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
526         err = ext3_mark_iloc_dirty(handle, inode, &iloc);
527         if (err)
528                 goto exit_group_desc;
529         memset((*primary)->b_data, 0, sb->s_blocksize);
530         err = ext3_journal_dirty_metadata(handle, *primary);
531         if (err)
532                 goto exit_group_desc;
533
534         o_group_desc = EXT3_SB(sb)->s_group_desc;
535         memcpy(n_group_desc, o_group_desc,
536                EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
537         n_group_desc[gdb_num] = *primary;
538         EXT3_SB(sb)->s_group_desc = n_group_desc;
539         EXT3_SB(sb)->s_gdb_count++;
540         kfree(o_group_desc);
541
542         le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
543         err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
544         if (err)
545                 goto exit_inode;
546
547         return 0;
548
549 exit_group_desc:
550         kfree(n_group_desc);
551 exit_inode:
552         //ext3_journal_release_buffer(handle, iloc.bh);
553         brelse(iloc.bh);
554 exit_dindj:
555         //ext3_journal_release_buffer(handle, dind);
556 exit_primary:
557         //ext3_journal_release_buffer(handle, *primary);
558 exit_sbh:
559         //ext3_journal_release_buffer(handle, *primary);
560 exit_dind:
561         brelse(dind);
562 exit_bh:
563         brelse(*primary);
564
565         ext3_debug("leaving with error %d\n", err);
566         return err;
567 }
568
569 /*
570  * Called when we are adding a new group which has a backup copy of each of
571  * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
572  * We need to add these reserved backup GDT blocks to the resize inode, so
573  * that they are kept for future resizing and not allocated to files.
574  *
575  * Each reserved backup GDT block will go into a different indirect block.
576  * The indirect blocks are actually the primary reserved GDT blocks,
577  * so we know in advance what their block numbers are.  We only get the
578  * double-indirect block to verify it is pointing to the primary reserved
579  * GDT blocks so we don't overwrite a data block by accident.  The reserved
580  * backup GDT blocks are stored in their reserved primary GDT block.
581  */
582 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
583                               struct ext3_new_group_data *input)
584 {
585         struct super_block *sb = inode->i_sb;
586         int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
587         struct buffer_head **primary;
588         struct buffer_head *dind;
589         struct ext3_iloc iloc;
590         ext3_fsblk_t blk;
591         __le32 *data, *end;
592         int gdbackups = 0;
593         int res, i;
594         int err;
595
596         primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
597         if (!primary)
598                 return -ENOMEM;
599
600         data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
601         dind = sb_bread(sb, le32_to_cpu(*data));
602         if (!dind) {
603                 err = -EIO;
604                 goto exit_free;
605         }
606
607         blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
608         data = (__le32 *)dind->b_data + (EXT3_SB(sb)->s_gdb_count %
609                                          EXT3_ADDR_PER_BLOCK(sb));
610         end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
611
612         /* Get each reserved primary GDT block and verify it holds backups */
613         for (res = 0; res < reserved_gdb; res++, blk++) {
614                 if (le32_to_cpu(*data) != blk) {
615                         ext3_warning(sb, __func__,
616                                      "reserved block "E3FSBLK
617                                      " not at offset %ld",
618                                      blk,
619                                      (long)(data - (__le32 *)dind->b_data));
620                         err = -EINVAL;
621                         goto exit_bh;
622                 }
623                 primary[res] = sb_bread(sb, blk);
624                 if (!primary[res]) {
625                         err = -EIO;
626                         goto exit_bh;
627                 }
628                 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
629                         brelse(primary[res]);
630                         err = gdbackups;
631                         goto exit_bh;
632                 }
633                 if (++data >= end)
634                         data = (__le32 *)dind->b_data;
635         }
636
637         for (i = 0; i < reserved_gdb; i++) {
638                 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
639                         /*
640                         int j;
641                         for (j = 0; j < i; j++)
642                                 ext3_journal_release_buffer(handle, primary[j]);
643                          */
644                         goto exit_bh;
645                 }
646         }
647
648         if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
649                 goto exit_bh;
650
651         /*
652          * Finally we can add each of the reserved backup GDT blocks from
653          * the new group to its reserved primary GDT block.
654          */
655         blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
656         for (i = 0; i < reserved_gdb; i++) {
657                 int err2;
658                 data = (__le32 *)primary[i]->b_data;
659                 /* printk("reserving backup %lu[%u] = %lu\n",
660                        primary[i]->b_blocknr, gdbackups,
661                        blk + primary[i]->b_blocknr); */
662                 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
663                 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
664                 if (!err)
665                         err = err2;
666         }
667         inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
668         ext3_mark_iloc_dirty(handle, inode, &iloc);
669
670 exit_bh:
671         while (--res >= 0)
672                 brelse(primary[res]);
673         brelse(dind);
674
675 exit_free:
676         kfree(primary);
677
678         return err;
679 }
680
681 /*
682  * Update the backup copies of the ext3 metadata.  These don't need to be part
683  * of the main resize transaction, because e2fsck will re-write them if there
684  * is a problem (basically only OOM will cause a problem).  However, we
685  * _should_ update the backups if possible, in case the primary gets trashed
686  * for some reason and we need to run e2fsck from a backup superblock.  The
687  * important part is that the new block and inode counts are in the backup
688  * superblocks, and the location of the new group metadata in the GDT backups.
689  *
690  * We do not need take the s_resize_lock for this, because these
691  * blocks are not otherwise touched by the filesystem code when it is
692  * mounted.  We don't need to worry about last changing from
693  * sbi->s_groups_count, because the worst that can happen is that we
694  * do not copy the full number of backups at this time.  The resize
695  * which changed s_groups_count will backup again.
696  */
697 static void update_backups(struct super_block *sb,
698                            int blk_off, char *data, int size)
699 {
700         struct ext3_sb_info *sbi = EXT3_SB(sb);
701         const unsigned long last = sbi->s_groups_count;
702         const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
703         unsigned three = 1;
704         unsigned five = 5;
705         unsigned seven = 7;
706         unsigned group;
707         int rest = sb->s_blocksize - size;
708         handle_t *handle;
709         int err = 0, err2;
710
711         handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
712         if (IS_ERR(handle)) {
713                 group = 1;
714                 err = PTR_ERR(handle);
715                 goto exit_err;
716         }
717
718         while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
719                 struct buffer_head *bh;
720
721                 /* Out of journal space, and can't get more - abort - so sad */
722                 if (handle->h_buffer_credits == 0 &&
723                     ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
724                     (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
725                         break;
726
727                 bh = sb_getblk(sb, group * bpg + blk_off);
728                 if (!bh) {
729                         err = -EIO;
730                         break;
731                 }
732                 ext3_debug("update metadata backup %#04lx\n",
733                           (unsigned long)bh->b_blocknr);
734                 if ((err = ext3_journal_get_write_access(handle, bh))) {
735                         brelse(bh);
736                         break;
737                 }
738                 lock_buffer(bh);
739                 memcpy(bh->b_data, data, size);
740                 if (rest)
741                         memset(bh->b_data + size, 0, rest);
742                 set_buffer_uptodate(bh);
743                 unlock_buffer(bh);
744                 err = ext3_journal_dirty_metadata(handle, bh);
745                 brelse(bh);
746                 if (err)
747                         break;
748         }
749         if ((err2 = ext3_journal_stop(handle)) && !err)
750                 err = err2;
751
752         /*
753          * Ugh! Need to have e2fsck write the backup copies.  It is too
754          * late to revert the resize, we shouldn't fail just because of
755          * the backup copies (they are only needed in case of corruption).
756          *
757          * However, if we got here we have a journal problem too, so we
758          * can't really start a transaction to mark the superblock.
759          * Chicken out and just set the flag on the hope it will be written
760          * to disk, and if not - we will simply wait until next fsck.
761          */
762 exit_err:
763         if (err) {
764                 ext3_warning(sb, __func__,
765                              "can't update backup for group %d (err %d), "
766                              "forcing fsck on next reboot", group, err);
767                 sbi->s_mount_state &= ~EXT3_VALID_FS;
768                 sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS);
769                 mark_buffer_dirty(sbi->s_sbh);
770         }
771 }
772
773 /* Add group descriptor data to an existing or new group descriptor block.
774  * Ensure we handle all possible error conditions _before_ we start modifying
775  * the filesystem, because we cannot abort the transaction and not have it
776  * write the data to disk.
777  *
778  * If we are on a GDT block boundary, we need to get the reserved GDT block.
779  * Otherwise, we may need to add backup GDT blocks for a sparse group.
780  *
781  * We only need to hold the superblock lock while we are actually adding
782  * in the new group's counts to the superblock.  Prior to that we have
783  * not really "added" the group at all.  We re-check that we are still
784  * adding in the last group in case things have changed since verifying.
785  */
786 int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
787 {
788         struct ext3_sb_info *sbi = EXT3_SB(sb);
789         struct ext3_super_block *es = sbi->s_es;
790         int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
791                 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
792         struct buffer_head *primary = NULL;
793         struct ext3_group_desc *gdp;
794         struct inode *inode = NULL;
795         handle_t *handle;
796         int gdb_off, gdb_num;
797         int err, err2;
798
799         gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
800         gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
801
802         if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
803                                         EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
804                 ext3_warning(sb, __func__,
805                              "Can't resize non-sparse filesystem further");
806                 return -EPERM;
807         }
808
809         if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
810             le32_to_cpu(es->s_blocks_count)) {
811                 ext3_warning(sb, __func__, "blocks_count overflow\n");
812                 return -EINVAL;
813         }
814
815         if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
816             le32_to_cpu(es->s_inodes_count)) {
817                 ext3_warning(sb, __func__, "inodes_count overflow\n");
818                 return -EINVAL;
819         }
820
821         if (reserved_gdb || gdb_off == 0) {
822                 if (!EXT3_HAS_COMPAT_FEATURE(sb,
823                                              EXT3_FEATURE_COMPAT_RESIZE_INODE)
824                     || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
825                         ext3_warning(sb, __func__,
826                                      "No reserved GDT blocks, can't resize");
827                         return -EPERM;
828                 }
829                 inode = ext3_iget(sb, EXT3_RESIZE_INO);
830                 if (IS_ERR(inode)) {
831                         ext3_warning(sb, __func__,
832                                      "Error opening resize inode");
833                         return PTR_ERR(inode);
834                 }
835         }
836
837         if ((err = verify_group_input(sb, input)))
838                 goto exit_put;
839
840         if ((err = setup_new_group_blocks(sb, input)))
841                 goto exit_put;
842
843         /*
844          * We will always be modifying at least the superblock and a GDT
845          * block.  If we are adding a group past the last current GDT block,
846          * we will also modify the inode and the dindirect block.  If we
847          * are adding a group with superblock/GDT backups  we will also
848          * modify each of the reserved GDT dindirect blocks.
849          */
850         handle = ext3_journal_start_sb(sb,
851                                        ext3_bg_has_super(sb, input->group) ?
852                                        3 + reserved_gdb : 4);
853         if (IS_ERR(handle)) {
854                 err = PTR_ERR(handle);
855                 goto exit_put;
856         }
857
858         mutex_lock(&sbi->s_resize_lock);
859         if (input->group != sbi->s_groups_count) {
860                 ext3_warning(sb, __func__,
861                              "multiple resizers run on filesystem!");
862                 err = -EBUSY;
863                 goto exit_journal;
864         }
865
866         if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
867                 goto exit_journal;
868
869         /*
870          * We will only either add reserved group blocks to a backup group
871          * or remove reserved blocks for the first group in a new group block.
872          * Doing both would be mean more complex code, and sane people don't
873          * use non-sparse filesystems anymore.  This is already checked above.
874          */
875         if (gdb_off) {
876                 primary = sbi->s_group_desc[gdb_num];
877                 if ((err = ext3_journal_get_write_access(handle, primary)))
878                         goto exit_journal;
879
880                 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
881                     (err = reserve_backup_gdb(handle, inode, input)))
882                         goto exit_journal;
883         } else if ((err = add_new_gdb(handle, inode, input, &primary)))
884                 goto exit_journal;
885
886         /*
887          * OK, now we've set up the new group.  Time to make it active.
888          *
889          * We do not lock all allocations via s_resize_lock
890          * so we have to be safe wrt. concurrent accesses the group
891          * data.  So we need to be careful to set all of the relevant
892          * group descriptor data etc. *before* we enable the group.
893          *
894          * The key field here is sbi->s_groups_count: as long as
895          * that retains its old value, nobody is going to access the new
896          * group.
897          *
898          * So first we update all the descriptor metadata for the new
899          * group; then we update the total disk blocks count; then we
900          * update the groups count to enable the group; then finally we
901          * update the free space counts so that the system can start
902          * using the new disk blocks.
903          */
904
905         /* Update group descriptor block for new group */
906         gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
907
908         gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
909         gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
910         gdp->bg_inode_table = cpu_to_le32(input->inode_table);
911         gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
912         gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
913
914         /*
915          * Make the new blocks and inodes valid next.  We do this before
916          * increasing the group count so that once the group is enabled,
917          * all of its blocks and inodes are already valid.
918          *
919          * We always allocate group-by-group, then block-by-block or
920          * inode-by-inode within a group, so enabling these
921          * blocks/inodes before the group is live won't actually let us
922          * allocate the new space yet.
923          */
924         le32_add_cpu(&es->s_blocks_count, input->blocks_count);
925         le32_add_cpu(&es->s_inodes_count, EXT3_INODES_PER_GROUP(sb));
926
927         /*
928          * We need to protect s_groups_count against other CPUs seeing
929          * inconsistent state in the superblock.
930          *
931          * The precise rules we use are:
932          *
933          * * Writers of s_groups_count *must* hold s_resize_lock
934          * AND
935          * * Writers must perform a smp_wmb() after updating all dependent
936          *   data and before modifying the groups count
937          *
938          * * Readers must hold s_resize_lock over the access
939          * OR
940          * * Readers must perform an smp_rmb() after reading the groups count
941          *   and before reading any dependent data.
942          *
943          * NB. These rules can be relaxed when checking the group count
944          * while freeing data, as we can only allocate from a block
945          * group after serialising against the group count, and we can
946          * only then free after serialising in turn against that
947          * allocation.
948          */
949         smp_wmb();
950
951         /* Update the global fs size fields */
952         sbi->s_groups_count++;
953
954         err = ext3_journal_dirty_metadata(handle, primary);
955         if (err)
956                 goto exit_journal;
957
958         /* Update the reserved block counts only once the new group is
959          * active. */
960         le32_add_cpu(&es->s_r_blocks_count, input->reserved_blocks);
961
962         /* Update the free space counts */
963         percpu_counter_add(&sbi->s_freeblocks_counter,
964                            input->free_blocks_count);
965         percpu_counter_add(&sbi->s_freeinodes_counter,
966                            EXT3_INODES_PER_GROUP(sb));
967
968         err = ext3_journal_dirty_metadata(handle, sbi->s_sbh);
969
970 exit_journal:
971         mutex_unlock(&sbi->s_resize_lock);
972         if ((err2 = ext3_journal_stop(handle)) && !err)
973                 err = err2;
974         if (!err) {
975                 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
976                                sizeof(struct ext3_super_block));
977                 update_backups(sb, primary->b_blocknr, primary->b_data,
978                                primary->b_size);
979         }
980 exit_put:
981         iput(inode);
982         return err;
983 } /* ext3_group_add */
984
985 /* Extend the filesystem to the new number of blocks specified.  This entry
986  * point is only used to extend the current filesystem to the end of the last
987  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
988  * for emergencies (because it has no dependencies on reserved blocks).
989  *
990  * If we _really_ wanted, we could use default values to call ext3_group_add()
991  * allow the "remount" trick to work for arbitrary resizing, assuming enough
992  * GDT blocks are reserved to grow to the desired size.
993  */
994 int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
995                       ext3_fsblk_t n_blocks_count)
996 {
997         ext3_fsblk_t o_blocks_count;
998         ext3_grpblk_t last;
999         ext3_grpblk_t add;
1000         struct buffer_head * bh;
1001         handle_t *handle;
1002         int err;
1003         unsigned long freed_blocks;
1004
1005         /* We don't need to worry about locking wrt other resizers just
1006          * yet: we're going to revalidate es->s_blocks_count after
1007          * taking the s_resize_lock below. */
1008         o_blocks_count = le32_to_cpu(es->s_blocks_count);
1009
1010         if (test_opt(sb, DEBUG))
1011                 printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK
1012                        " up to "E3FSBLK" blocks\n",
1013                        o_blocks_count, n_blocks_count);
1014
1015         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1016                 return 0;
1017
1018         if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1019                 printk(KERN_ERR "EXT3-fs: filesystem on %s:"
1020                         " too large to resize to "E3FSBLK" blocks safely\n",
1021                         sb->s_id, n_blocks_count);
1022                 if (sizeof(sector_t) < 8)
1023                         ext3_warning(sb, __func__,
1024                         "CONFIG_LBDAF not enabled\n");
1025                 return -EINVAL;
1026         }
1027
1028         if (n_blocks_count < o_blocks_count) {
1029                 ext3_warning(sb, __func__,
1030                              "can't shrink FS - resize aborted");
1031                 return -EBUSY;
1032         }
1033
1034         /* Handle the remaining blocks in the last group only. */
1035         last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
1036                 EXT3_BLOCKS_PER_GROUP(sb);
1037
1038         if (last == 0) {
1039                 ext3_warning(sb, __func__,
1040                              "need to use ext2online to resize further");
1041                 return -EPERM;
1042         }
1043
1044         add = EXT3_BLOCKS_PER_GROUP(sb) - last;
1045
1046         if (o_blocks_count + add < o_blocks_count) {
1047                 ext3_warning(sb, __func__, "blocks_count overflow");
1048                 return -EINVAL;
1049         }
1050
1051         if (o_blocks_count + add > n_blocks_count)
1052                 add = n_blocks_count - o_blocks_count;
1053
1054         if (o_blocks_count + add < n_blocks_count)
1055                 ext3_warning(sb, __func__,
1056                              "will only finish group ("E3FSBLK
1057                              " blocks, %u new)",
1058                              o_blocks_count + add, add);
1059
1060         /* See if the device is actually as big as what was requested */
1061         bh = sb_bread(sb, o_blocks_count + add -1);
1062         if (!bh) {
1063                 ext3_warning(sb, __func__,
1064                              "can't read last block, resize aborted");
1065                 return -ENOSPC;
1066         }
1067         brelse(bh);
1068
1069         /* We will update the superblock, one block bitmap, and
1070          * one group descriptor via ext3_free_blocks().
1071          */
1072         handle = ext3_journal_start_sb(sb, 3);
1073         if (IS_ERR(handle)) {
1074                 err = PTR_ERR(handle);
1075                 ext3_warning(sb, __func__, "error %d on journal start",err);
1076                 goto exit_put;
1077         }
1078
1079         mutex_lock(&EXT3_SB(sb)->s_resize_lock);
1080         if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
1081                 ext3_warning(sb, __func__,
1082                              "multiple resizers run on filesystem!");
1083                 mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
1084                 ext3_journal_stop(handle);
1085                 err = -EBUSY;
1086                 goto exit_put;
1087         }
1088
1089         if ((err = ext3_journal_get_write_access(handle,
1090                                                  EXT3_SB(sb)->s_sbh))) {
1091                 ext3_warning(sb, __func__,
1092                              "error %d on journal write access", err);
1093                 mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
1094                 ext3_journal_stop(handle);
1095                 goto exit_put;
1096         }
1097         es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
1098         err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
1099         mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
1100         if (err) {
1101                 ext3_warning(sb, __func__,
1102                              "error %d on journal dirty metadata", err);
1103                 ext3_journal_stop(handle);
1104                 goto exit_put;
1105         }
1106         ext3_debug("freeing blocks "E3FSBLK" through "E3FSBLK"\n",
1107                    o_blocks_count, o_blocks_count + add);
1108         ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1109         ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n",
1110                    o_blocks_count, o_blocks_count + add);
1111         if ((err = ext3_journal_stop(handle)))
1112                 goto exit_put;
1113         if (test_opt(sb, DEBUG))
1114                 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
1115                        le32_to_cpu(es->s_blocks_count));
1116         update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
1117                        sizeof(struct ext3_super_block));
1118 exit_put:
1119         return err;
1120 } /* ext3_group_extend */