ia64/linux-2.6.18-xen.hg

view fs/ext3/resize.c @ 524:7f8b544237bf

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This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
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 */
12 #define EXT3FS_DEBUG
14 #include <linux/sched.h>
15 #include <linux/smp_lock.h>
16 #include <linux/ext3_jbd.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
22 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
23 #define inside(b, first, last) ((b) >= (first) && (b) < (last))
25 static int verify_group_input(struct super_block *sb,
26 struct ext3_new_group_data *input)
27 {
28 struct ext3_sb_info *sbi = EXT3_SB(sb);
29 struct ext3_super_block *es = sbi->s_es;
30 ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
31 ext3_fsblk_t end = start + input->blocks_count;
32 unsigned group = input->group;
33 ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
34 unsigned overhead = ext3_bg_has_super(sb, group) ?
35 (1 + ext3_bg_num_gdb(sb, group) +
36 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
37 ext3_fsblk_t metaend = start + overhead;
38 struct buffer_head *bh = NULL;
39 ext3_grpblk_t free_blocks_count;
40 int err = -EINVAL;
42 input->free_blocks_count = free_blocks_count =
43 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
45 if (test_opt(sb, DEBUG))
46 printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
47 "(%d free, %u reserved)\n",
48 ext3_bg_has_super(sb, input->group) ? "normal" :
49 "no-super", input->group, input->blocks_count,
50 free_blocks_count, input->reserved_blocks);
52 if (group != sbi->s_groups_count)
53 ext3_warning(sb, __FUNCTION__,
54 "Cannot add at group %u (only %lu groups)",
55 input->group, sbi->s_groups_count);
56 else if ((start - le32_to_cpu(es->s_first_data_block)) %
57 EXT3_BLOCKS_PER_GROUP(sb))
58 ext3_warning(sb, __FUNCTION__, "Last group not full");
59 else if (input->reserved_blocks > input->blocks_count / 5)
60 ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
61 input->reserved_blocks);
62 else if (free_blocks_count < 0)
63 ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
64 input->blocks_count);
65 else if (!(bh = sb_bread(sb, end - 1)))
66 ext3_warning(sb, __FUNCTION__,
67 "Cannot read last block ("E3FSBLK")",
68 end - 1);
69 else if (outside(input->block_bitmap, start, end))
70 ext3_warning(sb, __FUNCTION__,
71 "Block bitmap not in group (block %u)",
72 input->block_bitmap);
73 else if (outside(input->inode_bitmap, start, end))
74 ext3_warning(sb, __FUNCTION__,
75 "Inode bitmap not in group (block %u)",
76 input->inode_bitmap);
77 else if (outside(input->inode_table, start, end) ||
78 outside(itend - 1, start, end))
79 ext3_warning(sb, __FUNCTION__,
80 "Inode table not in group (blocks %u-"E3FSBLK")",
81 input->inode_table, itend - 1);
82 else if (input->inode_bitmap == input->block_bitmap)
83 ext3_warning(sb, __FUNCTION__,
84 "Block bitmap same as inode bitmap (%u)",
85 input->block_bitmap);
86 else if (inside(input->block_bitmap, input->inode_table, itend))
87 ext3_warning(sb, __FUNCTION__,
88 "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
89 input->block_bitmap, input->inode_table, itend-1);
90 else if (inside(input->inode_bitmap, input->inode_table, itend))
91 ext3_warning(sb, __FUNCTION__,
92 "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
93 input->inode_bitmap, input->inode_table, itend-1);
94 else if (inside(input->block_bitmap, start, metaend))
95 ext3_warning(sb, __FUNCTION__,
96 "Block bitmap (%u) in GDT table"
97 " ("E3FSBLK"-"E3FSBLK")",
98 input->block_bitmap, start, metaend - 1);
99 else if (inside(input->inode_bitmap, start, metaend))
100 ext3_warning(sb, __FUNCTION__,
101 "Inode bitmap (%u) in GDT table"
102 " ("E3FSBLK"-"E3FSBLK")",
103 input->inode_bitmap, start, metaend - 1);
104 else if (inside(input->inode_table, start, metaend) ||
105 inside(itend - 1, start, metaend))
106 ext3_warning(sb, __FUNCTION__,
107 "Inode table (%u-"E3FSBLK") overlaps"
108 "GDT table ("E3FSBLK"-"E3FSBLK")",
109 input->inode_table, itend - 1, start, metaend - 1);
110 else
111 err = 0;
112 brelse(bh);
114 return err;
115 }
117 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
118 ext3_fsblk_t blk)
119 {
120 struct buffer_head *bh;
121 int err;
123 bh = sb_getblk(sb, blk);
124 if (!bh)
125 return ERR_PTR(-EIO);
126 if ((err = ext3_journal_get_write_access(handle, bh))) {
127 brelse(bh);
128 bh = ERR_PTR(err);
129 } else {
130 lock_buffer(bh);
131 memset(bh->b_data, 0, sb->s_blocksize);
132 set_buffer_uptodate(bh);
133 unlock_buffer(bh);
134 }
136 return bh;
137 }
139 /*
140 * To avoid calling the atomic setbit hundreds or thousands of times, we only
141 * need to use it within a single byte (to ensure we get endianness right).
142 * We can use memset for the rest of the bitmap as there are no other users.
143 */
144 static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
145 {
146 int i;
148 if (start_bit >= end_bit)
149 return;
151 ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
152 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
153 ext3_set_bit(i, bitmap);
154 if (i < end_bit)
155 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
156 }
158 /*
159 * Set up the block and inode bitmaps, and the inode table for the new group.
160 * This doesn't need to be part of the main transaction, since we are only
161 * changing blocks outside the actual filesystem. We still do journaling to
162 * ensure the recovery is correct in case of a failure just after resize.
163 * If any part of this fails, we simply abort the resize.
164 */
165 static int setup_new_group_blocks(struct super_block *sb,
166 struct ext3_new_group_data *input)
167 {
168 struct ext3_sb_info *sbi = EXT3_SB(sb);
169 ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
170 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
171 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
172 unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
173 struct buffer_head *bh;
174 handle_t *handle;
175 ext3_fsblk_t block;
176 ext3_grpblk_t bit;
177 int i;
178 int err = 0, err2;
180 handle = ext3_journal_start_sb(sb, reserved_gdb + gdblocks +
181 2 + sbi->s_itb_per_group);
182 if (IS_ERR(handle))
183 return PTR_ERR(handle);
185 lock_super(sb);
186 if (input->group != sbi->s_groups_count) {
187 err = -EBUSY;
188 goto exit_journal;
189 }
191 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
192 err = PTR_ERR(bh);
193 goto exit_journal;
194 }
196 if (ext3_bg_has_super(sb, input->group)) {
197 ext3_debug("mark backup superblock %#04lx (+0)\n", start);
198 ext3_set_bit(0, bh->b_data);
199 }
201 /* Copy all of the GDT blocks into the backup in this group */
202 for (i = 0, bit = 1, block = start + 1;
203 i < gdblocks; i++, block++, bit++) {
204 struct buffer_head *gdb;
206 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
208 gdb = sb_getblk(sb, block);
209 if (!gdb) {
210 err = -EIO;
211 goto exit_bh;
212 }
213 if ((err = ext3_journal_get_write_access(handle, gdb))) {
214 brelse(gdb);
215 goto exit_bh;
216 }
217 lock_buffer(bh);
218 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size);
219 set_buffer_uptodate(gdb);
220 unlock_buffer(bh);
221 ext3_journal_dirty_metadata(handle, gdb);
222 ext3_set_bit(bit, bh->b_data);
223 brelse(gdb);
224 }
226 /* Zero out all of the reserved backup group descriptor table blocks */
227 for (i = 0, bit = gdblocks + 1, block = start + bit;
228 i < reserved_gdb; i++, block++, bit++) {
229 struct buffer_head *gdb;
231 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
233 if (IS_ERR(gdb = bclean(handle, sb, block))) {
234 err = PTR_ERR(bh);
235 goto exit_bh;
236 }
237 ext3_journal_dirty_metadata(handle, gdb);
238 ext3_set_bit(bit, bh->b_data);
239 brelse(gdb);
240 }
241 ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
242 input->block_bitmap - start);
243 ext3_set_bit(input->block_bitmap - start, bh->b_data);
244 ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
245 input->inode_bitmap - start);
246 ext3_set_bit(input->inode_bitmap - start, bh->b_data);
248 /* Zero out all of the inode table blocks */
249 for (i = 0, block = input->inode_table, bit = block - start;
250 i < sbi->s_itb_per_group; i++, bit++, block++) {
251 struct buffer_head *it;
253 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
254 if (IS_ERR(it = bclean(handle, sb, block))) {
255 err = PTR_ERR(it);
256 goto exit_bh;
257 }
258 ext3_journal_dirty_metadata(handle, it);
259 brelse(it);
260 ext3_set_bit(bit, bh->b_data);
261 }
262 mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
263 bh->b_data);
264 ext3_journal_dirty_metadata(handle, bh);
265 brelse(bh);
267 /* Mark unused entries in inode bitmap used */
268 ext3_debug("clear inode bitmap %#04x (+%ld)\n",
269 input->inode_bitmap, input->inode_bitmap - start);
270 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
271 err = PTR_ERR(bh);
272 goto exit_journal;
273 }
275 mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
276 bh->b_data);
277 ext3_journal_dirty_metadata(handle, bh);
278 exit_bh:
279 brelse(bh);
281 exit_journal:
282 unlock_super(sb);
283 if ((err2 = ext3_journal_stop(handle)) && !err)
284 err = err2;
286 return err;
287 }
289 /*
290 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
291 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
292 * calling this for the first time. In a sparse filesystem it will be the
293 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
294 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
295 */
296 static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
297 unsigned *five, unsigned *seven)
298 {
299 unsigned *min = three;
300 int mult = 3;
301 unsigned ret;
303 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
304 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
305 ret = *min;
306 *min += 1;
307 return ret;
308 }
310 if (*five < *min) {
311 min = five;
312 mult = 5;
313 }
314 if (*seven < *min) {
315 min = seven;
316 mult = 7;
317 }
319 ret = *min;
320 *min *= mult;
322 return ret;
323 }
325 /*
326 * Check that all of the backup GDT blocks are held in the primary GDT block.
327 * It is assumed that they are stored in group order. Returns the number of
328 * groups in current filesystem that have BACKUPS, or -ve error code.
329 */
330 static int verify_reserved_gdb(struct super_block *sb,
331 struct buffer_head *primary)
332 {
333 const ext3_fsblk_t blk = primary->b_blocknr;
334 const unsigned long end = EXT3_SB(sb)->s_groups_count;
335 unsigned three = 1;
336 unsigned five = 5;
337 unsigned seven = 7;
338 unsigned grp;
339 __u32 *p = (__u32 *)primary->b_data;
340 int gdbackups = 0;
342 while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
343 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
344 ext3_warning(sb, __FUNCTION__,
345 "reserved GDT "E3FSBLK
346 " missing grp %d ("E3FSBLK")",
347 blk, grp,
348 grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
349 return -EINVAL;
350 }
351 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
352 return -EFBIG;
353 }
355 return gdbackups;
356 }
358 /*
359 * Called when we need to bring a reserved group descriptor table block into
360 * use from the resize inode. The primary copy of the new GDT block currently
361 * is an indirect block (under the double indirect block in the resize inode).
362 * The new backup GDT blocks will be stored as leaf blocks in this indirect
363 * block, in group order. Even though we know all the block numbers we need,
364 * we check to ensure that the resize inode has actually reserved these blocks.
365 *
366 * Don't need to update the block bitmaps because the blocks are still in use.
367 *
368 * We get all of the error cases out of the way, so that we are sure to not
369 * fail once we start modifying the data on disk, because JBD has no rollback.
370 */
371 static int add_new_gdb(handle_t *handle, struct inode *inode,
372 struct ext3_new_group_data *input,
373 struct buffer_head **primary)
374 {
375 struct super_block *sb = inode->i_sb;
376 struct ext3_super_block *es = EXT3_SB(sb)->s_es;
377 unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
378 ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
379 struct buffer_head **o_group_desc, **n_group_desc;
380 struct buffer_head *dind;
381 int gdbackups;
382 struct ext3_iloc iloc;
383 __u32 *data;
384 int err;
386 if (test_opt(sb, DEBUG))
387 printk(KERN_DEBUG
388 "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
389 gdb_num);
391 /*
392 * If we are not using the primary superblock/GDT copy don't resize,
393 * because the user tools have no way of handling this. Probably a
394 * bad time to do it anyways.
395 */
396 if (EXT3_SB(sb)->s_sbh->b_blocknr !=
397 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
398 ext3_warning(sb, __FUNCTION__,
399 "won't resize using backup superblock at %llu",
400 (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
401 return -EPERM;
402 }
404 *primary = sb_bread(sb, gdblock);
405 if (!*primary)
406 return -EIO;
408 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
409 err = gdbackups;
410 goto exit_bh;
411 }
413 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
414 dind = sb_bread(sb, le32_to_cpu(*data));
415 if (!dind) {
416 err = -EIO;
417 goto exit_bh;
418 }
420 data = (__u32 *)dind->b_data;
421 if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
422 ext3_warning(sb, __FUNCTION__,
423 "new group %u GDT block "E3FSBLK" not reserved",
424 input->group, gdblock);
425 err = -EINVAL;
426 goto exit_dind;
427 }
429 if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
430 goto exit_dind;
432 if ((err = ext3_journal_get_write_access(handle, *primary)))
433 goto exit_sbh;
435 if ((err = ext3_journal_get_write_access(handle, dind)))
436 goto exit_primary;
438 /* ext3_reserve_inode_write() gets a reference on the iloc */
439 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
440 goto exit_dindj;
442 n_group_desc = (struct buffer_head **)kmalloc((gdb_num + 1) *
443 sizeof(struct buffer_head *), GFP_KERNEL);
444 if (!n_group_desc) {
445 err = -ENOMEM;
446 ext3_warning (sb, __FUNCTION__,
447 "not enough memory for %lu groups", gdb_num + 1);
448 goto exit_inode;
449 }
451 /*
452 * Finally, we have all of the possible failures behind us...
453 *
454 * Remove new GDT block from inode double-indirect block and clear out
455 * the new GDT block for use (which also "frees" the backup GDT blocks
456 * from the reserved inode). We don't need to change the bitmaps for
457 * these blocks, because they are marked as in-use from being in the
458 * reserved inode, and will become GDT blocks (primary and backup).
459 */
460 data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
461 ext3_journal_dirty_metadata(handle, dind);
462 brelse(dind);
463 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
464 ext3_mark_iloc_dirty(handle, inode, &iloc);
465 memset((*primary)->b_data, 0, sb->s_blocksize);
466 ext3_journal_dirty_metadata(handle, *primary);
468 o_group_desc = EXT3_SB(sb)->s_group_desc;
469 memcpy(n_group_desc, o_group_desc,
470 EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
471 n_group_desc[gdb_num] = *primary;
472 EXT3_SB(sb)->s_group_desc = n_group_desc;
473 EXT3_SB(sb)->s_gdb_count++;
474 kfree(o_group_desc);
476 es->s_reserved_gdt_blocks =
477 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
478 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
480 return 0;
482 exit_inode:
483 //ext3_journal_release_buffer(handle, iloc.bh);
484 brelse(iloc.bh);
485 exit_dindj:
486 //ext3_journal_release_buffer(handle, dind);
487 exit_primary:
488 //ext3_journal_release_buffer(handle, *primary);
489 exit_sbh:
490 //ext3_journal_release_buffer(handle, *primary);
491 exit_dind:
492 brelse(dind);
493 exit_bh:
494 brelse(*primary);
496 ext3_debug("leaving with error %d\n", err);
497 return err;
498 }
500 /*
501 * Called when we are adding a new group which has a backup copy of each of
502 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
503 * We need to add these reserved backup GDT blocks to the resize inode, so
504 * that they are kept for future resizing and not allocated to files.
505 *
506 * Each reserved backup GDT block will go into a different indirect block.
507 * The indirect blocks are actually the primary reserved GDT blocks,
508 * so we know in advance what their block numbers are. We only get the
509 * double-indirect block to verify it is pointing to the primary reserved
510 * GDT blocks so we don't overwrite a data block by accident. The reserved
511 * backup GDT blocks are stored in their reserved primary GDT block.
512 */
513 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
514 struct ext3_new_group_data *input)
515 {
516 struct super_block *sb = inode->i_sb;
517 int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
518 struct buffer_head **primary;
519 struct buffer_head *dind;
520 struct ext3_iloc iloc;
521 ext3_fsblk_t blk;
522 __u32 *data, *end;
523 int gdbackups = 0;
524 int res, i;
525 int err;
527 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
528 if (!primary)
529 return -ENOMEM;
531 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
532 dind = sb_bread(sb, le32_to_cpu(*data));
533 if (!dind) {
534 err = -EIO;
535 goto exit_free;
536 }
538 blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
539 data = (__u32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
540 end = (__u32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
542 /* Get each reserved primary GDT block and verify it holds backups */
543 for (res = 0; res < reserved_gdb; res++, blk++) {
544 if (le32_to_cpu(*data) != blk) {
545 ext3_warning(sb, __FUNCTION__,
546 "reserved block "E3FSBLK
547 " not at offset %ld",
548 blk, (long)(data - (__u32 *)dind->b_data));
549 err = -EINVAL;
550 goto exit_bh;
551 }
552 primary[res] = sb_bread(sb, blk);
553 if (!primary[res]) {
554 err = -EIO;
555 goto exit_bh;
556 }
557 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
558 brelse(primary[res]);
559 err = gdbackups;
560 goto exit_bh;
561 }
562 if (++data >= end)
563 data = (__u32 *)dind->b_data;
564 }
566 for (i = 0; i < reserved_gdb; i++) {
567 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
568 /*
569 int j;
570 for (j = 0; j < i; j++)
571 ext3_journal_release_buffer(handle, primary[j]);
572 */
573 goto exit_bh;
574 }
575 }
577 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
578 goto exit_bh;
580 /*
581 * Finally we can add each of the reserved backup GDT blocks from
582 * the new group to its reserved primary GDT block.
583 */
584 blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
585 for (i = 0; i < reserved_gdb; i++) {
586 int err2;
587 data = (__u32 *)primary[i]->b_data;
588 /* printk("reserving backup %lu[%u] = %lu\n",
589 primary[i]->b_blocknr, gdbackups,
590 blk + primary[i]->b_blocknr); */
591 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
592 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
593 if (!err)
594 err = err2;
595 }
596 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
597 ext3_mark_iloc_dirty(handle, inode, &iloc);
599 exit_bh:
600 while (--res >= 0)
601 brelse(primary[res]);
602 brelse(dind);
604 exit_free:
605 kfree(primary);
607 return err;
608 }
610 /*
611 * Update the backup copies of the ext3 metadata. These don't need to be part
612 * of the main resize transaction, because e2fsck will re-write them if there
613 * is a problem (basically only OOM will cause a problem). However, we
614 * _should_ update the backups if possible, in case the primary gets trashed
615 * for some reason and we need to run e2fsck from a backup superblock. The
616 * important part is that the new block and inode counts are in the backup
617 * superblocks, and the location of the new group metadata in the GDT backups.
618 *
619 * We do not need lock_super() for this, because these blocks are not
620 * otherwise touched by the filesystem code when it is mounted. We don't
621 * need to worry about last changing from sbi->s_groups_count, because the
622 * worst that can happen is that we do not copy the full number of backups
623 * at this time. The resize which changed s_groups_count will backup again.
624 */
625 static void update_backups(struct super_block *sb,
626 int blk_off, char *data, int size)
627 {
628 struct ext3_sb_info *sbi = EXT3_SB(sb);
629 const unsigned long last = sbi->s_groups_count;
630 const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
631 unsigned three = 1;
632 unsigned five = 5;
633 unsigned seven = 7;
634 unsigned group;
635 int rest = sb->s_blocksize - size;
636 handle_t *handle;
637 int err = 0, err2;
639 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
640 if (IS_ERR(handle)) {
641 group = 1;
642 err = PTR_ERR(handle);
643 goto exit_err;
644 }
646 while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
647 struct buffer_head *bh;
649 /* Out of journal space, and can't get more - abort - so sad */
650 if (handle->h_buffer_credits == 0 &&
651 ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
652 (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
653 break;
655 bh = sb_getblk(sb, group * bpg + blk_off);
656 if (!bh) {
657 err = -EIO;
658 break;
659 }
660 ext3_debug("update metadata backup %#04lx\n",
661 (unsigned long)bh->b_blocknr);
662 if ((err = ext3_journal_get_write_access(handle, bh)))
663 break;
664 lock_buffer(bh);
665 memcpy(bh->b_data, data, size);
666 if (rest)
667 memset(bh->b_data + size, 0, rest);
668 set_buffer_uptodate(bh);
669 unlock_buffer(bh);
670 ext3_journal_dirty_metadata(handle, bh);
671 brelse(bh);
672 }
673 if ((err2 = ext3_journal_stop(handle)) && !err)
674 err = err2;
676 /*
677 * Ugh! Need to have e2fsck write the backup copies. It is too
678 * late to revert the resize, we shouldn't fail just because of
679 * the backup copies (they are only needed in case of corruption).
680 *
681 * However, if we got here we have a journal problem too, so we
682 * can't really start a transaction to mark the superblock.
683 * Chicken out and just set the flag on the hope it will be written
684 * to disk, and if not - we will simply wait until next fsck.
685 */
686 exit_err:
687 if (err) {
688 ext3_warning(sb, __FUNCTION__,
689 "can't update backup for group %d (err %d), "
690 "forcing fsck on next reboot", group, err);
691 sbi->s_mount_state &= ~EXT3_VALID_FS;
692 sbi->s_es->s_state &= ~cpu_to_le16(EXT3_VALID_FS);
693 mark_buffer_dirty(sbi->s_sbh);
694 }
695 }
697 /* Add group descriptor data to an existing or new group descriptor block.
698 * Ensure we handle all possible error conditions _before_ we start modifying
699 * the filesystem, because we cannot abort the transaction and not have it
700 * write the data to disk.
701 *
702 * If we are on a GDT block boundary, we need to get the reserved GDT block.
703 * Otherwise, we may need to add backup GDT blocks for a sparse group.
704 *
705 * We only need to hold the superblock lock while we are actually adding
706 * in the new group's counts to the superblock. Prior to that we have
707 * not really "added" the group at all. We re-check that we are still
708 * adding in the last group in case things have changed since verifying.
709 */
710 int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
711 {
712 struct ext3_sb_info *sbi = EXT3_SB(sb);
713 struct ext3_super_block *es = sbi->s_es;
714 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
715 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
716 struct buffer_head *primary = NULL;
717 struct ext3_group_desc *gdp;
718 struct inode *inode = NULL;
719 handle_t *handle;
720 int gdb_off, gdb_num;
721 int err, err2;
723 gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
724 gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
726 if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
727 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
728 ext3_warning(sb, __FUNCTION__,
729 "Can't resize non-sparse filesystem further");
730 return -EPERM;
731 }
733 if (reserved_gdb || gdb_off == 0) {
734 if (!EXT3_HAS_COMPAT_FEATURE(sb,
735 EXT3_FEATURE_COMPAT_RESIZE_INODE)){
736 ext3_warning(sb, __FUNCTION__,
737 "No reserved GDT blocks, can't resize");
738 return -EPERM;
739 }
740 inode = iget(sb, EXT3_RESIZE_INO);
741 if (!inode || is_bad_inode(inode)) {
742 ext3_warning(sb, __FUNCTION__,
743 "Error opening resize inode");
744 iput(inode);
745 return -ENOENT;
746 }
747 }
749 if ((err = verify_group_input(sb, input)))
750 goto exit_put;
752 if ((err = setup_new_group_blocks(sb, input)))
753 goto exit_put;
755 /*
756 * We will always be modifying at least the superblock and a GDT
757 * block. If we are adding a group past the last current GDT block,
758 * we will also modify the inode and the dindirect block. If we
759 * are adding a group with superblock/GDT backups we will also
760 * modify each of the reserved GDT dindirect blocks.
761 */
762 handle = ext3_journal_start_sb(sb,
763 ext3_bg_has_super(sb, input->group) ?
764 3 + reserved_gdb : 4);
765 if (IS_ERR(handle)) {
766 err = PTR_ERR(handle);
767 goto exit_put;
768 }
770 lock_super(sb);
771 if (input->group != sbi->s_groups_count) {
772 ext3_warning(sb, __FUNCTION__,
773 "multiple resizers run on filesystem!");
774 err = -EBUSY;
775 goto exit_journal;
776 }
778 if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
779 goto exit_journal;
781 /*
782 * We will only either add reserved group blocks to a backup group
783 * or remove reserved blocks for the first group in a new group block.
784 * Doing both would be mean more complex code, and sane people don't
785 * use non-sparse filesystems anymore. This is already checked above.
786 */
787 if (gdb_off) {
788 primary = sbi->s_group_desc[gdb_num];
789 if ((err = ext3_journal_get_write_access(handle, primary)))
790 goto exit_journal;
792 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
793 (err = reserve_backup_gdb(handle, inode, input)))
794 goto exit_journal;
795 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
796 goto exit_journal;
798 /*
799 * OK, now we've set up the new group. Time to make it active.
800 *
801 * Current kernels don't lock all allocations via lock_super(),
802 * so we have to be safe wrt. concurrent accesses the group
803 * data. So we need to be careful to set all of the relevant
804 * group descriptor data etc. *before* we enable the group.
805 *
806 * The key field here is sbi->s_groups_count: as long as
807 * that retains its old value, nobody is going to access the new
808 * group.
809 *
810 * So first we update all the descriptor metadata for the new
811 * group; then we update the total disk blocks count; then we
812 * update the groups count to enable the group; then finally we
813 * update the free space counts so that the system can start
814 * using the new disk blocks.
815 */
817 /* Update group descriptor block for new group */
818 gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
820 gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
821 gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
822 gdp->bg_inode_table = cpu_to_le32(input->inode_table);
823 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
824 gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
826 /*
827 * Make the new blocks and inodes valid next. We do this before
828 * increasing the group count so that once the group is enabled,
829 * all of its blocks and inodes are already valid.
830 *
831 * We always allocate group-by-group, then block-by-block or
832 * inode-by-inode within a group, so enabling these
833 * blocks/inodes before the group is live won't actually let us
834 * allocate the new space yet.
835 */
836 es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
837 input->blocks_count);
838 es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
839 EXT3_INODES_PER_GROUP(sb));
841 /*
842 * We need to protect s_groups_count against other CPUs seeing
843 * inconsistent state in the superblock.
844 *
845 * The precise rules we use are:
846 *
847 * * Writers of s_groups_count *must* hold lock_super
848 * AND
849 * * Writers must perform a smp_wmb() after updating all dependent
850 * data and before modifying the groups count
851 *
852 * * Readers must hold lock_super() over the access
853 * OR
854 * * Readers must perform an smp_rmb() after reading the groups count
855 * and before reading any dependent data.
856 *
857 * NB. These rules can be relaxed when checking the group count
858 * while freeing data, as we can only allocate from a block
859 * group after serialising against the group count, and we can
860 * only then free after serialising in turn against that
861 * allocation.
862 */
863 smp_wmb();
865 /* Update the global fs size fields */
866 sbi->s_groups_count++;
868 ext3_journal_dirty_metadata(handle, primary);
870 /* Update the reserved block counts only once the new group is
871 * active. */
872 es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
873 input->reserved_blocks);
875 /* Update the free space counts */
876 percpu_counter_mod(&sbi->s_freeblocks_counter,
877 input->free_blocks_count);
878 percpu_counter_mod(&sbi->s_freeinodes_counter,
879 EXT3_INODES_PER_GROUP(sb));
881 ext3_journal_dirty_metadata(handle, sbi->s_sbh);
882 sb->s_dirt = 1;
884 exit_journal:
885 unlock_super(sb);
886 if ((err2 = ext3_journal_stop(handle)) && !err)
887 err = err2;
888 if (!err) {
889 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
890 sizeof(struct ext3_super_block));
891 update_backups(sb, primary->b_blocknr, primary->b_data,
892 primary->b_size);
893 }
894 exit_put:
895 iput(inode);
896 return err;
897 } /* ext3_group_add */
899 /* Extend the filesystem to the new number of blocks specified. This entry
900 * point is only used to extend the current filesystem to the end of the last
901 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
902 * for emergencies (because it has no dependencies on reserved blocks).
903 *
904 * If we _really_ wanted, we could use default values to call ext3_group_add()
905 * allow the "remount" trick to work for arbitrary resizing, assuming enough
906 * GDT blocks are reserved to grow to the desired size.
907 */
908 int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
909 ext3_fsblk_t n_blocks_count)
910 {
911 ext3_fsblk_t o_blocks_count;
912 unsigned long o_groups_count;
913 ext3_grpblk_t last;
914 ext3_grpblk_t add;
915 struct buffer_head * bh;
916 handle_t *handle;
917 int err;
918 unsigned long freed_blocks;
920 /* We don't need to worry about locking wrt other resizers just
921 * yet: we're going to revalidate es->s_blocks_count after
922 * taking lock_super() below. */
923 o_blocks_count = le32_to_cpu(es->s_blocks_count);
924 o_groups_count = EXT3_SB(sb)->s_groups_count;
926 if (test_opt(sb, DEBUG))
927 printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK" uto "E3FSBLK" blocks\n",
928 o_blocks_count, n_blocks_count);
930 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
931 return 0;
933 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
934 printk(KERN_ERR "EXT3-fs: filesystem on %s:"
935 " too large to resize to %lu blocks safely\n",
936 sb->s_id, n_blocks_count);
937 if (sizeof(sector_t) < 8)
938 ext3_warning(sb, __FUNCTION__,
939 "CONFIG_LBD not enabled\n");
940 return -EINVAL;
941 }
943 if (n_blocks_count < o_blocks_count) {
944 ext3_warning(sb, __FUNCTION__,
945 "can't shrink FS - resize aborted");
946 return -EBUSY;
947 }
949 /* Handle the remaining blocks in the last group only. */
950 last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
951 EXT3_BLOCKS_PER_GROUP(sb);
953 if (last == 0) {
954 ext3_warning(sb, __FUNCTION__,
955 "need to use ext2online to resize further");
956 return -EPERM;
957 }
959 add = EXT3_BLOCKS_PER_GROUP(sb) - last;
961 if (o_blocks_count + add > n_blocks_count)
962 add = n_blocks_count - o_blocks_count;
964 if (o_blocks_count + add < n_blocks_count)
965 ext3_warning(sb, __FUNCTION__,
966 "will only finish group ("E3FSBLK
967 " blocks, %u new)",
968 o_blocks_count + add, add);
970 /* See if the device is actually as big as what was requested */
971 bh = sb_bread(sb, o_blocks_count + add -1);
972 if (!bh) {
973 ext3_warning(sb, __FUNCTION__,
974 "can't read last block, resize aborted");
975 return -ENOSPC;
976 }
977 brelse(bh);
979 /* We will update the superblock, one block bitmap, and
980 * one group descriptor via ext3_free_blocks().
981 */
982 handle = ext3_journal_start_sb(sb, 3);
983 if (IS_ERR(handle)) {
984 err = PTR_ERR(handle);
985 ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
986 goto exit_put;
987 }
989 lock_super(sb);
990 if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
991 ext3_warning(sb, __FUNCTION__,
992 "multiple resizers run on filesystem!");
993 unlock_super(sb);
994 err = -EBUSY;
995 goto exit_put;
996 }
998 if ((err = ext3_journal_get_write_access(handle,
999 EXT3_SB(sb)->s_sbh))) {
1000 ext3_warning(sb, __FUNCTION__,
1001 "error %d on journal write access", err);
1002 unlock_super(sb);
1003 ext3_journal_stop(handle);
1004 goto exit_put;
1006 es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
1007 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
1008 sb->s_dirt = 1;
1009 unlock_super(sb);
1010 ext3_debug("freeing blocks %lu through "E3FSBLK"\n", o_blocks_count,
1011 o_blocks_count + add);
1012 ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1013 ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", o_blocks_count,
1014 o_blocks_count + add);
1015 if ((err = ext3_journal_stop(handle)))
1016 goto exit_put;
1017 if (test_opt(sb, DEBUG))
1018 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
1019 le32_to_cpu(es->s_blocks_count));
1020 update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
1021 sizeof(struct ext3_super_block));
1022 exit_put:
1023 return err;
1024 } /* ext3_group_extend */