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1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   *  linux/fs/ext4/resize.c
4   *
5   * Support for resizing an ext4 filesystem while it is mounted.
6   *
7   * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
8   *
9   * This could probably be made into a module, because it is not often in use.
10   */
11  
12  
13  #define EXT4FS_DEBUG
14  
15  #include <linux/errno.h>
16  #include <linux/slab.h>
17  
18  #include "ext4_jbd2.h"
19  
20  struct ext4_rcu_ptr {
21  	struct rcu_head rcu;
22  	void *ptr;
23  };
24  
ext4_rcu_ptr_callback(struct rcu_head * head)25  static void ext4_rcu_ptr_callback(struct rcu_head *head)
26  {
27  	struct ext4_rcu_ptr *ptr;
28  
29  	ptr = container_of(head, struct ext4_rcu_ptr, rcu);
30  	kvfree(ptr->ptr);
31  	kfree(ptr);
32  }
33  
ext4_kvfree_array_rcu(void * to_free)34  void ext4_kvfree_array_rcu(void *to_free)
35  {
36  	struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
37  
38  	if (ptr) {
39  		ptr->ptr = to_free;
40  		call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
41  		return;
42  	}
43  	synchronize_rcu();
44  	kvfree(to_free);
45  }
46  
ext4_resize_begin(struct super_block * sb)47  int ext4_resize_begin(struct super_block *sb)
48  {
49  	struct ext4_sb_info *sbi = EXT4_SB(sb);
50  	int ret = 0;
51  
52  	if (!capable(CAP_SYS_RESOURCE))
53  		return -EPERM;
54  
55  	/*
56  	 * If the reserved GDT blocks is non-zero, the resize_inode feature
57  	 * should always be set.
58  	 */
59  	if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
60  	    !ext4_has_feature_resize_inode(sb)) {
61  		ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
62  		return -EFSCORRUPTED;
63  	}
64  
65  	/*
66  	 * If we are not using the primary superblock/GDT copy don't resize,
67           * because the user tools have no way of handling this.  Probably a
68           * bad time to do it anyways.
69           */
70  	if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
71  	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
72  		ext4_warning(sb, "won't resize using backup superblock at %llu",
73  			(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
74  		return -EPERM;
75  	}
76  
77  	/*
78  	 * We are not allowed to do online-resizing on a filesystem mounted
79  	 * with error, because it can destroy the filesystem easily.
80  	 */
81  	if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
82  		ext4_warning(sb, "There are errors in the filesystem, "
83  			     "so online resizing is not allowed");
84  		return -EPERM;
85  	}
86  
87  	if (ext4_has_feature_sparse_super2(sb)) {
88  		ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
89  		return -EOPNOTSUPP;
90  	}
91  
92  	if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
93  				  &EXT4_SB(sb)->s_ext4_flags))
94  		ret = -EBUSY;
95  
96  	return ret;
97  }
98  
ext4_resize_end(struct super_block * sb)99  void ext4_resize_end(struct super_block *sb)
100  {
101  	clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
102  	smp_mb__after_atomic();
103  }
104  
ext4_meta_bg_first_group(struct super_block * sb,ext4_group_t group)105  static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
106  					     ext4_group_t group) {
107  	return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
108  	       EXT4_DESC_PER_BLOCK_BITS(sb);
109  }
110  
ext4_meta_bg_first_block_no(struct super_block * sb,ext4_group_t group)111  static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
112  					     ext4_group_t group) {
113  	group = ext4_meta_bg_first_group(sb, group);
114  	return ext4_group_first_block_no(sb, group);
115  }
116  
ext4_group_overhead_blocks(struct super_block * sb,ext4_group_t group)117  static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
118  						ext4_group_t group) {
119  	ext4_grpblk_t overhead;
120  	overhead = ext4_bg_num_gdb(sb, group);
121  	if (ext4_bg_has_super(sb, group))
122  		overhead += 1 +
123  			  le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
124  	return overhead;
125  }
126  
127  #define outside(b, first, last)	((b) < (first) || (b) >= (last))
128  #define inside(b, first, last)	((b) >= (first) && (b) < (last))
129  
verify_group_input(struct super_block * sb,struct ext4_new_group_data * input)130  static int verify_group_input(struct super_block *sb,
131  			      struct ext4_new_group_data *input)
132  {
133  	struct ext4_sb_info *sbi = EXT4_SB(sb);
134  	struct ext4_super_block *es = sbi->s_es;
135  	ext4_fsblk_t start = ext4_blocks_count(es);
136  	ext4_fsblk_t end = start + input->blocks_count;
137  	ext4_group_t group = input->group;
138  	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
139  	unsigned overhead;
140  	ext4_fsblk_t metaend;
141  	struct buffer_head *bh = NULL;
142  	ext4_grpblk_t free_blocks_count, offset;
143  	int err = -EINVAL;
144  
145  	if (group != sbi->s_groups_count) {
146  		ext4_warning(sb, "Cannot add at group %u (only %u groups)",
147  			     input->group, sbi->s_groups_count);
148  		return -EINVAL;
149  	}
150  
151  	overhead = ext4_group_overhead_blocks(sb, group);
152  	metaend = start + overhead;
153  	input->free_clusters_count = free_blocks_count =
154  		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
155  
156  	if (test_opt(sb, DEBUG))
157  		printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
158  		       "(%d free, %u reserved)\n",
159  		       ext4_bg_has_super(sb, input->group) ? "normal" :
160  		       "no-super", input->group, input->blocks_count,
161  		       free_blocks_count, input->reserved_blocks);
162  
163  	ext4_get_group_no_and_offset(sb, start, NULL, &offset);
164  	if (offset != 0)
165  			ext4_warning(sb, "Last group not full");
166  	else if (input->reserved_blocks > input->blocks_count / 5)
167  		ext4_warning(sb, "Reserved blocks too high (%u)",
168  			     input->reserved_blocks);
169  	else if (free_blocks_count < 0)
170  		ext4_warning(sb, "Bad blocks count %u",
171  			     input->blocks_count);
172  	else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
173  		err = PTR_ERR(bh);
174  		bh = NULL;
175  		ext4_warning(sb, "Cannot read last block (%llu)",
176  			     end - 1);
177  	} else if (outside(input->block_bitmap, start, end))
178  		ext4_warning(sb, "Block bitmap not in group (block %llu)",
179  			     (unsigned long long)input->block_bitmap);
180  	else if (outside(input->inode_bitmap, start, end))
181  		ext4_warning(sb, "Inode bitmap not in group (block %llu)",
182  			     (unsigned long long)input->inode_bitmap);
183  	else if (outside(input->inode_table, start, end) ||
184  		 outside(itend - 1, start, end))
185  		ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
186  			     (unsigned long long)input->inode_table, itend - 1);
187  	else if (input->inode_bitmap == input->block_bitmap)
188  		ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
189  			     (unsigned long long)input->block_bitmap);
190  	else if (inside(input->block_bitmap, input->inode_table, itend))
191  		ext4_warning(sb, "Block bitmap (%llu) in inode table "
192  			     "(%llu-%llu)",
193  			     (unsigned long long)input->block_bitmap,
194  			     (unsigned long long)input->inode_table, itend - 1);
195  	else if (inside(input->inode_bitmap, input->inode_table, itend))
196  		ext4_warning(sb, "Inode bitmap (%llu) in inode table "
197  			     "(%llu-%llu)",
198  			     (unsigned long long)input->inode_bitmap,
199  			     (unsigned long long)input->inode_table, itend - 1);
200  	else if (inside(input->block_bitmap, start, metaend))
201  		ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
202  			     (unsigned long long)input->block_bitmap,
203  			     start, metaend - 1);
204  	else if (inside(input->inode_bitmap, start, metaend))
205  		ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
206  			     (unsigned long long)input->inode_bitmap,
207  			     start, metaend - 1);
208  	else if (inside(input->inode_table, start, metaend) ||
209  		 inside(itend - 1, start, metaend))
210  		ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
211  			     "(%llu-%llu)",
212  			     (unsigned long long)input->inode_table,
213  			     itend - 1, start, metaend - 1);
214  	else
215  		err = 0;
216  	brelse(bh);
217  
218  	return err;
219  }
220  
221  /*
222   * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
223   * group each time.
224   */
225  struct ext4_new_flex_group_data {
226  	struct ext4_new_group_data *groups;	/* new_group_data for groups
227  						   in the flex group */
228  	__u16 *bg_flags;			/* block group flags of groups
229  						   in @groups */
230  	ext4_group_t resize_bg;			/* number of allocated
231  						   new_group_data */
232  	ext4_group_t count;			/* number of groups in @groups
233  						 */
234  };
235  
236  /*
237   * Avoiding memory allocation failures due to too many groups added each time.
238   */
239  #define MAX_RESIZE_BG				16384
240  
241  /*
242   * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
243   * @flexbg_size.
244   *
245   * Returns NULL on failure otherwise address of the allocated structure.
246   */
alloc_flex_gd(unsigned int flexbg_size)247  static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size)
248  {
249  	struct ext4_new_flex_group_data *flex_gd;
250  
251  	flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
252  	if (flex_gd == NULL)
253  		goto out3;
254  
255  	if (unlikely(flexbg_size > MAX_RESIZE_BG))
256  		flex_gd->resize_bg = MAX_RESIZE_BG;
257  	else
258  		flex_gd->resize_bg = flexbg_size;
259  
260  	flex_gd->groups = kmalloc_array(flex_gd->resize_bg,
261  					sizeof(struct ext4_new_group_data),
262  					GFP_NOFS);
263  	if (flex_gd->groups == NULL)
264  		goto out2;
265  
266  	flex_gd->bg_flags = kmalloc_array(flex_gd->resize_bg, sizeof(__u16),
267  					  GFP_NOFS);
268  	if (flex_gd->bg_flags == NULL)
269  		goto out1;
270  
271  	return flex_gd;
272  
273  out1:
274  	kfree(flex_gd->groups);
275  out2:
276  	kfree(flex_gd);
277  out3:
278  	return NULL;
279  }
280  
free_flex_gd(struct ext4_new_flex_group_data * flex_gd)281  static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
282  {
283  	kfree(flex_gd->bg_flags);
284  	kfree(flex_gd->groups);
285  	kfree(flex_gd);
286  }
287  
288  /*
289   * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
290   * and inode tables for a flex group.
291   *
292   * This function is used by 64bit-resize.  Note that this function allocates
293   * group tables from the 1st group of groups contained by @flexgd, which may
294   * be a partial of a flex group.
295   *
296   * @sb: super block of fs to which the groups belongs
297   *
298   * Returns 0 on a successful allocation of the metadata blocks in the
299   * block group.
300   */
ext4_alloc_group_tables(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd,unsigned int flexbg_size)301  static int ext4_alloc_group_tables(struct super_block *sb,
302  				struct ext4_new_flex_group_data *flex_gd,
303  				unsigned int flexbg_size)
304  {
305  	struct ext4_new_group_data *group_data = flex_gd->groups;
306  	ext4_fsblk_t start_blk;
307  	ext4_fsblk_t last_blk;
308  	ext4_group_t src_group;
309  	ext4_group_t bb_index = 0;
310  	ext4_group_t ib_index = 0;
311  	ext4_group_t it_index = 0;
312  	ext4_group_t group;
313  	ext4_group_t last_group;
314  	unsigned overhead;
315  	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
316  	int i;
317  
318  	BUG_ON(flex_gd->count == 0 || group_data == NULL);
319  
320  	src_group = group_data[0].group;
321  	last_group  = src_group + flex_gd->count - 1;
322  
323  	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
324  	       (last_group & ~(flexbg_size - 1))));
325  next_group:
326  	group = group_data[0].group;
327  	if (src_group >= group_data[0].group + flex_gd->count)
328  		return -ENOSPC;
329  	start_blk = ext4_group_first_block_no(sb, src_group);
330  	last_blk = start_blk + group_data[src_group - group].blocks_count;
331  
332  	overhead = ext4_group_overhead_blocks(sb, src_group);
333  
334  	start_blk += overhead;
335  
336  	/* We collect contiguous blocks as much as possible. */
337  	src_group++;
338  	for (; src_group <= last_group; src_group++) {
339  		overhead = ext4_group_overhead_blocks(sb, src_group);
340  		if (overhead == 0)
341  			last_blk += group_data[src_group - group].blocks_count;
342  		else
343  			break;
344  	}
345  
346  	/* Allocate block bitmaps */
347  	for (; bb_index < flex_gd->count; bb_index++) {
348  		if (start_blk >= last_blk)
349  			goto next_group;
350  		group_data[bb_index].block_bitmap = start_blk++;
351  		group = ext4_get_group_number(sb, start_blk - 1);
352  		group -= group_data[0].group;
353  		group_data[group].mdata_blocks++;
354  		flex_gd->bg_flags[group] &= uninit_mask;
355  	}
356  
357  	/* Allocate inode bitmaps */
358  	for (; ib_index < flex_gd->count; ib_index++) {
359  		if (start_blk >= last_blk)
360  			goto next_group;
361  		group_data[ib_index].inode_bitmap = start_blk++;
362  		group = ext4_get_group_number(sb, start_blk - 1);
363  		group -= group_data[0].group;
364  		group_data[group].mdata_blocks++;
365  		flex_gd->bg_flags[group] &= uninit_mask;
366  	}
367  
368  	/* Allocate inode tables */
369  	for (; it_index < flex_gd->count; it_index++) {
370  		unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
371  		ext4_fsblk_t next_group_start;
372  
373  		if (start_blk + itb > last_blk)
374  			goto next_group;
375  		group_data[it_index].inode_table = start_blk;
376  		group = ext4_get_group_number(sb, start_blk);
377  		next_group_start = ext4_group_first_block_no(sb, group + 1);
378  		group -= group_data[0].group;
379  
380  		if (start_blk + itb > next_group_start) {
381  			flex_gd->bg_flags[group + 1] &= uninit_mask;
382  			overhead = start_blk + itb - next_group_start;
383  			group_data[group + 1].mdata_blocks += overhead;
384  			itb -= overhead;
385  		}
386  
387  		group_data[group].mdata_blocks += itb;
388  		flex_gd->bg_flags[group] &= uninit_mask;
389  		start_blk += EXT4_SB(sb)->s_itb_per_group;
390  	}
391  
392  	/* Update free clusters count to exclude metadata blocks */
393  	for (i = 0; i < flex_gd->count; i++) {
394  		group_data[i].free_clusters_count -=
395  				EXT4_NUM_B2C(EXT4_SB(sb),
396  					     group_data[i].mdata_blocks);
397  	}
398  
399  	if (test_opt(sb, DEBUG)) {
400  		int i;
401  		group = group_data[0].group;
402  
403  		printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
404  		       "%u groups, flexbg size is %u:\n", flex_gd->count,
405  		       flexbg_size);
406  
407  		for (i = 0; i < flex_gd->count; i++) {
408  			ext4_debug(
409  			       "adding %s group %u: %u blocks (%u free, %u mdata blocks)\n",
410  			       ext4_bg_has_super(sb, group + i) ? "normal" :
411  			       "no-super", group + i,
412  			       group_data[i].blocks_count,
413  			       group_data[i].free_clusters_count,
414  			       group_data[i].mdata_blocks);
415  		}
416  	}
417  	return 0;
418  }
419  
bclean(handle_t * handle,struct super_block * sb,ext4_fsblk_t blk)420  static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
421  				  ext4_fsblk_t blk)
422  {
423  	struct buffer_head *bh;
424  	int err;
425  
426  	bh = sb_getblk(sb, blk);
427  	if (unlikely(!bh))
428  		return ERR_PTR(-ENOMEM);
429  	BUFFER_TRACE(bh, "get_write_access");
430  	if ((err = ext4_journal_get_write_access(handle, bh))) {
431  		brelse(bh);
432  		bh = ERR_PTR(err);
433  	} else {
434  		memset(bh->b_data, 0, sb->s_blocksize);
435  		set_buffer_uptodate(bh);
436  	}
437  
438  	return bh;
439  }
440  
441  /*
442   * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
443   * If that fails, restart the transaction & regain write access for the
444   * buffer head which is used for block_bitmap modifications.
445   */
extend_or_restart_transaction(handle_t * handle,int thresh)446  static int extend_or_restart_transaction(handle_t *handle, int thresh)
447  {
448  	int err;
449  
450  	if (ext4_handle_has_enough_credits(handle, thresh))
451  		return 0;
452  
453  	err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
454  	if (err < 0)
455  		return err;
456  	if (err) {
457  		err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA);
458  		if (err)
459  			return err;
460  	}
461  
462  	return 0;
463  }
464  
465  /*
466   * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
467   *
468   * Helper function for ext4_setup_new_group_blocks() which set .
469   *
470   * @sb: super block
471   * @handle: journal handle
472   * @flex_gd: flex group data
473   */
set_flexbg_block_bitmap(struct super_block * sb,handle_t * handle,struct ext4_new_flex_group_data * flex_gd,ext4_fsblk_t first_cluster,ext4_fsblk_t last_cluster)474  static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
475  			struct ext4_new_flex_group_data *flex_gd,
476  			ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
477  {
478  	struct ext4_sb_info *sbi = EXT4_SB(sb);
479  	ext4_group_t count = last_cluster - first_cluster + 1;
480  	ext4_group_t count2;
481  
482  	ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
483  		   last_cluster);
484  	for (count2 = count; count > 0;
485  	     count -= count2, first_cluster += count2) {
486  		ext4_fsblk_t start;
487  		struct buffer_head *bh;
488  		ext4_group_t group;
489  		int err;
490  
491  		group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
492  		start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
493  		group -= flex_gd->groups[0].group;
494  
495  		count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
496  		if (count2 > count)
497  			count2 = count;
498  
499  		if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
500  			BUG_ON(flex_gd->count > 1);
501  			continue;
502  		}
503  
504  		err = extend_or_restart_transaction(handle, 1);
505  		if (err)
506  			return err;
507  
508  		bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
509  		if (unlikely(!bh))
510  			return -ENOMEM;
511  
512  		BUFFER_TRACE(bh, "get_write_access");
513  		err = ext4_journal_get_write_access(handle, bh);
514  		if (err) {
515  			brelse(bh);
516  			return err;
517  		}
518  		ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
519  			   first_cluster, first_cluster - start, count2);
520  		ext4_set_bits(bh->b_data, first_cluster - start, count2);
521  
522  		err = ext4_handle_dirty_metadata(handle, NULL, bh);
523  		brelse(bh);
524  		if (unlikely(err))
525  			return err;
526  	}
527  
528  	return 0;
529  }
530  
531  /*
532   * Set up the block and inode bitmaps, and the inode table for the new groups.
533   * This doesn't need to be part of the main transaction, since we are only
534   * changing blocks outside the actual filesystem.  We still do journaling to
535   * ensure the recovery is correct in case of a failure just after resize.
536   * If any part of this fails, we simply abort the resize.
537   *
538   * setup_new_flex_group_blocks handles a flex group as follow:
539   *  1. copy super block and GDT, and initialize group tables if necessary.
540   *     In this step, we only set bits in blocks bitmaps for blocks taken by
541   *     super block and GDT.
542   *  2. allocate group tables in block bitmaps, that is, set bits in block
543   *     bitmap for blocks taken by group tables.
544   */
setup_new_flex_group_blocks(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd)545  static int setup_new_flex_group_blocks(struct super_block *sb,
546  				struct ext4_new_flex_group_data *flex_gd)
547  {
548  	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
549  	ext4_fsblk_t start;
550  	ext4_fsblk_t block;
551  	struct ext4_sb_info *sbi = EXT4_SB(sb);
552  	struct ext4_super_block *es = sbi->s_es;
553  	struct ext4_new_group_data *group_data = flex_gd->groups;
554  	__u16 *bg_flags = flex_gd->bg_flags;
555  	handle_t *handle;
556  	ext4_group_t group, count;
557  	struct buffer_head *bh = NULL;
558  	int reserved_gdb, i, j, err = 0, err2;
559  	int meta_bg;
560  
561  	BUG_ON(!flex_gd->count || !group_data ||
562  	       group_data[0].group != sbi->s_groups_count);
563  
564  	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
565  	meta_bg = ext4_has_feature_meta_bg(sb);
566  
567  	/* This transaction may be extended/restarted along the way */
568  	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
569  	if (IS_ERR(handle))
570  		return PTR_ERR(handle);
571  
572  	group = group_data[0].group;
573  	for (i = 0; i < flex_gd->count; i++, group++) {
574  		unsigned long gdblocks;
575  		ext4_grpblk_t overhead;
576  
577  		gdblocks = ext4_bg_num_gdb(sb, group);
578  		start = ext4_group_first_block_no(sb, group);
579  
580  		if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
581  			goto handle_itb;
582  
583  		if (meta_bg == 1)
584  			goto handle_itb;
585  
586  		block = start + ext4_bg_has_super(sb, group);
587  		/* Copy all of the GDT blocks into the backup in this group */
588  		for (j = 0; j < gdblocks; j++, block++) {
589  			struct buffer_head *gdb;
590  
591  			ext4_debug("update backup group %#04llx\n", block);
592  			err = extend_or_restart_transaction(handle, 1);
593  			if (err)
594  				goto out;
595  
596  			gdb = sb_getblk(sb, block);
597  			if (unlikely(!gdb)) {
598  				err = -ENOMEM;
599  				goto out;
600  			}
601  
602  			BUFFER_TRACE(gdb, "get_write_access");
603  			err = ext4_journal_get_write_access(handle, gdb);
604  			if (err) {
605  				brelse(gdb);
606  				goto out;
607  			}
608  			memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
609  				s_group_desc, j)->b_data, gdb->b_size);
610  			set_buffer_uptodate(gdb);
611  
612  			err = ext4_handle_dirty_metadata(handle, NULL, gdb);
613  			if (unlikely(err)) {
614  				brelse(gdb);
615  				goto out;
616  			}
617  			brelse(gdb);
618  		}
619  
620  		/* Zero out all of the reserved backup group descriptor
621  		 * table blocks
622  		 */
623  		if (ext4_bg_has_super(sb, group)) {
624  			err = sb_issue_zeroout(sb, gdblocks + start + 1,
625  					reserved_gdb, GFP_NOFS);
626  			if (err)
627  				goto out;
628  		}
629  
630  handle_itb:
631  		/* Initialize group tables of the grop @group */
632  		if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
633  			goto handle_bb;
634  
635  		/* Zero out all of the inode table blocks */
636  		block = group_data[i].inode_table;
637  		ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
638  			   block, sbi->s_itb_per_group);
639  		err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
640  				       GFP_NOFS);
641  		if (err)
642  			goto out;
643  
644  handle_bb:
645  		if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
646  			goto handle_ib;
647  
648  		/* Initialize block bitmap of the @group */
649  		block = group_data[i].block_bitmap;
650  		err = extend_or_restart_transaction(handle, 1);
651  		if (err)
652  			goto out;
653  
654  		bh = bclean(handle, sb, block);
655  		if (IS_ERR(bh)) {
656  			err = PTR_ERR(bh);
657  			goto out;
658  		}
659  		overhead = ext4_group_overhead_blocks(sb, group);
660  		if (overhead != 0) {
661  			ext4_debug("mark backup superblock %#04llx (+0)\n",
662  				   start);
663  			ext4_set_bits(bh->b_data, 0,
664  				      EXT4_NUM_B2C(sbi, overhead));
665  		}
666  		ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
667  				     sb->s_blocksize * 8, bh->b_data);
668  		err = ext4_handle_dirty_metadata(handle, NULL, bh);
669  		brelse(bh);
670  		if (err)
671  			goto out;
672  
673  handle_ib:
674  		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
675  			continue;
676  
677  		/* Initialize inode bitmap of the @group */
678  		block = group_data[i].inode_bitmap;
679  		err = extend_or_restart_transaction(handle, 1);
680  		if (err)
681  			goto out;
682  		/* Mark unused entries in inode bitmap used */
683  		bh = bclean(handle, sb, block);
684  		if (IS_ERR(bh)) {
685  			err = PTR_ERR(bh);
686  			goto out;
687  		}
688  
689  		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
690  				     sb->s_blocksize * 8, bh->b_data);
691  		err = ext4_handle_dirty_metadata(handle, NULL, bh);
692  		brelse(bh);
693  		if (err)
694  			goto out;
695  	}
696  
697  	/* Mark group tables in block bitmap */
698  	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
699  		count = group_table_count[j];
700  		start = (&group_data[0].block_bitmap)[j];
701  		block = start;
702  		for (i = 1; i < flex_gd->count; i++) {
703  			block += group_table_count[j];
704  			if (block == (&group_data[i].block_bitmap)[j]) {
705  				count += group_table_count[j];
706  				continue;
707  			}
708  			err = set_flexbg_block_bitmap(sb, handle,
709  						      flex_gd,
710  						      EXT4_B2C(sbi, start),
711  						      EXT4_B2C(sbi,
712  							       start + count
713  							       - 1));
714  			if (err)
715  				goto out;
716  			count = group_table_count[j];
717  			start = (&group_data[i].block_bitmap)[j];
718  			block = start;
719  		}
720  
721  		if (count) {
722  			err = set_flexbg_block_bitmap(sb, handle,
723  						      flex_gd,
724  						      EXT4_B2C(sbi, start),
725  						      EXT4_B2C(sbi,
726  							       start + count
727  							       - 1));
728  			if (err)
729  				goto out;
730  		}
731  	}
732  
733  out:
734  	err2 = ext4_journal_stop(handle);
735  	if (err2 && !err)
736  		err = err2;
737  
738  	return err;
739  }
740  
741  /*
742   * Iterate through the groups which hold BACKUP superblock/GDT copies in an
743   * ext4 filesystem.  The counters should be initialized to 1, 5, and 7 before
744   * calling this for the first time.  In a sparse filesystem it will be the
745   * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
746   * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
747   */
ext4_list_backups(struct super_block * sb,unsigned * three,unsigned * five,unsigned * seven)748  static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
749  				  unsigned *five, unsigned *seven)
750  {
751  	unsigned *min = three;
752  	int mult = 3;
753  	unsigned ret;
754  
755  	if (!ext4_has_feature_sparse_super(sb)) {
756  		ret = *min;
757  		*min += 1;
758  		return ret;
759  	}
760  
761  	if (*five < *min) {
762  		min = five;
763  		mult = 5;
764  	}
765  	if (*seven < *min) {
766  		min = seven;
767  		mult = 7;
768  	}
769  
770  	ret = *min;
771  	*min *= mult;
772  
773  	return ret;
774  }
775  
776  /*
777   * Check that all of the backup GDT blocks are held in the primary GDT block.
778   * It is assumed that they are stored in group order.  Returns the number of
779   * groups in current filesystem that have BACKUPS, or -ve error code.
780   */
verify_reserved_gdb(struct super_block * sb,ext4_group_t end,struct buffer_head * primary)781  static int verify_reserved_gdb(struct super_block *sb,
782  			       ext4_group_t end,
783  			       struct buffer_head *primary)
784  {
785  	const ext4_fsblk_t blk = primary->b_blocknr;
786  	unsigned three = 1;
787  	unsigned five = 5;
788  	unsigned seven = 7;
789  	unsigned grp;
790  	__le32 *p = (__le32 *)primary->b_data;
791  	int gdbackups = 0;
792  
793  	while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
794  		if (le32_to_cpu(*p++) !=
795  		    grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
796  			ext4_warning(sb, "reserved GDT %llu"
797  				     " missing grp %d (%llu)",
798  				     blk, grp,
799  				     grp *
800  				     (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
801  				     blk);
802  			return -EINVAL;
803  		}
804  		if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
805  			return -EFBIG;
806  	}
807  
808  	return gdbackups;
809  }
810  
811  /*
812   * Called when we need to bring a reserved group descriptor table block into
813   * use from the resize inode.  The primary copy of the new GDT block currently
814   * is an indirect block (under the double indirect block in the resize inode).
815   * The new backup GDT blocks will be stored as leaf blocks in this indirect
816   * block, in group order.  Even though we know all the block numbers we need,
817   * we check to ensure that the resize inode has actually reserved these blocks.
818   *
819   * Don't need to update the block bitmaps because the blocks are still in use.
820   *
821   * We get all of the error cases out of the way, so that we are sure to not
822   * fail once we start modifying the data on disk, because JBD has no rollback.
823   */
add_new_gdb(handle_t * handle,struct inode * inode,ext4_group_t group)824  static int add_new_gdb(handle_t *handle, struct inode *inode,
825  		       ext4_group_t group)
826  {
827  	struct super_block *sb = inode->i_sb;
828  	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
829  	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
830  	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
831  	struct buffer_head **o_group_desc, **n_group_desc = NULL;
832  	struct buffer_head *dind = NULL;
833  	struct buffer_head *gdb_bh = NULL;
834  	int gdbackups;
835  	struct ext4_iloc iloc = { .bh = NULL };
836  	__le32 *data;
837  	int err;
838  
839  	if (test_opt(sb, DEBUG))
840  		printk(KERN_DEBUG
841  		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
842  		       gdb_num);
843  
844  	gdb_bh = ext4_sb_bread(sb, gdblock, 0);
845  	if (IS_ERR(gdb_bh))
846  		return PTR_ERR(gdb_bh);
847  
848  	gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
849  	if (gdbackups < 0) {
850  		err = gdbackups;
851  		goto errout;
852  	}
853  
854  	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
855  	dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
856  	if (IS_ERR(dind)) {
857  		err = PTR_ERR(dind);
858  		dind = NULL;
859  		goto errout;
860  	}
861  
862  	data = (__le32 *)dind->b_data;
863  	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
864  		ext4_warning(sb, "new group %u GDT block %llu not reserved",
865  			     group, gdblock);
866  		err = -EINVAL;
867  		goto errout;
868  	}
869  
870  	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
871  	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
872  	if (unlikely(err))
873  		goto errout;
874  
875  	BUFFER_TRACE(gdb_bh, "get_write_access");
876  	err = ext4_journal_get_write_access(handle, gdb_bh);
877  	if (unlikely(err))
878  		goto errout;
879  
880  	BUFFER_TRACE(dind, "get_write_access");
881  	err = ext4_journal_get_write_access(handle, dind);
882  	if (unlikely(err)) {
883  		ext4_std_error(sb, err);
884  		goto errout;
885  	}
886  
887  	/* ext4_reserve_inode_write() gets a reference on the iloc */
888  	err = ext4_reserve_inode_write(handle, inode, &iloc);
889  	if (unlikely(err))
890  		goto errout;
891  
892  	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
893  				     sizeof(struct buffer_head *),
894  				     GFP_NOFS);
895  	if (!n_group_desc) {
896  		err = -ENOMEM;
897  		ext4_warning(sb, "not enough memory for %lu groups",
898  			     gdb_num + 1);
899  		goto errout;
900  	}
901  
902  	/*
903  	 * Finally, we have all of the possible failures behind us...
904  	 *
905  	 * Remove new GDT block from inode double-indirect block and clear out
906  	 * the new GDT block for use (which also "frees" the backup GDT blocks
907  	 * from the reserved inode).  We don't need to change the bitmaps for
908  	 * these blocks, because they are marked as in-use from being in the
909  	 * reserved inode, and will become GDT blocks (primary and backup).
910  	 */
911  	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
912  	err = ext4_handle_dirty_metadata(handle, NULL, dind);
913  	if (unlikely(err)) {
914  		ext4_std_error(sb, err);
915  		goto errout;
916  	}
917  	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
918  			   (9 - EXT4_SB(sb)->s_cluster_bits);
919  	ext4_mark_iloc_dirty(handle, inode, &iloc);
920  	memset(gdb_bh->b_data, 0, sb->s_blocksize);
921  	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
922  	if (unlikely(err)) {
923  		ext4_std_error(sb, err);
924  		iloc.bh = NULL;
925  		goto errout;
926  	}
927  	brelse(dind);
928  
929  	rcu_read_lock();
930  	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
931  	memcpy(n_group_desc, o_group_desc,
932  	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
933  	rcu_read_unlock();
934  	n_group_desc[gdb_num] = gdb_bh;
935  	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
936  	EXT4_SB(sb)->s_gdb_count++;
937  	ext4_kvfree_array_rcu(o_group_desc);
938  
939  	le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
940  	err = ext4_handle_dirty_super(handle, sb);
941  	if (err)
942  		ext4_std_error(sb, err);
943  	return err;
944  errout:
945  	kvfree(n_group_desc);
946  	brelse(iloc.bh);
947  	brelse(dind);
948  	brelse(gdb_bh);
949  
950  	ext4_debug("leaving with error %d\n", err);
951  	return err;
952  }
953  
954  /*
955   * add_new_gdb_meta_bg is the sister of add_new_gdb.
956   */
add_new_gdb_meta_bg(struct super_block * sb,handle_t * handle,ext4_group_t group)957  static int add_new_gdb_meta_bg(struct super_block *sb,
958  			       handle_t *handle, ext4_group_t group) {
959  	ext4_fsblk_t gdblock;
960  	struct buffer_head *gdb_bh;
961  	struct buffer_head **o_group_desc, **n_group_desc;
962  	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
963  	int err;
964  
965  	gdblock = ext4_meta_bg_first_block_no(sb, group) +
966  		   ext4_bg_has_super(sb, group);
967  	gdb_bh = ext4_sb_bread(sb, gdblock, 0);
968  	if (IS_ERR(gdb_bh))
969  		return PTR_ERR(gdb_bh);
970  	n_group_desc = ext4_kvmalloc((gdb_num + 1) *
971  				     sizeof(struct buffer_head *),
972  				     GFP_NOFS);
973  	if (!n_group_desc) {
974  		brelse(gdb_bh);
975  		err = -ENOMEM;
976  		ext4_warning(sb, "not enough memory for %lu groups",
977  			     gdb_num + 1);
978  		return err;
979  	}
980  
981  	rcu_read_lock();
982  	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
983  	memcpy(n_group_desc, o_group_desc,
984  	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
985  	rcu_read_unlock();
986  	n_group_desc[gdb_num] = gdb_bh;
987  
988  	BUFFER_TRACE(gdb_bh, "get_write_access");
989  	err = ext4_journal_get_write_access(handle, gdb_bh);
990  	if (err) {
991  		kvfree(n_group_desc);
992  		brelse(gdb_bh);
993  		return err;
994  	}
995  
996  	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
997  	EXT4_SB(sb)->s_gdb_count++;
998  	ext4_kvfree_array_rcu(o_group_desc);
999  	return err;
1000  }
1001  
1002  /*
1003   * Called when we are adding a new group which has a backup copy of each of
1004   * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
1005   * We need to add these reserved backup GDT blocks to the resize inode, so
1006   * that they are kept for future resizing and not allocated to files.
1007   *
1008   * Each reserved backup GDT block will go into a different indirect block.
1009   * The indirect blocks are actually the primary reserved GDT blocks,
1010   * so we know in advance what their block numbers are.  We only get the
1011   * double-indirect block to verify it is pointing to the primary reserved
1012   * GDT blocks so we don't overwrite a data block by accident.  The reserved
1013   * backup GDT blocks are stored in their reserved primary GDT block.
1014   */
reserve_backup_gdb(handle_t * handle,struct inode * inode,ext4_group_t group)1015  static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
1016  			      ext4_group_t group)
1017  {
1018  	struct super_block *sb = inode->i_sb;
1019  	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1020  	int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1021  	struct buffer_head **primary;
1022  	struct buffer_head *dind;
1023  	struct ext4_iloc iloc;
1024  	ext4_fsblk_t blk;
1025  	__le32 *data, *end;
1026  	int gdbackups = 0;
1027  	int res, i;
1028  	int err;
1029  
1030  	primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1031  	if (!primary)
1032  		return -ENOMEM;
1033  
1034  	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1035  	dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1036  	if (IS_ERR(dind)) {
1037  		err = PTR_ERR(dind);
1038  		dind = NULL;
1039  		goto exit_free;
1040  	}
1041  
1042  	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1043  	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1044  					 EXT4_ADDR_PER_BLOCK(sb));
1045  	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1046  
1047  	/* Get each reserved primary GDT block and verify it holds backups */
1048  	for (res = 0; res < reserved_gdb; res++, blk++) {
1049  		if (le32_to_cpu(*data) != blk) {
1050  			ext4_warning(sb, "reserved block %llu"
1051  				     " not at offset %ld",
1052  				     blk,
1053  				     (long)(data - (__le32 *)dind->b_data));
1054  			err = -EINVAL;
1055  			goto exit_bh;
1056  		}
1057  		primary[res] = ext4_sb_bread(sb, blk, 0);
1058  		if (IS_ERR(primary[res])) {
1059  			err = PTR_ERR(primary[res]);
1060  			primary[res] = NULL;
1061  			goto exit_bh;
1062  		}
1063  		gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1064  		if (gdbackups < 0) {
1065  			brelse(primary[res]);
1066  			err = gdbackups;
1067  			goto exit_bh;
1068  		}
1069  		if (++data >= end)
1070  			data = (__le32 *)dind->b_data;
1071  	}
1072  
1073  	for (i = 0; i < reserved_gdb; i++) {
1074  		BUFFER_TRACE(primary[i], "get_write_access");
1075  		if ((err = ext4_journal_get_write_access(handle, primary[i])))
1076  			goto exit_bh;
1077  	}
1078  
1079  	if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1080  		goto exit_bh;
1081  
1082  	/*
1083  	 * Finally we can add each of the reserved backup GDT blocks from
1084  	 * the new group to its reserved primary GDT block.
1085  	 */
1086  	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1087  	for (i = 0; i < reserved_gdb; i++) {
1088  		int err2;
1089  		data = (__le32 *)primary[i]->b_data;
1090  		/* printk("reserving backup %lu[%u] = %lu\n",
1091  		       primary[i]->b_blocknr, gdbackups,
1092  		       blk + primary[i]->b_blocknr); */
1093  		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1094  		err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1095  		if (!err)
1096  			err = err2;
1097  	}
1098  
1099  	inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1100  	ext4_mark_iloc_dirty(handle, inode, &iloc);
1101  
1102  exit_bh:
1103  	while (--res >= 0)
1104  		brelse(primary[res]);
1105  	brelse(dind);
1106  
1107  exit_free:
1108  	kfree(primary);
1109  
1110  	return err;
1111  }
1112  
1113  /*
1114   * Update the backup copies of the ext4 metadata.  These don't need to be part
1115   * of the main resize transaction, because e2fsck will re-write them if there
1116   * is a problem (basically only OOM will cause a problem).  However, we
1117   * _should_ update the backups if possible, in case the primary gets trashed
1118   * for some reason and we need to run e2fsck from a backup superblock.  The
1119   * important part is that the new block and inode counts are in the backup
1120   * superblocks, and the location of the new group metadata in the GDT backups.
1121   *
1122   * We do not need take the s_resize_lock for this, because these
1123   * blocks are not otherwise touched by the filesystem code when it is
1124   * mounted.  We don't need to worry about last changing from
1125   * sbi->s_groups_count, because the worst that can happen is that we
1126   * do not copy the full number of backups at this time.  The resize
1127   * which changed s_groups_count will backup again.
1128   */
update_backups(struct super_block * sb,sector_t blk_off,char * data,int size,int meta_bg)1129  static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1130  			   int size, int meta_bg)
1131  {
1132  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1133  	ext4_group_t last;
1134  	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1135  	unsigned three = 1;
1136  	unsigned five = 5;
1137  	unsigned seven = 7;
1138  	ext4_group_t group = 0;
1139  	int rest = sb->s_blocksize - size;
1140  	handle_t *handle;
1141  	int err = 0, err2;
1142  
1143  	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1144  	if (IS_ERR(handle)) {
1145  		group = 1;
1146  		err = PTR_ERR(handle);
1147  		goto exit_err;
1148  	}
1149  
1150  	if (meta_bg == 0) {
1151  		group = ext4_list_backups(sb, &three, &five, &seven);
1152  		last = sbi->s_groups_count;
1153  	} else {
1154  		group = ext4_get_group_number(sb, blk_off) + 1;
1155  		last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1156  	}
1157  
1158  	while (group < sbi->s_groups_count) {
1159  		struct buffer_head *bh;
1160  		ext4_fsblk_t backup_block;
1161  
1162  		/* Out of journal space, and can't get more - abort - so sad */
1163  		if (ext4_handle_valid(handle) &&
1164  		    handle->h_buffer_credits == 0 &&
1165  		    ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
1166  		    (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
1167  			break;
1168  
1169  		if (meta_bg == 0)
1170  			backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1171  		else
1172  			backup_block = (ext4_group_first_block_no(sb, group) +
1173  					ext4_bg_has_super(sb, group));
1174  
1175  		bh = sb_getblk(sb, backup_block);
1176  		if (unlikely(!bh)) {
1177  			err = -ENOMEM;
1178  			break;
1179  		}
1180  		ext4_debug("update metadata backup %llu(+%llu)\n",
1181  			   backup_block, backup_block -
1182  			   ext4_group_first_block_no(sb, group));
1183  		BUFFER_TRACE(bh, "get_write_access");
1184  		if ((err = ext4_journal_get_write_access(handle, bh))) {
1185  			brelse(bh);
1186  			break;
1187  		}
1188  		lock_buffer(bh);
1189  		memcpy(bh->b_data, data, size);
1190  		if (rest)
1191  			memset(bh->b_data + size, 0, rest);
1192  		set_buffer_uptodate(bh);
1193  		unlock_buffer(bh);
1194  		err = ext4_handle_dirty_metadata(handle, NULL, bh);
1195  		if (unlikely(err))
1196  			ext4_std_error(sb, err);
1197  		brelse(bh);
1198  
1199  		if (meta_bg == 0)
1200  			group = ext4_list_backups(sb, &three, &five, &seven);
1201  		else if (group == last)
1202  			break;
1203  		else
1204  			group = last;
1205  	}
1206  	if ((err2 = ext4_journal_stop(handle)) && !err)
1207  		err = err2;
1208  
1209  	/*
1210  	 * Ugh! Need to have e2fsck write the backup copies.  It is too
1211  	 * late to revert the resize, we shouldn't fail just because of
1212  	 * the backup copies (they are only needed in case of corruption).
1213  	 *
1214  	 * However, if we got here we have a journal problem too, so we
1215  	 * can't really start a transaction to mark the superblock.
1216  	 * Chicken out and just set the flag on the hope it will be written
1217  	 * to disk, and if not - we will simply wait until next fsck.
1218  	 */
1219  exit_err:
1220  	if (err) {
1221  		ext4_warning(sb, "can't update backup for group %u (err %d), "
1222  			     "forcing fsck on next reboot", group, err);
1223  		sbi->s_mount_state &= ~EXT4_VALID_FS;
1224  		sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1225  		mark_buffer_dirty(sbi->s_sbh);
1226  	}
1227  }
1228  
1229  /*
1230   * ext4_add_new_descs() adds @count group descriptor of groups
1231   * starting at @group
1232   *
1233   * @handle: journal handle
1234   * @sb: super block
1235   * @group: the group no. of the first group desc to be added
1236   * @resize_inode: the resize inode
1237   * @count: number of group descriptors to be added
1238   */
ext4_add_new_descs(handle_t * handle,struct super_block * sb,ext4_group_t group,struct inode * resize_inode,ext4_group_t count)1239  static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1240  			      ext4_group_t group, struct inode *resize_inode,
1241  			      ext4_group_t count)
1242  {
1243  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1244  	struct ext4_super_block *es = sbi->s_es;
1245  	struct buffer_head *gdb_bh;
1246  	int i, gdb_off, gdb_num, err = 0;
1247  	int meta_bg;
1248  
1249  	meta_bg = ext4_has_feature_meta_bg(sb);
1250  	for (i = 0; i < count; i++, group++) {
1251  		int reserved_gdb = ext4_bg_has_super(sb, group) ?
1252  			le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1253  
1254  		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1255  		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1256  
1257  		/*
1258  		 * We will only either add reserved group blocks to a backup group
1259  		 * or remove reserved blocks for the first group in a new group block.
1260  		 * Doing both would be mean more complex code, and sane people don't
1261  		 * use non-sparse filesystems anymore.  This is already checked above.
1262  		 */
1263  		if (gdb_off) {
1264  			gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1265  						     gdb_num);
1266  			BUFFER_TRACE(gdb_bh, "get_write_access");
1267  			err = ext4_journal_get_write_access(handle, gdb_bh);
1268  
1269  			if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1270  				err = reserve_backup_gdb(handle, resize_inode, group);
1271  		} else if (meta_bg != 0) {
1272  			err = add_new_gdb_meta_bg(sb, handle, group);
1273  		} else {
1274  			err = add_new_gdb(handle, resize_inode, group);
1275  		}
1276  		if (err)
1277  			break;
1278  	}
1279  	return err;
1280  }
1281  
ext4_get_bitmap(struct super_block * sb,__u64 block)1282  static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1283  {
1284  	struct buffer_head *bh = sb_getblk(sb, block);
1285  	if (unlikely(!bh))
1286  		return NULL;
1287  	if (!bh_uptodate_or_lock(bh)) {
1288  		if (bh_submit_read(bh) < 0) {
1289  			brelse(bh);
1290  			return NULL;
1291  		}
1292  	}
1293  
1294  	return bh;
1295  }
1296  
ext4_set_bitmap_checksums(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct ext4_new_group_data * group_data)1297  static int ext4_set_bitmap_checksums(struct super_block *sb,
1298  				     ext4_group_t group,
1299  				     struct ext4_group_desc *gdp,
1300  				     struct ext4_new_group_data *group_data)
1301  {
1302  	struct buffer_head *bh;
1303  
1304  	if (!ext4_has_metadata_csum(sb))
1305  		return 0;
1306  
1307  	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1308  	if (!bh)
1309  		return -EIO;
1310  	ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1311  				   EXT4_INODES_PER_GROUP(sb) / 8);
1312  	brelse(bh);
1313  
1314  	bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1315  	if (!bh)
1316  		return -EIO;
1317  	ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1318  	brelse(bh);
1319  
1320  	return 0;
1321  }
1322  
1323  /*
1324   * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1325   */
ext4_setup_new_descs(handle_t * handle,struct super_block * sb,struct ext4_new_flex_group_data * flex_gd)1326  static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1327  				struct ext4_new_flex_group_data *flex_gd)
1328  {
1329  	struct ext4_new_group_data	*group_data = flex_gd->groups;
1330  	struct ext4_group_desc		*gdp;
1331  	struct ext4_sb_info		*sbi = EXT4_SB(sb);
1332  	struct buffer_head		*gdb_bh;
1333  	ext4_group_t			group;
1334  	__u16				*bg_flags = flex_gd->bg_flags;
1335  	int				i, gdb_off, gdb_num, err = 0;
1336  
1337  
1338  	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1339  		group = group_data->group;
1340  
1341  		gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1342  		gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1343  
1344  		/*
1345  		 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1346  		 */
1347  		gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1348  		/* Update group descriptor block for new group */
1349  		gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1350  						 gdb_off * EXT4_DESC_SIZE(sb));
1351  
1352  		memset(gdp, 0, EXT4_DESC_SIZE(sb));
1353  		ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1354  		ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1355  		err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1356  		if (err) {
1357  			ext4_std_error(sb, err);
1358  			break;
1359  		}
1360  
1361  		ext4_inode_table_set(sb, gdp, group_data->inode_table);
1362  		ext4_free_group_clusters_set(sb, gdp,
1363  					     group_data->free_clusters_count);
1364  		ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1365  		if (ext4_has_group_desc_csum(sb))
1366  			ext4_itable_unused_set(sb, gdp,
1367  					       EXT4_INODES_PER_GROUP(sb));
1368  		gdp->bg_flags = cpu_to_le16(*bg_flags);
1369  		ext4_group_desc_csum_set(sb, group, gdp);
1370  
1371  		err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1372  		if (unlikely(err)) {
1373  			ext4_std_error(sb, err);
1374  			break;
1375  		}
1376  
1377  		/*
1378  		 * We can allocate memory for mb_alloc based on the new group
1379  		 * descriptor
1380  		 */
1381  		err = ext4_mb_add_groupinfo(sb, group, gdp);
1382  		if (err)
1383  			break;
1384  	}
1385  	return err;
1386  }
1387  
1388  /*
1389   * ext4_update_super() updates the super block so that the newly added
1390   * groups can be seen by the filesystem.
1391   *
1392   * @sb: super block
1393   * @flex_gd: new added groups
1394   */
ext4_update_super(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd)1395  static void ext4_update_super(struct super_block *sb,
1396  			     struct ext4_new_flex_group_data *flex_gd)
1397  {
1398  	ext4_fsblk_t blocks_count = 0;
1399  	ext4_fsblk_t free_blocks = 0;
1400  	ext4_fsblk_t reserved_blocks = 0;
1401  	struct ext4_new_group_data *group_data = flex_gd->groups;
1402  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1403  	struct ext4_super_block *es = sbi->s_es;
1404  	int i;
1405  
1406  	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1407  	/*
1408  	 * Make the new blocks and inodes valid next.  We do this before
1409  	 * increasing the group count so that once the group is enabled,
1410  	 * all of its blocks and inodes are already valid.
1411  	 *
1412  	 * We always allocate group-by-group, then block-by-block or
1413  	 * inode-by-inode within a group, so enabling these
1414  	 * blocks/inodes before the group is live won't actually let us
1415  	 * allocate the new space yet.
1416  	 */
1417  	for (i = 0; i < flex_gd->count; i++) {
1418  		blocks_count += group_data[i].blocks_count;
1419  		free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1420  	}
1421  
1422  	reserved_blocks = ext4_r_blocks_count(es) * 100;
1423  	reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1424  	reserved_blocks *= blocks_count;
1425  	do_div(reserved_blocks, 100);
1426  
1427  	ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1428  	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1429  	le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1430  		     flex_gd->count);
1431  	le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1432  		     flex_gd->count);
1433  
1434  	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1435  	/*
1436  	 * We need to protect s_groups_count against other CPUs seeing
1437  	 * inconsistent state in the superblock.
1438  	 *
1439  	 * The precise rules we use are:
1440  	 *
1441  	 * * Writers must perform a smp_wmb() after updating all
1442  	 *   dependent data and before modifying the groups count
1443  	 *
1444  	 * * Readers must perform an smp_rmb() after reading the groups
1445  	 *   count and before reading any dependent data.
1446  	 *
1447  	 * NB. These rules can be relaxed when checking the group count
1448  	 * while freeing data, as we can only allocate from a block
1449  	 * group after serialising against the group count, and we can
1450  	 * only then free after serialising in turn against that
1451  	 * allocation.
1452  	 */
1453  	smp_wmb();
1454  
1455  	/* Update the global fs size fields */
1456  	sbi->s_groups_count += flex_gd->count;
1457  	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1458  			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1459  
1460  	/* Update the reserved block counts only once the new group is
1461  	 * active. */
1462  	ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1463  				reserved_blocks);
1464  
1465  	/* Update the free space counts */
1466  	percpu_counter_add(&sbi->s_freeclusters_counter,
1467  			   EXT4_NUM_B2C(sbi, free_blocks));
1468  	percpu_counter_add(&sbi->s_freeinodes_counter,
1469  			   EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1470  
1471  	ext4_debug("free blocks count %llu",
1472  		   percpu_counter_read(&sbi->s_freeclusters_counter));
1473  	if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1474  		ext4_group_t flex_group;
1475  		struct flex_groups *fg;
1476  
1477  		flex_group = ext4_flex_group(sbi, group_data[0].group);
1478  		fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1479  		atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1480  			     &fg->free_clusters);
1481  		atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1482  			   &fg->free_inodes);
1483  	}
1484  
1485  	/*
1486  	 * Update the fs overhead information
1487  	 */
1488  	ext4_calculate_overhead(sb);
1489  	es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1490  
1491  	if (test_opt(sb, DEBUG))
1492  		printk(KERN_DEBUG "EXT4-fs: added group %u:"
1493  		       "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1494  		       blocks_count, free_blocks, reserved_blocks);
1495  }
1496  
1497  /* Add a flex group to an fs. Ensure we handle all possible error conditions
1498   * _before_ we start modifying the filesystem, because we cannot abort the
1499   * transaction and not have it write the data to disk.
1500   */
ext4_flex_group_add(struct super_block * sb,struct inode * resize_inode,struct ext4_new_flex_group_data * flex_gd)1501  static int ext4_flex_group_add(struct super_block *sb,
1502  			       struct inode *resize_inode,
1503  			       struct ext4_new_flex_group_data *flex_gd)
1504  {
1505  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1506  	struct ext4_super_block *es = sbi->s_es;
1507  	ext4_fsblk_t o_blocks_count;
1508  	ext4_grpblk_t last;
1509  	ext4_group_t group;
1510  	handle_t *handle;
1511  	unsigned reserved_gdb;
1512  	int err = 0, err2 = 0, credit;
1513  
1514  	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1515  
1516  	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1517  	o_blocks_count = ext4_blocks_count(es);
1518  	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1519  	BUG_ON(last);
1520  
1521  	err = setup_new_flex_group_blocks(sb, flex_gd);
1522  	if (err)
1523  		goto exit;
1524  	/*
1525  	 * We will always be modifying at least the superblock and  GDT
1526  	 * blocks.  If we are adding a group past the last current GDT block,
1527  	 * we will also modify the inode and the dindirect block.  If we
1528  	 * are adding a group with superblock/GDT backups  we will also
1529  	 * modify each of the reserved GDT dindirect blocks.
1530  	 */
1531  	credit = 3;	/* sb, resize inode, resize inode dindirect */
1532  	/* GDT blocks */
1533  	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1534  	credit += reserved_gdb;	/* Reserved GDT dindirect blocks */
1535  	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1536  	if (IS_ERR(handle)) {
1537  		err = PTR_ERR(handle);
1538  		goto exit;
1539  	}
1540  
1541  	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1542  	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1543  	if (err)
1544  		goto exit_journal;
1545  
1546  	group = flex_gd->groups[0].group;
1547  	BUG_ON(group != sbi->s_groups_count);
1548  	err = ext4_add_new_descs(handle, sb, group,
1549  				resize_inode, flex_gd->count);
1550  	if (err)
1551  		goto exit_journal;
1552  
1553  	err = ext4_setup_new_descs(handle, sb, flex_gd);
1554  	if (err)
1555  		goto exit_journal;
1556  
1557  	ext4_update_super(sb, flex_gd);
1558  
1559  	err = ext4_handle_dirty_super(handle, sb);
1560  
1561  exit_journal:
1562  	err2 = ext4_journal_stop(handle);
1563  	if (!err)
1564  		err = err2;
1565  
1566  	if (!err) {
1567  		int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1568  		int gdb_num_end = ((group + flex_gd->count - 1) /
1569  				   EXT4_DESC_PER_BLOCK(sb));
1570  		int meta_bg = ext4_has_feature_meta_bg(sb) &&
1571  			      gdb_num >= le32_to_cpu(es->s_first_meta_bg);
1572  		sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
1573  					 ext4_group_first_block_no(sb, 0);
1574  		sector_t old_gdb = 0;
1575  
1576  		update_backups(sb, ext4_group_first_block_no(sb, 0),
1577  			       (char *)es, sizeof(struct ext4_super_block), 0);
1578  		for (; gdb_num <= gdb_num_end; gdb_num++) {
1579  			struct buffer_head *gdb_bh;
1580  
1581  			gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1582  						     gdb_num);
1583  			if (old_gdb == gdb_bh->b_blocknr)
1584  				continue;
1585  			update_backups(sb, gdb_bh->b_blocknr - padding_blocks,
1586  				       gdb_bh->b_data, gdb_bh->b_size, meta_bg);
1587  			old_gdb = gdb_bh->b_blocknr;
1588  		}
1589  	}
1590  exit:
1591  	return err;
1592  }
1593  
ext4_setup_next_flex_gd(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd,ext4_fsblk_t n_blocks_count)1594  static int ext4_setup_next_flex_gd(struct super_block *sb,
1595  				    struct ext4_new_flex_group_data *flex_gd,
1596  				    ext4_fsblk_t n_blocks_count)
1597  {
1598  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1599  	struct ext4_super_block *es = sbi->s_es;
1600  	struct ext4_new_group_data *group_data = flex_gd->groups;
1601  	ext4_fsblk_t o_blocks_count;
1602  	ext4_group_t n_group;
1603  	ext4_group_t group;
1604  	ext4_group_t last_group;
1605  	ext4_grpblk_t last;
1606  	ext4_grpblk_t clusters_per_group;
1607  	unsigned long i;
1608  
1609  	clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1610  
1611  	o_blocks_count = ext4_blocks_count(es);
1612  
1613  	if (o_blocks_count == n_blocks_count)
1614  		return 0;
1615  
1616  	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1617  	BUG_ON(last);
1618  	ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1619  
1620  	last_group = group | (flex_gd->resize_bg - 1);
1621  	if (last_group > n_group)
1622  		last_group = n_group;
1623  
1624  	flex_gd->count = last_group - group + 1;
1625  
1626  	for (i = 0; i < flex_gd->count; i++) {
1627  		int overhead;
1628  
1629  		group_data[i].group = group + i;
1630  		group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1631  		overhead = ext4_group_overhead_blocks(sb, group + i);
1632  		group_data[i].mdata_blocks = overhead;
1633  		group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1634  		if (ext4_has_group_desc_csum(sb)) {
1635  			flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1636  					       EXT4_BG_INODE_UNINIT;
1637  			if (!test_opt(sb, INIT_INODE_TABLE))
1638  				flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1639  		} else
1640  			flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1641  	}
1642  
1643  	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1644  		/* We need to initialize block bitmap of last group. */
1645  		flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1646  
1647  	if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1648  		group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1649  		group_data[i - 1].free_clusters_count -= clusters_per_group -
1650  						       last - 1;
1651  	}
1652  
1653  	return 1;
1654  }
1655  
1656  /* Add group descriptor data to an existing or new group descriptor block.
1657   * Ensure we handle all possible error conditions _before_ we start modifying
1658   * the filesystem, because we cannot abort the transaction and not have it
1659   * write the data to disk.
1660   *
1661   * If we are on a GDT block boundary, we need to get the reserved GDT block.
1662   * Otherwise, we may need to add backup GDT blocks for a sparse group.
1663   *
1664   * We only need to hold the superblock lock while we are actually adding
1665   * in the new group's counts to the superblock.  Prior to that we have
1666   * not really "added" the group at all.  We re-check that we are still
1667   * adding in the last group in case things have changed since verifying.
1668   */
ext4_group_add(struct super_block * sb,struct ext4_new_group_data * input)1669  int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1670  {
1671  	struct ext4_new_flex_group_data flex_gd;
1672  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1673  	struct ext4_super_block *es = sbi->s_es;
1674  	int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1675  		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1676  	struct inode *inode = NULL;
1677  	int gdb_off;
1678  	int err;
1679  	__u16 bg_flags = 0;
1680  
1681  	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1682  
1683  	if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1684  		ext4_warning(sb, "Can't resize non-sparse filesystem further");
1685  		return -EPERM;
1686  	}
1687  
1688  	if (ext4_blocks_count(es) + input->blocks_count <
1689  	    ext4_blocks_count(es)) {
1690  		ext4_warning(sb, "blocks_count overflow");
1691  		return -EINVAL;
1692  	}
1693  
1694  	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1695  	    le32_to_cpu(es->s_inodes_count)) {
1696  		ext4_warning(sb, "inodes_count overflow");
1697  		return -EINVAL;
1698  	}
1699  
1700  	if (reserved_gdb || gdb_off == 0) {
1701  		if (!ext4_has_feature_resize_inode(sb) ||
1702  		    !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1703  			ext4_warning(sb,
1704  				     "No reserved GDT blocks, can't resize");
1705  			return -EPERM;
1706  		}
1707  		inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1708  		if (IS_ERR(inode)) {
1709  			ext4_warning(sb, "Error opening resize inode");
1710  			return PTR_ERR(inode);
1711  		}
1712  	}
1713  
1714  
1715  	err = verify_group_input(sb, input);
1716  	if (err)
1717  		goto out;
1718  
1719  	err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1720  	if (err)
1721  		goto out;
1722  
1723  	err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1724  	if (err)
1725  		goto out;
1726  
1727  	flex_gd.count = 1;
1728  	flex_gd.groups = input;
1729  	flex_gd.bg_flags = &bg_flags;
1730  	err = ext4_flex_group_add(sb, inode, &flex_gd);
1731  out:
1732  	iput(inode);
1733  	return err;
1734  } /* ext4_group_add */
1735  
1736  /*
1737   * extend a group without checking assuming that checking has been done.
1738   */
ext4_group_extend_no_check(struct super_block * sb,ext4_fsblk_t o_blocks_count,ext4_grpblk_t add)1739  static int ext4_group_extend_no_check(struct super_block *sb,
1740  				      ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1741  {
1742  	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1743  	handle_t *handle;
1744  	int err = 0, err2;
1745  
1746  	/* We will update the superblock, one block bitmap, and
1747  	 * one group descriptor via ext4_group_add_blocks().
1748  	 */
1749  	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1750  	if (IS_ERR(handle)) {
1751  		err = PTR_ERR(handle);
1752  		ext4_warning(sb, "error %d on journal start", err);
1753  		return err;
1754  	}
1755  
1756  	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1757  	err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1758  	if (err) {
1759  		ext4_warning(sb, "error %d on journal write access", err);
1760  		goto errout;
1761  	}
1762  
1763  	ext4_blocks_count_set(es, o_blocks_count + add);
1764  	ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1765  	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1766  		   o_blocks_count + add);
1767  	/* We add the blocks to the bitmap and set the group need init bit */
1768  	err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1769  	if (err)
1770  		goto errout;
1771  	ext4_handle_dirty_super(handle, sb);
1772  	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1773  		   o_blocks_count + add);
1774  errout:
1775  	err2 = ext4_journal_stop(handle);
1776  	if (err2 && !err)
1777  		err = err2;
1778  
1779  	if (!err) {
1780  		if (test_opt(sb, DEBUG))
1781  			printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1782  			       "blocks\n", ext4_blocks_count(es));
1783  		update_backups(sb, ext4_group_first_block_no(sb, 0),
1784  			       (char *)es, sizeof(struct ext4_super_block), 0);
1785  	}
1786  	return err;
1787  }
1788  
1789  /*
1790   * Extend the filesystem to the new number of blocks specified.  This entry
1791   * point is only used to extend the current filesystem to the end of the last
1792   * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
1793   * for emergencies (because it has no dependencies on reserved blocks).
1794   *
1795   * If we _really_ wanted, we could use default values to call ext4_group_add()
1796   * allow the "remount" trick to work for arbitrary resizing, assuming enough
1797   * GDT blocks are reserved to grow to the desired size.
1798   */
ext4_group_extend(struct super_block * sb,struct ext4_super_block * es,ext4_fsblk_t n_blocks_count)1799  int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1800  		      ext4_fsblk_t n_blocks_count)
1801  {
1802  	ext4_fsblk_t o_blocks_count;
1803  	ext4_grpblk_t last;
1804  	ext4_grpblk_t add;
1805  	struct buffer_head *bh;
1806  	int err;
1807  	ext4_group_t group;
1808  
1809  	o_blocks_count = ext4_blocks_count(es);
1810  
1811  	if (test_opt(sb, DEBUG))
1812  		ext4_msg(sb, KERN_DEBUG,
1813  			 "extending last group from %llu to %llu blocks",
1814  			 o_blocks_count, n_blocks_count);
1815  
1816  	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1817  		return 0;
1818  
1819  	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1820  		ext4_msg(sb, KERN_ERR,
1821  			 "filesystem too large to resize to %llu blocks safely",
1822  			 n_blocks_count);
1823  		return -EINVAL;
1824  	}
1825  
1826  	if (n_blocks_count < o_blocks_count) {
1827  		ext4_warning(sb, "can't shrink FS - resize aborted");
1828  		return -EINVAL;
1829  	}
1830  
1831  	/* Handle the remaining blocks in the last group only. */
1832  	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1833  
1834  	if (last == 0) {
1835  		ext4_warning(sb, "need to use ext2online to resize further");
1836  		return -EPERM;
1837  	}
1838  
1839  	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1840  
1841  	if (o_blocks_count + add < o_blocks_count) {
1842  		ext4_warning(sb, "blocks_count overflow");
1843  		return -EINVAL;
1844  	}
1845  
1846  	if (o_blocks_count + add > n_blocks_count)
1847  		add = n_blocks_count - o_blocks_count;
1848  
1849  	if (o_blocks_count + add < n_blocks_count)
1850  		ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1851  			     o_blocks_count + add, add);
1852  
1853  	/* See if the device is actually as big as what was requested */
1854  	bh = sb_bread(sb, o_blocks_count + add - 1);
1855  	if (!bh) {
1856  		ext4_warning(sb, "can't read last block, resize aborted");
1857  		return -ENOSPC;
1858  	}
1859  	brelse(bh);
1860  
1861  	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1862  	return err;
1863  } /* ext4_group_extend */
1864  
1865  
num_desc_blocks(struct super_block * sb,ext4_group_t groups)1866  static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1867  {
1868  	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1869  }
1870  
1871  /*
1872   * Release the resize inode and drop the resize_inode feature if there
1873   * are no more reserved gdt blocks, and then convert the file system
1874   * to enable meta_bg
1875   */
ext4_convert_meta_bg(struct super_block * sb,struct inode * inode)1876  static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1877  {
1878  	handle_t *handle;
1879  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1880  	struct ext4_super_block *es = sbi->s_es;
1881  	struct ext4_inode_info *ei = EXT4_I(inode);
1882  	ext4_fsblk_t nr;
1883  	int i, ret, err = 0;
1884  	int credits = 1;
1885  
1886  	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1887  	if (inode) {
1888  		if (es->s_reserved_gdt_blocks) {
1889  			ext4_error(sb, "Unexpected non-zero "
1890  				   "s_reserved_gdt_blocks");
1891  			return -EPERM;
1892  		}
1893  
1894  		/* Do a quick sanity check of the resize inode */
1895  		if (inode->i_blocks != 1 << (inode->i_blkbits -
1896  					     (9 - sbi->s_cluster_bits)))
1897  			goto invalid_resize_inode;
1898  		for (i = 0; i < EXT4_N_BLOCKS; i++) {
1899  			if (i == EXT4_DIND_BLOCK) {
1900  				if (ei->i_data[i])
1901  					continue;
1902  				else
1903  					goto invalid_resize_inode;
1904  			}
1905  			if (ei->i_data[i])
1906  				goto invalid_resize_inode;
1907  		}
1908  		credits += 3;	/* block bitmap, bg descriptor, resize inode */
1909  	}
1910  
1911  	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1912  	if (IS_ERR(handle))
1913  		return PTR_ERR(handle);
1914  
1915  	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1916  	err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1917  	if (err)
1918  		goto errout;
1919  
1920  	ext4_clear_feature_resize_inode(sb);
1921  	ext4_set_feature_meta_bg(sb);
1922  	sbi->s_es->s_first_meta_bg =
1923  		cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1924  
1925  	err = ext4_handle_dirty_super(handle, sb);
1926  	if (err) {
1927  		ext4_std_error(sb, err);
1928  		goto errout;
1929  	}
1930  
1931  	if (inode) {
1932  		nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1933  		ext4_free_blocks(handle, inode, NULL, nr, 1,
1934  				 EXT4_FREE_BLOCKS_METADATA |
1935  				 EXT4_FREE_BLOCKS_FORGET);
1936  		ei->i_data[EXT4_DIND_BLOCK] = 0;
1937  		inode->i_blocks = 0;
1938  
1939  		err = ext4_mark_inode_dirty(handle, inode);
1940  		if (err)
1941  			ext4_std_error(sb, err);
1942  	}
1943  
1944  errout:
1945  	ret = ext4_journal_stop(handle);
1946  	return err ? err : ret;
1947  
1948  invalid_resize_inode:
1949  	ext4_error(sb, "corrupted/inconsistent resize inode");
1950  	return -EINVAL;
1951  }
1952  
1953  /*
1954   * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1955   *
1956   * @sb: super block of the fs to be resized
1957   * @n_blocks_count: the number of blocks resides in the resized fs
1958   */
ext4_resize_fs(struct super_block * sb,ext4_fsblk_t n_blocks_count)1959  int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1960  {
1961  	struct ext4_new_flex_group_data *flex_gd = NULL;
1962  	struct ext4_sb_info *sbi = EXT4_SB(sb);
1963  	struct ext4_super_block *es = sbi->s_es;
1964  	struct buffer_head *bh;
1965  	struct inode *resize_inode = NULL;
1966  	ext4_grpblk_t add, offset;
1967  	unsigned long n_desc_blocks;
1968  	unsigned long o_desc_blocks;
1969  	ext4_group_t o_group;
1970  	ext4_group_t n_group;
1971  	ext4_fsblk_t o_blocks_count;
1972  	ext4_fsblk_t n_blocks_count_retry = 0;
1973  	unsigned long last_update_time = 0;
1974  	int err = 0;
1975  	int meta_bg;
1976  	unsigned int flexbg_size = ext4_flex_bg_size(sbi);
1977  
1978  	/* See if the device is actually as big as what was requested */
1979  	bh = sb_bread(sb, n_blocks_count - 1);
1980  	if (!bh) {
1981  		ext4_warning(sb, "can't read last block, resize aborted");
1982  		return -ENOSPC;
1983  	}
1984  	brelse(bh);
1985  
1986  	/*
1987  	 * For bigalloc, trim the requested size to the nearest cluster
1988  	 * boundary to avoid creating an unusable filesystem. We do this
1989  	 * silently, instead of returning an error, to avoid breaking
1990  	 * callers that blindly resize the filesystem to the full size of
1991  	 * the underlying block device.
1992  	 */
1993  	if (ext4_has_feature_bigalloc(sb))
1994  		n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
1995  
1996  retry:
1997  	o_blocks_count = ext4_blocks_count(es);
1998  
1999  	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
2000  		 "to %llu blocks", o_blocks_count, n_blocks_count);
2001  
2002  	if (n_blocks_count < o_blocks_count) {
2003  		/* On-line shrinking not supported */
2004  		ext4_warning(sb, "can't shrink FS - resize aborted");
2005  		return -EINVAL;
2006  	}
2007  
2008  	if (n_blocks_count == o_blocks_count)
2009  		/* Nothing need to do */
2010  		return 0;
2011  
2012  	n_group = ext4_get_group_number(sb, n_blocks_count - 1);
2013  	if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2014  		ext4_warning(sb, "resize would cause inodes_count overflow");
2015  		return -EINVAL;
2016  	}
2017  	ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
2018  
2019  	n_desc_blocks = num_desc_blocks(sb, n_group + 1);
2020  	o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
2021  
2022  	meta_bg = ext4_has_feature_meta_bg(sb);
2023  
2024  	if (ext4_has_feature_resize_inode(sb)) {
2025  		if (meta_bg) {
2026  			ext4_error(sb, "resize_inode and meta_bg enabled "
2027  				   "simultaneously");
2028  			return -EINVAL;
2029  		}
2030  		if (n_desc_blocks > o_desc_blocks +
2031  		    le16_to_cpu(es->s_reserved_gdt_blocks)) {
2032  			n_blocks_count_retry = n_blocks_count;
2033  			n_desc_blocks = o_desc_blocks +
2034  				le16_to_cpu(es->s_reserved_gdt_blocks);
2035  			n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2036  			n_blocks_count = (ext4_fsblk_t)n_group *
2037  				EXT4_BLOCKS_PER_GROUP(sb) +
2038  				le32_to_cpu(es->s_first_data_block);
2039  			n_group--; /* set to last group number */
2040  		}
2041  
2042  		if (!resize_inode)
2043  			resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2044  						 EXT4_IGET_SPECIAL);
2045  		if (IS_ERR(resize_inode)) {
2046  			ext4_warning(sb, "Error opening resize inode");
2047  			return PTR_ERR(resize_inode);
2048  		}
2049  	}
2050  
2051  	if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2052  		err = ext4_convert_meta_bg(sb, resize_inode);
2053  		if (err)
2054  			goto out;
2055  		if (resize_inode) {
2056  			iput(resize_inode);
2057  			resize_inode = NULL;
2058  		}
2059  		if (n_blocks_count_retry) {
2060  			n_blocks_count = n_blocks_count_retry;
2061  			n_blocks_count_retry = 0;
2062  			goto retry;
2063  		}
2064  	}
2065  
2066  	/*
2067  	 * Make sure the last group has enough space so that it's
2068  	 * guaranteed to have enough space for all metadata blocks
2069  	 * that it might need to hold.  (We might not need to store
2070  	 * the inode table blocks in the last block group, but there
2071  	 * will be cases where this might be needed.)
2072  	 */
2073  	if ((ext4_group_first_block_no(sb, n_group) +
2074  	     ext4_group_overhead_blocks(sb, n_group) + 2 +
2075  	     sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2076  		n_blocks_count = ext4_group_first_block_no(sb, n_group);
2077  		n_group--;
2078  		n_blocks_count_retry = 0;
2079  		if (resize_inode) {
2080  			iput(resize_inode);
2081  			resize_inode = NULL;
2082  		}
2083  		goto retry;
2084  	}
2085  
2086  	/* extend the last group */
2087  	if (n_group == o_group)
2088  		add = n_blocks_count - o_blocks_count;
2089  	else
2090  		add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2091  	if (add > 0) {
2092  		err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2093  		if (err)
2094  			goto out;
2095  	}
2096  
2097  	if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2098  		goto out;
2099  
2100  	err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2101  	if (err)
2102  		goto out;
2103  
2104  	err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2105  	if (err)
2106  		goto out;
2107  
2108  	flex_gd = alloc_flex_gd(flexbg_size);
2109  	if (flex_gd == NULL) {
2110  		err = -ENOMEM;
2111  		goto out;
2112  	}
2113  
2114  	/* Add flex groups. Note that a regular group is a
2115  	 * flex group with 1 group.
2116  	 */
2117  	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count)) {
2118  		if (jiffies - last_update_time > HZ * 10) {
2119  			if (last_update_time)
2120  				ext4_msg(sb, KERN_INFO,
2121  					 "resized to %llu blocks",
2122  					 ext4_blocks_count(es));
2123  			last_update_time = jiffies;
2124  		}
2125  		if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2126  			break;
2127  		err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2128  		if (unlikely(err))
2129  			break;
2130  	}
2131  
2132  	if (!err && n_blocks_count_retry) {
2133  		n_blocks_count = n_blocks_count_retry;
2134  		n_blocks_count_retry = 0;
2135  		free_flex_gd(flex_gd);
2136  		flex_gd = NULL;
2137  		if (resize_inode) {
2138  			iput(resize_inode);
2139  			resize_inode = NULL;
2140  		}
2141  		goto retry;
2142  	}
2143  
2144  out:
2145  	if (flex_gd)
2146  		free_flex_gd(flex_gd);
2147  	if (resize_inode != NULL)
2148  		iput(resize_inode);
2149  	if (err)
2150  		ext4_warning(sb, "error (%d) occurred during "
2151  			     "file system resize", err);
2152  	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2153  		 ext4_blocks_count(es));
2154  	return err;
2155  }
2156