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Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/balloc.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
10 * Big-endian to little-endian byte-swapping/bitmaps by
11 * David S. Miller (davem@caip.rutgers.edu), 1995
12 */
13
14#include <linux/time.h>
15#include <linux/capability.h>
16#include <linux/fs.h>
Mingming Caodab291a2006-10-11 01:21:01 -070017#include <linux/jbd2.h>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070018#include <linux/quotaops.h>
19#include <linux/buffer_head.h>
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040020#include "ext4.h"
21#include "ext4_jbd2.h"
Aneesh Kumar K.Ve21675d2009-01-05 21:36:02 -050022#include "mballoc.h"
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040023
Jiaying Zhang0562e0b2011-03-21 21:38:05 -040024#include <trace/events/ext4.h>
25
Dave Kleikampac27a0e2006-10-11 01:20:50 -070026/*
27 * balloc.c contains the blocks allocation and deallocation routines
28 */
29
30/*
Theodore Ts'o3212a802011-09-09 18:46:51 -040031 * Calculate the block group number and offset into the block/cluster
32 * allocation bitmap, given a block number
Andrew Morton72b64b52006-10-11 01:21:18 -070033 */
34void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
Avantika Mathurfd2d4292008-01-28 23:58:27 -050035 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
Andrew Morton72b64b52006-10-11 01:21:18 -070036{
Dave Kleikamp8c55e202007-05-24 13:04:54 -040037 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
Andrew Morton72b64b52006-10-11 01:21:18 -070038 ext4_grpblk_t offset;
39
Dave Kleikamp8c55e202007-05-24 13:04:54 -040040 blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
Theodore Ts'o3212a802011-09-09 18:46:51 -040041 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
42 EXT4_SB(sb)->s_cluster_bits;
Andrew Morton72b64b52006-10-11 01:21:18 -070043 if (offsetp)
44 *offsetp = offset;
45 if (blockgrpp)
Dave Kleikamp8c55e202007-05-24 13:04:54 -040046 *blockgrpp = blocknr;
Andrew Morton72b64b52006-10-11 01:21:18 -070047
48}
49
Jose R. Santos0bf7e832008-06-03 14:07:29 -040050static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
51 ext4_group_t block_group)
52{
53 ext4_group_t actual_group;
Aneesh Kumar K.V74778272008-07-11 19:27:31 -040054 ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
Jose R. Santos0bf7e832008-06-03 14:07:29 -040055 if (actual_group == block_group)
56 return 1;
57 return 0;
58}
59
Theodore Ts'od5b8f312011-09-09 18:44:51 -040060/* Return the number of clusters used for file system metadata; this
61 * represents the overhead needed by the file system.
62 */
63unsigned ext4_num_overhead_clusters(struct super_block *sb,
64 ext4_group_t block_group,
65 struct ext4_group_desc *gdp)
Jose R. Santos0bf7e832008-06-03 14:07:29 -040066{
Theodore Ts'od5b8f312011-09-09 18:44:51 -040067 unsigned num_clusters;
68 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
69 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
70 ext4_fsblk_t itbl_blk;
Jose R. Santos0bf7e832008-06-03 14:07:29 -040071 struct ext4_sb_info *sbi = EXT4_SB(sb);
Jose R. Santos0bf7e832008-06-03 14:07:29 -040072
Theodore Ts'od5b8f312011-09-09 18:44:51 -040073 /* This is the number of clusters used by the superblock,
74 * block group descriptors, and reserved block group
75 * descriptor blocks */
76 num_clusters = ext4_num_base_meta_clusters(sb, block_group);
Jose R. Santos0bf7e832008-06-03 14:07:29 -040077
Theodore Ts'od5b8f312011-09-09 18:44:51 -040078 /*
79 * For the allocation bitmaps and inode table, we first need
80 * to check to see if the block is in the block group. If it
81 * is, then check to see if the cluster is already accounted
82 * for in the clusters used for the base metadata cluster, or
83 * if we can increment the base metadata cluster to include
84 * that block. Otherwise, we will have to track the cluster
85 * used for the allocation bitmap or inode table explicitly.
86 * Normally all of these blocks are contiguous, so the special
87 * case handling shouldn't be necessary except for *very*
88 * unusual file system layouts.
89 */
90 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
91 block_cluster = EXT4_B2C(sbi, (start -
92 ext4_block_bitmap(sb, gdp)));
93 if (block_cluster < num_clusters)
94 block_cluster = -1;
95 else if (block_cluster == num_clusters) {
96 num_clusters++;
97 block_cluster = -1;
Jose R. Santos0bf7e832008-06-03 14:07:29 -040098 }
99 }
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400100
101 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
102 inode_cluster = EXT4_B2C(sbi,
103 start - ext4_inode_bitmap(sb, gdp));
104 if (inode_cluster < num_clusters)
105 inode_cluster = -1;
106 else if (inode_cluster == num_clusters) {
107 num_clusters++;
108 inode_cluster = -1;
109 }
110 }
111
112 itbl_blk = ext4_inode_table(sb, gdp);
113 for (i = 0; i < sbi->s_itb_per_group; i++) {
114 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
115 c = EXT4_B2C(sbi, start - itbl_blk + i);
116 if ((c < num_clusters) || (c == inode_cluster) ||
117 (c == block_cluster) || (c == itbl_cluster))
118 continue;
119 if (c == num_clusters) {
120 num_clusters++;
121 continue;
122 }
123 num_clusters++;
124 itbl_cluster = c;
125 }
126 }
127
128 if (block_cluster != -1)
129 num_clusters++;
130 if (inode_cluster != -1)
131 num_clusters++;
132
133 return num_clusters;
Jose R. Santos0bf7e832008-06-03 14:07:29 -0400134}
Theodore Ts'oc2ea3fd2008-10-10 09:40:52 -0400135
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400136static unsigned int num_clusters_in_group(struct super_block *sb,
137 ext4_group_t block_group)
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400138{
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400139 unsigned int blocks;
140
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400141 if (block_group == ext4_get_groups_count(sb) - 1) {
142 /*
143 * Even though mke2fs always initializes the first and
144 * last group, just in case some other tool was used,
145 * we need to make sure we calculate the right free
146 * blocks.
147 */
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400148 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400149 ext4_group_first_block_no(sb, block_group);
150 } else
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400151 blocks = EXT4_BLOCKS_PER_GROUP(sb);
152 return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400153}
154
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400155/* Initializes an uninitialized block bitmap */
156void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
157 ext4_group_t block_group,
158 struct ext4_group_desc *gdp)
Andreas Dilger717d50e2007-10-16 18:38:25 -0400159{
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400160 unsigned int bit, bit_max;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400161 struct ext4_sb_info *sbi = EXT4_SB(sb);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400162 ext4_fsblk_t start, tmp;
163 int flex_bg = 0;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400164
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400165 J_ASSERT_BH(bh, buffer_locked(bh));
Andreas Dilger717d50e2007-10-16 18:38:25 -0400166
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400167 /* If checksum is bad mark all blocks used to prevent allocation
168 * essentially implementing a per-group read-only flag. */
169 if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
170 ext4_error(sb, "Checksum bad for group %u", block_group);
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400171 ext4_free_group_clusters_set(sb, gdp, 0);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400172 ext4_free_inodes_set(sb, gdp, 0);
173 ext4_itable_unused_set(sb, gdp, 0);
174 memset(bh->b_data, 0xff, sb->s_blocksize);
175 return;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400176 }
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400177 memset(bh->b_data, 0, sb->s_blocksize);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400178
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400179 bit_max = ext4_num_base_meta_clusters(sb, block_group);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400180 for (bit = 0; bit < bit_max; bit++)
181 ext4_set_bit(bit, bh->b_data);
Akinobu Mitad00a6d72008-04-17 10:38:59 -0400182
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400183 start = ext4_group_first_block_no(sb, block_group);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400184
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400185 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
186 flex_bg = 1;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400187
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400188 /* Set bits for block and inode bitmaps, and inode table */
189 tmp = ext4_block_bitmap(sb, gdp);
190 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400191 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400192
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400193 tmp = ext4_inode_bitmap(sb, gdp);
194 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400195 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400196
197 tmp = ext4_inode_table(sb, gdp);
198 for (; tmp < ext4_inode_table(sb, gdp) +
199 sbi->s_itb_per_group; tmp++) {
Jose R. Santos0bf7e832008-06-03 14:07:29 -0400200 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400201 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400202 }
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400203
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400204 /*
205 * Also if the number of blocks within the group is less than
206 * the blocksize * 8 ( which is the size of bitmap ), set rest
207 * of the block bitmap to 1
208 */
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400209 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400210 sb->s_blocksize * 8, bh->b_data);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400211}
212
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400213/* Return the number of free blocks in a block group. It is used when
214 * the block bitmap is uninitialized, so we can't just count the bits
215 * in the bitmap. */
Theodore Ts'ocff1dfd72011-09-09 19:12:51 -0400216unsigned ext4_free_clusters_after_init(struct super_block *sb,
217 ext4_group_t block_group,
218 struct ext4_group_desc *gdp)
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400219{
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400220 return num_clusters_in_group(sb, block_group) -
221 ext4_num_overhead_clusters(sb, block_group, gdp);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400222}
Andreas Dilger717d50e2007-10-16 18:38:25 -0400223
Andrew Morton72b64b52006-10-11 01:21:18 -0700224/*
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700225 * The free blocks are managed by bitmaps. A file system contains several
226 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
227 * block for inodes, N blocks for the inode table and data blocks.
228 *
229 * The file system contains group descriptors which are located after the
230 * super block. Each descriptor contains the number of the bitmap block and
231 * the free blocks count in the block. The descriptors are loaded in memory
Aneesh Kumar K.Ve6274322007-02-20 13:57:58 -0800232 * when a file system is mounted (see ext4_fill_super).
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700233 */
234
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700235/**
Mingming Cao617ba132006-10-11 01:20:53 -0700236 * ext4_get_group_desc() -- load group descriptor from disk
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700237 * @sb: super block
238 * @block_group: given block group
239 * @bh: pointer to the buffer head to store the block
240 * group descriptor
241 */
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400242struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500243 ext4_group_t block_group,
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400244 struct buffer_head **bh)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700245{
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500246 unsigned int group_desc;
247 unsigned int offset;
Theodore Ts'o8df96752009-05-01 08:50:38 -0400248 ext4_group_t ngroups = ext4_get_groups_count(sb);
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400249 struct ext4_group_desc *desc;
Mingming Cao617ba132006-10-11 01:20:53 -0700250 struct ext4_sb_info *sbi = EXT4_SB(sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700251
Theodore Ts'o8df96752009-05-01 08:50:38 -0400252 if (block_group >= ngroups) {
Eric Sandeen12062dd2010-02-15 14:19:27 -0500253 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
254 " groups_count = %u", block_group, ngroups);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700255
256 return NULL;
257 }
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700258
Mingming Cao617ba132006-10-11 01:20:53 -0700259 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
260 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700261 if (!sbi->s_group_desc[group_desc]) {
Eric Sandeen12062dd2010-02-15 14:19:27 -0500262 ext4_error(sb, "Group descriptor not loaded - "
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500263 "block_group = %u, group_desc = %u, desc = %u",
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400264 block_group, group_desc, offset);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700265 return NULL;
266 }
267
Alexandre Ratchov0d1ee422006-10-11 01:21:14 -0700268 desc = (struct ext4_group_desc *)(
269 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
270 offset * EXT4_DESC_SIZE(sb));
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700271 if (bh)
272 *bh = sbi->s_group_desc[group_desc];
Alexandre Ratchov0d1ee422006-10-11 01:21:14 -0700273 return desc;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700274}
275
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500276static int ext4_valid_block_bitmap(struct super_block *sb,
277 struct ext4_group_desc *desc,
278 unsigned int block_group,
279 struct buffer_head *bh)
280{
281 ext4_grpblk_t offset;
282 ext4_grpblk_t next_zero_bit;
283 ext4_fsblk_t bitmap_blk;
284 ext4_fsblk_t group_first_block;
285
286 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
287 /* with FLEX_BG, the inode/block bitmaps and itable
288 * blocks may not be in the group at all
289 * so the bitmap validation will be skipped for those groups
290 * or it has to also read the block group where the bitmaps
291 * are located to verify they are set.
292 */
293 return 1;
294 }
295 group_first_block = ext4_group_first_block_no(sb, block_group);
296
297 /* check whether block bitmap block number is set */
298 bitmap_blk = ext4_block_bitmap(sb, desc);
299 offset = bitmap_blk - group_first_block;
300 if (!ext4_test_bit(offset, bh->b_data))
301 /* bad block bitmap */
302 goto err_out;
303
304 /* check whether the inode bitmap block number is set */
305 bitmap_blk = ext4_inode_bitmap(sb, desc);
306 offset = bitmap_blk - group_first_block;
307 if (!ext4_test_bit(offset, bh->b_data))
308 /* bad block bitmap */
309 goto err_out;
310
311 /* check whether the inode table block number is set */
312 bitmap_blk = ext4_inode_table(sb, desc);
313 offset = bitmap_blk - group_first_block;
314 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
315 offset + EXT4_SB(sb)->s_itb_per_group,
316 offset);
317 if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group)
318 /* good bitmap for inode tables */
319 return 1;
320
321err_out:
Eric Sandeen12062dd2010-02-15 14:19:27 -0500322 ext4_error(sb, "Invalid block bitmap - block_group = %d, block = %llu",
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500323 block_group, bitmap_blk);
324 return 0;
325}
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700326/**
Theodore Ts'o574ca172008-07-11 19:27:31 -0400327 * ext4_read_block_bitmap()
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700328 * @sb: super block
329 * @block_group: given block group
330 *
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500331 * Read the bitmap for a given block_group,and validate the
332 * bits for block/inode/inode tables are set in the bitmaps
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700333 *
334 * Return buffer_head on success or NULL in case of failure.
335 */
Andreas Dilger717d50e2007-10-16 18:38:25 -0400336struct buffer_head *
Theodore Ts'o574ca172008-07-11 19:27:31 -0400337ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700338{
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400339 struct ext4_group_desc *desc;
340 struct buffer_head *bh = NULL;
Aneesh Kumar K.V7c9e69f2007-10-16 23:27:02 -0700341 ext4_fsblk_t bitmap_blk;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700342
Andreas Dilger717d50e2007-10-16 18:38:25 -0400343 desc = ext4_get_group_desc(sb, block_group, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700344 if (!desc)
Aneesh Kumar K.V7c9e69f2007-10-16 23:27:02 -0700345 return NULL;
346 bitmap_blk = ext4_block_bitmap(sb, desc);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500347 bh = sb_getblk(sb, bitmap_blk);
348 if (unlikely(!bh)) {
Eric Sandeen12062dd2010-02-15 14:19:27 -0500349 ext4_error(sb, "Cannot read block bitmap - "
Theodore Ts'oa9df9a42009-01-05 22:18:16 -0500350 "block_group = %u, block_bitmap = %llu",
Eric Sandeene29d1cd2008-08-02 21:21:02 -0400351 block_group, bitmap_blk);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500352 return NULL;
353 }
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500354
355 if (bitmap_uptodate(bh))
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500356 return bh;
357
Frederic Bohec806e682008-10-10 08:09:18 -0400358 lock_buffer(bh);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500359 if (bitmap_uptodate(bh)) {
360 unlock_buffer(bh);
361 return bh;
362 }
Aneesh Kumar K.V955ce5f2009-05-02 20:35:09 -0400363 ext4_lock_group(sb, block_group);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500364 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
365 ext4_init_block_bitmap(sb, bh, block_group, desc);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500366 set_bitmap_uptodate(bh);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500367 set_buffer_uptodate(bh);
Aneesh Kumar K.V955ce5f2009-05-02 20:35:09 -0400368 ext4_unlock_group(sb, block_group);
Aneesh Kumar K.V3300bed2009-01-03 22:33:39 -0500369 unlock_buffer(bh);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500370 return bh;
371 }
Aneesh Kumar K.V955ce5f2009-05-02 20:35:09 -0400372 ext4_unlock_group(sb, block_group);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500373 if (buffer_uptodate(bh)) {
374 /*
375 * if not uninit if bh is uptodate,
376 * bitmap is also uptodate
377 */
378 set_bitmap_uptodate(bh);
379 unlock_buffer(bh);
380 return bh;
381 }
382 /*
383 * submit the buffer_head for read. We can
384 * safely mark the bitmap as uptodate now.
385 * We do it here so the bitmap uptodate bit
386 * get set with buffer lock held.
387 */
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400388 trace_ext4_read_block_bitmap_load(sb, block_group);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500389 set_bitmap_uptodate(bh);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500390 if (bh_submit_read(bh) < 0) {
391 put_bh(bh);
Eric Sandeen12062dd2010-02-15 14:19:27 -0500392 ext4_error(sb, "Cannot read block bitmap - "
Theodore Ts'oa9df9a42009-01-05 22:18:16 -0500393 "block_group = %u, block_bitmap = %llu",
Eric Sandeene29d1cd2008-08-02 21:21:02 -0400394 block_group, bitmap_blk);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500395 return NULL;
396 }
Aneesh Kumar K.V519deca2008-05-15 14:43:20 -0400397 ext4_valid_block_bitmap(sb, desc, block_group, bh);
398 /*
399 * file system mounted not to panic on error,
400 * continue with corrupt bitmap
401 */
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700402 return bh;
403}
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700404
405/**
Theodore Ts'odf55c992011-09-09 19:16:51 -0400406 * ext4_has_free_clusters()
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400407 * @sbi: in-core super block structure.
Theodore Ts'odf55c992011-09-09 19:16:51 -0400408 * @nclusters: number of needed blocks
409 * @flags: flags from ext4_mb_new_blocks()
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400410 *
Theodore Ts'odf55c992011-09-09 19:16:51 -0400411 * Check if filesystem has nclusters free & available for allocation.
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400412 * On success return 1, return 0 on failure.
413 */
Theodore Ts'odf55c992011-09-09 19:16:51 -0400414static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
415 s64 nclusters, unsigned int flags)
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400416{
Theodore Ts'odf55c992011-09-09 19:16:51 -0400417 s64 free_clusters, dirty_clusters, root_clusters;
Theodore Ts'o57042652011-09-09 18:56:51 -0400418 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
Theodore Ts'odf55c992011-09-09 19:16:51 -0400419 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400420
Theodore Ts'odf55c992011-09-09 19:16:51 -0400421 free_clusters = percpu_counter_read_positive(fcc);
422 dirty_clusters = percpu_counter_read_positive(dcc);
423 root_clusters = EXT4_B2C(sbi, ext4_r_blocks_count(sbi->s_es));
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400424
Theodore Ts'odf55c992011-09-09 19:16:51 -0400425 if (free_clusters - (nclusters + root_clusters + dirty_clusters) <
426 EXT4_FREECLUSTERS_WATERMARK) {
427 free_clusters = EXT4_C2B(sbi, percpu_counter_sum_positive(fcc));
428 dirty_clusters = percpu_counter_sum_positive(dcc);
Aneesh Kumar K.V6bc6e632008-10-10 09:39:00 -0400429 }
Theodore Ts'odf55c992011-09-09 19:16:51 -0400430 /* Check whether we have space after accounting for current
431 * dirty clusters & root reserved clusters.
Aneesh Kumar K.V6bc6e632008-10-10 09:39:00 -0400432 */
Theodore Ts'odf55c992011-09-09 19:16:51 -0400433 if (free_clusters >= ((root_clusters + nclusters) + dirty_clusters))
Eric Sandeena9960312008-10-28 00:08:17 -0400434 return 1;
Aneesh Kumar K.V5c791612008-10-08 23:12:24 -0400435
Theodore Ts'odf55c992011-09-09 19:16:51 -0400436 /* Hm, nope. Are (enough) root reserved clusters available? */
David Howells4c9c5442008-11-14 10:38:51 +1100437 if (sbi->s_resuid == current_fsuid() ||
Eric Sandeena9960312008-10-28 00:08:17 -0400438 ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) ||
Allison Henderson55f020d2011-05-25 07:41:26 -0400439 capable(CAP_SYS_RESOURCE) ||
440 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
441
Theodore Ts'odf55c992011-09-09 19:16:51 -0400442 if (free_clusters >= (nclusters + dirty_clusters))
Eric Sandeena9960312008-10-28 00:08:17 -0400443 return 1;
444 }
445
446 return 0;
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400447}
Mingming Cao07031432008-07-11 19:27:31 -0400448
Theodore Ts'oe7d5f312011-09-09 19:14:51 -0400449int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
450 s64 nclusters, unsigned int flags)
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400451{
Theodore Ts'odf55c992011-09-09 19:16:51 -0400452 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
Theodore Ts'oe7d5f312011-09-09 19:14:51 -0400453 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400454 return 0;
455 } else
456 return -ENOSPC;
457}
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700458
459/**
Mingming Cao617ba132006-10-11 01:20:53 -0700460 * ext4_should_retry_alloc()
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700461 * @sb: super block
462 * @retries number of attemps has been made
463 *
Mingming Cao617ba132006-10-11 01:20:53 -0700464 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700465 * it is profitable to retry the operation, this function will wait
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300466 * for the current or committing transaction to complete, and then
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700467 * return TRUE.
468 *
469 * if the total number of retries exceed three times, return FALSE.
470 */
Mingming Cao617ba132006-10-11 01:20:53 -0700471int ext4_should_retry_alloc(struct super_block *sb, int *retries)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700472{
Theodore Ts'odf55c992011-09-09 19:16:51 -0400473 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
Eric Sandeen8f64b322009-02-26 00:57:35 -0500474 (*retries)++ > 3 ||
475 !EXT4_SB(sb)->s_journal)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700476 return 0;
477
478 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
479
Mingming Caodab291a2006-10-11 01:21:01 -0700480 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700481}
482
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400483/*
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400484 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
485 *
486 * @handle: handle to this transaction
487 * @inode: file inode
488 * @goal: given target block(filesystem wide)
Aditya Kali7b415bf2011-09-09 19:04:51 -0400489 * @count: pointer to total number of clusters needed
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400490 * @errp: error code
491 *
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500492 * Return 1st allocated block number on success, *count stores total account
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400493 * error stores in errp pointer
494 */
495ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
Allison Henderson55f020d2011-05-25 07:41:26 -0400496 ext4_fsblk_t goal, unsigned int flags,
497 unsigned long *count, int *errp)
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400498{
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500499 struct ext4_allocation_request ar;
Mingming Caod2a17632008-07-14 17:52:37 -0400500 ext4_fsblk_t ret;
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500501
502 memset(&ar, 0, sizeof(ar));
503 /* Fill with neighbour allocated blocks */
504 ar.inode = inode;
505 ar.goal = goal;
506 ar.len = count ? *count : 1;
Allison Henderson55f020d2011-05-25 07:41:26 -0400507 ar.flags = flags;
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500508
509 ret = ext4_mb_new_blocks(handle, &ar, errp);
510 if (count)
511 *count = ar.len;
Mingming Caod2a17632008-07-14 17:52:37 -0400512 /*
Eric Sandeen72b8ab92010-05-16 11:00:00 -0400513 * Account for the allocated meta blocks. We will never
514 * fail EDQUOT for metdata, but we do account for it.
Mingming Caod2a17632008-07-14 17:52:37 -0400515 */
Theodore Ts'of2321092011-01-10 12:12:36 -0500516 if (!(*errp) &&
517 ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) {
Mingming Caod2a17632008-07-14 17:52:37 -0400518 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500519 EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
Mingming Caod2a17632008-07-14 17:52:37 -0400520 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
Aditya Kali7b415bf2011-09-09 19:04:51 -0400521 dquot_alloc_block_nofail(inode,
522 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
Mingming Caod2a17632008-07-14 17:52:37 -0400523 }
524 return ret;
525}
526
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700527/**
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400528 * ext4_count_free_clusters() -- count filesystem free clusters
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700529 * @sb: superblock
530 *
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400531 * Adds up the number of free clusters from each block group.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700532 */
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400533ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700534{
Mingming Cao617ba132006-10-11 01:20:53 -0700535 ext4_fsblk_t desc_count;
536 struct ext4_group_desc *gdp;
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500537 ext4_group_t i;
Theodore Ts'o8df96752009-05-01 08:50:38 -0400538 ext4_group_t ngroups = ext4_get_groups_count(sb);
Mingming Cao617ba132006-10-11 01:20:53 -0700539#ifdef EXT4FS_DEBUG
540 struct ext4_super_block *es;
541 ext4_fsblk_t bitmap_count;
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500542 unsigned int x;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700543 struct buffer_head *bitmap_bh = NULL;
544
Mingming Cao617ba132006-10-11 01:20:53 -0700545 es = EXT4_SB(sb)->s_es;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700546 desc_count = 0;
547 bitmap_count = 0;
548 gdp = NULL;
549
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700550 for (i = 0; i < ngroups; i++) {
Mingming Cao617ba132006-10-11 01:20:53 -0700551 gdp = ext4_get_group_desc(sb, i, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700552 if (!gdp)
553 continue;
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400554 desc_count += ext4_free_group_clusters(sb, gdp);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700555 brelse(bitmap_bh);
Theodore Ts'o574ca172008-07-11 19:27:31 -0400556 bitmap_bh = ext4_read_block_bitmap(sb, i);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700557 if (bitmap_bh == NULL)
558 continue;
559
Mingming Cao617ba132006-10-11 01:20:53 -0700560 x = ext4_count_free(bitmap_bh, sb->s_blocksize);
Thadeu Lima de Souza Cascardo9fd97842009-01-26 19:26:26 -0500561 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400562 i, ext4_free_group_clusters(sb, gdp), x);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700563 bitmap_count += x;
564 }
565 brelse(bitmap_bh);
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400566 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
567 ", computed = %llu, %llu\n",
568 EXT4_B2C(sbi, ext4_free_blocks_count(es)),
Theodore Ts'o4776004f2008-09-08 23:00:52 -0400569 desc_count, bitmap_count);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700570 return bitmap_count;
571#else
572 desc_count = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700573 for (i = 0; i < ngroups; i++) {
Mingming Cao617ba132006-10-11 01:20:53 -0700574 gdp = ext4_get_group_desc(sb, i, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700575 if (!gdp)
576 continue;
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400577 desc_count += ext4_free_group_clusters(sb, gdp);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700578 }
579
580 return desc_count;
581#endif
582}
583
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500584static inline int test_root(ext4_group_t a, int b)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700585{
586 int num = b;
587
588 while (a > num)
589 num *= b;
590 return num == a;
591}
592
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500593static int ext4_group_sparse(ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700594{
595 if (group <= 1)
596 return 1;
597 if (!(group & 1))
598 return 0;
599 return (test_root(group, 7) || test_root(group, 5) ||
600 test_root(group, 3));
601}
602
603/**
Mingming Cao617ba132006-10-11 01:20:53 -0700604 * ext4_bg_has_super - number of blocks used by the superblock in group
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700605 * @sb: superblock for filesystem
606 * @group: group number to check
607 *
608 * Return the number of blocks used by the superblock (primary or backup)
609 * in this group. Currently this will be only 0 or 1.
610 */
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500611int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700612{
Mingming Cao617ba132006-10-11 01:20:53 -0700613 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
614 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
615 !ext4_group_sparse(group))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700616 return 0;
617 return 1;
618}
619
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500620static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
621 ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700622{
Mingming Cao617ba132006-10-11 01:20:53 -0700623 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500624 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
625 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700626
627 if (group == first || group == first + 1 || group == last)
628 return 1;
629 return 0;
630}
631
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500632static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
633 ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700634{
Theodore Ts'o8dadb192009-11-23 07:24:38 -0500635 if (!ext4_bg_has_super(sb, group))
636 return 0;
637
638 if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
639 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
640 else
641 return EXT4_SB(sb)->s_gdb_count;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700642}
643
644/**
Mingming Cao617ba132006-10-11 01:20:53 -0700645 * ext4_bg_num_gdb - number of blocks used by the group table in group
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700646 * @sb: superblock for filesystem
647 * @group: group number to check
648 *
649 * Return the number of blocks used by the group descriptor table
650 * (primary or backup) in this group. In the future there may be a
651 * different number of descriptor blocks in each group.
652 */
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500653unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700654{
655 unsigned long first_meta_bg =
Mingming Cao617ba132006-10-11 01:20:53 -0700656 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
657 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700658
Mingming Cao617ba132006-10-11 01:20:53 -0700659 if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700660 metagroup < first_meta_bg)
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400661 return ext4_bg_num_gdb_nometa(sb, group);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700662
Mingming Cao617ba132006-10-11 01:20:53 -0700663 return ext4_bg_num_gdb_meta(sb,group);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700664
665}
Theodore Ts'oc2ea3fd2008-10-10 09:40:52 -0400666
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400667/*
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400668 * This function returns the number of file system metadata clusters at
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400669 * the beginning of a block group, including the reserved gdt blocks.
670 */
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400671unsigned ext4_num_base_meta_clusters(struct super_block *sb,
672 ext4_group_t block_group)
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400673{
674 struct ext4_sb_info *sbi = EXT4_SB(sb);
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400675 unsigned num;
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400676
677 /* Check for superblock and gdt backups in this group */
678 num = ext4_bg_has_super(sb, block_group);
679
680 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
681 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
682 sbi->s_desc_per_block) {
683 if (num) {
684 num += ext4_bg_num_gdb(sb, block_group);
685 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
686 }
687 } else { /* For META_BG_BLOCK_GROUPS */
688 num += ext4_bg_num_gdb(sb, block_group);
689 }
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400690 return EXT4_NUM_B2C(sbi, num);
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400691}
Eric Sandeenf86186b2011-06-28 10:01:31 -0400692/**
693 * ext4_inode_to_goal_block - return a hint for block allocation
694 * @inode: inode for block allocation
695 *
696 * Return the ideal location to start allocating blocks for a
697 * newly created inode.
698 */
699ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
700{
701 struct ext4_inode_info *ei = EXT4_I(inode);
702 ext4_group_t block_group;
703 ext4_grpblk_t colour;
704 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
705 ext4_fsblk_t bg_start;
706 ext4_fsblk_t last_block;
707
708 block_group = ei->i_block_group;
709 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
710 /*
711 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
712 * block groups per flexgroup, reserve the first block
713 * group for directories and special files. Regular
714 * files will start at the second block group. This
715 * tends to speed up directory access and improves
716 * fsck times.
717 */
718 block_group &= ~(flex_size-1);
719 if (S_ISREG(inode->i_mode))
720 block_group++;
721 }
722 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
723 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
724
725 /*
726 * If we are doing delayed allocation, we don't need take
727 * colour into account.
728 */
729 if (test_opt(inode->i_sb, DELALLOC))
730 return bg_start;
731
732 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
733 colour = (current->pid % 16) *
734 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
735 else
736 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
737 return bg_start + colour;
738}
739