blob: 1b5089067d018d581c68242f39fcf522a8fee55d [file] [log] [blame]
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
Eric Sandeen5f163cc2012-01-04 22:33:28 -050026static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
27 ext4_group_t block_group);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070028/*
29 * balloc.c contains the blocks allocation and deallocation routines
30 */
31
32/*
Theodore Ts'o3212a802011-09-09 18:46:51 -040033 * Calculate the block group number and offset into the block/cluster
34 * allocation bitmap, given a block number
Andrew Morton72b64b52006-10-11 01:21:18 -070035 */
36void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
Avantika Mathurfd2d4292008-01-28 23:58:27 -050037 ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
Andrew Morton72b64b52006-10-11 01:21:18 -070038{
Dave Kleikamp8c55e202007-05-24 13:04:54 -040039 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
Andrew Morton72b64b52006-10-11 01:21:18 -070040 ext4_grpblk_t offset;
41
Dave Kleikamp8c55e202007-05-24 13:04:54 -040042 blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
Theodore Ts'o3212a802011-09-09 18:46:51 -040043 offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >>
44 EXT4_SB(sb)->s_cluster_bits;
Andrew Morton72b64b52006-10-11 01:21:18 -070045 if (offsetp)
46 *offsetp = offset;
47 if (blockgrpp)
Dave Kleikamp8c55e202007-05-24 13:04:54 -040048 *blockgrpp = blocknr;
Andrew Morton72b64b52006-10-11 01:21:18 -070049
50}
51
Jose R. Santos0bf7e832008-06-03 14:07:29 -040052static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
53 ext4_group_t block_group)
54{
55 ext4_group_t actual_group;
Aneesh Kumar K.V74778272008-07-11 19:27:31 -040056 ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
Jose R. Santos0bf7e832008-06-03 14:07:29 -040057 if (actual_group == block_group)
58 return 1;
59 return 0;
60}
61
Theodore Ts'od5b8f312011-09-09 18:44:51 -040062/* Return the number of clusters used for file system metadata; this
63 * represents the overhead needed by the file system.
64 */
65unsigned ext4_num_overhead_clusters(struct super_block *sb,
66 ext4_group_t block_group,
67 struct ext4_group_desc *gdp)
Jose R. Santos0bf7e832008-06-03 14:07:29 -040068{
Theodore Ts'od5b8f312011-09-09 18:44:51 -040069 unsigned num_clusters;
70 int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c;
71 ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group);
72 ext4_fsblk_t itbl_blk;
Jose R. Santos0bf7e832008-06-03 14:07:29 -040073 struct ext4_sb_info *sbi = EXT4_SB(sb);
Jose R. Santos0bf7e832008-06-03 14:07:29 -040074
Theodore Ts'od5b8f312011-09-09 18:44:51 -040075 /* This is the number of clusters used by the superblock,
76 * block group descriptors, and reserved block group
77 * descriptor blocks */
78 num_clusters = ext4_num_base_meta_clusters(sb, block_group);
Jose R. Santos0bf7e832008-06-03 14:07:29 -040079
Theodore Ts'od5b8f312011-09-09 18:44:51 -040080 /*
81 * For the allocation bitmaps and inode table, we first need
82 * to check to see if the block is in the block group. If it
83 * is, then check to see if the cluster is already accounted
84 * for in the clusters used for the base metadata cluster, or
85 * if we can increment the base metadata cluster to include
86 * that block. Otherwise, we will have to track the cluster
87 * used for the allocation bitmap or inode table explicitly.
88 * Normally all of these blocks are contiguous, so the special
89 * case handling shouldn't be necessary except for *very*
90 * unusual file system layouts.
91 */
92 if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
Theodore Ts'ob0dd6b72012-06-07 18:56:06 -040093 block_cluster = EXT4_B2C(sbi,
94 ext4_block_bitmap(sb, gdp) - start);
Theodore Ts'od5b8f312011-09-09 18:44:51 -040095 if (block_cluster < num_clusters)
96 block_cluster = -1;
97 else if (block_cluster == num_clusters) {
98 num_clusters++;
99 block_cluster = -1;
Jose R. Santos0bf7e832008-06-03 14:07:29 -0400100 }
101 }
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400102
103 if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
104 inode_cluster = EXT4_B2C(sbi,
Theodore Ts'ob0dd6b72012-06-07 18:56:06 -0400105 ext4_inode_bitmap(sb, gdp) - start);
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400106 if (inode_cluster < num_clusters)
107 inode_cluster = -1;
108 else if (inode_cluster == num_clusters) {
109 num_clusters++;
110 inode_cluster = -1;
111 }
112 }
113
114 itbl_blk = ext4_inode_table(sb, gdp);
115 for (i = 0; i < sbi->s_itb_per_group; i++) {
116 if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
Theodore Ts'ob0dd6b72012-06-07 18:56:06 -0400117 c = EXT4_B2C(sbi, itbl_blk + i - start);
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400118 if ((c < num_clusters) || (c == inode_cluster) ||
119 (c == block_cluster) || (c == itbl_cluster))
120 continue;
121 if (c == num_clusters) {
122 num_clusters++;
123 continue;
124 }
125 num_clusters++;
126 itbl_cluster = c;
127 }
128 }
129
130 if (block_cluster != -1)
131 num_clusters++;
132 if (inode_cluster != -1)
133 num_clusters++;
134
135 return num_clusters;
Jose R. Santos0bf7e832008-06-03 14:07:29 -0400136}
Theodore Ts'oc2ea3fd2008-10-10 09:40:52 -0400137
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400138static unsigned int num_clusters_in_group(struct super_block *sb,
139 ext4_group_t block_group)
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400140{
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400141 unsigned int blocks;
142
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400143 if (block_group == ext4_get_groups_count(sb) - 1) {
144 /*
145 * Even though mke2fs always initializes the first and
146 * last group, just in case some other tool was used,
147 * we need to make sure we calculate the right free
148 * blocks.
149 */
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400150 blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) -
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400151 ext4_group_first_block_no(sb, block_group);
152 } else
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400153 blocks = EXT4_BLOCKS_PER_GROUP(sb);
154 return EXT4_NUM_B2C(EXT4_SB(sb), blocks);
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400155}
156
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400157/* Initializes an uninitialized block bitmap */
158void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
159 ext4_group_t block_group,
160 struct ext4_group_desc *gdp)
Andreas Dilger717d50e2007-10-16 18:38:25 -0400161{
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400162 unsigned int bit, bit_max;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400163 struct ext4_sb_info *sbi = EXT4_SB(sb);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400164 ext4_fsblk_t start, tmp;
165 int flex_bg = 0;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400166
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400167 J_ASSERT_BH(bh, buffer_locked(bh));
Andreas Dilger717d50e2007-10-16 18:38:25 -0400168
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400169 /* If checksum is bad mark all blocks used to prevent allocation
170 * essentially implementing a per-group read-only flag. */
Darrick J. Wongfeb0ab32012-04-29 18:45:10 -0400171 if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400172 ext4_error(sb, "Checksum bad for group %u", block_group);
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400173 ext4_free_group_clusters_set(sb, gdp, 0);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400174 ext4_free_inodes_set(sb, gdp, 0);
175 ext4_itable_unused_set(sb, gdp, 0);
176 memset(bh->b_data, 0xff, sb->s_blocksize);
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400177 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
178 EXT4_BLOCKS_PER_GROUP(sb) / 8);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400179 return;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400180 }
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400181 memset(bh->b_data, 0, sb->s_blocksize);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400182
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400183 bit_max = ext4_num_base_meta_clusters(sb, block_group);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400184 for (bit = 0; bit < bit_max; bit++)
185 ext4_set_bit(bit, bh->b_data);
Akinobu Mitad00a6d72008-04-17 10:38:59 -0400186
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400187 start = ext4_group_first_block_no(sb, block_group);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400188
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400189 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
190 flex_bg = 1;
Andreas Dilger717d50e2007-10-16 18:38:25 -0400191
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400192 /* Set bits for block and inode bitmaps, and inode table */
193 tmp = ext4_block_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);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400196
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400197 tmp = ext4_inode_bitmap(sb, gdp);
198 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400199 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400200
201 tmp = ext4_inode_table(sb, gdp);
202 for (; tmp < ext4_inode_table(sb, gdp) +
203 sbi->s_itb_per_group; tmp++) {
Jose R. Santos0bf7e832008-06-03 14:07:29 -0400204 if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400205 ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400206 }
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400207
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400208 /*
209 * Also if the number of blocks within the group is less than
210 * the blocksize * 8 ( which is the size of bitmap ), set rest
211 * of the block bitmap to 1
212 */
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400213 ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group),
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400214 sb->s_blocksize * 8, bh->b_data);
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400215 ext4_block_bitmap_csum_set(sb, block_group, gdp, bh,
216 EXT4_BLOCKS_PER_GROUP(sb) / 8);
Darrick J. Wongfeb0ab32012-04-29 18:45:10 -0400217 ext4_group_desc_csum_set(sb, block_group, gdp);
Andreas Dilger717d50e2007-10-16 18:38:25 -0400218}
219
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400220/* Return the number of free blocks in a block group. It is used when
221 * the block bitmap is uninitialized, so we can't just count the bits
222 * in the bitmap. */
Theodore Ts'ocff1dfd72011-09-09 19:12:51 -0400223unsigned ext4_free_clusters_after_init(struct super_block *sb,
224 ext4_group_t block_group,
225 struct ext4_group_desc *gdp)
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400226{
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400227 return num_clusters_in_group(sb, block_group) -
228 ext4_num_overhead_clusters(sb, block_group, gdp);
Theodore Ts'ofd034a82011-09-09 18:42:51 -0400229}
Andreas Dilger717d50e2007-10-16 18:38:25 -0400230
Andrew Morton72b64b52006-10-11 01:21:18 -0700231/*
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700232 * The free blocks are managed by bitmaps. A file system contains several
233 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
234 * block for inodes, N blocks for the inode table and data blocks.
235 *
236 * The file system contains group descriptors which are located after the
237 * super block. Each descriptor contains the number of the bitmap block and
238 * the free blocks count in the block. The descriptors are loaded in memory
Aneesh Kumar K.Ve6274322007-02-20 13:57:58 -0800239 * when a file system is mounted (see ext4_fill_super).
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700240 */
241
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700242/**
Mingming Cao617ba132006-10-11 01:20:53 -0700243 * ext4_get_group_desc() -- load group descriptor from disk
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700244 * @sb: super block
245 * @block_group: given block group
246 * @bh: pointer to the buffer head to store the block
247 * group descriptor
248 */
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400249struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500250 ext4_group_t block_group,
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400251 struct buffer_head **bh)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700252{
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500253 unsigned int group_desc;
254 unsigned int offset;
Theodore Ts'o8df96752009-05-01 08:50:38 -0400255 ext4_group_t ngroups = ext4_get_groups_count(sb);
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400256 struct ext4_group_desc *desc;
Mingming Cao617ba132006-10-11 01:20:53 -0700257 struct ext4_sb_info *sbi = EXT4_SB(sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700258
Theodore Ts'o8df96752009-05-01 08:50:38 -0400259 if (block_group >= ngroups) {
Eric Sandeen12062dd2010-02-15 14:19:27 -0500260 ext4_error(sb, "block_group >= groups_count - block_group = %u,"
261 " groups_count = %u", block_group, ngroups);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700262
263 return NULL;
264 }
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700265
Mingming Cao617ba132006-10-11 01:20:53 -0700266 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
267 offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700268 if (!sbi->s_group_desc[group_desc]) {
Eric Sandeen12062dd2010-02-15 14:19:27 -0500269 ext4_error(sb, "Group descriptor not loaded - "
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500270 "block_group = %u, group_desc = %u, desc = %u",
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400271 block_group, group_desc, offset);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700272 return NULL;
273 }
274
Alexandre Ratchov0d1ee422006-10-11 01:21:14 -0700275 desc = (struct ext4_group_desc *)(
276 (__u8 *)sbi->s_group_desc[group_desc]->b_data +
277 offset * EXT4_DESC_SIZE(sb));
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700278 if (bh)
279 *bh = sbi->s_group_desc[group_desc];
Alexandre Ratchov0d1ee422006-10-11 01:21:14 -0700280 return desc;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700281}
282
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400283/*
284 * Return the block number which was discovered to be invalid, or 0 if
285 * the block bitmap is valid.
286 */
287static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb,
288 struct ext4_group_desc *desc,
289 unsigned int block_group,
290 struct buffer_head *bh)
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500291{
292 ext4_grpblk_t offset;
293 ext4_grpblk_t next_zero_bit;
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400294 ext4_fsblk_t blk;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500295 ext4_fsblk_t group_first_block;
296
297 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
298 /* with FLEX_BG, the inode/block bitmaps and itable
299 * blocks may not be in the group at all
300 * so the bitmap validation will be skipped for those groups
301 * or it has to also read the block group where the bitmaps
302 * are located to verify they are set.
303 */
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400304 return 0;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500305 }
306 group_first_block = ext4_group_first_block_no(sb, block_group);
307
308 /* check whether block bitmap block number is set */
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400309 blk = ext4_block_bitmap(sb, desc);
310 offset = blk - group_first_block;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500311 if (!ext4_test_bit(offset, bh->b_data))
312 /* bad block bitmap */
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400313 return blk;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500314
315 /* check whether the inode bitmap block number is set */
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400316 blk = ext4_inode_bitmap(sb, desc);
317 offset = blk - group_first_block;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500318 if (!ext4_test_bit(offset, bh->b_data))
319 /* bad block bitmap */
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400320 return blk;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500321
322 /* check whether the inode table block number is set */
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400323 blk = ext4_inode_table(sb, desc);
324 offset = blk - group_first_block;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500325 next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
326 offset + EXT4_SB(sb)->s_itb_per_group,
327 offset);
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400328 if (next_zero_bit < offset + EXT4_SB(sb)->s_itb_per_group)
329 /* bad bitmap for inode tables */
330 return blk;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500331 return 0;
332}
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400333
334void ext4_validate_block_bitmap(struct super_block *sb,
335 struct ext4_group_desc *desc,
336 unsigned int block_group,
337 struct buffer_head *bh)
338{
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400339 ext4_fsblk_t blk;
340
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400341 if (buffer_verified(bh))
342 return;
343
344 ext4_lock_group(sb, block_group);
Theodore Ts'o7a4c5de2012-08-10 13:57:52 -0400345 blk = ext4_valid_block_bitmap(sb, desc, block_group, bh);
346 if (unlikely(blk != 0)) {
347 ext4_unlock_group(sb, block_group);
348 ext4_error(sb, "bg %u: block %llu: invalid block bitmap",
349 block_group, blk);
350 return;
351 }
352 if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group,
353 desc, bh, EXT4_BLOCKS_PER_GROUP(sb) / 8))) {
354 ext4_unlock_group(sb, block_group);
355 ext4_error(sb, "bg %u: bad block bitmap checksum", block_group);
356 return;
357 }
358 set_buffer_verified(bh);
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400359 ext4_unlock_group(sb, block_group);
360}
361
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700362/**
Theodore Ts'o574ca172008-07-11 19:27:31 -0400363 * ext4_read_block_bitmap()
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700364 * @sb: super block
365 * @block_group: given block group
366 *
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500367 * Read the bitmap for a given block_group,and validate the
368 * bits for block/inode/inode tables are set in the bitmaps
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700369 *
370 * Return buffer_head on success or NULL in case of failure.
371 */
Andreas Dilger717d50e2007-10-16 18:38:25 -0400372struct buffer_head *
Theodore Ts'o813e5722012-02-20 17:52:46 -0500373ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700374{
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400375 struct ext4_group_desc *desc;
Theodore Ts'o813e5722012-02-20 17:52:46 -0500376 struct buffer_head *bh;
Aneesh Kumar K.V7c9e69f2007-10-16 23:27:02 -0700377 ext4_fsblk_t bitmap_blk;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700378
Andreas Dilger717d50e2007-10-16 18:38:25 -0400379 desc = ext4_get_group_desc(sb, block_group, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700380 if (!desc)
Aneesh Kumar K.V7c9e69f2007-10-16 23:27:02 -0700381 return NULL;
382 bitmap_blk = ext4_block_bitmap(sb, desc);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500383 bh = sb_getblk(sb, bitmap_blk);
384 if (unlikely(!bh)) {
Theodore Ts'o813e5722012-02-20 17:52:46 -0500385 ext4_error(sb, "Cannot get buffer for block bitmap - "
386 "block_group = %u, block_bitmap = %llu",
387 block_group, bitmap_blk);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500388 return NULL;
389 }
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500390
391 if (bitmap_uptodate(bh))
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400392 goto verify;
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500393
Frederic Bohec806e682008-10-10 08:09:18 -0400394 lock_buffer(bh);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500395 if (bitmap_uptodate(bh)) {
396 unlock_buffer(bh);
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400397 goto verify;
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500398 }
Aneesh Kumar K.V955ce5f2009-05-02 20:35:09 -0400399 ext4_lock_group(sb, block_group);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500400 if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
401 ext4_init_block_bitmap(sb, bh, block_group, desc);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500402 set_bitmap_uptodate(bh);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500403 set_buffer_uptodate(bh);
Aneesh Kumar K.V955ce5f2009-05-02 20:35:09 -0400404 ext4_unlock_group(sb, block_group);
Aneesh Kumar K.V3300bed2009-01-03 22:33:39 -0500405 unlock_buffer(bh);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500406 return bh;
407 }
Aneesh Kumar K.V955ce5f2009-05-02 20:35:09 -0400408 ext4_unlock_group(sb, block_group);
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500409 if (buffer_uptodate(bh)) {
410 /*
411 * if not uninit if bh is uptodate,
412 * bitmap is also uptodate
413 */
414 set_bitmap_uptodate(bh);
415 unlock_buffer(bh);
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400416 goto verify;
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500417 }
418 /*
Theodore Ts'o813e5722012-02-20 17:52:46 -0500419 * submit the buffer_head for reading
Aneesh Kumar K.V2ccb5fb2009-01-05 21:49:55 -0500420 */
Theodore Ts'o813e5722012-02-20 17:52:46 -0500421 set_buffer_new(bh);
Jiaying Zhang0562e0b2011-03-21 21:38:05 -0400422 trace_ext4_read_block_bitmap_load(sb, block_group);
Theodore Ts'o813e5722012-02-20 17:52:46 -0500423 bh->b_end_io = ext4_end_bitmap_read;
424 get_bh(bh);
425 submit_bh(READ, bh);
426 return bh;
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400427verify:
428 ext4_validate_block_bitmap(sb, desc, block_group, bh);
429 return bh;
Theodore Ts'o813e5722012-02-20 17:52:46 -0500430}
431
432/* Returns 0 on success, 1 on error */
433int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group,
434 struct buffer_head *bh)
435{
436 struct ext4_group_desc *desc;
437
438 if (!buffer_new(bh))
439 return 0;
440 desc = ext4_get_group_desc(sb, block_group, NULL);
441 if (!desc)
442 return 1;
443 wait_on_buffer(bh);
444 if (!buffer_uptodate(bh)) {
Eric Sandeen12062dd2010-02-15 14:19:27 -0500445 ext4_error(sb, "Cannot read block bitmap - "
Theodore Ts'o813e5722012-02-20 17:52:46 -0500446 "block_group = %u, block_bitmap = %llu",
Heiko Carstensd4dc4622012-02-20 17:57:24 -0500447 block_group, (unsigned long long) bh->b_blocknr);
Theodore Ts'o813e5722012-02-20 17:52:46 -0500448 return 1;
449 }
450 clear_buffer_new(bh);
451 /* Panic or remount fs read-only if block bitmap is invalid */
Darrick J. Wongfa77dcf2012-04-29 18:35:10 -0400452 ext4_validate_block_bitmap(sb, desc, block_group, bh);
Theodore Ts'o813e5722012-02-20 17:52:46 -0500453 return 0;
454}
455
456struct buffer_head *
457ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
458{
459 struct buffer_head *bh;
460
461 bh = ext4_read_block_bitmap_nowait(sb, block_group);
462 if (ext4_wait_block_bitmap(sb, block_group, bh)) {
463 put_bh(bh);
Aneesh Kumar K.Vabcb2942008-01-28 23:58:27 -0500464 return NULL;
465 }
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700466 return bh;
467}
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700468
469/**
Theodore Ts'odf55c992011-09-09 19:16:51 -0400470 * ext4_has_free_clusters()
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400471 * @sbi: in-core super block structure.
Theodore Ts'odf55c992011-09-09 19:16:51 -0400472 * @nclusters: number of needed blocks
473 * @flags: flags from ext4_mb_new_blocks()
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400474 *
Theodore Ts'odf55c992011-09-09 19:16:51 -0400475 * Check if filesystem has nclusters free & available for allocation.
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400476 * On success return 1, return 0 on failure.
477 */
Theodore Ts'odf55c992011-09-09 19:16:51 -0400478static int ext4_has_free_clusters(struct ext4_sb_info *sbi,
479 s64 nclusters, unsigned int flags)
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400480{
Theodore Ts'odf55c992011-09-09 19:16:51 -0400481 s64 free_clusters, dirty_clusters, root_clusters;
Theodore Ts'o57042652011-09-09 18:56:51 -0400482 struct percpu_counter *fcc = &sbi->s_freeclusters_counter;
Theodore Ts'odf55c992011-09-09 19:16:51 -0400483 struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter;
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400484
Theodore Ts'odf55c992011-09-09 19:16:51 -0400485 free_clusters = percpu_counter_read_positive(fcc);
486 dirty_clusters = percpu_counter_read_positive(dcc);
487 root_clusters = EXT4_B2C(sbi, ext4_r_blocks_count(sbi->s_es));
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400488
Theodore Ts'odf55c992011-09-09 19:16:51 -0400489 if (free_clusters - (nclusters + root_clusters + dirty_clusters) <
490 EXT4_FREECLUSTERS_WATERMARK) {
491 free_clusters = EXT4_C2B(sbi, percpu_counter_sum_positive(fcc));
492 dirty_clusters = percpu_counter_sum_positive(dcc);
Aneesh Kumar K.V6bc6e632008-10-10 09:39:00 -0400493 }
Theodore Ts'odf55c992011-09-09 19:16:51 -0400494 /* Check whether we have space after accounting for current
495 * dirty clusters & root reserved clusters.
Aneesh Kumar K.V6bc6e632008-10-10 09:39:00 -0400496 */
Theodore Ts'odf55c992011-09-09 19:16:51 -0400497 if (free_clusters >= ((root_clusters + nclusters) + dirty_clusters))
Eric Sandeena9960312008-10-28 00:08:17 -0400498 return 1;
Aneesh Kumar K.V5c791612008-10-08 23:12:24 -0400499
Theodore Ts'odf55c992011-09-09 19:16:51 -0400500 /* Hm, nope. Are (enough) root reserved clusters available? */
Eric W. Biederman08cefc72012-02-07 15:41:49 -0800501 if (uid_eq(sbi->s_resuid, current_fsuid()) ||
502 (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) ||
Allison Henderson55f020d2011-05-25 07:41:26 -0400503 capable(CAP_SYS_RESOURCE) ||
504 (flags & EXT4_MB_USE_ROOT_BLOCKS)) {
505
Theodore Ts'odf55c992011-09-09 19:16:51 -0400506 if (free_clusters >= (nclusters + dirty_clusters))
Eric Sandeena9960312008-10-28 00:08:17 -0400507 return 1;
508 }
509
510 return 0;
Aneesh Kumar K.Va30d542a2008-10-09 10:56:23 -0400511}
Mingming Cao07031432008-07-11 19:27:31 -0400512
Theodore Ts'oe7d5f312011-09-09 19:14:51 -0400513int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
514 s64 nclusters, unsigned int flags)
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400515{
Theodore Ts'odf55c992011-09-09 19:16:51 -0400516 if (ext4_has_free_clusters(sbi, nclusters, flags)) {
Theodore Ts'oe7d5f312011-09-09 19:14:51 -0400517 percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
Eric Sandeen8c3bf8a02008-10-28 00:08:12 -0400518 return 0;
519 } else
520 return -ENOSPC;
521}
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700522
523/**
Mingming Cao617ba132006-10-11 01:20:53 -0700524 * ext4_should_retry_alloc()
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700525 * @sb: super block
526 * @retries number of attemps has been made
527 *
Mingming Cao617ba132006-10-11 01:20:53 -0700528 * ext4_should_retry_alloc() is called when ENOSPC is returned, and if
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700529 * it is profitable to retry the operation, this function will wait
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300530 * for the current or committing transaction to complete, and then
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700531 * return TRUE.
532 *
533 * if the total number of retries exceed three times, return FALSE.
534 */
Mingming Cao617ba132006-10-11 01:20:53 -0700535int ext4_should_retry_alloc(struct super_block *sb, int *retries)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700536{
Theodore Ts'odf55c992011-09-09 19:16:51 -0400537 if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
Eric Sandeen8f64b322009-02-26 00:57:35 -0500538 (*retries)++ > 3 ||
539 !EXT4_SB(sb)->s_journal)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700540 return 0;
541
542 jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
543
Mingming Caodab291a2006-10-11 01:21:01 -0700544 return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700545}
546
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400547/*
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400548 * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
549 *
550 * @handle: handle to this transaction
551 * @inode: file inode
552 * @goal: given target block(filesystem wide)
Aditya Kali7b415bf2011-09-09 19:04:51 -0400553 * @count: pointer to total number of clusters needed
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400554 * @errp: error code
555 *
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500556 * Return 1st allocated block number on success, *count stores total account
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400557 * error stores in errp pointer
558 */
559ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
Allison Henderson55f020d2011-05-25 07:41:26 -0400560 ext4_fsblk_t goal, unsigned int flags,
561 unsigned long *count, int *errp)
Aneesh Kumar K.V654b4902008-07-11 19:27:31 -0400562{
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500563 struct ext4_allocation_request ar;
Mingming Caod2a17632008-07-14 17:52:37 -0400564 ext4_fsblk_t ret;
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500565
566 memset(&ar, 0, sizeof(ar));
567 /* Fill with neighbour allocated blocks */
568 ar.inode = inode;
569 ar.goal = goal;
570 ar.len = count ? *count : 1;
Allison Henderson55f020d2011-05-25 07:41:26 -0400571 ar.flags = flags;
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500572
573 ret = ext4_mb_new_blocks(handle, &ar, errp);
574 if (count)
575 *count = ar.len;
Mingming Caod2a17632008-07-14 17:52:37 -0400576 /*
Eric Sandeen72b8ab92010-05-16 11:00:00 -0400577 * Account for the allocated meta blocks. We will never
578 * fail EDQUOT for metdata, but we do account for it.
Mingming Caod2a17632008-07-14 17:52:37 -0400579 */
Theodore Ts'of2321092011-01-10 12:12:36 -0500580 if (!(*errp) &&
581 ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) {
Mingming Caod2a17632008-07-14 17:52:37 -0400582 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
Theodore Ts'o97df5d12008-12-12 12:41:28 -0500583 EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
Mingming Caod2a17632008-07-14 17:52:37 -0400584 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
Aditya Kali7b415bf2011-09-09 19:04:51 -0400585 dquot_alloc_block_nofail(inode,
586 EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
Mingming Caod2a17632008-07-14 17:52:37 -0400587 }
588 return ret;
589}
590
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700591/**
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400592 * ext4_count_free_clusters() -- count filesystem free clusters
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700593 * @sb: superblock
594 *
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400595 * Adds up the number of free clusters from each block group.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700596 */
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400597ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700598{
Mingming Cao617ba132006-10-11 01:20:53 -0700599 ext4_fsblk_t desc_count;
600 struct ext4_group_desc *gdp;
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500601 ext4_group_t i;
Theodore Ts'o8df96752009-05-01 08:50:38 -0400602 ext4_group_t ngroups = ext4_get_groups_count(sb);
Mingming Cao617ba132006-10-11 01:20:53 -0700603#ifdef EXT4FS_DEBUG
604 struct ext4_super_block *es;
605 ext4_fsblk_t bitmap_count;
Theodore Ts'o498e5f22008-11-05 00:14:04 -0500606 unsigned int x;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700607 struct buffer_head *bitmap_bh = NULL;
608
Mingming Cao617ba132006-10-11 01:20:53 -0700609 es = EXT4_SB(sb)->s_es;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700610 desc_count = 0;
611 bitmap_count = 0;
612 gdp = NULL;
613
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700614 for (i = 0; i < ngroups; i++) {
Mingming Cao617ba132006-10-11 01:20:53 -0700615 gdp = ext4_get_group_desc(sb, i, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700616 if (!gdp)
617 continue;
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400618 desc_count += ext4_free_group_clusters(sb, gdp);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700619 brelse(bitmap_bh);
Theodore Ts'o574ca172008-07-11 19:27:31 -0400620 bitmap_bh = ext4_read_block_bitmap(sb, i);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700621 if (bitmap_bh == NULL)
622 continue;
623
Theodore Ts'of6fb99c2012-06-30 19:14:57 -0400624 x = ext4_count_free(bitmap_bh->b_data,
625 EXT4_BLOCKS_PER_GROUP(sb) / 8);
Thadeu Lima de Souza Cascardo9fd97842009-01-26 19:26:26 -0500626 printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400627 i, ext4_free_group_clusters(sb, gdp), x);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700628 bitmap_count += x;
629 }
630 brelse(bitmap_bh);
Theodore Ts'o5dee5432011-09-09 19:10:51 -0400631 printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu"
632 ", computed = %llu, %llu\n",
Yongqiang Yang6e58ad62011-11-21 12:09:19 -0500633 EXT4_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)),
Theodore Ts'o4776004f2008-09-08 23:00:52 -0400634 desc_count, bitmap_count);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700635 return bitmap_count;
636#else
637 desc_count = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700638 for (i = 0; i < ngroups; i++) {
Mingming Cao617ba132006-10-11 01:20:53 -0700639 gdp = ext4_get_group_desc(sb, i, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700640 if (!gdp)
641 continue;
Theodore Ts'o021b65b2011-09-09 19:08:51 -0400642 desc_count += ext4_free_group_clusters(sb, gdp);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700643 }
644
645 return desc_count;
646#endif
647}
648
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500649static inline int test_root(ext4_group_t a, int b)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700650{
651 int num = b;
652
653 while (a > num)
654 num *= b;
655 return num == a;
656}
657
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500658static int ext4_group_sparse(ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700659{
660 if (group <= 1)
661 return 1;
662 if (!(group & 1))
663 return 0;
664 return (test_root(group, 7) || test_root(group, 5) ||
665 test_root(group, 3));
666}
667
668/**
Mingming Cao617ba132006-10-11 01:20:53 -0700669 * ext4_bg_has_super - number of blocks used by the superblock in group
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700670 * @sb: superblock for filesystem
671 * @group: group number to check
672 *
673 * Return the number of blocks used by the superblock (primary or backup)
674 * in this group. Currently this will be only 0 or 1.
675 */
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500676int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700677{
Mingming Cao617ba132006-10-11 01:20:53 -0700678 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
679 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
680 !ext4_group_sparse(group))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700681 return 0;
682 return 1;
683}
684
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500685static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
686 ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700687{
Mingming Cao617ba132006-10-11 01:20:53 -0700688 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500689 ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
690 ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700691
692 if (group == first || group == first + 1 || group == last)
693 return 1;
694 return 0;
695}
696
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500697static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
698 ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700699{
Theodore Ts'o8dadb192009-11-23 07:24:38 -0500700 if (!ext4_bg_has_super(sb, group))
701 return 0;
702
703 if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
704 return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
705 else
706 return EXT4_SB(sb)->s_gdb_count;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700707}
708
709/**
Mingming Cao617ba132006-10-11 01:20:53 -0700710 * ext4_bg_num_gdb - number of blocks used by the group table in group
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700711 * @sb: superblock for filesystem
712 * @group: group number to check
713 *
714 * Return the number of blocks used by the group descriptor table
715 * (primary or backup) in this group. In the future there may be a
716 * different number of descriptor blocks in each group.
717 */
Avantika Mathurfd2d4292008-01-28 23:58:27 -0500718unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700719{
720 unsigned long first_meta_bg =
Mingming Cao617ba132006-10-11 01:20:53 -0700721 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
722 unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700723
Mingming Cao617ba132006-10-11 01:20:53 -0700724 if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700725 metagroup < first_meta_bg)
Theodore Ts'oaf5bc922008-09-08 22:25:24 -0400726 return ext4_bg_num_gdb_nometa(sb, group);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700727
Mingming Cao617ba132006-10-11 01:20:53 -0700728 return ext4_bg_num_gdb_meta(sb,group);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700729
730}
Theodore Ts'oc2ea3fd2008-10-10 09:40:52 -0400731
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400732/*
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400733 * This function returns the number of file system metadata clusters at
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400734 * the beginning of a block group, including the reserved gdt blocks.
735 */
Eric Sandeen5f163cc2012-01-04 22:33:28 -0500736static unsigned ext4_num_base_meta_clusters(struct super_block *sb,
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400737 ext4_group_t block_group)
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400738{
739 struct ext4_sb_info *sbi = EXT4_SB(sb);
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400740 unsigned num;
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400741
742 /* Check for superblock and gdt backups in this group */
743 num = ext4_bg_has_super(sb, block_group);
744
745 if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
746 block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
747 sbi->s_desc_per_block) {
748 if (num) {
749 num += ext4_bg_num_gdb(sb, block_group);
750 num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
751 }
752 } else { /* For META_BG_BLOCK_GROUPS */
753 num += ext4_bg_num_gdb(sb, block_group);
754 }
Theodore Ts'od5b8f312011-09-09 18:44:51 -0400755 return EXT4_NUM_B2C(sbi, num);
Theodore Ts'o49f7f9a2011-09-09 18:40:51 -0400756}
Eric Sandeenf86186b2011-06-28 10:01:31 -0400757/**
758 * ext4_inode_to_goal_block - return a hint for block allocation
759 * @inode: inode for block allocation
760 *
761 * Return the ideal location to start allocating blocks for a
762 * newly created inode.
763 */
764ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode)
765{
766 struct ext4_inode_info *ei = EXT4_I(inode);
767 ext4_group_t block_group;
768 ext4_grpblk_t colour;
769 int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
770 ext4_fsblk_t bg_start;
771 ext4_fsblk_t last_block;
772
773 block_group = ei->i_block_group;
774 if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
775 /*
776 * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME
777 * block groups per flexgroup, reserve the first block
778 * group for directories and special files. Regular
779 * files will start at the second block group. This
780 * tends to speed up directory access and improves
781 * fsck times.
782 */
783 block_group &= ~(flex_size-1);
784 if (S_ISREG(inode->i_mode))
785 block_group++;
786 }
787 bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
788 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
789
790 /*
791 * If we are doing delayed allocation, we don't need take
792 * colour into account.
793 */
794 if (test_opt(inode->i_sb, DELALLOC))
795 return bg_start;
796
797 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
798 colour = (current->pid % 16) *
799 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
800 else
801 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
802 return bg_start + colour;
803}
804