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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/minix/bitmap.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * Modified for 680x0 by Hamish Macdonald
9 * Fixed for 680x0 by Andreas Schwab
10 */
11
12/* bitmap.c contains the code that handles the inode and block bitmaps */
13
14#include "minix.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/buffer_head.h>
16#include <linux/bitops.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040017#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
Al Virocc467592009-06-16 23:47:45 -040019static DEFINE_SPINLOCK(bitmap_lock);
20
Al Virof1fd3062011-08-26 22:38:50 -040021/*
22 * bitmap consists of blocks filled with 16bit words
23 * bit set == busy, bit clear == free
24 * endianness is a mess, but for counting zero bits it really doesn't matter...
25 */
26static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits)
Linus Torvalds1da177e2005-04-16 15:20:36 -070027{
Al Virof1fd3062011-08-26 22:38:50 -040028 __u32 sum = 0;
29 unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
30
31 while (blocks--) {
32 unsigned words = blocksize / 2;
33 __u16 *p = (__u16 *)(*map++)->b_data;
34 while (words--)
35 sum += 16 - hweight16(*p++);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 }
37
Al Virof1fd3062011-08-26 22:38:50 -040038 return sum;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039}
40
Andries Brouwer939b00d2007-02-12 00:52:49 -080041void minix_free_block(struct inode *inode, unsigned long block)
Linus Torvalds1da177e2005-04-16 15:20:36 -070042{
Andries Brouwer939b00d2007-02-12 00:52:49 -080043 struct super_block *sb = inode->i_sb;
44 struct minix_sb_info *sbi = minix_sb(sb);
45 struct buffer_head *bh;
46 int k = sb->s_blocksize_bits + 3;
47 unsigned long bit, zone;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
49 if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
Denis Vlasenko11b84482006-03-25 03:07:42 -080050 printk("Trying to free block not in datazone\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 return;
52 }
53 zone = block - sbi->s_firstdatazone + 1;
Andries Brouwer939b00d2007-02-12 00:52:49 -080054 bit = zone & ((1<<k) - 1);
55 zone >>= k;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 if (zone >= sbi->s_zmap_blocks) {
57 printk("minix_free_block: nonexistent bitmap buffer\n");
58 return;
59 }
60 bh = sbi->s_zmap[zone];
Al Virocc467592009-06-16 23:47:45 -040061 spin_lock(&bitmap_lock);
Andries Brouwer939b00d2007-02-12 00:52:49 -080062 if (!minix_test_and_clear_bit(bit, bh->b_data))
63 printk("minix_free_block (%s:%lu): bit already cleared\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 sb->s_id, block);
Al Virocc467592009-06-16 23:47:45 -040065 spin_unlock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 mark_buffer_dirty(bh);
67 return;
68}
69
70int minix_new_block(struct inode * inode)
71{
72 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
Andries Brouwer939b00d2007-02-12 00:52:49 -080073 int bits_per_zone = 8 * inode->i_sb->s_blocksize;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 int i;
75
76 for (i = 0; i < sbi->s_zmap_blocks; i++) {
77 struct buffer_head *bh = sbi->s_zmap[i];
78 int j;
79
Al Virocc467592009-06-16 23:47:45 -040080 spin_lock(&bitmap_lock);
Andries Brouwer939b00d2007-02-12 00:52:49 -080081 j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
82 if (j < bits_per_zone) {
83 minix_set_bit(j, bh->b_data);
Al Virocc467592009-06-16 23:47:45 -040084 spin_unlock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 mark_buffer_dirty(bh);
Andries Brouwer939b00d2007-02-12 00:52:49 -080086 j += i * bits_per_zone + sbi->s_firstdatazone-1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 if (j < sbi->s_firstdatazone || j >= sbi->s_nzones)
88 break;
89 return j;
90 }
Al Virocc467592009-06-16 23:47:45 -040091 spin_unlock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 }
93 return 0;
94}
95
Josh Boyer016e8d42011-08-19 14:50:26 -040096unsigned long minix_count_free_blocks(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097{
Josh Boyer016e8d42011-08-19 14:50:26 -040098 struct minix_sb_info *sbi = minix_sb(sb);
99 u32 bits = sbi->s_nzones - (sbi->s_firstdatazone + 1);
100
101 return (count_free(sbi->s_zmap, sb->s_blocksize, bits)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 << sbi->s_log_zone_size);
103}
104
105struct minix_inode *
106minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
107{
108 int block;
109 struct minix_sb_info *sbi = minix_sb(sb);
110 struct minix_inode *p;
111
112 if (!ino || ino > sbi->s_ninodes) {
113 printk("Bad inode number on dev %s: %ld is out of range\n",
114 sb->s_id, (long)ino);
115 return NULL;
116 }
117 ino--;
118 block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
119 ino / MINIX_INODES_PER_BLOCK;
120 *bh = sb_bread(sb, block);
121 if (!*bh) {
Denis Vlasenko11b84482006-03-25 03:07:42 -0800122 printk("Unable to read inode block\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 return NULL;
124 }
125 p = (void *)(*bh)->b_data;
126 return p + ino % MINIX_INODES_PER_BLOCK;
127}
128
129struct minix2_inode *
130minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
131{
132 int block;
133 struct minix_sb_info *sbi = minix_sb(sb);
134 struct minix2_inode *p;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800135 int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
137 *bh = NULL;
138 if (!ino || ino > sbi->s_ninodes) {
139 printk("Bad inode number on dev %s: %ld is out of range\n",
140 sb->s_id, (long)ino);
141 return NULL;
142 }
143 ino--;
144 block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
Andries Brouwer939b00d2007-02-12 00:52:49 -0800145 ino / minix2_inodes_per_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 *bh = sb_bread(sb, block);
147 if (!*bh) {
Denis Vlasenko11b84482006-03-25 03:07:42 -0800148 printk("Unable to read inode block\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 return NULL;
150 }
151 p = (void *)(*bh)->b_data;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800152 return p + ino % minix2_inodes_per_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
154
155/* Clear the link count and mode of a deleted inode on disk. */
156
157static void minix_clear_inode(struct inode *inode)
158{
159 struct buffer_head *bh = NULL;
160
161 if (INODE_VERSION(inode) == MINIX_V1) {
162 struct minix_inode *raw_inode;
163 raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
164 if (raw_inode) {
165 raw_inode->i_nlinks = 0;
166 raw_inode->i_mode = 0;
167 }
168 } else {
169 struct minix2_inode *raw_inode;
170 raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
171 if (raw_inode) {
172 raw_inode->i_nlinks = 0;
173 raw_inode->i_mode = 0;
174 }
175 }
176 if (bh) {
177 mark_buffer_dirty(bh);
178 brelse (bh);
179 }
180}
181
182void minix_free_inode(struct inode * inode)
183{
Andries Brouwer939b00d2007-02-12 00:52:49 -0800184 struct super_block *sb = inode->i_sb;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800186 struct buffer_head *bh;
187 int k = sb->s_blocksize_bits + 3;
188 unsigned long ino, bit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190 ino = inode->i_ino;
191 if (ino < 1 || ino > sbi->s_ninodes) {
192 printk("minix_free_inode: inode 0 or nonexistent inode\n");
Al Viro5ccb4a72010-06-04 22:27:38 -0400193 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 }
Andries Brouwer939b00d2007-02-12 00:52:49 -0800195 bit = ino & ((1<<k) - 1);
196 ino >>= k;
197 if (ino >= sbi->s_imap_blocks) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 printk("minix_free_inode: nonexistent imap in superblock\n");
Al Viro5ccb4a72010-06-04 22:27:38 -0400199 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 }
201
202 minix_clear_inode(inode); /* clear on-disk copy */
203
Andries Brouwer939b00d2007-02-12 00:52:49 -0800204 bh = sbi->s_imap[ino];
Al Virocc467592009-06-16 23:47:45 -0400205 spin_lock(&bitmap_lock);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800206 if (!minix_test_and_clear_bit(bit, bh->b_data))
207 printk("minix_free_inode: bit %lu already cleared\n", bit);
Al Virocc467592009-06-16 23:47:45 -0400208 spin_unlock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 mark_buffer_dirty(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210}
211
Al Viro4f45ba32011-07-26 02:48:39 -0400212struct inode *minix_new_inode(const struct inode *dir, umode_t mode, int *error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
214 struct super_block *sb = dir->i_sb;
215 struct minix_sb_info *sbi = minix_sb(sb);
216 struct inode *inode = new_inode(sb);
217 struct buffer_head * bh;
Andries Brouwer939b00d2007-02-12 00:52:49 -0800218 int bits_per_zone = 8 * sb->s_blocksize;
219 unsigned long j;
220 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
222 if (!inode) {
223 *error = -ENOMEM;
224 return NULL;
225 }
Andries Brouwer939b00d2007-02-12 00:52:49 -0800226 j = bits_per_zone;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 bh = NULL;
228 *error = -ENOSPC;
Al Virocc467592009-06-16 23:47:45 -0400229 spin_lock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 for (i = 0; i < sbi->s_imap_blocks; i++) {
231 bh = sbi->s_imap[i];
Andries Brouwer939b00d2007-02-12 00:52:49 -0800232 j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
233 if (j < bits_per_zone)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 break;
235 }
Andries Brouwer939b00d2007-02-12 00:52:49 -0800236 if (!bh || j >= bits_per_zone) {
Al Virocc467592009-06-16 23:47:45 -0400237 spin_unlock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 iput(inode);
239 return NULL;
240 }
Andries Brouwer939b00d2007-02-12 00:52:49 -0800241 if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */
Al Virocc467592009-06-16 23:47:45 -0400242 spin_unlock(&bitmap_lock);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800243 printk("minix_new_inode: bit already set\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 iput(inode);
245 return NULL;
246 }
Al Virocc467592009-06-16 23:47:45 -0400247 spin_unlock(&bitmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 mark_buffer_dirty(bh);
Andries Brouwer939b00d2007-02-12 00:52:49 -0800249 j += i * bits_per_zone;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 if (!j || j > sbi->s_ninodes) {
251 iput(inode);
252 return NULL;
253 }
Dmitry Monakhov9eed1fb2010-03-04 17:32:14 +0300254 inode_init_owner(inode, dir, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 inode->i_ino = j;
256 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
Theodore Ts'oba52de12006-09-27 01:50:49 -0700257 inode->i_blocks = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u));
259 insert_inode_hash(inode);
260 mark_inode_dirty(inode);
261
262 *error = 0;
263 return inode;
264}
265
Josh Boyer016e8d42011-08-19 14:50:26 -0400266unsigned long minix_count_free_inodes(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267{
Josh Boyer016e8d42011-08-19 14:50:26 -0400268 struct minix_sb_info *sbi = minix_sb(sb);
269 u32 bits = sbi->s_ninodes + 1;
270
271 return count_free(sbi->s_imap, sb->s_blocksize, bits);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272}