2 * linux/fs/minix/bitmap.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * Modified for 680x0 by Hamish Macdonald
9 * Fixed for 680x0 by Andreas Schwab
12 /* bitmap.c contains the code that handles the inode and block bitmaps */
15 #include <linux/buffer_head.h>
16 #include <linux/bitops.h>
17 #include <linux/sched.h>
19 static const int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
21 static DEFINE_SPINLOCK(bitmap_lock);
23 static unsigned long count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits)
25 unsigned i, j, sum = 0;
26 struct buffer_head *bh;
27 unsigned numblocks = minix_blocks_needed(numbits, blocksize);
29 for (i=0; i<numblocks-1; i++) {
32 for (j=0; j<bh->b_size; j++)
33 sum += nibblemap[bh->b_data[j] & 0xf]
34 + nibblemap[(bh->b_data[j]>>4) & 0xf];
37 if (numblocks==0 || !(bh=map[numblocks-1]))
39 i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2;
41 sum += nibblemap[bh->b_data[j] & 0xf]
42 + nibblemap[(bh->b_data[j]>>4) & 0xf];
47 i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1);
48 sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf];
49 sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf];
54 void minix_free_block(struct inode *inode, unsigned long block)
56 struct super_block *sb = inode->i_sb;
57 struct minix_sb_info *sbi = minix_sb(sb);
58 struct buffer_head *bh;
59 int k = sb->s_blocksize_bits + 3;
60 unsigned long bit, zone;
62 if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
63 printk("Trying to free block not in datazone\n");
66 zone = block - sbi->s_firstdatazone + 1;
67 bit = zone & ((1<<k) - 1);
69 if (zone >= sbi->s_zmap_blocks) {
70 printk("minix_free_block: nonexistent bitmap buffer\n");
73 bh = sbi->s_zmap[zone];
74 spin_lock(&bitmap_lock);
75 if (!minix_test_and_clear_bit(bit, bh->b_data))
76 printk("minix_free_block (%s:%lu): bit already cleared\n",
78 spin_unlock(&bitmap_lock);
79 mark_buffer_dirty(bh);
83 int minix_new_block(struct inode * inode)
85 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
86 int bits_per_zone = 8 * inode->i_sb->s_blocksize;
89 for (i = 0; i < sbi->s_zmap_blocks; i++) {
90 struct buffer_head *bh = sbi->s_zmap[i];
93 spin_lock(&bitmap_lock);
94 j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
95 if (j < bits_per_zone) {
96 minix_set_bit(j, bh->b_data);
97 spin_unlock(&bitmap_lock);
98 mark_buffer_dirty(bh);
99 j += i * bits_per_zone + sbi->s_firstdatazone-1;
100 if (j < sbi->s_firstdatazone || j >= sbi->s_nzones)
104 spin_unlock(&bitmap_lock);
109 unsigned long minix_count_free_blocks(struct super_block *sb)
111 struct minix_sb_info *sbi = minix_sb(sb);
112 u32 bits = sbi->s_nzones - (sbi->s_firstdatazone + 1);
114 return (count_free(sbi->s_zmap, sb->s_blocksize, bits)
115 << sbi->s_log_zone_size);
119 minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
122 struct minix_sb_info *sbi = minix_sb(sb);
123 struct minix_inode *p;
125 if (!ino || ino > sbi->s_ninodes) {
126 printk("Bad inode number on dev %s: %ld is out of range\n",
127 sb->s_id, (long)ino);
131 block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
132 ino / MINIX_INODES_PER_BLOCK;
133 *bh = sb_bread(sb, block);
135 printk("Unable to read inode block\n");
138 p = (void *)(*bh)->b_data;
139 return p + ino % MINIX_INODES_PER_BLOCK;
142 struct minix2_inode *
143 minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
146 struct minix_sb_info *sbi = minix_sb(sb);
147 struct minix2_inode *p;
148 int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
151 if (!ino || ino > sbi->s_ninodes) {
152 printk("Bad inode number on dev %s: %ld is out of range\n",
153 sb->s_id, (long)ino);
157 block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
158 ino / minix2_inodes_per_block;
159 *bh = sb_bread(sb, block);
161 printk("Unable to read inode block\n");
164 p = (void *)(*bh)->b_data;
165 return p + ino % minix2_inodes_per_block;
168 /* Clear the link count and mode of a deleted inode on disk. */
170 static void minix_clear_inode(struct inode *inode)
172 struct buffer_head *bh = NULL;
174 if (INODE_VERSION(inode) == MINIX_V1) {
175 struct minix_inode *raw_inode;
176 raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
178 raw_inode->i_nlinks = 0;
179 raw_inode->i_mode = 0;
182 struct minix2_inode *raw_inode;
183 raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
185 raw_inode->i_nlinks = 0;
186 raw_inode->i_mode = 0;
190 mark_buffer_dirty(bh);
195 void minix_free_inode(struct inode * inode)
197 struct super_block *sb = inode->i_sb;
198 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
199 struct buffer_head *bh;
200 int k = sb->s_blocksize_bits + 3;
201 unsigned long ino, bit;
204 if (ino < 1 || ino > sbi->s_ninodes) {
205 printk("minix_free_inode: inode 0 or nonexistent inode\n");
208 bit = ino & ((1<<k) - 1);
210 if (ino >= sbi->s_imap_blocks) {
211 printk("minix_free_inode: nonexistent imap in superblock\n");
215 minix_clear_inode(inode); /* clear on-disk copy */
217 bh = sbi->s_imap[ino];
218 spin_lock(&bitmap_lock);
219 if (!minix_test_and_clear_bit(bit, bh->b_data))
220 printk("minix_free_inode: bit %lu already cleared\n", bit);
221 spin_unlock(&bitmap_lock);
222 mark_buffer_dirty(bh);
225 struct inode *minix_new_inode(const struct inode *dir, int mode, int *error)
227 struct super_block *sb = dir->i_sb;
228 struct minix_sb_info *sbi = minix_sb(sb);
229 struct inode *inode = new_inode(sb);
230 struct buffer_head * bh;
231 int bits_per_zone = 8 * sb->s_blocksize;
242 spin_lock(&bitmap_lock);
243 for (i = 0; i < sbi->s_imap_blocks; i++) {
245 j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
246 if (j < bits_per_zone)
249 if (!bh || j >= bits_per_zone) {
250 spin_unlock(&bitmap_lock);
254 if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */
255 spin_unlock(&bitmap_lock);
256 printk("minix_new_inode: bit already set\n");
260 spin_unlock(&bitmap_lock);
261 mark_buffer_dirty(bh);
262 j += i * bits_per_zone;
263 if (!j || j > sbi->s_ninodes) {
267 inode_init_owner(inode, dir, mode);
269 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
271 memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u));
272 insert_inode_hash(inode);
273 mark_inode_dirty(inode);
279 unsigned long minix_count_free_inodes(struct super_block *sb)
281 struct minix_sb_info *sbi = minix_sb(sb);
282 u32 bits = sbi->s_ninodes + 1;
284 return count_free(sbi->s_imap, sb->s_blocksize, bits);