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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [fs/] [minix/] [bitmap.c] - Blame information for rev 1777

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Line No. Rev Author Line
1 1628 jcastillo
/*
2
 *  linux/fs/minix/bitmap.c
3
 *
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 *  Copyright (C) 1991, 1992  Linus Torvalds
5
 */
6
 
7
/* bitmap.c contains the code that handles the inode and block bitmaps */
8
 
9
#include <linux/sched.h>
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#include <linux/minix_fs.h>
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#include <linux/stat.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <asm/bitops.h>
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static int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
18
 
19
static unsigned long count_free(struct buffer_head *map[], unsigned numblocks)
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{
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        unsigned i, j, sum = 0;
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        struct buffer_head *bh;
23
 
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        for (i=0; i<numblocks; i++) {
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                if (!(bh=map[i]))
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                        return(0);
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                for (j=0; j<BLOCK_SIZE; j++)
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                        sum += nibblemap[bh->b_data[j] & 0xf]
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                                + nibblemap[(bh->b_data[j]>>4)&0xf];
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        }
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        return(sum);
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}
33
 
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void minix_free_block(struct super_block * sb, int block)
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{
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        struct buffer_head * bh;
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        unsigned int bit,zone;
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        if (!sb) {
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                printk("trying to free block on nonexistent device\n");
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                return;
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        }
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        if (block < sb->u.minix_sb.s_firstdatazone ||
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            block >= sb->u.minix_sb.s_nzones) {
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                printk("trying to free block not in datazone\n");
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                return;
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        }
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        bh = get_hash_table(sb->s_dev,block,BLOCK_SIZE);
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        if (bh)
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                clear_bit(BH_Dirty, &bh->b_state);
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        brelse(bh);
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        zone = block - sb->u.minix_sb.s_firstdatazone + 1;
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        bit = zone & 8191;
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        zone >>= 13;
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        bh = sb->u.minix_sb.s_zmap[zone];
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        if (!bh) {
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                printk("minix_free_block: nonexistent bitmap buffer\n");
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                return;
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        }
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        if (!clear_bit(bit,bh->b_data))
61
                printk("free_block (%s:%d): bit already cleared\n",
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                       kdevname(sb->s_dev), block);
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        mark_buffer_dirty(bh, 1);
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        return;
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}
66
 
67
int minix_new_block(struct super_block * sb)
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{
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        struct buffer_head * bh;
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        int i,j;
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        if (!sb) {
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                printk("trying to get new block from nonexistent device\n");
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                return 0;
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        }
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repeat:
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        j = 8192;
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        for (i=0 ; i<64 ; i++)
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                if ((bh=sb->u.minix_sb.s_zmap[i]) != NULL)
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                        if ((j=find_first_zero_bit(bh->b_data, 8192)) < 8192)
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                                break;
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        if (i>=64 || !bh || j>=8192)
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                return 0;
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        if (set_bit(j,bh->b_data)) {
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                printk("new_block: bit already set");
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                goto repeat;
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        }
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        mark_buffer_dirty(bh, 1);
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        j += i*8192 + sb->u.minix_sb.s_firstdatazone-1;
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        if (j < sb->u.minix_sb.s_firstdatazone ||
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            j >= sb->u.minix_sb.s_nzones)
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                return 0;
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        if (!(bh = getblk(sb->s_dev,j,BLOCK_SIZE))) {
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                printk("new_block: cannot get block");
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                return 0;
96
        }
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        memset(bh->b_data, 0, BLOCK_SIZE);
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        mark_buffer_uptodate(bh, 1);
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        mark_buffer_dirty(bh, 1);
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        brelse(bh);
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        return j;
102
}
103
 
104
unsigned long minix_count_free_blocks(struct super_block *sb)
105
{
106
        return (count_free(sb->u.minix_sb.s_zmap,sb->u.minix_sb.s_zmap_blocks)
107
                 << sb->u.minix_sb.s_log_zone_size);
108
}
109
 
110
static struct buffer_head *V1_minix_clear_inode(struct inode *inode)
111
{
112
        struct buffer_head *bh;
113
        struct minix_inode *raw_inode;
114
        int ino, block;
115
 
116
        ino = inode->i_ino;
117
        if (!ino || ino >= inode->i_sb->u.minix_sb.s_ninodes) {
118
                printk("Bad inode number on dev %s: %d is out of range\n",
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                       kdevname(inode->i_dev), ino);
120
                return 0;
121
        }
122
        block = (2 + inode->i_sb->u.minix_sb.s_imap_blocks +
123
                 inode->i_sb->u.minix_sb.s_zmap_blocks +
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                 (ino - 1) / MINIX_INODES_PER_BLOCK);
125
        bh = bread(inode->i_dev, block, BLOCK_SIZE);
126
        if (!bh) {
127
                printk("unable to read i-node block\n");
128
                return 0;
129
        }
130
        raw_inode = ((struct minix_inode *)bh->b_data +
131
                     (ino - 1) % MINIX_INODES_PER_BLOCK);
132
        raw_inode->i_nlinks = 0;
133
        raw_inode->i_mode = 0;
134
        mark_buffer_dirty(bh, 1);
135
        return bh;
136
}
137
 
138
static struct buffer_head *V2_minix_clear_inode(struct inode *inode)
139
{
140
        struct buffer_head *bh;
141
        struct minix2_inode *raw_inode;
142
        int ino, block;
143
 
144
        ino = inode->i_ino;
145
        if (!ino || ino >= inode->i_sb->u.minix_sb.s_ninodes) {
146
                printk("Bad inode number on dev %s: %d is out of range\n",
147
                       kdevname(inode->i_dev), ino);
148
                return 0;
149
        }
150
        block = (2 + inode->i_sb->u.minix_sb.s_imap_blocks +
151
                 inode->i_sb->u.minix_sb.s_zmap_blocks +
152
                 (ino - 1) / MINIX2_INODES_PER_BLOCK);
153
        bh = bread(inode->i_dev, block, BLOCK_SIZE);
154
        if (!bh) {
155
                printk("unable to read i-node block\n");
156
                return 0;
157
        }
158
        raw_inode = ((struct minix2_inode *) bh->b_data +
159
                     (ino - 1) % MINIX2_INODES_PER_BLOCK);
160
        raw_inode->i_nlinks = 0;
161
        raw_inode->i_mode = 0;
162
        mark_buffer_dirty(bh, 1);
163
        return bh;
164
}
165
 
166
/* Clear the link count and mode of a deleted inode on disk. */
167
 
168
static void minix_clear_inode(struct inode *inode)
169
{
170
        struct buffer_head *bh;
171
        if (INODE_VERSION(inode) == MINIX_V1)
172
                bh = V1_minix_clear_inode(inode);
173
        else
174
                bh = V2_minix_clear_inode(inode);
175
        brelse (bh);
176
}
177
 
178
void minix_free_inode(struct inode * inode)
179
{
180
        struct buffer_head * bh;
181
        unsigned long ino;
182
 
183
        if (!inode)
184
                return;
185
        if (!inode->i_dev) {
186
                printk("free_inode: inode has no device\n");
187
                return;
188
        }
189
        if (inode->i_count != 1) {
190
                printk("free_inode: inode has count=%ld\n",inode->i_count);
191
                return;
192
        }
193
        if (inode->i_nlink) {
194
                printk("free_inode: inode has nlink=%d\n",inode->i_nlink);
195
                return;
196
        }
197
        if (!inode->i_sb) {
198
                printk("free_inode: inode on nonexistent device\n");
199
                return;
200
        }
201
        if (inode->i_ino < 1 || inode->i_ino >= inode->i_sb->u.minix_sb.s_ninodes) {
202
                printk("free_inode: inode 0 or nonexistent inode\n");
203
                return;
204
        }
205
        ino = inode->i_ino;
206
        if (!(bh=inode->i_sb->u.minix_sb.s_imap[ino >> 13])) {
207
                printk("free_inode: nonexistent imap in superblock\n");
208
                return;
209
        }
210
        minix_clear_inode(inode);
211
        clear_inode(inode);
212
        if (!clear_bit(ino & 8191, bh->b_data))
213
                printk("free_inode: bit %lu already cleared.\n",ino);
214
        mark_buffer_dirty(bh, 1);
215
}
216
 
217
struct inode * minix_new_inode(const struct inode * dir)
218
{
219
        struct super_block * sb;
220
        struct inode * inode;
221
        struct buffer_head * bh;
222
        int i,j;
223
 
224
        if (!dir || !(inode = get_empty_inode()))
225
                return NULL;
226
        sb = dir->i_sb;
227
        inode->i_sb = sb;
228
        inode->i_flags = inode->i_sb->s_flags;
229
        j = 8192;
230
        for (i=0 ; i<8 ; i++)
231
                if ((bh = inode->i_sb->u.minix_sb.s_imap[i]) != NULL)
232
                        if ((j=find_first_zero_bit(bh->b_data, 8192)) < 8192)
233
                                break;
234
        if (!bh || j >= 8192) {
235
                iput(inode);
236
                return NULL;
237
        }
238
        if (set_bit(j,bh->b_data)) {    /* shouldn't happen */
239
                printk("new_inode: bit already set");
240
                iput(inode);
241
                return NULL;
242
        }
243
        mark_buffer_dirty(bh, 1);
244
        j += i*8192;
245
        if (!j || j >= inode->i_sb->u.minix_sb.s_ninodes) {
246
                iput(inode);
247
                return NULL;
248
        }
249
        inode->i_count = 1;
250
        inode->i_nlink = 1;
251
        inode->i_dev = sb->s_dev;
252
        inode->i_uid = current->fsuid;
253
        inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
254
        inode->i_dirt = 1;
255
        inode->i_ino = j;
256
        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
257
        inode->i_op = NULL;
258
        inode->i_blocks = inode->i_blksize = 0;
259
        insert_inode_hash(inode);
260
        return inode;
261
}
262
 
263
unsigned long minix_count_free_inodes(struct super_block *sb)
264
{
265
        return count_free(sb->u.minix_sb.s_imap,sb->u.minix_sb.s_imap_blocks);
266
}

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