This source file includes following definitions.
- count_used
- minix_free_block
- minix_new_block
- minix_count_free_blocks
- minix_free_inode
- minix_new_inode
- minix_count_free_inodes
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9 #include <linux/sched.h>
10 #include <linux/minix_fs.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13
14 #define clear_block(addr) \
15 __asm__("cld\n\t" \
16 "rep\n\t" \
17 "stosl" \
18 ::"a" (0),"c" (BLOCK_SIZE/4),"D" ((long) (addr)):"cx","di")
19
20 #define set_bit(nr,addr) ({\
21 char res; \
22 __asm__ __volatile__("btsl %1,%2\n\tsetb %0": \
23 "=q" (res):"r" (nr),"m" (*(addr))); \
24 res;})
25
26 #define clear_bit(nr,addr) ({\
27 char res; \
28 __asm__ __volatile__("btrl %1,%2\n\tsetnb %0": \
29 "=q" (res):"r" (nr),"m" (*(addr))); \
30 res;})
31
32 #define find_first_zero(addr) ({ \
33 int __res; \
34 __asm__("cld\n" \
35 "1:\tlodsl\n\t" \
36 "notl %%eax\n\t" \
37 "bsfl %%eax,%%edx\n\t" \
38 "jne 2f\n\t" \
39 "addl $32,%%ecx\n\t" \
40 "cmpl $8192,%%ecx\n\t" \
41 "jl 1b\n\t" \
42 "xorl %%edx,%%edx\n" \
43 "2:\taddl %%edx,%%ecx" \
44 :"=c" (__res):"0" (0),"S" (addr):"ax","dx","si"); \
45 __res;})
46
47 static int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
48
49 static unsigned long count_used(struct buffer_head *map[], unsigned numblocks,
50 unsigned numbits)
51 {
52 unsigned i, j, end, sum = 0;
53 struct buffer_head *bh;
54
55 for (i=0; (i<numblocks) && numbits; i++) {
56 if (!(bh=map[i]))
57 return(0);
58 if (numbits >= (8*BLOCK_SIZE)) {
59 end = BLOCK_SIZE;
60 numbits -= 8*BLOCK_SIZE;
61 } else {
62 int tmp;
63 end = numbits >> 3;
64 numbits &= 0x7;
65 tmp = bh->b_data[end] & ((1<<numbits)-1);
66 sum += nibblemap[tmp&0xf] + nibblemap[(tmp>>4)&0xf];
67 numbits = 0;
68 }
69 for (j=0; j<end; j++)
70 sum += nibblemap[bh->b_data[j] & 0xf]
71 + nibblemap[(bh->b_data[j]>>4)&0xf];
72 }
73 return(sum);
74 }
75
76 void minix_free_block(int dev, int block)
77 {
78 struct super_block * sb;
79 struct buffer_head * bh;
80 unsigned int bit,zone;
81
82 if (!(sb = get_super(dev))) {
83 printk("trying to free block on nonexistent device\n");
84 return;
85 }
86 if (block < sb->u.minix_sb.s_firstdatazone ||
87 block >= sb->u.minix_sb.s_nzones) {
88 printk("trying to free block not in datazone\n");
89 return;
90 }
91 bh = get_hash_table(dev,block,BLOCK_SIZE);
92 if (bh)
93 bh->b_dirt=0;
94 brelse(bh);
95 zone = block - sb->u.minix_sb.s_firstdatazone + 1;
96 bit = zone & 8191;
97 zone >>= 13;
98 bh = sb->u.minix_sb.s_zmap[zone];
99 if (!bh) {
100 printk("minix_free_block: nonexistent bitmap buffer\n");
101 return;
102 }
103 if (clear_bit(bit,bh->b_data))
104 printk("free_block (%04x:%d): bit already cleared\n",dev,block);
105 bh->b_dirt = 1;
106 return;
107 }
108
109 int minix_new_block(int dev)
110 {
111 struct buffer_head * bh;
112 struct super_block * sb;
113 int i,j;
114
115 if (!(sb = get_super(dev))) {
116 printk("trying to get new block from nonexistant device\n");
117 return 0;
118 }
119 repeat:
120 j = 8192;
121 for (i=0 ; i<8 ; i++)
122 if (bh=sb->u.minix_sb.s_zmap[i])
123 if ((j=find_first_zero(bh->b_data))<8192)
124 break;
125 if (i>=8 || !bh || j>=8192)
126 return 0;
127 if (set_bit(j,bh->b_data)) {
128 printk("new_block: bit already set");
129 goto repeat;
130 }
131 bh->b_dirt = 1;
132 j += i*8192 + sb->u.minix_sb.s_firstdatazone-1;
133 if (j >= sb->u.minix_sb.s_nzones)
134 return 0;
135 if (!(bh=getblk(dev,j,BLOCK_SIZE))) {
136 printk("new_block: cannot get block");
137 return 0;
138 }
139 if (bh->b_count != 1) {
140 printk("new block: count is != 1");
141 return 0;
142 }
143 clear_block(bh->b_data);
144 bh->b_uptodate = 1;
145 bh->b_dirt = 1;
146 brelse(bh);
147 return j;
148 }
149
150 unsigned long minix_count_free_blocks(struct super_block *sb)
151 {
152 return (sb->u.minix_sb.s_nzones - count_used(sb->u.minix_sb.s_zmap,sb->u.minix_sb.s_zmap_blocks,sb->u.minix_sb.s_nzones))
153 << sb->u.minix_sb.s_log_zone_size;
154 }
155
156 void minix_free_inode(struct inode * inode)
157 {
158 struct buffer_head * bh;
159
160 if (!inode)
161 return;
162 if (!inode->i_dev) {
163 memset(inode,0,sizeof(*inode));
164 return;
165 }
166 if (inode->i_count>1) {
167 printk("free_inode: inode has count=%d\n",inode->i_count);
168 return;
169 }
170 if (inode->i_nlink) {
171 printk("free_inode: inode has nlink=%d\n",inode->i_nlink);
172 return;
173 }
174 if (!inode->i_sb) {
175 printk("free_inode: inode on nonexistent device\n");
176 return;
177 }
178 if (inode->i_ino < 1 || inode->i_ino > inode->i_sb->u.minix_sb.s_ninodes) {
179 printk("free_inode: inode 0 or nonexistent inode\n");
180 return;
181 }
182 if (!(bh=inode->i_sb->u.minix_sb.s_imap[inode->i_ino>>13])) {
183 printk("free_inode: nonexistent imap in superblock\n");
184 return;
185 }
186 if (clear_bit(inode->i_ino&8191,bh->b_data))
187 printk("free_inode: bit already cleared.\n\r");
188 bh->b_dirt = 1;
189 memset(inode,0,sizeof(*inode));
190 }
191
192 struct inode * minix_new_inode(int dev)
193 {
194 struct inode * inode;
195 struct buffer_head * bh;
196 int i,j;
197
198 if (!(inode=get_empty_inode()))
199 return NULL;
200 if (!(inode->i_sb = get_super(dev))) {
201 printk("new_inode: unknown device\n");
202 iput(inode);
203 return NULL;
204 }
205 inode->i_flags = inode->i_sb->s_flags;
206 j = 8192;
207 for (i=0 ; i<8 ; i++)
208 if (bh=inode->i_sb->u.minix_sb.s_imap[i])
209 if ((j=find_first_zero(bh->b_data))<8192)
210 break;
211 if (!bh || j >= 8192 || j+i*8192 > inode->i_sb->u.minix_sb.s_ninodes) {
212 iput(inode);
213 return NULL;
214 }
215 if (set_bit(j,bh->b_data)) {
216 printk("new_inode: bit already set");
217 iput(inode);
218 return NULL;
219 }
220 bh->b_dirt = 1;
221 inode->i_count = 1;
222 inode->i_nlink = 1;
223 inode->i_dev = dev;
224 inode->i_uid = current->euid;
225 inode->i_gid = current->egid;
226 inode->i_dirt = 1;
227 inode->i_ino = j + i*8192;
228 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
229 inode->i_op = NULL;
230 inode->i_blocks = inode->i_blksize = 0;
231 return inode;
232 }
233
234 unsigned long minix_count_free_inodes(struct super_block *sb)
235 {
236 return sb->u.minix_sb.s_ninodes - count_used(sb->u.minix_sb.s_imap,sb->u.minix_sb.s_imap_blocks,sb->u.minix_sb.s_ninodes);
237 }