Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 | /* * linux/fs/minix/bitmap.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* bitmap.c contains the code that handles the inode and block bitmaps */ #include <linux/sched.h> #include <linux/minix_fs.h> #include <linux/stat.h> #include <linux/kernel.h> #include <linux/string.h> #include <asm/bitops.h> static int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 }; static unsigned long count_used(struct buffer_head *map[], unsigned numblocks, unsigned numbits) { unsigned i, j, end, sum = 0; struct buffer_head *bh; for (i=0; (i<numblocks) && numbits; i++) { if (!(bh=map[i])) return(0); if (numbits >= (8*BLOCK_SIZE)) { end = BLOCK_SIZE; numbits -= 8*BLOCK_SIZE; } else { int tmp; end = numbits >> 3; numbits &= 0x7; tmp = bh->b_data[end] & ((1<<numbits)-1); sum += nibblemap[tmp&0xf] + nibblemap[(tmp>>4)&0xf]; numbits = 0; } for (j=0; j<end; j++) sum += nibblemap[bh->b_data[j] & 0xf] + nibblemap[(bh->b_data[j]>>4)&0xf]; } return(sum); } void minix_free_block(struct super_block * sb, int block) { struct buffer_head * bh; unsigned int bit,zone; if (!sb) { printk("trying to free block on nonexistent device\n"); return; } if (block < sb->u.minix_sb.s_firstdatazone || block >= sb->u.minix_sb.s_nzones) { printk("trying to free block not in datazone\n"); return; } bh = get_hash_table(sb->s_dev,block,BLOCK_SIZE); if (bh) bh->b_dirt=0; brelse(bh); zone = block - sb->u.minix_sb.s_firstdatazone + 1; bit = zone & 8191; zone >>= 13; bh = sb->u.minix_sb.s_zmap[zone]; if (!bh) { printk("minix_free_block: nonexistent bitmap buffer\n"); return; } if (!clear_bit(bit,bh->b_data)) printk("free_block (%04x:%d): bit already cleared\n",sb->s_dev,block); mark_buffer_dirty(bh, 1); return; } int minix_new_block(struct super_block * sb) { struct buffer_head * bh; int i,j; if (!sb) { printk("trying to get new block from nonexistent device\n"); return 0; } repeat: j = 8192; for (i=0 ; i<8 ; i++) if ((bh=sb->u.minix_sb.s_zmap[i]) != NULL) if ((j=find_first_zero_bit(bh->b_data, 8192)) < 8192) break; if (i>=8 || !bh || j>=8192) return 0; if (set_bit(j,bh->b_data)) { printk("new_block: bit already set"); goto repeat; } mark_buffer_dirty(bh, 1); j += i*8192 + sb->u.minix_sb.s_firstdatazone-1; if (j < sb->u.minix_sb.s_firstdatazone || j >= sb->u.minix_sb.s_nzones) return 0; if (!(bh = getblk(sb->s_dev,j,BLOCK_SIZE))) { printk("new_block: cannot get block"); return 0; } memset(bh->b_data, 0, BLOCK_SIZE); bh->b_uptodate = 1; mark_buffer_dirty(bh, 1); brelse(bh); return j; } unsigned long minix_count_free_blocks(struct super_block *sb) { 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)) << sb->u.minix_sb.s_log_zone_size; } void minix_free_inode(struct inode * inode) { struct buffer_head * bh; unsigned long ino; if (!inode) return; if (!inode->i_dev) { printk("free_inode: inode has no device\n"); return; } if (inode->i_count != 1) { printk("free_inode: inode has count=%d\n",inode->i_count); return; } if (inode->i_nlink) { printk("free_inode: inode has nlink=%d\n",inode->i_nlink); return; } if (!inode->i_sb) { printk("free_inode: inode on nonexistent device\n"); return; } if (inode->i_ino < 1 || inode->i_ino >= inode->i_sb->u.minix_sb.s_ninodes) { printk("free_inode: inode 0 or nonexistent inode\n"); return; } ino = inode->i_ino; if (!(bh=inode->i_sb->u.minix_sb.s_imap[ino >> 13])) { printk("free_inode: nonexistent imap in superblock\n"); return; } clear_inode(inode); if (!clear_bit(ino & 8191, bh->b_data)) printk("free_inode: bit %lu already cleared.\n",ino); mark_buffer_dirty(bh, 1); } struct inode * minix_new_inode(const struct inode * dir) { struct super_block * sb; struct inode * inode; struct buffer_head * bh; int i,j; if (!dir || !(inode = get_empty_inode())) return NULL; sb = dir->i_sb; inode->i_sb = sb; inode->i_flags = inode->i_sb->s_flags; j = 8192; for (i=0 ; i<8 ; i++) if ((bh = inode->i_sb->u.minix_sb.s_imap[i]) != NULL) if ((j=find_first_zero_bit(bh->b_data, 8192)) < 8192) break; if (!bh || j >= 8192) { iput(inode); return NULL; } if (set_bit(j,bh->b_data)) { /* shouldn't happen */ printk("new_inode: bit already set"); iput(inode); return NULL; } mark_buffer_dirty(bh, 1); j += i*8192; if (!j || j >= inode->i_sb->u.minix_sb.s_ninodes) { iput(inode); return NULL; } inode->i_count = 1; inode->i_nlink = 1; inode->i_dev = sb->s_dev; inode->i_uid = current->fsuid; inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; inode->i_dirt = 1; inode->i_ino = j; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_op = NULL; inode->i_blocks = inode->i_blksize = 0; insert_inode_hash(inode); return inode; } unsigned long minix_count_free_inodes(struct super_block *sb) { 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); } |