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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [fs/] [minix/] [bitmap.c] - Rev 1275
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/* * linux/fs/minix/bitmap.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * Modified for 680x0 by Hamish Macdonald * Fixed for 680x0 by Andreas Schwab */ /* bitmap.c contains the code that handles the inode and block bitmaps */ #include <linux/fs.h> #include <linux/minix_fs.h> #include <linux/locks.h> #include <asm/bitops.h> static int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 }; static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits) { unsigned i, j, sum = 0; struct buffer_head *bh; for (i=0; i<numblocks-1; i++) { if (!(bh=map[i])) return(0); for (j=0; j<BLOCK_SIZE; j++) sum += nibblemap[bh->b_data[j] & 0xf] + nibblemap[(bh->b_data[j]>>4) & 0xf]; } if (numblocks==0 || !(bh=map[numblocks-1])) return(0); i = ((numbits-(numblocks-1)*BLOCK_SIZE*8)/16)*2; for (j=0; j<i; j++) { sum += nibblemap[bh->b_data[j] & 0xf] + nibblemap[(bh->b_data[j]>>4) & 0xf]; } i = numbits%16; if (i!=0) { i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1); sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf]; sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf]; } return(sum); } void minix_free_block(struct inode * inode, int block) { struct super_block * sb = inode->i_sb; 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; } zone = block - sb->u.minix_sb.s_firstdatazone + 1; bit = zone & 8191; zone >>= 13; if (zone >= sb->u.minix_sb.s_zmap_blocks) { printk("minix_free_block: nonexistent bitmap buffer\n"); return; } bh = sb->u.minix_sb.s_zmap[zone]; if (!minix_test_and_clear_bit(bit,bh->b_data)) printk("free_block (%s:%d): bit already cleared\n", kdevname(sb->s_dev), block); mark_buffer_dirty(bh); return; } int minix_new_block(struct inode * inode) { struct super_block * sb = inode->i_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; bh = NULL; for (i = 0; i < sb->u.minix_sb.s_zmap_blocks; i++) { bh = sb->u.minix_sb.s_zmap[i]; if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) break; } if (!bh || j >= 8192) return 0; if (minix_test_and_set_bit(j,bh->b_data)) { printk("new_block: bit already set"); goto repeat; } mark_buffer_dirty(bh); 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; return j; } unsigned long minix_count_free_blocks(struct super_block *sb) { return (count_free(sb->u.minix_sb.s_zmap, sb->u.minix_sb.s_zmap_blocks, sb->u.minix_sb.s_nzones - sb->u.minix_sb.s_firstdatazone + 1) << sb->u.minix_sb.s_log_zone_size); } struct minix_inode * minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) { int block; struct minix_sb_info *sbi = &sb->u.minix_sb; struct minix_inode *p; if (!ino || ino > sbi->s_ninodes) { printk("Bad inode number on dev %s: %ld is out of range\n", bdevname(sb->s_dev), ino); return NULL; } ino--; block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + ino / MINIX_INODES_PER_BLOCK; *bh = sb_bread(sb, block); if (!*bh) { printk("unable to read i-node block\n"); return NULL; } p = (void *)(*bh)->b_data; return p + ino % MINIX_INODES_PER_BLOCK; } struct minix2_inode * minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh) { int block; struct minix_sb_info *sbi = &sb->u.minix_sb; struct minix2_inode *p; *bh = NULL; if (!ino || ino > sbi->s_ninodes) { printk("Bad inode number on dev %s: %ld is out of range\n", bdevname(sb->s_dev), ino); return NULL; } ino--; block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks + ino / MINIX2_INODES_PER_BLOCK; *bh = sb_bread(sb, block); if (!*bh) { printk("unable to read i-node block\n"); return NULL; } p = (void *)(*bh)->b_data; return p + ino % MINIX2_INODES_PER_BLOCK; } /* Clear the link count and mode of a deleted inode on disk. */ static void minix_clear_inode(struct inode *inode) { struct buffer_head *bh; if (INODE_VERSION(inode) == MINIX_V1) { struct minix_inode *raw_inode; raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh); if (raw_inode) { raw_inode->i_nlinks = 0; raw_inode->i_mode = 0; } } else { struct minix2_inode *raw_inode; raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh); if (raw_inode) { raw_inode->i_nlinks = 0; raw_inode->i_mode = 0; } } if (bh) { mark_buffer_dirty(bh); brelse (bh); } } void minix_free_inode(struct inode * inode) { struct buffer_head * bh; unsigned long ino; 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 ((ino >> 13) >= inode->i_sb->u.minix_sb.s_imap_blocks) { printk("free_inode: nonexistent imap in superblock\n"); return; } bh = inode->i_sb->u.minix_sb.s_imap[ino >> 13]; minix_clear_inode(inode); clear_inode(inode); if (!minix_test_and_clear_bit(ino & 8191, bh->b_data)) printk("free_inode: bit %lu already cleared.\n",ino); mark_buffer_dirty(bh); } struct inode * minix_new_inode(const struct inode * dir, int * error) { struct super_block * sb; struct inode * inode; struct buffer_head * bh; int i,j; sb = dir->i_sb; inode = new_inode(sb); if (!inode) { *error = -ENOMEM; return NULL; } j = 8192; bh = NULL; *error = -ENOSPC; lock_super(sb); for (i = 0; i < sb->u.minix_sb.s_imap_blocks; i++) { bh = inode->i_sb->u.minix_sb.s_imap[i]; if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) break; } if (!bh || j >= 8192) { iput(inode); unlock_super(sb); return NULL; } if (minix_test_and_set_bit(j,bh->b_data)) { /* shouldn't happen */ printk("new_inode: bit already set"); iput(inode); unlock_super(sb); return NULL; } mark_buffer_dirty(bh); j += i*8192; if (!j || j > inode->i_sb->u.minix_sb.s_ninodes) { iput(inode); unlock_super(sb); return NULL; } inode->i_uid = current->fsuid; inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; inode->i_ino = j; inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; inode->i_blocks = inode->i_blksize = 0; insert_inode_hash(inode); mark_inode_dirty(inode); unlock_super(sb); *error = 0; return inode; } unsigned long minix_count_free_inodes(struct super_block *sb) { return count_free(sb->u.minix_sb.s_imap, sb->u.minix_sb.s_imap_blocks, sb->u.minix_sb.s_ninodes + 1); }
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