diff options
Diffstat (limited to 'fs/minix/bitmap.c')
| -rw-r--r-- | fs/minix/bitmap.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c new file mode 100644 index 000000000000..dc6a4e4abcdc --- /dev/null +++ b/fs/minix/bitmap.c @@ -0,0 +1,269 @@ +/* + * 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 "minix.h" +#include <linux/smp_lock.h> +#include <linux/buffer_head.h> +#include <linux/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 minix_sb_info * sbi = minix_sb(sb); + struct buffer_head * bh; + unsigned int bit,zone; + + if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) { + printk("trying to free block not in datazone\n"); + return; + } + zone = block - sbi->s_firstdatazone + 1; + bit = zone & 8191; + zone >>= 13; + if (zone >= sbi->s_zmap_blocks) { + printk("minix_free_block: nonexistent bitmap buffer\n"); + return; + } + bh = sbi->s_zmap[zone]; + lock_kernel(); + if (!minix_test_and_clear_bit(bit,bh->b_data)) + printk("free_block (%s:%d): bit already cleared\n", + sb->s_id, block); + unlock_kernel(); + mark_buffer_dirty(bh); + return; +} + +int minix_new_block(struct inode * inode) +{ + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + int i; + + for (i = 0; i < sbi->s_zmap_blocks; i++) { + struct buffer_head *bh = sbi->s_zmap[i]; + int j; + + lock_kernel(); + if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) { + minix_set_bit(j,bh->b_data); + unlock_kernel(); + mark_buffer_dirty(bh); + j += i*8192 + sbi->s_firstdatazone-1; + if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) + break; + return j; + } + unlock_kernel(); + } + return 0; +} + +unsigned long minix_count_free_blocks(struct minix_sb_info *sbi) +{ + return (count_free(sbi->s_zmap, sbi->s_zmap_blocks, + sbi->s_nzones - sbi->s_firstdatazone + 1) + << sbi->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 = minix_sb(sb); + struct minix_inode *p; + + if (!ino || ino > sbi->s_ninodes) { + printk("Bad inode number on dev %s: %ld is out of range\n", + sb->s_id, (long)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 = minix_sb(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", + sb->s_id, (long)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 = NULL; + + 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 minix_sb_info *sbi = minix_sb(inode->i_sb); + struct buffer_head * bh; + unsigned long ino; + + ino = inode->i_ino; + if (ino < 1 || ino > sbi->s_ninodes) { + printk("minix_free_inode: inode 0 or nonexistent inode\n"); + goto out; + } + if ((ino >> 13) >= sbi->s_imap_blocks) { + printk("minix_free_inode: nonexistent imap in superblock\n"); + goto out; + } + + minix_clear_inode(inode); /* clear on-disk copy */ + + bh = sbi->s_imap[ino >> 13]; + lock_kernel(); + if (!minix_test_and_clear_bit(ino & 8191, bh->b_data)) + printk("minix_free_inode: bit %lu already cleared.\n", ino); + unlock_kernel(); + mark_buffer_dirty(bh); + out: + clear_inode(inode); /* clear in-memory copy */ +} + +struct inode * minix_new_inode(const struct inode * dir, int * error) +{ + struct super_block *sb = dir->i_sb; + struct minix_sb_info *sbi = minix_sb(sb); + struct inode *inode = new_inode(sb); + struct buffer_head * bh; + int i,j; + + if (!inode) { + *error = -ENOMEM; + return NULL; + } + j = 8192; + bh = NULL; + *error = -ENOSPC; + lock_kernel(); + for (i = 0; i < sbi->s_imap_blocks; i++) { + bh = sbi->s_imap[i]; + if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) + break; + } + if (!bh || j >= 8192) { + unlock_kernel(); + iput(inode); + return NULL; + } + if (minix_test_and_set_bit(j,bh->b_data)) { /* shouldn't happen */ + printk("new_inode: bit already set"); + unlock_kernel(); + iput(inode); + return NULL; + } + unlock_kernel(); + mark_buffer_dirty(bh); + j += i*8192; + if (!j || j > sbi->s_ninodes) { + iput(inode); + 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_SEC; + inode->i_blocks = inode->i_blksize = 0; + memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); + insert_inode_hash(inode); + mark_inode_dirty(inode); + + *error = 0; + return inode; +} + +unsigned long minix_count_free_inodes(struct minix_sb_info *sbi) +{ + return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1); +} |