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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270// SPDX-License-Identifier: GPL-2.0/* * 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/buffer_head.h>#include <linux/bitops.h>#include <linux/sched.h>
static DEFINE_SPINLOCK(bitmap_lock);
/* * bitmap consists of blocks filled with 16bit words * bit set == busy, bit clear == free * endianness is a mess, but for counting zero bits it really doesn't matter... */static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits){ __u32 sum = 0; unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
while (blocks--) { unsigned words = blocksize / 2; __u16 *p = (__u16 *)(*map++)->b_data; while (words--) sum += 16 - hweight16(*p++); }
return sum;}
void minix_free_block(struct inode *inode, unsigned long block){ struct super_block *sb = inode->i_sb; struct minix_sb_info *sbi = minix_sb(sb); struct buffer_head *bh; int k = sb->s_blocksize_bits + 3; unsigned long 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 & ((1<<k) - 1); zone >>= k; if (zone >= sbi->s_zmap_blocks) { printk("minix_free_block: nonexistent bitmap buffer\n"); return; } bh = sbi->s_zmap[zone]; spin_lock(&bitmap_lock); if (!minix_test_and_clear_bit(bit, bh->b_data)) printk("minix_free_block (%s:%lu): bit already cleared\n", sb->s_id, block); spin_unlock(&bitmap_lock); mark_buffer_dirty(bh); return;}
int minix_new_block(struct inode * inode){ struct minix_sb_info *sbi = minix_sb(inode->i_sb); int bits_per_zone = 8 * inode->i_sb->s_blocksize; int i;
for (i = 0; i < sbi->s_zmap_blocks; i++) { struct buffer_head *bh = sbi->s_zmap[i]; int j;
spin_lock(&bitmap_lock); j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); if (j < bits_per_zone) { minix_set_bit(j, bh->b_data); spin_unlock(&bitmap_lock); mark_buffer_dirty(bh); j += i * bits_per_zone + sbi->s_firstdatazone-1; if (j < sbi->s_firstdatazone || j >= sbi->s_nzones) break; return j; } spin_unlock(&bitmap_lock); } return 0;}
unsigned long minix_count_free_blocks(struct super_block *sb){ struct minix_sb_info *sbi = minix_sb(sb); u32 bits = sbi->s_nzones - sbi->s_firstdatazone + 1;
return (count_free(sbi->s_zmap, sb->s_blocksize, bits) << 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 inode 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; int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
*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 inode 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 super_block *sb = inode->i_sb; struct minix_sb_info *sbi = minix_sb(inode->i_sb); struct buffer_head *bh; int k = sb->s_blocksize_bits + 3; unsigned long ino, bit;
ino = inode->i_ino; if (ino < 1 || ino > sbi->s_ninodes) { printk("minix_free_inode: inode 0 or nonexistent inode\n"); return; } bit = ino & ((1<<k) - 1); ino >>= k; if (ino >= sbi->s_imap_blocks) { printk("minix_free_inode: nonexistent imap in superblock\n"); return; }
minix_clear_inode(inode); /* clear on-disk copy */
bh = sbi->s_imap[ino]; spin_lock(&bitmap_lock); if (!minix_test_and_clear_bit(bit, bh->b_data)) printk("minix_free_inode: bit %lu already cleared\n", bit); spin_unlock(&bitmap_lock); mark_buffer_dirty(bh);}
struct inode *minix_new_inode(const struct inode *dir, umode_t mode){ 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 bits_per_zone = 8 * sb->s_blocksize; unsigned long j; int i;
if (!inode) return ERR_PTR(-ENOMEM); j = bits_per_zone; bh = NULL; spin_lock(&bitmap_lock); for (i = 0; i < sbi->s_imap_blocks; i++) { bh = sbi->s_imap[i]; j = minix_find_first_zero_bit(bh->b_data, bits_per_zone); if (j < bits_per_zone) break; } if (!bh || j >= bits_per_zone) { spin_unlock(&bitmap_lock); iput(inode); return ERR_PTR(-ENOSPC); } if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */ spin_unlock(&bitmap_lock); printk("minix_new_inode: bit already set\n"); iput(inode); return ERR_PTR(-ENOSPC); } spin_unlock(&bitmap_lock); mark_buffer_dirty(bh); j += i * bits_per_zone; if (!j || j > sbi->s_ninodes) { iput(inode); return ERR_PTR(-EFSCORRUPTED); } inode_init_owner(&nop_mnt_idmap, inode, dir, mode); inode->i_ino = j; simple_inode_init_ts(inode); inode->i_blocks = 0; memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u)); insert_inode_hash(inode); mark_inode_dirty(inode);
return inode;}
unsigned long minix_count_free_inodes(struct super_block *sb){ struct minix_sb_info *sbi = minix_sb(sb); u32 bits = sbi->s_ninodes + 1;
return count_free(sbi->s_imap, sb->s_blocksize, bits);}