1 files changed, 273 insertions, 0 deletions
diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c
new file mode 100644
index 000000000..9115948c6
--- /dev/null
+++ b/fs/minix/bitmap.c
@@ -0,0 +1,273 @@
+// 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, 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 bits_per_zone = 8 * sb->s_blocksize;
+	unsigned long j;
+	int i;
+
+	if (!inode) {
+		*error = -ENOMEM;
+		return NULL;
+	}
+	j = bits_per_zone;
+	bh = NULL;
+	*error = -ENOSPC;
+	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 NULL;
+	}
+	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 NULL;
+	}
+	spin_unlock(&bitmap_lock);
+	mark_buffer_dirty(bh);
+	j += i * bits_per_zone;
+	if (!j || j > sbi->s_ninodes) {
+		iput(inode);
+		return NULL;
+	}
+	inode_init_owner(&init_user_ns, inode, dir, mode);
+	inode->i_ino = j;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	inode->i_blocks = 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 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);
+}