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-rw-r--r--fs/minix/bitmap.c273
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..f4e5e5181
--- /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(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);
+}
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