From 2a5f4e990fd0388e48c9460a2280d447db6e2abb Mon Sep 17 00:00:00 2001
From: pumnflqv2 <ggdxz77@163.com>
Date: Tue, 5 Jul 2022 04:26:24 +0800
Subject: [PATCH] ADD file via upload

---
 0/linux/fs/bitmap.c | 168 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 0/linux/fs/bitmap.c

diff --git a/0/linux/fs/bitmap.c b/0/linux/fs/bitmap.c
new file mode 100644
index 0000000..73951a8
--- /dev/null
+++ b/0/linux/fs/bitmap.c
@@ -0,0 +1,168 @@
+/*
+ *  linux/fs/bitmap.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+/* bitmap.c contains the code that handles the inode and block bitmaps */
+#include <string.h>
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+
+#define clear_block(addr) \
+__asm__ __volatile__ ("cld\n\t" \
+	"rep\n\t" \
+	"stosl" \
+	::"a" (0),"c" (BLOCK_SIZE/4),"D" ((long) (addr)))
+
+#define set_bit(nr,addr) ({\
+register int res __asm__("ax"); \
+__asm__ __volatile__("btsl %2,%3\n\tsetb %%al": \
+"=a" (res):"0" (0),"r" (nr),"m" (*(addr))); \
+res;})
+
+#define clear_bit(nr,addr) ({\
+register int res __asm__("ax"); \
+__asm__ __volatile__("btrl %2,%3\n\tsetnb %%al": \
+"=a" (res):"0" (0),"r" (nr),"m" (*(addr))); \
+res;})
+
+#define find_first_zero(addr) ({ \
+int __res; \
+__asm__ __volatile__ ("cld\n" \
+	"1:\tlodsl\n\t" \
+	"notl %%eax\n\t" \
+	"bsfl %%eax,%%edx\n\t" \
+	"je 2f\n\t" \
+	"addl %%edx,%%ecx\n\t" \
+	"jmp 3f\n" \
+	"2:\taddl $32,%%ecx\n\t" \
+	"cmpl $8192,%%ecx\n\t" \
+	"jl 1b\n" \
+	"3:" \
+	:"=c" (__res):"c" (0),"S" (addr)); \
+__res;})
+
+void free_block(int dev, int block)
+{
+	struct super_block * sb;
+	struct buffer_head * bh;
+
+	if (!(sb = get_super(dev)))
+		panic("trying to free block on nonexistent device");
+	if (block < sb->s_firstdatazone || block >= sb->s_nzones)
+		panic("trying to free block not in datazone");
+	bh = get_hash_table(dev,block);
+	if (bh) {
+		if (bh->b_count != 1) {
+			printk("trying to free block (%04x:%d), count=%d\n",
+				dev,block,bh->b_count);
+			return;
+		}
+		bh->b_dirt=0;
+		bh->b_uptodate=0;
+		brelse(bh);
+	}
+	block -= sb->s_firstdatazone - 1 ;
+	if (clear_bit(block&8191,sb->s_zmap[block/8192]->b_data)) {
+		printk("block (%04x:%d) ",dev,block+sb->s_firstdatazone-1);
+		panic("free_block: bit already cleared");
+	}
+	sb->s_zmap[block/8192]->b_dirt = 1;
+}
+
+int new_block(int dev)
+{
+	struct buffer_head * bh;
+	struct super_block * sb;
+	int i,j;
+
+	if (!(sb = get_super(dev)))
+		panic("trying to get new block from nonexistant device");
+	j = 8192;
+	for (i=0 ; i<8 ; i++)
+		if (bh=sb->s_zmap[i])
+			if ((j=find_first_zero(bh->b_data))<8192)
+				break;
+	if (i>=8 || !bh || j>=8192)
+		return 0;
+	if (set_bit(j,bh->b_data))
+		panic("new_block: bit already set");
+	bh->b_dirt = 1;
+	j += i*8192 + sb->s_firstdatazone-1;
+	if (j >= sb->s_nzones)
+		return 0;
+	if (!(bh=getblk(dev,j)))
+		panic("new_block: cannot get block");
+	if (bh->b_count != 1)
+		panic("new block: count is != 1");
+	clear_block(bh->b_data);
+	bh->b_uptodate = 1;
+	bh->b_dirt = 1;
+	brelse(bh);
+	return j;
+}
+
+void free_inode(struct m_inode * inode)
+{
+	struct super_block * sb;
+	struct buffer_head * bh;
+
+	if (!inode)
+		return;
+	if (!inode->i_dev) {
+		memset(inode,0,sizeof(*inode));
+		return;
+	}
+	if (inode->i_count>1) {
+		printk("trying to free inode with count=%d\n",inode->i_count);
+		panic("free_inode");
+	}
+	if (inode->i_nlinks)
+		panic("trying to free inode with links");
+	if (!(sb = get_super(inode->i_dev)))
+		panic("trying to free inode on nonexistent device");
+	if (inode->i_num < 1 || inode->i_num > sb->s_ninodes)
+		panic("trying to free inode 0 or nonexistant inode");
+	if (!(bh=sb->s_imap[inode->i_num>>13]))
+		panic("nonexistent imap in superblock");
+	if (clear_bit(inode->i_num&8191,bh->b_data))
+		printk("free_inode: bit already cleared.\n\r");
+	bh->b_dirt = 1;
+	memset(inode,0,sizeof(*inode));
+}
+
+struct m_inode * new_inode(int dev)
+{
+	struct m_inode * inode;
+	struct super_block * sb;
+	struct buffer_head * bh;
+	int i,j;
+
+	if (!(inode=get_empty_inode()))
+		return NULL;
+	if (!(sb = get_super(dev)))
+		panic("new_inode with unknown device");
+	j = 8192;
+	for (i=0 ; i<8 ; i++)
+		if (bh=sb->s_imap[i])
+			if ((j=find_first_zero(bh->b_data))<8192)
+				break;
+	if (!bh || j >= 8192 || j+i*8192 > sb->s_ninodes) {
+		iput(inode);
+		return NULL;
+	}
+	if (set_bit(j,bh->b_data))
+		panic("new_inode: bit already set");
+	bh->b_dirt = 1;
+	inode->i_count=1;
+	inode->i_nlinks=1;
+	inode->i_dev=dev;
+	inode->i_uid=current->euid;
+	inode->i_gid=current->egid;
+	inode->i_dirt=1;
+	inode->i_num = j + i*8192;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+	return inode;
+}