--- linux/fs/minix/bitmap.c	2018/04/24 18:07:17	1.1.1.2
+++ linux/fs/minix/bitmap.c	2018/04/24 18:10:48	1.1.1.4
@@ -1,12 +1,12 @@
 /*
- *  linux/fs/bitmap.c
+ *  linux/fs/minix/bitmap.c
  *
  *  (C) 1991  Linus Torvalds
  */
 
 /* bitmap.c contains the code that handles the inode and block bitmaps */
-#include <linux/string.h>
 
+#include <linux/string.h>
 #include <linux/sched.h>
 #include <linux/minix_fs.h>
 #include <linux/kernel.h>
@@ -44,6 +44,35 @@ __asm__("cld\n" \
 	:"=c" (__res):"0" (0),"S" (addr):"ax","dx","si"); \
 __res;})
 
+static int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
+
+static unsigned long count_used(struct buffer_head *map[], unsigned numblocks,
+	unsigned numbits)
+{
+	unsigned i, j, end, sum = 0;
+	struct buffer_head *bh;
+  
+	for (i=0; (i<numblocks) && numbits; i++) {
+		if (!(bh=map[i])) 
+			return(0);
+		if (numbits >= (8*BLOCK_SIZE)) { 
+			end = BLOCK_SIZE;
+			numbits -= 8*BLOCK_SIZE;
+		} else {
+			int tmp;
+			end = numbits >> 3;
+			numbits &= 0x7;
+			tmp = bh->b_data[end] & ((1<<numbits)-1);
+			sum += nibblemap[tmp&0xf] + nibblemap[(tmp>>4)&0xf];
+			numbits = 0;
+		}  
+		for (j=0; j<end; j++)
+			sum += nibblemap[bh->b_data[j] & 0xf] 
+				+ nibblemap[(bh->b_data[j]>>4)&0xf];
+	}
+	return(sum);
+}
+
 int minix_free_block(int dev, int block)
 {
 	struct super_block * sb;
@@ -107,6 +136,12 @@ int minix_new_block(int dev)
 	return j;
 }
 
+unsigned long minix_count_free_blocks(struct super_block *sb)
+{
+	return (sb->s_nzones - count_used(sb->s_zmap,sb->s_zmap_blocks,sb->s_nzones))
+		 << sb->s_log_zone_size;
+}
+
 void minix_free_inode(struct inode * inode)
 {
 	struct buffer_head * bh;
@@ -182,3 +217,8 @@ struct inode * minix_new_inode(int dev)
 	inode->i_op = NULL;
 	return inode;
 }
+
+unsigned long minix_count_free_inodes(struct super_block *sb)
+{
+	return sb->s_ninodes - count_used(sb->s_imap,sb->s_imap_blocks,sb->s_ninodes);
+}