1 files changed, 58 insertions, 0 deletions
diff --git a/fs/qnx4/bitmap.c b/fs/qnx4/bitmap.c
new file mode 100644
index 00000000..22e0d60e
--- /dev/null
+++ b/fs/qnx4/bitmap.c
@@ -0,0 +1,58 @@
+/*
+ * QNX4 file system, Linux implementation.
+ *
+ * Version : 0.2.1
+ *
+ * Using parts of the xiafs filesystem.
+ *
+ * History :
+ *
+ * 28-05-1998 by Richard Frowijn : first release.
+ * 20-06-1998 by Frank Denis : basic optimisations.
+ * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
+ * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/bitops.h>
+#include "qnx4.h"
+
+static void count_bits(register const char *bmPart, register int size,
+		       int *const tf)
+{
+	char b;
+	int tot = *tf;
+
+	if (size > QNX4_BLOCK_SIZE) {
+		size = QNX4_BLOCK_SIZE;
+	}
+	do {
+		b = *bmPart++;
+		tot += 8 - hweight8(b);
+		size--;
+	} while (size != 0);
+	*tf = tot;
+}
+
+unsigned long qnx4_count_free_blocks(struct super_block *sb)
+{
+	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
+	int total = 0;
+	int total_free = 0;
+	int offset = 0;
+	int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
+	struct buffer_head *bh;
+
+	while (total < size) {
+		if ((bh = sb_bread(sb, start + offset)) == NULL) {
+			printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
+			break;
+		}
+		count_bits(bh->b_data, size - total, &total_free);
+		brelse(bh);
+		total += QNX4_BLOCK_SIZE;
+		offset++;
+	}
+
+	return total_free;
+}