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-rw-r--r--fs/qnx4/bitmap.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/fs/qnx4/bitmap.c b/fs/qnx4/bitmap.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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"
+
+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) {
+ int bytes = min(size - total, QNX4_BLOCK_SIZE);
+
+ if ((bh = sb_bread(sb, start + offset)) == NULL) {
+ printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
+ break;
+ }
+ total_free += bytes * BITS_PER_BYTE -
+ memweight(bh->b_data, bytes);
+ brelse(bh);
+ total += bytes;
+ offset++;
+ }
+
+ return total_free;
+}