f2fs: large volume support

f2fs's cp has one page which consists of struct f2fs_checkpoint and
version bitmap of sit and nat. To support lots of segments, we need more
blocks for sit bitmap. So let's arrange sit bitmap as following:
+-----------------+------------+
| f2fs_checkpoint | sit bitmap |
| + nat bitmap    |            |
+-----------------+------------+
0                 4k        N blocks

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: simple code change for readability]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 676a2c6ccec7..9684b1f77a7d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -764,9 +764,18 @@ static inline unsigned long __bitmap_size(struct f2fs_sb_info *sbi, int flag)
 static inline void *__bitmap_ptr(struct f2fs_sb_info *sbi, int flag)
 {
         struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
-        int offset = (flag == NAT_BITMAP) ?
+        int offset;
+
+        if (le32_to_cpu(F2FS_RAW_SUPER(sbi)->cp_payload) > 0) {
+                if (flag == NAT_BITMAP)
+                        return &ckpt->sit_nat_version_bitmap;
+                else
+                        return ((unsigned char *)ckpt + F2FS_BLKSIZE);
+        } else {
+                offset = (flag == NAT_BITMAP) ?
                         le32_to_cpu(ckpt->sit_ver_bitmap_bytesize) : 0;
-        return &ckpt->sit_nat_version_bitmap + offset;
+                return &ckpt->sit_nat_version_bitmap + offset;
+        }
 }
 
 static inline block_t __start_cp_addr(struct f2fs_sb_info *sbi)