f2fs: fix validation of the block count in sanity_check_raw_super

commit 88960068f25fcc3759455d85460234dcc9d43fef upstream.

Treat "block_count" from struct f2fs_super_block as 64-bit little endian
value in sanity_check_raw_super() because struct f2fs_super_block
declares "block_count" as "__le64".

This fixes a bug where the superblock validation fails on big endian
devices with the following error:
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 1th superblock
  F2FS-fs (sda1): Wrong segment_count / block_count (61439 > 0)
  F2FS-fs (sda1): Can't find valid F2FS filesystem in 2th superblock
As result of this the partition cannot be mounted.

With this patch applied the superblock validation works fine and the
partition can be mounted again:
  F2FS-fs (sda1): Mounted with checkpoint version = 7c84

My little endian x86-64 hardware was able to mount the partition without
this fix.
To confirm that mounting f2fs filesystems works on big endian machines
again I tested this on a 32-bit MIPS big endian (lantiq) device.

Fixes: 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid potential overflows")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index c8f408d8a5824bde3500e07f01d7fb5e71b8632d..83a96334dc072a9b7f66a768812c6070c2f7cb5e 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1427,10 +1427,10 @@ static int sanity_check_raw_super(struct f2fs_sb_info *sbi,
                return 1;
        }
 
-       if (segment_count > (le32_to_cpu(raw_super->block_count) >> 9)) {
+       if (segment_count > (le64_to_cpu(raw_super->block_count) >> 9)) {
                f2fs_msg(sb, KERN_INFO,
-                       "Wrong segment_count / block_count (%u > %u)",
-                       segment_count, le32_to_cpu(raw_super->block_count));
+                       "Wrong segment_count / block_count (%u > %llu)",
+                       segment_count, le64_to_cpu(raw_super->block_count));
                return 1;
        }