Big endian machines (at least the one I have access to) cannot mount f2fs filesystems anymore. This is with Linux 4.14.89 but I suspect that 4.9.144 (and later) is affected as well.
commit 0cfe75c5b01199 ("f2fs: enhance sanity_check_raw_super() to avoid potential overflows") treats the "block_count" from struct f2fs_super_block as 32-bit little endian value instead of a 64-bit little endian value.
I tested this fix on top of Linux 4.14.49 but it seems that all stable and mainline kernel versions are affected: - 4.9.144 and later because 0cfe75c5b01199 was backported there - 4.14.86 and later because 0cfe75c5b01199 was backported there - 4.19 - 4.20-rcX
changes since v1 at [0]: - change the printk format for block_count from "%u" to "%llu" (thanks to "kbuild test robot" for spotting this) - added Chao Yu's reviewed by
[0] https://lore.kernel.org/patchwork/cover/1027285/
Martin Blumenstingl (1): f2fs: fix validation of the block count in sanity_check_raw_super
fs/f2fs/super.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
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 --- fs/f2fs/super.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index af58b2cc21b8..d3911d3f948b 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2496,10 +2496,10 @@ 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; }
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Martin Blumenstingl