Re: fsck lowmem mode only: ERROR: errors found in fs roots

[Su Yue]

On 2018/11/2 10:10 PM, Christoph Anton Mitterer wrote:

Hey Su.

Sorry for the late reply cause I'm busy at other things.

Anything further I need to do in this matter or can I consider it
"solved" and you won't need further testing by my side, but just PR the
patches of that branch? :-)

I just looked through related codes and found the bug.
The patches can fix it. So no need to do more tests.
Thanks to your tests and patience. :)


In previous output of debug version, we can see @ret code
is 524296 which is (DIR_ITEM_MISMATCH(1 << 3) | DIR_INDEX_MISMATCH (1<<19)).

In btrfs-progs v4.17,
function check_inode_extref() passes u64 @mode as the last parameter
of find_dir_item();
However, find_dir_item() is defined as:
static int find_dir_item(struct btrfs_root *root, struct btrfs_key *key,
                         struct btrfs_key *location_key, char *name,
                         u32 namelen, u8 file_type);

The type of the last argument is u8 not u64.

So the case is that while checking files with inode_extrefs,
if (imode != file_type), then find_dir_item() thinks it found
DIR_ITEM_MISMATCH or DIR_INDEX_MISMATCH.

Thanks,
Su

Thanks,
Chris.

On Sat, 2018-10-27 at 14:15 +0200, Christoph Anton Mitterer wrote:

Hey.


Without the last patches on 4.17:

checking extents
checking free space cache
checking fs roots
ERROR: errors found in fs roots
Checking filesystem on /dev/mapper/system
UUID: 6050ca10-e778-4d08-80e7-6d27b9c89b3c
found 619543498752 bytes used, error(s) found
total csum bytes: 602382204
total tree bytes: 2534309888
total fs tree bytes: 1652097024
total extent tree bytes: 160432128
btree space waste bytes: 459291608
file data blocks allocated: 7334036647936
  referenced 730839187456


With the last patches, on 4.17:

checking extents
checking free space cache
checking fs roots
checking only csum items (without verifying data)
checking root refs
Checking filesystem on /dev/mapper/system
UUID: 6050ca10-e778-4d08-80e7-6d27b9c89b3c
found 619543498752 bytes used, no error found
total csum bytes: 602382204
total tree bytes: 2534309888
total fs tree bytes: 1652097024
total extent tree bytes: 160432128
btree space waste bytes: 459291608
file data blocks allocated: 7334036647936
  referenced 730839187456


Cheers,
Chris.