Re: btrfs-convert aborts with an assert

["Torbjörn Jansson" <torbjorn@jansson.tech>]

On 2022-06-06 16:31, Nikolay Borisov wrote:
> 
> 
> On 6.06.22 г. 17:03 ч., Torbjörn Jansson wrote:
>> Hello
>>
>> i tried to do a btrfs-convert of a ext4 filesystem and after a short while 
>> after starting it i was greeted with:
>>
>> # btrfs-convert /dev/xxxx
>> btrfs-convert from btrfs-progs v5.16.2
>>
>> convert/main.c:1162: do_convert: Assertion `cctx.total_bytes != 0` failed, 
>> value 0
>> btrfs-convert(+0xffb0)[0x557defdabfb0]
>> btrfs-convert(main+0x6c5)[0x557defdaa125]
>> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xea)[0x7f66e1f8bd0a]
>> btrfs-convert(_start+0x2a)[0x557defdab52a]
>> Aborted
>>
>> Any idea whats going on?
>> Is it a known bug?
>> Is the btrfs-progs that come with my dist too old?
>> FYI the ext4 filesystem is a bit large ~10tb of used data on it.
>>
>> I assume the convert didn't even start in this case and nothing was modified 
>> on the ext4 filesystem, correct? or?
>>
> 
> Care too run the following command and share the output:
> 
> echo "show_super_stats -h" | debugfs -f /dev/stdin /dev/loop0
> 
> change /dev/loop0 to wherever is your ext4 filesyste, however debugfs require 
> the fs to be unmounted.
> 

See output below.

one more thing, when i ran fsck.ext4 -f on the device before trying to run 
btrfs-convert it said things like:
Inode 61475702 extent tree (at level 1) could be shorter.  Optimize<y>? yes
Inode 61477092 extent tree (at level 2) could be narrower.  Optimize<y>? yes
and then a bunch more, all aditonal looked similar and said narrower.


Filesystem volume name:   <none>
Last mounted on:          /mnt/data
Filesystem UUID:          78b93577-0bb5-41a1-89d7-3027cf0b9bc2
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr dir_index filetype meta_bg 
extent 64bit flex_bg casefold sparse_super large_file huge_file dir_nlink 
extra_isize metadata_csum
Filesystem flags:         signed_directory_hash
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              536870912
Block count:              4294967296
Reserved block count:     0
Overhead clusters:        12982806
Free blocks:              2134612618
Free inodes:              536845192
First block:              0
Block size:               4096
Fragment size:            4096
Group descriptor size:    64
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         4096
Inode blocks per group:   256
First meta block group:   1792
Flex block group size:    16
Filesystem created:       Fri Aug 13 17:27:43 2021
Last mount time:          Sat May 21 13:56:20 2022
Last write time:          Mon Jun  6 15:33:45 2022
Mount count:              0
Maximum mount count:      -1
Last checked:             Mon Jun  6 15:33:45 2022
Check interval:           0 (<none>)
Lifetime writes:          93 TB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     32
Desired extra isize:      32
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      79d63f5e-1fd3-443f-ba05-1a90b7358160
Journal backup:           inode blocks
Checksum type:            crc32c
Checksum:                 0xb53baa13
Character encoding:       utf8-12.1
Directories:              138