Re: interest in post-mortem examination of a BTRFS system and improving the btrfs-code?

["Nik." <btrfs@avgustinov.eu>]

2019-04-05 10:15, Qu Wenruo:
> 
> 
> On 2019/4/5 下午3:41, Nik. wrote:
>>
>> Below is the stderr of both commands:
>>
>> # btrfs inspect dump-tree -t chunk /dev/md0>DT-chunk.log
>> # btrfs inspect dump-tree -t extent /dev/md0>DT-extent.log
>> ERROR: leaf 1894009225216 slot 30 pointer invalid, offset 146038 size 37
>> leaf data limit 16283
>> ERROR: skip remaining slots
>>
>> Since the output on stdout is pretty long even after gzip, I am
>> providing only the output of the first command as attachment. The output
>> of the second command (25 MB after gzip -9) can be downloaded here:
>>
>> https://cloud.avgustinov.eu/index.php/s/AgbwWyCrbYjenq8
> 
> Sorry, I should have use a more specific command to get a smaller output.
> But anyway, your output is good enough for me to craft the fix patch.
> 
> Here is the dirty fix branch:
> https://github.com/adam900710/btrfs-progs/tree/dirty_fix_for_nik
> 
> Compile the btrfs-progs as usual.
> Just a late hint, you can disable document/btrfs-convert to reduce the
> dependency:
> $ ./configure --disable-documentation --disable-convert
> 
> Then, inside btrfs-progs directory, call:
> # ./btrfs-corrupt-block -X /dev/md0
incorrect offsets 15003 146075
Open ctree failed

Actually there was one warning during make, I don't know of it is relevant:
     [CC]     check/main.o
check/main.c: In function ‘try_repair_inode’:
check/main.c:2688:5: warning: ‘ret’ may be used uninitialized in this 
function [-Wmaybe-uninitialized]
   if (!ret) {
      ^
check/main.c:2666:6: note: ‘ret’ was declared here
   int ret;
       ^~~

The previous steps were as follow (output ommited, since nothing 
unexpected happened):
#git clone --single-branch -v -b dirty_fix_for_nik 
https://github.com/adam900710/btrfs-progs.git
#cd btrfs-progs/
#./autogen.sh
#./configure --disable-documentation --disable-convert
#make

Did I got the right branch? Or miss any step?

Kind regards,
Nik.
--

> If everything goes correctly, it should output something like:
>    Successfully repaired tree block at 1894009225216
> (And please ignore any grammar error in my code)
> 
> After that, please run a "btrfs check --readonly" to ensure no other bit
> flip in your fs.
> 
> Thanks,
> Qu
> 
> 
> 
>>
>> Hope this is ok.
>>
>> Regards,
>> Nik.
>> -
>