Had to wait for 'btrfs recover' to finish before I proceed farther.
Kernel is 4.19.45, tools are 4.19.1
File system is a 3-disk RAID10 with WD3003FZEX (WD Black 3TB)
Output from attempting to mount:
# mount -o ro,usebackuproot /dev/sdc1 /mnt
mount: wrong fs type, bad option, bad superblock on /dev/sdc1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
Kernel messages from the mount attempt:
[Thu Aug 15 08:47:42 2019] BTRFS info (device sdc1): trying to use backup root at mount time
[Thu Aug 15 08:47:42 2019] BTRFS info (device sdc1): disk space caching is enabled
[Thu Aug 15 08:47:42 2019] BTRFS info (device sdc1): has skinny extents
[Thu Aug 15 08:47:42 2019] BTRFS error (device sdc1): parent transid verify failed on 229846466560 wanted 49749 found 49750
[Thu Aug 15 08:47:42 2019] BTRFS error (device sdc1): parent transid verify failed on 229846466560 wanted 49749 found 49750
[Thu Aug 15 08:47:42 2019] BTRFS error (device sdc1): failed to read block groups: -5
[Thu Aug 15 08:47:42 2019] BTRFS error (device sdc1): open_ctree failed
Output from 'btrfs check -p /dev/sdc1':
# btrfs check -p /dev/sdc1
Opening filesystem to check...
parent transid verify failed on 229846466560 wanted 49749 found 49750
Ignoring transid failure
ERROR: child eb corrupted: parent bytenr=229845336064 item=0 parent level=1 child level=2
ERROR: cannot open file system
On 08/15/2019 10:35 +0800, Qu Wenruo wrote:
>>
>>
>> On 2019/8/15 ??????2:32, Tim Walberg wrote:
>> > Most of the recommendations I've found online deal with when "wanted" is
>> > greater than "found", which, if I understand correctly means that one or
>> > more transactions were interrupted/lost before fully committed.
>>
>> No matter what the case is, a proper transaction shouldn't have any tree
>> block overwritten.
>>
>> That means, either the FLUSH/FUA of the hardware/lower block layer is
>> screwed up, or the COW of tree block is already screwed up.
>>
>> >
>> > Are the recommendations for recovery the same if the system is reporting a
>> > "wanted" that is less than "found"?
>> >
>> The salvage is no difference than any transid mismatch, no matter if
>> it's larger or smaller.
>>
>> It depends on the tree block.
>>
>> Please provide full dmesg output and btrfs check for further advice.
>>
>> Thanks,
>> Qu
>>
--
+----------------------+
| Tim Walberg |
| 830 Carriage Dr. |
| Algonquin, IL 60102 |
| twalberg@xxxxxxxxxxx |
+----------------------+
