Re: recovering from "parent transid verify failed"

From: Tim Walberg <twalberg@comcast.net>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: Tim Walberg <twalberg@comcast.net>, linux-btrfs@vger.kernel.org
Subject: Re: recovering from "parent transid verify failed"
Date: Thu, 15 Aug 2019 08:55:58 -0500	[thread overview]
Message-ID: <20190815135558.GD2731@comcast.net> (raw)
In-Reply-To: <4be5086f-61e7-a108-8036-da7d7a5d5c11@gmx.com>

Also - here's 'btrfs inspect-internal dump-super /dev/sdc1':

superblock: bytenr=65536, device=/dev/sdc1
---------------------------------------------------------
csum_type   0 (crc32c)
csum_size   4
csum	  0x4331039b [match]
bytenr	    65536
flags	  0x1
      ( WRITTEN )
magic	  _BHRfS_M [match]
fsid	  53749823-faaf-46f9-866d-3778d93cb1ca
label	  btrfs1
generation    49750
root	  229846646784
sys_array_size	  129
chunk_root_generation 49725
root_level    1
chunk_root    2568857059328
chunk_root_level  1
log_root    0
log_root_transid  0
log_root_level	  0
total_bytes   9001775738880
bytes_used    2085801975808
sectorsize    4096
nodesize    16384
leafsize (deprecated)	16384
stripesize    4096
root_dir    6
num_devices   3
compat_flags	0x0
compat_ro_flags	  0x0
incompat_flags	  0x361
      ( MIXED_BACKREF |
        BIG_METADATA |
        EXTENDED_IREF |
        SKINNY_METADATA |
        NO_HOLES )
cache_generation  49748
uuid_tree_generation  49748
dev_item.uuid	7338a973-9a45-4032-a4c9-d18142fd7908
dev_item.fsid	53749823-faaf-46f9-866d-3778d93cb1ca [match]
dev_item.type	0
dev_item.total_bytes  3000591912960
dev_item.bytes_used 1407675531264
dev_item.io_align 4096
dev_item.io_width 4096
dev_item.sector_size  4096
dev_item.devid	  1
dev_item.dev_group  0
dev_item.seek_speed 0
dev_item.bandwidth  0
dev_item.generation 0

Although, 'btrfs inspect-internal logical-resolve ...' just says:

# btrfs inspect-internal logical-resolve 229846466560 /dev/sdc1
ERROR: not a btrfs filesystem: /dev/sdc1

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
>>	

End of included message

-- 
+----------------------+
| Tim Walberg          |
| 830 Carriage Dr.     |
| Algonquin, IL 60102  |
| twalberg@comcast.net |
+----------------------+