Linux-BTRFS Archive on lore.kernel.org
 help / color / Atom feed
From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: Pierre Abbat <phma@bezitopo.org>, linux-btrfs@vger.kernel.org
Subject: Re: Trying to mount hangs
Date: Fri, 22 May 2020 18:02:44 +0800
Message-ID: <f49ceced-fcbf-5be7-442d-25bbfbc75881@gmx.com> (raw)
In-Reply-To: <2582603.WkyslYimHe@puma>

[-- Attachment #1.1: Type: text/plain, Size: 1723 bytes --]



On 2020/5/22 下午5:40, Pierre Abbat wrote:
> On Thursday, May 21, 2020 9:32:54 PM EDT Qu Wenruo wrote:
>> Considering your btrfs check reports no serious problem, the hang looks
>> strange.
>>
>> The remaining possibility is the log tree.
>>
>> You could try to boot using any liveCD with new enough kernel, then
>> btrfs ins dump-super <device> | grep log_root
> 
> I can do that booted normally from the M.2. The output is
> log_root                862339072
> log_root_transid        0
> log_root_level          0
> 

So indeed log tree is involved.

>> If the result is not 0, then try btrfs rescue zero-log, then try mount
>> again.
> 
> You seem to be misunderstanding me. I'm not trying to fix the broken filesystem; 
> I already recovered the files to a new drive. I'm trying to give you enough 
> information to reproduce the hang in mount, so that you can fix the bug. If I 
> have to copy the entire filesystem to an external drive and ship it, I'll do 
> that, but I'm hoping that some smaller amount of data that I can upload in a 
> few hours would be sufficient.

For that purpose, we have btrfs-image, which will only dump the
metadata, which is way smaller than the full disk, and can be further
compressed using -c9 option. (And you can compress it furthermore).

That btrfs-image dump even contains log tree, which is exactly what we
need to fix the hang.

Thanks,
Qu

> 
> When I write a function that reads a file of a certain format, unless it's a 
> static file like a list of all primes less than 65536 with associated data, I 
> fuzz it so that, if it's given a file that's not exactly in that format, it 
> won't hang or crash.
> 
> Pierre
> 


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

  reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-21  1:34 Pierre Abbat
2020-05-21  7:56 ` Qu Wenruo
2020-05-21 23:48   ` Pierre Abbat
2020-05-22  1:32     ` Qu Wenruo
2020-05-22  9:40       ` Pierre Abbat
2020-05-22 10:02         ` Qu Wenruo [this message]
2020-05-24  6:37           ` Pierre Abbat
2020-05-24  9:24             ` Qu Wenruo
2020-05-24 12:10               ` Pierre Abbat
2020-05-24 12:32                 ` Qu Wenruo
2020-05-27 10:41 ` Qu Wenruo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=f49ceced-fcbf-5be7-442d-25bbfbc75881@gmx.com \
    --to=quwenruo.btrfs@gmx.com \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=phma@bezitopo.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-BTRFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-btrfs/0 linux-btrfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-btrfs linux-btrfs/ https://lore.kernel.org/linux-btrfs \
		linux-btrfs@vger.kernel.org
	public-inbox-index linux-btrfs

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-btrfs


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git