multiple btrfsck runs

multiple btrfsck runs

[Russell Coker]

Is it expected that running btrfsck more than once will keep reporting errors?

Below is the end of a btrfsck output when run the second time.

backpointer mismatch on [111942471680 32768]
owner ref check failed [111942471680 32768]
ref mismatch on [111942504448 40960] extent item 1, found 0
Incorrect local backref count on 111942504448 root 5 owner 160739 offset 
3440640 found 0 wanted 1 back 0x14331f48
backpointer mismatch on [111942504448 40960]
owner ref check failed [111942504448 40960]
Errors found in extent allocation tree
checking fs roots
root 5 inode 427603 errors 400
found 79658786895 bytes used err is 1
total csum bytes: 75604824
total tree bytes: 2109984768
total fs tree bytes: 1835044864
btree space waste bytes: 593880456
file data blocks allocated: 1065636474880
 referenced 133464895488
Btrfs Btrfs v0.19

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Re: multiple btrfsck runs

[cwillu]

On Sat, Mar 16, 2013 at 6:02 AM, Russell Coker <russell@coker.com.au> wrote:
> Is it expected that running btrfsck more than once will keep reporting errors?

Without options, btrfsck does not write to the disk.

Re: multiple btrfsck runs

[Marc MERLIN]

On Sat, Mar 16, 2013 at 06:24:47AM -0600, cwillu wrote:
> On Sat, Mar 16, 2013 at 6:02 AM, Russell Coker <russell@coker.com.au> wrote:
> > Is it expected that running btrfsck more than once will keep reporting errors?
> 
> Without options, btrfsck does not write to the disk.

Aaaaah, that explains why I never got it to work the day I wanted to try
it.
I should note that waht you're saying is neither documented in the man
page, nor in https://btrfs.wiki.kernel.org/index.php/Btrfsck

For that matter, the wiki actually states there are no options.

Is that mostly intentional so that whoever isn't reading the source
doesn't really run the tool because it's not ready?

Marc
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Re: multiple btrfsck runs

[cwillu]

On Sat, Mar 16, 2013 at 6:44 AM, Marc MERLIN <marc@merlins.org> wrote:
> On Sat, Mar 16, 2013 at 06:24:47AM -0600, cwillu wrote:
>> On Sat, Mar 16, 2013 at 6:02 AM, Russell Coker <russell@coker.com.au> wrote:
>> > Is it expected that running btrfsck more than once will keep reporting errors?
>>
>> Without options, btrfsck does not write to the disk.
>
> Aaaaah, that explains why I never got it to work the day I wanted to try
> it.
> I should note that waht you're saying is neither documented in the man
> page, nor in https://btrfs.wiki.kernel.org/index.php/Btrfsck
>
> For that matter, the wiki actually states there are no options.
>
> Is that mostly intentional so that whoever isn't reading the source
> doesn't really run the tool because it's not ready?

At least a bit, yeah.  People have getting better about updating the
documentation recently though.

Re: multiple btrfsck runs

[Russell Coker]

On Sat, 16 Mar 2013, cwillu <cwillu@cwillu.com> wrote:
> On Sat, Mar 16, 2013 at 6:02 AM, Russell Coker <russell@coker.com.au> wrote:
> > Is it expected that running btrfsck more than once will keep reporting
> > errors?
> 
> Without options, btrfsck does not write to the disk.

The man page for the version in Debian doesn't document any options.

The source indicates that --repair might be the one that's desired, is that 
correct?

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Re: multiple btrfsck runs

[cwillu]

On Sat, Mar 16, 2013 at 6:46 AM, Russell Coker <russell@coker.com.au> wrote:
> On Sat, 16 Mar 2013, cwillu <cwillu@cwillu.com> wrote:
>> On Sat, Mar 16, 2013 at 6:02 AM, Russell Coker <russell@coker.com.au> wrote:
>> > Is it expected that running btrfsck more than once will keep reporting
>> > errors?
>>
>> Without options, btrfsck does not write to the disk.
>
> The man page for the version in Debian doesn't document any options.
>
> The source indicates that --repair might be the one that's desired, is that
> correct?

Yes.  However, unless something is actually broken, or you've been
advised by a developer, I'd stick with btrfs scrub.

Re: multiple btrfsck runs

[Russell Coker]

On Sun, 17 Mar 2013, cwillu <cwillu@cwillu.com> wrote:
> On Sat, Mar 16, 2013 at 6:46 AM, Russell Coker <russell@coker.com.au> wrote:
> > On Sat, 16 Mar 2013, cwillu <cwillu@cwillu.com> wrote:
> >> On Sat, Mar 16, 2013 at 6:02 AM, Russell Coker <russell@coker.com.au> 
wrote:
> >> > Is it expected that running btrfsck more than once will keep reporting
> >> > errors?
> >> 
> >> Without options, btrfsck does not write to the disk.
> > 
> > The man page for the version in Debian doesn't document any options.
> > 
> > The source indicates that --repair might be the one that's desired, is
> > that correct?
> 
> Yes.  However, unless something is actually broken, or you've been
> advised by a developer, I'd stick with btrfs scrub.
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I've got a filesystem that causes a kernel panic and can't even get to the 
scrub stage, so btrfsck is necessary.

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=703211

While this is an upstream bug, I've filed the above Debian bug report about it.  
Sometimes in such situations the DD will fix the bug and send the patch 
upstream.

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