ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

[J. Hart]

I am seeing the following error in one of a series of "btrfs send" 
operations.   The error is as follows:

At subvol /mnt/ArchPri/backup/primary/thinkcentre/root/backup.0.2
At snapshot backup.0.2017.04.21.03.11.40
ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

It looks like it might be a btrfs bug, but I'm not sure.

A similar (?) bug was reported back on Feb 27, 2015 in the following 
message:
https://www.spinics.net/lists/linux-btrfs/msg42278.html

The resulting thread has since moved to :
https://www.spinics.net/lists/linux-btrfs/thrd34.html#42278

I am currently using a custom built 4.10.0 kernel from kernel.org. The 
linux system it's running on is one I built entirely from source (not 
Linux From Scratch) using a set of procedures I designed and so is not a 
common commercial one.

I will be happy to provide whatever further information or diagnostics I 
can.

J. Hart

re: ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

[J. Hart]

I've got more information on the following error :

At subvol /mnt/ArchPri/backup/primary/thinkcentre/root/backup.0.2
At snapshot backup.0.2017.04.21.03.11.40
ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

I've filed a bug report with additional details at:

https://bugzilla.kernel.org/show_bug.cgi?id=195619

This error occurs during a series of "btrfs send" invocations.  It does 
not occur on all of them, but always at the same point in the operation, 
and so appears to be specific to (dependent on) the data being sent.

I have a test case down to the following:

su -
btrfs send --no-data temp/backup.0.2017.04.17.07.57.17 | btrfs rec temp/test
sync
btrfs send --no-data -p temp/backup.0.2017.04.17.07.57.17 
temp/backup.0.2017.04.21.03.11.40 | btrfs rec temp/test

The error should be something like:
At subvol temp/backup.0.2017.04.21.03.11.40
At snapshot backup.0.2017.04.21.03.11.40
ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

I will probably need to provide the data somehow, or at least the output 
from "btrfs send".  The original data is several GB in size.

J. Hart

Re: ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

[Filipe Manana]

On Mon, May 1, 2017 at 4:17 PM, J. Hart <jfhart085@gmail.com> wrote:
> I've got more information on the following error :
>
> At subvol /mnt/ArchPri/backup/primary/thinkcentre/root/backup.0.2
> At snapshot backup.0.2017.04.21.03.11.40
> ERROR: rename o3528-7220-0 -> usr failed: Directory not empty
>
> I've filed a bug report with additional details at:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=195619
>
> This error occurs during a series of "btrfs send" invocations.  It does not
> occur on all of them, but always at the same point in the operation, and so
> appears to be specific to (dependent on) the data being sent.
>
> I have a test case down to the following:
>
> su -
> btrfs send --no-data temp/backup.0.2017.04.17.07.57.17 | btrfs rec temp/test
> sync
> btrfs send --no-data -p temp/backup.0.2017.04.17.07.57.17
> temp/backup.0.2017.04.21.03.11.40 | btrfs rec temp/test
>
> The error should be something like:
> At subvol temp/backup.0.2017.04.21.03.11.40
> At snapshot backup.0.2017.04.21.03.11.40
> ERROR: rename o3528-7220-0 -> usr failed: Directory not empty
>
> I will probably need to provide the data somehow, or at least the output
> from "btrfs send".  The original data is several GB in size.

Just use "btrfs-image -c 9 /dev/whatever image_file", it will create a
compressed image where the data is replaced with zeroes (not needed to
debug this problem anyway). Then uploaded it anywhere convenient for
you.

Thanks.

>
>
> J. Hart
>
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Re: ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

[J. Hart]

On 05/01/2017 02:52 PM, Filipe Manana wrote:
> On Mon, May 1, 2017 at 4:17 PM, J. Hart <jfhart085@gmail.com> wrote:
> Just use "btrfs-image -c 9 /dev/whatever image_file", it will create a 
> compressed image where the data is replaced with zeroes (not needed to 
> debug this problem anyway). Then uploaded it anywhere convenient for you. 

I have prepared the image as per your instructions.  It is 27 Mb in 
size.  I have no way to confirm whether or not it is correct, as the 
documentation on how that might be done is unclear on that point. It was 
also not clear whether or not the btrfs filesystem should be unmounted 
as the documentation does not specify.   A warning appears if it is 
mounted, so I unmounted it to make the image.

I have at present no convenient location to upload it to.   Can you 
suggest one ?

If you can manage to load the image on to a btrfs filesystem, cd to the 
mount point and do the following:

btrfs se --no-data snp1 | btrfs rec temp
btrfs se --no-data -p snp1 snp2 | btrfs rec temp # failure here

The error should be something like:

-su-3.2# btrfs se --no-data -p snp1 snp2 | btrfs rec temp # failure here
At subvol snp2
At snapshot snp2
ERROR: rename o3528-12-0 -> usr failed: Directory not empty


I have been able to get the requisite data from the original filesystem 
to a completely different one, and recreate the error on the new 
filesystem, so the error seems to follow along with the data involved.

Re: ERROR: rename o3528-7220-0 -> usr failed: Directory not empty

[Filipe Manana]

On Tue, May 2, 2017 at 3:52 AM, J. Hart <jfhart085@gmail.com> wrote:
> On 05/01/2017 02:52 PM, Filipe Manana wrote:
>>
>> On Mon, May 1, 2017 at 4:17 PM, J. Hart <jfhart085@gmail.com> wrote:
>> Just use "btrfs-image -c 9 /dev/whatever image_file", it will create a
>> compressed image where the data is replaced with zeroes (not needed to debug
>> this problem anyway). Then uploaded it anywhere convenient for you.
>
>
> I have prepared the image as per your instructions.  It is 27 Mb in size.  I
> have no way to confirm whether or not it is correct, as the documentation on
> how that might be done is unclear on that point. It was also not clear
> whether or not the btrfs filesystem should be unmounted as the documentation
> does not specify.   A warning appears if it is mounted, so I unmounted it to
> make the image.
>
> I have at present no convenient location to upload it to.   Can you suggest
> one ?
>
> If you can manage to load the image on to a btrfs filesystem, cd to the
> mount point and do the following:
>
> btrfs se --no-data snp1 | btrfs rec temp
> btrfs se --no-data -p snp1 snp2 | btrfs rec temp # failure here
>
> The error should be something like:
>
> -su-3.2# btrfs se --no-data -p snp1 snp2 | btrfs rec temp # failure here
> At subvol snp2
> At snapshot snp2
> ERROR: rename o3528-12-0 -> usr failed: Directory not empty

So I managed to use the image and try it myself with the 4.11 kernel
codebase. No problems found sending those snapshots.
Please try a 4.11 kernel, as there's a few send fixes in there that
should fix the issue.

Thanks!

>
>
> I have been able to get the requisite data from the original filesystem to a
> completely different one, and recreate the error on the new filesystem, so
> the error seems to follow along with the data involved.
>