Re: extended attributes wiredness

[David Arendt <admin@prnet.org>]

Hi,

I have now tested a gentoo reinstall with a recompile of nfs-utils. By
observing how the directory /var/lib/nfs is created, I found a rather
simple way to reproduce the problem:

dd if=/dev/zero of=test.img bs=8192 count=81920
81920+0 records in
81920+0 records out
671088640 bytes (671 MB) copied, 1.52943 s, 439 MB/s

losetup /dev/loop0 test.img

mkfs.btrfs /dev/loop0

WARNING! - Btrfs v0.20-rc1-37-g91d9eec IS EXPERIMENTAL
WARNING! - see http://btrfs.wiki.kernel.org before using

SMALL VOLUME: forcing mixed metadata/data groups
Created a data/metadata chunk of size 8388608
fs created label (null) on /dev/loop0
    nodesize 4096 leafsize 4096 sectorsize 4096 size 640.00MB
Btrfs v0.20-rc1-37-g91d9eec

mount /dev/loop0 /mnt

btrfs subvolume create /mnt/test
Create subvolume '/mnt/test'

mkdir /mnt/test/test1

/root/x/testxattr /mnt/test/test1 
processing file /mnt/test/test1

cp -a /mnt/test/test1 /mnt/test/test2

/root/x/testxattr /mnt/test/test2
processing file /mnt/test/test2
processing attribute system.posix_acl_default
lgetxattr failed: No data available

Might it be a bug in coreutils ?

Thanks in advance,
David Arendt

On 11/27/12 08:46, Liu Bo wrote:
> Hi,  
>  
> (cc btrfs Mailing list to notify others.)
>
> Thanks for the helpful test.img.
>
> Well...after deeper debug, I'm sure that it's not a btrfs bug,
> at least not a btrfs acl/xattr bug. 
>  
> The debug tree shows 
>  
> item 10 key (257 INODE_ITEM 0) itemoff 3387 itemsize 160 
>         inode generation 6 transid 6 size 102 block group 0 mode 40755 links 1 
> item 11 key (257 INODE_REF 256) itemoff 3372 itemsize 15 
>         inode ref index 2 namelen 5 name: test1 
> item 12 key (257 XATTR_ITEM 367492571) itemoff 3318 itemsize 54 
>         location key (0 UNKNOWN.0 0) type 8 
>         namelen 24 datalen 0 name: system.posix_acl_default 
>                   ^^^^^^^^^^^ 
> item 13 key (257 XATTR_ITEM 2038346239) itemoff 3237 itemsize 81 
>         location key (0 UNKNOWN.0 0) type 8 
>         namelen 23 datalen 28 name: system.posix_acl_access 
>         data ^B 
>  
> ========== 
>
> so extended attribute "system.posix_acl_default" here has not data, which'll
> make filesystems(not just btrfs) return -ENODATA. 
>  
> I guess some userspace applications may make it like that. 
>  
> thanks, 
> liubo
>
> On Mon, Nov 26, 2012 at 06:38:06AM +0100, David Arendt wrote:
>> Hi,
>>
>> I don't know if your xattr patch was meant to fix this issue, but I have
>> just tested kernel 3.7-rc7 with your patch applied on another directory
>> having the problem and I still have the weird behaviour.
>>
>> Thanks in advance,
>> David Arendt