--- Begin Message ---
Subject: |
cp (8.10) sparse handling fails on compressed btrfs (cp/fiemap-2) |
Date: |
Mon, 7 Feb 2011 22:53:26 -0500 |
User-agent: |
KMail/1.13.5 (Linux/2.6.37; KDE/4.5.5; x86_64; ; ) |
after upgrading from coreutils 8.9 to 8.10, the sparse handling in cp is
silently breaking on btrfs filesystems with the compressed option enabled.
using --sparse=never works fine, but "auto" or "always" tend to fail. the
cp/fiemap-2 test catches the issue nicely.
to reproduce (i'm using linux-2.6.37):
file=btrfs.img
mntp=/mnt/tmp/
dd if=/dev/zero of=$file bs=1M count=0 seek=1024
mkfs.btrfs $file
mount -t btrfs -o compress $file $mntp
cd $mntp
tar xf ~/coreutils-8.10.tar.xz
cd coreutils-8.10/tests
./cp/fiemap-2
and this last test shows:
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/loop0 btrfs 1048576 20420 377028 6% /mnt/tmp
0+0 records in
0+0 records out
0 bytes (0 B) copied, 2.7598e-05 s, 0.0 kB/s
k k2 differ: byte 1, line 1
255+0 records in
255+0 records out
261120 bytes (261 kB) copied, 0.00310926 s, 84.0 MB/s
-mike
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--- Begin Message ---
Subject: |
Re: bug#8001: cp (8.10) sparse handling fails on compressed btrfs (cp/fiemap-2) |
Date: |
Wed, 23 Feb 2011 09:49:55 +0000 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 |
On 23/02/11 03:31, Chris Mason wrote:
> I've got a fix for this on the btrfs side in testing. It is definitely
> a btrfs bug.
[resend]
Cool.
I'm closing this ticket, so.
Interesting I didn't notice this with kernel-2.6.38-0.rc4.git0.2.fc15.i686
(with a 1G loop back BTRFS on ext4)
I'd appreciate a link to the fix at some stage.
If we know what's going on exactly we might be
able to know how widespread the issue is and
whether we could work around it in `cp`.
cheers,
Pádraig.
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