Excerpts from Johannes Hirte's message of 2011-02-23 18:02:44 -0500:

On Wednesday 23 February 2011 22:56:27 Chris Mason wrote:

quoted

Excerpts from Zhong, Xin's message of 2011-02-23 02:27:05 -0500:

quoted

In the dmesg of rc4, I can see svn hang in shrink_dellalloc and there's
two flush-btrfs threads hang there too.

Josef, it seems you are the expert in this area. Could you take a quick
look? Thanks!

Ok, it does look like the fluhs-btrfs threads are busy trying to flush
things.

Could you please do a btrfs-show and a btrfs fi df /xxx (where xxx is
your mount point) and send the results here?

-chris

failed to read /dev/sr0
Label: none  uuid: 00eab15f-c4cf-4403-a529-9bc11fa50167
        Total devices 1 FS bytes used 47.72GB
        devid    1 size 65.69GB used 65.69GB path /dev/sda2

Label: none  uuid: c6f4e6e6-c4ba-4394-9e9c-bbc3d0b32793
        Total devices 1 FS bytes used 9.48GB
        devid    1 size 20.01GB used 20.01GB path /dev/sda1

Btrfs v0.19-35-g1b444cd-dirty

and btrfs fi df on

/

Data: total=15.49GB, used=8.35GB
System, DUP: total=8.00MB, used=12.00KB
System: total=4.00MB, used=0.00
Metadata, DUP: total=2.25GB, used=1.13GB

/home

Data: total=63.42GB, used=47.47GB
System: total=4.00MB, used=16.00KB
Metadata: total=2.27GB, used=251.34MB

The bug is reproducable on both filesystems.

Ok, you've got a good amount of metadata space free, but it is
frantically trying to make room for the delayed allocation.  Let me see
if I can recreate this setup here.

-chris