On Mon, Jan 09, 2012 at 01:50:34AM -0500, Marios Titas wrote:

I tried this for many different scenarios and it seems to work pretty
well. I only ran into one problematic case: If you remove a device
from a multidevice filesystem it crashes. Here's how to reproduce it:

truncate -s1g /tmp/test1
truncate -s1g /tmp/test2
losetup /dev/loop1 /tmp/test1
losetup /dev/loop2 /tmp/test2
mkdir /tmp/test
./mkfs.btrfs -L test -d single -m single /dev/loop1 /dev/loop2
mount -o noatime /dev/loop1 /tmp/test
./btrfs dev del /dev/loop1 /tmp/test
./btrfs fi bal start /tmp/test

There is no actual restriping involved but the above example does work
corretly under 3.1+for-linus whereas it fails with your patches.

Thanks for your testing.  The good news is that I put that BUG() there
simply for debugging so it's nothing major:

2520                    if (ret)
2521                            BUG(); /* FIXME break ? */

It used to be just a break out of the loop there, so that's the reason
it doesn't panic with 3.1+for-linus.  I'll investigate further and fix
this.

Thanks,

		Ilya