Re: [PATCH 2/6] btrfs: try to reclaim some space when chunk allocation fails

[Josef Bacik <josef@redhat.com>]

On Wed, Dec 22, 2010 at 06:47:20PM +0800, Miao Xie wrote:
> We cannot write data into files when when there is tiny space in the filesystem.
> 
> Reproduce steps:
>  # mkfs.btrfs /dev/sda1
>  # mount /dev/sda1 /mnt
>  # dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
>  # dd if=/dev/zero of=/mnt/tmpfile1 bs=4K count=99999999999999
>    (fill the filesystem)
>  # umount /mnt
>  # mount /dev/sda1 /mnt
>  # rm -f /mnt/tmpfile0
>  # dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
>    (failed with nospec)
> 
> But if we do the last step again, we can write data successfully. The reason of
> the problem is that btrfs didn't try to commit the current transaction and
> reclaim some space when chunk allocation failed.
> 
> This patch fixes it by committing the current transaction to to reclaim some
> space when chunk allocation fails.
> 
> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>

Reviewed-by: Josef Bacik <josef@redhat.com>

Thanks,

Josef