Re: [PATCH v3] generic: make 17[1-4] work well when btrfs compression is enabled

[Eryu Guan <eguan@redhat.com>]

On Wed, Oct 26, 2016 at 05:52:11PM +0800, Wang Xiaoguang wrote:
> When enabling btrfs compression, original codes can not fill fs
> correctly, here we introduce _fill_fs() in common/rc, which'll keep
> creating and writing files until enospc error occurs. Note _fill_fs
> is copied from tests/generic/256, but with some minor modifications.
> 
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>

Looks fine to me overall, generic/17[1-4] and generic/256 passed on xfs,
btrfs and btrfs with compress. But I'd like Darrick to review it as well :)

> ---
> V2: In common/, I did't find an existing function suitable for
>     these 4 test cases to fill fs, so I still use _pwrite_byte() with
>     a big enough file length fo fill fs. Note, for btrfs, metadata space
>     still is not full, only data space is full, but it's OK for these
>     4 test cases.
> 
>     All these 4 cases pass in xfs and btrfs(without compression), if
>     btrfs has compression enabled, these 4 cases will fail for false
>     enospc error, I have sent kernel patches to fix this bug.
> 
> V3: Introduce  _fill_fs in common/rc to fill fs.
> ---
>  common/rc         | 50 ++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/171 |  4 +---
>  tests/generic/172 |  4 ++--
>  tests/generic/173 |  4 +---
>  tests/generic/174 |  4 +---
>  tests/generic/256 | 65 +++++--------------------------------------------------
>  6 files changed, 60 insertions(+), 71 deletions(-)
> 
> diff --git a/common/rc b/common/rc
> index 7a9fc90..0e1ac5d 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -4003,6 +4003,56 @@ _require_xfs_mkfs_without_validation()
>  	fi
>  }
>  
> +# Fill a file system by repeatedly creating files in the given folder
> +# starting with the given file size.  Files are reduced in size when
> +# they can no longer fit until no more files can be created.
> +_fill_fs()
> +{
> +	local file_size=$1
> +	local dir=$2
> +	local block_size=$3
> +	local switch_user=$4
> +	local file_count=1
> +	local bytes_written=0
> +
> +	if [ $# -ne 4 ]; then
> +		echo "Usage: _fill_fs filesize dir blocksize"

The usage info here is wrong, missing the "switch user" argument.

Thanks,
Eryu