Re: [PATCH v6 2/3] common/zoned: add helpers for creation and teardown of zloop devices

["Darrick J. Wong" <djwong@kernel.org>]

On Fri, Oct 17, 2025 at 07:50:07AM +0200, Johannes Thumshirn wrote:
> Add _create_zloop, _destroy_zloop and _find_next_zloop helper functions
> for creating destroying and finding the next free zloop device.
> 
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>  common/zoned | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/common/zoned b/common/zoned
> index 41697b08..e2f5969c 100644
> --- a/common/zoned
> +++ b/common/zoned
> @@ -45,3 +45,56 @@ _require_zloop()
>  	    _notrun "This test requires zoned loopback device support"
>      fi
>  }
> +
> +_find_next_zloop()
> +{
> +    id=0

local id=0

(so the helper won't reassign a variable in the caller's scope)

With that fixed,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> +
> +    while true; do
> +        if [[ ! -b "/dev/zloop$id" ]]; then
> +            break
> +        fi
> +        id=$((id + 1))
> +    done
> +
> +    echo "$id"
> +}
> +
> +# Create a zloop device
> +# usage: _create_zloop <base_dir> <zone_size> <nr_conv_zones>
> +_create_zloop()
> +{
> +    local id="$(_find_next_zloop)"
> +
> +    if [ -n "$1" ]; then
> +        local zloop_base="$1"
> +    else
> +        local zloop_base="/var/local/zloop"
> +    fi
> +
> +    if [ -n "$2" ]; then
> +        local zone_size=",zone_size_mb=$2"
> +    fi
> +
> +    if [ -n "$3" ]; then
> +        local conv_zones=",conv_zones=$3"
> +    fi
> +
> +    mkdir -p "$zloop_base/$id"
> +
> +    local zloop_args="add id=$id,base_dir=$zloop_base$zone_size$conv_zones"
> +
> +    echo "$zloop_args" > /dev/zloop-control || \
> +        _fail "cannot create zloop device"
> +
> +    echo "/dev/zloop$id"
> +}
> +
> +_destroy_zloop() {
> +    local zloop="$1"
> +
> +    test -b "$zloop" || return
> +    local id=$(echo $zloop | grep -oE '[0-9]+$')
> +
> +    echo "remove id=$id" > /dev/zloop-control
> +}
> -- 
> 2.51.0
> 
>