[arch-projects] [RFC 18/23] Support the tmp= option for running mkfs on mapped device

[Matthew Monaco]

On 05/18/2012 05:15 PM, Tom Gundersen wrote:
> On Fri, May 18, 2012 at 6:22 PM, Matthew Monaco <dgbaley27 at 0x01b.net> wrote:
>> It seems like some people use this. Use a new variable "tmpfs" to
>> contain the file system type. Default to ext4 (Debian does this). Use
>> the same variable to track the swap option too because we can only do
>> one or the other.
> 
> For the record: I don't see the value of this, and think people should
> use a real tmpfs backed by encrypted swap.
> 
> That said, if there is demand for it I won't object. Does Debian
> support choosing your own filesystem or do they always use ext4?
> Having this be configurable seems a bit over the top to me...
> 

I implemented this exactly as debian does, "tmp" means ext4, but
"tmp=<anything>" works too. I have no use for it, and wasn't even planning to
add it, but I saw how simple it would be following the mkswap support (which I
and others definitely do use).

>> ---
>>  cryptmount.sh |   21 +++++++++++++++------
>>  1 file changed, 15 insertions(+), 6 deletions(-)
>>
>> diff --git a/cryptmount.sh b/cryptmount.sh
>> index 37f5121..5320e3d 100755
>> --- a/cryptmount.sh
>> +++ b/cryptmount.sh
>> @@ -155,7 +155,7 @@ ct_main() {
>>
>>        # Pre-parse OPTIONS, a little ugly, but it works
>>        preparse() {
>> -               local args swap
>> +               local args tmpfs
>>                if ! ct_parse_options $OPTIONS; then
>>                        error "Invalid options string: $OPTIONS"
>>                        exit 1
>> @@ -392,7 +392,7 @@ ct_unmap() {
>>
>>  ct_map() {
>>
>> -       local name="$1" dev="$2" key="$3" args="" swap=0
>> +       local name="$1" dev="$2" key="$3" args="" tmpfs
>>        local key_dev="" key_fstype="" key_mntpnt="" key_dev_umount=0
>>        shift 3
>>
>> @@ -401,7 +401,7 @@ ct_map() {
>>                return 1
>>        fi
>>
>> -       # this function sets the args and swap variables
>> +       # this function sets the args and tmpfs variables
>>        if ! ct_parse_options "$@"; then
>>                error "Unable to parse options"
>>                return 1
>> @@ -520,13 +520,20 @@ ct_map() {
>>                        ret=1
>>                elif run cryptsetup create $key $args "$name" "$dev"; then
>>                        info "sucessfully mapped '$dev' to '/dev/mapper/$name'"
>> -                       if [ $swap -eq 1 ]; then
>> +                       if [ "$tmpfs" = "swap" ]; then
>>                                if run mkswap -f -L "$name" "/dev/mapper/$name"; then
>>                                        info "mkswap successful on '/dev/mapper/$name'"
>>                                else
>>                                        error "mkswap failed for '/dev/mapper/$name'"
>>                                        ret=1
>>                                fi
>> +                       elif [ "$tmpfs" ]; then
>> +                               if run mkfs -t "$tmpfs" "/dev/mapper/$name"; then
>> +                                       info "mkfs successful on '/dev/mapper/$name'"
>> +                               else
>> +                                       error "mkfs failed for '/dev/mapper/$name'"
>> +                                       ret=1
>> +                               fi
>>                        fi
>>                else
>>                        error "unable to map '$dev' to '/dev/maper/name/$name'"
>> @@ -617,7 +624,7 @@ ct_parse_options() {
>>                case "$key" in
>>                        swap)
>>                                # set external variable
>> -                               swap=1
>> +                               tmpfs="swap"
>>                                ;;
>>                        luks|plain)
>>                                warn "Ignoring option $key, LUKS volumes are automatically detected"
>> @@ -629,7 +636,9 @@ ct_parse_options() {
>>                                warn "Ignoring Debian specific option '$key'"
>>                                ;;
>>                        tmp)
>> -                               warn "The tmp= option is not supported"
>> +                               # set an external variable
>> +                               [ -z "$val" ] && msg "Defaulting tmp to ext4"
>> +                               tmpfs="${val:-ext4}"
>>                                ;;
>>                        size)
>>                                args="$args --key-size $val"
>> --
>> 1.7.10.2
>>


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