David Disseldorp <ddiss@xxxxxxx> writes:
> On Thu, 09 Jun 2022 15:54:15 +0100, Luís Henriques wrote:
>
>> David Disseldorp <ddiss@xxxxxxx> writes:
> ...
>> > I take it a more exact calculation would be something like:
>> > (64K - $max_attrval_namelen - sizeof(user.snrub="fish2\012"))?
>> >
>> > Perhaps you could calculate this on the fly for CephFS by passing in the
>> > filename and subtracting the `getfattr -d $filename` results... That
>> > said, it'd probably get a bit ugly, expecially if encoding needs to be
>> > taken into account.
>>
>> In fact, this is *exactly* what I had before Dave suggested to keep it
>> simple.
>
> Arg, sorry I missed your previous round.
>
>> After moving the code back into common/attr, where's how the
>> generic code would look like:
>>
>> + ceph)
>> + # CephFS does have a limit for the whole set of names+values
>> + # attributes in a file. Thus, it is necessary to get the sizes
>> + # of all names and values already existent and subtract them to
>> + # the (default) maximum, which is 64k.
>> + local len=0
>> + while read line; do
>> + # skip 1st line
>> + [ "$line" != "${line#'#'}" ] && continue
>> + n=$(echo $line | awk -F"=0x" '{print $1}')
>> + v=$(echo $line | awk -F"=0x" '{print $2}')
>> + nlen=${#n}
>> + vlen=${#v}
>> + # total is the sum of the name len and the value len
>> + # divided by 2 because we're dumping them in hex format
>> + t=$(($nlen + $vlen / 2))
>> + len=$(($len + $t))
>> + done <<< $(_getfattr -d -e hex $file 2> /dev/null)
>> + echo $((65536 - $max_attrval_namelen - $len))
>> + ;;
>>
>> so... yeah, I'm not particularly gifted on shell, it could probably be
>> done in more clever/cleaner ways. Anyway, I'm open to revisit this if
>> this is the preferred solution.
>
> hmm, I was hoping something like...
> (( 65536 - $max_attrval_namelen - $(getfattr -d $file | _filter | wc -c) ))
> would be possible, but getfattr output does make it a bit too messy.
Yeah, also we must decode the attributes as hex otherwise we'll miss
non-string values. Anyway, I'll see if I find something better. Thanks,
David.
Cheers,
--
Luis
