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.
Cheers, David
