kumquat-buildroot/fs/ext2/genext2fs.sh
Peter Korsgaard eeea3ea6a8 genext2fs.sh: improve number of blocks calculation
Closes #2929

Instead of just adding a fixed amount to the blocks used, try to
estimate the real space needed according to the filesystem structure
(bitmaps, inodes, blocks).

The side effect of this is that we no longer significantly overestimate
the size needed for small file systems.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
2010-12-30 23:10:21 +01:00

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#!/bin/sh
# genext2fs wrapper calculating needed blocks/inodes values if not specified
export LC_ALL=C
CALC_BLOCKS=1
CALC_INODES=1
while getopts x:d:D:b:i:N:m:g:e:zfqUPhVv f
do
case $f in
b) CALC_BLOCKS=0 ;;
N) CALC_INODES=0; INODES=$OPTARG ;;
d) TARGET_DIR=$OPTARG ;;
esac
done
# calculate needed inodes
if [ $CALC_INODES -eq 1 ];
then
INODES=$(find $TARGET_DIR | wc -l)
INODES=$(expr $INODES + 400)
set -- $@ -N $INODES
fi
# calculate needed blocks
if [ $CALC_BLOCKS -eq 1 ];
then
# size ~= superblock, block+inode bitmaps, inodes (8 per block), blocks
# we scale inodes / blocks with 10% to compensate for bitmaps size + slack
BLOCKS=$(du -s -c -k $TARGET_DIR | grep total | sed -e "s/total//")
BLOCKS=$(expr 500 + \( $BLOCKS + $INODES / 8 \) \* 11 / 10)
set -- $@ -b $BLOCKS
fi
exec genext2fs $@