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Merge pull request #51207 from samueldr/fix/sd-image-slimming 

sd-image: Slims the ext4 filesystem even more.
This commit is contained in:
Samuel Dionne-Riel 2018-12-06 23:35:09 +00:00 committed by GitHub
parent 3776a9e93d 61bdaad9a9
commit 70488665fa
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1 changed files with 19 additions and 0 deletions
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19
nixos/lib/make-ext4-fs.nix
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@ -94,5 +94,24 @@ pkgs.stdenv.mkDerivation {
cat errorlog cat errorlog
return 1 return 1
fi fi
(
# Resizes **snugly** to its actual limits (or closer to)
free=$(dumpe2fs $out | grep '^Free blocks:')
blocksize=$(dumpe2fs $out | grep '^Block size:')
blocks=$(dumpe2fs $out | grep '^Block count:')
blocks=$((''${blocks##*:})) # format the number.
blocksize=$((''${blocksize##*:})) # format the number.
# System can't boot with 0 blocks free.
# Add 16MiB of free space
fudge=$(( 16 * 1024 * 1024 / blocksize ))
size=$(( blocks - ''${free##*:} + fudge ))
echo "Resizing from $blocks blocks to $size blocks. (~ $((size*blocksize/1024/1024))MiB)"
EXT2FS_NO_MTAB_OK=yes resize2fs $out -f $size
)
# And a final fsck, because of the previous truncating.
fsck.ext4 -n -f $out
''; '';
} }