split btrfs-shrink out of btarfs

3 files changed, 256 insertions, 0 deletions

diff --git a/src/btrfs-utils/btarfs b/src/btrfs-utils/btarfs
new file mode 100755
index 0000000..a51b2ef
--- /dev/null
+++ b/src/btrfs-utils/btarfs
@@ -0,0 +1,105 @@
+#!/bin/sh
+
+die() { printf "%s: Error: %s\n" "$0" "$*" >&2; exit 1; }
+
+[ "$(id -u)" = 0 ] || die 'you are not root'
+
+TEMP="$(getopt -o 'f:vcxz' --long size:,file:,create,extract,gzip,gunzip,ungzip -n "$0" -- "$@")" ||
+    die 'getopt error'
+eval set -- "$TEMP"
+
+MIN_BYTES=$((128 * 1024 * 1024))
+
+FILE=
+MODE=
+ZIP=y
+BYTES=$((256 * 1024 * 1024))
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --size)
+            BYTES=$(( $2 * 1024 * 1024))
+            [ "$BYTES" -ge "$MIN_BYTES" ] || die "invalid size (too small or not a number)"
+            SIZE="$2"
+            shift 2 ;;
+        -f|--file)
+            [ "$FILE" ] && die "only one archive file can be specified"
+            FILE="$2"
+            shift 2 ;;
+        -c|--create)
+            [ "$MODE" ] && die "incompatible modes"
+            MODE=create
+            shift ;;
+        -x|--extract)
+            [ "$MODE" ] && die "incompatible modes"
+            MODE=extract
+            shift ;;
+        -v)
+            VERBOSE=y
+            shift ;;
+        -z|--gzip|--gunzip|--ungzip)
+            ZIP=y
+            shift ;;
+        --)
+            shift; break;;
+        *) die 'getopt error';;
+    esac
+done
+[ "$FILE" ] || die "you must specify a file (this is not tar, there is no stdout)"
+
+create()
+{
+    TMPFILE=$(dirname "$FILE")/.~.$(basename "$FILE")
+#   [ ! -e "$FILE" ] || die "refusing to overwrite '$FILE'"
+#   [ ! -e "$TMPFILE" ] || die "refusing to overwrite '.~.$FILE'"
+    rm -f "$TMPFILE"
+    fallocate -l "$BYTES" "$TMPFILE"
+    mountpoint=$(mktemp -d) || die
+    trap 'umount "$mountpoint"; rmdir "$mountpoint"; rm "$TMPFILE"' EXIT
+    mkfs.btrfs "$TMPFILE" || die
+    mount -o ${ZIP:+compress,}loop "$TMPFILE" "$mountpoint" || die
+    rsync -a ${VERBOSE:+ -i} "$@" "$mountpoint" || die
+
+    shrink "$mountpoint"
+    umount "$mountpoint" || die
+    btrfs_truncate "$TMPFILE"
+
+    rmdir "$mountpoint"
+    btrfstune -S1 "$TMPFILE" || die
+    mv "$TMPFILE" "$FILE"
+    trap '' EXIT
+}
+
+btrfs_truncate()
+{
+    local img="$1" bytes
+    bytes=$(file "$img" | sed -ne 's?.*/\([0-9]*\) bytes used.*?\1?p')
+    if [ "$bytes" ]; then
+        truncate -s "$bytes" "$img"
+    fi
+}
+
+
+get_k()
+{
+    local mountpoint="$1" kilos
+    kilos=$(btrfs fi usage -k "$mountpoint"|sed -ne 's/[\t ]*Device size:[\t ]*//p')
+    case "$kilos" in
+        *.00KiB) echo "${kilos%.00KiB}";;
+        *) return 1;;
+    esac
+}
+
+shrink()
+{
+    shrinkmegs=100
+    while true; do
+        while ! btrfs filesystem resize -${shrinkmegs}M "$mountpoint"/; do
+            shrinkmegs=$((shrinkmegs - 10 ))
+            if [ $shrinkmegs -lt 10 ]; then
+                return
+            fi
+        done
+    done
+}
+
+$MODE "$@"
diff --git a/src/btrfs-utils/btrfs-shrink b/src/btrfs-utils/btrfs-shrink
new file mode 100755
index 0000000..f3dbbb0
--- /dev/null
+++ b/src/btrfs-utils/btrfs-shrink
@@ -0,0 +1,52 @@
+#!/bin/sh
+
+die() { printf "%s: Error: %s\n" "$0" "$*" >&2; exit 1; }
+
+[ "$(id -u)" = 0 ] || die 'you are not root'
+
+shrink()
+{
+    shrinkmegs=100
+    while true; do
+        while ! btrfs filesystem resize -${shrinkmegs}M "$mountpoint"/; do
+            shrinkmegs=$((shrinkmegs - 10 ))
+            if [ $shrinkmegs -lt 10 ]; then
+                return
+            fi
+        done
+    done
+}
+
+btrfs_truncate()
+{
+    local img="$1" bytes
+    bytes=$(file "$img" | sed -ne 's?.*/\([0-9]*\)/[0-9]* bytes used.*?\1?p')
+#   548044800/1176715264 bytes used
+    if [ "$bytes" ]; then
+        truncate -s "$bytes" "$img"
+    fi
+}
+
+main()
+{
+    if [ -d "$1" ]; then
+        mountpoint -q "$1" || die "not a mountpoint: $1"
+        shrink "$1"
+    elif [ -f "$1" ]; then
+        mkdir "$1".mnt.tmp
+        mount -t btrfs "$1" "$1".mnt.tmp
+        result=$?
+        if [ $result = 0 ]; then
+            shrink "$1".mnt.tmp
+            result=$?
+        fi
+        umount "$1".mnt.tmp
+        rmdir "$1".mnt.tmp
+        btrfs_truncate "$1"
+        return $result
+    else
+        die "not a file or directory: $1"
+    fi
+}
+
+main "$@"
diff --git a/src/btrfs-utils/with-btrfs-seed b/src/btrfs-utils/with-btrfs-seed
new file mode 100755
index 0000000..637af5a
--- /dev/null
+++ b/src/btrfs-utils/with-btrfs-seed
@@ -0,0 +1,99 @@
+#!/bin/sh
+
+usage()
+{
+    cat >&2 <<EOF
+usage: $0 [options] <file.iso> [command] [args ...]
+
+    options:
+        --resize <size>
+        --btrfs-options <mount options>     (default: compress)
+        --no-chroot
+EOF
+    exit $1
+}
+
+error()
+{
+    printf '%s: Error: %s\n' "$0" "$*" >&2
+    exit 1
+}
+
+warning()
+{
+    printf '%s: Warning: %s\n' "$0" "$*" >&2
+}
+
+have_root()
+{
+    [ "$(id -u)" = 0 ]
+}
+
+main()
+{
+    have_root || error "you are not root"
+
+    iso_file=$1
+    shift
+
+    iso_file_clone=${iso_file}.clone.tmp
+    mountpoint=${iso_file%.iso}.mnt.tmp
+
+    [ -f "$iso_file" ]                                        || error "not a file: $iso_file"
+    [ ! -f "$iso_file_clone" ]                                || error "refusing to clobber existing file: $iso_file_clone"
+    [ -d "$mountpoint" ] || mkdir "$mountpoint"               || error "could not create directory $mountpoint"
+    ! mountpoint -q "$mountpoint"                             || error "directory is already a mountpoint: $mountpoint"
+
+    cp --reflink=always "$iso_file" "$iso_file_clone"         || error "cp failed"
+    trap 'rm -f "$iso_file_clone"' EXIT
+
+    if [ "$RESIZE" ]; then
+        truncate --size="$RESIZE" "$iso_file_clone"           || error "failed to resize image with truncate"
+    fi
+
+    btrfstune -f -S 0 "$iso_file_clone" 2>/dev/null           || error "btrfstune failed"
+    mount_options=rw,loop${BTRFS_OPTIONS:+,$BTRFS_OPTIONS}
+    mount -o "$mount_options" "$iso_file_clone" "$mountpoint" || error "failed to mount $iso_file"
+
+    if [ "$RESIZE" ]; then
+        btrfs filesystem resize max "$mountpoint"             || error "btrfs filesystem resize"
+    fi
+
+    if [ "$CHROOT" ]; then
+        chroot "$mountpoint" "$@"
+    else
+        "$@" "$mountpoint"
+    fi
+    result=$?
+    umount "$mountpoint" || warning "umount $mountpoint failed!  You had better do something about it"
+    rmdir "$mountpoint"
+    if [ "$result" = 0 ]; then
+        btrfstune -S 1 "$iso_file_clone" || error "btrfstune failed.  The original ISO is unmodified."
+        mv "$iso_file_clone" "$iso_file"
+    else
+        warning "The command executed within the chroot failed.  The original ISO is unmodified."
+        rm "$iso_file_clone"
+    fi
+}
+
+[ $# = 0 ] && usage 0
+
+CHROOT=y
+eval set -- "$(getopt -o '' --long shrink,no-chroot,resize:,fork:,btrfs-options: -n "$0" -- "$@")" || error 'getopt error'
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --) shift; break;;
+        --resize) RESIZE=$2; shift 2;;
+        --fork) FORK=$2; shift 2;;
+        --btrfs-options) BTRFS_OPTIONS=$2; shift 2;;
+        --no-chroot) CHROOT=; shift;;
+        --shrink) SHRINK=y; shift;;
+        *) error "unrecognized option: $1"
+    esac
+done
+
+: ${BTRFS_OPTIONS:=compress}
+
+[ "$FORK" ] && error "unimplemented option: --fork"
+
+main "$@"