54 lines
990 B
Plaintext
54 lines
990 B
Plaintext
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#!/bin/sh
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#
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# BTRFS delta snapshots with incomplete send handling
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# CC0 ~caskd
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: ${SRC:?'Source not defined'}
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: ${SNAPDIR:?'Snapdir not defined'}
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: ${DEST:?'Destination not defined'}
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CDATE="$(date '+%s')"
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SNAPSRC="$SRC"
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SNAPPATH="$SNAPSRC/$SNAPDIR"
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PREV="$SRC/prev"
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CUR="$SRC/cur"
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TMP="$SRC/tmp"
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SNAPDEST="$SNAPPATH/$CDATE"
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msg() {
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echo "$1" >&2
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}
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delta() {
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[ -d "$(realpath "$CUR")" ] || return 1
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msg "Attempting to send delta"
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btrfs -v send --compressed-data -p "$CUR" "$TMP" | btrfs -v receive "$DEST"
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}
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full() {
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msg "Attempting to send full"
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btrfs -v send --compressed-data "$TMP" | btrfs -v receive "$DEST"
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}
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symdel() {
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if [ -L "$1" ]; then
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btrfs subvolume delete "$1" >&2 || true
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rm -v "$1" >&2
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fi
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}
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mkdir -vp "$SNAPPATH" >&2
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symdel "$TMP"
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symdel "$PREV"
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ln -sv "$CDATE" "$TMP" >&2
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btrfs subvolume snapshot -r "$SNAPSRC" "$SNAPDEST" >&2
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delta || full
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# Mark snapshot transmission as complete
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[ -L "$CUR" ] && \
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mv -v "$CUR" "$PREV" >&2
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mv -v "$TMP" "$CUR" >&2
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