32 lines
1.1 KiB
Bash
Executable File
32 lines
1.1 KiB
Bash
Executable File
#!/bin/sh
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#
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# This program reads the bcache superblock on bcacheX slaves to extract the
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# dev.uuid and dev.label which refer to a specific backing device.
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#
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# It integrates with udev 'import' by writing CACHED_UUID=X and optionally
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# CACHED_LABEL=X for the backing device of the provided bcache device.
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# Ignore caching devices by skipping unless sb.version=1
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#
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# There is 1 and only 1 backing device (slaves/*) for a bcache device.
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TEMPNODE=${1} # /dev/bcacheN
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DEVNAME=${TEMPNODE##*/} # /dev/bcacheN -> bcacheN
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for slave in "/sys/class/block/$DEVNAME/slaves"/*; do
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[ -d "$slave" ] || continue
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/usr/sbin/bcache-super-show "/dev/${slave##*/}" |
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awk '$1 == "sb.version" { sbver=$2; }
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$1 == "dev.uuid" { uuid=$2; }
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$1 == "dev.label" && $2 != "(empty)" { label=$2; }
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END {
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if (sbver == 1 && uuid) {
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print("CACHED_UUID=" uuid)
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if (label) print("CACHED_LABEL=" label)
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exit(0)
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}
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exit(1);
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}'
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# awk exits 0 if it found a backing device.
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[ $? -eq 0 ] && exit 0
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done
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