SWAMPy

✎ CARVE FLESH

EDITING: bcache-export-cached

#!/bin/sh
#
# This program reads the bcache superblock on bcacheX slaves to extract the
# dev.uuid and dev.label which refer to a specific backing device.
#
# It integrates with udev 'import' by writing CACHED_UUID=X and optionally
# CACHED_LABEL=X for the backing device of the provided bcache device.
# Ignore caching devices by skipping unless sb.version=1
#
# There is 1 and only 1 backing device (slaves/*) for a bcache device.

TEMPNODE=${1}               # /dev/bcacheN
DEVNAME=${TEMPNODE##*/}     # /dev/bcacheN -> bcacheN

for slave in "/sys/class/block/$DEVNAME/slaves"/*; do
    [ -d "$slave" ] || continue
    /usr/sbin/bcache-super-show "/dev/${slave##*/}" |
       awk '$1 == "sb.version" { sbver=$2; }
            $1 == "dev.uuid" { uuid=$2; }
            $1 == "dev.label" && $2 != "(empty)" { label=$2; }
            END {
                if (sbver == 1 && uuid) {
                    print("CACHED_UUID=" uuid)
                    if (label) print("CACHED_LABEL=" label)
                    exit(0)
                }
                exit(1);
            }'
    # awk exits 0 if it found a backing device.
    [ $? -eq 0 ] && exit 0
done

CANCEL

Name	Type	Size	Modified	Actions
↩ ..	DIR	—	—
📁 hwdb.d/	DIR	—	2026-06-09 06:53
📁 rules.d/	DIR	—	2026-07-18 06:43
📄 ata_id	?	82.7 KB	2026-06-05 15:36	EDIT
📄 bcache-export-cached	?	1.1 KB	2024-04-08 15:54	EDIT
📄 bcache-register	?	14.3 KB	2024-04-08 15:54	EDIT
📄 cdrom_id	?	90.7 KB	2026-06-05 15:36	EDIT
📄 dmi_memory_id	?	86.7 KB	2026-06-05 15:36	EDIT
📄 fido_id	?	138.7 KB	2026-06-05 15:36	EDIT
📄 hdparm	?	1.4 KB	2022-10-06 12:47	EDIT
📄 hwdb.bin	BIN	11.7 MB	2026-06-09 06:53	EDIT
📄 iocost	?	150.9 KB	2026-06-05 15:36	EDIT
📄 kpartx_id	?	2.3 KB	2025-07-22 15:44	EDIT
📄 mtd_probe	?	34.6 KB	2026-06-05 15:36	EDIT
📄 probe-bcache	?	14.3 KB	2024-04-08 15:54	EDIT
📄 scsi_id	?	87.2 KB	2026-06-05 15:36	EDIT
📄 snappy-app-dev	?	22.2 KB	2026-07-13 14:38	EDIT
📄 usb_modeswitch	?	1.5 KB	2024-04-08 16:21	EDIT
📄 v4l_id	?	38.6 KB	2026-06-05 15:36	EDIT