mirror of
https://codeberg.org/wonky/udev-usb-sync.git
synced 2024-09-19 15:30:35 +02:00
70 lines
No EOL
2.3 KiB
Bash
Executable file
70 lines
No EOL
2.3 KiB
Bash
Executable file
#!/usr/bin/bash
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#
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# The script is part of udev-usb-sync package
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the Affero GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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# @linux-aarhus - root.nix.dk
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#
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# configuration : /etc/usb-dev-sync/usb-dev-sync.conf
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# triggered by : /etc/udev/rules.d/99-usb-sync.rules
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#
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# contributors: @megavolt (Manjaro Forum)
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# : @linux-aarhus (Manjaro Forum)
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# inspired by : @kwg (EndeavourOS Forum)
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#
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# Arguments provided by udev rule
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# $1: usb block device
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# $2: usb bandwidth reported by device
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#
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set -euo pipefail
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LANG=C
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LC_NUMERIC=C
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AUTOCALC=${AUTOCALC:-1}
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CONFIG='/etc/udev-usb-sync/udev-usb-sync.conf'
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[[ -f $CONFIG ]] && source $CONFIG
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BLOCKDEVICE="$1"
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SPEED="$2"
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# disable write cache for device if possible
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[[ -n $(which hdparm) ]] && $(which hdparm) -W 0 /dev/$BLOCKDEVICE > /dev/null
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# the following rules is introduced with kernel 6.2
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# https://docs.kernel.org/admin-guide/abi-testing.html#abi-sys-class-bdi-bdi-max-bytes
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case $AUTOCALC in
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0) # apply 16M as max_bytes
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echo 16777216 > /sys/block/$BLOCKDEVICE/bdi/max_bytes
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;;
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1) BUFFER_TIME=${BUFFER_TIME:-"0.05"}
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SAFETY_FACTOR=${SAFETY_FACTOR:-"1.3"}
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BUFFER_SIZE=$(printf '%.0f' `echo "( ($SPEED / 8) * $BUFFER_TIME * $SAFETY_FACTOR) * 1024 * 1024" | bc`)
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# for x in 12 480 5000 10000; do echo -n "$x -> " ;printf "%.0f\n" ` echo "(($x / 8) * 0.05 * 1.3) * 1024 * 1024" | bc`; done
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# 62915
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# 4089446
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# 42593157
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# 85196800
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# apply calculated buffer size
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echo "$BUFFER_SIZE" > /sys/block/$BLOCKDEVICE/bdi/max_bytes
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;;
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esac
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# https://docs.kernel.org/admin-guide/abi-testing.html#abi-sys-class-bdi-bdi-strict-limit
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# apply strict limit
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echo 1 > /sys/block/$BLOCKDEVICE/bdi/strict_limit |