152 lines
3.7 KiB
Bash
152 lines
3.7 KiB
Bash
#!/bin/bash
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#
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# This plugin defragments rpm files after update.
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#
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# If the filesystem is btrfs, run defrag command in /var/lib/rpm, set the
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# desired extent size to 32MiB, but this may change in the result depending
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# on the fragmentation of the free space
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#
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## Why 32MiB:
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# - the worst fragmentation has been observed on /var/lib/rpm/Packages
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# - this can grow up to several hundred of megabytes
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# - the file gets updated at random places
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# - although the file will be composed of many extents, it's faster to
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# merge only the extents that affect some portions of the file, instead
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# of the whole file; the difference is negligible
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# - due to the free space fragmentation over time, it's hard to find
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# contiguous space, the bigger the extent is, the worse and the extent
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# size hint is not reached anyway
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DEBUG="false"
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EXTENT_SIZE="32M"
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RPMDIR=$(rpm --eval "%_dbpath")
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SCRIPTNAME="$(basename "$0")"
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cleanup() {
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test -n "$tmpdir" -a -d "$tmpdir" && execute rm -rf "$tmpdir"
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}
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trap cleanup EXIT
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tmpdir=$(mktemp -d /tmp/btrfs-defrag-plugin.XXXXXX)
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log() {
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logger -p info -t $SCRIPTNAME --id=$$ "$@"
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}
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debug() {
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$DEBUG && log "$@"
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}
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respond() {
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debug "<< [$1]"
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echo -ne "$1\n\n\x00"
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}
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execute() {
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debug -- "Executing: $@"
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$@ 2> $tmpdir/cmd-output
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ret=$?
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if $DEBUG; then
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if test $ret -ne 0; then
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log -- "Command failed, output follows:"
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log -f $tmpdir/cmd-output
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log -- "End output"
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else
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log -- "Command succeeded"
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fi
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fi
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return $ret
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}
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btrfs_defrag() {
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# defrag options:
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# - verbose
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# - recursive
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# - flush each file before going to the next one
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# - set the extent target hint
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execute btrfs filesystem defragment -v -f -r -t "$EXTENT_SIZE" "$RPMDIR"
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}
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debug_fragmentation() {
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if $DEBUG; then
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log -- "Fragmentation $1"
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execute filefrag $RPMDIR/* > $tmpdir/filefrag-output
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if test $? -eq 0; then
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log -f $tmpdir/filefrag-output
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log -- "End output"
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else
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log "Non-fatal error ignored."
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fi
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fi
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}
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ret=0
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# The frames are terminated with NUL. Use that as the delimeter and get
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# the whole frame in one go.
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while read -d ' ' -r FRAME; do
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echo ">>" $FRAME | debug
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# We only want the command, which is the first word
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read COMMAND <<<$FRAME
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# libzypp will only close the plugin on errors, which may also be logged.
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# It will also log if the plugin exits unexpectedly. We don't want
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# to create a noisy log when using another file system, so we just
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# wait until COMMITEND to do anything. We also need to ACK _DISCONNECT
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# or libzypp will kill the script, which means we can't clean up.
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debug "COMMAND=[$COMMAND]"
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case "$COMMAND" in
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COMMITEND) ;;
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_DISCONNECT)
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respond "ACK"
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break
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;;
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*)
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respond "_ENOMETHOD"
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continue
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;;
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esac
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# We don't have anything to do if it's not btrfs.
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FSTYPE=$(execute stat -f --format=%T $RPMDIR)
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if test $? -ne 0; then
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respond "ERROR"
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ret=1
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break
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fi
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debug "Output follows:"
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debug "$FSTYPE"
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debug -- "End output"
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if test "$FSTYPE" != "btrfs"; then
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debug "Nothing to do: RPM Database is on $FSTYPE file system."
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respond "_ENOMETHOD"
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continue
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fi
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debug_fragmentation "before defrag run"
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btrfs_defrag > $tmpdir/defrag-output
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if test $? -ne 0; then
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respond "ERROR"
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ret=1
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break
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fi
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# Log the output if we're in debug mode
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debug "Output follows:"
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debug -f $tmpdir/defrag-output
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debug -- "End output"
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debug_fragmentation "after defrag run"
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respond "ACK"
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done
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debug "Terminating with exit code $ret"
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exit $ret
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