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#!/usr/bin/env bash
# nbdkit
# Copyright Red Hat
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# * Neither the name of Red Hat nor the names of its contributors may be
# used to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
source ./functions.sh
set -e
set -x
set -u
requires_run
requires_plugin sh
requires_nbdsh_uri
requires dd iflag=count_bytes </dev/null
files="readahead.out"
rm -f $files
cleanup_fn rm -f $files
define plugin <<'EOF'
case "$1" in
block_size)
echo 512 512 512
;;
thread_model)
echo parallel
;;
can_cache)
echo native
;;
get_size)
echo 1M
;;
cache)
echo "$@" >> readahead.out
;;
pread)
echo "$@" >> readahead.out
dd if=/dev/zero count=$3 iflag=count_bytes
;;
*)
exit 2
;;
esac
EOF
define script <<'EOF'
import time
for i in range(0, 512*10, 512):
h.pread(512, i)
# Give some time for bgthread to finish.
time.sleep(5)
EOF
export script
nbdkit -fv sh - <<<"$plugin" \
--filter=readahead \
--run 'nbdsh --uri "$uri" -c "$script"'
cat readahead.out
# We should see the pread requests, and additional cache requests for
# the 32K region following each pread request.
for i in `seq 0 512 $((512*10 - 512))` ; do
grep "pread 512 $i" readahead.out
grep "cache 32768 $((i+512))" readahead.out
done
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