#!/bin/sh
# Test cp reads unwritten extents efficiently

# Copyright (C) 2011 Free Software Foundation, Inc.

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

. "${srcdir=.}/init.sh"; path_prepend_ ../src
print_ver_ cp

touch fiemap_chk
fiemap_capable_ fiemap_chk ||
  skip_test_ 'this file system lacks FIEMAP support'
rm fiemap_chk

# TODO: rather than requiring `fallocate`, possible add
# this functionality to truncate --alloc
fallocate --help >/dev/null || skip_test_ 'The fallocate utility is required'
fallocate -l 1 -n falloc.test ||
  skip_test_ 'this file system lacks FALLOCATE support'
rm falloc.test

fallocate -l 600000000 space.test ||
  skip_test_ 'this test needs at least 600MB free space'

# Disable this test on old BTRFS (e.g. Fedora 14)
# which reports ordinary extents for unwritten ones.
filefrag space.test || skip_test_ 'the `filefrag` utility is missing'
filefrag -v space.test | grep -F 'unwritten' > /dev/null ||
  skip_test_ 'this file system does not report empty extents as "unwritten"'

rm space.test

# Ensure we read a large empty file quickly
fallocate -l 300000000 empty.big || framework_failure
timeout 3 cp --sparse=always empty.big cp.test || fail=1
test $(stat -c %s empty.big) = $(stat -c %s cp.test) || fail=1
rm empty.big cp.test

# Ensure we handle extents beyond file size correctly.
# Note until we support fallocate, we will not maintain
# the file allocation.  FIXME: amend this test when fallocate is supported.
fallocate -l 10000000 -n unwritten.withdata || framework_failure
dd count=10 if=/dev/urandom conv=notrunc iflag=fullblock of=unwritten.withdata
cp unwritten.withdata cp.test || fail=1
test $(stat -c %s unwritten.withdata) = $(stat -c %s cp.test) || fail=1
cmp unwritten.withdata cp.test || fail=1
rm unwritten.withdata cp.test

# The following to generate unaccounted extents followed by a hole, is not
# supported by ext4 at least. The ftruncate discards all extents not
# accounted for in the size.
#  fallocate -l 10000000 -n unacc.withholes
#  dd count=10 if=/dev/urandom conv=notrunc iflag=fullblock of=unacc.withholes
#  truncate -s20000000 unacc.withholes

# Ensure we handle a hole after empty extents correctly.
# Since all extents are accounted for in the size,
# we can maintain the allocation independently from
# fallocate() support.
fallocate -l 10000000 empty.withholes
truncate -s 20000000 empty.withholes
sectors_per_block=$(expr $(stat -c %o .) / 512)
cp empty.withholes cp.test || fail=1
test $(stat -c %s empty.withholes) = $(stat -c %s cp.test) || fail=1
# These are usually equal but can vary by an IO block due to alignment
alloc_diff=$(expr $(stat -c %b empty.withholes) - $(stat -c %b cp.test))
alloc_diff=$(echo $alloc_diff | tr -d -- -) # abs()
test $alloc_diff -le $sectors_per_block || fail=1
# Again with SPARSE_ALWAYS
cp --sparse=always empty.withholes cp.test || fail=1
test $(stat -c %s empty.withholes) = $(stat -c %s cp.test) || fail=1
# cp.test should take 0 space, but allowing for some systems
# that store default extended attributes in data blocks
test $(stat -c %b cp.test) -le $sectors_per_block || fail=1
rm empty.withholes cp.test

Exit $fail