From 759b0ac9e7f3fbd0f04090e3142087bf692e47bc Mon Sep 17 00:00:00 2001 From: Pádraig Brady
Date: Thu, 2 Oct 2014 14:07:42 +0100 Subject: copy: detect smaller holes than the copy buffer size Previously cp would not detect runs of NULs that were smaller than the buffer size used for I/O (currently 128KiB). * src/copy.c (copy_reg): Use an independent hole_size, set to st_blksize, to increase the chances of detecting a representable hole, in a run of NULs read from the input. (create_hole): A new function refactored from sparse_copy() and extent_copy() so we have a single place to handle holes. (sparse_copy): Adjust to loop over the larger input buffer in chunks of the passed hole size. Also adjust to only call lseek once per hole, rather than at least once per input buffer. * tests/cp/sparse.sh: Add test cases for various sparse chunk sizes. * NEWS: Mention the improvement. --- tests/cp/sparse.sh | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'tests/cp/sparse.sh') diff --git a/tests/cp/sparse.sh b/tests/cp/sparse.sh index d6cc4c4b1..3e4a67caf 100755 --- a/tests/cp/sparse.sh +++ b/tests/cp/sparse.sh @@ -37,4 +37,37 @@ test $(stat --printf %b copy) -le $(stat --printf %b sparse) || fail=1 cp --sparse=always --reflink sparse copy && fail=1 cp --sparse=never --reflink sparse copy && fail=1 + +# Ensure we handle sparse/non-sparse transitions correctly +maxn=128 # how many $hole_size chunks per file +hole_size=$(stat -c %o copy) +dd if=/dev/zero bs=$hole_size count=$maxn of=zeros || framework_failure_ +tr '\0' 'U' < zeros > nonzero || framework_failure_ + +for pattern in 1 0; do + test "$pattern" = 1 && pattern="$(printf '%s\n%s' nonzero zeros)" + test "$pattern" = 0 && pattern="$(printf '%s\n%s' zeros nonzero)" + + for n in 1 2 4 11 32 $maxn; do + parts=$(expr $maxn / $n) + + rm -f sparse.in + + # Generate non sparse file for copying with alternating + # hole/data patterns of size n * $hole_size + for i in $(yes "$pattern" | head -n$parts); do + dd iflag=fullblock if=$i of=sparse.in conv=notrunc oflag=append \ + bs=$hole_size count=$n status=none || framework_failure_ + done + + cp --sparse=always sparse.in sparse.out || fail=1 # non sparse input + cp --sparse=always sparse.out sparse.out2 || fail=1 # sparse input + + cmp sparse.in sparse.out || fail=1 + cmp sparse.in sparse.out2 || fail=1 + + ls -lsh sparse.* + done +done + Exit $fail -- cgit v1.2.3-70-g09d2