Re: [PATCH v2] qcow2: Fix preallocation on images with unaligned sizes
On 17.06.20 16:00, Alberto Garcia wrote: > When resizing an image with qcow2_co_truncate() using the falloc or > full preallocation modes the code assumes that both the old and new > sizes are cluster-aligned. > > There are two problems with this: > > 1) The calculation of how many clusters are involved does not always > get the right result. > > Example: creating a 60KB image and resizing it (with > preallocation=full) to 80KB won't allocate the second cluster. > > 2) No copy-on-write is performed, so in the previous example if > there is a backing file then the first 60KB of the first cluster > won't be filled with data from the backing file. > > This patch fixes both issues. > > Signed-off-by: Alberto Garcia > --- > v2: iotests: don't check the image size if data_file is set [Max] > > block/qcow2.c | 17 ++--- > tests/qemu-iotests/125 | 24 > tests/qemu-iotests/125.out | 9 + > 3 files changed, 47 insertions(+), 3 deletions(-) Thanks, applied to my block branch: https://git.xanclic.moe/XanClic/qemu/commits/branch/block signature.asc Description: OpenPGP digital signature
Re: [PATCH v2] qcow2: Fix preallocation on images with unaligned sizes
ping On Wed 17 Jun 2020 04:00:36 PM CEST, Alberto Garcia wrote: > When resizing an image with qcow2_co_truncate() using the falloc or > full preallocation modes the code assumes that both the old and new > sizes are cluster-aligned. > > There are two problems with this: > > 1) The calculation of how many clusters are involved does not always > get the right result. > > Example: creating a 60KB image and resizing it (with > preallocation=full) to 80KB won't allocate the second cluster. > > 2) No copy-on-write is performed, so in the previous example if > there is a backing file then the first 60KB of the first cluster > won't be filled with data from the backing file. > > This patch fixes both issues. > > Signed-off-by: Alberto Garcia
Re: [PATCH v2] qcow2: Fix preallocation on images with unaligned sizes
On 6/17/20 9:00 AM, Alberto Garcia wrote: When resizing an image with qcow2_co_truncate() using the falloc or full preallocation modes the code assumes that both the old and new sizes are cluster-aligned. There are two problems with this: 1) The calculation of how many clusters are involved does not always get the right result. Example: creating a 60KB image and resizing it (with preallocation=full) to 80KB won't allocate the second cluster. 2) No copy-on-write is performed, so in the previous example if there is a backing file then the first 60KB of the first cluster won't be filled with data from the backing file. This patch fixes both issues. Signed-off-by: Alberto Garcia --- v2: iotests: don't check the image size if data_file is set [Max] Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
Re: [PATCH v2] qcow2: Fix preallocation on images with unaligned sizes
Patchew URL: https://patchew.org/QEMU/20200617140036.20311-1-be...@igalia.com/ Hi, This series failed the asan build test. Please find the testing commands and their output below. If you have Docker installed, you can probably reproduce it locally. === TEST SCRIPT BEGIN === #!/bin/bash export ARCH=x86_64 make docker-image-fedora V=1 NETWORK=1 time make docker-test-debug@fedora TARGET_LIST=x86_64-softmmu J=14 NETWORK=1 === TEST SCRIPT END === GEN docs/interop/qemu-qmp-ref.txt GEN docs/interop/qemu-qmp-ref.7 CC qga/commands.o /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) CC qga/guest-agent-command-state.o CC qga/main.o CC qga/commands-posix.o --- GEN docs/interop/qemu-ga-ref.html GEN docs/interop/qemu-ga-ref.txt GEN docs/interop/qemu-ga-ref.7 /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) AS pc-bios/optionrom/multiboot.o AS pc-bios/optionrom/linuxboot.o CC pc-bios/optionrom/linuxboot_dma.o --- SIGNpc-bios/optionrom/kvmvapic.bin SIGNpc-bios/optionrom/multiboot.bin SIGNpc-bios/optionrom/linuxboot.bin /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKivshmem-server /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKqemu-nbd BUILD pc-bios/optionrom/linuxboot_dma.img BUILD pc-bios/optionrom/pvh.img --- BUILD pc-bios/optionrom/pvh.raw SIGNpc-bios/optionrom/linuxboot_dma.bin SIGNpc-bios/optionrom/pvh.bin /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKqemu-storage-daemon /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKqemu-img /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKqemu-io LINKqemu-edid /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKfsdev/virtfs-proxy-helper LINKscsi/qemu-pr-helper /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKqemu-bridge-helper /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKvirtiofsd /usr/bin/ld: /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors_vfork.S.o): warning: common of `__interception::real_vfork' overridden by definition from /usr/lib64/clang/10.0.0/lib/linux/libclang_rt.asan-x86_64.a(asan_interceptors.cpp.o) LINKvhost-user-input
[PATCH v2] qcow2: Fix preallocation on images with unaligned sizes
When resizing an image with qcow2_co_truncate() using the falloc or
full preallocation modes the code assumes that both the old and new
sizes are cluster-aligned.
There are two problems with this:
1) The calculation of how many clusters are involved does not always
get the right result.
Example: creating a 60KB image and resizing it (with
preallocation=full) to 80KB won't allocate the second cluster.
2) No copy-on-write is performed, so in the previous example if
there is a backing file then the first 60KB of the first cluster
won't be filled with data from the backing file.
This patch fixes both issues.
Signed-off-by: Alberto Garcia
---
v2: iotests: don't check the image size if data_file is set [Max]
block/qcow2.c | 17 ++---
tests/qemu-iotests/125 | 24
tests/qemu-iotests/125.out | 9 +
3 files changed, 47 insertions(+), 3 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 0cd2e6757e..e20590c3b7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4239,8 +4239,8 @@ static int coroutine_fn
qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
old_file_size = ROUND_UP(old_file_size, s->cluster_size);
}
-nb_new_data_clusters = DIV_ROUND_UP(offset - old_length,
-s->cluster_size);
+nb_new_data_clusters = (ROUND_UP(offset, s->cluster_size) -
+start_of_cluster(s, old_length)) >> s->cluster_bits;
/* This is an overestimation; we will not actually allocate space for
* these in the file but just make sure the new refcount structures are
@@ -4317,10 +4317,21 @@ static int coroutine_fn
qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
int64_t nb_clusters = MIN(
nb_new_data_clusters,
s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset));
-QCowL2Meta allocation = {
+unsigned cow_start_length = offset_into_cluster(s, guest_offset);
+QCowL2Meta allocation;
+guest_offset = start_of_cluster(s, guest_offset);
+allocation = (QCowL2Meta) {
.offset = guest_offset,
.alloc_offset = host_offset,
.nb_clusters = nb_clusters,
+.cow_start= {
+.offset = 0,
+.nb_bytes = cow_start_length,
+},
+.cow_end = {
+.offset = nb_clusters << s->cluster_bits,
+.nb_bytes = 0,
+},
};
qemu_co_queue_init(_requests);
diff --git a/tests/qemu-iotests/125 b/tests/qemu-iotests/125
index d510984045..7cb1c19730 100755
--- a/tests/qemu-iotests/125
+++ b/tests/qemu-iotests/125
@@ -164,6 +164,30 @@ for GROWTH_SIZE in 16 48 80; do
done
done
+# Test image resizing using preallocation and unaligned offsets
+$QEMU_IMG create -f raw "$TEST_IMG.base" 128k | _filter_img_create
+$QEMU_IO -c 'write -q -P 1 0 128k' -f raw "$TEST_IMG.base"
+for orig_size in 31k 33k; do
+echo "--- Resizing image from $orig_size to 96k ---"
+_make_test_img -F raw -b "$TEST_IMG.base" -o cluster_size=64k "$orig_size"
+$QEMU_IMG resize -f "$IMGFMT" --preallocation=full "$TEST_IMG" 96k
+# The first part of the image should contain data from the backing file
+$QEMU_IO -c "read -q -P 1 0 ${orig_size}" "$TEST_IMG"
+# The resized part of the image should contain zeroes
+$QEMU_IO -c "read -q -P 0 ${orig_size} 63k" "$TEST_IMG"
+# If the image does not have an external data file we can also verify its
+# actual size. The resized image should have 7 clusters:
+# header, L1 table, L2 table, refcount table, refcount block, 2 data
clusters
+if ! _get_data_file "$TEST_IMG" > /dev/null; then
+expected_file_length=$((65536 * 7))
+file_length=$(stat -c '%s' "$TEST_IMG_FILE")
+if [ "$file_length" != "$expected_file_length" ]; then
+echo "ERROR: file length $file_length (expected
$expected_file_length)"
+fi
+fi
+echo
+done
+
# success, all done
echo '*** done'
rm -f $seq.full
diff --git a/tests/qemu-iotests/125.out b/tests/qemu-iotests/125.out
index 596905f533..7f76f7af20 100644
--- a/tests/qemu-iotests/125.out
+++ b/tests/qemu-iotests/125.out
@@ -767,4 +767,13 @@ wrote 2048000/2048000 bytes at offset 0
wrote 81920/81920 bytes at offset 2048000
80 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=raw size=131072
+--- Resizing image from 31k to 96k ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=31744
backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
+Image resized.
+
+--- Resizing image from 33k to 96k ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33792
backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=raw
+Image resized.
+
*** done
--
