It's useful to know how much space can be occupied by qcow2 persistent bitmaps, even though such metadata is unrelated to the guest-visible data. Report this value as an additional field. Update iotest 190 to cover it and a portion of the just-added qemu-img bitmap command.
The addition of a new field demonstrates why we should always zero-initialize qapi C structs; while the qcow2 driver still fully populates all fields, the raw and crypto drivers had to be tweaked. See also: https://bugzilla.redhat.com/1779904 Reported-by: Nir Soffer <nsof...@redhat.com> Signed-off-by: Eric Blake <ebl...@redhat.com> --- qapi/block-core.json | 15 ++++++++++----- block/crypto.c | 2 +- block/qcow2.c | 29 ++++++++++++++++++++++++++++- block/raw-format.c | 2 +- qemu-img.c | 3 +++ tests/qemu-iotests/190 | 15 +++++++++++++-- tests/qemu-iotests/190.out | 13 ++++++++++++- 7 files changed, 68 insertions(+), 11 deletions(-) diff --git a/qapi/block-core.json b/qapi/block-core.json index 943df1926a91..b47c6d69ba27 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -633,18 +633,23 @@ # efficiently so file size may be smaller than virtual disk size. # # The values are upper bounds that are guaranteed to fit the new image file. -# Subsequent modification, such as internal snapshot or bitmap creation, may -# require additional space and is not covered here. +# Subsequent modification, such as internal snapshot or further bitmap +# creation, may require additional space and is not covered here. # -# @required: Size required for a new image file, in bytes. +# @required: Size required for a new image file, in bytes, when copying just +# guest-visible contents. # # @fully-allocated: Image file size, in bytes, once data has been written -# to all sectors. +# to all sectors, when copying just guest-visible contents. +# +# @bitmaps: Additional size required for bitmap metadata not directly used +# for guest contents, when that metadata can be copied in addition +# to guest contents. (since 5.1) # # Since: 2.10 ## { 'struct': 'BlockMeasureInfo', - 'data': {'required': 'int', 'fully-allocated': 'int'} } + 'data': {'required': 'int', 'fully-allocated': 'int', '*bitmaps': 'int'} } ## # @query-block: diff --git a/block/crypto.c b/block/crypto.c index d577f89659fa..4e0f3ec97f0e 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -535,7 +535,7 @@ static BlockMeasureInfo *block_crypto_measure(QemuOpts *opts, * Unallocated blocks are still encrypted so allocation status makes no * difference to the file size. */ - info = g_new(BlockMeasureInfo, 1); + info = g_new0(BlockMeasureInfo, 1); info->fully_allocated = luks_payload_size + size; info->required = luks_payload_size + size; return info; diff --git a/block/qcow2.c b/block/qcow2.c index b524b0c53f84..9fd650928016 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -4657,6 +4657,7 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, PreallocMode prealloc; bool has_backing_file; bool has_luks; + uint64_t bitmaps_size = 0; /* size occupied by bitmaps in in_bs */ /* Parse image creation options */ cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err); @@ -4732,6 +4733,8 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, /* Account for input image */ if (in_bs) { + BdrvDirtyBitmap *bm; + size_t bitmap_overhead = 0; int64_t ssize = bdrv_getlength(in_bs); if (ssize < 0) { error_setg_errno(&local_err, -ssize, @@ -4739,6 +4742,28 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, goto err; } + FOR_EACH_DIRTY_BITMAP(in_bs, bm) { + if (bdrv_dirty_bitmap_get_persistence(bm)) { + const char *name = bdrv_dirty_bitmap_name(bm); + uint32_t granularity = bdrv_dirty_bitmap_granularity(bm); + uint64_t bmbits = DIV_ROUND_UP(bdrv_dirty_bitmap_size(bm), + granularity); + uint64_t bmclusters = DIV_ROUND_UP(DIV_ROUND_UP(bmbits, + CHAR_BIT), + cluster_size); + + /* Assume the entire bitmap is allocated */ + bitmaps_size += bmclusters * cluster_size; + /* Also reserve space for the bitmap table entries */ + bitmaps_size += ROUND_UP(bmclusters * sizeof(uint64_t), + cluster_size); + /* Guess at contribution to bitmap directory size */ + bitmap_overhead += ROUND_UP(strlen(name) + 24, + sizeof(uint64_t)); + } + } + bitmaps_size += ROUND_UP(bitmap_overhead, cluster_size); + virtual_size = ROUND_UP(ssize, cluster_size); if (has_backing_file) { @@ -4785,7 +4810,7 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, required = virtual_size; } - info = g_new(BlockMeasureInfo, 1); + info = g_new0(BlockMeasureInfo, 1); info->fully_allocated = qcow2_calc_prealloc_size(virtual_size, cluster_size, ctz32(refcount_bits)) + luks_payload_size; @@ -4795,6 +4820,8 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, * still counted. */ info->required = info->fully_allocated - virtual_size + required; + info->has_bitmaps = !!bitmaps_size; + info->bitmaps = bitmaps_size; return info; err: diff --git a/block/raw-format.c b/block/raw-format.c index 93b25e1b6b0b..4bb54f4ac6c5 100644 --- a/block/raw-format.c +++ b/block/raw-format.c @@ -346,7 +346,7 @@ static BlockMeasureInfo *raw_measure(QemuOpts *opts, BlockDriverState *in_bs, BDRV_SECTOR_SIZE); } - info = g_new(BlockMeasureInfo, 1); + info = g_new0(BlockMeasureInfo, 1); info->required = required; /* Unallocated sectors count towards the file size in raw images */ diff --git a/qemu-img.c b/qemu-img.c index 02ebd870faa1..e1127273f21e 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -5207,6 +5207,9 @@ static int img_measure(int argc, char **argv) if (output_format == OFORMAT_HUMAN) { printf("required size: %" PRIu64 "\n", info->required); printf("fully allocated size: %" PRIu64 "\n", info->fully_allocated); + if (info->has_bitmaps) { + printf("bitmaps size: %" PRIu64 "\n", info->bitmaps); + } } else { dump_json_block_measure_info(info); } diff --git a/tests/qemu-iotests/190 b/tests/qemu-iotests/190 index 6d41650438e1..cae643149a01 100755 --- a/tests/qemu-iotests/190 +++ b/tests/qemu-iotests/190 @@ -2,7 +2,7 @@ # # qemu-img measure sub-command tests on huge qcow2 files # -# Copyright (C) 2017 Red Hat, Inc. +# Copyright (C) 2017-2020 Red Hat, 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 @@ -42,7 +42,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15 _supported_fmt qcow2 _supported_proto file -echo "== Huge file ==" +echo "== Huge file without bitmaps ==" echo _make_test_img -o 'cluster_size=2M' 2T @@ -51,6 +51,17 @@ $QEMU_IMG measure -O raw -f qcow2 "$TEST_IMG" $QEMU_IMG measure -O qcow2 -o cluster_size=64k -f qcow2 "$TEST_IMG" $QEMU_IMG measure -O qcow2 -o cluster_size=2M -f qcow2 "$TEST_IMG" +echo +echo "== Huge file with bitmaps ==" +echo + +$QEMU_IMG bitmap --add --granularity 512 -f qcow2 "$TEST_IMG" b1 +$QEMU_IMG bitmap --add -g 2M -f qcow2 "$TEST_IMG" b2 + +$QEMU_IMG measure -O raw -f qcow2 "$TEST_IMG" +$QEMU_IMG measure -O qcow2 -o cluster_size=64k -f qcow2 "$TEST_IMG" +$QEMU_IMG measure -O qcow2 -o cluster_size=2M -f qcow2 "$TEST_IMG" + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/190.out b/tests/qemu-iotests/190.out index d001942002db..11962f972429 100644 --- a/tests/qemu-iotests/190.out +++ b/tests/qemu-iotests/190.out @@ -1,5 +1,5 @@ QA output created by 190 -== Huge file == +== Huge file without bitmaps == Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=2199023255552 required size: 2199023255552 @@ -8,4 +8,15 @@ required size: 335806464 fully allocated size: 2199359062016 required size: 18874368 fully allocated size: 2199042129920 + +== Huge file with bitmaps == + +required size: 2199023255552 +fully allocated size: 2199023255552 +required size: 335806464 +fully allocated size: 2199359062016 +bitmaps size: 537198592 +required size: 18874368 +fully allocated size: 2199042129920 +bitmaps size: 545259520 *** done -- 2.26.2