diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 20 | ||||
| -rw-r--r-- | block/qcow2.c | 25 | ||||
| -rwxr-xr-x | tests/qemu-iotests/061 | 35 | ||||
| -rw-r--r-- | tests/qemu-iotests/061.out | 28 |
4 files changed, 101 insertions, 7 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 82c32d4..2756b37 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -23,6 +23,7 @@ */ #include "qemu/osdep.h" +#include "sysemu/block-backend.h" #include "qapi/error.h" #include "qcow2.h" #include "qemu/bswap.h" @@ -775,10 +776,21 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) } if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) { - error_report("qcow2: Loading snapshots with different disk " - "size is not implemented"); - ret = -ENOTSUP; - goto fail; + BlockBackend *blk = blk_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL, + &local_err); + if (!blk) { + error_report_err(local_err); + ret = -ENOTSUP; + goto fail; + } + + ret = blk_truncate(blk, sn->disk_size, true, PREALLOC_MODE_OFF, 0, + &local_err); + blk_unref(blk); + if (ret < 0) { + error_report_err(local_err); + goto fail; + } } /* diff --git a/block/qcow2.c b/block/qcow2.c index 0edc7f4..3e8b3d0 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3989,9 +3989,12 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, qemu_co_mutex_lock(&s->lock); - /* cannot proceed if image has snapshots */ - if (s->nb_snapshots) { - error_setg(errp, "Can't resize an image which has snapshots"); + /* + * Even though we store snapshot size for all images, it was not + * required until v3, so it is not safe to proceed for v2. + */ + if (s->nb_snapshots && s->qcow_version < 3) { + error_setg(errp, "Can't resize a v2 image which has snapshots"); ret = -ENOTSUP; goto fail; } @@ -5005,6 +5008,7 @@ static int qcow2_downgrade(BlockDriverState *bs, int target_version, BDRVQcow2State *s = bs->opaque; int current_version = s->qcow_version; int ret; + int i; /* This is qcow2_downgrade(), not qcow2_upgrade() */ assert(target_version < current_version); @@ -5022,6 +5026,21 @@ static int qcow2_downgrade(BlockDriverState *bs, int target_version, return -ENOTSUP; } + /* + * If any internal snapshot has a different size than the current + * image size, or VM state size that exceeds 32 bits, downgrading + * is unsafe. Even though we would still use v3-compliant output + * to preserve that data, other v2 programs might not realize + * those optional fields are important. + */ + for (i = 0; i < s->nb_snapshots; i++) { + if (s->snapshots[i].vm_state_size > UINT32_MAX || + s->snapshots[i].disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) { + error_setg(errp, "Internal snapshots prevent downgrade of image"); + return -ENOTSUP; + } + } + /* clear incompatible features */ if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { ret = qcow2_mark_clean(bs); diff --git a/tests/qemu-iotests/061 b/tests/qemu-iotests/061 index ce285d3..10eb243 100755 --- a/tests/qemu-iotests/061 +++ b/tests/qemu-iotests/061 @@ -112,6 +112,41 @@ $QEMU_IO -c "read -P 0x2a 42M 64k" "$TEST_IMG" | _filter_qemu_io _check_test_img echo +echo "=== Testing resize with snapshots ===" +echo +_make_test_img -o "compat=0.10" 32M +$QEMU_IO -c "write -P 0x2a 24M 64k" "$TEST_IMG" | _filter_qemu_io +$QEMU_IMG snapshot -c foo "$TEST_IMG" +$QEMU_IMG resize "$TEST_IMG" 64M && + echo "unexpected pass" +$PYTHON qcow2.py "$TEST_IMG" dump-header | grep '^\(version\|size\|nb_snap\)' + +$QEMU_IMG amend -o "compat=1.1,size=128M" "$TEST_IMG" || + echo "unexpected fail" +$PYTHON qcow2.py "$TEST_IMG" dump-header | grep '^\(version\|size\|nb_snap\)' + +$QEMU_IMG snapshot -c bar "$TEST_IMG" +$QEMU_IMG resize --shrink "$TEST_IMG" 64M || + echo "unexpected fail" +$PYTHON qcow2.py "$TEST_IMG" dump-header | grep '^\(version\|size\|nb_snap\)' + +$QEMU_IMG amend -o "compat=0.10,size=32M" "$TEST_IMG" && + echo "unexpected pass" +$PYTHON qcow2.py "$TEST_IMG" dump-header | grep '^\(version\|size\|nb_snap\)' + +$QEMU_IMG snapshot -a bar "$TEST_IMG" || + echo "unexpected fail" +$PYTHON qcow2.py "$TEST_IMG" dump-header | grep '^\(version\|size\|nb_snap\)' + +$QEMU_IMG snapshot -d bar "$TEST_IMG" +$QEMU_IMG amend -o "compat=0.10,size=32M" "$TEST_IMG" || + echo "unexpected fail" +$PYTHON qcow2.py "$TEST_IMG" dump-header | grep '^\(version\|size\|nb_snap\)' + +_check_test_img + + +echo echo "=== Testing dirty lazy_refcounts=off ===" echo _make_test_img -o "compat=1.1,lazy_refcounts=on" 64M diff --git a/tests/qemu-iotests/061.out b/tests/qemu-iotests/061.out index 413cc4e..5a8d36d 100644 --- a/tests/qemu-iotests/061.out +++ b/tests/qemu-iotests/061.out @@ -271,6 +271,34 @@ read 65536/65536 bytes at offset 44040192 64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) No errors were found on the image. +=== Testing resize with snapshots === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=33554432 +wrote 65536/65536 bytes at offset 25165824 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +qemu-img: Can't resize a v2 image which has snapshots +version 2 +size 33554432 +nb_snapshots 1 +version 3 +size 134217728 +nb_snapshots 1 +Image resized. +version 3 +size 67108864 +nb_snapshots 2 +qemu-img: Internal snapshots prevent downgrade of image +version 3 +size 33554432 +nb_snapshots 2 +version 3 +size 134217728 +nb_snapshots 2 +version 2 +size 33554432 +nb_snapshots 1 +No errors were found on the image. + === Testing dirty lazy_refcounts=off === Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 |