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qemu-img: Fail fast on convert --bitmaps with inconsistent bitmap

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Waiting until the end of the convert operation (a potentially
time-consuming task) to finally detect that we can't copy a bitmap is
bad, comparing to failing fast up front.  Furthermore, this prevents
us from leaving a file behind with a bitmap that is not marked as
inconsistent even though it does not have sane contents.

This fixes the problems exposed in the previous patch to the iotest:
it adds a fast failure up front, and even if we don't fail early, it
ensures that any bitmap we add but do not properly populate is removed
again rather than left behind incomplete.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210709153951.2801666-3-eblake@redhat.com>
[eblake: add a hint to the warning message, simplify name computation]
Reviewed-by: Nir Soffer <nsoffer@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This commit is contained in:
Eric Blake 2021-07-09 10:39:50 -05:00
parent 94075c28ee
commit 74a4320f30
3 changed files with 30 additions and 23 deletions
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29
qemu-img.c
View File

@ -2101,6 +2101,29 @@ static int convert_do_copy(ImgConvertState *s)
return s->ret;
}
/* Check that bitmaps can be copied, or output an error */
static int convert_check_bitmaps(BlockDriverState *src)
{
BdrvDirtyBitmap *bm;
if (!bdrv_supports_persistent_dirty_bitmap(src)) {
error_report("Source lacks bitmap support");
return -1;
}
FOR_EACH_DIRTY_BITMAP(src, bm) {
if (!bdrv_dirty_bitmap_get_persistence(bm)) {
continue;
}
if (bdrv_dirty_bitmap_inconsistent(bm)) {
error_report("Cannot copy inconsistent bitmap '%s'",
bdrv_dirty_bitmap_name(bm));
error_printf("Try 'qemu-img bitmap --remove' to delete it\n");
return -1;
}
}
return 0;
}
static int convert_copy_bitmaps(BlockDriverState *src, BlockDriverState *dst)
{
BdrvDirtyBitmap *bm;
@ -2127,6 +2150,7 @@ static int convert_copy_bitmaps(BlockDriverState *src, BlockDriverState *dst)
&err);
if (err) {
error_reportf_err(err, "Failed to populate bitmap %s: ", name);
qmp_block_dirty_bitmap_remove(dst->node_name, name, NULL);
return -1;
}
}
@ -2554,9 +2578,8 @@ static int img_convert(int argc, char **argv)
ret = -1;
goto out;
}
if (!bdrv_supports_persistent_dirty_bitmap(blk_bs(s.src[0]))) {
error_report("Source lacks bitmap support");
ret = -1;
ret = convert_check_bitmaps(blk_bs(s.src[0]));
if (ret < 0) {
goto out;
}
}

3
tests/qemu-iotests/tests/qemu-img-bitmaps
View File

@ -140,11 +140,10 @@ $QEMU_IO -c abort "$TEST_IMG" 2>/dev/null
$QEMU_IMG bitmap --add "$TEST_IMG" b4
$QEMU_IMG bitmap --remove "$TEST_IMG" b1
_img_info --format-specific | _filter_irrelevant_img_info
# Proof that we fail fast if bitmaps can't be copied
echo
$QEMU_IMG convert --bitmaps -O qcow2 "$TEST_IMG" "$TEST_IMG.copy" &&
echo "unexpected success"
# Bug - even though we failed at conversion, we left a file around with
# a bitmap marked as not corrupt
TEST_IMG=$TEST_IMG.copy _img_info --format-specific \
| _filter_irrelevant_img_info

21
tests/qemu-iotests/tests/qemu-img-bitmaps.out
View File

@ -144,22 +144,7 @@ Format specific information:
granularity: 65536
corrupt: false
qemu-img: Failed to populate bitmap b0: Bitmap 'b0' is inconsistent and cannot be used
Try block-dirty-bitmap-remove to delete this bitmap from disk
image: TEST_DIR/t.IMGFMT.copy
file format: IMGFMT
virtual size: 10 MiB (10485760 bytes)
cluster_size: 65536
Format specific information:
bitmaps:
[0]:
flags:
name: b0
granularity: 65536
[1]:
flags:
[0]: auto
name: b4
granularity: 65536
corrupt: false
qemu-img: Cannot copy inconsistent bitmap 'b0'
Try 'qemu-img bitmap --remove' to delete it
qemu-img: Could not open 'TEST_DIR/t.IMGFMT.copy': Could not open 'TEST_DIR/t.IMGFMT.copy': No such file or directory
*** done