diff options
author | Pavel Butsykin <pbutsykin@virtuozzo.com> | 2017-09-29 15:16:13 +0300 |
---|---|---|
committer | Max Reitz <mreitz@redhat.com> | 2017-10-06 16:30:48 +0200 |
commit | 163bc39d2c2921430e5c23f4d0a0966d62f67a02 (patch) | |
tree | d0303bc2a7e3d2d346d8c1d7d361f5a453c8aed4 /block/qcow2-refcount.c | |
parent | 76a2a30a99c670e9ec1b4a5d976868059c6bc258 (diff) | |
download | qemu-163bc39d2c2921430e5c23f4d0a0966d62f67a02.zip qemu-163bc39d2c2921430e5c23f4d0a0966d62f67a02.tar.gz qemu-163bc39d2c2921430e5c23f4d0a0966d62f67a02.tar.bz2 |
qcow2: truncate the tail of the image file after shrinking the image
Now after shrinking the image, at the end of the image file, there might be a
tail that probably will never be used. So we can find the last used cluster and
cut the tail.
Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170929121613.25997-3-pbutsykin@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/qcow2-refcount.c')
-rw-r--r-- | block/qcow2-refcount.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 88d5a3f..aa3fd6c 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -3181,3 +3181,25 @@ out: g_free(reftable_tmp); return ret; } + +int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size) +{ + BDRVQcow2State *s = bs->opaque; + int64_t i; + + for (i = size_to_clusters(s, size) - 1; i >= 0; i--) { + uint64_t refcount; + int ret = qcow2_get_refcount(bs, i, &refcount); + if (ret < 0) { + fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n", + i, strerror(-ret)); + return ret; + } + if (refcount > 0) { + return i; + } + } + qcow2_signal_corruption(bs, true, -1, -1, + "There are no references in the refcount table."); + return -EIO; +} |