LUKS encryption reserves clusters for its own payload data. The size of
this area must be included in the qemu-img measure calculation so that
we arrive at the correct minimum required image size.
(Ab)use the qcrypto_block_create() API to determine the payload
overhead. We discard the payload data that qcrypto thinks will be
written to the image.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block/qcow2.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 4897abae5e..7ab93a5d2f 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4231,6 +4231,24 @@ static coroutine_fn int
qcow2_co_flush_to_os(BlockDriverState *bs)
return ret;
}
+static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block,
+ size_t headerlen, void *opaque, Error **errp)
+{
+ size_t *headerlenp = opaque;
+
+ /* Stash away the payload size */
+ *headerlenp = headerlen;
+ return 0;
+}
+
+static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block,
+ size_t offset, const uint8_t *buf, size_t buflen,
+ void *opaque, Error **errp)
+{
+ /* Discard the bytes, we're not actually writing to an image */
+ return buflen;
+}
+
static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
Error **errp)
{
@@ -4240,11 +4258,13 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts,
BlockDriverState *in_bs,
uint64_t virtual_size; /* disk size as seen by guest */
uint64_t refcount_bits;
uint64_t l2_tables;
+ uint64_t luks_payload_size = 0;
size_t cluster_size;
int version;
char *optstr;
PreallocMode prealloc;
bool has_backing_file;
+ bool has_luks;
/* Parse image creation options */
cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err);
@@ -4274,6 +4294,35 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts,
BlockDriverState *in_bs,
has_backing_file = !!optstr;
g_free(optstr);
+ optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT);
+ has_luks = optstr && strcmp(optstr, "luks") == 0;
+ g_free(optstr);
+
+ if (has_luks) {
+ QCryptoBlockCreateOptions cryptoopts = {
+ .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
+ };
+ QCryptoBlock *crypto;
+ size_t headerlen;
+
+ optstr = qemu_opt_get_del(opts, "encrypt.key-secret");
+ cryptoopts.u.luks.has_key_secret = !!optstr;
+ cryptoopts.u.luks.key_secret = optstr;
+
+ crypto = qcrypto_block_create(&cryptoopts, "encrypt.",
+ qcow2_measure_crypto_hdr_init_func,
+ qcow2_measure_crypto_hdr_write_func,
+ &headerlen, &local_err);
+
+ g_free(optstr);
+ if (!crypto) {
+ goto err;
+ }
+ qcrypto_block_free(crypto);
+
+ luks_payload_size = ROUND_UP(headerlen, cluster_size);
+ }
+
virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
virtual_size = ROUND_UP(virtual_size, cluster_size);
@@ -4344,7 +4393,7 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts,
BlockDriverState *in_bs,
info = g_new(BlockMeasureInfo, 1);
info->fully_allocated =
qcow2_calc_prealloc_size(virtual_size, cluster_size,
- ctz32(refcount_bits));
+ ctz32(refcount_bits)) + luks_payload_size;
/* Remove data clusters that are not required. This overestimates the
* required size because metadata needed for the fully allocated file is
--
2.20.1
