Re: [libvirt] [PATCH 08/30] storagefile: Push 'start' into qcow2GetBackingStoreFormat

This is a step towards making this qcow2GetBackingStoreFormat into a generic qcow2 extensions parser Signed-off-by: Cole Robinson <crobinso(a)redhat.com&gt; ---

src/util/virstoragefile.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c index a9a6c3e132..4a3c9df7a2 100644 --- a/src/util/virstoragefile.c +++ b/src/util/virstoragefile.c @@ -430,10 +430,22 @@ static int qcow2GetBackingStoreFormat(int *format, const char *buf, size_t buf_size, - size_t extension_start, size_t extension_end) { - size_t offset = extension_start; + size_t offset; + size_t extension_start; + int version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION); + + if (version < 2) { + /* QCow1 doesn't have the extensions capability + * used to store backing format */ + return 0; + } + + if (version == 2) + extension_start = QCOW2_HDR_TOTAL_SIZE; + else + extension_start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE); /* * The extensions take format of @@ -445,6 +457,7 @@ qcow2GetBackingStoreFormat(int *format, * Unknown extensions can be ignored by skipping * over "length" bytes in the data stream. */ + offset = extension_start; while (offset < (buf_size-8) && offset < (extension_end-8)) { unsigned int magic = virReadBufInt32BE(buf + offset); @@ -487,8 +500,6 @@ qcowXGetBackingStore(char **res, { unsigned long long offset; unsigned int size; - unsigned long long start; - int version; *res = NULL; *format = VIR_STORAGE_FILE_AUTO; @@ -546,18 +557,8 @@ qcowXGetBackingStore(char **res, * is stored at QCOW2v3_HDR_SIZE */ - version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION); - if (version >= 2) { - /* QCow1 doesn't have the extensions capability - * used to store backing format */ - if (version == 2) - start = QCOW2_HDR_TOTAL_SIZE; - else - start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE); - if (qcow2GetBackingStoreFormat(format, buf, buf_size, - start, offset) < 0) - return BACKING_STORE_INVALID; - } + if (qcow2GetBackingStoreFormat(format, buf, buf_size, offset) < 0) + return BACKING_STORE_INVALID; return BACKING_STORE_OK; }