diff options
| -rw-r--r-- | block/qcow2.c | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 3954cf1398..984264b3ea 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -124,12 +124,12 @@ static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset, #ifdef DEBUG_EXT printf("Qcow2: Got format extension %s\n", bs->backing_format); #endif - offset += ((ext.len + 7) & ~7); + offset = ((offset + ext.len + 7) & ~7); break; default: /* unknown magic -- just skip it */ - offset += ((ext.len + 7) & ~7); + offset = ((offset + ext.len + 7) & ~7); break; } } @@ -738,6 +738,7 @@ static int qcow_create2(const char *filename, int64_t total_size, int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits; int ref_clusters, backing_format_len = 0; + int rounded_ext_bf_len = 0; QCowHeader header; uint64_t tmp, offset; QCowCreateState s1, *s = &s1; @@ -759,8 +760,9 @@ static int qcow_create2(const char *filename, int64_t total_size, if (backing_format) { ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT; backing_format_len = strlen(backing_format); - ext_bf.len = (backing_format_len + 7) & ~7; - header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7); + ext_bf.len = backing_format_len; + rounded_ext_bf_len = (sizeof(ext_bf) + ext_bf.len + 7) & ~7; + header_size += rounded_ext_bf_len; } header.backing_file_offset = cpu_to_be64(header_size); backing_filename_len = strlen(backing_file); @@ -828,15 +830,15 @@ static int qcow_create2(const char *filename, int64_t total_size, if (backing_file) { if (backing_format_len) { char zero[16]; - int d = ext_bf.len - backing_format_len; + int padding = rounded_ext_bf_len - (ext_bf.len + sizeof(ext_bf)); memset(zero, 0, sizeof(zero)); cpu_to_be32s(&ext_bf.magic); cpu_to_be32s(&ext_bf.len); write(fd, &ext_bf, sizeof(ext_bf)); write(fd, backing_format, backing_format_len); - if (d>0) { - write(fd, zero, d); + if (padding > 0) { + write(fd, zero, padding); } } write(fd, backing_file, backing_filename_len); |