From 7cc73776e7f8f87c9b99e021a088e7de52d268ec Mon Sep 17 00:00:00 2001 From: aliguori Date: Sun, 5 Apr 2009 18:16:10 +0000 Subject: qcow2: fix image creation for large, > ~2TB, images (Chris Wright) When creating large disk images w/ qcow2 format, qcow2_create is hard coded to creating a single refcount block. This is insufficient for large images, and will cause qemu-img to segfault as it walks off the end of the refcount block. Keep track of the space needed during image create and create proper number of refcount blocks accordingly. https://bugzilla.redhat.com/show_bug.cgi?id=491943 Signed-off-by: Chris Wright Signed-off-by: Anthony Liguori git-svn-id: svn://svn.savannah.nongnu.org/qemu/branches/stable_0_10@6988 c046a42c-6fe2-441c-8c8c-71466251a162 --- block-qcow2.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/block-qcow2.c b/block-qcow2.c index 894b05a30e..9e69ddf0a0 100644 --- a/block-qcow2.c +++ b/block-qcow2.c @@ -1462,6 +1462,7 @@ static int qcow_create(const char *filename, int64_t total_size, const char *backing_file, int flags) { int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits; + int ref_clusters; QCowHeader header; uint64_t tmp, offset; QCowCreateState s1, *s = &s1; @@ -1502,22 +1503,28 @@ static int qcow_create(const char *filename, int64_t total_size, offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size); s->refcount_table = qemu_mallocz(s->cluster_size); - s->refcount_block = qemu_mallocz(s->cluster_size); s->refcount_table_offset = offset; header.refcount_table_offset = cpu_to_be64(offset); header.refcount_table_clusters = cpu_to_be32(1); offset += s->cluster_size; - - s->refcount_table[0] = cpu_to_be64(offset); s->refcount_block_offset = offset; - offset += s->cluster_size; + + /* count how many refcount blocks needed */ + tmp = offset >> s->cluster_bits; + ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1; + for (i=0; i < ref_clusters; i++) { + s->refcount_table[i] = cpu_to_be64(offset); + offset += s->cluster_size; + } + + s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size); /* update refcounts */ create_refcount_update(s, 0, header_size); create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t)); create_refcount_update(s, s->refcount_table_offset, s->cluster_size); - create_refcount_update(s, s->refcount_block_offset, s->cluster_size); + create_refcount_update(s, s->refcount_block_offset, ref_clusters * s->cluster_size); /* write all the data */ write(fd, &header, sizeof(header)); @@ -1533,7 +1540,7 @@ static int qcow_create(const char *filename, int64_t total_size, write(fd, s->refcount_table, s->cluster_size); lseek(fd, s->refcount_block_offset, SEEK_SET); - write(fd, s->refcount_block, s->cluster_size); + write(fd, s->refcount_block, ref_clusters * s->cluster_size); qemu_free(s->refcount_table); qemu_free(s->refcount_block); -- cgit v1.2.1