diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 48 |
1 files changed, 38 insertions, 10 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 4134bbc253..e91a286333 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -140,6 +140,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) uint64_t data64; uint32_t data32; int64_t offset, snapshots_offset; + int ret; /* compute the size of the snapshots */ offset = 0; @@ -152,6 +153,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) } snapshots_size = offset; + /* Allocate space for the new snapshot list */ snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size); bdrv_flush(bs->file); offset = snapshots_offset; @@ -159,6 +161,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) return offset; } + /* Write all snapshots to the new list */ for(i = 0; i < s->nb_snapshots; i++) { sn = s->snapshots + i; memset(&h, 0, sizeof(h)); @@ -174,34 +177,59 @@ static int qcow2_write_snapshots(BlockDriverState *bs) h.id_str_size = cpu_to_be16(id_str_size); h.name_size = cpu_to_be16(name_size); offset = align_offset(offset, 8); - if (bdrv_pwrite_sync(bs->file, offset, &h, sizeof(h)) < 0) + + ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h)); + if (ret < 0) { goto fail; + } offset += sizeof(h); - if (bdrv_pwrite_sync(bs->file, offset, sn->id_str, id_str_size) < 0) + + ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size); + if (ret < 0) { goto fail; + } offset += id_str_size; - if (bdrv_pwrite_sync(bs->file, offset, sn->name, name_size) < 0) + + ret = bdrv_pwrite(bs->file, offset, sn->name, name_size); + if (ret < 0) { goto fail; + } offset += name_size; } - /* update the various header fields */ + /* + * Update the header to point to the new snapshot table. This requires the + * new table and its refcounts to be stable on disk. + * + * FIXME This should be done with a single write + */ + ret = bdrv_flush(bs); + if (ret < 0) { + goto fail; + } + data64 = cpu_to_be64(snapshots_offset); - if (bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, snapshots_offset), - &data64, sizeof(data64)) < 0) + ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, snapshots_offset), + &data64, sizeof(data64)); + if (ret < 0) { goto fail; + } + data32 = cpu_to_be32(s->nb_snapshots); - if (bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots), - &data32, sizeof(data32)) < 0) + ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots), + &data32, sizeof(data32)); + if (ret < 0) { goto fail; + } /* free the old snapshot table */ qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size); s->snapshots_offset = snapshots_offset; s->snapshots_size = snapshots_size; return 0; - fail: - return -1; + +fail: + return ret; } static void find_new_snapshot_id(BlockDriverState *bs, |