diff options
Diffstat (limited to 'block/qcow2.c')
| -rw-r--r-- | block/qcow2.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 64bb7b8a1f..8bfb094e53 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2079,6 +2079,15 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) goto finish; } + refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, + refcount_bits); + if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { + error_setg(errp, "Refcount width must be a power of two and may not " + "exceed 64 bits"); + ret = -EINVAL; + goto finish; + } + if (version < 3 && refcount_bits != 16) { error_setg(errp, "Different refcount widths than 16 bits require " "compatibility level 1.1 or above (use compat=1.1 or " @@ -2712,6 +2721,9 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, lazy_refcounts); + } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { + error_report("Cannot change refcount entry width"); + return -ENOTSUP; } else { /* if this assertion fails, this probably means a new option was * added without having it covered here */ @@ -2881,6 +2893,12 @@ static QemuOptsList qcow2_create_opts = { .help = "Postpone refcount updates", .def_value_str = "off" }, + { + .name = BLOCK_OPT_REFCOUNT_BITS, + .type = QEMU_OPT_NUMBER, + .help = "Width of a reference count entry in bits", + .def_value_str = "16" + }, { /* end of list */ } } }; |