From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49282) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ek9Dy-00084M-5W for qemu-devel@nongnu.org; Fri, 09 Feb 2018 09:00:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ek9Dv-0003Y0-4l for qemu-devel@nongnu.org; Fri, 09 Feb 2018 09:00:22 -0500 Date: Fri, 9 Feb 2018 15:00:07 +0100 From: Kevin Wolf Message-ID: <20180209140007.GC3998@localhost.localdomain> References: <20180208192328.16550-1-kwolf@redhat.com> <20180208192328.16550-5-kwolf@redhat.com> <78712c7a-a8f0-5d7b-d1f5-d37fcb178655@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <78712c7a-a8f0-5d7b-d1f5-d37fcb178655@redhat.com> Subject: Re: [Qemu-devel] [PATCH 04/27] qcow2: Pass BlockdevCreateOptions to qcow2_create2() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: qemu-block@nongnu.org, mreitz@redhat.com, pkrempa@redhat.com, jcody@redhat.com, jdurgin@redhat.com, mitake.hitoshi@lab.ntt.co.jp, namei.unix@gmail.com, qemu-devel@nongnu.org Am 09.02.2018 um 00:29 hat Eric Blake geschrieben: > On 02/08/2018 01:23 PM, Kevin Wolf wrote: > > All of the simple options are now passed to qcow2_create2() in a > > BlockdevCreateOptions object. Still missing: node-name and the > > encryption options. > > > > Signed-off-by: Kevin Wolf > > --- > > block/qcow2.c | 190 ++++++++++++++++++++++++++++++++++++++++++++++------------ > > 1 file changed, 152 insertions(+), 38 deletions(-) > > > > > -static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp) > > +static bool validate_cluster_size(size_t cluster_size, Error **errp) > > { > > - size_t cluster_size; > > - int cluster_bits; > > - > > - cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, > > - DEFAULT_CLUSTER_SIZE); > > - cluster_bits = ctz32(cluster_size); > > + int cluster_bits = ctz32(cluster_size); > > if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || > > (1 << cluster_bits) != cluster_size) > > Pre-existing, but why are we manually calling ctz32() instead of using > is_power_of_2()? Probably because is_power_of_2() is newer than this code. Also, if we don't call ctz32(), we'd have to use (1 << MIN_CLUSTER_BITS) and (1 << MAX_CLUSTER_BITS), so I'm not sure if that would be better. > > @@ -2720,10 +2726,92 @@ static int qcow2_create2(BlockDriverState *bs, int64_t total_size, > > */ > > BlockBackend *blk; > > QCowHeader *header; > > + size_t cluster_size; > > + int version; > > + int refcount_order; > > uint64_t* refcount_table; > > Error *local_err = NULL; > > int ret; > > + /* Validate options and set default values */ > > + assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2); > > + qcow2_opts = &create_options->u.qcow2; > > + > > + if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) { > > + error_setg(errp, "Image size must be a multiple of 512 bytes"); > > + ret = -EINVAL; > > + goto out; > > + } > > This check looks new. Does it really belong in this patch? And it does NOT > match what qemu-img can currently do, nor the fact that qcow2 supports > byte-based addressing: > > $ qemu-img create -f qcow2 tmp 12345 > Formatting 'tmp', fmt=qcow2 size=12345 cluster_size=65536 lazy_refcounts=off > refcount_bits=16 You're ignoring the result of this command: $ ./qemu-img create -f qcow2 /tmp/test.qcow2 12345 Formatting '/tmp/test.qcow2', fmt=qcow2 size=12345 cluster_size=65536 lazy_refcounts=off refcount_bits=16 $ ./qemu-img info -f qcow2 /tmp/test.qcow2 image: /tmp/test.qcow2 file format: qcow2 virtual size: 13K (12800 bytes) disk size: 196K cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false As you can see, the size got silently rounded up to the next 512 bytes. qcow2_create() still does the same even after this patch, but I chose not to extend the magic rounding to the QMP command. In the protocol drivers, I generally just allow byte granularity image sizes, but qcow2 does use sectors internally, so it felt safer to require 512 byte alignment in qcow2. > > + if (!qcow2_opts->has_lazy_refcounts) { > > + qcow2_opts->lazy_refcounts = false; > > + } > > + if (version < 3 && qcow2_opts->lazy_refcounts) { > > + error_setg(errp, "Lazy refcounts only supported with compatibility " > > + "level 1.1 and above (use compat=1.1 or greater)"); > > Do we want to reword this error message at all, now that QMP spells it 'v3'? > Should qemu-img be taught to accept 'compat=v3' as a synonym to > 'compat=1.1'? Actually, it does accept 'v3' when the whole series is applied, and the message is changed in a later patch that enables this. Kevin