A few drive-by comments... Eric Blake <[email protected]> writes:
> On 10/24/2016 02:27 PM, Ashijeet Acharya wrote: >> Introduce new object 'BlockdevOptionsNFS' in qapi/block-core.json to >> support blockdev-add for NFS network protocol driver. Also make a new >> struct NFSServer to support tcp connection. >> >> Signed-off-by: Ashijeet Acharya <[email protected]> >> --- >> qapi/block-core.json | 56 >> ++++++++++++++++++++++++++++++++++++++++++++++++---- >> 1 file changed, 52 insertions(+), 4 deletions(-) >> >> diff --git a/qapi/block-core.json b/qapi/block-core.json >> index 9d797b8..3ab028d 100644 >> --- a/qapi/block-core.json >> +++ b/qapi/block-core.json >> @@ -1714,9 +1714,9 @@ >> { 'enum': 'BlockdevDriver', >> 'data': [ 'archipelago', 'blkdebug', 'blkverify', 'bochs', 'cloop', >> 'dmg', 'file', 'ftp', 'ftps', 'gluster', 'host_cdrom', >> - 'host_device', 'http', 'https', 'luks', 'null-aio', 'null-co', >> - 'parallels', 'qcow', 'qcow2', 'qed', 'quorum', 'raw', >> - 'replication', 'tftp', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat' ] } >> + 'host_device', 'http', 'https', 'luks', 'nfs', 'null-aio', >> + 'null-co', 'parallels', 'qcow', 'qcow2', 'qed', 'quorum', 'raw', >> + 'replication', 'tftp', 'vdi', 'vhdx', 'vmdk', 'vpc', 'vvfat' ] } > > Missing a comment that 'nfs' is since 2.8. > >> ## >> +# @NFSServer >> +# >> +# Captures the address of the socket >> +# >> +# @type: transport type used for NFS (only TCP supported) >> +# >> +# @host: host part of the address >> +# >> +# Since 2.8 >> +## >> +{ 'struct': 'NFSServer', >> + 'data': { 'type': 'str', > > Please make this an enum, instead of an open-coded string. It's okay if > the enum only has one value 'tcp' for now; but using an enum will make > it introspectable if we later add a second transport, unlike what we get > with an open-coded string. Yes. When a JSON string has a compile-time fixed set of values, 'str' is generally wrong. > Must 'type' be mandatory if it must always be 'tcp'? > >> + 'host': 'str' } } >> + >> +## >> +# @BlockdevOptionsNfs >> +# >> +# Driver specific block device option for NFS >> +# >> +# @server: host address >> +# >> +# @path: path of the image on the host >> +# >> +# @uid: #optional UID value to use when talking to the server >> +# >> +# @gid: #optional GID value to use when talking to the server > > Do we want to allow string names in addition to numeric uid/gid values? > I'm not sure if NFS has name-based id mapping, but it's food for thought > on whether we need to use an alternate type here (alternate between > integer id and string name), or leave this as is. As far as I know, NFS4 supports user and group names. On Linux, see rpc.idmapd(8). How the name support affects C code I can't say. If it's transparent, i.e. you simply use local UID/GID, and the mapping happens below the hood, then we'd have to translate string values to local UID/GID by the usual means. Looks like a minor convenience feature on first glance. However, QMP is a *network* protocol. A remote client can't easily do this translation. Consider a GUI like virt-manager: I guess we'd rather support user and group names there. But if we do, and QMP doesn't, either virt-manager or libvirt need to map to numeric IDs. Easy enough when running on the host, probably impractical when not. If we permit string values, are @uid and @gid still appropriate names? The user name is not the user ID, it just maps to it. >> +# >> +# @tcp-syncnt: #optional number of SYNs during the session establishment > > Would tcp-syn-count be any more legible? We generally write out things in long hand in the QAPI schema. > What is the default when omitted? Whenever you write #optional, you must explain the default. When the default is a fixed value, specify it. When the system picks a default, state that, and think hard about what you need to specify on how the system picks. >> +# >> +# @readahead: #optional set the readahead size in bytes @read-ahead > What's the default when omitted? > >> +# >> +# @pagecache: #optional set the pagecache size in bytes @page-cache > Default? > >> +# >> +# @debug: #optional set the NFS debug level (max 2) > > Presumably default 0? @BlockdevOptionsGluster calls this @debug-level. >> +# >> +# Since 2.8 >> +## >> +{ 'struct': 'BlockdevOptionsNfs', >> + 'data': { 'server': 'NFSServer', >> + 'path': 'str', >> + '*uid': 'int', >> + '*gid': 'int', >> + '*tcp-syncnt': 'int', >> + '*readahead': 'int', >> + '*pagecache': 'int', >> + '*debug': 'int' } } >> +
