From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44068) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dVCOv-0007Oj-SJ for qemu-devel@nongnu.org; Wed, 12 Jul 2017 03:49:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dVCOv-0003vH-6r for qemu-devel@nongnu.org; Wed, 12 Jul 2017 03:49:37 -0400 From: Markus Armbruster References: <20170711163748.17817-1-el13635@mail.ntua.gr> Date: Wed, 12 Jul 2017 09:49:20 +0200 In-Reply-To: <20170711163748.17817-1-el13635@mail.ntua.gr> (Manos Pitsidianakis's message of "Tue, 11 Jul 2017 19:37:44 +0300") Message-ID: <87tw2iaydb.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH v4 0/4] block: Block driver callbacks fixes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Manos Pitsidianakis Cc: qemu-devel , Kevin Wolf , Alberto Garcia , qemu-block , Max Reitz , Stefan Hajnoczi Manos Pitsidianakis writes: > This series makes implementing some of the bdrv_* callbacks easier for block > filters by passing requests to bs->file if bs->drv doesn't implement it instead > of failing, and adding default bdrv_co_get_block_status() implementations. > > This is based against Kevin Wolf's block branch, commit > da4bd74d2450ab72a7c26bbabb10c6a287dd043e Haven't seen BlockDriver member is_filter before. Interesting. It's documentation /* set to true if the BlockDriver is a block filter */ bool is_filter; is seriously lacking. What does it *mean* to be a block filter? Which block layer facilities are affected, and how? Observation: driver "raw" is filter-like in the sense that all it does is pass along method arguments and results. Can't say whether that makes it a filter in the sense of is_filter, because "the sense of is_filter" is nebulous to me :)