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Tue, 9 Feb 2021 15:10:44 +0000 Subject: Re: [fuse-devel] [PATCH 0/8] MUSE: Userspace backed MTD v3 To: Richard Weinberger , Miklos Szeredi Cc: Vignesh Raghavendra , fuse-devel , Miquel Raynal , linux-kernel , Boris Brezillon , linux-mtd , Ron Minnich , sven@narfation.org References: <20210124232007.21639-1-richard@nod.at> <563952295.378372.1612881357746.JavaMail.zimbra@nod.at> From: Luca Risolia Message-ID: <3a9c19cf-2c25-a3bf-a200-6d223952797a@studio.unibo.it> Date: Tue, 9 Feb 2021 16:10:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 In-Reply-To: <563952295.378372.1612881357746.JavaMail.zimbra@nod.at> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [151.41.227.128] X-ClientProxiedBy: ZR0P278CA0012.CHEP278.PROD.OUTLOOK.COM (2603:10a6:910:16::22) To DBAPR01MB7109.eurprd01.prod.exchangelabs.com (2603:10a6:10:19a::15) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.1.6] (151.41.227.128) by ZR0P278CA0012.CHEP278.PROD.OUTLOOK.COM (2603:10a6:910:16::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3846.25 via Frontend Transport; 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That would be much appreciated. Thanks On 09/02/21 15:35, Richard Weinberger wrote: > Miklos, > > ----- Ursprüngliche Mail ----- >>> The core goal of MUSE is having the complexity on the userspace side and >>> only a small MTD driver in kernelspace. >>> While playing with different approaches I realized that FUSE offers everything >>> we need. So MUSE is a little like CUSE except that it does not implement a >>> bare character device but an MTD. >> >> Looks fine. > > I'm glad to hear that! > >> I do wonder if MUSE should go to drivers/mtd/ instead. Long term >> goal would be move CUSE to drivers/char and move the transport part of >> fuse into net/fuse leaving only the actual filesystems (fuse and >> virtiofs) under fs/. >> >> But for now just moving the minimal interface needed for MUSE into a >> separate header () would work, I guess. >> >> Do you think that would make sense? > > Yes, I'm all for having MUSE in drivers/mtd/. > > I placed MUSE initially in fs/fuse/ because CUSE was already there and muse.c includes > fuse_i.h. So tried to be as little invasive as possible. > >>> >>> Notes: >>> ------ >>> >>> - OOB support is currently limited. Currently MUSE has no support for processing >>> in- and out-band in the same MTD operation. It is good enough to make JFFS2 >>> happy. This limitation is because FUSE has no support more than one variable >>> length buffer in a FUSE request. >>> At least I didn’t find a good way to pass more than one buffer to a request. >>> Maybe FUSE folks can correct me. :-) >> >> If you look at fuse_do_ioctl() it does variable length input and >> output at the same time. I guess you need something similar to that. > > I'll dig into this! > > Thanks, > //richard > >