From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from e3i214.smtp2go.com (e3i214.smtp2go.com [158.120.84.214]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9313349AF9 for ; Wed, 4 Mar 2026 08:45:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=158.120.84.214 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772613916; cv=none; b=W23CIFy4ZpJ2sZ/kLRqy9E8VSn7UD4/pN2motGvAoZy1jAhtc6MWN/2ezKukYn3VEt1GdZmk2Z3jH1Pn/4CcethZ71KHJDHpTPuDPCEQR3pWU9+DmyShZTgFe+nYRK2I21SrIQH7by8qLwheTd0unLZhWgd+xNVt4uu0li5dP9E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772613916; c=relaxed/simple; bh=s3YTevfNULOu7OTTUNNxgQc2Xj3CV6y1o+18YQgmD7g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mhwIBLOSKrmrPA4aHvrimymkrtXmHNb1eNF1xKy8AXB/+FWTdvhNA9nDPrjQgy056vhNgv2eUORKqOvdmJqPgPMa7qW198oKYIQt7G8cTVDI6fGdtmlG7/6pWyg/xlFht94Ab6Y/9Xd4XlJygM/Coa6Yc54puIQfCdCjzA11Op0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=triplefau.lt; spf=pass smtp.mailfrom=em510616.triplefau.lt; dkim=pass (2048-bit key) header.d=triplefau.lt header.i=@triplefau.lt header.b=ER1XWPrU; arc=none smtp.client-ip=158.120.84.214 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=triplefau.lt Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=em510616.triplefau.lt Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=triplefau.lt header.i=@triplefau.lt header.b="ER1XWPrU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=triplefau.lt; i=@triplefau.lt; q=dns/txt; s=s510616; t=1772613878; h=from : subject : to : message-id : date; bh=xbrA9YZeGMtG25RjPVPDTCWMxFBr6tAPEzmQlhLARLA=; b=ER1XWPrUq3iKWiiLcMSS9mAs7X5SnJzWPtCFC7iZyCeqNV/f3a7gfqjOAldyZfvD/PDW/ kq7eDNXfDAO8OYy72/QQ+k7JKW3vTNYYsm3n0QmxyN9uVX0vPVmhMAu+xGHpymhbYI4xmuC 90DvcxjHH29PanLguSnZ15xWHVevZd40B48pj/K6xcoVSYxqeXF3qrYbZHQKFYL/pkCVF6/ 62ZnhSFfElSMU+YFuhXRSOoE8PUNguqXI6GN+ynzoCQUI8IFvYP2aOa7uzknYMhU+8fHXtj XjFdrQ2aXXB8HAEUGDe5Gi6I4StW5AmslxhsLT2jRIawX+DjAeuwunb4l6mg== Received: from [10.12.239.196] (helo=localhost) by smtpcorp.com with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.99.1-S2G) (envelope-from ) id 1vxhqL-4o5NDgroe1r-qrjL; Wed, 04 Mar 2026 08:44:33 +0000 Date: Wed, 4 Mar 2026 09:25:27 +0100 From: Remi Pommarel To: Dominique Martinet Cc: Christian Schoenebeck , v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Eric Van Hensbergen , Latchesar Ionkov Subject: Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention Message-ID: References: <7c2a5ba3e229b4e820f0fcd565ca38ab3ca5493f.1772178819.git.repk@triplefau.lt> <4490625.ejJDZkT8p0@weasel> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Report-Abuse: Please forward a copy of this message, including all headers, to Feedback-ID: 510616m:510616apGKSTK:510616sdCwzjTJ0C X-smtpcorp-track: QHEUOEdtPYrl.1niTSwAahWhN.OTLIfgg2ERL On Wed, Mar 04, 2026 at 06:45:35AM +0900, Dominique Martinet wrote: > Christian Schoenebeck wrote on Tue, Mar 03, 2026 at 03:53:47PM +0100: > > > + fsparam_string ("source", Opt_source), > > > + fsparam_u32hex ("debug", Opt_debug), > > > + fsparam_uid ("dfltuid", Opt_dfltuid), > > > + fsparam_gid ("dfltgid", Opt_dfltgid), > > > + fsparam_u32 ("afid", Opt_afid), > > > + fsparam_string ("uname", Opt_uname), > > > + fsparam_string ("aname", Opt_remotename), > > > + fsparam_flag ("nodevmap", Opt_nodevmap), > > > + fsparam_flag ("noxattr", Opt_noxattr), > > > + fsparam_flag ("directio", Opt_directio), > > > + fsparam_flag ("ignoreqv", Opt_ignoreqv), > > > + fsparam_string ("cache", Opt_cache), > > > + fsparam_string ("cachetag", Opt_cachetag), > > > + fsparam_string ("access", Opt_access), > > > + fsparam_flag ("posixacl", Opt_posixacl), > > > + fsparam_u32 ("locktimeout", Opt_locktimeout), > > > + fsparam_flag ("ndentrycache", Opt_ndentrycache), > > > + fsparam_u32 ("ndentrycache", Opt_ndentrycachetmo), > > > > That double entry is surprising. So this mount option is supposed to be used > > like ndentrycache=n for a specific timeout value (in ms) and just ndentrycache > > (without any assignment) for infinite timeout. That's a bit weird. Yes I have seen this used in several other fs (see init_itable mount option for ext4fs or compress one for btrfs). I do agree that is a bit weird but this allow the whole 32bit range for timeout. > > Could make it a s32 and say <0 means infinite? I think we have that > somewhere I did that on previous version, but was afraid that ~20days timeout max value may be too restrictive? I do agree that this is a bit odd though and if you both think s32 is better that is fine with me. > > > Documentation/filesystems/9p.rst should be updated as well BTW. > > > > Nevertheless, like mentioned before, I really think the string "timeout" > > should be used, at least in a user visible mount option. Keep in mind that > > timeouts are a common issue to look at, so it is common to just grep for > > "timeout" in a code base or documentation. An abbrevation like "tmo" or > > leaving it out entirely is for me therefore IMHO inappropriate. > > > > You found "ndentrycachetimeout" too horribly long, or was that again just > > motivated by the code indention below? I personally find those indention > > alignments completely irrelevant, not sure how Dominique sees that. > > Personally I avoid them, as they cost unnecessary time on git blame. > > I rarely use blame at all and it's possible to ignore whitespaces for > blame, but I'd tend to agree here, I don't care if this stays aligned. > > OTOH ndentrycachetimeout as a mount option is a mouthful, > negativetimeout or negtimeout sounds clear enough to me? > I can't think of anything else that'd be negative related > to timeouts, but perhaps it's the lack of sleep speaking No strong opinion on the option name though so any name that suits you is alse fine by me. -- Remi