From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 B165FBA42 for ; Sun, 23 Feb 2025 00:28:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740270505; cv=none; b=jp8jJMYRWm9PEicoiSOrqRwc2qJwmbEKCioAWfF/chDnPV3RvJIrTYwFrZMIqF63YpGXvWm0cshjprivKGXWfd4Q36tQ0t+dB3npOrlNZs40MN8QuuMaKMc4KZmkJm9QfRvsod3ek5nFsNLqXHhSSppKwNcfEmvWn3hdFbbPq2w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740270505; c=relaxed/simple; bh=gUh5XueRhxo2oGXBZlZhMx+2L9nt2JOB9xKOxst/v2A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HRFBfw8wJUi2hbiBuLSXP0BHE2KWMmkz0X7fhiDDNW9DeMlnrxLV8F+42Zp34+KCVrgI6QMilbGKeoKJJvxlDL6TmaS0GFV/xGpzRp6XKowMldN30YUYeuytTctdna8q/xR1vOgrqHFrTaJoFxGIZzk1bjg7OkSCq/Sod8Nesls= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=mdVI9b9N; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="mdVI9b9N" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=IQqEOA+t5Ok1x3sSUep9G6VHHIacYQ/KZNCUciq9X5Y=; b=mdVI9b9NXdVHah0b8wbJyid3fr tXSDxxJBBT8ylDp/qcamG03emqTtUHp5jbNTJJNKkij+zKWm2Zs9pYwJVgkvdCIm/7mOD6i3AGTcj qHRX4Cc/k+i19U8EBxzktlhfrJ6v32c7rBHGr6L3DkIlnR6jYyhg9oR1/4jW03t4JyVPob/mN1rCG GkvL+GEsugbE4GujIANjAfEF2bxIePt6DoJza0cPqLWoyP0i6qUxTd72nlC/28g2jMeBHjD5sxcaB 9SCp8beFSzn8lskD3S7qEWk6os7lVKmY1q2lkKCF6rOBiZnEGe9JfTrq5DvXgwiHeCRVLCcfhdAMh 9U7kEHpg==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98 #2 (Red Hat Linux)) id 1tlzr3-00000005hms-1EHK; Sun, 23 Feb 2025 00:28:21 +0000 Date: Sun, 23 Feb 2025 00:28:21 +0000 From: Al Viro To: Miklos Szeredi Cc: linux-fsdevel@vger.kernel.org, Christian Brauner , Bernd Schubert , Laura Promberger , Sam Lewis Subject: Re: [PATCH] fuse: don't truncate cached, mutated symlink Message-ID: <20250223002821.GR1977892@ZenIV> References: <20250220100258.793363-1-mszeredi@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20250220100258.793363-1-mszeredi@redhat.com> Sender: Al Viro On Thu, Feb 20, 2025 at 11:02:58AM +0100, Miklos Szeredi wrote: > The solution is to just remove this truncation. This can cause a > regression in a filesystem that relies on supplying a symlink larger than > the file size, but this is unlikely. If that happens we'd need to make > this behavior conditional. Note, BTW, that page *contents* must not change at all, so truncation is only safe if we have ->i_size guaranteed to be stable. Core pathwalk really counts upon the string remaining immutable, and that does include the string returned by ->get_link().