From owner-svn-src-head@freebsd.org Tue May 19 15:37:58 2020 Return-Path: Delivered-To: svn-src-head@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id EA1CB2DC905; Tue, 19 May 2020 15:37:58 +0000 (UTC) (envelope-from kevans@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49RKlV5wZGz3TVt; Tue, 19 May 2020 15:37:58 +0000 (UTC) (envelope-from kevans@freebsd.org) Received: from mail-qt1-f180.google.com (mail-qt1-f180.google.com [209.85.160.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) (Authenticated sender: kevans) by smtp.freebsd.org (Postfix) with ESMTPSA id C13B82C85C; Tue, 19 May 2020 15:37:58 +0000 (UTC) (envelope-from kevans@freebsd.org) Received: by mail-qt1-f180.google.com with SMTP id v4so11504855qte.3; Tue, 19 May 2020 08:37:58 -0700 (PDT) X-Gm-Message-State: AOAM533T+1IrjoneEohoT9SRdZQ9i3IE89K/uIfRdfX95edV4/t12CIa sP2JmSGhrN1DGnLZb91GGZ00I7JAfl6PqjHm0U4= X-Google-Smtp-Source: ABdhPJzJtXBOd/bkLvjoZVjkzFvN10f5OeSXZpomG0JnEZ7IVERbFfyYnVyGJHLRJgvSTf9gmNwMebqJIWhMnaSW5Pc= X-Received: by 2002:ac8:37e6:: with SMTP id e35mr307742qtc.310.1589902678273; Tue, 19 May 2020 08:37:58 -0700 (PDT) MIME-Version: 1.0 References: <202005191534.04JFYlSQ006759@gndrsh.dnsmgr.net> In-Reply-To: <202005191534.04JFYlSQ006759@gndrsh.dnsmgr.net> From: Kyle Evans Date: Tue, 19 May 2020 10:37:45 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: svn commit: r361238 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs To: "Rodney W. Grimes" Cc: src-committers , svn-src-all , svn-src-head Content-Type: text/plain; charset="UTF-8" X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 May 2020 15:37:59 -0000 On Tue, May 19, 2020 at 10:34 AM Rodney W. Grimes wrote: > > > On Tue, May 19, 2020 at 10:27 AM Rodney W. Grimes > > wrote: > > > > > > > On Tue, May 19, 2020 at 10:23 AM Rodney W. Grimes > > > > wrote: > > > > > > > > > > > Author: kevans > > > > > > Date: Tue May 19 02:41:05 2020 > > > > > > New Revision: 361238 > > > > > > URL: https://svnweb.freebsd.org/changeset/base/361238 > > > > > > > > > > > > Log: > > > > > > zfs: reject read(2) of a dirfd with EISDIR > > > > > > > > > > > > This is independent of the recently-discussed global change, which is still > > > > > > in review/discussion stage. > > > > > > > > > > > > This is effectively a measure for consistency in the ZFS world, where > > > > > > FreeBSD was the only platform (as far as I could find) that allowed this. > > > > > > What ZFS exposes is decidedly not useful for any real purposes, to > > > > > > paraphrase (hopefully faithfully) jhb's findings when exploring this: > > > > > > > > > > > > The size of a directory in ZFS is the number of directory entries within. > > > > > > When reading a directory, you would instead get the leading part of its raw > > > > > > contents; the amount you get being dictated by the "size," i.e. number of > > > > > > directory entries. There's decidedly (luckily) no stack disclosure happening > > > > > > here, though the behavior is bizarre and almost certainly a historical > > > > > > accident. > > > > > > > > > > > > This change has already been upstreamed to OpenZFS. > > > > > > > > > > Until the grep -d skip issue is addressed I object to this change as > > > > > it is going to cause people who do grep with wildcards to see lots > > > > > of errors that before where pretty much either silent (no match occured) > > > > > or spit out a "binary file foo matches." > > > > > > > > > > > > > That seems preferable to grepping random bytes that don't particularly > > > > contain any strings? They'd never see "binary file foo matches" in > > > > this case. > > > > > > The difference is you rarely get a hit, and now your gauranteed to > > > get a hit on every single directory making grep * very noisy, where > > > it was often silent or nearly silent before. > > > > > > > As you noted in the review for the larger change, -d skip is a good > > option for the people that don't like this. It probably makes sense as > > a default, but then we'd be diverging from the other popular grep that > > defaults to -d read and spews out EISDIR more often than not. > > Yet another thing I hate about Linux, thank you for adding it to FreeBSD :-) > > > > > > > > > This isn't exactly divergent from the behavior they'd see with ZFS > > > > anywhere else. > > > > > > It is extremly divergent from 42 years of behavior. > > > > > > > I don't think ZFS has been implemented on FreeBSD for 42 years, and I > > don't find this grep argument compelling enough to restore peoples' > > ability to read the raw znode of a directory. > > The EISDIR behavior is what your changing, independent of file system(s) > you have done so far. The fact the behavior is now different between > UFS and ZFS is sic, IMHO. EISDIR in read(2) denotes that a filesystem does not support reading a directory, this isn't a new kind of error. In particular, ZFS traditionally does NOT support reading a directory like this. The behavior between UFS and ZFS should have always been different, this is correction of a historical *accident*.