I just realised that this change avoids a more problematic issue. The loss of files on case insensitive file systems supporting hardlinks. Consider hfs...
$ truncate -s1G hfs.img $ mkfs.hfsplus hfs.img $ mkdir hfs $ sudo mount hfs.img hfs $ sudo su # cd hfs # touch foo # ln foo blah # mv foo Foo # foo is removed! # ls -l -rw-r--r--. 1 root root 0 Nov 22 02:42 blah In the attached patch I've added a test case, removed an old test case that pondered the issue in 5.0.91?, updated NEWS and mentioned the issue in copy.c cheers, Pádraig.
From a78819af2873ea7b104366bf72af7c3e5b30782b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]> Date: Sat, 22 Nov 2014 03:41:55 +0000 Subject: [PATCH] tests: add a case verifying mv on case insensitive file systems * NEWS: Update the recent entry to also mention the avoidance of incorrectly unlinking a multi-hardlinked "source" file when presented with source and dest that only differ in case. * src/copy.c (same_file_ok): Mention the case issue with same_name(). * tests/mv/hardlink-case.sh: Test the issue on HFS+. * tests/local.mk: Reference the new test case. * tests/mv/vfat: Remove an old related but unused test case. --- NEWS | 9 ++++--- src/copy.c | 1 + tests/local.mk | 1 + tests/mv/hardlink-case.sh | 37 +++++++++++++++++++++++++++ tests/mv/vfat | 64 ----------------------------------------------- 5 files changed, 44 insertions(+), 68 deletions(-) create mode 100755 tests/mv/hardlink-case.sh delete mode 100644 tests/mv/vfat diff --git a/NEWS b/NEWS index 6a84c48..5d3bc58 100644 --- a/NEWS +++ b/NEWS @@ -32,10 +32,11 @@ GNU coreutils NEWS -*- outline -*- ** Changes in behavior - mv no longer supports moving a file to a hardlink, as currently that - is only supported through unlinking the source file. That's racy - in the presence of multiple mv instances, which could result in both - hardlinks being deleted. This feature was added in coreutils-5.0.1. + mv no longer supports moving a file to a hardlink, instead issuing an error. + The implementation was susceptible to races in the presence of multiple mv + instances, which could result in both hardlinks being deleted. Also on case + insensitive file systems like HFS, mv would just remove a hardlinked 'file' + if called like `mv file File`. The feature was added in coreutils-5.0.1. ** Improvements diff --git a/src/copy.c b/src/copy.c index 01cee32..f316f05 100644 --- a/src/copy.c +++ b/src/copy.c @@ -1526,6 +1526,7 @@ same_file_ok (char const *src_name, struct stat const *src_sb, return true; } + /* FIXME: What about case insensitive file systems ? */ return ! same_name (src_name, dst_name); } diff --git a/tests/local.mk b/tests/local.mk index 22e8b86..653c984 100644 --- a/tests/local.mk +++ b/tests/local.mk @@ -127,6 +127,7 @@ all_root_tests = \ tests/misc/truncate-owned-by-other.sh \ tests/mkdir/writable-under-readonly.sh \ tests/mkdir/smack-root.sh \ + tests/mv/hardlink-case.sh \ tests/mv/sticky-to-xpart.sh \ tests/rm/fail-2eperm.sh \ tests/rm/no-give-up.sh \ diff --git a/tests/mv/hardlink-case.sh b/tests/mv/hardlink-case.sh new file mode 100755 index 0000000..5ab8c95 --- /dev/null +++ b/tests/mv/hardlink-case.sh @@ -0,0 +1,37 @@ +#!/bin/sh +# Ensure multi-hardlinked files are not lost on case insensitive file systems + +# Copyright (C) 2014 Free Software Foundation, Inc. + +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src +print_ver_ mv +require_root_ + +cwd=$(pwd) +cleanup_() { cd /; umount "$cwd/mnt"; } + +truncate -s100M hfs.img || framework_failure_ +mkfs -t hfsplus hfs.img || skip_ 'failed to create hfs file system' +mkdir mnt || framework_failure_ +mount hfs.img mnt || skip_ 'failed to mount hfs file system' + +cd mnt +touch foo +ln foo whatever +mv foo Foo && fail=1 +test -r foo || fail=1 + +Exit $fail diff --git a/tests/mv/vfat b/tests/mv/vfat deleted file mode 100644 index cd2f8b4..0000000 --- a/tests/mv/vfat +++ /dev/null @@ -1,64 +0,0 @@ -#!/bin/sh -# This is just for the record. -# This test is not run. - -# Copyright (C) 2003-2014 Free Software Foundation, Inc. - -# This program is free software: you can redistribute it and/or modify -# it under the terms of the GNU General Public License as published by -# the Free Software Foundation, either version 3 of the License, or -# (at your option) any later version. - -# This program is distributed in the hope that it will be useful, -# but WITHOUT ANY WARRANTY; without even the implied warranty of -# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -# GNU General Public License for more details. - -# You should have received a copy of the GNU General Public License -# along with this program. If not, see <http://www.gnu.org/licenses/>. - -exit 0 - -cat <<\EOF - -Prior to 5.0.91, ... - -The problem: - On a VFAT file system with coreutils-5.0.90, 'mv FOO foo' removes the - sole copy of the file named by both the source and destination arguments. - -Demonstrate the problem, as root: - -cd /tmp \ - && dd if=/dev/zero of=1 bs=8192 count=50 \ - && mkdir mnt && mkfs -t vfat 1 \ - && mount -oloop 1 mnt && cd mnt \ - && printf something important > foo \ - && mv foo FOO -test -f FOO && echo PASS-1 || echo FAIL-1 -ln foo bar -mv foo FOO -test -f FOO && echo PASS-2 || echo FAIL-2 - -And in case you actually do the above, you can do this to clean up: - - cd /tmp && umount /tmp/mnt && rm -r 1 mnt - -Hey! Can't create hard links on vfat. -The above 'ln' evokes an 'operation not permitted' failure. - -This demonstrates the same thing with file system type 'umsdos' -No hard links: - -cd /tmp \ - && dd if=/dev/zero of=1 bs=8192 count=50 \ - && mkdir mnt && mkfs -t msdos 1 \ - && mount -t umsdos -oloop 1 mnt && cd mnt \ - && printf something important > foo \ - && mv foo FOO -test -f FOO && echo PASS-1 || echo FAIL-1 -ln foo bar -mv foo FOO -test -f FOO && echo PASS-2 || echo FAIL-2 - -EOF -- 2.1.0
