From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:60439 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758166AbcEFT16 (ORCPT ); Fri, 6 May 2016 15:27:58 -0400 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id DBDB4ABF6 for ; Fri, 6 May 2016 19:27:56 +0000 (UTC) To: linux-btrfs From: Jeff Mahoney Subject: [PATCH] btrfs-progs: udev: add rules for dm devices Message-ID: <6ddc2c5c-42df-e7ca-daff-8848cbc3d9e9@suse.com> Date: Fri, 6 May 2016 15:27:54 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Systemd's btrfs rule runs btrfs dev ready on each device as it's discovered. The btrfs command is executed as a builtin command via an IMPORT{builtin} rule, which means it gets executed at rule evaluation time, not rule execution time. That means that the device mapper links haven't been setup yet and the only nodes that can be depended upon are /dev/dm-#. That we see /dev/mapper/name names in /proc/mounts is only because we replace the device name we have cached with the one passed in via mount. If we have a multi-device file system and the primary device is removed, the remaining devices will show /dev/dm-#. In addition, if the udev rule is executed again by someone generating a change event (e.g. partprobe), the names are also replaced by the /dev/dm-# names. This patch adds a new rule that adds a run rule that calls btrfs dev ready again using the device mapper links once they're created. --- 64-btrfs-dm.rules | 10 ++++++++++ Makefile.in | 7 +++++++ configure.ac | 2 ++ 3 files changed, 19 insertions(+) create mode 100644 64-btrfs-dm.rules diff --git a/64-btrfs-dm.rules b/64-btrfs-dm.rules new file mode 100644 index 0000000..bbe1c35 --- /dev/null +++ b/64-btrfs-dm.rules @@ -0,0 +1,10 @@ +SUBSYSTEM!="block", GOTO="btrfs_end" +KERNEL!="dm-[0-9]*", GOTO="btrfs_end" +ACTION!="add|change", GOTO="btrfs_end" +ENV{ID_FS_TYPE}!="btrfs", GOTO="btrfs_end" + +# Once the device mapper symlink is created, tell btrfs about it +# so we get the friendly name in /proc/mounts (and tools that read it) +ENV{DM_NAME}=="?*", TEST=="/dev/mapper/$env{DM_NAME}", RUN{builtin}+="btrfs ready /dev/mapper/$env{DM_NAME}" + +LABEL="btrfs_end" diff --git a/Makefile.in b/Makefile.in index 19697ff..d555f6a 100644 --- a/Makefile.in +++ b/Makefile.in @@ -83,11 +83,15 @@ libbtrfs_headers = send-stream.h send-utils.h send.h rbtree.h btrfs-list.h \ extent_io.h ioctl.h ctree.h btrfsck.h version.h TESTS = fsck-tests.sh convert-tests.sh +udev_rules = 64-btrfs-dm.rules + prefix ?= @prefix@ exec_prefix = @exec_prefix@ bindir = @bindir@ libdir ?= @libdir@ incdir = @includedir@/btrfs +udevdir = @UDEVDIR@ +udevruledir = ${udevdir}/rules.d ifeq ("$(origin V)", "command line") BUILD_VERBOSE = $(V) @@ -377,6 +381,9 @@ install: $(libs) $(progs_install) $(INSTALLDIRS) cp -a $(lib_links) $(DESTDIR)$(libdir) $(INSTALL) -m755 -d $(DESTDIR)$(incdir) $(INSTALL) -m644 $(headers) $(DESTDIR)$(incdir) +ifneq ($(udevdir), "") + $(INSTALL) -m644 $(udev_rules) $(DESTDIR)$(udevruledir) +endif install-static: $(progs_static) $(INSTALLDIRS) for p in $(progs_static) ; do \ diff --git a/configure.ac b/configure.ac index fc343ea..4af7474 100644 --- a/configure.ac +++ b/configure.ac @@ -124,6 +124,8 @@ PKG_STATIC(UUID_LIBS_STATIC, [uuid]) PKG_CHECK_MODULES(ZLIB, [zlib]) PKG_STATIC(ZLIB_LIBS_STATIC, [zlib]) +PKG_CHECK_VAR([UDEVDIR], [udev], [udevdir]) + dnl lzo library does not provide pkg-config, let use classic way AC_CHECK_LIB([lzo2], [lzo_version], [ LZO2_LIBS="-llzo2" -- 2.7.1 -- Jeff Mahoney SUSE Labs