From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Benjamin Marzinski Date: Sat, 21 Mar 2020 23:49:59 -0500 Subject: [PATCH] libmutipath: don't close fd on dm_lib_release If dm_hold_control_open() isn't set, when dm_lib_release() is called, it will close the control fd. The control fd will get re-opened on the next dm_task_run() call, but if there is a dm_task_run() call already in progress in another thread, it can fail. Since many of the device-mapper callouts happen with the vecs lock held, this wasn't too noticeable, but there is code that calls dm_task_run() without the vecs lock held, notably the dmevent waiter code. Since, as Martin pointed out, dm_hold_control_open() hasn't always existed in libdevmapper, check if it's supported on compilation, and update the version requirements if so. Signed-off-by: Benjamin Marzinski --- libmultipath/Makefile | 4 ++++ libmultipath/devmapper.c | 7 ++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/libmultipath/Makefile b/libmultipath/Makefile index e5651e49..ad690a49 100644 --- a/libmultipath/Makefile +++ b/libmultipath/Makefile @@ -36,6 +36,10 @@ ifneq ($(call check_func,dm_task_deferred_remove,/usr/include/libdevmapper.h),0) CFLAGS += -DLIBDM_API_DEFERRED endif +ifneq ($(call check_func,dm_hold_control_dev,/usr/include/libdevmapper.h),0) + CFLAGS += -DLIBDM_API_HOLD_CONTROL +endif + OBJS = memory.o parser.o vector.o devmapper.o callout.o \ hwtable.o blacklist.o util.o dmparser.o config.o \ structs.o discovery.o propsel.o dict.o \ diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c index bed8ddc6..13a1cf53 100644 --- a/libmultipath/devmapper.c +++ b/libmultipath/devmapper.c @@ -108,7 +108,9 @@ dm_lib_prereq (void) { char version[64]; int v[3]; -#if defined(LIBDM_API_DEFERRED) +#if defined(LIBDM_API_HOLD_CONTROL) + int minv[3] = {1, 2, 111}; +#elif defined(LIBDM_API_DEFERRED) int minv[3] = {1, 2, 89}; #elif defined(DM_SUBSYSTEM_UDEV_FLAG0) int minv[3] = {1, 2, 82}; @@ -254,6 +256,9 @@ void libmp_dm_init(void) memcpy(conf->version, version, sizeof(version)); put_multipath_config(conf); dm_init(verbosity); +#ifdef LIBDM_API_HOLD_CONTROL + dm_hold_control_dev(1); +#endif dm_udev_set_sync_support(libmp_dm_udev_sync); } -- 2.17.2