On Fri, Oct 16, 2020 at 12:43:18PM +0200, mwilck@xxxxxxxx wrote:
> From: Martin Wilck <mwilck@xxxxxxxx>
>
> As one step towards bundling all possibly racy libdm init calls into a single
> function, split the code for determining and checking versions of
> libdm and kernel components. Provide a generic helper
> libmp_get_version() that makes sure the versions are "lazily" initialized.
>
> External callers may use dm_prereq(), like before.
> Minor API change: dm_prereq() does not nullify the argument any more
> if an error is encountered.
>
> Remove the conf->version field, which isn't needed any more after this
> change. This makes it necessary to fixup the hwtable test. Also, it
> represents an incompatible ABI change as offsets in "struct config" are
> changed, and two symbols removed. Bump the ABI major version to 2.
>
Reviewed-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> ---
> libmultipath/config.h | 1 -
> libmultipath/devmapper.c | 160 ++++++++++++++++++++----------
> libmultipath/devmapper.h | 11 +-
> libmultipath/libmultipath.version | 5 +-
> libmultipath/propsel.c | 10 +-
> multipathd/dmevents.c | 2 +-
> multipathd/main.c | 1 -
> tests/Makefile | 2 +-
> tests/hwtable.c | 3 -
> tests/test-lib.c | 13 +++
> 10 files changed, 141 insertions(+), 67 deletions(-)
>
> diff --git a/libmultipath/config.h b/libmultipath/config.h
> index 290aea5..7af1984 100644
> --- a/libmultipath/config.h
> +++ b/libmultipath/config.h
> @@ -192,7 +192,6 @@ struct config {
> int find_multipaths_timeout;
> int marginal_pathgroups;
> int skip_delegate;
> - unsigned int version[3];
> unsigned int sequence_nr;
>
> char * multipath_dir;
> diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> index 7394796..08aa09f 100644
> --- a/libmultipath/devmapper.c
> +++ b/libmultipath/devmapper.c
> @@ -26,6 +26,7 @@
> #include "sysfs.h"
> #include "config.h"
> #include "wwids.h"
> +#include "version.h"
>
> #include "log_pthread.h"
> #include <sys/types.h>
> @@ -34,7 +35,13 @@
> #define MAX_WAIT 5
> #define LOOPS_PER_SEC 5
>
> +#define INVALID_VERSION ~0U
> +static unsigned int dm_library_version[3] = { INVALID_VERSION, };
> +static unsigned int dm_kernel_version[3] = { INVALID_VERSION, };
> +static unsigned int dm_mpath_target_version[3] = { INVALID_VERSION, };
> +
> static pthread_once_t dm_initialized = PTHREAD_ONCE_INIT;
> +static pthread_once_t versions_initialized = PTHREAD_ONCE_INIT;
>
> static int dm_conf_verbosity;
>
> @@ -102,7 +109,7 @@ dm_write_log (int level, const char *file, int line, const char *f, ...)
> return;
> }
>
> -void dm_init(int v)
> +static void dm_init(int v)
> {
> /*
> * This maps libdm's standard loglevel _LOG_WARN (= 4), which is rather
> @@ -112,59 +119,66 @@ void dm_init(int v)
> dm_log_init(&dm_write_log);
> }
>
> +static void init_dm_library_version(void)
> +{
> + char version[64];
> + unsigned int v[3];
> +
> + dm_get_library_version(version, sizeof(version));
> + if (sscanf(version, "%u.%u.%u ", &v[0], &v[1], &v[2]) != 3) {
> + condlog(0, "invalid libdevmapper version %s", version);
> + return;
> + }
> + memcpy(dm_library_version, v, sizeof(dm_library_version));
> + condlog(3, "libdevmapper version %u.%.2u.%.2u",
> + dm_library_version[0], dm_library_version[1],
> + dm_library_version[2]);
> +}
> +
> static int
> dm_lib_prereq (void)
> {
> - char version[64];
> - int v[3];
> +
> #if defined(LIBDM_API_HOLD_CONTROL)
> - int minv[3] = {1, 2, 111};
> + unsigned int minv[3] = {1, 2, 111};
> #elif defined(LIBDM_API_DEFERRED)
> - int minv[3] = {1, 2, 89};
> + unsigned int minv[3] = {1, 2, 89};
> #elif defined(DM_SUBSYSTEM_UDEV_FLAG0)
> - int minv[3] = {1, 2, 82};
> + unsigned int minv[3] = {1, 2, 82};
> #elif defined(LIBDM_API_COOKIE)
> - int minv[3] = {1, 2, 38};
> + unsigned int minv[3] = {1, 2, 38};
> #else
> - int minv[3] = {1, 2, 8};
> + unsigned int minv[3] = {1, 2, 8};
> #endif
>
> - dm_get_library_version(version, sizeof(version));
> - condlog(3, "libdevmapper version %s", version);
> - if (sscanf(version, "%d.%d.%d ", &v[0], &v[1], &v[2]) != 3) {
> - condlog(0, "invalid libdevmapper version %s", version);
> - return 1;
> - }
> -
> - if VERSION_GE(v, minv)
> + if (VERSION_GE(dm_library_version, minv))
> return 0;
> - condlog(0, "libdevmapper version must be >= %d.%.2d.%.2d",
> + condlog(0, "libdevmapper version must be >= %u.%.2u.%.2u",
> minv[0], minv[1], minv[2]);
> return 1;
> }
>
> -int
> -dm_drv_version(unsigned int *v)
> +static void init_dm_drv_version(void)
> {
> char buff[64];
> -
> - v[0] = 0;
> - v[1] = 0;
> - v[2] = 0;
> + unsigned int v[3];
>
> if (!dm_driver_version(buff, sizeof(buff))) {
> condlog(0, "cannot get kernel dm version");
> - return 1;
> + return;
> }
> if (sscanf(buff, "%u.%u.%u ", &v[0], &v[1], &v[2]) != 3) {
> condlog(0, "invalid kernel dm version '%s'", buff);
> - return 1;
> + return;
> }
> - return 0;
> + memcpy(dm_kernel_version, v, sizeof(dm_library_version));
> + condlog(3, "kernel device mapper v%u.%u.%u",
> + dm_kernel_version[0],
> + dm_kernel_version[1],
> + dm_kernel_version[2]);
> }
>
> -int
> -dm_tgt_version (unsigned int * version, char * str)
> +static int dm_tgt_version (unsigned int *version, char *str)
> {
> int r = 2;
> struct dm_task *dmt;
> @@ -172,10 +186,11 @@ dm_tgt_version (unsigned int * version, char * str)
> struct dm_versions *last_target;
> unsigned int *v;
>
> - version[0] = 0;
> - version[1] = 0;
> - version[2] = 0;
> -
> + /*
> + * We have to call dm_task_create() and not libmp_dm_task_create()
> + * here to avoid a recursive invocation of
> + * pthread_once(&dm_initialized), which would cause a deadlock.
> + */
> if (!(dmt = dm_task_create(DM_DEVICE_LIST_VERSIONS)))
> return 1;
>
> @@ -211,26 +226,25 @@ out:
> return r;
> }
>
> -static int
> -dm_tgt_prereq (unsigned int *ver)
> +static void init_dm_mpath_version(void)
> {
> - unsigned int minv[3] = {1, 0, 3};
> - unsigned int version[3] = {0, 0, 0};
> - unsigned int * v = version;
> -
> - if (dm_tgt_version(v, TGT_MPATH)) {
> - /* in doubt return not capable */
> - return 1;
> - }
> + if (!dm_tgt_version(dm_mpath_target_version, TGT_MPATH))
> + condlog(3, "DM multipath kernel driver v%u.%u.%u",
> + dm_mpath_target_version[0],
> + dm_mpath_target_version[1],
> + dm_mpath_target_version[2]);
> +}
>
> - /* test request based multipath capability */
> - condlog(3, "DM multipath kernel driver v%u.%u.%u",
> - v[0], v[1], v[2]);
> +static int dm_tgt_prereq (unsigned int *ver)
> +{
> + unsigned int minv[3] = {1, 0, 3};
>
> - if (VERSION_GE(v, minv)) {
> - ver[0] = v[0];
> - ver[1] = v[1];
> - ver[2] = v[2];
> + if (VERSION_GE(dm_mpath_target_version, minv)) {
> + if (ver) {
> + ver[0] = dm_mpath_target_version[0];
> + ver[1] = dm_mpath_target_version[1];
> + ver[2] = dm_mpath_target_version[2];
> + }
> return 0;
> }
>
> @@ -239,13 +253,60 @@ dm_tgt_prereq (unsigned int *ver)
> return 1;
> }
>
> +static void _init_versions(void)
> +{
> + dlog(logsink, 3, VERSION_STRING);
> + init_dm_library_version();
> + init_dm_drv_version();
> + init_dm_mpath_version();
> +}
> +
> +static int init_versions(void) {
> + pthread_once(&versions_initialized, _init_versions);
> + return (dm_library_version[0] == INVALID_VERSION ||
> + dm_kernel_version[0] == INVALID_VERSION ||
> + dm_mpath_target_version[0] == INVALID_VERSION);
> +}
> +
> int dm_prereq(unsigned int *v)
> {
> + if (init_versions())
> + return 1;
> if (dm_lib_prereq())
> return 1;
> return dm_tgt_prereq(v);
> }
>
> +int libmp_get_version(int which, unsigned int version[3])
> +{
> + unsigned int *src_version;
> +
> + init_versions();
> + switch (which) {
> + case DM_LIBRARY_VERSION:
> + src_version = dm_library_version;
> + break;
> + case DM_KERNEL_VERSION:
> + src_version = dm_kernel_version;
> + break;
> + case DM_MPATH_TARGET_VERSION:
> + src_version = dm_mpath_target_version;
> + break;
> + case MULTIPATH_VERSION:
> + version[0] = (VERSION_CODE >> 16) & 0xff;
> + version[1] = (VERSION_CODE >> 8) & 0xff;
> + version[2] = VERSION_CODE & 0xff;
> + return 0;
> + default:
> + condlog(0, "%s: invalid value for 'which'", __func__);
> + return 1;
> + }
> + if (src_version[0] == INVALID_VERSION)
> + return 1;
> + memcpy(version, src_version, 3 * sizeof(*version));
> + return 0;
> +}
> +
> static int libmp_dm_udev_sync = 0;
>
> void libmp_udev_set_sync_support(int on)
> @@ -263,7 +324,6 @@ static void libmp_dm_init(void)
> exit(1);
> conf = get_multipath_config();
> verbosity = conf->verbosity;
> - memcpy(conf->version, version, sizeof(version));
> put_multipath_config(conf);
> dm_init(verbosity);
> #ifdef LIBDM_API_HOLD_CONTROL
> diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
> index f568ab5..c8b37e1 100644
> --- a/libmultipath/devmapper.h
> +++ b/libmultipath/devmapper.h
> @@ -33,13 +33,10 @@ enum {
> DMP_NOT_FOUND,
> };
>
> -void dm_init(int verbosity);
> int dm_prereq(unsigned int *v);
> void skip_libmp_dm_init(void);
> void libmp_udev_set_sync_support(int on);
> struct dm_task *libmp_dm_task_create(int task);
> -int dm_drv_version (unsigned int * version);
> -int dm_tgt_version (unsigned int * version, char * str);
> int dm_simplecmd_flush (int, const char *, uint16_t);
> int dm_simplecmd_noflush (int, const char *, uint16_t);
> int dm_addmap_create (struct multipath *mpp, char *params);
> @@ -85,6 +82,14 @@ struct multipath *dm_get_multipath(const char *name);
> ((v[0] == minv[0]) && (v[1] == minv[1]) && (v[2] >= minv[2])) \
> )
>
> +enum {
> + DM_LIBRARY_VERSION,
> + DM_KERNEL_VERSION,
> + DM_MPATH_TARGET_VERSION,
> + MULTIPATH_VERSION
> +};
> +int libmp_get_version(int which, unsigned int version[3]);
> +
> #define dm_log_error(lvl, cmd, dmt) \
> condlog(lvl, "%s: libdm task=%d error: %s", __func__, \
> cmd, strerror(dm_task_get_errno(dmt))) \
> diff --git a/libmultipath/libmultipath.version b/libmultipath/libmultipath.version
> index a6bf821..ab5bb0a 100644
> --- a/libmultipath/libmultipath.version
> +++ b/libmultipath/libmultipath.version
> @@ -31,7 +31,7 @@
> * The new version inherits the previous ones.
> */
>
> -LIBMULTIPATH_1.0.0 {
> +LIBMULTIPATH_2.0.0 {
> global:
> /* symbols referenced by multipath and multipathd */
> add_foreign;
> @@ -65,7 +65,6 @@ global:
> disassemble_status;
> dlog;
> dm_cancel_deferred_remove;
> - dm_drv_version;
> dm_enablegroup;
> dm_fail_path;
> _dm_flush_map;
> @@ -87,7 +86,6 @@ global:
> dm_reinstate_path;
> dm_simplecmd_noflush;
> dm_switchgroup;
> - dm_tgt_version;
> domap;
> ensure_directories_exist;
> extract_hwe_from_path;
> @@ -128,6 +126,7 @@ global:
> is_path_valid;
> is_quote;
> libmp_dm_task_create;
> + libmp_get_version;
> libmp_udev_set_sync_support;
> load_config;
> log_thread_reset;
> diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
> index 4020134..3f2c2cf 100644
> --- a/libmultipath/propsel.c
> +++ b/libmultipath/propsel.c
> @@ -735,9 +735,10 @@ out:
>
> int select_minio(struct config *conf, struct multipath *mp)
> {
> - unsigned int minv_dmrq[3] = {1, 1, 0};
> + unsigned int minv_dmrq[3] = {1, 1, 0}, version[3];
>
> - if (VERSION_GE(conf->version, minv_dmrq))
> + if (!libmp_get_version(DM_MPATH_TARGET_VERSION, version)
> + && VERSION_GE(version, minv_dmrq))
> return select_minio_rq(conf, mp);
> else
> return select_minio_bio(conf, mp);
> @@ -820,9 +821,10 @@ out:
> int select_retain_hwhandler(struct config *conf, struct multipath *mp)
> {
> const char *origin;
> - unsigned int minv_dm_retain[3] = {1, 5, 0};
> + unsigned int minv_dm_retain[3] = {1, 5, 0}, version[3];
>
> - if (!VERSION_GE(conf->version, minv_dm_retain)) {
> + if (!libmp_get_version(DM_MPATH_TARGET_VERSION, version) &&
> + !VERSION_GE(version, minv_dm_retain)) {
> mp->retain_hwhandler = RETAIN_HWHANDLER_OFF;
> origin = "(setting: WARNING, requires kernel dm-mpath version >= 1.5.0)";
> goto out;
> diff --git a/multipathd/dmevents.c b/multipathd/dmevents.c
> index 5f2d210..fc97c8a 100644
> --- a/multipathd/dmevents.c
> +++ b/multipathd/dmevents.c
> @@ -60,7 +60,7 @@ int dmevent_poll_supported(void)
> {
> unsigned int v[3];
>
> - if (dm_drv_version(v))
> + if (libmp_get_version(DM_KERNEL_VERSION, v))
> return 0;
>
> if (VERSION_GE(v, DM_VERSION_FOR_ARM_POLL))
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 5cc3435..00b66ba 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -2709,7 +2709,6 @@ reconfigure (struct vectors * vecs)
> /* Re-read any timezone changes */
> tzset();
>
> - dm_tgt_version(conf->version, TGT_MPATH);
> if (verbosity)
> conf->verbosity = verbosity;
> if (bindings_read_only)
> diff --git a/tests/Makefile b/tests/Makefile
> index f6ef16a..7a73869 100644
> --- a/tests/Makefile
> +++ b/tests/Makefile
> @@ -42,7 +42,7 @@ endif
> dmevents-test_LIBDEPS = -lpthread -ldevmapper -lurcu
> hwtable-test_TESTDEPS := test-lib.o
> hwtable-test_OBJDEPS := ../libmultipath/discovery.o ../libmultipath/blacklist.o \
> - ../libmultipath/structs.o
> + ../libmultipath/structs.o ../libmultipath/propsel.o
> hwtable-test_LIBDEPS := -ludev -lpthread -ldl
> blacklist-test_TESTDEPS := test-log.o
> blacklist-test_OBJDEPS := ../libmultipath/blacklist.o
> diff --git a/tests/hwtable.c b/tests/hwtable.c
> index 12660da..57f832b 100644
> --- a/tests/hwtable.c
> +++ b/tests/hwtable.c
> @@ -30,8 +30,6 @@
> #define N_CONF_FILES 2
>
> static const char tmplate[] = "/tmp/hwtable-XXXXXX";
> -/* pretend new dm, use minio_rq */
> -static const unsigned int dm_tgt_version[3] = { 1, 1, 1 };
>
> struct key_value {
> const char *key;
> @@ -360,7 +358,6 @@ static void write_device(FILE *ff, int nkv, const struct key_value *kv)
> assert_ptr_not_equal(__cf, NULL); \
> assert_ptr_not_equal(__cf->hwtable, NULL); \
> __cf->verbosity = VERBOSITY; \
> - memcpy(&__cf->version, dm_tgt_version, sizeof(__cf->version)); \
> __cf; })
>
> #define FREE_CONFIG(conf) do { \
> diff --git a/tests/test-lib.c b/tests/test-lib.c
> index b7c09cc..e7663f9 100644
> --- a/tests/test-lib.c
> +++ b/tests/test-lib.c
> @@ -56,6 +56,15 @@ int __wrap_execute_program(char *path, char *value, int len)
> return 0;
> }
>
> +int __wrap_libmp_get_version(int which, unsigned int version[3])
> +{
> + unsigned int *vers = mock_ptr_type(unsigned int *);
> +
> + condlog(4, "%s: %d", __func__, which);
> + memcpy(version, vers, 3 * sizeof(unsigned int));
> + return 0;
> +}
> +
> struct udev_list_entry
> *__wrap_udev_device_get_properties_list_entry(struct udev_device *ud)
> {
> @@ -339,6 +348,8 @@ struct multipath *__mock_multipath(struct vectors *vecs, struct path *pp)
> struct multipath *mp;
> struct config *conf;
> struct mocked_path mop;
> + /* pretend new dm, use minio_rq, */
> + static const unsigned int fake_dm_tgt_version[3] = { 1, 1, 1 };
>
> mocked_path_from_path(&mop, pp);
> /* pathinfo() call in adopt_paths */
> @@ -351,7 +362,9 @@ struct multipath *__mock_multipath(struct vectors *vecs, struct path *pp)
> conf = get_multipath_config();
> select_pgpolicy(conf, mp);
> select_no_path_retry(conf, mp);
> + will_return(__wrap_libmp_get_version, fake_dm_tgt_version);
> select_retain_hwhandler(conf, mp);
> + will_return(__wrap_libmp_get_version, fake_dm_tgt_version);
> select_minio(conf, mp);
> put_multipath_config(conf);
>
> --
> 2.28.0
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