On Wed, Sep 16, 2020 at 05:37:09PM +0200, [email protected] wrote: > From: Martin Wilck <[email protected]> > > 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. > Note that retrieving the versions requires libdm calls, thus the > version initialization calls libdm initialization, which might call > version initialization recursively. But that's not an issue, as > the initialization is protected by pthread_once().
This is confusing me. dm_tgt_version will call DM_DEVICE_LIST_VERSIONS, but it doesn't call libmp_dm_task_create(), so I don't see the recursion possiblity. That's good because according to the man page: "If you specify a routine that directly or indirectly results in a recursive call to pthread_once(3) and that specifies the same routine argument, the recursive call can result in a deadlock." -Ben > 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. > > Cc: [email protected] > Cc: Zdenek Kabelac <[email protected]> > Signed-off-by: Martin Wilck <[email protected]> > --- > libmultipath/config.h | 1 - > libmultipath/devmapper.c | 155 ++++++++++++++++++++++++++------------- > libmultipath/devmapper.h | 11 ++- > libmultipath/propsel.c | 10 ++- > multipathd/dmevents.c | 2 +- > multipathd/main.c | 1 - > 6 files changed, 120 insertions(+), 60 deletions(-) > > diff --git a/libmultipath/config.h b/libmultipath/config.h > index 2bb7153..8e13ae9 100644 > --- a/libmultipath/config.h > +++ b/libmultipath/config.h > @@ -191,7 +191,6 @@ 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 cc2de1d..3694cc8 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 +186,6 @@ 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; > - > if (!(dmt = dm_task_create(DM_DEVICE_LIST_VERSIONS))) > return 1; > > @@ -211,26 +221,25 @@ 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; > - } > - > - /* test request based multipath capability */ > + dm_tgt_version(dm_mpath_target_version, TGT_MPATH); > condlog(3, "DM multipath kernel driver v%u.%u.%u", > - v[0], v[1], v[2]); > + dm_mpath_target_version[0], > + dm_mpath_target_version[1], > + dm_mpath_target_version[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 +248,60 @@ 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 +319,6 @@ 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/propsel.c b/libmultipath/propsel.c > index 7e6e0d6..781515e 100644 > --- a/libmultipath/propsel.c > +++ b/libmultipath/propsel.c > @@ -737,9 +737,10 @@ 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); > @@ -822,9 +823,10 @@ 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 affe706..53bacac 100644 > --- a/multipathd/main.c > +++ b/multipathd/main.c > @@ -2719,7 +2719,6 @@ 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) > -- > 2.28.0 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
