[dm-devel] [PATCH] libmultipath: lazy device-mapper initialization
Martin Wilck
mwilck at suse.com
Tue Jun 6 19:33:11 UTC 2017
The multipath command fails early if libdevmapper and/or the
dm_multipath driver are not found. But some multipath operations
don't require device mapper, notably the path checking operations
called from udev rules during early boot.
This patch delays dm initialization until the first device-mapper
call, allowing such operations to succeed even if the dm_multipath
driver is not loaded yet.
This fixes the following problem: during system boot, the dm_multipath
driver is usually loaded via "ExecStartPre" from the multipathd service
file. But with commit d7188fcd, this service is started only after
udev settle and thus the modules are loaded too late for udev
rule processing, causing "multipath" invocations from udev rules to fail
and paths to be wrongly classified as non-multipath.
Fixes: d7188fcd "multipathd: start daemon after udev trigger"
Signed-off-by: Martin Wilck <mwilck at suse.com>
---
libmultipath/devmapper.c | 79 ++++++++++++++++++++++++++++++++++--------------
libmultipath/devmapper.h | 4 ++-
libmultipath/waiter.c | 2 +-
multipath/main.c | 8 ++---
multipathd/main.c | 4 +--
5 files changed, 63 insertions(+), 34 deletions(-)
diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 69b634bf..4319b381 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -21,6 +21,7 @@
#include "memory.h"
#include "devmapper.h"
#include "sysfs.h"
+#include "config.h"
#include "log_pthread.h"
#include <sys/types.h>
@@ -178,7 +179,7 @@ out:
}
static int
-dm_drv_prereq (void)
+dm_drv_prereq (unsigned int *ver)
{
unsigned int minv[3] = {1, 0, 3};
unsigned int version[3] = {0, 0, 0};
@@ -193,19 +194,51 @@ dm_drv_prereq (void)
condlog(3, "DM multipath kernel driver v%u.%u.%u",
v[0], v[1], v[2]);
- if VERSION_GE(v, minv)
+ if (VERSION_GE(v, minv)) {
+ ver[0] = v[0];
+ ver[1] = v[1];
+ ver[2] = v[2];
return 0;
+ }
condlog(0, "DM multipath kernel driver must be >= v%u.%u.%u",
minv[0], minv[1], minv[2]);
return 1;
}
-int dm_prereq(void)
+static int dm_prereq(unsigned int *v)
{
if (dm_lib_prereq())
return 1;
- return dm_drv_prereq();
+ return dm_drv_prereq(v);
+}
+
+static int libmp_dm_udev_sync = 0;
+
+void libmp_udev_set_sync_support(int on)
+{
+ libmp_dm_udev_sync = !!on;
+}
+
+void libmp_dm_init(void)
+{
+ struct config *conf;
+
+ conf = get_multipath_config();
+ dm_init(conf->verbosity);
+ if (dm_prereq(conf->version))
+ exit(1);
+ put_multipath_config(conf);
+ dm_udev_set_sync_support(libmp_dm_udev_sync);
+}
+
+struct dm_task*
+libmp_dm_task_create(int task)
+{
+ static pthread_once_t dm_initialized = PTHREAD_ONCE_INIT;
+
+ pthread_once(&dm_initialized, libmp_dm_init);
+ return dm_task_create(task);
}
#define do_deferred(x) ((x) == DEFERRED_REMOVE_ON || (x) == DEFERRED_REMOVE_IN_PROGRESS)
@@ -219,7 +252,7 @@ dm_simplecmd (int task, const char *name, int no_flush, int need_sync, uint16_t
uint32_t cookie = 0;
struct dm_task *dmt;
- if (!(dmt = dm_task_create (task)))
+ if (!(dmt = libmp_dm_task_create (task)))
return 0;
if (!dm_task_set_name (dmt, name))
@@ -274,7 +307,7 @@ dm_addmap (int task, const char *target, struct multipath *mpp,
uint32_t cookie = 0;
uint16_t udev_flags = DM_UDEV_DISABLE_LIBRARY_FALLBACK | ((skip_kpartx == SKIP_KPARTX_ON)? MPATH_UDEV_NO_KPARTX_FLAG : 0);
- if (!(dmt = dm_task_create (task)))
+ if (!(dmt = libmp_dm_task_create (task)))
return 0;
if (!dm_task_set_name (dmt, mpp->alias))
@@ -411,7 +444,7 @@ do_get_info(const char *name, struct dm_info *info)
int r = -1;
struct dm_task *dmt;
- if (!(dmt = dm_task_create(DM_DEVICE_INFO)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_INFO)))
return r;
if (!dm_task_set_name(dmt, name))
@@ -449,7 +482,7 @@ int dm_get_map(const char *name, unsigned long long *size, char *outparams)
char *target_type = NULL;
char *params = NULL;
- if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))
return 1;
if (!dm_task_set_name(dmt, name))
@@ -485,7 +518,7 @@ dm_get_prefixed_uuid(const char *name, char *uuid)
const char *uuidtmp;
int r = 1;
- dmt = dm_task_create(DM_DEVICE_INFO);
+ dmt = libmp_dm_task_create(DM_DEVICE_INFO);
if (!dmt)
return 1;
@@ -548,7 +581,7 @@ int dm_get_status(char *name, char *outstatus)
char *target_type = NULL;
char *status = NULL;
- if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_STATUS)))
return 1;
if (!dm_task_set_name(dmt, name))
@@ -591,7 +624,7 @@ int dm_type(const char *name, char *type)
char *target_type = NULL;
char *params;
- if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))
return 0;
if (!dm_task_set_name(dmt, name))
@@ -627,7 +660,7 @@ int dm_is_mpath(const char *name)
char *params;
const char *uuid;
- if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))
return 0;
if (!dm_task_set_name(dmt, name))
@@ -679,7 +712,7 @@ dm_get_opencount (const char * mapname)
struct dm_task *dmt;
struct dm_info info;
- if (!(dmt = dm_task_create(DM_DEVICE_INFO)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_INFO)))
return 0;
if (!dm_task_set_name(dmt, mapname))
@@ -837,7 +870,7 @@ int dm_flush_maps (int retries)
struct dm_names *names;
unsigned next = 0;
- if (!(dmt = dm_task_create (DM_DEVICE_LIST)))
+ if (!(dmt = libmp_dm_task_create (DM_DEVICE_LIST)))
return 0;
dm_task_no_open_count(dmt);
@@ -868,7 +901,7 @@ dm_message(const char * mapname, char * message)
int r = 1;
struct dm_task *dmt;
- if (!(dmt = dm_task_create(DM_DEVICE_TARGET_MSG)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_TARGET_MSG)))
return 1;
if (!dm_task_set_name(dmt, mapname))
@@ -970,7 +1003,7 @@ dm_get_maps (vector mp)
if (!mp)
return 1;
- if (!(dmt = dm_task_create(DM_DEVICE_LIST)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_LIST)))
return 1;
dm_task_no_open_count(dmt);
@@ -1056,7 +1089,7 @@ dm_mapname(int major, int minor)
int r;
int loop = MAX_WAIT * LOOPS_PER_SEC;
- if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_STATUS)))
return NULL;
if (!dm_task_set_major(dmt, major) ||
@@ -1109,7 +1142,7 @@ do_foreach_partmaps (const char * mapname,
int r = 1;
char *p;
- if (!(dmt = dm_task_create(DM_DEVICE_LIST)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_LIST)))
return 1;
dm_task_no_open_count(dmt);
@@ -1333,7 +1366,7 @@ dm_rename (const char * old, char * new, char *delim, int skip_kpartx)
if (dm_rename_partmaps(old, new, delim))
return r;
- if (!(dmt = dm_task_create(DM_DEVICE_RENAME)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_RENAME)))
return r;
if (!dm_task_set_name(dmt, old))
@@ -1382,7 +1415,7 @@ int dm_reassign_table(const char *name, char *old, char *new)
char *buff;
void *next = NULL;
- if (!(dmt = dm_task_create(DM_DEVICE_TABLE)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_TABLE)))
return 0;
if (!dm_task_set_name(dmt, name))
@@ -1392,7 +1425,7 @@ int dm_reassign_table(const char *name, char *old, char *new)
if (!dm_task_run(dmt))
goto out;
- if (!(reload_dmt = dm_task_create(DM_DEVICE_RELOAD)))
+ if (!(reload_dmt = libmp_dm_task_create(DM_DEVICE_RELOAD)))
goto out;
if (!dm_task_set_name(reload_dmt, name))
goto out_reload;
@@ -1456,7 +1489,7 @@ int dm_reassign(const char *mapname)
return 1;
}
- if (!(dmt = dm_task_create(DM_DEVICE_DEPS))) {
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_DEPS))) {
condlog(3, "%s: couldn't make dm task", mapname);
return 0;
}
@@ -1514,7 +1547,7 @@ int dm_setgeometry(struct multipath *mpp)
return 1;
}
- if (!(dmt = dm_task_create(DM_DEVICE_SET_GEOMETRY)))
+ if (!(dmt = libmp_dm_task_create(DM_DEVICE_SET_GEOMETRY)))
return 0;
if (!dm_task_set_name(dmt, mpp->alias))
diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
index fa739bcc..99a554b5 100644
--- a/libmultipath/devmapper.h
+++ b/libmultipath/devmapper.h
@@ -25,7 +25,9 @@
#endif
void dm_init(int verbosity);
-int dm_prereq (void);
+void 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, char * str);
int dm_simplecmd_flush (int, const char *, uint16_t);
int dm_simplecmd_noflush (int, const char *, uint16_t);
diff --git a/libmultipath/waiter.c b/libmultipath/waiter.c
index 995ea1ad..cb9708b2 100644
--- a/libmultipath/waiter.c
+++ b/libmultipath/waiter.c
@@ -76,7 +76,7 @@ static int waiteventloop (struct event_thread *waiter)
if (!waiter->event_nr)
waiter->event_nr = dm_geteventnr(waiter->mapname);
- if (!(waiter->dmt = dm_task_create(DM_DEVICE_WAITEVENT))) {
+ if (!(waiter->dmt = libmp_dm_task_create(DM_DEVICE_WAITEVENT))) {
condlog(0, "%s: devmap event #%i dm_task_create error",
waiter->mapname, waiter->event_nr);
return 1;
diff --git a/multipath/main.c b/multipath/main.c
index 4174d43d..dede017e 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -634,12 +634,6 @@ main (int argc, char *argv[])
exit(1);
}
- dm_init(conf->verbosity);
- if (dm_prereq())
- exit(1);
- dm_drv_version(conf->version, TGT_MPATH);
- dm_udev_set_sync_support(1);
-
if (optind < argc) {
dev = MALLOC(FILE_NAME_SIZE);
@@ -670,6 +664,8 @@ main (int argc, char *argv[])
conf->max_fds, strerror(errno));
}
+ libmp_udev_set_sync_support(1);
+
if (init_checkers(conf->multipath_dir)) {
condlog(0, "failed to initialize checkers");
goto out;
diff --git a/multipathd/main.c b/multipathd/main.c
index 81c76cab..4be2c579 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -2408,8 +2408,6 @@ child (void * param)
conf->ignore_new_devs = ignore_new_devs;
uxsock_timeout = conf->uxsock_timeout;
rcu_assign_pointer(multipath_conf, conf);
- dm_init(conf->verbosity);
- dm_drv_version(conf->version, TGT_MPATH);
if (init_checkers(conf->multipath_dir)) {
condlog(0, "failed to initialize checkers");
goto failed;
@@ -2458,7 +2456,6 @@ child (void * param)
setscheduler();
set_oom_adj();
- dm_udev_set_sync_support(0);
#ifdef USE_SYSTEMD
envp = getenv("WATCHDOG_USEC");
if (envp && sscanf(envp, "%lu", &checkint) == 1) {
@@ -2700,6 +2697,7 @@ main (int argc, char *argv[])
pthread_cond_init_mono(&config_cond);
udev = udev_new();
+ libmp_udev_set_sync_support(0);
while ((arg = getopt(argc, argv, ":dsv:k::Bn")) != EOF ) {
switch(arg) {
--
2.13.0
More information about the dm-devel
mailing list