libmultipath: Fixup 'DM_DEVICE_RELOAD' handling

libdevmapper has the 'quirk' that DM_DEVICE_CREATE is translated
internally into a create/load/resume sequence, and the associated
cookie will wait for the last 'resume' to complete.
However, DM_DEVICE_RELOAD has no such translation, so if there
is a cookie assigned to it the caller _cannot_ wait for it,
as the cookie will only ever be completed upon the next
DM_DEVICE_RESUME.
multipathd already has some provisions for that (but even there
the cookie handling is dodgy), but 'multipath -r' doesn't know
about this.
So to avoid any future irritations this patch updates the
dm_addmad_reload() call to handle the call to DM_DEVICE_RESUME
correctly and removes the special handling from domap().

Signed-off-by: Hannes Reinecke <hare@suse.de>

diff --git a/libmultipath/configure.c b/libmultipath/configure.c
index 708dae8..a4a2c44 100644 (file)
--- a/libmultipath/configure.c
+++ b/libmultipath/configure.c
@@ -625,16 +625,11 @@ domap (struct multipath * mpp, char * params)
                break;
 
        case ACT_RELOAD:
-               r = dm_addmap_reload(mpp, params);
-               if (r)
-                       r = dm_simplecmd_noflush(DM_DEVICE_RESUME, mpp->alias,
-                                                MPATH_UDEV_RELOAD_FLAG);
+               r = dm_addmap_reload(mpp, params, 0);
                break;
 
        case ACT_RESIZE:
-               r = dm_addmap_reload(mpp, params);
-               if (r)
-                       r = dm_simplecmd_flush(DM_DEVICE_RESUME, mpp->alias, 0);
+               r = dm_addmap_reload(mpp, params, 1);
                break;
 
        case ACT_RENAME:
@@ -643,13 +638,8 @@ domap (struct multipath * mpp, char * params)
 
        case ACT_FORCERENAME:
                r = dm_rename(mpp->alias_old, mpp->alias);
-               if (r) {
-                       r = dm_addmap_reload(mpp, params);
-                       if (r)
-                               r = dm_simplecmd_noflush(DM_DEVICE_RESUME,
-                                                        mpp->alias,
-                                                        MPATH_UDEV_RELOAD_FLAG);
-               }
+               if (r)
+                       r = dm_addmap_reload(mpp, params, 0);
                break;
 
        default:

diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 6983ab6..6d1a5d6 100644 (file)
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -312,7 +312,8 @@ dm_addmap (int task, const char *target, struct multipath *mpp,
        if (mpp->attribute_flags & (1 << ATTR_GID) &&
            !dm_task_set_gid(dmt, mpp->gid))
                goto freeout;
-       condlog(4, "%s: addmap [0 %llu %s %s]", mpp->alias, mpp->size,
+       condlog(4, "%s: %s [0 %llu %s %s]", mpp->alias,
+               task == DM_DEVICE_RELOAD ? "reload" : "addmap", mpp->size,
                target, params);
 
        dm_task_no_open_count(dmt);
@@ -371,12 +372,28 @@ dm_addmap_create (struct multipath *mpp, char * params) {
 #define ADDMAP_RO 1
 
 extern int
-dm_addmap_reload (struct multipath *mpp, char *params) {
-       if (dm_addmap(DM_DEVICE_RELOAD, TGT_MPATH, mpp, params, ADDMAP_RW))
-               return 1;
-       if (errno != EROFS)
-               return 0;
-       return dm_addmap(DM_DEVICE_RELOAD, TGT_MPATH, mpp, params, ADDMAP_RO);
+dm_addmap_reload (struct multipath *mpp, char *params, int flush)
+{
+       int r;
+       uint16_t udev_flags = flush ? 0 : MPATH_UDEV_RELOAD_FLAG;
+
+       /*
+        * DM_DEVICE_RELOAD cannot wait on a cookie, as
+        * the cookie will only ever be released after an
+        * DM_DEVICE_RESUME. So call DM_DEVICE_RESUME
+        * after each successful call to DM_DEVICE_RELOAD.
+        */
+       r = dm_addmap(DM_DEVICE_RELOAD, TGT_MPATH, mpp, params, ADDMAP_RW);
+       if (!r) {
+               if (errno != EROFS)
+                       return 0;
+               r = dm_addmap(DM_DEVICE_RELOAD, TGT_MPATH, mpp,
+                             params, ADDMAP_RO);
+       }
+       if (r)
+               r = dm_simplecmd(DM_DEVICE_RESUME, mpp->alias, flush,
+                                1, udev_flags, 0);
+       return r;
 }
 
 extern int

diff --git a/libmultipath/devmapper.h b/libmultipath/devmapper.h
index bc13b07..b5df369 100644 (file)
--- a/libmultipath/devmapper.h
+++ b/libmultipath/devmapper.h
@@ -18,7 +18,7 @@ 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);
 int dm_addmap_create (struct multipath *mpp, char *params);
-int dm_addmap_reload (struct multipath *mpp, char *params);
+int dm_addmap_reload (struct multipath *mpp, char *params, int flush);
 int dm_map_present (const char *);
 int dm_get_map(const char *, unsigned long long *, char *);
 int dm_get_status(char *, char *);