diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index 29542edbc992..5ca1d9c0c657 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -43,6 +43,14 @@ static DECLARE_RWSEM(o2hb_callback_sem); * whenever any of the threads sees activity from the node in its region. */ static DEFINE_SPINLOCK(o2hb_live_lock); +/* + * Serializes region pin/unpin dependency management (o2hb_dependent_users + * and the o2nm_depend_item()/o2nm_undepend_item() calls). o2hb_region_pin() + * has to drop o2hb_live_lock across the sleeping o2nm_depend_item(), so the + * spinlock alone can no longer keep pin and unpin mutually exclusive; this + * mutex, taken outside o2hb_live_lock, does. + */ +static DEFINE_MUTEX(o2hb_dependency_mutex); static struct list_head o2hb_live_slots[O2NM_MAX_NODES]; static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)]; static LIST_HEAD(o2hb_node_events); @@ -2172,6 +2180,7 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group, * If global heartbeat active and there are dependent users, * pin all regions if quorum region count <= CUT_OFF */ + mutex_lock(&o2hb_dependency_mutex); spin_lock(&o2hb_live_lock); if (!o2hb_dependent_users) @@ -2183,6 +2192,7 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group, unlock: spin_unlock(&o2hb_live_lock); + mutex_unlock(&o2hb_dependency_mutex); } static ssize_t o2hb_heartbeat_group_dead_threshold_show(struct config_item *item, @@ -2322,46 +2332,108 @@ EXPORT_SYMBOL_GPL(o2hb_setup_callback); */ static int o2hb_region_pin(const char *region_uuid) { - int ret = 0, found = 0; - struct o2hb_region *reg; + int ret = 0, found; + struct o2hb_region *reg, *pinned; char *uuid; assert_spin_locked(&o2hb_live_lock); - list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) { - if (reg->hr_item_dropped) - continue; + do { + found = 0; + pinned = NULL; - uuid = config_item_name(®->hr_item); - - /* local heartbeat */ - if (region_uuid) { - if (strcmp(region_uuid, uuid)) + list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) { + if (reg->hr_item_dropped) continue; - found = 1; + + uuid = config_item_name(®->hr_item); + + /* local heartbeat */ + if (region_uuid) { + if (strcmp(region_uuid, uuid)) + continue; + found = 1; + } + + if (reg->hr_item_pinned || reg->hr_item_dropped) { + if (found) + break; + continue; + } + + /* + * Found a region that needs pinning. Take a reference + * so it stays alive while we drop the lock below. + */ + pinned = reg; + config_item_get(®->hr_item); + break; } - if (reg->hr_item_pinned || reg->hr_item_dropped) - goto skip_pin; + if (!pinned) + break; + + uuid = config_item_name(&pinned->hr_item); + + /* + * o2nm_depend_item() -> configfs_depend_item() can sleep (it + * takes the configfs root inode rwsem), so it must not run + * under o2hb_live_lock. Drop the lock across it; @pinned is + * kept alive by the reference taken above. The region list may + * change while unlocked, so we rescan from the top afterwards. + */ + spin_unlock(&o2hb_live_lock); /* Ignore ENOENT only for local hb (userdlm domain) */ - ret = o2nm_depend_item(®->hr_item); + ret = o2nm_depend_item(&pinned->hr_item); + + spin_lock(&o2hb_live_lock); if (!ret) { - mlog(ML_CLUSTER, "Pin region %s\n", uuid); - reg->hr_item_pinned = 1; - } else { - if (ret == -ENOENT && found) - ret = 0; - else { - mlog(ML_ERROR, "Pin region %s fails with %d\n", - uuid, ret); + /* + * o2hb_live_lock was dropped across o2nm_depend_item(). + * o2hb_set_quorum_device() runs in the heartbeat thread + * without o2hb_dependency_mutex, so for global heartbeat + * it may have crossed O2HB_PIN_CUT_OFF and unpinned the + * regions while we slept. If that happened this pin is + * no longer wanted; undo it and stop rather than + * resurrecting it on the rescan below. + */ + if (!region_uuid && + bitmap_weight(o2hb_quorum_region_bitmap, + O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF) { + o2nm_undepend_item(&pinned->hr_item); + spin_unlock(&o2hb_live_lock); + config_item_put(&pinned->hr_item); + spin_lock(&o2hb_live_lock); break; } + mlog(ML_CLUSTER, "Pin region %s\n", uuid); + pinned->hr_item_pinned = 1; + } else if (ret == -ENOENT && (found || !region_uuid)) { + /* + * For local hb (found): ignore ENOENT from userdlm + * domains as before. For global hb (!region_uuid): + * the region may have been detached from configfs + * while the lock was dropped — skip it and continue + * pinning the remaining regions. + */ + ret = 0; + } else { + mlog(ML_ERROR, "Pin region %s fails with %d\n", + uuid, ret); } -skip_pin: - if (found) - break; - } + + /* + * config_item_put() may drop the last reference and run + * o2hb_region_release(), which also grabs o2hb_live_lock and + * can sleep, so it must happen with the lock released. + */ + spin_unlock(&o2hb_live_lock); + config_item_put(&pinned->hr_item); + spin_lock(&o2hb_live_lock); + + /* local hb pins a single matching region */ + } while (!ret && !region_uuid); return ret; } @@ -2406,6 +2478,7 @@ static int o2hb_region_inc_user(const char *region_uuid) { int ret = 0; + mutex_lock(&o2hb_dependency_mutex); spin_lock(&o2hb_live_lock); /* local heartbeat */ @@ -2428,11 +2501,13 @@ static int o2hb_region_inc_user(const char *region_uuid) unlock: spin_unlock(&o2hb_live_lock); + mutex_unlock(&o2hb_dependency_mutex); return ret; } static void o2hb_region_dec_user(const char *region_uuid) { + mutex_lock(&o2hb_dependency_mutex); spin_lock(&o2hb_live_lock); /* local heartbeat */ @@ -2451,6 +2526,7 @@ static void o2hb_region_dec_user(const char *region_uuid) unlock: spin_unlock(&o2hb_live_lock); + mutex_unlock(&o2hb_dependency_mutex); } int o2hb_register_callback(const char *region_uuid,