5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joseph Qi commit cd789996db3c87427343f54f509d17810bd7ba7c upstream. o2hb_heartbeat_group_drop_item() is called from configfs rmdir with the parent directory's inode_lock held. It calls o2hb_region_pin() -> o2nm_depend_item() -> configfs_depend_item(), which acquires the configfs root inode_lock. This creates a parent -> root inode_lock nesting that could deadlock against paths taking root -> parent (e.g. subsystem unregistration). Fix this by using configfs_depend_item_unlocked() when o2hb_region_pin() is called from a configfs callback context. This variant skips the root inode_lock when caller and target are in the same subsystem, which is safe because VFS already holds a lock preventing unregistration. Add o2nm_depend_item_unlocked() wrapper and a from_callback parameter to o2hb_region_pin() to select the appropriate variant. Link: https://lore.kernel.org/20260722124933.430554-3-joseph.qi@linux.alibaba.com Fixes: 58a3158a5d17 ("ocfs2/cluster: Pin/unpin o2hb regions") Signed-off-by: Joseph Qi Cc: Changwei Ge Cc: Heming Zhao Cc: Joel Becker Cc: Jun Piao Cc: Junxiao Bi Cc: Mark Fasheh Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/cluster/heartbeat.c | 17 ++++++++++------- fs/ocfs2/cluster/nodemanager.c | 6 ++++++ fs/ocfs2/cluster/nodemanager.h | 1 + 3 files changed, 17 insertions(+), 7 deletions(-) --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -147,7 +147,7 @@ static unsigned int o2hb_dependent_users * In global heartbeat mode, we pin/unpin all o2hb regions. This solution * works for both file system and userdlm domains. */ -static int o2hb_region_pin(const char *region_uuid); +static int o2hb_region_pin(const char *region_uuid, bool from_callback); static void o2hb_region_unpin(const char *region_uuid); /* Only sets a new threshold if there are no active regions. @@ -2134,7 +2134,7 @@ static void o2hb_heartbeat_group_drop_it if (bitmap_weight(o2hb_quorum_region_bitmap, O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF) - o2hb_region_pin(NULL); + o2hb_region_pin(NULL, true); unlock: spin_unlock(&o2hb_live_lock); @@ -2275,7 +2275,7 @@ EXPORT_SYMBOL_GPL(o2hb_setup_callback); * In local, we only pin the matching region. In global we pin all the active * regions. */ -static int o2hb_region_pin(const char *region_uuid) +static int o2hb_region_pin(const char *region_uuid, bool from_callback) { int ret = 0, found; struct o2hb_region *reg, *pinned; @@ -2330,7 +2330,10 @@ static int o2hb_region_pin(const char *r spin_unlock(&o2hb_live_lock); /* Ignore ENOENT only for local hb (userdlm domain) */ - ret = o2nm_depend_item(&pinned->hr_item); + if (from_callback) + ret = o2nm_depend_item_unlocked(&pinned->hr_item); + else + ret = o2nm_depend_item(&pinned->hr_item); spin_lock(&o2hb_live_lock); if (!ret) { @@ -2428,8 +2431,8 @@ static int o2hb_region_inc_user(const ch /* local heartbeat */ if (!o2hb_global_heartbeat_active()) { - ret = o2hb_region_pin(region_uuid); - goto unlock; + ret = o2hb_region_pin(region_uuid, false); + goto unlock; } /* @@ -2442,7 +2445,7 @@ static int o2hb_region_inc_user(const ch if (bitmap_weight(o2hb_quorum_region_bitmap, O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF) - ret = o2hb_region_pin(NULL); + ret = o2hb_region_pin(NULL, false); unlock: spin_unlock(&o2hb_live_lock); --- a/fs/ocfs2/cluster/nodemanager.c +++ b/fs/ocfs2/cluster/nodemanager.c @@ -778,6 +778,12 @@ int o2nm_depend_item(struct config_item return configfs_depend_item(&o2nm_cluster_group.cs_subsys, item); } +int o2nm_depend_item_unlocked(struct config_item *item) +{ + return configfs_depend_item_unlocked(&o2nm_cluster_group.cs_subsys, + item); +} + void o2nm_undepend_item(struct config_item *item) { configfs_undepend_item(item); --- a/fs/ocfs2/cluster/nodemanager.h +++ b/fs/ocfs2/cluster/nodemanager.h @@ -66,6 +66,7 @@ void o2nm_node_get(struct o2nm_node *nod void o2nm_node_put(struct o2nm_node *node); int o2nm_depend_item(struct config_item *item); +int o2nm_depend_item_unlocked(struct config_item *item); void o2nm_undepend_item(struct config_item *item); int o2nm_depend_this_node(void); void o2nm_undepend_this_node(void);