[Cluster-devel] [PATCH dlm/next 1/3] fs: dlm: move assert into release function

[Cluster-devel] [PATCH dlm/next 1/3] fs: dlm: move assert into release function

[Alexander Aring]

This patch moves the assert if unhold_lkb() hits lkb->lkb_ref zero into
the release function. Instead of kill_lkb() which has an assert if
lkb->lkb_status is non-zero. The assert in kill_lkb() has nothing todo
with unhold a lkb and probably was only used here to call something if
it it's zero. The unhold_lkb() should never release a lkb so we move the
assert to the release functionality.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lock.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 739f09d0951c..dac7eb75dba9 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1310,6 +1310,13 @@ static inline void hold_lkb(struct dlm_lkb *lkb)
 	kref_get(&lkb->lkb_ref);
 }
 
+static void unhold_lkb_assert(struct kref *kref)
+{
+	struct dlm_lkb *lkb = container_of(kref, struct dlm_lkb, lkb_ref);
+
+	DLM_ASSERT(false, dlm_print_lkb(lkb););
+}
+
 /* This is called when we need to remove a reference and are certain
    it's not the last ref.  e.g. del_lkb is always called between a
    find_lkb/put_lkb and is always the inverse of a previous add_lkb.
@@ -1317,9 +1324,7 @@ static inline void hold_lkb(struct dlm_lkb *lkb)
 
 static inline void unhold_lkb(struct dlm_lkb *lkb)
 {
-	int rv;
-	rv = kref_put(&lkb->lkb_ref, kill_lkb);
-	DLM_ASSERT(!rv, dlm_print_lkb(lkb););
+	kref_put(&lkb->lkb_ref, unhold_lkb_assert);
 }
 
 static void lkb_add_ordered(struct list_head *new, struct list_head *head,
-- 
2.31.1

[Cluster-devel] [PATCH dlm/next 2/3] fs: dlm: fix context imbalance warning in __put_lkb()

[Alexander Aring]

This patch fixes the following sparse warning:

warning: context imbalance in '__put_lkb' - unexpected unlock

it does this by unlock the ls_lkbidr_spin lock inside of the release
functionality of kref_put_lock() and do a __releases() annotation at the
release function. The kref_put_lock() for __put_lkb() has a special
requirement to pass an additional dlm_ls pointer to the release callback,
this is done by providing an own implementation of kref_put_lock() that
is named dlm_kref_put_lock() and can pass an additional parameter.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lock.c | 46 +++++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index dac7eb75dba9..4b5cff76d376 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1256,7 +1256,8 @@ static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret)
 	return lkb ? 0 : -ENOENT;
 }
 
-static void kill_lkb(struct kref *kref)
+static void kill_lkb(struct kref *kref, struct dlm_ls *ls)
+	 __releases(&ls->ls_lkbidr_spin)
 {
 	struct dlm_lkb *lkb = container_of(kref, struct dlm_lkb, lkb_ref);
 
@@ -1264,6 +1265,29 @@ static void kill_lkb(struct kref *kref)
 	   can release the write_lock before the detach_lkb */
 
 	DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb););
+
+	idr_remove(&ls->ls_lkbidr, lkb->lkb_id);
+	spin_unlock(&ls->ls_lkbidr_spin);
+
+	detach_lkb(lkb);
+
+	/* for local/process lkbs, lvbptr points to caller's lksb */
+	if (lkb->lkb_lvbptr && is_master_copy(lkb))
+		dlm_free_lvb(lkb->lkb_lvbptr);
+	dlm_free_lkb(lkb);
+}
+
+static inline int dlm_kref_put_lock(struct kref *kref,
+				    void (*release)(struct kref *kref,
+						    struct dlm_ls *ls),
+				    spinlock_t *lock,
+				    struct dlm_ls *ls)
+{
+	if (refcount_dec_and_lock(&kref->refcount, lock)) {
+		release(kref, ls);
+		return 1;
+	}
+	return 0;
 }
 
 /* __put_lkb() is used when an lkb may not have an rsb attached to
@@ -1271,24 +1295,8 @@ static void kill_lkb(struct kref *kref)
 
 static int __put_lkb(struct dlm_ls *ls, struct dlm_lkb *lkb)
 {
-	uint32_t lkid = lkb->lkb_id;
-	int rv;
-
-	rv = kref_put_lock(&lkb->lkb_ref, kill_lkb,
-			   &ls->ls_lkbidr_spin);
-	if (rv) {
-		idr_remove(&ls->ls_lkbidr, lkid);
-		spin_unlock(&ls->ls_lkbidr_spin);
-
-		detach_lkb(lkb);
-
-		/* for local/process lkbs, lvbptr points to caller's lksb */
-		if (lkb->lkb_lvbptr && is_master_copy(lkb))
-			dlm_free_lvb(lkb->lkb_lvbptr);
-		dlm_free_lkb(lkb);
-	}
-
-	return rv;
+	return dlm_kref_put_lock(&lkb->lkb_ref, kill_lkb,
+				 &ls->ls_lkbidr_spin, ls);
 }
 
 int dlm_put_lkb(struct dlm_lkb *lkb)
-- 
2.31.1

[Cluster-devel] [PATCH dlm/next 3/3] fs: dlm: fix context imbalance warning in put_rsb()

[Alexander Aring]

This patch fixes the following sparse warning:

warning: context imbalance in 'put_rsb' - unexpected unlock

it does this by unlock the ls_rsbtbl[bucket].lock lock inside of the
release functionality of kref_put_lock() and do a __releases() annotation
at the release function.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
---
 fs/dlm/lock.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 4b5cff76d376..70ee15c44bd2 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -352,12 +352,9 @@ static void put_rsb(struct dlm_rsb *r)
 {
 	struct dlm_ls *ls = r->res_ls;
 	uint32_t bucket = r->res_bucket;
-	int rv;
 
-	rv = kref_put_lock(&r->res_ref, toss_rsb,
-			   &ls->ls_rsbtbl[bucket].lock);
-	if (rv)
-		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
+	kref_put_lock(&r->res_ref, toss_rsb,
+		      &ls->ls_rsbtbl[bucket].lock);
 }
 
 void dlm_put_rsb(struct dlm_rsb *r)
@@ -1140,20 +1137,24 @@ void dlm_dump_rsb_name(struct dlm_ls *ls, char *name, int len)
 }
 
 static void toss_rsb(struct kref *kref)
+	__releases(&ls->ls_rsbtbl[bucket].lock)
 {
 	struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref);
+	uint32_t bucket = r->res_bucket;
 	struct dlm_ls *ls = r->res_ls;
 
 	DLM_ASSERT(list_empty(&r->res_root_list), dlm_print_rsb(r););
 	kref_init(&r->res_ref);
-	rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[r->res_bucket].keep);
-	rsb_insert(r, &ls->ls_rsbtbl[r->res_bucket].toss);
+	rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[bucket].keep);
+	rsb_insert(r, &ls->ls_rsbtbl[bucket].toss);
 	r->res_toss_time = jiffies;
-	ls->ls_rsbtbl[r->res_bucket].flags |= DLM_RTF_SHRINK;
+	ls->ls_rsbtbl[bucket].flags |= DLM_RTF_SHRINK;
 	if (r->res_lvbptr) {
 		dlm_free_lvb(r->res_lvbptr);
 		r->res_lvbptr = NULL;
 	}
+
+	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
 }
 
 /* See comment for unhold_lkb */
-- 
2.31.1