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-rw-r--r--fs/nilfs2/segment.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 7cb34e1c9206..b6c3c5f8628e 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2168,19 +2168,28 @@ static int nilfs_segctor_sync(struct nilfs_sc_info *sci)
struct nilfs_segctor_wait_request wait_req;
int err = 0;
- spin_lock(&sci->sc_state_lock);
init_wait(&wait_req.wq);
wait_req.err = 0;
atomic_set(&wait_req.done, 0);
+ init_waitqueue_entry(&wait_req.wq, current);
+
+ /*
+ * To prevent a race issue where completion notifications from the
+ * log writer thread are missed, increment the request sequence count
+ * "sc_seq_request" and insert a wait queue entry using the current
+ * sequence number into the "sc_wait_request" queue at the same time
+ * within the lock section of "sc_state_lock".
+ */
+ spin_lock(&sci->sc_state_lock);
wait_req.seq = ++sci->sc_seq_request;
+ add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
spin_unlock(&sci->sc_state_lock);
- init_waitqueue_entry(&wait_req.wq, current);
- add_wait_queue(&sci->sc_wait_request, &wait_req.wq);
- set_current_state(TASK_INTERRUPTIBLE);
wake_up(&sci->sc_wait_daemon);
for (;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
if (atomic_read(&wait_req.done)) {
err = wait_req.err;
break;