+ spinlock_t *lock = ext4_group_lock_ptr(sb, group);
+ if (spin_trylock(lock))
+ /*
+ * We're able to grab the lock right away, so drop the
+ * lock contention counter.
+ */
+ atomic_add_unless(&EXT4_SB(sb)->s_lock_busy, -1, 0);
+ else {
+ /*
+ * The lock is busy, so bump the contention counter,
+ * and then wait on the spin lock.
+ */
+ atomic_add_unless(&EXT4_SB(sb)->s_lock_busy, 1,
+ EXT4_MAX_CONTENTION);
+ spin_lock(lock);
+ }