Programming

static void ext3_write_super (struct super_block * sb)
{
        if (mutex_trylock(&sb->s_lock) != 0)
                BUG();
        sb->s_dirt = 0;
}

//File:kernel/mutex.c of Linux kernel 2.6.27.59

/***
 * mutex_trylock - try acquire the mutex, without waiting
 * @lock: the mutex to be acquired
 *
 * Try to acquire the mutex atomically. Returns 1 if the mutex
 * has been acquired successfully, and 0 on contention.
 *
 * NOTE: this function follows the spin_trylock() convention, so
 * it is negated to the down_trylock() return values! Be careful
 * about this when converting semaphore users to mutexes.
 *
 * This function must not be used in interrupt context. The
 * mutex must be released by the same task that acquired it.
 */
int __sched mutex_trylock(struct mutex *lock)
{
        return __mutex_fastpath_trylock(&lock->count,
                                        __mutex_trylock_slowpath);
}