/*
* Update on-disk file size now that data has been written to disk.
*/
STATIC int
xfs_setfilesize(
struct xfs_ioend *ioend)
{
struct xfs_inode *ip = XFS_I(ioend->io_inode);
struct xfs_trans *tp = ioend->io_append_trans;
xfs_fsize_t isize;
/*
* The transaction may have been allocated in the I/O submission thread,
* thus we need to mark ourselves as beeing in a transaction manually.
* Similarly for freeze protection.
*/
current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
rwsem_acquire_read(&VFS_I(ip)->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
0, 1, _THIS_IP_);
xfs_ilock(ip, XFS_ILOCK_EXCL);
isize = xfs_new_eof(ip, ioend->io_offset + ioend->io_size);
if (!isize) {
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_trans_cancel(tp, 0);
return 0;
}
trace_xfs_setfilesize(ip, ioend->io_offset, ioend->io_size);
ip->i_d.di_size = isize;
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
return xfs_trans_commit(tp, 0);
}
/*
* lock for reading
*/
void __sched down_read(struct rw_semaphore *sem)
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}
void down_read_nested(struct rw_semaphore *sem, int subclass)
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}
/*
* trylock for reading -- returns 1 if successful, 0 if contention
*/
int down_read_trylock(struct rw_semaphore *sem)
{
int ret = __down_read_trylock(sem);
if (ret == 1)
rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
int down_read_trylock_nested(struct rw_semaphore *sem, int subclass)
{
int ret = __down_read_trylock(sem);
if (ret == 1)
rwsem_acquire_read(&sem->dep_map, subclass, 1, _RET_IP_);
return ret;
}
static void __rt_down_read(struct rw_semaphore *rwsem, int subclass)
{
struct rt_mutex *lock = &rwsem->lock;
rwsem_acquire_read(&rwsem->dep_map, subclass, 0, _RET_IP_);
if (rt_mutex_real_owner(lock) != current)
rt_mutex_lock(&rwsem->lock);
rwsem->read_depth++;
}
/**
* kernfs_get_active - get an active reference to kernfs_node
* @kn: kernfs_node to get an active reference to
*
* Get an active reference of @kn. This function is noop if @kn
* is NULL.
*
* RETURNS:
* Pointer to @kn on success, NULL on failure.
*/
struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
{
if (unlikely(!kn))
return NULL;
if (!atomic_inc_unless_negative(&kn->active))
return NULL;
if (kn->flags & KERNFS_LOCKDEP)
rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
return kn;
}
/**
* sysfs_get_active - get an active reference to sysfs_dirent
* @sd: sysfs_dirent to get an active reference to
*
* Get an active reference of @sd. This function is noop if @sd
* is NULL.
*
* RETURNS:
* Pointer to @sd on success, NULL on failure.
*/
struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
{
if (unlikely(!sd))
return NULL;
if (!atomic_inc_unless_negative(&sd->s_active))
return NULL;
if (likely(!sysfs_ignore_lockdep(sd)))
rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
return sd;
}
STATIC int
xfs_setfilesize_ioend(
struct xfs_ioend *ioend)
{
struct xfs_inode *ip = XFS_I(ioend->io_inode);
struct xfs_trans *tp = ioend->io_append_trans;
/*
* The transaction may have been allocated in the I/O submission thread,
* thus we need to mark ourselves as being in a transaction manually.
* Similarly for freeze protection.
*/
current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
rwsem_acquire_read(&VFS_I(ip)->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
0, 1, _THIS_IP_);
return xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
}
static void __rt_down_read(struct rw_semaphore *rwsem, int subclass)
{
unsigned long flags;
rwsem_acquire_read(&rwsem->dep_map, subclass, 0, _RET_IP_);
/*
* Read locks within the write lock succeed.
*/
spin_lock_irqsave(&rwsem->lock.wait_lock, flags);
if (rt_mutex_real_owner(&rwsem->lock) == current) {
spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags);
rwsem->read_depth++;
return;
}
spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags);
rt_mutex_lock(&rwsem->lock);
}
int fastcall rt_down_read_trylock(struct rw_semaphore *rwsem)
{
unsigned long flags;
int ret;
/*
* Read locks within the self-held write lock succeed.
*/
spin_lock_irqsave(&rwsem->lock.wait_lock, flags);
if (rt_mutex_real_owner(&rwsem->lock) == current) {
spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags);
rwsem_acquire_read(&rwsem->dep_map, 0, 1, _RET_IP_);
rwsem->read_depth++;
return 1;
}
spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags);
ret = rt_mutex_trylock(&rwsem->lock);
if (ret)
rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
return ret;
}
/**
* sysfs_get_active - get an active reference to sysfs_dirent
* @sd: sysfs_dirent to get an active reference to
*
* Get an active reference of @sd. This function is noop if @sd
* is NULL.
*
* RETURNS:
* Pointer to @sd on success, NULL on failure.
*/
struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
{
if (unlikely(!sd))
return NULL;
while (1) {
int v, t;
v = atomic_read(&sd->s_active);
if (unlikely(v < 0))
return NULL;
t = atomic_cmpxchg(&sd->s_active, v, v + 1);
if (likely(t == v)) {
rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
return sd;
}
if (t < 0)
return NULL;
cpu_relax();
}
}
