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Commit 88974691 authored by Jeff Layton's avatar Jeff Layton Committed by Al Viro
Browse files

locks: encapsulate the fl_link list handling 



Move the fl_link list handling routines into a separate set of helpers.
Also ensure that locks and requests are always put on global lists
last (after fully initializing them) and are taken off before unintializing
them.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b9746ef8

fs/locks.c

+36 −9
Original line number Diff line number Diff line
@@ -153,13 +153,15 @@ int lease_break_time = 45; 
#define for_each_lock(inode, lockp) \

	for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)



/* The global file_lock_list is only used for displaying /proc/locks. */

static LIST_HEAD(file_lock_list);



/* The blocked_list is used to find POSIX lock loops for deadlock detection. */

static LIST_HEAD(blocked_list);



/* Protects the two list heads above, plus the inode->i_flock list */

static DEFINE_SPINLOCK(file_lock_lock);



/*

 * Protects the two list heads above, plus the inode->i_flock list

 */

void lock_flocks(void)

{

	spin_lock(&file_lock_lock);
@@ -484,13 +486,37 @@ static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) 
	return fl1->fl_owner == fl2->fl_owner;

}



static inline void

locks_insert_global_locks(struct file_lock *fl)

{

	list_add_tail(&fl->fl_link, &file_lock_list);

}



static inline void

locks_delete_global_locks(struct file_lock *fl)

{

	list_del_init(&fl->fl_link);

}



static inline void

locks_insert_global_blocked(struct file_lock *waiter)

{

	list_add(&waiter->fl_link, &blocked_list);

}



static inline void

locks_delete_global_blocked(struct file_lock *waiter)

{

	list_del_init(&waiter->fl_link);

}



/* Remove waiter from blocker's block list.

 * When blocker ends up pointing to itself then the list is empty.

 */

static void __locks_delete_block(struct file_lock *waiter)

{

	locks_delete_global_blocked(waiter);

	list_del_init(&waiter->fl_block);

	list_del_init(&waiter->fl_link);

	waiter->fl_next = NULL;

}
@@ -512,10 +538,10 @@ static void locks_insert_block(struct file_lock *blocker, 
			       struct file_lock *waiter)

{

	BUG_ON(!list_empty(&waiter->fl_block));

	list_add_tail(&waiter->fl_block, &blocker->fl_block);

	waiter->fl_next = blocker;

	list_add_tail(&waiter->fl_block, &blocker->fl_block);

	if (IS_POSIX(blocker))

		list_add(&waiter->fl_link, &blocked_list);

		locks_insert_global_blocked(request);

}



/*
@@ -543,13 +569,13 @@ static void locks_wake_up_blocks(struct file_lock *blocker) 
 */

static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)

{

	list_add(&fl->fl_link, &file_lock_list);



	fl->fl_nspid = get_pid(task_tgid(current));



	/* insert into file's list */

	fl->fl_next = *pos;

	*pos = fl;



	locks_insert_global_locks(fl);

}



/*
@@ -562,9 +588,10 @@ static void locks_delete_lock(struct file_lock **thisfl_p) 
{

	struct file_lock *fl = *thisfl_p;



	locks_delete_global_locks(fl);



	*thisfl_p = fl->fl_next;

	fl->fl_next = NULL;

	list_del_init(&fl->fl_link);



	if (fl->fl_nspid) {

		put_pid(fl->fl_nspid);