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Commit c7226e40 authored by David Howells's avatar David Howells
Browse files

afs: Fix lock-wait/callback-break double locking 



__afs_break_callback() holds vnode->lock around its call of
afs_lock_may_be_available() - which also takes that lock.

Fix this by not taking the lock in __afs_break_callback().

Also, there's no point checking the granted_locks and pending_locks queues;
it's sufficient to check lock_state, so move that check out of
afs_lock_may_be_available() into __afs_break_callback() to replace the
queue checks.

Fixes: e8d6c554 ("AFS: implement file locking")
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent d9052dda

fs/afs/callback.c

+1 −7
Original line number Diff line number Diff line
@@ -218,14 +218,8 @@ void __afs_break_callback(struct afs_vnode *vnode) 
		vnode->cb_break++;

		afs_clear_permits(vnode);



		spin_lock(&vnode->lock);



		_debug("break callback");



		if (list_empty(&vnode->granted_locks) &&

		    !list_empty(&vnode->pending_locks))

		if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)

			afs_lock_may_be_available(vnode);

		spin_unlock(&vnode->lock);

	}

}

fs/afs/flock.c

+0 −3
Original line number Diff line number Diff line
@@ -41,9 +41,6 @@ void afs_lock_may_be_available(struct afs_vnode *vnode) 
{

	_enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode);



	if (vnode->lock_state != AFS_VNODE_LOCK_WAITING_FOR_CB)

		return;



	spin_lock(&vnode->lock);

	if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB)

		afs_next_locker(vnode, 0);