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Date: Thu, 16 Jan 2020 12:00:00 -0500 From: Sasha Levin <sashal@...nel.org> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: David Howells <dhowells@...hat.com>, Sasha Levin <sashal@...nel.org>, linux-afs@...ts.infradead.org Subject: [PATCH AUTOSEL 4.19 362/671] afs: Fix lock-wait/callback-break double locking From: David Howells <dhowells@...hat.com> [ Upstream commit c7226e407b6065d3bda8bd9dc627663d2c505ea3 ] __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: e8d6c554126b ("AFS: implement file locking") Signed-off-by: David Howells <dhowells@...hat.com> Signed-off-by: Sasha Levin <sashal@...nel.org> --- fs/afs/callback.c | 8 +------- fs/afs/flock.c | 3 --- 2 files changed, 1 insertion(+), 10 deletions(-) diff --git a/fs/afs/callback.c b/fs/afs/callback.c index 4ad701250299..97283b04fa6f 100644 --- a/fs/afs/callback.c +++ b/fs/afs/callback.c @@ -221,14 +221,8 @@ 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); } write_sequnlock(&vnode->cb_lock); diff --git a/fs/afs/flock.c b/fs/afs/flock.c index 075fe7f94810..457ce62e5c0f 100644 --- a/fs/afs/flock.c +++ b/fs/afs/flock.c @@ -39,9 +39,6 @@ void afs_lock_may_be_available(struct afs_vnode *vnode) { _enter("{%x:%u}", 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); -- 2.20.1
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