From: Trond Myklebust Date: Fri, 2 Oct 2015 15:11:16 +0000 (-0400) Subject: NFSv4: Don't try to reclaim unused state owners X-Git-Tag: v4.9.8~3443^2~5 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4a0954ef347de7409ddf8f8153d893827d3feba8;p=platform%2Fkernel%2Flinux-rpi3.git NFSv4: Don't try to reclaim unused state owners Currently, we don't test if the state owner is in use before we try to recover it. The problem is that if the refcount is zero, then the state owner will be waiting on the lru list for garbage collection. The expectation in that case is that if you bump the refcount, then you must also remove the state owner from the lru list. Otherwise the call to nfs4_put_state_owner will corrupt that list by trying to add our state owner a second time. Avoid the whole problem by just skipping state owners that hold no state. Reported-by: Andrew W Elble Signed-off-by: Trond Myklebust --- diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 5db3246..d854693 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1725,7 +1725,8 @@ restart: if (!test_and_clear_bit(ops->owner_flag_bit, &sp->so_flags)) continue; - atomic_inc(&sp->so_count); + if (!atomic_inc_not_zero(&sp->so_count)) + continue; spin_unlock(&clp->cl_lock); rcu_read_unlock();