From b036727d334b1b7cd4c1f1fba3b59ba93a6bbe96 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 26 May 2026 12:38:46 -0400 Subject: [PATCH] nfsd: clear CALLBACK_RUNNING on failed delegation recall queue nfsd_break_one_deleg() sets NFSD4_CALLBACK_RUNNING via test_and_set_bit at entry to serialize recall work, then calls nfsd4_run_cb() to queue the recall. When the queue attempt fails the refcount bump is undone, but the RUNNING bit is left set. The only site that clears the bit is nfsd41_destroy_cb() (fs/nfsd/nfs4callback.c), which runs from the workqueue and is therefore unreachable when nothing was queued. The bit becomes a permanent latch on dp->dl_recall.cb_flags: every subsequent break_lease() on the same delegation hits the early-return guard in nfsd_break_one_deleg() and silently skips the recall, so the delegation is never broken and the conflicting open or lock stalls. Fix by clearing NFSD4_CALLBACK_RUNNING on the !queued branch alongside the refcount_dec. Fixes: 1054e8ffc5c4 ("nfsd: prevent callback tasks running concurrently") Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260526-cb_recall_any_callback_running_stuck-v1-2-310011a028f3@kernel.org Signed-off-by: Chuck Lever --- fs/nfsd/nfs4state.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index b8c2a041ec4b..c7eb558cb86b 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -5631,8 +5631,10 @@ static void nfsd_break_one_deleg(struct nfs4_delegation *dp) refcount_inc(&dp->dl_stid.sc_count); queued = nfsd4_run_cb(&dp->dl_recall); WARN_ON_ONCE(!queued); - if (!queued) + if (!queued) { refcount_dec(&dp->dl_stid.sc_count); + clear_bit(NFSD4_CALLBACK_RUNNING, &dp->dl_recall.cb_flags); + } } /* Called from break_lease() with flc_lock held. */