5.4-stable review patch. If anyone has any objections, please let me know.
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From: Olga Kornievskaia okorniev@redhat.com
commit a082e4b4d08a4a0e656d90c2c05da85f23e6d0c9 upstream.
When v3 NLM request finds a conflicting delegation, it triggers a delegation recall and nfsd_open fails with EAGAIN. nfsd_open then translates EAGAIN into nfserr_jukebox. In nlm_fopen, instead of returning nlm_failed for when there is a conflicting delegation, drop this NLM request so that the client retries. Once delegation is recalled and if a local lock is claimed, a retry would lead to nfsd returning a nlm_lck_blocked error or a successful nlm lock.
Fixes: d343fce148a4 ("[PATCH] knfsd: Allow lockd to drop replies as appropriate") Cc: stable@vger.kernel.org # v6.6 Signed-off-by: Olga Kornievskaia okorniev@redhat.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/lockd.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
--- a/fs/nfsd/lockd.c +++ b/fs/nfsd/lockd.c @@ -44,6 +44,21 @@ nlm_fopen(struct svc_rqst *rqstp, struct switch (nfserr) { case nfs_ok: return 0; + case nfserr_jukebox: + /* this error can indicate a presence of a conflicting + * delegation to an NLM lock request. Options are: + * (1) For now, drop this request and make the client + * retry. When delegation is returned, client's lock retry + * will complete. + * (2) NLM4_DENIED as per "spec" signals to the client + * that the lock is unavailable now but client can retry. + * Linux client implementation does not. It treats + * NLM4_DENIED same as NLM4_FAILED and errors the request. + * (3) For the future, treat this as blocked lock and try + * to callback when the delegation is returned but might + * not have a proper lock request to block on. + */ + fallthrough; case nfserr_dropit: return nlm_drop_reply; case nfserr_stale: