A subsequent patch will use this mechanism to wake up an operation
that is waiting for a client to return a delegation.
The new tracepoint records whether the wait timed out or was
properly awoken by the expected DELEGRETURN.
Suggested-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 31 +++++++++++++++++++++++++++++++
fs/nfsd/nfsd.h | 1 +
fs/nfsd/trace.h | 23 +++++++++++++++++++++++
fs/nfsd/xdr4.h | 2 ++
4 files changed, 57 insertions(+)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 0cf5a4bb36df..9d5140d485d4 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4689,6 +4689,36 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
return ret;
}
+static bool nfsd4_deleg_present(struct inode *inode)
+{
+ struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx);
+
+ return ctx && !list_empty_careful(&ctx->flc_lease);
+}
+
+/**
+ * nfsd4_wait_for_delegreturn - wait for delegations to be returned
+ * @rqstp: the RPC transaction being executed
+ * @fhp: instantiated filehandle of the file being waited for
+ *
+ * The timeout prevents deadlock if all nfsd threads happen to be
+ * tied up waiting for returning delegations.
+ *
+ * Return values:
+ * %true: delegation was returned
+ * %false: timed out waiting for delegreturn
+ */
+bool nfsd4_wait_for_delegreturn(struct svc_rqst *rqstp, struct svc_fh *fhp)
+{
+ struct inode *inode = d_inode(fhp->fh_dentry);
+ long __maybe_unused timeo;
+
+ timeo = wait_var_event_timeout(inode, !nfsd4_deleg_present(inode),
+ NFSD_DELEGRETURN_TIMEOUT);
+ trace_nfsd_delegreturn_wakeup(rqstp, fhp, timeo);
+ return timeo > 0;
+}
+
static void nfsd4_cb_recall_prepare(struct nfsd4_callback *cb)
{
struct nfs4_delegation *dp = cb_to_delegation(cb);
@@ -6703,6 +6733,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
if (status)
goto put_stateid;
+ wake_up_var(d_inode(cstate->current_fh.fh_dentry));
destroy_delegation(dp);
put_stateid:
nfs4_put_stid(&dp->dl_stid);
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 9a8b09afc173..05abfb6a0271 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -341,6 +341,7 @@ void nfsd_lockd_shutdown(void);
#define NFSD_LAUNDROMAT_MINTIMEOUT 1 /* seconds */
#define NFSD_COURTESY_CLIENT_TIMEOUT (24 * 60 * 60) /* seconds */
+#define NFSD_DELEGRETURN_TIMEOUT (HZ / 34) /* 30ms */
/*
* The following attributes are currently not supported by the NFSv4 server:
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 6809d92d4cc5..a88f4303fbd9 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -538,6 +538,29 @@ DEFINE_NFSD_COPY_ERR_EVENT(clone_file_range_err);
#include "filecache.h"
#include "vfs.h"
+TRACE_EVENT(nfsd_delegreturn_wakeup,
+ TP_PROTO(
+ const struct svc_rqst *rqstp,
+ const struct svc_fh *fhp,
+ long timeo
+ ),
+ TP_ARGS(rqstp, fhp, timeo),
+ TP_STRUCT__entry(
+ __field(u32, xid)
+ __field(u32, fh_hash)
+ __field(long, timeo)
+ ),
+ TP_fast_assign(
+ __entry->xid = be32_to_cpu(rqstp->rq_xid);
+ __entry->fh_hash = knfsd_fh_hash(&fhp->fh_handle);
+ __entry->timeo = timeo;
+ ),
+ TP_printk("xid=0x%08x fh_hash=0x%08x%s",
+ __entry->xid, __entry->fh_hash,
+ __entry->timeo == 0 ? " (timed out)" : ""
+ )
+);
+
DECLARE_EVENT_CLASS(nfsd_stateid_class,
TP_PROTO(stateid_t *stp),
TP_ARGS(stp),
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 7b744011f2d3..7323433746f1 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -788,6 +788,8 @@ extern __be32 nfsd4_destroy_clientid(struct svc_rqst *, struct nfsd4_compound_st
union nfsd4_op_u *u);
__be32 nfsd4_reclaim_complete(struct svc_rqst *, struct nfsd4_compound_state *,
union nfsd4_op_u *u);
+extern bool nfsd4_wait_for_delegreturn(struct svc_rqst *rqstp,
+ struct svc_fh *fhp);
extern __be32 nfsd4_process_open1(struct nfsd4_compound_state *,
struct nfsd4_open *open, struct nfsd_net *nn);
extern __be32 nfsd4_process_open2(struct svc_rqst *rqstp,
