[for-6.13 PATCH 18/19] nfs: probe for LOCALIO when v4 client reconnects to server

[Mike Snitzer <snitzer@kernel.org>]

Introduce nfs_local_probe_async() for the NFS client to initiate
if/when it reconnects with server.  For NFSv4 it is a simple matter to
call nfs_local_probe_async() from nfs4_do_reclaim (during NFSv4
grace).

[NFSv3 also needs to reestablish LOCALIO if/when a client reconnects
 to server, but the stateless nature of v3 means the implementation is
 more tricky so its been factored out to the following commit.]

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 fs/nfs/internal.h         |  2 ++
 fs/nfs/localio.c          | 15 +++++++++++++++
 fs/nfs/nfs4state.c        |  1 +
 include/linux/nfs_fs_sb.h |  1 +
 4 files changed, 19 insertions(+)

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 57af3ab3adbe..efd42efd9405 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -456,6 +456,7 @@ extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);
 /* localio.c */
 extern void nfs_local_disable(struct nfs_client *);
 extern void nfs_local_probe(struct nfs_client *);
+extern void nfs_local_probe_async(struct nfs_client *);
 extern struct nfsd_file *nfs_local_open_fh(struct nfs_client *,
 					   const struct cred *,
 					   struct nfs_fh *,
@@ -473,6 +474,7 @@ extern bool nfs_server_is_local(const struct nfs_client *clp);
 #else /* CONFIG_NFS_LOCALIO */
 static inline void nfs_local_disable(struct nfs_client *clp) {}
 static inline void nfs_local_probe(struct nfs_client *clp) {}
+static inline void nfs_local_probe_async(struct nfs_client *clp) {}
 static inline struct nfsd_file *
 nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
 		  struct nfs_fh *fh, struct nfs_file_localio *nfl,
diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index d10d863aaf23..710e537b3402 100644
--- a/fs/nfs/localio.c
+++ b/fs/nfs/localio.c
@@ -214,6 +214,21 @@ void nfs_local_probe(struct nfs_client *clp)
 }
 EXPORT_SYMBOL_GPL(nfs_local_probe);
 
+static void nfs_local_probe_async_work(struct work_struct *work)
+{
+	struct nfs_client *clp =
+		container_of(work, struct nfs_client, cl_local_probe_work);
+
+	nfs_local_probe(clp);
+}
+
+void nfs_local_probe_async(struct nfs_client *clp)
+{
+	INIT_WORK(&clp->cl_local_probe_work, nfs_local_probe_async_work);
+	queue_work(nfsiod_workqueue, &clp->cl_local_probe_work);
+}
+EXPORT_SYMBOL_GPL(nfs_local_probe_async);
+
 static inline struct nfsd_file *nfs_local_file_get(struct nfsd_file *nf)
 {
 	return nfs_to->nfsd_file_get(nf);
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index dafd61186557..2ebb9ac56b7b 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1957,6 +1957,7 @@ static int nfs4_do_reclaim(struct nfs_client *clp, const struct nfs4_state_recov
 	}
 	rcu_read_unlock();
 	nfs4_free_state_owners(&freeme);
+	nfs_local_probe_async(clp);
 	if (lost_locks)
 		pr_warn("NFS: %s: lost %d locks\n",
 			clp->cl_hostname, lost_locks);
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 239d86ef166c..63d7e0f478d8 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -132,6 +132,7 @@ struct nfs_client {
 	struct timespec64	cl_nfssvc_boot;
 	seqlock_t		cl_boot_lock;
 	nfs_uuid_t		cl_uuid;
+	struct work_struct	cl_local_probe_work;
 #endif /* CONFIG_NFS_LOCALIO */
 };
 
-- 
2.44.0