netdev - [PATCH v3 31/32] NFSD: NFSv4 CLOSE should release an nfsd

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Date:   Fri, 08 Jul 2022 14:27:02 -0400
From:   Chuck Lever <chuck.lever@...cle.com>
To:     linux-nfs@...r.kernel.org, netdev@...r.kernel.org
Cc:     david@...morbit.com, jlayton@...hat.com, tgraf@...g.ch
Subject: [PATCH v3 31/32] NFSD: NFSv4 CLOSE should release an nfsd_file
 immediately

The last close of a file should enable other accessors to open and
use that file immediately. Leaving the file open in the filecache
prevents other users from accessing that file until the filecache
garbage-collects the file -- sometimes that takes several seconds.

Reported-by: Wang Yugui <wangyugui@...-tech.com>
Link: https://bugzilla.linux-nfs.org/show_bug.cgi?387
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
---
 fs/nfsd/filecache.c |   18 ++++++++++++++++++
 fs/nfsd/filecache.h |    1 +
 fs/nfsd/nfs4state.c |    4 ++--
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index a904364551e8..36d61012d5de 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -458,6 +458,24 @@ nfsd_file_put(struct nfsd_file *nf)
 		nfsd_file_put_noref(nf);
 }
 
+/**
+ * nfsd_file_close - Close an nfsd_file
+ * @nf: nfsd_file to close
+ *
+ * If this is the final reference for @nf, free it immediately.
+ * This reflects an on-the-wire CLOSE or DELEGRETURN into the
+ * VFS and exported filesystem.
+ */
+void nfsd_file_close(struct nfsd_file *nf)
+{
+	nfsd_file_put(nf);
+	if (refcount_dec_if_one(&nf->nf_ref)) {
+		nfsd_file_unhash(nf);
+		nfsd_file_lru_remove(nf);
+		nfsd_file_free(nf);
+	}
+}
+
 struct nfsd_file *
 nfsd_file_get(struct nfsd_file *nf)
 {
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 7b40d5b446e1..c5ddc877116b 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -54,6 +54,7 @@ void nfsd_file_cache_shutdown(void);
 int nfsd_file_cache_start_net(struct net *net);
 void nfsd_file_cache_shutdown_net(struct net *net);
 void nfsd_file_put(struct nfsd_file *nf);
+void nfsd_file_close(struct nfsd_file *nf);
 struct nfsd_file *nfsd_file_get(struct nfsd_file *nf);
 void nfsd_file_close_inode_sync(struct inode *inode);
 bool nfsd_file_is_cached(struct inode *inode);
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3a05c095dfe5..9d1a3e131c49 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -820,9 +820,9 @@ static void __nfs4_file_put_access(struct nfs4_file *fp, int oflag)
 			swap(f2, fp->fi_fds[O_RDWR]);
 		spin_unlock(&fp->fi_lock);
 		if (f1)
-			nfsd_file_put(f1);
+			nfsd_file_close(f1);
 		if (f2)
-			nfsd_file_put(f2);
+			nfsd_file_close(f2);
 	}
 }