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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        "J. Bruce Fields" <bfields@redhat.com>
Subject: [PATCH 5.5 191/367] nfsd: fix filecache lookup
Date:   Mon, 10 Feb 2020 04:31:44 -0800
Message-Id: <20200210122442.230279966@linuxfoundation.org>
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From: Trond Myklebust <trondmy@gmail.com>

commit 28c7d86bb6172ffbb1a1237c6388e77f9fe5f181 upstream.

If the lookup keeps finding a nfsd_file with an unhashed open file,
then retry once only.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org
Fixes: 65294c1f2c5e "nfsd: add a new struct file caching facility to nfsd"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfsd/filecache.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -789,6 +789,7 @@ nfsd_file_acquire(struct svc_rqst *rqstp
 	struct nfsd_file *nf, *new;
 	struct inode *inode;
 	unsigned int hashval;
+	bool retry = true;
 
 	/* FIXME: skip this if fh_dentry is already set? */
 	status = fh_verify(rqstp, fhp, S_IFREG,
@@ -824,6 +825,11 @@ wait_for_construction:
 
 	/* Did construction of this file fail? */
 	if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) {
+		if (!retry) {
+			status = nfserr_jukebox;
+			goto out;
+		}
+		retry = false;
 		nfsd_file_put_noref(nf);
 		goto retry;
 	}