linux-kernel - [PATCH 5.4 22/60] nfsd: Dont keep looking up unhashed files in the nfsd file cache

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Message-Id: <20210322121923.111538865@linuxfoundation.org>
Date:   Mon, 22 Mar 2021 13:28:10 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Chuck Lever <chuck.lever@...cle.com>
Subject: [PATCH 5.4 22/60] nfsd: Dont keep looking up unhashed files in the nfsd file cache

From: Trond Myklebust <trond.myklebust@...merspace.com>

commit d30881f573e565ebb5dbb50b31ed6106b5c81328 upstream.

If a file is unhashed, then we're going to reject it anyway and retry,
so make sure we skip it when we're doing the RCU lockless lookup.
This avoids a number of unnecessary nfserr_jukebox returns from
nfsd_file_acquire()

Fixes: 65294c1f2c5e ("nfsd: add a new struct file caching facility to nfsd")
Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/nfsd/filecache.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -751,6 +751,8 @@ nfsd_file_find_locked(struct inode *inod
 			continue;
 		if (!nfsd_match_cred(nf->nf_cred, current_cred()))
 			continue;
+		if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags))
+			continue;
 		if (nfsd_file_get(nf) != NULL)
 			return nf;
 	}