From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3BDFB42046; Mon, 8 Apr 2024 13:55:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712584501; cv=none; b=vAIRB6uCy6VXVhjrjRJspPOmWk/+NmR7t7WAD8D4xUVQnNugJMYwdnmYWJISC5+X5C9SKeUnBJz6Jn2fzLXGjiicreyTI4tl9AlsRvBYogFLIFlLEmobkUuh3bxgYZip5EUnulxLKZsX0KNjGOlRYHp2KwAaKuiGSPWz5nLxLVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712584501; c=relaxed/simple; bh=XcLawigW5NARb7ki/Nd/3pOkD/lilKPCz8okykQ9+EQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H+KZv1jkKPIrYn/KH+67XwHNTf57VvsHQ0f3MomJzOlNt956ilgyLcpxQJ7bMJNACJ4cbh2Mp5eWCp6/tOsqbmRbWsvK/s4j7g1p3lVWkrE51QGtTBiRUQdkgG6eTHRakjxDJhb7+1LoF8YzVNAM8xVjZGfZNf0nW2urarmiLI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QQgZoxl1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="QQgZoxl1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F03AC433F1; Mon, 8 Apr 2024 13:55:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712584501; bh=XcLawigW5NARb7ki/Nd/3pOkD/lilKPCz8okykQ9+EQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QQgZoxl1gBVOUbE5eHEZo5ULPf+C4d/R5Au1oA6Cy4CkAZrhHvglrgKMm2jzQfRYb Z+WoUkTNx9hbMb+xduvu4Wmc8AY8dtQc6UJn3/8XFgHH9y9tzq2u5Bl0odCEuT4p7W iX42t8FQCV0vLAethGAItVtjp5LTRXeV2CsrwwBs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeff Layton , Chuck Lever Subject: [PATCH 5.15 460/690] nfsd: rework hashtable handling in nfsd_do_file_acquire Date: Mon, 8 Apr 2024 14:55:26 +0200 Message-ID: <20240408125416.283064114@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240408125359.506372836@linuxfoundation.org> References: <20240408125359.506372836@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton [ Upstream commit 243a5263014a30436c93ed3f1f864c1da845455e ] nfsd_file is RCU-freed, so we need to hold the rcu_read_lock long enough to get a reference after finding it in the hash. Take the rcu_read_lock() and call rhashtable_lookup directly. Switch to using rhashtable_lookup_insert_key as well, and use the usual retry mechanism if we hit an -EEXIST. Rename the "retry" bool to open_retry, and eliminiate the insert_err goto target. Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever --- fs/nfsd/filecache.c | 52 +++++++++++++++++++-------------------------- 1 file changed, 22 insertions(+), 30 deletions(-) diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index a0d93e797cdce..0b19eb015c6c8 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -1041,9 +1041,10 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, .need = may_flags & NFSD_FILE_MAY_MASK, .net = SVC_NET(rqstp), }; - struct nfsd_file *nf, *new; - bool retry = true; + bool open_retry = true; + struct nfsd_file *nf; __be32 status; + int ret; status = fh_verify(rqstp, fhp, S_IFREG, may_flags|NFSD_MAY_OWNER_OVERRIDE); @@ -1053,35 +1054,33 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, key.cred = get_current_cred(); retry: - /* Avoid allocation if the item is already in cache */ - nf = rhashtable_lookup_fast(&nfsd_file_rhash_tbl, &key, - nfsd_file_rhash_params); + rcu_read_lock(); + nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key, + nfsd_file_rhash_params); if (nf) nf = nfsd_file_get(nf); + rcu_read_unlock(); if (nf) goto wait_for_construction; - new = nfsd_file_alloc(&key, may_flags); - if (!new) { + nf = nfsd_file_alloc(&key, may_flags); + if (!nf) { status = nfserr_jukebox; goto out_status; } - nf = rhashtable_lookup_get_insert_key(&nfsd_file_rhash_tbl, - &key, &new->nf_rhash, - nfsd_file_rhash_params); - if (!nf) { - nf = new; - goto open_file; - } - if (IS_ERR(nf)) - goto insert_err; - nf = nfsd_file_get(nf); - if (nf == NULL) { - nf = new; + ret = rhashtable_lookup_insert_key(&nfsd_file_rhash_tbl, + &key, &nf->nf_rhash, + nfsd_file_rhash_params); + if (likely(ret == 0)) goto open_file; - } - nfsd_file_slab_free(&new->nf_rcu); + + nfsd_file_slab_free(&nf->nf_rcu); + if (ret == -EEXIST) + goto retry; + trace_nfsd_file_insert_err(rqstp, key.inode, may_flags, ret); + status = nfserr_jukebox; + goto out_status; wait_for_construction: wait_on_bit(&nf->nf_flags, NFSD_FILE_PENDING, TASK_UNINTERRUPTIBLE); @@ -1089,11 +1088,11 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, /* Did construction of this file fail? */ if (!test_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { trace_nfsd_file_cons_err(rqstp, key.inode, may_flags, nf); - if (!retry) { + if (!open_retry) { status = nfserr_jukebox; goto out; } - retry = false; + open_retry = false; nfsd_file_put_noref(nf); goto retry; } @@ -1141,13 +1140,6 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp, smp_mb__after_atomic(); wake_up_bit(&nf->nf_flags, NFSD_FILE_PENDING); goto out; - -insert_err: - nfsd_file_slab_free(&new->nf_rcu); - trace_nfsd_file_insert_err(rqstp, key.inode, may_flags, PTR_ERR(nf)); - nf = NULL; - status = nfserr_jukebox; - goto out_status; } /** -- 2.43.0