From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C283344AB62; Tue, 21 Jul 2026 21:54:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784670890; cv=none; b=p1KlIE5Mvk/Y8jOPW4lRnGqaQP04Z71R185R5YdfboFJhCi9HLs58Pzf1ds2jeLwfYTRs2AlPHJbzTWae6f0onm55ruHn/8gHrxi/8GLjBnNtyGJ7O3rtbQp68MWbnEh0jA69qIy82eviLm1awQJiB1vn9Zca/vqIEQaQMXGCis= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784670890; c=relaxed/simple; bh=A0rwxJe7/QsLSpd/Kn3KzZeN6AvVtZFpnRozhJBwTbA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Yf7dvo8ilxBgeQG5JOqYW2W2lm5bdgq9Qj2+qCmSDLkfGLIlmzc+UvR/k3WACXhyFT1I1w1Qb3LIgrJWoCDv/y2o52yE6kzKpn4VE+Il4o06BBfiIIfNX2i1Y+zcKLGL3q6M2aPv2CxEnnRfmiD8Se8dFgXiLyrCDXJTa9PJtEM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ewb9vzR5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ewb9vzR5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 341771F000E9; Tue, 21 Jul 2026 21:54:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784670889; bh=eMZmJR7J3dCfEmbL8LztjwvKhZr+zzKn7+zPhGkdEBE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ewb9vzR582SnB/yx0yFkFZdRVqLzqYdaiBBIUDPdAuUWBHFlY+b9Lw3Z0jtKvxg4x VSbpQTOVS2BmevsXnkMH8rjPZjQb9ZY8CBF6gDz+BMjNcO4UmOc6iAizbR9KsnupzX 2f0g4uWwzOnygXtpMyL4QQzzEB9MLPJWAbAesHW0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chris Mason , Jeff Layton , Chuck Lever , Chuck Lever , Sasha Levin Subject: [PATCH 5.15 004/843] nfsd: reset write verifier on deferred writeback errors Date: Tue, 21 Jul 2026 17:13:59 +0200 Message-ID: <20260721152406.052270352@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton commit 2090b05803faab8a9fa62fbff871007862cac1b7 upstream. nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the server's write verifier (nn->writeverf) when this check fails. Every other durable-storage-failure path in these functions calls commit_reset_write_verifier() before returning an error. The missing rotation means clients holding UNSTABLE write data under the current verifier will COMMIT, receive the unchanged verifier back, and conclude their data is durable — silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 §3.3.7, RFC 8881 §18.32). Add commit_reset_write_verifier() calls at both filemap_check_wb_err() error sites, matching the pattern used by adjacent error paths in the same functions. The helper already filters -EAGAIN and -ESTALE internally, so the calls are unconditionally safe. Reported-by: Chris Mason Fixes: 555dbf1a9aac ("nfsd: Replace use of rwsem with errseq_t") Cc: stable@vger.kernel.org Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever [ cel: open-code the reset; commit_reset_write_verifier() is v6.7 ] Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/vfs.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index e1737984e0ca11..7b0bc4507ad047 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1133,8 +1133,11 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, nfsd_stats_io_write_add(nn, exp, *cnt); fsnotify_modify(file); host_err = filemap_check_wb_err(file->f_mapping, since); - if (host_err < 0) + if (host_err < 0) { + nfsd_reset_write_verifier(nn); + trace_nfsd_writeverf_reset(nn, rqstp, host_err); goto out_nfserr; + } if (stable && use_wgather) { host_err = wait_for_concurrent_writes(file); @@ -1270,6 +1273,10 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, nfsd_copy_write_verifier(verf, nn); err2 = filemap_check_wb_err(nf->nf_file->f_mapping, since); + if (err2 < 0) { + nfsd_reset_write_verifier(nn); + trace_nfsd_writeverf_reset(nn, rqstp, err2); + } err = nfserrno(err2); break; case -EINVAL: -- 2.53.0