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 6D5433093DD; Thu, 2 Jul 2026 16:57:26 +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=1783011447; cv=none; b=tNL1GOChK5UhtQnC5CmGUZVset1soZBoNCZ5kGOin4Wp9vBtgqEEzIjKVi69/QwHH3NUTYlQbwNozKmdFExC2kCV8yBBmEbqRmbRNFqKmK2ewsRbEup1J2tnYvxRbNqOochHXqu6N+9qA982x3px/PrxGgFnpeLOmX9EAkSXeT4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783011447; c=relaxed/simple; bh=JWLTWmk2xzpIblbjaUROqmyz1qT0Bq50dJCEEAuNdrY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kmC5CjvtYgHV72MDdtw386WKu4/0zI8ANm05BnHd7ehWLqtXa2FAA6DGq4sEe+G2jcf39syScLJcJBYL7fRSv8Uu/kfcOWEt5XvzgdeolcBH/nYKFFuV9RNW7hEryHvRyotigPqfoi3IYg1fIIYZiG2kGPBthYpnBmBHIYIcvJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FmtMafBm; 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="FmtMafBm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2C0B1F000E9; Thu, 2 Jul 2026 16:57:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783011446; bh=UbGWYiFd2aUaSzhUyWpdBi4+S+6oLzsJGrEi7PYC7NI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FmtMafBmp5731ELy4xoUGG8r2kFX3+NLEHK4VGtHczEVOM5SNezVM/wy5I80hU68J JlroQsFBAsm/Oa5e4C5RQFccxavnjRx/g2TbLmIBgEorgW8ihgNuBViJmUxMKhrKoE PHtIzqhIcNIVYKzPyxymYBZqB0fnASBxjbP/vUTY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chris Mason , Jeff Layton , Chuck Lever Subject: [PATCH 6.18 100/108] nfsd: reset write verifier on deferred writeback errors Date: Thu, 2 Jul 2026 18:21:37 +0200 Message-ID: <20260702155114.185190421@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155112.110058792@linuxfoundation.org> References: <20260702155112.110058792@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 6.18-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 Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/vfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1264,8 +1264,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, s 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) { + commit_reset_write_verifier(nn, rqstp, host_err); goto out_nfserr; + } if (stable && fhp->fh_use_wgather) { host_err = wait_for_concurrent_writes(file); @@ -1445,6 +1447,8 @@ nfsd_commit(struct svc_rqst *rqstp, stru nfsd_copy_write_verifier(verf, nn); err2 = filemap_check_wb_err(nf->nf_file->f_mapping, since); + if (err2 < 0) + commit_reset_write_verifier(nn, rqstp, err2); err = nfserrno(err2); break; case -EINVAL: