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 A80F0318146; Fri, 3 Jul 2026 03:37:15 +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=1783049842; cv=none; b=fBRBVoYWTXZjs2T1HNc94bK4Q2oQBcl1tg+uQMKKJdfr1ZmeRqSuktzJdKwwveKYmqMGyV0DGa7LItnCFA5KCYZVqxgUhdEN6ZArecO1IQQKYQKQaQD/QD8E2VuHST+W8I2n0B0j5zzMTlIY+YOGId1V2cQf5R3kakplbWcrcRI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783049842; c=relaxed/simple; bh=uw8dNJSIRwmPU6hOtEiQahKvItGTuZZB1YQm6EBduCg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jL3hbWfoNiVNelmiUapShYcxWvV2l/xX43HgVpnnguIbAzjHdwKykxg7Ttw2IehS1aaThhK8ioDHmNVv0Mx2uLfORfjXwYqjk2PUm2P3ROGh9gjHEYDOTVRItBN2jq6c5zRoUgzznaLAW1Bw4XphYecdL082xZUseFZrBYrFv2w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UGj2kn68; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UGj2kn68" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4106B1F000E9; Fri, 3 Jul 2026 03:37:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783049832; bh=h2gdU2TGu5W6JUdXVgFuxxtiDlZggXXUhPgQZuH1mDk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UGj2kn68+GqrZBevV7VHFoexAaSRizAN3uqVyKbC7ZTXEGxksBGkUvL4SasARkCh9 8asMxIHqQVGP0sCJyMCtevNDQ69+1DefTz+r1QNisDBH9GWyJQB7OyVWbhy6rA3Xwt 3QvI4eJIwrNY8nsaf2jWqJtIF3ToLYNQEGru72ayQq5Milon59IpLzd/Fp44yyJwJH 0p+kHVL3012Jc2s/MvA0TMTlDkgFUSf1KPOjStlBazQW2vi+OZqL8Ju0Ss1YMMpyRK FZXIF0iKDZIgS5YZlUqEpLvuNYy78fK9nYNNAjBWvVn1HdpMAMAGKPXal9nqJMGgNc WIz15MQj8oN9w== From: Chuck Lever To: Cc: , Jeff Layton , Chris Mason Subject: [PATCH 5.15.y] nfsd: reset write verifier on deferred writeback errors Date: Thu, 2 Jul 2026 23:37:05 -0400 Message-ID: <20260703033705.1572486-1-cel@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <2026070204-septum-trimness-cb0f@gregkh> References: <2026070204-septum-trimness-cb0f@gregkh> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- 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 e1737984e0ca..7b0bc4507ad0 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: -- 2.54.0