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 974253148DA; Fri, 3 Jul 2026 03:32:50 +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=1783049580; cv=none; b=qCrGK+SWx9SV0xB8Rwge7HSUumn6HgFKwroh1BuIS1Sk7tFIpxPTNfU0kRUNlXLEnwADI5uF+zj62NwJNBjjKO3IHVTGzzt/EZaJd9xnetqN6j7JoXfsL75Lt1htHEqyv9+tyDhPfyvXrWovSp4bEyfnOSTGsIEWNDJI6vriPbg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783049580; c=relaxed/simple; bh=UyVKHl44V9oblhGbFz3Nt2ly+SeUjgUCGBMkhPzd/yo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EdtozdG9S3SAhuGVgDa0sTUDDr7mLaYAo0ovHeiMTp4oefi24b4aZIaYsiF0WtHh3sp0t950WU4TFMfNoLz3Ow0YgWDthYwcWZKtg4LST0oDyD51kEQ1ELxnU0UB77tJgCJye9IdpN8aiqBazrDpu0zUWN5tj//y36+p8OFpk5o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WvEGIbeu; 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="WvEGIbeu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B45281F00A3A; Fri, 3 Jul 2026 03:32:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783049567; bh=l5TPp3rc00ZF15B3XLumzanSxaqs36Mi+WEr8CXXg6I=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WvEGIbeu6I519kOOSH7q9qsLcEVT04XYa8ISPefpWFT8BzqyIqgUnNFaa3O1cYr9W Ab1/5+8JJX6rqTR1cwflU/FFgpN/o1CUgfWdqi5Dq/On0YSRKOQJYoHRKcbC9KpxhU EH29euyWxsFQ8vxD0P++goB13CuV1XWQicbz4BUZhB1WRKBJ0DpPnRVKZkQ5xCCTXE IgcgQgUNe7dCPiIYhrSZE0/44Jv0T1YTfLNyPYAjM8ZhqUY1krC30VqWkZgOiRo+AW 6l23I68DdeNOkcisNfAwj26s6QyrLTeWsyCYKR8Bxq9xKVCalauthD+gdQethchvcN /6kMPKQcMXh3A== From: Chuck Lever To: Cc: , Jeff Layton , Chris Mason Subject: [PATCH 6.1.y 2/2] nfsd: reset write verifier on deferred writeback errors Date: Thu, 2 Jul 2026 23:32:43 -0400 Message-ID: <20260703033243.1539871-2-cel@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260703033243.1539871-1-cel@kernel.org> References: <20260703033243.1539871-1-cel@kernel.org> 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 87a596fc6654..c40b2a706691 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1134,8 +1134,11 @@ 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); @@ -1271,6 +1274,10 @@ 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