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 A7B3D312834; Thu, 2 Jul 2026 21:41:38 +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=1783028499; cv=none; b=WHMehhJ9x9+QJBVxhjpk0iGtATQpjZQdsxD5pNg/gBjENnVTWFN1zYR0IKX6xBtvkFadMiExhCvLJrZkiA4KgSdiGaTmS0eI1VMeIYsG5JYMYd+RMuTMiUGbTxiFi7pZCX+L8X9NtbV2xIB8ukbXtDYI1tNy4acvU5fgj6+1L0k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783028499; c=relaxed/simple; bh=tT/3omg3PNgIoOIavzQkCy5itycSAAr2+yb/AXr4bSU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=RcIe+TGSCzOeSpZEZpggEneN9kRJcr6Gm0M3nYCnNzmrdxgupSHr/iZ03bkUjwWER+PchtKetoHq8x1aWcvTYg+Z8nF7aPrjUs1v4IbtlRng8+srv/Avvs3eRm98eT1SG2TkWP22dybNkrS9M1Xp3h86I9RhAXmcOBvxuVmPue0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=C1nmlsUK; 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="C1nmlsUK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27A951F00A3D; Thu, 2 Jul 2026 21:41:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783028498; bh=D0+XDJ0DE8l6O8P0lzGa5SSgmMFTY4bNO+D7PkidL6Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=C1nmlsUKN46VHIwEmYuqu3Jl0dnrNR8rgh0agHtBrr6mGwEOq0NyVrPWP1PXsxfMj XEB+dZ0vBwRMOzPICy+02qlePQ6qa9uzlAVe5rCVZTxsZhkpmGQUqOS3tZSjCMACvc lvQwq9gpGxJ17eyILgagegP1alDY3DxqQM+u3dxhfF9lj+oJ042+wOruRM1k+Morjw oOzhiRsguWHlljZhT5ZTfDfIBoGypu4GlWldb3k0+o1RlfXYR1fBml2lw3icjHo+/N tlmkTIJQbRzQ2+zq7mOlDlYCGN4AhYkh4+6HnPgl5tDEFx1hWQL9BTYDpVZbpY1PlO dCvmSAUqoif0A== From: Chuck Lever To: Cc: , Jeff Layton , Chris Mason Subject: [PATCH 6.6.y 2/2] nfsd: reset write verifier on deferred writeback errors Date: Thu, 2 Jul 2026 17:41:35 -0400 Message-ID: <20260702214135.533354-2-cel@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260702214135.533354-1-cel@kernel.org> References: <20260702214135.533354-1-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: 6.6.y predates the commit_reset_write_verifier() helper (v6.7); open-coded nfsd_reset_write_verifier() and the reset tracepoint at both sites, matching the other reset paths in these functions ] 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 ae1f43eb515a..6658c92340f2 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1185,8 +1185,11 @@ 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); @@ -1330,6 +1333,10 @@ 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