From nobody Sun May 24 19:35:53 2026 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 4276040963B; Fri, 22 May 2026 16:44:23 +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=1779468265; cv=none; b=GZbRXpDjdkI37VpfZ5PTiC7gAa3bnFTQvAjyLsWUYJ7VGNXgc7SDbBC5CqCVdmwmKLrO8WvG8iCzUb6U0mX6sFNxWVkEJDK/xkEJIV4B9GFqAOB5tgzHFDrj9TN10133A9vrcpOuptLFqFFmERWNsTC5VaGwFoYMkIo65UcD03Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779468265; c=relaxed/simple; bh=weTvBs1MjU+aC8Cdqkl6LwmSWO3h+MHoIDx9hJ6G68U=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=DM6Hhvmt6SKBGNnIWI+00ejxnwJANgSCc3yQMcyDLr9iynUZLFiG4RoJ+zyjaVb8qad34qk3vJE5X8ebfIRP2vY5pEqvMdn0cMYWmZ22jawsnr/tCRHK9kFUoHUF7OMdGhsKGzCSv9JcqUJhbTKlJaOJuNpunqZ6MGePGKLUGtk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P/hyr3eJ; 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="P/hyr3eJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0183E1F00A3D; Fri, 22 May 2026 16:44:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779468263; bh=gu5wLq9eA0hzzZ217be+ZqxxCAWuDHV5yrh5Ki1KnbY=; h=From:Date:Subject:To:Cc; b=P/hyr3eJgc1k1xl5tvz8xpHEziO8Xcw81HJtYP7+wYVZhvhnp1ypj345e6SIY9Lqe bnTYk8CcXnIYGrOhxSjQ+G2OkG5gbfH2cHetv3L7LYCo5bP1Af4AswI2EuJlONpqBz qT0shV7pBcF+oG3YZ/gthZR3k80H2Xta6vRlofYKP0hvuf0yRnfHURT7biKFDgWUsS EZI/K8xii1fB8gbh+iTcSOXktM7FTDsGdd45mSdqevog/dfONapWMF2THXvVTRCxpv vvgZTPm/dW++xJwpPTvIjKDLLz6QyC+ePglWqnqsvPRetmvMnaQQM1Hpie2WL+gwXe InZHd5c4Q36XQ== From: Jeff Layton Date: Fri, 22 May 2026 12:44:19 -0400 Subject: [PATCH] nfsd: reset write verifier on deferred writeback errors Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260522-missing_verifier_reset_on_wb_err-v1-1-bf9f427f9b26@kernel.org> X-B4-Tracking: v=1; b=H4sIAAAAAAAC/x2NwQqDMBAFf0X2bCANqYi/ImUx9Wn3YCy7ogXx3 xs8zmFmTjKowKirTlLsYrLmAo+6ovdnyDOcjIUp+ND4ZwhuETPJM+/FmwTKCsPGa+YjMVRdbD1 SE4eIBCqZr2KS373oX9f1B34r9x9yAAAA X-Change-ID: 20260522-missing_verifier_reset_on_wb_err-480eb64a4ebe To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Chris Mason , Jeff Layton X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=2202; i=jlayton@kernel.org; h=from:subject:message-id; bh=weTvBs1MjU+aC8Cdqkl6LwmSWO3h+MHoIDx9hJ6G68U=; b=owEBbQKS/ZANAwAKAQAOaEEZVoIVAcsmYgBqEIfmT4qidPuF8ByAne8hxFlsQQ7JEZ//9c5vn YhUdYs+nWCJAjMEAAEKAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCahCH5gAKCRAADmhBGVaC FU/VEACMXNVKmK9t0uc1V5+1G0XfPOHVD7hrYQc2O/XrDYDhIoJbzftdE3hdOjTByiqZNHGC4Lg dPN+V5RnKtaH8YIRQ1Bt/tBKOSWsQn6Z0I0EM2nreu0v+nt8HGtXAJKU4ogfVVOlFG7ux6+X7cd G1Hz9/53tPwXP+Pe77H63cQv0ULgqIzXsTstvQKZGu/FxihTYn91AhaxcRVSNi/A6Qo7q1dGtlO caZCluA9xIky240kn2mhHl7CA57NniFOaIgWYM0TLw63tyGgOyuQo3XL53LVoVvDGkoIdlRt6MC EHb5ZqD2MhviS8GtAvMgFlw0l3/0y7jLXveYJ1STWognq8ZaMYv+efbCeycwKUV/E4mWsJ0pICl XiXgVLFqY2OIvugrqZHl49XjRElq0NDggcmOaBeYtNYfyLV/g18F437pWVFktA+Xb+sesMcKmZF OG6YK/Tk5st322x7EcRVDx/ke0Q5Lq2tHdTNRig2HbZnZhrB9epZM0wpmEYHiFPk7+g1lHeLwaU C2AlU2zAkuh+7uK3b3Anou/LFpdSayJx3kuEz5nS+d0rsKOrkdRVsBcQlGY6iGQWfxqZlZScGaN pTvVCWqPN3K9wEBR4kUM50XuSSAV+iW4i10kO1rqVgywiRMdJuwcS7DkprVrQpw6B7komT16nJl M8Mt2+28S3I1HdA== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 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 =E2=80=94 silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 =C2=A73.3.7, RFC 8881 =C2=A718.32). 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 Assisted-by: kres:claude-opus-4-6 Signed-off-by: Jeff Layton --- fs/nfsd/vfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index cba473969429..7e6468bdc723 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1513,8 +1513,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh= *fhp, nfsd_stats_io_write_add(nn, exp, *cnt); fsnotify_modify(file); host_err =3D 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; + } =20 if (stable && fhp->fh_use_wgather) { host_err =3D wait_for_concurrent_writes(file); @@ -1694,6 +1696,8 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fh= p, struct nfsd_file *nf, nfsd_copy_write_verifier(verf, nn); err2 =3D filemap_check_wb_err(nf->nf_file->f_mapping, since); + if (err2 < 0) + commit_reset_write_verifier(nn, rqstp, err2); err =3D nfserrno(err2); break; case -EINVAL: --- base-commit: 6167e81847ba3adca17d8881ed9415beae993e2d change-id: 20260522-missing_verifier_reset_on_wb_err-480eb64a4ebe Best regards, --=20 Jeff Layton