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 BC05F1E3DDE for ; Thu, 4 Jun 2026 20:24:06 +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=1780604648; cv=none; b=fv9iIRQSrOvfHhZ8SwxhYdDBnGhUHLFLQtbVmHgp+/Ewc2UFww8r3z6DIzOfw/YcCQMBmlThBJO7LKQr+EBdig6Spf594Hol+u7xzEa61MyzSdowUGOsYOB93GeZ+QHwLbq5EcuZIWO/FdRIEyDHIYv+vmmGSH0HlTSPoLUBzWY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780604648; c=relaxed/simple; bh=f63D5BSJuB1/MEKSMk9cJnKPSIaWN+wb0wCyIwyVgx4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HC1wlw4j0PUhqjpQWSyUDHhP4hZJM6RQjRh1qH9xvjB1+9SQ0HjSBpkcYmQdHjHkHmHLb1y1h5AQeUPk5fpYKWbu10OdDyW6tPty1mLFhv1vcBHG59f2MWwcJDBVPzdqGwG8UceUmm+uTwWDiGtcol//azm7uqnnNlW1LpeCYB0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iXOgZxBv; 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="iXOgZxBv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4189F1F00898; Thu, 4 Jun 2026 20:24:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780604646; bh=C2UtE/UCemdPFjKl1HBzD/U4exwCIXDo7dUHWlbHTNk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iXOgZxBvhnxyMzyvc07HTFGaTQYG0JICgL5tlySndLcj2FmstK32IRpNUJqfZQq8n xOnn0dN9vr7b6GIFrVgupteMARsdgVxze+zZ0aqbPJj3RY50ympx018YAHTNgCk9KM +hdeyJOCTmFdDA53S84CXEKcu7yDizCJ3KWgV7tsWlKqb4BkhBhNWU+bh78uwA/Nax OhIFYvis3pAEP7klawAVkzI3dprr45gaKn1SiBMKzDKEhG+LHyA5yNS+vtDnZVeJpc 2e01bk12UnhIXCn9mcV3AB7xq6NxZsmdeQNu3A5GxZ8pA1fDb3l3kX27z+NrH05cr4 cEQhDnohALJ+w== From: Mike Snitzer To: Trond Myklebust , Anna Schumaker Cc: linux-nfs@vger.kernel.org Subject: [PATCH 1/2] NFSv4/flexfiles: honor FF_FLAGS_NO_IO_THRU_MDS on fatal DS connect errors Date: Thu, 4 Jun 2026 16:24:02 -0400 Message-ID: <20260604202403.20856-2-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20260604202403.20856-1-snitzer@kernel.org> References: <20260604202403.20856-1-snitzer@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 Commit f06bedfa62d5 ("pNFS/flexfiles: don't attempt pnfs on fatal DS errors") teaches ff_layout_{read,write}_pagelist() to return PNFS_NOT_ATTEMPTED when nfs4_ff_layout_prepare_ds() fails with a nfs_error_is_fatal() errno (e.g. -ETIMEDOUT from a SOFTCONN connect deadline, -ENOMEM, -ERESTARTSYS), so that the client gives up instead of spinning. pnfs_do_{read,write}() then dispatches the I/O through pnfs_{read,write}_through_mds() → nfs_pageio_reset_{read,write}_mds(). That fallback is unconditional and silently violates FF_FLAGS_NO_IO_THRU_MDS: when the layout segment carries the flag (typically single-mirror appliance layouts where MDS I/O is explicitly forbidden), the out_failed: path's \`&& !ds_fatal_error\` clause overrides the flag's short-circuit through ff_layout_avoid_mds_available_ds() and routes the I/O to the MDS file handle anyway. This is reachable in practice during a data-server restart: SOFTCONN exhaustion produces -ETIMEDOUT, which is fatal per nfs_error_is_fatal(), which triggers PNFS_NOT_ATTEMPTED, which silently goes to MDS. Preserve the upstream "don't spin on fatal errors" intent for layouts that permit MDS fallback. For layouts with FF_FLAGS_NO_IO_THRU_MDS set, mark the layout for return and request PNFS_TRY_AGAIN instead; if the server cannot supply a usable layout the failure now surfaces cleanly via pnfs_update_layout(), rather than via silent MDS I/O that contradicts the flag. Fixes: f06bedfa62d5 ("pNFS/flexfiles: don't attempt pnfs on fatal DS errors") Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Mike Snitzer --- fs/nfs/flexfilelayout/flexfilelayout.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index 4d142f1fdf61a..38bcd260e0a91 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -2204,6 +2204,14 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr) out_failed: if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error) return PNFS_TRY_AGAIN; + if (ff_layout_no_fallback_to_mds(lseg)) { + /* + * FF_FLAGS_NO_IO_THRU_MDS: force fresh LAYOUTGET, + * never fall through to MDS I/O. + */ + pnfs_error_mark_layout_for_return(hdr->inode, lseg); + return PNFS_TRY_AGAIN; + } trace_pnfs_mds_fallback_read_pagelist(hdr->inode, hdr->args.offset, hdr->args.count, IOMODE_READ, NFS_I(hdr->inode)->layout, lseg); @@ -2289,6 +2297,14 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync) out_failed: if (ff_layout_avoid_mds_available_ds(lseg) && !ds_fatal_error) return PNFS_TRY_AGAIN; + if (ff_layout_no_fallback_to_mds(lseg)) { + /* + * FF_FLAGS_NO_IO_THRU_MDS: force fresh LAYOUTGET, + * never fall through to MDS I/O. + */ + pnfs_error_mark_layout_for_return(hdr->inode, lseg); + return PNFS_TRY_AGAIN; + } trace_pnfs_mds_fallback_write_pagelist(hdr->inode, hdr->args.offset, hdr->args.count, IOMODE_RW, NFS_I(hdr->inode)->layout, lseg); -- 2.44.0