From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 CBA67389471 for ; Thu, 25 Jun 2026 14:08:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782396502; cv=none; b=bBHqOcn2sbObs0/CpjiWYFb7QODXKzXu+Eq8q0IkgPSbQSk0KCQ1SfW1C/d13REEA6ipMf4+vy9BFOlI84HYCZdZmTseF0rlxufGCyyESBOunsI/gK4HydIAaYpnREvPYjhAXMmzWuWR+ABmoV8RtRlcj7vvnFkslxjjn4BOMTo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782396502; c=relaxed/simple; bh=J7N3LfaCZEl3u7MqmzlDY25hDe3GHF6ZhPA2zYyXLJM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ezFpXLGPtaa9HVw1Q3j+Rav41/KTdrtCc0WBhGFxhAMF5iqLrGcHkuS7H4WZvbnvA3l6hXqaQ9iWsoYRmpjOSNiHYf/QFtgTJrV5AQ+uKsUoiv77X0rYKEDkqnDbeu2WpFEHG7T1c19nNj3wfB7xZXhw6qyVzixRb3di6NvVitw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=eRNhhDOM; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eRNhhDOM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782396500; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8eQpn2DxVVlAysyqP0fiZy6BHi38PFlf6WR7Omr8vFE=; b=eRNhhDOMeuMsKkvfmB+cssUdgPcQ+THA13SIv10bhkUKVKiF3Ui43XxhZT3wpI0yPyslrY yHLHJqjgKgOBk3CzbacJ6hk3VHfktfTgHNHPRJje8kp5lXjpjrpKz+yReoJDREJQlQsZPx Pe0CD5FN/8pLfQqBif8p6Xru1/fS5NM= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-221-fNE8G0NGNp-PiX8MnKgxCg-1; Thu, 25 Jun 2026 10:08:15 -0400 X-MC-Unique: fNE8G0NGNp-PiX8MnKgxCg-1 X-Mimecast-MFC-AGG-ID: fNE8G0NGNp-PiX8MnKgxCg_1782396493 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BF40918A0E0D; Thu, 25 Jun 2026 14:08:12 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.44.49.152]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E58FD180059F; Thu, 25 Jun 2026 14:08:08 +0000 (UTC) From: David Howells To: Christian Brauner Cc: David Howells , Paulo Alcantara , Christoph Hellwig , netfs@lists.linux.dev, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+3c74b1f0c372e98efc32@syzkaller.appspotmail.com, hongao , ChenXiaoSong Subject: [PATCH v3 15/15] netfs: Fix DIO write retry for filesystems without a ->prepare_write() Date: Thu, 25 Jun 2026 15:06:33 +0100 Message-ID: <20260625140640.3116900-16-dhowells@redhat.com> In-Reply-To: <20260625140640.3116900-1-dhowells@redhat.com> References: <20260625140640.3116900-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Fix netfs_unbuffered_write() so that it doesn't re-issue a write twice when the filesystem doesn't have a ->prepare_write(). The resetting of the iterator and the call to netfs_reissue_write() should just be removed as almost everything it does is done again when the loop it's in goes back to the top. It does, however, still need the IN_PROGRESS flag setting, so that (and the stat inc) are moved out of the if-statement. Further, the MADE_PROGRESS flags should be cleared and wreq->transferred should be updated, so fix those too. Reported-by: syzbot+3c74b1f0c372e98efc32@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3c74b1f0c372e98efc32 Signed-off-by: David Howells cc: Paulo Alcantara cc: hongao cc: ChenXiaoSong cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/netfs/direct_write.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c index 25f8ceb15fad..c16fbad286a1 100644 --- a/fs/netfs/direct_write.c +++ b/fs/netfs/direct_write.c @@ -166,13 +166,16 @@ static int netfs_unbuffered_write(struct netfs_io_request *wreq) */ subreq->error = -EAGAIN; trace_netfs_sreq(subreq, netfs_sreq_trace_retry); - if (subreq->transferred > 0) + if (subreq->transferred > 0) { iov_iter_advance(&wreq->buffer.iter, subreq->transferred); + wreq->transferred += subreq->transferred; + } if (stream->source == NETFS_UPLOAD_TO_SERVER && wreq->netfs_ops->retry_request) wreq->netfs_ops->retry_request(wreq, stream); + __clear_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags); __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags); __clear_bit(NETFS_SREQ_BOUNDARY, &subreq->flags); __clear_bit(NETFS_SREQ_FAILED, &subreq->flags); @@ -186,17 +189,10 @@ static int netfs_unbuffered_write(struct netfs_io_request *wreq) netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); - if (stream->prepare_write) { + if (stream->prepare_write) stream->prepare_write(subreq); - __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags); - netfs_stat(&netfs_n_wh_retry_write_subreq); - } else { - struct iov_iter source; - - netfs_reset_iter(subreq); - source = subreq->io_iter; - netfs_reissue_write(stream, subreq, &source); - } + __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags); + netfs_stat(&netfs_n_wh_retry_write_subreq); } netfs_unbuffered_write_done(wreq);