From patchwork Fri Oct 13 16:03:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13421296 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 558E4CDB47E for ; Fri, 13 Oct 2023 16:08:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbjJMQIh (ORCPT ); Fri, 13 Oct 2023 12:08:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56084 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231215AbjJMQIg (ORCPT ); Fri, 13 Oct 2023 12:08:36 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94CFB19B5 for ; Fri, 13 Oct 2023 09:06:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1697213176; 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=fYFiVS0O5EjQomrQ+SnrCnYkLaT5nU/hfhD8w5eAjCY=; b=RxUBM++ukrCtjubiydH412Zn0GcsTcXZgwulda7GhcrNXJ5f+vvEu4R36BgkALf8ZZ/rW3 YOpe1e6waxL0Xg+gKF0uopvZ/uAcTydEtDXyrVRdVcAFJOWju4YPn5LhPoEICZofhs6IE4 K5mIF/Ky86sLnXSQYJqIE/1u074FZvo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-125-53Duo8nMPhGHGtATEeqCAQ-1; Fri, 13 Oct 2023 12:06:09 -0400 X-MC-Unique: 53Duo8nMPhGHGtATEeqCAQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A573F1029F40; Fri, 13 Oct 2023 16:06:08 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 169FB25C0; Fri, 13 Oct 2023 16:06:05 +0000 (UTC) From: David Howells To: Jeff Layton , Steve French Cc: David Howells , Matthew Wilcox , Marc Dionne , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Dominique Martinet , Ilya Dryomov , Christian Brauner , linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-cachefs@redhat.com Subject: [RFC PATCH 29/53] netfs: Implement buffered write API Date: Fri, 13 Oct 2023 17:03:58 +0100 Message-ID: <20231013160423.2218093-30-dhowells@redhat.com> In-Reply-To: <20231013160423.2218093-1-dhowells@redhat.com> References: <20231013160423.2218093-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Institute a netfs write helper, netfs_file_write_iter(), to be pointed at by the network filesystem ->write_iter() call. Make it handled buffered writes by calling the previously defined netfs_perform_write() to copy the source data into the pagecache. Signed-off-by: David Howells cc: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_write.c | 83 +++++++++++++++++++++++++++++++++++++++ include/linux/netfs.h | 3 ++ 2 files changed, 86 insertions(+) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 4de6a12149e4..60e7da53cbd2 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -330,3 +330,86 @@ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, goto out; } EXPORT_SYMBOL(netfs_perform_write); + +/** + * netfs_buffered_write_iter_locked - write data to a file + * @iocb: IO state structure (file, offset, etc.) + * @from: iov_iter with data to write + * @netfs_group: Grouping for dirty pages (eg. ceph snaps). + * + * This function does all the work needed for actually writing data to a + * file. It does all basic checks, removes SUID from the file, updates + * modification times and calls proper subroutines depending on whether we + * do direct IO or a standard buffered write. + * + * The caller must hold appropriate locks around this function and have called + * generic_write_checks() already. The caller is also responsible for doing + * any necessary syncing afterwards. + * + * This function does *not* take care of syncing data in case of O_SYNC write. + * A caller has to handle it. This is mainly due to the fact that we want to + * avoid syncing under i_rwsem. + * + * Return: + * * number of bytes written, even for truncated writes + * * negative error code if no data has been written at all + */ +ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from, + struct netfs_group *netfs_group) +{ + struct file *file = iocb->ki_filp; + ssize_t ret; + + trace_netfs_write_iter(iocb, from); + + ret = file_remove_privs(file); + if (ret) + return ret; + + ret = file_update_time(file); + if (ret) + return ret; + + return netfs_perform_write(iocb, from, netfs_group); +} +EXPORT_SYMBOL(netfs_buffered_write_iter_locked); + +/** + * netfs_file_write_iter - write data to a file + * @iocb: IO state structure + * @from: iov_iter with data to write + * + * Perform a write to a file, writing into the pagecache if possible and doing + * an unbuffered write instead if not. + * + * Return: + * * Negative error code if no data has been written at all of + * vfs_fsync_range() failed for a synchronous write + * * Number of bytes written, even for truncated writes + */ +ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct netfs_inode *ictx = netfs_inode(inode); + ssize_t ret; + + _enter("%llx,%zx,%llx", iocb->ki_pos, iov_iter_count(from), i_size_read(inode)); + + if ((iocb->ki_flags & IOCB_DIRECT) || + test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags)) + return netfs_unbuffered_write_iter(iocb, from); + + ret = netfs_start_io_write(inode); + if (ret < 0) + return ret; + + ret = generic_write_checks(iocb, from); + if (ret > 0) + ret = netfs_buffered_write_iter_locked(iocb, from, NULL); + netfs_end_io_write(inode); + if (ret > 0) + ret = generic_write_sync(iocb, ret); + return ret; +} +EXPORT_SYMBOL(netfs_file_write_iter); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 052d62625796..d1dc7ba62f17 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -388,7 +388,10 @@ ssize_t netfs_unbuffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); /* High-level write API */ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, struct netfs_group *netfs_group); +ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from, + struct netfs_group *netfs_group); ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from); +ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from); /* Address operations API */ struct readahead_control;