From nobody Wed Dec 17 03:02:27 2025 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 5830FC54FB9 for ; Fri, 17 Nov 2023 21:19:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346227AbjKQVTN (ORCPT ); Fri, 17 Nov 2023 16:19:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346319AbjKQVSp (ORCPT ); Fri, 17 Nov 2023 16:18:45 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33E952698 for ; Fri, 17 Nov 2023 13:17:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700255868; 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=njtooIaoqHtxOz+7Ms2cQooTNH6njUKNcTP7iunfXh8=; b=jJUp4xZ8u5Zt2GtwF0gvadtL4u+Di7MYsdt7tJvFrS+RZ7vO5GUedSksxf5J9B1e+2gDNr 48Eq9fzmZAkO5YBu0+Lv/1WjFrxQkISVDd2xAxSbKnsrK139b0XDobt3ZGmwohypdy7N1m Qu6PUQ4BpIPLwrowy/dPVA/+OD/YjlA= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-472-1TtKUSzjOcS24bYRIYVe3A-1; Fri, 17 Nov 2023 16:17:44 -0500 X-MC-Unique: 1TtKUSzjOcS24bYRIYVe3A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 457B328040BB; Fri, 17 Nov 2023 21:17:43 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id A789DC15881; Fri, 17 Nov 2023 21:17:40 +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-cachefs@redhat.com, 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 Subject: [PATCH v2 28/51] netfs: Allow buffered shared-writeable mmap through netfs_page_mkwrite() Date: Fri, 17 Nov 2023 21:15:20 +0000 Message-ID: <20231117211544.1740466-29-dhowells@redhat.com> In-Reply-To: <20231117211544.1740466-1-dhowells@redhat.com> References: <20231117211544.1740466-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Provide an entry point to delegate a filesystem's ->page_mkwrite() to. This checks for conflicting writes, then attached any netfs-specific group marking (e.g. ceph snap) to the page to be considered dirty. 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 | 59 +++++++++++++++++++++++++++++++++++++++ include/linux/netfs.h | 4 +++ 2 files changed, 63 insertions(+) diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 60e7da53cbd2..3c1f26f32351 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -413,3 +413,62 @@ ssize_t netfs_file_write_iter(struct kiocb *iocb, stru= ct iov_iter *from) return ret; } EXPORT_SYMBOL(netfs_file_write_iter); + +/* + * Notification that a previously read-only page is about to become writab= le. + * Note that the caller indicates a single page of a multipage folio. + */ +vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *ne= tfs_group) +{ + struct folio *folio =3D page_folio(vmf->page); + struct file *file =3D vmf->vma->vm_file; + struct inode *inode =3D file_inode(file); + vm_fault_t ret =3D VM_FAULT_RETRY; + int err; + + _enter("%lx", folio->index); + + sb_start_pagefault(inode->i_sb); + + if (folio_wait_writeback_killable(folio)) + goto out; + + if (folio_lock_killable(folio) < 0) + goto out; + + /* Can we see a streaming write here? */ + if (WARN_ON(!folio_test_uptodate(folio))) { + ret =3D VM_FAULT_SIGBUS | VM_FAULT_LOCKED; + goto out; + } + + if (netfs_folio_group(folio) !=3D netfs_group) { + folio_unlock(folio); + err =3D filemap_fdatawait_range(inode->i_mapping, + folio_pos(folio), + folio_pos(folio) + folio_size(folio)); + switch (err) { + case 0: + ret =3D VM_FAULT_RETRY; + goto out; + case -ENOMEM: + ret =3D VM_FAULT_OOM; + goto out; + default: + ret =3D VM_FAULT_SIGBUS; + goto out; + } + } + + if (folio_test_dirty(folio)) + trace_netfs_folio(folio, netfs_folio_trace_mkwrite_plus); + else + trace_netfs_folio(folio, netfs_folio_trace_mkwrite); + netfs_set_group(folio, netfs_group); + file_update_time(file); + ret =3D VM_FAULT_LOCKED; +out: + sb_end_pagefault(inode->i_sb); + return ret; +} +EXPORT_SYMBOL(netfs_page_mkwrite); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 4cdadd1ce328..80e48af8b72f 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -404,6 +404,10 @@ int netfs_write_begin(struct netfs_inode *, struct fil= e *, void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t len= gth); bool netfs_release_folio(struct folio *folio, gfp_t gfp); =20 +/* VMA operations API. */ +vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *ne= tfs_group); + +/* (Sub)request management API. */ void netfs_subreq_terminated(struct netfs_io_subrequest *, ssize_t, bool); void netfs_get_subrequest(struct netfs_io_subrequest *subreq, enum netfs_sreq_ref_trace what);