From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 BF4DE48124A for ; Tue, 28 Apr 2026 13:20:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777382402; cv=none; b=ECoed0AbbC6v30OUYjop7iiF39uEVNJI/hZwEUMc9BLCzoN/7pDaRIPbRUG/Aj9HgfzAy41zxYQR3brk0bvsTVjF0R/RW/rQjM7YbTrjmgTSvuOoC1a+/6spREQdZJqSuG4ElvKiBhmkpc1oW98x2RqXUP5EW0N5WSI/hyv96G4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777382402; c=relaxed/simple; bh=hhlZHzVkZGgNw65TAqSXoZn8aY9+h0Opjd6qveHBrl8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AWnkgwCy0OXUh0f6vfvj82a7e0Qj+enOznIl+8uEYvwB1T1x0MKFZeOEGQiNcAeuAeMV1PiLCLMYgSvh9wQCgKGqj4D0Be9kQrriRzJhDMmlqbtlvfnzWbeu0mEO/ipl1u8cD8eZiKkL8/NaeaUoOZmZCCQhIGHcZNS38Yh65Ks= 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=fQX5rp4b; arc=none smtp.client-ip=170.10.133.124 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="fQX5rp4b" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777382400; 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=mt629XDWKB+tZOOSAJE2LdFWKC9Q9poIqsffgDORXAw=; b=fQX5rp4b4y//9xNTLe4kit+WBaYQ5aHWbVWGBHoqwAGMSYND+vg63xYkuxw4Q60HYfvjpQ /MvXva9NPw+uJiPkEGxkVMyv9wl7o/4DvXupiSFesAfoCcBnIlD7wcDSTuIQGWhs6hfy70 BwW9VKsjFvTNvnCvowfZ4mX1zdT5krs= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-474-3o6WZebRMVq1RarP7C2BZg-1; Tue, 28 Apr 2026 09:19:54 -0400 X-MC-Unique: 3o6WZebRMVq1RarP7C2BZg-1 X-Mimecast-MFC-AGG-ID: 3o6WZebRMVq1RarP7C2BZg_1777382393 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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 03053195605B; Tue, 28 Apr 2026 13:19:53 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.44.32.126]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1473F180047F; Tue, 28 Apr 2026 13:19:49 +0000 (UTC) From: David Howells To: Christian Brauner Cc: David Howells , Paulo Alcantara , 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, Marc Dionne Subject: [PATCH v5 23/24] netfs, afs: Fix write skipping in dir/link writepages Date: Tue, 28 Apr 2026 14:17:53 +0100 Message-ID: <20260428131756.922303-24-dhowells@redhat.com> In-Reply-To: <20260428131756.922303-1-dhowells@redhat.com> References: <20260428131756.922303-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@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_write_single() and afs_single_writepages() to better handle a write that would be skipped due to lock contention and WB_SYNC_NONE by returning 1 from netfs_write_single() if it skipped and making afs_single_writepages() skip also. If a skip occurs, the inode must be re-marked as the VFS may have cleared the mark. This is really only theoretical for directories in netfs_write_single() as the only path to that is through afs_single_writepages() that takes the ->validate_lock around it, thereby serialising it. Fixes: 6dd80936618c ("afs: Use netfslib for directories") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org --- fs/afs/dir.c | 11 ++++++++++- fs/netfs/write_issue.c | 7 ++++++- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/afs/dir.c b/fs/afs/dir.c index aaaa55878ffd..d1542a1a50bf 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -2206,7 +2206,14 @@ int afs_single_writepages(struct address_space *mapping, /* Need to lock to prevent the folio queue and folios from being thrown * away. */ - down_read(&dvnode->validate_lock); + if (!down_read_trylock(&dvnode->validate_lock)) { + if (wbc->sync_mode == WB_SYNC_NONE) { + /* The VFS will have undirtied the inode. */ + netfs_single_mark_inode_dirty(&dvnode->netfs.inode); + return 0; + } + down_read(&dvnode->validate_lock); + } if (is_dir ? test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) : @@ -2214,6 +2221,8 @@ int afs_single_writepages(struct address_space *mapping, iov_iter_folio_queue(&iter, ITER_SOURCE, dvnode->directory, 0, 0, i_size_read(&dvnode->netfs.inode)); ret = netfs_writeback_single(mapping, wbc, &iter); + if (ret == 1) + ret = 0; /* Skipped write due to lock conflict. */ } up_read(&dvnode->validate_lock); diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c index 0b07ebecb157..a85ec300b79a 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -823,6 +823,9 @@ static int netfs_write_folio_single(struct netfs_io_request *wreq, * * Write a monolithic, non-pagecache object back to the server and/or * the cache. + * + * Return: 0 if successful; 1 if skipped due to lock conflict and WB_SYNC_NONE; + * or a negative error code. */ int netfs_writeback_single(struct address_space *mapping, struct writeback_control *wbc, @@ -839,8 +842,10 @@ int netfs_writeback_single(struct address_space *mapping, if (!mutex_trylock(&ictx->wb_lock)) { if (wbc->sync_mode == WB_SYNC_NONE) { + /* The VFS will have undirtied the inode. */ + netfs_single_mark_inode_dirty(&ictx->inode); netfs_stat(&netfs_n_wb_lock_skip); - return 0; + return 1; } netfs_stat(&netfs_n_wb_lock_wait); mutex_lock(&ictx->wb_lock);