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 6921B3DA5A0 for ; Mon, 27 Apr 2026 15:48:31 +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=1777304912; cv=none; b=S8fPR4Xlb4MpzVc5wtUtc5QgKjAtVRH/VGyCTLiYfelgWx85tKy4W9MkhrFMCgALHuOQkIyfUzBc3WSpmhz0/DGE8XMXswfUlLrZcbrcHZ6Vddh6xg6Mqvm6wjgKv9xn2ggkn2wC9LCAhRKTSf88tqW1zpkRWuR7XfBKWQqHows= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777304912; c=relaxed/simple; bh=c5oDArXQJh7y60M1cLms/vcgi7TX/3O0SYtvfxSNmhk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AcQ/tBylThlFX39NNhc9PoTY8SkaXSLcgmpZjlb8BFmM2+6+sIWzIagwSHr6cxoRc0kYAjKrG36xGIb5NtNbs748+DlD0vEfZQ6F85/7dMwTj5AMsEB2nebnyO0m8PSzt9FNXXdHvGT1GYYFFM6rojXRa2xoM2sgRx52GuTrVPg= 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=MqeXaID7; 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="MqeXaID7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777304910; 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=QS/xrleH5AOpAKSiASxQWMXbrc7cAq+mCszoPIawfWE=; b=MqeXaID7UlsDRDIs4KeWf1gh+XvRp5jgodjkDR8nVbq9dJThM/BgIdHbzLC8HPTDDKh9yu WALYqpHEc7btR0iVCEPR8+s6RylaJEzvOyLZtLZpGnLravANGviNb3foLUJAkmGHmjNLoq /oACKPw0zJQZ9AMJYsNMeDXJP6QqVrs= Received: from mx-prod-mc-05.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-61-BivbckB5P8qzrdjjQiZmnA-1; Mon, 27 Apr 2026 11:48:24 -0400 X-MC-Unique: BivbckB5P8qzrdjjQiZmnA-1 X-Mimecast-MFC-AGG-ID: BivbckB5P8qzrdjjQiZmnA_1777304903 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5A28F19560AF; Mon, 27 Apr 2026 15:48:23 +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 6ADFB1800347; Mon, 27 Apr 2026 15:48:20 +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 v4 21/22] netfs, afs: Fix write skipping in dir/link writepages Date: Mon, 27 Apr 2026 16:46:36 +0100 Message-ID: <20260427154639.180684-22-dhowells@redhat.com> In-Reply-To: <20260427154639.180684-1-dhowells@redhat.com> References: <20260427154639.180684-1-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. 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 | 8 +++++++- fs/netfs/write_issue.c | 5 ++++- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/afs/dir.c b/fs/afs/dir.c index aaaa55878ffd..3379d01c72fb 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -2206,7 +2206,11 @@ 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) + return 0; + down_read(&dvnode->validate_lock); + } if (is_dir ? test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) : @@ -2214,6 +2218,8 @@ 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 b0e9690bb90c..60525cf6e679 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -819,6 +819,9 @@ 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, @@ -836,7 +839,7 @@ int netfs_writeback_single(struct address_space *mapping, if (!mutex_trylock(&ictx->wb_lock)) { if (wbc->sync_mode == WB_SYNC_NONE) { netfs_stat(&netfs_n_wb_lock_skip); - return 0; + return 1; } netfs_stat(&netfs_n_wb_lock_wait); mutex_lock(&ictx->wb_lock);