From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CBD6D2D9787; Thu, 28 May 2026 20:25:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779999952; cv=none; b=a52cO3UHOTdM6pYqU09yLXMMvkRugXJIf1RtXwXyUHdUklqNA4kCpci/KRhzekveqZucawo36ZXkfyfkYYKGb2zdEbE78z5FmOnZDTgHVn6Oa9CohmD/q2cg1zx1FUjxdMDWpQoHky2NK+wgqvUi6gYze3CVpzItSJtmrdyIbuo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779999952; c=relaxed/simple; bh=XzWzasvIYYijoHV5ephMxXdo7ygWi7jcH+mlOHO6+oA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qAJX01yyBmL9zFa20Z61PPTuK0BowXYHVzdBJ2kYOGwEKGtkmkUwUKuL/nDEEC3WjZkBU5Rvc5JOkY9nQtSE3oeO4TYUE5Xtq5bObPZDn2fdMQwI2UjEdRDnew2dryI+yQOwgx7SLLBNjSL3TS/VV4sG5XnYdhnxS3/KzfxbmSQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Xxkltqw+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Xxkltqw+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 397341F000E9; Thu, 28 May 2026 20:25:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779999950; bh=wUozUQ4l5E6B/QabXv/09OHOijH4N4hybBpp36SmrmM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Xxkltqw+izbEgGJ+3erglFMMjyY9KHXOdkvNP4/RDtfH3r9Is9OkidMYgkKqjP1La bwjyjea+JNiUzK7/cvYeMxmIRr9ZaGzHPlkJPapvLsRFqcy1r9DGxaL2kRTF3XuYf4 F0mrmbUw5YRptZ0SUbkEch+xJZIT2YpdNh0dnnfU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Howells , Marc Dionne , linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org, Christian Brauner , Sasha Levin Subject: [PATCH 6.18 249/377] netfs, afs: Fix write skipping in dir/link writepages Date: Thu, 28 May 2026 21:48:07 +0200 Message-ID: <20260528194645.588721456@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194638.371537336@linuxfoundation.org> References: <20260528194638.371537336@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit 9871938f99cc6cb266a77265491660e2375271f5 ] 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 Link: https://patch.msgid.link/20260512123404.719402-24-dhowells@redhat.com cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- 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 89d36e3e5c799..fa84610e0b0d9 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -2207,7 +2207,14 @@ 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) : @@ -2215,6 +2222,8 @@ 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 9bf05099155dc..03d170b9022b7 100644 --- a/fs/netfs/write_issue.c +++ b/fs/netfs/write_issue.c @@ -829,6 +829,9 @@ 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, @@ -845,8 +848,10 @@ 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); -- 2.53.0