From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756890AbcCBCNG (ORCPT ); Tue, 1 Mar 2016 21:13:06 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:45955 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753223AbcCAXrY (ORCPT ); Tue, 1 Mar 2016 18:47:24 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kent Overstreet , Jens Axboe Subject: [PATCH 3.14 012/130] bcache: Change refill_dirty() to always scan entire disk if necessary Date: Tue, 1 Mar 2016 15:44:23 -0800 Message-Id: <20160301234500.196377220@linuxfoundation.org> X-Mailer: git-send-email 2.7.2 In-Reply-To: <20160301234459.768886030@linuxfoundation.org> References: <20160301234459.768886030@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kent Overstreet commit 627ccd20b4ad3ba836472468208e2ac4dfadbf03 upstream. Previously, it would only scan the entire disk if it was starting from the very start of the disk - i.e. if the previous scan got to the end. This was broken by refill_full_stripes(), which updates last_scanned so that refill_dirty was never triggering the searched_from_start path. But if we change refill_dirty() to always scan the entire disk if necessary, regardless of what last_scanned was, the code gets cleaner and we fix that bug too. Signed-off-by: Kent Overstreet Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/writeback.c | 37 ++++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-) --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -323,6 +323,10 @@ void bcache_dev_sectors_dirty_add(struct static bool dirty_pred(struct keybuf *buf, struct bkey *k) { + struct cached_dev *dc = container_of(buf, struct cached_dev, writeback_keys); + + BUG_ON(KEY_INODE(k) != dc->disk.id); + return KEY_DIRTY(k); } @@ -372,11 +376,24 @@ next: } } +/* + * Returns true if we scanned the entire disk + */ static bool refill_dirty(struct cached_dev *dc) { struct keybuf *buf = &dc->writeback_keys; + struct bkey start = KEY(dc->disk.id, 0, 0); struct bkey end = KEY(dc->disk.id, MAX_KEY_OFFSET, 0); - bool searched_from_start = false; + struct bkey start_pos; + + /* + * make sure keybuf pos is inside the range for this disk - at bringup + * we might not be attached yet so this disk's inode nr isn't + * initialized then + */ + if (bkey_cmp(&buf->last_scanned, &start) < 0 || + bkey_cmp(&buf->last_scanned, &end) > 0) + buf->last_scanned = start; if (dc->partial_stripes_expensive) { refill_full_stripes(dc); @@ -384,14 +401,20 @@ static bool refill_dirty(struct cached_d return false; } - if (bkey_cmp(&buf->last_scanned, &end) >= 0) { - buf->last_scanned = KEY(dc->disk.id, 0, 0); - searched_from_start = true; - } - + start_pos = buf->last_scanned; bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred); - return bkey_cmp(&buf->last_scanned, &end) >= 0 && searched_from_start; + if (bkey_cmp(&buf->last_scanned, &end) < 0) + return false; + + /* + * If we get to the end start scanning again from the beginning, and + * only scan up to where we initially started scanning from: + */ + buf->last_scanned = start; + bch_refill_keybuf(dc->disk.c, buf, &start_pos, dirty_pred); + + return bkey_cmp(&buf->last_scanned, &start_pos) >= 0; } static int bch_writeback_thread(void *arg)