From patchwork Tue Nov 19 12:05:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikolay Borisov X-Patchwork-Id: 11251799 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2F2E7930 for ; Tue, 19 Nov 2019 12:06:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 191D121850 for ; Tue, 19 Nov 2019 12:06:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727851AbfKSMGD (ORCPT ); Tue, 19 Nov 2019 07:06:03 -0500 Received: from mx2.suse.de ([195.135.220.15]:49312 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727646AbfKSMGC (ORCPT ); Tue, 19 Nov 2019 07:06:02 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 70A0CB14B; Tue, 19 Nov 2019 12:06:00 +0000 (UTC) From: Nikolay Borisov To: linux-btrfs@vger.kernel.org Cc: Nikolay Borisov Subject: [PATCH 4/6] btrfs: Refactor btrfs_rmap_block to improve readability Date: Tue, 19 Nov 2019 14:05:53 +0200 Message-Id: <20191119120555.6465-5-nborisov@suse.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191119120555.6465-1-nborisov@suse.com> References: <20191119120555.6465-1-nborisov@suse.com> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Move variables to appropriate scope. Remove last BUG_ON in the function and rework error handling accordingly. Make the duplicate detection code more straightforward. Use in_range macro. And give variables more descriptive name by explicitly distinguishing between IO stripe size (size recorded in the chunk item) and data stripe size (the size of an actual stripe, constituting a logical chunk/block group). Signed-off-by: Nikolay Borisov --- fs/btrfs/block-group.c | 53 ++++++++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 22 deletions(-) diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 902c246a9d38..c3b1f304bc70 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -1536,34 +1536,41 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start, struct map_lookup *map; u64 *buf; u64 bytenr; - u64 length; - u64 stripe_nr; - u64 rmap_len; - int i, j, nr = 0; + u64 data_stripe_length; + u64 io_stripe_size; + int i, nr = 0; + int ret = 0; em = btrfs_get_chunk_map(fs_info, chunk_start, 1); if (IS_ERR(em)) return -EIO; map = em->map_lookup; - length = em->len; - rmap_len = map->stripe_len; + data_stripe_length = em->len; + io_stripe_size = map->stripe_len; if (map->type & BTRFS_BLOCK_GROUP_RAID10) - length = div_u64(length, map->num_stripes / map->sub_stripes); + data_stripe_length = div_u64(data_stripe_length, map->num_stripes / map->sub_stripes); else if (map->type & BTRFS_BLOCK_GROUP_RAID0) - length = div_u64(length, map->num_stripes); + data_stripe_length = div_u64(data_stripe_length, map->num_stripes); else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) { - length = div_u64(length, nr_data_stripes(map)); - rmap_len = map->stripe_len * nr_data_stripes(map); + data_stripe_length = div_u64(data_stripe_length, nr_data_stripes(map)); + io_stripe_size = map->stripe_len * nr_data_stripes(map); } buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS); - BUG_ON(!buf); /* -ENOMEM */ + if (!buf) { + ret = -ENOMEM; + goto out; + } for (i = 0; i < map->num_stripes; i++) { - if (map->stripes[i].physical > physical || - map->stripes[i].physical + length <= physical) + bool already_inserted = false; + u64 stripe_nr; + int j; + + if (!in_range(physical, map->stripes[i].physical, + data_stripe_length)) continue; stripe_nr = physical - map->stripes[i].physical; @@ -1575,25 +1582,27 @@ int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start, } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) { stripe_nr = stripe_nr * map->num_stripes + i; } /* else if RAID[56], multiply by nr_data_stripes(). - * Alternatively, just use rmap_len below instead of + * Alternatively, just use io_stripe_size below instead of * map->stripe_len */ - bytenr = chunk_start + stripe_nr * rmap_len; - WARN_ON(nr >= map->num_stripes); + bytenr = chunk_start + stripe_nr * io_stripe_size; + + /* Ensure we don't add duplicate addresses */ for (j = 0; j < nr; j++) { - if (buf[j] == bytenr) + if (buf[j] == bytenr) { + already_inserted = true; break; + } } - if (j == nr) { - WARN_ON(nr >= map->num_stripes); + + if (!already_inserted) buf[nr++] = bytenr; - } } *logical = buf; *naddrs = nr; - *stripe_len = rmap_len; - + *stripe_len = io_stripe_size; +out: free_extent_map(em); return 0; }