Attachment 877550 Details for Bug 1051985 – Bug fix for your problem

[patch] Bug fix for your problem

0001-Btrfs-scrub-raid56-stripes-in-the-right-way.patch (text/plain), 2.76 KB, created by Wang Shilong on 2014-03-22 07:19:37 UTC

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Creator: Wang Shilong

Created: 2014-03-22 07:19:37 UTC

Size: 2.76 KB

patch

obsolete

>From 24e0950c8128bbb78ab131fc7ce7ab3a226ac6ae Mon Sep 17 00:00:00 2001
>From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
>Date: Sat, 22 Mar 2014 14:52:44 +0800
>Subject: [PATCH] Btrfs: scrub raid56 stripes in the right way
>
>Steps to reproduce:
> # mkfs.btrfs -f /dev/sda[8-11] -m raid5 -d raid5
> # mount /dev/sda8 /mnt
> # btrfs scrub start -BR /mnt
> # echo $? <--unverified errors make return value be 3
>
>This is because we don't setup right mapping between physical
>and logical address for raid56, which makes checksum mismatch.
>But we will find everthing is fine later when rechecking using
>btrfs_map_block().
>
>This patch fixed the problem by settuping right mapping and
>we only verify data stripes' checksums.
>
>Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
>---
> fs/btrfs/scrub.c | 33 +++++++++++++++++++++++++--------
> 1 file changed, 25 insertions(+), 8 deletions(-)
>
>diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
>index db21a13..4182b44a 100644
>--- a/fs/btrfs/scrub.c
>+++ b/fs/btrfs/scrub.c
>@@ -2267,16 +2267,12 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
> 	u64 extent_logical;
> 	u64 extent_physical;
> 	u64 extent_len;
>+	u64 stripe_nr;
>+	u64 tmp;
>+	int stripe_index;
> 	struct btrfs_device *extent_dev;
> 	int extent_mirror_num;
>-	int stop_loop;
>-
>-	if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
>-			 BTRFS_BLOCK_GROUP_RAID6)) {
>-		if (num >= nr_data_stripes(map)) {
>-			return 0;
>-		}
>-	}
>+	int stop_loop = 0;
> 
> 	nstripes = length;
> 	offset = 0;
>@@ -2296,6 +2292,14 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
> 	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
> 		increment = map->stripe_len;
> 		mirror_num = num % map->num_stripes + 1;
>+	} else if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
>+				BTRFS_BLOCK_GROUP_RAID6)) {
>+		if (num < nr_data_stripes(map))
>+			offset = num * map->stripe_len;
>+		else
>+			offset = (nr_data_stripes(map) - 1) * map->stripe_len;
>+		increment = map->stripe_len * nr_data_stripes(map);
>+		mirror_num = 1;
> 	} else {
> 		increment = map->stripe_len;
> 		mirror_num = 1;
>@@ -2361,6 +2365,18 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
> 	logic_end = logical + increment * nstripes;
> 	ret = 0;
> 	while (logical < logic_end) {
>+		/* skip parity */
>+		if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
>+				BTRFS_BLOCK_GROUP_RAID6)) {
>+			stripe_nr = logical - base;
>+			do_div(stripe_nr, map->stripe_len);
>+
>+			stripe_index = do_div(stripe_nr, nr_data_stripes(map));
>+			tmp = stripe_nr + stripe_index;
>+			stripe_index = do_div(tmp, map->num_stripes);
>+			if (stripe_index != num)
>+				goto skip;
>+		}
> 		/*
> 		 * canceled?
> 		 */
>@@ -2521,6 +2537,7 @@ next:
> 			path->slots[0]++;
> 		}
> 		btrfs_release_path(path);
>+skip:
> 		logical += increment;
> 		physical += map->stripe_len;
> 		spin_lock(&sctx->stat_lock);
>-- 
>1.9.0
>

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