diff mbox

[2/2] Btrfs: scrub raid56 stripes in the right way

Message ID 1395655091-5318-2-git-send-email-wangsl.fnst@cn.fujitsu.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Wang Shilong March 24, 2014, 9:58 a.m. UTC 
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 mappings 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(-)

Comments

Wang Shilong March 28, 2014, noon UTC | #1 
Oops, this patch is not working right, please ignore this one,
i will send a v2.

Thanks,
Wang
On 03/24/2014 05:58 PM, Wang Shilong wrote:
> 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 mappings 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);

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diff mbox

Patch

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);