[PATCH] btrfs: Always output error message when key/level verification fails

[PATCH] btrfs: Always output error message when key/level verification fails

[Qu Wenruo]

We have internal report of strange transaction abort due to EUCLEAN
without any error message.

Since error message inside verify_level_key() is only enabled for
CONFIG_BTRFS_DEBUG, the error message won't output for most distro.

This patch will make the error message mandatory, so when problem
happens we know what's causing the problem.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/disk-io.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 45bf6be9e751..d04ae6deba94 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -435,10 +435,10 @@ static int verify_level_key(struct btrfs_fs_info *fs_info,
 	if (found_level != level) {
 #ifdef CONFIG_BTRFS_DEBUG
 		WARN_ON(1);
+#endif
 		btrfs_err(fs_info,
 "tree level mismatch detected, bytenr=%llu level expected=%u has=%u",
 			  eb->start, level, found_level);
-#endif
 		return -EIO;
 	}
 
@@ -459,9 +459,10 @@ static int verify_level_key(struct btrfs_fs_info *fs_info,
 		btrfs_item_key_to_cpu(eb, &found_key, 0);
 	ret = btrfs_comp_cpu_keys(first_key, &found_key);
 
-#ifdef CONFIG_BTRFS_DEBUG
 	if (ret) {
+#ifdef CONFIG_BTRFS_DEBUG
 		WARN_ON(1);
+#endif
 		btrfs_err(fs_info,
 "tree first key mismatch detected, bytenr=%llu parent_transid=%llu key expected=(%llu,%u,%llu) has=(%llu,%u,%llu)",
 			  eb->start, parent_transid, first_key->objectid,
@@ -469,7 +470,6 @@ static int verify_level_key(struct btrfs_fs_info *fs_info,
 			  found_key.objectid, found_key.type,
 			  found_key.offset);
 	}
-#endif
 	return ret;
 }
 
-- 
2.20.1

Re: [PATCH] btrfs: Always output error message when key/level verification fails

[Nikolay Borisov]

On 17.01.19 г. 3:27 ч., Qu Wenruo wrote:
> We have internal report of strange transaction abort due to EUCLEAN
> without any error message.
> 
> Since error message inside verify_level_key() is only enabled for
> CONFIG_BTRFS_DEBUG, the error message won't output for most distro.
> 
> This patch will make the error message mandatory, so when problem
> happens we know what's causing the problem.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  fs/btrfs/disk-io.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 45bf6be9e751..d04ae6deba94 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -435,10 +435,10 @@ static int verify_level_key(struct btrfs_fs_info *fs_info,
>  	if (found_level != level) {
>  #ifdef CONFIG_BTRFS_DEBUG
>  		WARN_ON(1);
> +#endif
>  		btrfs_err(fs_info,
>  "tree level mismatch detected, bytenr=%llu level expected=%u has=%u",
>  			  eb->start, level, found_level);
> -#endif
>  		return -EIO;
>  	}
>  
> @@ -459,9 +459,10 @@ static int verify_level_key(struct btrfs_fs_info *fs_info,
>  		btrfs_item_key_to_cpu(eb, &found_key, 0);
>  	ret = btrfs_comp_cpu_keys(first_key, &found_key);
>  
> -#ifdef CONFIG_BTRFS_DEBUG
>  	if (ret) {
> +#ifdef CONFIG_BTRFS_DEBUG
>  		WARN_ON(1);
> +#endif

Rather than WARN_ON(1) WARN() could be used, but that's something very
minor.

>  		btrfs_err(fs_info,
>  "tree first key mismatch detected, bytenr=%llu parent_transid=%llu key expected=(%llu,%u,%llu) has=(%llu,%u,%llu)",
>  			  eb->start, parent_transid, first_key->objectid,
> @@ -469,7 +470,6 @@ static int verify_level_key(struct btrfs_fs_info *fs_info,
>  			  found_key.objectid, found_key.type,
>  			  found_key.offset);
>  	}
> -#endif
>  	return ret;
>  }
>  
>