[PATCH] btrfs: handle failures of set_extent_bits in add_excluded_extent

[PATCH] btrfs: handle failures of set_extent_bits in add_excluded_extent

[Gu Jinxiang]

set_extent_bits may return 0/-EEXIST, so return the result in
add_excluded_extent. And handle the failures in upper callers.

Caller of add_excluded_extent and failure process currently:
exclude_super_stripes
	<- btrfs_make_block_group  //handles the failure
	<- btrfs_read_block_groups //handles the failure
__exclude_logged_extent
	<- btrfs_exclude_logged_extents
	<- btrfs_alloc_logged_file_extent //propagate failure to upper
					caller
Add logic of propagate return value of __exclude_logged_extent to
btrfs_exclude_logged_extents.

Signed-off-by: Gu Jinxiang <gujx@cn.fujitsu.com>
---
 fs/btrfs/extent-tree.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 75cfb80d2551..28fd71579141 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -215,11 +215,16 @@ static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 			       u64 start, u64 num_bytes)
 {
 	u64 end = start + num_bytes - 1;
-	set_extent_bits(&fs_info->freed_extents[0],
+	int ret = 0;
+
+	ret = set_extent_bits(&fs_info->freed_extents[0],
 			start, end, EXTENT_UPTODATE);
-	set_extent_bits(&fs_info->freed_extents[1],
+	if (ret)
+		goto out;
+	ret = set_extent_bits(&fs_info->freed_extents[1],
 			start, end, EXTENT_UPTODATE);
-	return 0;
+out:
+	return ret;
 }
 
 static void free_excluded_extents(struct btrfs_fs_info *fs_info,
@@ -6463,6 +6468,7 @@ int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
 	struct btrfs_key key;
 	int found_type;
 	int i;
+	int ret = 0;
 
 	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
 		return 0;
@@ -6479,10 +6485,14 @@ int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
 			continue;
 		key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
 		key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
-		__exclude_logged_extent(fs_info, key.objectid, key.offset);
+		ret = __exclude_logged_extent(fs_info, key.objectid,
+				key.offset);
+		if (ret)
+			goto out;
 	}
 
-	return 0;
+out:
+	return ret;
 }
 
 static void
-- 
1.9.1

Re: [PATCH] btrfs: handle failures of set_extent_bits in add_excluded_extent

[Nikolay Borisov]

On 22.05.2018 06:51, Gu Jinxiang wrote:
> set_extent_bits may return 0/-EEXIST, so return the result in
> add_excluded_extent. And handle the failures in upper callers.
> 
> Caller of add_excluded_extent and failure process currently:
> exclude_super_stripes
> 	<- btrfs_make_block_group  //handles the failure
> 	<- btrfs_read_block_groups //handles the failure

> __exclude_logged_extent
> 	<- btrfs_exclude_logged_extents
> 	<- btrfs_alloc_logged_file_extent //propagate failure to upper
> 					caller
> Add logic of propagate return value of __exclude_logged_extent to
> btrfs_exclude_logged_extents.
> 
> Signed-off-by: Gu Jinxiang <gujx@cn.fujitsu.com>
> ---
>  fs/btrfs/extent-tree.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 75cfb80d2551..28fd71579141 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -215,11 +215,16 @@ static int add_excluded_extent(struct btrfs_fs_info *fs_info,
>  			       u64 start, u64 num_bytes)
>  {
>  	u64 end = start + num_bytes - 1;
> -	set_extent_bits(&fs_info->freed_extents[0],
> +	int ret = 0;
> +
> +	ret = set_extent_bits(&fs_info->freed_extents[0],
>  			start, end, EXTENT_UPTODATE);
> -	set_extent_bits(&fs_info->freed_extents[1],
> +	if (ret)
> +		goto out;
> +	ret = set_extent_bits(&fs_info->freed_extents[1],
>  			start, end, EXTENT_UPTODATE);
> -	return 0;
> +out:
> +	return ret;
>  }
>  
>  static void free_excluded_extents(struct btrfs_fs_info *fs_info,
> @@ -6463,6 +6468,7 @@ int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
>  	struct btrfs_key key;
>  	int found_type;
>  	int i;
> +	int ret = 0;
>  
>  	if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
>  		return 0;
> @@ -6479,10 +6485,14 @@ int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
>  			continue;
>  		key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
>  		key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
> -		__exclude_logged_extent(fs_info, key.objectid, key.offset);
> +		ret = __exclude_logged_extent(fs_info, key.objectid,
> +				key.offset);
> +		if (ret)
> +			goto out;
>  	}
>  
> -	return 0;
> +out:
> +	return ret;
>  }

The 2nd and 3rd hunks need to go in a separate patch.
__exclude_logged_extent can return an error value for any number of
reasons (btrfs_lookup_block_group failing, btrfs_remove_free_space
failing or add_excluded_extents also failing). SO what you are actually
fixing here is __exclude_logged_extent return value not being handled in
btrfs_exclude_logged_extent which is a separate issue from
add_excluded_extent always returning 0. So put this in a separate patch.

>  
>  static void
>