[v9,10/41] btrfs: disallow mixed-bg in ZONED mode

Commit Message

Naohiro Aota Oct. 30, 2020, 1:51 p.m. UTC

Placing both data and metadata in a block group is impossible in ZONED
mode. For data, we can allocate a space for it and write it immediately
after the allocation. For metadata, however, we cannot do so, because the
logical addresses are recorded in other metadata buffers to build up the
trees. As a result, a data buffer can be placed after a metadata buffer,
which is not written yet. Writing out the data buffer will break the
sequential write rule.

This commit check and disallow MIXED_BG with ZONED mode.

Signed-off-by: Naohiro Aota <[e-mail]>
Reviewed-by: Josef Bacik <[e-mail]>
---
 fs/btrfs/zoned.c | 7 +++++++
 1 file changed, 7 insertions(+)

Comments

David Sterba Nov. 3, 2020, 1:01 p.m. UTC | #1

On Fri, Oct 30, 2020 at 10:51:17PM +0900, Naohiro Aota wrote:
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -257,6 +257,13 @@ int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
>  		goto out;
>  	}
>  
> +	if (btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
> +		btrfs_err(fs_info,
> +			  "ZONED mode is not allowed for mixed block groups");

		"zoned: mixed block groups not supported"

> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
>  	fs_info->zone_size = zone_size;
>  	fs_info->max_zone_append_size = max_zone_append_size;
>  
> -- 
> 2.27.0

Patch

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 1939b3ee6c10..ae509699da14 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -257,6 +257,13 @@  int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info)
 		goto out;
 	}
 
+	if (btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
+		btrfs_err(fs_info,
+			  "ZONED mode is not allowed for mixed block groups");
+		ret = -EINVAL;
+		goto out;
+	}
+
 	fs_info->zone_size = zone_size;
 	fs_info->max_zone_append_size = max_zone_append_size;