[v10,10/41] btrfs: disallow mixed-bg in ZONED mode

Commit Message

Naohiro Aota Nov. 10, 2020, 11:26 a.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

Anand Jain Nov. 20, 2020, 4:32 a.m. UTC | #1

On 10/11/20 7:26 pm, Naohiro Aota wrote:
> 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]>
> ---


Reviewed-by: Anand Jain <[e-mail]>

Thanks.

Patch

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index bd153932606e..f87d35cb9235 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -266,6 +266,13 @@  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: 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;