[PATCH v7 08/39] btrfs: disallow mixed-bg in ZONED mode

[Naohiro Aota <naohiro.aota@wdc.com>]

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.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/zoned.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 6bce654bb0e8..8cd43d2d5611 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -260,6 +260,13 @@ 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;
 
-- 
2.27.0