[PATCH v3 07/27] btrfs: disable tree-log in HMZONED mode

[Naohiro Aota]

Extent buffers for tree-log tree are allocated scattered between other
metadata's extent buffers, and btrfs_sync_log() writes out only the
tree-log buffers. This behavior breaks sequential writing rule, which is
mandatory in sequential required zones.

Actually, we don't have much benefit using tree-logging with HMZONED mode,
until we can allocate tree-log buffer sequentially. So, disable tree-log
entirely in HMZONED mode.

Signed-off-by: Naohiro Aota <naohiro.a...@wdc.com>
---
 fs/btrfs/hmzoned.c | 6 ++++++
 fs/btrfs/super.c   | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
index 0770b1f58bd9..e07e76af1e82 100644
--- a/fs/btrfs/hmzoned.c
+++ b/fs/btrfs/hmzoned.c
@@ -256,5 +256,11 @@ int btrfs_check_mountopts_hmzoned(struct btrfs_fs_info 
*info)
                return -EINVAL;
        }
 
+       if (!btrfs_test_opt(info, NOTREELOG)) {
+               btrfs_err(info,
+                 "cannot enable tree log with HMZONED mode");
+               return -EINVAL;
+       }
+
        return 0;
 }
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 496d8b74f9a2..396238e099bc 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -447,6 +447,10 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char 
*options,
                        btrfs_set_opt(info->mount_opt, SPACE_CACHE);
        }
 
+       if (btrfs_fs_incompat(info, HMZONED))
+               btrfs_set_and_info(info, NOTREELOG,
+                                  "disabling tree log with HMZONED mode");
+
        /*
         * Even the options are empty, we still need to do extra check
         * against new flags
-- 
2.22.0