[PATCH 2/4] btrfs: zoned: finish BG when there are no more allocatable bytes left

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

Currently, btrfs_zone_finish_endio() finishes a block group only when the
written region reaches the end of the block group. We can also finish the
block group when no more allocation is possible.

Cc: stable@vger.kernel.org # 5.16+
Fixes: be1a1d7a5d24 ("btrfs: zoned: finish fully written block group")
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 fs/btrfs/zoned.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 9cddafe78fb1..0f6ca3587c3b 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2017,6 +2017,7 @@ bool btrfs_can_activate_zone(struct btrfs_fs_devices *fs_devices, u64 flags)
 void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, u64 logical, u64 length)
 {
 	struct btrfs_block_group *block_group;
+	u64 min_use;
 
 	if (!btrfs_is_zoned(fs_info))
 		return;
@@ -2024,7 +2025,14 @@ void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, u64 logical, u64 len
 	block_group = btrfs_lookup_block_group(fs_info, logical);
 	ASSERT(block_group);
 
-	if (logical + length < block_group->start + block_group->zone_capacity)
+	/* No MIXED BG on zoned btrfs. */
+	if (block_group->flags & BTRFS_BLOCK_GROUP_DATA)
+		min_use = fs_info->sectorsize;
+	else
+		min_use = fs_info->nodesize;
+
+	/* Bail out if we can allocate more data from this BG. */
+	if (logical + length + min_use <= block_group->start + block_group->zone_capacity)
 		goto out;
 
 	__btrfs_zone_finish(block_group, true);
-- 
2.35.1