btrfs: zoned: calculate allocation offset for conventional zones

Conventional zones do not have a write pointer, so we cannot use it to
determine the allocation offset for sequential allocation if a block
group contains a conventional zone.

But instead, we can consider the end of the highest addressed extent in
the block group for the allocation offset.

For new block group, we cannot calculate the allocation offset by
consulting the extent tree, because it can cause deadlock by taking
extent buffer lock after chunk mutex, which is already taken in
btrfs_make_block_group(). Since it is a new block group anyways, we can
simply set the allocation offset to 0.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 4f3152d7b98f..d27db3993e51 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -41,7 +41,7 @@ u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
 int btrfs_reset_device_zone(struct btrfs_device *device, u64 physical,
 			    u64 length, u64 *bytes);
 int btrfs_ensure_empty_zones(struct btrfs_device *device, u64 start, u64 size);
-int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache);
+int btrfs_load_block_group_zone_info(struct btrfs_block_group *cache, bool new);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
 				     struct blk_zone *zone)
@@ -118,7 +118,7 @@ static inline int btrfs_ensure_empty_zones(struct btrfs_device *device,
 }
 
 static inline int btrfs_load_block_group_zone_info(
-		struct btrfs_block_group *cache)
+		struct btrfs_block_group *cache, bool new)
 {
 	return 0;
 }