[PATCH 01/13] btrfs: factor out helper for single device IO check

Johannes Thumshirn
2023-12-12T12:38:16Z

The check in btrfs_map_block() deciding if a particular I/O is targeting a
single device is getting more and more convoluted.

Factor out the check conditions into a helper function, with no functional
change otherwise.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
fs/btrfs/volumes.c | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 1cc6b5d5eb61..1011178a244c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6330,6 +6330,28 @@ static int set_io_stripe(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
return 0;
}

+static bool is_single_device_io(struct btrfs_fs_info *fs_info,
+ struct btrfs_io_stripe *smap,
+ struct btrfs_chunk_map *map,
+ int num_alloc_stripes,
+ enum btrfs_map_op op, int mirror_num)
+{
+ if (!smap)
+ return false;
+
+ if (num_alloc_stripes != 1)
+ return false;
+
+ if (btrfs_need_stripe_tree_update(fs_info, map->type) &&
+ op != BTRFS_MAP_READ)
+ return false;
+
+ if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1)
+ return false;
+
+ return true;
+}
+
/*
* Map one logical range to one or more physical ranges.
*
@@ -6532,10 +6554,8 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
* physical block information on the stack instead of allocating an
* I/O context structure.
*/
- if (smap && num_alloc_stripes == 1 &&
- !(btrfs_need_stripe_tree_update(fs_info, map->type) &&
- op != BTRFS_MAP_READ) &&
- !((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1)) {
+ if (is_single_device_io(fs_info, smap, map, num_alloc_stripes, op,
+ mirror_num)) {
ret = set_io_stripe(fs_info, op, logical, length, smap, map,
stripe_index, stripe_offset, stripe_nr);
if (mirror_num_ret)

--
2.43.0