btrfs: remove unused btrfs_cond_migrate_bytes

The last user of this was removed in 7f9fe614 ("btrfs: improve
global reserve stealing logic"), drop this code as it's no longer called
by anybody.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/block-rsv.c

@@ -325,31 +325,6 @@ void btrfs_block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
 	spin_unlock(&block_rsv->lock);
 }
 
-int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
-			     struct btrfs_block_rsv *dest, u64 num_bytes,
-			     int min_factor)
-{
-	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
-	u64 min_bytes;
-
-	if (global_rsv->space_info != dest->space_info)
-		return -ENOSPC;
-
-	spin_lock(&global_rsv->lock);
-	min_bytes = div_factor(global_rsv->size, min_factor);
-	if (global_rsv->reserved < min_bytes + num_bytes) {
-		spin_unlock(&global_rsv->lock);
-		return -ENOSPC;
-	}
-	global_rsv->reserved -= num_bytes;
-	if (global_rsv->reserved < global_rsv->size)
-		global_rsv->full = false;
-	spin_unlock(&global_rsv->lock);
-
-	btrfs_block_rsv_add_bytes(dest, num_bytes, true);
-	return 0;
-}
-
 void btrfs_update_global_block_rsv(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;

fs/btrfs/block-rsv.h

@@ -70,9 +70,6 @@ int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
 			    struct btrfs_block_rsv *dst_rsv, u64 num_bytes,
 			    bool update_size);
 int btrfs_block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv, u64 num_bytes);
-int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
-			     struct btrfs_block_rsv *dest, u64 num_bytes,
-			     int min_factor);
 void btrfs_block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
 			       u64 num_bytes, bool update_size);
 u64 btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,