btrfs: move trans_handle_cachep out of ctree.h

This is local to the transaction code, remove it from ctree.h and
inode.c, create new helpers in the transaction to handle the init work
and move the cachep locally to transaction.c.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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/ctree.h

@@ -41,7 +41,6 @@ struct btrfs_pending_snapshot;
 struct btrfs_delayed_ref_root;
 struct btrfs_space_info;
 struct btrfs_block_group;
-extern struct kmem_cache *btrfs_trans_handle_cachep;
 extern struct kmem_cache *btrfs_path_cachep;
 extern struct kmem_cache *btrfs_free_space_cachep;
 extern struct kmem_cache *btrfs_free_space_bitmap_cachep;

fs/btrfs/inode.c

@@ -107,7 +107,6 @@ static const struct address_space_operations btrfs_aops;
 static const struct file_operations btrfs_dir_file_operations;
 
 static struct kmem_cache *btrfs_inode_cachep;
-struct kmem_cache *btrfs_trans_handle_cachep;
 struct kmem_cache *btrfs_path_cachep;
 struct kmem_cache *btrfs_free_space_cachep;
 struct kmem_cache *btrfs_free_space_bitmap_cachep;
@@ -8926,7 +8925,6 @@ void __cold btrfs_destroy_cachep(void)
 	rcu_barrier();
 	bioset_exit(&btrfs_dio_bioset);
 	kmem_cache_destroy(btrfs_inode_cachep);
-	kmem_cache_destroy(btrfs_trans_handle_cachep);
 	kmem_cache_destroy(btrfs_path_cachep);
 	kmem_cache_destroy(btrfs_free_space_cachep);
 	kmem_cache_destroy(btrfs_free_space_bitmap_cachep);
@@ -8941,12 +8939,6 @@ int __init btrfs_init_cachep(void)
 	if (!btrfs_inode_cachep)
 		goto fail;
 
-	btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
-			sizeof(struct btrfs_trans_handle), 0,
-			SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
-	if (!btrfs_trans_handle_cachep)
-		goto fail;
-
 	btrfs_path_cachep = kmem_cache_create("btrfs_path",
 			sizeof(struct btrfs_path), 0,
 			SLAB_MEM_SPREAD, NULL);

fs/btrfs/super.c

@@ -2739,10 +2739,14 @@ static int __init init_btrfs_fs(void)
 	if (err)
 		goto free_compress;
 
-	err = extent_state_init_cachep();
+	err = btrfs_transaction_init();
 	if (err)
 		goto free_cachep;
 
+	err = extent_state_init_cachep();
+	if (err)
+		goto free_transaction;
+
 	err = extent_buffer_init_cachep();
 	if (err)
 		goto free_extent_cachep;
@@ -2811,6 +2815,8 @@ static int __init init_btrfs_fs(void)
 	extent_buffer_free_cachep();
 free_extent_cachep:
 	extent_state_free_cachep();
+free_transaction:
+	btrfs_transaction_exit();
 free_cachep:
 	btrfs_destroy_cachep();
 free_compress:
@@ -2822,6 +2828,7 @@ static int __init init_btrfs_fs(void)
 
 static void __exit exit_btrfs_fs(void)
 {
+	btrfs_transaction_exit();
 	btrfs_destroy_cachep();
 	btrfs_delayed_ref_exit();
 	btrfs_auto_defrag_exit();

fs/btrfs/transaction.c

@@ -24,6 +24,8 @@
 #include "space-info.h"
 #include "zoned.h"
 
+static struct kmem_cache *btrfs_trans_handle_cachep;
+
 #define BTRFS_ROOT_TRANS_TAG 0
 
 /*
@@ -2600,3 +2602,18 @@ void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
 		btrfs_warn(fs_info,
 			"unknown pending changes left 0x%lx, ignoring", prev);
 }
+
+int __init btrfs_transaction_init(void)
+{
+	btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
+			sizeof(struct btrfs_trans_handle), 0,
+			SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
+	if (!btrfs_trans_handle_cachep)
+		return -ENOMEM;
+	return 0;
+}
+
+void __cold btrfs_transaction_exit(void)
+{
+	kmem_cache_destroy(btrfs_trans_handle_cachep);
+}

fs/btrfs/transaction.h

@@ -236,4 +236,7 @@ void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
 			    struct btrfs_root *root);
 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
 
+int __init btrfs_transaction_init(void);
+void __cold btrfs_transaction_exit(void);
+
 #endif