From: Omar Sandoval <osandov@fb.com>
Date: Fri, 11 May 2018 13:13:38 -0700
Subject: Btrfs: get rid of unused orphan infrastructure
Git-commit: a575ceeb1338e7eae6d14e223b077b3c6fd3bb6b
Patch-mainline: v4.18-rc1
References: bsc#1111469

Now that we don't keep long-standing reservations for orphan items,
root->orphan_block_rsv isn't used. We can git rid of it, along with:

- root->orphan_lock, which was used to protect root->orphan_block_rsv
- root->orphan_inodes, which was used as a refcount for root->orphan_block_rsv
- BTRFS_INODE_ORPHAN_META_RESERVED, which was used to track reservations
  in root->orphan_block_rsv
- btrfs_orphan_commit_root(), which was the last user of any of these
  and does nothing else

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/btrfs_inode.h |    1 -
 fs/btrfs/ctree.h       |    8 --------
 fs/btrfs/disk-io.c     |    9 ---------
 fs/btrfs/extent-tree.c |   38 --------------------------------------
 fs/btrfs/inode.c       |   43 +------------------------------------------
 fs/btrfs/transaction.c |    1 -
 6 files changed, 1 insertion(+), 99 deletions(-)

--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -33,7 +33,6 @@
  * new data the application may have written before commit.
  */
 #define BTRFS_INODE_ORDERED_DATA_CLOSE		0
-#define BTRFS_INODE_ORPHAN_META_RESERVED	1
 #define BTRFS_INODE_DUMMY			2
 #define BTRFS_INODE_IN_DEFRAG			3
 #define BTRFS_INODE_HAS_ASYNC_EXTENT		5
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1242,9 +1242,6 @@ struct btrfs_root {
 	spinlock_t log_extents_lock[2];
 	struct list_head logged_list[2];
 
-	spinlock_t orphan_lock;
-	atomic_t orphan_inodes;
-	struct btrfs_block_rsv *orphan_block_rsv;
 	int orphan_cleanup_state;
 
 	spinlock_t inode_lock;
@@ -2774,9 +2771,6 @@ void btrfs_free_reserved_data_space_noqu
 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
 				  struct btrfs_fs_info *fs_info);
 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans);
-int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
-				  struct btrfs_inode *inode);
-void btrfs_orphan_release_metadata(struct btrfs_inode *inode);
 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
 				     struct btrfs_block_rsv *rsv,
 				     int nitems,
@@ -3268,8 +3262,6 @@ int btrfs_update_inode_fallback(struct b
 int btrfs_orphan_add(struct btrfs_trans_handle *trans,
 		struct btrfs_inode *inode);
 int btrfs_orphan_cleanup(struct btrfs_root *root);
-void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
-			      struct btrfs_root *root);
 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size);
 void btrfs_invalidate_inodes(struct btrfs_root *root);
 void btrfs_add_delayed_iput(struct inode *inode);
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1237,7 +1237,6 @@ static void __setup_root(struct btrfs_ro
 	root->inode_tree = RB_ROOT;
 	INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
 	root->block_rsv = NULL;
-	root->orphan_block_rsv = NULL;
 
 	INIT_LIST_HEAD(&root->dirty_list);
 	INIT_LIST_HEAD(&root->root_list);
@@ -1247,7 +1246,6 @@ static void __setup_root(struct btrfs_ro
 	INIT_LIST_HEAD(&root->ordered_root);
 	INIT_LIST_HEAD(&root->logged_list[0]);
 	INIT_LIST_HEAD(&root->logged_list[1]);
-	spin_lock_init(&root->orphan_lock);
 	spin_lock_init(&root->inode_lock);
 	spin_lock_init(&root->delalloc_lock);
 	spin_lock_init(&root->ordered_extent_lock);
@@ -1268,7 +1266,6 @@ static void __setup_root(struct btrfs_ro
 	atomic_set(&root->log_commit[1], 0);
 	atomic_set(&root->log_writers, 0);
 	atomic_set(&root->log_batch, 0);
-	atomic_set(&root->orphan_inodes, 0);
 	refcount_set(&root->refs, 1);
 	atomic_set(&root->will_be_snapshoted, 0);
 	root->log_transid = 0;
@@ -3745,8 +3742,6 @@ static void free_fs_root(struct btrfs_ro
 {
 	iput(root->ino_cache_inode);
 	WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
-	btrfs_free_block_rsv(root->fs_info, root->orphan_block_rsv);
-	root->orphan_block_rsv = NULL;
 	if (root->anon_dev)
 		free_anon_bdev(root->anon_dev);
 	if (root->subv_writers)
@@ -3837,7 +3832,6 @@ int btrfs_commit_super(struct btrfs_fs_i
 
 void close_ctree(struct btrfs_fs_info *fs_info)
 {
-	struct btrfs_root *root = fs_info->tree_root;
 	int ret;
 
 	set_bit(BTRFS_FS_CLOSING_START, &fs_info->flags);
@@ -3930,9 +3924,6 @@ void close_ctree(struct btrfs_fs_info *f
 
 	btrfs_free_stripe_hash_table(fs_info);
 
-	__btrfs_free_block_rsv(root->orphan_block_rsv);
-	root->orphan_block_rsv = NULL;
-
 	mutex_lock(&fs_info->chunk_mutex);
 	while (!list_empty(&fs_info->pinned_chunks)) {
 		struct extent_map *em;
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5908,44 +5908,6 @@ void btrfs_trans_release_chunk_metadata(
 	trans->chunk_bytes_reserved = 0;
 }
 
-/* Can only return 0 or -ENOSPC */
-int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
-				  struct btrfs_inode *inode)
-{
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
-	struct btrfs_root *root = inode->root;
-	/*
-	 * We always use trans->block_rsv here as we will have reserved space
-	 * for our orphan when starting the transaction, using get_block_rsv()
-	 * here will sometimes make us choose the wrong block rsv as we could be
-	 * doing a reloc inode for a non refcounted root.
-	 */
-	struct btrfs_block_rsv *src_rsv = trans->block_rsv;
-	struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
-
-	/*
-	 * We need to hold space in order to delete our orphan item once we've
-	 * added it, so this takes the reservation so we can release it later
-	 * when we are truly done with the orphan item.
-	 */
-	u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
-
-	trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
-			num_bytes, 1);
-	return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
-}
-
-void btrfs_orphan_release_metadata(struct btrfs_inode *inode)
-{
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
-	struct btrfs_root *root = inode->root;
-	u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
-
-	trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
-			num_bytes, 0);
-	btrfs_block_rsv_release(fs_info, root->orphan_block_rsv, num_bytes);
-}
-
 /*
  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
  * root: the root of the parent directory
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3251,42 +3251,6 @@ void btrfs_run_delayed_iputs(struct btrf
 }
 
 /*
- * This is called in transaction commit time. If there are no orphan
- * files in the subvolume, it removes orphan item and frees block_rsv
- * structure.
- */
-void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
-			      struct btrfs_root *root)
-{
-	struct btrfs_fs_info *fs_info = root->fs_info;
-	struct btrfs_block_rsv *block_rsv;
-
-	if (atomic_read(&root->orphan_inodes) ||
-	    root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
-		return;
-
-	spin_lock(&root->orphan_lock);
-	if (atomic_read(&root->orphan_inodes)) {
-		spin_unlock(&root->orphan_lock);
-		return;
-	}
-
-	if (root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE) {
-		spin_unlock(&root->orphan_lock);
-		return;
-	}
-
-	block_rsv = root->orphan_block_rsv;
-	root->orphan_block_rsv = NULL;
-	spin_unlock(&root->orphan_lock);
-
-	if (block_rsv) {
-		WARN_ON(block_rsv->size > 0);
-		btrfs_free_block_rsv(fs_info, block_rsv);
-	}
-}
-
-/*
  * This creates an orphan entry for the given inode in case something goes wrong
  * in the middle of an unlink.
  *
@@ -3483,12 +3447,7 @@ int btrfs_orphan_cleanup(struct btrfs_ro
 
 	root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
 
-	if (root->orphan_block_rsv)
-		btrfs_block_rsv_release(fs_info, root->orphan_block_rsv,
-					(u64)-1);
-
-	if (root->orphan_block_rsv ||
-	    test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
+	if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
 		trans = btrfs_join_transaction(root);
 		if (!IS_ERR(trans))
 			btrfs_end_transaction(trans);
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1276,7 +1276,6 @@ static noinline int commit_fs_roots(stru
 
 			btrfs_free_log(trans, root);
 			btrfs_update_reloc_root(trans, root);
-			btrfs_orphan_commit_root(trans, root);
 
 			btrfs_save_ino_cache(root, trans);