btrfs: Introduce extent_io_tree::owner to distinguish different io_trees

Btrfs has the following different extent_io_trees used:

- fs_info::free_extents[2]
- btrfs_inode::io_tree - for both normal inodes and the btree inode
- btrfs_inode::io_failure_tree
- btrfs_transaction::dirty_pages
- btrfs_root::dirty_log_pages

If we want to trace changes in those trees, it will be pretty hard to
distinguish them.

Instead of using hard-to-read pointer address, this patch will introduce
a new member extent_io_tree::owner to track the owner.

This modification needs all the callers of extent_io_tree_init() to
accept a new parameter @owner.

This patch provides the basis for later trace events.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -1211,7 +1211,8 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 	root->log_transid_committed = -1;
 	root->last_log_commit = 0;
 	if (!dummy)
-		extent_io_tree_init(fs_info, &root->dirty_log_pages, NULL);
+		extent_io_tree_init(fs_info, &root->dirty_log_pages,
+				    IO_TREE_ROOT_DIRTY_LOG_PAGES, NULL);
 
 	memset(&root->root_key, 0, sizeof(root->root_key));
 	memset(&root->root_item, 0, sizeof(root->root_item));
@@ -2141,7 +2142,8 @@ static void btrfs_init_btree_inode(struct btrfs_fs_info *fs_info)
 	inode->i_mapping->a_ops = &btree_aops;
 
 	RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
-	extent_io_tree_init(fs_info, &BTRFS_I(inode)->io_tree, inode);
+	extent_io_tree_init(fs_info, &BTRFS_I(inode)->io_tree,
+			    IO_TREE_INODE_IO, inode);
 	BTRFS_I(inode)->io_tree.track_uptodate = false;
 	extent_map_tree_init(&BTRFS_I(inode)->extent_tree);
 
@@ -2751,8 +2753,10 @@ int open_ctree(struct super_block *sb,
 	fs_info->block_group_cache_tree = RB_ROOT;
 	fs_info->first_logical_byte = (u64)-1;
 
-	extent_io_tree_init(fs_info, &fs_info->freed_extents[0], NULL);
-	extent_io_tree_init(fs_info, &fs_info->freed_extents[1], NULL);
+	extent_io_tree_init(fs_info, &fs_info->freed_extents[0],
+			    IO_TREE_FS_INFO_FREED_EXTENTS0, NULL);
+	extent_io_tree_init(fs_info, &fs_info->freed_extents[1],
+			    IO_TREE_FS_INFO_FREED_EXTENTS1, NULL);
 	fs_info->pinned_extents = &fs_info->freed_extents[0];
 	set_bit(BTRFS_FS_BARRIER, &fs_info->flags);
 

fs/btrfs/extent_io.c

@@ -233,7 +233,8 @@ void __cold extent_io_exit(void)
 }
 
 void extent_io_tree_init(struct btrfs_fs_info *fs_info,
-			 struct extent_io_tree *tree, void *private_data)
+			 struct extent_io_tree *tree, unsigned int owner,
+			 void *private_data)
 {
 	tree->fs_info = fs_info;
 	tree->state = RB_ROOT;
@@ -241,6 +242,7 @@ void extent_io_tree_init(struct btrfs_fs_info *fs_info,
 	tree->dirty_bytes = 0;
 	spin_lock_init(&tree->lock);
 	tree->private_data = private_data;
+	tree->owner = owner;
 }
 
 static struct extent_state *alloc_extent_state(gfp_t mask)

fs/btrfs/extent_io.h

@@ -106,12 +106,27 @@ struct extent_io_ops {
 				    int mirror);
 };
 
+enum {
+	IO_TREE_FS_INFO_FREED_EXTENTS0,
+	IO_TREE_FS_INFO_FREED_EXTENTS1,
+	IO_TREE_INODE_IO,
+	IO_TREE_INODE_IO_FAILURE,
+	IO_TREE_RELOC_BLOCKS,
+	IO_TREE_TRANS_DIRTY_PAGES,
+	IO_TREE_ROOT_DIRTY_LOG_PAGES,
+	IO_TREE_SELFTEST,
+};
+
 struct extent_io_tree {
 	struct rb_root state;
 	struct btrfs_fs_info *fs_info;
 	void *private_data;
 	u64 dirty_bytes;
 	bool track_uptodate;
+
+	/* Who owns this io tree, should be one of IO_TREE_* */
+	u8 owner;
+
 	spinlock_t lock;
 	const struct extent_io_ops *ops;
 };
@@ -241,7 +256,8 @@ typedef struct extent_map *(get_extent_t)(struct btrfs_inode *inode,
 					  int create);
 
 void extent_io_tree_init(struct btrfs_fs_info *fs_info,
-			 struct extent_io_tree *tree, void *private_data);
+			 struct extent_io_tree *tree, unsigned int owner,
+			 void *private_data);
 int try_release_extent_mapping(struct page *page, gfp_t mask);
 int try_release_extent_buffer(struct page *page);
 int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,

fs/btrfs/inode.c

@@ -9182,8 +9182,9 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
 
 	inode = &ei->vfs_inode;
 	extent_map_tree_init(&ei->extent_tree);
-	extent_io_tree_init(fs_info, &ei->io_tree, inode);
-	extent_io_tree_init(fs_info, &ei->io_failure_tree, inode);
+	extent_io_tree_init(fs_info, &ei->io_tree, IO_TREE_INODE_IO, inode);
+	extent_io_tree_init(fs_info, &ei->io_failure_tree,
+			    IO_TREE_INODE_IO_FAILURE, inode);
 	ei->io_tree.track_uptodate = true;
 	ei->io_failure_tree.track_uptodate = true;
 	atomic_set(&ei->sync_writers, 0);

fs/btrfs/relocation.c

@@ -4234,7 +4234,8 @@ static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
 	INIT_LIST_HEAD(&rc->dirty_subvol_roots);
 	backref_cache_init(&rc->backref_cache);
 	mapping_tree_init(&rc->reloc_root_tree);
-	extent_io_tree_init(fs_info, &rc->processed_blocks, NULL);
+	extent_io_tree_init(fs_info, &rc->processed_blocks,
+			    IO_TREE_RELOC_BLOCKS, NULL);
 	return rc;
 }
 

fs/btrfs/tests/btrfs-tests.c

@@ -115,8 +115,10 @@ struct btrfs_fs_info *btrfs_alloc_dummy_fs_info(u32 nodesize, u32 sectorsize)
 	INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
 	INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
 	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
-	extent_io_tree_init(fs_info, &fs_info->freed_extents[0], NULL);
-	extent_io_tree_init(fs_info, &fs_info->freed_extents[1], NULL);
+	extent_io_tree_init(fs_info, &fs_info->freed_extents[0],
+			    IO_TREE_FS_INFO_FREED_EXTENTS0, NULL);
+	extent_io_tree_init(fs_info, &fs_info->freed_extents[1],
+			    IO_TREE_FS_INFO_FREED_EXTENTS1, NULL);
 	fs_info->pinned_extents = &fs_info->freed_extents[0];
 	set_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
 

fs/btrfs/tests/extent-io-tests.c

@@ -77,7 +77,11 @@ static int test_find_delalloc(u32 sectorsize)
 		return -ENOMEM;
 	}
 
-	extent_io_tree_init(NULL, &tmp, NULL);
+	/*
+	 * Passing NULL as we don't have fs_info but tracepoints are not used
+	 * at this point
+	 */
+	extent_io_tree_init(NULL, &tmp, IO_TREE_SELFTEST, NULL);
 
 	/*
 	 * First go through and create and mark all of our pages dirty, we pin

fs/btrfs/transaction.c

@@ -275,7 +275,7 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,
 	spin_lock_init(&cur_trans->dropped_roots_lock);
 	list_add_tail(&cur_trans->list, &fs_info->trans_list);
 	extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
-			     fs_info->btree_inode);
+			IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
 	fs_info->generation++;
 	cur_trans->transid = fs_info->generation;
 	fs_info->running_transaction = cur_trans;