btrfs: pretty print leaked root name

I'm a actual human being so am incapable of converting u64 to s64 in my
head, so add a helper to get the pretty name of a root objectid and use
that helper to spit out the name for any special roots for leaked roots,
so I don't have to scratch my head and figure out which root I messed up
the refs for.

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/disk-io.c

@@ -1503,10 +1503,12 @@ void btrfs_check_leaked_roots(struct btrfs_fs_info *fs_info)
 	struct btrfs_root *root;
 
 	while (!list_empty(&fs_info->allocated_roots)) {
+		char buf[BTRFS_ROOT_NAME_BUF_LEN];
+
 		root = list_first_entry(&fs_info->allocated_roots,
 					struct btrfs_root, leak_list);
-		btrfs_err(fs_info, "leaked root %llu-%llu refcount %d",
-			  root->root_key.objectid, root->root_key.offset,
+		btrfs_err(fs_info, "leaked root %s refcount %d",
+			  btrfs_root_name(root->root_key.objectid, buf),
 			  refcount_read(&root->refs));
 		while (refcount_read(&root->refs) > 1)
 			btrfs_put_root(root);

fs/btrfs/print-tree.c

@@ -7,6 +7,44 @@
 #include "disk-io.h"
 #include "print-tree.h"
 
+struct root_name_map {
+	u64 id;
+	char name[16];
+};
+
+static const struct root_name_map root_map[] = {
+	{ BTRFS_ROOT_TREE_OBJECTID,		"ROOT_TREE"		},
+	{ BTRFS_EXTENT_TREE_OBJECTID,		"EXTENT_TREE"		},
+	{ BTRFS_CHUNK_TREE_OBJECTID,		"CHUNK_TREE"		},
+	{ BTRFS_DEV_TREE_OBJECTID,		"DEV_TREE"		},
+	{ BTRFS_FS_TREE_OBJECTID,		"FS_TREE"		},
+	{ BTRFS_CSUM_TREE_OBJECTID,		"CSUM_TREE"		},
+	{ BTRFS_TREE_LOG_OBJECTID,		"TREE_LOG"		},
+	{ BTRFS_QUOTA_TREE_OBJECTID,		"QUOTA_TREE"		},
+	{ BTRFS_UUID_TREE_OBJECTID,		"UUID_TREE"		},
+	{ BTRFS_FREE_SPACE_TREE_OBJECTID,	"FREE_SPACE_TREE"	},
+	{ BTRFS_DATA_RELOC_TREE_OBJECTID,	"DATA_RELOC_TREE"	},
+};
+
+const char *btrfs_root_name(u64 objectid, char *buf)
+{
+	int i;
+
+	if (objectid == BTRFS_TREE_RELOC_OBJECTID) {
+		snprintf(buf, BTRFS_ROOT_NAME_BUF_LEN,
+			 "TREE_RELOC offset=%llu", objectid);
+		return buf;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(root_map); i++) {
+		if (root_map[i].id == objectid)
+			return root_map[i].name;
+	}
+
+	snprintf(buf, BTRFS_ROOT_NAME_BUF_LEN, "%llu", objectid);
+	return buf;
+}
+
 static void print_chunk(struct extent_buffer *eb, struct btrfs_chunk *chunk)
 {
 	int num_stripes = btrfs_chunk_num_stripes(eb, chunk);

fs/btrfs/print-tree.h

@@ -6,7 +6,11 @@
 #ifndef BTRFS_PRINT_TREE_H
 #define BTRFS_PRINT_TREE_H
 
+/* Buffer size to contain tree name and possibly additional data (offset) */
+#define BTRFS_ROOT_NAME_BUF_LEN				48
+
 void btrfs_print_leaf(struct extent_buffer *l);
 void btrfs_print_tree(struct extent_buffer *c, bool follow);
+const char *btrfs_root_name(u64 objectid, char *buf);
 
 #endif