Re: [PATCH 2/2] btrfs: pretty print leaked root name

[Nikolay Borisov <nborisov@suse.com>]

On 20.08.20 г. 23:00 ч., Josef Bacik wrote:
> 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>
> ---
>  fs/btrfs/disk-io.c    |  8 +++++---
>  fs/btrfs/print-tree.c | 37 +++++++++++++++++++++++++++++++++++++
>  fs/btrfs/print-tree.h |  1 +
>  3 files changed, 43 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index ac6d6fddd5f4..a7358e0f59de 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -1506,11 +1506,13 @@ void btrfs_check_leaked_roots(struct btrfs_fs_info *fs_info)
>  	struct btrfs_root *root;
>  
>  	while (!list_empty(&fs_info->allocated_roots)) {
> +		const char *name = btrfs_root_name(root->root_key.objectid);
> +
>  		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,
> -			  refcount_read(&root->refs));
> +		btrfs_err(fs_info, "leaked root %s%lld-%llu refcount %d",

nit: Won't this string result in some rather awkward looking strings,
such as:

"leaked root ROOT_TREE<objectid>-<offset>..." i.e shouldn't the
(objectid,offset) pair be marked with parentheses?

> +			  name ? name : "", root->root_key.objectid,
> +			  root->root_key.offset, refcount_read(&root->refs));
>  		while (refcount_read(&root->refs) > 1)
>  			btrfs_put_root(root);
>  		btrfs_put_root(root);
> diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
> index 61f44e78e3c9..c633aec8973d 100644
> --- a/fs/btrfs/print-tree.c
> +++ b/fs/btrfs/print-tree.c
> @@ -7,6 +7,43 @@
>  #include "disk-io.h"
>  #include "print-tree.h"
>  
> +struct name_map {
> +	u64 id;
> +	const char *name;
> +};
> +
> +static const struct 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_ROOT_TREE_DIR_OBJECTID,		"ROOT_TREE_DIR"		},
> +	{ BTRFS_CSUM_TREE_OBJECTID,		"CSUM_TREE"		},
> +	{ BTRFS_TREE_LOG_OBJECTID,		"TREE_LOG"		},
> +	{ BTRFS_QUOTA_TREE_OBJECTID,		"QUOTA_TREE"		},
> +	{ BTRFS_TREE_RELOC_OBJECTID,		"TREE_RELOC"		},
> +	{ 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)
> +{
> +	int i;
> +
> +	if (objectid >= BTRFS_FIRST_FREE_OBJECTID &&
> +	    objectid <= BTRFS_LAST_FREE_OBJECTID)
> +		return NULL;
> +
> +	for (i = 0; i < ARRAY_SIZE(root_map); i++) {
> +		if (root_map[i].id == objectid)
> +			return root_map[i].name;
> +	}
> +
> +	return NULL;
> +}
> +
>  static void print_chunk(struct extent_buffer *eb, struct btrfs_chunk *chunk)
>  {
>  	int num_stripes = btrfs_chunk_num_stripes(eb, chunk);
> diff --git a/fs/btrfs/print-tree.h b/fs/btrfs/print-tree.h
> index e6bb38fd75ad..dffdfa495297 100644
> --- a/fs/btrfs/print-tree.h
> +++ b/fs/btrfs/print-tree.h
> @@ -8,5 +8,6 @@
>  
>  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);
>  
>  #endif
>