Re: [PATCH] btrfs-progs: qgroup: show subvol path when qgroup show

[David Sterba <dsterba@suse.cz>]

On Tue, Oct 10, 2017 at 04:37:09PM +0800, Lu Fengqi wrote:
> Show the absolute subvol path for the associated level-0 qgroup.
> 
> Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
> ---
>  Documentation/btrfs-qgroup.asciidoc |   2 +
>  cmds-qgroup.c                       |   7 +-
>  qgroup.c                            | 130 +++++++++++++++++++++++++++++++++---
>  qgroup.h                            |   1 +
>  4 files changed, 129 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/btrfs-qgroup.asciidoc b/Documentation/btrfs-qgroup.asciidoc
> index 3053f2e6..fb48a917 100644
> --- a/Documentation/btrfs-qgroup.asciidoc
> +++ b/Documentation/btrfs-qgroup.asciidoc
> @@ -93,6 +93,8 @@ Show all qgroups in the btrfs filesystem identified by <path>.
>  print parent qgroup id.
>  -c::::
>  print child qgroup id.
> +-P::::
> +print subvol path.
>  -r::::
>  print limit of referenced size of qgroup.
>  -e::::
> diff --git a/cmds-qgroup.c b/cmds-qgroup.c
> index 38382ea9..9dce84ae 100644
> --- a/cmds-qgroup.c
> +++ b/cmds-qgroup.c
> @@ -277,6 +277,7 @@ static const char * const cmd_qgroup_show_usage[] = {
>  	"Show subvolume quota groups.",
>  	"-p             print parent qgroup id",
>  	"-c             print child qgroup id",
> +	"-P             print subvol path",

I think the path should be printed by default. A more intelligent way of
specifying the columns is on the way, so I'd leave the path without an
option. It's printed as a last item so hopefully will not break tools
that parse the qgrou show output.

>  	"-r             print limit of referenced size of qgroup",
>  	"-e             print limit of exclusive size of qgroup",
>  	"-F             list all qgroups which impact the given path",
> @@ -322,7 +323,7 @@ static int cmd_qgroup_show(int argc, char **argv)
>  			{ NULL, 0, NULL, 0 }
>  		};
>  
> -		c = getopt_long(argc, argv, "pcreFf", long_options, NULL);
> +		c = getopt_long(argc, argv, "pcPreFf", long_options, NULL);
>  		if (c < 0)
>  			break;
>  		switch (c) {
> @@ -334,6 +335,10 @@ static int cmd_qgroup_show(int argc, char **argv)
>  			btrfs_qgroup_setup_print_column(
>  				BTRFS_QGROUP_CHILD);
>  			break;
> +		case 'P':
> +			btrfs_qgroup_setup_print_column(
> +				BTRFS_QGROUP_PATH);
> +			break;
>  		case 'r':
>  			btrfs_qgroup_setup_print_column(
>  				BTRFS_QGROUP_MAX_RFER);
> diff --git a/qgroup.c b/qgroup.c
> index fffdbb12..d618107e 100644
> --- a/qgroup.c
> +++ b/qgroup.c
> @@ -62,6 +62,9 @@ struct btrfs_qgroup {
>  	struct list_head qgroups;
>  	/*qgroups that are members of this group*/
>  	struct list_head members;
> +
> +	/* level-0 qgroup's subvolume path */
> +	char *path;
>  };
>  
>  /*
> @@ -133,6 +136,13 @@ static struct {
>  		.unit_mode	= 0,
>  		.max_len	= 5,
>  	},
> +	{
> +		.name		= "path",
> +		.column_name	= "Path",
> +		.need_print	= 0,
> +		.unit_mode	= 0,
> +		.max_len	= 4,
> +	},
>  	{
>  		.name		= NULL,
>  		.column_name	= NULL,
> @@ -253,6 +263,9 @@ static void print_qgroup_column(struct btrfs_qgroup *qgroup,
>  		len = print_child_column(qgroup);
>  		print_qgroup_column_add_blank(BTRFS_QGROUP_CHILD, len);
>  		break;
> +	case BTRFS_QGROUP_PATH:
> +		len = printf("%s", qgroup->path ? qgroup->path : "---");
> +		print_qgroup_column_add_blank(BTRFS_QGROUP_PATH, len);
>  	default:
>  		break;
>  	}
> @@ -267,7 +280,7 @@ static void print_single_qgroup_table(struct btrfs_qgroup *qgroup)
>  			continue;
>  		print_qgroup_column(qgroup, i);
>  
> -		if (i != BTRFS_QGROUP_CHILD)
> +		if (i != BTRFS_QGROUP_ALL - 1)
>  			printf(" ");
>  	}
>  	printf("\n");
> @@ -284,7 +297,7 @@ static void print_table_head(void)
>  		if (!btrfs_qgroup_columns[i].need_print)
>  			continue;
>  		if ((i == BTRFS_QGROUP_QGROUPID) | (i == BTRFS_QGROUP_PARENT) |
> -			(i == BTRFS_QGROUP_CHILD))
> +			(i == BTRFS_QGROUP_CHILD) | (i == BTRFS_QGROUP_PATH))
>  			printf("%-*s", max_len, btrfs_qgroup_columns[i].name);
>  		else
>  			printf("%*s", max_len, btrfs_qgroup_columns[i].name);
> @@ -296,7 +309,7 @@ static void print_table_head(void)
>  		if (!btrfs_qgroup_columns[i].need_print)
>  			continue;
>  		if ((i == BTRFS_QGROUP_QGROUPID) | (i == BTRFS_QGROUP_PARENT) |
> -			(i == BTRFS_QGROUP_CHILD)) {
> +			(i == BTRFS_QGROUP_CHILD) | (i == BTRFS_QGROUP_PATH)) {
>  			len = strlen(btrfs_qgroup_columns[i].name);
>  			while (len--)
>  				printf("-");
> @@ -627,7 +640,7 @@ static int add_qgroup(struct qgroup_lookup *qgroup_lookup, u64 qgroupid,
>  		      u64 generation, u64 rfer, u64 rfer_cmpr, u64 excl,
>  		      u64 excl_cmpr, u64 flags, u64 max_rfer, u64 max_excl,
>  		      u64 rsv_rfer, u64 rsv_excl, struct btrfs_qgroup *parent,
> -		      struct btrfs_qgroup *child)
> +		      struct btrfs_qgroup *child, char *path)
>  {
>  	struct btrfs_qgroup *bq;
>  	struct btrfs_qgroup_list *list;
> @@ -678,6 +691,8 @@ static int add_qgroup(struct qgroup_lookup *qgroup_lookup, u64 qgroupid,
>  		list_add_tail(&list->next_qgroup, &child->qgroups);
>  		list_add_tail(&list->next_member, &parent->members);
>  	}
> +	bq->path = path;
> +
>  	ret = qgroup_tree_insert(qgroup_lookup, bq);
>  	if (ret) {
>  		error("failed to insert %llu into tree: %s",
> @@ -687,6 +702,88 @@ static int add_qgroup(struct qgroup_lookup *qgroup_lookup, u64 qgroupid,
>  	return ret;
>  }
>  
> +/*
> + * Construct subvolume path for level-0 qgroup according to qgroupid.
> + *
> + * Return a potiner to the path string on success.
> + * Return NULL on error or qgroup level > 0.
> + */
> +static char *qgroups_path_lookup(int fd, struct qgroup_lookup *qgroup_lookup,
> +				 u64 qgroupid)
> +{
> +	struct btrfs_ioctl_search_args args;
> +	struct btrfs_ioctl_search_key *sk = &args.key;
> +	struct btrfs_root_ref *ref;
> +	struct btrfs_ioctl_search_header sh;
> +	struct btrfs_qgroup *bq;
> +	char *name, *path;
> +	u64 subvol_id;
> +	int name_len;
> +	int ret;
> +
> +	/* construct the path only if need print path */
> +	if (!btrfs_qgroup_columns[BTRFS_QGROUP_PATH].need_print)
> +		return NULL;
> +
> +	/* only level-0 qgroup has the corresponding subvolume*/
> +	if (btrfs_qgroup_level(qgroupid))
> +		return NULL;
> +
> +	subvol_id = btrfs_qgroup_subvid(qgroupid);
> +	if (subvol_id < BTRFS_FIRST_FREE_OBJECTID ||
> +			subvol_id > BTRFS_LAST_FREE_OBJECTID)
> +		return NULL;
> +
> +	memset(&args, 0, sizeof(args));
> +
> +	sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
> +	sk->max_type = BTRFS_ROOT_BACKREF_KEY;
> +	sk->min_type = BTRFS_ROOT_BACKREF_KEY;
> +	sk->max_objectid = subvol_id;
> +	sk->min_objectid = subvol_id;
> +	sk->max_offset = (u64)-1;
> +	sk->max_transid = (u64)-1;
> +
> +	sk->nr_items = 4096;
> +	ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
> +	if (ret < 0)
> +		return NULL;
> +	if (!sk->nr_items)
> +		return NULL;
> +
> +	/* resolve the ROOT_BACKREF to get the subvolume name*/
> +	memcpy(&sh, args.buf, sizeof(sh));
> +	ref = (struct btrfs_root_ref *)(args.buf + sizeof(sh));
> +	name_len = btrfs_stack_root_ref_name_len(ref);
> +	name = (char *)(ref + 1);
> +
> +	/*
> +	 * directly return subvolume name if top level is the initial subvolume
> +	 */
> +	if (sh.offset == BTRFS_FS_TREE_OBJECTID)
> +		return strndup(name, name_len);
> +
> +	/*
> +	 * construct path based on the upper subvolume path and the subvolume
> +	 * name
> +	 */
> +	bq = qgroup_tree_search(qgroup_lookup, sh.offset);
> +	if (!bq || bq->qgroupid != sh.offset)
> +		return NULL;
> +
> +	/*
> +	 * 2 means the path delimiter '/' and the terminating null byte ('\0')
> +	 */
> +	path = malloc(strlen(name) + strlen(bq->path) + 2);
> +	if (!path) {
> +		perror("malloc failed");
> +		exit(1);
> +	}
> +	sprintf(path, "%s/%s", bq->path, name);
> +
> +	return path;
> +}
> +
>  static void __free_btrfs_qgroup(struct btrfs_qgroup *bq)
>  {
>  	struct btrfs_qgroup_list *list;
> @@ -706,6 +803,8 @@ static void __free_btrfs_qgroup(struct btrfs_qgroup *bq)
>  		list_del(&list->next_member);
>  		free(list);
>  	}
> +	if (bq->path)
> +		free(bq->path);
>  	free(bq);
>  }
>  
> @@ -979,6 +1078,11 @@ static void __update_columns_max_len(struct btrfs_qgroup *bq,
>  		if (btrfs_qgroup_columns[column].max_len < len)
>  			btrfs_qgroup_columns[column].max_len = len;
>  		break;
> +	case BTRFS_QGROUP_PATH:
> +		len = bq->path ? strlen(bq->path) : 0;
> +		if (btrfs_qgroup_columns[column].max_len < len)
> +			btrfs_qgroup_columns[column].max_len = len;
> +		break;
>  	default:
>  		break;
>  	}
> @@ -1092,8 +1196,12 @@ static int __qgroups_search(int fd, struct qgroup_lookup *qgroup_lookup)
>  				print_status_flag_warning(flags);
>  			} else if (btrfs_search_header_type(sh)
>  				   == BTRFS_QGROUP_INFO_KEY) {
> +				u64 qgroupid;
> +				char *path;
> +
>  				info = (struct btrfs_qgroup_info_item *)
>  				       (args.buf + off);
> +				qgroupid = btrfs_search_header_offset(sh);
>  				a1 = btrfs_stack_qgroup_info_generation(info);
>  				a2 = btrfs_stack_qgroup_info_referenced(info);
>  				a3 =
> @@ -1103,10 +1211,11 @@ static int __qgroups_search(int fd, struct qgroup_lookup *qgroup_lookup)
>  				a5 =
>  				  btrfs_stack_qgroup_info_exclusive_compressed
>  				  (info);
> -				add_qgroup(qgroup_lookup,
> -					btrfs_search_header_offset(sh), a1,
> -					a2, a3, a4, a5, 0, 0, 0, 0, 0, NULL,
> -					NULL);
> +				path = qgroups_path_lookup(fd, qgroup_lookup,
> +							   qgroupid);
> +				add_qgroup(qgroup_lookup, qgroupid, a1, a2, a3,
> +					   a4, a5, 0, 0, 0, 0, 0, NULL, NULL,
> +					   path);
>  			} else if (btrfs_search_header_type(sh)
>  				   == BTRFS_QGROUP_LIMIT_KEY) {
>  				limit = (struct btrfs_qgroup_limit_item *)
> @@ -1124,7 +1233,7 @@ static int __qgroups_search(int fd, struct qgroup_lookup *qgroup_lookup)
>  				add_qgroup(qgroup_lookup,
>  					   btrfs_search_header_offset(sh), 0,
>  					   0, 0, 0, 0, a1, a2, a3, a4, a5,
> -					   NULL, NULL);
> +					   NULL, NULL, NULL);
>  			} else if (btrfs_search_header_type(sh)
>  				   == BTRFS_QGROUP_RELATION_KEY) {
>  				if (btrfs_search_header_offset(sh)
> @@ -1140,7 +1249,8 @@ static int __qgroups_search(int fd, struct qgroup_lookup *qgroup_lookup)
>  					goto skip;
>  				add_qgroup(qgroup_lookup,
>  					   btrfs_search_header_offset(sh), 0,
> -					   0, 0, 0, 0, 0, 0, 0, 0, 0, bq, bq1);
> +					   0, 0, 0, 0, 0, 0, 0, 0, 0, bq, bq1,
> +					   NULL);

Oh no, yet another argument, so it's 15 in total.

>  			} else
>  				goto done;
>  skip:
> diff --git a/qgroup.h b/qgroup.h
> index 875fbdf3..2003f834 100644
> --- a/qgroup.h
> +++ b/qgroup.h
> @@ -59,6 +59,7 @@ enum btrfs_qgroup_column_enum {
>  	BTRFS_QGROUP_MAX_EXCL,
>  	BTRFS_QGROUP_PARENT,
>  	BTRFS_QGROUP_CHILD,
> +	BTRFS_QGROUP_PATH,
>  	BTRFS_QGROUP_ALL,
>  };
>  
> -- 
> 2.14.2
> 
> 
> 
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