Re: [PATCH 10/12] Btrfs-progs: add show subcommand to subvol cli

[Wang Shilong <wangshilong1991@gmail.com>]

Hi,
> This adds show sub-command to the btrfs subvol cli
> to display detailed inforamtion of the given subvol
> or snapshot.
>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  btrfs-list.c     |  25 +++++++--
>  btrfs-list.h     |   3 +-
>  cmds-subvolume.c | 155 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
>  man/btrfs.8.in   |   6 +++
>  4 files changed, 182 insertions(+), 7 deletions(-)
>
> diff --git a/btrfs-list.c b/btrfs-list.c
> index 656de10..1915ece 100644
> --- a/btrfs-list.c
> +++ b/btrfs-list.c
> @@ -1335,6 +1335,22 @@ static void print_subvolume_column(struct root_info *subv,
>  	}
>  }
>  
> +static void print_single_volume_info_raw(struct root_info *subv, char *raw_prefix)
> +{
> +	int i;
> +
> +	for (i = 0; i < BTRFS_LIST_ALL; i++) {
> +		if (!btrfs_list_columns[i].need_print)
> +			continue;
> +
> +		if (raw_prefix)
> +			printf("%s",raw_prefix);
> +
> +		print_subvolume_column(subv, i);
> +	}
> +	printf("\n");
> +}
> +
>  static void print_single_volume_info_table(struct root_info *subv)
>  {
>  	int i;
> @@ -1401,7 +1417,7 @@ static void print_all_volume_info_tab_head()
>  }
>  
>  static void print_all_volume_info(struct root_lookup *sorted_tree,
> -				  int layout)
> +				  int layout, char *raw_prefix)
>  {
>  	struct rb_node *n;
>  	struct root_info *entry;
> @@ -1419,6 +1435,9 @@ static void print_all_volume_info(struct root_lookup *sorted_tree,
>  		case BTRFS_LIST_LAYOUT_TABLE:
>  			print_single_volume_info_table(entry);
>  			break;
> +		case BTRFS_LIST_LAYOUT_RAW:
> +			print_single_volume_info_raw(entry, raw_prefix);
> +			break;
>  		}
>  		n = rb_next(n);
>  	}
> @@ -1445,7 +1464,7 @@ int btrfs_list_subvols(int fd, struct root_lookup *root_lookup)
>  
>  int btrfs_list_subvols_print(int fd, struct btrfs_list_filter_set *filter_set,
>  		       struct btrfs_list_comparer_set *comp_set,
> -		       int layout)
> +		       int layout, char *raw_prefix)
>  {
>  	struct root_lookup root_lookup;
>  	struct root_lookup root_sort;
> @@ -1457,7 +1476,7 @@ int btrfs_list_subvols_print(int fd, struct btrfs_list_filter_set *filter_set,
>  	__filter_and_sort_subvol(&root_lookup, &root_sort, filter_set,
>  				 comp_set, fd);
>  
> -	print_all_volume_info(&root_sort, layout);
> +	print_all_volume_info(&root_sort, layout, raw_prefix);
>  	__free_all_subvolumn(&root_lookup);
>  
>  	return 0;
> diff --git a/btrfs-list.h b/btrfs-list.h
> index 5b60068..09d35f7 100644
> --- a/btrfs-list.h
> +++ b/btrfs-list.h
> @@ -20,6 +20,7 @@
>  
>  #define BTRFS_LIST_LAYOUT_DEFAULT	0
>  #define BTRFS_LIST_LAYOUT_TABLE	1
> +#define BTRFS_LIST_LAYOUT_RAW		2
>  
>  /*
>   * one of these for each root we find.
> @@ -150,7 +151,7 @@ int btrfs_list_setup_comparer(struct btrfs_list_comparer_set **comp_set,
>  
>  int btrfs_list_subvols_print(int fd, struct btrfs_list_filter_set *filter_set,
>  		       struct btrfs_list_comparer_set *comp_set,
> -			int is_tab_result);
> +			int layout, char *raw_prefix);
>  int btrfs_list_find_updated_files(int fd, u64 root_id, u64 oldest_gen);
>  int btrfs_list_get_default_subvolume(int fd, u64 *default_id);
>  char *btrfs_list_path_for_root(int fd, u64 root);
> diff --git a/cmds-subvolume.c b/cmds-subvolume.c
> index bb9629f..6a14c4c 100644
> --- a/cmds-subvolume.c
> +++ b/cmds-subvolume.c
> @@ -24,6 +24,7 @@
>  #include <libgen.h>
>  #include <limits.h>
>  #include <getopt.h>
> +#include <uuid/uuid.h>
>  
>  #include "kerncompat.h"
>  #include "ioctl.h"
> @@ -418,10 +419,10 @@ static int cmd_subvol_list(int argc, char **argv)
>  
>  	if (is_tab_result)
>  		ret = btrfs_list_subvols_print(fd, filter_set, comparer_set,
> -				BTRFS_LIST_LAYOUT_TABLE);
> +				BTRFS_LIST_LAYOUT_TABLE, NULL);
>  	else
>  		ret = btrfs_list_subvols_print(fd, filter_set, comparer_set,
> -				BTRFS_LIST_LAYOUT_DEFAULT);
> +				BTRFS_LIST_LAYOUT_DEFAULT, NULL);
>  	if (ret)
>  		return 19;
>  	return 0;
> @@ -634,7 +635,7 @@ static int cmd_subvol_get_default(int argc, char **argv)
>  	btrfs_list_setup_print_column(BTRFS_LIST_PATH);
>  
>  	ret = btrfs_list_subvols_print(fd, filter_set, NULL,
> -		BTRFS_LIST_LAYOUT_DEFAULT);
> +		BTRFS_LIST_LAYOUT_DEFAULT, NULL);
>  	if (ret)
>  		return 19;
>  	return 0;
> @@ -721,6 +722,153 @@ static int cmd_find_new(int argc, char **argv)
>  	return 0;
>  }
>  
> +static const char * const cmd_subvol_show_usage[] = {
> +	"btrfs subvolume show <subvol-path>",
> +	"Show more information of the subvolume",
> +	NULL
> +};
> +
> +static int cmd_subvol_show(int argc, char **argv)
> +{
> +	struct root_info get_ri;
> +	struct btrfs_list_filter_set *filter_set;
> +	char tstr[256];
> +	char uuidparse[37];
> +	char *fullpath = NULL, *svpath = NULL, *mnt = NULL;
> +	char raw_prefix[] = "\t\t\t\t";
> +	u64 sv_id, mntid;
> +	int fd = -1, mntfd = -1;
> +	int ret = -1;
> +
> +	if (check_argc_exact(argc, 2))
> +		usage(cmd_subvol_show_usage);
> +
> +	fullpath = realpath(argv[1], 0);
> +	if (!fullpath) {
> +		fprintf(stderr, "ERROR: finding real path for '%s', %s\n",
> +			argv[1], strerror(errno));
> +		goto out;
> +	}
> +
> +	ret = test_issubvolume(fullpath);
> +	if (ret < 0) {
> +		fprintf(stderr, "ERROR: error accessing '%s'\n", fullpath);
> +		goto out;
> +	}
> +	if (!ret) {
> +		fprintf(stderr, "ERROR: '%s' is not a subvolume\n", fullpath);
> +		ret = -1;
> +		goto out;
> +	}
> +
> +	ret = find_mount_root(fullpath, &mnt);
> +	if (ret < 0) {
> +		fprintf(stderr, "ERROR: find_mount_root failed on %s: "
> +				"%s\n", fullpath, strerror(-ret));
> +		goto out;
> +	}
> +	ret = -1;
> +	svpath = get_subvol_name(mnt, fullpath);
> +
> +	fd = open_file_or_dir(fullpath);
> +	if (fd < 0) {
> +		fprintf(stderr, "ERROR: can't access '%s'\n", fullpath);
> +		goto out;
> +	}
> +
> +	sv_id = btrfs_list_get_path_rootid(fd);
> +	if (sv_id < 0) {
> +		fprintf(stderr, "ERROR: can't get rootid for '%s'\n",
> +			fullpath);
> +		goto out;
> +	}
> +
> +	mntfd = open_file_or_dir(mnt);
> +	if (mntfd < 0) {
> +		fprintf(stderr, "ERROR: can't access '%s'\n", mnt);
> +		goto out;
> +	}
> +
> +	mntid = btrfs_list_get_path_rootid(mntfd);
> +	if (mntid < 0) {
> +		fprintf(stderr, "ERROR: can't get rootid for '%s'\n", mnt);
> +		goto out;
> +	}
> +
> +	if (sv_id == BTRFS_FS_TREE_OBJECTID) {
> +		printf("%s is btrfs root\n", fullpath);
> +		goto out;
> +	}
> +
> +	memset(&get_ri, 0, sizeof(get_ri));
> +	get_ri.root_id = sv_id;
> +
> +	if (btrfs_get_subvol(mntfd, &get_ri)) {
> +		fprintf(stderr, "ERROR: can't find '%s'\n",
> +			svpath);
> +		goto out;
> +	}
> +
> +	ret = 0;
> +	/* print the info */
    I think it will be better if you can move the following
    printing to a function..it will make the code more clear and
    readable..

    Thanks,
    Wang
> +	printf("%s\n", fullpath);
> +	printf("\tName: \t\t\t%s\n", get_ri.name);
> +
> +	if (uuid_is_null(get_ri.uuid))
> +		strcpy(uuidparse, "-");
> +	else
> +		uuid_unparse(get_ri.uuid, uuidparse);
> +	printf("\tuuid: \t\t\t%s\n", uuidparse);
> +
> +	if (uuid_is_null(get_ri.puuid))
> +		strcpy(uuidparse, "-");
> +	else
> +		uuid_unparse(get_ri.puuid, uuidparse);
> +	printf("\tParent uuid: \t\t%s\n", uuidparse);
> +
> +	if (get_ri.otime)
> +		strftime(tstr, 256, "%Y-%m-%d %X",
> +			 localtime(&get_ri.otime));
> +	else
> +		strcpy(tstr, "-");
> +	printf("\tCreation time: \t\t%s\n", tstr);
> +
> +	printf("\tObject ID: \t\t%llu\n", get_ri.root_id);
> +	printf("\tGeneration (Gen): \t%llu\n", get_ri.gen);
> +	printf("\tGen at creation: \t%llu\n", get_ri.ogen);
> +	printf("\tParent: \t\t%llu\n", get_ri.ref_tree);
> +	printf("\tTop Level: \t\t%llu\n", get_ri.top_id);
> +
> +	/* print the snapshots of the given subvol if any*/
> +	printf("\tSnapshot(s):\n");
> +	filter_set = btrfs_list_alloc_filter_set();
> +	btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_BY_PARENT,
> +				get_ri.uuid);
> +	btrfs_list_setup_print_column(BTRFS_LIST_PATH);
> +	btrfs_list_subvols_print(fd, filter_set, NULL, BTRFS_LIST_LAYOUT_RAW,
> +			raw_prefix);
> +
> +	/* clean up */
> +	if (get_ri.path)
> +		free(get_ri.path);
> +	if (get_ri.name)
> +		free(get_ri.name);
> +	if (get_ri.full_path)
> +		free(get_ri.full_path);
> +
> +out:
> +	if (mntfd >= 0)
> +		close(mntfd);
> +	if (fd >= 0)
> +		close(fd);
> +	if (mnt)
> +		free(mnt);
> +	if (fullpath)
> +		free(fullpath);
> +
> +	return ret;
> +}
> +
>  const struct cmd_group subvolume_cmd_group = {
>  	subvolume_cmd_group_usage, NULL, {
>  		{ "create", cmd_subvol_create, cmd_subvol_create_usage, NULL, 0 },
> @@ -732,6 +880,7 @@ const struct cmd_group subvolume_cmd_group = {
>  		{ "set-default", cmd_subvol_set_default,
>  			cmd_subvol_set_default_usage, NULL, 0 },
>  		{ "find-new", cmd_find_new, cmd_find_new_usage, NULL, 0 },
> +		{ "show", cmd_subvol_show, cmd_subvol_show_usage, NULL, 0 },
>  		{ 0, 0, 0, 0, 0 }
>  	}
>  };
> diff --git a/man/btrfs.8.in b/man/btrfs.8.in
> index d20e332..0008a06 100644
> --- a/man/btrfs.8.in
> +++ b/man/btrfs.8.in
> @@ -17,6 +17,8 @@ btrfs \- control a btrfs filesystem
>  .PP
>  \fBbtrfs\fP \fBsubvolume get-default\fP\fI <path>\fP
>  .PP
> +\fBbtrfs\fP \fBsubvolume show\fP\fI <path>\fP
> +.PP
>  \fBbtrfs\fP \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] \
>  [-s \fIstart\fR] [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> \
>  [<\fIfile\fR>|<\fIdir\fR>...]
> @@ -158,6 +160,10 @@ Get the default subvolume of the filesystem \fI<path>\fR. The output format
>  is similar to \fBsubvolume list\fR command.
>  .TP
>  
> +\fBsubvolume show\fR\fI <path>\fR
> +Show information of a given subvolume in the \fI<path>\fR.
> +.TP
> +
>  \fBfilesystem defragment\fP -c[zlib|lzo] [-l \fIlen\fR] [-s \fIstart\fR] \
>  [-t \fIsize\fR] -[vf] <\fIfile\fR>|<\fIdir\fR> [<\fIfile\fR>|<\fIdir\fR>...]
>