btrfs-progs: create get_subvol_info()

get_subvol_info() is useful as we are adding more features around
subvolume. This function was inline with the function
cmd_subvol_show().

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index f62ab95..2319684 100644 (file)
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -908,21 +908,21 @@ static const char * const cmd_subvol_show_usage[] = {
 static int cmd_subvol_show(int argc, char **argv)
 {
        struct root_info get_ri;
-       struct btrfs_list_filter_set *filter_set;
+       struct btrfs_list_filter_set *filter_set = NULL;
        char tstr[256];
        char uuidparse[BTRFS_UUID_UNPARSED_SIZE];
-       char *fullpath = NULL, *svpath = NULL, *mnt = NULL;
+       char *fullpath = NULL;
        char raw_prefix[] = "\t\t\t\t";
-       u64 sv_id;
-       int fd = -1, mntfd = -1;
+       int fd = -1;
        int ret = 1;
-       DIR *dirstream1 = NULL, *dirstream2 = NULL;
+       DIR *dirstream1 = NULL;
 
        clean_args_no_options(argc, argv, cmd_subvol_show_usage);
 
        if (check_argc_exact(argc - optind, 1))
                usage(cmd_subvol_show_usage);
 
+       memset(&get_ri, 0, sizeof(get_ri));
        fullpath = realpath(argv[optind], NULL);
        if (!fullpath) {
                error("cannot find real path for '%s': %s",
@@ -930,57 +930,23 @@ static int cmd_subvol_show(int argc, char **argv)
                goto out;
        }
 
-       ret = test_issubvolume(fullpath);
-       if (ret < 0) {
-               error("cannot access subvolume %s: %s", fullpath,
-                       strerror(-ret));
-               goto out;
-       }
-       if (!ret) {
-               error("not a subvolume: %s", fullpath);
-               ret = 1;
-               goto out;
-       }
-
-       ret = find_mount_root(fullpath, &mnt);
-       if (ret < 0) {
-               error("find_mount_root failed on '%s': %s",
-                       fullpath, strerror(-ret));
-               goto out;
-       }
-       if (ret > 0) {
-               error("%s doesn't belong to btrfs mount point", fullpath);
-               goto out;
-       }
-       ret = 1;
-       svpath = get_subvol_name(mnt, fullpath);
-
-       fd = btrfs_open_dir(fullpath, &dirstream1, 1);
-       if (fd < 0)
-               goto out;
-
-       ret = btrfs_list_get_path_rootid(fd, &sv_id);
-       if (ret) {
-               error("can't get rootid for '%s'", fullpath);
-               goto out;
-       }
-
-       mntfd = btrfs_open_dir(mnt, &dirstream2, 1);
-       if (mntfd < 0)
-               goto out;
-
-       if (sv_id == BTRFS_FS_TREE_OBJECTID) {
+       ret = get_subvol_info(fullpath, &get_ri);
+       if (ret == 2) {
+               /*
+                * Since the top level btrfs was given don't
+                * take that as error
+                */
                printf("%s is toplevel subvolume\n", fullpath);
+               ret = 0;
                goto out;
        }
-
-       memset(&get_ri, 0, sizeof(get_ri));
-       get_ri.root_id = sv_id;
-
-       ret = btrfs_get_subvol(mntfd, &get_ri);
        if (ret) {
-               error("can't find '%s'", svpath);
-               goto out;
+               ret < 0 ?
+                       error("Failed to get subvol info %s: %s\n",
+                                                       fullpath, strerror(-ret)):
+                       error("Failed to get subvol info %s: %d\n",
+                                                       fullpath, ret);
+               return ret;
        }
 
        /* print the info */
@@ -1031,19 +997,23 @@ static int cmd_subvol_show(int argc, char **argv)
        btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_BY_PARENT,
                                (u64)(unsigned long)get_ri.uuid);
        btrfs_list_setup_print_column(BTRFS_LIST_PATH);
+
+       fd = open_file_or_dir(fullpath, &dirstream1);
+       if (fd < 0) {
+               fprintf(stderr, "ERROR: can't access '%s'\n", fullpath);
+               goto out;
+       }
        btrfs_list_subvols_print(fd, filter_set, NULL, BTRFS_LIST_LAYOUT_RAW,
                        1, raw_prefix);
 
+out:
        /* clean up */
        free(get_ri.path);
        free(get_ri.name);
        free(get_ri.full_path);
        btrfs_list_free_filter_set(filter_set);
 
-out:
        close_file_or_dir(fd, dirstream1);
-       close_file_or_dir(mntfd, dirstream2);
-       free(mnt);
        free(fullpath);
        return !!ret;
 }

diff --git a/utils.c b/utils.c
index cd3234e..dd2ff9c 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -3171,3 +3171,76 @@ char *get_subvol_name(char *mnt, char *full_path)
 
        return full_path + len;
 }
+
+/*
+ * Returns
+ * <0: Std error
+ * 0: All fine
+ * 1: Error; and error info printed to the terminal. Fixme.
+ * 2: If the fullpath is root tree instead of subvol tree
+ */
+int get_subvol_info(char *fullpath, struct root_info *get_ri)
+{
+       u64 sv_id;
+       int ret = 1;
+       int fd = -1;
+       int mntfd = -1;
+       char *mnt = NULL;
+       char *svpath = NULL;
+       DIR *dirstream1 = NULL;
+       DIR *dirstream2 = NULL;
+
+       ret = test_issubvolume(fullpath);
+       if (ret < 0)
+               return ret;
+       if (!ret) {
+               error("not a subvolume: %s", fullpath);
+               return 1;
+       }
+
+       ret = find_mount_root(fullpath, &mnt);
+       if (ret < 0)
+               return ret;
+       if (ret > 0) {
+               error("%s doesn't belong to btrfs mount point", fullpath);
+               return 1;
+       }
+       ret = 1;
+       svpath = get_subvol_name(mnt, fullpath);
+
+       fd = btrfs_open_dir(fullpath, &dirstream1, 1);
+       if (fd < 0)
+               goto out;
+
+       ret = btrfs_list_get_path_rootid(fd, &sv_id);
+       if (ret) {
+               error("can't get rootid for '%s'", fullpath);
+               goto out;
+       }
+
+       mntfd = btrfs_open_dir(mnt, &dirstream2, 1);
+       if (mntfd < 0)
+               goto out;
+
+       if (sv_id == BTRFS_FS_TREE_OBJECTID) {
+               ret = 2;
+               /*
+                * So that caller may decide if thats an error or just fine.
+                */
+               goto out;
+       }
+
+       memset(get_ri, 0, sizeof(*get_ri));
+       get_ri->root_id = sv_id;
+
+       ret = btrfs_get_subvol(mntfd, get_ri);
+       if (ret)
+               error("can't find '%s': %d", svpath, ret);
+
+out:
+       close_file_or_dir(mntfd, dirstream2);
+       close_file_or_dir(mntfd, dirstream1);
+       free(mnt);
+
+       return ret;
+}

diff --git a/utils.h b/utils.h
index c6395b0..09bd3b3 100644 (file)
--- a/utils.h
+++ b/utils.h
@@ -24,6 +24,7 @@
 #include <dirent.h>
 #include <stdarg.h>
 #include "internal.h"
+#include "btrfs-list.h"
 
 #define BTRFS_MKFS_SYSTEM_GROUP_SIZE (4 * 1024 * 1024)
 #define BTRFS_MKFS_SMALL_VOLUME_SIZE (1024 * 1024 * 1024)
@@ -198,6 +199,7 @@ int test_issubvolume(const char *path);
 int test_isdir(const char *path);
 
 char *get_subvol_name(char *mnt, char *full_path);
+int get_subvol_info(char *fullpath, struct root_info *get_ri);
 
 /*
  * Btrfs minimum size calculation is complicated, it should include at least: