[Libguestfs] [PATCH v2 02/11] New API: btrfs_subvolume_get_default

[Richard W.M. Jones]

On Thu, Dec 11, 2014 at 02:11:30PM +0800, Hu Tao wrote:
> btrfs_subvolume_get_default is for getting the default subvolume of
> a btrfs filesystem.
> 
> Signed-off-by: Hu Tao <hutao at cn.fujitsu.com>
> ---
>  daemon/btrfs.c       | 39 +++++++++++++++++++++++++++++++++++++++
>  generator/actions.ml | 18 ++++++++++++++++++
>  src/MAX_PROC_NR      |  2 +-
>  3 files changed, 58 insertions(+), 1 deletion(-)
> 
> diff --git a/daemon/btrfs.c b/daemon/btrfs.c
> index 2e9859d..9f4c5f4 100644
> --- a/daemon/btrfs.c
> +++ b/daemon/btrfs.c
> @@ -553,6 +553,45 @@ do_btrfs_subvolume_set_default (int64_t id, const char *fs)
>    return 0;
>  }
>  
> +int64_t
> +do_btrfs_subvolume_get_default (const mountable_t *fs)
> +{
> +  const size_t MAX_ARGS = 64;
> +  const char *argv[MAX_ARGS];
> +  size_t i = 0;
> +  char *fs_buf = NULL;
> +  CLEANUP_FREE char *err = NULL;
> +  CLEANUP_FREE char *out = NULL;
> +  int r;
> +  int64_t ret = -1;
> +
> +  fs_buf = mount (fs);
> +  if (fs_buf == NULL)
> +    goto error;
> +
> +  ADD_ARG (argv, i, str_btrfs);
> +  ADD_ARG (argv, i, "subvolume");
> +  ADD_ARG (argv, i, "get-default");
> +  ADD_ARG (argv, i, fs_buf);
> +  ADD_ARG (argv, i, NULL);
> +
> +  r = commandv (&out, &err, argv);
> +  if (r == -1) {
> +    reply_with_error ("%s: %s", fs_buf, err);
> +    goto error;
> +  }
> +  if (sscanf (out, "ID %" SCNi64, &ret) != 1) {
> +    reply_with_error ("%s: could not parse subvolume id: %s.", argv[0], out);
> +    ret = -1;
> +    goto error;
> +  }
> +
> +error:
> +  if (fs_buf && umount (fs_buf, fs) != 0)
> +    return -1;
> +  return ret;
> +}
> +
>  int
>  do_btrfs_filesystem_sync (const char *fs)
>  {
> diff --git a/generator/actions.ml b/generator/actions.ml
> index ba97eb3..4e47a02 100644
> --- a/generator/actions.ml
> +++ b/generator/actions.ml
> @@ -12032,6 +12032,24 @@ Set readahead (in 512-byte sectors) for the device.
>  
>  This uses the L<blockdev(8)> command." };
>  
> +  { defaults with
> +    name = "btrfs_subvolume_get_default";
> +    style = RInt64 "id", [Mountable_or_Path "fs"], [];
> +    proc_nr = Some 425;
> +    optional = Some "btrfs"; camel_name = "BTRFSSubvolumeGetDefault";
> +    tests = [
> +      InitPartition, Always, TestResult (
> +        [["mkfs_btrfs"; "/dev/sda1"; ""; ""; "NOARG"; ""; "NOARG"; "NOARG"; ""; ""];
> +         ["btrfs_subvolume_get_default"; "/dev/sda1"]], "ret > 0"), [];
> +      InitPartition, Always, TestResult (
> +        [["mkfs_btrfs"; "/dev/sda1"; ""; ""; "NOARG"; ""; "NOARG"; "NOARG"; ""; ""];
> +         ["mount"; "/dev/sda1"; "/"];
> +         ["btrfs_subvolume_get_default"; "/"]], "ret > 0"), []
> +    ];
> +    shortdesc = "get the default subvolume or snapshot of a filesystem";
> +    longdesc = "\
> +Get the default subvolume or snapshot of a filesystem mounted at C<mountpoint>." };
> +
>  ]
>  
>  (* Non-API meta-commands available only in guestfish.
> diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
> index 9524ef4..5e4a522 100644
> --- a/src/MAX_PROC_NR
> +++ b/src/MAX_PROC_NR
> @@ -1 +1 @@
> -424
> +425

With tests, looks good now.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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