Re: [PATCH] Btrfs: Add get/set label ioctl

Jie Liu
Thu, 30 Aug 2012 06:04:56 -0000

On 08/30/12 13:55, Jie Liu wrote:
> On 08/30/12 13:44, Anand Jain wrote:
>> Jeff,
>>
>>  I don''t find the get label ioctl part unless I am missing
something.
>>  Any idea?
Sorry, I took for granted that this patch has already been merged last
year. :(

To honor your efforts, I''d like to re-send a revised version with set
label only, if other folks like it, you can proceed to
add the get label routine based on it.

Are you happy? :)

Thanks,
-Jeff
> Yes, you''re right, I have not post the get label at that time.
>
> The original patch could be revised with this support easily.
> How about using one structure and one ioctl number for both of them? i.e,
>
> #define BTRFS_IOC_FSLABEL_CTL    _IOW(BTRFS_IOCTL_MAGIC, 50, struct
> btrfs_ioctl_fslabel_ctl_args)
>
> #define BTRFS_FSLABEL_CTL_GET    0
> #define BTRFS_FSLABEL_CTL_SET    1
>
> struct btrfs_ioctl_fslabel_ctl_args {
>         char label[BTRFS_LABEL_SIZE];
>         u32  flags;
> };
>
> so that get/set label from user tools would looks like,
>
> struct btrfs_ioctl_fslabel_ctl_args arg;
> arg.flags = BTRFS_FSLABEL_CTL_GET;  /* get label */
> or
> arg.flags = BTRFS_FSLABEL_CTL_SET; /* set label */
> ....
>
> ioctl(fd, BTRFS_FSLABEL_CTL, &arg);
>
>
> Thanks,
> -Jeff
>> Thxs, -Anand
>>
>>
>> On 30/08/12 09:54, Anand Jain wrote:
>>> Ah. I missed that. Thanks.
>>> So should use your original patch.
>>>
>>> -Anand
>>>
>>> On 29/08/12 17:00, Jie Liu wrote:
>>>> Hi Anand,
>>>>
>>>> I have posted a patch for set label back to last year, which
can be
>>>> found at:
>>>> https://patchwork.kernel.org/patch/1124642/
>>>>
>>>> Besides that, we have discussed to use 50 as the ioctl(2)
number at
>>>> that time.
>>>>
>>>> task assignment in our wiki page:
>>>>
https://btrfs.wiki.kernel.org/index.php/Project_ideas#Set.2Fchange_file_system_label
>>>>
>>>>
>>>> Thanks,
>>>> -Jeff
>>>>
>>>> On 08/29/12 16:46, Anand jain wrote:
>>>>> From: Anand Jain<anand.jain@oracle.com>
>>>>>
>>>>> Signed-off-by: Anand Jain<anand.jain@oracle.com>
>>>>> ---
>>>>> fs/btrfs/ctree.h | 10 ++++++++++
>>>>> fs/btrfs/ioctl.c | 30 ++++++++++++++++++++++++++++++
>>>>> fs/btrfs/ioctl.h | 2 ++
>>>>> 3 files changed, 42 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
>>>>> index 4bab807..eff506f 100644
>>>>> --- a/fs/btrfs/ctree.h
>>>>> +++ b/fs/btrfs/ctree.h
>>>>> @@ -2583,6 +2583,16 @@
BTRFS_SETGET_STACK_FUNCS(super_csum_type,
>>>>> struct btrfs_super_block,
>>>>> BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct
>>>>> btrfs_super_block,
>>>>> cache_generation, 64);
>>>>>
>>>>> +static inline char * btrfs_super_label(struct
btrfs_super_block *s)
>>>>> +{
>>>>> + return s->label;
>>>>> +}
>>>>> +static inline void btrfs_set_super_label(struct
btrfs_super_block *s,
>>>>> + char *val)
>>>>> +{
>>>>> + memcpy(s->label,val,BTRFS_LABEL_SIZE);
>>>>> +}
>>>>> +
>>>>> static inline int btrfs_super_csum_size(struct
btrfs_super_block *s)
>>>>> {
>>>>> int t = btrfs_super_csum_type(s);
>>>>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>>>>> index 7bb7556..b472942 100644
>>>>> --- a/fs/btrfs/ioctl.c
>>>>> +++ b/fs/btrfs/ioctl.c
>>>>> @@ -3687,6 +3687,32 @@ out:
>>>>> return ret;
>>>>> }
>>>>>
>>>>> +static int btrfs_ioctl_get_label(struct btrfs_root *root,
void
>>>>> __user *arg)
>>>>> +{
>>>>> + char *label;
>>>>> + label =
btrfs_super_label(root->fs_info->super_copy);
>>>>> + if (copy_to_user(arg, label, BTRFS_LABEL_SIZE))
>>>>> + return -EFAULT;
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> +static int btrfs_ioctl_set_label(struct btrfs_root *root,
void
>>>>> __user *arg)
>>>>> +{
>>>>> + struct btrfs_trans_handle *trans;
>>>>> + char label[BTRFS_LABEL_SIZE+1];
>>>>> +
>>>>> + if (!capable(CAP_SYS_ADMIN))
>>>>> + return -EPERM;
>>>>> + if (copy_from_user(label, arg, BTRFS_LABEL_SIZE))
>>>>> + return -EFAULT;
>>>>> + label[BTRFS_LABEL_SIZE] = ''\0'';
>>>>> + trans = btrfs_start_transaction(root, 1);
>>>>> + btrfs_set_super_label(root->fs_info->super_copy,
label);
>>>>> + btrfs_commit_transaction(trans, root);
>>>>> +
>>>>> + return 0;
>>>>> +}
>>>>> +
>>>>> long btrfs_ioctl(struct file *file, unsigned int
>>>>> cmd, unsigned long arg)
>>>>> {
>>>>> @@ -3785,6 +3811,10 @@ long btrfs_ioctl(struct file *file,
unsigned
>>>>> int
>>>>> return btrfs_ioctl_qgroup_create(root, argp);
>>>>> case BTRFS_IOC_QGROUP_LIMIT:
>>>>> return btrfs_ioctl_qgroup_limit(root, argp);
>>>>> + case BTRFS_IOC_GET_LABEL:
>>>>> + return btrfs_ioctl_get_label(root, argp);
>>>>> + case BTRFS_IOC_SET_LABEL:
>>>>> + return btrfs_ioctl_set_label(root, argp);
>>>>> }
>>>>>
>>>>> return -ENOTTY;
>>>>> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
>>>>> index 731e287..0c60fcb 100644
>>>>> --- a/fs/btrfs/ioctl.h
>>>>> +++ b/fs/btrfs/ioctl.h
>>>>> @@ -453,4 +453,6 @@ struct btrfs_ioctl_send_args {
>>>>> struct btrfs_ioctl_qgroup_limit_args)
>>>>> #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC,
52, \
>>>>> struct btrfs_ioctl_get_dev_stats)
>>>>> +#define BTRFS_IOC_GET_LABEL _IOR(BTRFS_IOCTL_MAGIC, 53,
__u64)
>>>>> +#define BTRFS_IOC_SET_LABEL _IOW(BTRFS_IOCTL_MAGIC, 54,
__u64)
>>>>> #endif
>>>>
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