diff mbox

[RESEND,V4,1/2] Btrfs: Add a new ioctl to get the label of a mounted filesystem

Message ID 50C7F889.5040103@oracle.com (mailing list archive)
State New, archived
Headers show

Commit Message

jeff.liu Dec. 12, 2012, 3:22 a.m. UTC 
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>

---
 fs/btrfs/ioctl.c |   14 ++++++++++++++
 fs/btrfs/ioctl.h |    2 ++
 2 files changed, 16 insertions(+)

Comments

Miao Xie Dec. 12, 2012, 3:50 a.m. UTC | #1 
On Wed, 12 Dec 2012 11:22:49 +0800, Jeff Liu wrote:
> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> 
> ---
>  fs/btrfs/ioctl.c |   14 ++++++++++++++
>  fs/btrfs/ioctl.h |    2 ++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 8fcf9a5..b0a5e17 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3699,6 +3699,18 @@ out:
>  	return ret;
>  }
>  
> +static int btrfs_ioctl_get_fslabel(struct btrfs_root *root, void __user *arg)
> +{
> +	const char *label = root->fs_info->super_copy->label;
> +	int ret;
> +
> +	mutex_lock(&root->fs_info->volume_mutex);
> +	ret = copy_to_user(arg, label, strlen(label));
> +	mutex_unlock(&root->fs_info->volume_mutex);
> +
> +	return ret ? -EFAULT : 0;
> +}
> +
>  long btrfs_ioctl(struct file *file, unsigned int
>  		cmd, unsigned long arg)
>  {
> @@ -3797,6 +3809,8 @@ 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_FSLABEL:
> +		return btrfs_ioctl_get_fslabel(root, argp);
>  	}
>  
>  	return -ENOTTY;
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 731e287..98f896f 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_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \
> +				   char[BTRFS_LABEL_SIZE])
>  #endif
> 

According to the project idea web,
	https://btrfs.wiki.kernel.org/index.php/Project_ideas#Development_notes.2C_please_read

number 53 has been used for the drive swapping commands, so I think we should
choose another one. Maybe 49 is good since the above web says number 50 has been
reserved for set/change label command.
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
jeff.liu Dec. 12, 2012, 4:01 a.m. UTC | #2 
On 12/12/2012 11:50 AM, Miao Xie wrote:
> On Wed, 12 Dec 2012 11:22:49 +0800, Jeff Liu wrote:
>> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
>> Signed-off-by: Anand Jain <anand.jain@oracle.com>
>>
>> ---
>>  fs/btrfs/ioctl.c |   14 ++++++++++++++
>>  fs/btrfs/ioctl.h |    2 ++
>>  2 files changed, 16 insertions(+)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index 8fcf9a5..b0a5e17 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -3699,6 +3699,18 @@ out:
>>  	return ret;
>>  }
>>  
>> +static int btrfs_ioctl_get_fslabel(struct btrfs_root *root, void __user *arg)
>> +{
>> +	const char *label = root->fs_info->super_copy->label;
>> +	int ret;
>> +
>> +	mutex_lock(&root->fs_info->volume_mutex);
>> +	ret = copy_to_user(arg, label, strlen(label));
>> +	mutex_unlock(&root->fs_info->volume_mutex);
>> +
>> +	return ret ? -EFAULT : 0;
>> +}
>> +
>>  long btrfs_ioctl(struct file *file, unsigned int
>>  		cmd, unsigned long arg)
>>  {
>> @@ -3797,6 +3809,8 @@ 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_FSLABEL:
>> +		return btrfs_ioctl_get_fslabel(root, argp);
>>  	}
>>  
>>  	return -ENOTTY;
>> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
>> index 731e287..98f896f 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_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \
>> +				   char[BTRFS_LABEL_SIZE])
>>  #endif
>>
> 
> According to the project idea web,
> 	https://btrfs.wiki.kernel.org/index.php/Project_ideas#Development_notes.2C_please_read
> 
> number 53 has been used for the drive swapping commands, so I think we should
> choose another one. Maybe 49 is good since the above web says number 50 has been
> reserved for set/change label command.
Ok, let's waiting for others comments, I'll follow up the final
confirmation.

Thanks,
-Jeff
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 8fcf9a5..b0a5e17 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3699,6 +3699,18 @@  out:
 	return ret;
 }
 
+static int btrfs_ioctl_get_fslabel(struct btrfs_root *root, void __user *arg)
+{
+	const char *label = root->fs_info->super_copy->label;
+	int ret;
+
+	mutex_lock(&root->fs_info->volume_mutex);
+	ret = copy_to_user(arg, label, strlen(label));
+	mutex_unlock(&root->fs_info->volume_mutex);
+
+	return ret ? -EFAULT : 0;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
 		cmd, unsigned long arg)
 {
@@ -3797,6 +3809,8 @@  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_FSLABEL:
+		return btrfs_ioctl_get_fslabel(root, argp);
 	}
 
 	return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 731e287..98f896f 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_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 53, \
+				   char[BTRFS_LABEL_SIZE])
 #endif