kernel-unstable: Adds label manipulate ioctl

This patch adds two IOCTLs to allow for changing of the label with the file system mounted.

---

diff -r 447f15493ff8 ioctl.c
@@ -749,6 +749,53 @@

	return ret;
}

+long btrfs_ioctl_set_label(struct btrfs_root *root, void __user *arg) +{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_ioctl_label_args *label_args;
+ int ret = 0;
+
+ label_args = kmalloc(sizeof(*label_args), GFP_NOFS);
+
+ if (!label_args)
+ return -ENOMEM;
+
+ if (copy_from_user(label_args, arg, sizeof(*label_args)))
+ {
+ ret = -EFAULT;
+ } else
+ {
+ /* Everything looks good, so lets do a label change */
+ label_args->name[BTRFS_LABEL_SIZE] = 0x00;
+ trans = btrfs_start_transaction(root, 1);
+ strncpy(root->fs_info->super_copy.label, label_args->name, BTRFS_LABEL_SIZE);
+ btrfs_commit_transaction(trans, root);
+ }
+
+ kfree(label_args);
+ return ret;
+}
+
+long btrfs_ioctl_get_label(struct btrfs_root *root, void __user *arg) +{
+ struct btrfs_ioctl_label_args *label_args;
+ int ret = 0;
+
+ label_args = kmalloc(sizeof(*label_args), GFP_NOFS);
+
+ if (!label_args)
+ return -ENOMEM;
+
+ strncpy(label_args->name, root->fs_info->super_copy.label, BTRFS_LABEL_SIZE);
+ if (copy_to_user(arg, label_args, sizeof(*label_args)))
+ {
+ ret = -EFAULT;
+ }
+
+ kfree(label_args);
+ return ret;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -773,6 +820,10 @@

		return btrfs_ioctl_trans_start(file);
	case BTRFS_IOC_TRANS_END:
		return btrfs_ioctl_trans_end(file);
+	case BTRFS_IOC_SET_LABEL:
+		return btrfs_ioctl_set_label(root, (void __user *)arg);
+	case BTRFS_IOC_GET_LABEL:
+		return btrfs_ioctl_get_label(root, (void __user *)arg);
	case BTRFS_IOC_SYNC:
		btrfs_start_delalloc_inodes(root);
		btrfs_sync_fs(file->f_dentry->d_sb, 1);

diff -r 447f15493ff8 ioctl.h
@@ -19,6 +19,7 @@

#ifndef __IOCTL_
#define __IOCTL_
#include <linux/ioctl.h>
+#include "ctree.h"

#define BTRFS_IOCTL_MAGIC 0x94
#define BTRFS_VOL_NAME_MAX 255
@@ -26,6 +27,10 @@

struct btrfs_ioctl_vol_args {
	char name[BTRFS_PATH_NAME_MAX + 1];

+};
+
+struct btrfs_ioctl_label_args {
+ char name[BTRFS_LABEL_SIZE + 1];
};

#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
@@ -52,4 +57,10 @@
#define BTRFS_IOC_BALANCE _IOW(BTRFS_IOCTL_MAGIC, 12, \
struct btrfs_ioctl_vol_args)

+/* Used to set and get the current volume label */
+#define BTRFS_IOC_SET_LABEL _IOW(BTRFS_IOCTL_MAGIC, 13, \
+ struct btrfs_ioctl_label_args)
+#define BTRFS_IOC_GET_LABEL _IOW(BTRFS_IOCTL_MAGIC, 14, \
+ struct btrfs_ioctl_label_args)
+
#endif