Introduce a new ioctl BTRFS_IOC_SET_FSLABEL to change the label of a mounted
file system.
Signed-off-by: Jie Liu <jeff....@oracle.com>
Signed-off-by: Anand Jain <anand.j...@oracle.com>
Cc: Miao Xie <mi...@cn.fujitsu.com>
Cc: Goffredo Baroncelli <kreij...@inwind.it>
---
fs/btrfs/ioctl.c | 39 +++++++++++++++++++++++++++++++++++++++
fs/btrfs/ioctl.h | 2 ++
2 files changed, 41 insertions(+)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6a2488a..2bb037e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3712,6 +3712,43 @@ static int btrfs_ioctl_get_fslabel(struct file *file,
void __user *arg)
return ret ? -EFAULT : 0;
}
+static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
+{
+ struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
+ struct btrfs_super_block *super_block = root->fs_info->super_copy;
+ struct btrfs_trans_handle *trans;
+ char label[BTRFS_LABEL_SIZE];
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (copy_from_user(label, arg, sizeof(label)))
+ return -EFAULT;
+
+ if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE)
+ return -EINVAL;
+
+ ret = mnt_want_write_file(file);
+ if (ret)
+ return ret;
+
+ mutex_lock(&root->fs_info->volume_mutex);
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out_unlock;
+ }
+
+ strcpy(super_block->label, label);
+ btrfs_end_transaction(trans, root);
+
+out_unlock:
+ mutex_unlock(&root->fs_info->volume_mutex);
+ mnt_drop_write_file(file);
+ return ret;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -3812,6 +3849,8 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_qgroup_limit(root, argp);
case BTRFS_IOC_GET_FSLABEL:
return btrfs_ioctl_get_fslabel(file, argp);
+ case BTRFS_IOC_SET_FSLABEL:
+ return btrfs_ioctl_set_fslabel(file, argp);
}
return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 5b2cbef..2abe239 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -453,6 +453,8 @@ struct btrfs_ioctl_send_args {
struct btrfs_ioctl_qgroup_limit_args)
#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \
char[BTRFS_LABEL_SIZE])
+#define BTRFS_IOC_SET_FSLABEL _IOW(BTRFS_IOCTL_MAGIC, 50, \
+ char[BTRFS_LABEL_SIZE])
#define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
struct btrfs_ioctl_get_dev_stats)
#endif
--
1.7.9.5
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