Commit a8bfd4ab authored by jeff.liu's avatar jeff.liu Committed by Josef Bacik

Btrfs: set/change the label of a mounted file system

With this new ioctl(2) BTRFS_IOC_SET_FSLABEL, we can set/change the label of a mounted file system.
Signed-off-by: default avatarJie Liu <jeff.liu@oracle.com>
Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
Reviewed-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Reviewed-by: default avatarGoffredo Baroncelli <kreijack@inwind.it>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.cz>
Reviewed-by: default avatarGoffredo Baroncelli <kreijack@inwind.it>
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
parent 867ab667
...@@ -3936,6 +3936,46 @@ static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg) ...@@ -3936,6 +3936,46 @@ static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
return ret ? -EFAULT : 0; 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) {
pr_err("btrfs: unable to set label with more than %d bytes\n",
BTRFS_LABEL_SIZE - 1);
return -EINVAL;
}
ret = mnt_want_write_file(file);
if (ret)
return ret;
mutex_lock(&root->fs_info->volume_mutex);
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out_unlock;
}
strcpy(super_block->label, label);
ret = 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 long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg) cmd, unsigned long arg)
{ {
...@@ -4038,6 +4078,8 @@ long btrfs_ioctl(struct file *file, unsigned int ...@@ -4038,6 +4078,8 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_dev_replace(root, argp); return btrfs_ioctl_dev_replace(root, argp);
case BTRFS_IOC_GET_FSLABEL: case BTRFS_IOC_GET_FSLABEL:
return btrfs_ioctl_get_fslabel(file, argp); return btrfs_ioctl_get_fslabel(file, argp);
case BTRFS_IOC_SET_FSLABEL:
return btrfs_ioctl_set_fslabel(file, argp);
} }
return -ENOTTY; return -ENOTTY;
......
...@@ -504,6 +504,8 @@ struct btrfs_ioctl_send_args { ...@@ -504,6 +504,8 @@ struct btrfs_ioctl_send_args {
struct btrfs_ioctl_qgroup_limit_args) struct btrfs_ioctl_qgroup_limit_args)
#define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \ #define BTRFS_IOC_GET_FSLABEL _IOR(BTRFS_IOCTL_MAGIC, 49, \
char[BTRFS_LABEL_SIZE]) 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, \ #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
struct btrfs_ioctl_get_dev_stats) struct btrfs_ioctl_get_dev_stats)
#define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \ #define BTRFS_IOC_DEV_REPLACE _IOWR(BTRFS_IOCTL_MAGIC, 53, \
......
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