On wed, 28 Nov 2012 02:29:17 +0800, Anand jain wrote:
> /*
> @@ -2441,6 +2443,14 @@ static inline bool btrfs_root_readonly(struct btrfs_root *root)
> {
> return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
> }
> +static inline char * btrfs_root_label(struct btrfs_root_item *root_item)
> +{
> + return (root_item->label);
> +}
> +static inline void btrfs_root_set_label(struct btrfs_root_item *root_item, char *val)
> +{
> + memcpy(root_item->label, val, BTRFS_SUBVOL_LABEL_SIZE);
> +}
>
> /* struct btrfs_root_backup */
> BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index e58bd9d..f0b3d9d 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3725,6 +3725,57 @@ static int btrfs_ioctl_set_label(struct btrfs_root *root, void __user *arg)
> return 0;
> }
>
> +static int btrfs_ioctl_subvol_getlabel(struct btrfs_root *root,
> + void __user *arg)
> +{
> + char *label;
> +
> + label = btrfs_root_label(&root->root_item);
> + if (copy_to_user(arg, label, BTRFS_SUBVOL_LABEL_SIZE))
> + return -EFAULT;
we also need lock here.
> + return 0;
> +}
> +
> +static int btrfs_ioctl_subvol_setlabel(struct file *file,
> + void __user *arg)
> +{
> + char label[BTRFS_SUBVOL_LABEL_SIZE+1];
> + struct btrfs_trans_handle *trans;
> + struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
> + struct inode *inode = file->f_path.dentry->d_inode;
> + int ret;
> +
> + if (btrfs_root_readonly(root))
> + return -EROFS;
> +
> + if (!inode_owner_or_capable(inode))
> + return -EACCES;
> +
> + ret = mnt_want_write_file(file);
> + if (ret)
> + return ret;
> +
> + if (copy_from_user(label, arg, BTRFS_SUBVOL_LABEL_SIZE)) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + mutex_lock(&inode->i_mutex);
we should use a lock which belongs to the root not inode.
Thanks
Miao
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