On 11/28/2012 11:05 AM, Miao Xie wrote:
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.
yes. wish memcpy is atomic.
+ 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.
I couldn't find an already defined lock which would exactly fit the purpose here. Do you have any idea ? Thanks, Anand -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
