This patch denies renames and linking of inodes across subvolumes, as it causes disk format corruption.
I guess a long-term goal *might* be to just handle these special cases with care, to allow them by properly handling this case in the implementation, however, I wasn't unable to do that with my limited knowledge. Best regards, Christian Parpart.
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index ff0c359..20a3772 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -2748,6 +2748,10 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir, if (inode->i_nlink == 0) return -ENOENT; + /* do not allow sys_link's with other subvols of the same device */ + if (root->objectid != BTRFS_I(inode)->root->objectid) + return -EPERM; + btrfs_inc_nlink(inode); err = btrfs_check_free_space(root, 1, 0); if (err) @@ -3577,6 +3581,10 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry, return -ENOTEMPTY; } + /* do not allow sys_rename's with other subvols of the same device */ + if (root->objectid != BTRFS_I(new_dir)->root->objectid) + return -EPERM; + ret = btrfs_check_free_space(root, 1, 0); if (ret) goto out_unlock;
