udf_rename(): only access the child content on cross-directory rename

We can't really afford locking the source on same-directory rename;
currently vfs_rename() tries to do that, but it will have to be
changed.  The logics in udf_rename() is lazy and goes looking for
".." in source even in same-directory case.  It's not hard to get
rid of that, leaving that behaviour only for cross-directory case;
that VFS can get locks safely (and will keep doing that after the
coming changes).

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 3508ac484da398bf10d2ef4a5535f10adb1e601b..fac806a7a8d43c2dab34fc335bc780b4f468a357 100644 (file)
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -766,7 +766,7 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
        struct inode *old_inode = d_inode(old_dentry);
        struct inode *new_inode = d_inode(new_dentry);
        struct udf_fileident_iter oiter, niter, diriter;
-       bool has_diriter = false;
+       bool has_diriter = false, is_dir = false;
        int retval;
        struct kernel_lb_addr tloc;
 
@@ -789,6 +789,9 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
                        if (!empty_dir(new_inode))
                                goto out_oiter;
                }
+               is_dir = true;
+       }
+       if (is_dir && old_dir != new_dir) {
                retval = udf_fiiter_find_entry(old_inode, &dotdot_name,
                                               &diriter);
                if (retval == -ENOENT) {
@@ -878,7 +881,9 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir,
                               udf_dir_entry_len(&diriter.fi));
                udf_fiiter_write_fi(&diriter, NULL);
                udf_fiiter_release(&diriter);
+       }
 
+       if (is_dir) {
                inode_dec_link_count(old_dir);
                if (new_inode)
                        inode_dec_link_count(new_inode);