ubifs: Rectify space budget for ubifs_symlink() if symlink is encrypted

Fix bad space budget when symlink file is encrypted. Bad space budget
may let make_reservation() return with -ENOSPC, which could turn ubifs
to read-only mode in do_writepage() process.

Fetch a reproducer in [Link].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216490
Fixes: ca7f85be ("ubifs: Add support for encrypted symlinks")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/dir.c

@@ -1151,7 +1151,6 @@ static int ubifs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 	int err, sz_change, len = strlen(symname);
 	struct fscrypt_str disk_link;
 	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
-					.new_ino_d = ALIGN(len, 8),
 					.dirtied_ino = 1 };
 	struct fscrypt_name nm;
 
@@ -1167,6 +1166,7 @@ static int ubifs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 	 * Budget request settings: new inode, new direntry and changing parent
 	 * directory inode.
 	 */
+	req.new_ino_d = ALIGN(disk_link.len - 1, 8);
 	err = ubifs_budget_space(c, &req);
 	if (err)
 		return err;