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

hulk inclusion
category: bugfix
bugzilla: 187685, https://gitee.com/openeuler/kernel/issues/I5VVZX
CVE: NA

--------------------------------

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: NZhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/ubifs/dir.c

@@ -1148,7 +1148,6 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 	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;
 
@@ -1164,6 +1163,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry,
 	 * 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;