nilfs2: fix incorrect masking of permission flags for symlinks

stable inclusion
from stable-v5.10.132
commit ea4dbcfb9532a6ac79755e5043d988859961d29c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5YS3T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=ea4dbcfb9532a6ac79755e5043d988859961d29c

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

commit 5924e6ec upstream.

The permission flags of newly created symlinks are wrongly dropped on
nilfs2 with the current umask value even though symlinks should have 777
(rwxrwxrwx) permissions:

 $ umask
 0022
 $ touch file && ln -s file symlink; ls -l file symlink
 -rw-r--r--. 1 root root 0 Jun 23 16:29 file
 lrwxr-xr-x. 1 root root 4 Jun 23 16:29 symlink -> file

This fixes the bug by inserting a missing check that excludes
symlinks.

Link: https://lkml.kernel.org/r/1655974441-5612-1-git-send-email-konishi.ryusuke@gmail.com


Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: Tommy Pettersson <ptp@lysator.liu.se>
Reported-by: Ciprian Craciun <ciprian.craciun@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>