ext4: fix check of inode in swap_inode_boot_loader

mainline inclusion
from mainline-next
commit 67a11611
category: bugfix
bugzilla: 5355
CVE: NA
--------------------------------------------------

Before really do swap between inode and boot inode, something need to
check to avoid invalid or not permitted operation, like does this inode
has inline data. But the condition check should be protected by inode
lock to avoid change while swapping. Also some other condition will not
change between swapping, but there has no problem to do this under inode
lock.

Fixes: ee3c859409("ext4: disallow files with EXT4_JOURNAL_DATA_FL ...")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>