To clarify, commit ea4d53b7b9079fd6e2cc34cf569a993a183bfbd2  does
solve the problem for mounting a disk with the same name as file
  system "tmpfs". However, after mounting it, "ln" command (creating
  a hard link) and "resize2fs" command still report an error.

example:
dev_name="/dev/sdc" (ps: a disk in you self)
mkdir /root/tmp
mkdir /root/mnt
mkfs.ext4 -F -b 1024 -E "resize=10000000" "${dev_name}" 32768
mount -t tmpfs "${dev_name}" /root/tmp
mount "${dev_name}" /root/mnt
ln "${dev_name}" "${dev_name}"-ln
resize2fs "${dev_name}"-ln 6G

You can see the disk is mounted on /root/tmp, but it should be
mounted on /root/mnt actually. I will modify the commit message
  and submit the v2 patch to solve this problem.

在 2021/12/22 4:57, Theodore Ts'o 写道:

On Tue, Nov 30, 2021 at 12:04:48PM +0800, zhanchengbin wrote:

quoted

If there is a tmpfs with the same name as the disk, and mount before the
disk,example:
	/dev/sdd /root/tmp tmpfs rw,seclabel,relatime 0 0
	/dev/sdd /root/mnt ext4 rw,seclabel,relatime 0 0

This should already be fixed e2fsprogs 1.45.5+ via this commit:

commit ea4d53b7b9079fd6e2cc34cf569a993a183bfbd2
Author: Theodore Ts'o [off-list ref]
Date:   Sun Nov 10 12:11:49 2019 -0500

     libext2fs/ismounted.c: check device id in advance to skip false device names
     
     If there is a trickster which tries to use device names as the mount
     device for pseudo-file systems, the resulting /proc/mounts can confuse
     ext2fs_check_mount_point().  (So far as I can tell, there's no good
     reason to do this, but sysadmins do the darnest things.)
     
     An example of this might be the following /proc/mounts excerpt:
     
     /dev/sdb /mnt2 tmpfs rw,relatime 0 0
     /dev/sdb /mnt ext4 rw,relatime 0 0
     
     This is created via "mount -t tmpfs /dev/sdb /mnt2" followed via
     "mount -t ext4 /dev/sdb /mnt".  (Normally, a sane mount of tmpfs would
     use something like "mount -t tmpfs tmpfs /mnt2".)
     
     Fix this by double checking the st_rdev of the claimed mountpoint and
     match it with the dev_t of the device.  (Note that the GNU HURD
     doesn't support st_rdev, so we can't solve this problem for the HURD.)
     
     Reported-by: GuiYao [off-list ref]
     Signed-off-by: Theodore Ts'o [off-list ref]

I've tested via tst_ismounted and I can't replicate the issue you've described.

% cd /build/e2fsprogs-maint/lib/ext2fs
% make tst_ismounted
% sudo ./tst_ismounted /dev/dm-7
Bogus entry in /proc/mounts!  (/dev/dm-7 is not mounted on /root/tmp)
Device /dev/dm-7 reports flags 11
         /dev/dm-7 is apparently in use.
         /dev/dm-7 is mounted.
         /dev/dm-7 is mounted on /root/mnt.

Cheers,

							- Ted
.