On Tue, Nov 30, 2021 at 12:04:48PM +0800, zhanchengbin wrote:
> 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 <tytso@xxxxxxx>
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 <guiyao@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
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
