Re: [PATCH] fs: Add additional checks for block devices during mount

[Zizhi Wo]

在 2025/7/19 12:17, Al Viro 写道:
> On Sat, Jul 19, 2025 at 10:44:03AM +0800, Zizhi Wo wrote:
>
> > mkfs.ext4 -F /dev/sdb
> > mount /dev/sdb /mnt
> > mknod /dev/test b 8 16    # [sdb 8:16]
> > echo 1 > /sys/block/sdb/device/delete
> > mount /dev/test /mnt1    # -> mount success
> >
> > Therefore, it is necessary to add an extra check. Solve this problem by
> > checking disk_live() in super_s_dev_test().
>
> That smells like a wrong approach...  You are counting upon the failure
> of setup_bdev_super() after the thing is forced on the "no reuse" path,
> and that's too convoluted and brittle...

Since this problem can only occur in the superblock reuse scenario, and
the .test function used in sget_fc() for bdev filesystems is
super_s_dev_test(), I considered adding an additional condition check
within that function.

I'm wondering if there's a better way to handle this...

Thanks,
Zizhi Wo