Messages in this thread | | | Date | Fri, 20 Mar 2015 14:29:14 +0100 | From | Karel Zak <> | Subject | d_path() and overlay fs |
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Hi,
kernel-4.0.0-0.rc4.git1.3.fc23 (I have nothing more recent right now, sorry it the problem is already fixed).
It seems like d_path() kernel function returns nonsenses for overlay fs.
Example:
# mount -t overlay overlay -olowerdir=/mnt/low,upperdir=/mnt/up/data,workdir=/mnt/up/work /mnt/merged # dd if=/dev/zero of=/mnt/merged/image count=1 bs=1MiB
# losetup -f /mnt/merged/image
# cat /sys/block/loop0/loop/backing_file /image
...should be /mnt/merged/image.
drivers/block/loop.c: loop_attr_backing_file_show() uses d_path()
It seems like serious problem because kernel uses d_path() (and friends) on many places to generate path strings for userspace in /proc and /sys and people already use overlay fs in containers.
Another example:
# cat /proc/swaps Filename Type Size Used Priority /dev/sda6 partition 8191996 258308 -1 /image file 1020 0 -2
Karel
-- Karel Zak <kzak@redhat.com> http://karelzak.blogspot.com
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