Theodore Ts'o reported a v4.19 regression with docker-dropbox:
https://marc.info/?l=linux-fsdevel&m=154070089431116&w=2
"I was rebuilding my dropbox Docker container, and it failed in 4.19
with the following error:
...
dpkg: error: error creating new backup file \
'/var/lib/dpkg/status-old': Invalid cross-device link"
The problem did not reproduce with metacopy feature disabled.
The error was caused by insufficient credentials to set
"trusted.overlay.redirect" xattr on link of a metacopy file.
Reproducer:
echo Y > /sys/module/overlay/parameters/redirect_dir
echo Y > /sys/module/overlay/parameters/metacopy
cd /tmp
mkdir l u w m
chmod 777 l u
touch l/foo
ln l/foo l/link
chmod 666 l/foo
mount -t overlay none -olowerdir=l,upperdir=u,workdir=w m
su fsgqa
ln m/foo m/bar
[ 21.455823] overlayfs: failed to set redirect (-1)
ln: failed to create hard link 'm/bar' => 'm/foo':\
Invalid cross-device link
Reported-by: Theodore Y. Ts'o <[email protected]>
Reported-by: Maciej Zięba <[email protected]>
Fixes: 4120fe64dc ("ovl: Set redirect on upper inode when it is linked")
Cc: <[email protected]> # v4.19
Signed-off-by: Amir Goldstein <[email protected]>
Acked-by: Vivek Goyal <[email protected]>
Signed-off-by: Miklos Szeredi <[email protected]>
Amir Goldstein
91ff20f34e