UBUNTU: SAUCE: overlayfs: fix incorrect mnt_id of files opened from map_files
BugLink: https://bugs.launchpad.net/bugs/1857257
The hack was introduced in ("UBUNTU: SAUCE: overlayfs: allow with
shiftfs as underlay") and it broke checkpoint/restore of docker
contains:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/
1857257
The following script can be used to trigger the issue:
#!/bin/bash
cat > test.py << EOF
import sys
f = open("/proc/self/maps")
for l in f.readlines():
if "python" not in l:
continue
print(l)
s = l.split()
start, end = s[0].split("-")
fname = s[-1]
print(start, end, fname)
break
else:
sys.exit(1)
test_file1 = open(fname)
test_file2 = open("/proc/self/map_files/%s-%s" % (start, end))
fdinfo1 = open("/proc/self/fdinfo/%d" % test_file1.fileno()).read()
fdinfo2 = open("/proc/self/fdinfo/%d" % test_file2.fileno()).read()
if fdinfo1 != fdinfo2:
print("FAIL")
print(test_file1)
print(fdinfo1)
print(test_file2)
print(fdinfo2)
sys.exit(1)
print("PASS")
EOF
sudo docker run -it --privileged --rm -v `pwd`:/mnt python python /mnt/test.py
Thanks to Andrei Vagin for the reproducer and investigation of this problem.
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Adrian Reber <areber@redhat.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Fixes: d24b8a5 ("UBUNTU: SAUCE: overlayfs: allow with shiftfs as underlay")
Signed-off-by: Alexander Mikhalitsyn <alexander@mihalicyn.com>
[ saf: resolve conflicts with "ovl: fix reference counting in ovl_mmap
error path" ]
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>