Starting with 5.13 we've incorrectly dropped the following sauce patch:
UBUNTU: SAUCE: overlayfs: fix incorrect mnt_id of files opened from map_files
This patch is required to use overlayfs on top of shiftfs and without this patch we may break containers that rely on shiftfs (using zfs/ceph as storage pool w/ shiftfs enabled).
However, we made this patch dependent on AUFS, starting with Jammy we're not enabling AUFS anymore, so this fix becomes a no-op.
So we need to re-introduce this fix with a bit of refactoring to not depend on AUFS.
[Test case]
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)
[Impact]
Starting with 5.13 we've incorrectly dropped the following sauce patch:
UBUNTU: SAUCE: overlayfs: fix incorrect mnt_id of files opened from map_files
This patch is required to use overlayfs on top of shiftfs and without this patch we may break containers that rely on shiftfs (using zfs/ceph as storage pool w/ shiftfs enabled).
However, we made this patch dependent on AUFS, starting with Jammy we're not enabling AUFS anymore, so this fix becomes a no-op.
So we need to re-introduce this fix with a bit of refactoring to not depend on AUFS.
[Test case]
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) proc/self/ map_files/ %s-%s" % (start, end))
test_file2 = open("/
fdinfo1 = open("/ proc/self/ fdinfo/ %d" % test_file1. fileno( )).read( ) proc/self/ fdinfo/ %d" % test_file2. fileno( )).read( )
fdinfo2 = open("/
if fdinfo1 != fdinfo2: test_file1) test_file2)
print("FAIL")
print(
print(fdinfo1)
print(
print(fdinfo2)
sys.exit(1)
print("PASS")
EOF
sudo docker run -it --privileged --rm -v `pwd`:/mnt python python /mnt/test.py
[Fix]
Import the right pieces from AUFS to properly support the fix and get rid of the AUFS dependency across all our kernels.
[Regression potential]
This patch is touching overlayfs, so we may see potential regressions in overlayfs, especially when containers are used.