Public bug reported:
[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)
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
[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.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Affects: linux (Ubuntu Focal)
Importance: Undecided
Status: New
** Affects: linux (Ubuntu Jammy)
Importance: Undecided
Status: New
** Affects: linux (Ubuntu Kinetic)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Focal)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Jammy)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Kinetic)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1983640
Title:
refactoring of overlayfs fix to report the right mnt_id of files
opened from map_files
Status in linux package in Ubuntu:
New
Status in linux source package in Focal:
New
Status in linux source package in Jammy:
New
Status in linux source package in Kinetic:
New
Bug description:
[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)
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
[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.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1983640/+subscriptions
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