libct: Enforce nr_inodes=2 to fix Focal mount errors#5353
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LGTM. @lifubang thanks for the quick fix!
I think setting the limit a little higher on the first try is slightly better, but I'm fine doing this for a quick release also. If you change it, there is no need to request a review again :)
| // maskDir mounts a read-only tmpfs on top of the specified path. | ||
| func maskDir(path, mountLabel string) error { | ||
| return mount("tmpfs", path, "tmpfs", unix.MS_RDONLY, label.FormatMountLabel("nr_blocks=1,nr_inodes=1", mountLabel)) | ||
| err := mount("tmpfs", path, "tmpfs", unix.MS_RDONLY, label.FormatMountLabel("nr_blocks=1,nr_inodes=1", mountLabel)) |
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On most kernels `nr_inodes=1` works fine. However, Ubuntu 20.04 (Focal) with the official 5.4 kernel carries a private patch in mm/shmem.c that rejects "nr_inodes<2", so let's keep `nr_inodes=2` here! Signed-off-by: lifubang <lifubang@acmcoder.com>
We don't know whether some kernels will fail with "nr_blocks=1,nr_inodes=2", so let's fall back to the old runc behavior of mounting a tmpfs without these options. Signed-off-by: lifubang <lifubang@acmcoder.com>
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On most kernels
nr_inodes=1works fine. However, Ubuntu 20.04 (Focal) withthe official 5.4 kernel carries a private patch in mm/shmem.c that rejects
"nr_inodes<2", so let's keep
nr_inodes=2here!This PR also add a fall back to legacy runc behavior for uncertain kernel compatibility.
Fix: #5348