[issue39460] test_zipfile: test_add_file_after_2107() sometimes fails on Fedora Rawhide 3.x

[Florian Weimer]

Florian Weimer <fweimer at redhat.com> added the comment:

I believe you might be observing an XFS limitation in combination with a Linux VFS bug.

On disk, XFS only supports 32-bit timestamps:

typedef struct xfs_timestamp {
	__be32		t_sec;		/* timestamp seconds */
	__be32		t_nsec;		/* timestamp nanoseconds */
} xfs_timestamp_t;

This is on the roadmap being fixed.

However, the Linux VFS code does not appear to know about this. It caches the full 64-bit value. You only see the truncated value if it is read back from disk:

# touch -t 222201020304 /tmp/t
# ls -l /tmp/t
-rw-r--r--. 1 root root 0 Jan  2  2222 /tmp/t
# echo 3 > /proc/sys/vm/drop_caches 
# ls -l /tmp/t
-rw-r--r--. 1 root root 0 Oct 19  1949 /tmp/t

This is a bug in the Linux VFS layer.

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nosy: +fweimer

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