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    SubjectRe: explicit dcache <-> user-space cache coherency, sys_mark_dir_clean(), O_CLEAN
    Hi!

    > generation counters are problematic if they are not persistent. But
    > there's a pretty natural persistent 'generation counter' which could be
    > used for Samba's purpose: the mtime of the directory. The problem right
    > now is that it doesnt have enough resolution to be a true unique
    > generation counter. But having high-resolution mtime is a goal anyway.
    >
    > XFS is one filesystem that has high-resolution mtime:
    >
    > typedef struct xfs_timestamp {
    > __int32_t t_sec; /* timestamp seconds */
    > __int32_t t_nsec; /* timestamp nanoseconds */
    > } xfs_timestamp_t;
    >
    > monotonity is important: two successive directory operations to not be
    > possible within the same nanosecond. This is not possible with current
    > hardware - but how about future hardware? Can we make an assumption like
    > this?

    Does not ndelay(1) if samba notices mtime is too young in the samba code
    fix that?
    --
    64 bytes from 195.113.31.123: icmp_seq=28 ttl=51 time=448769.1 ms

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