Re: [PATCH] Reinstantiating stale inodes

[Steve Dickson <SteveD@redhat.com>]

Trond Myklebust wrote:

>On Fri, 2004-04-23 at 10:48, Lever, Charles wrote:
>  
>
>>there appears to be a real problem when restoring from a backup,
>>or using rsync.  the file size and the mtime stay precisely the
>>same, but the file handle changes.  i'm not sure anything can be
>>done about this in NFSv2/3?
>>    
>>
>
>The only way to distinguish the two is to replace the use of the mtime
>with the ctime in nfs_check_verifier() and friends.
>  
>
Again.. this was the first place I looked... And I just can't figure how
to use NFS_CACHE_CTIME() in any meaningful calculation...

>Under ordinary circumstances, the mtime and ctime should be more or less
>identical, 
>
In this particular case they aren't because the server explicitly
maintains the "old" mtime and since mtime does not change we'll never
get the new ctime...

>so I'm not sure why Steve was seeing extra revalidations when
>he was running the Connectathon suite. Were you perhaps changing the
>algorithm in nfs_refresh_inode() instead, Steve?
>  
>
A very keen observation... Yes, when I introduced ctime into the valid or
not valid calculation, the getattrs (i.e revalidations) but even more
surprising (at least to me) was the number of reads sky rocked when
I ran the cthon tests...

SteveD.


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