lkml.org 
[lkml]   [2006]   [Dec]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRE: Finding hardlinks
Date
From
Mikulas Patocka wrote:
>
>>> This sounds like a bug to me. It seems like we should have a one to one
>>> correspondence of filehandle -> inode. In what situations would this not be the
>>> case?
>>
>> Well, the NFS protocol allows that [see rfc1813, p. 21: "If two file handles from
>> the same server are equal, they must refer to the same file, but if they are not
>> equal, no conclusions can be drawn."]
>>
>> As an example, some file systems encode hint information into the filehandle
>> and the hints may change over time, another example is encoding parent
>> information into the filehandle and then handles representing hard links
>> to the same file from different directories will differ.
>
>BTW. how does (or how should?) NFS client deal with cache coherency if
>filehandles for the same file differ?
>

Trond can probably answer this better than me...
As I read it, currently the nfs client matches both the fileid and the
filehandle (in nfs_find_actor). This means that different filehandles
for the same file would result in different inodes :(.
Strictly following the nfs protocol, comparing only the fileid should
be enough IF fileids are indeed unique within the filesystem.
Comparing the filehandle works as a workaround when the exported filesystem
(or the nfs server) violates that. From a user stand point I think that
this should be configurable, probably per mount point.

>Mikulas
>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-12-28 21:11    [W:0.106 / U:0.420 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site