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    SubjectRe: NFS regression in 2.6
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    >>>>> " " == Andries Brouwer <aebr@win.tue.nl> writes:

    > I don't think it will. My analysis of yesterday night was:
    > - no silly rename is done
    > - this is because d_count equals 1
    > - this is because we have two different dentries for the same
    > file
    > - this is caused by the fragment

    > /* If we're doing an exclusive create, optimize away
    > the lookup */ if (nfs_is_exclusive_create(dir, nd))
    > return NULL;

    > in nfs/dir.c. Do you agree?

    No... The above snippet just short-circuits the process of doing an
    RPC call in order to look the file up on the *server*. Doing such a
    lookup would be wrong since it can race with a file creation on
    another NFS client.
    IOW the result of the above 2 lines should be the immediate creation
    of a negative dentry (i.e. one without an inode) that open_namei() can
    pass on to vfs_create().

    When we get to the unlink() call, we shouldn't be hitting nfs_lookup()
    at all unless something somewhere is causing this first dentry to be
    permanently dropped out of the dcache.

    In short the scenario should be that

    - mkstemp() does an open(O_EXCL) -> nfs_lookup() creates hashed
    negative dentry -> nfs_create() then does an O_EXCL call to the
    server and instantiates the dentry.

    - unlink() walks the pathname -> finds the existing dentry using
    cached_lookup() and only calls down to nfs_lookup_revalidate().

    Cheers,
    Trond
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