Re: [patch] cifs: don't overwrite dentry name in d_revalidate

[Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Merged into cifs-2.6.git

On Thu, Nov 11, 2010 at 1:42 AM, Nick Piggin <npiggin-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org> wrote:
>
> Instead, use fatfs's method for dealing with negative dentries to
> preserve case, rather than overwrite dentry name in d_revalidate, which
> is a bit ugly and also gets in the way of doing lock-free path walking.
>
> Signed-off-by: Nick Piggin <npiggin-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
>
> Index: linux-2.6/fs/cifs/dir.c
> ===================================================================
> --- linux-2.6.orig/fs/cifs/dir.c        2010-11-11 18:05:55.000000000 +1100
> +++ linux-2.6/fs/cifs/dir.c     2010-11-11 18:06:49.000000000 +1100
> @@ -656,22 +656,34 @@ cifs_lookup(struct inode *parent_dir_ino
>  static int
>  cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
>  {
> -       int isValid = 1;
> -
>        if (direntry->d_inode) {
>                if (cifs_revalidate_dentry(direntry))
>                        return 0;
> -       } else {
> -               cFYI(1, "neg dentry 0x%p name = %s",
> -                        direntry, direntry->d_name.name);
> -               if (time_after(jiffies, direntry->d_time + HZ) ||
> -                       !lookupCacheEnabled) {
> -                       d_drop(direntry);
> -                       isValid = 0;
> -               }
> +               else
> +                       return 1;
> +       }
> +
> +       /*
> +        * This may be nfsd (or something), anyway, we can't see the
> +        * intent of this. So, since this can be for creation, drop it.
> +        */
> +       if (!nd)
> +               return 0;
> +
> +       /*
> +        * Drop the negative dentry, in order to make sure to use the
> +        * case sensitive name which is specified by user if this is
> +        * for creation.
> +        */
> +       if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
> +               if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
> +                       return 0;
>        }
>
> -       return isValid;
> +       if (time_after(jiffies, direntry->d_time + HZ) || !lookupCacheEnabled)
> +               return 0;
> +
> +       return 1;
>  }
>
>  /* static int cifs_d_delete(struct dentry *direntry)
> @@ -709,15 +721,8 @@ static int cifs_ci_compare(struct dentry
>        struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
>
>        if ((a->len == b->len) &&
> -           (nls_strnicmp(codepage, a->name, b->name, a->len) == 0)) {
> -               /*
> -                * To preserve case, don't let an existing negative dentry's
> -                * case take precedence.  If a is not a negative dentry, this
> -                * should have no side effects
> -                */
> -               memcpy((void *)a->name, b->name, a->len);
> +           (nls_strnicmp(codepage, a->name, b->name, a->len) == 0))
>                return 0;
> -       }
>        return 1;
>  }
>



--
Thanks,

Steve