On Fri, 18 Mar 2011 10:02:07 +0100
Sean Finney <[email protected]> wrote:

Nit:

It's a good idea to prefix the subject with "cifs:" so that when the
patches are committed the subsystem they affect is clear. Makes it
easier for people to scan "git log" by eye.

> The logic behind the expansion of DFS referrals is now extracted from
> cifs_mount into a new static function, expand_dfs_referral.  This will
> reduce duplicate code in upcoming commits.
> ---
>  fs/cifs/connect.c |  105 
> +++++++++++++++++++++++++++++++++++------------------
>  1 files changed, 69 insertions(+), 36 deletions(-)
> 
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 96544a4..7a9b2da 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -2742,6 +2742,57 @@ build_unc_path_to_root(const struct smb_vol 
> *volume_info,
>       full_path[unc_len + cifs_sb->prepathlen] = 0; /* add trailing null */
>       return full_path;
>  }
> +
> +/*
> + * Perform a dfs referral query for a share and (optionally) prefix
> + *
> + * If a referral is found, mount_data will be set to point at a newly
> + * allocated string containing updated options for the submount.
> + * Otherwise it will be left untouched.
> + *
> + * Returns the rc from get_dfs_path to the caller, which can be used to
> + * determine whether there were referrals.
> + */
> +static int
> +expand_dfs_referral(int xid, struct cifs_ses *pSesInfo,
> +                 struct smb_vol *volume_info, struct cifs_sb_info *cifs_sb,
> +                 char **mount_data, int check_prefix)
> +{
> +     int rc;
> +     unsigned int num_referrals = 0;
> +     struct dfs_info3_param *referrals = NULL;
> +     char *full_path = NULL, *ref_path = NULL, *mdata = NULL;
> +
> +     full_path = build_unc_path_to_root(volume_info, cifs_sb);
> +     if (IS_ERR(full_path))
> +             return PTR_ERR(full_path);
> +
> +     /* For DFS paths, skip the first '\' of the UNC */
> +     ref_path = check_prefix ? full_path + 1 : volume_info->UNC + 1;
> +
> +     rc = get_dfs_path(xid, pSesInfo , ref_path, cifs_sb->local_nls,
> +                       &num_referrals, &referrals,
> +                       cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> +
> +     if (!rc && num_referrals > 0) {
> +             char *fake_devname = NULL;
> +
> +             mdata = cifs_compose_mount_options(cifs_sb->mountdata,
> +                                                full_path + 1, referrals,
> +                                                &fake_devname);
> +
> +             free_dfs_info_array(referrals, num_referrals);
> +             kfree(fake_devname);
> +
> +             if (IS_ERR(mdata)) {
> +                     rc = PTR_ERR(mdata);
> +                     mdata = NULL;
> +             }
> +             *mount_data = mdata;
> +     }
> +     kfree(full_path);
> +     return rc;
> +}
>  #endif
>  
>  int
> @@ -2758,10 +2809,19 @@ cifs_mount(struct super_block *sb, struct 
> cifs_sb_info *cifs_sb,
>       char *mount_data = mount_data_global;
>       struct tcon_link *tlink;
>  #ifdef CONFIG_CIFS_DFS_UPCALL
> -     struct dfs_info3_param *referrals = NULL;
> -     unsigned int num_referrals = 0;
>       int referral_walks_count = 0;
>  try_mount_again:
> +
> +     /* cleanup activities if we're chasing a referral */
> +     if (referral_walks_count) {
> +             if (tcon)
> +                     cifs_put_tcon(tcon);
> +             else if (pSesInfo)
> +                     cifs_put_smb_ses(pSesInfo);
> +
> +             cleanup_volume_info(&volume_info);
> +             FreeXid(xid);
> +     }
>  #endif

It's a little ugly to put error handling code at the top like this, but
it's probably ok. We need to do a better job of moving the code out of
the CONFIG_CIFS_DFS_UPCALL macro, but that's really beyond the scope of
this.

>       rc = 0;
>       tcon = NULL;
> @@ -2907,46 +2967,19 @@ remote_path_check:
>               if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) == 0)
>                       convert_delimiter(cifs_sb->prepath,
>                                       CIFS_DIR_SEP(cifs_sb));
> -             full_path = build_unc_path_to_root(volume_info, cifs_sb);
> -             if (IS_ERR(full_path)) {
> -                     rc = PTR_ERR(full_path);
> -                     goto mount_fail_check;
> -             }
>  
> -             cFYI(1, "Getting referral for: %s", full_path);
> -             rc = get_dfs_path(xid, pSesInfo , full_path + 1,
> -                     cifs_sb->local_nls, &num_referrals, &referrals,
> -                     cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
> -             if (!rc && num_referrals > 0) {
> -                     char *fake_devname = NULL;
> -
> -                     if (mount_data != mount_data_global)
> -                             kfree(mount_data);
> -
> -                     mount_data = cifs_compose_mount_options(
> -                                     cifs_sb->mountdata, full_path + 1,
> -                                     referrals, &fake_devname);
> -
> -                     free_dfs_info_array(referrals, num_referrals);
> -                     kfree(fake_devname);
> -                     kfree(full_path);
> -
> -                     if (IS_ERR(mount_data)) {
> -                             rc = PTR_ERR(mount_data);
> -                             mount_data = NULL;
> -                             goto mount_fail_check;
> -                     }
> +             if (mount_data != mount_data_global)
> +                     kfree(mount_data);
>  
> -                     if (tcon)
> -                             cifs_put_tcon(tcon);
> -                     else if (pSesInfo)
> -                             cifs_put_smb_ses(pSesInfo);
> +             rc = expand_dfs_referral(xid, pSesInfo, volume_info, cifs_sb,
> +                                      &mount_data, true);
>  
> -                     cleanup_volume_info(&volume_info);
> +             if (!rc) {
>                       referral_walks_count++;
> -                     FreeXid(xid);
>                       goto try_mount_again;
>               }
> +             mount_data = NULL;
> +             goto mount_fail_check;
>  #else /* No DFS support, return error on mount */
>               rc = -EOPNOTSUPP;
>  #endif

Looks good. Nice work...

Reviewed-by: Jeff Layton <[email protected]>
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