Re: [PATCH] Make inode64 a remountable option

[Dave Chinner <david@xxxxxxxxxxxxx>]

On Thu, Aug 16, 2012 at 03:35:10PM -0300, Carlos Maiolino wrote:
> Actually, there is no reason about why a user must umount and mount a XFS
> filesystem to enable 'inode64' option. So, this patch makes this a remountable
> option.
> 
> Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
> ---
>  fs/xfs/xfs_super.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index bdaf4cb..4dad567 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -120,12 +120,13 @@ mempool_t *xfs_ioend_pool;
>   * in the future, too.
>   */
>  enum {
> -     Opt_barrier, Opt_nobarrier, Opt_err
> +     Opt_barrier, Opt_nobarrier, Opt_inode64, Opt_err
>  };
>  
>  static const match_table_t tokens = {
>       {Opt_barrier, "barrier"},
>       {Opt_nobarrier, "nobarrier"},
> +     {Opt_inode64, "inode64"},
>       {Opt_err, NULL}
>  };
>  
> @@ -1038,11 +1039,15 @@ xfs_fs_remount(
>  {
>       struct xfs_mount        *mp = XFS_M(sb);
>       substring_t             args[MAX_OPT_ARGS];
> +     xfs_sb_t                *sbp = &(mp->m_sb);
> +     xfs_perag_t             *pag;

No need for the xfs_sb_t declaration at all, and pag can be scoped
inside the inner loop. Also, we don't use the typedef versions
anymore...

>       char                    *p;
>       int                     error;
>  
>       while ((p = strsep(&options, ",")) != NULL) {
>               int token;
> +             int agcount = sbp->sb_agcount;
> +             int index = 0;

Similarly, there is no need for the agcount variable, and the first
loop indice is normally named "i".

>  
>               if (!*p)
>                       continue;
> @@ -1055,6 +1060,17 @@ xfs_fs_remount(
>               case Opt_nobarrier:
>                       mp->m_flags &= ~XFS_MOUNT_BARRIER;
>                       break;
> +             case Opt_inode64:
> +
> +                     for (index = 0; index < agcount; index++) {
> +                             pag = xfs_perag_get(mp, index);
> +                             pag->pagi_inodeok = 1;
> +                             xfs_perag_put(pag);
> +                     }

This doesn't clear the pagf_metadata flag that is also set when
inode32 is active to reserve the inode AGs for metadata allocations
only. So the loop needs to look something like:

                        for (i = 0; i < mp->m_sb.sb_agcount; i++) {
                                struct xfs_perag *pag;

                                pag = xfs_perag_get(mp, i);
                                pag->pagi_inodeok = 1;
                                pag->pagf_metadata = 0;
                                xfs_perag_put(pag);
                        }

> +                     mp->m_flags &= ~XFS_MOUNT_32BITINODES;
> +                     mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;

The usual way of clearing multiple flags is like so:

                        mp->m_flags &= ~(XFS_MOUNT_32BITINODES |
                                         XFS_MOUNT_SMALL_INUMS);

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx