Re: [PATCH] fix multilevel diskfilter detection after rev 5024

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 08.06.2013 09:12, Andrey Borzenkov wrote:
> After commit "Fix order to discover ambigouos RAID before discovering
> RAIDs on top of it" diskfilter scans all volumes exactly once. This
> means that only first level is found. Scanning second time will find
> next level etc.
> 
> This means that e.g. MD RAID on top of MD RAID is not found.
Do you mean raid on top of raid on top of raid? Otherwise I don't
understand the problem.
> 
> Change scan to iteratively rescan volume list until nothing new was
> detected (or scan depth exceeded).
> 
> Signed-off-by: Andrey Borzenkov <address@hidden>
> 
> ---
>  ChangeLog                   |  5 +++++
>  grub-core/disk/diskfilter.c | 29 +++++++++++++++++++++--------
>  2 files changed, 26 insertions(+), 8 deletions(-)
> 
> diff --git a/ChangeLog b/ChangeLog
> index 4d8f343..bebcc8a 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2013-06-08  Andrey Borzenkov <address@hidden>
> +
> +     * grub-core/disk/diskfilter.c (scan_devices): Iteratively
> +     rescan diskfilter devices until nothing new is found.
> +
>  2013-06-07  Andrey Borzenkov <address@hidden>
>  
>       * grub-core/script/execute.c (grub_script_execute_sourcecode): Split
> diff --git a/grub-core/disk/diskfilter.c b/grub-core/disk/diskfilter.c
> index c8d267a..0455177 100644
> --- a/grub-core/disk/diskfilter.c
> +++ b/grub-core/disk/diskfilter.c
> @@ -188,6 +188,7 @@ scan_disk (const char *name, int accept_diskfilter)
>    if (!accept_diskfilter && is_valid_diskfilter_name (name))
>      return 0;
>  
> +  /* FIXME do we still need it? It is not called recursively anymore */
>    if (scan_depth > 100)
>      return 0;
Still need it. Consider raid on loopback where underlying OS may call
into diskfilter again.
>  
> @@ -219,6 +220,8 @@ scan_devices (const char *arname)
>    grub_disk_pull_t pull;
>    struct grub_diskfilter_vg *vg;
>    struct grub_diskfilter_lv *lv = NULL;
> +  int scan_depth;
> +  int need_rescan;
>  
>    for (pull = 0; pull < GRUB_DISK_PULL_MAX; pull++)
>      for (p = grub_disk_dev_list; p; p = p->next)
> @@ -231,16 +234,26 @@ scan_devices (const char *arname)
>           return;
>       }
>  
> -  for (vg = array_list; vg; vg = vg->next)
> +  scan_depth = 0;
> +  need_rescan = 1;
> +  while (need_rescan && scan_depth++ < 100)
>      {
> -      if (vg->lvs)
> -     for (lv = vg->lvs; lv; lv = lv->next)
> -       if (!lv->scanned && lv->fullname && lv->became_readable_at)
> -         {
> -           scan_disk (lv->fullname, 1);
> -           lv->scanned = 1;
> -         }
> +      need_rescan = 0;
> +      for (vg = array_list; vg; vg = vg->next)
> +     {
> +       if (vg->lvs)
> +         for (lv = vg->lvs; lv; lv = lv->next)
> +           if (!lv->scanned && lv->fullname && lv->became_readable_at)
> +             {
> +               scan_disk (lv->fullname, 1);
> +               lv->scanned = 1;
> +               need_rescan = 1;
> +             }
> +     }
>      }
> +
> +  if (need_rescan)
> +     grub_error (GRUB_ERR_UNKNOWN_DEVICE, "DISKFILTER scan depth exceeded");
>  }
>  
>  static int
>

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