Pozdrawiam,
Łukasz

-----Original Message-----
From: dan.j.williams@gmail.com [mailto:dan.j.williams@gmail.com] On Behalf
Of Dan Williams
Sent: Wednesday, November 30, 2011 3:27 AM
To: Dorau, Lukasz
Cc: neilb@suse.de; linux-raid@vger.kernel.org; Labun, Marcin; Ciechanowski, Ed
Subject: Re: [PATCH] imsm: fix: correct checking newly missing disks

On Mon, Nov 14, 2011 at 6:52 AM, Lukasz Dorau [off-list ref]
wrote:

quoted

The problem occurs when RAID10 array under rebuild
(after one disk fails) is assembled incrementally.
Mdadm tries to start array just after adding the third disk
and the volume is assembled incorrectly (in degraded state).

The cause is that container_enough depends on
newly missing disks which are checked incorrectly now.
They should be checked using always the first map.

Signed-off-by: Lukasz Dorau <redacted>
---
 super-intel.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/super-intel.c b/super-intel.c
index 4ebee78..511a32a 100644
--- a/super-intel.c
+++ b/super-intel.c

@@ -2529,13 +2529,13 @@ static void getinfo_super_imsm(struct supertype

*st, struct mdinfo *info, char *

quoted

               failed = imsm_count_failed(super, dev);
               state = imsm_check_degraded(super, dev, failed);
-               map = get_imsm_map(dev, dev->vol.migr_state);
+               map = get_imsm_map(dev, 0);

               /* any newly missing disks?
                * (catches single-degraded vs double-degraded)
                */
               for (j = 0; j < map->num_members; j++) {
-                       __u32 ord = get_imsm_ord_tbl_ent(dev, i, -1);
+                       __u32 ord = get_imsm_ord_tbl_ent(dev, i, 0);

This looks wrong.  I noticed this when looking over Przemyslaw's patch [1].

map[0] always contains the destination state of the migration so the
most reliable source for looking for out of sync disks is map[1].

I am convinced that the patch is good. 
We are looking for information what was the state of array during migration (before it was stopped), so we have to use map[0].
map[1] contains information about the state of array before migration, which we do not need.

Regards,
Lukasz

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