On Mon, 28 Jun 2010 02:34:33 -0400
Jeff DeFouw <jeffd@xxxxxxx> wrote:
> mdadm --monitor --scan (--oneshot) spins indefinitely without sleeping
> when an "inactive" start-failed raid0 or linear array is found in
> /proc/mdstat. By "start-failed" I mean something attempts to
> (automatically) assemble and start the array, but the array fails to
> start. In my case, an old raid0 is missing a disk. The mdstat parser
> assumes all entries have a personality string, but "inactive" arrays
> don't.
>
> md0 : inactive sda3[0]
> 2915712 blocks
>
> The first disk (sda3[0] in this case) is copied as the level string.
> The mismatch gets the raid0/linear array into the statelist, which is
> immediately rejected by the statelist loop. The rejection occurs
> without marking the mdstat entry as used, so the array is seen as a new
> entry again, the sleep/break is skipped, a new duplicate state is added
> to the statelist, and the loop starts again immediately.
>
> Fixing the parser is simple, but fixing it leads to Monitor ignoring ALL
> inactive arrays discovered by mdstat. This is because the mdstat loop
> requires a level string. If Monitor should process mdstat-discovered
> start-failed arrays (as it currently does), then either the level will
> have to be checked using GET_ARRAY_INFO, or raid0/linear arrays will
> have to be rejected later.
>
> This patch only shows how to fix the parser.
Hi Jeff,
thanks for the patch. I have queued it for the next release.
I think only the parse needs to be fixed. mdadm has never been intended to
monitor inactive arrays because - like linear and raid0 - nothing
interesting can happen to them.
Thanks a lot,
NeilBrown
>
> ---
> mdstat.c | 5 +++--
> 1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mdstat.c b/mdstat.c
> index 4a9f370..fdca877 100644
> --- a/mdstat.c
> +++ b/mdstat.c
> @@ -168,9 +168,10 @@ struct mdstat_ent *mdstat_read(int hold, int start)
> char *eq;
> if (strcmp(w, "active")==0)
> ent->active = 1;
> - else if (strcmp(w, "inactive")==0)
> + else if (strcmp(w, "inactive")==0) {
> ent->active = 0;
> - else if (ent->active >=0 &&
> + in_devs = 1;
> + } else if (ent->active > 0 &&
> ent->level == NULL &&
> w[0] != '(' /*readonly*/) {
> ent->level = strdup(w);
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