> -----Original Message-----
> From: Williams, Dan J
> Sent: Friday, November 05, 2010 7:01 AM
> To: Czarnowska, Anna
> Cc: Neil Brown; linux-raid@xxxxxxxxxxxxxxx; Neubauer, Wojciech;
> Ciechanowski, Ed; Labun, Marcin; Hawrylewicz Czarnowski, Przemyslaw
> Subject: Re: [PATCH 15/17] Monitor: more accurate size check when
> looking for spares
>
> On 10/29/2010 7:26 AM, Czarnowska, Anna wrote:
> > From 1e6de2b744115224be88da674e633c33934e5cb6 Mon Sep 17 00:00:00
> 2001
> > From: Anna Czarnowska<anna.czarnowska@xxxxxxxxx>
> > Date: Wed, 27 Oct 2010 12:06:42 +0100
> > Subject: [PATCH 15/17] Monitor: more accurate size check when looking
> for spares
> >
> > Signed-off-by: Anna Czarnowska<anna.czarnowska@xxxxxxxxx>
> > ---
> > Monitor.c | 23 ++++++++++++++++++++++-
> > mdadm.h | 1 +
> > super-intel.c | 32 ++++++++++++++++++++++++++++++++
> > 3 files changed, 55 insertions(+), 1 deletions(-)
> >
> > diff --git a/Monitor.c b/Monitor.c
> > index aa2856e..efe36eb 100644
> > --- a/Monitor.c
> > +++ b/Monitor.c
> > @@ -766,6 +766,27 @@ unsigned long long
> min_active_disk_size_in_array(struct state *st)
> > return min;
> > }
> >
> > +unsigned long long min_spare_size_required(struct state *st,
> > + struct supertype *sty)
> > +{
> > + int fd;
> > + unsigned long long rv = 0;
> > +
> > + if (!sty)
> > + return rv;
> > + if (sty->ss->min_acceptable_spare_size) {
> > + fd = open(st->devname, O_RDONLY);
> > + if (fd< 0)
> > + return 0;
> > + sty->ss->load_super(sty, fd, st->devname);
> > + close(fd);
> > + rv = sty->ss->min_acceptable_spare_size(sty);
> > + sty->ss->free_super(sty);
> > + } else
> > + rv = min_active_disk_size_in_array(st);
> > + return rv;
> > +}
> > +
> > struct state *get_parent(struct state *st)
> > {
> > if (is_external(st->metadata_version))
> > @@ -892,7 +913,7 @@ static void spare_sharing(struct state
> *statelist, char *mailaddr,
> > dprintf("no sra for device: %s\n", stp->devname);
> > continue;
> > }
> > - min_size = min_active_disk_size_in_array(st);
> > + min_size = min_spare_size_required(stp, super);
> > if (min_size == 0)
> > continue;
> > for (i = 0; i< stp->total; i++)
> > diff --git a/mdadm.h b/mdadm.h
> > index 4ef3ee5..7047fdf 100644
> > --- a/mdadm.h
> > +++ b/mdadm.h
> > @@ -605,6 +605,7 @@ extern struct superswitch {
> > int (*load_super)(struct supertype *st, int fd, char *devname);
> > struct supertype * (*match_metadata_desc)(char *arg);
> > __u64 (*avail_size)(struct supertype *st, __u64 size);
> > + unsigned long long (*min_acceptable_spare_size)(struct supertype
> *st);
> > int (*add_internal_bitmap)(struct supertype *st, int *chunkp,
> > int delay, int write_behind,
> > unsigned long long size, int may_change, int
> major);
> > diff --git a/super-intel.c b/super-intel.c
> > index bcc202e..77c9d7f 100644
> > --- a/super-intel.c
> > +++ b/super-intel.c
> > @@ -646,6 +646,37 @@ static int is_failed(struct imsm_disk *disk)
> > return (disk->status& FAILED_DISK) == FAILED_DISK;
> > }
> >
> > +/* Return minimum size of a spare that can be used in this array*/
> > +static unsigned long long min_acceptable_spare_size_imsm(struct
> supertype *st)
> > +{
> > + struct intel_super *super = st->sb;
> > + struct dl *dl;
> > + struct extent *e;
> > + int i;
> > + unsigned long long rv = 0;
> > +
> > + if (!super)
> > + return rv;
> > + /* find first active disk in array */
> > + dl = super->disks;
> > + while (dl&& (is_failed(&dl->disk) || dl->index == -1))
> > + dl = dl->next;
> > + if (!dl)
> > + return rv;
> > + /* find last lba used by subarrays */
> > + e = get_extents(super, dl);
> > + if (!e)
> > + return rv;
> > + for (i = 0; e[i].size; i++)
> > + continue;
> > + if (i> 0)
> > + rv = e[i-1].start + e[i-1].size;
> > + free(e);
> > + /* add the amount of space needed for metadata */
> > + rv = rv + MPB_SECTOR_CNT + IMSM_RESERVED_SECTORS;
> > + return rv * 512;
> > +}
> > +
> > #ifndef MDASSEMBLE
> > static __u64 blocks_per_migr_unit(struct imsm_dev *dev);
> >
> > @@ -5629,6 +5660,7 @@ struct superswitch super_imsm = {
> > .update_super = update_super_imsm,
> >
> > .avail_size = avail_size_imsm,
> > + .min_acceptable_spare_size = min_acceptable_spare_size_imsm,
>
> Neil wondered if we can repurpose validate_geometry for this case? It
> is already charged with checking if a disk is suitable to be added to
> an
> array.
I had a look at validate_geometry and I don't think it makes sense to modify it for Monitor.
Validate_geometry is made for Create. When creating container validate_geometry doesn't check much for imsm. When adding to a volume all disks must be already in the same container and have some common free region. We want the check before we move a spare. And the whole spare is free (is not used by any arrays in that container). I think it is better to have smaller functions and use them as building blocks, than make a big function even more complicated for every special case.
Regards
Anna
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