On 10/13/2017 01:37 AM, Shaohua Li wrote:
On Thu, Oct 12, 2017 at 04:30:51PM +0800, Zhilong Liu wrote:
Against the raids which chunk_size is meaningful, the component_size
must be >= chunk_size when require resize. If "new_size < chunk_size"
has required, the "mddev->pers->resize" will set sectors as '0', and
then the raids isn't meaningful any more due to mddev->dev_sectors is
'0'.
Cc: Neil Brown <neilb@xxxxxxxx>
Signed-off-by: Zhilong Liu <zlliu@xxxxxxxx>
Not sure about this, does size 0 disk really harm?
From my site, I think changing the component size as '0' should be avoided.
When resize changing required and new_size < current_chunk_size, such as
raid5:
raid5.c: raid5_resize()
...
7727 sectors &= ~((sector_t)conf->chunk_sectors - 1);
...
'sectors' got '0'.
then:
...
7743 mddev->dev_sectors = sectors;
...
the dev_sectors(the component size) got '0'.
same scenario happens in raid10.
So, it's really not meaningful if changing the raid component_size to
'0', md
should give this scenario a test, otherwise, it's a trouble thing to
restore after
doing such invalid re-size.
Thanks,
-Zhilong
---
drivers/md/raid10.c | 2 ++
drivers/md/raid5.c | 2 ++
2 files changed, 4 insertions(+)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 374df57..f3891f6 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -3871,6 +3871,8 @@ static int raid10_resize(struct mddev *mddev, sector_t sectors)
oldsize = raid10_size(mddev, 0, 0);
size = raid10_size(mddev, sectors, 0);
+ if (size == 0)
+ return -EINVAL;
if (mddev->external_size &&
mddev->array_sectors > size)
return -EINVAL;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 928e24a..768767c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7725,6 +7725,8 @@ static int raid5_resize(struct mddev *mddev, sector_t sectors)
if (conf->log || raid5_has_ppl(conf))
return -EINVAL;
sectors &= ~((sector_t)conf->chunk_sectors - 1);
+ if (sectors == 0)
+ return -EINVAL;
newsize = raid5_size(mddev, sectors, mddev->raid_disks);
if (mddev->external_size &&
mddev->array_sectors > newsize)
--
2.6.6
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