On Thu, Apr 13, 2017 at 08:53:48AM +1000, Neil Brown wrote:
>
> 1/ If an array has any read-only devices when it is started,
> the array itself must be read-only
> 2/ A read-only device cannot be added to an array after it is
> started.
> 3/ Setting an array to read-write should not succeed
> if any member devices are read-only
Didn't get these. We call md_import_device() first to open under layer disk. We
always use FMOD_READ|FMOD_WRITE to open the disk. So if the disk is ro,
md_import_device should fail, we don't add the disk to the array. Why would we
have such issues?
Thanks,
Shaohua
> Reported-and-Tested-by: Nanda Kishore Chinnaram <Nanda_Kishore_Chinna@xxxxxxxx>
> Signed-off-by: NeilBrown <neilb@xxxxxxxx>
> ---
> drivers/md/md.c | 41 ++++++++++++++++++++++++++---------------
> 1 file changed, 26 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 22894303d335..9fe930109012 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -2093,6 +2093,10 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
> if (find_rdev(mddev, rdev->bdev->bd_dev))
> return -EEXIST;
>
> + if ((bdev_read_only(rdev->bdev) || bdev_read_only(rdev->meta_bdev)) &&
> + mddev->pers)
> + return -EROFS;
> +
> /* make sure rdev->sectors exceeds mddev->dev_sectors */
> if (!test_bit(Journal, &rdev->flags) &&
> rdev->sectors &&
> @@ -5345,6 +5349,13 @@ int md_run(struct mddev *mddev)
> continue;
> sync_blockdev(rdev->bdev);
> invalidate_bdev(rdev->bdev);
> + if (mddev->ro != 1 &&
> + (bdev_read_only(rdev->bdev) ||
> + bdev_read_only(rdev->meta_bdev))) {
> + mddev->ro = 1;
> + if (mddev->gendisk)
> + set_disk_ro(mddev->gendisk, 1);
> + }
>
> /* perform some consistency tests on the device.
> * We don't want the data to overlap the metadata,
> @@ -5569,6 +5580,9 @@ static int do_md_run(struct mddev *mddev)
> static int restart_array(struct mddev *mddev)
> {
> struct gendisk *disk = mddev->gendisk;
> + struct md_rdev *rdev;
> + bool has_journal = false;
> + bool has_readonly = false;
>
> /* Complain if it has no devices */
> if (list_empty(&mddev->disks))
> @@ -5577,24 +5591,21 @@ static int restart_array(struct mddev *mddev)
> return -EINVAL;
> if (!mddev->ro)
> return -EBUSY;
> - if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
> - struct md_rdev *rdev;
> - bool has_journal = false;
> -
> - rcu_read_lock();
> - rdev_for_each_rcu(rdev, mddev) {
> - if (test_bit(Journal, &rdev->flags) &&
> - !test_bit(Faulty, &rdev->flags)) {
> - has_journal = true;
> - break;
> - }
> - }
> - rcu_read_unlock();
>
> + rcu_read_lock();
> + rdev_for_each_rcu(rdev, mddev) {
> + if (test_bit(Journal, &rdev->flags) &&
> + !test_bit(Faulty, &rdev->flags))
> + has_journal = true;
> + if (bdev_read_only(rdev->bdev))
> + has_readonly = true;
> + }
> + rcu_read_unlock();
> + if (test_bit(MD_HAS_JOURNAL, &mddev->flags) && !has_journal)
> /* Don't restart rw with journal missing/faulty */
> - if (!has_journal)
> return -EINVAL;
> - }
> + if (has_readonly)
> + return -EROFS;
>
> mddev->safemode = 0;
> mddev->ro = 0;
> --
> 2.12.2
>
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