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md: set mddev readonly flag on blkdev BLKROSET ioctl

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When the user sets the block device to readwrite then the mddev should
follow suit.  Otherwise, the BUG_ON in md_write_start() will be set to
trigger.

The reverse direction, setting mddev->ro to match a set readonly
request, can be ignored because the blkdev level readonly flag precludes
the need to have mddev->ro set correctly.  Nevermind the fact that
setting mddev->ro to 1 may fail if the array is in use.

Cc: <stable@kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
Dan Williams
2010-05-12 08:25:37 +10:00
committed by NeilBrown
parent 627a2d3c29
commit e221835046
1 changed files with 29 additions and 0 deletions
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29
drivers/md/md.c
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@@ -5489,6 +5489,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
int err = 0; int err = 0;
void __user *argp = (void __user *)arg; void __user *argp = (void __user *)arg;
mddev_t *mddev = NULL; mddev_t *mddev = NULL;
int ro;
if (!capable(CAP_SYS_ADMIN)) if (!capable(CAP_SYS_ADMIN))
return -EACCES; return -EACCES;
@@ -5624,6 +5625,34 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode,
err = do_md_stop(mddev, 1, 1); err = do_md_stop(mddev, 1, 1);
goto done_unlock; goto done_unlock;
case BLKROSET:
if (get_user(ro, (int __user *)(arg))) {
err = -EFAULT;
goto done_unlock;
}
err = -EINVAL;
/* if the bdev is going readonly the value of mddev->ro
* does not matter, no writes are coming
*/
if (ro)
goto done_unlock;
/* are we are already prepared for writes? */
if (mddev->ro != 1)
goto done_unlock;
/* transitioning to readauto need only happen for
* arrays that call md_write_start
*/
if (mddev->pers) {
err = restart_array(mddev);
if (err == 0) {
mddev->ro = 2;
set_disk_ro(mddev->gendisk, 0);
}
}
goto done_unlock;
} }
/* /*