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md: Ensure an md array never has too many devices.

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Each different metadata format supported by md supports a
different maximum number of devices.
We really should be enforcing this maximum in the kernel, but
we aren't quite doing that properly.

We currently only enforce it at the 'hot_add' point, which is an
older interface which is not used by current userspace.

We need to also enforce it at 'add_new_disk' time for active arrays
and at 'do_md_run' time when starting a new array.

So move the test from 'hot_add' into 'bind_rdev_to_array' which is
called from both 'hot_add' and 'add_new_disk, and add a new
test in 'analyse_sbs' which is called from 'do_md_run'.

This bug (or missing feature) has been around "forever" and so
the patch is suitable for any -stable that is currently maintained.

Cc: stable@kernel.org

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2009-02-06 18:02:46 +11:00
parent 852c8bf484
commit de01dfadf2
1 changed files with 14 additions and 10 deletions
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24
drivers/md/md.c
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@ -1481,6 +1481,11 @@ static int bind_rdev_to_array(mdk_rdev_t * rdev, mddev_t * mddev)
if (find_rdev_nr(mddev, rdev->desc_nr))
return -EBUSY;
}
if (mddev->max_disks && rdev->desc_nr >= mddev->max_disks) {
printk(KERN_WARNING "md: %s: array is limited to %d devices\n",
mdname(mddev), mddev->max_disks);
return -EBUSY;
}
bdevname(rdev->bdev,b);
while ( (s=strchr(b, '/')) != NULL)
*s = '!';
@ -2441,6 +2446,15 @@ static void analyze_sbs(mddev_t * mddev)
i = 0;
rdev_for_each(rdev, tmp, mddev) {
if (rdev->desc_nr >= mddev->max_disks ||
i > mddev->max_disks) {
printk(KERN_WARNING
"md: %s: %s: only %d devices permitted\n",
mdname(mddev), bdevname(rdev->bdev, b),
mddev->max_disks);
kick_rdev_from_array(rdev);
continue;
}
if (rdev != freshest)
if (super_types[mddev->major_version].
validate_super(mddev, rdev)) {
@ -4614,13 +4628,6 @@ static int hot_add_disk(mddev_t * mddev, dev_t dev)
* noticed in interrupt contexts ...
*/
if (rdev->desc_nr == mddev->max_disks) {
printk(KERN_WARNING "%s: can not hot-add to full array!\n",
mdname(mddev));
err = -EBUSY;
goto abort_unbind_export;
}
rdev->raid_disk = -1;
md_update_sb(mddev, 1);
@ -4634,9 +4641,6 @@ static int hot_add_disk(mddev_t * mddev, dev_t dev)
md_new_event(mddev);
return 0;
abort_unbind_export:
unbind_rdev_from_array(rdev);
abort_export:
export_rdev(rdev);
return err;