From de01dfadf25bf83cfe3d85c163005c4320532658 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 6 Feb 2009 18:02:46 +1100 Subject: [PATCH] md: Ensure an md array never has too many devices. 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 --- drivers/md/md.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 41e2509bf89..4495104f6c9 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -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; -- 2.41.1