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Commit 4e59ca7d authored by Dan Williams's avatar Dan Williams Committed by NeilBrown
Browse files

md: rcu_read_lock() walk of mddev->disks in md_do_sync() 



Other walks of this list are either under rcu_read_lock() or the list
mutation lock (mddev_lock()).  This protects against the improbable case of a
disk being removed from the array at the start of md_do_sync().

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 93be75ff

drivers/md/md.c

+6 −2
Original line number Original line Diff line number Diff line
@@ -6526,12 +6526,14 @@ void md_do_sync(mddev_t *mddev) 
		/* recovery follows the physical size of devices */

		/* recovery follows the physical size of devices */

		max_sectors = mddev->dev_sectors;

		max_sectors = mddev->dev_sectors;

		j = MaxSector;

		j = MaxSector;

		list_for_each_entry(rdev, &mddev->disks, same_set)

		rcu_read_lock();

		list_for_each_entry_rcu(rdev, &mddev->disks, same_set)

			if (rdev->raid_disk >= 0 &&

			if (rdev->raid_disk >= 0 &&

			    !test_bit(Faulty, &rdev->flags) &&

			    !test_bit(Faulty, &rdev->flags) &&

			    !test_bit(In_sync, &rdev->flags) &&

			    !test_bit(In_sync, &rdev->flags) &&

			    rdev->recovery_offset < j)

			    rdev->recovery_offset < j)

				j = rdev->recovery_offset;

				j = rdev->recovery_offset;

		rcu_read_unlock();

	}

	}





	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));

	printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
@@ -6701,12 +6703,14 @@ void md_do_sync(mddev_t *mddev) 
		} else {

		} else {

			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))

			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))

				mddev->curr_resync = MaxSector;

				mddev->curr_resync = MaxSector;

			list_for_each_entry(rdev, &mddev->disks, same_set)

			rcu_read_lock();

			list_for_each_entry_rcu(rdev, &mddev->disks, same_set)

				if (rdev->raid_disk >= 0 &&

				if (rdev->raid_disk >= 0 &&

				    !test_bit(Faulty, &rdev->flags) &&

				    !test_bit(Faulty, &rdev->flags) &&

				    !test_bit(In_sync, &rdev->flags) &&

				    !test_bit(In_sync, &rdev->flags) &&

				    rdev->recovery_offset < mddev->curr_resync)

				    rdev->recovery_offset < mddev->curr_resync)

					rdev->recovery_offset = mddev->curr_resync;

					rdev->recovery_offset = mddev->curr_resync;

			rcu_read_unlock();

		}

		}

	}

	}

	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	set_bit(MD_CHANGE_DEVS, &mddev->flags);