[PATCH 1/2] md: rcu_read_lock() walk of mddev->disks in md_do_sync()
From: Dan Williams <hidden>
Date: 2009-12-13 04:17:06
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
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: Dan Williams <redacted> --- drivers/md/md.c | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index b182f86..3e8fb67 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c@@ -6342,12 +6342,14 @@ void md_do_sync(mddev_t *mddev) /* recovery follows the physical size of devices */ max_sectors = mddev->dev_sectors; 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 && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) && rdev->recovery_offset < j) j = rdev->recovery_offset; + rcu_read_unlock(); } printk(KERN_INFO "md: %s of RAID array %s\n", desc, mdname(mddev));
@@ -6516,12 +6518,14 @@ void md_do_sync(mddev_t *mddev) } else { if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) 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 && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) && rdev->recovery_offset < mddev->curr_resync) rdev->recovery_offset = mddev->curr_resync; + rcu_read_unlock(); } } set_bit(MD_CHANGE_DEVS, &mddev->flags);