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Commit 725d6e57 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid10: check In_sync flag in 'enough()'. 



It isn't really enough to check that the rdev is present, we need to
also be sure that the device is still In_sync.

Doing this requires using rcu_dereference to access the rdev, and
holding the rcu_read_lock() to ensure the rdev doesn't disappear while
we look at it.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 635f6416

drivers/md/raid10.c

+11 −4
Original line number Diff line number Diff line
@@ -1633,6 +1633,7 @@ static void status(struct seq_file *seq, struct mddev *mddev) 
static int _enough(struct r10conf *conf, int previous, int ignore)

{

	int first = 0;

	int has_enough = 0;

	int disks, ncopies;

	if (previous) {

		disks = conf->prev.raid_disks;
@@ -1642,21 +1643,27 @@ static int _enough(struct r10conf *conf, int previous, int ignore) 
		ncopies = conf->geo.near_copies;

	}



	rcu_read_lock();

	do {

		int n = conf->copies;

		int cnt = 0;

		int this = first;

		while (n--) {

			if (conf->mirrors[this].rdev &&

			    this != ignore)

			struct md_rdev *rdev;

			if (this != ignore &&

			    (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&

			    test_bit(In_sync, &rdev->flags))

				cnt++;

			this = (this+1) % disks;

		}

		if (cnt == 0)

			return 0;

			goto out;

		first = (first + ncopies) % disks;

	} while (first != 0);

	return 1;

	has_enough = 1;

out:

	rcu_read_unlock();

	return has_enough;

}



static int enough(struct r10conf *conf, int ignore)