Commit 80b48124 authored Sep 27, 2012 by NeilBrown

md/raid10: fix "enough" function for detecting if array is failed.



The 'enough' function is written to work with 'near' arrays only
in that is implicitly assumes that the offset from one 'group' of
devices to the next is the same as the number of copies.
In reality it is the number of 'near' copies.

So change it to make this number explicit.

This bug makes it possible to run arrays without enough drives
present, which is dangerous.
It is appropriate for an -stable kernel, but will almost certainly
need to be modified for some of them.

Cc: stable@vger.kernel.org
Reported-by: Jakub Husák <jakub@gooseman.cz>
Signed-off-by: NeilBrown <neilb@suse.de>

parent cb13ff69

drivers/md/raid10.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -1512,14 +1512,16 @@ static int _enough(struct r10conf conf, struct geom geo, int ignore)
		do {
		int n = conf->copies;
		int cnt = 0;
		int this = first;
		while (n--) {
		if (conf->mirrors[first].rdev &&
		first != ignore)
		if (conf->mirrors[this].rdev &&
		this != ignore)
		cnt++;
		first = (first+1) % geo->raid_disks;
		this = (this+1) % geo->raid_disks;
		}
		if (cnt == 0)
		return 0;
		first = (first + geo->near_copies) % geo->raid_disks;
		} while (first != 0);
		return 1;
		}

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