diff options
authorDan Williams <dan.j.williams@intel.com>2008-06-06 18:43:45 +0000
committerChris Wright <chrisw@sous-sol.org>2008-06-09 11:27:05 -0700
commit3c327ceee972ed6c39226d92e7855b6544ae974f (patch)
parent6a2115c0195d0b3aeee20016d628d2ccf0dde640 (diff)
md: do not compute parity unless it is on a failed drive
upstream commit: c337869d95011495fa181536786e74aa2d7ff031 If a block is computed (rather than read) then a check/repair operation may be lead to believe that the data on disk is correct, when infact it isn't. So only compute blocks for failed devices. This issue has been around since at least 2.6.12, but has become harder to hit in recent kernels since most reads bypass the cache. echo repair > /sys/block/mdN/md/sync_action will set the parity blocks to the correct state. Cc: <stable@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 18a1379ed04c..3bd71d9ce352 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1984,6 +1984,7 @@ static int __handle_issuing_new_read_requests5(struct stripe_head *sh,
* have quiesced.
if ((s->uptodate == disks - 1) &&
+ (s->failed && disk_idx == s->failed_num) &&
!test_bit(STRIPE_OP_CHECK, &sh->ops.pending)) {
set_bit(STRIPE_OP_COMPUTE_BLK, &sh->ops.pending);
set_bit(R5_Wantcompute, &dev->flags);
@@ -2069,7 +2070,9 @@ static void handle_issuing_new_read_requests6(struct stripe_head *sh,
/* we would like to get this block, possibly
* by computing it, but we might not be able to
- if (s->uptodate == disks-1) {
+ if ((s->uptodate == disks - 1) &&
+ (s->failed && (i == r6s->failed_num[0] ||
+ i == r6s->failed_num[1]))) {
pr_debug("Computing stripe %llu block %d\n",
(unsigned long long)sh->sector, i);
compute_block_1(sh, i, 0);