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authorDan Williams <dan.j.williams@intel.com>2008-04-30 00:52:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:33 -0700
commit6bfe0b499082fd3950429017cd8ebf2a6c458aa5 (patch)
tree81476cf7f7ddbea135bdb93729e0bffae0e7c163 /drivers/md/raid10.c
parent11e2ede0228ee0f81ccacd15894908c3bf241f73 (diff)
md: support blocking writes to an array on device failure
Allows a userspace metadata handler to take action upon detecting a device failure. Based on an original patch by Neil Brown. Changes: -added blocked_wait waitqueue to rdev -don't qualify Blocked with Faulty always let userspace block writes -added md_wait_for_blocked_rdev to wait for the block device to be clear, if userspace misses the notification another one is sent every 5 seconds -set MD_RECOVERY_NEEDED after clearing "blocked" -kill DoBlock flag, just test mddev->external 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>
Diffstat (limited to 'drivers/md/raid10.c')
-rw-r--r--drivers/md/raid10.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 1e96aa3ff51..5938fa96292 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -790,6 +790,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
const int do_sync = bio_sync(bio);
struct bio_list bl;
unsigned long flags;
+ mdk_rdev_t *blocked_rdev;
if (unlikely(bio_barrier(bio))) {
bio_endio(bio, -EOPNOTSUPP);
@@ -879,17 +880,23 @@ static int make_request(struct request_queue *q, struct bio * bio)
/*
* WRITE:
*/
- /* first select target devices under spinlock and
+ /* first select target devices under rcu_lock and
* inc refcount on their rdev. Record them by setting
* bios[x] to bio
*/
raid10_find_phys(conf, r10_bio);
+ retry_write:
+ blocked_rdev = 0;
rcu_read_lock();
for (i = 0; i < conf->copies; i++) {
int d = r10_bio->devs[i].devnum;
mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev);
- if (rdev &&
- !test_bit(Faulty, &rdev->flags)) {
+ if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
+ atomic_inc(&rdev->nr_pending);
+ blocked_rdev = rdev;
+ break;
+ }
+ if (rdev && !test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
r10_bio->devs[i].bio = bio;
} else {
@@ -899,6 +906,22 @@ static int make_request(struct request_queue *q, struct bio * bio)
}
rcu_read_unlock();
+ if (unlikely(blocked_rdev)) {
+ /* Have to wait for this device to get unblocked, then retry */
+ int j;
+ int d;
+
+ for (j = 0; j < i; j++)
+ if (r10_bio->devs[j].bio) {
+ d = r10_bio->devs[j].devnum;
+ rdev_dec_pending(conf->mirrors[d].rdev, mddev);
+ }
+ allow_barrier(conf);
+ md_wait_for_blocked_rdev(blocked_rdev, mddev);
+ wait_barrier(conf);
+ goto retry_write;
+ }
+
atomic_set(&r10_bio->remaining, 0);
bio_list_init(&bl);