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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/raid1.c
parent11e2ede0228ee0f81ccacd15894908c3bf241f73 (diff)
downloadop-kernel-dev-6bfe0b499082fd3950429017cd8ebf2a6c458aa5.zip
op-kernel-dev-6bfe0b499082fd3950429017cd8ebf2a6c458aa5.tar.gz
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/raid1.c')
-rw-r--r--drivers/md/raid1.c27
1 files changed, 24 insertions, 3 deletions
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 9fd473a..6778b7c 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -773,7 +773,6 @@ static int make_request(struct request_queue *q, struct bio * bio)
r1bio_t *r1_bio;
struct bio *read_bio;
int i, targets = 0, disks;
- mdk_rdev_t *rdev;
struct bitmap *bitmap = mddev->bitmap;
unsigned long flags;
struct bio_list bl;
@@ -781,6 +780,7 @@ static int make_request(struct request_queue *q, struct bio * bio)
const int rw = bio_data_dir(bio);
const int do_sync = bio_sync(bio);
int do_barriers;
+ mdk_rdev_t *blocked_rdev;
/*
* Register the new request and wait if the reconstruction
@@ -862,10 +862,17 @@ static int make_request(struct request_queue *q, struct bio * bio)
first = 0;
}
#endif
+ retry_write:
+ blocked_rdev = NULL;
rcu_read_lock();
for (i = 0; i < disks; i++) {
- if ((rdev=rcu_dereference(conf->mirrors[i].rdev)) != NULL &&
- !test_bit(Faulty, &rdev->flags)) {
+ mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[i].rdev);
+ 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);
if (test_bit(Faulty, &rdev->flags)) {
rdev_dec_pending(rdev, mddev);
@@ -878,6 +885,20 @@ static int make_request(struct request_queue *q, struct bio * bio)
}
rcu_read_unlock();
+ if (unlikely(blocked_rdev)) {
+ /* Wait for this device to become unblocked */
+ int j;
+
+ for (j = 0; j < i; j++)
+ if (r1_bio->bios[j])
+ rdev_dec_pending(conf->mirrors[j].rdev, mddev);
+
+ allow_barrier(conf);
+ md_wait_for_blocked_rdev(blocked_rdev, mddev);
+ wait_barrier(conf);
+ goto retry_write;
+ }
+
BUG_ON(targets == 0); /* we never fail the last device */
if (targets < conf->raid_disks) {
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