The patch titled
md: Fixed refcounting/locking when attempting read error correction in raid10
has been added to the -mm tree. Its filename is
md-fixed-refcounting-locking-when-attempting-read-error-correction-in-raid10.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
From: NeilBrown <neilb@xxxxxxx>
We need to hold a reference to rdevs while reading and writing to attempt to
correct read errors. This reference must be taken under an rcu lock.
Signed-off-by: Neil Brown <neilb@xxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/md/raid10.c | 44 ++++++++++++++++++++++++++++--------------
1 files changed, 30 insertions(+), 14 deletions(-)
diff -puN drivers/md/raid10.c~md-fixed-refcounting-locking-when-attempting-read-error-correction-in-raid10 drivers/md/raid10.c
--- 25/drivers/md/raid10.c~md-fixed-refcounting-locking-when-attempting-read-error-correction-in-raid10 Fri Apr 28 16:39:32 2006
+++ 25-akpm/drivers/md/raid10.c Fri Apr 28 16:39:32 2006
@@ -1407,36 +1407,45 @@ static void raid10d(mddev_t *mddev)
if (s > (PAGE_SIZE>>9))
s = PAGE_SIZE >> 9;
+ rcu_read_lock();
do {
int d = r10_bio->devs[sl].devnum;
- rdev = conf->mirrors[d].rdev;
+ rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
- test_bit(In_sync, &rdev->flags) &&
- sync_page_io(rdev->bdev,
- r10_bio->devs[sl].addr +
- sect + rdev->data_offset,
- s<<9,
- conf->tmppage, READ))
- success = 1;
- else {
- sl++;
- if (sl == conf->copies)
- sl = 0;
+ test_bit(In_sync, &rdev->flags)) {
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
+ success = sync_page_io(rdev->bdev,
+ r10_bio->devs[sl].addr +
+ sect + rdev->data_offset,
+ s<<9,
+ conf->tmppage, READ);
+ rdev_dec_pending(rdev, mddev);
+ rcu_read_lock();
+ if (success)
+ break;
}
+ sl++;
+ if (sl == conf->copies)
+ sl = 0;
} while (!success && sl != r10_bio->read_slot);
+ rcu_read_unlock();
if (success) {
int start = sl;
/* write it back and re-read */
+ rcu_read_lock();
while (sl != r10_bio->read_slot) {
int d;
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
- rdev = conf->mirrors[d].rdev;
+ rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
test_bit(In_sync, &rdev->flags)) {
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
atomic_add(s, &rdev->corrected_errors);
if (sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
@@ -1444,6 +1453,8 @@ static void raid10d(mddev_t *mddev)
s<<9, conf->tmppage, WRITE) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
+ rdev_dec_pending(rdev, mddev);
+ rcu_read_lock();
}
}
sl = start;
@@ -1453,17 +1464,22 @@ static void raid10d(mddev_t *mddev)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
- rdev = conf->mirrors[d].rdev;
+ rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
test_bit(In_sync, &rdev->flags)) {
+ atomic_inc(&rdev->nr_pending);
+ rcu_read_unlock();
if (sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
s<<9, conf->tmppage, READ) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
+ rdev_dec_pending(rdev, mddev);
+ rcu_read_lock();
}
}
+ rcu_read_unlock();
} else {
/* Cannot read from anywhere -- bye bye array */
md_error(mddev, conf->mirrors[r10_bio->devs[r10_bio->read_slot].devnum].rdev);
_
Patches currently in -mm which might be from neilb@xxxxxxx are
md-avoid-oops-when-attempting-to-fix-read-errors-on-raid10.patch
md-fixed-refcounting-locking-when-attempting-read-error-correction-in-raid10.patch
md-change-enotsupp-to-eopnotsupp.patch
md-improve-detection-of-lack-of-barrier-support-in-raid1.patch
md-fix-rdev-nr_pending-count-when-retrying-barrier-requests.patch
fix-dcache-race-during-umount.patch
fix-dcache-race-during-umount-fix.patch
prune_one_dentry-tweaks.patch
remove-softlockup-from-invalidate_mapping_pages.patch
make-address_space_operations-invalidatepage-return-void-reiser4.patch
md-dm-reduce-stack-usage-with-stacked-block-devices.patch
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