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authorNeilBrown <neilb@suse.com>2016-06-02 16:19:53 +1000
committerShaohua Li <shli@fb.com>2016-06-13 11:54:21 -0700
commitf5b67ae86ee317db20c0e10d54f16a0bbbd3207d (patch)
tree8db4539e9c9f05624f2b198ddd1ccce54b281ce6 /drivers/md
parent40cf2123c57928c3ec0626c49bef97ebdbce008e (diff)
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md: be extra careful not to take a reference to a Faulty device.
It is important that we never increment rdev->nr_pending on a Faulty device as ->hot_remove_disk() assumes that once the Faulty flag is visible no code will take a new reference. Some places take a new reference after only check In_sync. This should be safe as the two are changed together. However to make the code more obviously safe, add checks for 'Faulty' as well. Note: the actual rule is: Never increment nr_pending if Faulty is set and Blocked is clear, never clear Faulty, and never set Blocked without holding a reference through nr_pending. fix build error (Shaohua) Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/multipath.c3
-rw-r--r--drivers/md/raid10.c6
-rw-r--r--drivers/md/raid5.c3
3 files changed, 10 insertions, 2 deletions
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 69244de2036b..7eb9972a37e6 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -43,7 +43,8 @@ static int multipath_map (struct mpconf *conf)
rcu_read_lock();
for (i = 0; i < disks; i++) {
struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev);
- if (rdev && test_bit(In_sync, &rdev->flags)) {
+ if (rdev && test_bit(In_sync, &rdev->flags) &&
+ !test_bit(Faulty, &rdev->flags)) {
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
return i;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 526c1d82246e..34facda18e72 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2287,6 +2287,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (rdev &&
test_bit(In_sync, &rdev->flags) &&
+ !test_bit(Faulty, &rdev->flags) &&
is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
&first_bad, &bad_sectors) == 0) {
atomic_inc(&rdev->nr_pending);
@@ -2339,6 +2340,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
+ test_bit(Faulty, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
@@ -2378,6 +2380,7 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
d = r10_bio->devs[sl].devnum;
rdev = rcu_dereference(conf->mirrors[d].rdev);
if (!rdev ||
+ test_bit(Faulty, &rdev->flags) ||
!test_bit(In_sync, &rdev->flags))
continue;
@@ -2953,6 +2956,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
mreplace = rcu_dereference(mirror->replacement);
if ((mrdev == NULL ||
+ test_bit(Faulty, &mrdev->flags) ||
test_bit(In_sync, &mrdev->flags)) &&
(mreplace == NULL ||
test_bit(Faulty, &mreplace->flags))) {
@@ -2971,6 +2975,8 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
rcu_read_unlock();
continue;
}
+ if (mreplace && test_bit(Faulty, &mreplace->flags))
+ mreplace = NULL;
/* Unless we are doing a full sync, or a replacement
* we only need to recover the block if it is set in
* the bitmap
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c07b22e8d946..f6a191aaaa91 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3080,7 +3080,8 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
struct md_rdev *rdev;
rcu_read_lock();
rdev = rcu_dereference(conf->disks[i].rdev);
- if (rdev && test_bit(In_sync, &rdev->flags))
+ if (rdev && test_bit(In_sync, &rdev->flags) &&
+ !test_bit(Faulty, &rdev->flags))
atomic_inc(&rdev->nr_pending);
else
rdev = NULL;