On Friday August 18, [EMAIL PROTECTED] wrote:
The atomic_add (and any other access to an rdev, for that matter) needs
to be guarded by a NULL check, I think.
Neil, does that sound right?
Yes. Thanks for doing the analysis.
However after looking closely through the code, I think the atomic_inc
really is in the wrong place.
We are increasing 'corrected_errors' before we try to write out the
good data. We should really wait until after reading back the good
data. So rather than just protecting the atomic_inc with if(dev),
I'm going to move it several lines down.
And while I'm at it, there seem to be several place that reference
-rdev that could be cleaned up.
So I'm thinking of something like the following against -mm
I'll make a smaller patch for -stable.
Thanks,
NeilBrown
Signed-off-by: Neil Brown [EMAIL PROTECTED]
### Diffstat output
./drivers/md/raid1.c | 55 +++
1 file changed, 34 insertions(+), 21 deletions(-)
diff .prev/drivers/md/raid1.c ./drivers/md/raid1.c
--- .prev/drivers/md/raid1.c2006-08-15 13:33:02.0 +1000
+++ ./drivers/md/raid1.c2006-08-21 09:40:41.0 +1000
@@ -930,10 +930,13 @@ static void status(struct seq_file *seq,
seq_printf(seq, [%d/%d] [, conf-raid_disks,
conf-raid_disks - mddev-degraded);
- for (i = 0; i conf-raid_disks; i++)
+ rcu_read_lock();
+ for (i = 0; i conf-raid_disks; i++) {
+ mdk_rdev_t *rdev = rcu_dereference(conf-mirrors[i].rdev);
seq_printf(seq, %s,
- conf-mirrors[i].rdev
- test_bit(In_sync, conf-mirrors[i].rdev-flags)
? U : _);
+ rdev test_bit(In_sync, rdev-flags) ? U : _);
+ }
+ rcu_read_unlock();
seq_printf(seq, ]);
}
@@ -976,7 +979,6 @@ static void error(mddev_t *mddev, mdk_rd
static void print_conf(conf_t *conf)
{
int i;
- mirror_info_t *tmp;
printk(RAID1 conf printout:\n);
if (!conf) {
@@ -986,14 +988,17 @@ static void print_conf(conf_t *conf)
printk( --- wd:%d rd:%d\n, conf-raid_disks - conf-mddev-degraded,
conf-raid_disks);
+ rcu_read_lock();
for (i = 0; i conf-raid_disks; i++) {
char b[BDEVNAME_SIZE];
- tmp = conf-mirrors + i;
- if (tmp-rdev)
+ mdk_rdev_t *rdev = rcu_dereference(conf-mirrors[i].rdev);
+ if (rdev)
printk( disk %d, wo:%d, o:%d, dev:%s\n,
- i, !test_bit(In_sync, tmp-rdev-flags),
!test_bit(Faulty, tmp-rdev-flags),
- bdevname(tmp-rdev-bdev,b));
+ i, !test_bit(In_sync, rdev-flags),
+ !test_bit(Faulty, rdev-flags),
+ bdevname(rdev-bdev,b));
}
+ rcu_read_unlock();
}
static void close_sync(conf_t *conf)
@@ -1009,17 +1014,17 @@ static int raid1_spare_active(mddev_t *m
{
int i;
conf_t *conf = mddev-private;
- mirror_info_t *tmp;
/*
* Find all failed disks within the RAID1 configuration
-* and mark them readable
+* and mark them readable.
+* Called under mddev lock, so rcu protection not needed.
*/
for (i = 0; i conf-raid_disks; i++) {
- tmp = conf-mirrors + i;
- if (tmp-rdev
-!test_bit(Faulty, tmp-rdev-flags)
-!test_and_set_bit(In_sync, tmp-rdev-flags)) {
+ mdk_rdev_t *rdev = conf-mirrors[i].rdev;
+ if (rdev
+!test_bit(Faulty, rdev-flags)
+!test_and_set_bit(In_sync, rdev-flags)) {
unsigned long flags;
spin_lock_irqsave(conf-device_lock, flags);
mddev-degraded--;
@@ -1239,7 +1244,7 @@ static void sync_request_write(mddev_t *
/* ouch - failed to read all of that.
* Try some synchronous reads of other devices to get
* good data, much like with normal read errors. Only
-* read into the pages we already have so they we don't
+* read into the pages we already have so we don't
* need to re-issue the read request.
* We don't need to freeze the array, because being in an
* active sync request, there is no normal IO, and
@@ -1259,6 +1264,10 @@ static void sync_request_write(mddev_t *
s = PAGE_SIZE 9;
do {
if (r1_bio-bios[d]-bi_end_io ==
end_sync_read) {
+ /* No rcu protection needed here devices
+* can only be removed when no resync
is
+
