Signed-off-by: Neil Brown <neilb@xxxxxxx>
### Diffstat output
./drivers/md/raid5.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff ./drivers/md/raid5.c~current~ ./drivers/md/raid5.c
--- ./drivers/md/raid5.c~current~ 2006-03-17 18:18:35.000000000 +1100
+++ ./drivers/md/raid5.c 2006-03-17 18:18:44.000000000 +1100
@@ -1766,6 +1766,14 @@ static int make_request(request_queue_t
if (likely(conf->expand_progress == MaxSector))
disks = conf->raid_disks;
else {
+ /* spinlock is needed as expand_progress may be
+ * 64bit on a 32bit platform, and so it might be
+ * possible to see a half-updated value
+ * Ofcourse expand_progress could change after
+ * the lock is dropped, so once we get a reference
+ * to the stripe that we think it is, we will have
+ * to check again.
+ */
spin_lock_irq(&conf->device_lock);
disks = conf->raid_disks;
if (logical_sector >= conf->expand_progress)
@@ -1789,7 +1797,12 @@ static int make_request(request_queue_t
if (sh) {
if (unlikely(conf->expand_progress != MaxSector)) {
/* expansion might have moved on while waiting for a
- * stripe, so we much do the range check again.
+ * stripe, so we must do the range check again.
+ * Expansion could still move past after this
+ * test, but as we are holding a reference to
+ * 'sh', we know that if that happens,
+ * STRIPE_EXPANDING will get set and the expansion
+ * won't proceed until we finish with the stripe.
*/
int must_retry = 0;
spin_lock_irq(&conf->device_lock);
-
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