From: Jonathan Brassow <[email protected]>
A clear_region function is permitted to block (in practice, rare) but gets
called in rh_update_states() with a spinlock held.
The bits being marked and cleared by the above functions are used
to update the on-disk log, but are never read directly. We can
perform these operations outside the spinlock since the
bits are only changed within one thread viz.
- mark_region in rh_inc()
- clear_region in rh_update_states().
So, we grab the clean_regions list items via list_splice() within the
spinlock and defer clear_region() until we iterate over the list for
deletion - similar to how the recovered_regions list is already handled.
We then move the flush() call down to ensure it encapsulates the changes
which are done by the later calls to clear_region().
Signed-off-by: Jonathan Brassow <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>
---
drivers/md/dm-raid1.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)
Index: linux/drivers/md/dm-raid1.c
===================================================================
--- linux.orig/drivers/md/dm-raid1.c 2007-07-11 21:37:42.000000000 +0100
+++ linux/drivers/md/dm-raid1.c 2007-07-11 21:37:46.000000000 +0100
@@ -378,10 +378,8 @@ static void rh_update_states(struct regi
list_splice(&rh->clean_regions, &clean);
INIT_LIST_HEAD(&rh->clean_regions);
- list_for_each_entry (reg, &clean, list) {
- rh->log->type->clear_region(rh->log, reg->key);
+ list_for_each_entry(reg, &clean, list)
list_del(®->hash_list);
- }
}
if (!list_empty(&rh->recovered_regions)) {
@@ -405,10 +403,12 @@ static void rh_update_states(struct regi
mempool_free(reg, rh->region_pool);
}
- rh->log->type->flush(rh->log);
-
- list_for_each_entry_safe (reg, next, &clean, list)
+ list_for_each_entry_safe(reg, next, &clean, list) {
+ rh->log->type->clear_region(rh->log, reg->key);
mempool_free(reg, rh->region_pool);
+ }
+
+ rh->log->type->flush(rh->log);
}
static void rh_inc(struct region_hash *rh, region_t region)
-
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