dm-dmio-retry-barriers.patch
If -EOPNOTSUPP was returned and the request was a barrier request, retry it
without barrier.
Retry all regions (if there was just one region returning -EOPNOTSUPP), for
now, barriers are submitted only for 1-region requests, so it doesn't matter.
In the future, this can be fine-grained to retry only -EOPNOTSUPPed regions.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-io.c | 6 ++++++
1 file changed, 6 insertions(+)
Index: linux-2.6.29-rc1-devel/drivers/md/dm-io.c
===================================================================
--- linux-2.6.29-rc1-devel.orig/drivers/md/dm-io.c 2009-01-22 21:09:28.000000000 +0100
+++ linux-2.6.29-rc1-devel/drivers/md/dm-io.c 2009-01-22 21:09:37.000000000 +0100
@@ -364,6 +364,7 @@ static int sync_io(struct dm_io_client *
return -EIO;
}
+retry:
io.error_bits = 0;
io.eopnotsupp_bits = 0;
atomic_set(&io.count, 1); /* see dispatch_io() */
@@ -382,6 +383,11 @@ static int sync_io(struct dm_io_client *
}
set_current_state(TASK_RUNNING);
+ if (io.eopnotsupp_bits && (rw & (1 << BIO_RW_BARRIER))) {
+ rw &= ~(1 << BIO_RW_BARRIER);
+ goto retry;
+ }
+
if (error_bits)
*error_bits = io.error_bits;
--
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