[dm-devel] [PATCH 4/8] raid1 barriers
Mikulas Patocka
mpatocka at redhat.com
Mon Apr 27 11:49:50 UTC 2009
Introduce flush_header and use it to flush the log device.
Note that we don't have to flush if all the regions transition
from "dirty" to "clean" state.
Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
---
drivers/md/dm-log.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
Index: linux-2.6.30-rc2-devel/drivers/md/dm-log.c
===================================================================
--- linux-2.6.30-rc2-devel.orig/drivers/md/dm-log.c 2009-04-24 11:06:19.000000000 +0200
+++ linux-2.6.30-rc2-devel/drivers/md/dm-log.c 2009-04-24 11:07:46.000000000 +0200
@@ -288,6 +288,18 @@ static int rw_header(struct log_c *lc, i
return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
}
+static int flush_header(struct log_c *lc)
+{
+ struct dm_io_region null_location = {
+ .bdev = lc->header_location.bdev,
+ .sector = 0,
+ .count = 0,
+ };
+ lc->io_req.bi_rw = WRITE_BARRIER;
+
+ return dm_io(&lc->io_req, 1, &null_location, NULL);
+}
+
static int read_header(struct log_c *log)
{
int r;
@@ -614,6 +626,8 @@ static int disk_resume(struct dm_dirty_l
/* write the new header */
r = rw_header(lc, WRITE);
+ if (!r)
+ r = flush_header(lc);
if (r) {
DMWARN("%s: Failed to write header on dirty region log device",
lc->log_dev->name);
@@ -667,7 +681,13 @@ static int disk_flush(struct dm_dirty_lo
if (r)
fail_log_device(lc);
else {
- lc->touched_dirtied = 0;
+ if (lc->touched_dirtied) {
+ r = flush_header(lc);
+ if (r)
+ fail_log_device(lc);
+ else
+ lc->touched_dirtied = 0;
+ }
lc->touched_cleaned = 0;
}
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