dm raid1: implement mirror_flush

Implement flush callee. It uses dm_io to send zero-size barrier synchronously
and concurrently to all the mirror legs.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 36 insertions, 1 deletions

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index d44bc497dad9..751660b0c574 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -237,6 +237,40 @@ out:
         schedule_work(&ms->trigger_event);
 }
 
+static int mirror_flush(struct dm_target *ti)
+{
+        struct mirror_set *ms = ti->private;
+        unsigned long error_bits;
+
+        unsigned int i;
+        struct dm_io_region io[ms->nr_mirrors];
+        struct mirror *m;
+        struct dm_io_request io_req = {
+                .bi_rw = WRITE_BARRIER,
+                .mem.type = DM_IO_KMEM,
+                .mem.ptr.bvec = NULL,
+                .client = ms->io_client,
+        };
+
+        for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
+                io[i].bdev = m->dev->bdev;
+                io[i].sector = 0;
+                io[i].count = 0;
+        }
+
+        error_bits = -1;
+        dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
+        if (unlikely(error_bits != 0)) {
+                for (i = 0; i < ms->nr_mirrors; i++)
+                        if (test_bit(i, &error_bits))
+                                fail_mirror(ms->mirror + i,
+                                            DM_RAID1_WRITE_ERROR);
+                return -EIO;
+        }
+
+        return 0;
+}
+
 /*-----------------------------------------------------------------
  * Recovery.
  *
@@ -896,7 +930,8 @@ static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
                 return NULL;
         }
 
-        dl = dm_dirty_log_create(argv[0], ti, NULL, param_count, argv + 2);
+        dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
+                                 argv + 2);
         if (!dl) {
                 ti->error = "Error creating mirror dirty log";
                 return NULL;