md: add honouring of suspend_{lo,hi} to raid1.

This will allow us to stop writeout to portions of the array
while  they are resynced by someone else - e.g. another node in
a cluster.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index e07ce2e033a9..35b2d8646ae9 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -801,6 +801,25 @@ static int make_request(struct request_queue *q, struct bio * bio)
 
         md_write_start(mddev, bio); /* wait on superblock update early */
 
+        if (bio_data_dir(bio) == WRITE &&
+            bio->bi_sector + bio->bi_size/512 > mddev->suspend_lo &&
+            bio->bi_sector < mddev->suspend_hi) {
+                /* As the suspend_* range is controlled by
+                 * userspace, we want an interruptible
+                 * wait.
+                 */
+                DEFINE_WAIT(w);
+                for (;;) {
+                        flush_signals(current);
+                        prepare_to_wait(&conf->wait_barrier,
+                                        &w, TASK_INTERRUPTIBLE);
+                        if (bio->bi_sector + bio->bi_size/512 <= mddev->suspend_lo ||
+                            bio->bi_sector >= mddev->suspend_hi)
+                                break;
+                        schedule();
+                }
+                finish_wait(&conf->wait_barrier, &w);
+        }
         if (unlikely(!mddev->barriers_work &&
                      bio_rw_flagged(bio, BIO_RW_BARRIER))) {
                 if (rw == WRITE)
@@ -2271,6 +2290,9 @@ static void raid1_quiesce(mddev_t *mddev, int state)
         conf_t *conf = mddev->private;
 
         switch(state) {
+        case 2: /* wake for suspend */
+                wake_up(&conf->wait_barrier);
+                break;
         case 1:
                 raise_barrier(conf);
                 break;