Merge tag 'md/4.4-rc5-fixes' of git://neil.brown.name/md

Pull md fixes from Neil Brown:
 "Four fixes for md:

   - two recently introduced regressions fixed.
   - one older bug in RAID10 - tagged for -stable since 4.2
   - one minor sysfs api improvement"

* tag 'md/4.4-rc5-fixes' of git://neil.brown.name/md:
  Fix remove_and_add_spares removes drive added as spare in slot_store
  md: fix bug due to nested suspend
  MD: change journal disk role to disk 0
  md/raid10: fix data corruption and crash during resync

3 files changed, 24 insertions, 10 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 807095f4c793..dbedc58d8c00 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -314,8 +314,8 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
  */
 void mddev_suspend(struct mddev *mddev)
 {
-        BUG_ON(mddev->suspended);
-        mddev->suspended = 1;
+        if (mddev->suspended++)
+                return;
         synchronize_rcu();
         wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
         mddev->pers->quiesce(mddev, 1);
@@ -326,7 +326,8 @@ EXPORT_SYMBOL_GPL(mddev_suspend);
 
 void mddev_resume(struct mddev *mddev)
 {
-        mddev->suspended = 0;
+        if (--mddev->suspended)
+                return;
         wake_up(&mddev->sb_wait);
         mddev->pers->quiesce(mddev, 0);
 
@@ -1652,7 +1653,7 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
                         rdev->journal_tail = le64_to_cpu(sb->journal_tail);
                         if (mddev->recovery_cp == MaxSector)
                                 set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
-                        rdev->raid_disk = mddev->raid_disks;
+                        rdev->raid_disk = 0;
                         break;
                 default:
                         rdev->saved_raid_disk = role;
@@ -2773,6 +2774,7 @@ slot_store(struct md_rdev *rdev, const char *buf, size_t len)
                 /* Activating a spare .. or possibly reactivating
                  * if we ever get bitmaps working here.
                  */
+                int err;
 
                 if (rdev->raid_disk != -1)
                         return -EBUSY;
@@ -2794,9 +2796,15 @@ slot_store(struct md_rdev *rdev, const char *buf, size_t len)
                         rdev->saved_raid_disk = -1;
                 clear_bit(In_sync, &rdev->flags);
                 clear_bit(Bitmap_sync, &rdev->flags);
-                remove_and_add_spares(rdev->mddev, rdev);
-                if (rdev->raid_disk == -1)
-                        return -EBUSY;
+                err = rdev->mddev->pers->
+                        hot_add_disk(rdev->mddev, rdev);
+                if (err) {
+                        rdev->raid_disk = -1;
+                        return err;
+                } else
+                        sysfs_notify_dirent_safe(rdev->sysfs_state);
+                if (sysfs_link_rdev(rdev->mddev, rdev))
+                        /* failure here is OK */;
                 /* don't wakeup anyone, leave that to userspace. */
         } else {
                 if (slot >= rdev->mddev->raid_disks &&
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 2bea51edfab7..ca0b643fe3c1 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -566,7 +566,9 @@ static inline char * mdname (struct mddev * mddev)
 static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 {
         char nm[20];
-        if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
+        if (!test_bit(Replacement, &rdev->flags) &&
+            !test_bit(Journal, &rdev->flags) &&
+            mddev->kobj.sd) {
                 sprintf(nm, "rd%d", rdev->raid_disk);
                 return sysfs_create_link(&mddev->kobj, &rdev->kobj, nm);
         } else
@@ -576,7 +578,9 @@ static inline int sysfs_link_rdev(struct mddev *mddev, struct md_rdev *rdev)
 static inline void sysfs_unlink_rdev(struct mddev *mddev, struct md_rdev *rdev)
 {
         char nm[20];
-        if (!test_bit(Replacement, &rdev->flags) && mddev->kobj.sd) {
+        if (!test_bit(Replacement, &rdev->flags) &&
+            !test_bit(Journal, &rdev->flags) &&
+            mddev->kobj.sd) {
                 sprintf(nm, "rd%d", rdev->raid_disk);
                 sysfs_remove_link(&mddev->kobj, nm);
         }
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 41d70bc9ba2f..84e597e1c489 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1946,6 +1946,8 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
 
         first = i;
         fbio = r10_bio->devs[i].bio;
+        fbio->bi_iter.bi_size = r10_bio->sectors << 9;
+        fbio->bi_iter.bi_idx = 0;
 
         vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
         /* now find blocks with errors */
@@ -1989,7 +1991,7 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
                 bio_reset(tbio);
 
                 tbio->bi_vcnt = vcnt;
-                tbio->bi_iter.bi_size = r10_bio->sectors << 9;
+                tbio->bi_iter.bi_size = fbio->bi_iter.bi_size;
                 tbio->bi_rw = WRITE;
                 tbio->bi_private = r10_bio;
                 tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;