2 files changed, 49 insertions, 37 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fde8acfac320..ef3ad99562c1 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -328,6 +328,40 @@ static void free_disk_sb(mdk_rdev_t * rdev)
 }
 
 
+static int super_written(struct bio *bio, unsigned int bytes_done, int error)
+{
+        mdk_rdev_t *rdev = bio->bi_private;
+        if (bio->bi_size)
+                return 1;
+
+        if (error || !test_bit(BIO_UPTODATE, &bio->bi_flags))
+                md_error(rdev->mddev, rdev);
+
+        if (atomic_dec_and_test(&rdev->mddev->pending_writes))
+                wake_up(&rdev->mddev->sb_wait);
+        return 0;
+}
+
+void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
+                   sector_t sector, int size, struct page *page)
+{
+        /* write first size bytes of page to sector of rdev
+         * Increment mddev->pending_writes before returning
+         * and decrement it on completion, waking up sb_wait
+         * if zero is reached.
+         * If an error occurred, call md_error
+         */
+        struct bio *bio = bio_alloc(GFP_NOIO, 1);
+
+        bio->bi_bdev = rdev->bdev;
+        bio->bi_sector = sector;
+        bio_add_page(bio, page, size, 0);
+        bio->bi_private = rdev;
+        bio->bi_end_io = super_written;
+        atomic_inc(&mddev->pending_writes);
+        submit_bio((1<<BIO_RW)|(1<<BIO_RW_SYNC), bio);
+}
+
 static int bi_complete(struct bio *bio, unsigned int bytes_done, int error)
 {
         if (bio->bi_size)
@@ -1268,30 +1302,6 @@ void md_print_devices(void)
 }
 
 
-static int write_disk_sb(mdk_rdev_t * rdev)
-{
-        char b[BDEVNAME_SIZE];
-        if (!rdev->sb_loaded) {
-                MD_BUG();
-                return 1;
-        }
-        if (rdev->faulty) {
-                MD_BUG();
-                return 1;
-        }
-
-        dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
-                bdevname(rdev->bdev,b),
-               (unsigned long long)rdev->sb_offset);
-  
-        if (sync_page_io(rdev->bdev, rdev->sb_offset<<1, MD_SB_BYTES, rdev->sb_page, WRITE))
-                return 0;
-
-        printk("md: write_disk_sb failed for device %s\n", 
-                bdevname(rdev->bdev,b));
-        return 1;
-}
-
 static void sync_sbs(mddev_t * mddev)
 {
         mdk_rdev_t *rdev;
@@ -1306,7 +1316,7 @@ static void sync_sbs(mddev_t * mddev)
 
 static void md_update_sb(mddev_t * mddev)
 {
-        int err, count = 100;
+        int err;
         struct list_head *tmp;
         mdk_rdev_t *rdev;
         int sync_req;
@@ -1326,6 +1336,7 @@ repeat:
                 MD_BUG();
                 mddev->events --;
         }
+        mddev->sb_dirty = 2;
         sync_sbs(mddev);
 
         /*
@@ -1353,24 +1364,24 @@ repeat:
 
                 dprintk("%s ", bdevname(rdev->bdev,b));
                 if (!rdev->faulty) {
-                        err += write_disk_sb(rdev);
+                        md_super_write(mddev,rdev,
+                                       rdev->sb_offset<<1, MD_SB_BYTES,
+                                       rdev->sb_page);
+                        dprintk(KERN_INFO "(write) %s's sb offset: %llu\n",
+                                bdevname(rdev->bdev,b),
+                                (unsigned long long)rdev->sb_offset);
+
                 } else
                         dprintk(")\n");
-                if (!err && mddev->level == LEVEL_MULTIPATH)
+                if (mddev->level == LEVEL_MULTIPATH)
                         /* only need to write one superblock... */
                         break;
         }
-        if (err) {
-                if (--count) {
-                        printk(KERN_ERR "md: errors occurred during superblock"
-                                " update, repeating\n");
-                        goto repeat;
-                }
-                printk(KERN_ERR \
-                        "md: excessive errors occurred during superblock update, exiting\n");
-        }
+        wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
+        /* if there was a failure, sb_dirty was set to 1, and we re-write super */
+
         spin_lock(&mddev->write_lock);
-        if (mddev->in_sync != sync_req) {
+        if (mddev->in_sync != sync_req|| mddev->sb_dirty == 1) {
                 /* have to write it out again */
                 spin_unlock(&mddev->write_lock);
                 goto repeat;
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index a3725b57fb7d..8c14ba565a45 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -262,6 +262,7 @@ struct mddev_s
 
         spinlock_t                      write_lock;
         wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
+        atomic_t                        pending_writes; /* number of active superblock writes */
 
         unsigned int                    safemode;       /* if set, update "clean" superblock
                                                          * when no writes pending.