3 files changed, 26 insertions, 6 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index c88f1e16ce2..bb4a8d2200d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -544,6 +544,7 @@ struct btrfs_fs_info {
         struct list_head hashers;
         struct list_head dead_roots;
         atomic_t nr_async_submits;
+        atomic_t nr_async_bios;
 
         /*
          * this is used by the balancing code to wait for all the pending
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 99bd9f9b9ee..9902d29abd0 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -429,6 +429,21 @@ int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
         return 0;
 }
 
+static int congested_async(struct btrfs_fs_info *info, int iodone)
+{
+        int limit = 256 * info->fs_devices->open_devices;
+
+        if (iodone)
+                limit = (limit * 3) / 2;
+        if (atomic_read(&info->nr_async_submits) > limit)
+                return 1;
+
+        limit = 8192 * info->fs_devices->open_devices;
+        if (iodone)
+                limit = (limit * 3) / 2;
+        return atomic_read(&info->nr_async_bios) > limit;
+}
+
 static void run_one_async_submit(struct btrfs_work *work)
 {
         struct btrfs_fs_info *fs_info;
@@ -437,6 +452,11 @@ static void run_one_async_submit(struct btrfs_work *work)
         async = container_of(work, struct  async_submit_bio, work);
         fs_info = BTRFS_I(async->inode)->root->fs_info;
         atomic_dec(&fs_info->nr_async_submits);
+
+        if ((async->bio->bi_rw & (1 << BIO_RW)) &&
+            !congested_async(fs_info, 1)) {
+                clear_bdi_congested(&fs_info->bdi, WRITE);
+        }
         async->submit_bio_hook(async->inode, async->rw, async->bio,
                                async->mirror_num);
         kfree(async);
@@ -938,15 +958,13 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
 {
         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
         int ret = 0;
-        int limit = 256 * info->fs_devices->open_devices;
         struct list_head *cur;
         struct btrfs_device *device;
         struct backing_dev_info *bdi;
 
         if ((bdi_bits & (1 << BDI_write_congested)) &&
-            atomic_read(&info->nr_async_submits) > limit) {
+            congested_async(info, 0))
                 return 1;
-        }
 
         list_for_each(cur, &info->fs_devices->devices) {
                 device = list_entry(cur, struct btrfs_device, dev_list);
@@ -1250,6 +1268,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         INIT_LIST_HEAD(&fs_info->space_info);
         btrfs_mapping_init(&fs_info->mapping_tree);
         atomic_set(&fs_info->nr_async_submits, 0);
+        atomic_set(&fs_info->nr_async_bios, 0);
         atomic_set(&fs_info->throttles, 0);
         atomic_set(&fs_info->throttle_gen, 0);
         fs_info->sb = sb;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 09311b3066d..23a5b0aba00 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -179,7 +179,7 @@ loop:
                 cur = pending;
                 pending = pending->bi_next;
                 cur->bi_next = NULL;
-                atomic_dec(&device->dev_root->fs_info->nr_async_submits);
+                atomic_dec(&device->dev_root->fs_info->nr_async_bios);
 
                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
                 bio_get(cur);
@@ -2145,12 +2145,12 @@ int schedule_bio(struct btrfs_root *root, struct btrfs_device *device,
         }
 
         /*
-         * nr_async_sumbits allows us to reliably return congestion to the
+         * nr_async_bios allows us to reliably return congestion to the
          * higher layers.  Otherwise, the async bio makes it appear we have
          * made progress against dirty pages when we've really just put it
          * on a queue for later
          */
-        atomic_inc(&root->fs_info->nr_async_submits);
+        atomic_inc(&root->fs_info->nr_async_bios);
         WARN_ON(bio->bi_next);
         bio->bi_next = NULL;
         bio->bi_rw |= rw;