7 files changed, 58 insertions, 22 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4eca0aa1ce74..5517dfc6f71c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -580,6 +580,7 @@ struct btrfs_fs_info {
         int do_barriers;
         int closing;
         atomic_t throttles;
+        atomic_t throttle_gen;
 
         u64 total_pinned;
         struct list_head dirty_cowonly_roots;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index eccdf13a95ac..27ffa9b7ddc8 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1171,8 +1171,10 @@ static int transaction_kthread(void *arg)
                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
 
-                printk("btrfs: total reference cache size %Lu\n",
-                        root->fs_info->total_ref_cache_size);
+                if (root->fs_info->total_ref_cache_size > 20 * 1024 * 1024) {
+                        printk("btrfs: total reference cache size %Lu\n",
+                                root->fs_info->total_ref_cache_size);
+                }
 
                 mutex_lock(&root->fs_info->trans_mutex);
                 cur = root->fs_info->running_transaction;
@@ -1256,6 +1258,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         btrfs_mapping_init(&fs_info->mapping_tree);
         atomic_set(&fs_info->nr_async_submits, 0);
         atomic_set(&fs_info->throttles, 0);
+        atomic_set(&fs_info->throttle_gen, 0);
         fs_info->sb = sb;
         fs_info->max_extent = (u64)-1;
         fs_info->max_inline = 8192 * 1024;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 0e294cfaa60c..6290cf41d647 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2650,6 +2650,7 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
                 }
         }
         while(1) {
+                atomic_inc(&root->fs_info->throttle_gen);
                 wret = walk_down_tree(trans, root, path, &level);
                 if (wret > 0)
                         break;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 3efec25e34b0..ded5281f8463 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -974,6 +974,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
                 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
                         btrfs_btree_balance_dirty(root, 1);
+                btrfs_throttle(root);
                 cond_resched();
         }
 out:
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4f977ea5497e..7c87f863d6f7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2482,7 +2482,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         btrfs_update_inode_block_group(trans, dir);
 out_unlock:
         nr = trans->blocks_used;
-        btrfs_end_transaction(trans, root);
+        btrfs_end_transaction_throttle(trans, root);
 fail:
         if (drop_inode) {
                 inode_dec_link_count(inode);
@@ -2535,7 +2535,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
                 drop_inode = 1;
 
         nr = trans->blocks_used;
-        btrfs_end_transaction(trans, root);
+        btrfs_end_transaction_throttle(trans, root);
 fail:
         if (drop_inode) {
                 inode_dec_link_count(inode);
@@ -2609,7 +2609,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
 out_fail:
         nr = trans->blocks_used;
-        btrfs_end_transaction(trans, root);
+        btrfs_end_transaction_throttle(trans, root);
 
 out_unlock:
         if (drop_on_err)
@@ -3434,7 +3434,7 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
                 goto out_fail;
 
 out_fail:
-        btrfs_end_transaction(trans, root);
+        btrfs_end_transaction_throttle(trans, root);
 out_unlock:
         return ret;
 }
@@ -3548,7 +3548,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 
 out_unlock:
         nr = trans->blocks_used;
-        btrfs_end_transaction(trans, root);
+        btrfs_end_transaction_throttle(trans, root);
 out_fail:
         if (drop_inode) {
                 inode_dec_link_count(inode);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index fcef3cae0c92..b8be6703189a 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -202,35 +202,64 @@ static noinline int wait_for_commit(struct btrfs_root *root,
         return 0;
 }
 
+void btrfs_throttle(struct btrfs_root *root)
+{
+        struct btrfs_fs_info *info = root->fs_info;
+
+harder:
+        if (atomic_read(&info->throttles)) {
+                DEFINE_WAIT(wait);
+                int thr;
+                int harder_count = 0;
+                thr = atomic_read(&info->throttle_gen);
+
+                do {
+                        prepare_to_wait(&info->transaction_throttle,
+                                        &wait, TASK_UNINTERRUPTIBLE);
+                        if (!atomic_read(&info->throttles)) {
+                                finish_wait(&info->transaction_throttle, &wait);
+                                break;
+                        }
+                        schedule();
+                        finish_wait(&info->transaction_throttle, &wait);
+                } while (thr == atomic_read(&info->throttle_gen));
+
+                if (harder_count < 5 &&
+                    info->total_ref_cache_size > 5 * 1024 * 1024) {
+                        harder_count++;
+                        goto harder;
+                }
+
+                if (harder_count < 10 &&
+                    info->total_ref_cache_size > 10 * 1024 * 1024) {
+                        harder_count++;
+                        goto harder;
+                }
+        }
+}
+
 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
                           struct btrfs_root *root, int throttle)
 {
         struct btrfs_transaction *cur_trans;
+        struct btrfs_fs_info *info = root->fs_info;
 
-        mutex_lock(&root->fs_info->trans_mutex);
-        cur_trans = root->fs_info->running_transaction;
+        mutex_lock(&info->trans_mutex);
+        cur_trans = info->running_transaction;
         WARN_ON(cur_trans != trans->transaction);
         WARN_ON(cur_trans->num_writers < 1);
         cur_trans->num_writers--;
 
         if (waitqueue_active(&cur_trans->writer_wait))
                 wake_up(&cur_trans->writer_wait);
-
-        if (throttle && atomic_read(&root->fs_info->throttles)) {
-                DEFINE_WAIT(wait);
-                mutex_unlock(&root->fs_info->trans_mutex);
-                prepare_to_wait(&root->fs_info->transaction_throttle, &wait,
-                                TASK_UNINTERRUPTIBLE);
-                if (atomic_read(&root->fs_info->throttles))
-                        schedule();
-                finish_wait(&root->fs_info->transaction_throttle, &wait);
-                mutex_lock(&root->fs_info->trans_mutex);
-        }
-
         put_transaction(cur_trans);
-        mutex_unlock(&root->fs_info->trans_mutex);
+        mutex_unlock(&info->trans_mutex);
         memset(trans, 0, sizeof(*trans));
         kmem_cache_free(btrfs_trans_handle_cachep, trans);
+
+        if (throttle)
+                btrfs_throttle(root);
+
         return 0;
 }
 
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 11fbdeceb26c..df2ca2aad1c0 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -91,4 +91,5 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                              struct btrfs_root *root);
 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
                                    struct btrfs_root *root);
+void btrfs_throttle(struct btrfs_root *root);
 #endif