Btrfs: Add some simple throttling to wait for data=ordered and snapshot deletion

Signed-off-by: Chris Mason <chris.mason@oracle.com>

6 files changed, 26 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b55dba58dfaa..f0fb1978553c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -345,6 +345,7 @@ struct btrfs_fs_info {
         struct completion kobj_unregister;
         int do_barriers;
         int closing;
+        unsigned long throttles;
 
         u64 total_pinned;
         spinlock_t delalloc_lock;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 34cf1f1f47be..e0940a39ff07 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -631,6 +631,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         fs_info->tree_root = tree_root;
         fs_info->extent_root = extent_root;
         fs_info->sb = sb;
+        fs_info->throttles = 0;
         fs_info->mount_opt = 0;
         fs_info->max_extent = (u64)-1;
         fs_info->delalloc_bytes = 0;
@@ -889,6 +890,12 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->extent_tree, buf);
 }
 
+void btrfs_throttle(struct btrfs_root *root)
+{
+        if (root->fs_info->throttles)
+                congestion_wait(WRITE, HZ/10);
+}
+
 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
 {
         balance_dirty_pages_ratelimited_nr(
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index dae9fba8efcd..828f3a2081b6 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -64,4 +64,5 @@ int btrfs_clear_buffer_defrag_done(struct extent_buffer *buf);
 int btrfs_read_buffer(struct extent_buffer *buf);
 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len);
 void btrfs_csum_final(u32 crc, char *result);
+void btrfs_throttle(struct btrfs_root *root);
 #endif
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 0a5f4defe59b..897242e87fa7 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -800,6 +800,7 @@ 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 10cece11dbd8..2cb2dd32407e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -610,6 +610,7 @@ static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
 fail:
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return ret;
 }
 
@@ -644,6 +645,7 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
 fail:
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
 
         if (ret && !err)
                 err = ret;
@@ -1010,6 +1012,7 @@ void btrfs_delete_inode(struct inode *inode)
         btrfs_end_transaction(trans, root);
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return;
 
 no_delete_lock:
@@ -1017,6 +1020,7 @@ no_delete_lock:
         btrfs_end_transaction(trans, root);
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
 no_delete:
         clear_inode(inode);
 }
@@ -1574,6 +1578,7 @@ fail:
                 iput(inode);
         }
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return err;
 }
 
@@ -1633,6 +1638,7 @@ fail:
                 iput(inode);
         }
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return err;
 }
 
@@ -1684,6 +1690,7 @@ fail:
                 iput(inode);
         }
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return err;
 }
 
@@ -1752,6 +1759,7 @@ out_unlock:
         if (drop_on_err)
                 iput(inode);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return err;
 }
 
@@ -2117,6 +2125,7 @@ static void btrfs_truncate(struct inode *inode)
         BUG_ON(ret);
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
 }
 
 static int noinline create_subvol(struct btrfs_root *root, char *name,
@@ -2245,6 +2254,7 @@ fail:
 fail_commit:
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return ret;
 }
 
@@ -2287,6 +2297,7 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 fail_unlock:
         mutex_unlock(&root->fs_info->fs_mutex);
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return ret;
 }
 
@@ -2827,6 +2838,7 @@ out_fail:
                 iput(inode);
         }
         btrfs_btree_balance_dirty(root, nr);
+        btrfs_throttle(root);
         return err;
 }
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index dc9865323e38..614903f5c884 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -424,6 +424,7 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
 
                 num_bytes = btrfs_root_used(&dirty->root->root_item);
                 root = dirty->latest_root;
+                root->fs_info->throttles++;
 
                 while(1) {
                         trans = btrfs_start_transaction(tree_root, 1);
@@ -447,6 +448,7 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
                         mutex_lock(&tree_root->fs_info->fs_mutex);
                 }
                 BUG_ON(ret);
+                root->fs_info->throttles--;
 
                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
                 bytes_used = btrfs_root_used(&root->root_item);
@@ -484,6 +486,7 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
         u64 objectid = 0;
         int ret;
 
+        root->fs_info->throttles++;
         while(1) {
                 ret = btrfs_find_first_ordered_inode(
                                 &cur_trans->ordered_inode_tree,
@@ -523,6 +526,7 @@ int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
                 mutex_lock(&root->fs_info->fs_mutex);
                 mutex_lock(&root->fs_info->trans_mutex);
         }
+        root->fs_info->throttles--;
         return 0;
 }