1 files changed, 39 insertions, 77 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 51dcec86757f..e24b7964a155 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -216,17 +216,11 @@ static void wait_current_trans(struct btrfs_root *root)
 	spin_lock(&root->fs_info->trans_lock);
 	cur_trans = root->fs_info->running_transaction;
 	if (cur_trans && cur_trans->blocked) {
-		DEFINE_WAIT(wait);
 		atomic_inc(&cur_trans->use_count);
 		spin_unlock(&root->fs_info->trans_lock);
-		while (1) {
-			prepare_to_wait(&root->fs_info->transaction_wait, &wait,
-					TASK_UNINTERRUPTIBLE);
-			if (!cur_trans->blocked)
-				break;
-			schedule();
-		}
-		finish_wait(&root->fs_info->transaction_wait, &wait);
+
+		wait_event(root->fs_info->transaction_wait,
+			   !cur_trans->blocked);
 		put_transaction(cur_trans);
 	} else {
 		spin_unlock(&root->fs_info->trans_lock);
@@ -260,7 +254,7 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 {
 	struct btrfs_trans_handle *h;
 	struct btrfs_transaction *cur_trans;
-	int retries = 0;
+	u64 num_bytes = 0;
 	int ret;
 
 	if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
@@ -274,6 +268,19 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 		h->block_rsv = NULL;
 		goto got_it;
 	}
+
+	/*
+	 * Do the reservation before we join the transaction so we can do all
+	 * the appropriate flushing if need be.
+	 */
+	if (num_items > 0 && root != root->fs_info->chunk_root) {
+		num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
+		ret = btrfs_block_rsv_add(NULL, root,
+					  &root->fs_info->trans_block_rsv,
+					  num_bytes);
+		if (ret)
+			return ERR_PTR(ret);
+	}
 again:
 	h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 	if (!h)
@@ -310,24 +317,9 @@ again:
 		goto again;
 	}
 
-	if (num_items > 0) {
-		ret = btrfs_trans_reserve_metadata(h, root, num_items);
-		if (ret == -EAGAIN && !retries) {
-			retries++;
-			btrfs_commit_transaction(h, root);
-			goto again;
-		} else if (ret == -EAGAIN) {
-			/*
-			 * We have already retried and got EAGAIN, so really we
-			 * don't have space, so set ret to -ENOSPC.
-			 */
-			ret = -ENOSPC;
-		}
-
-		if (ret < 0) {
-			btrfs_end_transaction(h, root);
-			return ERR_PTR(ret);
-		}
+	if (num_bytes) {
+		h->block_rsv = &root->fs_info->trans_block_rsv;
+		h->bytes_reserved = num_bytes;
 	}
 
 got_it:
@@ -359,19 +351,10 @@ struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root
 }
 
 /* wait for a transaction commit to be fully complete */
-static noinline int wait_for_commit(struct btrfs_root *root,
+static noinline void wait_for_commit(struct btrfs_root *root,
 				    struct btrfs_transaction *commit)
 {
-	DEFINE_WAIT(wait);
-	while (!commit->commit_done) {
-		prepare_to_wait(&commit->commit_wait, &wait,
-				TASK_UNINTERRUPTIBLE);
-		if (commit->commit_done)
-			break;
-		schedule();
-	}
-	finish_wait(&commit->commit_wait, &wait);
-	return 0;
+	wait_event(commit->commit_wait, commit->commit_done);
 }
 
 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
@@ -499,10 +482,17 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
 	}
 
 	if (lock && cur_trans->blocked && !cur_trans->in_commit) {
-		if (throttle)
+		if (throttle) {
+			/*
+			 * We may race with somebody else here so end up having
+			 * to call end_transaction on ourselves again, so inc
+			 * our use_count.
+			 */
+			trans->use_count++;
 			return btrfs_commit_transaction(trans, root);
-		else
+		} else {
 			wake_up_process(info->transaction_kthread);
+		}
 	}
 
 	WARN_ON(cur_trans != info->running_transaction);
@@ -894,6 +884,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	struct btrfs_root *tree_root = fs_info->tree_root;
 	struct btrfs_root *root = pending->root;
 	struct btrfs_root *parent_root;
+	struct btrfs_block_rsv *rsv;
 	struct inode *parent_inode;
 	struct dentry *parent;
 	struct dentry *dentry;
@@ -905,6 +896,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	u64 objectid;
 	u64 root_flags;
 
+	rsv = trans->block_rsv;
+
 	new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
 	if (!new_root_item) {
 		pending->error = -ENOMEM;
@@ -1012,6 +1005,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	btrfs_orphan_post_snapshot(trans, pending);
 fail:
 	kfree(new_root_item);
+	trans->block_rsv = rsv;
 	btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
 	return 0;
 }
@@ -1080,22 +1074,7 @@ int btrfs_transaction_blocked(struct btrfs_fs_info *info)
 static void wait_current_trans_commit_start(struct btrfs_root *root,
 					    struct btrfs_transaction *trans)
 {
-	DEFINE_WAIT(wait);
-
-	if (trans->in_commit)
-		return;
-
-	while (1) {
-		prepare_to_wait(&root->fs_info->transaction_blocked_wait, &wait,
-				TASK_UNINTERRUPTIBLE);
-		if (trans->in_commit) {
-			finish_wait(&root->fs_info->transaction_blocked_wait,
-				    &wait);
-			break;
-		}
-		schedule();
-		finish_wait(&root->fs_info->transaction_blocked_wait, &wait);
-	}
+	wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
 }
 
 /*
@@ -1105,24 +1084,8 @@ static void wait_current_trans_commit_start(struct btrfs_root *root,
 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
 					 struct btrfs_transaction *trans)
 {
-	DEFINE_WAIT(wait);
-
-	if (trans->commit_done || (trans->in_commit && !trans->blocked))
-		return;
-
-	while (1) {
-		prepare_to_wait(&root->fs_info->transaction_wait, &wait,
-				TASK_UNINTERRUPTIBLE);
-		if (trans->commit_done ||
-		    (trans->in_commit && !trans->blocked)) {
-			finish_wait(&root->fs_info->transaction_wait,
-				    &wait);
-			break;
-		}
-		schedule();
-		finish_wait(&root->fs_info->transaction_wait,
-			    &wait);
-	}
+	wait_event(root->fs_info->transaction_wait,
+		   trans->commit_done || (trans->in_commit && !trans->blocked));
 }
 
 /*
@@ -1229,8 +1192,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 		atomic_inc(&cur_trans->use_count);
 		btrfs_end_transaction(trans, root);
 
-		ret = wait_for_commit(root, cur_trans);
-		BUG_ON(ret);
+		wait_for_commit(root, cur_trans);
 
 		put_transaction(cur_trans);