Merge branch 'foreign/josef/space-updates' into for-chris-4.6

fs/btrfs/extent-tree.c

@@ -4838,7 +4838,7 @@ static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
 	u64 thresh = div_factor_fine(space_info->total_bytes, 98);
 
 	/* If we're just plain full then async reclaim just slows us down. */
-	if (space_info->bytes_used >= thresh)
+	if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
 		return 0;
 
 	return (used >= thresh && !btrfs_fs_closing(fs_info) &&
@@ -5373,27 +5373,33 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
 
 	block_rsv->size = min_t(u64, num_bytes, SZ_512M);
 
+	if (block_rsv->reserved < block_rsv->size) {
 		num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
 			sinfo->bytes_reserved + sinfo->bytes_readonly +
 			sinfo->bytes_may_use;
-
 		if (sinfo->total_bytes > num_bytes) {
 			num_bytes = sinfo->total_bytes - num_bytes;
+			num_bytes = min(num_bytes,
+					block_rsv->size - block_rsv->reserved);
 			block_rsv->reserved += num_bytes;
 			sinfo->bytes_may_use += num_bytes;
 			trace_btrfs_space_reservation(fs_info, "space_info",
-				      sinfo->flags, num_bytes, 1);
+						      sinfo->flags, num_bytes,
+						      1);
 		}
-
-	if (block_rsv->reserved >= block_rsv->size) {
+	} else if (block_rsv->reserved > block_rsv->size) {
 		num_bytes = block_rsv->reserved - block_rsv->size;
 		sinfo->bytes_may_use -= num_bytes;
 		trace_btrfs_space_reservation(fs_info, "space_info",
 				      sinfo->flags, num_bytes, 0);
 		block_rsv->reserved = block_rsv->size;
-		block_rsv->full = 1;
 	}
 
+	if (block_rsv->reserved == block_rsv->size)
+		block_rsv->full = 1;
+	else
+		block_rsv->full = 0;
+
 	spin_unlock(&block_rsv->lock);
 	spin_unlock(&sinfo->lock);
 }

fs/btrfs/inode.c

@@ -4212,11 +4212,20 @@ static int truncate_space_check(struct btrfs_trans_handle *trans,
 {
 	int ret;
 
+	/*
+	 * This is only used to apply pressure to the enospc system, we don't
+	 * intend to use this reservation at all.
+	 */
 	bytes_deleted = btrfs_csum_bytes_to_leaves(root, bytes_deleted);
+	bytes_deleted *= root->nodesize;
 	ret = btrfs_block_rsv_add(root, &root->fs_info->trans_block_rsv,
 				  bytes_deleted, BTRFS_RESERVE_NO_FLUSH);
-	if (!ret)
+	if (!ret) {
+		trace_btrfs_space_reservation(root->fs_info, "transaction",
+					      trans->transid,
+					      bytes_deleted, 1);
 		trans->bytes_reserved += bytes_deleted;
+	}
 	return ret;
 
 }

fs/btrfs/transaction.c

@@ -637,6 +637,8 @@ struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
 
 	trans->block_rsv = &root->fs_info->trans_block_rsv;
 	trans->bytes_reserved = num_bytes;
+	trace_btrfs_space_reservation(root->fs_info, "transaction",
+				      trans->transid, num_bytes, 1);
 
 	return trans;
 }
@@ -1375,7 +1377,9 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
 	rsv = trans->block_rsv;
 	trans->block_rsv = &pending->block_rsv;
 	trans->bytes_reserved = trans->block_rsv->reserved;
-
+	trace_btrfs_space_reservation(root->fs_info, "transaction",
+				      trans->transid,
+				      trans->bytes_reserved, 1);
 	dentry = pending->dentry;
 	parent_inode = pending->dir;
 	parent_root = BTRFS_I(parent_inode)->root;