Subject: Rework btrfs_file_write to only allocate while page locks are held

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

fs/btrfs/disk-io.c

@@ -541,6 +541,8 @@ int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 	else
 		ret = submit_bh(WRITE, bh);
 	if (ret == -EOPNOTSUPP) {
+		get_bh(bh);
+		lock_buffer(bh);
 		set_buffer_uptodate(bh);
 		root->fs_info->do_barriers = 0;
 		ret = submit_bh(WRITE, bh);

fs/btrfs/extent-tree.c

@@ -1477,7 +1477,6 @@ int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
 			break;
 		if (wret < 0)
 			ret = wret;
-		btrfs_btree_balance_dirty(root);
 	}
 	for (i = 0; i <= orig_level; i++) {
 		if (path->nodes[i]) {

fs/btrfs/file-item.c

@@ -228,7 +228,6 @@ int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
 			   path->nodes[0]->b_data,
 			   root->fs_info->sb->s_blocksize);
 	ret = btrfs_csum_data(root, data, len, &item->csum);
-// printk("file %lu offset %llu csum %X\n", objectid, (unsigned long long)offset, *(int *)(&item->csum));
 	btrfs_mark_buffer_dirty(path->nodes[0]);
 fail:
 	btrfs_release_path(root, path);

fs/btrfs/inode.c

@@ -962,7 +962,6 @@ void btrfs_dirty_inode(struct inode *inode)
 	btrfs_update_inode(trans, root, inode);
 	btrfs_end_transaction(trans, root);
 	mutex_unlock(&root->fs_info->fs_mutex);
-	btrfs_btree_balance_dirty(root);
 }
 
 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
@@ -1402,7 +1401,6 @@ int btrfs_get_block_csum(struct inode *inode, sector_t iblock,
 		goto out;
 	}
 	memcpy((char *)&result->b_private, &item->csum, BTRFS_CRC32_SIZE);
-printk("get_block_sum file %lu offset %llu csum %X\n", inode->i_ino, (unsigned long long)offset, *(int *)(&item->csum));
 out:
 	if (path)
 		btrfs_free_path(path);
@@ -1476,7 +1474,6 @@ static void btrfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
 				       (unsigned long long)offset);
 				memset(kaddr + bh_offset(bh), 1, bh->b_size);
 				flush_dcache_page(page);
-printk("bad verify file %lu offset %llu bh_private %lX csum %X\n", inode->i_ino, (unsigned long long)offset, (unsigned long)(bh->b_private), *(int *)csum);
 			}
 			kunmap_atomic(kaddr, KM_IRQ0);
 		}
@@ -1655,6 +1652,13 @@ static int __btrfs_write_full_page(struct inode *inode, struct page *page,
 
 	last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
 
+	/* no csumming allowed when from PF_MEMALLOC */
+	if (current->flags & PF_MEMALLOC) {
+		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
+		return 0;
+	}
+
 	if (!page_has_buffers(page)) {
 		create_empty_buffers(page, blocksize,
 					(1 << BH_Dirty)|(1 << BH_Uptodate));
@@ -1885,7 +1889,6 @@ int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 
 	lock_page(page);
 	wait_on_page_writeback(page);
-printk("btrfs_page_mkwrite %lu %lu\n", page->mapping->host->i_ino, page->index);
 	size = i_size_read(inode);
 	if ((page->mapping != inode->i_mapping) ||
 	    ((page->index << PAGE_CACHE_SHIFT) > size)) {

fs/btrfs/print-tree.c

@@ -31,6 +31,7 @@ void btrfs_print_leaf(struct btrfs_root *root, struct btrfs_leaf *l)
 	struct btrfs_dir_item *di;
 	struct btrfs_inode_item *ii;
 	struct btrfs_block_group_item *bi;
+	struct btrfs_file_extent_item *fi;
 	u32 type;
 
 	printk("leaf %llu total ptrs %d free space %d\n",
@@ -75,6 +76,23 @@ void btrfs_print_leaf(struct btrfs_root *root, struct btrfs_leaf *l)
 			printk("\t\textent data refs %u\n",
 				btrfs_extent_refs(ei));
 			break;
+
+		case BTRFS_EXTENT_DATA_KEY:
+			fi = btrfs_item_ptr(l, i,
+					    struct btrfs_file_extent_item);
+			if (btrfs_file_extent_type(fi) ==
+			    BTRFS_FILE_EXTENT_INLINE) {
+				printk("\t\tinline extent data size %u\n",
+			           btrfs_file_extent_inline_len(l->items + i));
+				break;
+			}
+			printk("\t\textent data disk block %llu nr %llu\n",
+			       (unsigned long long)btrfs_file_extent_disk_blocknr(fi),
+			       (unsigned long long)btrfs_file_extent_disk_num_blocks(fi));
+			printk("\t\textent data offset %llu nr %llu\n",
+			  (unsigned long long)btrfs_file_extent_offset(fi),
+			  (unsigned long long)btrfs_file_extent_num_blocks(fi));
+			break;
 		case BTRFS_BLOCK_GROUP_ITEM_KEY:
 			bi = btrfs_item_ptr(l, i,
 					    struct btrfs_block_group_item);

fs/btrfs/transaction.c

@@ -279,6 +279,7 @@ static int drop_dirty_roots(struct btrfs_root *tree_root,
 		BUG_ON(ret);
 		kfree(dirty);
 		mutex_unlock(&tree_root->fs_info->fs_mutex);
+		btrfs_btree_balance_dirty(tree_root);
 	}
 	return 0;
 }