- convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
- mark, &cached_state, GFP_NOFS);
- cached_state = NULL;
- err = filemap_fdatawrite_range(mapping, start, end);
+ bool wait_writeback = false;
+
+ err = convert_extent_bit(dirty_pages, start, end,
+ EXTENT_NEED_WAIT,
+ mark, &cached_state, GFP_NOFS);
+ /*
+ * convert_extent_bit can return -ENOMEM, which is most of the
+ * time a temporary error. So when it happens, ignore the error
+ * and wait for writeback of this range to finish - because we
+ * failed to set the bit EXTENT_NEED_WAIT for the range, a call
+ * to btrfs_wait_marked_extents() would not know that writeback
+ * for this range started and therefore wouldn't wait for it to
+ * finish - we don't want to commit a superblock that points to
+ * btree nodes/leafs for which writeback hasn't finished yet
+ * (and without errors).
+ * We cleanup any entries left in the io tree when committing
+ * the transaction (through clear_btree_io_tree()).
+ */
+ if (err == -ENOMEM) {
+ err = 0;
+ wait_writeback = true;
+ }
+ if (!err)
+ err = filemap_fdatawrite_range(mapping, start, end);