- while (1) {
- lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
- 0, &cached_state);
- /*
- * We're concerned with the entire range that we're going to be
- * doing DIO to, so we need to make sure theres no ordered
- * extents in this range.
- */
- ordered = btrfs_lookup_ordered_range(inode, lockstart,
- lockend - lockstart + 1);
-
- /*
- * We need to make sure there are no buffered pages in this
- * range either, we could have raced between the invalidate in
- * generic_file_direct_write and locking the extent. The
- * invalidate needs to happen so that reads after a write do not
- * get stale data.
- */
- if (!ordered && (!writing ||
- !test_range_bit(&BTRFS_I(inode)->io_tree,
- lockstart, lockend, EXTENT_UPTODATE, 0,
- cached_state)))
- break;
-
- unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
- &cached_state, GFP_NOFS);
-
- if (ordered) {
- btrfs_start_ordered_extent(inode, ordered, 1);
- btrfs_put_ordered_extent(ordered);
- } else {
- /* Screw you mmap */
- ret = filemap_write_and_wait_range(file->f_mapping,
- lockstart,
- lockend);
- if (ret)
- goto out;
-
- /*
- * If we found a page that couldn't be invalidated just
- * fall back to buffered.
- */
- ret = invalidate_inode_pages2_range(file->f_mapping,
- lockstart >> PAGE_CACHE_SHIFT,
- lockend >> PAGE_CACHE_SHIFT);
- if (ret) {
- if (ret == -EBUSY)
- ret = 0;
- goto out;
- }
- }
-
- cond_resched();
- }
-
- /*
- * we don't use btrfs_set_extent_delalloc because we don't want
- * the dirty or uptodate bits
- */
- if (writing) {
- write_bits = EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING;
- ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
- EXTENT_DELALLOC, NULL, &cached_state,
- GFP_NOFS);
- if (ret) {
- clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
- lockend, EXTENT_LOCKED | write_bits,
- 1, 0, &cached_state, GFP_NOFS);
- goto out;
- }
- }
-
- free_extent_state(cached_state);
- cached_state = NULL;
-
- ret = __blockdev_direct_IO(rw, iocb, inode,