- offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
-
- /*
- * Map the range first and check that it is a delalloc extent
- * before trying to unmap the range. Otherwise we will be
- * trying to remove a real extent (which requires a
- * transaction) or a hole, which is probably a bad idea...
- */
- error = xfs_bmapi(NULL, ip, offset_fsb, 1,
- XFS_BMAPI_ENTIRE, NULL, 0, &imap,
- &nimaps, NULL);
-
- if (error) {
- /* something screwed, just bail */
- if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
- xfs_fs_cmn_err(CE_ALERT, ip->i_mount,
- "page discard failed delalloc mapping lookup.");
- }
- break;
- }
- if (!nimaps) {
- /* nothing there */
- goto next_buffer;
- }
- if (imap.br_startblock != DELAYSTARTBLOCK) {
- /* been converted, ignore */
- goto next_buffer;
- }
- WARN_ON(imap.br_blockcount == 0);
-
- /*
- * Note: while we initialise the firstblock/flist pair, they
- * should never be used because blocks should never be
- * allocated or freed for a delalloc extent and hence we need
- * don't cancel or finish them after the xfs_bunmapi() call.
- */
- xfs_bmap_init(&flist, &firstblock);
- error = xfs_bunmapi(NULL, ip, offset_fsb, 1, 0, 1, &firstblock,
- &flist, &done);
-
- ASSERT(!flist.xbf_count && !flist.xbf_first);