1253 	 * At this point trimming or scrub can't start on this block group,  in btrfs_remove_block_group()
1258 	 * if they didn't, for the trimming case they won't find any free space  in btrfs_remove_block_group()
1265 	 * avoid races with trimming and scrub.  in btrfs_remove_block_group()
1268 	 * completely transactionless, so while it is trimming a range the  in btrfs_remove_block_group()
1488 		int trimming;  in btrfs_delete_unused_bgs()  local
1654 		 * then trimming is handled in the transaction commit path.  in btrfs_delete_unused_bgs()
1655 		 * Async discard interposes before this to do the trimming  in btrfs_delete_unused_bgs()
1656 		 * before coming down the unused block group path as trimming  in btrfs_delete_unused_bgs()
1666 		trimming = btrfs_test_opt(fs_info, DISCARD_SYNC) ||  in btrfs_delete_unused_bgs()
1670 		if (trimming)  in btrfs_delete_unused_bgs()
1680 			if (trimming)  in btrfs_delete_unused_bgs()
1690 		if (trimming) {  in btrfs_delete_unused_bgs()
4556 		 * tasks trimming this block group have left 1 entry each one.  in btrfs_unfreeze_block_group()