Commit 6aa0e7cc authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: implement hole punching for RAID stripe extents 



If the stripe extent we want to delete starts before the range we want to
delete and ends after the range we want to delete we're punching a
hole in the stripe extent:

  |--- RAID Stripe Extent ---|
  | keep |--- drop ---| keep |

This means we need to a) truncate the existing item and b)
create a second item for the remaining range.

Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 76643119

fs/btrfs/ctree.c

+1 −0
Original line number Diff line number Diff line
@@ -3833,6 +3833,7 @@ static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, 
	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);



	BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&

	       key.type != BTRFS_RAID_STRIPE_KEY &&

	       key.type != BTRFS_EXTENT_CSUM_KEY);



	if (btrfs_leaf_free_space(leaf) >= ins_len)

fs/btrfs/raid-stripe-tree.c

+48 −0
Original line number Diff line number Diff line
@@ -140,6 +140,54 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le 
		trace_btrfs_raid_extent_delete(fs_info, start, end,

					       found_start, found_end);



		/*

		 * The stripe extent starts before the range we want to delete

		 * and ends after the range we want to delete, i.e. we're

		 * punching a hole in the stripe extent:

		 *

		 *  |--- RAID Stripe Extent ---|

		 *  | keep |--- drop ---| keep |

		 *

		 * This means we need to a) truncate the existing item and b)

		 * create a second item for the remaining range.

		 */

		if (found_start < start && found_end > end) {

			size_t item_size;

			u64 diff_start = start - found_start;

			u64 diff_end = found_end - end;

			struct btrfs_stripe_extent *extent;

			struct btrfs_key newkey = {

				.objectid = end,

				.type = BTRFS_RAID_STRIPE_KEY,

				.offset = diff_end,

			};



			/* The "right" item. */

			ret = btrfs_duplicate_item(trans, stripe_root, path, &newkey);

			if (ret)

				break;



			item_size = btrfs_item_size(leaf, path->slots[0]);

			extent = btrfs_item_ptr(leaf, path->slots[0],

						struct btrfs_stripe_extent);



			for (int i = 0; i < btrfs_num_raid_stripes(item_size); i++) {

				struct btrfs_raid_stride *stride = &extent->strides[i];

				u64 phys;



				phys = btrfs_raid_stride_physical(leaf, stride);

				phys += diff_start + length;

				btrfs_set_raid_stride_physical(leaf, stride, phys);

			}



			/* The "left" item. */

			path->slots[0]--;

			btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);

			btrfs_partially_delete_raid_extent(trans, path, &key,

							   diff_start, 0);

			break;

		}



		/*

		 * The stripe extent starts before the range we want to delete:

		 *