From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Date: Mon, 13 Jan 2025 19:31:48 +0000 (+0100)
Subject: btrfs: implement hole punching for RAID stripe extents
X-Git-Tag: v6.14-rc1~207^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6aa0e7cc569eb24a7a99c70ad7477d454b3ac0ca;p=thirdparty%2Fkernel%2Flinux.git

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: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index c93f52a30a160..92071ca0655f0 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -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)
diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
index bf665fdef18b0..858abf518e9b4 100644
--- a/fs/btrfs/raid-stripe-tree.c
+++ b/fs/btrfs/raid-stripe-tree.c
@@ -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:
 		 *