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 c93f52a30a16028470594de1d1256dbec5c7899c..92071ca0655f0f1920eb841e77d3444a0e0d8834 100644 (file)
--- 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 bf665fdef18b016feca1f784b838a67cdc55e751..858abf518e9b4f16aa881e683ca893c3218412dd 100644 (file)
--- 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:
                 *