3 files changed, 50 insertions, 1 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b161224b5a0b..20793742c9d3 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2447,6 +2447,7 @@ enum btrfs_inline_ref_type {
 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
                                      struct btrfs_extent_inline_ref *iref,
                                      enum btrfs_inline_ref_type is_data);
+u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset);
 
 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes);
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index cd210550a349..5e8c6a0bac4b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -438,7 +438,7 @@ int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
         return BTRFS_REF_TYPE_INVALID;
 }
 
-static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
+u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 {
         u32 high_crc = ~(u32)0;
         u32 low_crc = ~(u32)0;
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index 0a56616bef9a..9645389a1187 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1187,6 +1187,51 @@ static int check_simple_keyed_refs(struct extent_buffer *leaf,
         return 0;
 }
 
+static int check_extent_data_ref(struct extent_buffer *leaf,
+                                 struct btrfs_key *key, int slot)
+{
+        struct btrfs_extent_data_ref *dref;
+        unsigned long ptr = btrfs_item_ptr_offset(leaf, slot);
+        const unsigned long end = ptr + btrfs_item_size_nr(leaf, slot);
+
+        if (btrfs_item_size_nr(leaf, slot) % sizeof(*dref) != 0) {
+                generic_err(leaf, slot,
+        "invalid item size, have %u expect aligned to %zu for key type %u",
+                            btrfs_item_size_nr(leaf, slot),
+                            sizeof(*dref), key->type);
+        }
+        if (!IS_ALIGNED(key->objectid, leaf->fs_info->sectorsize)) {
+                generic_err(leaf, slot,
+"invalid key objectid for shared block ref, have %llu expect aligned to %u",
+                            key->objectid, leaf->fs_info->sectorsize);
+                return -EUCLEAN;
+        }
+        for (; ptr < end; ptr += sizeof(*dref)) {
+                u64 root_objectid;
+                u64 owner;
+                u64 offset;
+                u64 hash;
+
+                dref = (struct btrfs_extent_data_ref *)ptr;
+                root_objectid = btrfs_extent_data_ref_root(leaf, dref);
+                owner = btrfs_extent_data_ref_objectid(leaf, dref);
+                offset = btrfs_extent_data_ref_offset(leaf, dref);
+                hash = hash_extent_data_ref(root_objectid, owner, offset);
+                if (hash != key->offset) {
+                        extent_err(leaf, slot,
+        "invalid extent data ref hash, item has 0x%016llx key has 0x%016llx",
+                                   hash, key->offset);
+                        return -EUCLEAN;
+                }
+                if (!IS_ALIGNED(offset, leaf->fs_info->sectorsize)) {
+                        extent_err(leaf, slot,
+        "invalid extent data backref offset, have %llu expect aligned to %u",
+                                   offset, leaf->fs_info->sectorsize);
+                }
+        }
+        return 0;
+}
+
 /*
  * Common point to switch the item-specific validation.
  */
@@ -1234,6 +1279,9 @@ static int check_leaf_item(struct extent_buffer *leaf,
         case BTRFS_SHARED_BLOCK_REF_KEY:
                 ret = check_simple_keyed_refs(leaf, key, slot);
                 break;
+        case BTRFS_EXTENT_DATA_REF_KEY:
+                ret = check_extent_data_ref(leaf, key, slot);
+                break;
         }
         return ret;
 }