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Commit 85d4198e authored by Yan Zheng's avatar Yan Zheng Committed by Chris Mason
Browse files

Btrfs: check duplicate backrefs for both data and metadata 



lookup_inline_extent_backref only checks for duplicate backref for data
extents. It assumes backrefs for tree block never conflict.

This patch makes lookup_inline_extent_backref check for duplicate backrefs
for both data and tree block, so that we can detect potential bug earlier.
This is a safety check, strictly speaking it is not required.

Signed-off-by: default avatarYan Zheng <zheng.yan@oracle.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent fd0fb038

fs/btrfs/extent-tree.c

+4 −11
Original line number Diff line number Diff line
@@ -1056,7 +1056,6 @@ int lookup_inline_extent_backref(struct btrfs_trans_handle *trans, 
	want = extent_ref_type(parent, owner);

	if (insert) {

		extra_size = btrfs_extent_inline_ref_size(want);

		if (owner >= BTRFS_FIRST_FREE_OBJECTID)

		path->keep_locks = 1;

	} else

		extra_size = -1;
@@ -1087,12 +1086,6 @@ int lookup_inline_extent_backref(struct btrfs_trans_handle *trans, 
#endif

	BUG_ON(item_size < sizeof(*ei));



	if (owner < BTRFS_FIRST_FREE_OBJECTID && insert &&

	    item_size + extra_size >= BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {

		err = -EAGAIN;

		goto out;

	}



	ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);

	flags = btrfs_extent_flags(leaf, ei);
@@ -1165,15 +1158,15 @@ int lookup_inline_extent_backref(struct btrfs_trans_handle *trans, 
		 * For simplicity, we just do not add new inline back

		 * ref if there is any kind of item for this block

		 */

		if (owner >= BTRFS_FIRST_FREE_OBJECTID &&

		    find_next_key(path, &key) == 0 && key.objectid == bytenr) {

		if (find_next_key(path, &key) == 0 && key.objectid == bytenr &&

		    key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {

			err = -EAGAIN;

			goto out;

		}

	}

	*ref_ret = (struct btrfs_extent_inline_ref *)ptr;

out:

	if (insert && owner >= BTRFS_FIRST_FREE_OBJECTID) {

	if (insert) {

		path->keep_locks = 0;

		btrfs_unlock_up_safe(path, 1);

	}