Commit 5846a3c2 authored by Qu Wenruo's avatar Qu Wenruo Committed by Chris Mason
Browse files

btrfs: qgroup: Fix a race in delayed_ref which leads to abort trans 



Between btrfs_allocerved_file_extent() and
btrfs_add_delayed_qgroup_reserve(), there is a window that delayed_refs
are run and delayed ref head maybe freed before
btrfs_add_delayed_qgroup_reserve().

This will cause btrfs_dad_delayed_qgroup_reserve() to return -ENOENT,
and cause transaction to be aborted.

This patch will record qgroup reserve space info into delayed_ref_head
at btrfs_add_delayed_ref(), to eliminate the race window.

Reported-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 69624913

fs/btrfs/ctree.h

+2 −1
Original line number Diff line number Diff line
@@ -3430,7 +3430,8 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans, 
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,

				     struct btrfs_root *root,

				     u64 root_objectid, u64 owner,

				     u64 offset, struct btrfs_key *ins);

				     u64 offset, u64 ram_bytes,

				     struct btrfs_key *ins);

int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,

				   struct btrfs_root *root,

				   u64 root_objectid, u64 owner, u64 offset,

fs/btrfs/delayed-ref.c

+17 −5
Original line number Diff line number Diff line
@@ -535,7 +535,8 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info, 
		     struct btrfs_trans_handle *trans,

		     struct btrfs_delayed_ref_node *ref,

		     struct btrfs_qgroup_extent_record *qrecord,

		     u64 bytenr, u64 num_bytes, int action, int is_data)

		     u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,

		     int action, int is_data)

{

	struct btrfs_delayed_ref_head *existing;

	struct btrfs_delayed_ref_head *head_ref = NULL;
@@ -544,6 +545,9 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info, 
	int count_mod = 1;

	int must_insert_reserved = 0;



	/* If reserved is provided, it must be a data extent. */

	BUG_ON(!is_data && reserved);



	/*

	 * the head node stores the sum of all the mods, so dropping a ref

	 * should drop the sum in the head node by one.
@@ -593,6 +597,11 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info, 


	/* Record qgroup extent info if provided */

	if (qrecord) {

		if (ref_root && reserved) {

			head_ref->qgroup_ref_root = ref_root;

			head_ref->qgroup_reserved = reserved;

		}



		qrecord->bytenr = bytenr;

		qrecord->num_bytes = num_bytes;

		qrecord->old_roots = NULL;
@@ -611,6 +620,8 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info, 
	existing = htree_insert(&delayed_refs->href_root,

				&head_ref->href_node);

	if (existing) {

		WARN_ON(ref_root && reserved && existing->qgroup_ref_root

			&& existing->qgroup_reserved);

		update_existing_head_ref(delayed_refs, &existing->node, ref);

		/*

		 * we've updated the existing ref, free the newly
@@ -777,7 +788,7 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info, 
	 * the spin lock

	 */

	head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,

					bytenr, num_bytes, action, 0);

					bytenr, num_bytes, 0, 0, action, 0);



	add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,

			     num_bytes, parent, ref_root, level, action);
@@ -800,7 +811,7 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, 
			       struct btrfs_trans_handle *trans,

			       u64 bytenr, u64 num_bytes,

			       u64 parent, u64 ref_root,

			       u64 owner, u64 offset, int action,

			       u64 owner, u64 offset, u64 reserved, int action,

			       struct btrfs_delayed_extent_op *extent_op)

{

	struct btrfs_delayed_data_ref *ref;
@@ -839,7 +850,8 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, 
	 * the spin lock

	 */

	head_ref = add_delayed_ref_head(fs_info, trans, &head_ref->node, record,

					bytenr, num_bytes, action, 1);

					bytenr, num_bytes, ref_root, reserved,

					action, 1);



	add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,

				   num_bytes, parent, ref_root, owner, offset,
@@ -894,7 +906,7 @@ int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info, 
	spin_lock(&delayed_refs->lock);



	add_delayed_ref_head(fs_info, trans, &head_ref->node, NULL, bytenr,

			     num_bytes, BTRFS_UPDATE_DELAYED_HEAD,

			     num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,

			     extent_op->is_data);



	spin_unlock(&delayed_refs->lock);

fs/btrfs/delayed-ref.h

+1 −1
Original line number Diff line number Diff line
@@ -248,7 +248,7 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info, 
			       struct btrfs_trans_handle *trans,

			       u64 bytenr, u64 num_bytes,

			       u64 parent, u64 ref_root,

			       u64 owner, u64 offset, int action,

			       u64 owner, u64 offset, u64 reserved, int action,

			       struct btrfs_delayed_extent_op *extent_op);

int btrfs_add_delayed_qgroup_reserve(struct btrfs_fs_info *fs_info,

				     struct btrfs_trans_handle *trans,

fs/btrfs/extent-tree.c

+8 −6
Original line number Diff line number Diff line
@@ -2087,8 +2087,8 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans, 
					BTRFS_ADD_DELAYED_REF, NULL);

	} else {

		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,

					num_bytes,

					parent, root_objectid, owner, offset,

					num_bytes, parent, root_objectid,

					owner, offset, 0,

					BTRFS_ADD_DELAYED_REF, NULL);

	}

	return ret;
@@ -6832,8 +6832,8 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,

						num_bytes,

						parent, root_objectid, owner,

						offset, BTRFS_DROP_DELAYED_REF,

						NULL);

						offset, 0,

						BTRFS_DROP_DELAYED_REF, NULL);

	}

	return ret;

}
@@ -7759,7 +7759,8 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans, 
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,

				     struct btrfs_root *root,

				     u64 root_objectid, u64 owner,

				     u64 offset, struct btrfs_key *ins)

				     u64 offset, u64 ram_bytes,

				     struct btrfs_key *ins)

{

	int ret;
@@ -7768,7 +7769,8 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans, 
	ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,

					 ins->offset, 0,

					 root_objectid, owner, offset,

					 BTRFS_ADD_DELAYED_EXTENT, NULL);

					 ram_bytes, BTRFS_ADD_DELAYED_EXTENT,

					 NULL);

	return ret;

}

fs/btrfs/inode.c

+4 −8
Original line number Diff line number Diff line
@@ -2127,17 +2127,13 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans, 
	ins.type = BTRFS_EXTENT_ITEM_KEY;

	ret = btrfs_alloc_reserved_file_extent(trans, root,

					root->root_key.objectid,

					btrfs_ino(inode), file_pos, &ins);

	if (ret < 0)

		goto out;

					btrfs_ino(inode), file_pos,

					ram_bytes, &ins);

	/*

	 * Release the reserved range from inode dirty range map, and

	 * move it to delayed ref codes, as now accounting only happens at

	 * commit_transaction() time.

	 * Release the reserved range from inode dirty range map, as it is

	 * already moved into delayed_ref_head

	 */

	btrfs_qgroup_release_data(inode, file_pos, ram_bytes);

	ret = btrfs_add_delayed_qgroup_reserve(root->fs_info, trans,

			root->objectid, disk_bytenr, ram_bytes);

out:

	btrfs_free_path(path);

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