Commit bf59a5a2 authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW 



For similar reasons as BTRFS_NESTING_COW, we need
BTRFS_NESTING_LEFT/RIGHT_COW.  The pattern is this

lock leaf -> BTRFS_NESTING_NORMAL
  cow leaf -> BTRFS_NESTING_COW
    split leaf
      lock left -> BTRFS_NESTING_LEFT
        cow left -> BTRFS_NESTING_LEFT_COW

We need this in order to indicate to lockdep that these locks are
discrete and are being taken in a safe order.

Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent bf77467a

fs/btrfs/ctree.c

+6 −6
Original line number Diff line number Diff line
@@ -1900,7 +1900,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		btrfs_set_lock_blocking_write(left);

		wret = btrfs_cow_block(trans, root, left,

				       parent, pslot - 1, &left,

				       BTRFS_NESTING_COW);

				       BTRFS_NESTING_LEFT_COW);

		if (wret) {

			ret = wret;

			goto enospc;
@@ -1916,7 +1916,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		btrfs_set_lock_blocking_write(right);

		wret = btrfs_cow_block(trans, root, right,

				       parent, pslot + 1, &right,

				       BTRFS_NESTING_COW);

				       BTRFS_NESTING_RIGHT_COW);

		if (wret) {

			ret = wret;

			goto enospc;
@@ -2085,7 +2085,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, 
		} else {

			ret = btrfs_cow_block(trans, root, left, parent,

					      pslot - 1, &left,

					      BTRFS_NESTING_COW);

					      BTRFS_NESTING_LEFT_COW);

			if (ret)

				wret = 1;

			else {
@@ -2140,7 +2140,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, 
		} else {

			ret = btrfs_cow_block(trans, root, right,

					      parent, pslot + 1,

					      &right, BTRFS_NESTING_COW);

					      &right, BTRFS_NESTING_RIGHT_COW);

			if (ret)

				wret = 1;

			else {
@@ -3815,7 +3815,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root 


	/* cow and double check */

	ret = btrfs_cow_block(trans, root, right, upper,

			      slot + 1, &right, BTRFS_NESTING_COW);

			      slot + 1, &right, BTRFS_NESTING_RIGHT_COW);

	if (ret)

		goto out_unlock;
@@ -4057,7 +4057,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root 
	/* cow and double check */

	ret = btrfs_cow_block(trans, root, left,

			      path->nodes[1], slot - 1, &left,

			      BTRFS_NESTING_COW);

			      BTRFS_NESTING_LEFT_COW);

	if (ret) {

		/* we hit -ENOSPC, but it isn't fatal here */

		if (ret == -ENOSPC)

fs/btrfs/locking.h

+8 −0
Original line number Diff line number Diff line
@@ -44,6 +44,14 @@ enum btrfs_lock_nesting { 
	BTRFS_NESTING_LEFT,

	BTRFS_NESTING_RIGHT,



	/*

	 * When splitting we will be holding a lock on the left/right node when

	 * we need to cow that node, thus we need a new set of subclasses for

	 * these two operations.

	 */

	BTRFS_NESTING_LEFT_COW,

	BTRFS_NESTING_RIGHT_COW,



	/*

	 * We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so

	 * add this in here and add a static_assert to keep us from going over