[PATCH 17/24] xfs: refactor domain and refcount checking

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Source kernel commit: ea3d9e89f37160240af1c9f1706d17fea9e20ce9

Create a helper function to ensure that CoW staging extent records have
a single refcount and that shared extent records have more than 1
refcount.  We'll put this to more use in the next patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 libxfs/xfs_refcount.c |    5 +----
 libxfs/xfs_refcount.h |   12 ++++++++++++
 2 files changed, 13 insertions(+), 4 deletions(-)


diff --git a/libxfs/xfs_refcount.c b/libxfs/xfs_refcount.c
index 7094a27dce..f0fc96da6a 100644
--- a/libxfs/xfs_refcount.c
+++ b/libxfs/xfs_refcount.c
@@ -141,10 +141,7 @@ xfs_refcount_get_rec(
 	if (irec->rc_blockcount == 0 || irec->rc_blockcount > MAXREFCEXTLEN)
 		goto out_bad_rec;
 
-	/* handle special COW-staging domain */
-	if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
-		goto out_bad_rec;
-	if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
+	if (!xfs_refcount_check_domain(irec))
 		goto out_bad_rec;
 
 	/* check for valid extent range, including overflow */
diff --git a/libxfs/xfs_refcount.h b/libxfs/xfs_refcount.h
index 3beb5a30a9..ee32e8eb5a 100644
--- a/libxfs/xfs_refcount.h
+++ b/libxfs/xfs_refcount.h
@@ -55,6 +55,18 @@ struct xfs_refcount_intent {
 	xfs_fsblock_t				ri_startblock;
 };
 
+/* Check that the refcount is appropriate for the record domain. */
+static inline bool
+xfs_refcount_check_domain(
+	const struct xfs_refcount_irec	*irec)
+{
+	if (irec->rc_domain == XFS_REFC_DOMAIN_COW && irec->rc_refcount != 1)
+		return false;
+	if (irec->rc_domain == XFS_REFC_DOMAIN_SHARED && irec->rc_refcount < 2)
+		return false;
+	return true;
+}
+
 void xfs_refcount_increase_extent(struct xfs_trans *tp,
 		struct xfs_bmbt_irec *irec);
 void xfs_refcount_decrease_extent(struct xfs_trans *tp,