[PATCH 02/12] xfs: factor out a xfs_validate_rt_geometry helper

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Christoph Hellwig <hch@xxxxxx>

Split the RT geometry validation in the early mount code into a
helper than can be reused by repair (from which this code was
apparently originally stolen anyway).

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
[djwong: u64 return value for calc_rbmblocks]
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_sb.c |   64 ++++++++++++++++++++++++++----------------------
 fs/xfs/libxfs/xfs_sb.h |    1 +
 2 files changed, 36 insertions(+), 29 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index b781e5f836e4c..a4221afb012b6 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -234,6 +234,38 @@ xfs_validate_sb_read(
 	return 0;
 }
 
+static uint64_t
+xfs_sb_calc_rbmblocks(
+	struct xfs_sb		*sbp)
+{
+	return howmany_64(sbp->sb_rextents, NBBY * sbp->sb_blocksize);
+}
+
+/* Validate the realtime geometry */
+bool
+xfs_validate_rt_geometry(
+	struct xfs_sb		*sbp)
+{
+	if (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE ||
+	    sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)
+		return false;
+
+	if (sbp->sb_rblocks == 0) {
+		if (sbp->sb_rextents != 0 || sbp->sb_rbmblocks != 0 ||
+		    sbp->sb_rextslog != 0 || sbp->sb_frextents != 0)
+			return false;
+		return true;
+	}
+
+	if (sbp->sb_rextents == 0 ||
+	    sbp->sb_rextents != div_u64(sbp->sb_rblocks, sbp->sb_rextsize) ||
+	    sbp->sb_rextslog != xfs_compute_rextslog(sbp->sb_rextents) ||
+	    sbp->sb_rbmblocks != xfs_sb_calc_rbmblocks(sbp))
+		return false;
+
+	return true;
+}
+
 /* Check all the superblock fields we care about when writing one out. */
 STATIC int
 xfs_validate_sb_write(
@@ -493,39 +525,13 @@ xfs_validate_sb_common(
 		}
 	}
 
-	/* Validate the realtime geometry; stolen from xfs_repair */
-	if (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE ||
-	    sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE) {
+	if (!xfs_validate_rt_geometry(sbp)) {
 		xfs_notice(mp,
-			"realtime extent sanity check failed");
+			"realtime %sgeometry check failed",
+			sbp->sb_rblocks ? "" : "zeroed ");
 		return -EFSCORRUPTED;
 	}
 
-	if (sbp->sb_rblocks == 0) {
-		if (sbp->sb_rextents != 0 || sbp->sb_rbmblocks != 0 ||
-		    sbp->sb_rextslog != 0 || sbp->sb_frextents != 0) {
-			xfs_notice(mp,
-				"realtime zeroed geometry check failed");
-			return -EFSCORRUPTED;
-		}
-	} else {
-		uint64_t	rexts;
-		uint64_t	rbmblocks;
-
-		rexts = div_u64(sbp->sb_rblocks, sbp->sb_rextsize);
-		rbmblocks = howmany_64(sbp->sb_rextents,
-				       NBBY * sbp->sb_blocksize);
-
-		if (sbp->sb_rextents == 0 ||
-		    sbp->sb_rextents != rexts ||
-		    sbp->sb_rextslog != xfs_compute_rextslog(rexts) ||
-		    sbp->sb_rbmblocks != rbmblocks) {
-			xfs_notice(mp,
-				"realtime geometry sanity check failed");
-			return -EFSCORRUPTED;
-		}
-	}
-
 	/*
 	 * Either (sb_unit and !hasdalign) or (!sb_unit and hasdalign)
 	 * would imply the image is corrupted.
diff --git a/fs/xfs/libxfs/xfs_sb.h b/fs/xfs/libxfs/xfs_sb.h
index 37b1ed1bc2095..796f02191dfd2 100644
--- a/fs/xfs/libxfs/xfs_sb.h
+++ b/fs/xfs/libxfs/xfs_sb.h
@@ -38,6 +38,7 @@ extern int	xfs_sb_get_secondary(struct xfs_mount *mp,
 bool	xfs_validate_stripe_geometry(struct xfs_mount *mp,
 		__s64 sunit, __s64 swidth, int sectorsize, bool may_repair,
 		bool silent);
+bool	xfs_validate_rt_geometry(struct xfs_sb *sbp);
 
 uint8_t xfs_compute_rextslog(xfs_rtbxlen_t rtextents);