1 files changed, 70 insertions, 10 deletions

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index f4e84aa1d50a..a20cade590e9 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -31,15 +31,66 @@
  */
 
 /*
+ * Check that all the V4 feature bits that the V5 filesystem format requires are
+ * correctly set.
+ */
+static bool
+xfs_sb_validate_v5_features(
+	struct xfs_sb	*sbp)
+{
+	/* We must not have any unknown V4 feature bits set */
+	if (sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS)
+		return false;
+
+	/*
+	 * The CRC bit is considered an invalid V4 flag, so we have to add it
+	 * manually to the OKBITS mask.
+	 */
+	if (sbp->sb_features2 & ~(XFS_SB_VERSION2_OKBITS |
+				  XFS_SB_VERSION2_CRCBIT))
+		return false;
+
+	/* Now check all the required V4 feature flags are set. */
+
+#define V5_VERS_FLAGS	(XFS_SB_VERSION_NLINKBIT	| \
+			XFS_SB_VERSION_ALIGNBIT		| \
+			XFS_SB_VERSION_LOGV2BIT		| \
+			XFS_SB_VERSION_EXTFLGBIT	| \
+			XFS_SB_VERSION_DIRV2BIT		| \
+			XFS_SB_VERSION_MOREBITSBIT)
+
+#define V5_FEAT_FLAGS	(XFS_SB_VERSION2_LAZYSBCOUNTBIT	| \
+			XFS_SB_VERSION2_ATTR2BIT	| \
+			XFS_SB_VERSION2_PROJID32BIT	| \
+			XFS_SB_VERSION2_CRCBIT)
+
+	if ((sbp->sb_versionnum & V5_VERS_FLAGS) != V5_VERS_FLAGS)
+		return false;
+	if ((sbp->sb_features2 & V5_FEAT_FLAGS) != V5_FEAT_FLAGS)
+		return false;
+	return true;
+}
+
+/*
  * We support all XFS versions newer than a v4 superblock with V2 directories.
  */
 bool
 xfs_sb_good_version(
 	struct xfs_sb	*sbp)
 {
-	/* all v5 filesystems are supported */
+	/*
+	 * All v5 filesystems are supported, but we must check that all the
+	 * required v4 feature flags are enabled correctly as the code checks
+	 * those flags and not for v5 support.
+	 */
 	if (xfs_sb_is_v5(sbp))
-		return true;
+		return xfs_sb_validate_v5_features(sbp);
+
+	/* We must not have any unknown v4 feature bits set */
+	if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) ||
+	    ((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) &&
+	     (sbp->sb_features2 & ~XFS_SB_VERSION2_OKBITS)))
+		return false;
 
 	/* versions prior to v4 are not supported */
 	if (XFS_SB_VERSION_NUM(sbp) < XFS_SB_VERSION_4)
@@ -51,12 +102,6 @@ xfs_sb_good_version(
 	if (!(sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT))
 		return false;
 
-	/* And must not have any unknown v4 feature bits set */
-	if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) ||
-	    ((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) &&
-	     (sbp->sb_features2 & ~XFS_SB_VERSION2_OKBITS)))
-		return false;
-
 	/* It's a supported v4 filesystem */
 	return true;
 }
@@ -70,6 +115,8 @@ xfs_sb_version_to_features(
 	/* optional V4 features */
 	if (sbp->sb_rblocks > 0)
 		features |= XFS_FEAT_REALTIME;
+	if (sbp->sb_versionnum & XFS_SB_VERSION_NLINKBIT)
+		features |= XFS_FEAT_NLINK;
 	if (sbp->sb_versionnum & XFS_SB_VERSION_ATTRBIT)
 		features |= XFS_FEAT_ATTR;
 	if (sbp->sb_versionnum & XFS_SB_VERSION_QUOTABIT)
@@ -124,6 +171,9 @@ xfs_sb_version_to_features(
 		features |= XFS_FEAT_BIGTIME;
 	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR)
 		features |= XFS_FEAT_NEEDSREPAIR;
+	if (sbp->sb_features_incompat & XFS_SB_FEAT_INCOMPAT_NREXT64)
+		features |= XFS_FEAT_NREXT64;
+
 	return features;
 }
 
@@ -262,12 +312,15 @@ xfs_validate_sb_common(
 	bool			has_dalign;
 
 	if (!xfs_verify_magic(bp, dsb->sb_magicnum)) {
-		xfs_warn(mp, "bad magic number");
+		xfs_warn(mp,
+"Superblock has bad magic number 0x%x. Not an XFS filesystem?",
+			be32_to_cpu(dsb->sb_magicnum));
 		return -EWRONGFS;
 	}
 
 	if (!xfs_sb_good_version(sbp)) {
-		xfs_warn(mp, "bad version");
+		xfs_warn(mp,
+"Superblock has unknown features enabled or corrupted feature masks.");
 		return -EWRONGFS;
 	}
 
@@ -911,6 +964,11 @@ xfs_log_sb(
 	 * reservations that have been taken out percpu counters. If we have an
 	 * unclean shutdown, this will be corrected by log recovery rebuilding
 	 * the counters from the AGF block counts.
+	 *
+	 * Do not update sb_frextents here because it is not part of the lazy
+	 * sb counters, despite having a percpu counter. It is always kept
+	 * consistent with the ondisk rtbitmap by xfs_trans_apply_sb_deltas()
+	 * and hence we don't need have to update it here.
 	 */
 	if (xfs_has_lazysbcount(mp)) {
 		mp->m_sb.sb_icount = percpu_counter_sum(&mp->m_icount);
@@ -1135,6 +1193,8 @@ xfs_fs_geometry(
 	} else {
 		geo->logsectsize = BBSIZE;
 	}
+	if (xfs_has_large_extent_counts(mp))
+		geo->flags |= XFS_FSOP_GEOM_FLAGS_NREXT64;
 	geo->rtsectsize = sbp->sb_blocksize;
 	geo->dirblocksize = xfs_dir2_dirblock_bytes(sbp);